From: Max Reitz <mre...@redhat.com>
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 <mre...@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
Reviewed-by: Alberto Garcia <be...@igalia.com>
Message-id: 20180421132929.21610-3-mre...@redhat.com
Reviewed-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Max Reitz <mre...@redhat.com>
---
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
