[Qemu-devel] [PATCH for-2.4 V2 0/9] various improvements for the iSCSI driver

[Qemu-devel] [PATCH for-2.4 V2 0/9] various improvements for the iSCSI driver

[Peter Lieven]

v1->v2: - removed the requirement for libiscsi 1.10.0 [Paolo]
        - reworked to force_next_flush logic [Paolo]

Peter Lieven (9):
  block/iscsi: do not forget to logout from target
  block/iscsi: change all iscsilun properties from uint8_t to bool
  block/iscsi: rename iscsi_write_protected and let it return void
  block/iscsi: store DPOFUA bit from the modesense command
  block/iscsi: optimize WRITE10/16 if cache.writeback is not set
  block/iscsi: increase retry count
  block/iscsi: handle SCSI_STATUS_TASK_SET_FULL
  block/iscsi: bump year in copyright notice
  block/iscsi: use the allocationmap also if cache.direct=on

 block/iscsi.c | 64 ++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 20 deletions(-)

-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 1/9] block/iscsi: do not forget to logout from target

[Peter Lieven]

We actually were always impolitely dropping the connection and
not cleanly logging out.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/iscsi.c b/block/iscsi.c
index ba33290..be8af46 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1501,6 +1501,9 @@ out:
 
     if (ret) {
         if (iscsi != NULL) {
+            if (iscsi_is_logged_in(iscsi)) {
+                iscsi_logout_sync(iscsi);
+            }
             iscsi_destroy_context(iscsi);
         }
         memset(iscsilun, 0, sizeof(IscsiLun));
@@ -1514,6 +1517,9 @@ static void iscsi_close(BlockDriverState *bs)
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
     iscsi_detach_aio_context(bs);
+    if (iscsi_is_logged_in(iscsi)) {
+        iscsi_logout_sync(iscsi);
+    }
     iscsi_destroy_context(iscsi);
     g_free(iscsilun->zeroblock);
     g_free(iscsilun->allocationmap);
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 2/9] block/iscsi: change all iscsilun properties from uint8_t to bool

[Peter Lieven]

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index be8af46..6cf7e99 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -57,9 +57,6 @@ typedef struct IscsiLun {
     int events;
     QEMUTimer *nop_timer;
     QEMUTimer *event_timer;
-    uint8_t lbpme;
-    uint8_t lbprz;
-    uint8_t has_write_same;
     struct scsi_inquiry_logical_block_provisioning lbp;
     struct scsi_inquiry_block_limits bl;
     unsigned char *zeroblock;
@@ -67,6 +64,9 @@ typedef struct IscsiLun {
     int cluster_sectors;
     bool use_16_for_rw;
     bool write_protected;
+    bool lbpme;
+    bool lbprz;
+    bool has_write_same;
 } IscsiLun;
 
 typedef struct IscsiTask {
@@ -460,7 +460,7 @@ static int64_t coroutine_fn iscsi_co_get_block_status(BlockDriverState *bs,
     *pnum = nb_sectors;
 
     /* LUN does not support logical block provisioning */
-    if (iscsilun->lbpme == 0) {
+    if (!iscsilun->lbpme) {
         goto out;
     }
 
@@ -1121,8 +1121,8 @@ static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
                 } else {
                     iscsilun->block_size = rc16->block_length;
                     iscsilun->num_blocks = rc16->returned_lba + 1;
-                    iscsilun->lbpme = rc16->lbpme;
-                    iscsilun->lbprz = rc16->lbprz;
+                    iscsilun->lbpme = !!rc16->lbpme;
+                    iscsilun->lbprz = !!rc16->lbprz;
                     iscsilun->use_16_for_rw = (rc16->returned_lba > 0xffffffff);
                 }
             }
@@ -1655,7 +1655,7 @@ out:
 static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     IscsiLun *iscsilun = bs->opaque;
-    bdi->unallocated_blocks_are_zero = !!iscsilun->lbprz;
+    bdi->unallocated_blocks_are_zero = iscsilun->lbprz;
     bdi->can_write_zeroes_with_unmap = iscsilun->lbprz && iscsilun->lbp.lbpws;
     bdi->cluster_size = iscsilun->cluster_sectors * BDRV_SECTOR_SIZE;
     return 0;
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 3/9] block/iscsi: rename iscsi_write_protected and let it return void

