[PATCH 00/15] sysfs support for namespaces

[PATCH 00/15] sysfs support for namespaces

[Eric W. Biederman]

When multiple namespaces are in use we can get multiple kernel objects
with the same name which is currently impossible to represent in sysfs.
In particular directories like /sys/class/net and /sys/kernel/uids have
significant problems.

Not wanting to change the user space interface and wanting to have a simple
implementation where all objects are in the kobject and sysfs trees.  The
decision has been made to tag objects with the namespace they live in,
and in a particular mount of sysfs only display objects with the tag
that corresponds to the namespaces in effect when sysfs was mounted.

After the last round of reviews the mount/umount logic is
significantly cleaned up and easier to maintain.  From a 10,000
foot view the code and the way it functions has remained the
same since we settled on tagged directories a year or so ago.   I
intend any future cleanups to be as incremental patches on top
of this existing set.

Lack of these patches are keeping the generally complete network
namespace work in 2.6.26 from being used and tested more heavily.
Can we please get the patches merged?

These patches are based off of 2.6.26-rc8 + the -gregkh tree from
last night.  Hopefully that means they apply -mm -gregkh and
-linux-next.

Eric

[PATCH 01/15] kobject: Cleanup kobject_rename and !CONFIG_SYSFS

[Eric W. Biederman]

It finally dawned on me what the clean fix to sysfs_rename_dir
calling kobject_set_name is.  Move the work into kobject_rename
where it belongs.  The callers serialize us anyway so this is
safe.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/dir.c        |    6 +-----
 include/linux/sysfs.h |    4 +---
 lib/kobject.c         |   17 +++++++++++++++--
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 8c0e4b9..146b86a 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -799,16 +799,12 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	if (!new_dentry)
 		goto out_unlock;
 
-	/* rename kobject and sysfs_dirent */
+	/* rename sysfs_dirent */
 	error = -ENOMEM;
 	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
 	if (!new_name)
 		goto out_unlock;
 
-	error = kobject_set_name(kobj, "%s", new_name);
-	if (error)
-		goto out_unlock;
-
 	dup_name = sd->s_name;
 	sd->s_name = new_name;
 
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 84d92bb..f7e43ed 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -20,8 +20,6 @@
 struct kobject;
 struct module;
 
-extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
-			    __attribute__((format(printf, 2, 3)));
 /* FIXME
  * The *owner field is no longer used, but leave around
  * until the tree gets cleaned up fully.
@@ -140,7 +138,7 @@ static inline void sysfs_remove_dir(struct kobject *kobj)
 
 static inline int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
 {
-	return kobject_set_name(kobj, "%s", new_name);
+	return 0;
 }
 
 static inline int sysfs_move_dir(struct kobject *kobj,
diff --git a/lib/kobject.c b/lib/kobject.c
index 829b839..49b3bc4 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -451,6 +451,7 @@ int kobject_rename(struct kobject *kobj, const char *new_name)
 {
 	int error = 0;
 	const char *devpath = NULL;
+	const char *dup_name = NULL, *name;
 	char *devpath_string = NULL;
 	char *envp[2];
 
@@ -474,15 +475,27 @@ int kobject_rename(struct kobject *kobj, const char *new_name)
 	envp[0] = devpath_string;
 	envp[1] = NULL;
 
+	name = dup_name = kstrdup(new_name, GFP_KERNEL);
+	if (!name) {
+		error = -ENOMEM;
+		goto out;
+	}
+
 	error = sysfs_rename_dir(kobj, new_name);
+	if (error)
+		goto out;
+
+	/* Install the new kobject name */
+	dup_name = kobj->name;
+	kobj->name = name;
 
 	/* This function is mostly/only used for network interface.
 	 * Some hotplug package track interfaces by their name and
 	 * therefore want to know when the name is changed by the user. */
-	if (!error)
-		kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 
 out:
+	kfree(dup_name);
 	kfree(devpath_string);
 	kfree(devpath);
 	kobject_put(kobj);
-- 
1.5.3.rc6.17.g1911

[PATCH 02/15] sysfs: Support for preventing unmounts.

[Eric W. Biederman]

To support mounting multiple instances of sysfs occassionally I
need to walk through all of the currently present sysfs super blocks.

To allow this iteration this patch adds sysfs_grab_supers
and sysfs_release_supers.  While a piece of code is in
a section surrounded by these no more sysfs super blocks
will be either created or destroyed.

So the fundamentals.
- The data in sysfs fundamentally changes behind the back of the
  VFS and we need to keep the VFS in sync.  Essentially this is the
  distributed filesystem problem.

- In particular for sysfs_rename and sysfs_move_dir we need to support finding
  the dcache entries and calling d_move.  So that the dcache does not
  get into an inconsistent state.  Timeouts and invalidates like NFS
  uses are to be  avoided if at all possible.

- Coming through the vfs we are guaranteed that the filesystem will
  not be unmounted while we have a reference on a dentry, and with
  multiple mounts we do not get that guarantee.  Therefore to get that
  guarantee for all of the superblocks we need the blunt instrument.

- Since mount/unmount are rare blocking them is no big deal.

I believe any distributed filesystem that is together enough to tell
us about renames (so we can update the dcache) instead of doing the
NFS timeout will need the ability to block mount/unmount while it is
executing d_move.

Currently sysfs does not need to block mounts only because we perform
an internal mount and then never unmount sysfs.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/mount.c |   79 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 fs/sysfs/sysfs.h |   10 +++++++
 2 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 9f328d2..c812cc4 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -41,47 +41,110 @@ struct sysfs_dirent sysfs_root = {
 
 static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 {
-	struct inode *inode;
-	struct dentry *root;
+	struct sysfs_super_info *info = NULL;
+	struct inode *inode = NULL;
+	struct dentry *root = NULL;
+	int error;
 
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = SYSFS_MAGIC;
 	sb->s_op = &sysfs_ops;
 	sb->s_time_gran = 1;
-	sysfs_sb = sb;
+	if (!sysfs_sb)
+		sysfs_sb = sb;
+
+	error = -ENOMEM;
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		goto out_err;
 
 	/* get root inode, initialize and unlock it */
+	error = -ENOMEM;
 	inode = sysfs_get_inode(&sysfs_root);
 	if (!inode) {
 		pr_debug("sysfs: could not get root inode\n");
-		return -ENOMEM;
+		goto out_err;
 	}
 
 	/* instantiate and link root dentry */
+	error = -ENOMEM;
 	root = d_alloc_root(inode);
 	if (!root) {
 		pr_debug("%s: could not get root dentry!\n",__func__);
-		iput(inode);
-		return -ENOMEM;
+		goto out_err;
 	}
 	root->d_fsdata = &sysfs_root;
 	sb->s_root = root;
+	sb->s_fs_info = info;
 	return 0;
+
+out_err:
+	dput(root);
+	iput(inode);
+	kfree(info);
+	if (sysfs_sb == sb)
+		sysfs_sb = NULL;
+	return error;
 }
 
 static int sysfs_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
-	return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
+	int rc;
+	mutex_lock(&sysfs_rename_mutex);
+	rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
+	mutex_unlock(&sysfs_rename_mutex);
+	return rc;
 }
 
-static struct file_system_type sysfs_fs_type = {
+struct file_system_type sysfs_fs_type = {
 	.name		= "sysfs",
 	.get_sb		= sysfs_get_sb,
 	.kill_sb	= kill_anon_super,
 };
 
+void sysfs_grab_supers(void)
+{
+	/* must hold sysfs_rename_mutex */
+	struct super_block *sb;
+	/* Loop until I have taken s_umount on all sysfs superblocks */
+restart:
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		if (sysfs_info(sb)->grabbed)
+			continue;
+		/* Wait for unmount activity to complete. */
+		if (sb->s_count < S_BIAS) {
+			sb->s_count += 1;
+			spin_unlock(&sb_lock);
+			down_read(&sb->s_umount);
+			drop_super(sb);
+			goto restart;
+		}
+		atomic_inc(&sb->s_active);
+		sysfs_info(sb)->grabbed = 1;
+	}
+	spin_unlock(&sb_lock);
+}
+
+void sysfs_release_supers(void)
+{
+	/* must hold sysfs_rename_mutex */
+	struct super_block *sb;
+restart:
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		if (!sysfs_info(sb)->grabbed)
+			continue;
+		sysfs_info(sb)->grabbed = 0;
+		spin_unlock(&sb_lock);
+		deactivate_super(sb);
+		goto restart;
+	}
+	spin_unlock(&sb_lock);
+}
+
 int __init sysfs_init(void)
 {
 	int err = -ENOMEM;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 2915959..0fdc3de 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -85,6 +85,12 @@ struct sysfs_addrm_cxt {
 	int			cnt;
 };
 
+struct sysfs_super_info {
+	int	grabbed;
+};
+
+#define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
+
 /*
  * mount.c
  */
@@ -92,6 +98,10 @@ extern struct sysfs_dirent sysfs_root;
 extern struct super_block *sysfs_sb;
 extern struct kmem_cache *sysfs_dir_cachep;
 extern struct vfsmount *sysfs_mount;
+extern struct file_system_type sysfs_fs_type;
+
+void sysfs_grab_supers(void);
+void sysfs_release_supers(void);
 
 /*
  * dir.c
-- 
1.5.3.rc6.17.g1911

[PATCH 03/15] sysfs: sysfs_get_dentry add a sb parameter

[Eric W. Biederman]

In preparation for multiple mounts of sysfs add a superblock parameter to
sysfs_get_dentry.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/dir.c   |   12 +++++++-----
 fs/sysfs/file.c  |    2 +-
 fs/sysfs/sysfs.h |    3 ++-
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 146b86a..69c40ed 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -85,6 +85,7 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
 
 /**
  *	sysfs_get_dentry - get dentry for the given sysfs_dirent
+ *	@sb: superblock of the dentry to return
  *	@sd: sysfs_dirent of interest
  *
  *	Get dentry for @sd.  Dentry is looked up if currently not
@@ -97,9 +98,10 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
  *	RETURNS:
  *	Pointer to found dentry on success, ERR_PTR() value on error.
  */
-struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
+struct dentry *sysfs_get_dentry(struct super_block *sb,
+				struct sysfs_dirent *sd)
 {
-	struct dentry *dentry = dget(sysfs_sb->s_root);
+	struct dentry *dentry = dget(sb->s_root);
 
 	while (dentry->d_fsdata != sd) {
 		struct sysfs_dirent *cur;
@@ -777,7 +779,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 		goto out;	/* nothing to rename */
 
 	/* get the original dentry */
-	old_dentry = sysfs_get_dentry(sd);
+	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
 	if (IS_ERR(old_dentry)) {
 		error = PTR_ERR(old_dentry);
 		old_dentry = NULL;
@@ -841,7 +843,7 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 		goto out;	/* nothing to move */
 
 	/* get dentries */
-	old_dentry = sysfs_get_dentry(sd);
+	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
 	if (IS_ERR(old_dentry)) {
 		error = PTR_ERR(old_dentry);
 		old_dentry = NULL;
@@ -849,7 +851,7 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 	}
 	old_parent = old_dentry->d_parent;
 
-	new_parent = sysfs_get_dentry(new_parent_sd);
+	new_parent = sysfs_get_dentry(sysfs_sb, new_parent_sd);
 	if (IS_ERR(new_parent)) {
 		error = PTR_ERR(new_parent);
 		new_parent = NULL;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 15ff679..cb5dd3f 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -585,7 +585,7 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 		goto out;
 
 	mutex_lock(&sysfs_rename_mutex);
-	victim = sysfs_get_dentry(victim_sd);
+	victim = sysfs_get_dentry(sysfs_sb, victim_sd);
 	mutex_unlock(&sysfs_rename_mutex);
 	if (IS_ERR(victim)) {
 		rc = PTR_ERR(victim);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 0fdc3de..b1bdc6e 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -113,7 +113,8 @@ extern spinlock_t sysfs_assoc_lock;
 extern const struct file_operations sysfs_dir_operations;
 extern const struct inode_operations sysfs_dir_inode_operations;
 
-struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);
+struct dentry *sysfs_get_dentry(struct super_block *sb,
+				struct sysfs_dirent *sd);
 struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd);
 void sysfs_put_active_two(struct sysfs_dirent *sd);
 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
-- 
1.5.3.rc6.17.g1911

[PATCH 04/15] sysfs: Implement __sysfs_get_dentry

[Eric W. Biederman]

This function is similar but much simpler to sysfs_get_dentry
returns a sysfs dentry if one curently exists.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/dir.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 69c40ed..df9934a 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -764,6 +764,45 @@ void sysfs_remove_dir(struct kobject * kobj)
 	__sysfs_remove_dir(sd);
 }
 
+/**
+ *	__sysfs_get_dentry - get dentry for the given sysfs_dirent
+ *	@sb: superblock of the dentry to return
+ *	@sd: sysfs_dirent of interest
+ *
+ *	Get dentry for @sd.  Only return a dentry if one currently
+ *	exists.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	Pointer to found dentry on success, NULL on failure.
+ */
+static struct dentry *__sysfs_get_dentry(struct super_block *sb,
+					 struct sysfs_dirent *sd)
+{
+	struct inode *inode;
+	struct dentry *dentry = NULL;
+
+	inode = ilookup5_nowait(sysfs_sb, sd->s_ino, sysfs_ilookup_test, sd);
+	if (inode && !(inode->i_state & I_NEW)) {
+		struct dentry *alias;
+		spin_lock(&dcache_lock);
+		list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+			if (!IS_ROOT(alias) && d_unhashed(alias))
+				continue;
+			if (alias->d_sb != sb)
+				continue;
+			dentry = alias;
+			dget_locked(dentry);
+			break;
+		}
+		spin_unlock(&dcache_lock);
+	}
+	iput(inode);
+	return dentry;
+}
+
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 {
 	struct sysfs_dirent *sd = kobj->sd;
-- 
1.5.3.rc6.17.g1911

[PATCH 05/15] sysfs: Rename Support multiple superblocks

[Eric W. Biederman]

This patch modifies the sysfs_rename_dir and sysfs_move_dir routines
to support multiple sysfs dentry tries rooted in different
sysfs superblocks.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/dir.c |  193 +++++++++++++++++++++++++++++++++++++++-----------------
 1 files changed, 136 insertions(+), 57 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index df9934a..b2d92ea 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -803,43 +803,113 @@ static struct dentry *__sysfs_get_dentry(struct super_block *sb,
 	return dentry;
 }
 
+struct sysfs_rename_struct {
+	struct list_head list;
+	struct dentry *old_dentry;
+	struct dentry *new_dentry;
+	struct dentry *old_parent;
+	struct dentry *new_parent;
+};
+
+static void post_rename(struct list_head *head)
+{
+	struct sysfs_rename_struct *srs;
+	while (!list_empty(head)) {
+		srs = list_entry(head->next, struct sysfs_rename_struct, list);
+		dput(srs->old_dentry);
+		dput(srs->new_dentry);
+		dput(srs->old_parent);
+		dput(srs->new_parent);
+		list_del(&srs->list);
+		kfree(srs);
+	}
+}
+
+static int prep_rename(struct list_head *head,
+	struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd,
+	const char *name)
+{
+	struct sysfs_rename_struct *srs;
+	struct super_block *sb;
+	struct dentry *dentry;
+	int error;
+
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		dentry = sysfs_get_dentry(sb, sd);
+		if (dentry == ERR_PTR(-EXDEV))
+			continue;
+		if (IS_ERR(dentry)) {
+			error = PTR_ERR(dentry);
+			goto err_out;
+		}
+
+		srs = kzalloc(sizeof(*srs), GFP_KERNEL);
+		if (!srs) {
+			error = -ENOMEM;
+			dput(dentry);
+			goto err_out;
+		}
+
+		INIT_LIST_HEAD(&srs->list);
+		list_add(head, &srs->list);
+		srs->old_dentry = dentry;
+		srs->old_parent = dget(dentry->d_parent);
+
+		dentry = sysfs_get_dentry(sb, new_parent_sd);
+		if (IS_ERR(dentry)) {
+			error = PTR_ERR(dentry);
+			goto err_out;
+		}
+		srs->new_parent = dentry;
+
+		error = -ENOMEM;
+		dentry = d_alloc_name(srs->new_parent, name);
+		if (!dentry)
+			goto err_out;
+		srs->new_dentry = dentry;
+	}
+	return 0;
+
+err_out:
+	post_rename(head);
+	return error;
+}
+
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 {
 	struct sysfs_dirent *sd = kobj->sd;
-	struct dentry *parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
+	struct list_head todo;
+	struct sysfs_rename_struct *srs;
+	struct inode *parent_inode = NULL;
 	const char *dup_name = NULL;
 	int error;
 
+	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 
 	error = 0;
 	if (strcmp(sd->s_name, new_name) == 0)
 		goto out;	/* nothing to rename */
 
-	/* get the original dentry */
-	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
-	}
+	sysfs_grab_supers();
+	error = prep_rename(&todo, sd, sd->s_parent, new_name);
+	if (error)
+		goto out_release;
 
-	parent = old_dentry->d_parent;
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	parent_inode = sysfs_get_inode(sd->s_parent);
+	mutex_unlock(&sysfs_mutex);
+	if (!parent_inode)
+		goto out_release;
 
-	/* lock parent and get dentry for new name */
-	mutex_lock(&parent->d_inode->i_mutex);
+	mutex_lock(&parent_inode->i_mutex);
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
 	if (sysfs_find_dirent(sd->s_parent, new_name))
 		goto out_unlock;
 
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(parent, new_name);
-	if (!new_dentry)
-		goto out_unlock;
-
 	/* rename sysfs_dirent */
 	error = -ENOMEM;
 	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
@@ -850,17 +920,21 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	sd->s_name = new_name;
 
 	/* rename */
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
+	list_for_each_entry(srs, &todo, list) {
+		d_add(srs->new_dentry, NULL);
+		d_move(srs->old_dentry, srs->new_dentry);
+	}
 
 	error = 0;
- out_unlock:
+out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&parent->d_inode->i_mutex);
+	mutex_unlock(&parent_inode->i_mutex);
 	kfree(dup_name);
-	dput(old_dentry);
-	dput(new_dentry);
- out:
+out_release:
+	iput(parent_inode);
+	post_rename(&todo);
+	sysfs_release_supers();
+out:
 	mutex_unlock(&sysfs_rename_mutex);
 	return error;
 }
@@ -869,10 +943,12 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 {
 	struct sysfs_dirent *sd = kobj->sd;
 	struct sysfs_dirent *new_parent_sd;
-	struct dentry *old_parent, *new_parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
+	struct list_head todo;
+	struct sysfs_rename_struct *srs;
+	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	int error;
 
+	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 	BUG_ON(!sd->s_parent);
 	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
@@ -881,26 +957,29 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 	if (sd->s_parent == new_parent_sd)
 		goto out;	/* nothing to move */
 
-	/* get dentries */
-	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
-	}
-	old_parent = old_dentry->d_parent;
+	sysfs_grab_supers();
+	error = prep_rename(&todo, sd, new_parent_sd, sd->s_name);
+	if (error)
+		goto out_release;
 
-	new_parent = sysfs_get_dentry(sysfs_sb, new_parent_sd);
-	if (IS_ERR(new_parent)) {
-		error = PTR_ERR(new_parent);
-		new_parent = NULL;
-		goto out;
-	}
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	old_parent_inode = sysfs_get_inode(sd->s_parent);
+	mutex_unlock(&sysfs_mutex);
+	if (!old_parent_inode)
+		goto out_release;
+
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	new_parent_inode = sysfs_get_inode(new_parent_sd);
+	mutex_unlock(&sysfs_mutex);
+	if (!new_parent_inode)
+		goto out_release;
 
 again:
-	mutex_lock(&old_parent->d_inode->i_mutex);
-	if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
-		mutex_unlock(&old_parent->d_inode->i_mutex);
+	mutex_lock(&old_parent_inode->i_mutex);
+	if (!mutex_trylock(&new_parent_inode->i_mutex)) {
+		mutex_unlock(&old_parent_inode->i_mutex);
 		goto again;
 	}
 	mutex_lock(&sysfs_mutex);
@@ -909,14 +988,11 @@ again:
 	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
 		goto out_unlock;
 
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(new_parent, sd->s_name);
-	if (!new_dentry)
-		goto out_unlock;
-
 	error = 0;
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
+	list_for_each_entry(srs, &todo, list) {
+		d_add(srs->new_dentry, NULL);
+		d_move(srs->old_dentry, srs->new_dentry);
+	}
 
 	/* Remove from old parent's list and insert into new parent's list. */
 	sysfs_unlink_sibling(sd);
@@ -925,14 +1001,17 @@ again:
 	sd->s_parent = new_parent_sd;
 	sysfs_link_sibling(sd);
 
- out_unlock:
+out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&new_parent->d_inode->i_mutex);
-	mutex_unlock(&old_parent->d_inode->i_mutex);
- out:
-	dput(new_parent);
-	dput(old_dentry);
-	dput(new_dentry);
+	mutex_unlock(&new_parent_inode->i_mutex);
+	mutex_unlock(&old_parent_inode->i_mutex);
+
+out_release:
+	iput(new_parent_inode);
+	iput(old_parent_inode);
+	post_rename(&todo);
+	sysfs_release_supers();
+out:
 	mutex_unlock(&sysfs_rename_mutex);
 	return error;
 }
-- 
1.5.3.rc6.17.g1911

[PATCH 06/15] Introduce sysfs_sd_setattr and fix sysfs_chmod

[Eric W. Biederman]

Currently sysfs_chmod calls sys_setattr which in turn calls
inode_change_ok which checks to see if it is ok for the current user
space process to change tha attributes. Since sysfs_chmod_file has
only kernel mode clients denying them permission if user space is the
problem is completely inappropriate.

Therefore factor out sysfs_sd_setattr which does not call
inode_change_ok and modify sysfs_chmod_file to call it.

In addition setting victim_sd->s_mode explicitly in sysfs_chmod_file
is redundant so remove that as well.

Thanks to Tejun Heo <htejun@gmail.com>, and
Daniel Lezcano <dlezcano@fr.ibm.com> for working on this
and spotting this case.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/file.c  |    5 +----
 fs/sysfs/inode.c |   23 ++++++++++++++++-------
 fs/sysfs/sysfs.h |    1 +
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index cb5dd3f..1304b3a 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -600,13 +600,10 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 	newattrs.ia_ctime = current_fs_time(inode->i_sb);
-	rc = sysfs_setattr(victim, &newattrs);
+	rc = sysfs_sd_setattr(victim_sd, inode, &newattrs);
 
 	if (rc == 0) {
 		fsnotify_change(victim, newattrs.ia_valid);
-		mutex_lock(&sysfs_mutex);
-		victim_sd->s_mode = newattrs.ia_mode;
-		mutex_unlock(&sysfs_mutex);
 	}
 
 	mutex_unlock(&inode->i_mutex);
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index eb53c63..80f8fd4 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -42,10 +42,9 @@ int __init sysfs_inode_init(void)
 	return bdi_init(&sysfs_backing_dev_info);
 }
 
-int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode,
+			struct iattr * iattr)
 {
-	struct inode * inode = dentry->d_inode;
-	struct sysfs_dirent * sd = dentry->d_fsdata;
 	struct iattr * sd_iattr;
 	unsigned int ia_valid = iattr->ia_valid;
 	int error;
@@ -55,10 +54,6 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
 
 	sd_iattr = sd->s_iattr;
 
-	error = inode_change_ok(inode, iattr);
-	if (error)
-		return error;
-
 	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
 
 	error = inode_setattr(inode, iattr);
@@ -104,6 +99,20 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
 	return error;
 }
 
+int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode * inode = dentry->d_inode;
+	struct sysfs_dirent * sd = dentry->d_fsdata;
+	int error;
+
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		return error;
+
+	return sysfs_sd_setattr(sd, inode, iattr);
+}
+
+
 static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
 {
 	inode->i_mode = mode;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index b1bdc6e..5ee5d0a 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -154,6 +154,7 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
  * inode.c
  */
 struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr);
 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
 int sysfs_inode_init(void);
-- 
1.5.3.rc6.17.g1911

[PATCH 07/15] sysfs: sysfs_chmod_file handle multiple superblocks

[Eric W. Biederman]

Teach sysfs_chmod_file how to handle multiple sysfs superblocks.
Since we only have one inode per sd the only thing we have to deal
with is multiple dentries for sending fs notifications.  This might
dup the inode notifications oh well.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/file.c |   39 +++++++++++++++++++++++++--------------
 1 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 1304b3a..5955ae9 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -574,8 +574,8 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
 int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 {
 	struct sysfs_dirent *victim_sd = NULL;
-	struct dentry *victim = NULL;
-	struct inode * inode;
+	struct super_block *sb;
+	struct inode * inode = NULL;
 	struct iattr newattrs;
 	int rc;
 
@@ -584,31 +584,42 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 	if (!victim_sd)
 		goto out;
 
-	mutex_lock(&sysfs_rename_mutex);
-	victim = sysfs_get_dentry(sysfs_sb, victim_sd);
-	mutex_unlock(&sysfs_rename_mutex);
-	if (IS_ERR(victim)) {
-		rc = PTR_ERR(victim);
-		victim = NULL;
-		goto out;
-	}
-
-	inode = victim->d_inode;
+	rc = -ENOENT;
+	mutex_lock(&sysfs_mutex);
+	inode = sysfs_get_inode(victim_sd);
+	mutex_unlock(&sysfs_mutex);
+	if (!inode)
+ 		goto out;
 
+	mutex_lock(&sysfs_rename_mutex);
+	sysfs_grab_supers();
 	mutex_lock(&inode->i_mutex);
 
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 	newattrs.ia_ctime = current_fs_time(inode->i_sb);
 	rc = sysfs_sd_setattr(victim_sd, inode, &newattrs);
+	if (rc)
+		goto out_unlock;
+
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		/* Ignore it when the dentry does not exist on the
+		 * target superblock.
+		 */
+		struct dentry *	victim = sysfs_get_dentry(sb, victim_sd);
+		if (IS_ERR(victim))
+			continue;
 
-	if (rc == 0) {
 		fsnotify_change(victim, newattrs.ia_valid);
+		dput(victim);
 	}
 
+ out_unlock:
 	mutex_unlock(&inode->i_mutex);
+	sysfs_release_supers();
+	mutex_unlock(&sysfs_rename_mutex);
  out:
-	dput(victim);
+	iput(inode);
 	sysfs_put(victim_sd);
 	return rc;
 }
-- 
1.5.3.rc6.17.g1911

[PATCH 08/15] sysfs: Make sysfs_mount static once again.

[Eric W. Biederman]

Accessing the internal sysfs_mount is error prone in the context
of multiple super blocks, and nothing needs it.  Not even the
sysfs crash debugging patch (although it did in an earlier version).

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/mount.c |    2 +-
 fs/sysfs/sysfs.h |    1 -
 2 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index c812cc4..99974f0 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -22,7 +22,7 @@
 /* Random magic number */
 #define SYSFS_MAGIC 0x62656572
 
-struct vfsmount *sysfs_mount;
+static struct vfsmount *sysfs_mount;
 struct super_block * sysfs_sb = NULL;
 struct kmem_cache *sysfs_dir_cachep;
 
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 5ee5d0a..33b3c73 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -97,7 +97,6 @@ struct sysfs_super_info {
 extern struct sysfs_dirent sysfs_root;
 extern struct super_block *sysfs_sb;
 extern struct kmem_cache *sysfs_dir_cachep;
-extern struct vfsmount *sysfs_mount;
 extern struct file_system_type sysfs_fs_type;
 
 void sysfs_grab_supers(void);
-- 
1.5.3.rc6.17.g1911

[PATCH 09/15] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

The problem.  When implementing a network namespace I need to be able
to have multiple network devices with the same name.  Currently this
is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
potentially a few other directories of the form /sys/ ... /net/*.

What this patch does is to add an additional tag field to the
sysfs dirent structure.  For directories that should show different
contents depending on the context such as /sys/class/net/, and
/sys/devices/virtual/net/ this tag field is used to specify the
context in which those directories should be visible.  Effectively
this is the same as creating multiple distinct directories with
the same name but internally to sysfs the result is nicer.

I am calling the concept of a single directory that looks like multiple
directories all at the same path in the filesystem tagged directories.

For the networking namespace the set of directories whose contents I need
to filter with tags can depend on the presence or absence of hotplug
hardware or which modules are currently loaded.  Which means I need
a simple race free way to setup those directories as tagged.

To achieve a reace free design all tagged directories are created and
managed by sysfs itself.

Users of this interface:
- define a type in the sysfs_tag_type enumeration.
- call sysfs_register_tag_types with the type and it's operations
- call sysfs_make_tagged_dir with the tag type on directories
  to be managed by this tag type
- sysfs_exit_tag when an individual tag is no longer valid

- Implement mount_tag() which returns the tag of the calling process
  so we can attach it to a sysfs superblock.
- Implement ktype.sysfs_tag() which returns the tag of a syfs kobject.

Everything else is left up to sysfs and the driver layer.

For the network namespace mount_tag and sysfs_tag are essentially
one line functions, and look to remain that.

Tags are currently represented a const void * pointers as that is
both generic, prevides enough information for equality comparisons,
and is trivial to create for current users, as it is just the
existing namespace pointer.

The work needed in sysfs is more extensive.  At each directory
or symlink creating I need to check if the directory it is being
created in is a tagged directory and if so generate the appropriate
tag to place on the sysfs_dirent.  Likewise at each symlink or
directory removal I need to check if the sysfs directory it is
being removed from is a tagged directory and if so figure out
which tag goes along with the name I am deleting.

Currently only directories which hold kobjects, and
symlinks are supported.  There is not enough information
in the current file attribute interfaces to give us anything
to discriminate on which makes it useless, and there are
no potential users which makes it an uninteresting problem
to solve.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
---
 fs/sysfs/bin.c          |    2 +-
 fs/sysfs/dir.c          |  139 ++++++++++++++++++++++++++++++++++++++++++-----
 fs/sysfs/file.c         |   10 ++--
 fs/sysfs/group.c        |    4 +-
 fs/sysfs/inode.c        |    7 ++-
 fs/sysfs/mount.c        |  115 +++++++++++++++++++++++++++++++++++++--
 fs/sysfs/symlink.c      |    2 +-
 fs/sysfs/sysfs.h        |   19 ++++++-
 include/linux/kobject.h |    1 +
 include/linux/sysfs.h   |   29 ++++++++++
 10 files changed, 295 insertions(+), 33 deletions(-)

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index 006fc64..86e1128 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -252,7 +252,7 @@ int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 
 void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 {
-	sysfs_hash_and_remove(kobj->sd, attr->attr.name);
+	sysfs_hash_and_remove(kobj, kobj->sd, attr->attr.name);
 }
 
 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index b2d92ea..6dc3376 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -30,6 +30,30 @@ DEFINE_SPINLOCK(sysfs_assoc_lock);
 static DEFINE_SPINLOCK(sysfs_ino_lock);
 static DEFINE_IDA(sysfs_ino_ida);
 
+static const void *sysfs_creation_tag(struct sysfs_dirent *parent_sd,
+				      struct sysfs_dirent *sd)
+{
+	const void *tag = NULL;
+
+	if (sysfs_tag_type(parent_sd)) {
+		struct kobject *kobj;
+		switch (sysfs_type(sd)) {
+		case SYSFS_DIR:
+			kobj = sd->s_dir.kobj;
+			break;
+		case SYSFS_KOBJ_LINK:
+			kobj = sd->s_symlink.target_sd->s_dir.kobj;
+			break;
+		default:
+			BUG();
+		}
+		tag = kobj->ktype->sysfs_tag(kobj);
+		/* NULL tags are reserved for internal use */
+		BUG_ON(tag == NULL);
+	}
+	return tag;
+}
+
 /**
  *	sysfs_link_sibling - link sysfs_dirent into sibling list
  *	@sd: sysfs_dirent of interest
@@ -101,8 +125,19 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
 struct dentry *sysfs_get_dentry(struct super_block *sb,
 				struct sysfs_dirent *sd)
 {
-	struct dentry *dentry = dget(sb->s_root);
+	struct dentry *dentry;
+
+	/* Bail if this sd won't show up in this superblock */
+	if (sd->s_parent) {
+		enum sysfs_tag_type type;
+		const void *tag;
+		type = sysfs_tag_type(sd->s_parent);
+		tag = sysfs_info(sb)->tag[type];
+		if (sd->s_tag != tag)
+			return ERR_PTR(-EXDEV);
+	}
 
+	dentry = dget(sb->s_root);
 	while (dentry->d_fsdata != sd) {
 		struct sysfs_dirent *cur;
 		struct dentry *parent;
@@ -421,10 +456,15 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
  */
 int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
 {
-	if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
+	const void *tag = NULL;
+
+	tag = sysfs_creation_tag(acxt->parent_sd, sd);
+
+	if (sysfs_find_dirent(acxt->parent_sd, tag, sd->s_name))
 		return -EEXIST;
 
 	sd->s_parent = sysfs_get(acxt->parent_sd);
+	sd->s_tag = tag;
 
 	if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
 		inc_nlink(acxt->parent_inode);
@@ -572,13 +612,17 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
  *	Pointer to sysfs_dirent if found, NULL if not.
  */
 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
+				       const void *tag,
 				       const unsigned char *name)
 {
 	struct sysfs_dirent *sd;
 
-	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
+	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
+		if (sd->s_tag != tag)
+			continue;
 		if (!strcmp(sd->s_name, name))
 			return sd;
+	}
 	return NULL;
 }
 
@@ -602,7 +646,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 	struct sysfs_dirent *sd;
 
 	mutex_lock(&sysfs_mutex);
-	sd = sysfs_find_dirent(parent_sd, name);
+	sd = sysfs_find_dirent(parent_sd, NULL, name);
 	sysfs_get(sd);
 	mutex_unlock(&sysfs_mutex);
 
@@ -668,13 +712,18 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
 				struct nameidata *nd)
 {
 	struct dentry *ret = NULL;
-	struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
+	struct dentry *parent = dentry->d_parent;
+	struct sysfs_dirent *parent_sd = parent->d_fsdata;
 	struct sysfs_dirent *sd;
 	struct inode *inode;
+	enum sysfs_tag_type type;
+	const void *tag;
 
 	mutex_lock(&sysfs_mutex);
 
-	sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
+	type = sysfs_tag_type(parent_sd);
+	tag = sysfs_info(parent->d_sb)->tag[type];
+	sd = sysfs_find_dirent(parent_sd, tag, dentry->d_name.name);
 
 	/* no such entry */
 	if (!sd) {
@@ -882,19 +931,24 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	struct sysfs_rename_struct *srs;
 	struct inode *parent_inode = NULL;
 	const char *dup_name = NULL;
+	const void *old_tag, *tag;
 	int error;
 
 	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
+	old_tag = sd->s_tag;
+	tag = sysfs_creation_tag(sd->s_parent, sd);
 
 	error = 0;
-	if (strcmp(sd->s_name, new_name) == 0)
+	if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
 		goto out;	/* nothing to rename */
 
 	sysfs_grab_supers();
-	error = prep_rename(&todo, sd, sd->s_parent, new_name);
-	if (error)
-		goto out_release;
+	if (old_tag == tag) {
+		error = prep_rename(&todo, sd, sd->s_parent, new_name);
+		if (error)
+			goto out_release;
+	}
 
 	error = -ENOMEM;
 	mutex_lock(&sysfs_mutex);
@@ -907,7 +961,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(sd->s_parent, new_name))
+	if (sysfs_find_dirent(sd->s_parent, tag, new_name))
 		goto out_unlock;
 
 	/* rename sysfs_dirent */
@@ -918,6 +972,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 
 	dup_name = sd->s_name;
 	sd->s_name = new_name;
+	sd->s_tag = tag;
 
 	/* rename */
 	list_for_each_entry(srs, &todo, list) {
@@ -925,6 +980,20 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 		d_move(srs->old_dentry, srs->new_dentry);
 	}
 
+	/* If we are moving across superblocks drop the dcache entries */
+	if (old_tag != tag) {
+		struct super_block *sb;
+		struct dentry *dentry;
+		list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+			dentry = __sysfs_get_dentry(sb, sd);
+			if (!dentry)
+				continue;
+			shrink_dcache_parent(dentry);
+			d_drop(dentry);
+			dput(dentry);
+		}
+	}
+
 	error = 0;
 out_unlock:
 	mutex_unlock(&sysfs_mutex);
@@ -947,11 +1016,13 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 	struct sysfs_rename_struct *srs;
 	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	int error;
+	const void *tag;
 
 	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 	BUG_ON(!sd->s_parent);
 	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
+	tag = sd->s_tag;
 
 	error = 0;
 	if (sd->s_parent == new_parent_sd)
@@ -985,7 +1056,7 @@ again:
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
+	if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
 		goto out_unlock;
 
 	error = 0;
@@ -1024,10 +1095,12 @@ static inline unsigned char dt_type(struct sysfs_dirent *sd)
 
 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
-	struct dentry *dentry = filp->f_path.dentry;
-	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
+	struct dentry *parent = filp->f_path.dentry;
+	struct sysfs_dirent *parent_sd = parent->d_fsdata;
 	struct sysfs_dirent *pos;
 	ino_t ino;
+	enum sysfs_tag_type type;
+	const void *tag;
 
 	if (filp->f_pos == 0) {
 		ino = parent_sd->s_ino;
@@ -1045,6 +1118,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 	if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
 		mutex_lock(&sysfs_mutex);
 
+		type = sysfs_tag_type(parent_sd);
+		tag = sysfs_info(parent->d_sb)->tag[type];
+
 		/* Skip the dentries we have already reported */
 		pos = parent_sd->s_dir.children;
 		while (pos && (filp->f_pos > pos->s_ino))
@@ -1054,6 +1130,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 			const char * name;
 			int len;
 
+			if (pos->s_tag != tag)
+				continue;
+
 			name = pos->s_name;
 			len = strlen(name);
 			filp->f_pos = ino = pos->s_ino;
@@ -1074,3 +1153,35 @@ const struct file_operations sysfs_dir_operations = {
 	.read		= generic_read_dir,
 	.readdir	= sysfs_readdir,
 };
+
+/**
+ *	sysfs_make_tagged_dir - Require tags of all the entries in a directory.
+ *	@kobj:	object whose children should be filtered by tags
+ *
+ *	Once tagging has been enabled on a directory the contents
+ *	of the directory become dependent upon context captured when
+ *	sysfs was mounted.
+ */
+int sysfs_make_tagged_dir(struct kobject *kobj, enum sysfs_tag_type type)
+{
+	struct sysfs_dirent *sd;
+	int err;
+
+	err = -ENOENT;
+	sd = kobj->sd;
+
+	mutex_lock(&sysfs_mutex);
+	err = -EINVAL;
+	/* We can only enable tagging when we have a valid tag type
+	 * on empty directories where taggint has not already been
+	 * enabled.
+	 */
+	if ((type > SYSFS_TAG_TYPE_NONE) && (type < SYSFS_TAG_TYPES) &&
+	    tag_ops[type] && !sysfs_tag_type(sd) &&
+	    (sysfs_type(sd) == SYSFS_DIR) && !sd->s_dir.children) {
+		err = 0;
+		sd->s_flags |= (type << SYSFS_TAG_TYPE_SHIFT);
+	}
+	mutex_unlock(&sysfs_mutex);
+	return err;
+}
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 5955ae9..be95fa2 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -461,9 +461,11 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
 	mutex_lock(&sysfs_mutex);
 
 	if (sd && dir)
-		sd = sysfs_find_dirent(sd, dir);
+		/* only directories are tagged, so no need to pass
+		 a tag explicitly */
+		sd = sysfs_find_dirent(sd, NULL, dir);
 	if (sd && attr)
-		sd = sysfs_find_dirent(sd, attr);
+		sd = sysfs_find_dirent(sd, NULL, attr);
 	if (sd) {
 		struct sysfs_open_dirent *od;
 
@@ -636,7 +638,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file);
 
 void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
 {
-	sysfs_hash_and_remove(kobj->sd, attr->name);
+	sysfs_hash_and_remove(kobj, kobj->sd, attr->name);
 }
 
 
@@ -656,7 +658,7 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
 	else
 		dir_sd = sysfs_get(kobj->sd);
 	if (dir_sd) {
-		sysfs_hash_and_remove(dir_sd, attr->name);
+		sysfs_hash_and_remove(kobj, dir_sd, attr->name);
 		sysfs_put(dir_sd);
 	}
 }
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index eeba384..b6693b4 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -23,7 +23,7 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 	int i;
 
 	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
-		sysfs_hash_and_remove(dir_sd, (*attr)->name);
+		sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
 }
 
 static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
@@ -39,7 +39,7 @@ static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 		 * visibility.  Do this by first removing then
 		 * re-adding (if required) the file */
 		if (update)
-			sysfs_hash_and_remove(dir_sd, (*attr)->name);
+			sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
 		if (grp->is_visible) {
 			mode = grp->is_visible(kobj, *attr, i);
 			if (!mode)
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 80f8fd4..b5fc78a 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -226,17 +226,20 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
 	return inode;
 }
 
-int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
+int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
+			  const char *name)
 {
 	struct sysfs_addrm_cxt acxt;
 	struct sysfs_dirent *sd;
+	const void *tag;
 
 	if (!dir_sd)
 		return -ENOENT;
 
 	sysfs_addrm_start(&acxt, dir_sd);
+	tag = kobj->sd->s_tag;
 
-	sd = sysfs_find_dirent(dir_sd, name);
+	sd = sysfs_find_dirent(dir_sd, tag, name);
 	if (sd)
 		sysfs_remove_one(&acxt, sd);
 
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 99974f0..c4a3022 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -34,12 +34,15 @@ static const struct super_operations sysfs_ops = {
 struct sysfs_dirent sysfs_root = {
 	.s_name		= "",
 	.s_count	= ATOMIC_INIT(1),
-	.s_flags	= SYSFS_DIR,
+	.s_flags	= SYSFS_DIR | (SYSFS_TAG_TYPE_NONE << SYSFS_TAG_TYPE_SHIFT),
 	.s_mode		= S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
 	.s_ino		= 1,
 };
 
-static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
+struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
+
+static int sysfs_fill_super(struct super_block *sb, void *data, int silent,
+	const void *tags[SYSFS_TAG_TYPES])
 {
 	struct sysfs_super_info *info = NULL;
 	struct inode *inode = NULL;
@@ -75,8 +78,10 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_err;
 	}
 	root->d_fsdata = &sysfs_root;
+	root->d_sb = sb;
 	sb->s_root = root;
 	sb->s_fs_info = info;
+	memcpy(info->tag, tags, sizeof(info->tag[0])*SYSFS_TAG_TYPES);
 	return 0;
 
 out_err:
@@ -88,20 +93,74 @@ out_err:
 	return error;
 }
 
+static int sysfs_test_super(struct super_block *sb, void *ptr)
+{
+	const void **tag = ptr;
+	struct sysfs_super_info *info = sysfs_info(sb);
+	enum sysfs_tag_type type;
+	int found = 1;
+
+	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
+		if (info->tag[type] != tag[type]) {
+			found = 0;
+			break;
+		}
+	}
+
+	return found;
+}
+
 static int sysfs_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
-	int rc;
+	const void *tag[SYSFS_TAG_TYPES];
+	struct super_block *sb;
+	int error;
+	enum sysfs_tag_type type;
+
+	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
+		tag[type] = NULL;
+		if (!tag_ops[type])
+			continue;
+		tag[type] = tag_ops[type]->mount_tag();
+	}
+
 	mutex_lock(&sysfs_rename_mutex);
-	rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
+	sb = sget(fs_type, sysfs_test_super, set_anon_super, tag);
+	if (IS_ERR(sb)) {
+		error = PTR_ERR(sb);
+		goto out;
+	}
+	if (!sb->s_root) {
+		sb->s_flags = flags;
+		error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0,
+					tag);
+		if (error) {
+			up_write(&sb->s_umount);
+			deactivate_super(sb);
+			goto out;
+		}
+		sb->s_flags |= MS_ACTIVE;
+	}
+	do_remount_sb(sb, flags, data, 0);
+	error = simple_set_mnt(mnt, sb);
+out:
 	mutex_unlock(&sysfs_rename_mutex);
-	return rc;
+	return error;
+}
+
+static void sysfs_kill_sb(struct super_block *sb)
+{
+	struct sysfs_super_info *info = sysfs_info(sb);
+
+	kill_anon_super(sb);
+	kfree(info);
 }
 
 struct file_system_type sysfs_fs_type = {
 	.name		= "sysfs",
 	.get_sb		= sysfs_get_sb,
-	.kill_sb	= kill_anon_super,
+	.kill_sb	= sysfs_kill_sb,
 };
 
 void sysfs_grab_supers(void)
@@ -145,6 +204,50 @@ restart:
 	spin_unlock(&sb_lock);
 }
 
+int sysfs_register_tag_type(enum sysfs_tag_type type, struct sysfs_tag_type_operations *ops)
+{
+	int error;
+
+	mutex_lock(&sysfs_rename_mutex);
+
+	error = -EINVAL;
+	if (type >= SYSFS_TAG_TYPES)
+		goto out;
+
+	error = -EINVAL;
+	if (type <= SYSFS_TAG_TYPE_NONE)
+		goto out;
+
+	error = -EBUSY;
+	if (tag_ops[type])
+		goto out;
+
+	error = 0;
+	tag_ops[type] = ops;
+
+out:
+	mutex_unlock(&sysfs_rename_mutex);
+	return error;
+}
+
+void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
+{
+	/* Allow the tag to go away while sysfs is still mounted. */
+	struct super_block *sb;
+	mutex_lock(&sysfs_rename_mutex);
+	sysfs_grab_supers();
+	mutex_lock(&sysfs_mutex);
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		struct sysfs_super_info *info = sysfs_info(sb);
+		if (info->tag[type] != tag)
+			continue;
+		info->tag[type] = NULL;
+	}
+	mutex_unlock(&sysfs_mutex);
+	sysfs_release_supers();
+	mutex_unlock(&sysfs_rename_mutex);
+}
+
 int __init sysfs_init(void)
 {
 	int err = -ENOMEM;
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 817f596..de9a5c0 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -94,7 +94,7 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
 	else
 		parent_sd = kobj->sd;
 
-	sysfs_hash_and_remove(parent_sd, name);
+	sysfs_hash_and_remove(kobj, parent_sd, name);
 }
 
 static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 33b3c73..4128e6f 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -45,6 +45,7 @@ struct sysfs_dirent {
 	struct sysfs_dirent	*s_sibling;
 	const char		*s_name;
 
+	const void		*s_tag;
 	union {
 		struct sysfs_elem_dir		s_dir;
 		struct sysfs_elem_symlink	s_symlink;
@@ -67,14 +68,22 @@ struct sysfs_dirent {
 #define SYSFS_KOBJ_LINK			0x0008
 #define SYSFS_COPY_NAME			(SYSFS_DIR | SYSFS_KOBJ_LINK)
 
-#define SYSFS_FLAG_MASK			~SYSFS_TYPE_MASK
-#define SYSFS_FLAG_REMOVED		0x0200
+#define SYSFS_TAG_TYPE_MASK		0xff00
+#define SYSFS_TAG_TYPE_SHIFT		8
+
+#define SYSFS_FLAG_MASK			~(SYSFS_TYPE_MASK | SYSFS_TAG_TYPE_MASK)
+#define SYSFS_FLAG_REMOVED		0x020000
 
 static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
 {
 	return sd->s_flags & SYSFS_TYPE_MASK;
 }
 
+static inline enum sysfs_tag_type sysfs_tag_type(struct sysfs_dirent *sd)
+{
+	return (sd->s_flags & SYSFS_TAG_TYPE_MASK) >> SYSFS_TAG_TYPE_SHIFT;
+}
+
 /*
  * Context structure to be used while adding/removing nodes.
  */
@@ -87,6 +96,7 @@ struct sysfs_addrm_cxt {
 
 struct sysfs_super_info {
 	int	grabbed;
+	const void *tag[SYSFS_TAG_TYPES];
 };
 
 #define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
@@ -98,6 +108,7 @@ extern struct sysfs_dirent sysfs_root;
 extern struct super_block *sysfs_sb;
 extern struct kmem_cache *sysfs_dir_cachep;
 extern struct file_system_type sysfs_fs_type;
+extern struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
 
 void sysfs_grab_supers(void);
 void sysfs_release_supers(void);
@@ -123,6 +134,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
 
 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
+				       const void *tag,
 				       const unsigned char *name);
 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 				      const unsigned char *name);
@@ -155,7 +167,8 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
 struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
 int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr);
 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
-int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
+int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
+			  const char *name);
 int sysfs_inode_init(void);
 
 /*
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 60f0d41..6bc38f8 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -105,6 +105,7 @@ struct kobj_type {
 	void (*release)(struct kobject *kobj);
 	struct sysfs_ops *sysfs_ops;
 	struct attribute **default_attrs;
+	const void *(*sysfs_tag)(struct kobject *kobj);
 };
 
 struct kobj_uevent_env {
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index f7e43ed..8fa97f0 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -78,6 +78,15 @@ struct sysfs_ops {
 	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t);
 };
 
+enum sysfs_tag_type {
+	SYSFS_TAG_TYPE_NONE = 0,
+	SYSFS_TAG_TYPES
+};
+
+struct sysfs_tag_type_operations {
+	const void *(*mount_tag)(void);
+};
+
 #ifdef CONFIG_SYSFS
 
 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
@@ -117,6 +126,10 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
 void sysfs_notify(struct kobject *kobj, char *dir, char *attr);
 void sysfs_printk_last_file(void);
 
+int sysfs_make_tagged_dir(struct kobject *, enum sysfs_tag_type tag_type);
+int sysfs_register_tag_type(enum sysfs_tag_type type, struct sysfs_tag_type_operations *ops);
+void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag);
+
 extern int __must_check sysfs_init(void);
 
 #else /* CONFIG_SYSFS */
@@ -217,6 +230,22 @@ static inline void sysfs_notify(struct kobject *kobj, char *dir, char *attr)
 {
 }
 
+staticn inline int sysfs_make_tagged_dir(struct kobject *kobj,
+						enum sysfs_tag_type tag_type)
+{
+	return 0;
+}
+
+static inline int sysfs_register_tag_type(enum sysfs_tag_type type,
+					struct sysfs_tag_type_operations *ops)
+{
+	return 0;
+}
+
+static inline void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
+{
+}
+
 static inline int __must_check sysfs_init(void)
 {
 	return 0;
-- 
1.5.3.rc6.17.g1911

[PATCH 10/15] sysfs: Merge sysfs_rename_dir and sysfs_move_dir

[Eric W. Biederman]

These two functions do 90% of the same work and it doesn't
significantly obfuscate the function to allow both the parent dir and
the name to change at the same time.  So merge them together to
simplify maintenance, and increase testing.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/dir.c |  121 +++++++++++++++++--------------------------------------
 1 files changed, 38 insertions(+), 83 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 6dc3376..fe2bb1c 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -924,44 +924,57 @@ err_out:
 	return error;
 }
 
-int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
+static int sysfs_mv_dir(struct sysfs_dirent *sd,
+	struct sysfs_dirent *new_parent_sd, const char *new_name)
 {
-	struct sysfs_dirent *sd = kobj->sd;
 	struct list_head todo;
 	struct sysfs_rename_struct *srs;
-	struct inode *parent_inode = NULL;
+	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	const char *dup_name = NULL;
 	const void *old_tag, *tag;
 	int error;
 
 	INIT_LIST_HEAD(&todo);
+	BUG_ON(!sd->s_parent);
 	mutex_lock(&sysfs_rename_mutex);
+	if (!new_parent_sd)
+		new_parent_sd = &sysfs_root;
+
 	old_tag = sd->s_tag;
 	tag = sysfs_creation_tag(sd->s_parent, sd);
 
 	error = 0;
-	if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
-		goto out;	/* nothing to rename */
+	if ((sd->s_parent == new_parent_sd) && (old_tag == tag) &&
+	    (strcmp(sd->s_name, new_name) == 0))
+		goto out;	/* nothing to do */
 
 	sysfs_grab_supers();
 	if (old_tag == tag) {
-		error = prep_rename(&todo, sd, sd->s_parent, new_name);
+		error = prep_rename(&todo, sd, new_parent_sd, new_name);
 		if (error)
 			goto out_release;
 	}
 
 	error = -ENOMEM;
 	mutex_lock(&sysfs_mutex);
-	parent_inode = sysfs_get_inode(sd->s_parent);
+	old_parent_inode = sysfs_get_inode(sd->s_parent);
+	new_parent_inode = sysfs_get_inode(new_parent_sd);
 	mutex_unlock(&sysfs_mutex);
-	if (!parent_inode)
+	if (!old_parent_inode || !new_parent_inode)
 		goto out_release;
 
-	mutex_lock(&parent_inode->i_mutex);
+again:
+	mutex_lock(&old_parent_inode->i_mutex);
+	if (old_parent_inode != new_parent_inode) {
+		if (!mutex_trylock(&new_parent_inode->i_mutex)) {
+			mutex_unlock(&old_parent_inode->i_mutex);
+			goto again;
+		}
+	}
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(sd->s_parent, tag, new_name))
+	if (sysfs_find_dirent(new_parent_sd, tag, new_name))
 		goto out_unlock;
 
 	/* rename sysfs_dirent */
@@ -974,7 +987,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	sd->s_name = new_name;
 	sd->s_tag = tag;
 
-	/* rename */
+	/* rename dcache entries */
 	list_for_each_entry(srs, &todo, list) {
 		d_add(srs->new_dentry, NULL);
 		d_move(srs->old_dentry, srs->new_dentry);
@@ -994,77 +1007,6 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 		}
 	}
 
-	error = 0;
-out_unlock:
-	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&parent_inode->i_mutex);
-	kfree(dup_name);
-out_release:
-	iput(parent_inode);
-	post_rename(&todo);
-	sysfs_release_supers();
-out:
-	mutex_unlock(&sysfs_rename_mutex);
-	return error;
-}
-
-int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
-{
-	struct sysfs_dirent *sd = kobj->sd;
-	struct sysfs_dirent *new_parent_sd;
-	struct list_head todo;
-	struct sysfs_rename_struct *srs;
-	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
-	int error;
-	const void *tag;
-
-	INIT_LIST_HEAD(&todo);
-	mutex_lock(&sysfs_rename_mutex);
-	BUG_ON(!sd->s_parent);
-	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
-	tag = sd->s_tag;
-
-	error = 0;
-	if (sd->s_parent == new_parent_sd)
-		goto out;	/* nothing to move */
-
-	sysfs_grab_supers();
-	error = prep_rename(&todo, sd, new_parent_sd, sd->s_name);
-	if (error)
-		goto out_release;
-
-	error = -ENOMEM;
-	mutex_lock(&sysfs_mutex);
-	old_parent_inode = sysfs_get_inode(sd->s_parent);
-	mutex_unlock(&sysfs_mutex);
-	if (!old_parent_inode)
-		goto out_release;
-
-	error = -ENOMEM;
-	mutex_lock(&sysfs_mutex);
-	new_parent_inode = sysfs_get_inode(new_parent_sd);
-	mutex_unlock(&sysfs_mutex);
-	if (!new_parent_inode)
-		goto out_release;
-
-again:
-	mutex_lock(&old_parent_inode->i_mutex);
-	if (!mutex_trylock(&new_parent_inode->i_mutex)) {
-		mutex_unlock(&old_parent_inode->i_mutex);
-		goto again;
-	}
-	mutex_lock(&sysfs_mutex);
-
-	error = -EEXIST;
-	if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
-		goto out_unlock;
-
-	error = 0;
-	list_for_each_entry(srs, &todo, list) {
-		d_add(srs->new_dentry, NULL);
-		d_move(srs->old_dentry, srs->new_dentry);
-	}
-
 	/* Remove from old parent's list and insert into new parent's list. */
 	sysfs_unlink_sibling(sd);
 	sysfs_get(new_parent_sd);
@@ -1072,10 +1014,13 @@ again:
 	sd->s_parent = new_parent_sd;
 	sysfs_link_sibling(sd);
 
+	error = 0;
 out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&new_parent_inode->i_mutex);
+	if (new_parent_inode != old_parent_inode)
+		mutex_unlock(&new_parent_inode->i_mutex);
 	mutex_unlock(&old_parent_inode->i_mutex);
+	kfree(dup_name);
 
 out_release:
 	iput(new_parent_inode);
@@ -1087,6 +1032,16 @@ out:
 	return error;
 }
 
+int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
+{
+	return sysfs_mv_dir(kobj->sd, kobj->sd->s_parent, new_name);
+}
+
+int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
+{
+	return sysfs_mv_dir(kobj->sd, new_parent_kobj->sd, kobj->sd->s_name);
+}
+
 /* Relationship between s_mode and the DT_xxx types */
 static inline unsigned char dt_type(struct sysfs_dirent *sd)
 {
-- 
1.5.3.rc6.17.g1911

[PATCH 11/15] sysfs: Implement sysfs_delete_link and sysfs_rename_link

[Eric W. Biederman]

When removing a symlink sysfs_remove_link does not provide
enough information to figure out which tagged directory the symlink
falls in.  So I need sysfs_delete_link which is passed the target
of the symlink to delete.

Further half the time when we are removing a symlink the code is
actually renaming the symlink but not doing so explicitly because
we don't have a symlink rename method. So I have added sysfs_rename_link
as well.

Both of these functions now have enough information to find a symlink
in a tagged directory.  The only restriction is that they must be called
before the target kobject is renamed or deleted.  If they are called
later I loose track of which tag the target kobject was marked with
and can no longer find the old symlink to remove it.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/symlink.c    |   31 +++++++++++++++++++++++++++++++
 include/linux/sysfs.h |   17 +++++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index de9a5c0..ed9c52c 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -80,6 +80,21 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 }
 
 /**
+ *	sysfs_delete_link - remove symlink in object's directory.
+ *	@kobj:	object we're acting for.
+ *	@targ:	object we're pointing to.
+ *	@name:	name of the symlink to remove.
+ *
+ *	Unlike sysfs_remove_link sysfs_delete_link has enough information
+ *	to successfully delete symlinks in tagged directories.
+ */
+void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
+			const char *name)
+{
+	sysfs_hash_and_remove(targ, kobj->sd, name);
+}
+
+/**
  *	sysfs_remove_link - remove symlink in object's directory.
  *	@kobj:	object we're acting for.
  *	@name:	name of the symlink to remove.
@@ -97,6 +112,22 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
 	sysfs_hash_and_remove(kobj, parent_sd, name);
 }
 
+/**
+ *	sysfs_rename_link - rename symlink in object's directory.
+ *	@kobj:	object we're acting for.
+ *	@targ:	object we're pointing to.
+ *	@old:	previous name of the symlink.
+ *	@new:	new name of the symlink.
+ *
+ *	A helper function for the common rename symlink idiom.
+ */
+int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
+			const char *old, const char *new)
+{
+	sysfs_delete_link(kobj, targ, old);
+	return sysfs_create_link(kobj, targ, new);
+}
+
 static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
 				 struct sysfs_dirent *target_sd, char *path)
 {
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 8fa97f0..c3a30ce 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -112,6 +112,12 @@ int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
 				   const char *name);
 void sysfs_remove_link(struct kobject *kobj, const char *name);
 
+int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
+			const char *old_name, const char *new_name);
+
+void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
+			const char *name);
+
 int __must_check sysfs_create_group(struct kobject *kobj,
 				    const struct attribute_group *grp);
 int sysfs_update_group(struct kobject *kobj,
@@ -198,6 +204,17 @@ static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
 {
 }
 
+static inline int sysfs_rename_link(struct kobject *k, struct kobject *t,
+				    const char *old_name, const char *new_name)
+{
+	return 0;
+}
+
+static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
+				     const char *name)
+{
+}
+
 static inline int sysfs_create_group(struct kobject *kobj,
 				     const struct attribute_group *grp)
 {
-- 
1.5.3.rc6.17.g1911

[PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

This patch enables tagging on every class directory if struct class
has a tag_type.

In addition device_del and device_rename were modified to uses
sysfs_delete_link and sysfs_rename_link respectively to ensure
when these operations happen on devices whose classes have
tag_ops that they work properly.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
---
 drivers/base/class.c   |   30 ++++++++++++++++++++++---
 drivers/base/core.c    |   56 +++++++++++++++++++++++++++++++++--------------
 include/linux/device.h |    3 ++
 3 files changed, 68 insertions(+), 21 deletions(-)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 839d27c..cf4e03f 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -135,6 +135,17 @@ static void remove_class_attrs(struct class *cls)
 	}
 }
 
+static int class_setup_tagging(struct class *cls)
+{
+	enum sysfs_tag_type type;
+
+	type = cls->tag_type;
+	if (type == SYSFS_TAG_TYPE_NONE)
+		return 0;
+
+	return sysfs_make_tagged_dir(&cls->p->class_subsys.kobj, type);
+}
+
 int __class_register(struct class *cls, struct lock_class_key *key)
 {
 	struct class_private *cp;
@@ -171,13 +182,24 @@ int __class_register(struct class *cls, struct lock_class_key *key)
 	cls->p = cp;
 
 	error = kset_register(&cp->class_subsys);
-	if (error) {
-		kfree(cp);
-		return error;
-	}
+	if (error)
+		goto out_free_cp;
+
+	error = class_setup_tagging(cls);
+	if (error)
+		goto out_unregister;
+
 	error = add_class_attrs(class_get(cls));
 	class_put(cls);
+	if (error)
+		goto out_unregister;
+out:
 	return error;
+out_unregister:
+	kset_unregister(&cp->class_subsys);
+out_free_cp:
+	kfree(cp);
+	goto out;
 }
 EXPORT_SYMBOL_GPL(__class_register);
 
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 90621a4..b009d5b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -124,9 +124,21 @@ static void device_release(struct kobject *kobj)
 	}
 }
 
+static const void *device_sysfs_tag(struct kobject *kobj)
+{
+	struct device *dev = to_dev(kobj);
+	const void *tag = NULL;
+
+	if (dev->class && dev->class->tag_type)
+		tag = dev->class->sysfs_tag(dev);
+
+	return tag;
+}
+
 static struct kobj_type device_ktype = {
 	.release	= device_release,
 	.sysfs_ops	= &dev_sysfs_ops,
+	.sysfs_tag	= device_sysfs_tag,
 };
 
 
@@ -619,6 +631,10 @@ static struct kobject *get_device_parent(struct device *dev,
 			kobject_put(k);
 			return NULL;
 		}
+		/* If we created a new class-directory setup tagging */
+		if (dev->class->tag_type)
+			sysfs_make_tagged_dir(k, dev->class->tag_type);
+
 		/* do not emit an uevent for this simple "glue" directory */
 		return k;
 	}
@@ -709,7 +725,7 @@ out_device:
 out_busid:
 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
+		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
 				  dev->bus_id);
 #else
 	/* link in the class directory pointing to the device */
@@ -727,7 +743,7 @@ out_busid:
 	return 0;
 
 out_busid:
-	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev->bus_id);
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev->bus_id);
 #endif
 
 out_subsys:
@@ -755,13 +771,13 @@ static void device_remove_class_symlinks(struct device *dev)
 
 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
+		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
 				  dev->bus_id);
 #else
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
 
-	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev->bus_id);
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev->bus_id);
 #endif
 
 	sysfs_remove_link(&dev->kobj, "subsystem");
@@ -1344,6 +1360,16 @@ int device_rename(struct device *dev, char *new_name)
 	strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
 	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
 
+#ifndef CONFIG_SYSFS_DEPRECATED
+	if (dev->class &&
+	    (dev->kobj.parent != &dev->class->p->class_subsys.kobj)) {
+		error = sysfs_rename_link(&dev->class->p->class_subsys.kobj,
+			&dev->kobj, old_device_name, new_name);
+		if (error)
+			goto out;
+	}
+#endif
+
 	error = kobject_rename(&dev->kobj, new_name);
 	if (error) {
 		strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
@@ -1352,23 +1378,19 @@ int device_rename(struct device *dev, char *new_name)
 
 #ifdef CONFIG_SYSFS_DEPRECATED
 	if (old_class_name) {
+		error = -ENOMEM;
 		new_class_name = make_class_name(dev->class->name, &dev->kobj);
-		if (new_class_name) {
-			error = sysfs_create_link(&dev->parent->kobj,
-						  &dev->kobj, new_class_name);
-			if (error)
-				goto out;
-			sysfs_remove_link(&dev->parent->kobj, old_class_name);
-		}
+		if (new_class_name)
+			error = sysfs_rename_link(&dev->parent->kobj,
+						  &dev->kobj,
+						  old_class_name,
+						  new_class_name);
 	}
 #else
 	if (dev->class) {
-		error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
-					  &dev->kobj, dev->bus_id);
-		if (error)
-			goto out;
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
-				  old_device_name);
+		error = sysfs_rename_link(&dev->class->p->class_subsys.kobj,
+					  &dev->kobj, old_device_name,
+					  dev->bus_id);
 	}
 #endif
 
diff --git a/include/linux/device.h b/include/linux/device.h
index d9886a6..8e84539 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -191,6 +191,9 @@ struct class {
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
 
+	enum sysfs_tag_type tag_type;
+	const void *(*sysfs_tag)(struct device *dev);
+
 	struct class_private *p;
 };
 
-- 
1.5.3.rc6.17.g1911

[PATCH 13/15] Revert "netns: Fix device renaming for sysfs"

[Eric W. Biederman]

This reverts commit aaf8cdc34ddba08122f02217d9d684e2f9f5d575.

Drivers like the ipw2100 call device_create_group when they
are initialized and device_remove_group when they are shutdown.
Moving them between namespaces deletes their sysfs groups early.

In particular the following call chain results.
netdev_unregister_kobject -> device_del -> kobject_del -> sysfs_remove_dir
With sysfs_remove_dir recursively deleting all of it's subdirectories,
and nothing adding them back.

Ouch!

Therefore we need to call something that ultimate calls sysfs_mv_dir
as that sysfs function can move sysfs directories between namespaces
without deleting their subdirectories or their contents.   Allowing
us to avoid placing extra boiler plate into every driver that does
something interesting with sysfs.

Currently the function that provides that capability is device_rename.
That is the code works without nasty side effects as originally written.

So remove the misguided fix for moving devices between namespaces.  The
bug in the kobject layer that inspired it has now been recognized and
fixed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 net/core/dev.c       |    4 +---
 net/core/net-sysfs.c |    7 +------
 net/core/net-sysfs.h |    2 +-
 3 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index fca23a3..585584d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3806,7 +3806,6 @@ int register_netdevice(struct net_device *dev)
 		}
 	}
 
-	netdev_initialize_kobject(dev);
 	ret = netdev_register_kobject(dev);
 	if (ret)
 		goto err_uninit;
@@ -4239,8 +4238,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	}
 
 	/* Fixup kobjects */
-	netdev_unregister_kobject(dev);
-	err = netdev_register_kobject(dev);
+	err = device_rename(&dev->dev, dev->name);
 	WARN_ON(err);
 
 	/* Add the device back in the hashes */
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 90e2177..4e7b847 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -449,6 +449,7 @@ int netdev_register_kobject(struct net_device *net)
 	struct device *dev = &(net->dev);
 	struct attribute_group **groups = net->sysfs_groups;
 
+	device_initialize(dev);
 	dev->class = &net_class;
 	dev->platform_data = net;
 	dev->groups = groups;
@@ -469,12 +470,6 @@ int netdev_register_kobject(struct net_device *net)
 	return device_add(dev);
 }
 
-void netdev_initialize_kobject(struct net_device *net)
-{
-	struct device *device = &(net->dev);
-	device_initialize(device);
-}
-
 int netdev_kobject_init(void)
 {
 	return class_register(&net_class);
diff --git a/net/core/net-sysfs.h b/net/core/net-sysfs.h
index 14e7524..f5f108d 100644
--- a/net/core/net-sysfs.h
+++ b/net/core/net-sysfs.h
@@ -4,5 +4,5 @@
 int netdev_kobject_init(void);
 int netdev_register_kobject(struct net_device *);
 void netdev_unregister_kobject(struct net_device *);
-void netdev_initialize_kobject(struct net_device *);
+
 #endif
-- 
1.5.3.rc6.17.g1911

[PATCH 14/15] netns: Enable tagging for net_class directories in sysfs

[Eric W. Biederman]

The problem.  Network devices show up in sysfs and with the network
namespace active multiple devices with the same name can show up in
the same directory, ouch!

To avoid that problem and allow existing applications in network namespaces
to see the same interface that is currently presented in sysfs, this
patch enables the tagging directory support in sysfs.

By using the network namespace pointers as tags to separate out the
the sysfs directory entries we ensure that we don't have conflicts
in the directories and applications only see a limited set of
the network devices.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 include/linux/sysfs.h |    1 +
 net/Kconfig           |    2 +-
 net/core/net-sysfs.c  |   33 +++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index c3a30ce..1ed31bb 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -80,6 +80,7 @@ struct sysfs_ops {
 
 enum sysfs_tag_type {
 	SYSFS_TAG_TYPE_NONE = 0,
+	SYSFS_TAG_TYPE_NETNS,
 	SYSFS_TAG_TYPES
 };
 
diff --git a/net/Kconfig b/net/Kconfig
index acbf7c6..9aad03b 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -30,7 +30,7 @@ menu "Networking options"
 config NET_NS
 	bool "Network namespace support"
 	default n
-	depends on EXPERIMENTAL && !SYSFS && NAMESPACES
+	depends on EXPERIMENTAL && NAMESPACES
 	help
 	  Allow user space to create what appear to be multiple instances
 	  of the network stack.
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 4e7b847..6227a28 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -13,7 +13,9 @@
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
+#include <linux/nsproxy.h>
 #include <net/sock.h>
+#include <net/net_namespace.h>
 #include <linux/rtnetlink.h>
 #include <linux/wireless.h>
 #include <net/iw_handler.h>
@@ -385,6 +387,24 @@ static struct attribute_group wireless_group = {
 };
 #endif
 
+static const void *net_sysfs_mount_tag(void)
+{
+	return current->nsproxy->net_ns;
+}
+
+static struct sysfs_tag_type_operations net_tag_type_operations = {
+	.mount_tag = net_sysfs_mount_tag,
+};
+
+static void net_sysfs_net_exit(struct net *net)
+{
+	sysfs_exit_tag(SYSFS_TAG_TYPE_NETNS, net);
+}
+
+static struct pernet_operations sysfs_net_ops = {
+	.exit = net_sysfs_net_exit,
+};
+
 #endif /* CONFIG_SYSFS */
 
 #ifdef CONFIG_HOTPLUG
@@ -421,6 +441,13 @@ static void netdev_release(struct device *d)
 	kfree((char *)dev - dev->padded);
 }
 
+static const void *net_sysfs_tag(struct device *d)
+{
+	struct net_device *dev;
+	dev = container_of(d, struct net_device, dev);
+	return dev_net(dev);
+}
+
 static struct class net_class = {
 	.name = "net",
 	.dev_release = netdev_release,
@@ -430,6 +457,8 @@ static struct class net_class = {
 #ifdef CONFIG_HOTPLUG
 	.dev_uevent = netdev_uevent,
 #endif
+	.tag_type = SYSFS_TAG_TYPE_NETNS,
+	.sysfs_tag = net_sysfs_tag,
 };
 
 /* Delete sysfs entries but hold kobject reference until after all
@@ -472,5 +501,9 @@ int netdev_register_kobject(struct net_device *net)
 
 int netdev_kobject_init(void)
 {
+#ifdef CONFIG_SYSFS
+	sysfs_register_tag_type(SYSFS_TAG_TYPE_NETNS, &net_tag_type_operations);
+	register_pernet_subsys(&sysfs_net_ops);
+#endif
 	return class_register(&net_class);
 }
-- 
1.5.3.rc6.17.g1911

[PATCH 15/15] sysfs: user namespaces: fix bug with clone(CLONE_NEWUSER) with fairsched

[Eric W. Biederman]

Mark the /sys/kernel/uids directory to be tagged so that processes in
different user namespaces can remount /sys and see their own uid
listings.

Without this patch, having CONFIG_FAIR_SCHED=y makes user namespaces
unusable, because when you
  clone(CLONE_NEWUSER)
it will auto-create the root userid and try to create
/sys/kernel/uids/0.  Since that already exists from the parent user
namespace, the create fails, and the clone misleadingly ends up
returning -ENOMEM.

This patch fixes the issue by allowing each user namespace to remount
/sys, and having /sys filter the /sys/kernel/uid/ entries by user
namespace.

Changelong:
v2 - Reworked for the updated sysfs api

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 include/linux/sched.h   |    1 +
 include/linux/sysfs.h   |    1 +
 kernel/user.c           |   22 ++++++++++++++++++++++
 kernel/user_namespace.c |    1 +
 4 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index c5d3f84..d2be6a5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -598,6 +598,7 @@ struct user_struct {
 	/* Hash table maintenance information */
 	struct hlist_node uidhash_node;
 	uid_t uid;
+	struct user_namespace *user_ns;
 
 #ifdef CONFIG_USER_SCHED
 	struct task_group *tg;
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 1ed31bb..ecb942c 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -81,6 +81,7 @@ struct sysfs_ops {
 enum sysfs_tag_type {
 	SYSFS_TAG_TYPE_NONE = 0,
 	SYSFS_TAG_TYPE_NETNS,
+	SYSFS_TAG_TYPE_USERNS,
 	SYSFS_TAG_TYPES
 };
 
diff --git a/kernel/user.c b/kernel/user.c
index 865ecf5..ca29fbc 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -53,6 +53,7 @@ struct user_struct root_user = {
 	.files		= ATOMIC_INIT(0),
 	.sigpending	= ATOMIC_INIT(0),
 	.locked_shm     = 0,
+	.user_ns	= &init_user_ns,
 #ifdef CONFIG_USER_SCHED
 	.tg		= &init_task_group,
 #endif
@@ -230,16 +231,33 @@ static struct attribute *uids_attributes[] = {
 	NULL
 };
 
+static const void *uids_mount_tag(void)
+{
+	return current->nsproxy->user_ns;
+}
+
+static struct sysfs_tag_type_operations uids_tag_type_operations = {
+	.mount_tag = uids_mount_tag,
+};
+
 /* the lifetime of user_struct is not managed by the core (now) */
 static void uids_release(struct kobject *kobj)
 {
 	return;
 }
 
+static const void *uids_sysfs_tag(struct kobject *kobj)
+{
+	struct user_struct *up;
+	up = container_of(kobj, struct user_struct, kobj);
+	return up->user_ns;
+}
+
 static struct kobj_type uids_ktype = {
 	.sysfs_ops = &kobj_sysfs_ops,
 	.default_attrs = uids_attributes,
 	.release = uids_release,
+	.sysfs_tag = uids_sysfs_tag,
 };
 
 /* create /sys/kernel/uids/<uid>/cpu_share file for this user */
@@ -272,6 +290,9 @@ int __init uids_sysfs_init(void)
 	if (!uids_kset)
 		return -ENOMEM;
 
+	sysfs_register_tag_type(SYSFS_TAG_TYPE_USERNS, &uids_tag_type_operations);
+	sysfs_make_tagged_dir(&uids_kset->kobj, SYSFS_TAG_TYPE_USERNS);
+
 	return uids_user_create(&root_user);
 }
 
@@ -405,6 +426,7 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
 
 		new->uid = uid;
 		atomic_set(&new->__count, 1);
+		new->user_ns = ns;
 
 		if (sched_create_user(new) < 0)
 			goto out_free_user;
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a9ab059..f67bbe0 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -71,6 +71,7 @@ void free_user_ns(struct kref *kref)
 	struct user_namespace *ns;
 
 	ns = container_of(kref, struct user_namespace, kref);
+	sysfs_exit_tag(SYSFS_TAG_TYPE_USERNS, ns);
 	release_uids(ns);
 	kfree(ns);
 }
-- 
1.5.3.rc6.17.g1911

Re: [PATCH 00/15] sysfs support for namespaces

[Eric W. Biederman]

I should mention patches 1-12 are the core of the work.

