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[Qemu-devel] [PATCH 46/79] mirror: Drop permissions on s->target on comp
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 46/79] mirror: Drop permissions on s->target on completion |
Date: |
Mon, 28 Aug 2017 19:14:21 -0500 |
From: Kevin Wolf <address@hidden>
This fixes an assertion failure that was triggered by qemu-iotests 129
on some CI host, while the same test case didn't seem to fail on other
hosts.
Essentially the problem is that the blk_unref(s->target) in
mirror_exit() doesn't necessarily mean that the BlockBackend goes away
immediately. It is possible that the job completion was triggered nested
in mirror_drain(), which looks like this:
BlockBackend *target = s->target;
blk_ref(target);
blk_drain(target);
blk_unref(target);
In this case, the write permissions for s->target are retained until
after blk_drain(), which makes removing mirror_top_bs fail for the
active commit case (can't have a writable backing file in the chain
without the filter driver).
Explicitly dropping the permissions first means that the additional
reference doesn't hurt and the job can complete successfully even if
called from the nested blk_drain().
Cc: address@hidden
Signed-off-by: Kevin Wolf <address@hidden>
Acked-by: Paolo Bonzini <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
(cherry picked from commit 63c8ef289087a225d445319d047501d4fe593687)
Signed-off-by: Michael Roth <address@hidden>
---
block/mirror.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/block/mirror.c b/block/mirror.c
index 2173a2f..4e8f124 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -514,7 +514,12 @@ static void mirror_exit(BlockJob *job, void *opaque)
/* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
* inserting target_bs at s->to_replace, where we might not be able to get
- * these permissions. */
+ * these permissions.
+ *
+ * Note that blk_unref() alone doesn't necessarily drop permissions because
+ * we might be running nested inside mirror_drain(), which takes an extra
+ * reference, so use an explicit blk_set_perm() first. */
+ blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort);
blk_unref(s->target);
s->target = NULL;
--
2.7.4
- [Qemu-devel] [PATCH 34/79] virtio-scsi: Unset hotplug handler when unrealize, (continued)
- [Qemu-devel] [PATCH 34/79] virtio-scsi: Unset hotplug handler when unrealize, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 02/79] dirty-bitmap: Report BlockDirtyInfo.count in bytes, as documented, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 28/79] curl: strengthen assertion in curl_clean_state, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 39/79] blkdebug: Refactor error injection, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 03/79] qemu-img/convert: Always set ret < 0 on error, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 30/79] curl: avoid recursive locking of BDRVCURLState mutex, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 32/79] vvfat: fix qemu-img map and qemu-img convert, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 35/79] e1000e: Fix ICR "Other" causes clear logic, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 33/79] virtio: allow broken device to notify guest, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 31/79] stream: fix crash in stream_start() when block_job_create() fails, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 46/79] mirror: Drop permissions on s->target on completion,
Michael Roth <=
- [Qemu-devel] [PATCH 36/79] s390x/css: catch section mismatch on load, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 43/79] tests: Add coverage for recent block geometry fixes, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 41/79] blkdebug: Simplify override logic, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 44/79] block: Simplify BDRV_BLOCK_RAW recursion, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 49/79] tests: check-qom-proplist: add checks for cmdline-created objects, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 53/79] target/ppc: fix memory leak in kvmppc_is_mem_backend_page_size_ok(), Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 55/79] spapr: fix memory leak in spapr_memory_pre_plug(), Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 37/79] virtio-net: fix wild pointer when remove virtio-net queues, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 38/79] blkdebug: Sanity check block layer guarantees, Michael Roth, 2017/08/28
- [Qemu-devel] [PATCH 52/79] target/ppc: pass const string to kvmppc_is_mem_backend_page_size_ok(), Michael Roth, 2017/08/28