NFSv4.1: allow zero fh array in filelayout decode layout

Signed-off-by: Andy Adamson <andros@netapp.com>
cc:stable@kernel.org [2.6.39]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 426908809c9738601f00cbf25fd220512f2141c1..5d6f369b15d0be564d0432cb1cffa3177cb80f9a 100644 (file)
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -552,13 +552,18 @@ filelayout_decode_layout(struct pnfs_layout_hdr *flo,
                __func__, nfl_util, fl->num_fh, fl->first_stripe_index,
                fl->pattern_offset);
 
-       if (!fl->num_fh)
+       /* Note that a zero value for num_fh is legal for STRIPE_SPARSE.
+        * Futher checking is done in filelayout_check_layout */
+       if (fl->num_fh < 0 || fl->num_fh >
+           max(NFS4_PNFS_MAX_STRIPE_CNT, NFS4_PNFS_MAX_MULTI_CNT))
                goto out_err;
 
-       fl->fh_array = kzalloc(fl->num_fh * sizeof(struct nfs_fh *),
-                              gfp_flags);
-       if (!fl->fh_array)
-               goto out_err;
+       if (fl->num_fh > 0) {
+               fl->fh_array = kzalloc(fl->num_fh * sizeof(struct nfs_fh *),
+                                      gfp_flags);
+               if (!fl->fh_array)
+                       goto out_err;
+       }
 
        for (i = 0; i < fl->num_fh; i++) {
                /* Do we want to use a mempool here? */