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authorVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>2018-10-29 16:23:17 -0400
committerJohn Snow <jsnow@redhat.com>2018-10-29 16:23:17 -0400
commit9c98f145dfb994e1e9d68a4d606ee5693891280d (patch)
treeba116539e76c0468bd50c15925cf1a3cf819b6f6 /block/dirty-bitmap.c
parentd1dde7149e376d72b422a529ec4bf3ed47f3ba30 (diff)
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dirty-bitmaps: clean-up bitmaps loading and migration logic
This patch aims to bring the following behavior: 1. We don't load bitmaps, when started in inactive mode. It's the case of incoming migration. In this case we wait for bitmaps migration through migration channel (if 'dirty-bitmaps' capability is enabled) or for invalidation (to load bitmaps from the image). 2. We don't remove persistent bitmaps on inactivation. Instead, we only remove bitmaps after storing. This is the only way to restore bitmaps, if we decided to resume source after [failed] migration with 'dirty-bitmaps' capability enabled (which means, that bitmaps were not stored). 3. We load bitmaps on open and any invalidation, it's ok for all cases: - normal open - migration target invalidation with dirty-bitmaps capability (bitmaps are migrating through migration channel, the are not stored, so they should have IN_USE flag set and will be skipped when loading. However, it would fail if bitmaps are read-only[1]) - migration target invalidation without dirty-bitmaps capability (normal load of the bitmaps, if migrated with shared storage) - source invalidation with dirty-bitmaps capability (skip because IN_USE) - source invalidation without dirty-bitmaps capability (bitmaps were dropped, reload them) [1]: to accurately handle this, migration of read-only bitmaps is explicitly forbidden in this patch. New mechanism for not storing bitmaps when migrate with dirty-bitmaps capability is introduced: migration filed in BdrvDirtyBitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'block/dirty-bitmap.c')
-rw-r--r--block/dirty-bitmap.c36
1 files changed, 14 insertions, 22 deletions
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 9b9ebd7..89fd1d7 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;
}
}