1 files changed, 57 insertions, 17 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 50695dc5e2ab..b67171e6d688 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1269,6 +1269,8 @@ static int __update_reloc_root(struct btrfs_root *root, int del)
         }
         spin_unlock(&rc->reloc_root_tree.lock);
 
+        if (!node)
+                return 0;
         BUG_ON((struct btrfs_root *)node->data != root);
 
         if (!del) {
@@ -2238,13 +2240,28 @@ again:
 }
 
 static noinline_for_stack
+void free_reloc_roots(struct list_head *list)
+{
+        struct btrfs_root *reloc_root;
+
+        while (!list_empty(list)) {
+                reloc_root = list_entry(list->next, struct btrfs_root,
+                                        root_list);
+                __update_reloc_root(reloc_root, 1);
+                free_extent_buffer(reloc_root->node);
+                free_extent_buffer(reloc_root->commit_root);
+                kfree(reloc_root);
+        }
+}
+
+static noinline_for_stack
 int merge_reloc_roots(struct reloc_control *rc)
 {
         struct btrfs_root *root;
         struct btrfs_root *reloc_root;
         LIST_HEAD(reloc_roots);
         int found = 0;
-        int ret;
+        int ret = 0;
 again:
         root = rc->extent_root;
 
@@ -2270,20 +2287,33 @@ again:
                         BUG_ON(root->reloc_root != reloc_root);
 
                         ret = merge_reloc_root(rc, root);
-                        BUG_ON(ret);
+                        if (ret)
+                                goto out;
                 } else {
                         list_del_init(&reloc_root->root_list);
                 }
                 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
-                BUG_ON(ret < 0);
+                if (ret < 0) {
+                        if (list_empty(&reloc_root->root_list))
+                                list_add_tail(&reloc_root->root_list,
+                                              &reloc_roots);
+                        goto out;
+                }
         }
 
         if (found) {
                 found = 0;
                 goto again;
         }
+out:
+        if (ret) {
+                btrfs_std_error(root->fs_info, ret);
+                if (!list_empty(&reloc_roots))
+                        free_reloc_roots(&reloc_roots);
+        }
+
         BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
-        return 0;
+        return ret;
 }
 
 static void free_block_list(struct rb_root *blocks)
@@ -2818,8 +2848,10 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
         int err = 0;
 
         path = btrfs_alloc_path();
-        if (!path)
-                return -ENOMEM;
+        if (!path) {
+                err = -ENOMEM;
+                goto out_path;
+        }
 
         rb_node = rb_first(blocks);
         while (rb_node) {
@@ -2858,10 +2890,11 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
                 rb_node = rb_next(rb_node);
         }
 out:
-        free_block_list(blocks);
         err = finish_pending_nodes(trans, rc, path, err);
 
         btrfs_free_path(path);
+out_path:
+        free_block_list(blocks);
         return err;
 }
 
@@ -3698,7 +3731,15 @@ int prepare_to_relocate(struct reloc_control *rc)
         set_reloc_control(rc);
 
         trans = btrfs_join_transaction(rc->extent_root);
-        BUG_ON(IS_ERR(trans));
+        if (IS_ERR(trans)) {
+                unset_reloc_control(rc);
+                /*
+                 * extent tree is not a ref_cow tree and has no reloc_root to
+                 * cleanup.  And callers are responsible to free the above
+                 * block rsv.
+                 */
+                return PTR_ERR(trans);
+        }
         btrfs_commit_transaction(trans, rc->extent_root);
         return 0;
 }
@@ -3730,7 +3771,11 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
         while (1) {
                 progress++;
                 trans = btrfs_start_transaction(rc->extent_root, 0);
-                BUG_ON(IS_ERR(trans));
+                if (IS_ERR(trans)) {
+                        err = PTR_ERR(trans);
+                        trans = NULL;
+                        break;
+                }
 restart:
                 if (update_backref_cache(trans, &rc->backref_cache)) {
                         btrfs_end_transaction(trans, rc->extent_root);
@@ -4264,14 +4309,9 @@ int btrfs_recover_relocation(struct btrfs_root *root)
 out_free:
         kfree(rc);
 out:
-        while (!list_empty(&reloc_roots)) {
-                reloc_root = list_entry(reloc_roots.next,
-                                        struct btrfs_root, root_list);
-                list_del(&reloc_root->root_list);
-                free_extent_buffer(reloc_root->node);
-                free_extent_buffer(reloc_root->commit_root);
-                kfree(reloc_root);
-        }
+        if (!list_empty(&reloc_roots))
+                free_reloc_roots(&reloc_roots);
+
         btrfs_free_path(path);
 
         if (err == 0) {