Re: [Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank CDROM devices
On Sun, Aug 19, 2012 at 7:57 AM, Paolo Bonzini wrote: > Il 17/08/2012 04:36, Ronnie Sahlberg ha scritto: >> The number of blocks of the device is used to compute the device size >> in bdrv_getlength()/iscsi_getlength(). >> For MMC devices, the ReturnedLogicalBlockAddress in the READCAPACITY10 >> has a special meaning when it is 0. >> In this case it does not mean that LBA 0 is the last accessible LBA, >> and thus the device has 1 readable block, but instead it means that the >> disc is blank and there are no readable blocks. >> >> This change ensures that when the iSCSI LUN is loaded with a blank >> DVD-R disk or similar that bdrv_getlength() will return the correct >> size of the device as 0 bytes. >> >> Signed-off-by: Ronnie Sahlberg >> --- >> block/iscsi.c |7 ++- >> 1 files changed, 6 insertions(+), 1 deletions(-) >> >> diff --git a/block/iscsi.c b/block/iscsi.c >> index bb9cf82..fb420ea 100644 >> --- a/block/iscsi.c >> +++ b/block/iscsi.c >> @@ -717,7 +717,12 @@ iscsi_readcapacity10_cb(struct iscsi_context *iscsi, >> int status, >> } >> >> itask->iscsilun->block_size = rc10->block_size; >> -itask->iscsilun->num_blocks = rc10->lba + 1; >> +if (rc10->lba == 0) { >> +/* blank disk loaded */ >> +itask->iscsilun->num_blocks = 0; >> +} else { >> +itask->iscsilun->num_blocks = rc10->lba + 1; >> +} >> itask->bs->total_sectors= itask->iscsilun->num_blocks * >> itask->iscsilun->block_size / >> BDRV_SECTOR_SIZE ; >> >> > > Thanks, applied to SCSI branch. We'll see whether this hits 1.2. This patch only matters for the use case of having empty/blank media loaded into an iscsi cdrom. I doubt being able to "burn" data to an iscsi drive is very important or urgent, so it is fine with me to delay until post 1.2 regards ronnie sahlberg
Re: [Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank CDROM devices
Il 17/08/2012 04:36, Ronnie Sahlberg ha scritto: > The number of blocks of the device is used to compute the device size > in bdrv_getlength()/iscsi_getlength(). > For MMC devices, the ReturnedLogicalBlockAddress in the READCAPACITY10 > has a special meaning when it is 0. > In this case it does not mean that LBA 0 is the last accessible LBA, > and thus the device has 1 readable block, but instead it means that the > disc is blank and there are no readable blocks. > > This change ensures that when the iSCSI LUN is loaded with a blank > DVD-R disk or similar that bdrv_getlength() will return the correct > size of the device as 0 bytes. > > Signed-off-by: Ronnie Sahlberg > --- > block/iscsi.c |7 ++- > 1 files changed, 6 insertions(+), 1 deletions(-) > > diff --git a/block/iscsi.c b/block/iscsi.c > index bb9cf82..fb420ea 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -717,7 +717,12 @@ iscsi_readcapacity10_cb(struct iscsi_context *iscsi, int > status, > } > > itask->iscsilun->block_size = rc10->block_size; > -itask->iscsilun->num_blocks = rc10->lba + 1; > +if (rc10->lba == 0) { > +/* blank disk loaded */ > +itask->iscsilun->num_blocks = 0; > +} else { > +itask->iscsilun->num_blocks = rc10->lba + 1; > +} > itask->bs->total_sectors= itask->iscsilun->num_blocks * > itask->iscsilun->block_size / > BDRV_SECTOR_SIZE ; > > Thanks, applied to SCSI branch. We'll see whether this hits 1.2. Paolo
[Qemu-devel] [PATCH 1/2] ISCSI: Set number of blocks to 0 for blank CDROM devices
The number of blocks of the device is used to compute the device size in bdrv_getlength()/iscsi_getlength(). For MMC devices, the ReturnedLogicalBlockAddress in the READCAPACITY10 has a special meaning when it is 0. In this case it does not mean that LBA 0 is the last accessible LBA, and thus the device has 1 readable block, but instead it means that the disc is blank and there are no readable blocks. This change ensures that when the iSCSI LUN is loaded with a blank DVD-R disk or similar that bdrv_getlength() will return the correct size of the device as 0 bytes. Signed-off-by: Ronnie Sahlberg --- block/iscsi.c |7 ++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index bb9cf82..fb420ea 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -717,7 +717,12 @@ iscsi_readcapacity10_cb(struct iscsi_context *iscsi, int status, } itask->iscsilun->block_size = rc10->block_size; -itask->iscsilun->num_blocks = rc10->lba + 1; +if (rc10->lba == 0) { +/* blank disk loaded */ +itask->iscsilun->num_blocks = 0; +} else { +itask->iscsilun->num_blocks = rc10->lba + 1; +} itask->bs->total_sectors= itask->iscsilun->num_blocks * itask->iscsilun->block_size / BDRV_SECTOR_SIZE ; -- 1.7.3.1