[PATCH 5.8 129/186] btrfs: set the lockdep class for log tree extent buffers

From: Greg Kroah-Hartman
Date: Tue Sep 08 2020 - 15:15:28 EST

From: Josef Bacik <josef@xxxxxxxxxxxxxx>

commit d3beaa253fd6fa40b8b18a216398e6e5376a9d21 upstream.

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

CC: stable@xxxxxxxxxxxxxxx # 4.4+
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

fs/btrfs/ctree.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1297,6 +1297,8 @@ tree_mod_log_rewind(struct btrfs_fs_info

+ btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb_rewin),
+ eb_rewin, btrfs_header_level(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, u6

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, u6
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);