| Message ID | 1401853657-31014-1-git-send-email-chaiw.fnst@cn.fujitsu.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Jun 04, 2014 at 11:47:37AM +0800, chai wen wrote: > > 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 <famz@redhat.com> > Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com> > --- > block-migration.c | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
On 06/04/2014 05:23 PM, Stefan Hajnoczi wrote: > On Wed, Jun 04, 2014 at 11:47:37AM +0800, chai wen wrote: >> >> 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 <famz@redhat.com> >> Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com> >> --- >> block-migration.c | 3 +-- >> 1 files changed, 1 insertions(+), 2 deletions(-) > > Thanks, applied to my block tree: > https://github.com/stefanha/qemu/commits/block > OK， thanks for your attention about this fix. :) thanks chai wen > Stefan > . >
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);