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.
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.c | 4 ++++
block/iscsi.c | 65 +++++++++++++++++++++++++++++++++++++++++++++------------
2 files changed, 56 insertions(+), 13 deletions(-)
diff --git a/block.c b/block.c
index 50dab8e..d8880e3 100644
--- a/block.c
+++ b/block.c
@@ -2427,6 +2427,10 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
return -EACCES;
if (bdrv_in_use(bs))
return -EBUSY;
+
+ /* there should be better no AIOs in flight when we truncate the device */
+ bdrv_drain_all();
+
ret = drv->bdrv_truncate(bs, offset);
if (ret == 0) {
ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
diff --git a/block/iscsi.c b/block/iscsi.c
index deb3b68..dd41943 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;
@@ -926,23 +954,13 @@ 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;
+ if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) {
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);
@@ -1023,6 +1041,26 @@ 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 +1131,7 @@ 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
