diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/dirty-bitmap.c | 36 | ||||
| -rw-r--r-- | block/qcow2-bitmap.c | 16 | ||||
| -rw-r--r-- | block/qcow2.c | 65 |
3 files changed, 93 insertions, 24 deletions
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index 9b9ebd7142..89fd1d7f8b 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -55,6 +55,10 @@ struct BdrvDirtyBitmap { and this bitmap must remain unchanged while this flag is set. */ bool persistent; /* bitmap must be saved to owner disk image */ + bool migration; /* Bitmap is selected for migration, it should + not be stored on the next inactivation + (persistent flag doesn't matter until next + invalidation).*/ QLIST_ENTRY(BdrvDirtyBitmap) list; }; @@ -390,26 +394,6 @@ void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs) } /** - * Release all persistent dirty bitmaps attached to a BDS (for use in - * bdrv_inactivate_recurse()). - * There must not be any frozen bitmaps attached. - * This function does not remove persistent bitmaps from the storage. - * Called with BQL taken. - */ -void bdrv_release_persistent_dirty_bitmaps(BlockDriverState *bs) -{ - BdrvDirtyBitmap *bm, *next; - - bdrv_dirty_bitmaps_lock(bs); - QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { - if (bdrv_dirty_bitmap_get_persistance(bm)) { - bdrv_release_dirty_bitmap_locked(bm); - } - } - bdrv_dirty_bitmaps_unlock(bs); -} - -/** * Remove persistent dirty bitmap from the storage if it exists. * Absence of bitmap is not an error, because we have the following scenario: * BdrvDirtyBitmap can have .persistent = true but not yet saved and have no @@ -761,16 +745,24 @@ void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap, bool persistent) qemu_mutex_unlock(bitmap->mutex); } +/* Called with BQL taken. */ +void bdrv_dirty_bitmap_set_migration(BdrvDirtyBitmap *bitmap, bool migration) +{ + qemu_mutex_lock(bitmap->mutex); + bitmap->migration = migration; + qemu_mutex_unlock(bitmap->mutex); +} + bool bdrv_dirty_bitmap_get_persistance(BdrvDirtyBitmap *bitmap) { - return bitmap->persistent; + return bitmap->persistent && !bitmap->migration; } bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs) { BdrvDirtyBitmap *bm; QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { - if (bm->persistent && !bm->readonly) { + if (bm->persistent && !bm->readonly && !bm->migration) { return true; } } diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index ba978ad2aa..b5f1b3563d 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1418,6 +1418,22 @@ void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp) g_free(tb); } + QSIMPLEQ_FOREACH(bm, bm_list, entry) { + /* For safety, we remove bitmap after storing. + * We may be here in two cases: + * 1. bdrv_close. It's ok to drop bitmap. + * 2. inactivation. It means migration without 'dirty-bitmaps' + * capability, so bitmaps are not marked with + * BdrvDirtyBitmap.migration flags. It's not bad to drop them too, + * and reload on invalidation. + */ + if (bm->dirty_bitmap == NULL) { + continue; + } + + bdrv_release_dirty_bitmap(bs, bm->dirty_bitmap); + } + bitmap_list_free(bm_list); return; diff --git a/block/qcow2.c b/block/qcow2.c index 3110bb0e20..30689b7688 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1491,8 +1491,69 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, s->autoclear_features &= QCOW2_AUTOCLEAR_MASK; } - if (qcow2_load_dirty_bitmaps(bs, &local_err)) { - update_header = false; + /* == Handle persistent dirty bitmaps == + * + * We want load dirty bitmaps in three cases: + * + * 1. Normal open of the disk in active mode, not related to invalidation + * after migration. + * + * 2. Invalidation of the target vm after pre-copy phase of migration, if + * bitmaps are _not_ migrating through migration channel, i.e. + * 'dirty-bitmaps' capability is disabled. + * + * 3. Invalidation of source vm after failed or canceled migration. + * This is a very interesting case. There are two possible types of + * bitmaps: + * + * A. Stored on inactivation and removed. They should be loaded from the + * image. + * + * B. Not stored: not-persistent bitmaps and bitmaps, migrated through + * the migration channel (with dirty-bitmaps capability). + * + * On the other hand, there are two possible sub-cases: + * + * 3.1 disk was changed by somebody else while were inactive. In this + * case all in-RAM dirty bitmaps (both persistent and not) are + * definitely invalid. And we don't have any method to determine + * this. + * + * Simple and safe thing is to just drop all the bitmaps of type B on + * inactivation. But in this case we lose bitmaps in valid 4.2 case. + * + * On the other hand, resuming source vm, if disk was already changed + * is a bad thing anyway: not only bitmaps, the whole vm state is + * out of sync with disk. + * + * This means, that user or management tool, who for some reason + * decided to resume source vm, after disk was already changed by + * target vm, should at least drop all dirty bitmaps by hand. + * + * So, we can ignore this case for now, but TODO: "generation" + * extension for qcow2, to determine, that image was changed after + * last inactivation. And if it is changed, we will drop (or at least + * mark as 'invalid' all the bitmaps of type B, both persistent + * and not). + * + * 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved + * to disk ('dirty-bitmaps' capability disabled), or not saved + * ('dirty-bitmaps' capability enabled), but we don't need to care + * of: let's load bitmaps as always: stored bitmaps will be loaded, + * and not stored has flag IN_USE=1 in the image and will be skipped + * on loading. + * + * One remaining possible case when we don't want load bitmaps: + * + * 4. Open disk in inactive mode in target vm (bitmaps are migrating or + * will be loaded on invalidation, no needs try loading them before) + */ + + if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) { + /* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */ + bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err); + + update_header = update_header && !header_updated; } if (local_err != NULL) { error_propagate(errp, local_err); |