On 05/27/2014 06:11 PM, Fam Zheng wrote: > On Tue, 05/27 16:54, chai wen wrote: >> If we want to track dirty blocks using dirty_maps on a BlockDriverState >> when doing live block-migration, its correspoding 'BlkMigDevState' should be >> add to block_mig_state.bmds_list firstly for subsequent processing. >> Otherwise set_dirty_tracking will do nothing on an empty list than allocating >> dirty_bitmaps for them. >> >> And what's the worse, bdrv_get_dirty_count will access the >> bmds->dirty_maps directly, there could be a segfault as the reasons >> above. >> >> Signed-off-by: chai wen <chaiw.f...@cn.fujitsu.com> >> --- >> block-migration.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/block-migration.c b/block-migration.c >> index 56951e0..43203aa 100644 >> --- a/block-migration.c >> +++ b/block-migration.c >> @@ -626,6 +626,7 @@ 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); > > Thanks for spotting this! > > I reverted the order of init_blk_migration and set_dirty_tracking in commit > b8afb520e (block: Handle error of bdrv_getlength in bdrv_create_dirty_bitmap) > incorrectly, thought that in this way, no clean up is needed if > set_dirty_tracking fails. > > But by looking at savevm.c:qemu_savevm_state() we can see that > qemu_savevm_state_cancel() will do the clean up automatically, so this fix is > valid. > > Reviewed-by: Fam Zheng <f...@redhat.com>
Yeah, thank you for the review. thanks chai wen > >> >> /* start track dirty blocks */ >> ret = set_dirty_tracking(); >> @@ -635,7 +636,6 @@ static int block_save_setup(QEMUFile *f, void *opaque) >> return ret; >> } >> >> - init_blk_migration(f); >> >> qemu_mutex_unlock_iothread(); >> >> -- >> 1.7.1 >> >> > . > -- Regards Chai Wen
