diff options
| -rw-r--r-- | block.c | 104 | ||||
| -rw-r--r-- | blockdev.c | 7 | ||||
| -rw-r--r-- | include/block/block.h | 10 | ||||
| -rw-r--r-- | qapi/block-core.json | 1 |
4 files changed, 121 insertions, 1 deletions
@@ -52,8 +52,17 @@ #include <windows.h> #endif +/** + * A BdrvDirtyBitmap can be in three possible states: + * (1) successor is NULL and disabled is false: full r/w mode + * (2) successor is NULL and disabled is true: read only mode ("disabled") + * (3) successor is set: frozen mode. + * A frozen bitmap cannot be renamed, deleted, anonymized, cleared, set, + * or enabled. A frozen bitmap can only abdicate() or reclaim(). + */ struct BdrvDirtyBitmap { HBitmap *bitmap; + BdrvDirtyBitmap *successor; char *name; bool disabled; QLIST_ENTRY(BdrvDirtyBitmap) list; @@ -5518,6 +5527,7 @@ BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name) void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) { + assert(!bdrv_dirty_bitmap_frozen(bitmap)); g_free(bitmap->name); bitmap->name = NULL; } @@ -5553,9 +5563,98 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, return bitmap; } +bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap) +{ + return bitmap->successor; +} + bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap) { - return !bitmap->disabled; + return !(bitmap->disabled || bitmap->successor); +} + +/** + * Create a successor bitmap destined to replace this bitmap after an operation. + * Requires that the bitmap is not frozen and has no successor. + */ +int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, Error **errp) +{ + uint64_t granularity; + BdrvDirtyBitmap *child; + + if (bdrv_dirty_bitmap_frozen(bitmap)) { + error_setg(errp, "Cannot create a successor for a bitmap that is " + "currently frozen"); + return -1; + } + assert(!bitmap->successor); + + /* Create an anonymous successor */ + granularity = bdrv_dirty_bitmap_granularity(bitmap); + child = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); + if (!child) { + return -1; + } + + /* Successor will be on or off based on our current state. */ + child->disabled = bitmap->disabled; + + /* Install the successor and freeze the parent */ + bitmap->successor = child; + return 0; +} + +/** + * For a bitmap with a successor, yield our name to the successor, + * delete the old bitmap, and return a handle to the new bitmap. + */ +BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, + Error **errp) +{ + char *name; + BdrvDirtyBitmap *successor = bitmap->successor; + + if (successor == NULL) { + error_setg(errp, "Cannot relinquish control if " + "there's no successor present"); + return NULL; + } + + name = bitmap->name; + bitmap->name = NULL; + successor->name = name; + bitmap->successor = NULL; + bdrv_release_dirty_bitmap(bs, bitmap); + + return successor; +} + +/** + * In cases of failure where we can no longer safely delete the parent, + * we may wish to re-join the parent and child/successor. + * The merged parent will be un-frozen, but not explicitly re-enabled. + */ +BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs, + BdrvDirtyBitmap *parent, + Error **errp) +{ + BdrvDirtyBitmap *successor = parent->successor; + + if (!successor) { + error_setg(errp, "Cannot reclaim a successor when none is present"); + return NULL; + } + + if (!hbitmap_merge(parent->bitmap, successor->bitmap)) { + error_setg(errp, "Merging of parent and successor bitmap failed"); + return NULL; + } + bdrv_release_dirty_bitmap(bs, successor); + parent->successor = NULL; + + return parent; } void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) @@ -5563,6 +5662,7 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) BdrvDirtyBitmap *bm, *next; QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { if (bm == bitmap) { + assert(!bdrv_dirty_bitmap_frozen(bm)); QLIST_REMOVE(bitmap, list); hbitmap_free(bitmap->bitmap); g_free(bitmap->name); @@ -5574,11 +5674,13 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap) { + assert(!bdrv_dirty_bitmap_frozen(bitmap)); bitmap->disabled = true; } void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap) { + assert(!bdrv_dirty_bitmap_frozen(bitmap)); bitmap->disabled = false; } diff --git a/blockdev.c b/blockdev.c index 5dde1e86da..e8b712e7e2 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2065,9 +2065,16 @@ void qmp_block_dirty_bitmap_remove(const char *node, const char *name, return; } + if (bdrv_dirty_bitmap_frozen(bitmap)) { + error_setg(errp, + "Bitmap '%s' is currently frozen and cannot be removed", + name); + goto out; + } bdrv_dirty_bitmap_make_anon(bs, bitmap); bdrv_release_dirty_bitmap(bs, bitmap); + out: aio_context_release(aio_context); } diff --git a/include/block/block.h b/include/block/block.h index 5d131f0372..1635c227f3 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -454,6 +454,15 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, uint32_t granularity, const char *name, Error **errp); +int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, + Error **errp); +BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, + Error **errp); +BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs, + BdrvDirtyBitmap *bitmap, + Error **errp); BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name); void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap); @@ -464,6 +473,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs); uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs); uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap); bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap); +bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap); int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector); void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t cur_sector, int nr_sectors); diff --git a/qapi/block-core.json b/qapi/block-core.json index 6237f9d437..f3b92d80c9 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1008,6 +1008,7 @@ # Returns: nothing on success # If @node is not a valid block device or node, DeviceNotFound # If @name is not found, GenericError with an explanation +# if @name is frozen by an operation, GenericError # # Since 2.4 ## |