From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 4 Jul 2018 12:59:58 +0300
Subject: [PATCH] pnfs/blocklayout: off by one in bl_map_stripe()
Git-commit: 0914bb965e38a055e9245637aed117efbe976e91
Patch-mainline: v4.19-rc1
References: git-fixes

"dev->nr_children" is the number of children which were parsed
successfully in bl_parse_stripe().  It could be all of them and then, in
that case, it is equal to v->stripe.volumes_count.  Either way, the >
should be >= so that we don't go beyond the end of what we're supposed
to.

Fixes: 5c83746a0cf2 ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/blocklayout/dev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -203,7 +203,7 @@ static bool bl_map_stripe(struct pnfs_bl
 	chunk = div_u64(offset, dev->chunk_size);
 	div_u64_rem(chunk, dev->nr_children, &chunk_idx);
 
-	if (chunk_idx > dev->nr_children) {
+	if (chunk_idx >= dev->nr_children) {
 		dprintk("%s: invalid chunk idx %d (%lld/%lld)\n",
 			__func__, chunk_idx, offset, dev->chunk_size);
 		/* error, should not happen */