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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@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190223000614.13894-7-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
John Snow 2019-03-12 12:05:48 -04:00
parent 3b78a92776
commit 21d2376f26
1 changed files with 6 additions and 5 deletions
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11
block/dirty-bitmap.c
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@ -50,7 +50,7 @@ struct BdrvDirtyBitmap {
HBitmap *meta; /* Meta dirty bitmap */ HBitmap *meta; /* Meta dirty bitmap */
bool qmp_locked; /* Bitmap is locked, it can't be modified bool qmp_locked; /* Bitmap is locked, it can't be modified
through QMP */ through QMP */
BdrvDirtyBitmap *successor; /* Anonymous child; implies user_locked state */ BdrvDirtyBitmap *successor; /* Anonymous child, if any. */
char *name; /* Optional non-empty unique ID */ char *name; /* Optional non-empty unique ID */
int64_t size; /* Size of the bitmap, in bytes */ int64_t size; /* Size of the bitmap, in bytes */
bool disabled; /* Bitmap is disabled. It ignores all writes to 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; return bitmap->successor;
} }
/* Both conditions disallow user-modification via QMP. */
bool bdrv_dirty_bitmap_user_locked(BdrvDirtyBitmap *bitmap) { bool bdrv_dirty_bitmap_user_locked(BdrvDirtyBitmap *bitmap) {
return bdrv_dirty_bitmap_has_successor(bitmap) || return bdrv_dirty_bitmap_qmp_locked(bitmap);
bdrv_dirty_bitmap_qmp_locked(bitmap);
} }
void bdrv_dirty_bitmap_set_qmp_locked(BdrvDirtyBitmap *bitmap, bool qmp_locked) 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; child->disabled = bitmap->disabled;
bitmap->disabled = true; bitmap->disabled = true;
/* Install the successor and freeze the parent */ /* Install the successor and lock the parent */
bitmap->successor = child; bitmap->successor = child;
bitmap->qmp_locked = true;
return 0; return 0;
} }
@ -323,6 +322,7 @@ BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs,
bitmap->successor = NULL; bitmap->successor = NULL;
successor->persistent = bitmap->persistent; successor->persistent = bitmap->persistent;
bitmap->persistent = false; bitmap->persistent = false;
bitmap->qmp_locked = false;
bdrv_release_dirty_bitmap(bs, bitmap); bdrv_release_dirty_bitmap(bs, bitmap);
return successor; return successor;
@ -352,6 +352,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,
} }
parent->disabled = successor->disabled; parent->disabled = successor->disabled;
parent->qmp_locked = false;
bdrv_release_dirty_bitmap_locked(successor); bdrv_release_dirty_bitmap_locked(successor);
parent->successor = NULL; parent->successor = NULL;