[libvirt] [PATCH v3 06/10] block/dirty-bitmap: explicitly lock bitmaps with successors
Instead of implying a user_locked/busy status, make it explicit.
Now, bitmaps in use by migration, NBD or backup operations
are all treated the same way with the same code paths.
Signed-off-by: John Snow <jsnow(a)redhat.com>
Reviewed-by: Eric Blake <eblake(a)redhat.com>
---
block/dirty-bitmap.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 976831e765..d92a269753 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -50,7 +50,7 @@ struct BdrvDirtyBitmap {
HBitmap *meta; /* Meta dirty bitmap */
bool qmp_locked; /* Bitmap is locked, it can't be modified
through QMP */
- BdrvDirtyBitmap *successor; /* Anonymous child; implies user_locked state */
+ BdrvDirtyBitmap *successor; /* Anonymous child, if any. */
char *name; /* Optional non-empty unique ID */
int64_t size; /* Size of the bitmap, in bytes */
bool disabled; /* Bitmap is disabled. It ignores all writes to
@@ -188,10 +188,8 @@ bool bdrv_dirty_bitmap_has_successor(BdrvDirtyBitmap *bitmap)
return bitmap->successor;
}
-/* Both conditions disallow user-modification via QMP. */
bool bdrv_dirty_bitmap_user_locked(BdrvDirtyBitmap *bitmap) {
- return bdrv_dirty_bitmap_has_successor(bitmap) ||
- bdrv_dirty_bitmap_qmp_locked(bitmap);
+ return bdrv_dirty_bitmap_qmp_locked(bitmap);
}
void bdrv_dirty_bitmap_set_qmp_locked(BdrvDirtyBitmap *bitmap, bool qmp_locked)
@@ -267,8 +265,9 @@ int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
child->disabled = bitmap->disabled;
bitmap->disabled = true;
- /* Install the successor and freeze the parent */
+ /* Install the successor and lock the parent */
bitmap->successor = child;
+ bitmap->qmp_locked = true;
return 0;
}
@@ -322,6 +321,7 @@ BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs,
bitmap->successor = NULL;
successor->persistent = bitmap->persistent;
bitmap->persistent = false;
+ bitmap->qmp_locked = false;
bdrv_release_dirty_bitmap(bs, bitmap);
return successor;
@@ -351,6 +351,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState
*bs,
}
parent->disabled = successor->disabled;
+ parent->qmp_locked = false;
bdrv_release_dirty_bitmap_locked(successor);
parent->successor = NULL;
--
2.17.2