btrfs: clean snapshots one by one

[linux-2.6-block.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7505856df9f38cc53d9399b7b05da07417342b46..be09157ff91ba97a5728638fee5cd1a1ea3e4f95 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7286,6 +7286,8 @@ static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
  * reference count by one. if update_ref is true, this function
  * also make sure backrefs for the shared block and all lower level
  * blocks are properly updated.
+ *
+ * If called with for_reloc == 0, may exit early with -EAGAIN
  */
 int btrfs_drop_snapshot(struct btrfs_root *root,
                         struct btrfs_block_rsv *block_rsv, int update_ref,
@@ -7386,6 +7388,12 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
        wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
 
        while (1) {
+               if (!for_reloc && btrfs_fs_closing(root->fs_info)) {
+                       pr_debug("btrfs: drop snapshot early exit\n");
+                       err = -EAGAIN;
+                       goto out_end_trans;
+               }
+
                ret = walk_down_tree(trans, root, path, wc);
                if (ret < 0) {
                        err = ret;