[1/4] Btrfs: fix a possible deadlock between scrub and transaction committing

Commit Message

Wang Shilong Feb. 19, 2014, 11:24 a.m. UTC

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 <[e-mail]>
---
 fs/btrfs/transaction.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

Patch

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 34cd831..84da666 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;