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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: kwolf@redhat.com, pl@kamp.de, ronniesahlberg@gmail.com,
	stefanha@redhat.com
Subject: [Qemu-devel] [PATCH v3 14/19] raw-posix: implement write_zeroes with MAY_UNMAP for block devices
Date: Fri, 22 Nov 2013 13:39:56 +0100	[thread overview]
Message-ID: <1385124001-3576-15-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1385124001-3576-1-git-send-email-pbonzini@redhat.com>

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 <pbonzini@redhat.com>
---
 block/raw-posix.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 7f3f47d..b3feed6 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -334,6 +334,22 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     if (S_ISREG(st.st_mode)) {
         s->discard_zeroes = true;
     }
+    if (S_ISBLK(st.st_mode)) {
+#ifdef BLKDISCARDZEROES
+        unsigned int arg;
+        if (ioctl(s->fd, BLKDISCARDZEROES, &arg) == 0 && arg) {
+            s->discard_zeroes = true;
+        }
+#endif
+#ifdef __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)) {
@@ -1586,6 +1602,26 @@ 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)
 {
@@ -1638,6 +1674,7 @@ 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

  parent reply	other threads:[~2013-11-22 12:41 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-22 12:39 [Qemu-devel] [PATCH v3 00/19] block & scsi: write_zeroes support through the whole stack Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 01/19] block: generalize BlockLimits handling to cover bdrv_aio_discard too Paolo Bonzini
2013-11-25  9:09   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 02/19] block: add flags to BlockRequest Paolo Bonzini
2013-11-25  9:11   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 03/19] block: add flags argument to bdrv_co_write_zeroes tracepoint Paolo Bonzini
2013-11-25  9:12   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 04/19] block: add bdrv_aio_write_zeroes Paolo Bonzini
2013-11-25  9:13   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 05/19] block: handle ENOTSUP from discard in generic code Paolo Bonzini
2013-11-25 10:06   ` Peter Lieven
2013-11-25 10:16     ` Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 06/19] block: make bdrv_co_do_write_zeroes stricter in producing aligned requests Paolo Bonzini
2013-11-25 10:23   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 07/19] vpc, vhdx: add get_info Paolo Bonzini
2013-11-25 10:27   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 08/19] block drivers: add discard/write_zeroes properties to bdrv_get_info implementation Paolo Bonzini
2013-11-25 10:29   ` Peter Lieven
2013-12-03 15:09   ` Kevin Wolf
2013-12-03 15:21     ` Paolo Bonzini
2013-12-03 17:10       ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 09/19] block drivers: expose requirement for write same alignment from formats Paolo Bonzini
2013-11-25 10:33   ` Peter Lieven
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 10/19] block/iscsi: remove .bdrv_has_zero_init Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 11/19] block/iscsi: updated copyright Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 12/19] block/iscsi: check WRITE SAME support differently depending on MAY_UNMAP Paolo Bonzini
2013-11-25 10:34   ` Peter Lieven
2013-11-25 10:42     ` Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 13/19] raw-posix: implement write_zeroes with MAY_UNMAP for files Paolo Bonzini
2013-11-22 12:39 ` Paolo Bonzini [this message]
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 15/19] raw-posix: add support for write_zeroes on XFS and block devices Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 16/19] qemu-iotests: 033 is fast Paolo Bonzini
2013-11-22 12:39 ` [Qemu-devel] [PATCH v3 17/19] scsi-disk: catch write protection errors in UNMAP Paolo Bonzini
2013-11-22 12:40 ` [Qemu-devel] [PATCH v3 18/19] scsi-disk: reject ANCHOR=1 for UNMAP and WRITE SAME commands Paolo Bonzini
2013-11-22 12:40 ` [Qemu-devel] [PATCH v3 19/19] scsi-disk: correctly implement WRITE SAME Paolo Bonzini
2013-12-03 14:29 ` [Qemu-devel] [PATCH v3 00/19] block & scsi: write_zeroes support through the whole stack Stefan Hajnoczi

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