diff options
Diffstat (limited to 'drivers/md/dm-thin-metadata.c')
| -rw-r--r-- | drivers/md/dm-thin-metadata.c | 1391 |
1 files changed, 1391 insertions, 0 deletions
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c new file mode 100644 index 000000000000..59c4f0446ffa --- /dev/null +++ b/drivers/md/dm-thin-metadata.c @@ -0,0 +1,1391 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-thin-metadata.h" +#include "persistent-data/dm-btree.h" +#include "persistent-data/dm-space-map.h" +#include "persistent-data/dm-space-map-disk.h" +#include "persistent-data/dm-transaction-manager.h" + +#include <linux/list.h> +#include <linux/device-mapper.h> +#include <linux/workqueue.h> + +/*-------------------------------------------------------------------------- + * As far as the metadata goes, there is: + * + * - A superblock in block zero, taking up fewer than 512 bytes for + * atomic writes. + * + * - A space map managing the metadata blocks. + * + * - A space map managing the data blocks. + * + * - A btree mapping our internal thin dev ids onto struct disk_device_details. + * + * - A hierarchical btree, with 2 levels which effectively maps (thin + * dev id, virtual block) -> block_time. Block time is a 64-bit + * field holding the time in the low 24 bits, and block in the top 48 + * bits. + * + * BTrees consist solely of btree_nodes, that fill a block. Some are + * internal nodes, as such their values are a __le64 pointing to other + * nodes. Leaf nodes can store data of any reasonable size (ie. much + * smaller than the block size). The nodes consist of the header, + * followed by an array of keys, followed by an array of values. We have + * to binary search on the keys so they're all held together to help the + * cpu cache. + * + * Space maps have 2 btrees: + * + * - One maps a uint64_t onto a struct index_entry. Which points to a + * bitmap block, and has some details about how many free entries there + * are etc. + * + * - The bitmap blocks have a header (for the checksum). Then the rest + * of the block is pairs of bits. With the meaning being: + * + * 0 - ref count is 0 + * 1 - ref count is 1 + * 2 - ref count is 2 + * 3 - ref count is higher than 2 + * + * - If the count is higher than 2 then the ref count is entered in a + * second btree that directly maps the block_address to a uint32_t ref + * count. + * + * The space map metadata variant doesn't have a bitmaps btree. Instead + * it has one single blocks worth of index_entries. This avoids + * recursive issues with the bitmap btree needing to allocate space in + * order to insert. With a small data block size such as 64k the + * metadata support data devices that are hundreds of terrabytes. + * + * The space maps allocate space linearly from front to back. Space that + * is freed in a transaction is never recycled within that transaction. + * To try and avoid fragmenting _free_ space the allocator always goes + * back and fills in gaps. + * + * All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks + * from the block manager. + *--------------------------------------------------------------------------*/ + +#define DM_MSG_PREFIX "thin metadata" + +#define THIN_SUPERBLOCK_MAGIC 27022010 +#define THIN_SUPERBLOCK_LOCATION 0 +#define THIN_VERSION 1 +#define THIN_METADATA_CACHE_SIZE 64 +#define SECTOR_TO_BLOCK_SHIFT 3 + +/* This should be plenty */ +#define SPACE_MAP_ROOT_SIZE 128 + +/* + * Little endian on-disk superblock and device details. + */ +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; + int need_commit; + dm_block_t root; + dm_block_t details_root; + struct list_head thin_devices; + uint64_t trans_id; + unsigned long flags; + sector_t data_block_size; +}; + +struct dm_thin_device { + struct list_head list; + struct dm_pool_metadata *pmd; + dm_thin_id id; + + int open_count; + int changed; + uint64_t mapped_blocks; + uint64_t transaction_id; + uint32_t creation_time; + uint32_t snapshotted_time; +}; + +/*---------------------------------------------------------------- + * superblock validator + *--------------------------------------------------------------*/ + +#define SUPERBLOCK_CSUM_XOR 160774 + +static void sb_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct thin_disk_superblock *disk_super = dm_block_data(b); + + disk_super->blocknr = cpu_to_le64(dm_block_location(b)); + disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); +} + +static int sb_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct thin_disk_superblock *disk_super = dm_block_data(b); + __le32 csum_le; + + if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { + DMERR("sb_check failed: blocknr %llu: " + "wanted %llu", le64_to_cpu(disk_super->blocknr), + (unsigned long long)dm_block_location(b)); + return -ENOTBLK; + } + + if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) { + DMERR("sb_check failed: magic %llu: " + "wanted %llu", le64_to_cpu(disk_super->magic), + (unsigned long long)THIN_SUPERBLOCK_MAGIC); + return -EILSEQ; + } + + csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); + if (csum_le != disk_super->csum) { + DMERR("sb_check failed: csum %u: wanted %u", + le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator sb_validator = { + .name = "superblock", + .prepare_for_write = sb_prepare_for_write, + .check = sb_check +}; + +/*---------------------------------------------------------------- + * Methods for the btree value types + *--------------------------------------------------------------*/ + +static uint64_t pack_block_time(dm_block_t b, uint32_t t) +{ + return (b << 24) | t; +} + +static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t) +{ + *b = v >> 24; + *t = v & ((1 << 24) - 1); +} + +static void data_block_inc(void *context, void *value_le) +{ + struct dm_space_map *sm = context; + __le64 v_le; + uint64_t b; + uint32_t t; + + memcpy(&v_le, value_le, sizeof(v_le)); + unpack_block_time(le64_to_cpu(v_le), &b, &t); + dm_sm_inc_block(sm, b); +} + +static void data_block_dec(void *context, void *value_le) +{ + struct dm_space_map *sm = context; + __le64 v_le; + uint64_t b; + uint32_t t; + + memcpy(&v_le, value_le, sizeof(v_le)); + unpack_block_time(le64_to_cpu(v_le), &b, &t); + dm_sm_dec_block(sm, b); +} + +static int data_block_equal(void *context, void *value1_le, void *value2_le) +{ + __le64 v1_le, v2_le; + uint64_t b1, b2; + uint32_t t; + + memcpy(&v1_le, value1_le, sizeof(v1_le)); + memcpy(&v2_le, value2_le, sizeof(v2_le)); + unpack_block_time(le64_to_cpu(v1_le), &b1, &t); + unpack_block_time(le64_to_cpu(v2_le), &b2, &t); + + return b1 == b2; +} + +static void subtree_inc(void *context, void *value) +{ + struct dm_btree_info *info = context; + __le64 root_le; + uint64_t root; + + memcpy(&root_le, value, sizeof(root_le)); + root = le64_to_cpu(root_le); + dm_tm_inc(info->tm, root); +} + +static void subtree_dec(void *context, void *value) +{ + struct dm_btree_info *info = context; + __le64 root_le; + uint64_t root; + + memcpy(&root_le, value, sizeof(root_le)); + root = le64_to_cpu(root_le); + if (dm_btree_del(info, root)) + DMERR("btree delete failed\n"); +} + +static int subtree_equal(void *context, void *value1_le, void *value2_le) +{ + __le64 v1_le, v2_le; + memcpy(&v1_le, value1_le, sizeof(v1_le)); + memcpy(&v2_le, value2_le, sizeof(v2_le)); + + return v1_le == v2_le; +} + +/*----------------------------------------------------------------*/ + +static int superblock_all_zeroes(struct dm_block_manager *bm, int *result) +{ + int r; + unsigned i; + struct dm_block *b; + __le64 *data_le, zero = cpu_to_le64(0); + unsigned 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, THIN_SUPERBLOCK_LOCATION, NULL, &b); + if (r) + return r; + + data_le = dm_block_data(b); + *result = 1; + for (i = 0; i < block_size; i++) { + if (data_le[i] != zero) { + *result = 0; + break; + } + } + + return dm_bm_unlock(b); +} + +static int init_pmd(struct dm_pool_metadata *pmd, + struct dm_block_manager *bm, + dm_block_t nr_blocks, int create) +{ + int r; + struct dm_space_map *sm, *data_sm; + struct dm_transaction_manager *tm; + struct dm_block *sblock; + + if (create) { + r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &tm, &sm, &sblock); + if (r < 0) { + DMERR("tm_create_with_sm failed"); + return r; + } + + data_sm = dm_sm_disk_create(tm, nr_blocks); + if (IS_ERR(data_sm)) { + DMERR("sm_disk_create failed"); + r = PTR_ERR(data_sm); + goto bad; + } + } else { + struct thin_disk_superblock *disk_super = NULL; + size_t space_map_root_offset = + offsetof(struct thin_disk_superblock, metadata_space_map_root); + + r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, space_map_root_offset, + SPACE_MAP_ROOT_SIZE, &tm, &sm, &sblock); + if (r < 0) { + DMERR("tm_open_with_sm failed"); + return r; + } + + disk_super = dm_block_data(sblock); + data_sm = dm_sm_disk_open(tm, disk_super->data_space_map_root, + sizeof(disk_super->data_space_map_root)); + if (IS_ERR(data_sm)) { + DMERR("sm_disk_open failed"); + r = PTR_ERR(data_sm); + goto bad; + } + } + + + r = dm_tm_unlock(tm, sblock); + if (r < 0) { + DMERR("couldn't unlock superblock"); + goto bad_data_sm; + } + + pmd->bm = bm; + pmd->metadata_sm = sm; + pmd->data_sm = data_sm; + pmd->tm = tm; + pmd->nb_tm = dm_tm_create_non_blocking_clone(tm); + if (!pmd->nb_tm) { + DMERR("could not create clone tm"); + r = -ENOMEM; + goto bad_data_sm; + } + + pmd->info.tm = tm; + pmd->info.levels = 2; + pmd->info.value_type.context = pmd->data_sm; + pmd->info.value_type.size = sizeof(__le64); + pmd->info.value_type.inc = data_block_inc; + pmd->info.value_type.dec = data_block_dec; + pmd->info.value_type.equal = data_block_equal; + + memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info)); + pmd->nb_info.tm = pmd->nb_tm; + + pmd->tl_info.tm = tm; + pmd->tl_info.levels = 1; + pmd->tl_info.value_type.context = &pmd->info; + pmd->tl_info.value_type.size = sizeof(__le64); + pmd->tl_info.value_type.inc = subtree_inc; + pmd->tl_info.value_type.dec = subtree_dec; + pmd->tl_info.value_type.equal = subtree_equal; + + pmd->bl_info.tm = tm; + pmd->bl_info.levels = 1; + pmd->bl_info.value_type.context = pmd->data_sm; + pmd->bl_info.value_type.size = sizeof(__le64); + pmd->bl_info.value_type.inc = data_block_inc; + pmd->bl_info.value_type.dec = data_block_dec; + pmd->bl_info.value_type.equal = data_block_equal; + + pmd->details_info.tm = tm; + pmd->details_info.levels = 1; + pmd->details_info.value_type.context = NULL; + pmd->details_info.value_type.size = sizeof(struct disk_device_details); + pmd->details_info.value_type.inc = NULL; + pmd->details_info.value_type.dec = NULL; + pmd->details_info.value_type.equal = NULL; + + pmd->root = 0; + + init_rwsem(&pmd->root_lock); + pmd->time = 0; + pmd->need_commit = 0; + pmd->details_root = 0; + pmd->trans_id = 0; + pmd->flags = 0; + INIT_LIST_HEAD(&pmd->thin_devices); + + return 0; + +bad_data_sm: + dm_sm_destroy(data_sm); +bad: + dm_tm_destroy(tm); + dm_sm_destroy(sm); + + return r; +} + +static int __begin_transaction(struct dm_pool_metadata *pmd) +{ + int r; + u32 features; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * __maybe_commit_transaction() resets these + */ + WARN_ON(pmd->need_commit); + + /* + * We re-read the superblock every time. Shouldn't need to do this + * really. + */ + r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + pmd->time = le32_to_cpu(disk_super->time); + pmd->root = le64_to_cpu(disk_super->data_mapping_root); + pmd->details_root = le64_to_cpu(disk_super->device_details_root); + pmd->trans_id = le64_to_cpu(disk_super->trans_id); + pmd->flags = le32_to_cpu(disk_super->flags); + pmd->data_block_size = le32_to_cpu(disk_super->data_block_size); + + features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP; + if (features) { + DMERR("could not access metadata due to " + "unsupported optional features (%lx).", + (unsigned long)features); + r = -EINVAL; + goto out; + } + + /* + * Check for read-only metadata to skip the following RDWR checks. + */ + if (get_disk_ro(pmd->bdev->bd_disk)) + goto out; + + features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP; + if (features) { + DMERR("could not access metadata RDWR due to " + "unsupported optional features (%lx).", + (unsigned long)features); + r = -EINVAL; + } + +out: + dm_bm_unlock(sblock); + return r; +} + +static int __write_changed_details(struct dm_pool_metadata *pmd) +{ + int r; + struct dm_thin_device *td, *tmp; + struct disk_device_details details; + uint64_t