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[Qemu-devel] [PATCH 1/6] iscsi: retry read, write, flush and unmap on un
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From: |
Paolo Bonzini |
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Subject: |
[Qemu-devel] [PATCH 1/6] iscsi: retry read, write, flush and unmap on unit attention check conditions |
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Date: |
Tue, 5 Mar 2013 18:05:20 +0100 |
From: Peter Lieven <address@hidden>
the storage might return a check condition status for various reasons.
(e.g. bus reset, capacity change, thin-provisioning info etc.)
currently all these informative status responses lead to an I/O error
which is populated to the guest. this patch introduces a retry mechanism
to avoid this.
Signed-off-by: Peter Lieven <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/iscsi.c | 291 ++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 203 insertions(+), 88 deletions(-)
diff --git a/block/iscsi.c b/block/iscsi.c
index deb3b68..439af6f 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -60,8 +60,11 @@ typedef struct IscsiAIOCB {
uint8_t *buf;
int status;
int canceled;
+ int retries;
size_t read_size;
size_t read_offset;
+ int64_t sector_num;
+ int nb_sectors;
#ifdef __linux__
sg_io_hdr_t *ioh;
#endif
@@ -69,6 +72,7 @@ typedef struct IscsiAIOCB {
#define NOP_INTERVAL 5000
#define MAX_NOP_FAILURES 3
+#define ISCSI_CMD_RETRIES 5
static void
iscsi_bh_cb(void *p)
@@ -191,6 +195,8 @@ iscsi_process_write(void *arg)
iscsi_set_events(iscsilun);
}
+static int
+iscsi_aio_writev_acb(IscsiAIOCB *acb);
static void
iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status,
@@ -208,7 +214,19 @@ iscsi_aio_write16_cb(struct iscsi_context *iscsi, int
status,
}
acb->status = 0;
- if (status < 0) {
+ if (status != 0) {
+ if (status == SCSI_STATUS_CHECK_CONDITION
+ && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
+ && acb->retries-- > 0) {
+ if (acb->task != NULL) {
+ scsi_free_scsi_task(acb->task);
+ acb->task = NULL;
+ }
+ if (iscsi_aio_writev_acb(acb) == 0) {
+ iscsi_set_events(acb->iscsilun);
+ return;
+ }
+ }
error_report("Failed to write16 data to iSCSI lun. %s",
iscsi_get_error(iscsi));
acb->status = -EIO;
@@ -222,15 +240,10 @@ static int64_t sector_qemu2lun(int64_t sector, IscsiLun
*iscsilun)
return sector * BDRV_SECTOR_SIZE / iscsilun->block_size;
}
-static BlockDriverAIOCB *
-iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
- QEMUIOVector *qiov, int nb_sectors,
- BlockDriverCompletionFunc *cb,
- void *opaque)
+static int
+iscsi_aio_writev_acb(IscsiAIOCB *acb)
{
- IscsiLun *iscsilun = bs->opaque;
- struct iscsi_context *iscsi = iscsilun->iscsi;
- IscsiAIOCB *acb;
+ struct iscsi_context *iscsi = acb->iscsilun->iscsi;
size_t size;
uint32_t num_sectors;
uint64_t lba;
@@ -239,19 +252,13 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
#endif
int ret;
- acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
- trace_iscsi_aio_writev(iscsi, sector_num, nb_sectors, opaque, acb);
-
- acb->iscsilun = iscsilun;
- acb->qiov = qiov;
-
acb->canceled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
acb->buf = NULL;
/* this will allow us to get rid of 'buf' completely */
- size = nb_sectors * BDRV_SECTOR_SIZE;
+ size = acb->nb_sectors * BDRV_SECTOR_SIZE;
#if !defined(LIBISCSI_FEATURE_IOVECTOR)
data.size = MIN(size, acb->qiov->size);
@@ -270,48 +277,76 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
if (acb->task == NULL) {
error_report("iSCSI: Failed to allocate task for scsi WRITE16 "
"command. %s", iscsi_get_error(iscsi));
- qemu_aio_release(acb);
- return NULL;
