btrfs: set the lockdep class for log tree extent buffers

These are special extent buffers that get rewound in order to lookup
the state of the tree at a specific point in time.  As such they do not
go through the normal initialization paths that set their lockdep class,
so handle them appropriately when they are created and before they are
locked.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index cd1cd673bc0bf3d6d27e485f0953fd00bf01e5e6..cd392da69b8190a69071e041e7802452fa7588f4 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1297,6 +1297,8 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
        btrfs_tree_read_unlock_blocking(eb);
        free_extent_buffer(eb);
 
+       btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb_rewin),
+                                      eb_rewin, btrfs_header_level(eb_rewin));
        btrfs_tree_read_lock(eb_rewin);
        __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
        WARN_ON(btrfs_header_nritems(eb_rewin) >
@@ -1370,7 +1372,6 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
 
        if (!eb)
                return NULL;
-       btrfs_tree_read_lock(eb);
        if (old_root) {
                btrfs_set_header_bytenr(eb, eb->start);
                btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
@@ -1378,6 +1379,9 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
                btrfs_set_header_level(eb, old_root->level);
                btrfs_set_header_generation(eb, old_generation);
        }
+       btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb), eb,
+                                      btrfs_header_level(eb));
+       btrfs_tree_read_lock(eb);
        if (tm)
                __tree_mod_log_rewind(fs_info, eb, time_seq, tm);
        else