| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Joe Thornber | 7117 | 95.45% | 4 | 13.33% |
| Nikos Tsironis | 253 | 3.39% | 8 | 26.67% |
| Heinz Mauelshagen | 55 | 0.74% | 6 | 20.00% |
| Christoph Hellwig | 10 | 0.13% | 4 | 13.33% |
| Krishnasamy, Somasundaram | 6 | 0.08% | 1 | 3.33% |
| Mikulas Patocka | 6 | 0.08% | 1 | 3.33% |
| Michael Christie | 2 | 0.03% | 1 | 3.33% |
| Yangtao Li | 2 | 0.03% | 1 | 3.33% |
| Tushar Sugandhi | 2 | 0.03% | 1 | 3.33% |
| Thomas Gleixner | 1 | 0.01% | 1 | 3.33% |
| Mike Snitzer | 1 | 0.01% | 1 | 3.33% |
| Jens Axboe | 1 | 0.01% | 1 | 3.33% |
| Total | 7456 | 30 |
// 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 "era" #define SUPERBLOCK_LOCATION 0 #define SUPERBLOCK_MAGIC 2126579579 #define SUPERBLOCK_CSUM_XOR 146538381 #define MIN_ERA_VERSION 1 #define MAX_ERA_VERSION 1 #define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION #define MIN_BLOCK_SIZE 8 /* *-------------------------------------------------------------- * Writeset *-------------------------------------------------------------- */ struct writeset_metadata { uint32_t nr_bits; dm_block_t root; }; struct writeset { struct writeset_metadata md; /* * An in core copy of the bits to save constantly doing look ups on * disk. */ unsigned long *bits; }; /* * 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) { vfree(ws->bits); ws->bits = NULL; } static int setup_on_disk_bitset(struct dm_disk_bitset *info, unsigned int nr_bits, dm_block_t *root) { int r; r = dm_bitset_empty(info, root); if (r) return r; return dm_bitset_resize(info, *root, 0, nr_bits, false, root); } static size_t bitset_size(unsigned int nr_bits) { return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG); } /* * Allocates memory for the in core bitset. */ static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks) { ws->bits = vzalloc(bitset_size(nr_blocks)); if (!ws->bits) { DMERR("%s: couldn't allocate in memory bitset", __func__); return -ENOMEM; } return 0; } /* * 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) { int r; memset(ws->bits, 0, bitset_size(nr_blocks)); ws->md.nr_bits = nr_blocks; r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root); if (r) { DMERR("%s: setup_on_disk_bitset failed", __func__); return r; } return 0; } static bool writeset_marked(struct writeset *ws, dm_block_t block) { return test_bit(block, ws->bits); } static int writeset_marked_on_disk(struct dm_disk_bitset *info, struct writeset_metadata *m, dm_block_t block, bool *result) { int r; dm_block_t old = m->root; /* * The bitset was flushed when it was archived, so we know there'll * be no change to the root. */ r = dm_bitset_test_bit(info, m->root, block, &m->root, result); if (r) { DMERR("%s: dm_bitset_test_bit failed", __func__); return r; } BUG_ON(m->root != old); return r; } /* * 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) { int r; if (!test_bit(block, ws->bits)) { r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root); if (r) { /* FIXME: fail mode */ return r; } return 0; } return 1; } /* *-------------------------------------------------------------- * On disk metadata layout *-------------------------------------------------------------- */ #define SPACE_MAP_ROOT_SIZE 128 #define UUID_LEN 16 struct writeset_disk { __le32 nr_bits; __le64 root; } __packed; struct superblock_disk { __le32 csum; __le32 flags; __le64 blocknr; __u8 uuid[UUID_LEN]; __le64 magic; __le32 version; __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; __le32 data_block_size; __le32 metadata_block_size; __le32 nr_blocks; __le32 current_era; struct writeset_disk current_writeset; /* * Only these two fields are valid within the metadata snapshot. */ __le64 writeset_tree_root; __le64 era_array_root; __le64 metadata_snap; } __packed; /* *-------------------------------------------------------------- * Superblock validation *-------------------------------------------------------------- */ static void sb_prepare_for_write(struct dm_block_validator *v, struct dm_block *b, size_t sb_block_size) { struct superblock_disk *disk = dm_block_data(b); disk->blocknr = cpu_to_le64(dm_block_location(b)); disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags, sb_block_size - sizeof(__le32), SUPERBLOCK_CSUM_XOR)); } static int check_metadata_version(struct superblock_disk *disk) { uint32_t metadata_version = le32_to_cpu(disk->version); if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) { DMERR("Era