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[Qemu-devel] [PATCH 13/17] block: allow waiting at arbitrary granularity
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 13/17] block: allow waiting at arbitrary granularity |
Date: |
Tue, 13 Dec 2011 13:37:16 +0100 |
When emulating small logical block sizes, the only overlaps
that matter are at host block size granularity, not cluster.
Make wait_for_overlapping_requests more flexible in this
respect, too.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block.c | 43 ++++++++++++++++++++++++++++---------------
1 files changed, 28 insertions(+), 15 deletions(-)
diff --git a/block.c b/block.c
index 9a2ef83..07b9cf4 100644
--- a/block.c
+++ b/block.c
@@ -1159,24 +1159,33 @@ static void tracked_request_begin(BdrvTrackedRequest
*req,
/**
* Round a region to cluster boundaries
*/
-static void round_to_clusters(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors,
- int64_t *cluster_sector_num,
- int *cluster_nb_sectors)
+static void round_sectors(int64_t alignment,
+ int64_t sector_num, int nb_sectors,
+ int64_t *cluster_sector_num,
+ int *cluster_nb_sectors)
{
- BlockDriverInfo bdi;
-
- if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
+ if (alignment == BDRV_SECTOR_SIZE) {
*cluster_sector_num = sector_num;
*cluster_nb_sectors = nb_sectors;
} else {
- int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE;
+ int64_t c = alignment / BDRV_SECTOR_SIZE;
*cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c);
*cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num +
nb_sectors, c);
}
}
+static int64_t get_cluster_size(BlockDriverState *bs)
+{
+ BlockDriverInfo bdi;
+
+ if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
+ return BDRV_SECTOR_SIZE;
+ } else {
+ return bdi.cluster_size / BDRV_SECTOR_SIZE;
+ }
+}
+
static bool tracked_request_overlaps(BdrvTrackedRequest *req,
int64_t sector_num, int nb_sectors) {
/* aaaa bbbb */
@@ -1191,7 +1200,8 @@ static bool tracked_request_overlaps(BdrvTrackedRequest
*req,
}
static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, bool writes_only)
+ int64_t sector_num, int nb_sectors,
+ int64_t granularity, bool writes_only)
{
BdrvTrackedRequest *req;
int64_t cluster_sector_num;
@@ -1204,8 +1214,8 @@ static void coroutine_fn
wait_for_overlapping_requests(BlockDriverState *bs,
* CoR read and write operations are atomic and guest writes cannot
* interleave between them.
*/
- round_to_clusters(bs, sector_num, nb_sectors,
- &cluster_sector_num, &cluster_nb_sectors);
+ round_sectors(granularity, sector_num, nb_sectors,
+ &cluster_sector_num, &cluster_nb_sectors);
if (writes_only && !(bs->open_flags & BDRV_O_RDWR)) {
return;
@@ -1525,8 +1535,9 @@ static int coroutine_fn
bdrv_co_copy_on_readv(BlockDriverState *bs,
/* Cover entire cluster so no additional backing file I/O is required when
* allocating cluster in the image file.
*/
- round_to_clusters(bs, sector_num, nb_sectors,
- &cluster_sector_num, &cluster_nb_sectors);
+ round_sectors(get_cluster_size(bs),
+ sector_num, nb_sectors,
+ &cluster_sector_num, &cluster_nb_sectors);
trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors,
cluster_sector_num, cluster_nb_sectors);
@@ -1583,7 +1594,8 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState
*bs,
}
if (bs->copy_on_read) {
- wait_for_overlapping_requests(bs, sector_num, nb_sectors, false);
+ wait_for_overlapping_requests(bs, sector_num, nb_sectors,
+ get_cluster_size(bs), false);
}
tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
@@ -1643,7 +1655,8 @@ static int coroutine_fn
bdrv_co_do_writev(BlockDriverState *bs,
}
if (bs->copy_on_read) {
- wait_for_overlapping_requests(bs, sector_num, nb_sectors, false);
+ wait_for_overlapping_requests(bs, sector_num, nb_sectors,
+ get_cluster_size(bs), false);
}
tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
--
1.7.7.1
- [Qemu-devel] [PATCH 06/17] block: move flag bits together, (continued)
- [Qemu-devel] [PATCH 06/17] block: move flag bits together, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 07/17] raw: remove the aligned_buf, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 08/17] block: rename buffer_alignment to guest_block_size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 09/17] block: add host_block_size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 11/17] iscsi: save host block size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 12/17] block: allow waiting only for overlapping writes, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 10/17] raw: probe host_block_size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 16/17] block: default physical block size to host block size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 14/17] block: protect against "torn reads" for guest_block_size > host_block_size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 15/17] block: align and serialize I/O when guest_block_size < host_block_size, Paolo Bonzini, 2011/12/13
- [Qemu-devel] [PATCH 13/17] block: allow waiting at arbitrary granularity,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 17/17] qemu-io: add blocksize argument to open, Paolo Bonzini, 2011/12/13
- Re: [Qemu-devel] [PATCH 00/17] Support mismatched host and guest logical block sizes, Kevin Wolf, 2011/12/14