Patches 13-15 are the users.  Included in complete form primarily to
aid review.

Eric

Re: [PATCH 01/15] kobject: Cleanup kobject_rename and !CONFIG_SYSFS

[Tejun Heo]

Eric W. Biederman wrote:
> It finally dawned on me what the clean fix to sysfs_rename_dir
> calling kobject_set_name is.  Move the work into kobject_rename
> where it belongs.  The callers serialize us anyway so this is
> safe.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Nice clean up.  Acked-by: Tejun Heo <tj@kernel.org>

-- 
tejun

Re: [PATCH 06/15] Introduce sysfs_sd_setattr and fix sysfs_chmod

[Tejun Heo]

Eric W. Biederman wrote:
> Currently sysfs_chmod calls sys_setattr which in turn calls
> inode_change_ok which checks to see if it is ok for the current user
> space process to change tha attributes. Since sysfs_chmod_file has
> only kernel mode clients denying them permission if user space is the
> problem is completely inappropriate.
> 
> Therefore factor out sysfs_sd_setattr which does not call
> inode_change_ok and modify sysfs_chmod_file to call it.
> 
> In addition setting victim_sd->s_mode explicitly in sysfs_chmod_file
> is redundant so remove that as well.
> 
> Thanks to Tejun Heo <htejun@gmail.com>, and
> Daniel Lezcano <dlezcano@fr.ibm.com> for working on this
> and spotting this case.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
tejun

Re: [PATCH 07/15] sysfs: sysfs_chmod_file handle multiple superblocks

[Tejun Heo]

Eric W. Biederman wrote:
> Teach sysfs_chmod_file how to handle multiple sysfs superblocks.
> Since we only have one inode per sd the only thing we have to deal
> with is multiple dentries for sending fs notifications.  This might
> dup the inode notifications oh well.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Great, Acked-by: Tejun Heo <tj@kernel.org>

-- 
tejun

Re: [PATCH 08/15] sysfs: Make sysfs_mount static once again.

[Tejun Heo]

Eric W. Biederman wrote:
> Accessing the internal sysfs_mount is error prone in the context
> of multiple super blocks, and nothing needs it.  Not even the
> sysfs crash debugging patch (although it did in an earlier version).
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Eric W. Biederman wrote:
> This patch enables tagging on every class directory if struct class
> has a tag_type.
> 
> In addition device_del and device_rename were modified to uses
> sysfs_delete_link and sysfs_rename_link respectively to ensure
> when these operations happen on devices whose classes have
> tag_ops that they work properly.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>

Okay, I went through the users this time but I still think
determine-tags-by-callbacks is a bad idea.  Please just add const void
*tag to kobject and set it during initialization.  If you want to move a
device from one tag to another, implement kobject_rename_tagged(kobj,
new_name, new_tag).

The determine-tag-by-callback basically multiplexes basic functions to
do tag-specific things which are determined by ktype callback called
back from down the layer.  It's simply a bad interface.  Those
operations become something else depending on how those callbacks
behave.  That's unnecessarily subtle.  Advertising what it's gonna do in
the function name and as arguments is way more straight forward and it's
not like determining or renaming tags should be done asynchronously.

I personally think it would be better to make tags explicit in the mount
interface too but if extracting ns information from the mounting process
is what's currently being done, well...

I'm sorry but Nacked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Thank you for your opinion.

Incremental patches to make things more beautiful are welcome.

Please remember we are not building lisp.  The goal is code that works today.

Since we are not talking about correctness of the code.  Since we are not
talking about interfaces with user space.  Since we are talking something
that is currently about 100 lines of code, and so will be easy to change
even after it is merged.   I don't understand how discussing this further
is useful.  Especially when I get a NAK  based on the feel that the code
is ugly.

As for your main objection.  Adding a accessor method to an object versus
adding a data field that contain the same thing.  The two are effectively
identical.  With the practical difference in my eyes that an accessor method
prevents data duplication which reduces maintenance and reduces skew problems,
and it keeps the size of struct kobject small.  Since you think methods are
horrible I must respectfully disagree with you.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Hello, Eric.

Eric W. Biederman wrote:
> Thank you for your opinion.
> 
> Incremental patches to make things more beautiful are welcome.
> 
> Please remember we are not building lisp.  The goal is code that works today.
> 
> Since we are not talking about correctness of the code.  Since we are not
> talking about interfaces with user space.  Since we are talking something
> that is currently about 100 lines of code, and so will be easy to change
> even after it is merged.   I don't understand how discussing this further
> is useful.  Especially when I get a NAK  based on the feel that the code
> is ugly.

I'm sorry if I gave you the impression of being draconian.  Explanations
below.

> As for your main objection.  Adding a accessor method to an object versus
> adding a data field that contain the same thing.  The two are effectively
> identical.  With the practical difference in my eyes that an accessor method
> prevents data duplication which reduces maintenance and reduces skew problems,
> and it keeps the size of struct kobject small.  Since you think methods are
> horrible I must respectfully disagree with you.

Yeah, it seems we should agree to disagree here.  I think using callback
for static values is a really bad idea.  It obfuscates the code and
opens up a big hole for awful misuses.  Greg, what do you think?

As we're very close to rc1 window, I think we can work out a solution
here.  The reason why I nack'd was because the change wouldn't take too
much effort and I thought it could be done before -rc1.  Unless you
disagree with making tags static values, I'll try to write up a patch to
do so.  If you (and Greg) think the callback interface is better, we can
merge the code as-is and update (or not) later.

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Greg KH]

On Fri, Jul 04, 2008 at 10:57:15PM +0900, Tejun Heo wrote:
> Hello, Eric.
> 
> Eric W. Biederman wrote:
> > Thank you for your opinion.
> > 
> > Incremental patches to make things more beautiful are welcome.
> > 
> > Please remember we are not building lisp.  The goal is code that works today.
> > 
> > Since we are not talking about correctness of the code.  Since we are not
> > talking about interfaces with user space.  Since we are talking something
> > that is currently about 100 lines of code, and so will be easy to change
> > even after it is merged.   I don't understand how discussing this further
> > is useful.  Especially when I get a NAK  based on the feel that the code
> > is ugly.
> 
> I'm sorry if I gave you the impression of being draconian.  Explanations
> below.
> 
> > As for your main objection.  Adding a accessor method to an object versus
> > adding a data field that contain the same thing.  The two are effectively
> > identical.  With the practical difference in my eyes that an accessor method
> > prevents data duplication which reduces maintenance and reduces skew problems,
> > and it keeps the size of struct kobject small.  Since you think methods are
> > horrible I must respectfully disagree with you.
> 
> Yeah, it seems we should agree to disagree here.  I think using callback
> for static values is a really bad idea.  It obfuscates the code and
> opens up a big hole for awful misuses.  Greg, what do you think?

Sorry, Greg is walking out the door in 30 minutes for a much needed week
long vacation and can't look into this right now :(

I'll be able to review it next weekend, sorry for the delay.

greg k-h

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:

> Sorry, Greg is walking out the door in 30 minutes for a much needed week
> long vacation and can't look into this right now :(
>
> I'll be able to review it next weekend, sorry for the delay.

Understood and no problem.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Tejun Heo <htejun@gmail.com> writes:

> Yeah, it seems we should agree to disagree here.  I think using callback
> for static values is a really bad idea.  It obfuscates the code and
> opens up a big hole for awful misuses.  Greg, what do you think?

The misuse argument is small because currently all users must be compiled
into the kernel and must add to the static enumeration.  I'm afraid we
are making the facility over general for the problem at hand.

> As we're very close to rc1 window, I think we can work out a solution
> here.  The reason why I nack'd was because the change wouldn't take too
> much effort and I thought it could be done before -rc1.  Unless you
> disagree with making tags static values, I'll try to write up a patch to
> do so.  If you (and Greg) think the callback interface is better, we can
> merge the code as-is and update (or not) later.

Making a change and pushing down into the patches is much more time intensive
then I would like.  The last round of changes simple as they were took something
between 16 and 30 hours, and has left me sapped.  Keeping all of the other
pieces in flight in all of the other patches so I can't just focus on the
change at hand is what makes it difficult at this point.

Adding an additional patch on top isn't too bad, but my creativity is sapped on
this right now.  I agree that a function called device_rename isn't the best
possible name when we are changing tags, but I can't think of anything that
seems better.

I know in the users that the tags are already quite static and that I call
kobject_rename in the one case where they change (which is a significant
exception).  So that part doesn't concern me as I have not intention of using
the interface like that.  Ultimately I don't care as long as we have code
that works.

Eric

Re: [PATCH 00/15] sysfs support for namespaces

[Eric W. Biederman]

> These patches are based off of 2.6.26-rc8 + the -gregkh tree from
> last night.  Hopefully that means they apply -mm -gregkh and
> -linux-next.

A quick update.   My patchset conflicts with the recently added
  driver-core-suppress-sysfs-warnings-for-device_rename.patch

> driver core: Suppress sysfs warnings for device_rename().
> 
> Renaming network devices to an already existing name is not
> something we want sysfs to print a scary warning for, since the
> callers can deal with this correctly. So let's introduce
> sysfs_create_link_nowarn() which gets rid of the common warning.

This patch is unnecessary as that path is never exercised anymore.
as: dev_change_name returns early in the case of a noop rename.

In addition my introduction sysfs_rename_link handles this case
cleanly by first removing the old link and then creating the new
link.  Preventing false positives when the link names are the same.

So it should be safe to drop Cornelia patch without a reoccurance
of scary errors.

Eric

Re: [PATCH 00/15] sysfs support for namespaces

[Cornelia Huck]

On Sat, 05 Jul 2008 21:42:57 -0700,
ebiederm@xmission.com (Eric W. Biederman) wrote:

> 
> > These patches are based off of 2.6.26-rc8 + the -gregkh tree from
> > last night.  Hopefully that means they apply -mm -gregkh and
> > -linux-next.
> 
> A quick update.   My patchset conflicts with the recently added
>   driver-core-suppress-sysfs-warnings-for-device_rename.patch
> 
> > driver core: Suppress sysfs warnings for device_rename().
> > 
> > Renaming network devices to an already existing name is not
> > something we want sysfs to print a scary warning for, since the
> > callers can deal with this correctly. So let's introduce
> > sysfs_create_link_nowarn() which gets rid of the common warning.
> 
> This patch is unnecessary as that path is never exercised anymore.
> as: dev_change_name returns early in the case of a noop rename.

My impression was that the networking folks didn't want any warnings for
renaming failures, not just not for renaming a device to the same name.

> 
> In addition my introduction sysfs_rename_link handles this case
> cleanly by first removing the old link and then creating the new
> link.  Preventing false positives when the link names are the same.

sysfs_rename_link() looks cleaner, I agree.

> 
> So it should be safe to drop Cornelia patch without a reoccurance
> of scary errors.

Hm, the description looks badly worded - I unfortunately left the old
text unchanged when I respun the patch :( The patch re-introduces the
warning in sysfs_add_one() which had been removed in the meanwhile and
makes device_rename() use a non-warning version. I still think we want
a warning for the general case since this is usually caused be some
problems in the calling code (and the alternative would be to add
checks to all callers.)

Re: [PATCH 00/15] sysfs support for namespaces

[Eric W. Biederman]

Cornelia Huck <cornelia.huck@de.ibm.com> writes:

> My impression was that the networking folks didn't want any warnings for
> renaming failures, not just not for renaming a device to the same name.

Which would be reasonable.  Because all of the checks have been done
before sysfs is called so if sysfs sees a problem it is a sysfs bug.

>> In addition my introduction sysfs_rename_link handles this case
>> cleanly by first removing the old link and then creating the new
>> link.  Preventing false positives when the link names are the same.
>
> sysfs_rename_link() looks cleaner, I agree.
>
>> 
>> So it should be safe to drop Cornelia patch without a reoccurance
>> of scary errors.
>
> Hm, the description looks badly worded - I unfortunately left the old
> text unchanged when I respun the patch :( The patch re-introduces the
> warning in sysfs_add_one() which had been removed in the meanwhile and
> makes device_rename() use a non-warning version. I still think we want
> a warning for the general case since this is usually caused be some
> problems in the calling code (and the alternative would be to add
> checks to all callers.)

Right.  We just need to get the sysfs paths clean enough that we don't
emit false positives.  I think I have accomplished that for rename.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:
>
> Sorry, Greg is walking out the door in 30 minutes for a much needed week
> long vacation and can't look into this right now :(
>
> I'll be able to review it next weekend, sorry for the delay.

Any progress in reviewing these changes, and seeing if you can stand
to merge them?

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Eric W. Biederman wrote:
> Greg KH <gregkh@suse.de> writes:
>> Sorry, Greg is walking out the door in 30 minutes for a much needed week
>> long vacation and can't look into this right now :(
>>
>> I'll be able to review it next weekend, sorry for the delay.
> 
> Any progress in reviewing these changes, and seeing if you can stand
> to merge them?

Greg, please disregard my earlier NACKs and commit the patches if you're
okay with them.  I'm working on cleaning it up but I don't think I'll be
able to make it in time for merge window and as Eric said getting the
functionality in place is more important at this point as it doesn't
affect user visible interface.

Eric, with the multiple superblocks, sysfs now uses inode from the
default sysfs_sb with dentries from other sb's.  Is this okay?  Are
there any other filesystems which do this?

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Tejun Heo <htejun@gmail.com> writes:

> Greg, please disregard my earlier NACKs and commit the patches if you're
> okay with them.  I'm working on cleaning it up but I don't think I'll be
> able to make it in time for merge window and as Eric said getting the
> functionality in place is more important at this point as it doesn't
> affect user visible interface.
>
> Eric, with the multiple superblocks, sysfs now uses inode from the
> default sysfs_sb with dentries from other sb's.  Is this okay?  Are
> there any other filesystems which do this?

I don't know of any other filesystems where this unique challenge arises.
/proc almost qualifies but it never needs to be modified.

It is certainly ok to go from multiple dentries to a single inode.
I'm trying to remember why I choose to do that.  I think both because it simplifies
the locking and keeps us more efficient in the icache.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Hello,

Eric W. Biederman wrote:
>> Eric, with the multiple superblocks, sysfs now uses inode from the
>> default sysfs_sb with dentries from other sb's.  Is this okay?  Are
>> there any other filesystems which do this?
> 
> I don't know of any other filesystems where this unique challenge arises.
> /proc almost qualifies but it never needs to be modified.
> 
> It is certainly ok to go from multiple dentries to a single inode.
> I'm trying to remember why I choose to do that.  I think both because it simplifies
> the locking and keeps us more efficient in the icache.

It's a bit scary tho.  Working inode->i_dentry or dentry->d_alias
crosses multiple sb's.  sysfs isn't too greedy about dcache/icache.
Only open files and directories hold them and only single copy of
sysfs_dirent is there for most nodes.  Wouldn't it be better to stay on
the safer side and use separate inode hierarchy?

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Tejun Heo <htejun@gmail.com> writes:

> It's a bit scary tho.  Working inode->i_dentry or dentry->d_alias
> crosses multiple sb's.  sysfs isn't too greedy about dcache/icache.
> Only open files and directories hold them and only single copy of
> sysfs_dirent is there for most nodes.  Wouldn't it be better to stay on
> the safer side and use separate inode hierarchy?

To do that I believe we would need to ensure sysfs does not use 
the inode->i_mutex lock except to keep the VFS layer out.  Allowing us
to safely change the directory structure, without holding it.

You raise a good point about inode->i_dentry and dentry->d_alias.
Generally they are used by fat like filesystems but I am starting to
see uses in generic pieces of code.  I don't see any problems today
but yes it would be good to do the refactoring to allow us to duplicate
the inodes. 

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Hello, Eric.

Eric W. Biederman wrote:
> Tejun Heo <htejun@gmail.com> writes:
> 
>> It's a bit scary tho.  Working inode->i_dentry or dentry->d_alias
>> crosses multiple sb's.  sysfs isn't too greedy about dcache/icache.
>> Only open files and directories hold them and only single copy of
>> sysfs_dirent is there for most nodes.  Wouldn't it be better to stay on
>> the safer side and use separate inode hierarchy?
> 
> To do that I believe we would need to ensure sysfs does not use 
> the inode->i_mutex lock except to keep the VFS layer out.  Allowing us
> to safely change the directory structure, without holding it.

I don't think sysfs is depending on i_mutex anymore but I need to go
through the code to make sure.

> You raise a good point about inode->i_dentry and dentry->d_alias.
> Generally they are used by fat like filesystems but I am starting to
> see uses in generic pieces of code.  I don't see any problems today
> but yes it would be good to do the refactoring to allow us to duplicate
> the inodes. 

Yeah, I can't spot any place which can cause actual problem yet but it's
still scary as we're breaking a vfs assumption and even if it's not a
problem now, future seemingly unrelated changes can break things subtly.

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Tejun Heo wrote:
> Hello, Eric.
> 
> Eric W. Biederman wrote:
>> Tejun Heo <htejun@gmail.com> writes:
>>
>>> It's a bit scary tho.  Working inode->i_dentry or dentry->d_alias
>>> crosses multiple sb's.  sysfs isn't too greedy about dcache/icache.
>>> Only open files and directories hold them and only single copy of
>>> sysfs_dirent is there for most nodes.  Wouldn't it be better to stay on
>>> the safer side and use separate inode hierarchy?
>> To do that I believe we would need to ensure sysfs does not use 
>> the inode->i_mutex lock except to keep the VFS layer out.  Allowing us
>> to safely change the directory structure, without holding it.
> 
> I don't think sysfs is depending on i_mutex anymore but I need to go
> through the code to make sure.
> 
>> You raise a good point about inode->i_dentry and dentry->d_alias.
>> Generally they are used by fat like filesystems but I am starting to
>> see uses in generic pieces of code.  I don't see any problems today
>> but yes it would be good to do the refactoring to allow us to duplicate
>> the inodes. 
> 
> Yeah, I can't spot any place which can cause actual problem yet but it's
> still scary as we're breaking a vfs assumption and even if it's not a
> problem now, future seemingly unrelated changes can break things subtly.

Okay, one small problem spotted.  It seems invalidate_inodes() can fail
which will make generic_shutdown_super() complain.  It's not a fatal
failure tho.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Tejun Heo <teheo@suse.de> writes:

> Okay, one small problem spotted.  It seems invalidate_inodes() can fail
> which will make generic_shutdown_super() complain.  It's not a fatal
> failure tho.

How when the inode list is empty?  We don't unmount the superblock that
has the inodes.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Tejun Heo <htejun@gmail.com> writes:
>> To do that I believe we would need to ensure sysfs does not use 
>> the inode->i_mutex lock except to keep the VFS layer out.  Allowing us
>> to safely change the directory structure, without holding it.
>
> I don't think sysfs is depending on i_mutex anymore but I need to go
> through the code to make sure.

The vfs still does. So at least for directory tree manipulation  we
need to hold i_mutex before we grab sysfs_mutex.

I think that means we need to unscramble the whole set of locking
order issues.

In lookup we have:
local_vfs_lock -> fs_global_lock

In modifications we have:
fs_global_lock -> local_vfs_lock

Which is the definition of a lock ordering problem.

Currently we play jump through some significant hoops to keep things
in local_vfs_lock -> fs_global_lock order.

If we also take the rename_mutex on directory adds and deletes we
may be able to keep jumping through those hoops.  However I expect
we would be in a much better situation if we could figure out how
to avoid the problem.

It looks like the easy way to handle this is to make the sysfs_dirent
list rcu protected.  Which means we can fix our lock ordering problem
without VFS modifications.  Allowing the locking to always
be: sysfs_mutex ... i_mutex.

After that it would be safe and a good idea to have unshared
inodes between superblocks, just so we don't surprise anyone
making generic VFS assumptions.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Greg KH]

On Wed, Jul 16, 2008 at 12:25:24PM +0900, Tejun Heo wrote:
> Eric W. Biederman wrote:
> > Greg KH <gregkh@suse.de> writes:
> >> Sorry, Greg is walking out the door in 30 minutes for a much needed week
> >> long vacation and can't look into this right now :(
> >>
> >> I'll be able to review it next weekend, sorry for the delay.
> > 
> > Any progress in reviewing these changes, and seeing if you can stand
> > to merge them?
> 
> Greg, please disregard my earlier NACKs and commit the patches if you're
> okay with them.  I'm working on cleaning it up but I don't think I'll be
> able to make it in time for merge window and as Eric said getting the
> functionality in place is more important at this point as it doesn't
> affect user visible interface.

Ok, I'll work to get these in where applicable.

thanks,

greg k-h

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Greg KH wrote:
> Ok, I'll work to get these in where applicable.

Did this get into 2.6.27?  Or will this have to wait till .28?

Thanks.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Greg KH]

On Fri, Jul 18, 2008 at 09:41:29PM +0900, Tejun Heo wrote:
> Greg KH wrote:
> > Ok, I'll work to get these in where applicable.
> 
> Did this get into 2.6.27?  Or will this have to wait till .28?

I haven't sent any patches to Linus yet for 2.6.27, so it hasn't gotten
there yet.

And due to the intrusiveness, and the fact that this hasn't been tested
at all in any build tree yet, I can't in good concious submit this for
.27 either.

Part of this is my fault, I know, due to vacation and work, but also
lots is due to the fact that the code showed up so late in the
development cycle.

I'll add it to my tree, and get it some testing in the next cycle of
linux-next until 2.6.27 is out, and then if it's still looking good, go
into .28.

Hope this helps,

greg k-h

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:

> On Fri, Jul 18, 2008 at 09:41:29PM +0900, Tejun Heo wrote:
>> Greg KH wrote:
>> > Ok, I'll work to get these in where applicable.
>> 
>> Did this get into 2.6.27?  Or will this have to wait till .28?
>
> I haven't sent any patches to Linus yet for 2.6.27, so it hasn't gotten
> there yet.
>
> And due to the intrusiveness, and the fact that this hasn't been tested
> at all in any build tree yet, I can't in good concious submit this for
> .27 either.
>
> Part of this is my fault, I know, due to vacation and work, but also
> lots is due to the fact that the code showed up so late in the
> development cycle.

The code showed up at least by the beginning of may, and the code has
been around for 9 months or more.  I just haven't always had the
energy to retransmit every time it has gotten dropped.  The last spin
of it was very late I agree.

> I'll add it to my tree, and get it some testing in the next cycle of
> linux-next until 2.6.27 is out, and then if it's still looking good, go
> into .28.

I think that is unnecessarily precautions but reasonable.  That should at
least keep other sysfs patches from coming in and causing bit rot.

Eric

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Tejun Heo]

Hello, Greg.

Greg KH wrote:
> On Fri, Jul 18, 2008 at 09:41:29PM +0900, Tejun Heo wrote:
>> Greg KH wrote:
>>> Ok, I'll work to get these in where applicable.
>> Did this get into 2.6.27?  Or will this have to wait till .28?
> 
> I haven't sent any patches to Linus yet for 2.6.27, so it hasn't gotten
> there yet.
> 
> And due to the intrusiveness, and the fact that this hasn't been tested
> at all in any build tree yet, I can't in good concious submit this for
> .27 either.
> 
> Part of this is my fault, I know, due to vacation and work, but also
> lots is due to the fact that the code showed up so late in the
> development cycle.

Heh... A lot of it is my fault too.  Probably my share is bigger than
anyone else's.  Sorry Eric.

> I'll add it to my tree, and get it some testing in the next cycle of
> linux-next until 2.6.27 is out, and then if it's still looking good, go
> into .28.

I was just curious how the merge will turn out as I'm about to do a
refresh pass on the sysfs locking and stuff.  I'm not sure yet whether
to put those changes on top of or below ns patches but if I'll always
keep the ns patches updated.

Thank you.

-- 
tejun

Re: [PATCH 12/15] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:

> I'll add it to my tree, and get it some testing in the next cycle of
> linux-next until 2.6.27 is out, and then if it's still looking good, go
> into .28.

Greg.  Where are we at with this?

I just looked at your tree and I don't perhaps I'm blind but I don't see
this patches, and it looks like you at least refreshed your patches
a day or two ago.

Eric

patch kobject-cleanup-kobject_rename-and-config_sysfs.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: kobject: Cleanup kobject_rename and !CONFIG_SYSFS

to my gregkh-2.6 tree.  Its filename is

    kobject-cleanup-kobject_rename-and-config_sysfs.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:11:54 2008
From: ebiederm@xmission.com (Eric W. Biederman)
Date: Thu, 03 Jul 2008 18:05:28 -0700
Subject: kobject: Cleanup kobject_rename and !CONFIG_SYSFS
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>, Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m1tzf6ihlz.fsf_-_@frodo.ebiederm.org>



It finally dawned on me what the clean fix to sysfs_rename_dir
calling kobject_set_name is.  Move the work into kobject_rename
where it belongs.  The callers serialize us anyway so this is
safe.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/dir.c        |    6 +-----
 include/linux/sysfs.h |    4 +---
 lib/kobject.c         |   17 +++++++++++++++--
 3 files changed, 17 insertions(+), 10 deletions(-)

--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -830,16 +830,12 @@ int sysfs_rename_dir(struct kobject * ko
 	if (!new_dentry)
 		goto out_unlock;
 
-	/* rename kobject and sysfs_dirent */
+	/* rename sysfs_dirent */
 	error = -ENOMEM;
 	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
 	if (!new_name)
 		goto out_unlock;
 
-	error = kobject_set_name(kobj, "%s", new_name);
-	if (error)
-		goto out_unlock;
-
 	dup_name = sd->s_name;
 	sd->s_name = new_name;
 
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -20,8 +20,6 @@
 struct kobject;
 struct module;
 
-extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
-			    __attribute__((format(printf, 2, 3)));
 /* FIXME
  * The *owner field is no longer used, but leave around
  * until the tree gets cleaned up fully.
@@ -149,7 +147,7 @@ static inline void sysfs_remove_dir(stru
 
 static inline int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
 {
-	return kobject_set_name(kobj, "%s", new_name);
+	return 0;
 }
 
 static inline int sysfs_move_dir(struct kobject *kobj,
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -447,6 +447,7 @@ int kobject_rename(struct kobject *kobj,
 {
 	int error = 0;
 	const char *devpath = NULL;
+	const char *dup_name = NULL, *name;
 	char *devpath_string = NULL;
 	char *envp[2];
 
@@ -470,15 +471,27 @@ int kobject_rename(struct kobject *kobj,
 	envp[0] = devpath_string;
 	envp[1] = NULL;
 
+	name = dup_name = kstrdup(new_name, GFP_KERNEL);
+	if (!name) {
+		error = -ENOMEM;
+		goto out;
+	}
+
 	error = sysfs_rename_dir(kobj, new_name);
+	if (error)
+		goto out;
+
+	/* Install the new kobject name */
+	dup_name = kobj->name;
+	kobj->name = name;
 
 	/* This function is mostly/only used for network interface.
 	 * Some hotplug package track interfaces by their name and
 	 * therefore want to know when the name is changed by the user. */
-	if (!error)
-		kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 
 out:
+	kfree(dup_name);
 	kfree(devpath_string);
 	kfree(devpath);
 	kobject_put(kobj);


Patches currently in gregkh-2.6 which might be from gregkh@suse.de are

.git/logs/refs/heads/master
.git/logs/refs/heads/origin
.git/logs/refs/remotes/aria/master
.git/logs/refs/remotes/aria/origin
.git/logs/HEAD
bad/pci-domain/pci-device-ensure-sysdata-initialised.patch
bad/pci-domain/pci-fix-the-x86-pci-domain-support-fix.patch
bad/pci-domain/x86-pci-domain-support-struct-pci_sysdata.patch
bad/pci-domain/x86-pci-domain-support-a-humble-fix.patch
bad/pci-domain/x86-pci-domain-support-the-meat.patch
bad/relayfs/relay-consolidate-relayfs-core-into-kernel-relay.c.patch
bad/relayfs/relay-relay-header-cleanup.patch
bad/relayfs/sysfs-add-__attr_relay-helper-for-relay-attributes.patch
bad/relayfs/sysfs-relay-channel-buffers-as-sysfs-attributes.patch
bad/usbip/usb-usbip-more-dead-code-fix.patch
bad/usbip/usb-usbip-build-fix.patch
bad/usbip/usb-usbip-warning-fixes.patch
bad/ndevfs.patch
bad/driver-sample.sh.patch
bad/driver-model-convert-driver-model-to-mutexes.patch
bad/gpl_future-test.patch
bad/gregkh-debugfs_example.patch
bad/i2c-device-id-lm75.patch
bad/speakup-kconfig-fix.patch
bad/speakup-build-fix.patch
bad/pci-test-that-drivers-properly-call-pci_set_master.patch
bad/pci-use-new-multi-phase-suspend-infrastructure.patch
bad/speakup-core.patch
bad/uio.patch
bad/usbfs2.patch
bad/no-more-non-gpl-modules.patch
bad/usb-serial-serqt_usb.patch
bad/spi-device.patch
bad/ata_piix-multithread.patch
bad/uio-irq.patch
bad/sysfs-crash-debugging.patch
bad/pci-dynamic-id-cleanup.patch
bad/pci-piggy-bus.patch
bad/input-device_type.patch
bad/usb-iphone-charge.patch
bad/sysfs-test.patch
bad/ohci-fix-toggle-bit-desynchronization-when-canceling-urbs.patch
bad/ldp/dvb-add-firesat-driver.patch
bad/ldp/video-add-the-go7007-driver.patch
bad/ldp/framebuffer-add-the-via-framebuffer-driver.patch
bad/ldp/net-add-alacritech-slicoss-driver.patch
bad/ldp/aectc-add-the-aectc-driver.patch
bad/ldp/me4000-firmware-file.patch
bad/ldp/novfs-add-the-novell-filesystem-client-kernel-module.patch
bad/ldp/net-add-et131x-driver.patch
bad/ldp/oms-add-oms-maxp-driver.patch
bad/ldp/me4000-add-pci-data-collection-driver.patch
bad/ldp/usb-add-usb-test-and-measurement-class-driver.patch
bad/ldp/kolter_1616-add-kolter_1616-pci-i-o-driver.patch
bad/ldp.next/usb-add-option-hso-driver.patch
bad/ldp.next/usb-add-sensoray-2255-v4l-driver.patch
bad/ldp.next/input-add-appleir-driver.patch
gregkh/gkh-version.patch
gregkh/sysrq-u-laptop.patch
usb/usb-gotemp.patch
usb/hso-fix-oops-in-read-write-callbacks.patch
usb/hso-fix-refcounting-on-the-ttyhsx-devices.patch
usb/usb-hso-make-tty_operations-const.patch
usb/usb-hso-minor-fixes-due-to-code-review.patch
usb/usb-add-config_usb_debug_messages-and-usb_dbg.patch
usb/usb-convert-the-usb-core-code-to-use-usb_dbg.patch
usb/usb-remove-config_usb_debug.patch
usb/usb-convert-the-usb-host-controller-code-to-use-usb_dbg.patch
usb/usb-remove-warn-macro-from-usb.h.patch
usb/usb-remove-info-macro-from-usb.h.patch
usb/hso-icon-322-detection-fix.patch
usb/hso-dev_kfree_skb-crash-fix.patch
usb/usb-add-new-pm-callback-methods-for-usb.patch
usb/drivers-usb-class-usblp.c-adjust-error-handling-code.patch
usb/usb-kill-urbs-permanently.patch
usb/usb-extend-poisoning-to-anchors.patch
usb/ub-remove-sg_stat.patch
usb/usb-added-driver-for-a-delcom-usb-7-segment-led-display.patch
usb/usb-add-udev-argument-to-interface-suspend-resume-functions.patch
usb/usb-defer-set-interface-for-suspended-devices.patch
usb/usb-don-t-rebind-before-complete-callback.patch
usb/usb-gadget-dummy_hcd-implement-set_wedge.patch
usb/usb-gadget-kconfig-cleanup.patch
usb/usb-gadget-net2280-implement-set_wedge.patch
usb/usb-let-some-usb-host-controllers-get-irq-flags-from-resource.patch
usb/usb-removed-unused-include-version.h.patch
usb.current/usb-cdc-acm-quirk-for-conexant-cx93010-usb-modem.patch
usb.current/usb-fix-bug-in-usb_unlink_anchored_urbs.patch
usb.current/usb-fix-pxa27x_udc-usb-speed-handling.patch
usb.current/usb-isp1760-fixed-trivial-math-in-comment.patch
usb.current/usb-serial-option-support-hsdpa-modem-a2502.patch
HOWTO
driver-core/put_device-might_sleep.patch
driver-core/sysfs-crash-debugging.patch
driver-core/warn-when-statically-allocated-kobjects-are-used.patch
driver-core/usb-gadget-make-gadget_core.ko.patch
driver-core/net-convert-the-phy_device-file-to-use-bus_find_device_by_name.patch
driver-core/s390-bus_id-dev_set_name-for-css-and-ccw-busses.patch
driver-core/driver-core-make-struct-platform_pm_ops-static.patch
driver-core/sysfs-support-sysfs_notify-from-atomic-context-with-new-sysfs_notify_dirent.patch
driver-core/driver-core-basic-infrastructure-for-per-module-dynamic-debug-messages.patch
driver-core/usb-gadget-move-f_acm.c-and-u_serial.c-gadget_acm_core.ko.patch
driver-core/usb-gadget-move-f_ecm.c-to-gadget_ecm_core.ko.patch
driver-core/usb-gadget-move-u_ether.c-to-gadget_ether_core.ko.patch
driver-core/usb-gadget-move-library-files-into-g_cdc.ko.patch
driver-core/usb-gadget-move-library-files-into-g_ether.ko.patch
driver-core/usb-gadget-move-library-files-into-g_file_storage.ko.patch
driver-core/usb-gadget-move-library-files-into-g_midi.ko.patch
driver-core/usb-gadget-move-library-files-into-g_printer.ko.patch
driver-core/usb-gadget-move-library-files-into-g_serial-ko.patch
driver-core/usb-gadget-move-library-files-into-g_zero.ko.patch
driver-core/device-create-block-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-char-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-ide-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-ieee1394-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-infiniband-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-misc-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-net-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-remove-device_create_drvdata.patch
driver-core/device-create-s390-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-scsi-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-sound-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-usb-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-video-convert-device_create_drvdata-to-device_create.patch
driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/driver-core-convert-to-new-device-api-to-allow-names-longer-than-20-chars.patch
driver-core/driver-core-lguest-convert-to-new-device-api-to-allow-names-longer-than-20-chars.patch
driver-core/driver-core-prepare-for-removal-of-20-char-limit-from-struct-device.patch
driver-core/s390-bus_id-dev_set_name-changes.patch
driver-core/s390-more-bus_id-dev_name-conversions.patch
driver-core/s390-use-s390_root_dev_-in-kvm_virtio.patch
driver-core/s390-bus_id-dev_name-conversions.patch
driver-core/driver-core-provide-a-dev_set_name-that-handles-names-longer-than-20-chars.patch
pending/perfmon-fix-up-some-static-kobject-usages.patch
pending/kobject-change-sys-kernel-uids-to-not-use-a-kset.patch
pending/kobjects-hook-them-up-to-the-debugobjects-infrastructure.patch
pending/firmware-add-kconfig-and-makefile-to-build-the-firmware-samples.patch
driver-core.current/dev_printk-constify-the-dev-argument.patch
driver-core.current/drivers-base-driver.c-remove-unused-to_dev-macro.patch
driver-core.current/japanese-translation-of-documentation-submitchecklist.patch
driver-core.current/kobject-replace-all-occurrences-of-with-instead-of-only-the-first-one.patch
driver-core.current/driver-model-anti-oopsing-medicine.patch
driver-core.current/pm-don-t-skip-device-pm-init-when-config_pm_sleep-isn-t-set-and-config_pm-is-set.patch
driver-core.current/driver-core-add-init_name-to-struct-device.patch
driver-core.current/pm-remove-warn_on-from-device_pm_add.patch
driver-core.current/block-drop-references-taken-by-class_find_device.patch
driver-core.current/block-fix-partial-read-of-proc-partitions-diskstats.patch

patch sysfs-implement-__sysfs_get_dentry.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: sysfs: Implement __sysfs_get_dentry

to my gregkh-2.6 tree.  Its filename is

    sysfs-implement-__sysfs_get_dentry.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:11:48 2008
From: ebiederm@xmission.com (Eric W. Biederman)
Date: Thu, 03 Jul 2008 18:09:04 -0700
Subject: sysfs: Implement __sysfs_get_dentry
To: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m1hcb6ihfz.fsf_-_@frodo.ebiederm.org>

From: Eric W. Biederman <ebiederm@xmission.com>


This function is similar but much simpler to sysfs_get_dentry
returns a sysfs dentry if one curently exists.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/dir.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -795,6 +795,45 @@ void sysfs_remove_dir(struct kobject * k
 	__sysfs_remove_dir(sd);
 }
 
+/**
+ *	__sysfs_get_dentry - get dentry for the given sysfs_dirent
+ *	@sb: superblock of the dentry to return
+ *	@sd: sysfs_dirent of interest
+ *
+ *	Get dentry for @sd.  Only return a dentry if one currently
+ *	exists.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	Pointer to found dentry on success, NULL on failure.
+ */
+static struct dentry *__sysfs_get_dentry(struct super_block *sb,
+					 struct sysfs_dirent *sd)
+{
+	struct inode *inode;
+	struct dentry *dentry = NULL;
+
+	inode = ilookup5_nowait(sysfs_sb, sd->s_ino, sysfs_ilookup_test, sd);
+	if (inode && !(inode->i_state & I_NEW)) {
+		struct dentry *alias;
+		spin_lock(&dcache_lock);
+		list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+			if (!IS_ROOT(alias) && d_unhashed(alias))
+				continue;
+			if (alias->d_sb != sb)
+				continue;
+			dentry = alias;
+			dget_locked(dentry);
+			break;
+		}
+		spin_unlock(&dcache_lock);
+	}
+	iput(inode);
+	return dentry;
+}
+
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 {
 	struct sysfs_dirent *sd = kobj->sd;