metadata version %u found, but only versions between %u and %u supported.", metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION); return -EINVAL; } return 0; } static int sb_check(struct dm_block_validator *v, struct dm_block *b, size_t sb_block_size) { struct superblock_disk *disk = dm_block_data(b); __le32 csum_le; if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) { DMERR("%s failed: blocknr %llu: wanted %llu", __func__, le64_to_cpu(disk->blocknr), (unsigned long long)dm_block_location(b)); return -ENOTBLK; } if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) { DMERR("%s failed: magic %llu: wanted %llu", __func__, le64_to_cpu(disk->magic), (unsigned long long) SUPERBLOCK_MAGIC); return -EILSEQ; } csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags, sb_block_size - sizeof(__le32), SUPERBLOCK_CSUM_XOR)); if (csum_le != disk->csum) { DMERR("%s failed: csum %u: wanted %u", __func__, le32_to_cpu(csum_le), le32_to_cpu(disk->csum)); return -EILSEQ; } return check_metadata_version(disk); } static struct dm_block_validator sb_validator = { .name = "superblock", .prepare_for_write = sb_prepare_for_write, .check = sb_check }; /* *-------------------------------------------------------------- * Low level metadata handling *-------------------------------------------------------------- */ #define DM_ERA_METADATA_BLOCK_SIZE 4096 #define ERA_MAX_CONCURRENT_LOCKS 5 struct era_metadata { struct block_device *bdev; struct dm_block_manager *bm; struct dm_space_map *sm; struct dm_transaction_manager *tm; dm_block_t block_size; uint32_t nr_blocks; uint32_t current_era; /* * We preallocate 2 writesets. When an era rolls over we * switch between them. This means the allocation is done at * preresume time, rather than on the io path. */ struct writeset writesets[2]; struct writeset *current_writeset; dm_block_t writeset_tree_root; dm_block_t era_array_root; struct dm_disk_bitset bitset_info; struct dm_btree_info writeset_tree_info; struct dm_array_info era_array_info; dm_block_t metadata_snap; /* * A flag that is set whenever a writeset has been archived. */ bool archived_writesets; /* * 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]; }; static int superblock_read_lock(struct era_metadata *md, struct dm_block **sblock) { return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); } static int superblock_lock_zero(struct era_metadata *md, struct dm_block **sblock) { return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); } static int superblock_lock(struct era_metadata *md, struct dm_block **sblock) { return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); } /* FIXME: duplication with cache and thin */ static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result) { int r; unsigned int i; struct dm_block *b; __le64 *data_le, zero = cpu_to_le64(0); unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); /* * We can't use a validator here - it may be all zeroes. */ r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b); if (r) return r; data_le = dm_block_data(b); *result = true; for (i = 0; i < sb_block_size; i++) { if (data_le[i] != zero) { *result = false; break; } } dm_bm_unlock(b); return 0; } /*----------------------------------------------------------------*/ static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk) { disk->nr_bits = cpu_to_le32(core->nr_bits); disk->root = cpu_to_le64(core->root); } static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core) { core->nr_bits = le32_to_cpu(disk->nr_bits); core->root = le64_to_cpu(disk->root); } static void ws_inc(void *context, const void *value, unsigned int count) { struct era_metadata *md = context; struct writeset_disk ws_d; dm_block_t b; unsigned int i; for (i = 0; i < count; i++) { memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d)); b = le64_to_cpu(ws_d.root); dm_tm_inc(md->tm, b); } } static void ws_dec(void *context, const void *value, unsigned int count) { struct era_metadata *md = context; struct writeset_disk ws_d; dm_block_t b; unsigned int i; for (i = 0; i < count; i++) { memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d)); b = le64_to_cpu(ws_d.root); dm_bitset_del(&md->bitset_info, b); } } static int ws_eq(void *context, const void *value1, const void *value2) { return !memcmp(value1, value2, sizeof(struct writeset_disk)); } /*----------------------------------------------------------------*/ static void setup_writeset_tree_info(struct