diff options
Diffstat (limited to 'drivers/md/dm-clone-metadata.c')
| -rw-r--r-- | drivers/md/dm-clone-metadata.c | 964 |
1 files changed, 964 insertions, 0 deletions
diff --git a/drivers/md/dm-clone-metadata.c b/drivers/md/dm-clone-metadata.c new file mode 100644 index 000000000000..6bc8c1d1c351 --- /dev/null +++ b/drivers/md/dm-clone-metadata.c @@ -0,0 +1,964 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2019 Arrikto, Inc. All Rights Reserved. + */ + +#include <linux/mm.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/rwsem.h> +#include <linux/bitops.h> +#include <linux/bitmap.h> +#include <linux/device-mapper.h> + +#include "persistent-data/dm-bitset.h" +#include "persistent-data/dm-space-map.h" +#include "persistent-data/dm-block-manager.h" +#include "persistent-data/dm-transaction-manager.h" + +#include "dm-clone-metadata.h" + +#define DM_MSG_PREFIX "clone metadata" + +#define SUPERBLOCK_LOCATION 0 +#define SUPERBLOCK_MAGIC 0x8af27f64 +#define SUPERBLOCK_CSUM_XOR 257649492 + +#define DM_CLONE_MAX_CONCURRENT_LOCKS 5 + +#define UUID_LEN 16 + +/* Min and max dm-clone metadata versions supported */ +#define DM_CLONE_MIN_METADATA_VERSION 1 +#define DM_CLONE_MAX_METADATA_VERSION 1 + +/* + * On-disk metadata layout + */ +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]; + + __le64 region_size; + __le64 target_size; + + __le64 bitset_root; +} __packed; + +/* + * Region and Dirty bitmaps. + * + * dm-clone logically splits the source and destination devices in regions of + * fixed size. The destination device's regions are gradually hydrated, i.e., + * we copy (clone) the source's regions to the destination device. Eventually, + * all regions will get hydrated and all I/O will be served from the + * destination device. + * + * We maintain an on-disk bitmap which tracks the state of each of the + * destination device's regions, i.e., whether they are hydrated or not. + * + * To save constantly doing look ups on disk we keep an in core copy of the + * on-disk bitmap, the region_map. + * + * To further reduce metadata I/O overhead we use a second bitmap, the dmap + * (dirty bitmap), which tracks the dirty words, i.e. longs, of the region_map. + * + * When a region finishes hydrating dm-clone calls + * dm_clone_set_region_hydrated(), or for discard requests + * dm_clone_cond_set_range(), which sets the corresponding bits in region_map + * and dmap. + * + * During a metadata commit we scan the dmap for dirty region_map words (longs) + * and update accordingly the on-disk metadata. Thus, we don't have to flush to + * disk the whole region_map. We can just flush the dirty region_map words. + * + * We use a dirty bitmap, which is smaller than the original region_map, to + * reduce the amount of memory accesses during a metadata commit. As dm-bitset + * accesses the on-disk bitmap in 64-bit word granularity, there is no + * significant benefit in tracking the dirty region_map bits with a smaller + * granularity. + * + * We could update directly the on-disk bitmap, when dm-clone calls either + * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), buts this + * inserts significant metadata I/O overhead in dm-clone's I/O path. Also, as + * these two functions don't block, we can call them in interrupt context, + * e.g., in a hooked overwrite bio's completion routine, and further reduce the + * I/O completion latency. + * + * We maintain two dirty bitmaps. During a metadata commit we atomically swap + * the currently used dmap with the unused one. This allows the metadata update + * functions to run concurrently with an ongoing commit. + */ +struct dirty_map { + unsigned long *dirty_words; + unsigned int changed; +}; + +struct dm_clone_metadata { + /* The metadata block device */ + struct block_device *bdev; + + sector_t target_size; + sector_t