nfs: Check whether a layout pointer is NULL before free it

The new layout pointer in pnfs_find_alloc_layout() may be NULL because of
out of memory. we must do some check work, otherwise pnfs_free_layout_hdr()
will go wrong because it can not deal with a NULL pointer.

Signed-off-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index fe624c9..2878f97 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -925,8 +925,8 @@ pnfs_find_alloc_layout(struct inode *ino,
        if (likely(nfsi->layout == NULL)) {     /* Won the race? */
                nfsi->layout = new;
                return new;
-       }
-       pnfs_free_layout_hdr(new);
+       } else if (new != NULL)
+               pnfs_free_layout_hdr(new);
 out_existing:
        pnfs_get_layout_hdr(nfsi->layout);
        return nfsi->layout;