era_metadata *md) { struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type; md->writeset_tree_info.tm = md->tm; md->writeset_tree_info.levels = 1; vt->context = md; vt->size = sizeof(struct writeset_disk); vt->inc = ws_inc; vt->dec = ws_dec; vt->equal = ws_eq; } static void setup_era_array_info(struct era_metadata *md) { struct dm_btree_value_type vt; vt.context = NULL; vt.size = sizeof(__le32); vt.inc = NULL; vt.dec = NULL; vt.equal = NULL; dm_array_info_init(&md->era_array_info, md->tm, &vt); } static void setup_infos(struct era_metadata *md) { dm_disk_bitset_init(md->tm, &md->bitset_info); setup_writeset_tree_info(md); setup_era_array_info(md); } /*----------------------------------------------------------------*/ static int create_fresh_metadata(struct era_metadata *md) { int r; r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION, &md->tm, &md->sm); if (r < 0) { DMERR("dm_tm_create_with_sm failed"); return r; } setup_infos(md); r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root); if (r) { DMERR("couldn't create new writeset tree"); goto bad; } r = dm_array_empty(&md->era_array_info, &md->era_array_root); if (r) { DMERR("couldn't create era array"); goto bad; } return 0; bad: dm_sm_destroy(md->sm); dm_tm_destroy(md->tm); return r; } static int save_sm_root(struct era_metadata *md) { int r; size_t metadata_len; r = dm_sm_root_size(md->sm, &metadata_len); if (r < 0) return r; return dm_sm_copy_root(md->sm, &md->metadata_space_map_root, metadata_len); } static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk) { memcpy(&disk->metadata_space_map_root, &md->metadata_space_map_root, sizeof(md->metadata_space_map_root)); } /* * 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) { disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC); disk->flags = cpu_to_le32(0ul); /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */ memset(disk->uuid, 0, sizeof(disk->uuid)); disk->version = cpu_to_le32(MAX_ERA_VERSION); copy_sm_root(md, disk); disk->data_block_size = cpu_to_le32(md->block_size); disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); disk->nr_blocks = cpu_to_le32(md->nr_blocks); disk->current_era = cpu_to_le32(md->current_era); ws_pack(&md->current_writeset->md, &disk->current_writeset); disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root); disk->era_array_root = cpu_to_le64(md->era_array_root); disk->metadata_snap = cpu_to_le64(md->metadata_snap); } static int write_superblock(struct era_metadata *md) { int r; struct dm_block *sblock; struct superblock_disk *disk; r = save_sm_root(md); if (r) { DMERR("%s: save_sm_root failed", __func__); return r; } r = superblock_lock_zero(md, &sblock); if (r) return r; disk = dm_block_data(sblock); prepare_superblock(md, disk); return dm_tm_commit(md->tm, sblock); } /* * Assumes block_size and the infos are set. */ static int format_metadata(struct era_metadata *md) { int r; r = create_fresh_metadata(md); if (r) return r; r = write_superblock(md); if (r) { dm_sm_destroy(md->sm); dm_tm_destroy(md->tm); return r; } return 0; } static int open_metadata(struct era_metadata *md) { int r; struct dm_block *sblock; struct superblock_disk *disk; r = superblock_read_lock(md, &sblock); if (r) { DMERR("couldn't read_lock superblock"); return r; } disk = dm_block_data(sblock); /* Verify the data block size hasn't changed */ if (le32_to_cpu(disk->data_block_size) != md->block_size) { DMERR("changing the data block size (from %u to %llu) is not supported", le32_to_cpu(disk->data_block_size), md->block_size); r = -EINVAL; goto bad; } r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION, disk->metadata_space_map_root, sizeof(disk->metadata_space_map_root), &md->tm, &md->sm); if (r) { DMERR("dm_tm_open_with_sm failed"); goto bad; } setup_infos(md); md->nr_blocks = le32_to_cpu(disk->nr_blocks); md->current_era = le32_to_cpu(disk->current_era); ws_unpack(&disk->current_writeset, &md->current_writeset->md); md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root); md->era_array_root = le64_to_cpu(disk->era_array_root); md->metadata_snap = le64_to_cpu(disk->metadata_snap); md->archived_writesets = true; dm_bm_unlock(sblock); return 0; bad: dm_bm_unlock(sblock); return r; } static int open_or_format_metadata(struct era_metadata *md, bool may_format) { int r; bool unformatted = false; r = superblock_all_zeroes(md->bm, &unformatted); if (r) return r; if (unformatted) return may_format ? format_metadata(md) : -EPERM; return