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[Qemu-block] [PULL 25/37] block: BLK_PERM_WRITE includes ..._UNCHANGED
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PULL 25/37] block: BLK_PERM_WRITE includes ..._UNCHANGED |
Date: |
Tue, 15 May 2018 17:40:21 +0200 |
From: Max Reitz <address@hidden>
Currently we never actually check whether the WRITE_UNCHANGED
permission has been taken for unchanging writes. But the one check that
is commented out checks both WRITE and WRITE_UNCHANGED; and considering
that WRITE_UNCHANGED is already documented as being weaker than WRITE,
we should probably explicitly document WRITE to include WRITE_UNCHANGED.
Signed-off-by: Max Reitz <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Alberto Garcia <address@hidden>
Message-id: address@hidden
Reviewed-by: Kevin Wolf <address@hidden>
Signed-off-by: Max Reitz <address@hidden>
---
include/block/block.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/block/block.h b/include/block/block.h
index cdec3639a3..397b5e8d44 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -205,6 +205,9 @@ enum {
* This permission (which is weaker than BLK_PERM_WRITE) is both enough and
* required for writes to the block node when the caller promises that
* the visible disk content doesn't change.
+ *
+ * As the BLK_PERM_WRITE permission is strictly stronger, either is
+ * sufficient to perform an unchanging write.
*/
BLK_PERM_WRITE_UNCHANGED = 0x04,
--
2.13.6
- [Qemu-block] [PULL 17/37] iotests: Split 214 off of 122, (continued)
- [Qemu-block] [PULL 17/37] iotests: Split 214 off of 122, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 22/37] iotests: Add failure matching to common.qemu, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 20/37] qcow2: Give the refcount cache the minimum possible size by default, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 21/37] docs: Document the new default sizes of the qcow2 caches, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 26/37] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 28/37] block/quorum: Support BDRV_REQ_WRITE_UNCHANGED, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 18/37] Fix error message about compressed clusters with OFLAG_COPIED, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 23/37] iotests: Skip 181 and 201 without userfaultfd, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 27/37] block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 25/37] block: BLK_PERM_WRITE includes ..._UNCHANGED,
Kevin Wolf <=
- [Qemu-block] [PULL 31/37] iotests: Copy 197 for COR filter driver, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 29/37] block: Support BDRV_REQ_WRITE_UNCHANGED in filters, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 24/37] block: Add COR filter driver, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 34/37] block: Document BDRV_REQ_WRITE_UNCHANGED support, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 30/37] iotests: Clean up wrap image in 197, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 33/37] qemu-img: Check post-truncation size, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 35/37] qemu-io: Use purely string blockdev options, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 32/37] iotests: Add test for COR across nodes, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 36/37] qemu-img: Use only string options in img_open_opts, Kevin Wolf, 2018/05/15
- [Qemu-block] [PULL 37/37] iotests: Add test for -U/force-share conflicts, Kevin Wolf, 2018/05/15