Btrfs: do not BUG_ON on aborted situation

Btrfs balance can easily hit BUG_ON in these places, but we want
to it bail out gracefully after we force the whole filesystem to
readonly.  So we use btrfs_std_error hook in place of BUG_ON.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

2 files changed, 12 insertions, 3 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 9d13786eec73..3ebe87977aae 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3771,7 +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);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 35bb2d4ed29f..9ff454df6756 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2379,7 +2379,11 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
                 return ret;
 
         trans = btrfs_start_transaction(root, 0);
-        BUG_ON(IS_ERR(trans));
+        if (IS_ERR(trans)) {
+                ret = PTR_ERR(trans);
+                btrfs_std_error(root->fs_info, ret);
+                return ret;
+        }
 
         lock_chunks(root);
 
@@ -3050,7 +3054,8 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
 
         unset_balance_control(fs_info);
         ret = del_balance_item(fs_info->tree_root);
-        BUG_ON(ret);
+        if (ret)
+                btrfs_std_error(fs_info, ret);
 
         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
 }