open_metadata(md); } static int create_persistent_data_objects(struct era_metadata *md, bool may_format) { int r; md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE, ERA_MAX_CONCURRENT_LOCKS); if (IS_ERR(md->bm)) { DMERR("could not create block manager"); return PTR_ERR(md->bm); } r = open_or_format_metadata(md, may_format); if (r) dm_block_manager_destroy(md->bm); return r; } static void destroy_persistent_data_objects(struct era_metadata *md) { dm_sm_destroy(md->sm); dm_tm_destroy(md->tm); dm_block_manager_destroy(md->bm); } /* * 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) { rcu_assign_pointer(md->current_writeset, new_writeset); synchronize_rcu(); } /* *------------------------------------------------------------------------ * 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 { uint32_t era; unsigned int nr_bits, current_bit; struct writeset_metadata writeset; __le32 value; struct dm_disk_bitset info; int (*step)(struct era_metadata *md, struct digest *d); }; 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) { int r; uint64_t key = d->era; r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root, &key, &md->writeset_tree_root); if (r) { DMERR("%s: dm_btree_remove failed", __func__); return r; } d->step = metadata_digest_lookup_writeset; return 0; } #define INSERTS_PER_STEP 100 static int metadata_digest_transcribe_writeset(struct era_metadata *md, struct digest *d) { int r; bool marked; unsigned int b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits); for (b = d->current_bit; b < e; b++) { r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked); if (r) { DMERR("%s: writeset_marked_on_disk failed", __func__); return r; } if (!marked) continue; __dm_bless_for_disk(&d->value); r = dm_array_set_value(&md->era_array_info, md->era_array_root, b, &d->value, &md->era_array_root); if (r) { DMERR("%s: dm_array_set_value failed", __func__); return r; } } if (b == d->nr_bits) d->step = metadata_digest_remove_writeset; else d->current_bit = b; return 0; } static int metadata_digest_lookup_writeset(struct era_metadata *md, struct digest *d) { int r; uint64_t key; struct writeset_disk disk; r = dm_btree_find_lowest_key(&md->writeset_tree_info, md->writeset_tree_root, &key); if (r < 0) return r; d->era = key; r = dm_btree_lookup(&md->writeset_tree_info, md->writeset_tree_root, &key, &disk); if (r) { if (r == -ENODATA) { d->step = NULL; return 0; } DMERR("%s: dm_btree_lookup failed", __func__); return r; } ws_unpack(&disk, &d->writeset); d->value = cpu_to_le32(key); /* * We initialise another bitset info to avoid any caching side effects * with the previous one. */ dm_disk_bitset_init(md->tm, &d->info); d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks); d->current_bit = 0; d->step = metadata_digest_transcribe_writeset; return 0; } static int metadata_digest_start(struct era_metadata *md, struct digest *d) { if (d->step) return 0; memset(d, 0, sizeof(*d)); d->step = metadata_digest_lookup_writeset; return 0; } /* *----------------------------------------------------------------- * 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) { int r; struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL); if (!md) return NULL; md->bdev = bdev; md->block_size = block_size; md->writesets[0].md.root = INVALID_WRITESET_ROOT; md->writesets[1].md.root = INVALID_WRITESET_ROOT; md->current_writeset = &md->writesets[0]; r = create_persistent_data_objects(md, may_format); if (r) { kfree(md); return ERR_PTR(r); } return md; } static void metadata_close(struct era_metadata *md) { writeset_free(&md->writesets[0]); writeset_free(&md->writesets[1]); destroy_persistent_data_objects(md); kfree(md); } static bool valid_nr_blocks(dm_block_t n) { /* * dm_bitset restricts us to 2^32. test_bit & co. restrict us * further to 2^31 - 1 */ return n < (1ull << 31); } static int metadata_resize(struct era_metadata *md, void *arg) { int r; dm_block_t *new_size = arg; __le32 value; if (!valid_nr_blocks(*new_size)) { DMERR("Invalid number of origin blocks %llu", (unsigned long long) *new_size); return -EINVAL; } writeset_free(&md->writesets[0]); writeset_free(&md->writesets[1]); r = writeset_alloc(&md->writesets[0], *new_size); if (r) { DMERR("%s: writeset_alloc failed for writeset 0", __func__); return r; } r = writeset_alloc(&md->writesets[1], *new_size); if (r) { DMERR("%s: writeset_alloc failed for writeset 1", __func__); writeset_free(&md->writesets[0]); return