Btrfs: fix tree mod log rewind of ADD operations

When a MOD_LOG_KEY_ADD operation is rewinded, we remove the key from the
tree block. If its not the last key, removal involves a move operation.
This move operation was explicitly done before this commit.

However, at insertion time, there's a move operation before the actual
addition to make room for the new key, which is recorded in the tree mod
log as well. This means, we must drop the move operation when rewinding the
add operation, because the next operation we'll be rewinding will be the
corresponding MOD_LOG_MOVE_KEYS operation.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e005d9b046169c6a2b396c6662b929d62c8b8749..b98f8604f4f6e8029edf20ca78ab0ce31c30c1ea 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1094,11 +1094,7 @@ __tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq,
                                                      tm->generation);
                        break;
                case MOD_LOG_KEY_ADD:
-                       if (tm->slot != n - 1) {
-                               o_dst = btrfs_node_key_ptr_offset(tm->slot);
-                               o_src = btrfs_node_key_ptr_offset(tm->slot + 1);
-                               memmove_extent_buffer(eb, o_dst, o_src, p_size);
-                       }
+                       /* if a move operation is needed it's in the log */
                        n--;
                        break;
                case MOD_LOG_MOVE_KEYS: