* [PATCH v2 1/3] afs: Make /afs/.<cell> as well as /afs/<cell> mountpoints
2025-01-07 18:34 [PATCH v2 0/3] afs: Dynamic root improvements David Howells
@ 2025-01-07 18:34 ` David Howells
2025-01-07 18:34 ` [PATCH v2 2/3] afs: Add rootcell checks David Howells
2025-01-07 18:34 ` [PATCH v2 3/3] afs: Make /afs/@cell and /afs/.@cell symlinks David Howells
2 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2025-01-07 18:34 UTC (permalink / raw)
To: Marc Dionne
Cc: David Howells, Christian Brauner, linux-afs, linux-fsdevel,
linux-kernel
When a cell is instantiated, automatically create an /afs/.<cell>
mountpoint to match the /afs/<cell> mountpoint to match other AFS clients.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
fs/afs/cell.c | 13 +++++++-----
fs/afs/dynroot.c | 52 ++++++++++++++++++++++++++++++------------------
2 files changed, 41 insertions(+), 24 deletions(-)
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index caa09875f520..1aba6d4d03a9 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -146,18 +146,20 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
return ERR_PTR(-ENOMEM);
}
- cell->name = kmalloc(namelen + 1, GFP_KERNEL);
+ cell->name = kmalloc(1 + namelen + 1, GFP_KERNEL);
if (!cell->name) {
kfree(cell);
return ERR_PTR(-ENOMEM);
}
- cell->net = net;
+ cell->name[0] = '.';
+ cell->name++;
cell->name_len = namelen;
for (i = 0; i < namelen; i++)
cell->name[i] = tolower(name[i]);
cell->name[i] = 0;
+ cell->net = net;
refcount_set(&cell->ref, 1);
atomic_set(&cell->active, 0);
INIT_WORK(&cell->manager, afs_manage_cell_work);
@@ -211,7 +213,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
if (ret == -EINVAL)
printk(KERN_ERR "kAFS: bad VL server IP address\n");
error:
- kfree(cell->name);
+ kfree(cell->name - 1);
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
@@ -502,7 +504,7 @@ static void afs_cell_destroy(struct rcu_head *rcu)
afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
key_put(cell->anonymous_key);
- kfree(cell->name);
+ kfree(cell->name - 1);
kfree(cell);
afs_dec_cells_outstanding(net);
@@ -710,7 +712,8 @@ static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
afs_proc_cell_remove(cell);
mutex_lock(&net->proc_cells_lock);
- hlist_del_rcu(&cell->proc_link);
+ if (!hlist_unhashed(&cell->proc_link))
+ hlist_del_rcu(&cell->proc_link);
afs_dynroot_rmdir(net, cell);
mutex_unlock(&net->proc_cells_lock);
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index c4d2711e20ad..f80a4244b9d2 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -271,7 +271,8 @@ const struct dentry_operations afs_dynroot_dentry_operations = {
int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
{
struct super_block *sb = net->dynroot_sb;
- struct dentry *root, *subdir;
+ struct dentry *root, *subdir, *dsubdir;
+ char *dotname = cell->name - 1;
int ret;
if (!sb || atomic_read(&sb->s_active) == 0)
@@ -286,34 +287,31 @@ int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
goto unlock;
}
- /* Note that we're retaining an extra ref on the dentry */
+ dsubdir = lookup_one_len(dotname, root, cell->name_len + 1);
+ if (IS_ERR(dsubdir)) {
+ ret = PTR_ERR(dsubdir);
+ dput(subdir);
+ goto unlock;
+ }
+
+ /* Note that we're retaining extra refs on the dentries. */
subdir->d_fsdata = (void *)1UL;
+ dsubdir->d_fsdata = (void *)1UL;
ret = 0;
unlock:
inode_unlock(root->d_inode);
return ret;
}
-/*
- * Remove a manually added cell mount directory.
