block/backup: loosen restriction on readonly bitmaps

With the "never" sync policy, we actually can utilize readonly bitmaps
now. Loosen the check at the QMP level, and tighten it based on
provided arguments down at the job creation level instead.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190709232550.10724-19-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

diff --git a/block/backup.c b/block/backup.c
index 2be570c0bfd6b244a76ad7cff815724e499a07a3..f8309be01b3600a7d9ca0859b2c5360e74e375e2 100644 (file)
--- a/block/backup.c
+++ b/block/backup.c
@@ -617,6 +617,12 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
             return NULL;
         }
 
+        /* If we need to write to this bitmap, check that we can: */
+        if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
+            bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) {
+            return NULL;
+        }
+
         /* Create a new bitmap, and freeze/disable this one. */
         if (bdrv_dirty_bitmap_create_successor(bs, sync_bitmap, errp) < 0) {
             return NULL;

diff --git a/blockdev.c b/blockdev.c
index 985b6cd75c0ff9cec5a24b640310a8d9e25a33d9..a44ab1f709e22e31d145f7ac87b943dfcb81f23b 100644 (file)
--- a/blockdev.c
+++ b/blockdev.c
@@ -3491,7 +3491,7 @@ static BlockJob *do_backup_common(BackupCommon *backup,
                        "when providing a bitmap");
             return NULL;
         }
-        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_DEFAULT, errp)) {
+        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
             return NULL;
         }
     }