[PATCH 3/8] btrfs: add space reservation tracepoint for reserved bytes

From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 3/8] btrfs: add space reservation tracepoint for reserved bytes
Date: Fri, 16 Aug 2019 10:19:47 -0400	[thread overview]
Message-ID: <20190816141952.19369-4-josef@toxicpanda.com> (raw)
In-Reply-To: <20190816141952.19369-1-josef@toxicpanda.com>

I noticed when folding the trace_btrfs_space_reservation() tracepoint
into the btrfs_space_info_update_* helpers that we didn't emit a
tracepoint when doing btrfs_add_reserved_bytes().  I know this is
because we were swapping bytes_may_use for bytes_reserved, so in my mind
there was no reason to have the tracepoint there.  But now there is
because we always emit the unreserve for the bytes_may_use side, and
this would have broken if compression was on anyway.  Add a tracepoint
to cover the bytes_reserved counter so the math still comes out right.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/block-group.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 9867c5d98650..afae5c731904 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2758,6 +2758,8 @@ int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
 	} else {
 		cache->reserved += num_bytes;
 		space_info->bytes_reserved += num_bytes;
+		trace_btrfs_space_reservation(cache->fs_info, "space_info",
+					      space_info->flags, num_bytes, 1);
 		btrfs_space_info_update_bytes_may_use(cache->fs_info,
 						      space_info, -ram_bytes);
 		if (delalloc)
-- 
2.21.0

