Il 15/02/2013 15:35, Peter Lieven ha scritto:
> 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().
Please move the entire switch statement of iscsi_open, the code should
be cleaner. Also please separate bdrv_drain_all() to a separate patch
and Cc qemu-stable on that one (Kevin's message should provide a good
skeleton for a commit messages).
Paolo
> 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,
