diff options
Diffstat (limited to 'drivers/nvdimm/btt.c')
| -rw-r--r-- | drivers/nvdimm/btt.c | 1479 |
1 files changed, 1479 insertions, 0 deletions
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c new file mode 100644 index 000000000000..411c7b2bb37a --- /dev/null +++ b/drivers/nvdimm/btt.c @@ -0,0 +1,1479 @@ +/* + * Block Translation Table + * Copyright (c) 2014-2015, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include <linux/highmem.h> +#include <linux/debugfs.h> +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/mutex.h> +#include <linux/hdreg.h> +#include <linux/genhd.h> +#include <linux/sizes.h> +#include <linux/ndctl.h> +#include <linux/fs.h> +#include <linux/nd.h> +#include "btt.h" +#include "nd.h" + +enum log_ent_request { + LOG_NEW_ENT = 0, + LOG_OLD_ENT +}; + +static int btt_major; + +static int arena_read_bytes(struct arena_info *arena, resource_size_t offset, + void *buf, size_t n) +{ + struct nd_btt *nd_btt = arena->nd_btt; + struct nd_namespace_common *ndns = nd_btt->ndns; + + /* arena offsets are 4K from the base of the device */ + offset += SZ_4K; + return nvdimm_read_bytes(ndns, offset, buf, n); +} + +static int arena_write_bytes(struct arena_info *arena, resource_size_t offset, + void *buf, size_t n) +{ + struct nd_btt *nd_btt = arena->nd_btt; + struct nd_namespace_common *ndns = nd_btt->ndns; + + /* arena offsets are 4K from the base of the device */ + offset += SZ_4K; + return nvdimm_write_bytes(ndns, offset, buf, n); +} + +static int btt_info_write(struct arena_info *arena, struct btt_sb *super) +{ + int ret; + + ret = arena_write_bytes(arena, arena->info2off, super, + sizeof(struct btt_sb)); + if (ret) + return ret; + + return arena_write_bytes(arena, arena->infooff, super, + sizeof(struct btt_sb)); +} + +static int btt_info_read(struct arena_info *arena, struct btt_sb *super) +{ + WARN_ON(!super); + return arena_read_bytes(arena, arena->infooff, super, + sizeof(struct btt_sb)); +} + +/* + * 'raw' version of btt_map write + * Assumptions: + * mapping is in little-endian + * mapping contains 'E' and 'Z' flags as desired + */ +static int __btt_map_write(struct arena_info *arena, u32 lba, __le32 mapping) +{ + u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE); + + WARN_ON(lba >= arena->external_nlba); + return arena_write_bytes(arena, ns_off, &mapping, MAP_ENT_SIZE); +} + +static int btt_map_write(struct arena_info *arena, u32 lba, u32 mapping, + u32 z_flag, u32 e_flag) +{ + u32 ze; + __le32 mapping_le; + + /* + * This 'mapping' is supposed to be just the LBA mapping, without + * any flags set, so strip the flag bits. + */ + mapping &= MAP_LBA_MASK; + + ze = (z_flag << 1) + e_flag; + switch (ze) { + case 0: + /* + * We want to set neither of the Z or E flags, and + * in the actual layout, this means setting the bit + * positions of both to '1' to indicate a 'normal' + * map entry + */ + mapping |= MAP_ENT_NORMAL; + break; + case 1: + mapping |= (1 << MAP_ERR_SHIFT); + break; + case 2: + mapping |= (1 << MAP_TRIM_SHIFT); + break; + default: + /* + * The case where Z and E are both sent in as '1' could be + * construed as a valid 'normal' case, but we decide not to, + * to avoid confusion + */ + WARN_ONCE(1, "Invalid use of Z and E flags\n"); + return -EIO; + } + + mapping_le = cpu_to_le32(mapping); + return __btt_map_write(arena, lba, mapping_le); +} + +static int btt_map_read(struct arena_info *arena, u32 lba, u32 *mapping, + int *trim, int *error) +{ + int ret; + __le32 in; + u32 raw_mapping, postmap, ze, z_flag, e_flag; + u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE); + + WARN_ON(lba >= arena->external_nlba); + + ret = arena_read_bytes(arena, ns_off, &in, MAP_ENT_SIZE); + if (ret) + return ret; + + raw_mapping = le32_to_cpu(in); + + z_flag = (raw_mapping & MAP_TRIM_MASK) >> MAP_TRIM_SHIFT; + e_flag = (raw_mapping & MAP_ERR_MASK) >> MAP_ERR_SHIFT; + ze = (z_flag << 1) + e_flag; + postmap = raw_mapping & MAP_LBA_MASK; + + /* Reuse the {z,e}_flag variables for *trim and *error */ + z_flag = 0; + e_flag = 0; + + switch (ze) { + case 0: + /* Initial state. Return postmap = premap */ + *mapping = lba; + break; + case 1: + *mapping = postmap; + e_flag = 1; + break; + case 2: + *mapping = postmap; + z_flag = 1; + break; + case 3: + *mapping = postmap; + break; + default: + return -EIO; + } + + if (trim) + *trim = z_flag; + if (error) + *error = e_flag; + + return ret; +} + +static int btt_log_read_pair(struct arena_info *arena, u32 lane, + struct log_entry *ent) +{ + WARN_ON(!ent); + return arena_read_bytes(arena, + arena->logoff + (2 * lane * LOG_ENT_SIZE), ent, + 2 * LOG_ENT_SIZE); +} + +static struct dentry *debugfs_root; + +static void arena_debugfs_init(struct arena_info *a, struct dentry *parent, + int idx) +{ + char dirname[32]; + struct dentry *d; + + /* If for some reason, parent bttN was not created, exit */ + if (!parent) + return; + + snprintf(dirname, 32, "arena%d", idx); + d = debugfs_create_dir(dirname, parent); + if (IS_ERR_OR_NULL(d)) + return; + a->debugfs_dir = d; + + debugfs_create_x64("size", S_IRUGO, d, &a->size); + debugfs_create_x64("external_lba_start", S_IRUGO, d, + &a->external_lba_start); + debugfs_create_x32("internal_nlba", S_IRUGO, d, &a->internal_nlba); + debugfs_create_u32("internal_lbasize", S_IRUGO, d, + &a->internal_lbasize); + debugfs_create_x32("external_nlba", S_IRUGO, d, &a->external_nlba); + debugfs_create_u32("external_lbasize", S_IRUGO, d, + &a->external_lbasize); + debugfs_create_u32("nfree", S_IRUGO, d, &a->nfree); + debugfs_create_u16("version_major", S_IRUGO, d, &a->version_major); + debugfs_create_u16("version_minor", S_IRUGO, d, &a->version_minor); + debugfs_create_x64("nextoff", S_IRUGO, d, &a->nextoff); + debugfs_create_x64("infooff", S_IRUGO, d, &a->infooff); + debugfs_create_x64("dataoff", S_IRUGO, d, &a->dataoff); + debugfs_create_x64("mapoff", S_IRUGO, d, &a->mapoff); + debugfs_create_x64("logoff", S_IRUGO, d, &a->logoff); + debugfs_create_x64("info2off", S_IRUGO, d, &a->info2off); + debugfs_create_x32("flags", S_IRUGO, d, &a->flags); +} + +static void btt_debugfs_init(struct btt *btt) +{ + int i = 0; + struct arena_info *arena; + + btt->debugfs_dir = debugfs_create_dir(dev_name(&btt->nd_btt->dev), + debugfs_root); + if (IS_ERR_OR_NULL(btt->debugfs_dir)) + return; + + list_for_each_entry(arena, &btt->arena_list, list) { + arena_debugfs_init(arena, btt->debugfs_dir, i); + i++; + } +} + +/* + * This function accepts two log entries, and uses the + * sequence number to find the 'older' entry. + * It also updates the sequence number in this old entry to + * make it the 'new' one if the mark_flag is set. + * Finally, it returns which of the entries was the older one. + * + * TODO The logic feels a bit kludge-y. make it better.. + */ +static int btt_log_get_old(struct log_entry *ent) +{ + int old; + + /* + * the first ever time this is seen, the entry goes into [0] + * the next time, the following logic works out to put this + * (next) entry into [1] + */ + if (ent[0].seq == 0) { + ent[0].seq = cpu_to_le32(1); + return 0; + } + + if (ent[0].seq == ent[1].seq) + return -EINVAL; + if (le32_to_cpu(ent[0].seq) + le32_to_cpu(ent[1].seq) > 5) + return -EINVAL; + + if (le32_to_cpu(ent[0].seq) < le32_to_cpu(ent[1].seq)) { + if (le32_to_cpu(ent[1].seq) - le32_to_cpu(ent[0].seq) == 1) + old = 0; + else + old = 1; + } else { + if (le32_to_cpu(ent[0].seq) - le32_to_cpu(ent[1].seq) == 1) + old = 1; + else + old = 0; + } + + return old; +} + +static struct device *to_dev(struct arena_info *arena) +{ + return &arena->nd_btt->dev; +} + +/* + * This function copies the desired (old/new) log entry into ent if + * it is not NULL. It returns the sub-slot number (0 or 1) + * where the desired log entry was found. Negative return values + * indicate errors. + */ +static int btt_log_read(struct arena_info *arena, u32 lane, + struct log_entry *ent, int old_flag) +{ + int ret; + int old_ent, ret_ent; + struct log_entry log[2]; + + ret = btt_log_read_pair(arena, lane, log); + if (ret) + return -EIO; + + old_ent = btt_log_get_old(log); + if (old_ent < 0 || old_ent > 1) { + dev_info(to_dev(arena), + "log corruption (%d): lane %d seq [%d, %d]\n", + old_ent, lane, log[0].seq, log[1].seq); + /* TODO set error state? */ + return -EIO; + } + + ret_ent = (old_flag ? old_ent : (1 - old_ent)); + + if (ent != NULL) + memcpy(ent, &log[ret_ent], LOG_ENT_SIZE); + + return ret_ent; +} + +/* + * This function commits a log entry to media + * It does _not_ prepare the freelist entry for the next write + * btt_flog_write is the wrapper for updating the freelist elements + */ +static int __btt_log_write(struct arena_info *arena, u32 lane, + u32 sub, struct log_entry *ent) +{ + int ret; + /* + * Ignore the padding in log_entry for calculating log_half. + * The entry is 'committed' when we write the sequence number, + * and we want to ensure that that is the last thing written. + * We