Patches currently in gregkh-2.6 which might be from gregkh@suse.de are

.git/logs/refs/heads/master
.git/logs/refs/heads/origin
.git/logs/refs/remotes/aria/master
.git/logs/refs/remotes/aria/origin
.git/logs/HEAD
bad/pci-domain/pci-device-ensure-sysdata-initialised.patch
bad/pci-domain/pci-fix-the-x86-pci-domain-support-fix.patch
bad/pci-domain/x86-pci-domain-support-struct-pci_sysdata.patch
bad/pci-domain/x86-pci-domain-support-a-humble-fix.patch
bad/pci-domain/x86-pci-domain-support-the-meat.patch
bad/relayfs/relay-consolidate-relayfs-core-into-kernel-relay.c.patch
bad/relayfs/relay-relay-header-cleanup.patch
bad/relayfs/sysfs-add-__attr_relay-helper-for-relay-attributes.patch
bad/relayfs/sysfs-relay-channel-buffers-as-sysfs-attributes.patch
bad/usbip/usb-usbip-more-dead-code-fix.patch
bad/usbip/usb-usbip-build-fix.patch
bad/usbip/usb-usbip-warning-fixes.patch
bad/ndevfs.patch
bad/driver-sample.sh.patch
bad/driver-model-convert-driver-model-to-mutexes.patch
bad/gpl_future-test.patch
bad/gregkh-debugfs_example.patch
bad/i2c-device-id-lm75.patch
bad/speakup-kconfig-fix.patch
bad/speakup-build-fix.patch
bad/pci-test-that-drivers-properly-call-pci_set_master.patch
bad/pci-use-new-multi-phase-suspend-infrastructure.patch
bad/speakup-core.patch
bad/uio.patch
bad/usbfs2.patch
bad/no-more-non-gpl-modules.patch
bad/usb-serial-serqt_usb.patch
bad/spi-device.patch
bad/ata_piix-multithread.patch
bad/uio-irq.patch
bad/sysfs-crash-debugging.patch
bad/pci-dynamic-id-cleanup.patch
bad/pci-piggy-bus.patch
bad/input-device_type.patch
bad/usb-iphone-charge.patch
bad/sysfs-test.patch
bad/ohci-fix-toggle-bit-desynchronization-when-canceling-urbs.patch
bad/ldp/dvb-add-firesat-driver.patch
bad/ldp/video-add-the-go7007-driver.patch
bad/ldp/framebuffer-add-the-via-framebuffer-driver.patch
bad/ldp/net-add-alacritech-slicoss-driver.patch
bad/ldp/aectc-add-the-aectc-driver.patch
bad/ldp/me4000-firmware-file.patch
bad/ldp/novfs-add-the-novell-filesystem-client-kernel-module.patch
bad/ldp/net-add-et131x-driver.patch
bad/ldp/oms-add-oms-maxp-driver.patch
bad/ldp/me4000-add-pci-data-collection-driver.patch
bad/ldp/usb-add-usb-test-and-measurement-class-driver.patch
bad/ldp/kolter_1616-add-kolter_1616-pci-i-o-driver.patch
bad/ldp.next/usb-add-option-hso-driver.patch
bad/ldp.next/usb-add-sensoray-2255-v4l-driver.patch
bad/ldp.next/input-add-appleir-driver.patch
gregkh/gkh-version.patch
gregkh/sysrq-u-laptop.patch
usb/usb-gotemp.patch
usb/hso-fix-oops-in-read-write-callbacks.patch
usb/hso-fix-refcounting-on-the-ttyhsx-devices.patch
usb/usb-hso-make-tty_operations-const.patch
usb/usb-hso-minor-fixes-due-to-code-review.patch
usb/usb-add-config_usb_debug_messages-and-usb_dbg.patch
usb/usb-convert-the-usb-core-code-to-use-usb_dbg.patch
usb/usb-remove-config_usb_debug.patch
usb/usb-convert-the-usb-host-controller-code-to-use-usb_dbg.patch
usb/usb-remove-warn-macro-from-usb.h.patch
usb/usb-remove-info-macro-from-usb.h.patch
usb/hso-icon-322-detection-fix.patch
usb/hso-dev_kfree_skb-crash-fix.patch
usb/usb-add-new-pm-callback-methods-for-usb.patch
usb/drivers-usb-class-usblp.c-adjust-error-handling-code.patch
usb/usb-kill-urbs-permanently.patch
usb/usb-extend-poisoning-to-anchors.patch
usb/ub-remove-sg_stat.patch
usb/usb-added-driver-for-a-delcom-usb-7-segment-led-display.patch
usb/usb-add-udev-argument-to-interface-suspend-resume-functions.patch
usb/usb-defer-set-interface-for-suspended-devices.patch
usb/usb-don-t-rebind-before-complete-callback.patch
usb/usb-gadget-dummy_hcd-implement-set_wedge.patch
usb/usb-gadget-kconfig-cleanup.patch
usb/usb-gadget-net2280-implement-set_wedge.patch
usb/usb-let-some-usb-host-controllers-get-irq-flags-from-resource.patch
usb/usb-removed-unused-include-version.h.patch
usb.current/usb-cdc-acm-quirk-for-conexant-cx93010-usb-modem.patch
usb.current/usb-fix-bug-in-usb_unlink_anchored_urbs.patch
usb.current/usb-fix-pxa27x_udc-usb-speed-handling.patch
usb.current/usb-isp1760-fixed-trivial-math-in-comment.patch
usb.current/usb-serial-option-support-hsdpa-modem-a2502.patch
HOWTO
driver-core/sysfs-crash-debugging.patch
driver-core/warn-when-statically-allocated-kobjects-are-used.patch
driver-core/usb-gadget-make-gadget_core.ko.patch
driver-core/net-convert-the-phy_device-file-to-use-bus_find_device_by_name.patch
driver-core/s390-bus_id-dev_set_name-for-css-and-ccw-busses.patch
driver-core/driver-core-make-struct-platform_pm_ops-static.patch
driver-core/sysfs-support-sysfs_notify-from-atomic-context-with-new-sysfs_notify_dirent.patch
driver-core/driver-core-basic-infrastructure-for-per-module-dynamic-debug-messages.patch
driver-core/usb-gadget-move-f_acm.c-and-u_serial.c-gadget_acm_core.ko.patch
driver-core/usb-gadget-move-f_ecm.c-to-gadget_ecm_core.ko.patch
driver-core/usb-gadget-move-u_ether.c-to-gadget_ether_core.ko.patch
driver-core/usb-gadget-move-library-files-into-g_cdc.ko.patch
driver-core/usb-gadget-move-library-files-into-g_ether.ko.patch
driver-core/usb-gadget-move-library-files-into-g_file_storage.ko.patch
driver-core/usb-gadget-move-library-files-into-g_midi.ko.patch
driver-core/usb-gadget-move-library-files-into-g_printer.ko.patch
driver-core/usb-gadget-move-library-files-into-g_serial-ko.patch
driver-core/usb-gadget-move-library-files-into-g_zero.ko.patch
driver-core/device-create-block-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-char-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-ide-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-ieee1394-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-infiniband-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-misc-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-net-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-remove-device_create_drvdata.patch
driver-core/device-create-s390-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-scsi-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-sound-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-usb-convert-device_create_drvdata-to-device_create.patch
driver-core/device-create-video-convert-device_create_drvdata-to-device_create.patch
driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/sysfs-implement-__sysfs_get_dentry.patch
driver-core/sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch
driver-core/sysfs-sysfs_get_dentry-add-a-sb-parameter.patch
driver-core/sysfs-rename-support-multiple-superblocks.patch
driver-core/sysfs-support-for-preventing-unmounts.patch
driver-core/sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch
driver-core/driver-core-convert-to-new-device-api-to-allow-names-longer-than-20-chars.patch
driver-core/driver-core-lguest-convert-to-new-device-api-to-allow-names-longer-than-20-chars.patch
driver-core/driver-core-prepare-for-removal-of-20-char-limit-from-struct-device.patch
driver-core/s390-bus_id-dev_set_name-changes.patch
driver-core/s390-more-bus_id-dev_name-conversions.patch
driver-core/s390-use-s390_root_dev_-in-kvm_virtio.patch
driver-core/s390-bus_id-dev_name-conversions.patch
driver-core/driver-core-provide-a-dev_set_name-that-handles-names-longer-than-20-chars.patch
pending/perfmon-fix-up-some-static-kobject-usages.patch
pending/kobject-change-sys-kernel-uids-to-not-use-a-kset.patch
pending/kobjects-hook-them-up-to-the-debugobjects-infrastructure.patch
pending/firmware-add-kconfig-and-makefile-to-build-the-firmware-samples.patch
driver-core.current/dev_printk-constify-the-dev-argument.patch
driver-core.current/drivers-base-driver.c-remove-unused-to_dev-macro.patch
driver-core.current/japanese-translation-of-documentation-submitchecklist.patch
driver-core.current/kobject-replace-all-occurrences-of-with-instead-of-only-the-first-one.patch
driver-core.current/driver-model-anti-oopsing-medicine.patch
driver-core.current/pm-don-t-skip-device-pm-init-when-config_pm_sleep-isn-t-set-and-config_pm-is-set.patch
driver-core.current/driver-core-add-init_name-to-struct-device.patch
driver-core.current/pm-remove-warn_on-from-device_pm_add.patch
driver-core.current/block-drop-references-taken-by-class_find_device.patch
driver-core.current/block-fix-partial-read-of-proc-partitions-diskstats.patch

patch sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: sysfs: Introduce sysfs_sd_setattr and fix sysfs_chmod

to my gregkh-2.6 tree.  Its filename is

    sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:21:56 2008
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Thu, 03 Jul 2008 18:11:40 -0700
Subject: sysfs: Introduce sysfs_sd_setattr and fix sysfs_chmod
To: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m18wwiihbn.fsf_-_@frodo.ebiederm.org>

From: Eric W. Biederman <ebiederm@xmission.com>


Currently sysfs_chmod calls sys_setattr which in turn calls
inode_change_ok which checks to see if it is ok for the current user
space process to change tha attributes. Since sysfs_chmod_file has
only kernel mode clients denying them permission if user space is the
problem is completely inappropriate.

Therefore factor out sysfs_sd_setattr which does not call
inode_change_ok and modify sysfs_chmod_file to call it.

In addition setting victim_sd->s_mode explicitly in sysfs_chmod_file
is redundant so remove that as well.

Thanks to Tejun Heo <htejun@gmail.com>, and
Daniel Lezcano <dlezcano@fr.ibm.com> for working on this
and spotting this case.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/file.c  |    5 +----
 fs/sysfs/inode.c |   23 ++++++++++++++++-------
 fs/sysfs/sysfs.h |    1 +
 3 files changed, 18 insertions(+), 11 deletions(-)

--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -604,13 +604,10 @@ int sysfs_chmod_file(struct kobject *kob
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 	newattrs.ia_ctime = current_fs_time(inode->i_sb);
-	rc = sysfs_setattr(victim, &newattrs);
+	rc = sysfs_sd_setattr(victim_sd, inode, &newattrs);
 
 	if (rc == 0) {
 		fsnotify_change(victim, newattrs.ia_valid);
-		mutex_lock(&sysfs_mutex);
-		victim_sd->s_mode = newattrs.ia_mode;
-		mutex_unlock(&sysfs_mutex);
 	}
 
 	mutex_unlock(&inode->i_mutex);
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -42,10 +42,9 @@ int __init sysfs_inode_init(void)
 	return bdi_init(&sysfs_backing_dev_info);
 }
 
-int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode,
+			struct iattr * iattr)
 {
-	struct inode * inode = dentry->d_inode;
-	struct sysfs_dirent * sd = dentry->d_fsdata;
 	struct iattr * sd_iattr;
 	unsigned int ia_valid = iattr->ia_valid;
 	int error;
@@ -55,10 +54,6 @@ int sysfs_setattr(struct dentry * dentry
 
 	sd_iattr = sd->s_iattr;
 
-	error = inode_change_ok(inode, iattr);
-	if (error)
-		return error;
-
 	iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
 
 	error = inode_setattr(inode, iattr);
@@ -104,6 +99,20 @@ int sysfs_setattr(struct dentry * dentry
 	return error;
 }
 
+int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode * inode = dentry->d_inode;
+	struct sysfs_dirent * sd = dentry->d_fsdata;
+	int error;
+
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		return error;
+
+	return sysfs_sd_setattr(sd, inode, iattr);
+}
+
+
 static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
 {
 	inode->i_mode = mode;
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -156,6 +156,7 @@ static inline void __sysfs_put(struct sy
  * inode.c
  */
 struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr);
 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
 int sysfs_inode_init(void);


Patches currently in gregkh-2.6 which might be from ebiederm@xmission.com are

driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/sysfs-implement-__sysfs_get_dentry.patch
driver-core/sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch
driver-core/sysfs-sysfs_get_dentry-add-a-sb-parameter.patch
driver-core/sysfs-rename-support-multiple-superblocks.patch
driver-core/sysfs-support-for-preventing-unmounts.patch
driver-core/sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch

patch sysfs-rename-support-multiple-superblocks.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: sysfs: Rename Support multiple superblocks

to my gregkh-2.6 tree.  Its filename is

    sysfs-rename-support-multiple-superblocks.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:11:52 2008
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Thu, 03 Jul 2008 18:10:05 -0700
Subject: sysfs: Rename Support multiple superblocks
To: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m1d4luihea.fsf_-_@frodo.ebiederm.org>

From: Eric W. Biederman <ebiederm@xmission.com>


This patch modifies the sysfs_rename_dir and sysfs_move_dir routines
to support multiple sysfs dentry tries rooted in different
sysfs superblocks.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/dir.c |  195 ++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 137 insertions(+), 58 deletions(-)

--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -834,43 +834,113 @@ static struct dentry *__sysfs_get_dentry
 	return dentry;
 }
 
+struct sysfs_rename_struct {
+	struct list_head list;
+	struct dentry *old_dentry;
+	struct dentry *new_dentry;
+	struct dentry *old_parent;
+	struct dentry *new_parent;
+};
+
+static void post_rename(struct list_head *head)
+{
+	struct sysfs_rename_struct *srs;
+	while (!list_empty(head)) {
+		srs = list_entry(head->next, struct sysfs_rename_struct, list);
+		dput(srs->old_dentry);
+		dput(srs->new_dentry);
+		dput(srs->old_parent);
+		dput(srs->new_parent);
+		list_del(&srs->list);
+		kfree(srs);
+	}
+}
+
+static int prep_rename(struct list_head *head,
+	struct sysfs_dirent *sd, struct sysfs_dirent *new_parent_sd,
+	const char *name)
+{
+	struct sysfs_rename_struct *srs;
+	struct super_block *sb;
+	struct dentry *dentry;
+	int error;
+
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		dentry = sysfs_get_dentry(sb, sd);
+		if (dentry == ERR_PTR(-EXDEV))
+			continue;
+		if (IS_ERR(dentry)) {
+			error = PTR_ERR(dentry);
+			goto err_out;
+		}
+
+		srs = kzalloc(sizeof(*srs), GFP_KERNEL);
+		if (!srs) {
+			error = -ENOMEM;
+			dput(dentry);
+			goto err_out;
+		}
+
+		INIT_LIST_HEAD(&srs->list);
+		list_add(head, &srs->list);
+		srs->old_dentry = dentry;
+		srs->old_parent = dget(dentry->d_parent);
+
+		dentry = sysfs_get_dentry(sb, new_parent_sd);
+		if (IS_ERR(dentry)) {
+			error = PTR_ERR(dentry);
+			goto err_out;
+		}
+		srs->new_parent = dentry;
+
+		error = -ENOMEM;
+		dentry = d_alloc_name(srs->new_parent, name);
+		if (!dentry)
+			goto err_out;
+		srs->new_dentry = dentry;
+	}
+	return 0;
+
+err_out:
+	post_rename(head);
+	return error;
+}
+
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 {
 	struct sysfs_dirent *sd = kobj->sd;
-	struct dentry *parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
+	struct list_head todo;
+	struct sysfs_rename_struct *srs;
+	struct inode *parent_inode = NULL;
 	const char *dup_name = NULL;
 	int error;
 
+	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 
 	error = 0;
 	if (strcmp(sd->s_name, new_name) == 0)
 		goto out;	/* nothing to rename */
 
-	/* get the original dentry */
-	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
-	}
+	sysfs_grab_supers();
+	error = prep_rename(&todo, sd, sd->s_parent, new_name);
+	if (error)
+		goto out_release;
 
-	parent = old_dentry->d_parent;
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	parent_inode = sysfs_get_inode(sd->s_parent);
+	mutex_unlock(&sysfs_mutex);
+	if (!parent_inode)
+		goto out_release;
 
-	/* lock parent and get dentry for new name */
-	mutex_lock(&parent->d_inode->i_mutex);
+	mutex_lock(&parent_inode->i_mutex);
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
 	if (sysfs_find_dirent(sd->s_parent, new_name))
 		goto out_unlock;
 
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(parent, new_name);
-	if (!new_dentry)
-		goto out_unlock;
-
 	/* rename sysfs_dirent */
 	error = -ENOMEM;
 	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
@@ -881,17 +951,21 @@ int sysfs_rename_dir(struct kobject * ko
 	sd->s_name = new_name;
 
 	/* rename */
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
+	list_for_each_entry(srs, &todo, list) {
+		d_add(srs->new_dentry, NULL);
+		d_move(srs->old_dentry, srs->new_dentry);
+	}
 
 	error = 0;
- out_unlock:
+out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&parent->d_inode->i_mutex);
+	mutex_unlock(&parent_inode->i_mutex);
 	kfree(dup_name);
-	dput(old_dentry);
-	dput(new_dentry);
- out:
+out_release:
+	iput(parent_inode);
+	post_rename(&todo);
+	sysfs_release_supers();
+out:
 	mutex_unlock(&sysfs_rename_mutex);
 	return error;
 }
@@ -900,10 +974,12 @@ int sysfs_move_dir(struct kobject *kobj,
 {
 	struct sysfs_dirent *sd = kobj->sd;
 	struct sysfs_dirent *new_parent_sd;
-	struct dentry *old_parent, *new_parent = NULL;
-	struct dentry *old_dentry = NULL, *new_dentry = NULL;
+	struct list_head todo;
+	struct sysfs_rename_struct *srs;
+	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	int error;
 
+	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 	BUG_ON(!sd->s_parent);
 	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
@@ -912,26 +988,29 @@ int sysfs_move_dir(struct kobject *kobj,
 	if (sd->s_parent == new_parent_sd)
 		goto out;	/* nothing to move */
 
-	/* get dentries */
-	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
-	if (IS_ERR(old_dentry)) {
-		error = PTR_ERR(old_dentry);
-		old_dentry = NULL;
-		goto out;
-	}
-	old_parent = old_dentry->d_parent;
-
-	new_parent = sysfs_get_dentry(sysfs_sb, new_parent_sd);
-	if (IS_ERR(new_parent)) {
-		error = PTR_ERR(new_parent);
-		new_parent = NULL;
-		goto out;
-	}
+	sysfs_grab_supers();
+	error = prep_rename(&todo, sd, new_parent_sd, sd->s_name);
+	if (error)
+		goto out_release;
+
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	old_parent_inode = sysfs_get_inode(sd->s_parent);
+	mutex_unlock(&sysfs_mutex);
+	if (!old_parent_inode)
+		goto out_release;
+
+	error = -ENOMEM;
+	mutex_lock(&sysfs_mutex);
+	new_parent_inode = sysfs_get_inode(new_parent_sd);
+	mutex_unlock(&sysfs_mutex);
+	if (!new_parent_inode)
+		goto out_release;
 
 again:
-	mutex_lock(&old_parent->d_inode->i_mutex);
-	if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
-		mutex_unlock(&old_parent->d_inode->i_mutex);
+	mutex_lock(&old_parent_inode->i_mutex);
+	if (!mutex_trylock(&new_parent_inode->i_mutex)) {
+		mutex_unlock(&old_parent_inode->i_mutex);
 		goto again;
 	}
 	mutex_lock(&sysfs_mutex);
@@ -940,14 +1019,11 @@ again:
 	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
 		goto out_unlock;
 
-	error = -ENOMEM;
-	new_dentry = d_alloc_name(new_parent, sd->s_name);
-	if (!new_dentry)
-		goto out_unlock;
-
 	error = 0;
-	d_add(new_dentry, NULL);
-	d_move(old_dentry, new_dentry);
+	list_for_each_entry(srs, &todo, list) {
+		d_add(srs->new_dentry, NULL);
+		d_move(srs->old_dentry, srs->new_dentry);
+	}
 
 	/* Remove from old parent's list and insert into new parent's list. */
 	sysfs_unlink_sibling(sd);
@@ -956,14 +1032,17 @@ again:
 	sd->s_parent = new_parent_sd;
 	sysfs_link_sibling(sd);
 
- out_unlock:
+out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&new_parent->d_inode->i_mutex);
-	mutex_unlock(&old_parent->d_inode->i_mutex);
- out:
-	dput(new_parent);
-	dput(old_dentry);
-	dput(new_dentry);
+	mutex_unlock(&new_parent_inode->i_mutex);
+	mutex_unlock(&old_parent_inode->i_mutex);
+
+out_release:
+	iput(new_parent_inode);
+	iput(old_parent_inode);
+	post_rename(&todo);
+	sysfs_release_supers();
+out:
 	mutex_unlock(&sysfs_rename_mutex);
 	return error;
 }


Patches currently in gregkh-2.6 which might be from ebiederm@xmission.com are

driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/sysfs-implement-__sysfs_get_dentry.patch
driver-core/sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch
driver-core/sysfs-sysfs_get_dentry-add-a-sb-parameter.patch
driver-core/sysfs-rename-support-multiple-superblocks.patch
driver-core/sysfs-support-for-preventing-unmounts.patch
driver-core/sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch

patch sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: sysfs: sysfs_chmod_file handle multiple superblocks

to my gregkh-2.6 tree.  Its filename is

    sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:21:56 2008
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Thu, 03 Jul 2008 18:13:05 -0700
Subject: sysfs: sysfs_chmod_file handle multiple superblocks
To: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m14p76ih9a.fsf_-_@frodo.ebiederm.org>


From: Eric W. Biederman <ebiederm@xmission.com>

Teach sysfs_chmod_file how to handle multiple sysfs superblocks.
Since we only have one inode per sd the only thing we have to deal
with is multiple dentries for sending fs notifications.  This might
dup the inode notifications oh well.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/file.c |   39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -578,8 +578,8 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_grou
 int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 {
 	struct sysfs_dirent *victim_sd = NULL;
-	struct dentry *victim = NULL;
-	struct inode * inode;
+	struct super_block *sb;
+	struct inode * inode = NULL;
 	struct iattr newattrs;
 	int rc;
 
@@ -588,31 +588,42 @@ int sysfs_chmod_file(struct kobject *kob
 	if (!victim_sd)
 		goto out;
 
-	mutex_lock(&sysfs_rename_mutex);
-	victim = sysfs_get_dentry(sysfs_sb, victim_sd);
-	mutex_unlock(&sysfs_rename_mutex);
-	if (IS_ERR(victim)) {
-		rc = PTR_ERR(victim);
-		victim = NULL;
-		goto out;
-	}
-
-	inode = victim->d_inode;
+	rc = -ENOENT;
+	mutex_lock(&sysfs_mutex);
+	inode = sysfs_get_inode(victim_sd);
+	mutex_unlock(&sysfs_mutex);
+	if (!inode)
+ 		goto out;
 
+	mutex_lock(&sysfs_rename_mutex);
+	sysfs_grab_supers();
 	mutex_lock(&inode->i_mutex);
 
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 	newattrs.ia_ctime = current_fs_time(inode->i_sb);
 	rc = sysfs_sd_setattr(victim_sd, inode, &newattrs);
+	if (rc)
+		goto out_unlock;
+
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		/* Ignore it when the dentry does not exist on the
+		 * target superblock.
+		 */
+		struct dentry *	victim = sysfs_get_dentry(sb, victim_sd);
+		if (IS_ERR(victim))
+			continue;
 
-	if (rc == 0) {
 		fsnotify_change(victim, newattrs.ia_valid);
+		dput(victim);
 	}
 
+ out_unlock:
 	mutex_unlock(&inode->i_mutex);
+	sysfs_release_supers();
+	mutex_unlock(&sysfs_rename_mutex);
  out:
-	dput(victim);
+	iput(inode);
 	sysfs_put(victim_sd);
 	return rc;
 }


Patches currently in gregkh-2.6 which might be from ebiederm@xmission.com are

driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/sysfs-implement-__sysfs_get_dentry.patch
driver-core/sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch
driver-core/sysfs-sysfs_get_dentry-add-a-sb-parameter.patch
driver-core/sysfs-rename-support-multiple-superblocks.patch
driver-core/sysfs-support-for-preventing-unmounts.patch
driver-core/sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch

patch sysfs-sysfs_get_dentry-add-a-sb-parameter.patch added to gregkh-2.6 tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    Subject: sysfs: sysfs_get_dentry add a sb parameter

to my gregkh-2.6 tree.  Its filename is

    sysfs-sysfs_get_dentry-add-a-sb-parameter.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/


>From ebiederm@xmission.com Thu Jul  3 18:11:49 2008
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Thu, 03 Jul 2008 18:08:02 -0700
Subject: sysfs: sysfs_get_dentry add a sb parameter
To: Greg Kroah-Hartman <gregkh@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <htejun@gmail.com>, Daniel Lezcano <dlezcano@fr.ibm.com>, linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>, Linux Containers <containers@lists.osdl.org>, Benjamin Thery <benjamin.thery@bull.net>, <netdev@vger.kernel.org>
Message-ID: <m1lk0iihhp.fsf_-_@frodo.ebiederm.org>

From: Eric W. Biederman <ebiederm@xmission.com>


In preparation for multiple mounts of sysfs add a superblock parameter to
sysfs_get_dentry.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/sysfs/dir.c   |   12 +++++++-----
 fs/sysfs/file.c  |    2 +-
 fs/sysfs/sysfs.h |    3 ++-
 3 files changed, 10 insertions(+), 7 deletions(-)

--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -85,6 +85,7 @@ static void sysfs_unlink_sibling(struct 
 
 /**
  *	sysfs_get_dentry - get dentry for the given sysfs_dirent
+ *	@sb: superblock of the dentry to return
  *	@sd: sysfs_dirent of interest
  *
  *	Get dentry for @sd.  Dentry is looked up if currently not
@@ -97,9 +98,10 @@ static void sysfs_unlink_sibling(struct 
  *	RETURNS:
  *	Pointer to found dentry on success, ERR_PTR() value on error.
  */
-struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
+struct dentry *sysfs_get_dentry(struct super_block *sb,
+				struct sysfs_dirent *sd)
 {
-	struct dentry *dentry = dget(sysfs_sb->s_root);
+	struct dentry *dentry = dget(sb->s_root);
 
 	while (dentry->d_fsdata != sd) {
 		struct sysfs_dirent *cur;
@@ -808,7 +810,7 @@ int sysfs_rename_dir(struct kobject * ko
 		goto out;	/* nothing to rename */
 
 	/* get the original dentry */
-	old_dentry = sysfs_get_dentry(sd);
+	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
 	if (IS_ERR(old_dentry)) {
 		error = PTR_ERR(old_dentry);
 		old_dentry = NULL;
@@ -872,7 +874,7 @@ int sysfs_move_dir(struct kobject *kobj,
 		goto out;	/* nothing to move */
 
 	/* get dentries */
-	old_dentry = sysfs_get_dentry(sd);
+	old_dentry = sysfs_get_dentry(sysfs_sb, sd);
 	if (IS_ERR(old_dentry)) {
 		error = PTR_ERR(old_dentry);
 		old_dentry = NULL;
@@ -880,7 +882,7 @@ int sysfs_move_dir(struct kobject *kobj,
 	}
 	old_parent = old_dentry->d_parent;
 
-	new_parent = sysfs_get_dentry(new_parent_sd);
+	new_parent = sysfs_get_dentry(sysfs_sb, new_parent_sd);
 	if (IS_ERR(new_parent)) {
 		error = PTR_ERR(new_parent);
 		new_parent = NULL;
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -589,7 +589,7 @@ int sysfs_chmod_file(struct kobject *kob
 		goto out;
 
 	mutex_lock(&sysfs_rename_mutex);
-	victim = sysfs_get_dentry(victim_sd);
+	victim = sysfs_get_dentry(sysfs_sb, victim_sd);
 	mutex_unlock(&sysfs_rename_mutex);
 	if (IS_ERR(victim)) {
 		rc = PTR_ERR(victim);
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -112,7 +112,8 @@ extern spinlock_t sysfs_assoc_lock;
 extern const struct file_operations sysfs_dir_operations;
 extern const struct inode_operations sysfs_dir_inode_operations;
 
-struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);
+struct dentry *sysfs_get_dentry(struct super_block *sb,
+				struct sysfs_dirent *sd);
 struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd);
 void sysfs_put_active_two(struct sysfs_dirent *sd);
 void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,


Patches currently in gregkh-2.6 which might be from ebiederm@xmission.com are

driver-core/kobject-fix-kobject_rename-and-config_sysfs.patch
driver-core/kobject-cleanup-kobject_rename-and-config_sysfs.patch
driver-core/sysfs-implement-__sysfs_get_dentry.patch
driver-core/sysfs-introduce-sysfs_sd_setattr-and-fix-sysfs_chmod.patch
driver-core/sysfs-sysfs_get_dentry-add-a-sb-parameter.patch
driver-core/sysfs-rename-support-multiple-superblocks.patch
driver-core/sysfs-support-for-preventing-unmounts.patch
driver-core/sysfs-sysfs_chmod_file-handle-multiple-superblocks.patch

Re: [PATCH 09/15] sysfs: Implement sysfs tagged directory support.

[Greg KH]

On Thu, Jul 03, 2008 at 06:16:08PM -0700, Eric W. Biederman wrote:
> 
> The problem.  When implementing a network namespace I need to be able
> to have multiple network devices with the same name.  Currently this
> is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
> potentially a few other directories of the form /sys/ ... /net/*.

<snip>

I applied the patches up to here (well, patch 8 was no longer needed at
all anymore), but this one doesn't apply at all.

Care to respin these last few patches?

thanks,

greg k-h

Re: [PATCH 09/15] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

Greg KH <greg@kroah.com> writes:

> On Thu, Jul 03, 2008 at 06:16:08PM -0700, Eric W. Biederman wrote:
>> 
>> The problem.  When implementing a network namespace I need to be able
>> to have multiple network devices with the same name.  Currently this
>> is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
>> potentially a few other directories of the form /sys/ ... /net/*.
>
> <snip>
>
> I applied the patches up to here (well, patch 8 was no longer needed at
> all anymore), but this one doesn't apply at all.
>
> Care to respin these last few patches?

Sounds like a plan.

Looks like we are just talking about the driver core patches so while a pain
it actually should not be too hard.

I will get a copy of your gregkh tree from kernel.org tomorrow and see
what I can do.

Eric

[PATCH 0/8] sysfs namespace support

[Eric W. Biederman]

Greg the first 4 patches are the rest of the infrastructure.
Everything rebased quite nicely.  All of the conflicts appear
to have been false positives.

With the addition of sysfs_rename_link sysfs_create_link_nowarn
is never called so we can remove it.

I'm not really certain whose tree the last netns or the user
namespace changes should live in, but I am continuing to
have those patches in this patchset for completeness.

Eric W. Biederman (7):
1      sysfs: Implement sysfs tagged directory support.
2      sysfs: Merge sysfs_rename_dir and sysfs_move_dir
3      sysfs: Implement sysfs_delete_link and sysfs_rename_link
4      driver core: Implement tagged directory support for device classes.

5      sysfs: Remove sysfs_create_link_nowarn

6      Revert "netns: Fix device renaming for sysfs"
7      netns: Enable tagging for net_class directories in sysfs

Serge Hallyn (1):
8      sysfs: user namespaces: fix bug with clone(CLONE_NEWUSER) with fairsched

[PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

The problem.  When implementing a network namespace I need to be able
to have multiple network devices with the same name.  Currently this
is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
potentially a few other directories of the form /sys/ ... /net/*.

What this patch does is to add an additional tag field to the
sysfs dirent structure.  For directories that should show different
contents depending on the context such as /sys/class/net/, and
/sys/devices/virtual/net/ this tag field is used to specify the
context in which those directories should be visible.  Effectively
this is the same as creating multiple distinct directories with
the same name but internally to sysfs the result is nicer.

I am calling the concept of a single directory that looks like multiple
directories all at the same path in the filesystem tagged directories.

For the networking namespace the set of directories whose contents I need
to filter with tags can depend on the presence or absence of hotplug
hardware or which modules are currently loaded.  Which means I need
a simple race free way to setup those directories as tagged.

To achieve a reace free design all tagged directories are created
and managed by sysfs itself.

Users of this interface:
- define a type in the sysfs_tag_type enumeration.
- call sysfs_register_tag_types with the type and it's operations
- call sysfs_make_tagged_dir with the tag type on directories
  to be managed by this tag type
- sysfs_exit_tag when an individual tag is no longer valid

- Implement mount_tag() which returns the tag of the calling process
  so we can attach it to a sysfs superblock.
- Implement ktype.sysfs_tag() which returns the tag of a syfs kobject.

Everything else is left up to sysfs and the driver layer.

For the network namespace mount_tag and sysfs_tag are essentially
one line functions, and look to remain that.

Tags are currently represented a const void * pointers as that is
both generic, prevides enough information for equality comparisons,
and is trivial to create for current users, as it is just the
existing namespace pointer.

The work needed in sysfs is more extensive.  At each directory
or symlink creating I need to check if the directory it is being
created in is a tagged directory and if so generate the appropriate
tag to place on the sysfs_dirent.  Likewise at each symlink or
directory removal I need to check if the sysfs directory it is
being removed from is a tagged directory and if so figure out
which tag goes along with the name I am deleting.