+ return -1;
}
memset(acb->task, 0, sizeof(struct scsi_task));
acb->task->xfer_dir = SCSI_XFER_WRITE;
acb->task->cdb_size = 16;
acb->task->cdb[0] = 0x8a;
- lba = sector_qemu2lun(sector_num, iscsilun);
+ lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);
*(uint32_t *)&acb->task->cdb[2] = htonl(lba >> 32);
*(uint32_t *)&acb->task->cdb[6] = htonl(lba & 0xffffffff);
- num_sectors = size / iscsilun->block_size;
+ num_sectors = size / acb->iscsilun->block_size;
*(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);
acb->task->expxferlen = size;
#if defined(LIBISCSI_FEATURE_IOVECTOR)
- ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,
iscsi_aio_write16_cb,
NULL,
acb);
#else
- ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,
iscsi_aio_write16_cb,
&data,
acb);
#endif
if (ret != 0) {
- scsi_free_scsi_task(acb->task);
g_free(acb->buf);
- qemu_aio_release(acb);
- return NULL;
+ return -1;
}
#if defined(LIBISCSI_FEATURE_IOVECTOR)
scsi_task_set_iov_out(acb->task, (struct scsi_iovec*) acb->qiov->iov,
acb->qiov->niov);
#endif
- iscsi_set_events(iscsilun);
+ return 0;
+}
+
+static BlockDriverAIOCB *
+iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *qiov, int nb_sectors,
+ BlockDriverCompletionFunc *cb,
+ void *opaque)
+{
+ IscsiLun *iscsilun = bs->opaque;
+ IscsiAIOCB *acb;
+
+ acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
+ trace_iscsi_aio_writev(iscsilun->iscsi, sector_num, nb_sectors, opaque,
acb);
+
+ acb->iscsilun = iscsilun;
+ acb->qiov = qiov;
+ acb->nb_sectors = nb_sectors;
+ acb->sector_num = sector_num;
+ acb->retries = ISCSI_CMD_RETRIES;
+
+ if (iscsi_aio_writev_acb(acb) != 0) {
+ if (acb->task) {
+ scsi_free_scsi_task(acb->task);
+ }
+ qemu_aio_release(acb);
+ return NULL;
+ }
+ iscsi_set_events(iscsilun);
return &acb->common;
}
+static int
+iscsi_aio_readv_acb(IscsiAIOCB *acb);
+
static void
iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *opaque)
@@ -326,6 +361,18 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int
status,
acb->status = 0;
if (status != 0) {
+ if (status == SCSI_STATUS_CHECK_CONDITION
+ && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
+ && acb->retries-- > 0) {
+ if (acb->task != NULL) {
+ scsi_free_scsi_task(acb->task);
+ acb->task = NULL;
+ }
+ if (iscsi_aio_readv_acb(acb) == 0) {
+ iscsi_set_events(acb->iscsilun);
+ return;
+ }
+ }
error_report("Failed to read16 data from iSCSI lun. %s",
iscsi_get_error(iscsi));
acb->status = -EIO;
@@ -334,35 +381,20 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int
status,
iscsi_schedule_bh(acb);
}
-static BlockDriverAIOCB *
-iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
- QEMUIOVector *qiov, int nb_sectors,
- BlockDriverCompletionFunc *cb,
- void *opaque)
+static int
+iscsi_aio_readv_acb(IscsiAIOCB *acb)
{
- IscsiLun *iscsilun = bs->opaque;
- struct iscsi_context *iscsi = iscsilun->iscsi;
- IscsiAIOCB *acb;
- size_t qemu_read_size;
+ struct iscsi_context *iscsi = acb->iscsilun->iscsi;
+ uint64_t lba;
+ uint32_t num_sectors;
+ int ret;
#if !defined(LIBISCSI_FEATURE_IOVECTOR)
int i;
#endif
- int ret;
- uint64_t lba;
- uint32_t num_sectors;
-
- qemu_read_size = BDRV_SECTOR_SIZE * (size_t)nb_sectors;
-
- acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
- trace_iscsi_aio_readv(iscsi, sector_num, nb_sectors, opaque, acb);
-
- acb->iscsilun = iscsilun;
- acb->qiov = qiov;
acb->canceled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
- acb->read_size = qemu_read_size;
acb->buf = NULL;
/* If LUN blocksize is bigger than BDRV_BLOCK_SIZE a read from QEMU
@@ -370,30 +402,29 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
* data.