[Peter Lieven]

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 6cf7e99..221c9fc 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1253,11 +1253,11 @@ static void iscsi_attach_aio_context(BlockDriverState *bs,
                                           iscsi_timed_set_events, iscsilun);
 }
 
-static bool iscsi_is_write_protected(IscsiLun *iscsilun)
+static void iscsi_modesense_sync(IscsiLun *iscsilun)
 {
     struct scsi_task *task;
     struct scsi_mode_sense *ms = NULL;
-    bool wrprotected = false;
+    iscsilun->write_protected = false;
 
     task = iscsi_modesense6_sync(iscsilun->iscsi, iscsilun->lun,
                                  1, SCSI_MODESENSE_PC_CURRENT,
@@ -1278,13 +1278,12 @@ static bool iscsi_is_write_protected(IscsiLun *iscsilun)
                      iscsi_get_error(iscsilun->iscsi));
         goto out;
     }
-    wrprotected = ms->device_specific_parameter & 0x80;
+    iscsilun->write_protected = ms->device_specific_parameter & 0x80;
 
 out:
     if (task) {
         scsi_free_scsi_task(task);
     }
-    return wrprotected;
 }
 
 /*
@@ -1403,7 +1402,8 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     scsi_free_scsi_task(task);
     task = NULL;
 
-    iscsilun->write_protected = iscsi_is_write_protected(iscsilun);
+    iscsi_modesense_sync(iscsilun);
+
     /* Check the write protect flag of the LUN if we want to write */
     if (iscsilun->type == TYPE_DISK && (flags & BDRV_O_RDWR) &&
         iscsilun->write_protected) {
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 4/9] block/iscsi: store DPOFUA bit from the modesense command

[Peter Lieven]

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/iscsi.c b/block/iscsi.c
index 221c9fc..237faa1 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -66,6 +66,7 @@ typedef struct IscsiLun {
     bool write_protected;
     bool lbpme;
     bool lbprz;
+    bool dpofua;
     bool has_write_same;
 } IscsiLun;
 
@@ -1258,6 +1259,7 @@ static void iscsi_modesense_sync(IscsiLun *iscsilun)
     struct scsi_task *task;
     struct scsi_mode_sense *ms = NULL;
     iscsilun->write_protected = false;
+    iscsilun->dpofua = false;
 
     task = iscsi_modesense6_sync(iscsilun->iscsi, iscsilun->lun,
                                  1, SCSI_MODESENSE_PC_CURRENT,
@@ -1279,6 +1281,7 @@ static void iscsi_modesense_sync(IscsiLun *iscsilun)
         goto out;
     }
     iscsilun->write_protected = ms->device_specific_parameter & 0x80;
+    iscsilun->dpofua          = ms->device_specific_parameter & 0x10;
 
 out:
     if (task) {
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 5/9] block/iscsi: optimize WRITE10/16 if cache.writeback is not set

[Peter Lieven]

SCSI allowes to tell the target to not return from a write command
if the date is not written to the disk. Use this so called FUA
bit if it is supported to optimize WRITE commands if writeback is
not allowed.

