[PATCH 20/75] sysfs: Remove first pass at shadow directory support

Greg Kroah-Hartman
2007-10-12T22:29:49Z

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

While shadow directories appear to be a good idea, the current scheme
of controlling their creation and destruction outside of sysfs appears
to be a locking and maintenance nightmare in the face of sysfs
directories dynamically coming and going. Which can now occur for
directories containing network devices when CONFIG_SYSFS_DEPRECATED is
not set.

This patch removes everything from the initial shadow directory support
that allowed the shadow directory creation to be controlled at a higher
level. So except for a few bits of sysfs_rename_dir everything from
commit b592fcfe7f06c15ec11774b5be7ce0de3aa86e73 is now gone.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/sysfs/dir.c | 167 ++++++----------------------------------------
fs/sysfs/group.c | 1 -
fs/sysfs/inode.c | 10 ---
fs/sysfs/mount.c | 2 +-
fs/sysfs/sysfs.h | 6 --
include/linux/kobject.h | 5 --
include/linux/sysfs.h | 27 +-------
lib/kobject.c | 44 ++-----------
8 files changed, 33 insertions(+), 229 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 86d75e0..837073d 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -569,9 +569,6 @@ static void sysfs_drop_dentry(struct sysfs_dirent *sd)
spin_unlock(&dcache_lock);
spin_unlock(&sysfs_assoc_lock);

- /* dentries for shadowed inodes are pinned, unpin */
- if (dentry && sysfs_is_shadowed_inode(dentry->d_inode))
- dput(dentry);
dput(dentry);

/* adjust nlink and update timestamp */
@@ -723,19 +720,15 @@ int sysfs_create_subdir(struct kobject *kobj, const char *name,
/**
* sysfs_create_dir - create a directory for an object.
* @kobj: object we're creating directory for.
- * @shadow_parent: parent object.
*/
-int sysfs_create_dir(struct kobject *kobj,
- struct sysfs_dirent *shadow_parent_sd)
+int sysfs_create_dir(struct kobject * kobj)
{
struct sysfs_dirent *parent_sd, *sd;
int error = 0;

BUG_ON(!kobj);

- if (shadow_parent_sd)
- parent_sd = shadow_parent_sd;
- else if (kobj->parent)
+ if (kobj->parent)
parent_sd = kobj->parent->sd;
else if (sysfs_mount && sysfs_mount->mnt_sb)
parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata;
@@ -890,45 +883,44 @@ void sysfs_remove_dir(struct kobject * kobj)
__sysfs_remove_dir(sd);
}

-int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
- const char *new_name)
+int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
{
- struct sysfs_dirent *sd = kobj->sd;
- struct dentry *new_parent = NULL;
+ struct sysfs_dirent *sd;
+ struct dentry *parent = NULL;
struct dentry *old_dentry = NULL, *new_dentry = NULL;
+ struct sysfs_dirent *parent_sd;
const char *dup_name = NULL;
int error;

+ if (!kobj->parent)
+ return -EINVAL;
+
/* get dentries */
+ sd = kobj->sd;
old_dentry = sysfs_get_dentry(sd);
if (IS_ERR(old_dentry)) {
error = PTR_ERR(old_dentry);
goto out_dput;
}

- new_parent = sysfs_get_dentry(new_parent_sd);
- if (IS_ERR(new_parent)) {
- error = PTR_ERR(new_parent);
+ parent_sd = kobj->parent->sd;
+ parent = sysfs_get_dentry(parent_sd);
+ if (IS_ERR(parent)) {
+ error = PTR_ERR(parent);
goto out_dput;
}

- /* lock new_parent and get dentry for new name */
- mutex_lock(&new_parent->d_inode->i_mutex);
+ /* lock parent and get dentry for new name */
+ mutex_lock(&parent->d_inode->i_mutex);

- new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
+ new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
if (IS_ERR(new_dentry)) {
error = PTR_ERR(new_dentry);
goto out_unlock;
}

