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Re: [Qemu-devel] [PATCH v2 06/10] block: Forbid trying to change unsuppo
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v2 06/10] block: Forbid trying to change unsupported options during reopen |
Date: |
Wed, 5 Sep 2018 14:48:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 2018-09-03 16:34, Alberto Garcia wrote:
> The bdrv_reopen_prepare() function checks all options passed to each
> BlockDriverState (in the reopen_state->options QDict) and makes all
> necessary preparations to apply the option changes requested by the
> user.
>
> Options are removed from the QDict as they are processed, so at the
> end of bdrv_reopen_prepare() only the options that can't be changed
> are left. Then a loop goes over all remaining options and verifies
> that the old and new values are identical, returning an error if
> they're not.
>
> The problem is that at the moment there are options that are removed
> from the QDict although they can't be changed. The consequence of this
> is any modification to any of those options is silently ignored:
>
> (qemu) qemu-io virtio0 "reopen -o discard=on"
>
> This happens when all options from bdrv_runtime_opts are removed
> from the QDict but then only a few of them are processed. Since
> it's especially important that "node-name" and "driver" are not
> changed, the code puts them back into the QDict so they are checked
> at the end of the function. Instead of putting only those two options
> back into the QDict, this patch puts all unprocessed options using
> qemu_opts_to_qdict().
>
> update_flags_from_options() also needs to be modified to prevent
> BDRV_OPT_CACHE_NO_FLUSH, BDRV_OPT_CACHE_DIRECT and BDRV_OPT_READ_ONLY
> from going back to the QDict.
>
> Signed-off-by: Alberto Garcia <address@hidden>
> ---
> block.c | 22 +++++++---------------
> 1 file changed, 7 insertions(+), 15 deletions(-)
Reviewed-by: Max Reitz <address@hidden>
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- Re: [Qemu-devel] [PATCH v2 03/10] block: Remove child references from bs->{options, explicit_options}, (continued)
- [Qemu-devel] [PATCH v2 05/10] block: Allow child references on reopen, Alberto Garcia, 2018/09/03
- [Qemu-devel] [PATCH v2 09/10] block: Allow changing 'detect-zeroes' on reopen, Alberto Garcia, 2018/09/03
- [Qemu-devel] [PATCH v2 08/10] block: Allow changing 'discard' on reopen, Alberto Garcia, 2018/09/03
- [Qemu-devel] [PATCH v2 02/10] file-posix: x-check-cache-dropped should default to false on reopen, Alberto Garcia, 2018/09/03
- [Qemu-devel] [PATCH v2 06/10] block: Forbid trying to change unsupported options during reopen, Alberto Garcia, 2018/09/03
- Re: [Qemu-devel] [PATCH v2 06/10] block: Forbid trying to change unsupported options during reopen,
Max Reitz <=
- [Qemu-devel] [PATCH v2 07/10] file-posix: Forbid trying to change unsupported options during reopen, Alberto Garcia, 2018/09/03