Message ID | 1380206029-9740-2-git-send-email-benoit@irqsave.net |
---|---|
State | New |
Headers | show |
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 <benoit@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 > >
Am 26.09.2013 um 18:48 hat Jeff Cody geschrieben: > 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 <benoit@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. :) Perhaps rename the function to bdrv_check_ext_snapshot_forbidden() or something like that? Kevin
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; +} 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);
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 <benoit@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(+)