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[Qemu-devel] Re: [PATCH 3/3] block: Fix the use of protocols in backing
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] Re: [PATCH 3/3] block: Fix the use of protocols in backing files |
Date: |
Thu, 02 Dec 2010 15:31:42 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 |
Am 30.11.2010 16:14, schrieb Stefan Hajnoczi:
> Backing filenames may contain a protocol. The code currently doesn't
> consider this case and produces filenames that embed "<protocol>:".
> Don't combine filenames if the backing filename contains a protocol.
>
> Based on an earlier patch by Anthony Liguori <address@hidden>.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> block.c | 15 +++++++++++----
> 1 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/block.c b/block.c
> index 59b69e4..c9a6720 100644
> --- a/block.c
> +++ b/block.c
> @@ -611,10 +611,17 @@ int bdrv_open(BlockDriverState *bs, const char
> *filename, int flags,
> BlockDriver *back_drv = NULL;
>
> bs->backing_hd = bdrv_new("");
> - path_combine(backing_filename, sizeof(backing_filename),
> - filename, bs->backing_file);
> - if (bs->backing_format[0] != '\0')
> - back_drv = bdrv_find_format(bs->backing_format);
> + if (path_has_protocol(bs->backing_file)) {
> + back_drv = bdrv_find_protocol(bs->backing_file);
> + pstrcpy(backing_filename, sizeof(backing_filename),
> + bs->backing_file);
> + } else {
> + path_combine(backing_filename, sizeof(backing_filename),
> + filename, bs->backing_file);
> + if (bs->backing_format[0] != '\0') {
> + back_drv = bdrv_find_format(bs->backing_format);
> + }
> + }
Now we ignore bs->backing_format when a protocol is used. We don't even
allow using anything on top of that protocol any more, so for example
qcow2 over sheepdog would be broken. Maybe a use case that you like
better would be QED over http or something.
It might still not be a very common use case, but this doesn't look
right to me. Probably only the pstrcpy/path_combine should be conditional.
I've applied the first two patches of the series to the block branch.
Kevin
- [Qemu-devel] Re: [PATCH 3/3] block: Fix the use of protocols in backing files,
Kevin Wolf <=