this patch adds iscsi_truncate which effectively allows for online resizing of iscsi volumes. for this to work you have to resize the volume on your storage and then call block_resize command in qemu which will issue a readcapacity16 to update the capacity.
v3: - remove switch statement in iscsi_open - create separate patch for brdv_drain_all() in bdrv_truncate() v2: - add a general bdrv_drain_all() before bdrv_truncate() to avoid in-flight AIOs while the device is truncated - since no AIOs are in flight we can use a sync libiscsi call to re-read the capacity - factor out the readcapacity16 logic as it is redundant to iscsi_open() and iscsi_truncate(). Signed-off-by: Peter Lieven <p...@kamp.de> --- block/iscsi.c | 77 +++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 56 insertions(+), 21 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index deb3b68..105533c 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -823,6 +823,35 @@ static void iscsi_nop_timed_event(void *opaque) } #endif +static int iscsi_disk_readcapacity16_sync(IscsiLun *iscsilun) { + struct scsi_task *task = NULL; + struct scsi_readcapacity16 *rc16 = NULL; + + task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun); + if (task == NULL) { + error_report("iSCSI: failed to send readcapacity16 command."); + return -EINVAL; + } + if (task->status != SCSI_STATUS_GOOD) { + error_report("iSCSI: failed to send readcapacity16 command."); + scsi_free_scsi_task(task); + return -EINVAL; + } + rc16 = scsi_datain_unmarshall(task); + if (rc16 == NULL) { + error_report("iSCSI: Failed to unmarshall readcapacity16 data."); + scsi_free_scsi_task(task); + return -EINVAL; + } + + iscsilun->block_size = rc16->block_length; + iscsilun->num_blocks = rc16->returned_lba + 1; + + scsi_free_scsi_task(task); + + return 0; +} + /* * We support iscsi url's on the form * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun> @@ -835,7 +864,6 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) struct scsi_task *task = NULL; struct scsi_inquiry_standard *inq = NULL; struct scsi_readcapacity10 *rc10 = NULL; - struct scsi_readcapacity16 *rc16 = NULL; char *initiator_name = NULL; int ret; @@ -926,25 +954,14 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) iscsilun->type = inq->periperal_device_type; scsi_free_scsi_task(task); + task = NULL; - switch (iscsilun->type) { - case TYPE_DISK: - task = iscsi_readcapacity16_sync(iscsi, iscsilun->lun); - if (task == NULL || task->status != SCSI_STATUS_GOOD) { - error_report("iSCSI: failed to send readcapacity16 command."); - ret = -EINVAL; - goto out; - } - rc16 = scsi_datain_unmarshall(task); - if (rc16 == NULL) { - error_report("iSCSI: Failed to unmarshall readcapacity16 data."); - ret = -EINVAL; + if (iscsilun->type == TYPE_DISK) { + if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) { goto out; } - iscsilun->block_size = rc16->block_length; - iscsilun->num_blocks = rc16->returned_lba + 1; - break; - case TYPE_ROM: + } + if (iscsilun->type == TYPE_ROM) { task = iscsi_readcapacity10_sync(iscsi, iscsilun->lun, 0, 0); if (task == NULL || task->status != SCSI_STATUS_GOOD) { error_report("iSCSI: failed to send readcapacity10 command."); @@ -964,10 +981,7 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) } else { iscsilun->num_blocks = rc10->lba + 1; } - break; - default: - break; - } + } bs->total_sectors = iscsilun->num_blocks * iscsilun->block_size / BDRV_SECTOR_SIZE ; @@ -1023,6 +1037,26 @@ static void iscsi_close(BlockDriverState *bs) memset(iscsilun, 0, sizeof(IscsiLun)); } +static int iscsi_truncate(BlockDriverState *bs, int64_t offset) +{ + IscsiLun *iscsilun = bs->opaque; + int ret = 0; + + if (iscsilun->type != TYPE_DISK) { + return -ENOTSUP; + } + + if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) { + return ret; + } + + if (offset > iscsi_getlength(bs)) { + return -EINVAL; + } + + return 0; +} + static int iscsi_has_zero_init(BlockDriverState *bs) { return 0; @@ -1093,6 +1127,7 @@ static BlockDriver bdrv_iscsi = { .create_options = iscsi_create_options, .bdrv_getlength = iscsi_getlength, + .bdrv_truncate = iscsi_truncate, .bdrv_aio_readv = iscsi_aio_readv, .bdrv_aio_writev = iscsi_aio_writev, -- 1.7.9.5