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Re: [Qemu-block] [PATCH v2 06/21] block: Exclude nested options only for
From: |
Max Reitz |
Subject: |
Re: [Qemu-block] [PATCH v2 06/21] block: Exclude nested options only for children in append_open_options() |
Date: |
Fri, 27 Nov 2015 19:02:27 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 |
On 27.11.2015 18:58, Max Reitz wrote:
> On 23.11.2015 16:59, Kevin Wolf wrote:
>> Some drivers have nested options (e.g. blkdebug rule arrays), which
>> don't belong to a child node and shouldn't be removed. Don't remove all
>> options with "." in their name, but check for the complete prefixes of
>> actually existing child nodes.
>>
>> Signed-off-by: Kevin Wolf <address@hidden>
>> ---
>> block.c | 19 +++++++++++++++----
>> include/block/block_int.h | 1 +
>> 2 files changed, 16 insertions(+), 4 deletions(-)
>
> Thanks, now I don't need to fix it myself. :-)
>
> (I would have had to do that for an in-work series of mine)
>
>> diff --git a/block.c b/block.c
>> index 23d9e10..02125e2 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -1101,11 +1101,13 @@ static int bdrv_fill_options(QDict **options, const
>> char **pfilename,
>>
>> static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
>> BlockDriverState *child_bs,
>> + const char *child_name,
>> const BdrvChildRole *child_role)
>> {
>> BdrvChild *child = g_new(BdrvChild, 1);
>> *child = (BdrvChild) {
>> .bs = child_bs,
>> + .name = child_name,
>> .role = child_role,
>> };
>>
>> @@ -1165,7 +1167,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs,
>> BlockDriverState *backing_hd)
>> bs->backing = NULL;
>> goto out;
>> }
>> - bs->backing = bdrv_attach_child(bs, backing_hd, &child_backing);
>> + bs->backing = bdrv_attach_child(bs, backing_hd, "backing",
>> &child_backing);
>> bs->open_flags &= ~BDRV_O_NO_BACKING;
>> pstrcpy(bs->backing_file, sizeof(bs->backing_file),
>> backing_hd->filename);
>> pstrcpy(bs->backing_format, sizeof(bs->backing_format),
>> @@ -1322,7 +1324,7 @@ BdrvChild *bdrv_open_child(const char *filename,
>> goto done;
>> }
>>
>> - c = bdrv_attach_child(parent, bs, child_role);
>> + c = bdrv_attach_child(parent, bs, bdref_key, child_role);
>>
>> done:
>> qdict_del(options, bdref_key);
>> @@ -3952,13 +3954,22 @@ static bool append_open_options(QDict *d,
>> BlockDriverState *bs)
>> {
>> const QDictEntry *entry;
>> QemuOptDesc *desc;
>> + BdrvChild *child;
>> bool found_any = false;
>> + const char *p;
>>
>> for (entry = qdict_first(bs->options); entry;
>> entry = qdict_next(bs->options, entry))
>> {
>> - /* Only take options for this level */
>> - if (strchr(qdict_entry_key(entry), '.')) {
>> + /* Exclude options for children */
>> + QLIST_FOREACH(child, &bs->children, next) {
>> + if (strstart(qdict_entry_key(entry), child->name, &p)
>> + && (!*p || *p == '.'))
>> + {
>> + break;
>> + }
>> + }
>> + if (child) {
>> continue;
>> }
>>
>
> A good general solution, but I think bdrv_refresh_filename() may be bad
> enough to break with general solutions. ;-)
>
> bdrv_refresh_filename() only considers "file" and "backing" (actually,
> it only supports "file" for now, I'm working on "backing", though). The
> only drivers with other children are quorum, blkdebug, blkverify and
> VMDK. The former three have their own implementation of
> bdrv_refresh_filename(), so they don't use append_open_options() at all.
> The latter, however, (VMDK) does not.
>
> This change to append_open_options results in the extent.%d options
> simply being omitted altogether because bdrv_refresh_filename() does not
> fetch them. Before, they were included in the VMDK BDS's options, which
> is not ideal but works more or less.
>
> In order to "fix" this, I see three ways right now:
> 1. Just care about "file" and "backing". bdrv_refresh_filename()
> doesn't support anything else, so that will be fine.
> 2. Implement bdrv_refresh_filename() specifically for VMDK so
> append_open_options() will never have to handle anything but "file"
> and "backing".
> 3. Fix bdrv_refresh_filename() so that it handles all children and not
> just "file" and "backing".
>
> Since we are shooting for 2.6 anyway (I assume ;-)), I think we should
> go for option 3. This means that this patch is fine, and I'll see to
> fixing bdrv_refresh_filename() (because I'm working on that anyway).
>
> Reviewed-by: Max Reitz <address@hidden>
Oops, focused so much on this that I missed the issue Wen Congyang
found. So this R-b is assuming that is fixed *cough*.
Max
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- [Qemu-block] [PATCH v2 00/21] block: Cache mode for children etc., Kevin Wolf, 2015/11/23
- [Qemu-block] [PATCH v2 03/21] mirror: Error out when a BDS would get two BBs, Kevin Wolf, 2015/11/23
- [Qemu-block] [PATCH v2 01/21] qcow2: Add .bdrv_join_options callback, Kevin Wolf, 2015/11/23
- [Qemu-block] [PATCH v2 07/21] block: Pass driver-specific options to .bdrv_refresh_filename(), Kevin Wolf, 2015/11/23
- [Qemu-block] [PATCH v2 09/21] block: Allow specifying child options in reopen, Kevin Wolf, 2015/11/23