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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 v3 13/21] mirror: Double-check immediately before replacing
Date: Thu, 30 Jan 2020 22:44:23 +0100	[thread overview]
Message-ID: <20200130214431.333510-14-mreitz@redhat.com> (raw)
In-Reply-To: <20200130214431.333510-1-mreitz@redhat.com>

There is no guarantee that we can still replace the node we want to
replace at the end of the mirror job.  Double-check by calling
bdrv_recurse_can_replace().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/mirror.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/block/mirror.c b/block/mirror.c
index cacbc70014..447051dbc6 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -700,7 +700,19 @@ static int mirror_exit_common(Job *job)
          * drain potential other users of the BDS before changing the graph. */
         assert(s->in_drain);
         bdrv_drained_begin(target_bs);
-        bdrv_replace_node(to_replace, target_bs, &local_err);
+        /*
+         * Cannot use check_to_replace_node() here, because that would
+         * check for an op blocker on @to_replace, and we have our own
+         * there.
+         */
+        if (bdrv_recurse_can_replace(src, to_replace)) {
+            bdrv_replace_node(to_replace, target_bs, &local_err);
+        } else {
+            error_setg(&local_err, "Can no longer replace '%s' by '%s', "
+                       "because it can no longer be guaranteed that doing so "
+                       "would not lead to an abrupt change of visible data",
+                       to_replace->node_name, target_bs->node_name);
+        }
         bdrv_drained_end(target_bs);
         if (local_err) {
             error_report_err(local_err);
-- 
2.24.1



  parent reply	other threads:[~2020-01-30 21:55 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-30 21:44 [PATCH v3 00/21] block: Fix check_to_replace_node() Max Reitz
2020-01-30 21:44 ` [PATCH v3 01/21] blockdev: Allow external snapshots everywhere Max Reitz
2020-01-30 21:44 ` [PATCH v3 02/21] blockdev: Allow resizing everywhere Max Reitz
2020-01-30 21:44 ` [PATCH v3 03/21] block: Drop bdrv_is_first_non_filter() Max Reitz
2020-01-30 21:44 ` [PATCH v3 04/21] iotests: Let 041 use -blockdev for quorum children Max Reitz
2020-01-30 21:44 ` [PATCH v3 05/21] quorum: Fix child permissions Max Reitz
2020-01-30 21:44 ` [PATCH v3 06/21] block: Add bdrv_recurse_can_replace() Max Reitz
2020-01-30 21:44 ` [PATCH v3 07/21] blkverify: Implement .bdrv_recurse_can_replace() Max Reitz
2020-01-30 21:44 ` [PATCH v3 08/21] quorum: Store children in own structure Max Reitz
2020-01-30 21:44 ` [PATCH v3 09/21] quorum: Add QuorumChild.to_be_replaced Max Reitz
2020-02-04  9:33   ` Vladimir Sementsov-Ogievskiy
2020-02-05 15:38   ` Kevin Wolf
2020-02-06 10:11     ` Max Reitz
2020-02-06 14:58       ` Kevin Wolf
2020-02-06 15:21         ` Max Reitz
2020-02-06 15:51           ` Kevin Wolf
2020-02-06 16:43             ` Max Reitz
2020-02-06 16:47               ` Max Reitz
2020-02-06 16:58                 ` Kevin Wolf
2020-02-06 16:57               ` Kevin Wolf
2020-02-06 17:06                 ` Max Reitz
2020-02-06 17:41                   ` Kevin Wolf
2020-01-30 21:44 ` [PATCH v3 10/21] quorum: Implement .bdrv_recurse_can_replace() Max Reitz
2020-02-04  9:37   ` Vladimir Sementsov-Ogievskiy
2020-01-30 21:44 ` [PATCH v3 11/21] block: Use bdrv_recurse_can_replace() Max Reitz
2020-01-30 21:44 ` [PATCH v3 12/21] block: Remove bdrv_recurse_is_first_non_filter() Max Reitz
2020-02-04  9:45   ` Vladimir Sementsov-Ogievskiy
2020-01-30 21:44 ` Max Reitz [this message]
2020-01-30 21:44 ` [PATCH v3 14/21] quorum: Stop marking it as a filter Max Reitz
2020-01-30 21:44 ` [PATCH v3 15/21] iotests: Use complete_and_wait() in 155 Max Reitz
2020-01-30 21:44 ` [PATCH v3 16/21] iotests: Add VM.assert_block_path() Max Reitz
2020-02-04 10:33   ` Vladimir Sementsov-Ogievskiy
2020-02-04 14:09   ` Vladimir Sementsov-Ogievskiy
2020-01-30 21:44 ` [PATCH v3 17/21] iotests/041: Drop superfluous shutdowns Max Reitz
2020-02-04 11:40   ` Vladimir Sementsov-Ogievskiy
2020-01-30 21:44 ` [PATCH v3 18/21] iotests: Resolve TODOs in 041 Max Reitz
2020-02-04  9:54   ` Vladimir Sementsov-Ogievskiy
2020-01-30 21:44 ` [PATCH v3 19/21] iotests: Use self.image_len in TestRepairQuorum Max Reitz
2020-01-30 21:44 ` [PATCH v3 20/21] iotests: Add tests for invalid Quorum @replaces Max Reitz
2020-01-30 21:44 ` [PATCH v3 21/21] iotests: Check that @replaces can replace filters Max Reitz
2020-02-04  9:56   ` Vladimir Sementsov-Ogievskiy

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