- /* By allowing two different directories with the same
- * d_parent we allow this routine to move between different
- * shadows of the same directory
- */
error = -EINVAL;
- if (old_dentry->d_parent->d_inode != new_parent->d_inode ||
- new_dentry->d_parent->d_inode != new_parent->d_inode ||
- old_dentry == new_dentry)
+ if (old_dentry == new_dentry)
goto out_unlock;

error = -EEXIST;
@@ -955,9 +947,9 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
d_move(sd->s_dentry, new_dentry);

sysfs_unlink_sibling(sd);
- sysfs_get(new_parent_sd);
+ sysfs_get(parent_sd);
sysfs_put(sd->s_parent);
- sd->s_parent = new_parent_sd;
+ sd->s_parent = parent_sd;
sysfs_link_sibling(sd);

mutex_unlock(&sysfs_mutex);
@@ -968,10 +960,10 @@ int sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
out_drop:
d_drop(new_dentry);
out_unlock:
- mutex_unlock(&new_parent->d_inode->i_mutex);
+ mutex_unlock(&parent->d_inode->i_mutex);
out_dput:
kfree(dup_name);
- dput(new_parent);
+ dput(parent);
dput(old_dentry);
dput(new_dentry);
return error;
@@ -1192,121 +1184,6 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
return offset;
}

-
-/**
- * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
- * @kobj: object we're creating shadow of.
- */
-
-int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *))
-{
- struct dentry *dentry;
- struct inode *inode;
- struct inode_operations *i_op;
-
- /* get dentry for @kobj->sd, dentry of a shadowed dir is pinned */
- dentry = sysfs_get_dentry(kobj->sd);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
-
- inode = dentry->d_inode;
- if (inode->i_op != &sysfs_dir_inode_operations) {
- dput(dentry);
- return -EINVAL;
- }
-
- i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
- if (!i_op)
- return -ENOMEM;
-
- memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
- i_op->follow_link = follow_link;
-
- /* Locking of inode->i_op?
- * Since setting i_op is a single word write and they
- * are atomic we should be ok here.
- */
- inode->i_op = i_op;
- return 0;
-}
-
-/**
- * sysfs_create_shadow_dir - create a shadow directory for an object.
- * @kobj: object we're creating directory for.
- *
- * sysfs_make_shadowed_dir must already have been called on this
- * directory.
- */
-
-struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj)
-{
- struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
- struct dentry *dir, *parent, *shadow;
- struct inode *inode;
- struct sysfs_dirent *sd;
- struct sysfs_addrm_cxt acxt;
-
- dir = sysfs_get_dentry(kobj->sd);
- if (IS_ERR(dir)) {
- sd = (void *)dir;
- goto out;
- }
- parent = dir->d_parent;
-
- inode = dir->d_inode;
- sd = ERR_PTR(-EINVAL);
- if (!sysfs_is_shadowed_inode(inode))
- goto out_dput;
-
- shadow = d_alloc(parent, &dir->d_name);
- if (!shadow)
- goto nomem;
-
- sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
- if (!sd)
- goto nomem;
- sd->s_elem.dir.kobj = kobj;
-
- sysfs_addrm_start(&acxt, parent_sd);
-
- /* add but don't link into children list */
- sysfs_add_one(&acxt, sd);
-
- /* attach and instantiate dentry */
- sysfs_attach_dentry(sd, shadow);
- d_instantiate(shadow, igrab(inode));
- inc_nlink(inode); /* tj: synchronization? */
-
- sysfs_addrm_finish(&acxt);
-
- dget(shadow); /* Extra count - pin the dentry in core */
-
- goto out_dput;
-
- nomem:
- dput(shadow);
- sd = ERR_PTR(-ENOMEM);
- out_dput:
- dput(dir);
- out:
- return sd;
-}
-
-/**
- * sysfs_remove_shadow_dir - remove an object's directory.
- * @shadow_sd: sysfs_dirent of shadow directory
- *
- * The only thing special about this is that we remove any files in
- * the directory before we remove the directory, and we've inlined
- * what used to be sysfs_rmdir() below, instead of calling separately.
- */
-
-void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd)
-{
- __sysfs_remove_dir(shadow_sd);
-}
-
const struct file_operations sysfs_dir_operations = {
.open = sysfs_dir_open,
.release = sysfs_dir_close,
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index e6b904d..d197237 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -13,7 +13,6 @@
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
-#include <linux/fs.h>
#include "sysfs.h"

