[PATCH] fscache: Fix error handling in fscache_begin_operation()

[David Howells <dhowells@xxxxxxxxxx>]

Fix fscache_begin_operation() to clear cres->cache_priv on error, otherwise
fscache_resources_valid() will report it as being valid.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Reported-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
 fs/netfs/fscache_io.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/netfs/fscache_io.c b/fs/netfs/fscache_io.c
index ad57e4412c6d..cfd58ad95e7c 100644
--- a/fs/netfs/fscache_io.c
+++ b/fs/netfs/fscache_io.c
@@ -83,8 +83,10 @@ static int fscache_begin_operation(struct netfs_cache_resources *cres,
 	cres->debug_id		= cookie->debug_id;
 	cres->inval_counter	= cookie->inval_counter;
 
-	if (!fscache_begin_cookie_access(cookie, why))
+	if (!fscache_begin_cookie_access(cookie, why)) {
+		cres->cache_priv = NULL;
 		return -ENOBUFS;
+	}
 
 again:
 	spin_lock(&cookie->lock);