Currently only directories which hold kobjects, and
symlinks are supported.  There is not enough information
in the current file attribute interfaces to give us anything
to discriminate on which makes it useless, and there are
no potential users which makes it an uninteresting problem
to solve.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
---
 fs/sysfs/bin.c          |    2 +-
 fs/sysfs/dir.c          |  139 ++++++++++++++++++++++++++++++++++++++++++-----
 fs/sysfs/file.c         |   11 +++--
 fs/sysfs/group.c        |    4 +-
 fs/sysfs/inode.c        |    7 ++-
 fs/sysfs/mount.c        |  115 +++++++++++++++++++++++++++++++++++++--
 fs/sysfs/symlink.c      |    2 +-
 fs/sysfs/sysfs.h        |   19 ++++++-
 include/linux/kobject.h |    1 +
 include/linux/sysfs.h   |   31 +++++++++++
 10 files changed, 298 insertions(+), 33 deletions(-)

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index 006fc64..86e1128 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -252,7 +252,7 @@ int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 
 void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
 {
-	sysfs_hash_and_remove(kobj->sd, attr->attr.name);
+	sysfs_hash_and_remove(kobj, kobj->sd, attr->attr.name);
 }
 
 EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 4ffcfd2..dec7586 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -30,6 +30,30 @@ DEFINE_SPINLOCK(sysfs_assoc_lock);
 static DEFINE_SPINLOCK(sysfs_ino_lock);
 static DEFINE_IDA(sysfs_ino_ida);
 
+static const void *sysfs_creation_tag(struct sysfs_dirent *parent_sd,
+				      struct sysfs_dirent *sd)
+{
+	const void *tag = NULL;
+
+	if (sysfs_tag_type(parent_sd)) {
+		struct kobject *kobj;
+		switch (sysfs_type(sd)) {
+		case SYSFS_DIR:
+			kobj = sd->s_dir.kobj;
+			break;
+		case SYSFS_KOBJ_LINK:
+			kobj = sd->s_symlink.target_sd->s_dir.kobj;
+			break;
+		default:
+			BUG();
+		}
+		tag = kobj->ktype->sysfs_tag(kobj);
+		/* NULL tags are reserved for internal use */
+		BUG_ON(tag == NULL);
+	}
+	return tag;
+}
+
 /**
  *	sysfs_link_sibling - link sysfs_dirent into sibling list
  *	@sd: sysfs_dirent of interest
@@ -101,8 +125,19 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
 struct dentry *sysfs_get_dentry(struct super_block *sb,
 				struct sysfs_dirent *sd)
 {
-	struct dentry *dentry = dget(sb->s_root);
+	struct dentry *dentry;
+
+	/* Bail if this sd won't show up in this superblock */
+	if (sd->s_parent) {
+		enum sysfs_tag_type type;
+		const void *tag;
+		type = sysfs_tag_type(sd->s_parent);
+		tag = sysfs_info(sb)->tag[type];
+		if (sd->s_tag != tag)
+			return ERR_PTR(-EXDEV);
+	}
 
+	dentry = dget(sb->s_root);
 	while (dentry->d_fsdata != sd) {
 		struct sysfs_dirent *cur;
 		struct dentry *parent;
@@ -421,10 +456,15 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
  */
 int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
 {
-	if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
+	const void *tag = NULL;
+
+	tag = sysfs_creation_tag(acxt->parent_sd, sd);
+
+	if (sysfs_find_dirent(acxt->parent_sd, tag, sd->s_name))
 		return -EEXIST;
 
 	sd->s_parent = sysfs_get(acxt->parent_sd);
+	sd->s_tag = tag;
 
 	if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
 		inc_nlink(acxt->parent_inode);
@@ -602,13 +642,17 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
  *	Pointer to sysfs_dirent if found, NULL if not.
  */
 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
+				       const void *tag,
 				       const unsigned char *name)
 {
 	struct sysfs_dirent *sd;
 
-	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
+	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
+		if (sd->s_tag != tag)
+			continue;
 		if (!strcmp(sd->s_name, name))
 			return sd;
+	}
 	return NULL;
 }
 
@@ -632,7 +676,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 	struct sysfs_dirent *sd;
 
 	mutex_lock(&sysfs_mutex);
-	sd = sysfs_find_dirent(parent_sd, name);
+	sd = sysfs_find_dirent(parent_sd, NULL, name);
 	sysfs_get(sd);
 	mutex_unlock(&sysfs_mutex);
 
@@ -699,13 +743,18 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
 				struct nameidata *nd)
 {
 	struct dentry *ret = NULL;
-	struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
+	struct dentry *parent = dentry->d_parent;
+	struct sysfs_dirent *parent_sd = parent->d_fsdata;
 	struct sysfs_dirent *sd;
 	struct inode *inode;
+	enum sysfs_tag_type type;
+	const void *tag;
 
 	mutex_lock(&sysfs_mutex);
 
-	sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
+	type = sysfs_tag_type(parent_sd);
+	tag = sysfs_info(parent->d_sb)->tag[type];
+	sd = sysfs_find_dirent(parent_sd, tag, dentry->d_name.name);
 
 	/* no such entry */
 	if (!sd) {
@@ -913,19 +962,24 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	struct sysfs_rename_struct *srs;
 	struct inode *parent_inode = NULL;
 	const char *dup_name = NULL;
+	const void *old_tag, *tag;
 	int error;
 
 	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
+	old_tag = sd->s_tag;
+	tag = sysfs_creation_tag(sd->s_parent, sd);
 
 	error = 0;
-	if (strcmp(sd->s_name, new_name) == 0)
+	if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
 		goto out;	/* nothing to rename */
 
 	sysfs_grab_supers();
-	error = prep_rename(&todo, sd, sd->s_parent, new_name);
-	if (error)
-		goto out_release;
+	if (old_tag == tag) {
+		error = prep_rename(&todo, sd, sd->s_parent, new_name);
+		if (error)
+			goto out_release;
+	}
 
 	error = -ENOMEM;
 	mutex_lock(&sysfs_mutex);
@@ -938,7 +992,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(sd->s_parent, new_name))
+	if (sysfs_find_dirent(sd->s_parent, tag, new_name))
 		goto out_unlock;
 
 	/* rename sysfs_dirent */
@@ -949,6 +1003,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 
 	dup_name = sd->s_name;
 	sd->s_name = new_name;
+	sd->s_tag = tag;
 
 	/* rename */
 	list_for_each_entry(srs, &todo, list) {
@@ -956,6 +1011,20 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 		d_move(srs->old_dentry, srs->new_dentry);
 	}
 
+	/* If we are moving across superblocks drop the dcache entries */
+	if (old_tag != tag) {
+		struct super_block *sb;
+		struct dentry *dentry;
+		list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+			dentry = __sysfs_get_dentry(sb, sd);
+			if (!dentry)
+				continue;
+			shrink_dcache_parent(dentry);
+			d_drop(dentry);
+			dput(dentry);
+		}
+	}
+
 	error = 0;
 out_unlock:
 	mutex_unlock(&sysfs_mutex);
@@ -978,11 +1047,13 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
 	struct sysfs_rename_struct *srs;
 	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	int error;
+	const void *tag;
 
 	INIT_LIST_HEAD(&todo);
 	mutex_lock(&sysfs_rename_mutex);
 	BUG_ON(!sd->s_parent);
 	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
+	tag = sd->s_tag;
 
 	error = 0;
 	if (sd->s_parent == new_parent_sd)
@@ -1016,7 +1087,7 @@ again:
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
+	if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
 		goto out_unlock;
 
 	error = 0;
@@ -1055,10 +1126,12 @@ static inline unsigned char dt_type(struct sysfs_dirent *sd)
 
 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
-	struct dentry *dentry = filp->f_path.dentry;
-	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
+	struct dentry *parent = filp->f_path.dentry;
+	struct sysfs_dirent *parent_sd = parent->d_fsdata;
 	struct sysfs_dirent *pos;
 	ino_t ino;
+	enum sysfs_tag_type type;
+	const void *tag;
 
 	if (filp->f_pos == 0) {
 		ino = parent_sd->s_ino;
@@ -1076,6 +1149,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 	if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
 		mutex_lock(&sysfs_mutex);
 
+		type = sysfs_tag_type(parent_sd);
+		tag = sysfs_info(parent->d_sb)->tag[type];
+
 		/* Skip the dentries we have already reported */
 		pos = parent_sd->s_dir.children;
 		while (pos && (filp->f_pos > pos->s_ino))
@@ -1085,6 +1161,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 			const char * name;
 			int len;
 
+			if (pos->s_tag != tag)
+				continue;
+
 			name = pos->s_name;
 			len = strlen(name);
 			filp->f_pos = ino = pos->s_ino;
@@ -1105,3 +1184,35 @@ const struct file_operations sysfs_dir_operations = {
 	.read		= generic_read_dir,
 	.readdir	= sysfs_readdir,
 };
+
+/**
+ *	sysfs_make_tagged_dir - Require tags of all the entries in a directory.
+ *	@kobj:	object whose children should be filtered by tags
+ *
+ *	Once tagging has been enabled on a directory the contents
+ *	of the directory become dependent upon context captured when
+ *	sysfs was mounted.
+ */
+int sysfs_make_tagged_dir(struct kobject *kobj, enum sysfs_tag_type type)
+{
+	struct sysfs_dirent *sd;
+	int err;
+
+	err = -ENOENT;
+	sd = kobj->sd;
+
+	mutex_lock(&sysfs_mutex);
+	err = -EINVAL;
+	/* We can only enable tagging when we have a valid tag type
+	 * on empty directories where taggint has not already been
+	 * enabled.
+	 */
+	if ((type > SYSFS_TAG_TYPE_NONE) && (type < SYSFS_TAG_TYPES) &&
+	    tag_ops[type] && !sysfs_tag_type(sd) &&
+	    (sysfs_type(sd) == SYSFS_DIR) && !sd->s_dir.children) {
+		err = 0;
+		sd->s_flags |= (type << SYSFS_TAG_TYPE_SHIFT);
+	}
+	mutex_unlock(&sysfs_mutex);
+	return err;
+}
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 61c3476..091c0de 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -476,9 +476,12 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
 	mutex_lock(&sysfs_mutex);
 
 	if (sd && dir)
-		sd = sysfs_find_dirent(sd, dir);
+		/* Only directories are tagged, so no need to pass
+		 * a tag explicitly.
+		 */
+		sd = sysfs_find_dirent(sd, NULL, dir);
 	if (sd && attr)
-		sd = sysfs_find_dirent(sd, attr);
+		sd = sysfs_find_dirent(sd, NULL, attr);
 	if (sd)
 		sysfs_notify_dirent(sd);
 
@@ -640,7 +643,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file);
 
 void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
 {
-	sysfs_hash_and_remove(kobj->sd, attr->name);
+	sysfs_hash_and_remove(kobj, kobj->sd, attr->name);
 }
 
 
@@ -660,7 +663,7 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
 	else
 		dir_sd = sysfs_get(kobj->sd);
 	if (dir_sd) {
-		sysfs_hash_and_remove(dir_sd, attr->name);
+		sysfs_hash_and_remove(kobj, dir_sd, attr->name);
 		sysfs_put(dir_sd);
 	}
 }
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index fe61194..5fba6f2 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -23,7 +23,7 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 	int i;
 
 	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
-		sysfs_hash_and_remove(dir_sd, (*attr)->name);
+		sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
 }
 
 static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
@@ -39,7 +39,7 @@ static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 		 * visibility.  Do this by first removing then
 		 * re-adding (if required) the file */
 		if (update)
-			sysfs_hash_and_remove(dir_sd, (*attr)->name);
+			sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
 		if (grp->is_visible) {
 			mode = grp->is_visible(kobj, *attr, i);
 			if (!mode)
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 80f8fd4..b5fc78a 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -226,17 +226,20 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
 	return inode;
 }
 
-int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
+int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
+			  const char *name)
 {
 	struct sysfs_addrm_cxt acxt;
 	struct sysfs_dirent *sd;
+	const void *tag;
 
 	if (!dir_sd)
 		return -ENOENT;
 
 	sysfs_addrm_start(&acxt, dir_sd);
+	tag = kobj->sd->s_tag;
 
-	sd = sysfs_find_dirent(dir_sd, name);
+	sd = sysfs_find_dirent(dir_sd, tag, name);
 	if (sd)
 		sysfs_remove_one(&acxt, sd);
 
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 6ebda1a..8f2237a 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -35,12 +35,15 @@ static const struct super_operations sysfs_ops = {
 struct sysfs_dirent sysfs_root = {
 	.s_name		= "",
 	.s_count	= ATOMIC_INIT(1),
-	.s_flags	= SYSFS_DIR,
+	.s_flags	= SYSFS_DIR | (SYSFS_TAG_TYPE_NONE << SYSFS_TAG_TYPE_SHIFT),
 	.s_mode		= S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
 	.s_ino		= 1,
 };
 
-static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
+struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
+
+static int sysfs_fill_super(struct super_block *sb, void *data, int silent,
+	const void *tags[SYSFS_TAG_TYPES])
 {
 	struct sysfs_super_info *info = NULL;
 	struct inode *inode = NULL;
@@ -76,8 +79,10 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_err;
 	}
 	root->d_fsdata = &sysfs_root;
+	root->d_sb = sb;
 	sb->s_root = root;
 	sb->s_fs_info = info;
+	memcpy(info->tag, tags, sizeof(info->tag[0])*SYSFS_TAG_TYPES);
 	return 0;
 
 out_err:
@@ -89,20 +94,74 @@ out_err:
 	return error;
 }
 
+static int sysfs_test_super(struct super_block *sb, void *ptr)
+{
+	const void **tag = ptr;
+	struct sysfs_super_info *info = sysfs_info(sb);
+	enum sysfs_tag_type type;
+	int found = 1;
+
+	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
+		if (info->tag[type] != tag[type]) {
+			found = 0;
+			break;
+		}
+	}
+
+	return found;
+}
+
 static int sysfs_get_sb(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
-	int rc;
+	const void *tag[SYSFS_TAG_TYPES];
+	struct super_block *sb;
+	int error;
+	enum sysfs_tag_type type;
+
+	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
+		tag[type] = NULL;
+		if (!tag_ops[type])
+			continue;
+		tag[type] = tag_ops[type]->mount_tag();
+	}
+
 	mutex_lock(&sysfs_rename_mutex);
-	rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
+	sb = sget(fs_type, sysfs_test_super, set_anon_super, tag);
+	if (IS_ERR(sb)) {
+		error = PTR_ERR(sb);
+		goto out;
+	}
+	if (!sb->s_root) {
+		sb->s_flags = flags;
+		error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0,
+					tag);
+		if (error) {
+			up_write(&sb->s_umount);
+			deactivate_super(sb);
+			goto out;
+		}
+		sb->s_flags |= MS_ACTIVE;
+	}
+	do_remount_sb(sb, flags, data, 0);
+	error = simple_set_mnt(mnt, sb);
+out:
 	mutex_unlock(&sysfs_rename_mutex);
-	return rc;
+	return error;
+}
+
+static void sysfs_kill_sb(struct super_block *sb)
+{
+	struct sysfs_super_info *info = sysfs_info(sb);
+
+	kill_anon_super(sb);
+	kfree(info);
 }
 
 struct file_system_type sysfs_fs_type = {
 	.name		= "sysfs",
 	.get_sb		= sysfs_get_sb,
-	.kill_sb	= kill_anon_super,
+	.kill_sb	= sysfs_kill_sb,
 };
 
 void sysfs_grab_supers(void)
@@ -146,6 +205,50 @@ restart:
 	spin_unlock(&sb_lock);
 }
 
+int sysfs_register_tag_type(enum sysfs_tag_type type, struct sysfs_tag_type_operations *ops)
+{
+	int error;
+
+	mutex_lock(&sysfs_rename_mutex);
+
+	error = -EINVAL;
+	if (type >= SYSFS_TAG_TYPES)
+		goto out;
+
+	error = -EINVAL;
+	if (type <= SYSFS_TAG_TYPE_NONE)
+		goto out;
+
+	error = -EBUSY;
+	if (tag_ops[type])
+		goto out;
+
+	error = 0;
+	tag_ops[type] = ops;
+
+out:
+	mutex_unlock(&sysfs_rename_mutex);
+	return error;
+}
+
+void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
+{
+	/* Allow the tag to go away while sysfs is still mounted. */
+	struct super_block *sb;
+	mutex_lock(&sysfs_rename_mutex);
+	sysfs_grab_supers();
+	mutex_lock(&sysfs_mutex);
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		struct sysfs_super_info *info = sysfs_info(sb);
+		if (info->tag[type] != tag)
+			continue;
+		info->tag[type] = NULL;
+	}
+	mutex_unlock(&sysfs_mutex);
+	sysfs_release_supers();
+	mutex_unlock(&sysfs_rename_mutex);
+}
+
 int __init sysfs_init(void)
 {
 	int err = -ENOMEM;
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index a3ba217..54b2e5f 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -119,7 +119,7 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
 	else
 		parent_sd = kobj->sd;
 
-	sysfs_hash_and_remove(parent_sd, name);
+	sysfs_hash_and_remove(kobj, parent_sd, name);
 }
 
 static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index f0e5ecb..67115ec 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -45,6 +45,7 @@ struct sysfs_dirent {
 	struct sysfs_dirent	*s_sibling;
 	const char		*s_name;
 
+	const void		*s_tag;
 	union {
 		struct sysfs_elem_dir		s_dir;
 		struct sysfs_elem_symlink	s_symlink;
@@ -67,14 +68,22 @@ struct sysfs_dirent {
 #define SYSFS_KOBJ_LINK			0x0008
 #define SYSFS_COPY_NAME			(SYSFS_DIR | SYSFS_KOBJ_LINK)
 
-#define SYSFS_FLAG_MASK			~SYSFS_TYPE_MASK
-#define SYSFS_FLAG_REMOVED		0x0200
+#define SYSFS_TAG_TYPE_MASK		0xff00
+#define SYSFS_TAG_TYPE_SHIFT		8
+
+#define SYSFS_FLAG_MASK			~(SYSFS_TYPE_MASK | SYSFS_TAG_TYPE_MASK)
+#define SYSFS_FLAG_REMOVED		0x020000
 
 static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
 {
 	return sd->s_flags & SYSFS_TYPE_MASK;
 }
 
+static inline enum sysfs_tag_type sysfs_tag_type(struct sysfs_dirent *sd)
+{
+	return (sd->s_flags & SYSFS_TAG_TYPE_MASK) >> SYSFS_TAG_TYPE_SHIFT;
+}
+
 /*
  * Context structure to be used while adding/removing nodes.
  */
@@ -87,6 +96,7 @@ struct sysfs_addrm_cxt {
 
 struct sysfs_super_info {
 	int	grabbed;
+	const void *tag[SYSFS_TAG_TYPES];
 };
 
 #define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
@@ -98,6 +108,7 @@ extern struct sysfs_dirent sysfs_root;
 extern struct super_block *sysfs_sb;
 extern struct kmem_cache *sysfs_dir_cachep;
 extern struct file_system_type sysfs_fs_type;
+extern struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
 
 void sysfs_grab_supers(void);
 void sysfs_release_supers(void);
@@ -124,6 +135,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
 void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
 
 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
+				       const void *tag,
 				       const unsigned char *name);
 struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 				      const unsigned char *name);
@@ -158,7 +170,8 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
 struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
 int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr);
 int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
-int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
+int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
+			  const char *name);
 int sysfs_inode_init(void);
 
 /*
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 5437ac0..beb3573 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -105,6 +105,7 @@ struct kobj_type {
 	void (*release)(struct kobject *kobj);
 	struct sysfs_ops *sysfs_ops;
 	struct attribute **default_attrs;
+	const void *(*sysfs_tag)(struct kobject *kobj);
 };
 
 struct kobj_uevent_env {
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index d8e0230..ba68829 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -80,6 +80,15 @@ struct sysfs_ops {
 
 struct sysfs_dirent;
 
+enum sysfs_tag_type {
+	SYSFS_TAG_TYPE_NONE = 0,
+	SYSFS_TAG_TYPES
+};
+
+struct sysfs_tag_type_operations {
+	const void *(*mount_tag)(void);
+};
+
 #ifdef CONFIG_SYSFS
 
 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
@@ -126,6 +135,12 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
 void sysfs_put(struct sysfs_dirent *sd);
 void sysfs_printk_last_file(void);
+
+int sysfs_make_tagged_dir(struct kobject *, enum sysfs_tag_type tag_type);
+int sysfs_register_tag_type(enum sysfs_tag_type type,
+			    struct sysfs_tag_type_operations *ops);
+void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag);
+
 int __must_check sysfs_init(void);
 
 #else /* CONFIG_SYSFS */
@@ -249,6 +264,22 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
 {
 }
 
+staticn inline int sysfs_make_tagged_dir(struct kobject *kobj,
+						enum sysfs_tag_type tag_type)
+{
+	return 0;
+}
+
+static inline int sysfs_register_tag_type(enum sysfs_tag_type type,
+					struct sysfs_tag_type_operations *ops)
+{
+	return 0;
+}
+
+static inline void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
+{
+}
+
 static inline int __must_check sysfs_init(void)
 {
 	return 0;
-- 
1.5.3.rc6.17.g1911

[PATCH 2/8] sysfs: Merge sysfs_rename_dir and sysfs_move_dir

[Eric W. Biederman]

These two functions do 90% of the same work and it doesn't significantly
obfuscate the function to allow both the parent dir and the name to change
at the same time.  So merge them together to simplify maintenance, and
increase testing.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/dir.c |  121 +++++++++++++++++--------------------------------------
 1 files changed, 38 insertions(+), 83 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index dec7586..a76fb54 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -955,44 +955,57 @@ err_out:
 	return error;
 }
 
-int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
+static int sysfs_mv_dir(struct sysfs_dirent *sd,
+	struct sysfs_dirent *new_parent_sd, const char *new_name)
 {
-	struct sysfs_dirent *sd = kobj->sd;
 	struct list_head todo;
 	struct sysfs_rename_struct *srs;
-	struct inode *parent_inode = NULL;
+	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
 	const char *dup_name = NULL;
 	const void *old_tag, *tag;
 	int error;
 
 	INIT_LIST_HEAD(&todo);
+	BUG_ON(!sd->s_parent);
 	mutex_lock(&sysfs_rename_mutex);
+	if (!new_parent_sd)
+		new_parent_sd = &sysfs_root;
+
 	old_tag = sd->s_tag;
 	tag = sysfs_creation_tag(sd->s_parent, sd);
 
 	error = 0;
-	if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
-		goto out;	/* nothing to rename */
+	if ((sd->s_parent == new_parent_sd) && (old_tag == tag) &&
+	    (strcmp(sd->s_name, new_name) == 0))
+		goto out;	/* nothing to do */
 
 	sysfs_grab_supers();
 	if (old_tag == tag) {
-		error = prep_rename(&todo, sd, sd->s_parent, new_name);
+		error = prep_rename(&todo, sd, new_parent_sd, new_name);
 		if (error)
 			goto out_release;
 	}
 
 	error = -ENOMEM;
 	mutex_lock(&sysfs_mutex);
-	parent_inode = sysfs_get_inode(sd->s_parent);
+	old_parent_inode = sysfs_get_inode(sd->s_parent);
+	new_parent_inode = sysfs_get_inode(new_parent_sd);
 	mutex_unlock(&sysfs_mutex);
-	if (!parent_inode)
+	if (!old_parent_inode || !new_parent_inode)
 		goto out_release;
 
-	mutex_lock(&parent_inode->i_mutex);
+again:
+	mutex_lock(&old_parent_inode->i_mutex);
+	if (old_parent_inode != new_parent_inode) {
+		if (!mutex_trylock(&new_parent_inode->i_mutex)) {
+			mutex_unlock(&old_parent_inode->i_mutex);
+			goto again;
+		}
+	}
 	mutex_lock(&sysfs_mutex);
 
 	error = -EEXIST;
-	if (sysfs_find_dirent(sd->s_parent, tag, new_name))
+	if (sysfs_find_dirent(new_parent_sd, tag, new_name))
 		goto out_unlock;
 
 	/* rename sysfs_dirent */
@@ -1005,7 +1018,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 	sd->s_name = new_name;
 	sd->s_tag = tag;
 
-	/* rename */
+	/* rename dcache entries */
 	list_for_each_entry(srs, &todo, list) {
 		d_add(srs->new_dentry, NULL);
 		d_move(srs->old_dentry, srs->new_dentry);
@@ -1025,77 +1038,6 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 		}
 	}
 
-	error = 0;
-out_unlock:
-	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&parent_inode->i_mutex);
-	kfree(dup_name);
-out_release:
-	iput(parent_inode);
-	post_rename(&todo);
-	sysfs_release_supers();
-out:
-	mutex_unlock(&sysfs_rename_mutex);
-	return error;
-}
-
-int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
-{
-	struct sysfs_dirent *sd = kobj->sd;
-	struct sysfs_dirent *new_parent_sd;
-	struct list_head todo;
-	struct sysfs_rename_struct *srs;
-	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
-	int error;
-	const void *tag;
-
-	INIT_LIST_HEAD(&todo);
-	mutex_lock(&sysfs_rename_mutex);
-	BUG_ON(!sd->s_parent);
-	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
-	tag = sd->s_tag;
-
-	error = 0;
-	if (sd->s_parent == new_parent_sd)
-		goto out;	/* nothing to move */
-
-	sysfs_grab_supers();
-	error = prep_rename(&todo, sd, new_parent_sd, sd->s_name);
-	if (error)
-		goto out_release;
-
-	error = -ENOMEM;
-	mutex_lock(&sysfs_mutex);
-	old_parent_inode = sysfs_get_inode(sd->s_parent);
-	mutex_unlock(&sysfs_mutex);
-	if (!old_parent_inode)
-		goto out_release;
-
-	error = -ENOMEM;
-	mutex_lock(&sysfs_mutex);
-	new_parent_inode = sysfs_get_inode(new_parent_sd);
-	mutex_unlock(&sysfs_mutex);
-	if (!new_parent_inode)
-		goto out_release;
-
-again:
-	mutex_lock(&old_parent_inode->i_mutex);
-	if (!mutex_trylock(&new_parent_inode->i_mutex)) {
-		mutex_unlock(&old_parent_inode->i_mutex);
-		goto again;
-	}
-	mutex_lock(&sysfs_mutex);
-
-	error = -EEXIST;
-	if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
-		goto out_unlock;
-
-	error = 0;
-	list_for_each_entry(srs, &todo, list) {
-		d_add(srs->new_dentry, NULL);
-		d_move(srs->old_dentry, srs->new_dentry);
-	}
-
 	/* Remove from old parent's list and insert into new parent's list. */
 	sysfs_unlink_sibling(sd);
 	sysfs_get(new_parent_sd);
@@ -1103,10 +1045,13 @@ again:
 	sd->s_parent = new_parent_sd;
 	sysfs_link_sibling(sd);
 
+	error = 0;
 out_unlock:
 	mutex_unlock(&sysfs_mutex);
-	mutex_unlock(&new_parent_inode->i_mutex);
+	if (new_parent_inode != old_parent_inode)
+		mutex_unlock(&new_parent_inode->i_mutex);
 	mutex_unlock(&old_parent_inode->i_mutex);
+	kfree(dup_name);
 
 out_release:
 	iput(new_parent_inode);
@@ -1118,6 +1063,16 @@ out:
 	return error;
 }
 
+int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
+{
+	return sysfs_mv_dir(kobj->sd, kobj->sd->s_parent, new_name);
+}
+
+int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
+{
+	return sysfs_mv_dir(kobj->sd, new_parent_kobj->sd, kobj->sd->s_name);
+}
+
 /* Relationship between s_mode and the DT_xxx types */
 static inline unsigned char dt_type(struct sysfs_dirent *sd)
 {
-- 
1.5.3.rc6.17.g1911

[PATCH 3/8] sysfs: Implement sysfs_delete_link and sysfs_rename_link

[Eric W. Biederman]

When removing a symlink sysfs_remove_link does not provide
enough information to figure out which tagged directory the symlink
falls in.  So I need sysfs_delete_link which is passed the target
of the symlink to delete.

Further half the time when we are removing a symlink the code is
actually renaming the symlink but not doing so explicitly because
we don't have a symlink rename method. So I have added sysfs_rename_link
as well.

Both of these functions now have enough information to find a symlink
in a tagged directory.  The only restriction is that they must be called
before the target kobject is renamed or deleted.  If they are called
later I loose track of which tag the target kobject was marked with
and can no longer find the old symlink to remove it.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/sysfs/symlink.c    |   31 +++++++++++++++++++++++++++++++
 include/linux/sysfs.h |   17 +++++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 54b2e5f..2a64645 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -105,6 +105,21 @@ int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
 }
 
 /**
+ *	sysfs_delete_link - remove symlink in object's directory.
+ *	@kobj:	object we're acting for.
+ *	@targ:	object we're pointing to.
+ *	@name:	name of the symlink to remove.
+ *
+ *	Unlike sysfs_remove_link sysfs_delete_link has enough information
+ *	to successfully delete symlinks in tagged directories.
+ */
+void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
+			const char *name)
+{
+	sysfs_hash_and_remove(targ, kobj->sd, name);
+}
+
+/**
  *	sysfs_remove_link - remove symlink in object's directory.
  *	@kobj:	object we're acting for.
  *	@name:	name of the symlink to remove.
@@ -122,6 +137,22 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
 	sysfs_hash_and_remove(kobj, parent_sd, name);
 }
 
+/**
+ *	sysfs_rename_link - rename symlink in object's directory.
+ *	@kobj:	object we're acting for.
+ *	@targ:	object we're pointing to.
+ *	@old:	previous name of the symlink.
+ *	@new:	new name of the symlink.
+ *
+ *	A helper function for the common rename symlink idiom.
+ */
+int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
+			const char *old, const char *new)
+{
+	sysfs_delete_link(kobj, targ, old);
+	return sysfs_create_link(kobj, targ, new);
+}
+
 static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
 				 struct sysfs_dirent *target_sd, char *path)
 {
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index ba68829..1204d45 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -117,6 +117,12 @@ int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
 					  const char *name);
 void sysfs_remove_link(struct kobject *kobj, const char *name);
 
+int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
+			const char *old_name, const char *new_name);
+
+void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
+			const char *name);
+
 int __must_check sysfs_create_group(struct kobject *kobj,
 				    const struct attribute_group *grp);
 int sysfs_update_group(struct kobject *kobj,
@@ -216,6 +222,17 @@ static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
 {
 }
 
+static inline int sysfs_rename_link(struct kobject *k, struct kobject *t,
+				    const char *old_name, const char *new_name)
+{
+	return 0;
+}
+
+static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
+				     const char *name)
+{
+}
+
 static inline int sysfs_create_group(struct kobject *kobj,
 				     const struct attribute_group *grp)
 {
-- 
1.5.3.rc6.17.g1911

[PATCH 5/8] sysfs: Remove sysfs_create_link_nowarn

[Eric W. Biederman]

All of the uses have been replaced by sysfs_rename_link which
is a clearer primitive to is also needed for the tagged directory
support.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/symlink.c    |   15 ---------------
 include/linux/sysfs.h |   10 ----------
 2 files changed, 0 insertions(+), 25 deletions(-)

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 2a64645..3c7a338 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -90,21 +90,6 @@ int sysfs_create_link(struct kobject *kobj, struct kobject *target,
 }
 
 /**
- *	sysfs_create_link_nowarn - create symlink between two objects.
- *	@kobj:	object whose directory we're creating the link in.
- *	@target:	object we're pointing to.
- *	@name:		name of the symlink.
- *
- *	This function does the same as sysf_create_link(), but it
- *	doesn't warn if the link already exists.
- */
-int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
-			     const char *name)
-{
-	return sysfs_do_create_link(kobj, target, name, 0);
-}
-
-/**
  *	sysfs_delete_link - remove symlink in object's directory.
  *	@kobj:	object we're acting for.
  *	@targ:	object we're pointing to.
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 1204d45..4e1bfdb 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -112,9 +112,6 @@ void sysfs_remove_bin_file(struct kobject *kobj, struct bin_attribute *attr);
 
 int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
 				   const char *name);
-int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
-					  struct kobject *target,
-					  const char *name);
 void sysfs_remove_link(struct kobject *kobj, const char *name);
 
 int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
@@ -211,13 +208,6 @@ static inline int sysfs_create_link(struct kobject *kobj,
 	return 0;
 }
 
-static inline int sysfs_create_link_nowarn(struct kobject *kobj,
-					   struct kobject *target,
-					   const char *name)
-{
-	return 0;
-}
-
 static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
 {
 }
-- 
1.5.3.rc6.17.g1911

Re: [PATCH 0/8] sysfs namespace support

[David Miller]

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Wed, 20 Aug 2008 23:31:00 -0700

> 
> Greg the first 4 patches are the rest of the infrastructure.
> Everything rebased quite nicely.  All of the conflicts appear
> to have been false positives.
> 
> With the addition of sysfs_rename_link sysfs_create_link_nowarn
> is never called so we can remove it.
> 
> I'm not really certain whose tree the last netns or the user
> namespace changes should live in, but I am continuing to
> have those patches in this patchset for completeness.

You can send it all through Greg or whoever, don't feel obligated to
push it through me since it depends upon the earlier bits in this
series.

[PATCH 4/8] driver core: Implement tagged directory support for device classes.

[Eric W. Biederman]

This patch enables tagging on every class directory if struct class
has a tag_type.

In addition device_del and device_rename were modified to use
sysfs_delete_link and sysfs_rename_link respectively to ensure
when these operations happen on devices whose classes have
tag_ops that they work properly.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
---
 drivers/base/class.c   |   30 ++++++++++++++++++++++---
 drivers/base/core.c    |   56 ++++++++++++++++++++++++++++++------------------
 include/linux/device.h |    3 ++
 3 files changed, 64 insertions(+), 25 deletions(-)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index cc5e28c..0cd5704 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -135,6 +135,17 @@ static void remove_class_attrs(struct class *cls)
 	}
 }
 
+static int class_setup_tagging(struct class *cls)
+{
+	enum sysfs_tag_type type;
+
+	type = cls->tag_type;
+	if (type == SYSFS_TAG_TYPE_NONE)
+		return 0;
+
+	return sysfs_make_tagged_dir(&cls->p->class_subsys.kobj, type);
+}
+
 int __class_register(struct class *cls, struct lock_class_key *key)
 {
 	struct class_private *cp;
@@ -171,13 +182,24 @@ int __class_register(struct class *cls, struct lock_class_key *key)
 	cls->p = cp;
 
 	error = kset_register(&cp->class_subsys);
-	if (error) {
-		kfree(cp);
-		return error;
-	}
+	if (error)
+		goto out_free_cp;
+
+	error = class_setup_tagging(cls);
+	if (error)
+		goto out_unregister;
+
 	error = add_class_attrs(class_get(cls));
 	class_put(cls);
+	if (error)
+		goto out_unregister;
+out:
 	return error;
+out_unregister:
+	kset_unregister(&cp->class_subsys);
+out_free_cp:
+	kfree(cp);
+	goto out;
 }
 EXPORT_SYMBOL_GPL(__class_register);
 
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 2bf7116..4fb9b00 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -122,9 +122,21 @@ static void device_release(struct kobject *kobj)
 			dev->bus_id);
 }
 
+static const void *device_sysfs_tag(struct kobject *kobj)
+{
+	struct device *dev = to_dev(kobj);
+	const void *tag = NULL;
+
+	if (dev->class && dev->class->tag_type)
+		tag = dev->class->sysfs_tag(dev);
+
+	return tag;
+}
+
 static struct kobj_type device_ktype = {
 	.release	= device_release,
 	.sysfs_ops	= &dev_sysfs_ops,
+	.sysfs_tag	= device_sysfs_tag,
 };
 
 
@@ -617,6 +629,10 @@ static struct kobject *get_device_parent(struct device *dev,
 			kobject_put(k);
 			return NULL;
 		}
+		/* If we created a new class-directory setup tagging */
+		if (dev->class->tag_type)
+			sysfs_make_tagged_dir(k, dev->class->tag_type);
+
 		/* do not emit an uevent for this simple "glue" directory */
 		return k;
 	}
@@ -707,7 +723,7 @@ out_device:
 out_busid:
 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
+		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
 				  dev->bus_id);
 #else
 	/* link in the class directory pointing to the device */
@@ -725,7 +741,7 @@ out_busid:
 	return 0;
 
 out_busid:
-	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev->bus_id);
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev->bus_id);
 #endif
 
 out_subsys:
@@ -753,13 +769,13 @@ static void device_remove_class_symlinks(struct device *dev)
 
 	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
+		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
 				  dev->bus_id);
 #else
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
 
-	sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev->bus_id);
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev->bus_id);
 #endif
 
 	sysfs_remove_link(&dev->kobj, "subsystem");
@@ -1347,6 +1363,15 @@ int device_rename(struct device *dev, char *new_name)
 	strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
 	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
 
+#ifndef CONFIG_SYSFS_DEPRECATED
+	if (dev->class) {
+		error = sysfs_rename_link(&dev->class->p->class_subsys.kobj,
+			&dev->kobj, old_device_name, new_name);
+		if (error)
+			goto out;
+	}
+#endif
+
 	error = kobject_rename(&dev->kobj, new_name);
 	if (error) {
 		strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
@@ -1355,24 +1380,13 @@ int device_rename(struct device *dev, char *new_name)
 
 #ifdef CONFIG_SYSFS_DEPRECATED
 	if (old_class_name) {
+		error = -ENOMEM;
 		new_class_name = make_class_name(dev->class->name, &dev->kobj);
-		if (new_class_name) {
-			error = sysfs_create_link_nowarn(&dev->parent->kobj,
-							 &dev->kobj,
-							 new_class_name);
-			if (error)
-				goto out;
-			sysfs_remove_link(&dev->parent->kobj, old_class_name);
-		}
-	}
-#else
-	if (dev->class) {
-		error = sysfs_create_link_nowarn(&dev->class->p->class_subsys.kobj,
-						 &dev->kobj, dev->bus_id);
-		if (error)
-			goto out;
-		sysfs_remove_link(&dev->class->p->class_subsys.kobj,
-				  old_device_name);
+		if (new_class_name)
+			error = sysfs_rename_link(&dev->parent->kobj,
+						  &dev->kobj,
+						  old_class_name,
+						  new_class_name);
 	}
 #endif
 
diff --git a/include/linux/device.h b/include/linux/device.h
index d6fdd60..8d65016 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -195,6 +195,9 @@ struct class {
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
 
+	enum sysfs_tag_type tag_type;
+	const void *(*sysfs_tag)(struct device *dev);
+
 	struct pm_ops *pm;
 	struct class_private *p;
 };
-- 
1.5.3.rc6.17.g1911

[PATCH 6/8] Revert "netns: Fix device renaming for sysfs"

[Eric W. Biederman]

This reverts commit aaf8cdc34ddba08122f02217d9d684e2f9f5d575.

Drivers like the ipw2100 call device_create_group when they
are initialized and device_remove_group when they are shutdown.
Moving them between namespaces deletes their sysfs groups early.

In particular the following call chain results.
netdev_unregister_kobject -> device_del -> kobject_del -> sysfs_remove_dir
With sysfs_remove_dir recursively deleting all of it's subdirectories,
and nothing adding them back.

Ouch!

Therefore we need to call something that ultimate calls sysfs_mv_dir
as that sysfs function can move sysfs directories between namespaces
without deleting their subdirectories or their contents.   Allowing
us to avoid placing extra boiler plate into every driver that does
something interesting with sysfs.

Currently the function that provides that capability is device_rename.
That is the code works without nasty side effects as originally written.

So remove the misguided fix for moving devices between namespaces.  The
bug in the kobject layer that inspired it has now been recognized and
fixed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 net/core/dev.c       |    4 +---
 net/core/net-sysfs.c |    7 +------
 net/core/net-sysfs.h |    1 -
 3 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 600bb23..a7e236c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3989,7 +3989,6 @@ int register_netdevice(struct net_device *dev)
 	if (dev->features & NETIF_F_SG)
 		dev->features |= NETIF_F_GSO;
 
-	netdev_initialize_kobject(dev);
 	ret = netdev_register_kobject(dev);
 	if (ret)
 		goto err_uninit;
@@ -4451,8 +4450,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	}
 
 	/* Fixup kobjects */
-	netdev_unregister_kobject(dev);
-	err = netdev_register_kobject(dev);
+	err = device_rename(&dev->dev, dev->name);
 	WARN_ON(err);
 
 	/* Add the device back in the hashes */
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c1f4e0d..c9968f1 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -449,6 +449,7 @@ int netdev_register_kobject(struct net_device *net)
 	struct device *dev = &(net->dev);
 	struct attribute_group **groups = net->sysfs_groups;
 
+	device_initialize(dev);
 	dev->class = &net_class;
 	dev->platform_data = net;
 	dev->groups = groups;
@@ -481,12 +482,6 @@ void netdev_class_remove_file(struct class_attribute *class_attr)
 EXPORT_SYMBOL(netdev_class_create_file);
 EXPORT_SYMBOL(netdev_class_remove_file);
 
-void netdev_initialize_kobject(struct net_device *net)
-{
-	struct device *device = &(net->dev);
-	device_initialize(device);
-}
-
 int netdev_kobject_init(void)
 {
 	return class_register(&net_class);
diff --git a/net/core/net-sysfs.h b/net/core/net-sysfs.h
index 14e7524..805555e 100644
--- a/net/core/net-sysfs.h
+++ b/net/core/net-sysfs.h
@@ -4,5 +4,4 @@
 int netdev_kobject_init(void);
 int netdev_register_kobject(struct net_device *);
 void netdev_unregister_kobject(struct net_device *);
-void netdev_initialize_kobject(struct net_device *);
 #endif
-- 
1.5.3.rc6.17.g1911

[PATCH 7/8] netns: Enable tagging for net_class directories in sysfs

[Eric W. Biederman]

The problem.  Network devices show up in sysfs and with the network
namespace active multiple devices with the same name can show up in
the same directory, ouch!

