This is a note to let you know that I've just added the patch titled
fanotify: Allow file handle encoding for unhashed events
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fanotify-allow-file-handle-encoding-for-unhashed-eve.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6b954c9e191f65c843a9c4cdd32bfba9ab435e43
Author: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Date: Mon Oct 25 16:27:29 2021 -0300
fanotify: Allow file handle encoding for unhashed events
[ Upstream commit 74fe4734897a2da2ae2a665a5e622cd490d36eaf ]
Allow passing a NULL hash to fanotify_encode_fh and avoid calculating
the hash if not needed.
Link: https://lore.kernel.org/r/20211025192746.66445-15-krisman@xxxxxxxxxxxxx
Reviewed-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 397ee623ff1e8..ec84fee7ad01c 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -403,8 +403,12 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
fh->type = type;
fh->len = fh_len;
- /* Mix fh into event merge key */
- *hash ^= fanotify_hash_fh(fh);
+ /*
+ * Mix fh into event merge key. Hash might be NULL in case of
+ * unhashed FID events (i.e. FAN_FS_ERROR).
+ */
+ if (hash)
+ *hash ^= fanotify_hash_fh(fh);
return FANOTIFY_FH_HDR_LEN + fh_len;
