[PATCH] btrfs: zoned: fix incorrect ASSERT in btrfs_zoned_reserve_data_reloc_bg

[PATCH] btrfs: zoned: fix incorrect ASSERT in btrfs_zoned_reserve_data_reloc_bg

[Johannes Thumshirn]

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

When moving a block-group to the dedicated data relocation space-info in
btrfs_zoned_reserve_data_reloc_bg() it is ASSERT()ed that the newly
created block-group for data relocation does not contain any zone_unusable
bytes.

But on disks with zone_capacity < zone_size, the difference between
zone_size and zone_capacity is accounted as zone_unusable.

Instead of ASSERT()ing that the block-group does not contain any
zone_unusable bytes, remove them from the block-groups total size.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Link: https://lore.kernel.org/linux-block/CAHj4cs8-cS2E+-xQ-d2Bj6vMJZ+CwT_cbdWBTju4BV35LsvEYw@mail.gmail.com/
Fixes: daa0fde322350 ("btrfs: zoned: fix data relocation block group reservation")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/zoned.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 6e66ec491181..ba444e412613 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2588,9 +2588,9 @@ void btrfs_zoned_reserve_data_reloc_bg(struct btrfs_fs_info *fs_info)
 			spin_lock(&space_info->lock);
 			space_info->total_bytes -= bg->length;
 			space_info->disk_total -= bg->length * factor;
+			space_info->disk_total -= bg->zone_unusable;
 			/* There is no allocation ever happened. */
 			ASSERT(bg->used == 0);
-			ASSERT(bg->zone_unusable == 0);
 			/* No super block in a block group on the zoned setup. */
 			ASSERT(bg->bytes_super == 0);
 			spin_unlock(&space_info->lock);
-- 
2.51.0

Re: [PATCH] btrfs: zoned: fix incorrect ASSERT in btrfs_zoned_reserve_data_reloc_bg

[Naohiro Aota]

On Fri Sep 5, 2025 at 10:54 PM JST, Johannes Thumshirn wrote:
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> When moving a block-group to the dedicated data relocation space-info in
> btrfs_zoned_reserve_data_reloc_bg() it is ASSERT()ed that the newly
> created block-group for data relocation does not contain any zone_unusable
> bytes.
>
> But on disks with zone_capacity < zone_size, the difference between
> zone_size and zone_capacity is accounted as zone_unusable.
>
> Instead of ASSERT()ing that the block-group does not contain any
> zone_unusable bytes, remove them from the block-groups total size.
>
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Link: https://lore.kernel.org/linux-block/CAHj4cs8-cS2E+-xQ-d2Bj6vMJZ+CwT_cbdWBTju4BV35LsvEYw@mail.gmail.com/
> Fixes: daa0fde322350 ("btrfs: zoned: fix data relocation block group reservation")
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>

Re: [PATCH] btrfs: zoned: fix incorrect ASSERT in btrfs_zoned_reserve_data_reloc_bg

[Yi Zhang]

On Tue, Sep 9, 2025 at 12:42 PM Naohiro Aota <Naohiro.Aota@wdc.com> wrote:
>
> On Fri Sep 5, 2025 at 10:54 PM JST, Johannes Thumshirn wrote:
> > From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> >
> > When moving a block-group to the dedicated data relocation space-info in
> > btrfs_zoned_reserve_data_reloc_bg() it is ASSERT()ed that the newly
> > created block-group for data relocation does not contain any zone_unusable
> > bytes.
> >
> > But on disks with zone_capacity < zone_size, the difference between
> > zone_size and zone_capacity is accounted as zone_unusable.
> >
> > Instead of ASSERT()ing that the block-group does not contain any
> > zone_unusable bytes, remove them from the block-groups total size.
> >
> > Reported-by: Yi Zhang <yi.zhang@redhat.com>
> > Link: https://lore.kernel.org/linux-block/CAHj4cs8-cS2E+-xQ-d2Bj6vMJZ+CwT_cbdWBTju4BV35LsvEYw@mail.gmail.com/
> > Fixes: daa0fde322350 ("btrfs: zoned: fix data relocation block group reservation")
> > Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>

Thanks for the patch:

Tested-by: Yi Zhang <yi.zhang@redhat.com>


-- 
Best Regards,
  Yi Zhang