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authorKevin Wolf <kwolf@redhat.com>2019-07-22 17:44:27 +0200
committerKevin Wolf <kwolf@redhat.com>2019-08-16 10:25:16 +0200
commitd2da5e288a2e71e82866c8fdefd41b5727300124 (patch)
treedc1fe8c9ec21fd5f96c92f348e4c87698b416b6f /block
parent421919d76b1755e1f9478f85cb71829ca5150ade (diff)
mirror: Keep mirror_top_bs drained after dropping permissions
mirror_top_bs is currently implicitly drained through its connection to the source or the target node. However, the drain section for target_bs ends early after moving mirror_top_bs from src to target_bs, so that requests can already be restarted while mirror_top_bs is still present in the chain, but has dropped all permissions and therefore runs into an assertion failure like this: qemu-system-x86_64: block/io.c:1634: bdrv_co_write_req_prepare: Assertion `child->perm & BLK_PERM_WRITE' failed. Keep mirror_top_bs drained until all graph changes have completed. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/mirror.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/block/mirror.c b/block/mirror.c
index 9f5c59ece1..642d6570cc 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -656,7 +656,10 @@ static int mirror_exit_common(Job *job)
s->target = NULL;
/* We don't access the source any more. Dropping any WRITE/RESIZE is
- * required before it could become a backing file of target_bs. */
+ * required before it could become a backing file of target_bs. Not having
+ * these permissions any more means that we can't allow any new requests on
+ * mirror_top_bs from now on, so keep it drained. */
+ bdrv_drained_begin(mirror_top_bs);
bs_opaque->stop = true;
bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
&error_abort);
@@ -724,6 +727,7 @@ static int mirror_exit_common(Job *job)
bs_opaque->job = NULL;
bdrv_drained_end(src);
+ bdrv_drained_end(mirror_top_bs);
s->in_drain = false;
bdrv_unref(mirror_top_bs);
bdrv_unref(src);