[Devel] [PATCH hci-8.1 v3 4/5] dm-ploop: reload metadata on resume

[no-reply at sashiko.virtuozzo.com]

> On "dmsetup reload" the new ploop reads metadata of the images in
> ploop_ctr(), but IO continues through the old ploop until the device
> is suspended. So the old ploop may change BAT and sizes of the delta
> files, and after resume the new ploop works with outdated metadata,
> e.g. allocates clusters already used by the old one or relies on a
> wrong file size. Also userspace may modify images of suspended device
> (e.g. merge zeroes BAT entries of the base delta, snapshot creation
> trims the tail of the top delta).
> 
> Reload all the metadata in ploop_preresume(): re-read header of the top
> delta, BAT of every delta and sizes of delta files, and rebuild BAT
> tree and holes_bitmap from scratch. On error the old metadata is kept
> and resume fails.
> 
> Skip the in-use signature check on reload, as the image is already
> [ ... ]
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-148171
> Feature: dm-ploop: ploop target driver
> 
> Signed-off-by: Alexander Ivanov <alexander.ivanov at virtuozzo.com>

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

-- 
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261008140333.614909-1-alexander.ivanov@virtuozzo.com?part=4