Commit 9cc0b837 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: don't block if we can't acquire the reclaim lock 



If we can't acquire the reclaim_bgs_lock on block group reclaim, we
block until it is free. This can potentially stall for a long time.

While reclaim of block groups is necessary for a good user experience on
a zoned file system, there still is no need to block as it is best
effort only, just like when we're deleting unused block groups.

CC: stable@vger.kernel.org # 5.13
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent abb99cfd

fs/btrfs/block-group.c

+9 −1
Original line number Diff line number Diff line
@@ -1498,7 +1498,15 @@ void btrfs_reclaim_bgs_work(struct work_struct *work) 
	if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))

		return;



	mutex_lock(&fs_info->reclaim_bgs_lock);

	/*

	 * Long running balances can keep us blocked here for eternity, so

	 * simply skip reclaim if we're unable to get the mutex.

	 */

	if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {

		btrfs_exclop_finish(fs_info);

		return;

	}



	spin_lock(&fs_info->unused_bgs_lock);

	while (!list_empty(&fs_info->reclaim_bgs)) {

		u64 zone_unusable;