[Devel] [PATCH hci-8.1 v7 0/8] block/blk-cbt: don't lose writes held across a dm suspend

[Konstantin Khorenko]

Not applying v7 yet: the REQ_NOWAIT question in the 8/8 reply decides
between applying v7 and a v8.

On 10/28/26 11:11, Pavel Tikhomirov wrote:
> Fix CBT missing writes that request-based dm holds across a suspend,
> which made incremental backups taken with ploop-backup silently lose
> data.

- VSTOR-149268, which all eight commits name, is already resolved.
  Please reopen it or file a separate bug for this series and put that
  into the commits.
- Fixes: tags, in v8 or added on my side if v7 goes in:
  - 1/8, 6/8: 458bca130a8e ("block/blk-cbt: allow multiple cbts in a
    single queue")
  - 2/8, 3/8, 4/8, 5/8, 7/8, 8/8: e713742e2ee6 ("cbt: introduce changed
    block tracking")

The review also found four old CBT bugs, not introduced by this series
and not blocking it. I created tasks for them and assigned them to you,
the details are in the descriptions:

- https://virtuozzo.atlassian.net/browse/VSTOR-153220
  NULL dereference in cbt_page_alloc() on BLKCBTSTOP during a write
- https://virtuozzo.atlassian.net/browse/VSTOR-153221
  crash in CBT_SNAP_CREATE after a failed bitmap page allocation
- https://virtuozzo.atlassian.net/browse/VSTOR-153222
  an extent evicted from the per-cpu cache misses the snapshot
- https://virtuozzo.atlassian.net/browse/VSTOR-153223
  a write allocating a bitmap page during a resize is lost

-- 
Konstantin Khorenko,
Virtuozzo Linux Kernel Team