drivers/md/dm-cache-metadata.c

Source file repositories/reference/linux-study-clean/drivers/md/dm-cache-metadata.c

File Facts

System
Linux kernel
Corpus path
drivers/md/dm-cache-metadata.c
Extension
.c
Size
43681 bytes
Lines
1828
Domain
Driver Families
Bucket
drivers/md
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct cache_disk_superblock {
	__le32 csum;
	__le32 flags;
	__le64 blocknr;

	__u8 uuid[16];
	__le64 magic;
	__le32 version;

	__u8 policy_name[CACHE_POLICY_NAME_SIZE];
	__le32 policy_hint_size;

	__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
	__le64 mapping_root;
	__le64 hint_root;

	__le64 discard_root;
	__le64 discard_block_size;
	__le64 discard_nr_blocks;

	__le32 data_block_size;
	__le32 metadata_block_size;
	__le32 cache_blocks;

	__le32 compat_flags;
	__le32 compat_ro_flags;
	__le32 incompat_flags;

	__le32 read_hits;
	__le32 read_misses;
	__le32 write_hits;
	__le32 write_misses;

	__le32 policy_version[CACHE_POLICY_VERSION_SIZE];

	/*
	 * Metadata format 2 fields.
	 */
	__le64 dirty_root;
} __packed;

struct dm_cache_metadata {
	refcount_t ref_count;
	struct list_head list;

	unsigned int version;
	struct block_device *bdev;
	struct dm_block_manager *bm;
	struct dm_space_map *metadata_sm;
	struct dm_transaction_manager *tm;

	struct dm_array_info info;
	struct dm_array_info hint_info;
	struct dm_disk_bitset discard_info;

	struct rw_semaphore root_lock;
	unsigned long flags;
	dm_block_t root;
	dm_block_t hint_root;
	dm_block_t discard_root;

	sector_t discard_block_size;
	dm_dblock_t discard_nr_blocks;

	sector_t data_block_size;
	dm_cblock_t cache_blocks;
	bool changed:1;
	bool clean_when_opened:1;

	char policy_name[CACHE_POLICY_NAME_SIZE];
	unsigned int policy_version[CACHE_POLICY_VERSION_SIZE];
	size_t policy_hint_size;
	struct dm_cache_statistics stats;

	/*
	 * Reading the space map root can fail, so we read it into this
	 * buffer before the superblock is locked and updated.
	 */
	__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];

	/*
	 * Set if a transaction has to be aborted but the attempt to roll
	 * back to the previous (good) transaction failed.  The only
	 * metadata operation permissible in this state is the closing of
	 * the device.
	 */
	bool fail_io:1;

	/*
	 * Metadata format 2 fields.

Annotation

Implementation Notes