In this case qemu always issues a WRITE followed by a FLUSH. This
is 2 round trip times. If we set the FUA bit we can ignore the
following FLUSH.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 237faa1..6033330 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -68,6 +68,7 @@ typedef struct IscsiLun {
     bool lbprz;
     bool dpofua;
     bool has_write_same;
+    bool force_next_flush;
 } IscsiLun;
 
 typedef struct IscsiTask {
@@ -80,6 +81,7 @@ typedef struct IscsiTask {
     QEMUBH *bh;
     IscsiLun *iscsilun;
     QEMUTimer retry_timer;
+    bool force_next_flush;
 } IscsiTask;
 
 typedef struct IscsiAIOCB {
@@ -200,6 +202,8 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
             }
         }
         error_report("iSCSI Failure: %s", iscsi_get_error(iscsi));
+    } else {
+        iTask->iscsilun->force_next_flush |= iTask->force_next_flush;
     }
 
 out:
@@ -370,6 +374,7 @@ static int coroutine_fn iscsi_co_writev(BlockDriverState *bs,
     struct IscsiTask iTask;
     uint64_t lba;
     uint32_t num_sectors;
+    int fua;
 
     if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
         return -EINVAL;
@@ -385,15 +390,17 @@ static int coroutine_fn iscsi_co_writev(BlockDriverState *bs,
     num_sectors = sector_qemu2lun(nb_sectors, iscsilun);
     iscsi_co_init_iscsitask(iscsilun, &iTask);
 retry:
+    fua = iscsilun->dpofua && !bs->enable_write_cache;
+    iTask.force_next_flush = !fua;
     if (iscsilun->use_16_for_rw) {
         iTask.task = iscsi_write16_task(iscsilun->iscsi, iscsilun->lun, lba,
                                         NULL, num_sectors * iscsilun->block_size,
-                                        iscsilun->block_size, 0, 0, 0, 0, 0,
+                                        iscsilun->block_size, 0, 0, fua, 0, 0,
                                         iscsi_co_generic_cb, &iTask);
     } else {
         iTask.task = iscsi_write10_task(iscsilun->iscsi, iscsilun->lun, lba,
                                         NULL, num_sectors * iscsilun->block_size,
-                                        iscsilun->block_size, 0, 0, 0, 0, 0,
+                                        iscsilun->block_size, 0, 0, fua, 0, 0,
                                         iscsi_co_generic_cb, &iTask);
     }
     if (iTask.task == NULL) {
@@ -621,8 +628,12 @@ static int coroutine_fn iscsi_co_flush(BlockDriverState *bs)
         return 0;
     }
 
-    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    if (!iscsilun->force_next_flush) {
+        return 0;
+    }
+    iscsilun->force_next_flush = false;
 
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
 retry:
     if (iscsi_synchronizecache10_task(iscsilun->iscsi, iscsilun->lun, 0, 0, 0,
                                       0, iscsi_co_generic_cb, &iTask) == NULL) {
@@ -918,6 +929,7 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState *bs, int64_t sector_num,
     }
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
+    iTask.force_next_flush = true;
 retry:
     if (use_16_for_ws) {
         iTask.task = iscsi_writesame16_task(iscsilun->iscsi, iscsilun->lun, lba,
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 6/9] block/iscsi: increase retry count

[Peter Lieven]

The idea is that a command is retried in a BUSY condition
up a time of approx. 60 seconds before it is failed. This should
be far higher than any command timeout in the guest.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 6033330..5999f74 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -103,7 +103,7 @@ typedef struct IscsiAIOCB {
 #define NOP_INTERVAL 5000
 #define MAX_NOP_FAILURES 3
 #define ISCSI_CMD_RETRIES ARRAY_SIZE(iscsi_retry_times)
-static const unsigned iscsi_retry_times[] = {8, 32, 128, 512, 2048};
+static const unsigned iscsi_retry_times[] = {8, 32, 128, 512, 2048, 8192, 32768};
 
 /* this threshold is a trade-off knob to choose between
  * the potential additional overhead of an extra GET_LBA_STATUS request
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 7/9] block/iscsi: handle SCSI_STATUS_TASK_SET_FULL

