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From 1e0582ad34e77a060e2067a35992979c9eae82c9 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 13 Mar 2020 12:34:31 +0000
Subject: [PATCH 11/20] block: bdrv_reopen() with backing file in different
AioContext
RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20200313123439.10548-6-kwolf@redhat.com>
Patchwork-id: 94282
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH v2 05/13] block: bdrv_reopen() with backing file in different AioContext
Bugzilla: 1790482 1805143
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Daniel P. Berrange <berrange@redhat.com>
RH-Acked-by: Peter Krempa <pkrempa@redhat.com>
This patch allows bdrv_reopen() (and therefore the x-blockdev-reopen QMP
command) to attach a node as the new backing file even if the node is in
a different AioContext than the parent if one of both nodes can be moved
to the AioContext of the other node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Message-Id: <20200306141413.30705-3-kwolf@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 1de6b45fb5c1489b450df7d1a4c692bba9678ce6)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
block.c | 32 ++++++++++++++++++++++++++------
tests/qemu-iotests/245 | 8 +++-----
2 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/block.c b/block.c
index a744bb5..39e4647 100644
--- a/block.c
+++ b/block.c
@@ -3749,6 +3749,29 @@ static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
*shared = cumulative_shared_perms;
}
+static bool bdrv_reopen_can_attach(BlockDriverState *parent,
+ BdrvChild *child,
+ BlockDriverState *new_child,
+ Error **errp)
+{
+ AioContext *parent_ctx = bdrv_get_aio_context(parent);
+ AioContext *child_ctx = bdrv_get_aio_context(new_child);
+ GSList *ignore;
+ bool ret;
+
+ ignore = g_slist_prepend(NULL, child);
+ ret = bdrv_can_set_aio_context(new_child, parent_ctx, &ignore, NULL);
+ g_slist_free(ignore);
+ if (ret) {
+ return ret;
+ }
+
+ ignore = g_slist_prepend(NULL, child);
+ ret = bdrv_can_set_aio_context(parent, child_ctx, &ignore, errp);
+ g_slist_free(ignore);
+ return ret;
+}
+
/*
* Take a BDRVReopenState and check if the value of 'backing' in the
* reopen_state->options QDict is valid or not.
@@ -3800,14 +3823,11 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
}
/*
- * TODO: before removing the x- prefix from x-blockdev-reopen we
- * should move the new backing file into the right AioContext
- * instead of returning an error.
+ * Check AioContext compatibility so that the bdrv_set_backing_hd() call in
+ * bdrv_reopen_commit() won't fail.
*/
if (new_backing_bs) {
- if (bdrv_get_aio_context(new_backing_bs) != bdrv_get_aio_context(bs)) {
- error_setg(errp, "Cannot use a new backing file "
- "with a different AioContext");
+ if (!bdrv_reopen_can_attach(bs, bs->backing, new_backing_bs, errp)) {
return -EINVAL;
}
}
diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245
index f69c2fa..919131d 100644
--- a/tests/qemu-iotests/245
+++ b/tests/qemu-iotests/245
@@ -1013,18 +1013,16 @@ class TestBlockdevReopen(iotests.QMPTestCase):
# neither of them can switch to the other AioContext
def test_iothreads_error(self):
self.run_test_iothreads('iothread0', 'iothread1',
- "Cannot use a new backing file with a different AioContext")
+ "Cannot change iothread of active block backend")
def test_iothreads_compatible_users(self):
self.run_test_iothreads('iothread0', 'iothread0')
def test_iothreads_switch_backing(self):
- self.run_test_iothreads('iothread0', None,
- "Cannot use a new backing file with a different AioContext")
+ self.run_test_iothreads('iothread0', None)
def test_iothreads_switch_overlay(self):
- self.run_test_iothreads(None, 'iothread0',
- "Cannot use a new backing file with a different AioContext")
+ self.run_test_iothreads(None, 'iothread0')
if __name__ == '__main__':
iotests.main(supported_fmts=["qcow2"],
--
1.8.3.1