Re: [PATCH for 9.0] migration: Skip only empty block devices

[Cédric Le Goater]

On 3/12/24 13:04, Cédric Le Goater wrote:

The block .save_setup() handler calls a helper routine
init_blk_migration() which builds a list of block devices to take into
account for migration. When one device is found to be empty (sectors
== 0), the loop exits and all the remaining devices are ignored. This
is a regression introduced when bdrv_iterate() was removed.

Change that by skipping only empty devices.

Cc: Markus Armbruster <arm...@redhat.com>
Suggested: Kevin Wolf <kw...@redhat.com>

That's better :

Suggested-by: Kevin Wolf <kw...@redhat.com>

Sorry for the noise,

C.

Fixes: fea68bb6e9fa ("block: Eliminate bdrv_iterate(), use bdrv_next()")
Signed-off-by: Cédric Le Goater <c...@redhat.com>
---
  migration/block.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/migration/block.c b/migration/block.c
index 
8c6ebafacc1ffe930d1d4f19d968817b14852c69..2b9054889ad2ba739828594c50cf047703757e96
 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -402,7 +402,10 @@ static int init_blk_migration(QEMUFile *f)
          }

sectors = bdrv_nb_sectors(bs);

-        if (sectors <= 0) {
+        if (sectors == 0) {
+            continue;
+        }
+        if (sectors < 0) {
              ret = sectors;
              bdrv_next_cleanup(&it);
              goto out;