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[Qemu-devel] [PATCH 20/39] block: flush in writethrough mode after write
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 20/39] block: flush in writethrough mode after writes |
Date: |
Fri, 15 Jun 2012 15:33:20 +0200 |
From: Paolo Bonzini <address@hidden>
We want to make the formats handle their own flushes
autonomously, while keeping for guests the ability to use a writethrough
cache. Since formats will write metadata via bs->file, bdrv_co_do_writev
is the only place where we need to add a flush.
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 11 +++++++++--
1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index 85ef6af..7538112 100644
--- a/block.c
+++ b/block.c
@@ -1758,8 +1758,8 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
return ret;
}
- /* No flush needed for cache modes that use O_DSYNC */
- if ((bs->open_flags & BDRV_O_CACHE_WB) != 0) {
+ /* No flush needed for cache modes that already do it */
+ if (bs->enable_write_cache) {
bdrv_flush(bs);
}
@@ -1808,6 +1808,9 @@ static int coroutine_fn
bdrv_co_do_copy_on_readv(BlockDriverState *bs,
ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
cluster_nb_sectors);
} else {
+ /* This does not change the data on the disk, it is not necessary
+ * to flush even in cache=writethrough mode.
+ */
ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,
&bounce_qiov);
}
@@ -1977,6 +1980,10 @@ static int coroutine_fn
bdrv_co_do_writev(BlockDriverState *bs,
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
}
+ if (ret == 0 && !bs->enable_write_cache) {
+ ret = bdrv_co_flush(bs);
+ }
+
if (bs->dirty_bitmap) {
set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
}
--
1.7.6.5
- [Qemu-devel] [PATCH 17/39] scsi-disk: Don't peek behind the BlockDriverState abstraction, (continued)
- [Qemu-devel] [PATCH 17/39] scsi-disk: Don't peek behind the BlockDriverState abstraction, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 10/39] qemu-img check: Print fixed clusters and recheck, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 16/39] block: New bdrv_get_flags(), Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 15/39] Prevent disk data loss when closing qemu, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 21/39] savevm: flush after saving vm state, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 18/39] qemu-iotests: fill streaming test image with data, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 22/39] block: copy enable_write_cache in bdrv_append, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 23/39] block: add bdrv_set_enable_write_cache, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 19/39] qemu-iotests: start vms in qtest mode, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 25/39] ide: support enable/disable write cache, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 20/39] block: flush in writethrough mode after writes,
Kevin Wolf <=
- [Qemu-devel] [PATCH 36/39] fdc: fix implied seek while there is no media in drive, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 38/39] qemu-iotests: add qcow2.py set-feature-bit command, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 39/39] qemu-iotests: add 036 autoclear feature bit test, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 30/39] qemu-iotests: COW with many AIO requests on the same cluster, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 31/39] qemu-img: document qed format on qemu-img man page, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 35/39] qcow2: fix autoclear image header update, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 37/39] fdc-test: introduced qtest read_without_media, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 28/39] qcow2: Fix avail_sectors in cluster allocation code, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 24/39] block: always open drivers in writeback mode, Kevin Wolf, 2012/06/15
- [Qemu-devel] [PATCH 33/39] xen: Don't change -drive if=xen device name during machine init, Kevin Wolf, 2012/06/15