On Wed, Mar 17, 2021 at 07:38:11PM +0900, Johannes Thumshirn wrote: > When a file gets deleted on a zoned file system, the space freed is no > 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%. > > 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. > > Signed-off-by: Johannes Thumshirn <johannes.thumsh...@wdc.com>
I'll add it as topic branch to for-next but I haven't reviewed it and first thing I see missing is lack of mentioning the sysfs tunable in the changelog.