key; + + list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) { + if (!td->changed) + continue; + + key = td->id; + + details.mapped_blocks = cpu_to_le64(td->mapped_blocks); + details.transaction_id = cpu_to_le64(td->transaction_id); + details.creation_time = cpu_to_le32(td->creation_time); + details.snapshotted_time = cpu_to_le32(td->snapshotted_time); + __dm_bless_for_disk(&details); + + r = dm_btree_insert(&pmd->details_info, pmd->details_root, + &key, &details, &pmd->details_root); + if (r) + return r; + + if (td->open_count) + td->changed = 0; + else { + list_del(&td->list); + kfree(td); + } + + pmd->need_commit = 1; + } + + return 0; +} + +static int __commit_transaction(struct dm_pool_metadata *pmd) +{ + /* + * FIXME: Associated pool should be made read-only on failure. + */ + int r; + size_t metadata_len, data_len; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * We need to know if the thin_disk_superblock exceeds a 512-byte sector. + */ + BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512); + + r = __write_changed_details(pmd); + if (r < 0) + goto out; + + if (!pmd->need_commit) + goto out; + + r = dm_sm_commit(pmd->data_sm); + if (r < 0) + goto out; + + r = dm_tm_pre_commit(pmd->tm); + if (r < 0) + goto out; + + r = dm_sm_root_size(pmd->metadata_sm, &metadata_len); + if (r < 0) + goto out; + + r = dm_sm_root_size(pmd->metadata_sm, &data_len); + if (r < 0) + goto out; + + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + goto out; + + disk_super = dm_block_data(sblock); + disk_super->time = cpu_to_le32(pmd->time); + disk_super->data_mapping_root = cpu_to_le64(pmd->root); + disk_super->device_details_root = cpu_to_le64(pmd->details_root); + disk_super->trans_id = cpu_to_le64(pmd->trans_id); + disk_super->flags = cpu_to_le32(pmd->flags); + + r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root, + metadata_len); + if (r < 0) + goto out_locked; + + r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root, + data_len); + if (r < 0) + goto out_locked; + + r = dm_tm_commit(pmd->tm, sblock); + if (!r) + pmd->need_commit = 0; + +out: + return r; + +out_locked: + dm_bm_unlock(sblock); + return r; +} + +struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, + sector_t data_block_size) +{ + int r; + struct thin_disk_superblock *disk_super; + struct dm_pool_metadata *pmd; + sector_t bdev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; + struct dm_block_manager *bm; + int create; + struct dm_block *sblock; + + pmd = kmalloc(sizeof(*pmd), GFP_KERNEL); + if (!pmd) { + DMERR("could not allocate metadata struct"); + return ERR_PTR(-ENOMEM); + } + + /* + * Max hex locks: + * 3 for btree insert + + * 2 for btree lookup used within space map + */ + bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE, + THIN_METADATA_CACHE_SIZE, 5); + if (!bm) { + DMERR("could not create block manager"); + kfree(pmd); + return ERR_PTR(-ENOMEM); + } + + r = superblock_all_zeroes(bm, &create); + if (r) { + dm_block_manager_destroy(bm); + kfree(pmd); + return ERR_PTR(r); + } + + + r = init_pmd(pmd, bm, 0, create); + if (r) { + dm_block_manager_destroy(bm); + kfree(pmd); + return ERR_PTR(r); + } + pmd->bdev = bdev; + + if (!create) { + r = __begin_transaction(pmd); + if (r < 0) + goto bad; + return pmd; + } + + /* + * Create. + */ + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + goto bad; + + disk_super = dm_block_data(sblock); + disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC); + disk_super->version = cpu_to_le32(THIN_VERSION); + disk_super->time = 0; + disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); + disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT); + disk_super->data_block_size = cpu_to_le32(data_block_size); + + r = dm_bm_unlock(sblock); + if (r < 0) + goto bad; + + r = dm_btree_empty(&pmd->info, &pmd->root); + if (r < 0) + goto bad; + + r = dm_btree_empty(&pmd->details_info, &pmd->details_root); + if (r < 0) { + DMERR("couldn't create devices root"); + goto bad; + } + + pmd->flags = 0; + pmd->need_commit = 1; + r = dm_pool_commit_metadata(pmd); + if (r < 0) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + goto