r; } value = cpu_to_le32(0u); __dm_bless_for_disk(&value); r = dm_array_resize(&md->era_array_info, md->era_array_root, md->nr_blocks, *new_size, &value, &md->era_array_root); if (r) { DMERR("%s: dm_array_resize failed", __func__); writeset_free(&md->writesets[0]); writeset_free(&md->writesets[1]); return r; } md->nr_blocks = *new_size; return 0; } static int metadata_era_archive(struct era_metadata *md) { int r; uint64_t keys[1]; struct writeset_disk value; r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, &md->current_writeset->md.root); if (r) { DMERR("%s: dm_bitset_flush failed", __func__); return r; } ws_pack(&md->current_writeset->md, &value); keys[0] = md->current_era; __dm_bless_for_disk(&value); r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root, keys, &value, &md->writeset_tree_root); if (r) { DMERR("%s: couldn't insert writeset into btree", __func__); /* FIXME: fail mode */ return r; } md->current_writeset->md.root = INVALID_WRITESET_ROOT; md->archived_writesets = true; return 0; } static struct writeset *next_writeset(struct era_metadata *md) { return (md->current_writeset == &md->writesets[0]) ? &md->writesets[1] : &md->writesets[0]; } static int metadata_new_era(struct era_metadata *md) { int r; struct writeset *new_writeset = next_writeset(md); r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks); if (r) { DMERR("%s: writeset_init failed", __func__); return r; } swap_writeset(md, new_writeset); md->current_era++; return 0; } static int metadata_era_rollover(struct era_metadata *md) { int r; if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) { r = metadata_era_archive(md); if (r) { DMERR("%s: metadata_archive_era failed", __func__); /* FIXME: fail mode? */ return r; } } r = metadata_new_era(md); if (r) { DMERR("%s: new era failed", __func__); /* FIXME: fail mode */ return r; } return 0; } static bool metadata_current_marked(struct era_metadata *md, dm_block_t block) { bool r; struct writeset *ws; rcu_read_lock(); ws = rcu_dereference(md->current_writeset); r = writeset_marked(ws, block); rcu_read_unlock(); return r; } static int metadata_commit(struct era_metadata *md) { int r; struct dm_block *sblock; if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) { r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root, &md->current_writeset->md.root); if (r) { DMERR("%s: bitset flush failed", __func__); return r; } } r = dm_tm_pre_commit(md->tm); if (r) { DMERR("%s: pre commit failed", __func__); return r; } r = save_sm_root(md); if (r) { DMERR("%s: save_sm_root failed", __func__); return r; } r = superblock_lock(md, &sblock); if (r) { DMERR("%s: superblock lock failed", __func__); return r; } prepare_superblock(md, dm_block_data(sblock)); return dm_tm_commit(md->tm, sblock); } static int metadata_checkpoint(struct era_metadata *md) { /* * For now we just rollover, but later I want to put a check in to * avoid this if the filter is still pretty fresh. */ return metadata_era_rollover(md); } /* * Metadata snapshots allow userland to access era data. */ static int metadata_take_snap(struct era_metadata *md) { int r, inc; struct dm_block *clone; if (md->metadata_snap != SUPERBLOCK_LOCATION) { DMERR("%s: metadata snapshot already exists", __func__); return -EINVAL; } r = metadata_era_rollover(md); if (r) { DMERR("%s: era rollover failed", __func__); return r; } r = metadata_commit(md); if (r) { DMERR("%s: pre commit failed", __func__); return r; } r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION); if (r) { DMERR("%s: couldn't increment superblock", __func__); return r; } r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION, &sb_validator, &clone, &inc); if (r) { DMERR("%s: couldn't shadow superblock", __func__); dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION); return r; } BUG_ON(!inc); r = dm_sm_inc_block(md->sm, md->writeset_tree_root); if (r) { DMERR("%s: couldn't inc writeset tree root", __func__); dm_tm_unlock(md->tm, clone); return r; } r = dm_sm_inc_block(md->sm, md->era_array_root); if (r) { DMERR("%s: couldn't inc era tree root", __func__); dm_sm_dec_block(md->sm, md->writeset_tree_root); dm_tm_unlock(md->tm, clone); return r; } md->metadata_snap = dm_block_location(clone); dm_tm_unlock(md->tm, clone); return 0; } static int metadata_drop_snap(struct era_metadata *md) { int r; dm_block_t location; struct dm_block *clone; struct superblock_disk *disk; if (md->metadata_snap == SUPERBLOCK_LOCATION) { DMERR("%s: no snap to drop", __func__); return -EINVAL; } r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone); if (r) { DMERR("%s: couldn't read lock superblock clone", __func__); return r; } /* * Whatever happens now we'll commit with no record of the metadata * snap. */ md->metadata_snap = SUPERBLOCK_LOCATION; disk = dm_block_data(clone); r = dm_btree_del(&md->writeset_tree_info, le64_to_cpu(disk->writeset_tree_root)); if (r) { DMERR("%s: error deleting writeset tree clone", __func__); dm_tm_unlock(md->tm, clone); return r; } r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root)); if (r) { DMERR("%s: error deleting era array clone", __func__); dm_tm_unlock(md->tm, clone); return r; } location = dm_block_location(clone); dm_tm_unlock(md->tm, clone); return dm_sm_dec_block(md->sm, location); } struct metadata_stats { dm_block_t used; dm_block_t total; dm_block_t snap; uint32_t era; }; static int metadata_get_stats(struct era_metadata *md, void *ptr) { int r; struct metadata_stats *s = ptr; dm_block_t nr_free, nr_total; r = dm_sm_get_nr_free(md->sm, &nr_free); if (r) { DMERR("dm_sm_get_nr_free returned %d", r); return r; } r = dm_sm_get_nr_blocks(md->sm, &nr_total); if (r) { DMERR("dm_pool_get_metadata_dev_size returned %d", r); return r; } s->used = nr_total - nr_free; s->total = nr_total; s->snap = md->metadata_snap; s->era = md->current_era; return 0; } /*----------------------------------------------------------------*/ struct era { struct dm_target *ti; struct dm_dev *metadata_dev; struct dm_dev *origin_dev; dm_block_t nr_blocks; uint32_t sectors_per_block; int sectors_per_block_shift; struct era_metadata *md; struct workqueue_struct *wq; struct work_struct worker; spinlock_t deferred_lock; struct bio_list deferred_bios; spinlock_t rpc_lock; struct list_head rpc_calls; struct digest digest; atomic_t suspended; }; struct rpc { struct list_head list; int (*fn0)(struct era_metadata *md); int (*fn1)(struct era_metadata *md, void *ref); void *arg; int result; struct completion complete; }; /* *--------------------------------------------------------------- * Remapping. *--------------------------------------------------------------- */ static bool block_size_is_power_of_two(struct era *era) { return era->sectors_per_block_shift >= 0; } static dm_block_t get_block(struct era *era, struct bio *bio) { sector_t block_nr = bio->bi_iter.bi_sector; if (!block_size_is_power_of_two(era)) (void) sector_div(block_nr, era->sectors_per_block); else block_nr >>= era->sectors_per_block_shift; return block_nr; } static void remap_to_origin(struct era *era, struct bio *bio) { bio_set_dev(bio, era->origin_dev->bdev); } /* *-------------------------------------------------------------- * Worker thread *-------------------------------------------------------------- */ static void wake_worker(struct era *era) { if (!atomic_read(&era->suspended)) queue_work(era->wq, &era->worker); } static void process_old_eras(struct era *era) { int r; if (!era->digest.step) return; r = era->digest.step(era->md, &era->digest); if (r < 0) { DMERR("%s: digest step failed, stopping digestion", __func__); era->digest.step = NULL; } else if (era->digest.step) wake_worker(era); } static void process_deferred_bios(struct era *era) { int r; struct bio_list deferred_bios, marked_bios; struct bio *bio; struct blk_plug plug; bool commit_needed = false; bool failed = false; struct writeset *ws = era->md->current_writeset; bio_list_init(&deferred_bios); bio_list_init(&marked_bios); spin_lock(&era->deferred_lock); bio_list_merge(&deferred_bios, &era->deferred_bios); bio_list_init(&era->deferred_bios); spin_unlock(&era->deferred_lock); if (bio_list_empty(&deferred_bios)) return; while ((bio = bio_list_pop(&deferred_bios))) { r = writeset_test_and_set(&era->md->bitset_info, ws, get_block(era, bio)); if (r < 0) { /* * This is bad news, we need to rollback. * FIXME: finish. */ failed = true; } else if (r == 0) commit_needed = true; bio_list_add(&marked_bios, bio); } if (commit_needed) { r = metadata_commit(era->md); if (r) failed = true; } if (failed) while ((bio = bio_list_pop(&marked_bios))) bio_io_error(bio); else { blk_start_plug(&plug); while ((bio = bio_list_pop(&marked_bios))) { /* * Only update the in-core writeset if the on-disk one * was updated too. */ if (commit_needed) set_bit(get_block(era, bio), ws->bits); submit_bio_noacct(bio); } blk_finish_plug(&plug); } } static void process_rpc_calls(struct