don't bother writing the padding as that would be extra + * media wear and write amplification + */ + unsigned int log_half = (LOG_ENT_SIZE - 2 * sizeof(u64)) / 2; + u64 ns_off = arena->logoff + (((2 * lane) + sub) * LOG_ENT_SIZE); + void *src = ent; + + /* split the 16B write into atomic, durable halves */ + ret = arena_write_bytes(arena, ns_off, src, log_half); + if (ret) + return ret; + + ns_off += log_half; + src += log_half; + return arena_write_bytes(arena, ns_off, src, log_half); +} + +static int btt_flog_write(struct arena_info *arena, u32 lane, u32 sub, + struct log_entry *ent) +{ + int ret; + + ret = __btt_log_write(arena, lane, sub, ent); + if (ret) + return ret; + + /* prepare the next free entry */ + arena->freelist[lane].sub = 1 - arena->freelist[lane].sub; + if (++(arena->freelist[lane].seq) == 4) + arena->freelist[lane].seq = 1; + arena->freelist[lane].block = le32_to_cpu(ent->old_map); + + return ret; +} + +/* + * This function initializes the BTT map to the initial state, which is + * all-zeroes, and indicates an identity mapping + */ +static int btt_map_init(struct arena_info *arena) +{ + int ret = -EINVAL; + void *zerobuf; + size_t offset = 0; + size_t chunk_size = SZ_2M; + size_t mapsize = arena->logoff - arena->mapoff; + + zerobuf = kzalloc(chunk_size, GFP_KERNEL); + if (!zerobuf) + return -ENOMEM; + + while (mapsize) { + size_t size = min(mapsize, chunk_size); + + ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf, + size); + if (ret) + goto free; + + offset += size; + mapsize -= size; + cond_resched(); + } + + free: + kfree(zerobuf); + return ret; +} + +/* + * This function initializes the BTT log with 'fake' entries pointing + * to the initial reserved set of blocks as being free + */ +static int btt_log_init(struct arena_info *arena) +{ + int ret; + u32 i; + struct log_entry log, zerolog; + + memset(&zerolog, 0, sizeof(zerolog)); + + for (i = 0; i < arena->nfree; i++) { + log.lba = cpu_to_le32(i); + log.old_map = cpu_to_le32(arena->external_nlba + i); + log.new_map = cpu_to_le32(arena->external_nlba + i); + log.seq = cpu_to_le32(LOG_SEQ_INIT); + ret = __btt_log_write(arena, i, 0, &log); + if (ret) + return ret; + ret = __btt_log_write(arena, i, 1, &zerolog); + if (ret) + return ret; + } + + return 0; +} + +static int btt_freelist_init(struct arena_info *arena) +{ + int old, new, ret; + u32 i, map_entry; + struct log_entry log_new, log_old; + + arena->freelist = kcalloc(arena->nfree, sizeof(struct free_entry), + GFP_KERNEL); + if (!arena->freelist) + return -ENOMEM; + + for (i = 0; i < arena->nfree; i++) { + old = btt_log_read(arena, i, &log_old, LOG_OLD_ENT); + if (old < 0) + return old; + + new = btt_log_read(arena, i, &log_new, LOG_NEW_ENT); + if (new < 0) + return new; + + /* sub points to the next one to be overwritten */ + arena->freelist[i].sub = 1 - new; + arena->freelist[i].seq = nd_inc_seq(le32_to_cpu(log_new.seq)); + arena->freelist[i].block = le32_to_cpu(log_new.old_map); + + /* This implies a newly created or untouched flog entry */ + if (log_new.old_map == log_new.new_map) + continue; + + /* Check if map recovery is needed */ + ret = btt_map_read(arena, le32_to_cpu(log_new.lba), &map_entry, + NULL, NULL); + if (ret) + return ret; + if ((le32_to_cpu(log_new.new_map) != map_entry) && + (le32_to_cpu(log_new.old_map) == map_entry)) { + /* + * Last transaction wrote the flog, but wasn't able + * to complete the map write. So fix up the map. + */ + ret = btt_map_write(arena, le32_to_cpu(log_new.lba), + le32_to_cpu(log_new.new_map), 0, 0); + if (ret) + return ret; + } + + } + + return 0; +} + +static int btt_rtt_init(struct arena_info *arena) +{ + arena->rtt = kcalloc(arena->nfree, sizeof(u32), GFP_KERNEL); + if (arena->rtt == NULL) + return -ENOMEM; + + return 0; +} + +static int btt_maplocks_init(struct arena_info *arena) +{ + u32 i; + + arena->map_locks = kcalloc(arena->nfree, sizeof(struct aligned_lock), + GFP_KERNEL); + if (!arena->map_locks) + return -ENOMEM; + + for (i = 0; i < arena->nfree; i++) + spin_lock_init(&arena->map_locks[i].lock); + + return 0; +} + +static struct arena_info *alloc_arena(struct btt *btt, size_t size, + size_t start, size_t arena_off) +{ + struct arena_info *arena; + u64 logsize, mapsize, datasize; + u64 available = size; + + arena = kzalloc(sizeof(struct arena_info), GFP_KERNEL); + if (!arena) + return NULL; + arena->nd_btt = btt->nd_btt; + + if (!size) + return arena; + + arena->size = size; + arena->external_lba_start = start; + arena->external_lbasize = btt->lbasize; + arena->internal_lbasize = roundup(arena->external_lbasize, + INT_LBASIZE_ALIGNMENT); + arena->nfree = BTT_DEFAULT_NFREE; + arena->version_major = 1; + arena->version_minor = 1; + + if (available % BTT_PG_SIZE) + available -= (available % BTT_PG_SIZE); + + /* Two pages are reserved for the super block and its copy */ + available -= 2 * BTT_PG_SIZE; + + /* The log takes a fixed amount of space based on nfree */ + logsize = roundup(2 * arena->nfree * sizeof(struct log_entry), + BTT_PG_SIZE); + available -= logsize; + + /* Calculate optimal split between map and data area */ + arena->internal_nlba = div_u64(available - BTT_PG_SIZE, + arena->internal_lbasize + MAP_ENT_SIZE); + arena->external_nlba = arena->internal_nlba - arena->nfree; + + mapsize = roundup((arena->external_nlba * MAP_ENT_SIZE), BTT_PG_SIZE); + datasize = available - mapsize; + + /* 'Absolute' values, relative to start of storage space */ + arena->infooff = arena_off; + arena->dataoff = arena->infooff + BTT_PG_SIZE; + arena->mapoff = arena->dataoff + datasize; + arena->logoff = arena->mapoff + mapsize; + arena->info2off = arena->logoff + logsize; + return arena; +} + +static void free_arenas(struct btt *btt) +{ + struct arena_info *arena, *next; + + list_for_each_entry_safe(arena, next, &btt->arena_list, list) { + list_del(&arena->list); + kfree(arena->rtt); + kfree(arena->map_locks); + kfree(arena->freelist); + debugfs_remove_recursive(arena->debugfs_dir); + kfree(arena); + } +} + +/* + * This function checks if the metadata layout is valid and error free + */ +static int arena_is_valid(struct arena_info *arena, struct btt_sb *super, + u8 *uuid, u32 lbasize) +{ + u64 checksum; + + if (memcmp(super->uuid, uuid, 16)) + return 0; + + checksum = le64_to_cpu(super->checksum); + super->checksum = 0; + if (checksum != nd_btt_sb_checksum(super)) + return 0; + super->checksum = cpu_to_le64(checksum); + + if (lbasize != le32_to_cpu(super->external_lbasize)) + return 0; + + /* TODO: figure out action for this */ + if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0) + dev_info(to_dev(arena), "Found arena with an error flag\n"); + + return 1; +} + +/* + * This function reads an existing valid btt superblock and + * populates the corresponding arena_info struct + */ +static void parse_arena_meta(struct arena_info *arena, struct btt_sb *super, + u64 arena_off) +{ + arena->internal_nlba = le32_to_cpu(super->internal_nlba); + arena->internal_lbasize = le32_to_cpu(super->internal_lbasize); + arena->external_nlba = le32_to_cpu(super->external_nlba); + arena->external_lbasize = le32_to_cpu(super->external_lbasize); + arena->nfree = le32_to_cpu(super->nfree); + arena->version_major = le16_to_cpu(super->version_major); + arena->version_minor = le16_to_cpu(super->version_minor); + + arena->nextoff = (super->nextoff == 0) ? 0 : (arena_off + + le64_to_cpu(super->nextoff)); + arena->infooff = arena_off; + arena->dataoff = arena_off + le64_to_cpu(super->dataoff); + arena->mapoff = arena_off + le64_to_cpu(super->mapoff); + arena->logoff = arena_off + le64_to_cpu(super->logoff); + arena->info2off = arena_off + le64_to_cpu(super->info2off); + + arena->size = (super->nextoff > 0) ? (le64_to_cpu(super->nextoff)) : + (arena->info2off - arena->infooff + BTT_PG_SIZE); + + arena->flags = le32_to_cpu(super->flags); +} + +static int discover_arenas(struct btt *btt) +{ + int ret = 0; + struct arena_info *arena; + struct btt_sb *super; + size_t remaining = btt->rawsize; + u64 cur_nlba = 0; + size_t cur_off = 0; + int num_arenas = 0; + + super = kzalloc(sizeof(*super), GFP_KERNEL); + if (!super) + return -ENOMEM; + + while (remaining) { + /* Alloc memory for arena */ + arena = alloc_arena(btt, 0, 0, 0); + if (!arena) { + ret = -ENOMEM; + goto out_super; + } + + arena->infooff = cur_off; + ret = btt_info_read(arena, super); + if (ret) + goto out; + + if (!arena_is_valid(arena, super, btt->nd_btt->uuid, + btt->lbasize)) { + if (remaining == btt->rawsize) { + btt->init_state = INIT_NOTFOUND; + dev_info(to_dev(arena), "No existing arenas\n"); + goto out; + } else { + dev_info(to_dev(arena), + "Found corrupted metadata!