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 <[email protected]> --- 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