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index aecb6e7..45128b7 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -33,16 +33,6 @@ static const struct inode_operations sysfs_inode_operations ={
.setattr = sysfs_setattr,
};

-void sysfs_delete_inode(struct inode *inode)
-{
- /* Free the shadowed directory inode operations */
- if (sysfs_is_shadowed_inode(inode)) {
- kfree(inode->i_op);
- inode->i_op = NULL;
- }
- return generic_delete_inode(inode);
-}
-
int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
struct inode * inode = dentry->d_inode;
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 69a73ae..119f39d 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -20,7 +20,7 @@ struct kmem_cache *sysfs_dir_cachep;

static const struct super_operations sysfs_ops = {
.statfs = simple_statfs,
- .drop_inode = sysfs_delete_inode,
+ .drop_inode = generic_delete_inode,
};

struct sysfs_dirent sysfs_root = {
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 6b8c8d7..b55e510 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -70,7 +70,6 @@ extern void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
struct sysfs_dirent *sd);
extern int sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);

-extern void sysfs_delete_inode(struct inode *inode);
extern struct inode * sysfs_get_inode(struct sysfs_dirent *sd);
extern void sysfs_instantiate(struct dentry *dentry, struct inode *inode);

@@ -121,8 +120,3 @@ static inline void sysfs_put(struct sysfs_dirent * sd)
if (sd && atomic_dec_and_test(&sd->s_count))
release_sysfs_dirent(sd);
}
-
-static inline int sysfs_is_shadowed_inode(struct inode *inode)
-{
- return S_ISDIR(inode->i_mode) && inode->i_op->follow_link;
-}
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 8b45946..56f5eaf 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -84,14 +84,9 @@ extern void kobject_init(struct kobject *);
extern void kobject_cleanup(struct kobject *);

extern int __must_check kobject_add(struct kobject *);
-extern int __must_check kobject_shadow_add(struct kobject *kobj,
- struct sysfs_dirent *shadow_parent);
extern void kobject_del(struct kobject *);

extern int __must_check kobject_rename(struct kobject *, const char *new_name);
-extern int __must_check kobject_shadow_rename(struct kobject *kobj,
- struct sysfs_dirent *new_parent,
- const char *new_name);
extern int __must_check kobject_move(struct kobject *, struct kobject *);

extern int __must_check kobject_register(struct kobject *);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index be8228e..c16e4c5 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -17,9 +17,6 @@

struct kobject;
struct module;
-struct nameidata;
-struct dentry;
-struct sysfs_dirent;

/* FIXME
* The *owner field is no longer used, but leave around
@@ -94,14 +91,13 @@ extern int sysfs_schedule_callback(struct kobject *kobj,
void (*func)(void *), void *data, struct module *owner);

extern int __must_check
-sysfs_create_dir(struct kobject *kobj, struct sysfs_dirent *shadow_parent_sd);
+sysfs_create_dir(struct kobject *);

extern void
sysfs_remove_dir(struct kobject *);

extern int __must_check
-sysfs_rename_dir(struct kobject *kobj, struct sysfs_dirent *new_parent_sd,
- const char *new_name);
+sysfs_rename_dir(struct kobject *kobj, const char *new_name);

extern int __must_check
sysfs_move_dir(struct kobject *, struct kobject *);
@@ -138,12 +134,6 @@ void sysfs_remove_file_from_group(struct kobject *kobj,

void sysfs_notify(struct kobject * k, char *dir, char *attr);

-
-extern int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *));
-extern struct sysfs_dirent *sysfs_create_shadow_dir(struct kobject *kobj);
-extern void sysfs_remove_shadow_dir(struct sysfs_dirent *shadow_sd);
-
extern int __must_check sysfs_init(void);

