From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org
Subject: [Qemu-devel] [PULL 09/13] block: Fix documentation for BDRV_REQ_MAY_UNMAP
Date: Mon, 30 Jul 2018 17:09:54 +0200 [thread overview]
Message-ID: <20180730150958.14607-10-kwolf@redhat.com> (raw)
In-Reply-To: <20180730150958.14607-1-kwolf@redhat.com>
BDRV_REQ_MAY_UNMAP in a write_zeroes request does not only allow the
driver to unmap the blocks, but it actively requests that the blocks be
unmapped afterwards if at all possible.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
include/block/block.h | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index f85e3a6ed3..4e0871aaf9 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -43,11 +43,12 @@ typedef struct BlockFragInfo {
typedef enum {
BDRV_REQ_COPY_ON_READ = 0x1,
BDRV_REQ_ZERO_WRITE = 0x2,
- /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
- * is allowed to optimize a write zeroes request by unmapping (discarding)
- * blocks if it is guaranteed that the result will read back as
- * zeroes. The flag is only passed to the driver if the block device is
- * opened with BDRV_O_UNMAP.
+
+ /*
+ * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
+ * that the block driver should unmap (discard) blocks if it is guaranteed
+ * that the result will read back as zeroes. The flag is only passed to the
+ * driver if the block device is opened with BDRV_O_UNMAP.
*/
BDRV_REQ_MAY_UNMAP = 0x4,
--
2.13.6
next prev parent reply other threads:[~2018-07-30 15:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-30 15:09 [Qemu-devel] [PULL 00/13] Block layer patches Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 01/13] qcow: fix a reference leak Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 02/13] qcow2: A grammar fix in conflicting cache sizing error message Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 03/13] file-posix: Handle EINTR in preallocation=full write Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 04/13] docs: Describe using images in writing iotests Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 05/13] iotests: Don't lock /dev/null in 226 Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 06/13] Revert "qemu-img: Document copy offloading implications with -S and -c" Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 07/13] qemu-img: Add -C option for convert with copy offloading Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 08/13] iotests: Add test for 'qemu-img convert -C' compatibility Kevin Wolf
2018-07-30 15:09 ` Kevin Wolf [this message]
2018-07-30 15:09 ` [Qemu-devel] [PULL 10/13] file-posix: Fix write_zeroes with unmap on block devices Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 11/13] block/qapi: Add 'qdev' field to query-blockstats result Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 12/13] block/qapi: Include anonymous BBs in query-blockstats Kevin Wolf
2018-07-30 15:09 ` [Qemu-devel] [PULL 13/13] qemu-iotests: Test query-blockstats with -drive and -blockdev Kevin Wolf
2018-07-31 9:02 ` [Qemu-devel] [PULL 00/13] Block layer patches Peter Maydell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180730150958.14607-10-kwolf@redhat.com \
--to=kwolf@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-block@nongnu.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.