diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/block/block_int.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/include/block/block_int.h b/include/block/block_int.h index 12e5750fe8..437d746733 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -34,6 +34,7 @@ #include "qemu/hbitmap.h" #include "block/snapshot.h" #include "qemu/throttle.h" +#include "qemu/rcu.h" #define BLOCK_FLAG_LAZY_REFCOUNTS 8 @@ -839,6 +840,24 @@ struct BdrvChild { QLIST_ENTRY(BdrvChild) next_parent; }; +/* + * Allows bdrv_co_block_status() to cache one data region for a + * protocol node. + * + * @valid: Whether the cache is valid (should be accessed with atomic + * functions so this can be reset by RCU readers) + * @data_start: Offset where we know (or strongly assume) is data + * @data_end: Offset where the data region ends (which is not necessarily + * the start of a zeroed region) + */ +typedef struct BdrvBlockStatusCache { + struct rcu_head rcu; + + bool valid; + int64_t data_start; + int64_t data_end; +} BdrvBlockStatusCache; + struct BlockDriverState { /* Protected by big QEMU lock or read-only after opening. No special * locking needed during I/O... @@ -1004,6 +1023,11 @@ struct BlockDriverState { /* BdrvChild links to this node may never be frozen */ bool never_freeze; + + /* Lock for block-status cache RCU writers */ + CoMutex bsc_modify_lock; + /* Always non-NULL, but must only be dereferenced under an RCU read guard */ + BdrvBlockStatusCache *block_status_cache; }; struct BlockBackendRootState { @@ -1429,4 +1453,30 @@ static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs) */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); +/** + * Check whether the given offset is in the cached block-status data + * region. + * + * If it is, and @pnum is not NULL, *pnum is set to + * `bsc.data_end - offset`, i.e. how many bytes, starting from + * @offset, are data (according to the cache). + * Otherwise, *pnum is not touched. + */ +bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum); + +/** + * If [offset, offset + bytes) overlaps with the currently cached + * block-status region, invalidate the cache. + * + * (To be used by I/O paths that cause data regions to be zero or + * holes.) + */ +void bdrv_bsc_invalidate_range(BlockDriverState *bs, + int64_t offset, int64_t bytes); + +/** + * Mark the range [offset, offset + bytes) as a data region. + */ +void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes); + #endif /* BLOCK_INT_H */ |