From 18bb8bbf13c1839b43c9e09e76d397b753989af2 Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Mon, 19 Apr 2021 16:41:02 +0900 Subject: btrfs: zoned: automatically reclaim zones When a file gets deleted on a zoned file system, the space freed is not returned back into the block group's free space, but is migrated to zone_unusable. As this zone_unusable space is behind the current write pointer it is not possible to use it for new allocations. In the current implementation a zone is reset once all of the block group's space is accounted as zone unusable. This behaviour can lead to premature ENOSPC errors on a busy file system. Instead of only reclaiming the zone once it is completely unusable, kick off a reclaim job once the amount of unusable bytes exceeds a user configurable threshold between 51% and 100%. It can be set per mounted filesystem via the sysfs tunable bg_reclaim_threshold which is set to 75% by default. Similar to reclaiming unused block groups, these dirty block groups are added to a to_reclaim list and then on a transaction commit, the reclaim process is triggered but after we deleted unused block groups, which will free space for the relocation process. Reviewed-by: Filipe Manana Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/block-group.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/btrfs/block-group.h') diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h index 3ecc3372a5ce..7b927425dc71 100644 --- a/fs/btrfs/block-group.h +++ b/fs/btrfs/block-group.h @@ -264,6 +264,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, u64 group_start, struct extent_map *em); void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info); void btrfs_mark_bg_unused(struct btrfs_block_group *bg); +void btrfs_reclaim_bgs_work(struct work_struct *work); +void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info); +void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg); int btrfs_read_block_groups(struct btrfs_fs_info *info); int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, u64 type, u64 chunk_offset, u64 size); -- cgit v1.2.3-73-gaa49b