1 files changed, 19 insertions, 13 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 63f59f17c97e..4320f346b0b9 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2809,6 +2809,12 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	log->log_transid = root->log_transid;
 	root->log_start_pid = 0;
 	/*
+	 * Update or create log root item under the root's log_mutex to prevent
+	 * races with concurrent log syncs that can lead to failure to update
+	 * log root item because it was not created yet.
+	 */
+	ret = update_log_root(trans, log);
+	/*
 	 * IO has been started, blocks of the log tree have WRITTEN flag set
 	 * in their headers. new modifications of the log will be written to
 	 * new positions. so it's safe to allow log writers to go in.
@@ -2827,8 +2833,6 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 
 	mutex_unlock(&log_root_tree->log_mutex);
 
-	ret = update_log_root(trans, log);
-
 	mutex_lock(&log_root_tree->log_mutex);
 	if (atomic_dec_and_test(&log_root_tree->log_writers)) {
 		/*
@@ -3321,9 +3325,16 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
 	}
 	btrfs_release_path(path);
 
-	/* find the first key from this transaction again */
+	/*
+	 * Find the first key from this transaction again.  See the note for
+	 * log_new_dir_dentries, if we're logging a directory recursively we
+	 * won't be holding its i_mutex, which means we can modify the directory
+	 * while we're logging it.  If we remove an entry between our first
+	 * search and this search we'll not find the key again and can just
+	 * bail.
+	 */
 	ret = btrfs_search_slot(NULL, root, &min_key, path, 0, 0);
-	if (WARN_ON(ret != 0))
+	if (ret != 0)
 		goto done;
 
 	/*
@@ -4393,13 +4404,8 @@ static int btrfs_log_trailing_hole(struct btrfs_trans_handle *trans,
 					struct btrfs_file_extent_item);
 
 		if (btrfs_file_extent_type(leaf, extent) ==
-		    BTRFS_FILE_EXTENT_INLINE) {
-			len = btrfs_file_extent_inline_len(leaf,
-							   path->slots[0],
-							   extent);
-			ASSERT(len == i_size);
+		    BTRFS_FILE_EXTENT_INLINE)
 			return 0;
-		}
 
 		len = btrfs_file_extent_num_bytes(leaf, extent);
 		/* Last extent goes beyond i_size, no need to log a hole. */
@@ -5122,7 +5128,7 @@ process_leaf:
 			}
 
 			if (btrfs_inode_in_log(di_inode, trans->transid)) {
-				iput(di_inode);
+				btrfs_add_delayed_iput(di_inode);
 				continue;
 			}
 
@@ -5132,7 +5138,7 @@ process_leaf:
 			btrfs_release_path(path);
 			ret = btrfs_log_inode(trans, root, di_inode,
 					      log_mode, 0, LLONG_MAX, ctx);
-			iput(di_inode);
+			btrfs_add_delayed_iput(di_inode);
 			if (ret)
 				goto next_dir_inode;
 			if (ctx->log_new_dentries) {
@@ -5270,7 +5276,7 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
 
 			ret = btrfs_log_inode(trans, root, dir_inode,
 					      LOG_INODE_ALL, 0, LLONG_MAX, ctx);
-			iput(dir_inode);
+			btrfs_add_delayed_iput(dir_inode);
 			if (ret)
 				goto out;
 		}