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[Qemu-devel] [PULL 5/7] block-backend: Defer shared_perm tightening migr
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 5/7] block-backend: Defer shared_perm tightening migration completion |
Date: |
Tue, 15 Aug 2017 10:09:05 -0500 |
From: Fam Zheng <address@hidden>
As in the case of nbd_export_new(), bdrv_invalidate_cache() can be
called when migration is still in progress. In this case we are not
ready to tighten the shared permissions fenced by blk->disable_perm.
Defer to a VM state change handler.
Signed-off-by: Fam Zheng <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Eric Blake <address@hidden>
---
block/block-backend.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/block/block-backend.c b/block/block-backend.c
index 968438c149..e9798e897d 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -20,6 +20,7 @@
#include "qapi-event.h"
#include "qemu/id.h"
#include "trace.h"
+#include "migration/misc.h"
/* Number of coroutines to reserve per attached device model */
#define COROUTINE_POOL_RESERVATION 64
@@ -68,6 +69,7 @@ struct BlockBackend {
NotifierList remove_bs_notifiers, insert_bs_notifiers;
int quiesce_counter;
+ VMChangeStateEntry *vmsh;
};
typedef struct BlockBackendAIOCB {
@@ -129,6 +131,23 @@ static const char *blk_root_get_name(BdrvChild *child)
return blk_name(child->opaque);
}
+static void blk_vm_state_changed(void *opaque, int running, RunState state)
+{
+ Error *local_err = NULL;
+ BlockBackend *blk = opaque;
+
+ if (state == RUN_STATE_INMIGRATE) {
+ return;
+ }
+
+ qemu_del_vm_change_state_handler(blk->vmsh);
+ blk->vmsh = NULL;
+ blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ }
+}
+
/*
* Notifies the user of the BlockBackend that migration has completed. qdev
* devices can tighten their permissions in response (specifically revoke
@@ -147,6 +166,24 @@ static void blk_root_activate(BdrvChild *child, Error
**errp)
blk->disable_perm = false;
+ blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ blk->disable_perm = true;
+ return;
+ }
+
+ if (runstate_check(RUN_STATE_INMIGRATE)) {
+ /* Activation can happen when migration process is still active, for
+ * example when nbd_server_add is called during non-shared storage
+ * migration. Defer the shared_perm update to migration completion. */
+ if (!blk->vmsh) {
+ blk->vmsh = qemu_add_vm_change_state_handler(blk_vm_state_changed,
+ blk);
+ }
+ return;
+ }
+
blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
if (local_err) {
error_propagate(errp, local_err);
@@ -291,6 +328,10 @@ static void blk_delete(BlockBackend *blk)
if (blk->root) {
blk_remove_bs(blk);
}
+ if (blk->vmsh) {
+ qemu_del_vm_change_state_handler(blk->vmsh);
+ blk->vmsh = NULL;
+ }
assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers));
assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers));
QTAILQ_REMOVE(&block_backends, blk, link);
--
2.13.5
- [Qemu-devel] [PULL for 2.10-rc3 0/7] NBD changes for 2.10-rc3, Eric Blake, 2017/08/15
- [Qemu-devel] [PULL 1/7] nbd: Fix trace message for disconnect, Eric Blake, 2017/08/15
- [Qemu-devel] [PULL 2/7] qemu-iotests: step clock after each test iteration, Eric Blake, 2017/08/15
- [Qemu-devel] [PULL 3/7] stubs: Add vm state change handler stubs, Eric Blake, 2017/08/15
- [Qemu-devel] [PULL 5/7] block-backend: Defer shared_perm tightening migration completion,
Eric Blake <=
- [Qemu-devel] [PULL 4/7] nbd: Fix order of bdrv_set_perm and bdrv_invalidate_cache, Eric Blake, 2017/08/15
- [Qemu-devel] [PULL 7/7] nbd-client: Fix regression when server sends garbage, Eric Blake, 2017/08/15
- Re: [Qemu-devel] [PULL 7/7] nbd-client: Fix regression when server sends garbage, Vladimir Sementsov-Ogievskiy, 2017/08/21