From 5f7772c4d0cf32f4e779fcd5a69ae4dae24aeebf Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 15 Aug 2017 21:07:39 +0800 Subject: block-backend: Defer shared_perm tightening migration completion 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 Message-Id: <20170815130740.31229-4-famz@redhat.com> Signed-off-by: Eric Blake --- 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); -- cgit v1.2.1