Re: [PATCH 0/5] btrfs: some fixes around unused block deletion

[Filipe Manana <fdmanana@kernel.org>]

On Sat, Jan 27, 2024 at 9:39 PM Ivan Shapovalov <intelfx@intelfx.name> wrote:
>
> On 2024-01-25 at 10:26 +0000, fdmanana@kernel.org wrote:
> > From: Filipe Manana <fdmanana@suse.com>
> >
> > These fix a couple issues regarding block group deletion, either
> > deleting
> > an unused block group when it shouldn't be deleted due to outstanding
> > reservations relying on the block group, or unused block groups never
> > getting deleted since they were created due to pessimistic space
> > reservation and ended up never being used. More details on the change
> > logs of each patch.
> >
> > Filipe Manana (5):
> >   btrfs: add and use helper to check if block group is used
> >   btrfs: do not delete unused block group if it may be used soon
> >   btrfs: add new unused block groups to the list of unused block
> > groups
> >   btrfs: document what the spinlock unused_bgs_lock protects
> >   btrfs: add comment about list_is_singular() use at
> > btrfs_delete_unused_bgs()
> >
> >  fs/btrfs/block-group.c | 87
> > +++++++++++++++++++++++++++++++++++++++++-
> >  fs/btrfs/block-group.h |  7 ++++
> >  fs/btrfs/fs.h          |  3 ++
> >  3 files changed, 95 insertions(+), 2 deletions(-)
> >
>
> Still broken for me, unfortunately.

I'm curious about your workload. Is it something like continuous,
non-stop deduplication or cloning for example?

Did you actually experience -ENOSPC errors?

Also, if you unmount and then mount again the fs, any unused block
groups should be scheduled for deletion once the cleaner thread runs,
at least if there's not a huge workload for a minute or two.

On top of this patchset, can you try the following patch?

https://pastebin.com/raw/U7b0e03g

If that still doesn't help, try the following the following patch on
top of this patchset:

https://pastebin.com/raw/rKiSmG5w

Thanks.

>
> --
> Ivan Shapovalov / intelfx /