btrfs: trace: Add trace points for unused block groups
This patch will add the following trace events:
1) btrfs_remove_block_group
For btrfs_remove_block_group() function.
Triggered when a block group is really removed.
2) btrfs_add_unused_block_group
Triggered which block group is added to unused_bgs list.
3) btrfs_skip_unused_block_group
Triggered which unused block group is not deleted.
These trace events is pretty handy to debug case related to block group
auto remove.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 295f829..888a478 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6358,6 +6358,7 @@ static int update_block_group(struct btrfs_trans_handle *trans,
spin_lock(&info->unused_bgs_lock);
if (list_empty(&cache->bg_list)) {
btrfs_get_block_group(cache);
+ trace_btrfs_add_unused_block_group(cache);
list_add_tail(&cache->bg_list,
&info->unused_bgs);
}
@@ -10192,6 +10193,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
/* Should always be true but just in case. */
if (list_empty(&cache->bg_list)) {
btrfs_get_block_group(cache);
+ trace_btrfs_add_unused_block_group(cache);
list_add_tail(&cache->bg_list,
&info->unused_bgs);
}
@@ -10379,6 +10381,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
BUG_ON(!block_group);
BUG_ON(!block_group->ro);
+ trace_btrfs_remove_block_group(block_group);
/*
* Free the reserved super bytes from this block group before
* remove it.
@@ -10743,6 +10746,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
* the ro check in case balance is currently acting on
* this block group.
*/
+ trace_btrfs_skip_unused_block_group(block_group);
spin_unlock(&block_group->lock);
up_write(&space_info->groups_sem);
goto next;