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dirty-bitmap: fix double lock on bitmap enabling 

Bitmap lock/unlock were added to bdrv_enable_dirty_bitmap in
8b1402ce80, but some places were not updated correspondingly, which
leads to trying to take this lock twice, which is dead-lock. Fix this.

Actually, iotest 199 (about dirty bitmap postcopy migration) is broken
now, and this fixes it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180625165745.25259-3-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2018-07-04 02:12:49 -04:00 committed by John Snow
parent 92bcea40d3
commit 58f72b965e
2 changed files with 4 additions and 3 deletions
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3
block/dirty-bitmap.c
View File

@ -250,8 +250,9 @@ void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
/* Called with BQL taken. */
void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap)
{
assert(bitmap->mutex == bitmap->successor->mutex);
qemu_mutex_lock(bitmap->mutex);
bdrv_enable_dirty_bitmap(bitmap->successor);
bdrv_enable_dirty_bitmap_locked(bitmap->successor);
qemu_mutex_unlock(bitmap->mutex);
}

4
migration/block-dirty-bitmap.c
View File

@ -511,7 +511,7 @@ void dirty_bitmap_mig_before_vm_start(void)
DirtyBitmapLoadBitmapState *b = item->data;
if (b->migrated) {
bdrv_enable_dirty_bitmap(b->bitmap);
bdrv_enable_dirty_bitmap_locked(b->bitmap);
} else {
bdrv_dirty_bitmap_enable_successor(b->bitmap);
}
@ -547,7 +547,7 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DirtyBitmapLoadState *s)
if (enabled_bitmaps == NULL) {
/* in postcopy */
bdrv_reclaim_dirty_bitmap_locked(s->bs, s->bitmap, &error_abort);
bdrv_enable_dirty_bitmap(s->bitmap);
bdrv_enable_dirty_bitmap_locked(s->bitmap);
} else {
/* target not started, successor must be empty */
int64_t count = bdrv_get_dirty_count(s->bitmap);