From: John Snow Date: Tue, 12 Mar 2019 16:05:48 +0000 (-0400) Subject: block/dirty-bitmap: explicitly lock bitmaps with successors X-Git-Tag: v4.0.0-rc0~24^2~16 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=21d2376f264bcaa1692bd71ab1f99b9b0ff5afbf;p=thirdparty%2Fqemu.git 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 Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Message-id: 20190223000614.13894-7-jsnow@redhat.com Signed-off-by: John Snow --- diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index fa411f9e87d..a4951780e29 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; } @@ -323,6 +322,7 @@ 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; @@ -352,6 +352,7 @@ 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;