NFSv4/pnfs: Ensure pnfs_parse_lgopen() won't try to parse uninitialised data

We need to ensure that pnfs_parse_lgopen() doesn't try to parse a
struct nfs4_layoutget_res that was not filled by a successful call
to decode_layoutget(). This can happen if we performed a cached open,
or if either the OP_ACCESS or OP_GETATTR operations preceding the
OP_LAYOUTGET in the compound returned an error.

By initialising the 'status' field to NFS4ERR_DELAY, we ensure that
pnfs_parse_lgopen() won't try to interpret the structure.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b0e42fd..4d3f04d 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -994,7 +994,8 @@ pnfs_alloc_init_layoutget_args(struct inode *ino,
        lgp->args.layout.pglen = max_pages * PAGE_SIZE;
        lgp->res.layoutp = &lgp->args.layout;
 
-
+       /* Don't confuse uninitialised result and success */
+       lgp->res.status = -NFS4ERR_DELAY;
 
        lgp->args.minlength = PAGE_SIZE;
        if (lgp->args.minlength > range->length)