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Re: [PATCH 1/3] block: Activate recursively even for already active node
From: |
Kevin Wolf |
Subject: |
Re: [PATCH 1/3] block: Activate recursively even for already active nodes |
Date: |
Wed, 18 Dec 2019 18:02:24 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
Am 17.12.2019 um 15:59 hat Kevin Wolf geschrieben:
> bdrv_invalidate_cache_all() assumes that all nodes in a given subtree
> are either active or inactive when it starts. Therefore, as soon as it
> arrives at an already active node, it stops.
>
> However, this assumption is wrong. For example, it's possible to take a
> snapshot of an inactive node, which results in an active overlay over an
> inactive backing file. The active overlay is probably also the root node
> of an inactive BlockBackend (blk->disable_perm == true).
>
> In this case, bdrv_invalidate_cache_all() does not need to do anything
> to activate the overlay node, but it still needs to recurse into the
> children and the parents to make sure that after returning success,
> really everything is activated.
>
> Signed-off-by: Kevin Wolf <address@hidden>
Actually:
Cc: address@hidden