pnfs: check that partial LAYOUTGET return is ignored

Either a bad server reply, or our ignoring of multiple array segments in
a reply, can cause a reply to not meet our requirements.  Ensure
that we ignore such replies.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index c00b673261f9..cd9906415a14 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -660,6 +660,17 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         struct inode *ino = lo->plh_inode;
         int status = 0;
 
+        /* Verify we got what we asked for.
+         * Note that because the xdr parsing only accepts a single
+         * element array, this can fail even if the server is behaving
+         * correctly.
+         */
+        if (lgp->args.range.iomode > res->range.iomode ||
+            res->range.offset != 0 ||
+            res->range.length != NFS4_MAX_UINT64) {
+                status = -EINVAL;
+                goto out;
+        }
         /* Inject layout blob into I/O device driver */
         lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res);
         if (!lseg || IS_ERR(lseg)) {