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Re: [Qemu-block] [PATCH v2] block/dirty-bitmap: Documentation and Commen
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [PATCH v2] block/dirty-bitmap: Documentation and Comment fixups |
Date: |
Mon, 4 Feb 2019 09:00:44 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 2/1/19 7:10 PM, John Snow wrote:
> The meaning of the states has changed subtly over time,
> this should bring the understanding more in-line with the
> current, actual usages.
>
> Reported-by: Eric Blake <address@hidden>
> Signed-off-by: John Snow <address@hidden>
>
> ---
> V2: Amended some wordings, though this is a little chatty now.
> Hopefully it's clearer, though.
> ---
> /**
> - * A BdrvDirtyBitmap can be in three possible states:
> - * (1) successor is NULL and disabled is false: full r/w mode
> - * (2) successor is NULL and disabled is true: read only mode ("disabled")
> - * (3) successor is set: frozen mode.
> - * A frozen bitmap cannot be renamed, deleted, anonymized, cleared, set,
> - * or enabled. A frozen bitmap can only abdicate() or reclaim().
> + * A BdrvDirtyBitmap can be in four possible user-visible states:
> + * (1) Active: successor is NULL, and disabled is false: full r/w mode
> + * (2) Disabled: successor is NULL, and disabled is true: qualified r/w mode,
> + * guest writes are dropped, but monitor writes are possible,
> + * through commands like merge and clear.
> + * (3) Frozen: successor is not NULL.
> + * A frozen bitmap cannot be renamed, deleted, cleared, set,
> + * enabled, merged to, etc. A frozen bitmap can only abdicate()
> + * or reclaim().
> + * In this state, the anonymous successor bitmap may be either
> + * Active and recording writes from the guest (e.g. backup
> jobs),
> + * but it can be Disabled and not recording writes.
s/but/or/
> + * (4) Locked: Whether Active or Disabled, the user cannot modify this
> bitmap
> + * in any way from the monitor.
Worth a parenthetical comment mentioning NBD export as a possible reason
for Locked to be visible?
With the one word fix,
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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