To avoid that problem and allow existing applications in network namespaces
to see the same interface that is currently presented in sysfs, this
patch enables the tagging directory support in sysfs.

By using the network namespace pointers as tags to separate out the
the sysfs directory entries we ensure that we don't have conflicts
in the directories and applications only see a limited set of
the network devices.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 include/linux/sysfs.h |    1 +
 net/Kconfig           |    2 +-
 net/core/net-sysfs.c  |   33 +++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 4e1bfdb..6d7eb50 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -82,6 +82,7 @@ struct sysfs_dirent;
 
 enum sysfs_tag_type {
 	SYSFS_TAG_TYPE_NONE = 0,
+	SYSFS_TAG_TYPE_NETNS,
 	SYSFS_TAG_TYPES
 };
 
diff --git a/net/Kconfig b/net/Kconfig
index 7612cc8..29e7e09 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -27,7 +27,7 @@ menu "Networking options"
 config NET_NS
 	bool "Network namespace support"
 	default n
-	depends on EXPERIMENTAL && !SYSFS && NAMESPACES
+	depends on EXPERIMENTAL && NAMESPACES
 	help
 	  Allow user space to create what appear to be multiple instances
 	  of the network stack.
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c9968f1..e4687af 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -13,7 +13,9 @@
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
+#include <linux/nsproxy.h>
 #include <net/sock.h>
+#include <net/net_namespace.h>
 #include <linux/rtnetlink.h>
 #include <linux/wireless.h>
 #include <net/iw_handler.h>
@@ -385,6 +387,24 @@ static struct attribute_group wireless_group = {
 };
 #endif
 
+static const void *net_sysfs_mount_tag(void)
+{
+	return current->nsproxy->net_ns;
+}
+
+static struct sysfs_tag_type_operations net_tag_type_operations = {
+	.mount_tag = net_sysfs_mount_tag,
+};
+
+static void net_sysfs_net_exit(struct net *net)
+{
+	sysfs_exit_tag(SYSFS_TAG_TYPE_NETNS, net);
+}
+
+static struct pernet_operations sysfs_net_ops = {
+	.exit = net_sysfs_net_exit,
+};
+
 #endif /* CONFIG_SYSFS */
 
 #ifdef CONFIG_HOTPLUG
@@ -421,6 +441,13 @@ static void netdev_release(struct device *d)
 	kfree((char *)dev - dev->padded);
 }
 
+static const void *net_sysfs_tag(struct device *d)
+{
+	struct net_device *dev;
+	dev = container_of(d, struct net_device, dev);
+	return dev_net(dev);
+}
+
 static struct class net_class = {
 	.name = "net",
 	.dev_release = netdev_release,
@@ -430,6 +457,8 @@ static struct class net_class = {
 #ifdef CONFIG_HOTPLUG
 	.dev_uevent = netdev_uevent,
 #endif
+	.tag_type = SYSFS_TAG_TYPE_NETNS,
+	.sysfs_tag = net_sysfs_tag,
 };
 
 /* Delete sysfs entries but hold kobject reference until after all
@@ -484,5 +513,9 @@ EXPORT_SYMBOL(netdev_class_remove_file);
 
 int netdev_kobject_init(void)
 {
+#ifdef CONFIG_SYSFS
+	sysfs_register_tag_type(SYSFS_TAG_TYPE_NETNS, &net_tag_type_operations);
+	register_pernet_subsys(&sysfs_net_ops);
+#endif
 	return class_register(&net_class);
 }
-- 
1.5.3.rc6.17.g1911

[PATCH 8/8] sysfs: user namespaces: fix bug with clone(CLONE_NEWUSER) with fairsched

[Eric W. Biederman]

From: Serge Hallyn <serge@us.ibm.com>

Mark the /sys/kernel/uids directory to be tagged so that processes in
different user namespaces can remount /sys and see their own uid
listings.

Without this patch, having CONFIG_FAIR_SCHED=y makes user namespaces
unusable, because when you
  clone(CLONE_NEWUSER)
it will auto-create the root userid and try to create
/sys/kernel/uids/0.  Since that already exists from the parent user
namespace, the create fails, and the clone misleadingly ends up
returning -ENOMEM.

This patch fixes the issue by allowing each user namespace to remount
/sys, and having /sys filter the /sys/kernel/uid/ entries by user
namespace.

Changelong:
v2 - Reworked for the updated sysfs api

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 include/linux/sched.h   |    1 +
 include/linux/sysfs.h   |    1 +
 kernel/user.c           |   22 ++++++++++++++++++++++
 kernel/user_namespace.c |    1 +
 4 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5850bfb..b0fe15a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -600,6 +600,7 @@ struct user_struct {
 	/* Hash table maintenance information */
 	struct hlist_node uidhash_node;
 	uid_t uid;
+	struct user_namespace *user_ns;
 
 #ifdef CONFIG_USER_SCHED
 	struct task_group *tg;
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 6d7eb50..ac88374 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -83,6 +83,7 @@ struct sysfs_dirent;
 enum sysfs_tag_type {
 	SYSFS_TAG_TYPE_NONE = 0,
 	SYSFS_TAG_TYPE_NETNS,
+	SYSFS_TAG_TYPE_USERNS,
 	SYSFS_TAG_TYPES
 };
 
diff --git a/kernel/user.c b/kernel/user.c
index 865ecf5..ca29fbc 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -53,6 +53,7 @@ struct user_struct root_user = {
 	.files		= ATOMIC_INIT(0),
 	.sigpending	= ATOMIC_INIT(0),
 	.locked_shm     = 0,
+	.user_ns	= &init_user_ns,
 #ifdef CONFIG_USER_SCHED
 	.tg		= &init_task_group,
 #endif
@@ -230,16 +231,33 @@ static struct attribute *uids_attributes[] = {
 	NULL
 };
 
+static const void *uids_mount_tag(void)
+{
+	return current->nsproxy->user_ns;
+}
+
+static struct sysfs_tag_type_operations uids_tag_type_operations = {
+	.mount_tag = uids_mount_tag,
+};
+
 /* the lifetime of user_struct is not managed by the core (now) */
 static void uids_release(struct kobject *kobj)
 {
 	return;
 }
 
+static const void *uids_sysfs_tag(struct kobject *kobj)
+{
+	struct user_struct *up;
+	up = container_of(kobj, struct user_struct, kobj);
+	return up->user_ns;
+}
+
 static struct kobj_type uids_ktype = {
 	.sysfs_ops = &kobj_sysfs_ops,
 	.default_attrs = uids_attributes,
 	.release = uids_release,
+	.sysfs_tag = uids_sysfs_tag,
 };
 
 /* create /sys/kernel/uids/<uid>/cpu_share file for this user */
@@ -272,6 +290,9 @@ int __init uids_sysfs_init(void)
 	if (!uids_kset)
 		return -ENOMEM;
 
+	sysfs_register_tag_type(SYSFS_TAG_TYPE_USERNS, &uids_tag_type_operations);
+	sysfs_make_tagged_dir(&uids_kset->kobj, SYSFS_TAG_TYPE_USERNS);
+
 	return uids_user_create(&root_user);
 }
 
@@ -405,6 +426,7 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
 
 		new->uid = uid;
 		atomic_set(&new->__count, 1);
+		new->user_ns = ns;
 
 		if (sched_create_user(new) < 0)
 			goto out_free_user;
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a9ab059..f67bbe0 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -71,6 +71,7 @@ void free_user_ns(struct kref *kref)
 	struct user_namespace *ns;
 
 	ns = container_of(kref, struct user_namespace, kref);
+	sysfs_exit_tag(SYSFS_TAG_TYPE_USERNS, ns);
 	release_uids(ns);
 	kfree(ns);
 }
-- 
1.5.3.rc6.17.g1911

Re: [PATCH 6/8] Revert "netns: Fix device renaming for sysfs"

[David Miller]

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Wed, 20 Aug 2008 23:38:31 -0700

> 
> This reverts commit aaf8cdc34ddba08122f02217d9d684e2f9f5d575.
> 
> Drivers like the ipw2100 call device_create_group when they
> are initialized and device_remove_group when they are shutdown.
> Moving them between namespaces deletes their sysfs groups early.
> 
> In particular the following call chain results.
> netdev_unregister_kobject -> device_del -> kobject_del -> sysfs_remove_dir
> With sysfs_remove_dir recursively deleting all of it's subdirectories,
> and nothing adding them back.
> 
> Ouch!
> 
> Therefore we need to call something that ultimate calls sysfs_mv_dir
> as that sysfs function can move sysfs directories between namespaces
> without deleting their subdirectories or their contents.   Allowing
> us to avoid placing extra boiler plate into every driver that does
> something interesting with sysfs.
> 
> Currently the function that provides that capability is device_rename.
> That is the code works without nasty side effects as originally written.
> 
> So remove the misguided fix for moving devices between namespaces.  The
> bug in the kobject layer that inspired it has now been recognized and
> fixed.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Acked-by: David S. Miller <davem@davemloft.net>

Re: [PATCH 7/8] netns: Enable tagging for net_class directories in sysfs

[David Miller]

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Wed, 20 Aug 2008 23:39:13 -0700

> 
> The problem.  Network devices show up in sysfs and with the network
> namespace active multiple devices with the same name can show up in
> the same directory, ouch!
> 
> To avoid that problem and allow existing applications in network namespaces
> to see the same interface that is currently presented in sysfs, this
> patch enables the tagging directory support in sysfs.
> 
> By using the network namespace pointers as tags to separate out the
> the sysfs directory entries we ensure that we don't have conflicts
> in the directories and applications only see a limited set of
> the network devices.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Acked-by: David S. Miller <davem@davemloft.net>

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Benjamin Thery]

Eric W. Biederman wrote:
> The problem.  When implementing a network namespace I need to be able
> to have multiple network devices with the same name.  Currently this
> is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
> potentially a few other directories of the form /sys/ ... /net/*.
> 
> What this patch does is to add an additional tag field to the
> sysfs dirent structure.  For directories that should show different
> contents depending on the context such as /sys/class/net/, and
> /sys/devices/virtual/net/ this tag field is used to specify the
> context in which those directories should be visible.  Effectively
> this is the same as creating multiple distinct directories with
> the same name but internally to sysfs the result is nicer.
> 
> I am calling the concept of a single directory that looks like multiple
> directories all at the same path in the filesystem tagged directories.
> 
> For the networking namespace the set of directories whose contents I need
> to filter with tags can depend on the presence or absence of hotplug
> hardware or which modules are currently loaded.  Which means I need
> a simple race free way to setup those directories as tagged.
> 
> To achieve a reace free design all tagged directories are created
> and managed by sysfs itself.
> 
> Users of this interface:
> - define a type in the sysfs_tag_type enumeration.
> - call sysfs_register_tag_types with the type and it's operations
> - call sysfs_make_tagged_dir with the tag type on directories
>   to be managed by this tag type
> - sysfs_exit_tag when an individual tag is no longer valid
> 
> - Implement mount_tag() which returns the tag of the calling process
>   so we can attach it to a sysfs superblock.
> - Implement ktype.sysfs_tag() which returns the tag of a syfs kobject.
> 
> Everything else is left up to sysfs and the driver layer.
> 
> For the network namespace mount_tag and sysfs_tag are essentially
> one line functions, and look to remain that.
> 
> Tags are currently represented a const void * pointers as that is
> both generic, prevides enough information for equality comparisons,
> and is trivial to create for current users, as it is just the
> existing namespace pointer.
> 
> The work needed in sysfs is more extensive.  At each directory
> or symlink creating I need to check if the directory it is being
> created in is a tagged directory and if so generate the appropriate
> tag to place on the sysfs_dirent.  Likewise at each symlink or
> directory removal I need to check if the sysfs directory it is
> being removed from is a tagged directory and if so figure out
> which tag goes along with the name I am deleting.
> 
> Currently only directories which hold kobjects, and
> symlinks are supported.  There is not enough information
> in the current file attribute interfaces to give us anything
> to discriminate on which makes it useless, and there are
> no potential users which makes it an uninteresting problem
> to solve.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
> ---
>  fs/sysfs/bin.c          |    2 +-
>  fs/sysfs/dir.c          |  139 ++++++++++++++++++++++++++++++++++++++++++-----
>  fs/sysfs/file.c         |   11 +++--
>  fs/sysfs/group.c        |    4 +-
>  fs/sysfs/inode.c        |    7 ++-
>  fs/sysfs/mount.c        |  115 +++++++++++++++++++++++++++++++++++++--
>  fs/sysfs/symlink.c      |    2 +-
>  fs/sysfs/sysfs.h        |   19 ++++++-
>  include/linux/kobject.h |    1 +
>  include/linux/sysfs.h   |   31 +++++++++++
>  10 files changed, 298 insertions(+), 33 deletions(-)
> 
> diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
> index 006fc64..86e1128 100644
> --- a/fs/sysfs/bin.c
> +++ b/fs/sysfs/bin.c
> @@ -252,7 +252,7 @@ int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr)
>  
>  void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr)
>  {
> -	sysfs_hash_and_remove(kobj->sd, attr->attr.name);
> +	sysfs_hash_and_remove(kobj, kobj->sd, attr->attr.name);
>  }
>  
>  EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
> diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
> index 4ffcfd2..dec7586 100644
> --- a/fs/sysfs/dir.c
> +++ b/fs/sysfs/dir.c
> @@ -30,6 +30,30 @@ DEFINE_SPINLOCK(sysfs_assoc_lock);
>  static DEFINE_SPINLOCK(sysfs_ino_lock);
>  static DEFINE_IDA(sysfs_ino_ida);
>  
> +static const void *sysfs_creation_tag(struct sysfs_dirent *parent_sd,
> +				      struct sysfs_dirent *sd)
> +{
> +	const void *tag = NULL;
> +
> +	if (sysfs_tag_type(parent_sd)) {
> +		struct kobject *kobj;
> +		switch (sysfs_type(sd)) {
> +		case SYSFS_DIR:
> +			kobj = sd->s_dir.kobj;
> +			break;
> +		case SYSFS_KOBJ_LINK:
> +			kobj = sd->s_symlink.target_sd->s_dir.kobj;
> +			break;
> +		default:
> +			BUG();
> +		}
> +		tag = kobj->ktype->sysfs_tag(kobj);
> +		/* NULL tags are reserved for internal use */
> +		BUG_ON(tag == NULL);
> +	}
> +	return tag;
> +}
> +
>  /**
>   *	sysfs_link_sibling - link sysfs_dirent into sibling list
>   *	@sd: sysfs_dirent of interest
> @@ -101,8 +125,19 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
>  struct dentry *sysfs_get_dentry(struct super_block *sb,
>  				struct sysfs_dirent *sd)
>  {
> -	struct dentry *dentry = dget(sb->s_root);
> +	struct dentry *dentry;
> +
> +	/* Bail if this sd won't show up in this superblock */
> +	if (sd->s_parent) {
> +		enum sysfs_tag_type type;
> +		const void *tag;
> +		type = sysfs_tag_type(sd->s_parent);
> +		tag = sysfs_info(sb)->tag[type];
> +		if (sd->s_tag != tag)
> +			return ERR_PTR(-EXDEV);
> +	}
>  
> +	dentry = dget(sb->s_root);
>  	while (dentry->d_fsdata != sd) {
>  		struct sysfs_dirent *cur;
>  		struct dentry *parent;
> @@ -421,10 +456,15 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
>   */
>  int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
>  {
> -	if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
> +	const void *tag = NULL;
> +
> +	tag = sysfs_creation_tag(acxt->parent_sd, sd);
> +
> +	if (sysfs_find_dirent(acxt->parent_sd, tag, sd->s_name))
>  		return -EEXIST;
>  
>  	sd->s_parent = sysfs_get(acxt->parent_sd);
> +	sd->s_tag = tag;
>  
>  	if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
>  		inc_nlink(acxt->parent_inode);
> @@ -602,13 +642,17 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
>   *	Pointer to sysfs_dirent if found, NULL if not.
>   */
>  struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
> +				       const void *tag,
>  				       const unsigned char *name)
>  {
>  	struct sysfs_dirent *sd;
>  
> -	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
> +	for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
> +		if (sd->s_tag != tag)
> +			continue;
>  		if (!strcmp(sd->s_name, name))
>  			return sd;
> +	}
>  	return NULL;
>  }
>  
> @@ -632,7 +676,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
>  	struct sysfs_dirent *sd;
>  
>  	mutex_lock(&sysfs_mutex);
> -	sd = sysfs_find_dirent(parent_sd, name);
> +	sd = sysfs_find_dirent(parent_sd, NULL, name);
>  	sysfs_get(sd);
>  	mutex_unlock(&sysfs_mutex);
>  
> @@ -699,13 +743,18 @@ static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
>  				struct nameidata *nd)
>  {
>  	struct dentry *ret = NULL;
> -	struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
> +	struct dentry *parent = dentry->d_parent;
> +	struct sysfs_dirent *parent_sd = parent->d_fsdata;
>  	struct sysfs_dirent *sd;
>  	struct inode *inode;
> +	enum sysfs_tag_type type;
> +	const void *tag;
>  
>  	mutex_lock(&sysfs_mutex);
>  
> -	sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
> +	type = sysfs_tag_type(parent_sd);
> +	tag = sysfs_info(parent->d_sb)->tag[type];
> +	sd = sysfs_find_dirent(parent_sd, tag, dentry->d_name.name);
>  
>  	/* no such entry */
>  	if (!sd) {
> @@ -913,19 +962,24 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  	struct sysfs_rename_struct *srs;
>  	struct inode *parent_inode = NULL;
>  	const char *dup_name = NULL;
> +	const void *old_tag, *tag;
>  	int error;
>  
>  	INIT_LIST_HEAD(&todo);
>  	mutex_lock(&sysfs_rename_mutex);
> +	old_tag = sd->s_tag;
> +	tag = sysfs_creation_tag(sd->s_parent, sd);
>  
>  	error = 0;
> -	if (strcmp(sd->s_name, new_name) == 0)
> +	if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
>  		goto out;	/* nothing to rename */
>  
>  	sysfs_grab_supers();
> -	error = prep_rename(&todo, sd, sd->s_parent, new_name);
> -	if (error)
> -		goto out_release;
> +	if (old_tag == tag) {
> +		error = prep_rename(&todo, sd, sd->s_parent, new_name);
> +		if (error)
> +			goto out_release;
> +	}
>  
>  	error = -ENOMEM;
>  	mutex_lock(&sysfs_mutex);
> @@ -938,7 +992,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  	mutex_lock(&sysfs_mutex);
>  
>  	error = -EEXIST;
> -	if (sysfs_find_dirent(sd->s_parent, new_name))
> +	if (sysfs_find_dirent(sd->s_parent, tag, new_name))
>  		goto out_unlock;
>  
>  	/* rename sysfs_dirent */
> @@ -949,6 +1003,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  
>  	dup_name = sd->s_name;
>  	sd->s_name = new_name;
> +	sd->s_tag = tag;
>  
>  	/* rename */
>  	list_for_each_entry(srs, &todo, list) {
> @@ -956,6 +1011,20 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  		d_move(srs->old_dentry, srs->new_dentry);
>  	}
>  
> +	/* If we are moving across superblocks drop the dcache entries */
> +	if (old_tag != tag) {
> +		struct super_block *sb;
> +		struct dentry *dentry;
> +		list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
> +			dentry = __sysfs_get_dentry(sb, sd);
> +			if (!dentry)
> +				continue;
> +			shrink_dcache_parent(dentry);
> +			d_drop(dentry);
> +			dput(dentry);
> +		}
> +	}
> +
>  	error = 0;
>  out_unlock:
>  	mutex_unlock(&sysfs_mutex);
> @@ -978,11 +1047,13 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
>  	struct sysfs_rename_struct *srs;
>  	struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
>  	int error;
> +	const void *tag;
>  
>  	INIT_LIST_HEAD(&todo);
>  	mutex_lock(&sysfs_rename_mutex);
>  	BUG_ON(!sd->s_parent);
>  	new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
> +	tag = sd->s_tag;
>  
>  	error = 0;
>  	if (sd->s_parent == new_parent_sd)
> @@ -1016,7 +1087,7 @@ again:
>  	mutex_lock(&sysfs_mutex);
>  
>  	error = -EEXIST;
> -	if (sysfs_find_dirent(new_parent_sd, sd->s_name))
> +	if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
>  		goto out_unlock;
>  
>  	error = 0;
> @@ -1055,10 +1126,12 @@ static inline unsigned char dt_type(struct sysfs_dirent *sd)
>  
>  static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
>  {
> -	struct dentry *dentry = filp->f_path.dentry;
> -	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
> +	struct dentry *parent = filp->f_path.dentry;
> +	struct sysfs_dirent *parent_sd = parent->d_fsdata;
>  	struct sysfs_dirent *pos;
>  	ino_t ino;
> +	enum sysfs_tag_type type;
> +	const void *tag;
>  
>  	if (filp->f_pos == 0) {
>  		ino = parent_sd->s_ino;
> @@ -1076,6 +1149,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
>  	if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
>  		mutex_lock(&sysfs_mutex);
>  
> +		type = sysfs_tag_type(parent_sd);
> +		tag = sysfs_info(parent->d_sb)->tag[type];
> +
>  		/* Skip the dentries we have already reported */
>  		pos = parent_sd->s_dir.children;
>  		while (pos && (filp->f_pos > pos->s_ino))
> @@ -1085,6 +1161,9 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
>  			const char * name;
>  			int len;
>  
> +			if (pos->s_tag != tag)
> +				continue;
> +
>  			name = pos->s_name;
>  			len = strlen(name);
>  			filp->f_pos = ino = pos->s_ino;
> @@ -1105,3 +1184,35 @@ const struct file_operations sysfs_dir_operations = {
>  	.read		= generic_read_dir,
>  	.readdir	= sysfs_readdir,
>  };
> +
> +/**
> + *	sysfs_make_tagged_dir - Require tags of all the entries in a directory.
> + *	@kobj:	object whose children should be filtered by tags
> + *
> + *	Once tagging has been enabled on a directory the contents
> + *	of the directory become dependent upon context captured when
> + *	sysfs was mounted.
> + */
> +int sysfs_make_tagged_dir(struct kobject *kobj, enum sysfs_tag_type type)
> +{
> +	struct sysfs_dirent *sd;
> +	int err;
> +
> +	err = -ENOENT;
> +	sd = kobj->sd;
> +
> +	mutex_lock(&sysfs_mutex);
> +	err = -EINVAL;
> +	/* We can only enable tagging when we have a valid tag type
> +	 * on empty directories where taggint has not already been
> +	 * enabled.
> +	 */
> +	if ((type > SYSFS_TAG_TYPE_NONE) && (type < SYSFS_TAG_TYPES) &&
> +	    tag_ops[type] && !sysfs_tag_type(sd) &&
> +	    (sysfs_type(sd) == SYSFS_DIR) && !sd->s_dir.children) {
> +		err = 0;
> +		sd->s_flags |= (type << SYSFS_TAG_TYPE_SHIFT);
> +	}
> +	mutex_unlock(&sysfs_mutex);
> +	return err;
> +}
> diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
> index 61c3476..091c0de 100644
> --- a/fs/sysfs/file.c
> +++ b/fs/sysfs/file.c
> @@ -476,9 +476,12 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
>  	mutex_lock(&sysfs_mutex);
>  
>  	if (sd && dir)
> -		sd = sysfs_find_dirent(sd, dir);
> +		/* Only directories are tagged, so no need to pass
> +		 * a tag explicitly.
> +		 */
> +		sd = sysfs_find_dirent(sd, NULL, dir);
>  	if (sd && attr)
> -		sd = sysfs_find_dirent(sd, attr);
> +		sd = sysfs_find_dirent(sd, NULL, attr);
>  	if (sd)
>  		sysfs_notify_dirent(sd);
>  
> @@ -640,7 +643,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file);
>  
>  void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr)
>  {
> -	sysfs_hash_and_remove(kobj->sd, attr->name);
> +	sysfs_hash_and_remove(kobj, kobj->sd, attr->name);
>  }
>  
>  
> @@ -660,7 +663,7 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
>  	else
>  		dir_sd = sysfs_get(kobj->sd);
>  	if (dir_sd) {
> -		sysfs_hash_and_remove(dir_sd, attr->name);
> +		sysfs_hash_and_remove(kobj, dir_sd, attr->name);
>  		sysfs_put(dir_sd);
>  	}
>  }
> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
> index fe61194..5fba6f2 100644
> --- a/fs/sysfs/group.c
> +++ b/fs/sysfs/group.c
> @@ -23,7 +23,7 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
>  	int i;
>  
>  	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
> -		sysfs_hash_and_remove(dir_sd, (*attr)->name);
> +		sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
>  }
>  
>  static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
> @@ -39,7 +39,7 @@ static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
>  		 * visibility.  Do this by first removing then
>  		 * re-adding (if required) the file */
>  		if (update)
> -			sysfs_hash_and_remove(dir_sd, (*attr)->name);
> +			sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
>  		if (grp->is_visible) {
>  			mode = grp->is_visible(kobj, *attr, i);
>  			if (!mode)
> diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
> index 80f8fd4..b5fc78a 100644
> --- a/fs/sysfs/inode.c
> +++ b/fs/sysfs/inode.c
> @@ -226,17 +226,20 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
>  	return inode;
>  }
>  
> -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
> +			  const char *name)
>  {
>  	struct sysfs_addrm_cxt acxt;
>  	struct sysfs_dirent *sd;
> +	const void *tag;
>  
>  	if (!dir_sd)
>  		return -ENOENT;
>  
>  	sysfs_addrm_start(&acxt, dir_sd);
> +	tag = kobj->sd->s_tag;
>  
> -	sd = sysfs_find_dirent(dir_sd, name);
> +	sd = sysfs_find_dirent(dir_sd, tag, name);
>  	if (sd)
>  		sysfs_remove_one(&acxt, sd);
>  
> diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
> index 6ebda1a..8f2237a 100644
> --- a/fs/sysfs/mount.c
> +++ b/fs/sysfs/mount.c
> @@ -35,12 +35,15 @@ static const struct super_operations sysfs_ops = {
>  struct sysfs_dirent sysfs_root = {
>  	.s_name		= "",
>  	.s_count	= ATOMIC_INIT(1),
> -	.s_flags	= SYSFS_DIR,
> +	.s_flags	= SYSFS_DIR | (SYSFS_TAG_TYPE_NONE << SYSFS_TAG_TYPE_SHIFT),
>  	.s_mode		= S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
>  	.s_ino		= 1,
>  };
>  
> -static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
> +struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
> +
> +static int sysfs_fill_super(struct super_block *sb, void *data, int silent,
> +	const void *tags[SYSFS_TAG_TYPES])
>  {
>  	struct sysfs_super_info *info = NULL;
>  	struct inode *inode = NULL;
> @@ -76,8 +79,10 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
>  		goto out_err;
>  	}
>  	root->d_fsdata = &sysfs_root;
> +	root->d_sb = sb;
>  	sb->s_root = root;
>  	sb->s_fs_info = info;
> +	memcpy(info->tag, tags, sizeof(info->tag[0])*SYSFS_TAG_TYPES);
>  	return 0;
>  
>  out_err:
> @@ -89,20 +94,74 @@ out_err:
>  	return error;
>  }
>  
> +static int sysfs_test_super(struct super_block *sb, void *ptr)
> +{
> +	const void **tag = ptr;
> +	struct sysfs_super_info *info = sysfs_info(sb);
> +	enum sysfs_tag_type type;
> +	int found = 1;
> +
> +	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
> +		if (info->tag[type] != tag[type]) {
> +			found = 0;
> +			break;
> +		}
> +	}
> +
> +	return found;
> +}
> +
>  static int sysfs_get_sb(struct file_system_type *fs_type,
>  	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
>  {
> -	int rc;
> +	const void *tag[SYSFS_TAG_TYPES];
> +	struct super_block *sb;
> +	int error;
> +	enum sysfs_tag_type type;
> +
> +	for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
> +		tag[type] = NULL;
> +		if (!tag_ops[type])
> +			continue;
> +		tag[type] = tag_ops[type]->mount_tag();
> +	}
> +
>  	mutex_lock(&sysfs_rename_mutex);
> -	rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
> +	sb = sget(fs_type, sysfs_test_super, set_anon_super, tag);
> +	if (IS_ERR(sb)) {
> +		error = PTR_ERR(sb);
> +		goto out;
> +	}
> +	if (!sb->s_root) {
> +		sb->s_flags = flags;
> +		error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0,
> +					tag);
> +		if (error) {
> +			up_write(&sb->s_umount);
> +			deactivate_super(sb);
> +			goto out;
> +		}
> +		sb->s_flags |= MS_ACTIVE;
> +	}
> +	do_remount_sb(sb, flags, data, 0);
> +	error = simple_set_mnt(mnt, sb);
> +out:
>  	mutex_unlock(&sysfs_rename_mutex);
> -	return rc;
> +	return error;
> +}
> +
> +static void sysfs_kill_sb(struct super_block *sb)
> +{
> +	struct sysfs_super_info *info = sysfs_info(sb);
> +
> +	kill_anon_super(sb);
> +	kfree(info);
>  }
>  
>  struct file_system_type sysfs_fs_type = {
>  	.name		= "sysfs",
>  	.get_sb		= sysfs_get_sb,
> -	.kill_sb	= kill_anon_super,
> +	.kill_sb	= sysfs_kill_sb,
>  };
>  
>  void sysfs_grab_supers(void)
> @@ -146,6 +205,50 @@ restart:
>  	spin_unlock(&sb_lock);
>  }
>  
> +int sysfs_register_tag_type(enum sysfs_tag_type type, struct sysfs_tag_type_operations *ops)
> +{
> +	int error;
> +
> +	mutex_lock(&sysfs_rename_mutex);
> +
> +	error = -EINVAL;
> +	if (type >= SYSFS_TAG_TYPES)
> +		goto out;
> +
> +	error = -EINVAL;
> +	if (type <= SYSFS_TAG_TYPE_NONE)
> +		goto out;
> +
> +	error = -EBUSY;
> +	if (tag_ops[type])
> +		goto out;
> +
> +	error = 0;
> +	tag_ops[type] = ops;
> +
> +out:
> +	mutex_unlock(&sysfs_rename_mutex);
> +	return error;
> +}
> +
> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
> +{
> +	/* Allow the tag to go away while sysfs is still mounted. */
> +	struct super_block *sb;
> +	mutex_lock(&sysfs_rename_mutex);
> +	sysfs_grab_supers();
> +	mutex_lock(&sysfs_mutex);
> +	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
> +		struct sysfs_super_info *info = sysfs_info(sb);
> +		if (info->tag[type] != tag)
> +			continue;
> +		info->tag[type] = NULL;
> +	}
> +	mutex_unlock(&sysfs_mutex);
> +	sysfs_release_supers();
> +	mutex_unlock(&sysfs_rename_mutex);
> +}
> +
>  int __init sysfs_init(void)
>  {
>  	int err = -ENOMEM;
> diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
> index a3ba217..54b2e5f 100644
> --- a/fs/sysfs/symlink.c
> +++ b/fs/sysfs/symlink.c
> @@ -119,7 +119,7 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
>  	else
>  		parent_sd = kobj->sd;
>  
> -	sysfs_hash_and_remove(parent_sd, name);
> +	sysfs_hash_and_remove(kobj, parent_sd, name);
>  }
>  
>  static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
> diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
> index f0e5ecb..67115ec 100644
> --- a/fs/sysfs/sysfs.h
> +++ b/fs/sysfs/sysfs.h
> @@ -45,6 +45,7 @@ struct sysfs_dirent {
>  	struct sysfs_dirent	*s_sibling;
>  	const char		*s_name;
>  
> +	const void		*s_tag;
>  	union {
>  		struct sysfs_elem_dir		s_dir;
>  		struct sysfs_elem_symlink	s_symlink;
> @@ -67,14 +68,22 @@ struct sysfs_dirent {
>  #define SYSFS_KOBJ_LINK			0x0008
>  #define SYSFS_COPY_NAME			(SYSFS_DIR | SYSFS_KOBJ_LINK)
>  
> -#define SYSFS_FLAG_MASK			~SYSFS_TYPE_MASK
> -#define SYSFS_FLAG_REMOVED		0x0200
> +#define SYSFS_TAG_TYPE_MASK		0xff00
> +#define SYSFS_TAG_TYPE_SHIFT		8
> +
> +#define SYSFS_FLAG_MASK			~(SYSFS_TYPE_MASK | SYSFS_TAG_TYPE_MASK)
> +#define SYSFS_FLAG_REMOVED		0x020000
>  
>  static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
>  {
>  	return sd->s_flags & SYSFS_TYPE_MASK;
>  }
>  
> +static inline enum sysfs_tag_type sysfs_tag_type(struct sysfs_dirent *sd)
> +{
> +	return (sd->s_flags & SYSFS_TAG_TYPE_MASK) >> SYSFS_TAG_TYPE_SHIFT;
> +}
> +
>  /*
>   * Context structure to be used while adding/removing nodes.
>   */
> @@ -87,6 +96,7 @@ struct sysfs_addrm_cxt {
>  
>  struct sysfs_super_info {
>  	int	grabbed;
> +	const void *tag[SYSFS_TAG_TYPES];
>  };
>  
>  #define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
> @@ -98,6 +108,7 @@ extern struct sysfs_dirent sysfs_root;
>  extern struct super_block *sysfs_sb;
>  extern struct kmem_cache *sysfs_dir_cachep;
>  extern struct file_system_type sysfs_fs_type;
> +extern struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
>  
>  void sysfs_grab_supers(void);
>  void sysfs_release_supers(void);
> @@ -124,6 +135,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd);
>  void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
>  
>  struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
> +				       const void *tag,
>  				       const unsigned char *name);
>  struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
>  				      const unsigned char *name);
> @@ -158,7 +170,8 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
>  struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
>  int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct iattr *iattr);
>  int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
> -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent *dir_sd,
> +			  const char *name);
>  int sysfs_inode_init(void);
>  
>  /*
> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
> index 5437ac0..beb3573 100644
> --- a/include/linux/kobject.h
> +++ b/include/linux/kobject.h
> @@ -105,6 +105,7 @@ struct kobj_type {
>  	void (*release)(struct kobject *kobj);
>  	struct sysfs_ops *sysfs_ops;
>  	struct attribute **default_attrs;
> +	const void *(*sysfs_tag)(struct kobject *kobj);
>  };
>  
>  struct kobj_uevent_env {
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index d8e0230..ba68829 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -80,6 +80,15 @@ struct sysfs_ops {
>  
>  struct sysfs_dirent;
>  
> +enum sysfs_tag_type {
> +	SYSFS_TAG_TYPE_NONE = 0,
> +	SYSFS_TAG_TYPES
> +};
> +
> +struct sysfs_tag_type_operations {
> +	const void *(*mount_tag)(void);
> +};
> +
>  #ifdef CONFIG_SYSFS
>  
>  int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
> @@ -126,6 +135,12 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
>  struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
>  void sysfs_put(struct sysfs_dirent *sd);
>  void sysfs_printk_last_file(void);
> +
> +int sysfs_make_tagged_dir(struct kobject *, enum sysfs_tag_type tag_type);
> +int sysfs_register_tag_type(enum sysfs_tag_type type,
> +			    struct sysfs_tag_type_operations *ops);
> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag);
> +
>  int __must_check sysfs_init(void);
>  
>  #else /* CONFIG_SYSFS */
> @@ -249,6 +264,22 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
>  {
>  }
>  
> +staticn inline int sysfs_make_tagged_dir(struct kobject *kobj,
    ______^

This typo is still present in your patch in the CONFIG_SYSFS=n case.

Otherwise the patchset, combined with the patches Greg has already
merged in his tree, still works great for me with network namespaces.

--Benjamin

> +						enum sysfs_tag_type tag_type)
> +{
> +	return 0;
> +}
> +
> +static inline int sysfs_register_tag_type(enum sysfs_tag_type type,
> +					struct sysfs_tag_type_operations *ops)
> +{
> +	return 0;
> +}
> +
> +static inline void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
> +{
> +}
> +
>  static inline int __must_check sysfs_init(void)
>  {
>  	return 0;


-- 
B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D

    http://www.bull.com

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Mark Ryden]

Hello,
 I hope that this patch (from 4.7.08) was not forgetten... I don't see
it for example in linux-net (I have an up-to-date linux-next git
tree).