\n"); + ret = -ENODEV; + goto out; + } + } + + arena->external_lba_start = cur_nlba; + parse_arena_meta(arena, super, cur_off); + + ret = btt_freelist_init(arena); + if (ret) + goto out; + + ret = btt_rtt_init(arena); + if (ret) + goto out; + + ret = btt_maplocks_init(arena); + if (ret) + goto out; + + list_add_tail(&arena->list, &btt->arena_list); + + remaining -= arena->size; + cur_off += arena->size; + cur_nlba += arena->external_nlba; + num_arenas++; + + if (arena->nextoff == 0) + break; + } + btt->num_arenas = num_arenas; + btt->nlba = cur_nlba; + btt->init_state = INIT_READY; + + kfree(super); + return ret; + + out: + kfree(arena); + free_arenas(btt); + out_super: + kfree(super); + return ret; +} + +static int create_arenas(struct btt *btt) +{ + size_t remaining = btt->rawsize; + size_t cur_off = 0; + + while (remaining) { + struct arena_info *arena; + size_t arena_size = min_t(u64, ARENA_MAX_SIZE, remaining); + + remaining -= arena_size; + if (arena_size < ARENA_MIN_SIZE) + break; + + arena = alloc_arena(btt, arena_size, btt->nlba, cur_off); + if (!arena) { + free_arenas(btt); + return -ENOMEM; + } + btt->nlba += arena->external_nlba; + if (remaining >= ARENA_MIN_SIZE) + arena->nextoff = arena->size; + else + arena->nextoff = 0; + cur_off += arena_size; + list_add_tail(&arena->list, &btt->arena_list); + } + + return 0; +} + +/* + * This function completes arena initialization by writing + * all the metadata. + * It is only called for an uninitialized arena when a write + * to that arena occurs for the first time. + */ +static int btt_arena_write_layout(struct arena_info *arena, u8 *uuid) +{ + int ret; + struct btt_sb *super; + + ret = btt_map_init(arena); + if (ret) + return ret; + + ret = btt_log_init(arena); + if (ret) + return ret; + + super = kzalloc(sizeof(struct btt_sb), GFP_NOIO); + if (!super) + return -ENOMEM; + + strncpy(super->signature, BTT_SIG, BTT_SIG_LEN); + memcpy(super->uuid, uuid, 16); + super->flags = cpu_to_le32(arena->flags); + super->version_major = cpu_to_le16(arena->version_major); + super->version_minor = cpu_to_le16(arena->version_minor); + super->external_lbasize = cpu_to_le32(arena->external_lbasize); + super->external_nlba = cpu_to_le32(arena->external_nlba); + super->internal_lbasize = cpu_to_le32(arena->internal_lbasize); + super->internal_nlba = cpu_to_le32(arena->internal_nlba); + super->nfree = cpu_to_le32(arena->nfree); + super->infosize = cpu_to_le32(sizeof(struct btt_sb)); + super->nextoff = cpu_to_le64(arena->nextoff); + /* + * Subtract arena->infooff (arena start) so numbers are relative + * to 'this' arena + */ + super->dataoff = cpu_to_le64(arena->dataoff - arena->infooff); + super->mapoff = cpu_to_le64(arena->mapoff - arena->infooff); + super->logoff = cpu_to_le64(arena->logoff - arena->infooff); + super->info2off = cpu_to_le64(arena->info2off - arena->infooff); + + super->flags = 0; + super->checksum = cpu_to_le64(nd_btt_sb_checksum(super)); + + ret = btt_info_write(arena, super); + + kfree(super); + return ret; +} + +/* + * This function completes the initialization for the BTT namespace + * such that it is ready to accept IOs + */ +static int btt_meta_init(struct btt *btt) +{ + int ret = 0; + struct arena_info *arena; + + mutex_lock(&btt->init_lock); + list_for_each_entry(arena, &btt->arena_list, list) { + ret = btt_arena_write_layout(arena, btt->nd_btt->uuid); + if (ret) + goto unlock; + + ret = btt_freelist_init(arena); + if (ret) + goto unlock; + + ret = btt_rtt_init(arena); + if (ret) + goto unlock; + + ret = btt_maplocks_init(arena); + if (ret) + goto unlock; + } + + btt->init_state = INIT_READY; + + unlock: + mutex_unlock(&btt->init_lock); + return ret; +} + +static u32 btt_meta_size(struct btt *btt) +{ + return btt->lbasize - btt->sector_size; +} + +/* + * This function calculates the arena in which the given LBA lies + * by doing a linear walk. This is acceptable since we expect only + * a few arenas. If we have backing devices that get much larger, + * we can construct a balanced binary tree of arenas at init time + * so that this range search becomes faster. + */ +static int lba_to_arena(struct btt *btt, sector_t sector, __u32 *premap, + struct arena_info **arena) +{ + struct arena_info *arena_list; + __u64 lba = div_u64(sector << SECTOR_SHIFT, btt->sector_size); + + list_for_each_entry(arena_list, &btt->arena_list, list) { + if (lba < arena_list->external_nlba) { + *arena = arena_list; + *premap = lba; + return 0; + } + lba -= arena_list->external_nlba; + } + + return -EIO; +} + +/* + * The following (lock_map, unlock_map) are mostly just to improve + * readability, since they index into an array of locks + */ +static void lock_map(struct arena_info *arena, u32 