region_size; + unsigned long nr_regions; + unsigned long nr_words; + + /* Spinlock protecting the region and dirty bitmaps. */ + spinlock_t bitmap_lock; + struct dirty_map dmap[2]; + struct dirty_map *current_dmap; + + /* + * In core copy of the on-disk bitmap to save constantly doing look ups + * on disk. + */ + unsigned long *region_map; + + /* Protected by bitmap_lock */ + unsigned int read_only; + + struct dm_block_manager *bm; + struct dm_space_map *sm; + struct dm_transaction_manager *tm; + + struct rw_semaphore lock; + + struct dm_disk_bitset bitset_info; + dm_block_t bitset_root; + + /* + * 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]; + + bool hydration_done:1; + bool fail_io:1; +}; + +/*---------------------------------------------------------------------------*/ + +/* + * 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 *sb; + u32 csum; + + sb = dm_block_data(b); + sb->blocknr = cpu_to_le64(dm_block_location(b)); + + csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR); + sb->csum = cpu_to_le32(csum); +} + +static int sb_check(struct dm_block_validator *v, struct dm_block *b, + size_t sb_block_size) +{ + struct superblock_disk *sb; + u32 csum, metadata_version; + + sb = dm_block_data(b); + + if (dm_block_location(b) != le64_to_cpu(sb->blocknr)) { + DMERR("Superblock check failed: blocknr %llu, expected %llu", + le64_to_cpu(sb->blocknr), + (unsigned long long)dm_block_location(b)); + return -ENOTBLK; + } + + if (le64_to_cpu(sb->magic) != SUPERBLOCK_MAGIC) { + DMERR("Superblock check failed: magic %llu, expected %llu", + le64_to_cpu(sb->magic), + (unsigned long long)SUPERBLOCK_MAGIC); + return -EILSEQ; + } + + csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR); + if (sb->csum != cpu_to_le32(csum)) { + DMERR("Superblock check failed: checksum %u, expected %u", + csum, le32_to_cpu(sb->csum)); + return -EILSEQ; + } + + /* Check metadata version */ + metadata_version = le32_to_cpu(sb->version); + if (metadata_version < DM_CLONE_MIN_METADATA_VERSION || + metadata_version > DM_CLONE_MAX_METADATA_VERSION) { + DMERR("Clone metadata version %u found, but only versions between %u and %u supported.", + metadata_version, DM_CLONE_MIN_METADATA_VERSION, + DM_CLONE_MAX_METADATA_VERSION); + return -EINVAL; + } + + return 0; +} + +static struct dm_block_validator sb_validator = { + .name = "superblock", + .prepare_for_write = sb_prepare_for_write, + .check = sb_check +}; + +/* + * Check if the superblock is formatted or not. We consider the superblock to + * be formatted in case we find non-zero bytes in it. + */ +static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *formatted) +{ + int r; + unsigned int i, nr_words; + struct dm_block *sblock; + __le64 *data_le, zero = cpu_to_le64(0); + + /* + * We don't use a validator here because the superblock could be all + * zeroes. + */ + r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &sblock); + if (r) { + DMERR("Failed to read_lock superblock"); + return r; + } + + data_le = dm_block_data(sblock); + *formatted = false; + + /* This assumes that the block size is a multiple of 8 bytes */ + BUG_ON(dm_bm_block_size(bm) % sizeof(__le64)); + nr_words = dm_bm_block_size(bm) / sizeof(__le64); + for (i = 0; i < nr_words; i++) { + if (data_le[i] != zero) { + *formatted = true; + break; + } + } + + dm_bm_unlock(sblock); + + return 0; +} + +/*---------------------------------------------------------------------------*/ + +/* + * Low-level metadata handling. + */ +static inline int superblock_read_lock(struct dm_clone_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_read_lock(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); +} + +static inline int superblock_write_lock(struct dm_clone_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_write_lock(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); +} + +static