From 36d03c829bbf59e9346784b1e582803c482c4320 Mon Sep 17 00:00:00 2001

Message-Id: <36d03c829bbf59e9346784b1e582803c482c4320.1389014116.git.minovotn@redhat.com>

In-Reply-To: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>

References: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Mon, 9 Dec 2013 14:09:25 +0100

Subject: [PATCH 37/50] scsi-disk: correctly implement WRITE SAME

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <1386598178-11845-40-git-send-email-pbonzini@redhat.com>

Patchwork-id: 56076

O-Subject: [RHEL 7.0 qemu-kvm PATCH 39/52] scsi-disk: correctly implement WRITE SAME

Bugzilla: 1007815

RH-Acked-by: Jeffrey Cody <jcody@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

Fetch the data to be written from the input buffer.  If it is all zeroes,

we can use the write_zeroes call (possibly with the new MAY_UNMAP flag).

Otherwise, do as many write cycles as needed, writing 512k at a time.

Strictly speaking, this is still incorrect because a zero cluster should

only be written if the MAY_UNMAP flag is set.  But this is a bug in qcow2

and the other formats, not in the SCSI code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

(cherry picked from commit 84f94a9a82487639bc87d5f09f938c9f6a61f79a)

---

 hw/scsi/scsi-disk.c | 140 +++++++++++++++++++++++++++++++++++++++++++---------

 1 file changed, 116 insertions(+), 24 deletions(-)

Signed-off-by: Michal Novotny <minovotn@redhat.com>

---

 hw/scsi/scsi-disk.c | 140 +++++++++++++++++++++++++++++++++++++++++++---------

 1 file changed, 116 insertions(+), 24 deletions(-)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c

index 0640bb0..efadfc0 100644

--- a/hw/scsi/scsi-disk.c

+++ b/hw/scsi/scsi-disk.c

@@ -41,6 +41,7 @@ do { printf("scsi-disk: " fmt , ## __VA_ARGS__); } while (0)

 #include <scsi/sg.h>

 #endif

+#define SCSI_WRITE_SAME_MAX         524288

 #define SCSI_DMA_BUF_SIZE           131072

 #define SCSI_MAX_INQUIRY_LEN        256

 #define SCSI_MAX_MODE_LEN           256

@@ -634,6 +635,8 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)

             buflen = 0x40;

             memset(outbuf + 4, 0, buflen - 4);

+            outbuf[4] = 0x1; /* wsnz */

+

             /* optimal transfer length granularity */

             outbuf[6] = (min_io_size >> 8) & 0xff;

             outbuf[7] = min_io_size & 0xff;

@@ -1589,6 +1592,111 @@ invalid_field:

     scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));

 }

+typedef struct WriteSameCBData {

+    SCSIDiskReq *r;

+    int64_t sector;

+    int nb_sectors;

+    QEMUIOVector qiov;

+    struct iovec iov;

+} WriteSameCBData;

+

+static void scsi_write_same_complete(void *opaque, int ret)

+{

+    WriteSameCBData *data = opaque;

+    SCSIDiskReq *r = data->r;

+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);

+

+    assert(r->req.aiocb != NULL);

+    r->req.aiocb = NULL;

+    bdrv_acct_done(s->qdev.conf.bs, &r->acct);

+    if (r->req.io_canceled) {

+        goto done;

+    }

+

+    if (ret < 0) {

+        if (scsi_handle_rw_error(r, -ret)) {

+            goto done;

+        }

+    }

+

+    data->nb_sectors -= data->iov.iov_len / 512;

+    data->sector += data->iov.iov_len / 512;

+    data->iov.iov_len = MIN(data->nb_sectors * 512, data->iov.iov_len);

+    if (data->iov.iov_len) {

+        bdrv_acct_start(s->qdev.conf.bs, &r->acct, data->iov.iov_len, BDRV_ACCT_WRITE);

+        r->req.aiocb = bdrv_aio_writev(s->qdev.conf.bs, data->sector,

+                                       &data->qiov, data->iov.iov_len / 512,

+                                       scsi_write_same_complete, r);

+        return;

+    }

+

+    scsi_req_complete(&r->req, GOOD);

+

+done:

+    if (!r->req.io_canceled) {

+        scsi_req_unref(&r->req);

+    }

+    qemu_vfree(data->iov.iov_base);

+    g_free(data);

+}

+

+static void scsi_disk_emulate_write_same(SCSIDiskReq *r, uint8_t *inbuf)

+{

+    SCSIRequest *req = &r->req;

+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev);

+    uint32_t nb_sectors = scsi_data_cdb_length(r->req.cmd.buf);

+    WriteSameCBData *data;

+    uint8_t *buf;

+    int i;