- * - The caller must hold net->proc_cells_lock
- */
-void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
+static void afs_dynroot_rm_one_dir(struct dentry *root, const char *name, size_t name_len)
{
- struct super_block *sb = net->dynroot_sb;
- struct dentry *root, *subdir;
-
- if (!sb || atomic_read(&sb->s_active) == 0)
- return;
-
- root = sb->s_root;
- inode_lock(root->d_inode);
+ struct dentry *subdir;
/* Don't want to trigger a lookup call, which will re-add the cell */
- subdir = try_lookup_one_len(cell->name, root, cell->name_len);
+ subdir = try_lookup_one_len(name, root, name_len);
if (IS_ERR_OR_NULL(subdir)) {
_debug("lookup %ld", PTR_ERR(subdir));
- goto no_dentry;
+ return;
}
_debug("rmdir %pd %u", subdir, d_count(subdir));
@@ -324,8 +322,24 @@ void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
dput(subdir);
}
dput(subdir);
-no_dentry:
- inode_unlock(root->d_inode);
+}
+
+/*
+ * Remove a manually added cell mount directory.
+ * - The caller must hold net->proc_cells_lock
+ */
+void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
+{
+ struct super_block *sb = net->dynroot_sb;
+ char *dotname = cell->name - 1;
+
+ if (!sb || atomic_read(&sb->s_active) == 0)
+ return;
+
+ inode_lock(sb->s_root->d_inode);
+ afs_dynroot_rm_one_dir(sb->s_root, cell->name, cell->name_len);
+ afs_dynroot_rm_one_dir(sb->s_root, dotname, cell->name_len + 1);
+ inode_unlock(sb->s_root->d_inode);
_leave("");
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 2/3] afs: Add rootcell checks
2025-01-07 18:34 [PATCH v2 0/3] afs: Dynamic root improvements David Howells
2025-01-07 18:34 ` [PATCH v2 1/3] afs: Make /afs/.<cell> as well as /afs/<cell> mountpoints David Howells
@ 2025-01-07 18:34 ` David Howells
2025-01-07 18:34 ` [PATCH v2 3/3] afs: Make /afs/@cell and /afs/.@cell symlinks David Howells
2 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2025-01-07 18:34 UTC (permalink / raw)
To: Marc Dionne
Cc: David Howells, Christian Brauner, linux-afs, linux-fsdevel,
linux-kernel
Add some checks for the validity of the cell name. It's may get put into a
symlink, so preclude it containing any slashes or "..". Also disallow
starting/ending with a dot. This makes /afs/@cell/ as a symlink less of a
security risk.
Also disallow multiple setting of /proc/net/afs/rootcell for any given
network namespace. Once set, the value may not be changed. This makes it
easier to only create /afs/@cell and /afs/.@cell if there's a rootcell.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
fs/afs/cell.c | 8 ++++++++
fs/afs/proc.c | 8 +++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 1aba6d4d03a9..cee42646736c 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -367,6 +367,14 @@ int afs_cell_init(struct afs_net *net, const char *rootcell)
len = cp - rootcell;
}
+ if (len == 0 || !rootcell[0] || rootcell[0] == '.' || rootcell[len - 1] == '.')
+ return -EINVAL;
+ if (memchr(rootcell, '/', len))
+ return -EINVAL;
+ cp = strstr(rootcell, "..");
+ if (cp && cp < rootcell + len)
+ return -EINVAL;
+
/* allocate a cell record for the root cell */
new_root = afs_lookup_cell(net, rootcell, len, vllist, false);
if (IS_ERR(new_root)) {
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 15eab053af6d..e7614f4f30c2 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -240,7 +240,13 @@ static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
/* determine command to perform */
_debug("rootcell=%s", buf);
- ret = afs_cell_init(net, buf);
+ ret = -EEXIST;
+ inode_lock(file_inode(file));
+ if (!net->ws_cell)
+ ret = afs_cell_init(net, buf);
+ else
+ printk("busy\n");
+ inode_unlock(file_inode(file));
out:
_leave(" = %d", ret);
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 3/3] afs: Make /afs/@cell and /afs/.@cell symlinks
2025-01-07 18:34 [PATCH v2 0/3] afs: Dynamic root improvements David Howells
2025-01-07 18:34 ` [PATCH v2 1/3] afs: Make /afs/.<cell> as well as /afs/<cell> mountpoints David Howells
2025-01-07 18:34 ` [PATCH v2 2/3] afs: Add rootcell checks David Howells
@ 2025-01-07 18:34 ` David Howells
2 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2025-01-07 18:34 UTC (permalink / raw)
To: Marc Dionne
Cc: David Howells, Christian Brauner, linux-afs, linux-fsdevel,
linux-kernel
Make /afs/@cell a symlink in the /afs dynamic root to match what other AFS
clients do rather than doing a substitution in the dentry name. This has
the bonus of being tab-expandable also.
