[PATCH 1/2] fanotify: fix broken ref count in create_fd()

[Lino Sanfilippo]

In create_fd(), before we fallback to open a file read-only we should grab dentry
and mount refs again, since they have been put by the former failed call to dentry_open().

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
---
 fs/notify/fanotify/fanotify_user.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

 Please apply this against commit 26552d4aa4117cd3ea8cbe13ebf317da652e6bfd of
 branch 'origin/for-next' from git.infradead.org/users/eparis/notify.git

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 2d4925b..e108960 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -92,6 +92,10 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
 		 * in order to at least provide something to the listener.
 		 */
 		if (IS_ERR(new_file) && group->fanotify_data.readonly_fallback) {
+			/* dentry_open() put our refs, so get them again... */
+			dentry = dget(event->path.dentry);
+			mnt = mntget(event->path.mnt);
+
 			flags &= ~O_ACCMODE;
 			flags |= O_RDONLY;
 			new_file = dentry_open(dentry, mnt, flags,
-- 
1.5.6.5

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