+

+    /* Fail if PBDATA=1 or LBDATA=1 or ANCHOR=1.  */

+    if (nb_sectors == 0 || (req->cmd.buf[1] & 0x16)) {

+        scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));

+        return;

+    }

+

+    if (bdrv_is_read_only(s->qdev.conf.bs)) {

+        scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));

+        return;

+    }

+    if (!check_lba_range(s, r->req.cmd.lba, nb_sectors)) {

+        scsi_check_condition(r, SENSE_CODE(LBA_OUT_OF_RANGE));

+        return;

+    }

+

+    if (buffer_is_zero(inbuf, s->qdev.blocksize)) {

+        int flags = (req->cmd.buf[1] & 0x8) ? BDRV_REQ_MAY_UNMAP : 0;

+

+        /* The request is used as the AIO opaque value, so add a ref.  */

+        scsi_req_ref(&r->req);

+        bdrv_acct_start(s->qdev.conf.bs, &r->acct, nb_sectors * s->qdev.blocksize,

+                        BDRV_ACCT_WRITE);

+        r->req.aiocb = bdrv_aio_write_zeroes(s->qdev.conf.bs,

+                                             r->req.cmd.lba * (s->qdev.blocksize / 512),

+                                             nb_sectors * (s->qdev.blocksize / 512),

+                                             flags, scsi_aio_complete, r);

+        return;

+    }

+

+    data = g_new0(WriteSameCBData, 1);

+    data->r = r;

+    data->sector = r->req.cmd.lba * (s->qdev.blocksize / 512);

+    data->nb_sectors = nb_sectors * (s->qdev.blocksize / 512);

+    data->iov.iov_len = MIN(data->nb_sectors * 512, SCSI_WRITE_SAME_MAX);

+    data->iov.iov_base = buf = qemu_blockalign(s->qdev.conf.bs, data->iov.iov_len);

+    qemu_iovec_init_external(&data->qiov, &data->iov, 1);

+

+    for (i = 0; i < data->iov.iov_len; i += s->qdev.blocksize) {

+        memcpy(&buf[i], inbuf, s->qdev.blocksize);

+    }

+

+    scsi_req_ref(&r->req);

+    bdrv_acct_start(s->qdev.conf.bs, &r->acct, data->iov.iov_len, BDRV_ACCT_WRITE);

+    r->req.aiocb = bdrv_aio_writev(s->qdev.conf.bs, data->sector,

+                                   &data->qiov, data->iov.iov_len / 512,

+                                   scsi_write_same_complete, data);

+}

+

 static void scsi_disk_emulate_write_data(SCSIRequest *req)

 {

     SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req);

@@ -1612,6 +1720,10 @@ static void scsi_disk_emulate_write_data(SCSIRequest *req)

         scsi_disk_emulate_unmap(r, r->iov.iov_base);

         break;

+    case WRITE_SAME_10:

+    case WRITE_SAME_16:

+        scsi_disk_emulate_write_same(r, r->iov.iov_base);

+        break;

     default:

         abort();

     }

@@ -1854,30 +1966,10 @@ static int32_t scsi_disk_emulate_command(SCSIRequest *req, uint8_t *buf)

         break;

     case WRITE_SAME_10:

     case WRITE_SAME_16:

-        nb_sectors = scsi_data_cdb_length(r->req.cmd.buf);

-        if (bdrv_is_read_only(s->qdev.conf.bs)) {

-            scsi_check_condition(r, SENSE_CODE(WRITE_PROTECTED));

-            return 0;

-        }

-        if (!check_lba_range(s, r->req.cmd.lba, nb_sectors)) {

-            goto illegal_lba;

-        }

-

-        /*

-         * We only support WRITE SAME with the unmap bit set for now.

-         * Reject UNMAP=0 or ANCHOR=1.

-         */

-        if (!(req->cmd.buf[1] & 0x8) || (req->cmd.buf[1] & 0x10)) {

-            goto illegal_request;

-        }

-

-        /* The request is used as the AIO opaque value, so add a ref.  */

-        scsi_req_ref(&r->req);

-        r->req.aiocb = bdrv_aio_discard(s->qdev.conf.bs,

-                                        r->req.cmd.lba * (s->qdev.blocksize / 512),

-                                        nb_sectors * (s->qdev.blocksize / 512),

-                                        scsi_aio_complete, r);

-        return 0;

+        DPRINTF("WRITE SAME %d (len %lu)\n",

+                req->cmd.buf[0] == WRITE_SAME_10 ? 10 : 16,

+                (long)r->req.cmd.xfer);

+        break;

     default:

         DPRINTF("Unknown SCSI command (%2.2x)\n", buf[0]);

         scsi_check_condition(r, SENSE_CODE(INVALID_OPCODE));

-- 

1.7.11.7