From e0f594c3eac9fb0a89c76de3b77bce03c235b36e Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Tue, 3 Dec 2013 15:31:25 +0100

Subject: [PATCH 16/37] block: Switch BdrvTrackedRequest to byte granularity

Message-id: <1392117622-28812-17-git-send-email-kwolf@redhat.com>

Patchwork-id: 57181

O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 16/37] block: Switch BdrvTrackedRequest to byte granularity

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>

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 793ed47a7a2b09b67cb2a8863dff531436532b5c)

Conflicts:

	block/backup.c

	include/block/block_int.h

Conflicts because in RHEL 7...

- ...block-backup doesn't exist

- ...BdrvTrackedRequest is in block.c rather than block_int.h

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

---

 block.c | 56 ++++++++++++++++++++++++++++++++++++--------------------

 1 file changed, 36 insertions(+), 20 deletions(-)

---

 block.c |   56 ++++++++++++++++++++++++++++++++++++--------------------

 1 files changed, 36 insertions(+), 20 deletions(-)

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

index 7b8131c..09bb127 100644

--- a/block.c

+++ b/block.c

@@ -2036,8 +2036,8 @@ int bdrv_commit_all(void)

 struct BdrvTrackedRequest {

     BlockDriverState *bs;

-    int64_t sector_num;

-    int nb_sectors;

+    int64_t offset;

+    unsigned int bytes;

     bool is_write;

     QLIST_ENTRY(BdrvTrackedRequest) list;

     Coroutine *co; /* owner, used for deadlock detection */

@@ -2060,13 +2060,13 @@ static void tracked_request_end(BdrvTrackedRequest *req)

  */

 static void tracked_request_begin(BdrvTrackedRequest *req,

                                   BlockDriverState *bs,

-                                  int64_t sector_num,

-                                  int nb_sectors, bool is_write)

+                                  int64_t offset,

+                                  unsigned int bytes, bool is_write)

 {

     *req = (BdrvTrackedRequest){

         .bs = bs,

-        .sector_num = sector_num,

-        .nb_sectors = nb_sectors,

+        .offset = offset,

+        .bytes = bytes,

         .is_write = is_write,

         .co = qemu_coroutine_self(),

     };

@@ -2097,25 +2097,43 @@ void bdrv_round_to_clusters(BlockDriverState *bs,

     }

 }

+static void round_bytes_to_clusters(BlockDriverState *bs,

+                                    int64_t offset, unsigned int bytes,

+                                    int64_t *cluster_offset,

+                                    unsigned int *cluster_bytes)

+{

+    BlockDriverInfo bdi;

+

+    if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {

+        *cluster_offset = offset;

+        *cluster_bytes = bytes;

+    } else {

+        *cluster_offset = QEMU_ALIGN_DOWN(offset, bdi.cluster_size);

+        *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes,

+                                       bdi.cluster_size);

+    }

+}

+

 static bool tracked_request_overlaps(BdrvTrackedRequest *req,

-                                     int64_t sector_num, int nb_sectors) {

+                                     int64_t offset, unsigned int bytes)

+{

     /*        aaaa   bbbb */

-    if (sector_num >= req->sector_num + req->nb_sectors) {

+    if (offset >= req->offset + req->bytes) {

         return false;

     }

     /* bbbb   aaaa        */

-    if (req->sector_num >= sector_num + nb_sectors) {

+    if (req->offset >= offset + bytes) {

         return false;

     }

     return true;

 }

 static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,

-        int64_t sector_num, int nb_sectors)

+        int64_t offset, unsigned int bytes)

 {

     BdrvTrackedRequest *req;

-    int64_t cluster_sector_num;

-    int cluster_nb_sectors;

+    int64_t cluster_offset;

+    unsigned int cluster_bytes;

     bool retry;

     /* If we touch the same cluster it counts as an overlap.  This guarantees

@@ -2124,14 +2142,12 @@ static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,

      * CoR read and write operations are atomic and guest writes cannot

      * interleave between them.

      */

-    bdrv_round_to_clusters(bs, sector_num, nb_sectors,

-                           &cluster_sector_num, &cluster_nb_sectors);

+    round_bytes_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes);

     do {

         retry = false;

         QLIST_FOREACH(req, &bs->tracked_requests, list) {

-            if (tracked_request_overlaps(req, cluster_sector_num,

-                                         cluster_nb_sectors)) {

+            if (tracked_request_overlaps(req, cluster_offset, cluster_bytes)) {

                 /* Hitting this means there was a reentrant request, for

                  * example, a block driver issuing nested requests.  This must

                  * never happen since it means deadlock.

@@ -2746,10 +2762,10 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,

     }

     if (bs->copy_on_read_in_flight) {

-        wait_for_overlapping_requests(bs, sector_num, nb_sectors);

+        wait_for_overlapping_requests(bs, offset, bytes);

     }

-    tracked_request_begin(&req, bs, sector_num, nb_sectors, false);

+    tracked_request_begin(&req, bs, offset, bytes, false);

     if (flags & BDRV_REQ_COPY_ON_READ) {

         int pnum;

@@ -2998,10 +3014,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,

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

     if (bs->copy_on_read_in_flight) {

-        wait_for_overlapping_requests(bs, sector_num, nb_sectors);

+        wait_for_overlapping_requests(bs, offset, bytes);

     }

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

+    tracked_request_begin(&req, bs, offset, bytes, true);

     if (flags & BDRV_REQ_ZERO_WRITE) {

         ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);

-- 

1.7.1