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[Qemu-devel] [PATCH v3 03/21] mirror: Error out when a BDS would get two
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v3 03/21] mirror: Error out when a BDS would get two BBs |
Date: |
Fri, 4 Dec 2015 14:35:06 +0100 |
bdrv_replace_in_backing_chain() asserts that not both old and new
BlockDdriverState have a BlockBackend attached to them because both
would have to end up pointing to the new BDS and we don't support more
than one BB per BDS yet.
Before we can safely allow references to existing nodes as backing
files, we need to make sure that even if a backing file has a BB on it,
this doesn't crash qemu.
There are probably also some cases with the 'replaces' option set where
drive-mirror could fail this assertion today. They are fixed with this
error check as well.
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
---
block/mirror.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/block/mirror.c b/block/mirror.c
index 0e8f556..8e3f524 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -18,6 +18,7 @@
#include "qapi/qmp/qerror.h"
#include "qemu/ratelimit.h"
#include "qemu/bitmap.h"
+#include "qemu/error-report.h"
#define SLICE_TIME 100000000ULL /* ns */
#define MAX_IN_FLIGHT 16
@@ -370,11 +371,22 @@ static void mirror_exit(BlockJob *job, void *opaque)
if (s->to_replace) {
to_replace = s->to_replace;
}
+
+ /* This was checked in mirror_start_job(), but meanwhile one of the
+ * nodes could have been newly attached to a BlockBackend. */
+ if (to_replace->blk && s->target->blk) {
+ error_report("block job: Can't create node with two
BlockBackends");
+ data->ret = -EINVAL;
+ goto out;
+ }
+
if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) {
bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL);
}
bdrv_replace_in_backing_chain(to_replace, s->target);
}
+
+out:
if (s->to_replace) {
bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
error_free(s->replace_blocker);
@@ -705,6 +717,7 @@ static void mirror_start_job(BlockDriverState *bs,
BlockDriverState *target,
bool is_none_mode, BlockDriverState *base)
{
MirrorBlockJob *s;
+ BlockDriverState *replaced_bs;
if (granularity == 0) {
granularity = bdrv_get_default_bitmap_granularity(target);
@@ -728,6 +741,21 @@ static void mirror_start_job(BlockDriverState *bs,
BlockDriverState *target,
buf_size = DEFAULT_MIRROR_BUF_SIZE;
}
+ /* We can't support this case as long as the block layer can't handle
+ * multiple BlockBackends per BlockDriverState. */
+ if (replaces) {
+ replaced_bs = bdrv_lookup_bs(replaces, replaces, errp);
+ if (replaced_bs == NULL) {
+ return;
+ }
+ } else {
+ replaced_bs = bs;
+ }
+ if (replaced_bs->blk && target->blk) {
+ error_setg(errp, "Can't create node with two BlockBackends");
+ return;
+ }
+
s = block_job_create(driver, bs, speed, cb, opaque, errp);
if (!s) {
return;
--
1.8.3.1
- [Qemu-devel] [PATCH v3 00/21] block: Cache mode for children etc., Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 02/21] block: Fix reopen with semantically overlapping options, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 01/21] qcow2: Add .bdrv_join_options callback, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 03/21] mirror: Error out when a BDS would get two BBs,
Kevin Wolf <=
- [Qemu-devel] [PATCH v3 06/21] block: Exclude nested options only for children in append_open_options(), Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 04/21] block: Allow references for backing files, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 07/21] block: Pass driver-specific options to .bdrv_refresh_filename(), Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 05/21] block: Consider all block layer options in append_open_options, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 09/21] block: Allow specifying child options in reopen, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 08/21] block: Keep "driver" in bs->options, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 10/21] block: reopen: Document option precedence and refactor accordingly, Kevin Wolf, 2015/12/04
- [Qemu-devel] [PATCH v3 11/21] block: Add infrastructure for option inheritance, Kevin Wolf, 2015/12/04