[Peter Lieven]

a target may issue a SCSI_STATUS_TASK_SET_FULL status
if there is more than one "BUSY" command queued already.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 5999f74..328907b 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -186,10 +186,13 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
                 iTask->do_retry = 1;
                 goto out;
             }
-            if (status == SCSI_STATUS_BUSY) {
+            /* status 0x28 is SCSI_TASK_SET_FULL. It was first introduced
+             * in libiscsi 1.10.0. Hardcode this value here to avoid
+             * the need to bump the libiscsi requirement to 1.10.0 */
+            if (status == SCSI_STATUS_BUSY || status == 0x28) {
                 unsigned retry_time =
                     exp_random(iscsi_retry_times[iTask->retries - 1]);
-                error_report("iSCSI Busy (retry #%u in %u ms): %s",
+                error_report("iSCSI Busy/TaskSetFull (retry #%u in %u ms): %s",
                              iTask->retries, retry_time,
                              iscsi_get_error(iscsi));
                 aio_timer_init(iTask->iscsilun->aio_context,
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 8/9] block/iscsi: bump year in copyright notice

[Peter Lieven]

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 328907b..8364f97 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2,7 +2,7 @@
  * QEMU Block driver for iSCSI images
  *
  * Copyright (c) 2010-2011 Ronnie Sahlberg <ronniesahlberg@gmail.com>
- * Copyright (c) 2012-2014 Peter Lieven <pl@kamp.de>
+ * Copyright (c) 2012-2015 Peter Lieven <pl@kamp.de>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
-- 
1.9.1

[Qemu-devel] [PATCH for-2.4 V2 9/9] block/iscsi: use the allocationmap also if cache.direct=on

[Peter Lieven]

the allocationmap has only a hint character. The driver always
double checks that blocks marked unallocated in the cache are
still unallocated before taking the fast path and return zeroes.
So using the allocationmap is migration safe and can
also be enabled with cache.direct=on.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 8364f97..8fca1d3 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1499,7 +1499,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
         iscsilun->bl.opt_unmap_gran * iscsilun->block_size <= 16 * 1024 * 1024) {
         iscsilun->cluster_sectors = (iscsilun->bl.opt_unmap_gran *
                                      iscsilun->block_size) >> BDRV_SECTOR_BITS;
-        if (iscsilun->lbprz && !(bs->open_flags & BDRV_O_NOCACHE)) {
+        if (iscsilun->lbprz) {
             iscsilun->allocationmap = iscsi_allocationmap_init(iscsilun);
             if (iscsilun->allocationmap == NULL) {
                 ret = -ENOMEM;
-- 
1.9.1

Re: [Qemu-devel] [Qemu-block] [PATCH for-2.4 V2 0/9] various improvements for the iSCSI driver

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 1009 bytes --]

On Thu, Apr 16, 2015 at 04:08:24PM +0200, Peter Lieven wrote:
> v1->v2: - removed the requirement for libiscsi 1.10.0 [Paolo]
>         - reworked to force_next_flush logic [Paolo]
> 
> Peter Lieven (9):
>   block/iscsi: do not forget to logout from target
>   block/iscsi: change all iscsilun properties from uint8_t to bool
>   block/iscsi: rename iscsi_write_protected and let it return void
>   block/iscsi: store DPOFUA bit from the modesense command
>   block/iscsi: optimize WRITE10/16 if cache.writeback is not set
>   block/iscsi: increase retry count
>   block/iscsi: handle SCSI_STATUS_TASK_SET_FULL
>   block/iscsi: bump year in copyright notice
>   block/iscsi: use the allocationmap also if cache.direct=on
> 
>  block/iscsi.c | 64 ++++++++++++++++++++++++++++++++++++++++-------------------
>  1 file changed, 44 insertions(+), 20 deletions(-)
> 
> -- 
> 1.9.1
> 
> 

Thanks, applied to my block-next tree:
https://github.com/stefanha/qemu/commits/block-next

Stefan

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