From: Eric Blake <eblake@redhat.com>
To: qemu-devel@nongnu.org
Cc: david.edmondson@oracle.com, Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org, mreitz@redhat.com
Subject: [PATCH 04/17] block: Improve documentation of .bdrv_has_zero_init
Date: Fri, 31 Jan 2020 11:44:23 -0600 [thread overview]
Message-ID: <20200131174436.2961874-5-eblake@redhat.com> (raw)
In-Reply-To: <20200131174436.2961874-1-eblake@redhat.com>
Several drivers supply .bdrv_has_zero_init that returns 1, but lack
the .bdrv_has_zero_init_truncate callback (parallels and qed outright,
vdi in some scenarios). A literal reading of the existing
documentation says such drivers are broken, because
bdrv_has_zero_init_truncate() defaults to zero if the callback is
missing; but in practice, the tie between the two functions is only
relevant when truncate is supported. Clarify the documentation to
make it obvious that this is okay.
Fixes: 1dcaf527
Signed-off-by: Eric Blake <eblake@redhat.com>
---
include/block/block_int.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 640fb82c789e..77ab45dc87cf 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -444,7 +444,8 @@ struct BlockDriver {
/*
* Returns 1 if newly created images are guaranteed to contain only
* zeros, 0 otherwise.
- * Must return 0 if .bdrv_has_zero_init_truncate() returns 0.
+ * Must return 0 if .bdrv_co_truncate is set and
+ * .bdrv_has_zero_init_truncate() returns 0.
*/
int (*bdrv_has_zero_init)(BlockDriverState *bs);
--
2.24.1
next prev parent reply other threads:[~2020-01-31 17:46 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 17:44 [PATCH 00/17] Improve qcow2 all-zero detection Eric Blake
2020-01-31 17:44 ` [PATCH 01/17] qcow2: Comment typo fixes Eric Blake
2020-02-04 14:12 ` Vladimir Sementsov-Ogievskiy
2020-02-09 19:34 ` Alberto Garcia
2020-01-31 17:44 ` [PATCH 02/17] qcow2: List autoclear bit names in header Eric Blake
2020-02-04 14:26 ` Vladimir Sementsov-Ogievskiy
2020-01-31 17:44 ` [PATCH 03/17] qcow2: Avoid feature name extension on small cluster size Eric Blake
2020-02-04 14:39 ` Vladimir Sementsov-Ogievskiy
2020-02-09 19:28 ` Alberto Garcia
2020-01-31 17:44 ` Eric Blake [this message]
2020-02-04 15:03 ` [PATCH 04/17] block: Improve documentation of .bdrv_has_zero_init Vladimir Sementsov-Ogievskiy
2020-02-04 15:16 ` Eric Blake
2020-01-31 17:44 ` [PATCH 05/17] block: Don't advertise zero_init_truncate with encryption Eric Blake
2020-02-10 18:12 ` Alberto Garcia
2020-01-31 17:44 ` [PATCH 06/17] block: Improve bdrv_has_zero_init_truncate with backing file Eric Blake
2020-02-10 18:13 ` Alberto Garcia
2020-01-31 17:44 ` [PATCH 07/17] gluster: Drop useless has_zero_init callback Eric Blake
2020-02-04 15:06 ` Vladimir Sementsov-Ogievskiy
2020-02-10 18:21 ` Alberto Garcia
2020-02-17 8:06 ` [GEDI] " Niels de Vos
2020-02-17 12:03 ` Eric Blake
2020-02-17 12:22 ` Eric Blake
2020-02-17 14:01 ` Niels de Vos
2020-01-31 17:44 ` [PATCH 08/17] sheepdog: Consistently set bdrv_has_zero_init_truncate Eric Blake
2020-02-04 15:09 ` Vladimir Sementsov-Ogievskiy
2020-01-31 17:44 ` [PATCH 09/17] block: Refactor bdrv_has_zero_init{,_truncate} Eric Blake
2020-02-04 15:35 ` Vladimir Sementsov-Ogievskiy
2020-02-04 15:49 ` Eric Blake
2020-02-04 16:07 ` Vladimir Sementsov-Ogievskiy
2020-02-04 17:42 ` Max Reitz
2020-02-04 17:51 ` Eric Blake
2020-02-05 16:43 ` Max Reitz
2020-02-05 7:51 ` Vladimir Sementsov-Ogievskiy
2020-02-05 14:07 ` Eric Blake
2020-02-05 14:25 ` Vladimir Sementsov-Ogievskiy
2020-02-05 14:36 ` Eric Blake
2020-02-05 17:55 ` Max Reitz
2020-02-04 17:53 ` Max Reitz
2020-02-04 19:03 ` Eric Blake
2020-02-05 17:22 ` Max Reitz
2020-02-05 18:39 ` Eric Blake
2020-02-06 9:18 ` Max Reitz
2020-01-31 17:44 ` [PATCH 10/17] block: Add new BDRV_ZERO_OPEN flag Eric Blake
2020-01-31 18:03 ` Eric Blake
2020-02-04 17:34 ` Max Reitz
2020-02-04 17:50 ` Eric Blake
2020-02-05 8:39 ` Vladimir Sementsov-Ogievskiy
2020-02-05 17:26 ` Max Reitz
2020-01-31 17:44 ` [PATCH 11/17] file-posix: Support BDRV_ZERO_OPEN Eric Blake
2020-01-31 17:44 ` [PATCH 12/17] gluster: " Eric Blake
2020-02-17 8:16 ` [GEDI] " Niels de Vos
2020-01-31 17:44 ` [PATCH 13/17] qcow2: Add new autoclear feature for all zero image Eric Blake
2020-02-03 17:45 ` Vladimir Sementsov-Ogievskiy
2020-02-04 13:12 ` Eric Blake
2020-02-04 13:29 ` Vladimir Sementsov-Ogievskiy
2020-01-31 17:44 ` [PATCH 14/17] qcow2: Expose all zero bit through .bdrv_known_zeroes Eric Blake
2020-01-31 17:44 ` [PATCH 15/17] qcow2: Implement all-zero autoclear bit Eric Blake
2020-01-31 17:44 ` [PATCH 16/17] iotests: Add new test for qcow2 all-zero bit Eric Blake
2020-01-31 17:44 ` [PATCH 17/17] qcow2: Let qemu-img check cover " Eric Blake
2020-02-04 17:32 ` [PATCH 00/17] Improve qcow2 all-zero detection Max Reitz
2020-02-04 18:53 ` Eric Blake
2020-02-05 17:04 ` Max Reitz
2020-02-05 19:21 ` Eric Blake
2020-02-06 9:12 ` Max Reitz
2020-02-05 9:04 ` Vladimir Sementsov-Ogievskiy
2020-02-05 9:25 ` Vladimir Sementsov-Ogievskiy
2020-02-05 14:26 ` Eric Blake
2020-02-05 14:47 ` Vladimir Sementsov-Ogievskiy
2020-02-05 15:14 ` Vladimir Sementsov-Ogievskiy
2020-02-05 17:58 ` Max Reitz
2020-02-05 14:22 ` Eric Blake
2020-02-05 14:43 ` Vladimir Sementsov-Ogievskiy
2020-02-05 14:58 ` Vladimir Sementsov-Ogievskiy
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