Btrfs: don't bother kicking async if there's nothing to reclaim

We do this check when we start the async reclaimer thread, might as well check
before we kick it off to save us some cycles.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
(cherry picked from commit d38b349c39a9feb1aca82c3280b9b1234497d582)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 381ad6943b290fc08b963d440a87548b69d9b1e7..fa5dccb83a39ae5dcfd0235613a413b6abf70344 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4870,6 +4870,9 @@ static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
        if (space_info->bytes_used >= thresh)
                return 0;
 
+       if (!btrfs_calc_reclaim_metadata_size(fs_info->fs_root, space_info))
+               return 0;
+
        return (used >= thresh && !btrfs_fs_closing(fs_info) &&
                !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
 }