inline int superblock_write_lock_zero(struct dm_clone_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_write_lock_zero(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock); +} + +static int __copy_sm_root(struct dm_clone_metadata *cmd) +{ + int r; + size_t root_size; + + r = dm_sm_root_size(cmd->sm, &root_size); + if (r) + return r; + + return dm_sm_copy_root(cmd->sm, &cmd->metadata_space_map_root, root_size); +} + +/* Save dm-clone metadata in superblock */ +static void __prepare_superblock(struct dm_clone_metadata *cmd, + struct superblock_disk *sb) +{ + sb->flags = cpu_to_le32(0UL); + + /* FIXME: UUID is currently unused */ + memset(sb->uuid, 0, sizeof(sb->uuid)); + + sb->magic = cpu_to_le64(SUPERBLOCK_MAGIC); + sb->version = cpu_to_le32(DM_CLONE_MAX_METADATA_VERSION); + + /* Save the metadata space_map root */ + memcpy(&sb->metadata_space_map_root, &cmd->metadata_space_map_root, + sizeof(cmd->metadata_space_map_root)); + + sb->region_size = cpu_to_le64(cmd->region_size); + sb->target_size = cpu_to_le64(cmd->target_size); + sb->bitset_root = cpu_to_le64(cmd->bitset_root); +} + +static int __open_metadata(struct dm_clone_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct superblock_disk *sb; + + r = superblock_read_lock(cmd, &sblock); + + if (r) { + DMERR("Failed to read_lock superblock"); + return r; + } + + sb = dm_block_data(sblock); + + /* Verify that target_size and region_size haven't changed. */ + if (cmd->region_size != le64_to_cpu(sb->region_size) || + cmd->target_size != le64_to_cpu(sb->target_size)) { + DMERR("Region and/or target size don't match the ones in metadata"); + r = -EINVAL; + goto out_with_lock; + } + + r = dm_tm_open_with_sm(cmd->bm, SUPERBLOCK_LOCATION, + sb->metadata_space_map_root, + sizeof(sb->metadata_space_map_root), + &cmd->tm, &cmd->sm); + + if (r) { + DMERR("dm_tm_open_with_sm failed"); + goto out_with_lock; + } + + dm_disk_bitset_init(cmd->tm, &cmd->bitset_info); + cmd->bitset_root = le64_to_cpu(sb->bitset_root); + +out_with_lock: + dm_bm_unlock(sblock); + + return r; +} + +static int __format_metadata(struct dm_clone_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct superblock_disk *sb; + + r = dm_tm_create_with_sm(cmd->bm, SUPERBLOCK_LOCATION, &cmd->tm, &cmd->sm); + if (r) { + DMERR("Failed to create transaction manager"); + return r; + } + + dm_disk_bitset_init(cmd->tm, &cmd->bitset_info); + + r = dm_bitset_empty(&cmd->bitset_info, &cmd->bitset_root); + if (r) { + DMERR("Failed to create empty on-disk bitset"); + goto err_with_tm; + } + + r = dm_bitset_resize(&cmd->bitset_info, cmd->bitset_root, 0, + cmd->nr_regions, false, &cmd->bitset_root); + if (r) { + DMERR("Failed to resize on-disk bitset to %lu entries", cmd->nr_regions); + goto err_with_tm; + } + + /* Flush to disk all blocks, except the superblock */ + r = dm_tm_pre_commit(cmd->tm); + if (r) { + DMERR("dm_tm_pre_commit failed"); + goto err_with_tm; + } + + r = __copy_sm_root(cmd); + if (r) { + DMERR("__copy_sm_root failed"); + goto err_with_tm; + } + + r = superblock_write_lock_zero(cmd, &sblock); + if (r) { + DMERR("Failed to write_lock superblock"); + goto err_with_tm; + } + + sb = dm_block_data(sblock); + __prepare_superblock(cmd, sb); + r = dm_tm_commit(cmd->tm, sblock); + if (r) { + DMERR("Failed to commit superblock"); + goto err_with_tm; + } + + return 0; + +err_with_tm: + dm_sm_destroy(cmd->sm); + dm_tm_destroy(cmd->tm); + + return r; +} + +static int __open_or_format_metadata(struct dm_clone_metadata *cmd, bool may_format_device) +{ + int r; + bool formatted = false; + + r = __superblock_all_zeroes(cmd->bm, &formatted); + if (r) + return r; + + if (!formatted) + return may_format_device ? __format_metadata(cmd) : -EPERM; + + return __open_metadata(cmd); +} + +static int __create_persistent_data_structures(struct dm_clone_metadata *cmd, + bool may_format_device) +{ + int r; + + /* Create block manager */ + cmd->bm = dm_block_manager_create(cmd->bdev, + DM_CLONE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, + DM_CLONE_MAX_CONCURRENT_LOCKS); + if (IS_ERR(cmd->bm)) { + DMERR("Failed to create block manager"); + return PTR_ERR(cmd->bm); + } + + r = __open_or_format_metadata(cmd, may_format_device); + if (r) + dm_block_manager_destroy(cmd->bm); + + return r; +} + +static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd) +{ + dm_sm_destroy(cmd->sm); + dm_tm_destroy(cmd->tm); + dm_block_manager_destroy(cmd->bm); +} + +/*---------------------------------------------------------------------------*/ + +static size_t bitmap_size(unsigned long nr_bits) +{ + return BITS_TO_LONGS(nr_bits) * sizeof(long); +} + +static int dirty_map_init(struct dm_clone_metadata *cmd) +{ + cmd->dmap[0].changed = 0; + cmd->dmap[0].dirty_words = kvzalloc(bitmap_size(cmd->nr_words), GFP_KERNEL); + + if (!cmd->dmap[0].dirty_words) { + DMERR("Failed to allocate dirty bitmap"); + return -ENOMEM; + } + + cmd->dmap[1].changed = 0; + cmd->dmap[1].dirty_words = kvzalloc(bitmap_size(cmd->nr_words), GFP_KERNEL); + + if (!cmd->dmap[1].dirty_words) { + DMERR("Failed to allocate dirty bitmap"); + kvfree(cmd->dmap[0].dirty_words); + return -ENOMEM; + } + + cmd->current_dmap = &cmd->dmap[0]; + + return 0; +} + +static void dirty_map_exit(struct dm_clone_metadata *cmd) +{ + kvfree(cmd->dmap[0].dirty_words); + kvfree(cmd->dmap[1].dirty_words); +} + +static int __load_bitset_in_core(struct dm_clone_metadata *cmd) +{ + int r; + unsigned long i; + struct dm_bitset_cursor c; + + /* Flush bitset cache */ + r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root); + if (r) + return r; + + r = dm_bitset_cursor_begin(&cmd->bitset_info, cmd->bitset_root, cmd->nr_regions, &c); + if (r) + return r; + + for (i = 0; ; i++) { + if (dm_bitset_cursor_get_value(&c)) + __set_bit(i, cmd->region_map); + else + __clear_bit(i, cmd->region_map); + + if (i >= (cmd->nr_regions - 1)) + break; + + r = dm_bitset_cursor_next(&c); + + if (r) + break; + } + + dm_bitset_cursor_end(&c); + + return r; +} + +struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev, + sector_t target_size, + sector_t region_size) +{ + int r; + struct dm_clone_metadata *cmd; + + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) { + DMERR("Failed to allocate memory for dm-clone metadata"); + return ERR_PTR(-ENOMEM); + } + + cmd->bdev = bdev; + cmd->target_size = target_size; + cmd->region_size = region_size; + cmd->nr_regions = dm_sector_div_up(cmd->target_size, cmd->region_size); + cmd->nr_words = BITS_TO_LONGS(cmd->nr_regions); + + init_rwsem(&cmd->lock); + spin_lock_init(&cmd->bitmap_lock); + cmd->read_only = 0; + cmd->fail_io = false; + cmd->hydration_done = false; + + cmd->region_map = kvmalloc(bitmap_size(cmd->nr_regions), GFP_KERNEL); + if (!cmd->region_map) { + DMERR("Failed to allocate memory for region bitmap"); + r = -ENOMEM; + goto out_with_md; + } + + r = __create_persistent_data_structures(cmd, true); + if (r) + goto out_with_region_map; + + r = __load_bitset_in_core(cmd); + if (r) { + DMERR("Failed to load on-disk region map"); + goto out_with_pds; + } + + r = dirty_map_init(cmd); + if (r) + goto out_with_pds; + + if (bitmap_full(cmd->region_map, cmd->nr_regions)) + cmd->hydration_done = true; + + return cmd; + +out_with_pds: + __destroy_persistent_data_structures(cmd); + +out_with_region_map: + kvfree(cmd->region_map); + +out_with_md: + kfree(cmd); + + return ERR_PTR(r); +} + +void dm_clone_metadata_close(struct dm_clone_metadata *cmd) +{ + if (!cmd->fail_io) + __destroy_persistent_data_structures(cmd); + + dirty_map_exit(cmd); + kvfree(cmd->region_map); + kfree(cmd); +} + +bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd) +{ + return cmd->hydration_done; +} + +bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr) +{ + return dm_clone_is_hydration_done(cmd) || test_bit(region_nr, cmd->region_map); +} + +bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd, + unsigned long start, unsigned long nr_regions) +{ + unsigned long bit; + + if (dm_clone_is_hydration_done(cmd)) + return true; + + bit = find_next_zero_bit(cmd->region_map, cmd->nr_regions, start); + + return (bit >= (start + nr_regions)); +} + +unsigned long dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd) +{ + return bitmap_weight(cmd->region_map, cmd->nr_regions); +} + +unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd, + unsigned long start) +{ + return find_next_zero_bit(cmd->region_map, cmd->nr_regions, start); +} + +static int __update_metadata_word(struct dm_clone_metadata *cmd, unsigned long word) +{ + int r; + unsigned long index = word * BITS_PER_LONG; + unsigned long max_index = min(cmd->nr_regions, (word + 1) * BITS_PER_LONG); + + while (index < max_index) { + if (test_bit(index, cmd->region_map)) { + r = dm_bitset_set_bit(&cmd->bitset_info, cmd->bitset_root, + index, &cmd->bitset_root); + + if (r) { + DMERR("dm_bitset_set_bit failed"); + return r; + } + } + index++; + } + + return 0; +} + +static int __metadata_commit(struct dm_clone_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct superblock_disk *sb; + + /* Flush bitset cache */ + r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root); + if (r) { + DMERR("dm_bitset_flush failed"); + return r; + } + + /* Flush to disk all blocks, except the superblock */ + r = dm_tm_pre_commit(cmd->tm); + if (r) { + DMERR("dm_tm_pre_commit failed"); + return r; + } + + /* Save the space map root in cmd->metadata_space_map_root */ + r = __copy_sm_root(cmd); + if (r) { + DMERR("__copy_sm_root failed"); + return r; + } + + /* Lock the superblock */ + r = superblock_write_lock_zero(cmd, &sblock); + if (r) { + DMERR("Failed to write_lock superblock"); + return r; + } + + /* Save the metadata in superblock */ + sb = dm_block_data(sblock); + __prepare_superblock(cmd, sb); + + /* Unlock superblock and commit it to disk */ + r = dm_tm_commit(cmd->tm, sblock); + if (r) { + DMERR("Failed to commit superblock"); + return r; + } + + /* + * FIXME: Find a more efficient way to check if the hydration is done. + */ + if (bitmap_full(cmd->region_map, cmd->nr_regions)) + cmd->hydration_done = true; + + return 0; +} + +static int __flush_dmap(struct dm_clone_metadata *cmd, struct dirty_map *dmap) +{ + int r; + unsigned long word, flags; + + word = 0; + do { + word = find_next_bit(dmap->dirty_words, cmd->nr_words, word); + + if (word == cmd->nr_words) + break; + + r = __update_metadata_word(cmd, word); + + if (r) + return r; + + __clear_bit(word, dmap->dirty_words); + word++; + } while (word < cmd->nr_words); + + r = __metadata_commit(cmd); + + if (r) + return r; + + /* Update the changed flag */ + spin_lock_irqsave(&cmd->bitmap_lock, flags); + dmap->changed = 0; + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + return 0; +} + +int dm_clone_metadata_commit(struct dm_clone_metadata *cmd) +{ + int r = -EPERM; + unsigned long flags; + struct dirty_map *dmap, *next_dmap; + + down_write(&cmd->lock); + + if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) + goto out; + + /* Get current dirty bitmap */ + dmap = cmd->current_dmap; + + /* Get next dirty bitmap */ + next_dmap = (dmap == &cmd->dmap[0]) ? &cmd->dmap[1] : &cmd->dmap[0]; + + /* + * The last commit failed, so we don't have a clean dirty-bitmap to + * use. + */ + if (WARN_ON(next_dmap->changed)) { + r = -EINVAL; + goto out; + } + + /* Swap dirty bitmaps */ + spin_lock_irqsave(&cmd->bitmap_lock, flags); + cmd->current_dmap = next_dmap; + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + /* + * No one is accessing the old dirty bitmap anymore, so we can flush + * it. + */ + r = __flush_dmap(cmd, dmap); +out: + up_write(&cmd->lock); + + return r; +} + +int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr) +{ + int r = 0; + struct dirty_map *dmap; + unsigned long word, flags; + + word = region_nr / BITS_PER_LONG; + + spin_lock_irqsave(&cmd->bitmap_lock, flags); + + if (cmd->read_only) { + r = -EPERM; + goto out; + } + + dmap = cmd->current_dmap; + + __set_bit(word, dmap->dirty_words); + __set_bit(region_nr, cmd->region_map); + dmap->changed = 1; + +out: + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + return r; +} + +int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start, + unsigned long nr_regions) +{ + int r = 0; + struct dirty_map *dmap; + unsigned long word, region_nr, flags; + + spin_lock_irqsave(&cmd->bitmap_lock, flags); + + if (cmd->read_only) { + r = -EPERM; + goto out; + } + + dmap = cmd->current_dmap; + for (region_nr = start; region_nr < (start + nr_regions); region_nr++) { + if (!test_bit(region_nr, cmd->region_map)) { + word = region_nr / BITS_PER_LONG; + __set_bit(word, dmap->dirty_words); + __set_bit(region_nr, cmd->region_map); + dmap->changed = 1; + } + } +out: + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + return r; +} + +/* + * WARNING: This must not be called concurrently with either + * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it changes + * cmd->region_map without taking the cmd->bitmap_lock spinlock. The only + * exception is after setting the metadata to read-only mode, using + * dm_clone_metadata_set_read_only(). + * + * We don't take the spinlock because __load_bitset_in_core() does I/O, so it + * may block. + */ +int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd) +{ + int r = -EINVAL; + + down_write(&cmd->lock); + + if (cmd->fail_io) + goto out; + + r = __load_bitset_in_core(cmd); +out: + up_write(&cmd->lock); + + return r; +} + +bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd) +{ + bool r; + unsigned long flags; + + spin_lock_irqsave(&cmd->bitmap_lock, flags); + r = cmd->dmap[0].changed || cmd->dmap[1].changed; + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + return r; +} + +int dm_clone_metadata_abort(struct dm_clone_metadata *cmd) +{ + int r = -EPERM; + + down_write(&cmd->lock); + + if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) + goto out; + + __destroy_persistent_data_structures(cmd); + + r = __create_persistent_data_structures(cmd, false); + if (r) { + /* If something went wrong we can neither write nor read the metadata */ + cmd->fail_io = true; + } +out: + up_write(&cmd->lock); + + return r; +} + +void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd) +{ + unsigned long flags; + + down_write(&cmd->lock); + + spin_lock_irqsave(&cmd->bitmap_lock, flags); + cmd->read_only = 1; + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + if (!cmd->fail_io) + dm_bm_set_read_only(cmd->bm); + + up_write(&cmd->lock); +} + +void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd) +{ + unsigned long flags; + + down_write(&cmd->lock); + + spin_lock_irqsave(&cmd->bitmap_lock, flags); + cmd->read_only = 0; + spin_unlock_irqrestore(&cmd->bitmap_lock, flags); + + if (!cmd->fail_io) + dm_bm_set_read_write(cmd->bm); + + up_write(&cmd->lock); +} + +int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, + dm_block_t *result) +{ + int r = -EINVAL; + + down_read(&cmd->lock); + + if (!cmd->fail_io) + r = dm_sm_get_nr_free(cmd->sm, result); + + up_read(&cmd->lock); + + return r; +} + +int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, + dm_block_t *result) +{ + int r = -EINVAL; + + down_read(&cmd->lock); + + if (!cmd->fail_io) + r = dm_sm_get_nr_blocks(cmd->sm, result); + + up_read(&cmd->lock); + + return r; +} |