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[Qemu-block] [PATCH 2/9] block: BLK_PERM_WRITE includes ..._UNCHANGED
From: |
Max Reitz |
Subject: |
[Qemu-block] [PATCH 2/9] block: BLK_PERM_WRITE includes ..._UNCHANGED |
Date: |
Mon, 16 Apr 2018 18:58:42 +0200 |
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 then WRITE,
we should probably explicitly document WRITE to include WRITE_UNCHANGED.
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,
--
2.14.3