*/
acb->read_offset = 0;
- if (iscsilun->block_size > BDRV_SECTOR_SIZE) {
- uint64_t bdrv_offset = BDRV_SECTOR_SIZE * sector_num;
+ if (acb->iscsilun->block_size > BDRV_SECTOR_SIZE) {
+ uint64_t bdrv_offset = BDRV_SECTOR_SIZE * acb->sector_num;
- acb->read_offset = bdrv_offset % iscsilun->block_size;
+ acb->read_offset = bdrv_offset % acb->iscsilun->block_size;
}
- num_sectors = (qemu_read_size + iscsilun->block_size
+ num_sectors = (acb->read_size + acb->iscsilun->block_size
+ acb->read_offset - 1)
- / iscsilun->block_size;
+ / acb->iscsilun->block_size;
acb->task = malloc(sizeof(struct scsi_task));
if (acb->task == NULL) {
error_report("iSCSI: Failed to allocate task for scsi READ16 "
"command. %s", iscsi_get_error(iscsi));
- qemu_aio_release(acb);
- return NULL;
+ return -1;
}
memset(acb->task, 0, sizeof(struct scsi_task));
acb->task->xfer_dir = SCSI_XFER_READ;
- lba = sector_qemu2lun(sector_num, iscsilun);
- acb->task->expxferlen = qemu_read_size;
+ lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);
+ acb->task->expxferlen = acb->read_size;
- switch (iscsilun->type) {
+ switch (acb->iscsilun->type) {
case TYPE_DISK:
acb->task->cdb_size = 16;
acb->task->cdb[0] = 0x88;
@@ -409,14 +440,12 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
break;
}
- ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,
iscsi_aio_read16_cb,
NULL,
acb);
if (ret != 0) {
- scsi_free_scsi_task(acb->task);
- qemu_aio_release(acb);
- return NULL;
+ return -1;
}
#if defined(LIBISCSI_FEATURE_IOVECTOR)
@@ -428,12 +457,42 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
acb->qiov->iov[i].iov_base);
}
#endif
+ return 0;
+}
- iscsi_set_events(iscsilun);
+static BlockDriverAIOCB *
+iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *qiov, int nb_sectors,
+ BlockDriverCompletionFunc *cb,
+ void *opaque)
+{
+ IscsiLun *iscsilun = bs->opaque;
+ IscsiAIOCB *acb;
+ acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
+ trace_iscsi_aio_readv(iscsilun->iscsi, sector_num, nb_sectors, opaque,
acb);
+
+ acb->nb_sectors = nb_sectors;
+ acb->sector_num = sector_num;
+ acb->iscsilun = iscsilun;
+ acb->qiov = qiov;
+ acb->read_size = BDRV_SECTOR_SIZE * (size_t)acb->nb_sectors;
+ acb->retries = ISCSI_CMD_RETRIES;
+
+ if (iscsi_aio_readv_acb(acb) != 0) {
+ if (acb->task) {
+ scsi_free_scsi_task(acb->task);
+ }
+ qemu_aio_release(acb);
+ return NULL;
+ }
+
+ iscsi_set_events(iscsilun);
return &acb->common;
}
+static int
+iscsi_aio_flush_acb(IscsiAIOCB *acb);
static void
iscsi_synccache10_cb(struct iscsi_context *iscsi, int status,
@@ -446,7 +505,19 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int
status,
}
acb->status = 0;
- if (status < 0) {
+ if (status != 0) {
+ if (status == SCSI_STATUS_CHECK_CONDITION
+ && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
+ && acb->retries-- > 0) {
+ if (acb->task != NULL) {
+ scsi_free_scsi_task(acb->task);
+ acb->task = NULL;
+ }
+ if (iscsi_aio_flush_acb(acb) == 0) {
+ iscsi_set_events(acb->iscsilun);
+ return;
+ }
+ }
error_report("Failed to sync10 data on iSCSI lun. %s",
iscsi_get_error(iscsi));
acb->status = -EIO;
@@ -455,29 +526,43 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int
status,
iscsi_schedule_bh(acb);
}
-static BlockDriverAIOCB *
-iscsi_aio_flush(BlockDriverState *bs,
- BlockDriverCompletionFunc *cb, void *opaque)
