diff options
| author | NeilBrown <neilb@suse.de> | 2024-06-17 18:23:01 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-06-18 16:26:09 +0200 |
| commit | 7d1cf5e624ef5d81b933e8b7f4927531166c0f7a (patch) | |
| tree | 7c1fae3907611fc335fbbd5234b5d6dcd62a4c57 /fs/namei.c | |
| parent | 702eb71fd6501b3566283f8c96d7ccc6ddd662e9 (diff) | |
vfs: generate FS_CREATE before FS_OPEN when ->atomic_open used.
When a file is opened and created with open(..., O_CREAT) we get
both the CREATE and OPEN fsnotify events and would expect them in that
order. For most filesystems we get them in that order because
open_last_lookups() calls fsnofify_create() and then do_open() (from
path_openat()) calls vfs_open()->do_dentry_open() which calls
fsnotify_open().
However when ->atomic_open is used, the
do_dentry_open() -> fsnotify_open()
call happens from finish_open() which is called from the ->atomic_open
handler in lookup_open() which is called *before* open_last_lookups()
calls fsnotify_create. So we get the "open" notification before
"create" - which is backwards. ltp testcase inotify02 tests this and
reports the inconsistency.
This patch lifts the fsnotify_open() call out of do_dentry_open() and
places it higher up the call stack. There are three callers of
do_dentry_open().
For vfs_open() and kernel_file_open() the fsnotify_open() is placed
directly in that caller so there should be no behavioural change.
For finish_open() there are two cases:
- finish_open is used in ->atomic_open handlers. For these we add a
call to fsnotify_open() at open_last_lookups() if FMODE_OPENED is
set - which means do_dentry_open() has been called.
- finish_open is used in ->tmpfile() handlers. For these a similar
call to fsnotify_open() is added to vfs_tmpfile()
With this patch NFSv3 is restored to its previous behaviour (before
->atomic_open support was added) of generating CREATE notifications
before OPEN, and NFSv4 now has that same correct ordering that is has
not had before. I haven't tested other filesystems.
Fixes: 7c6c5249f061 ("NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.")
Reported-by: James Clark <james.clark@arm.com>
Closes: https://lore.kernel.org/all/01c3bf2e-eb1f-4b7f-a54f-d2a05dd3d8c8@arm.com
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/171817619547.14261.975798725161704336@noble.neil.brown.name
Fixes: 7b8c9d7bb457 ("fsnotify: move fsnotify_open() hook into do_dentry_open()")
Tested-by: James Clark <james.clark@arm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240617162303.1596-2-jack@suse.cz
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c index 37fb0a8aa09a..1e05a0f3f04d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3572,8 +3572,12 @@ static const char *open_last_lookups(struct nameidata *nd, else inode_lock_shared(dir->d_inode); dentry = lookup_open(nd, file, op, got_write); - if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED)) - fsnotify_create(dir->d_inode, dentry); + if (!IS_ERR(dentry)) { + if (file->f_mode & FMODE_CREATED) + fsnotify_create(dir->d_inode, dentry); + if (file->f_mode & FMODE_OPENED) + fsnotify_open(file); + } if (open_flag & O_CREAT) inode_unlock(dir->d_inode); else @@ -3700,6 +3704,8 @@ int vfs_tmpfile(struct mnt_idmap *idmap, mode = vfs_prepare_mode(idmap, dir, mode, mode, mode); error = dir->i_op->tmpfile(idmap, dir, file, mode); dput(child); + if (file->f_mode & FMODE_OPENED) + fsnotify_open(file); if (error) return error; /* Don't check for other permissions, the inode was just created */ |