Btrfs: fix EIO from btrfs send in is_extent_unchanged for punched holes

When you take a snapshot, punch a hole where there has been data, then take
another snapshot and try to send an incremental stream, btrfs send would
give you EIO. That is because is_extent_unchanged had no support for holes
being punched. With this patch, instead of returning EIO we just return
0 (== the extent is not unchanged) and we're good.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Cc: Alexander Block <ablock84@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 68da757615ae..ed897dc11356 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -3945,12 +3945,10 @@ static int is_extent_unchanged(struct send_ctx *sctx,
                     found_key.type != key.type) {
                         key.offset += right_len;
                         break;
-                } else {
-                        if (found_key.offset != key.offset + right_len) {
-                                /* Should really not happen */
-                                ret = -EIO;
-                                goto out;
-                        }
+                }
+                if (found_key.offset != key.offset + right_len) {
+                        ret = 0;
+                        goto out;
                 }
                 key = found_key;
         }