Further, provide a /afs/.@cell symlink to point to the dotted cell share.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
Notes:
Changes
=======
ver #2)
- Directly create the symlink nodes rather than going through lookup.
fs/afs/dynroot.c | 177 +++++++++++++++++++++++++++----------
include/trace/events/afs.h | 2 +
2 files changed, 131 insertions(+), 48 deletions(-)
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index f80a4244b9d2..d8bf52f77d93 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -185,50 +185,6 @@ struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
return ret == -ENOENT ? NULL : ERR_PTR(ret);
}
-/*
- * Look up @cell in a dynroot directory. This is a substitution for the
- * local cell name for the net namespace.
- */
-static struct dentry *afs_lookup_atcell(struct dentry *dentry)
-{
- struct afs_cell *cell;
- struct afs_net *net = afs_d2net(dentry);
- struct dentry *ret;
- char *name;
- int len;
-
- if (!net->ws_cell)
- return ERR_PTR(-ENOENT);
-
- ret = ERR_PTR(-ENOMEM);
- name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
- if (!name)
- goto out_p;
-
- down_read(&net->cells_lock);
- cell = net->ws_cell;
- if (cell) {
- len = cell->name_len;
- memcpy(name, cell->name, len + 1);
- }
- up_read(&net->cells_lock);
-
- ret = ERR_PTR(-ENOENT);
- if (!cell)
- goto out_n;
-
- ret = lookup_one_len(name, dentry->d_parent, len);
-
- /* We don't want to d_add() the @cell dentry here as we don't want to
- * the cached dentry to hide changes to the local cell name.
- */
-
-out_n:
- kfree(name);
-out_p:
- return ret;
-}
-
/*
* Look up an entry in a dynroot directory.
*/
@@ -247,10 +203,6 @@ static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentr
return ERR_PTR(-ENAMETOOLONG);
}
- if (dentry->d_name.len == 5 &&
- memcmp(dentry->d_name.name, "@cell", 5) == 0)
- return afs_lookup_atcell(dentry);
-
return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
}
@@ -343,6 +295,131 @@ void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
_leave("");
}
+static void afs_atcell_delayed_put_cell(void *arg)
+{
+ struct afs_cell *cell = arg;
+
+ afs_put_cell(cell, afs_cell_trace_put_atcell);
+}
+
+/*
+ * Read @cell or .@cell symlinks.
+ */
+static const char *afs_atcell_get_link(struct dentry *dentry, struct inode *inode,
+ struct delayed_call *done)
+{
+ struct afs_vnode *vnode = AFS_FS_I(inode);
+ struct afs_cell *cell;
+ struct afs_net *net = afs_i2net(inode);
+ const char *name;
+ bool dotted = vnode->fid.vnode == 3;
+
+ if (!net->ws_cell)
+ return ERR_PTR(-ENOENT);
+
+ down_read(&net->cells_lock);
+
+ cell = net->ws_cell;
+ if (dotted)
+ name = cell->name - 1;
+ else
+ name = cell->name;
+ afs_get_cell(cell, afs_cell_trace_get_atcell);
+ set_delayed_call(done, afs_atcell_delayed_put_cell, cell);
+
+ up_read(&net->cells_lock);
+ return name;
+}
+
+static const struct inode_operations afs_atcell_inode_operations = {
+ .get_link = afs_atcell_get_link,
+};
+
+/*
+ * Look up @cell or .@cell in a dynroot directory. This is a substitution for
+ * the local cell name for the net namespace.
