// SPDX-License-Identifier: GPL-2.0-only #include "dm.h" #include "persistent-data/dm-transaction-manager.h" #include "persistent-data/dm-bitset.h" #include "persistent-data/dm-space-map.h" #include <linux/dm-io.h> #include <linux/dm-kcopyd.h> #include <linux/init.h> #include <linux/mempool.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> #define DM_MSG_PREFIX … #define SUPERBLOCK_LOCATION … #define SUPERBLOCK_MAGIC … #define SUPERBLOCK_CSUM_XOR … #define MIN_ERA_VERSION … #define MAX_ERA_VERSION … #define INVALID_WRITESET_ROOT … #define MIN_BLOCK_SIZE … /* *-------------------------------------------------------------- * Writeset *-------------------------------------------------------------- */ struct writeset_metadata { … }; struct writeset { … }; /* * This does not free off the on disk bitset as this will normally be done * after digesting into the era array. */ static void writeset_free(struct writeset *ws) { … } static int setup_on_disk_bitset(struct dm_disk_bitset *info, unsigned int nr_bits, dm_block_t *root) { … } static size_t bitset_size(unsigned int nr_bits) { … } /* * Allocates memory for the in core bitset. */ static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks) { … } /* * Wipes the in-core bitset, and creates a new on disk bitset. */ static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws, dm_block_t nr_blocks) { … } static bool writeset_marked(struct writeset *ws, dm_block_t block) { … } static int writeset_marked_on_disk(struct dm_disk_bitset *info, struct writeset_metadata *m, dm_block_t block, bool *result) { … } /* * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was. */ static int writeset_test_and_set(struct dm_disk_bitset *info, struct writeset *ws, uint32_t block) { … } /* *-------------------------------------------------------------- * On disk metadata layout *-------------------------------------------------------------- */ #define SPACE_MAP_ROOT_SIZE … #define UUID_LEN … struct writeset_disk { … } __packed; struct superblock_disk { … } __packed; /* *-------------------------------------------------------------- * Superblock validation *-------------------------------------------------------------- */ static void sb_prepare_for_write(const struct dm_block_validator *v, struct dm_block *b, size_t sb_block_size) { … } static int check_metadata_version(struct superblock_disk *disk) { … } static int sb_check(const struct dm_block_validator *v, struct dm_block *b, size_t sb_block_size) { … } static const struct dm_block_validator sb_validator = …; /* *-------------------------------------------------------------- * Low level metadata handling *-------------------------------------------------------------- */ #define DM_ERA_METADATA_BLOCK_SIZE … #define ERA_MAX_CONCURRENT_LOCKS … struct era_metadata { … }; static int superblock_read_lock(struct era_metadata *md, struct dm_block **sblock) { … } static int superblock_lock_zero(struct era_metadata *md, struct dm_block **sblock) { … } static int superblock_lock(struct era_metadata *md, struct dm_block **sblock) { … } /* FIXME: duplication with cache and thin */ static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result) { … } /*----------------------------------------------------------------*/ static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk) { … } static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core) { … } static void ws_inc(void *context, const void *value, unsigned int count) { … } static void ws_dec(void *context, const void *value, unsigned int count) { … } static int ws_eq(void *context, const void *value1, const void *value2) { … } /*----------------------------------------------------------------*/ static void setup_writeset_tree_info(struct era_metadata *md) { … } static void setup_era_array_info(struct era_metadata *md) { … } static void setup_infos(struct era_metadata *md) { … } /*----------------------------------------------------------------*/ static int create_fresh_metadata(struct era_metadata *md) { … } static int save_sm_root(struct era_metadata *md) { … } static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk) { … } /* * Writes a superblock, including the static fields that don't get updated * with every commit (possible optimisation here). 'md' should be fully * constructed when this is called. */ static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk) { … } static int write_superblock(struct era_metadata *md) { … } /* * Assumes block_size and the infos are set. */ static int format_metadata(struct era_metadata *md) { … } static int open_metadata(struct era_metadata *md) { … } static int open_or_format_metadata(struct era_metadata *md, bool may_format) { … } static int create_persistent_data_objects(struct era_metadata *md, bool may_format) { … } static void destroy_persistent_data_objects(struct era_metadata *md) { … } /* * This waits until all era_map threads have picked up the new filter. */ static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset) { … } /* *------------------------------------------------------------------------ * Writesets get 'digested' into the main era array. * * We're using a coroutine here so the worker thread can do the digestion, * thus avoiding synchronisation of the metadata. Digesting a whole * writeset in one go would cause too much latency. *------------------------------------------------------------------------ */ struct digest { … }; static int metadata_digest_lookup_writeset(struct era_metadata *md, struct digest *d); static int metadata_digest_remove_writeset(struct era_metadata *md, struct digest *d) { … } #define INSERTS_PER_STEP … static int metadata_digest_transcribe_writeset(struct era_metadata *md, struct digest *d) { … } static int metadata_digest_lookup_writeset(struct era_metadata *md, struct digest *d) { … } static int metadata_digest_start(struct era_metadata *md, struct digest *d) { … } /* *----------------------------------------------------------------- * High level metadata interface. Target methods should use these, * and not the lower level ones. *----------------------------------------------------------------- */ static struct era_metadata *metadata_open(struct block_device *bdev, sector_t block_size, bool may_format) { … } static void metadata_close(struct era_metadata *md) { … } static bool valid_nr_blocks(dm_block_t n) { … } static int metadata_resize(struct era_metadata *md, void *arg) { … } static int metadata_era_archive(struct era_metadata *md) { … } static struct writeset *next_writeset(struct era_metadata *md) { … } static int metadata_new_era(struct era_metadata *md) { … } static int metadata_era_rollover(struct era_metadata *md) { … } static bool metadata_current_marked(struct era_metadata *md, dm_block_t block) { … } static int metadata_commit(struct era_metadata *md) { … } static int metadata_checkpoint(struct era_metadata *md) { … } /* * Metadata snapshots allow userland to access era data. */ static int metadata_take_snap(struct era_metadata *md) { … } static int metadata_drop_snap(struct era_metadata *md) { … } struct metadata_stats { … }; static int metadata_get_stats(struct era_metadata *md, void *ptr) { … } /*----------------------------------------------------------------*/ struct era { … }; struct rpc { … }; /* *--------------------------------------------------------------- * Remapping. *--------------------------------------------------------------- */ static bool block_size_is_power_of_two(struct era *era) { … } static dm_block_t get_block(struct era *era, struct bio *bio) { … } static void remap_to_origin(struct era *era, struct bio *bio) { … } /* *-------------------------------------------------------------- * Worker thread *-------------------------------------------------------------- */ static void wake_worker(struct era *era) { … } static void process_old_eras(struct era *era) { … } static void process_deferred_bios(struct era *era) { … } static void process_rpc_calls(struct era *era) { … } static void kick_off_digest(struct era *era) { … } static void do_work(struct work_struct *ws) { … } static void defer_bio(struct era *era, struct bio *bio) { … } /* * Make an rpc call to the worker to change the metadata. */ static int perform_rpc(struct era *era, struct rpc *rpc) { … } static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md)) { … } static int in_worker1(struct era *era, int (*fn)(struct era_metadata *md, void *ref), void *arg) { … } static void start_worker(struct era *era) { … } static void stop_worker(struct era *era) { … } /* *-------------------------------------------------------------- * Target methods *-------------------------------------------------------------- */ static void era_destroy(struct era *era) { … } static dm_block_t calc_nr_blocks(struct era *era) { … } static bool valid_block_size(dm_block_t block_size) { … } /* * <metadata dev> <data dev> <data block size (sectors)> */ static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv) { … } static void era_dtr(struct dm_target *ti) { … } static int era_map(struct dm_target *ti, struct bio *bio) { … } static void era_postsuspend(struct dm_target *ti) { … } static int era_preresume(struct dm_target *ti) { … } /* * Status format: * * <metadata block size> <#used metadata blocks>/<#total metadata blocks> * <current era> <held metadata root | '-'> */ static void era_status(struct dm_target *ti, status_type_t type, unsigned int status_flags, char *result, unsigned int maxlen) { … } static int era_message(struct dm_target *ti, unsigned int argc, char **argv, char *result, unsigned int maxlen) { … } static sector_t get_dev_size(struct dm_dev *dev) { … } static int era_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { … } static void era_io_hints(struct dm_target *ti, struct queue_limits *limits) { … } /*----------------------------------------------------------------*/ static struct target_type era_target = …; module_dm(era); MODULE_DESCRIPTION(…) …; MODULE_AUTHOR(…) …; MODULE_LICENSE(…) …;
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