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From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [PATCH v4 12/19] quorum: Stop marking it as a filter
Date: Tue, 18 Feb 2020 11:34:47 +0100	[thread overview]
Message-ID: <20200218103454.296704-13-mreitz@redhat.com> (raw)
In-Reply-To: <20200218103454.296704-1-mreitz@redhat.com>

Quorum is not a filter, for example because it cannot guarantee which of
its children will serve the next request.  Thus, any of its children may
differ from the data visible to quorum's parents.

We have other filters with multiple children, but they differ in this
aspect:

- blkverify quits the whole qemu process if its children differ.  As
  such, we can always skip it when we want to skip it (as a filter node)
  by going to any of its children.  Both have the same data.

- replication generally serves requests from bs->file, so this is its
  only actually filtered child.

- Block job filters currently only have one child, but they will
  probably get more children in the future.  Still, they will always
  have only one actually filtered child.

Having "filters" as a dedicated node category only makes sense if you
can skip them by going to a one fixed child that always shows the same
data as the filter node.  Quorum cannot fulfill this, so it is not a
filter.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/quorum.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/block/quorum.c b/block/quorum.c
index f57b0402d9..6d7a56bd93 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1198,7 +1198,6 @@ static BlockDriver bdrv_quorum = {
 
     .bdrv_child_perm                    = quorum_child_perm,
 
-    .is_filter                          = true,
     .bdrv_recurse_can_replace           = quorum_recurse_can_replace,
 
     .strong_runtime_opts                = quorum_strong_runtime_opts,
-- 
2.24.1



  parent reply	other threads:[~2020-02-18 10:43 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-18 10:34 [PATCH v4 00/19] block: Fix check_to_replace_node() Max Reitz
2020-02-18 10:34 ` [PATCH v4 01/19] blockdev: Allow external snapshots everywhere Max Reitz
2020-02-18 10:34 ` [PATCH v4 02/19] blockdev: Allow resizing everywhere Max Reitz
2020-02-18 10:34 ` [PATCH v4 03/19] block: Drop bdrv_is_first_non_filter() Max Reitz
2020-02-18 10:34 ` [PATCH v4 04/19] iotests: Let 041 use -blockdev for quorum children Max Reitz
2020-02-18 10:34 ` [PATCH v4 05/19] quorum: Fix child permissions Max Reitz
2020-02-18 10:34 ` [PATCH v4 06/19] block: Add bdrv_recurse_can_replace() Max Reitz
2020-02-18 10:34 ` [PATCH v4 07/19] blkverify: Implement .bdrv_recurse_can_replace() Max Reitz
2020-02-18 10:34 ` [PATCH v4 08/19] quorum: " Max Reitz
2020-02-18 10:34 ` [PATCH v4 09/19] block: Use bdrv_recurse_can_replace() Max Reitz
2020-02-18 10:34 ` [PATCH v4 10/19] block: Remove bdrv_recurse_is_first_non_filter() Max Reitz
2020-02-18 10:34 ` [PATCH v4 11/19] mirror: Double-check immediately before replacing Max Reitz
2020-02-18 10:34 ` Max Reitz [this message]
2020-02-18 10:34 ` [PATCH v4 13/19] iotests: Use complete_and_wait() in 155 Max Reitz
2020-02-18 10:34 ` [PATCH v4 14/19] iotests: Add VM.assert_block_path() Max Reitz
2020-02-18 10:34 ` [PATCH v4 15/19] iotests/041: Drop superfluous shutdowns Max Reitz
2020-02-18 10:34 ` [PATCH v4 16/19] iotests: Resolve TODOs in 041 Max Reitz
2020-02-18 10:34 ` [PATCH v4 17/19] iotests: Use self.image_len in TestRepairQuorum Max Reitz
2020-02-18 10:34 ` [PATCH v4 18/19] iotests: Add tests for invalid Quorum @replaces Max Reitz
2020-02-18 12:38   ` Kevin Wolf
2020-02-18 12:49     ` Max Reitz
2020-02-18 13:29       ` Kevin Wolf
2020-02-18 10:34 ` [PATCH v4 19/19] iotests: Check that @replaces can replace filters Max Reitz
2020-02-18 13:53 ` [PATCH v4 00/19] block: Fix check_to_replace_node() Kevin Wolf

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