drivers/md/dm-thin-metadata.c

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

File Facts

System
Linux kernel
Corpus path
drivers/md/dm-thin-metadata.c
Extension
.c
Size
49450 bytes
Lines
2161
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 thin_disk_superblock {
	__le32 csum;	/* Checksum of superblock except for this field. */
	__le32 flags;
	__le64 blocknr;	/* This block number, dm_block_t. */

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

	__le64 trans_id;

	/*
	 * Root held by userspace transactions.
	 */
	__le64 held_root;

	__u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
	__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];

	/*
	 * 2-level btree mapping (dev_id, (dev block, time)) -> data block
	 */
	__le64 data_mapping_root;

	/*
	 * Device detail root mapping dev_id -> device_details
	 */
	__le64 device_details_root;

	__le32 data_block_size;		/* In 512-byte sectors. */

	__le32 metadata_block_size;	/* In 512-byte sectors. */
	__le64 metadata_nr_blocks;

	__le32 compat_flags;
	__le32 compat_ro_flags;
	__le32 incompat_flags;
} __packed;

struct disk_device_details {
	__le64 mapped_blocks;
	__le64 transaction_id;		/* When created. */
	__le32 creation_time;
	__le32 snapshotted_time;
} __packed;

struct dm_pool_metadata {
	struct hlist_node hash;

	struct block_device *bdev;
	struct dm_block_manager *bm;
	struct dm_space_map *metadata_sm;
	struct dm_space_map *data_sm;
	struct dm_transaction_manager *tm;
	struct dm_transaction_manager *nb_tm;

	/*
	 * Two-level btree.
	 * First level holds thin_dev_t.
	 * Second level holds mappings.
	 */
	struct dm_btree_info info;

	/*
	 * Non-blocking version of the above.
	 */
	struct dm_btree_info nb_info;

	/*
	 * Just the top level for deleting whole devices.
	 */
	struct dm_btree_info tl_info;

	/*
	 * Just the bottom level for creating new devices.
	 */
	struct dm_btree_info bl_info;

	/*
	 * Describes the device details btree.
	 */
	struct dm_btree_info details_info;

	struct rw_semaphore root_lock;
	uint32_t time;
	dm_block_t root;
	dm_block_t details_root;
	struct list_head thin_devices;
	uint64_t trans_id;

Annotation

Implementation Notes