Btrfs: fix a possible deadlock between scrub and transaction committing

btrfs_scrub_continue() will be called when cleaning up transaction.However,
this can only be called if btrfs_scrub_pause() is called before.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

1 files changed, 11 insertions, 11 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 34cd83184c4a..84da6669f384 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1578,8 +1578,6 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans,
 
         trace_btrfs_transaction_commit(root);
 
-        btrfs_scrub_continue(root);
-
         if (current->journal_info == trans)
                 current->journal_info = NULL;
 
@@ -1754,7 +1752,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         /* ->aborted might be set after the previous check, so check it */
         if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
                 ret = cur_trans->aborted;
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
         /*
          * the reloc mutex makes sure that we stop
@@ -1771,7 +1769,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         ret = create_pending_snapshots(trans, root->fs_info);
         if (ret) {
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         /*
@@ -1787,13 +1785,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         ret = btrfs_run_delayed_items(trans, root);
         if (ret) {
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
         if (ret) {
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         /*
@@ -1823,7 +1821,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         if (ret) {
                 mutex_unlock(&root->fs_info->tree_log_mutex);
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         /*
@@ -1844,7 +1842,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         if (ret) {
                 mutex_unlock(&root->fs_info->tree_log_mutex);
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         /*
@@ -1855,7 +1853,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 ret = cur_trans->aborted;
                 mutex_unlock(&root->fs_info->tree_log_mutex);
                 mutex_unlock(&root->fs_info->reloc_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         btrfs_prepare_extent_commit(trans, root);
@@ -1891,13 +1889,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 btrfs_error(root->fs_info, ret,
                             "Error while writing out transaction");
                 mutex_unlock(&root->fs_info->tree_log_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         ret = write_ctree_super(trans, root, 0);
         if (ret) {
                 mutex_unlock(&root->fs_info->tree_log_mutex);
-                goto cleanup_transaction;
+                goto scrub_continue;
         }
 
         /*
@@ -1940,6 +1938,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
         return ret;
 
+scrub_continue:
+        btrfs_scrub_continue(root);
 cleanup_transaction:
         btrfs_trans_release_metadata(trans, root);
         trans->block_rsv = NULL;