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[Qemu-devel] [PATCH v2 12/18] block: allow waiting only for overlapping
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v2 12/18] block: allow waiting only for overlapping writes |
Date: |
Thu, 26 Jan 2012 18:22:43 +0100 |
To implement mismatching block size, we will reuse the request tracking
mechanism that is used for copy-on-read. However, waiting for overlapping
reads is not needed to protect against "torn reads", so add a flag to
wait_for_overlapping_requests.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block.c | 13 ++++++++++---
1 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index af41fb3..76e1c6a 100644
--- a/block.c
+++ b/block.c
@@ -1198,7 +1198,7 @@ static bool tracked_request_overlaps(BdrvTrackedRequest
*req,
}
static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors)
+ int64_t sector_num, int nb_sectors, bool writes_only)
{
BdrvTrackedRequest *req;
int64_t cluster_sector_num;
@@ -1214,9 +1214,16 @@ static void coroutine_fn
wait_for_overlapping_requests(BlockDriverState *bs,
round_to_clusters(bs, sector_num, nb_sectors,
&cluster_sector_num, &cluster_nb_sectors);
+ if (writes_only && !(bs->open_flags & BDRV_O_RDWR)) {
+ return;
+ }
+
do {
retry = false;
QLIST_FOREACH(req, &bs->tracked_requests, list) {
+ if (writes_only && !req->is_write) {
+ continue;
+ }
if (tracked_request_overlaps(req, cluster_sector_num,
cluster_nb_sectors)) {
/* Hitting this means there was a reentrant request, for
@@ -1591,7 +1598,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState
*bs,
}
if (bs->copy_on_read_in_flight) {
- wait_for_overlapping_requests(bs, sector_num, nb_sectors);
+ wait_for_overlapping_requests(bs, sector_num, nb_sectors, false);
}
tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
@@ -1665,7 +1672,7 @@ static int coroutine_fn
bdrv_co_do_writev(BlockDriverState *bs,
}
if (bs->copy_on_read_in_flight) {
- wait_for_overlapping_requests(bs, sector_num, nb_sectors);
+ wait_for_overlapping_requests(bs, sector_num, nb_sectors, false);
}
tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
--
1.7.7.6
- [Qemu-devel] [PATCH v2 03/18] block: pass protocol flags up to the format, (continued)
- [Qemu-devel] [PATCH v2 03/18] block: pass protocol flags up to the format, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 02/18] block: store actual flags in bs->open_flags, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 04/18] block: non-raw protocols never cache, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 05/18] block: remove enable_write_cache, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 06/18] block: move flag bits together, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 07/18] raw: remove the aligned_buf, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 09/18] block: add host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 11/18] iscsi: save host block size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 08/18] block: rename buffer_alignment to guest_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 10/18] raw: probe host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 12/18] block: allow waiting only for overlapping writes,
Paolo Bonzini <=
- [Qemu-devel] [PATCH v2 14/18] block: protect against "torn reads" for guest_block_size > host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 17/18] block: default min_io_size to host block size when doing rmw, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 16/18] block: default physical block size to host block size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 18/18] qemu-io: add blocksize argument to open, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 15/18] block: align and serialize I/O when guest_block_size < host_block_size, Paolo Bonzini, 2012/01/26
- [Qemu-devel] [PATCH v2 13/18] block: allow waiting at arbitrary granularity, Paolo Bonzini, 2012/01/26