From: chai wen <chaiw.f...@cn.fujitsu.com>
The function init_blk_migration is better to be called before
set_dirty_tracking as the reasons below.
If we want to track dirty blocks via dirty_maps on a BlockDriverState
when doing live block-migration, its correspoding 'BlkMigDevState' should be
added to block_mig_state.bmds_list first for subsequent processing.
Otherwise set_dirty_tracking will do nothing on an empty list than allocating
dirty_bitmaps for them. And bdrv_get_dirty_count will access the
bmds->dirty_maps directly, then there would be a segfault triggered.
If the set_dirty_tracking fails, qemu_savevm_state_cancel will handle
the cleanup of init_blk_migration automatically.
Reviewed-by: Fam Zheng <f...@redhat.com>
Signed-off-by: chai wen <chaiw.f...@cn.fujitsu.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block-migration.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/block-migration.c b/block-migration.c
index 1656270..25a0388 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -629,6 +629,7 @@ static int block_save_setup(QEMUFile *f, void *opaque)
block_mig_state.submitted, block_mig_state.transferred);
qemu_mutex_lock_iothread();
+ init_blk_migration(f);
/* start track dirty blocks */
ret = set_dirty_tracking();
@@ -638,8 +639,6 @@ static int block_save_setup(QEMUFile *f, void *opaque)
return ret;
}
- init_blk_migration(f);
-
qemu_mutex_unlock_iothread();
ret = flush_blks(f);
--
1.9.3