premap) + __acquires(&arena->map_locks[idx].lock) +{ + u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree; + + spin_lock(&arena->map_locks[idx].lock); +} + +static void unlock_map(struct arena_info *arena, u32 premap) + __releases(&arena->map_locks[idx].lock) +{ + u32 idx = (premap * MAP_ENT_SIZE / L1_CACHE_BYTES) % arena->nfree; + + spin_unlock(&arena->map_locks[idx].lock); +} + +static u64 to_namespace_offset(struct arena_info *arena, u64 lba) +{ + return arena->dataoff + ((u64)lba * arena->internal_lbasize); +} + +static int btt_data_read(struct arena_info *arena, struct page *page, + unsigned int off, u32 lba, u32 len) +{ + int ret; + u64 nsoff = to_namespace_offset(arena, lba); + void *mem = kmap_atomic(page); + + ret = arena_read_bytes(arena, nsoff, mem + off, len); + kunmap_atomic(mem); + + return ret; +} + +static int btt_data_write(struct arena_info *arena, u32 lba, + struct page *page, unsigned int off, u32 len) +{ + int ret; + u64 nsoff = to_namespace_offset(arena, lba); + void *mem = kmap_atomic(page); + + ret = arena_write_bytes(arena, nsoff, mem + off, len); + kunmap_atomic(mem); + + return ret; +} + +static void zero_fill_data(struct page *page, unsigned int off, u32 len) +{ + void *mem = kmap_atomic(page); + + memset(mem + off, 0, len); + kunmap_atomic(mem); +} + +#ifdef CONFIG_BLK_DEV_INTEGRITY +static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip, + struct arena_info *arena, u32 postmap, int rw) +{ + unsigned int len = btt_meta_size(btt); + u64 meta_nsoff; + int ret = 0; + + if (bip == NULL) + return 0; + + meta_nsoff = to_namespace_offset(arena, postmap) + btt->sector_size; + + while (len) { + unsigned int cur_len; + struct bio_vec bv; + void *mem; + + bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter); + /* + * The 'bv' obtained from bvec_iter_bvec has its .bv_len and + * .bv_offset already adjusted for iter->bi_bvec_done, and we + * can use those directly + */ + + cur_len = min(len, bv.bv_len); + mem = kmap_atomic(bv.bv_page); + if (rw) + ret = arena_write_bytes(arena, meta_nsoff, + mem + bv.bv_offset, cur_len); + else + ret = arena_read_bytes(arena, meta_nsoff, + mem + bv.bv_offset, cur_len); + + kunmap_atomic(mem); + if (ret) + return ret; + + len -= cur_len; + meta_nsoff += cur_len; + bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len); + } + + return ret; +} + +#else /* CONFIG_BLK_DEV_INTEGRITY */ +static int btt_rw_integrity(struct btt *btt, struct bio_integrity_payload *bip, + struct arena_info *arena, u32 postmap, int rw) +{ + return 0; +} +#endif + +static int btt_read_pg(struct btt *btt, struct bio_integrity_payload *bip, + struct page *page, unsigned int off, sector_t sector, + unsigned int len) +{ + int ret = 0; + int t_flag, e_flag; + struct arena_info *arena = NULL; + u32 lane = 0, premap, postmap; + + while (len) { + u32 cur_len; + + lane = nd_region_acquire_lane(btt->nd_region); + + ret = lba_to_arena(btt, sector, &premap, &arena); + if (ret) + goto out_lane; + + cur_len = min(btt->sector_size, len); + + ret = btt_map_read(arena, premap, &postmap, &t_flag, &e_flag); + if (ret) + goto out_lane; + + /* + * We loop to make sure that the post map LBA didn't change + * from under us between writing the RTT and doing the actual + * read. + */ + while (1) { + u32 new_map; + + if (t_flag) { + zero_fill_data(page, off, cur_len); + goto out_lane; + } + + if (e_flag) { + ret = -EIO; + goto out_lane; + } + + arena->rtt[lane] = RTT_VALID | postmap; + /* + * Barrier to make sure this write is not reordered + * to do the verification map_read before the RTT store + */ + barrier(); + + ret = btt_map_read(arena, premap, &new_map, &t_flag, + &e_flag); + if (ret) + goto out_rtt; + + if (postmap == new_map) + break; + + postmap = new_map; + } + + ret = btt_data_read(arena, page, off, postmap, cur_len); + if (ret) + goto out_rtt; + + if (bip) { + ret = btt_rw_integrity(btt, bip, arena, postmap, READ); + if (ret) + goto out_rtt; + } + + arena->rtt[lane] = RTT_INVALID; + nd_region_release_lane(btt->nd_region, lane); + + len -= cur_len; + off += cur_len; + sector += btt->sector_size >> SECTOR_SHIFT; + } + + return 0; + + out_rtt: + arena->rtt[lane] = RTT_INVALID; + out_lane: + nd_region_release_lane(btt->nd_region, lane); + return ret; +} + +static int btt_write_pg(struct btt *btt, struct bio_integrity_payload *bip, + sector_t sector, struct page *page, unsigned int off, + unsigned int len) +{ + int ret = 0; + struct