NFS: Fix a bug in nfs_fscache_release_page()

Not having an fscache cookie is perfectly valid if the user didn't mount
with the fscache option.

This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=15234

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: stable@kernel.org

1 files changed, 4 insertions, 5 deletions

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index fa588006588..237874f1af2 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -354,12 +354,11 @@ void nfs_fscache_reset_inode_cookie(struct inode *inode)
  */
 int nfs_fscache_release_page(struct page *page, gfp_t gfp)
 {
-        struct nfs_inode *nfsi = NFS_I(page->mapping->host);
-        struct fscache_cookie *cookie = nfsi->fscache;
-
-        BUG_ON(!cookie);
-
         if (PageFsCache(page)) {
+                struct nfs_inode *nfsi = NFS_I(page->mapping->host);
+                struct fscache_cookie *cookie = nfsi->fscache;
+
+                BUG_ON(!cookie);
                 dfprintk(FSCACHE, "NFS: fscache releasepage (0x%p/0x%p/0x%p)\n",
                          cookie, page, nfsi);