[PATCH] cachefiles: Fix excess dput() after end_removing()

[David Howells]

When cachefiles_cull() calls cachefiles_bury_object(), the latter eats the
former's ref on the victim dentry that it obtained from
cachefiles_lookup_for_cull().  However, commit 7bb1eb45e43c left the dput
of the victim in place, resulting in occasional:

  WARNING: fs/dcache.c:829 at dput.part.0+0xf5/0x110, CPU#7: cachefilesd/11831
  cachefiles_cull+0x8c/0xe0 [cachefiles]
  cachefiles_daemon_cull+0xcd/0x120 [cachefiles]
  cachefiles_daemon_write+0x14e/0x1d0 [cachefiles]
  vfs_write+0xc3/0x480
  ...

reports.

Fix this by removing the dput().

Fixes: 7bb1eb45e43c ("VFS: introduce start_removing_dentry()")
Reported-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: NeilBrown <neil@xxxxxxxxxx>
cc: Paulo Alcantara <pc@xxxxxxxxxxxxx>
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
 fs/cachefiles/namei.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index bdac2f33edf3..e2023e78e4df 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -795,7 +795,6 @@ int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 
 	ret = cachefiles_bury_object(cache, NULL, dir, victim,
 				     FSCACHE_OBJECT_WAS_CULLED);
-	dput(victim);
 	if (ret < 0)
 		goto error;