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iscsi: split discard requests in multiple parts

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Replace .bdrv_aio_discard with .bdrv_co_discard so that discard
requests can be split in multiple parts, each for a small amount
of sectors.

This is useful because we expose a generic API with no limit
on the amount of sectors that can be unmapped in one request.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Lieven 2013-07-19 09:19:41 +02:00 committed by Paolo Bonzini
parent 54a5c1d5db
commit 65f3e33964
1 changed files with 73 additions and 83 deletions
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156
block/iscsi.c
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@ -87,6 +87,7 @@ typedef struct IscsiAIOCB {
#define NOP_INTERVAL 5000
#define MAX_NOP_FAILURES 3
#define ISCSI_CMD_RETRIES 5
#define ISCSI_MAX_UNMAP 131072
static void
iscsi_bh_cb(void *p)
@ -618,88 +619,6 @@ iscsi_aio_flush(BlockDriverState *bs,
return &acb->common;
}
static int iscsi_aio_discard_acb(IscsiAIOCB *acb);
static void
iscsi_unmap_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *opaque)
{
IscsiAIOCB *acb = opaque;
if (acb->canceled != 0) {
return;
}
acb->status = 0;
if (status != 0) {
if (status == SCSI_STATUS_CHECK_CONDITION
&& acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
&& acb->retries-- > 0) {
scsi_free_scsi_task(acb->task);
acb->task = NULL;
if (iscsi_aio_discard_acb(acb) == 0) {
iscsi_set_events(acb->iscsilun);
return;
}
}
error_report("Failed to unmap data on iSCSI lun. %s",
iscsi_get_error(iscsi));
acb->status = -EIO;
}
iscsi_schedule_bh(acb);
}
static int iscsi_aio_discard_acb(IscsiAIOCB *acb) {
struct iscsi_context *iscsi = acb->iscsilun->iscsi;
struct unmap_list list[1];
acb->canceled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
acb->buf = NULL;
list[0].lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);
list[0].num = acb->nb_sectors * BDRV_SECTOR_SIZE / acb->iscsilun->block_size;
acb->task = iscsi_unmap_task(iscsi, acb->iscsilun->lun,
0, 0, &list[0], 1,
iscsi_unmap_cb,
acb);
if (acb->task == NULL) {
error_report("iSCSI: Failed to send unmap command. %s",
iscsi_get_error(iscsi));
return -1;
}
return 0;
}
static BlockDriverAIOCB *
iscsi_aio_discard(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
IscsiLun *iscsilun = bs->opaque;
IscsiAIOCB *acb;
acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
acb->iscsilun = iscsilun;
acb->nb_sectors = nb_sectors;
acb->sector_num = sector_num;
acb->retries = ISCSI_CMD_RETRIES;
if (iscsi_aio_discard_acb(acb) != 0) {
qemu_aio_release(acb);
return NULL;
}
iscsi_set_events(iscsilun);
return &acb->common;
}
#ifdef __linux__
static void
iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
@ -982,6 +901,77 @@ out:
return ret;
}
static int
coroutine_fn iscsi_co_discard(BlockDriverState *bs, int64_t sector_num,
int nb_sectors)
{
IscsiLun *iscsilun = bs->opaque;
struct IscsiTask iTask;
struct unmap_list list;
uint32_t nb_blocks;
uint32_t max_unmap;
if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
return -EINVAL;
}
if (!iscsilun->lbp.lbpu) {
/* UNMAP is not supported by the target */
return 0;
}
list.lba = sector_qemu2lun(sector_num, iscsilun);
nb_blocks = sector_qemu2lun(nb_sectors, iscsilun);
max_unmap = iscsilun->bl.max_unmap;
if (max_unmap == 0xffffffff) {
max_unmap = ISCSI_MAX_UNMAP;
}
while (nb_blocks > 0) {
iscsi_co_init_iscsitask(iscsilun, &iTask);
list.num = nb_blocks;
if (list.num > max_unmap) {
list.num = max_unmap;
}
retry:
if (iscsi_unmap_task(iscsilun->iscsi, iscsilun->lun, 0, 0, &list, 1,
iscsi_co_generic_cb, &iTask) == NULL) {
return -EIO;
}
while (!iTask.complete) {
iscsi_set_events(iscsilun);
qemu_coroutine_yield();
}
if (iTask.task != NULL) {
scsi_free_scsi_task(iTask.task);
iTask.task = NULL;
}
if (iTask.do_retry) {
goto retry;
}
if (iTask.status == SCSI_STATUS_CHECK_CONDITION) {
/* the target might fail with a check condition if it
is not happy with the alignment of the UNMAP request
we silently fail in this case */
return 0;
}
if (iTask.status != SCSI_STATUS_GOOD) {
return -EIO;
}
list.lba += list.num;
nb_blocks -= list.num;
}
return 0;
}
static int parse_chap(struct iscsi_context *iscsi, const char *target)
{
QemuOptsList *list;
@ -1533,12 +1523,12 @@ static BlockDriver bdrv_iscsi = {
.bdrv_truncate = iscsi_truncate,
.bdrv_co_get_block_status = iscsi_co_get_block_status,
.bdrv_co_discard = iscsi_co_discard,
.bdrv_aio_readv = iscsi_aio_readv,
.bdrv_aio_writev = iscsi_aio_writev,
.bdrv_aio_flush = iscsi_aio_flush,
.bdrv_aio_discard = iscsi_aio_discard,
.bdrv_has_zero_init = iscsi_has_zero_init,
#ifdef __linux__