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>
This commit is contained in:
Qu Wenruo 2018-04-26 17:17:20 +08:00 committed by David Sterba
parent 3dca5c942d
commit 4ed0a7a3b7
3 changed files with 47 additions and 0 deletions

View File

@ -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;

View File

@ -3984,6 +3984,7 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
spin_lock(&fs_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,
&fs_info->unused_bgs);
}

View File

@ -1805,6 +1805,48 @@ TRACE_EVENT(btrfs_inode_mod_outstanding_extents,
__entry->ino, __entry->mod)
);
DECLARE_EVENT_CLASS(btrfs__block_group,
TP_PROTO(const struct btrfs_block_group_cache *bg_cache),
TP_ARGS(bg_cache),
TP_STRUCT__entry_btrfs(
__field( u64, bytenr )
__field( u64, len )
__field( u64, used )
__field( u64, flags )
),
TP_fast_assign_btrfs(bg_cache->fs_info,
__entry->bytenr = bg_cache->key.objectid,
__entry->len = bg_cache->key.offset,
__entry->used = btrfs_block_group_used(&bg_cache->item);
__entry->flags = bg_cache->flags;
),
TP_printk_btrfs("bg bytenr=%llu len=%llu used=%llu flags=%llu(%s)",
__entry->bytenr, __entry->len, __entry->used, __entry->flags,
__print_flags(__entry->flags, "|", BTRFS_GROUP_FLAGS))
);
DEFINE_EVENT(btrfs__block_group, btrfs_remove_block_group,
TP_PROTO(const struct btrfs_block_group_cache *bg_cache),
TP_ARGS(bg_cache)
);
DEFINE_EVENT(btrfs__block_group, btrfs_add_unused_block_group,
TP_PROTO(const struct btrfs_block_group_cache *bg_cache),
TP_ARGS(bg_cache)
);
DEFINE_EVENT(btrfs__block_group, btrfs_skip_unused_block_group,
TP_PROTO(const struct btrfs_block_group_cache *bg_cache),
TP_ARGS(bg_cache)
);
#endif /* _TRACE_BTRFS_H */
/* This part must be outside protection */