[PATCH 6.4 760/800] btrfs: reinsert BGs failed to reclaim

Greg Kroah-Hartman
2023-07-16T20:29:46Z

From: Naohiro Aota <naota@elisp.net>

commit 7e27180994383b7c741ad87749db01e4989a02ba upstream.

The reclaim process can temporarily fail. For example, if the space is
getting tight, it fails to make the block group read-only. If there are no
further writes on that block group, the block group will never get back to
the reclaim list, and the BG never gets reclaimed. In a certain workload,
we can leave many such block groups never reclaimed.

So, let's get it back to the list and give it a chance to be reclaimed.

Fixes: 18bb8bbf13c1 ("btrfs: zoned: automatically reclaim zones")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/block-group.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1837,6 +1837,8 @@ void btrfs_reclaim_bgs_work(struct work_
}

next:
+ if (ret)
+ btrfs_mark_bg_to_reclaim(bg);
btrfs_put_block_group(bg);

mutex_unlock(&fs_info->reclaim_bgs_lock);