[PATCH] VFS: BUG() if somebody tries to rehash an already hashed dentry

[Jan Blunck <jblunck@suse.de>]

Break early when somebody tries to rehash an already hashed dentry.
Otherwise this leads to interesting corruptions in the dcache hash table
later on.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Valerie Aurora (Henson) <vaurora@redhat.com>
---
 fs/dcache.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 75659a6..191c488 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1550,6 +1550,7 @@ void d_rehash(struct dentry * entry)
 {
 	spin_lock(&dcache_lock);
 	spin_lock(&entry->d_lock);
+	BUG_ON(!d_unhashed(entry));
 	_d_rehash(entry);
 	spin_unlock(&entry->d_lock);
 	spin_unlock(&dcache_lock);
-- 
1.6.0.2