Re: [Qemu-devel] [PATCH V19 6/8] add debug event for add-cow

[Stefan Hajnoczi <stefanha@redhat.com>]

On Wed, Jun 05, 2013 at 03:46:43PM +0200, Kevin Wolf wrote:
> Am 30.05.2013 um 12:00 hat Dongxu Wang geschrieben:
> > From: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
> > 
> > Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
> > Signed-off-by: Dongxu Wang <wdongxu@linux.vnet.ibm.com>
> 
> One of these should surely be enough?
> 
> > ---
> >  block/blkdebug.c      | 3 +++
> >  block/block-cache.c   | 4 ++--
> >  include/block/block.h | 3 +++
> >  3 files changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/block/blkdebug.c b/block/blkdebug.c
> > index 71f99e4..2bd6a53 100644
> > --- a/block/blkdebug.c
> > +++ b/block/blkdebug.c
> > @@ -182,6 +182,9 @@ static const char *event_names[BLKDBG_EVENT_MAX] = {
> >      [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",
> >      [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",
> >      [BLKDBG_CLUSTER_FREE]                   = "cluster_free",
> > +
> > +    [BLKDBG_ADDCOW_READ]                    = "add_cow_read",
> > +    [BLKDBG_ADDCOW_WRITE]                   = "add_cow_write",
> >  };
> >  
> >  static int get_event_by_name(const char *name, BlkDebugEvent *event)
> > diff --git a/block/block-cache.c b/block/block-cache.c
> > index f5d75d1..454269c 100644
> > --- a/block/block-cache.c
> > +++ b/block/block-cache.c
> > @@ -125,7 +125,7 @@ static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i)
> >      } else if (c->table_type == BLOCK_TABLE_L2) {
> >          BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
> >      } else if (c->table_type == BLOCK_TABLE_BITMAP) {
> > -        BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
> > +        BLKDBG_EVENT(bs->file, BLKDBG_ADDCOW_WRITE);
> >      }
> >  
> >      ret = bdrv_pwrite(bs->file, c->entries[i].offset,
> > @@ -260,7 +260,7 @@ static int block_cache_do_get(BlockDriverState *bs, BlockCache *c,
> >          if (c->table_type == BLOCK_TABLE_L2) {
> >              BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
> >          } else if (c->table_type == BLOCK_TABLE_BITMAP) {
> > -            BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
> > +            BLKDBG_EVENT(bs->file, BLKDBG_ADDCOW_READ);
> >          }
> 
> Doesn't this break qcow2 test cases that don't get the
> BLKDBG_COW_READ/WRITE events any more now?

This event is only raised for BLKDBG_TABLE_BITMAP, which is new for
add-cow only.  qcow2 only uses L2 and refcount table types, not bitmap.