era *era) { int r; bool need_commit = false; struct list_head calls; struct rpc *rpc, *tmp; INIT_LIST_HEAD(&calls); spin_lock(&era->rpc_lock); list_splice_init(&era->rpc_calls, &calls); spin_unlock(&era->rpc_lock); list_for_each_entry_safe(rpc, tmp, &calls, list) { rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg); need_commit = true; } if (need_commit) { r = metadata_commit(era->md); if (r) list_for_each_entry_safe(rpc, tmp, &calls, list) rpc->result = r; } list_for_each_entry_safe(rpc, tmp, &calls, list) complete(&rpc->complete); } static void kick_off_digest(struct era *era) { if (era->md->archived_writesets) { era->md->archived_writesets = false; metadata_digest_start(era->md, &era->digest); } } static void do_work(struct work_struct *ws) { struct era *era = container_of(ws, struct era, worker); kick_off_digest(era); process_old_eras(era); process_deferred_bios(era); process_rpc_calls(era); } static void defer_bio(struct era *era, struct bio *bio) { spin_lock(&era->deferred_lock); bio_list_add(&era->deferred_bios, bio); spin_unlock(&era->deferred_lock); wake_worker(era); } /* * Make an rpc call to the worker to change the metadata. */ static int perform_rpc(struct era *era, struct rpc *rpc) { rpc->result = 0; init_completion(&rpc->complete); spin_lock(&era->rpc_lock); list_add(&rpc->list, &era->rpc_calls); spin_unlock(&era->rpc_lock); wake_worker(era); wait_for_completion(&rpc->complete); return rpc->result; } static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md)) { struct rpc rpc; rpc.fn0 = fn; rpc.fn1 = NULL; return perform_rpc(era, &rpc); } static int in_worker1(struct era *era, int (*fn)(struct era_metadata *md, void *ref), void *arg) { struct rpc rpc; rpc.fn0 = NULL; rpc.fn1 = fn; rpc.arg = arg; return perform_rpc(era, &rpc); } static void start_worker(struct era *era) { atomic_set(&era->suspended, 0); } static void stop_worker(struct era *era) { atomic_set(&era->suspended, 1); drain_workqueue(era->wq); } /* *-------------------------------------------------------------- * Target methods *-------------------------------------------------------------- */ static void era_destroy(struct era *era) { if (era->md) metadata_close(era->md); if (era->wq) destroy_workqueue(era->wq); if (era->origin_dev) dm_put_device(era->ti, era->origin_dev); if (era->metadata_dev) dm_put_device(era->ti, era->metadata_dev); kfree(era); } static dm_block_t calc_nr_blocks(struct era *era) { return dm_sector_div_up(era->ti->len, era->sectors_per_block); } static bool valid_block_size(dm_block_t block_size) { bool greater_than_zero = block_size > 0; bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0; return greater_than_zero && multiple_of_min_block_size; } /* * <metadata dev> <data dev> <data block size (sectors)> */ static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv) { int r; char dummy; struct era *era; struct era_metadata *md; if (argc != 3) { ti->error = "Invalid argument count"; return -EINVAL; } era = kzalloc(sizeof(*era), GFP_KERNEL); if (!era) { ti->error = "Error allocating era structure"; return -ENOMEM; } era->ti = ti; r = dm_get_device(ti, argv[0], BLK_OPEN_READ | BLK_OPEN_WRITE, &era->metadata_dev); if (r) { ti->error = "Error opening metadata device"; era_destroy(era); return -EINVAL; } r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE, &era->origin_dev); if (r) { ti->error = "Error opening data device"; era_destroy(era); return -EINVAL; } r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy); if (r != 1) { ti->error = "Error parsing block size"; era_destroy(era); return -EINVAL; } r = dm_set_target_max_io_len(ti, era->sectors_per_block); if (r) { ti->error = "could not set max io len"; era_destroy(era); return -EINVAL; } if (!valid_block_size(era->sectors_per_block)) { ti->error = "Invalid block size"; era_destroy(era); return -EINVAL; } if (era->sectors_per_block & (era->sectors_per_block - 1)) era->sectors_per_block_shift = -1; else era->sectors_per_block_shift = __ffs(era->sectors_per_block); md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true); if (IS_ERR(md)) { ti->error = "Error reading metadata"; era_destroy(era); return PTR_ERR(md); } era->md = md; era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); if (!era->wq) { ti->error = "could not create workqueue for metadata object"; era_destroy(era); return -ENOMEM; } INIT_WORK(&era->worker, do_work); spin_lock_init(&era->deferred_lock); bio_list_init(&era->deferred_bios); spin_lock_init(&era->rpc_lock); INIT_LIST_HEAD(&era->rpc_calls); ti->private = era; ti->num_flush_bios = 1; ti->flush_supported = true; ti->num_discard_bios = 1; return 0; } static void era_dtr(struct dm_target *ti) { era_destroy(ti->private); } static int era_map(struct dm_target *ti, struct bio *bio) { struct era *era = ti->private; dm_block_t block = get_block(era, bio); /* * All bios get remapped to the origin device. We do this now, but * it may not get issued until later. Depending on whether the * block is marked in this era. */ remap_to_origin(era, bio); /* * REQ_PREFLUSH bios carry no data, so we're not interested in them. */ if (!