[Devel] [PATCH hci-8.1 v6 4/7] block/blk-cbt: don't overwrite a map page with CBT_PAGE_MISSED

[no-reply at sashiko.virtuozzo.com]

> The cache flush marks a missing map page with CBT_PAGE_MISSED from an
> IPI, with a plain store. A page installed in between, by
> cbt_page_alloc(), is then overwritten: it leaks, and the bits already
> set in it are lost.
> 
> Store the marker with cmpxchg() only into an empty slot, and set the
> bits in the page if one appeared meanwhile.
> 
> 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=4