Le Monday 30 Sep 2013 à 13:36:55 (+0200), Benoît Canet a écrit :
> This field is used by blkverify to disable external snapshots creation.
> I will also be used by block filters like quorum to disable external snapshots
> creation.
>
> Signed-off-by: Benoit Canet <ben...@irqsave.net>
> ---
> block.c | 14 ++++++++++++++
> block/blkverify.c | 2 ++
> blockdev.c | 5 +++++
> include/block/block.h | 14 ++++++++++++++
> include/block/block_int.h | 6 ++++++
> 5 files changed, 41 insertions(+)
>
> diff --git a/block.c b/block.c
> index 93e113a..d54b5e2 100644
> --- a/block.c
> +++ b/block.c
> @@ -4632,3 +4632,17 @@ int bdrv_amend_options(BlockDriverState *bs,
> QEMUOptionParameter *options)
> }
> return bs->drv->bdrv_amend_options(bs, options);
> }
> +
> +ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs)
> +{
> + /* external snashots are allowed by defaults */
> + if (!bs->drv->bdrv_check_ext_snapshot) {
> + return EXT_SNAPSHOT_ALLOWED;
> + }
> + return bs->drv->bdrv_check_ext_snapshot(bs);
> +}
> +
> +ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs)
> +{
> + return EXT_SNAPSHOT_FORBIDDEN;
> +}
> diff --git a/block/blkverify.c b/block/blkverify.c
> index 2077d8a..b64c638 100644
> --- a/block/blkverify.c
> +++ b/block/blkverify.c
> @@ -313,6 +313,8 @@ static BlockDriver bdrv_blkverify = {
> .bdrv_aio_readv = blkverify_aio_readv,
> .bdrv_aio_writev = blkverify_aio_writev,
> .bdrv_aio_flush = blkverify_aio_flush,
> +
> + .bdrv_check_ext_snapshot = bdrv_check_ext_snapshot_forbidden,
> };
>
> static void bdrv_blkverify_init(void)
> diff --git a/blockdev.c b/blockdev.c
> index 8aa66a9..92029d8 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1131,6 +1131,11 @@ static void
> external_snapshot_prepare(BlkTransactionState *common,
> }
> }
>
> + if (bdrv_check_ext_snapshot(state->old_bs) != EXT_SNAPSHOT_ALLOWED) {
> + error_set(errp, QERR_FEATURE_DISABLED, "snapshot");
> + return;
> + }
> +
> flags = state->old_bs->open_flags;
>
> /* create new image w/backing file */
> diff --git a/include/block/block.h b/include/block/block.h
> index f808550..2bf0e12 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -244,6 +244,20 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult
> *res, BdrvCheckMode fix);
>
> int bdrv_amend_options(BlockDriverState *bs_new, QEMUOptionParameter
> *options);
>
> +/* external snapshots */
> +
> +typedef enum {
> + EXT_SNAPSHOT_ALLOWED,
> + EXT_SNAPSHOT_FORBIDDEN,
> +} ExtSnapshotPerm;
> +
> +/* return EXT_SNAPSHOT_ALLOWED if external snapshot is allowed
> + * return EXT_SNAPSHOT_FORBIDEN if external snapshot is forbiden
> + */
> +ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs);
> +/* helper used to forbid external snapshots like in blkverify */
> +ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs);
> +
> /* async block I/O */
> typedef void BlockDriverDirtyHandler(BlockDriverState *bs, int64_t sector,
> int sector_num);
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 211087a..e6a14ae 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -67,6 +67,12 @@ typedef struct BdrvTrackedRequest {
> struct BlockDriver {
> const char *format_name;
> int instance_size;
> +
> + /* if not defined external snapshots are allowed
> + * future block filters will query their children to build the response
> + */
> + ExtSnapshotPerm (*bdrv_check_ext_snapshot)(BlockDriverState *bs);
> +
> int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char
> *filename);
> int (*bdrv_probe_device)(const char *filename);
>
> --
> 1.8.1.2
>
>
Well this doesn't work with protocols.
When using quorum info block show virtio1 as raw.
When doing a snapshot with quorum snapshot "desactivated" by this patch it seems
blockdev is manipulating a raw BlockDriverState and not the quorum one so
this fail.
(qemu) info block
virtio0: /home/benoit/images/debian.raw (raw)
[not inserted]
virtio1: (raw) <- quorum
[not inserted]
ide1-cd0: [not inserted]
Removable device: not locked, tray closed
(qemu) snapshot_blkdev virtio1 blah
Could not open '': Could not open '': No such file or directory: No such file or
(qemu) qemu: terminating on signal 2
Kevin: Is making quorum a protocol a good idea to start with ?
Do you have an idea on how to fix this ?
Best regards
Benoît