+static int
+iscsi_aio_flush_acb(IscsiAIOCB *acb)
{
- IscsiLun *iscsilun = bs->opaque;
- struct iscsi_context *iscsi = iscsilun->iscsi;
- IscsiAIOCB *acb;
-
- acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
+ struct iscsi_context *iscsi = acb->iscsilun->iscsi;
- acb->iscsilun = iscsilun;
acb->canceled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
acb->buf = NULL;
- acb->task = iscsi_synchronizecache10_task(iscsi, iscsilun->lun,
+ acb->task = iscsi_synchronizecache10_task(iscsi, acb->iscsilun->lun,
0, 0, 0, 0,
iscsi_synccache10_cb,
acb);
if (acb->task == NULL) {
error_report("iSCSI: Failed to send synchronizecache10 command. %s",
iscsi_get_error(iscsi));
+ return -1;
+ }
+
+ return 0;
+}
+
+static BlockDriverAIOCB *
+iscsi_aio_flush(BlockDriverState *bs,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ IscsiLun *iscsilun = bs->opaque;
+
+ IscsiAIOCB *acb;
+
+ acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
+
+ acb->iscsilun = iscsilun;
+ acb->retries = ISCSI_CMD_RETRIES;
+
+ if (iscsi_aio_flush_acb(acb) != 0) {
qemu_aio_release(acb);
return NULL;
}
@@ -487,6 +572,8 @@ 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)
@@ -498,7 +585,19 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status,
}
acb->status = 0;
- if (status < 0) {
+ if (status != 0) {
+ if (status == SCSI_STATUS_CHECK_CONDITION
+ && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
+ && acb->retries-- > 0) {
+ if (acb->task != NULL) {
+ 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;
@@ -507,34 +606,50 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status,
iscsi_schedule_bh(acb);
}
-static BlockDriverAIOCB *
-iscsi_aio_discard(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors,
- BlockDriverCompletionFunc *cb, void *opaque)
-{
- IscsiLun *iscsilun = bs->opaque;
- struct iscsi_context *iscsi = iscsilun->iscsi;
- IscsiAIOCB *acb;
+static int iscsi_aio_discard_acb(IscsiAIOCB *acb) {
+ struct iscsi_context *iscsi = acb->iscsilun->iscsi;
struct unmap_list list[1];
- acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
-
- acb->iscsilun = iscsilun;
acb->canceled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
acb->buf = NULL;
- list[0].lba = sector_qemu2lun(sector_num, iscsilun);
- list[0].num = nb_sectors * BDRV_SECTOR_SIZE / iscsilun->block_size;
+ 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, iscsilun->lun,
+ 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) {
+ if (acb->task) {
+ scsi_free_scsi_task(acb->task);
+ }
qemu_aio_release(acb);
return NULL;
}
--
1.8.1.2
- [Qemu-devel] [PULL 0/6] SCSI patches for 2013-03-05, Paolo Bonzini, 2013/03/05
- [Qemu-devel] [PATCH 1/6] iscsi: retry read, write, flush and unmap on unit attention check conditions,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 3/6] iscsi: look for pkg-config file too, Paolo Bonzini, 2013/03/05
- [Qemu-devel] [PATCH 4/6] scsi: do not call scsi_read_data/scsi_write_data for a canceled request, Paolo Bonzini, 2013/03/05
- [Qemu-devel] [PATCH 2/6] iscsi: add iscsi_truncate support, Paolo Bonzini, 2013/03/05
- [Qemu-devel] [PATCH 5/6] scsi-disk: do not complete canceled UNMAP requests, Paolo Bonzini, 2013/03/05
- [Qemu-devel] [PATCH 6/6] scsi-disk: handle io_canceled uniformly and correctly, Paolo Bonzini, 2013/03/05