51 lines
2.0 KiB
Diff
51 lines
2.0 KiB
Diff
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Mon, 22 Jul 2019 17:44:27 +0200
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Subject: mirror: Keep mirror_top_bs drained after dropping permissions
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Git-commit: d2da5e288a2e71e82866c8fdefd41b5727300124
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mirror_top_bs is currently implicitly drained through its connection to
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the source or the target node. However, the drain section for target_bs
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ends early after moving mirror_top_bs from src to target_bs, so that
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requests can already be restarted while mirror_top_bs is still present
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in the chain, but has dropped all permissions and therefore runs into an
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assertion failure like this:
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qemu-system-x86_64: block/io.c:1634: bdrv_co_write_req_prepare:
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Assertion `child->perm & BLK_PERM_WRITE' failed.
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Keep mirror_top_bs drained until all graph changes have completed.
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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---
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block/mirror.c | 6 +++++-
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1 file changed, 5 insertions(+), 1 deletion(-)
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diff --git a/block/mirror.c b/block/mirror.c
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index 9f5c59ece1df391babc4461f63cb..642d6570cc97e1239b119a46c457 100644
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--- a/block/mirror.c
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+++ b/block/mirror.c
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@@ -656,7 +656,10 @@ static int mirror_exit_common(Job *job)
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s->target = NULL;
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/* We don't access the source any more. Dropping any WRITE/RESIZE is
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- * required before it could become a backing file of target_bs. */
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+ * required before it could become a backing file of target_bs. Not having
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+ * these permissions any more means that we can't allow any new requests on
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+ * mirror_top_bs from now on, so keep it drained. */
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+ bdrv_drained_begin(mirror_top_bs);
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bs_opaque->stop = true;
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bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
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&error_abort);
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@@ -724,6 +727,7 @@ static int mirror_exit_common(Job *job)
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bs_opaque->job = NULL;
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bdrv_drained_end(src);
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+ bdrv_drained_end(mirror_top_bs);
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s->in_drain = false;
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bdrv_unref(mirror_top_bs);
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bdrv_unref(src);
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