(bio->bi_opf & REQ_PREFLUSH) && (bio_data_dir(bio) == WRITE) && !metadata_current_marked(era->md, block)) { defer_bio(era, bio); return DM_MAPIO_SUBMITTED; } return DM_MAPIO_REMAPPED; } static void era_postsuspend(struct dm_target *ti) { int r; struct era *era = ti->private; r = in_worker0(era, metadata_era_archive); if (r) { DMERR("%s: couldn't archive current era", __func__); /* FIXME: fail mode */ } stop_worker(era); r = metadata_commit(era->md); if (r) { DMERR("%s: metadata_commit failed", __func__); /* FIXME: fail mode */ } } static int era_preresume(struct dm_target *ti) { int r; struct era *era = ti->private; dm_block_t new_size = calc_nr_blocks(era); if (era->nr_blocks != new_size) { r = metadata_resize(era->md, &new_size); if (r) { DMERR("%s: metadata_resize failed", __func__); return r; } r = metadata_commit(era->md); if (r) { DMERR("%s: metadata_commit failed", __func__); return r; } era->nr_blocks = new_size; } start_worker(era); r = in_worker0(era, metadata_era_rollover); if (r) { DMERR("%s: metadata_era_rollover failed", __func__); return r; } return 0; } /* * 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) { int r; struct era *era = ti->private; ssize_t sz = 0; struct metadata_stats stats; char buf[BDEVNAME_SIZE]; switch (type) { case STATUSTYPE_INFO: r = in_worker1(era, metadata_get_stats, &stats); if (r) goto err; DMEMIT("%u %llu/%llu %u", (unsigned int) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT), (unsigned long long) stats.used, (unsigned long long) stats.total, (unsigned int) stats.era); if (stats.snap != SUPERBLOCK_LOCATION) DMEMIT(" %llu", stats.snap); else DMEMIT(" -"); break; case STATUSTYPE_TABLE: format_dev_t(buf, era->metadata_dev->bdev->bd_dev); DMEMIT("%s ", buf); format_dev_t(buf, era->origin_dev->bdev->bd_dev); DMEMIT("%s %u", buf, era->sectors_per_block); break; case STATUSTYPE_IMA: *result = '\0'; break; } return; err: DMEMIT("Error"); } static int era_message(struct dm_target *ti, unsigned int argc, char **argv, char *result, unsigned int maxlen) { struct era *era = ti->private; if (argc != 1) { DMERR("incorrect number of message arguments"); return -EINVAL; } if (!strcasecmp(argv[0], "checkpoint")) return in_worker0(era, metadata_checkpoint); if (!strcasecmp(argv[0], "take_metadata_snap")) return in_worker0(era, metadata_take_snap); if (!strcasecmp(argv[0], "drop_metadata_snap")) return in_worker0(era, metadata_drop_snap); DMERR("unsupported message '%s'", argv[0]); return -EINVAL; } static sector_t get_dev_size(struct dm_dev *dev) { return bdev_nr_sectors(dev->bdev); } static int era_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct era *era = ti->private; return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data); } static void era_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct era *era = ti->private; uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; /* * If the system-determined stacked limits are compatible with the * era device's blocksize (io_opt is a factor) do not override them. */ if (io_opt_sectors < era->sectors_per_block || do_div(io_opt_sectors, era->sectors_per_block)) { blk_limits_io_min(limits, 0); blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT); } } /*----------------------------------------------------------------*/ static struct target_type era_target = { .name = "era", .version = {1, 0, 0}, .module = THIS_MODULE, .ctr = era_ctr, .dtr = era_dtr, .map = era_map, .postsuspend = era_postsuspend, .preresume = era_preresume, .status = era_status, .message = era_message, .iterate_devices = era_iterate_devices, .io_hints = era_io_hints }; module_dm(era); MODULE_DESCRIPTION(DM_NAME " era target"); MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); MODULE_LICENSE("GPL");
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