From d6a03733e6755d4b59f8009239af8f0a3e12c171 Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Tue, 3 Dec 2013 14:02:23 +0100

Subject: [PATCH 13/37] block: Introduce bdrv_aligned_pwritev()

Message-id: <1392117622-28812-14-git-send-email-kwolf@redhat.com>

Patchwork-id: 57178

O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 13/37] block: Introduce bdrv_aligned_pwritev()

Bugzilla: 748906

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

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

RH-Acked-by: Max Reitz <mreitz@redhat.com>

This separates the part of bdrv_co_do_writev() that needs to happen

before the request is modified to match the backend alignment, and a

part that needs to be executed afterwards and passes the request to the

BlockDriver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Reviewed-by: Benoit Canet <benoit@irqsave.net>

(cherry picked from commit b404f72036716ab8ace04b83a8f0a93be4739a6a)

Conflicts:

	block.c

Conflict because RHEL 7 still has the old I/O throttling code.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

 block.c | 62 +++++++++++++++++++++++++++++++++++++++++---------------------

 1 file changed, 41 insertions(+), 21 deletions(-)

---

 block.c |   62 +++++++++++++++++++++++++++++++++++++++++---------------------

 1 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/block.c b/block.c

index ce3edb0..e6b6ed4 100644

--- a/block.c

+++ b/block.c

@@ -2982,34 +2982,20 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,

 }

 /*

- * Handle a write request in coroutine context

+ * Forwards an already correctly aligned write request to the BlockDriver.

  */

-static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,

-    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,

-    BdrvRequestFlags flags)

+static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,

+    int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)

 {

     BlockDriver *drv = bs->drv;

     BdrvTrackedRequest req;

     int ret;

-    if (!bs->drv) {

-        return -ENOMEDIUM;

-    }

-    if (bs->read_only) {

-        return -EACCES;

-    }

-    if (bdrv_check_request(bs, sector_num, nb_sectors)) {

-        return -EIO;

-    }

-

-    /* throttling disk write I/O */

-    if (bs->io_limits_enabled) {

-        bdrv_io_limits_intercept(bs, true, nb_sectors);

-    }

+    int64_t sector_num = offset >> BDRV_SECTOR_BITS;

+    unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;

-    if (bs->copy_on_read_in_flight) {

-        wait_for_overlapping_requests(bs, sector_num, nb_sectors);

-    }

+    assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);

+    assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);

     tracked_request_begin(&req, bs, sector_num, nb_sectors, true);

@@ -3039,6 +3025,40 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,

     return ret;

 }

+/*

+ * Handle a write request in coroutine context

+ */

+static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,

+    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,

+    BdrvRequestFlags flags)

+{

+    int ret;

+

+    if (!bs->drv) {

+        return -ENOMEDIUM;

+    }

+    if (bs->read_only) {

+        return -EACCES;

+    }

+    if (bdrv_check_request(bs, sector_num, nb_sectors)) {

+        return -EIO;

+    }

+

+    if (bs->copy_on_read_in_flight) {

+        wait_for_overlapping_requests(bs, sector_num, nb_sectors);

+    }

+

+    /* throttling disk I/O */

+    if (bs->io_limits_enabled) {

+        bdrv_io_limits_intercept(bs, true, nb_sectors);

+    }

+

+    ret = bdrv_aligned_pwritev(bs, sector_num << BDRV_SECTOR_BITS,

+                               nb_sectors << BDRV_SECTOR_BITS, qiov, flags);

+

+    return ret;

+}

+

 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,

     int nb_sectors, QEMUIOVector *qiov)

 {

-- 

1.7.1