bad; + } + + return pmd; + +bad: + if (dm_pool_metadata_close(pmd) < 0) + DMWARN("%s: dm_pool_metadata_close() failed.", __func__); + return ERR_PTR(r); +} + +int dm_pool_metadata_close(struct dm_pool_metadata *pmd) +{ + int r; + unsigned open_devices = 0; + struct dm_thin_device *td, *tmp; + + down_read(&pmd->root_lock); + list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) { + if (td->open_count) + open_devices++; + else { + list_del(&td->list); + kfree(td); + } + } + up_read(&pmd->root_lock); + + if (open_devices) { + DMERR("attempt to close pmd when %u device(s) are still open", + open_devices); + return -EBUSY; + } + + r = __commit_transaction(pmd); + if (r < 0) + DMWARN("%s: __commit_transaction() failed, error = %d", + __func__, r); + + dm_tm_destroy(pmd->tm); + dm_tm_destroy(pmd->nb_tm); + dm_block_manager_destroy(pmd->bm); + dm_sm_destroy(pmd->metadata_sm); + dm_sm_destroy(pmd->data_sm); + kfree(pmd); + + return 0; +} + +static int __open_device(struct dm_pool_metadata *pmd, + dm_thin_id dev, int create, + struct dm_thin_device **td) +{ + int r, changed = 0; + struct dm_thin_device *td2; + uint64_t key = dev; + struct disk_device_details details_le; + + /* + * Check the device isn't already open. + */ + list_for_each_entry(td2, &pmd->thin_devices, list) + if (td2->id == dev) { + td2->open_count++; + *td = td2; + return 0; + } + + /* + * Check the device exists. + */ + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &key, &details_le); + if (r) { + if (r != -ENODATA || !create) + return r; + + changed = 1; + details_le.mapped_blocks = 0; + details_le.transaction_id = cpu_to_le64(pmd->trans_id); + details_le.creation_time = cpu_to_le32(pmd->time); + details_le.snapshotted_time = cpu_to_le32(pmd->time); + } + + *td = kmalloc(sizeof(**td), GFP_NOIO); + if (!*td) + return -ENOMEM; + + (*td)->pmd = pmd; + (*td)->id = dev; + (*td)->open_count = 1; + (*td)->changed = changed; + (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks); + (*td)->transaction_id = le64_to_cpu(details_le.transaction_id); + (*td)->creation_time = le32_to_cpu(details_le.creation_time); + (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time); + + list_add(&(*td)->list, &pmd->thin_devices); + + return 0; +} + +static void __close_device(struct dm_thin_device *td) +{ + --td->open_count; +} + +static int __create_thin(struct dm_pool_metadata *pmd, + dm_thin_id dev) +{ + int r; + dm_block_t dev_root; + uint64_t key = dev; + struct disk_device_details details_le; + struct dm_thin_device *td; + __le64 value; + + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &key, &details_le); + if (!r) + return -EEXIST; + + /* + * Create an empty btree for the mappings. + */ + r = dm_btree_empty(&pmd->bl_info, &dev_root); + if (r) + return r; + + /* + * Insert it into the main mapping tree. + */ + value = cpu_to_le64(dev_root); + __dm_bless_for_disk(&value); + r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root); + if (r) { + dm_btree_del(&pmd->bl_info, dev_root); + return r; + } + + r = __open_device(pmd, dev, 1, &td); + if (r) { + __close_device(td); + dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + dm_btree_del(&pmd->bl_info, dev_root); + return r; + } + td->changed = 1; + __close_device(td); + + return r; +} + +int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev) +{ + int r; + + down_write(&pmd->root_lock); + r = __create_thin(pmd, dev); + up_write(&pmd->root_lock); + + return r; +} + +static int __set_snapshot_details(struct dm_pool_metadata *pmd, + struct dm_thin_device *snap, + dm_thin_id origin, uint32_t time) +{ + int r; + struct dm_thin_device *td; + + r = __open_device(pmd, origin, 0, &td); + if (r) + return r; + + td->changed = 1; + td->snapshotted_time = time; + + snap->mapped_blocks = td->mapped_blocks; + snap->snapshotted_time = time; + __close_device(td); + + return 0; +} + +static int __create_snap(struct dm_pool_metadata *pmd, + dm_thin_id dev, dm_thin_id origin) +{ + int r; + dm_block_t origin_root; + uint64_t key = origin, dev_key = dev; + struct dm_thin_device *td; + struct disk_device_details details_le; + __le64 value; + + /* check this device is unused */ + r = dm_btree_lookup(&pmd->details_info, pmd->details_root, + &dev_key, &details_le); + if (!r) + return -EEXIST; + + /* find the mapping tree for the origin */ + r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value); + if (r) + return r; + origin_root = le64_to_cpu(value); + + /* clone the origin, an inc will do */ + dm_tm_inc(pmd->tm, origin_root); + + /* insert into the main mapping tree */ + value = cpu_to_le64(origin_root); + __dm_bless_for_disk(&value); + key = dev; + r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root); + if (r) { + dm_tm_dec(pmd->tm, origin_root); + return r; + } + + pmd->time++; + + r = __open_device(pmd, dev, 1, &td); + if (r) + goto bad; + + r = __set_snapshot_details(pmd, td, origin, pmd->time); + if (r) + goto bad; + + __close_device(td); + return 0; + +bad: + __close_device(td); + dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + dm_btree_remove(&pmd->details_info, pmd->details_root, + &key, &pmd->details_root); + return r; +} + +int dm_pool_create_snap(struct dm_pool_metadata *pmd, + dm_thin_id dev, + dm_thin_id origin) +{ + int r; + + down_write(&pmd->root_lock); + r = __create_snap(pmd, dev, origin); + up_write(&pmd->root_lock); + + return r; +} + +static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev) +{ + int r; + uint64_t key = dev; + struct dm_thin_device *td; + + /* TODO: failure should mark the transaction invalid */ + r = __open_device(pmd, dev, 0, &td); + if (r) + return r; + + if (td->open_count > 1) { + __close_device(td); + return -EBUSY; + } + + list_del(&td->list); + kfree(td); + r = dm_btree_remove(&pmd->details_info, pmd->details_root, + &key, &pmd->details_root); + if (r) + return r; + + r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root); + if (r) + return r; + + pmd->need_commit = 1; + + return 0; +} + +int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd, + dm_thin_id dev) +{ + int r; + + down_write(&pmd->root_lock); + r = __delete_device(pmd, dev); + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t current_id, + uint64_t new_id) +{ + down_write(&pmd->root_lock); + if (pmd->trans_id != current_id) { + up_write(&pmd->root_lock); + DMERR("mismatched transaction id"); + return -EINVAL; + } + + pmd->trans_id = new_id; + pmd->need_commit = 1; + up_write(&pmd->root_lock); + + return 0; +} + +int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd, + uint64_t *result) +{ + down_read(&pmd->root_lock); + *result = pmd->trans_id; + up_read(&pmd->root_lock); + + return 0; +} + +static int __get_held_metadata_root(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + struct thin_disk_superblock *disk_super; + struct dm_block *sblock; + + r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION, + &sb_validator, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + *result = le64_to_cpu(disk_super->held_root); + + return dm_bm_unlock(sblock); +} + +int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = __get_held_metadata_root(pmd, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev, + struct dm_thin_device **td) +{ + int r; + + down_write(&pmd->root_lock); + r = __open_device(pmd, dev, 0, td); + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_close_thin_device(struct dm_thin_device *td) +{ + down_write(&td->pmd->root_lock); + __close_device(td); + up_write(&td->pmd->root_lock); + + return 0; +} + +dm_thin_id dm_thin_dev_id(struct dm_thin_device *td) +{ + return td->id; +} + +static int __snapshotted_since(struct dm_thin_device *td, uint32_t time) +{ + return td->snapshotted_time > time; +} + +int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, + int can_block, struct dm_thin_lookup_result *result) +{ + int r; + uint64_t block_time = 0; + __le64 value; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + if (can_block) { + down_read(&pmd->root_lock); + r = dm_btree_lookup(&pmd->info, pmd->root, keys, &value); + if (!r) + block_time = le64_to_cpu(value); + up_read(&pmd->root_lock); + + } else if (down_read_trylock(&pmd->root_lock)) { + r = dm_btree_lookup(&pmd->nb_info, pmd->root, keys, &value); + if (!r) + block_time = le64_to_cpu(value); + up_read(&pmd->root_lock); + + } else + return -EWOULDBLOCK; + + if (!r) { + dm_block_t exception_block; + uint32_t exception_time; + unpack_block_time(block_time, &exception_block, + &exception_time); + result->block = exception_block; + result->shared = __snapshotted_since(td, exception_time); + } + + return r; +} + +static int __insert(struct dm_thin_device *td, dm_block_t block, + dm_block_t data_block) +{ + int r, inserted; + __le64 value; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + pmd->need_commit = 1; + value = cpu_to_le64(pack_block_time(data_block, pmd->time)); + __dm_bless_for_disk(&value); + + r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value, + &pmd->root, &inserted); + if (r) + return r; + + if (inserted) { + td->mapped_blocks++; + td->changed = 1; + } + + return 0; +} + +int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block, + dm_block_t data_block) +{ + int r; + + down_write(&td->pmd->root_lock); + r = __insert(td, block, data_block); + up_write(&td->pmd->root_lock); + + return r; +} + +static int __remove(struct dm_thin_device *td, dm_block_t block) +{ + int r; + struct dm_pool_metadata *pmd = td->pmd; + dm_block_t keys[2] = { td->id, block }; + + r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root); + if (r) + return r; + + pmd->need_commit = 1; + + return 0; +} + +int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block) +{ + int r; + + down_write(&td->pmd->root_lock); + r = __remove(td, block); + up_write(&td->pmd->root_lock); + + return r; +} + +int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_write(&pmd->root_lock); + + r = dm_sm_new_block(pmd->data_sm, result); + pmd->need_commit = 1; + + up_write(&pmd->root_lock); + + return r; +} + +int dm_pool_commit_metadata(struct dm_pool_metadata *pmd) +{ + int r; + + down_write(&pmd->root_lock); + + r = __commit_transaction(pmd); + if (r <= 0) + goto out; + + /* + * Open the next transaction. + */ + r = __begin_transaction(pmd); +out: + up_write(&pmd->root_lock); + return r; +} + +int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_free(pmd->data_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_free(pmd->metadata_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd, + dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_blocks(pmd->metadata_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result) +{ + down_read(&pmd->root_lock); + *result = pmd->data_block_size; + up_read(&pmd->root_lock); + + return 0; +} + +int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result) +{ + int r; + + down_read(&pmd->root_lock); + r = dm_sm_get_nr_blocks(pmd->data_sm, result); + up_read(&pmd->root_lock); + + return r; +} + +int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result) +{ + struct dm_pool_metadata *pmd = td->pmd; + + down_read(&pmd->root_lock); + *result = td->mapped_blocks; + up_read(&pmd->root_lock); + + return 0; +} + +static int __highest_block(struct dm_thin_device *td, dm_block_t *result) +{ + int r; + __le64 value_le; + dm_block_t thin_root; + struct dm_pool_metadata *pmd = td->pmd; + + r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le); + if (r) + return r; + + thin_root = le64_to_cpu(value_le); + + return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result); +} + +int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, + dm_block_t *result) +{ + int r; + struct dm_pool_metadata *pmd = td->pmd; + + down_read(&pmd->root_lock); + r = __highest_block(td, result); + up_read(&pmd->root_lock); + + return r; +} + +static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count) +{ + int r; + dm_block_t old_count; + + r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count); + if (r) + return r; + + if (new_count == old_count) + return 0; + + if (new_count < old_count) { + DMERR("cannot reduce size of data device"); + return -EINVAL; + } + + r = dm_sm_extend(pmd->data_sm, new_count - old_count); + if (!r) + pmd->need_commit = 1; + + return r; +} + +int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count) +{ + int r; + + down_write(&pmd->root_lock); + r = __resize_data_dev(pmd, new_count); + up_write(&pmd->root_lock); + + return r; +} |