Regards,
Mark

On Wed, Aug 27, 2008 at 6:18 PM, Benjamin Thery <benjamin.thery@bull.net> wrote:
> Eric W. Biederman wrote:
>>
>> The problem.  When implementing a network namespace I need to be able
>> to have multiple network devices with the same name.  Currently this
>> is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
>> potentially a few other directories of the form /sys/ ... /net/*.
>>
>> What this patch does is to add an additional tag field to the
>> sysfs dirent structure.  For directories that should show different
>> contents depending on the context such as /sys/class/net/, and
>> /sys/devices/virtual/net/ this tag field is used to specify the
>> context in which those directories should be visible.  Effectively
>> this is the same as creating multiple distinct directories with
>> the same name but internally to sysfs the result is nicer.
>>
>> I am calling the concept of a single directory that looks like multiple
>> directories all at the same path in the filesystem tagged directories.
>>
>> For the networking namespace the set of directories whose contents I need
>> to filter with tags can depend on the presence or absence of hotplug
>> hardware or which modules are currently loaded.  Which means I need
>> a simple race free way to setup those directories as tagged.
>>
>> To achieve a reace free design all tagged directories are created
>> and managed by sysfs itself.
>>
>> Users of this interface:
>> - define a type in the sysfs_tag_type enumeration.
>> - call sysfs_register_tag_types with the type and it's operations
>> - call sysfs_make_tagged_dir with the tag type on directories
>>  to be managed by this tag type
>> - sysfs_exit_tag when an individual tag is no longer valid
>>
>> - Implement mount_tag() which returns the tag of the calling process
>>  so we can attach it to a sysfs superblock.
>> - Implement ktype.sysfs_tag() which returns the tag of a syfs kobject.
>>
>> Everything else is left up to sysfs and the driver layer.
>>
>> For the network namespace mount_tag and sysfs_tag are essentially
>> one line functions, and look to remain that.
>>
>> Tags are currently represented a const void * pointers as that is
>> both generic, prevides enough information for equality comparisons,
>> and is trivial to create for current users, as it is just the
>> existing namespace pointer.
>>
>> The work needed in sysfs is more extensive.  At each directory
>> or symlink creating I need to check if the directory it is being
>> created in is a tagged directory and if so generate the appropriate
>> tag to place on the sysfs_dirent.  Likewise at each symlink or
>> directory removal I need to check if the sysfs directory it is
>> being removed from is a tagged directory and if so figure out
>> which tag goes along with the name I am deleting.
>>
>> Currently only directories which hold kobjects, and
>> symlinks are supported.  There is not enough information
>> in the current file attribute interfaces to give us anything
>> to discriminate on which makes it useless, and there are
>> no potential users which makes it an uninteresting problem
>> to solve.
>>
>> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>> Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
>> ---
>>  fs/sysfs/bin.c          |    2 +-
>>  fs/sysfs/dir.c          |  139
>> ++++++++++++++++++++++++++++++++++++++++++-----
>>  fs/sysfs/file.c         |   11 +++--
>>  fs/sysfs/group.c        |    4 +-
>>  fs/sysfs/inode.c        |    7 ++-
>>  fs/sysfs/mount.c        |  115 +++++++++++++++++++++++++++++++++++++--
>>  fs/sysfs/symlink.c      |    2 +-
>>  fs/sysfs/sysfs.h        |   19 ++++++-
>>  include/linux/kobject.h |    1 +
>>  include/linux/sysfs.h   |   31 +++++++++++
>>  10 files changed, 298 insertions(+), 33 deletions(-)
>>
>> diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
>> index 006fc64..86e1128 100644
>> --- a/fs/sysfs/bin.c
>> +++ b/fs/sysfs/bin.c
>> @@ -252,7 +252,7 @@ int sysfs_create_bin_file(struct kobject * kobj,
>> struct bin_attribute * attr)
>>   void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute *
>> attr)
>>  {
>> -       sysfs_hash_and_remove(kobj->sd, attr->attr.name);
>> +       sysfs_hash_and_remove(kobj, kobj->sd, attr->attr.name);
>>  }
>>   EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
>> diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
>> index 4ffcfd2..dec7586 100644
>> --- a/fs/sysfs/dir.c
>> +++ b/fs/sysfs/dir.c
>> @@ -30,6 +30,30 @@ DEFINE_SPINLOCK(sysfs_assoc_lock);
>>  static DEFINE_SPINLOCK(sysfs_ino_lock);
>>  static DEFINE_IDA(sysfs_ino_ida);
>>  +static const void *sysfs_creation_tag(struct sysfs_dirent *parent_sd,
>> +                                     struct sysfs_dirent *sd)
>> +{
>> +       const void *tag = NULL;
>> +
>> +       if (sysfs_tag_type(parent_sd)) {
>> +               struct kobject *kobj;
>> +               switch (sysfs_type(sd)) {
>> +               case SYSFS_DIR:
>> +                       kobj = sd->s_dir.kobj;
>> +                       break;
>> +               case SYSFS_KOBJ_LINK:
>> +                       kobj = sd->s_symlink.target_sd->s_dir.kobj;
>> +                       break;
>> +               default:
>> +                       BUG();
>> +               }
>> +               tag = kobj->ktype->sysfs_tag(kobj);
>> +               /* NULL tags are reserved for internal use */
>> +               BUG_ON(tag == NULL);
>> +       }
>> +       return tag;
>> +}
>> +
>>  /**
>>  *     sysfs_link_sibling - link sysfs_dirent into sibling list
>>  *     @sd: sysfs_dirent of interest
>> @@ -101,8 +125,19 @@ static void sysfs_unlink_sibling(struct sysfs_dirent
>> *sd)
>>  struct dentry *sysfs_get_dentry(struct super_block *sb,
>>                                struct sysfs_dirent *sd)
>>  {
>> -       struct dentry *dentry = dget(sb->s_root);
>> +       struct dentry *dentry;
>> +
>> +       /* Bail if this sd won't show up in this superblock */
>> +       if (sd->s_parent) {
>> +               enum sysfs_tag_type type;
>> +               const void *tag;
>> +               type = sysfs_tag_type(sd->s_parent);
>> +               tag = sysfs_info(sb)->tag[type];
>> +               if (sd->s_tag != tag)
>> +                       return ERR_PTR(-EXDEV);
>> +       }
>>  +       dentry = dget(sb->s_root);
>>        while (dentry->d_fsdata != sd) {
>>                struct sysfs_dirent *cur;
>>                struct dentry *parent;
>> @@ -421,10 +456,15 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
>>  */
>>  int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent
>> *sd)
>>  {
>> -       if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
>> +       const void *tag = NULL;
>> +
>> +       tag = sysfs_creation_tag(acxt->parent_sd, sd);
>> +
>> +       if (sysfs_find_dirent(acxt->parent_sd, tag, sd->s_name))
>>                return -EEXIST;
>>          sd->s_parent = sysfs_get(acxt->parent_sd);
>> +       sd->s_tag = tag;
>>          if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
>>                inc_nlink(acxt->parent_inode);
>> @@ -602,13 +642,17 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt
>> *acxt)
>>  *     Pointer to sysfs_dirent if found, NULL if not.
>>  */
>>  struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
>> +                                      const void *tag,
>>                                       const unsigned char *name)
>>  {
>>        struct sysfs_dirent *sd;
>>  -       for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
>> +       for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
>> +               if (sd->s_tag != tag)
>> +                       continue;
>>                if (!strcmp(sd->s_name, name))
>>                        return sd;
>> +       }
>>        return NULL;
>>  }
>>  @@ -632,7 +676,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct
>> sysfs_dirent *parent_sd,
>>        struct sysfs_dirent *sd;
>>          mutex_lock(&sysfs_mutex);
>> -       sd = sysfs_find_dirent(parent_sd, name);
>> +       sd = sysfs_find_dirent(parent_sd, NULL, name);
>>        sysfs_get(sd);
>>        mutex_unlock(&sysfs_mutex);
>>  @@ -699,13 +743,18 @@ static struct dentry * sysfs_lookup(struct inode
>> *dir, struct dentry *dentry,
>>                                struct nameidata *nd)
>>  {
>>        struct dentry *ret = NULL;
>> -       struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
>> +       struct dentry *parent = dentry->d_parent;
>> +       struct sysfs_dirent *parent_sd = parent->d_fsdata;
>>        struct sysfs_dirent *sd;
>>        struct inode *inode;
>> +       enum sysfs_tag_type type;
>> +       const void *tag;
>>          mutex_lock(&sysfs_mutex);
>>  -       sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
>> +       type = sysfs_tag_type(parent_sd);
>> +       tag = sysfs_info(parent->d_sb)->tag[type];
>> +       sd = sysfs_find_dirent(parent_sd, tag, dentry->d_name.name);
>>          /* no such entry */
>>        if (!sd) {
>> @@ -913,19 +962,24 @@ int sysfs_rename_dir(struct kobject * kobj, const
>> char *new_name)
>>        struct sysfs_rename_struct *srs;
>>        struct inode *parent_inode = NULL;
>>        const char *dup_name = NULL;
>> +       const void *old_tag, *tag;
>>        int error;
>>          INIT_LIST_HEAD(&todo);
>>        mutex_lock(&sysfs_rename_mutex);
>> +       old_tag = sd->s_tag;
>> +       tag = sysfs_creation_tag(sd->s_parent, sd);
>>          error = 0;
>> -       if (strcmp(sd->s_name, new_name) == 0)
>> +       if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
>>                goto out;       /* nothing to rename */
>>          sysfs_grab_supers();
>> -       error = prep_rename(&todo, sd, sd->s_parent, new_name);
>> -       if (error)
>> -               goto out_release;
>> +       if (old_tag == tag) {
>> +               error = prep_rename(&todo, sd, sd->s_parent, new_name);
>> +               if (error)
>> +                       goto out_release;
>> +       }
>>          error = -ENOMEM;
>>        mutex_lock(&sysfs_mutex);
>> @@ -938,7 +992,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char
>> *new_name)
>>        mutex_lock(&sysfs_mutex);
>>          error = -EEXIST;
>> -       if (sysfs_find_dirent(sd->s_parent, new_name))
>> +       if (sysfs_find_dirent(sd->s_parent, tag, new_name))
>>                goto out_unlock;
>>          /* rename sysfs_dirent */
>> @@ -949,6 +1003,7 @@ int sysfs_rename_dir(struct kobject * kobj, const
>> char *new_name)
>>          dup_name = sd->s_name;
>>        sd->s_name = new_name;
>> +       sd->s_tag = tag;
>>          /* rename */
>>        list_for_each_entry(srs, &todo, list) {
>> @@ -956,6 +1011,20 @@ int sysfs_rename_dir(struct kobject * kobj, const
>> char *new_name)
>>                d_move(srs->old_dentry, srs->new_dentry);
>>        }
>>  +       /* If we are moving across superblocks drop the dcache entries */
>> +       if (old_tag != tag) {
>> +               struct super_block *sb;
>> +               struct dentry *dentry;
>> +               list_for_each_entry(sb, &sysfs_fs_type.fs_supers,
>> s_instances) {
>> +                       dentry = __sysfs_get_dentry(sb, sd);
>> +                       if (!dentry)
>> +                               continue;
>> +                       shrink_dcache_parent(dentry);
>> +                       d_drop(dentry);
>> +                       dput(dentry);
>> +               }
>> +       }
>> +
>>        error = 0;
>>  out_unlock:
>>        mutex_unlock(&sysfs_mutex);
>> @@ -978,11 +1047,13 @@ int sysfs_move_dir(struct kobject *kobj, struct
>> kobject *new_parent_kobj)
>>        struct sysfs_rename_struct *srs;
>>        struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
>>        int error;
>> +       const void *tag;
>>          INIT_LIST_HEAD(&todo);
>>        mutex_lock(&sysfs_rename_mutex);
>>        BUG_ON(!sd->s_parent);
>>        new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd :
>> &sysfs_root;
>> +       tag = sd->s_tag;
>>          error = 0;
>>        if (sd->s_parent == new_parent_sd)
>> @@ -1016,7 +1087,7 @@ again:
>>        mutex_lock(&sysfs_mutex);
>>          error = -EEXIST;
>> -       if (sysfs_find_dirent(new_parent_sd, sd->s_name))
>> +       if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
>>                goto out_unlock;
>>          error = 0;
>> @@ -1055,10 +1126,12 @@ static inline unsigned char dt_type(struct
>> sysfs_dirent *sd)
>>   static int sysfs_readdir(struct file * filp, void * dirent, filldir_t
>> filldir)
>>  {
>> -       struct dentry *dentry = filp->f_path.dentry;
>> -       struct sysfs_dirent * parent_sd = dentry->d_fsdata;
>> +       struct dentry *parent = filp->f_path.dentry;
>> +       struct sysfs_dirent *parent_sd = parent->d_fsdata;
>>        struct sysfs_dirent *pos;
>>        ino_t ino;
>> +       enum sysfs_tag_type type;
>> +       const void *tag;
>>          if (filp->f_pos == 0) {
>>                ino = parent_sd->s_ino;
>> @@ -1076,6 +1149,9 @@ static int sysfs_readdir(struct file * filp, void *
>> dirent, filldir_t filldir)
>>        if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
>>                mutex_lock(&sysfs_mutex);
>>  +               type = sysfs_tag_type(parent_sd);
>> +               tag = sysfs_info(parent->d_sb)->tag[type];
>> +
>>                /* Skip the dentries we have already reported */
>>                pos = parent_sd->s_dir.children;
>>                while (pos && (filp->f_pos > pos->s_ino))
>> @@ -1085,6 +1161,9 @@ static int sysfs_readdir(struct file * filp, void *
>> dirent, filldir_t filldir)
>>                        const char * name;
>>                        int len;
>>  +                       if (pos->s_tag != tag)
>> +                               continue;
>> +
>>                        name = pos->s_name;
>>                        len = strlen(name);
>>                        filp->f_pos = ino = pos->s_ino;
>> @@ -1105,3 +1184,35 @@ const struct file_operations sysfs_dir_operations =
>> {
>>        .read           = generic_read_dir,
>>        .readdir        = sysfs_readdir,
>>  };
>> +
>> +/**
>> + *     sysfs_make_tagged_dir - Require tags of all the entries in a
>> directory.
>> + *     @kobj:  object whose children should be filtered by tags
>> + *
>> + *     Once tagging has been enabled on a directory the contents
>> + *     of the directory become dependent upon context captured when
>> + *     sysfs was mounted.
>> + */
>> +int sysfs_make_tagged_dir(struct kobject *kobj, enum sysfs_tag_type type)
>> +{
>> +       struct sysfs_dirent *sd;
>> +       int err;
>> +
>> +       err = -ENOENT;
>> +       sd = kobj->sd;
>> +
>> +       mutex_lock(&sysfs_mutex);
>> +       err = -EINVAL;
>> +       /* We can only enable tagging when we have a valid tag type
>> +        * on empty directories where taggint has not already been
>> +        * enabled.
>> +        */
>> +       if ((type > SYSFS_TAG_TYPE_NONE) && (type < SYSFS_TAG_TYPES) &&
>> +           tag_ops[type] && !sysfs_tag_type(sd) &&
>> +           (sysfs_type(sd) == SYSFS_DIR) && !sd->s_dir.children) {
>> +               err = 0;
>> +               sd->s_flags |= (type << SYSFS_TAG_TYPE_SHIFT);
>> +       }
>> +       mutex_unlock(&sysfs_mutex);
>> +       return err;
>> +}
>> diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
>> index 61c3476..091c0de 100644
>> --- a/fs/sysfs/file.c
>> +++ b/fs/sysfs/file.c
>> @@ -476,9 +476,12 @@ void sysfs_notify(struct kobject *k, char *dir, char
>> *attr)
>>        mutex_lock(&sysfs_mutex);
>>          if (sd && dir)
>> -               sd = sysfs_find_dirent(sd, dir);
>> +               /* Only directories are tagged, so no need to pass
>> +                * a tag explicitly.
>> +                */
>> +               sd = sysfs_find_dirent(sd, NULL, dir);
>>        if (sd && attr)
>> -               sd = sysfs_find_dirent(sd, attr);
>> +               sd = sysfs_find_dirent(sd, NULL, attr);
>>        if (sd)
>>                sysfs_notify_dirent(sd);
>>  @@ -640,7 +643,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file);
>>   void sysfs_remove_file(struct kobject * kobj, const struct attribute *
>> attr)
>>  {
>> -       sysfs_hash_and_remove(kobj->sd, attr->name);
>> +       sysfs_hash_and_remove(kobj, kobj->sd, attr->name);
>>  }
>>   @@ -660,7 +663,7 @@ void sysfs_remove_file_from_group(struct kobject
>> *kobj,
>>        else
>>                dir_sd = sysfs_get(kobj->sd);
>>        if (dir_sd) {
>> -               sysfs_hash_and_remove(dir_sd, attr->name);
>> +               sysfs_hash_and_remove(kobj, dir_sd, attr->name);
>>                sysfs_put(dir_sd);
>>        }
>>  }
>> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
>> index fe61194..5fba6f2 100644
>> --- a/fs/sysfs/group.c
>> +++ b/fs/sysfs/group.c
>> @@ -23,7 +23,7 @@ static void remove_files(struct sysfs_dirent *dir_sd,
>> struct kobject *kobj,
>>        int i;
>>          for (i = 0, attr = grp->attrs; *attr; i++, attr++)
>> -               sysfs_hash_and_remove(dir_sd, (*attr)->name);
>> +               sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
>>  }
>>   static int create_files(struct sysfs_dirent *dir_sd, struct kobject
>> *kobj,
>> @@ -39,7 +39,7 @@ static int create_files(struct sysfs_dirent *dir_sd,
>> struct kobject *kobj,
>>                 * visibility.  Do this by first removing then
>>                 * re-adding (if required) the file */
>>                if (update)
>> -                       sysfs_hash_and_remove(dir_sd, (*attr)->name);
>> +                       sysfs_hash_and_remove(kobj, dir_sd,
>> (*attr)->name);
>>                if (grp->is_visible) {
>>                        mode = grp->is_visible(kobj, *attr, i);
>>                        if (!mode)
>> diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
>> index 80f8fd4..b5fc78a 100644
>> --- a/fs/sysfs/inode.c
>> +++ b/fs/sysfs/inode.c
>> @@ -226,17 +226,20 @@ struct inode * sysfs_get_inode(struct sysfs_dirent
>> *sd)
>>        return inode;
>>  }
>>  -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
>> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent
>> *dir_sd,
>> +                         const char *name)
>>  {
>>        struct sysfs_addrm_cxt acxt;
>>        struct sysfs_dirent *sd;
>> +       const void *tag;
>>          if (!dir_sd)
>>                return -ENOENT;
>>          sysfs_addrm_start(&acxt, dir_sd);
>> +       tag = kobj->sd->s_tag;
>>  -       sd = sysfs_find_dirent(dir_sd, name);
>> +       sd = sysfs_find_dirent(dir_sd, tag, name);
>>        if (sd)
>>                sysfs_remove_one(&acxt, sd);
>>  diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
>> index 6ebda1a..8f2237a 100644
>> --- a/fs/sysfs/mount.c
>> +++ b/fs/sysfs/mount.c
>> @@ -35,12 +35,15 @@ static const struct super_operations sysfs_ops = {
>>  struct sysfs_dirent sysfs_root = {
>>        .s_name         = "",
>>        .s_count        = ATOMIC_INIT(1),
>> -       .s_flags        = SYSFS_DIR,
>> +       .s_flags        = SYSFS_DIR | (SYSFS_TAG_TYPE_NONE <<
>> SYSFS_TAG_TYPE_SHIFT),
>>        .s_mode         = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
>>        .s_ino          = 1,
>>  };
>>  -static int sysfs_fill_super(struct super_block *sb, void *data, int
>> silent)
>> +struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
>> +
>> +static int sysfs_fill_super(struct super_block *sb, void *data, int
>> silent,
>> +       const void *tags[SYSFS_TAG_TYPES])
>>  {
>>        struct sysfs_super_info *info = NULL;
>>        struct inode *inode = NULL;
>> @@ -76,8 +79,10 @@ static int sysfs_fill_super(struct super_block *sb,
>> void *data, int silent)
>>                goto out_err;
>>        }
>>        root->d_fsdata = &sysfs_root;
>> +       root->d_sb = sb;
>>        sb->s_root = root;
>>        sb->s_fs_info = info;
>> +       memcpy(info->tag, tags, sizeof(info->tag[0])*SYSFS_TAG_TYPES);
>>        return 0;
>>   out_err:
>> @@ -89,20 +94,74 @@ out_err:
>>        return error;
>>  }
>>  +static int sysfs_test_super(struct super_block *sb, void *ptr)
>> +{
>> +       const void **tag = ptr;
>> +       struct sysfs_super_info *info = sysfs_info(sb);
>> +       enum sysfs_tag_type type;
>> +       int found = 1;
>> +
>> +       for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
>> +               if (info->tag[type] != tag[type]) {
>> +                       found = 0;
>> +                       break;
>> +               }
>> +       }
>> +
>> +       return found;
>> +}
>> +
>>  static int sysfs_get_sb(struct file_system_type *fs_type,
>>        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
>>  {
>> -       int rc;
>> +       const void *tag[SYSFS_TAG_TYPES];
>> +       struct super_block *sb;
>> +       int error;
>> +       enum sysfs_tag_type type;
>> +
>> +       for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
>> +               tag[type] = NULL;
>> +               if (!tag_ops[type])
>> +                       continue;
>> +               tag[type] = tag_ops[type]->mount_tag();
>> +       }
>> +
>>        mutex_lock(&sysfs_rename_mutex);
>> -       rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
>> +       sb = sget(fs_type, sysfs_test_super, set_anon_super, tag);
>> +       if (IS_ERR(sb)) {
>> +               error = PTR_ERR(sb);
>> +               goto out;
>> +       }
>> +       if (!sb->s_root) {
>> +               sb->s_flags = flags;
>> +               error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 :
>> 0,
>> +                                       tag);
>> +               if (error) {
>> +                       up_write(&sb->s_umount);
>> +                       deactivate_super(sb);
>> +                       goto out;
>> +               }
>> +               sb->s_flags |= MS_ACTIVE;
>> +       }
>> +       do_remount_sb(sb, flags, data, 0);
>> +       error = simple_set_mnt(mnt, sb);
>> +out:
>>        mutex_unlock(&sysfs_rename_mutex);
>> -       return rc;
>> +       return error;
>> +}
>> +
>> +static void sysfs_kill_sb(struct super_block *sb)
>> +{
>> +       struct sysfs_super_info *info = sysfs_info(sb);
>> +
>> +       kill_anon_super(sb);
>> +       kfree(info);
>>  }
>>   struct file_system_type sysfs_fs_type = {
>>        .name           = "sysfs",
>>        .get_sb         = sysfs_get_sb,
>> -       .kill_sb        = kill_anon_super,
>> +       .kill_sb        = sysfs_kill_sb,
>>  };
>>   void sysfs_grab_supers(void)
>> @@ -146,6 +205,50 @@ restart:
>>        spin_unlock(&sb_lock);
>>  }
>>  +int sysfs_register_tag_type(enum sysfs_tag_type type, struct
>> sysfs_tag_type_operations *ops)
>> +{
>> +       int error;
>> +
>> +       mutex_lock(&sysfs_rename_mutex);
>> +
>> +       error = -EINVAL;
>> +       if (type >= SYSFS_TAG_TYPES)
>> +               goto out;
>> +
>> +       error = -EINVAL;
>> +       if (type <= SYSFS_TAG_TYPE_NONE)
>> +               goto out;
>> +
>> +       error = -EBUSY;
>> +       if (tag_ops[type])
>> +               goto out;
>> +
>> +       error = 0;
>> +       tag_ops[type] = ops;
>> +
>> +out:
>> +       mutex_unlock(&sysfs_rename_mutex);
>> +       return error;
>> +}
>> +
>> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
>> +{
>> +       /* Allow the tag to go away while sysfs is still mounted. */
>> +       struct super_block *sb;
>> +       mutex_lock(&sysfs_rename_mutex);
>> +       sysfs_grab_supers();
>> +       mutex_lock(&sysfs_mutex);
>> +       list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
>> +               struct sysfs_super_info *info = sysfs_info(sb);
>> +               if (info->tag[type] != tag)
>> +                       continue;
>> +               info->tag[type] = NULL;
>> +       }
>> +       mutex_unlock(&sysfs_mutex);
>> +       sysfs_release_supers();
>> +       mutex_unlock(&sysfs_rename_mutex);
>> +}
>> +
>>  int __init sysfs_init(void)
>>  {
>>        int err = -ENOMEM;
>> diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
>> index a3ba217..54b2e5f 100644
>> --- a/fs/sysfs/symlink.c
>> +++ b/fs/sysfs/symlink.c
>> @@ -119,7 +119,7 @@ void sysfs_remove_link(struct kobject * kobj, const
>> char * name)
>>        else
>>                parent_sd = kobj->sd;
>>  -       sysfs_hash_and_remove(parent_sd, name);
>> +       sysfs_hash_and_remove(kobj, parent_sd, name);
>>  }
>>   static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
>> diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
>> index f0e5ecb..67115ec 100644
>> --- a/fs/sysfs/sysfs.h
>> +++ b/fs/sysfs/sysfs.h
>> @@ -45,6 +45,7 @@ struct sysfs_dirent {
>>        struct sysfs_dirent     *s_sibling;
>>        const char              *s_name;
>>  +       const void              *s_tag;
>>        union {
>>                struct sysfs_elem_dir           s_dir;
>>                struct sysfs_elem_symlink       s_symlink;
>> @@ -67,14 +68,22 @@ struct sysfs_dirent {
>>  #define SYSFS_KOBJ_LINK                        0x0008
>>  #define SYSFS_COPY_NAME                        (SYSFS_DIR |
>> SYSFS_KOBJ_LINK)
>>  -#define SYSFS_FLAG_MASK                        ~SYSFS_TYPE_MASK
>> -#define SYSFS_FLAG_REMOVED             0x0200
>> +#define SYSFS_TAG_TYPE_MASK            0xff00
>> +#define SYSFS_TAG_TYPE_SHIFT           8
>> +
>> +#define SYSFS_FLAG_MASK                        ~(SYSFS_TYPE_MASK |
>> SYSFS_TAG_TYPE_MASK)
>> +#define SYSFS_FLAG_REMOVED             0x020000
>>   static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
>>  {
>>        return sd->s_flags & SYSFS_TYPE_MASK;
>>  }
>>  +static inline enum sysfs_tag_type sysfs_tag_type(struct sysfs_dirent
>> *sd)
>> +{
>> +       return (sd->s_flags & SYSFS_TAG_TYPE_MASK) >>
>> SYSFS_TAG_TYPE_SHIFT;
>> +}
>> +
>>  /*
>>  * Context structure to be used while adding/removing nodes.
>>  */
>> @@ -87,6 +96,7 @@ struct sysfs_addrm_cxt {
>>   struct sysfs_super_info {
>>        int     grabbed;
>> +       const void *tag[SYSFS_TAG_TYPES];
>>  };
>>   #define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
>> @@ -98,6 +108,7 @@ extern struct sysfs_dirent sysfs_root;
>>  extern struct super_block *sysfs_sb;
>>  extern struct kmem_cache *sysfs_dir_cachep;
>>  extern struct file_system_type sysfs_fs_type;
>> +extern struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
>>   void sysfs_grab_supers(void);
>>  void sysfs_release_supers(void);
>> @@ -124,6 +135,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
>> struct sysfs_dirent *sd);
>>  void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
>>   struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
>> +                                      const void *tag,
>>                                       const unsigned char *name);
>>  struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
>>                                      const unsigned char *name);
>> @@ -158,7 +170,8 @@ static inline void __sysfs_put(struct sysfs_dirent
>> *sd)
>>  struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
>>  int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct
>> iattr *iattr);
>>  int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
>> -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
>> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent
>> *dir_sd,
>> +                         const char *name);
>>  int sysfs_inode_init(void);
>>   /*
>> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
>> index 5437ac0..beb3573 100644
>> --- a/include/linux/kobject.h
>> +++ b/include/linux/kobject.h
>> @@ -105,6 +105,7 @@ struct kobj_type {
>>        void (*release)(struct kobject *kobj);
>>        struct sysfs_ops *sysfs_ops;
>>        struct attribute **default_attrs;
>> +       const void *(*sysfs_tag)(struct kobject *kobj);
>>  };
>>   struct kobj_uevent_env {
>> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
>> index d8e0230..ba68829 100644
>> --- a/include/linux/sysfs.h
>> +++ b/include/linux/sysfs.h
>> @@ -80,6 +80,15 @@ struct sysfs_ops {
>>   struct sysfs_dirent;
>>  +enum sysfs_tag_type {
>> +       SYSFS_TAG_TYPE_NONE = 0,
>> +       SYSFS_TAG_TYPES
>> +};
>> +
>> +struct sysfs_tag_type_operations {
>> +       const void *(*mount_tag)(void);
>> +};
>> +
>>  #ifdef CONFIG_SYSFS
>>   int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
>> @@ -126,6 +135,12 @@ struct sysfs_dirent *sysfs_get_dirent(struct
>> sysfs_dirent *parent_sd,
>>  struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
>>  void sysfs_put(struct sysfs_dirent *sd);
>>  void sysfs_printk_last_file(void);
>> +
>> +int sysfs_make_tagged_dir(struct kobject *, enum sysfs_tag_type
>> tag_type);
>> +int sysfs_register_tag_type(enum sysfs_tag_type type,
>> +                           struct sysfs_tag_type_operations *ops);
>> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag);
>> +
>>  int __must_check sysfs_init(void);
>>   #else /* CONFIG_SYSFS */
>> @@ -249,6 +264,22 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
>>  {
>>  }
>>  +staticn inline int sysfs_make_tagged_dir(struct kobject *kobj,
>
>   ______^
>
> This typo is still present in your patch in the CONFIG_SYSFS=n case.
>
> Otherwise the patchset, combined with the patches Greg has already
> merged in his tree, still works great for me with network namespaces.
>
> --Benjamin
>
>> +                                               enum sysfs_tag_type
>> tag_type)
>> +{
>> +       return 0;
>> +}
>> +
>> +static inline int sysfs_register_tag_type(enum sysfs_tag_type type,
>> +                                       struct sysfs_tag_type_operations
>> *ops)
>> +{
>> +       return 0;
>> +}
>> +
>> +static inline void sysfs_exit_tag(enum sysfs_tag_type type, const void
>> *tag)
>> +{
>> +}
>> +
>>  static inline int __must_check sysfs_init(void)
>>  {
>>        return 0;
>
>
> --
> B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D
>
>   http://www.bull.com
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Benjamin Thery]

Mark Ryden wrote:
> Hello,
>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
> it for example in linux-net (I have an up-to-date linux-next git
> tree).

I was about to ask the same thing.

Greg, what is the plan with these remaining patches for sysfs tagged
dirs? Will you have some time to merge them in your tree soon?

I ran my network namespace tests last week with this latest patchset
from Eric applied on top of your tree (which already contains the first
batch of patches). Everything looked good.