+ */
+static struct dentry *afs_dynroot_create_symlink(struct dentry *root, const char *name)
+{
+ struct afs_vnode *vnode;
+ struct afs_fid fid = { .vnode = 2, .unique = 1, };
+ struct dentry *dentry;
+ struct inode *inode;
+
+ if (name[0] == '.')
+ fid.vnode = 3;
+
+ dentry = d_alloc_name(root, name);
+ if (!dentry)
+ return ERR_PTR(-ENOMEM);
+
+ inode = iget5_locked(dentry->d_sb, fid.vnode,
+ afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
+ if (!inode) {
+ dput(dentry);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ vnode = AFS_FS_I(inode);
+
+ /* there shouldn't be an existing inode */
+ if (WARN_ON_ONCE(!(inode->i_state & I_NEW))) {
+ iput(inode);
+ dput(dentry);
+ return ERR_PTR(-EIO);
+ }
+
+ netfs_inode_init(&vnode->netfs, NULL, false);
+ simple_inode_init_ts(inode);
+ set_nlink(inode, 1);
+ inode->i_size = 0;
+ inode->i_mode = S_IFLNK | 0555;
+ inode->i_op = &afs_atcell_inode_operations;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
+ inode->i_blocks = 0;
+ inode->i_generation = 0;
+ inode->i_flags |= S_NOATIME;
+
+ unlock_new_inode(inode);
+ d_splice_alias(inode, dentry);
+ return dentry;
+}
+
+/*
+ * Create @cell and .@cell symlinks.
+ */
+static int afs_dynroot_symlink(struct afs_net *net)
+{
+ struct super_block *sb = net->dynroot_sb;
+ struct dentry *root, *symlink, *dsymlink;
+ int ret;
+
+ /* Let the ->lookup op do the creation */
+ root = sb->s_root;
+ inode_lock(root->d_inode);
+ symlink = afs_dynroot_create_symlink(root, "@cell");
+ if (IS_ERR(symlink)) {
+ ret = PTR_ERR(symlink);
+ goto unlock;
+ }
+
+ dsymlink = afs_dynroot_create_symlink(root, ".@cell");
+ if (IS_ERR(dsymlink)) {
+ ret = PTR_ERR(dsymlink);
+ dput(symlink);
+ goto unlock;
+ }
+
+ /* Note that we're retaining extra refs on the dentries. */
+ symlink->d_fsdata = (void *)1UL;
+ dsymlink->d_fsdata = (void *)1UL;
+ ret = 0;
+unlock:
+ inode_unlock(root->d_inode);
+ return ret;
+}
+
/*
* Populate a newly created dynamic root with cell names.
*/
@@ -355,6 +432,10 @@ int afs_dynroot_populate(struct super_block *sb)
mutex_lock(&net->proc_cells_lock);
net->dynroot_sb = sb;
+ ret = afs_dynroot_symlink(net);
+ if (ret < 0)
+ goto error;
+
hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
ret = afs_dynroot_mkdir(net, cell);
if (ret < 0)
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index a0aed1a428a1..de0e2301a037 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -168,12 +168,14 @@ enum yfs_cm_operation {
#define afs_cell_traces \
EM(afs_cell_trace_alloc, "ALLOC ") \
EM(afs_cell_trace_free, "FREE ") \
+ EM(afs_cell_trace_get_atcell, "GET atcell") \
EM(afs_cell_trace_get_queue_dns, "GET q-dns ") \
EM(afs_cell_trace_get_queue_manage, "GET q-mng ") \
EM(afs_cell_trace_get_queue_new, "GET q-new ") \
EM(afs_cell_trace_get_vol, "GET vol ") \
EM(afs_cell_trace_insert, "INSERT ") \
EM(afs_cell_trace_manage, "MANAGE ") \
+ EM(afs_cell_trace_put_atcell, "PUT atcell") \
EM(afs_cell_trace_put_candidate, "PUT candid") \
EM(afs_cell_trace_put_destroy, "PUT destry") \
EM(afs_cell_trace_put_queue_work, "PUT q-work") \
^ permalink raw reply related [flat|nested] 4+ messages in thread