Btrfs: make sure all dirty blocks are written at commit time

Write dirty block groups may allocate new block, and so may add new delayed
back ref. btrfs_run_delayed_refs may make some block groups dirty.

commit_cowonly_roots does not handle the recursion properly, and some dirty
blocks can be left unwritten at commit time. This patch moves
btrfs_run_delayed_refs into the loop that writes dirty block groups, and makes
the code not break out of the loop until there are no dirty block groups or
delayed back refs.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2dbf1c1f56ee..81f7124c3051 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -444,9 +444,6 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
 
         btrfs_write_dirty_block_groups(trans, root);
 
-        ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
-        BUG_ON(ret);
-
         while (1) {
                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
                 if (old_root_bytenr == root->node->start)
@@ -457,9 +454,8 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
                                         &root->root_key,
                                         &root->root_item);
                 BUG_ON(ret);
-                btrfs_write_dirty_block_groups(trans, root);
 
-                ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+                ret = btrfs_write_dirty_block_groups(trans, root);
                 BUG_ON(ret);
         }
         free_extent_buffer(root->commit_root);
@@ -495,9 +491,6 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
                 root = list_entry(next, struct btrfs_root, dirty_list);
 
                 update_cowonly_root(trans, root);
-
-                ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
-                BUG_ON(ret);
         }
         return 0;
 }