[Devel] [PATCH hci-8.1 v6 6/7] block/blk-cbt: don't sleep in CBT for a REQ_NOWAIT write

[no-reply at sashiko.virtuozzo.com]

> Accounting a write in CBT may allocate a bitmap page with GFP_NOIO,
> either for the write itself or for the extent it evicts from the per-cpu
> cache, so a REQ_NOWAIT bio can sleep in submit_bio_noacct().
> 
> For a REQ_NOWAIT write, skip the cache and set the bits directly, which
> doesn't allocate when all the pages are there. If one is missing, fail
> the bio with BLK_STS_AGAIN, for the submitter to retry it in a context
> that may block. The throttle dispatch work may sleep, so it doesn't use
> this.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-149268
> Feature: cbt: changed block tracking (for backup)
> Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261027-ptikhomirov-vstor-149268-cbt-account-at-rq-start-v6-0-f9870cf5c7eb@virtuozzo.com?part=6