Re: [Devel] [PATCH hci-8.1 v9 06/10] dm-qcow2: keep the dirty bit of an image that needs check

[no-reply@sashiko.virtuozzo.com]

> The dm-qcow2 module parameter kernel_sets_dirty_bit makes the kernel set
> the dirty bit on resume and clear it on postsuspend. It is off by
> default and Virtuozzo does not set it: ploop manages the dirty bit from
> userspace itself. So this is a hardening patch for the non-default mode.
> 
> With kernel_sets_dirty_bit, postsuspend clears the dirty bit
> unconditionally. An image that is dirty at open, e.g. after a crash,
> has unrepaired refcounts, which may be below real usage, yet it is
> marked clean on disk after the first suspend. A userspace check before
> the next open then has no reason to repair it. The same happens after
> an error that sets wants_check, e.g. md_writeback_error: it is kept only
> in the target, so resume is refused, but after a table reload or a host
> restart the image is reopened with a clean header.
> 
> Clear the bit only if the image was clean before the kernel set it and
> [ ... ]
> clear a bit set by userspace while the device was suspended.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-148171
> Feature: dm-qcow2: block device over QCOW2 files driver
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>

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

-- 
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261028150645.3222391-1-alexander.ivanov@virtuozzo.com?part=6


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