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fsnotify: clarify contract for create event hooks

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[ Upstream commit dabe729dddca550446e9cc118c96d1f91703345b ]

Clarify argument names and contract for fsnotify_create() and
fsnotify_mkdir() to reflect the anomaly of kernfs, which leaves dentries
negavite after mkdir/create.

Remove the WARN_ON(!inode) in audit code that were added by the Fixes
commit under the wrong assumption that dentries cannot be negative after
mkdir/create.

Fixes: aa93bdc5500c ("fsnotify: use helpers to access data by data_type")
Link: https://lore.kernel.org/linux-fsdevel/87mtp5yz0q.fsf@collabora.com/
Link: https://lore.kernel.org/r/20211025192746.66445-4-krisman@collabora.com
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Amir Goldstein 2021-10-25 16:27:18 -03:00 committed by Ksawlii
parent c996590673
commit a4abea3ffa
3 changed files with 18 additions and 10 deletions
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22
include/linux/fsnotify.h
View file

@ -192,16 +192,22 @@ static inline void fsnotify_inoderemove(struct inode *inode)
/* /*
* fsnotify_create - 'name' was linked in * fsnotify_create - 'name' was linked in
*
* Caller must make sure that dentry->d_name is stable.
* Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
* ->d_inode later
*/ */
static inline void fsnotify_create(struct inode *inode, struct dentry *dentry) static inline void fsnotify_create(struct inode *dir, struct dentry *dentry)
{ {
audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE); audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
fsnotify_dirent(inode, dentry, FS_CREATE); fsnotify_dirent(dir, dentry, FS_CREATE);
} }
/* /*
* fsnotify_link - new hardlink in 'inode' directory * fsnotify_link - new hardlink in 'inode' directory
*
* Caller must make sure that new_dentry->d_name is stable.
* Note: We have to pass also the linked inode ptr as some filesystems leave * Note: We have to pass also the linked inode ptr as some filesystems leave
* new_dentry->d_inode NULL and instantiate inode pointer later * new_dentry->d_inode NULL and instantiate inode pointer later
*/ */
@ -267,12 +273,16 @@ static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
/* /*
* fsnotify_mkdir - directory 'name' was created * fsnotify_mkdir - directory 'name' was created
*
* Caller must make sure that dentry->d_name is stable.
* Note: some filesystems (e.g. kernfs) leave @dentry negative and instantiate
* ->d_inode later
*/ */
static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry) static inline void fsnotify_mkdir(struct inode *dir, struct dentry *dentry)
{ {
audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE); audit_inode_child(dir, dentry, AUDIT_TYPE_CHILD_CREATE);
fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR); fsnotify_dirent(dir, dentry, FS_CREATE | FS_ISDIR);
} }
/* /*

3
kernel/audit_fsnotify.c
View file

@ -161,8 +161,7 @@ static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark); audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark);
if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group) || if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group))
WARN_ON_ONCE(!inode))
return 0; return 0;
if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) { if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) {

3
kernel/audit_watch.c
View file

@ -472,8 +472,7 @@ static int audit_watch_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
parent = container_of(inode_mark, struct audit_parent, mark); parent = container_of(inode_mark, struct audit_parent, mark);
if (WARN_ON_ONCE(inode_mark->group != audit_watch_group) || if (WARN_ON_ONCE(inode_mark->group != audit_watch_group))
WARN_ON_ONCE(!inode))
return 0; return 0;
if (mask & (FS_CREATE|FS_MOVED_TO) && inode) if (mask & (FS_CREATE|FS_MOVED_TO) && inode)