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[Qemu-devel] [PATCH 09/11] raw-posix: implement write_zeroes with MAY_UN
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 09/11] raw-posix: implement write_zeroes with MAY_UNMAP for block devices |
Date: |
Tue, 12 Nov 2013 16:49:47 +0100 |
See the next commit for the description of the Linux kernel problem
that is worked around in raw_open_common.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/raw-posix.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 830e109..5cb46f1 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -335,6 +335,23 @@ static int raw_open_common(BlockDriverState *bs, QDict
*options,
if (S_ISREG(st.st_mode)) {
s->discard_zeroes = true;
}
+#ifdef BLKDISCARDZEROES
+ if (S_ISBLK(st.st_mode)) {
+ unsigned int arg;
+ if (ioctl(s->fd, BLKDISCARDZEROES, &arg) == 0 && arg) {
+ s->discard_zeroes = true;
+ }
+ }
+#endif
+#ifdef CONFIG_LINUX
+ /* On Linux 3.10, BLKDISCARD leaves stale data in the page cache. Do
+ * not rely on the contents of discarded blocks unless using O_DIRECT.
+ */
+ if (!(bs->open_flags & BDRV_O_NOCACHE)) {
+ s->discard_zeroes = false;
+ }
+#endif
+ }
#ifdef CONFIG_XFS
if (platform_test_xfs_fd(s->fd)) {
@@ -1587,6 +1604,26 @@ static coroutine_fn BlockDriverAIOCB
*hdev_aio_discard(BlockDriverState *bs,
cb, opaque, QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV);
}
+static coroutine_fn int hdev_co_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
+{
+ BDRVRawState *s = bs->opaque;
+ int rc;
+
+ rc = fd_open(bs);
+ if (rc < 0) {
+ return rc;
+ }
+ if (!(flags & BDRV_REQ_MAY_UNMAP)) {
+ return -ENOTSUP;
+ }
+ if (!s->discard_zeroes) {
+ return -ENOTSUP;
+ }
+ return paio_submit_co(bs, s->fd, sector_num, NULL, nb_sectors,
+ QEMU_AIO_DISCARD|QEMU_AIO_BLKDEV);
+}
+
static int hdev_create(const char *filename, QEMUOptionParameter *options,
Error **errp)
{
@@ -1639,6 +1676,7 @@ static BlockDriver bdrv_host_device = {
.bdrv_reopen_abort = raw_reopen_abort,
.bdrv_create = hdev_create,
.create_options = raw_create_options,
+ .bdrv_co_write_zeroes = hdev_co_write_zeroes,
.bdrv_aio_readv = raw_aio_readv,
.bdrv_aio_writev = raw_aio_writev,
--
1.8.4.2
- [Qemu-devel] [PATCH 01/11] block: generalize BlockLimits handling to cover bdrv_aio_discard too, (continued)
- [Qemu-devel] [PATCH 01/11] block: generalize BlockLimits handling to cover bdrv_aio_discard too, Paolo Bonzini, 2013/11/12
- [Qemu-devel] [PATCH 06/11] scsi-disk: correctly implement WRITE SAME, Paolo Bonzini, 2013/11/12
- [Qemu-devel] [PATCH 07/11] block: handle ENOTSUP from discard in generic code, Paolo Bonzini, 2013/11/12
- [Qemu-devel] [PATCH 08/11] raw-posix: implement write_zeroes with MAY_UNMAP for files, Paolo Bonzini, 2013/11/12
- [Qemu-devel] [PATCH 10/11] raw-posix: add support for write_zeroes on XFS and block devices, Paolo Bonzini, 2013/11/12
- [Qemu-devel] [PATCH 09/11] raw-posix: implement write_zeroes with MAY_UNMAP for block devices,
Paolo Bonzini <=
[Qemu-devel] [PATCH 11/11] qemu-iotests: 033 is fast, Paolo Bonzini, 2013/11/12
[Qemu-devel] [PATCH 05/11] scsi-disk: reject ANCHOR=1 for UNMAP and WRITE SAME commands, Paolo Bonzini, 2013/11/12