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Re: [Qemu-devel] [RFC Patch 4/7]Qemu: Framework for reopening image file
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [RFC Patch 4/7]Qemu: Framework for reopening image files safely |
Date: |
Tue, 7 Feb 2012 10:08:36 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Feb 01, 2012 at 08:36:58AM +0530, Supriya Kannery wrote:
> Struct BDRVReopenState along with three reopen related functions
> introduced for handling reopening of images safely. This can be
> extended by each of the block drivers to reopen respective
> image files.
>
> Signed-off-by: Supriya Kannery <address@hidden>
>
> Index: qemu/block.c
> ===================================================================
> --- qemu.orig/block.c
> +++ qemu/block.c
> @@ -808,10 +808,32 @@ unlink_and_fail:
> return ret;
> }
>
> +int bdrv_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs, int
> flags)
> +{
> + BlockDriver *drv = bs->drv;
> +
> + return drv->bdrv_reopen_prepare(bs, prs, flags);
Indentation should be 4 spaces. I suggest configuring your editor so
this is always correct and done automatically.
> +}
> +
> +void bdrv_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
> +{
> + BlockDriver *drv = bs->drv;
> +
> + drv->bdrv_reopen_commit(bs, rs);
> +}
> +
> +void bdrv_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
> +{
> + BlockDriver *drv = bs->drv;
> +
> + drv->bdrv_reopen_abort(bs, rs);
> +}
> +
> int bdrv_reopen(BlockDriverState *bs, int bdrv_flags)
> {
> BlockDriver *drv = bs->drv;
> int ret = 0, open_flags;
> + BDRVReopenState *reopen_state = NULL;
>
> /* Quiesce IO for the given block device */
> qemu_aio_flush();
> @@ -820,17 +842,32 @@ int bdrv_reopen(BlockDriverState *bs, in
> 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);
> + /* Use driver specific reopen() if available */
> + if (drv->bdrv_reopen_prepare) {
> + ret = bdrv_reopen_prepare(bs, &reopen_state, bdrv_flags);
> + if (ret < 0) {
Indentation
> + bdrv_reopen_abort(bs, reopen_state);
> + qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename);
> + return ret;
> + }
> +
> + bdrv_reopen_commit(bs, reopen_state);
> + bs->open_flags = bdrv_flags;
Is bs->open_flags not assigned inside bdrv_reopen_*()?
> +
> + } else {
> + open_flags = bs->open_flags;
> + bdrv_close(bs);
> +
> + ret = bdrv_open(bs, bs->filename, bdrv_flags, drv);
> if (ret < 0) {
> - /* Reopen failed with orig and modified flags */
> - abort();
> + /* 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 */
> + bs->drv = NULL;
This should be a post-condition of bdrv_open(). If you have found a
case where bs->drv != NULL after bdrv_open() fails, then please fix that
code path instead of assigning NULL here.
- Re: [Qemu-devel] [RFC Patch 4/7]Qemu: Framework for reopening image files safely,
Stefan Hajnoczi <=