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Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic blo
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change |
Date: |
Wed, 27 Jul 2011 17:43:08 +0400 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.16) Gecko/20110704 Icedove/3.0.11 |
27.07.2011 15:30, Supriya Kannery wrote:
> New command "block_set" added for dynamically changing any of the block
> device parameters. For now, dynamic setting of hostcache params using this
> command is implemented. Other block device parameter changes, can be
> integrated in similar lines.
>
> Signed-off-by: Supriya Kannery <address@hidden>
>
> ---
> block.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
> block.h | 2 +
> blockdev.c | 61
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> blockdev.h | 1
> hmp-commands.hx | 14 ++++++++++++
> qemu-config.c | 13 +++++++++++
> qemu-option.c | 25 ++++++++++++++++++++++
> qemu-option.h | 2 +
> qmp-commands.hx | 28 +++++++++++++++++++++++++
> 9 files changed, 200 insertions(+)
>
> Index: qemu/block.c
> ===================================================================
> --- qemu.orig/block.c
> +++ qemu/block.c
> @@ -651,6 +651,34 @@ unlink_and_fail:
> return ret;
> }
>
> +int bdrv_reopen(BlockDriverState *bs, int bdrv_flags)
> +{
> + BlockDriver *drv = bs->drv;
> + int ret = 0, open_flags;
> +
> + /* Quiesce IO for the given block device */
> + qemu_aio_flush();
> + if (bdrv_flush(bs)) {
> + qerror_report(QERR_DATA_SYNC_FAILED, bs->device_name);
> + return ret;
> + }
> + open_flags = bs->open_flags;
> + bdrv_close(bs);
> +
> + ret = bdrv_open(bs, bs->filename, bdrv_flags, drv);
> + if (ret < 0) {
> + /* Reopen failed. Try to open with original flags */
> + qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename);
> + ret = bdrv_open(bs, bs->filename, open_flags, drv);
> + if (ret < 0) {
> + /* Reopen failed with orig and modified flags */
> + abort();
> + }
Can we please avoid this stuff completely? Just keep the
old device open still, until you're sure new one is ok.
Or else it will be quite dangerous command in many cases.
For example, after -runas/-chroot, or additional selinux
settings or whatnot. And in this case, instead of merely
returning an error, we'll see abort(). Boom.
Thanks,
/mjt
- Re: [Qemu-devel] [V5 Patch 1/4]Qemu: Enhance "info block" to display host cache setting, (continued)
- [Qemu-devel] [V5 Patch 2/4]Qemu: qerrors for file reopen, data sync and cmd syntax, Supriya Kannery, 2011/07/27
- [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Supriya Kannery, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Anthony Liguori, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Stefan Hajnoczi, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Anthony Liguori, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Stefan Hajnoczi, 2011/07/28
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Supriya Kannery, 2011/07/28
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Anthony Liguori, 2011/07/28
Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change,
Michael Tokarev <=
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Anthony Liguori, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Stefan Hajnoczi, 2011/07/27
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Kevin Wolf, 2011/07/28
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Stefan Hajnoczi, 2011/07/28
- Re: [Qemu-devel] [V5 Patch 3/4]Qemu: Command "block_set" for dynamic block params change, Kevin Wolf, 2011/07/28
[Qemu-devel] [V5 Patch 4/4]Qemu: Add commandline -drive option 'hostcache', Supriya Kannery, 2011/07/27