#else /* CONFIG_SYSFS */
@@ -154,8 +144,7 @@ static inline int sysfs_schedule_callback(struct kobject *kobj,
return -ENOSYS;
}

-static inline int sysfs_create_dir(struct kobject *kobj,
- struct sysfs_dirent *shadow_parent_sd)
+static inline int sysfs_create_dir(struct kobject * kobj)
{
return 0;
}
@@ -165,9 +154,7 @@ static inline void sysfs_remove_dir(struct kobject * k)
;
}

-static inline int sysfs_rename_dir(struct kobject *kobj,
- struct sysfs_dirent *new_parent_sd,
- const char *new_name)
+static inline int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
{
return 0;
}
@@ -242,12 +229,6 @@ static inline void sysfs_notify(struct kobject * k, char *dir, char *attr)
{
}

-static inline int sysfs_make_shadowed_dir(struct kobject *kobj,
- void * (*follow_link)(struct dentry *, struct nameidata *))
-{
- return 0;
-}
-
static inline int __must_check sysfs_init(void)
{
return 0;
diff --git a/lib/kobject.c b/lib/kobject.c
index 10ae2eb..e8181d3 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -44,11 +44,11 @@ static int populate_dir(struct kobject * kobj)
return error;
}

-static int create_dir(struct kobject *kobj, struct sysfs_dirent *shadow_parent)
+static int create_dir(struct kobject * kobj)
{
int error = 0;
if (kobject_name(kobj)) {
- error = sysfs_create_dir(kobj, shadow_parent);
+ error = sysfs_create_dir(kobj);
if (!error) {
if ((error = populate_dir(kobj)))
sysfs_remove_dir(kobj);
@@ -157,12 +157,11 @@ static void unlink(struct kobject * kobj)
}

/**
- * kobject_shadow_add - add an object to the hierarchy.
+ * kobject_add - add an object to the hierarchy.
* @kobj: object.
- * @shadow_parent: sysfs directory to add to.
*/

-int kobject_shadow_add(struct kobject *kobj, struct sysfs_dirent *shadow_parent)
+int kobject_add(struct kobject * kobj)
{
int error = 0;
struct kobject * parent;
@@ -194,7 +193,7 @@ int kobject_shadow_add(struct kobject *kobj, struct sysfs_dirent *shadow_parent)
kobj->parent = parent;
}

- error = create_dir(kobj, shadow_parent);
+ error = create_dir(kobj);
if (error) {
/* unlink does the kobject_put() for us */
unlink(kobj);
@@ -216,16 +215,6 @@ int kobject_shadow_add(struct kobject *kobj, struct sysfs_dirent *shadow_parent)
}

/**
- * kobject_add - add an object to the hierarchy.
- * @kobj: object.
- */
-int kobject_add(struct kobject * kobj)
-{
- return kobject_shadow_add(kobj, NULL);
-}
-
-
-/**
* kobject_register - initialize and add an object.
* @kobj: object in question.
*/
@@ -334,7 +323,7 @@ int kobject_rename(struct kobject * kobj, const char *new_name)
/* Note : if we want to send the new name alone, not the full path,
* we could probably use kobject_name(kobj); */

- error = sysfs_rename_dir(kobj, kobj->parent->sd, new_name);
+ error = sysfs_rename_dir(kobj, new_name);

/* This function is mostly/only used for network interface.
* Some hotplug package track interfaces by their name and
@@ -351,27 +340,6 @@ out:
}

/**
- * kobject_rename - change the name of an object
- * @kobj: object in question.
- * @new_parent: object's new parent
- * @new_name: object's new name
- */
-
-int kobject_shadow_rename(struct kobject *kobj,
- struct sysfs_dirent *new_parent, const char *new_name)
-{
- int error = 0;
-
- kobj = kobject_get(kobj);
- if (!kobj)
- return -EINVAL;
- error = sysfs_rename_dir(kobj, new_parent, new_name);
- kobject_put(kobj);
-
- return error;
-}
-
-/**
* kobject_move - move object to another parent
* @kobj: object in question.
* @new_parent: object's new parent (can be NULL)
--
1.5.3.4