On Thu, Sep 26, 2013 at 04:33:49PM +0200, Benoît Canet wrote: > 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 | 7 +++++++ > include/block/block_int.h | 8 ++++++++ > 5 files changed, 36 insertions(+) > > diff --git a/block.c b/block.c > index 4833b37..4da6fd9 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); > } > + > +bool bdrv_check_ext_snapshot(BlockDriverState *bs) > +{ > + /* external snashots are enabled by defaults */ > + if (!bs->drv->bdrv_check_ext_snapshot) { > + return true; > + } > + return bs->drv->bdrv_check_ext_snapshot(bs); > +} > + > +bool bdrv_forbid_ext_snapshot(BlockDriverState *bs) > +{ > + return false; > +}
The only problem I have with this now, is that "bdrv_forbid_ext_snapshot()" returns false, to indicate that "forbid ext snapshot" is true. Looking at the function above, I would come to the opposite conclusion as to what it does. I understand why - you want the function name assigned to .bdrv_check_ext_snapshot to reflect the action, but then that causes the boolean return to be misleading. Maybe returning an enum would be more natural? I apologize if this seems too pedantic. :) Thanks, Jeff > diff --git a/block/blkverify.c b/block/blkverify.c > index 2077d8a..c548923 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_forbid_ext_snapshot, > }; > > static void bdrv_blkverify_init(void) > diff --git a/blockdev.c b/blockdev.c > index 8aa66a9..5c16f1b 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)) { > + 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..df19610 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -244,6 +244,13 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult > *res, BdrvCheckMode fix); > > int bdrv_amend_options(BlockDriverState *bs_new, QEMUOptionParameter > *options); > > +/* external snapshots */ > + > +/* return true if external snapshot is allowed, false if not */ > +bool bdrv_check_ext_snapshot(BlockDriverState *bs); > +/* helper used to forbid external snapshots like in blkverify */ > +bool bdrv_forbid_ext_snapshot(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..cb92355 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -67,6 +67,14 @@ typedef struct BdrvTrackedRequest { > struct BlockDriver { > const char *format_name; > int instance_size; > + > + /* if not defined external snapshots are allowed > + * if return true external snapshots are allowed > + * if return false external snapshots are not allowed > + * future block filters will query their children to build the response > + */ > + bool (*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 > >