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>
diff --git a/block/iscsi.c b/block/iscsi.c
index 439af6f..3d52921 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -938,6 +938,71 @@
}
#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 @@
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 @@
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 @@
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 @@
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 @@
.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,
