Btrfs: fix memory leak of log roots

When we abort a transaction while fsyncing, we'll skip freeing log roots
part of committing a transaction, which leads to memory leak.

This adds a 'free log roots' in putting super when no more users hold
references on log roots, so it's safe and clean.

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

2 files changed, 9 insertions, 2 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index eb7c1430852..5031e6dd593 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3253,6 +3253,11 @@ void btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
         if (btrfs_root_refs(&root->root_item) == 0)
                 synchronize_srcu(&fs_info->subvol_srcu);
 
+        if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                btrfs_free_log(NULL, root);
+                btrfs_free_log_root_tree(NULL, fs_info);
+        }
+
         __btrfs_remove_free_space_cache(root->free_ino_pinned);
         __btrfs_remove_free_space_cache(root->free_ino_ctl);
         free_fs_root(root);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index e8b7a68e1b3..8e85e0e4333 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2466,8 +2466,10 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
                 .process_func = process_one_buffer
         };
 
-        ret = walk_log_tree(trans, log, &wc);
-        BUG_ON(ret);
+        if (trans) {
+                ret = walk_log_tree(trans, log, &wc);
+                BUG_ON(ret);
+        }
 
         while (1) {
                 ret = find_first_extent_bit(&log->dirty_log_pages,