Regards,
Benjamin


> 
> Regards,
> Mark
> 
> On Wed, Aug 27, 2008 at 6:18 PM, Benjamin Thery <benjamin.thery@bull.net> wrote:
>> Eric W. Biederman wrote:
>>> The problem.  When implementing a network namespace I need to be able
>>> to have multiple network devices with the same name.  Currently this
>>> is a problem for /sys/class/net/*, /sys/devices/virtual/net/*, and
>>> potentially a few other directories of the form /sys/ ... /net/*.
>>>
>>> What this patch does is to add an additional tag field to the
>>> sysfs dirent structure.  For directories that should show different
>>> contents depending on the context such as /sys/class/net/, and
>>> /sys/devices/virtual/net/ this tag field is used to specify the
>>> context in which those directories should be visible.  Effectively
>>> this is the same as creating multiple distinct directories with
>>> the same name but internally to sysfs the result is nicer.
>>>
>>> I am calling the concept of a single directory that looks like multiple
>>> directories all at the same path in the filesystem tagged directories.
>>>
>>> For the networking namespace the set of directories whose contents I need
>>> to filter with tags can depend on the presence or absence of hotplug
>>> hardware or which modules are currently loaded.  Which means I need
>>> a simple race free way to setup those directories as tagged.
>>>
>>> To achieve a reace free design all tagged directories are created
>>> and managed by sysfs itself.
>>>
>>> Users of this interface:
>>> - define a type in the sysfs_tag_type enumeration.
>>> - call sysfs_register_tag_types with the type and it's operations
>>> - call sysfs_make_tagged_dir with the tag type on directories
>>>  to be managed by this tag type
>>> - sysfs_exit_tag when an individual tag is no longer valid
>>>
>>> - Implement mount_tag() which returns the tag of the calling process
>>>  so we can attach it to a sysfs superblock.
>>> - Implement ktype.sysfs_tag() which returns the tag of a syfs kobject.
>>>
>>> Everything else is left up to sysfs and the driver layer.
>>>
>>> For the network namespace mount_tag and sysfs_tag are essentially
>>> one line functions, and look to remain that.
>>>
>>> Tags are currently represented a const void * pointers as that is
>>> both generic, prevides enough information for equality comparisons,
>>> and is trivial to create for current users, as it is just the
>>> existing namespace pointer.
>>>
>>> The work needed in sysfs is more extensive.  At each directory
>>> or symlink creating I need to check if the directory it is being
>>> created in is a tagged directory and if so generate the appropriate
>>> tag to place on the sysfs_dirent.  Likewise at each symlink or
>>> directory removal I need to check if the sysfs directory it is
>>> being removed from is a tagged directory and if so figure out
>>> which tag goes along with the name I am deleting.
>>>
>>> Currently only directories which hold kobjects, and
>>> symlinks are supported.  There is not enough information
>>> in the current file attribute interfaces to give us anything
>>> to discriminate on which makes it useless, and there are
>>> no potential users which makes it an uninteresting problem
>>> to solve.
>>>
>>> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>>> Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
>>> ---
>>>  fs/sysfs/bin.c          |    2 +-
>>>  fs/sysfs/dir.c          |  139
>>> ++++++++++++++++++++++++++++++++++++++++++-----
>>>  fs/sysfs/file.c         |   11 +++--
>>>  fs/sysfs/group.c        |    4 +-
>>>  fs/sysfs/inode.c        |    7 ++-
>>>  fs/sysfs/mount.c        |  115 +++++++++++++++++++++++++++++++++++++--
>>>  fs/sysfs/symlink.c      |    2 +-
>>>  fs/sysfs/sysfs.h        |   19 ++++++-
>>>  include/linux/kobject.h |    1 +
>>>  include/linux/sysfs.h   |   31 +++++++++++
>>>  10 files changed, 298 insertions(+), 33 deletions(-)
>>>
>>> diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
>>> index 006fc64..86e1128 100644
>>> --- a/fs/sysfs/bin.c
>>> +++ b/fs/sysfs/bin.c
>>> @@ -252,7 +252,7 @@ int sysfs_create_bin_file(struct kobject * kobj,
>>> struct bin_attribute * attr)
>>>   void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute *
>>> attr)
>>>  {
>>> -       sysfs_hash_and_remove(kobj->sd, attr->attr.name);
>>> +       sysfs_hash_and_remove(kobj, kobj->sd, attr->attr.name);
>>>  }
>>>   EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
>>> diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
>>> index 4ffcfd2..dec7586 100644
>>> --- a/fs/sysfs/dir.c
>>> +++ b/fs/sysfs/dir.c
>>> @@ -30,6 +30,30 @@ DEFINE_SPINLOCK(sysfs_assoc_lock);
>>>  static DEFINE_SPINLOCK(sysfs_ino_lock);
>>>  static DEFINE_IDA(sysfs_ino_ida);
>>>  +static const void *sysfs_creation_tag(struct sysfs_dirent *parent_sd,
>>> +                                     struct sysfs_dirent *sd)
>>> +{
>>> +       const void *tag = NULL;
>>> +
>>> +       if (sysfs_tag_type(parent_sd)) {
>>> +               struct kobject *kobj;
>>> +               switch (sysfs_type(sd)) {
>>> +               case SYSFS_DIR:
>>> +                       kobj = sd->s_dir.kobj;
>>> +                       break;
>>> +               case SYSFS_KOBJ_LINK:
>>> +                       kobj = sd->s_symlink.target_sd->s_dir.kobj;
>>> +                       break;
>>> +               default:
>>> +                       BUG();
>>> +               }
>>> +               tag = kobj->ktype->sysfs_tag(kobj);
>>> +               /* NULL tags are reserved for internal use */
>>> +               BUG_ON(tag == NULL);
>>> +       }
>>> +       return tag;
>>> +}
>>> +
>>>  /**
>>>  *     sysfs_link_sibling - link sysfs_dirent into sibling list
>>>  *     @sd: sysfs_dirent of interest
>>> @@ -101,8 +125,19 @@ static void sysfs_unlink_sibling(struct sysfs_dirent
>>> *sd)
>>>  struct dentry *sysfs_get_dentry(struct super_block *sb,
>>>                                struct sysfs_dirent *sd)
>>>  {
>>> -       struct dentry *dentry = dget(sb->s_root);
>>> +       struct dentry *dentry;
>>> +
>>> +       /* Bail if this sd won't show up in this superblock */
>>> +       if (sd->s_parent) {
>>> +               enum sysfs_tag_type type;
>>> +               const void *tag;
>>> +               type = sysfs_tag_type(sd->s_parent);
>>> +               tag = sysfs_info(sb)->tag[type];
>>> +               if (sd->s_tag != tag)
>>> +                       return ERR_PTR(-EXDEV);
>>> +       }
>>>  +       dentry = dget(sb->s_root);
>>>        while (dentry->d_fsdata != sd) {
>>>                struct sysfs_dirent *cur;
>>>                struct dentry *parent;
>>> @@ -421,10 +456,15 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
>>>  */
>>>  int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent
>>> *sd)
>>>  {
>>> -       if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
>>> +       const void *tag = NULL;
>>> +
>>> +       tag = sysfs_creation_tag(acxt->parent_sd, sd);
>>> +
>>> +       if (sysfs_find_dirent(acxt->parent_sd, tag, sd->s_name))
>>>                return -EEXIST;
>>>          sd->s_parent = sysfs_get(acxt->parent_sd);
>>> +       sd->s_tag = tag;
>>>          if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
>>>                inc_nlink(acxt->parent_inode);
>>> @@ -602,13 +642,17 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt
>>> *acxt)
>>>  *     Pointer to sysfs_dirent if found, NULL if not.
>>>  */
>>>  struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
>>> +                                      const void *tag,
>>>                                       const unsigned char *name)
>>>  {
>>>        struct sysfs_dirent *sd;
>>>  -       for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling)
>>> +       for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) {
>>> +               if (sd->s_tag != tag)
>>> +                       continue;
>>>                if (!strcmp(sd->s_name, name))
>>>                        return sd;
>>> +       }
>>>        return NULL;
>>>  }
>>>  @@ -632,7 +676,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct
>>> sysfs_dirent *parent_sd,
>>>        struct sysfs_dirent *sd;
>>>          mutex_lock(&sysfs_mutex);
>>> -       sd = sysfs_find_dirent(parent_sd, name);
>>> +       sd = sysfs_find_dirent(parent_sd, NULL, name);
>>>        sysfs_get(sd);
>>>        mutex_unlock(&sysfs_mutex);
>>>  @@ -699,13 +743,18 @@ static struct dentry * sysfs_lookup(struct inode
>>> *dir, struct dentry *dentry,
>>>                                struct nameidata *nd)
>>>  {
>>>        struct dentry *ret = NULL;
>>> -       struct sysfs_dirent *parent_sd = dentry->d_parent->d_fsdata;
>>> +       struct dentry *parent = dentry->d_parent;
>>> +       struct sysfs_dirent *parent_sd = parent->d_fsdata;
>>>        struct sysfs_dirent *sd;
>>>        struct inode *inode;
>>> +       enum sysfs_tag_type type;
>>> +       const void *tag;
>>>          mutex_lock(&sysfs_mutex);
>>>  -       sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);
>>> +       type = sysfs_tag_type(parent_sd);
>>> +       tag = sysfs_info(parent->d_sb)->tag[type];
>>> +       sd = sysfs_find_dirent(parent_sd, tag, dentry->d_name.name);
>>>          /* no such entry */
>>>        if (!sd) {
>>> @@ -913,19 +962,24 @@ int sysfs_rename_dir(struct kobject * kobj, const
>>> char *new_name)
>>>        struct sysfs_rename_struct *srs;
>>>        struct inode *parent_inode = NULL;
>>>        const char *dup_name = NULL;
>>> +       const void *old_tag, *tag;
>>>        int error;
>>>          INIT_LIST_HEAD(&todo);
>>>        mutex_lock(&sysfs_rename_mutex);
>>> +       old_tag = sd->s_tag;
>>> +       tag = sysfs_creation_tag(sd->s_parent, sd);
>>>          error = 0;
>>> -       if (strcmp(sd->s_name, new_name) == 0)
>>> +       if ((old_tag == tag) && (strcmp(sd->s_name, new_name) == 0))
>>>                goto out;       /* nothing to rename */
>>>          sysfs_grab_supers();
>>> -       error = prep_rename(&todo, sd, sd->s_parent, new_name);
>>> -       if (error)
>>> -               goto out_release;
>>> +       if (old_tag == tag) {
>>> +               error = prep_rename(&todo, sd, sd->s_parent, new_name);
>>> +               if (error)
>>> +                       goto out_release;
>>> +       }
>>>          error = -ENOMEM;
>>>        mutex_lock(&sysfs_mutex);
>>> @@ -938,7 +992,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char
>>> *new_name)
>>>        mutex_lock(&sysfs_mutex);
>>>          error = -EEXIST;
>>> -       if (sysfs_find_dirent(sd->s_parent, new_name))
>>> +       if (sysfs_find_dirent(sd->s_parent, tag, new_name))
>>>                goto out_unlock;
>>>          /* rename sysfs_dirent */
>>> @@ -949,6 +1003,7 @@ int sysfs_rename_dir(struct kobject * kobj, const
>>> char *new_name)
>>>          dup_name = sd->s_name;
>>>        sd->s_name = new_name;
>>> +       sd->s_tag = tag;
>>>          /* rename */
>>>        list_for_each_entry(srs, &todo, list) {
>>> @@ -956,6 +1011,20 @@ int sysfs_rename_dir(struct kobject * kobj, const
>>> char *new_name)
>>>                d_move(srs->old_dentry, srs->new_dentry);
>>>        }
>>>  +       /* If we are moving across superblocks drop the dcache entries */
>>> +       if (old_tag != tag) {
>>> +               struct super_block *sb;
>>> +               struct dentry *dentry;
>>> +               list_for_each_entry(sb, &sysfs_fs_type.fs_supers,
>>> s_instances) {
>>> +                       dentry = __sysfs_get_dentry(sb, sd);
>>> +                       if (!dentry)
>>> +                               continue;
>>> +                       shrink_dcache_parent(dentry);
>>> +                       d_drop(dentry);
>>> +                       dput(dentry);
>>> +               }
>>> +       }
>>> +
>>>        error = 0;
>>>  out_unlock:
>>>        mutex_unlock(&sysfs_mutex);
>>> @@ -978,11 +1047,13 @@ int sysfs_move_dir(struct kobject *kobj, struct
>>> kobject *new_parent_kobj)
>>>        struct sysfs_rename_struct *srs;
>>>        struct inode *old_parent_inode = NULL, *new_parent_inode = NULL;
>>>        int error;
>>> +       const void *tag;
>>>          INIT_LIST_HEAD(&todo);
>>>        mutex_lock(&sysfs_rename_mutex);
>>>        BUG_ON(!sd->s_parent);
>>>        new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd :
>>> &sysfs_root;
>>> +       tag = sd->s_tag;
>>>          error = 0;
>>>        if (sd->s_parent == new_parent_sd)
>>> @@ -1016,7 +1087,7 @@ again:
>>>        mutex_lock(&sysfs_mutex);
>>>          error = -EEXIST;
>>> -       if (sysfs_find_dirent(new_parent_sd, sd->s_name))
>>> +       if (sysfs_find_dirent(new_parent_sd, tag, sd->s_name))
>>>                goto out_unlock;
>>>          error = 0;
>>> @@ -1055,10 +1126,12 @@ static inline unsigned char dt_type(struct
>>> sysfs_dirent *sd)
>>>   static int sysfs_readdir(struct file * filp, void * dirent, filldir_t
>>> filldir)
>>>  {
>>> -       struct dentry *dentry = filp->f_path.dentry;
>>> -       struct sysfs_dirent * parent_sd = dentry->d_fsdata;
>>> +       struct dentry *parent = filp->f_path.dentry;
>>> +       struct sysfs_dirent *parent_sd = parent->d_fsdata;
>>>        struct sysfs_dirent *pos;
>>>        ino_t ino;
>>> +       enum sysfs_tag_type type;
>>> +       const void *tag;
>>>          if (filp->f_pos == 0) {
>>>                ino = parent_sd->s_ino;
>>> @@ -1076,6 +1149,9 @@ static int sysfs_readdir(struct file * filp, void *
>>> dirent, filldir_t filldir)
>>>        if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
>>>                mutex_lock(&sysfs_mutex);
>>>  +               type = sysfs_tag_type(parent_sd);
>>> +               tag = sysfs_info(parent->d_sb)->tag[type];
>>> +
>>>                /* Skip the dentries we have already reported */
>>>                pos = parent_sd->s_dir.children;
>>>                while (pos && (filp->f_pos > pos->s_ino))
>>> @@ -1085,6 +1161,9 @@ static int sysfs_readdir(struct file * filp, void *
>>> dirent, filldir_t filldir)
>>>                        const char * name;
>>>                        int len;
>>>  +                       if (pos->s_tag != tag)
>>> +                               continue;
>>> +
>>>                        name = pos->s_name;
>>>                        len = strlen(name);
>>>                        filp->f_pos = ino = pos->s_ino;
>>> @@ -1105,3 +1184,35 @@ const struct file_operations sysfs_dir_operations =
>>> {
>>>        .read           = generic_read_dir,
>>>        .readdir        = sysfs_readdir,
>>>  };
>>> +
>>> +/**
>>> + *     sysfs_make_tagged_dir - Require tags of all the entries in a
>>> directory.
>>> + *     @kobj:  object whose children should be filtered by tags
>>> + *
>>> + *     Once tagging has been enabled on a directory the contents
>>> + *     of the directory become dependent upon context captured when
>>> + *     sysfs was mounted.
>>> + */
>>> +int sysfs_make_tagged_dir(struct kobject *kobj, enum sysfs_tag_type type)
>>> +{
>>> +       struct sysfs_dirent *sd;
>>> +       int err;
>>> +
>>> +       err = -ENOENT;
>>> +       sd = kobj->sd;
>>> +
>>> +       mutex_lock(&sysfs_mutex);
>>> +       err = -EINVAL;
>>> +       /* We can only enable tagging when we have a valid tag type
>>> +        * on empty directories where taggint has not already been
>>> +        * enabled.
>>> +        */
>>> +       if ((type > SYSFS_TAG_TYPE_NONE) && (type < SYSFS_TAG_TYPES) &&
>>> +           tag_ops[type] && !sysfs_tag_type(sd) &&
>>> +           (sysfs_type(sd) == SYSFS_DIR) && !sd->s_dir.children) {
>>> +               err = 0;
>>> +               sd->s_flags |= (type << SYSFS_TAG_TYPE_SHIFT);
>>> +       }
>>> +       mutex_unlock(&sysfs_mutex);
>>> +       return err;
>>> +}
>>> diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
>>> index 61c3476..091c0de 100644
>>> --- a/fs/sysfs/file.c
>>> +++ b/fs/sysfs/file.c
>>> @@ -476,9 +476,12 @@ void sysfs_notify(struct kobject *k, char *dir, char
>>> *attr)
>>>        mutex_lock(&sysfs_mutex);
>>>          if (sd && dir)
>>> -               sd = sysfs_find_dirent(sd, dir);
>>> +               /* Only directories are tagged, so no need to pass
>>> +                * a tag explicitly.
>>> +                */
>>> +               sd = sysfs_find_dirent(sd, NULL, dir);
>>>        if (sd && attr)
>>> -               sd = sysfs_find_dirent(sd, attr);
>>> +               sd = sysfs_find_dirent(sd, NULL, attr);
>>>        if (sd)
>>>                sysfs_notify_dirent(sd);
>>>  @@ -640,7 +643,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file);
>>>   void sysfs_remove_file(struct kobject * kobj, const struct attribute *
>>> attr)
>>>  {
>>> -       sysfs_hash_and_remove(kobj->sd, attr->name);
>>> +       sysfs_hash_and_remove(kobj, kobj->sd, attr->name);
>>>  }
>>>   @@ -660,7 +663,7 @@ void sysfs_remove_file_from_group(struct kobject
>>> *kobj,
>>>        else
>>>                dir_sd = sysfs_get(kobj->sd);
>>>        if (dir_sd) {
>>> -               sysfs_hash_and_remove(dir_sd, attr->name);
>>> +               sysfs_hash_and_remove(kobj, dir_sd, attr->name);
>>>                sysfs_put(dir_sd);
>>>        }
>>>  }
>>> diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
>>> index fe61194..5fba6f2 100644
>>> --- a/fs/sysfs/group.c
>>> +++ b/fs/sysfs/group.c
>>> @@ -23,7 +23,7 @@ static void remove_files(struct sysfs_dirent *dir_sd,
>>> struct kobject *kobj,
>>>        int i;
>>>          for (i = 0, attr = grp->attrs; *attr; i++, attr++)
>>> -               sysfs_hash_and_remove(dir_sd, (*attr)->name);
>>> +               sysfs_hash_and_remove(kobj, dir_sd, (*attr)->name);
>>>  }
>>>   static int create_files(struct sysfs_dirent *dir_sd, struct kobject
>>> *kobj,
>>> @@ -39,7 +39,7 @@ static int create_files(struct sysfs_dirent *dir_sd,
>>> struct kobject *kobj,
>>>                 * visibility.  Do this by first removing then
>>>                 * re-adding (if required) the file */
>>>                if (update)
>>> -                       sysfs_hash_and_remove(dir_sd, (*attr)->name);
>>> +                       sysfs_hash_and_remove(kobj, dir_sd,
>>> (*attr)->name);
>>>                if (grp->is_visible) {
>>>                        mode = grp->is_visible(kobj, *attr, i);
>>>                        if (!mode)
>>> diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
>>> index 80f8fd4..b5fc78a 100644
>>> --- a/fs/sysfs/inode.c
>>> +++ b/fs/sysfs/inode.c
>>> @@ -226,17 +226,20 @@ struct inode * sysfs_get_inode(struct sysfs_dirent
>>> *sd)
>>>        return inode;
>>>  }
>>>  -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
>>> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent
>>> *dir_sd,
>>> +                         const char *name)
>>>  {
>>>        struct sysfs_addrm_cxt acxt;
>>>        struct sysfs_dirent *sd;
>>> +       const void *tag;
>>>          if (!dir_sd)
>>>                return -ENOENT;
>>>          sysfs_addrm_start(&acxt, dir_sd);
>>> +       tag = kobj->sd->s_tag;
>>>  -       sd = sysfs_find_dirent(dir_sd, name);
>>> +       sd = sysfs_find_dirent(dir_sd, tag, name);
>>>        if (sd)
>>>                sysfs_remove_one(&acxt, sd);
>>>  diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
>>> index 6ebda1a..8f2237a 100644
>>> --- a/fs/sysfs/mount.c
>>> +++ b/fs/sysfs/mount.c
>>> @@ -35,12 +35,15 @@ static const struct super_operations sysfs_ops = {
>>>  struct sysfs_dirent sysfs_root = {
>>>        .s_name         = "",
>>>        .s_count        = ATOMIC_INIT(1),
>>> -       .s_flags        = SYSFS_DIR,
>>> +       .s_flags        = SYSFS_DIR | (SYSFS_TAG_TYPE_NONE <<
>>> SYSFS_TAG_TYPE_SHIFT),
>>>        .s_mode         = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
>>>        .s_ino          = 1,
>>>  };
>>>  -static int sysfs_fill_super(struct super_block *sb, void *data, int
>>> silent)
>>> +struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
>>> +
>>> +static int sysfs_fill_super(struct super_block *sb, void *data, int
>>> silent,
>>> +       const void *tags[SYSFS_TAG_TYPES])
>>>  {
>>>        struct sysfs_super_info *info = NULL;
>>>        struct inode *inode = NULL;
>>> @@ -76,8 +79,10 @@ static int sysfs_fill_super(struct super_block *sb,
>>> void *data, int silent)
>>>                goto out_err;
>>>        }
>>>        root->d_fsdata = &sysfs_root;
>>> +       root->d_sb = sb;
>>>        sb->s_root = root;
>>>        sb->s_fs_info = info;
>>> +       memcpy(info->tag, tags, sizeof(info->tag[0])*SYSFS_TAG_TYPES);
>>>        return 0;
>>>   out_err:
>>> @@ -89,20 +94,74 @@ out_err:
>>>        return error;
>>>  }
>>>  +static int sysfs_test_super(struct super_block *sb, void *ptr)
>>> +{
>>> +       const void **tag = ptr;
>>> +       struct sysfs_super_info *info = sysfs_info(sb);
>>> +       enum sysfs_tag_type type;
>>> +       int found = 1;
>>> +
>>> +       for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
>>> +               if (info->tag[type] != tag[type]) {
>>> +                       found = 0;
>>> +                       break;
>>> +               }
>>> +       }
>>> +
>>> +       return found;
>>> +}
>>> +
>>>  static int sysfs_get_sb(struct file_system_type *fs_type,
>>>        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
>>>  {
>>> -       int rc;
>>> +       const void *tag[SYSFS_TAG_TYPES];
>>> +       struct super_block *sb;
>>> +       int error;
>>> +       enum sysfs_tag_type type;
>>> +
>>> +       for (type = SYSFS_TAG_TYPE_NONE; type < SYSFS_TAG_TYPES; type++) {
>>> +               tag[type] = NULL;
>>> +               if (!tag_ops[type])
>>> +                       continue;
>>> +               tag[type] = tag_ops[type]->mount_tag();
>>> +       }
>>> +
>>>        mutex_lock(&sysfs_rename_mutex);
>>> -       rc = get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
>>> +       sb = sget(fs_type, sysfs_test_super, set_anon_super, tag);
>>> +       if (IS_ERR(sb)) {
>>> +               error = PTR_ERR(sb);
>>> +               goto out;
>>> +       }
>>> +       if (!sb->s_root) {
>>> +               sb->s_flags = flags;
>>> +               error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 :
>>> 0,
>>> +                                       tag);
>>> +               if (error) {
>>> +                       up_write(&sb->s_umount);
>>> +                       deactivate_super(sb);
>>> +                       goto out;
>>> +               }
>>> +               sb->s_flags |= MS_ACTIVE;
>>> +       }
>>> +       do_remount_sb(sb, flags, data, 0);
>>> +       error = simple_set_mnt(mnt, sb);
>>> +out:
>>>        mutex_unlock(&sysfs_rename_mutex);
>>> -       return rc;
>>> +       return error;
>>> +}
>>> +
>>> +static void sysfs_kill_sb(struct super_block *sb)
>>> +{
>>> +       struct sysfs_super_info *info = sysfs_info(sb);
>>> +
>>> +       kill_anon_super(sb);
>>> +       kfree(info);
>>>  }
>>>   struct file_system_type sysfs_fs_type = {
>>>        .name           = "sysfs",
>>>        .get_sb         = sysfs_get_sb,
>>> -       .kill_sb        = kill_anon_super,
>>> +       .kill_sb        = sysfs_kill_sb,
>>>  };
>>>   void sysfs_grab_supers(void)
>>> @@ -146,6 +205,50 @@ restart:
>>>        spin_unlock(&sb_lock);
>>>  }
>>>  +int sysfs_register_tag_type(enum sysfs_tag_type type, struct
>>> sysfs_tag_type_operations *ops)
>>> +{
>>> +       int error;
>>> +
>>> +       mutex_lock(&sysfs_rename_mutex);
>>> +
>>> +       error = -EINVAL;
>>> +       if (type >= SYSFS_TAG_TYPES)
>>> +               goto out;
>>> +
>>> +       error = -EINVAL;
>>> +       if (type <= SYSFS_TAG_TYPE_NONE)
>>> +               goto out;
>>> +
>>> +       error = -EBUSY;
>>> +       if (tag_ops[type])
>>> +               goto out;
>>> +
>>> +       error = 0;
>>> +       tag_ops[type] = ops;
>>> +
>>> +out:
>>> +       mutex_unlock(&sysfs_rename_mutex);
>>> +       return error;
>>> +}
>>> +
>>> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag)
>>> +{
>>> +       /* Allow the tag to go away while sysfs is still mounted. */
>>> +       struct super_block *sb;
>>> +       mutex_lock(&sysfs_rename_mutex);
>>> +       sysfs_grab_supers();
>>> +       mutex_lock(&sysfs_mutex);
>>> +       list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
>>> +               struct sysfs_super_info *info = sysfs_info(sb);
>>> +               if (info->tag[type] != tag)
>>> +                       continue;
>>> +               info->tag[type] = NULL;
>>> +       }
>>> +       mutex_unlock(&sysfs_mutex);
>>> +       sysfs_release_supers();
>>> +       mutex_unlock(&sysfs_rename_mutex);
>>> +}
>>> +
>>>  int __init sysfs_init(void)
>>>  {
>>>        int err = -ENOMEM;
>>> diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
>>> index a3ba217..54b2e5f 100644
>>> --- a/fs/sysfs/symlink.c
>>> +++ b/fs/sysfs/symlink.c
>>> @@ -119,7 +119,7 @@ void sysfs_remove_link(struct kobject * kobj, const
>>> char * name)
>>>        else
>>>                parent_sd = kobj->sd;
>>>  -       sysfs_hash_and_remove(parent_sd, name);
>>> +       sysfs_hash_and_remove(kobj, parent_sd, name);
>>>  }
>>>   static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
>>> diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
>>> index f0e5ecb..67115ec 100644
>>> --- a/fs/sysfs/sysfs.h
>>> +++ b/fs/sysfs/sysfs.h
>>> @@ -45,6 +45,7 @@ struct sysfs_dirent {
>>>        struct sysfs_dirent     *s_sibling;
>>>        const char              *s_name;
>>>  +       const void              *s_tag;
>>>        union {
>>>                struct sysfs_elem_dir           s_dir;
>>>                struct sysfs_elem_symlink       s_symlink;
>>> @@ -67,14 +68,22 @@ struct sysfs_dirent {
>>>  #define SYSFS_KOBJ_LINK                        0x0008
>>>  #define SYSFS_COPY_NAME                        (SYSFS_DIR |
>>> SYSFS_KOBJ_LINK)
>>>  -#define SYSFS_FLAG_MASK                        ~SYSFS_TYPE_MASK
>>> -#define SYSFS_FLAG_REMOVED             0x0200
>>> +#define SYSFS_TAG_TYPE_MASK            0xff00
>>> +#define SYSFS_TAG_TYPE_SHIFT           8
>>> +
>>> +#define SYSFS_FLAG_MASK                        ~(SYSFS_TYPE_MASK |
>>> SYSFS_TAG_TYPE_MASK)
>>> +#define SYSFS_FLAG_REMOVED             0x020000
>>>   static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
>>>  {
>>>        return sd->s_flags & SYSFS_TYPE_MASK;
>>>  }
>>>  +static inline enum sysfs_tag_type sysfs_tag_type(struct sysfs_dirent
>>> *sd)
>>> +{
>>> +       return (sd->s_flags & SYSFS_TAG_TYPE_MASK) >>
>>> SYSFS_TAG_TYPE_SHIFT;
>>> +}
>>> +
>>>  /*
>>>  * Context structure to be used while adding/removing nodes.
>>>  */
>>> @@ -87,6 +96,7 @@ struct sysfs_addrm_cxt {
>>>   struct sysfs_super_info {
>>>        int     grabbed;
>>> +       const void *tag[SYSFS_TAG_TYPES];
>>>  };
>>>   #define sysfs_info(SB) ((struct sysfs_super_info *)(SB)->s_fs_info)
>>> @@ -98,6 +108,7 @@ extern struct sysfs_dirent sysfs_root;
>>>  extern struct super_block *sysfs_sb;
>>>  extern struct kmem_cache *sysfs_dir_cachep;
>>>  extern struct file_system_type sysfs_fs_type;
>>> +extern struct sysfs_tag_type_operations *tag_ops[SYSFS_TAG_TYPES];
>>>   void sysfs_grab_supers(void);
>>>  void sysfs_release_supers(void);
>>> @@ -124,6 +135,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
>>> struct sysfs_dirent *sd);
>>>  void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
>>>   struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
>>> +                                      const void *tag,
>>>                                       const unsigned char *name);
>>>  struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
>>>                                      const unsigned char *name);
>>> @@ -158,7 +170,8 @@ static inline void __sysfs_put(struct sysfs_dirent
>>> *sd)
>>>  struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
>>>  int sysfs_sd_setattr(struct sysfs_dirent *sd, struct inode *inode, struct
>>> iattr *iattr);
>>>  int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
>>> -int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name);
>>> +int sysfs_hash_and_remove(struct kobject *kobj, struct sysfs_dirent
>>> *dir_sd,
>>> +                         const char *name);
>>>  int sysfs_inode_init(void);
>>>   /*
>>> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
>>> index 5437ac0..beb3573 100644
>>> --- a/include/linux/kobject.h
>>> +++ b/include/linux/kobject.h
>>> @@ -105,6 +105,7 @@ struct kobj_type {
>>>        void (*release)(struct kobject *kobj);
>>>        struct sysfs_ops *sysfs_ops;
>>>        struct attribute **default_attrs;
>>> +       const void *(*sysfs_tag)(struct kobject *kobj);
>>>  };
>>>   struct kobj_uevent_env {
>>> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
>>> index d8e0230..ba68829 100644
>>> --- a/include/linux/sysfs.h
>>> +++ b/include/linux/sysfs.h
>>> @@ -80,6 +80,15 @@ struct sysfs_ops {
>>>   struct sysfs_dirent;
>>>  +enum sysfs_tag_type {
>>> +       SYSFS_TAG_TYPE_NONE = 0,
>>> +       SYSFS_TAG_TYPES
>>> +};
>>> +
>>> +struct sysfs_tag_type_operations {
>>> +       const void *(*mount_tag)(void);
>>> +};
>>> +
>>>  #ifdef CONFIG_SYSFS
>>>   int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
>>> @@ -126,6 +135,12 @@ struct sysfs_dirent *sysfs_get_dirent(struct
>>> sysfs_dirent *parent_sd,
>>>  struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
>>>  void sysfs_put(struct sysfs_dirent *sd);
>>>  void sysfs_printk_last_file(void);
>>> +
>>> +int sysfs_make_tagged_dir(struct kobject *, enum sysfs_tag_type
>>> tag_type);
>>> +int sysfs_register_tag_type(enum sysfs_tag_type type,
>>> +                           struct sysfs_tag_type_operations *ops);
>>> +void sysfs_exit_tag(enum sysfs_tag_type type, const void *tag);
>>> +
>>>  int __must_check sysfs_init(void);
>>>   #else /* CONFIG_SYSFS */
>>> @@ -249,6 +264,22 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
>>>  {
>>>  }
>>>  +staticn inline int sysfs_make_tagged_dir(struct kobject *kobj,
>>   ______^
>>
>> This typo is still present in your patch in the CONFIG_SYSFS=n case.
>>
>> Otherwise the patchset, combined with the patches Greg has already
>> merged in his tree, still works great for me with network namespaces.
>>
>> --Benjamin
>>
>>> +                                               enum sysfs_tag_type
>>> tag_type)
>>> +{
>>> +       return 0;
>>> +}
>>> +
>>> +static inline int sysfs_register_tag_type(enum sysfs_tag_type type,
>>> +                                       struct sysfs_tag_type_operations
>>> *ops)
>>> +{
>>> +       return 0;
>>> +}
>>> +
>>> +static inline void sysfs_exit_tag(enum sysfs_tag_type type, const void
>>> *tag)
>>> +{
>>> +}
>>> +
>>>  static inline int __must_check sysfs_init(void)
>>>  {
>>>        return 0;
>>
>> --
>> B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D
>>
>>   http://www.bull.com
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 
> 


-- 
B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D

    http://www.bull.com

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Greg KH]

On Tue, Sep 02, 2008 at 04:03:20PM +0200, Benjamin Thery wrote:
> Mark Ryden wrote:
>> Hello,
>>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
>> it for example in linux-net (I have an up-to-date linux-next git
>> tree).
>
> I was about to ask the same thing.
>
> Greg, what is the plan with these remaining patches for sysfs tagged
> dirs? Will you have some time to merge them in your tree soon?

Yes, they should go into my tree this week, sorry been busy with 2.6.27
work and Novell's Hackweek.

thanks,

greg k-h

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[David Shwatrz]

Hi,
>go into my tree this week,

I am also interested in this patch; may I ask  - what do you mean by
"my  tree" ?I am a little newbie in the kernel, as you might understand.
I looked into http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
for candidates for this git tree you are talking about.

 May I ask: what is the **exact** URL for this git tree you are talking about ?

Thanks,

Regards,
DS


On Tue, Sep 2, 2008 at 8:01 PM, Greg KH <gregkh@suse.de> wrote:
> On Tue, Sep 02, 2008 at 04:03:20PM +0200, Benjamin Thery wrote:
>> Mark Ryden wrote:
>>> Hello,
>>>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
>>> it for example in linux-net (I have an up-to-date linux-next git
>>> tree).
>>
>> I was about to ask the same thing.
>>
>> Greg, what is the plan with these remaining patches for sysfs tagged
>> dirs? Will you have some time to merge them in your tree soon?
>
> Yes, they should go into my tree this week, sorry been busy with 2.6.27
> work and Novell's Hackweek.
>
> thanks,
>
> greg k-h
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Benjamin Thery]

David Shwatrz wrote:
> Hi,
>> go into my tree this week,
> 
> I am also interested in this patch; may I ask  - what do you mean by
> "my  tree" ?I am a little newbie in the kernel, as you might understand.
> I looked into http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
> for candidates for this git tree you are talking about.
> 
>  May I ask: what is the **exact** URL for this git tree you are talking about ?

Greg's tree is there:
http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=summary

You can clone it from here:
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/patches.git

It contains the patches serie to be applied on top of
linux-2.6 (with 'quilt' for example).

Benjamin

> 
> Thanks,
> 
> Regards,
> DS
> 
> 
> On Tue, Sep 2, 2008 at 8:01 PM, Greg KH <gregkh@suse.de> wrote:
>> On Tue, Sep 02, 2008 at 04:03:20PM +0200, Benjamin Thery wrote:
>>> Mark Ryden wrote:
>>>> Hello,
>>>>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
>>>> it for example in linux-net (I have an up-to-date linux-next git
>>>> tree).
>>> I was about to ask the same thing.
>>>
>>> Greg, what is the plan with these remaining patches for sysfs tagged
>>> dirs? Will you have some time to merge them in your tree soon?
>> Yes, they should go into my tree this week, sorry been busy with 2.6.27
>> work and Novell's Hackweek.
>>
>> thanks,
>>
>> greg k-h
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 
> 


-- 
B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D

    http://www.bull.com

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Mark Ryden]

Hi,
Well, I believe that again it was somehow forgotten or was not applied for
other reasons, since polling the following URL several times in last
days did not
show this patch (url:
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/patches.git)

Regards,
MR




On Thu, Sep 4, 2008 at 9:44 AM, Benjamin Thery <benjamin.thery@bull.net> wrote:
> David Shwatrz wrote:
>>
>> Hi,
>>>
>>> go into my tree this week,
>>
>> I am also interested in this patch; may I ask  - what do you mean by
>> "my  tree" ?I am a little newbie in the kernel, as you might understand.
>> I looked into
>> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
>> for candidates for this git tree you are talking about.
>>
>>  May I ask: what is the **exact** URL for this git tree you are talking
>> about ?
>
> Greg's tree is there:
> http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=summary
>
> You can clone it from here:
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/patches.git
>
> It contains the patches serie to be applied on top of
> linux-2.6 (with 'quilt' for example).
>
> Benjamin
>
>>
>> Thanks,
>>
>> Regards,
>> DS
>>
>>
>> On Tue, Sep 2, 2008 at 8:01 PM, Greg KH <gregkh@suse.de> wrote:
>>>
>>> On Tue, Sep 02, 2008 at 04:03:20PM +0200, Benjamin Thery wrote:
>>>>
>>>> Mark Ryden wrote:
>>>>>
>>>>> Hello,
>>>>>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
>>>>> it for example in linux-net (I have an up-to-date linux-next git
>>>>> tree).
>>>>
>>>> I was about to ask the same thing.
>>>>
>>>> Greg, what is the plan with these remaining patches for sysfs tagged
>>>> dirs? Will you have some time to merge them in your tree soon?
>>>
>>> Yes, they should go into my tree this week, sorry been busy with 2.6.27
>>> work and Novell's Hackweek.
>>>
>>> thanks,
>>>
>>> greg k-h
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>>
>
>
> --
> B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D
>
>   http://www.bull.com
>

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Mark Ryden]

Hello,
  So I wonder: the sysfs tagged directory support patch is in GerKH
tree for more than a month.
I cloned today latest Linus tree (2.6.27-rc9) and
it is not there as far as I can see.
It is also not in linux-next tree (from september).
Now, I wonder what is the process of merging this
GregKH tree ? should I watch the LKML list for a pull request
from GregKH? or will it be first merged into the linux-next tree?

Regards,
Mark


On Thu, Sep 4, 2008 at 8:44 AM, Benjamin Thery <benjamin.thery@bull.net> wrote:
> David Shwatrz wrote:
>>
>> Hi,
>>>
>>> go into my tree this week,
>>
>> I am also interested in this patch; may I ask  - what do you mean by
>> "my  tree" ?I am a little newbie in the kernel, as you might understand.
>> I looked into
>> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
>> for candidates for this git tree you are talking about.
>>
>>  May I ask: what is the **exact** URL for this git tree you are talking
>> about ?
>
> Greg's tree is there:
> http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=summary
>
> You can clone it from here:
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/patches.git
>
> It contains the patches serie to be applied on top of
> linux-2.6 (with 'quilt' for example).
>
> Benjamin
>
>>
>> Thanks,
>>
>> Regards,
>> DS
>>
>>
>> On Tue, Sep 2, 2008 at 8:01 PM, Greg KH <gregkh@suse.de> wrote:
>>>
>>> On Tue, Sep 02, 2008 at 04:03:20PM +0200, Benjamin Thery wrote:
>>>>
>>>> Mark Ryden wrote:
>>>>>
>>>>> Hello,
>>>>>  I hope that this patch (from 4.7.08) was not forgetten... I don't see
>>>>> it for example in linux-net (I have an up-to-date linux-next git
>>>>> tree).
>>>>
>>>> I was about to ask the same thing.
>>>>
>>>> Greg, what is the plan with these remaining patches for sysfs tagged
>>>> dirs? Will you have some time to merge them in your tree soon?
>>>
>>> Yes, they should go into my tree this week, sorry been busy with 2.6.27
>>> work and Novell's Hackweek.
>>>
>>> thanks,
>>>
>>> greg k-h
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>>
>>
>
>
> --
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>
>   http://www.bull.com
>

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Greg KH]

On Tue, Oct 07, 2008 at 06:39:04PM +0200, Mark Ryden wrote:
> Hello,
>   So I wonder: the sysfs tagged directory support patch is in GerKH
> tree for more than a month.

I dropped it from my tree 2 days ago, see the thread on lkml for why.

thanks,

greg k-h

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Daniel Lezcano]

Mark Ryden wrote:
> Hello,
>   So I wonder: the sysfs tagged directory support patch is in GerKH
> tree for more than a month.
> I cloned today latest Linus tree (2.6.27-rc9) and
> it is not there as far as I can see.
> It is also not in linux-next tree (from september).
> Now, I wonder what is the process of merging this
> GregKH tree ? should I watch the LKML list for a pull request
> from GregKH? or will it be first merged into the linux-next tree?

They have been dropped.

http://marc.info/?l=linux-kernel&m=122318517411596&w=2

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:

> On Tue, Oct 07, 2008 at 06:39:04PM +0200, Mark Ryden wrote:
>> Hello,
>>   So I wonder: the sysfs tagged directory support patch is in GerKH
>> tree for more than a month.
>
> I dropped it from my tree 2 days ago, see the thread on lkml for why.

Greg why did you drop it? 

Eric

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Greg KH]

On Tue, Oct 07, 2008 at 01:31:52PM -0700, Eric W. Biederman wrote:
> Greg KH <gregkh@suse.de> writes:
> 
> > On Tue, Oct 07, 2008 at 06:39:04PM +0200, Mark Ryden wrote:
> >> Hello,
> >>   So I wonder: the sysfs tagged directory support patch is in GerKH
> >> tree for more than a month.
> >
> > I dropped it from my tree 2 days ago, see the thread on lkml for why.
> 
> Greg why did you drop it? 

Because Al said it was full of problems and for us not to accept it.

thanks,

greg k-h

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

Greg KH <gregkh@suse.de> writes:

> On Tue, Oct 07, 2008 at 01:31:52PM -0700, Eric W. Biederman wrote:
>> Greg KH <gregkh@suse.de> writes:
>> 
>> > On Tue, Oct 07, 2008 at 06:39:04PM +0200, Mark Ryden wrote:
>> >> Hello,
>> >>   So I wonder: the sysfs tagged directory support patch is in GerKH
>> >> tree for more than a month.
>> >
>> > I dropped it from my tree 2 days ago, see the thread on lkml for why.
>> 
>> Greg why did you drop it? 
>
> Because Al said it was full of problems and for us not to accept it.

Yes. Al found problems.

Al reviewed sysfs with my patchset on top of it.

Al's review found problems in  sysfs with my patchset on top of it.

If you look at what Al found the majority of those problems exist in sysfs
without my patches.

Does the following sound like a workable path going forward?

- Not merge for 2.6.28 (we are to close to the merge window for everyone's comfort).

- Fix the small issues specific to tagged directory support that showed
  up in Al's review (patches sent).

- Keep the patches the entire time in a public tree that merges into
  linux-next so that people treat this code base seriously.

- Resolve the sysfs/vfs lock ordering problem mess that makes
  locking in sysfs excruciatingly difficult.

- Merge other patches to fix Als other issues with sysfs.

- Merge to 2.6.29 or wherever we are.


Eric

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Christoph Hellwig]

On Tue, Oct 07, 2008 at 03:27:12PM -0700, Eric W. Biederman wrote:
> Al reviewed sysfs with my patchset on top of it.
> 
> Al's review found problems in  sysfs with my patchset on top of it.
> 
> If you look at what Al found the majority of those problems exist in sysfs
> without my patches.

And when something is crap your fix it firdt before piling up more shit
on top of it.  And sysfs is a really severe case of that, and you're
piling a _lot_ of shit ontop.

Re: [PATCH 1/8] sysfs: Implement sysfs tagged directory support.

[Eric W. Biederman]

Christoph Hellwig <hch@infradead.org> writes:

> On Tue, Oct 07, 2008 at 03:27:12PM -0700, Eric W. Biederman wrote:
>> Al reviewed sysfs with my patchset on top of it.
>> 
>> Al's review found problems in  sysfs with my patchset on top of it.
>> 
>> If you look at what Al found the majority of those problems exist in sysfs
>> without my patches.
>
> And when something is crap your fix it firdt before piling up more shit
> on top of it.  And sysfs is a really severe case of that, and you're
> piling a _lot_ of shit ontop.

Chistoph, your comments and Al's would have been much more productive
if you have had said:

"I didn't like sysfs because it doesn't do things the way other filesystems
  with similar problems do things.  Can you please use common idioms?
  Making the code easier to read and making the code easier to maintain.
  Some of those constructs look awfully complex can you recheck you code
  and see if there is a simpler way to implement them."

That would have been honest and productive.  As it sits.  I have partially
inaccurate feedback from Al, useless feedback from you, and only my own
tough skin and determination to keep me going..

The fact that you and Al look at the code and can't easily make sense of
is a good sign that the code as written will be hard to maintain.  Al's
recent breakage of sysctl is a good example of that.

Eric