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iscsi: add iscsi_truncate support 

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.

v4:
  - factor out complete readcapacity logic into a separate function
  - handle capacity change check condition in readcapacity function
    (this happens if the block_resize cmd is the first iscsi task
    executed after a resize on the storage)

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 <pl@kamp.de>
[allow any type of unit attention check condition in iscsi_readcapacity_sync(),
 as in Message-ID: <51263A2A.6070304@dlhnet.de> - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Lieven 2013-02-18 14:50:46 +01:00 committed by Paolo Bonzini
parent 1dde716ed6
commit cb1b83e740
1 changed files with 88 additions and 47 deletions
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135
block/iscsi.c
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@ -938,6 +938,71 @@ static void iscsi_nop_timed_event(void *opaque)
}
#endif
static int iscsi_readcapacity_sync(IscsiLun *iscsilun)
{
struct scsi_task *task = NULL;
struct scsi_readcapacity10 *rc10 = NULL;
struct scsi_readcapacity16 *rc16 = NULL;
int ret = 0;
int retries = ISCSI_CMD_RETRIES;
try_again:
switch (iscsilun->type) {
case TYPE_DISK:
task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
if (task == NULL || task->status != SCSI_STATUS_GOOD) {
if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
&& task->sense.key == SCSI_SENSE_UNIT_ATTENTION
&& retries-- > 0) {
scsi_free_scsi_task(task);
goto try_again;
}
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;
goto out;
}
iscsilun->block_size = rc16->block_length;
iscsilun->num_blocks = rc16->returned_lba + 1;
break;
case TYPE_ROM:
task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);
if (task == NULL || task->status != SCSI_STATUS_GOOD) {
error_report("iSCSI: failed to send readcapacity10 command.");
ret = -EINVAL;
goto out;
}
rc10 = scsi_datain_unmarshall(task);
if (rc10 == NULL) {
error_report("iSCSI: Failed to unmarshall readcapacity10 data.");
ret = -EINVAL;
goto out;
}
iscsilun->block_size = rc10->block_size;
if (rc10->lba == 0) {
/* blank disk loaded */
iscsilun->num_blocks = 0;
} else {
iscsilun->num_blocks = rc10->lba + 1;
}
break;
default:
break;
}
out:
if (task) {
scsi_free_scsi_task(task);
}
return ret;
}
/*
* We support iscsi url's on the form
* iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
@ -949,8 +1014,6 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
struct iscsi_url *iscsi_url = NULL;
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;
@ -1040,50 +1103,9 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
iscsilun->type = inq->periperal_device_type;
scsi_free_scsi_task(task);
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;
goto out;
}
iscsilun->block_size = rc16->block_length;
iscsilun->num_blocks = rc16->returned_lba + 1;
break;
case 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.");
ret = -EINVAL;
goto out;
}
rc10 = scsi_datain_unmarshall(task);
if (rc10 == NULL) {
error_report("iSCSI: Failed to unmarshall readcapacity10 data.");
ret = -EINVAL;
goto out;
}
iscsilun->block_size = rc10->block_size;
if (rc10->lba == 0) {
/* blank disk loaded */
iscsilun->num_blocks = 0;
} else {
iscsilun->num_blocks = rc10->lba + 1;
}
break;
default:
break;
if ((ret = iscsi_readcapacity_sync(iscsilun)) != 0) {
goto out;
}
bs->total_sectors = iscsilun->num_blocks *
iscsilun->block_size / BDRV_SECTOR_SIZE ;
@ -1096,8 +1118,6 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
bs->sg = 1;
}
ret = 0;
#if defined(LIBISCSI_FEATURE_NOP_COUNTER)
/* Set up a timer for sending out iSCSI NOPs */
iscsilun->nop_timer = qemu_new_timer_ms(rt_clock, iscsi_nop_timed_event, iscsilun);
@ -1138,6 +1158,26 @@ 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_readcapacity_sync(iscsilun)) != 0) {
return ret;
}
if (offset > iscsi_getlength(bs)) {
return -EINVAL;
}
return 0;
}
static int iscsi_has_zero_init(BlockDriverState *bs)
{
return 0;
@ -1208,6 +1248,7 @@ 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,