From d6883bc96890dae97757ee8a61aab7f18d9a66de Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Wed, 28 Jun 2017 15:05:10 +0300 Subject: block/dirty-bitmap: add readonly field to BdrvDirtyBitmap It will be needed in following commits for persistent bitmaps. If bitmap is loaded from read-only storage (and we can't mark it "in use" in this storage) corresponding BdrvDirtyBitmap should be read-only. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20170628120530.31251-11-vsementsov@virtuozzo.com Signed-off-by: Max Reitz --- block/dirty-bitmap.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'block/dirty-bitmap.c') diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index a8fe149c4a..17d3068336 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -46,6 +46,12 @@ struct BdrvDirtyBitmap { bool disabled; /* Bitmap is disabled. It ignores all writes to the device */ int active_iterators; /* How many iterators are active */ + bool readonly; /* Bitmap is read-only. This field also + prevents the respective image from being + modified (i.e. blocks writes and discards). + Such operations must fail and both the image + and this bitmap must remain unchanged while + this flag is set. */ QLIST_ENTRY(BdrvDirtyBitmap) list; }; @@ -505,6 +511,7 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, int64_t cur_sector, int64_t nr_sectors) { assert(bdrv_dirty_bitmap_enabled(bitmap)); + assert(!bdrv_dirty_bitmap_readonly(bitmap)); hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); } @@ -521,6 +528,7 @@ void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, int64_t cur_sector, int64_t nr_sectors) { assert(bdrv_dirty_bitmap_enabled(bitmap)); + assert(!bdrv_dirty_bitmap_readonly(bitmap)); hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); } @@ -535,6 +543,7 @@ void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap, void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out) { assert(bdrv_dirty_bitmap_enabled(bitmap)); + assert(!bdrv_dirty_bitmap_readonly(bitmap)); bdrv_dirty_bitmap_lock(bitmap); if (!out) { hbitmap_reset_all(bitmap->bitmap); @@ -551,6 +560,7 @@ void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in) { HBitmap *tmp = bitmap->bitmap; assert(bdrv_dirty_bitmap_enabled(bitmap)); + assert(!bdrv_dirty_bitmap_readonly(bitmap)); bitmap->bitmap = in; hbitmap_free(tmp); } @@ -613,6 +623,7 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, if (!bdrv_dirty_bitmap_enabled(bitmap)) { continue; } + assert(!bdrv_dirty_bitmap_readonly(bitmap)); hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); } bdrv_dirty_bitmaps_unlock(bs); @@ -635,3 +646,28 @@ int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap) { return hbitmap_count(bitmap->meta); } + +bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap) +{ + return bitmap->readonly; +} + +/* Called with BQL taken. */ +void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap, bool value) +{ + qemu_mutex_lock(bitmap->mutex); + bitmap->readonly = value; + qemu_mutex_unlock(bitmap->mutex); +} + +bool bdrv_has_readonly_bitmaps(BlockDriverState *bs) +{ + BdrvDirtyBitmap *bm; + QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { + if (bm->readonly) { + return true; + } + } + + return false; +} -- cgit v1.2.1