arena_info *arena = NULL; + u32 premap = 0, old_postmap, new_postmap, lane = 0, i; + struct log_entry log; + int sub; + + while (len) { + u32 cur_len; + + lane = nd_region_acquire_lane(btt->nd_region); + + ret = lba_to_arena(btt, sector, &premap, &arena); + if (ret) + goto out_lane; + cur_len = min(btt->sector_size, len); + + if ((arena->flags & IB_FLAG_ERROR_MASK) != 0) { + ret = -EIO; + goto out_lane; + } + + new_postmap = arena->freelist[lane].block; + + /* Wait if the new block is being read from */ + for (i = 0; i < arena->nfree; i++) + while (arena->rtt[i] == (RTT_VALID | new_postmap)) + cpu_relax(); + + + if (new_postmap >= arena->internal_nlba) { + ret = -EIO; + goto out_lane; + } + + ret = btt_data_write(arena, new_postmap, page, off, cur_len); + if (ret) + goto out_lane; + + if (bip) { + ret = btt_rw_integrity(btt, bip, arena, new_postmap, + WRITE); + if (ret) + goto out_lane; + } + + lock_map(arena, premap); + ret = btt_map_read(arena, premap, &old_postmap, NULL, NULL); + if (ret) + goto out_map; + if (old_postmap >= arena->internal_nlba) { + ret = -EIO; + goto out_map; + } + + log.lba = cpu_to_le32(premap); + log.old_map = cpu_to_le32(old_postmap); + log.new_map = cpu_to_le32(new_postmap); + log.seq = cpu_to_le32(arena->freelist[lane].seq); + sub = arena->freelist[lane].sub; + ret = btt_flog_write(arena, lane, sub, &log); + if (ret) + goto out_map; + + ret = btt_map_write(arena, premap, new_postmap, 0, 0); + if (ret) + goto out_map; + + unlock_map(arena, premap); + nd_region_release_lane(btt->nd_region, lane); + + len -= cur_len; + off += cur_len; + sector += btt->sector_size >> SECTOR_SHIFT; + } + + return 0; + + out_map: + unlock_map(arena, premap); + out_lane: + nd_region_release_lane(btt->nd_region, lane); + return ret; +} + +static int btt_do_bvec(struct btt *btt, struct bio_integrity_payload *bip, + struct page *page, unsigned int len, unsigned int off, + int rw, sector_t sector) +{ + int ret; + + if (rw == READ) { + ret = btt_read_pg(btt, bip, page, off, sector, len); + flush_dcache_page(page); + } else { + flush_dcache_page(page); + ret = btt_write_pg(btt, bip, sector, page, off, len); + } + + return ret; +} + +static void btt_make_request(struct request_queue *q, struct bio *bio) +{ + struct bio_integrity_payload *bip = bio_integrity(bio); + struct btt *btt = q->queuedata; + struct bvec_iter iter; + unsigned long start; + struct bio_vec bvec; + int err = 0, rw; + bool do_acct; + + /* + * bio_integrity_enabled also checks if the bio already has an + * integrity payload attached. If it does, we *don't* do a + * bio_integrity_prep here - the payload has been generated by + * another kernel subsystem, and we just pass it through. + */ + if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { + err = -EIO; + goto out; + } + + do_acct = nd_iostat_start(bio, &start); + rw = bio_data_dir(bio); + bio_for_each_segment(bvec, bio, iter) { + unsigned int len = bvec.bv_len; + + BUG_ON(len > PAGE_SIZE); + /* Make sure len is in multiples of sector size. */ + /* XXX is this right? */ + BUG_ON(len < btt->sector_size); + BUG_ON(len % btt->sector_size); + + err = btt_do_bvec(btt, bip, bvec.bv_page, len, bvec.bv_offset, + rw, iter.bi_sector); + if (err) { + dev_info(&btt->nd_btt->dev, + "io error in %s sector %lld, len %d,\n", + (rw == READ) ? "READ" : "WRITE", + (unsigned long long) iter.bi_sector, len); + break; + } + } + if (do_acct) + nd_iostat_end(bio, start); + +out: + bio_endio(bio, err); +} + +static int btt_rw_page(struct block_device *bdev, sector_t sector, + struct page *page, int rw) +{ + struct btt *btt = bdev->bd_disk->private_data; + + btt_do_bvec(btt, NULL, page, PAGE_CACHE_SIZE, 0, rw, sector); + page_endio(page, rw & WRITE, 0); + return 0; +} + + +static int btt_getgeo(struct block_device *bd, struct hd_geometry *geo) +{ + /* some standard values */ + geo->heads = 1 << 6; + geo->sectors = 1 << 5; + geo->cylinders = get_capacity(bd->bd_disk) >> 11; + return 0; +} + +static const struct block_device_operations btt_fops = { + .owner = THIS_MODULE, + .rw_page = btt_rw_page, + .getgeo = btt_getgeo, + .revalidate_disk = nvdimm_revalidate_disk, +}; + +static int btt_blk_init(struct btt *btt) +{ + struct nd_btt *nd_btt = btt->nd_btt; + struct nd_namespace_common *ndns = nd_btt->ndns; + + /* create a new disk and request queue for btt */ + btt->btt_queue = blk_alloc_queue(GFP_KERNEL); + if (!btt->btt_queue) + return -ENOMEM; + + btt->btt_disk = alloc_disk(0); + if (!btt->btt_disk) { + blk_cleanup_queue(btt->btt_queue); + return -ENOMEM; + } + + nvdimm_namespace_disk_name(ndns, btt->btt_disk->disk_name); + btt->btt_disk->driverfs_dev = &btt->nd_btt->dev; + btt->btt_disk->major = btt_major; + btt->btt_disk->first_minor = 0; + btt->btt_disk->fops = &btt_fops; + btt->btt_disk->private_data = btt; + btt->btt_disk->queue = btt->btt_queue; + btt->btt_disk->flags = GENHD_FL_EXT_DEVT; + + blk_queue_make_request(btt->btt_queue, btt_make_request); + blk_queue_logical_block_size(btt->btt_queue, btt->sector_size); + blk_queue_max_hw_sectors(btt->btt_queue, UINT_MAX); + blk_queue_bounce_limit(btt->btt_queue, BLK_BOUNCE_ANY); + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, btt->btt_queue); + btt->btt_queue->queuedata = btt; + + set_capacity(btt->btt_disk, 0); + add_disk(btt->btt_disk); + if (btt_meta_size(btt)) { + int rc = nd_integrity_init(btt->btt_disk, btt_meta_size(btt)); + + if (rc) { + del_gendisk(btt->btt_disk); + put_disk(btt->btt_disk); + blk_cleanup_queue(btt->btt_queue); + return rc; + } + } + set_capacity(btt->btt_disk, btt->nlba * btt->sector_size >> 9); + revalidate_disk(btt->btt_disk); + + return 0; +} + +static void btt_blk_cleanup(struct btt *btt) +{ + blk_integrity_unregister(btt->btt_disk); + del_gendisk(btt->btt_disk); + put_disk(btt->btt_disk); + blk_cleanup_queue(btt->btt_queue); +} + +/** + * btt_init - initialize a block translation table for the given device + * @nd_btt: device with BTT geometry and backing device info + * @rawsize: raw size in bytes of the backing device + * @lbasize: lba size of the backing device + * @uuid: A uuid for the backing device - this is stored on media + * @maxlane: maximum number of parallel requests the device can handle + * + * Initialize a Block Translation Table on a backing device to provide + * single sector power fail atomicity. + * + * Context: + * Might sleep. + * + * Returns: + * Pointer to a new struct btt on success, NULL on failure. + */ +static struct btt *btt_init(struct nd_btt *nd_btt, unsigned long long rawsize, + u32 lbasize, u8 *uuid, struct nd_region *nd_region) +{ + int ret; + struct btt *btt; + struct device *dev = &nd_btt->dev; + + btt = kzalloc(sizeof(struct btt), GFP_KERNEL); + if (!btt) + return NULL; + + btt->nd_btt = nd_btt; + btt->rawsize = rawsize; + btt->lbasize = lbasize; + btt->sector_size = ((lbasize >= 4096) ? 4096 : 512); + INIT_LIST_HEAD(&btt->arena_list); + mutex_init(&btt->init_lock); + btt->nd_region = nd_region; + + ret = discover_arenas(btt); + if (ret) { + dev_err(dev, "init: error in arena_discover: %d\n", ret); + goto out_free; + } + + if (btt->init_state != INIT_READY && nd_region->ro) { + dev_info(dev, "%s is read-only, unable to init btt metadata\n", + dev_name(&nd_region->dev)); + goto out_free; + } else if (btt->init_state != INIT_READY) { + btt->num_arenas = (rawsize / ARENA_MAX_SIZE) + + ((rawsize % ARENA_MAX_SIZE) ? 1 : 0); + dev_dbg(dev, "init: %d arenas for %llu rawsize\n", + btt->num_arenas, rawsize); + + ret = create_arenas(btt); + if (ret) { + dev_info(dev, "init: create_arenas: %d\n", ret); + goto out_free; + } + + ret = btt_meta_init(btt); + if (ret) { + dev_err(dev, "init: error in meta_init: %d\n", ret); + goto out_free; + } + } + + ret = btt_blk_init(btt); + if (ret) { + dev_err(dev, "init: error in blk_init: %d\n", ret); + goto out_free; + } + + btt_debugfs_init(btt); + + return btt; + + out_free: + kfree(btt); + return NULL; +} + +/** + * btt_fini - de-initialize a BTT + * @btt: the BTT handle that was generated by btt_init + * + * De-initialize a Block Translation Table on device removal + * + * Context: + * Might sleep. + */ +static void btt_fini(struct btt *btt) +{ + if (btt) { + btt_blk_cleanup(btt); + free_arenas(btt); + debugfs_remove_recursive(btt->debugfs_dir); + kfree(btt); + } +} + +int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns) +{ + struct nd_btt *nd_btt = to_nd_btt(ndns->claim); + struct nd_region *nd_region; + struct btt *btt; + size_t rawsize; + + if (!nd_btt->uuid || !nd_btt->ndns || !nd_btt->lbasize) + return -ENODEV; + + rawsize = nvdimm_namespace_capacity(ndns) - SZ_4K; + if (rawsize < ARENA_MIN_SIZE) { + return -ENXIO; + } + nd_region = to_nd_region(nd_btt->dev.parent); + btt = btt_init(nd_btt, rawsize, nd_btt->lbasize, nd_btt->uuid, + nd_region); + if (!btt) + return -ENOMEM; + nd_btt->btt = btt; + + return 0; +} +EXPORT_SYMBOL(nvdimm_namespace_attach_btt); + +int nvdimm_namespace_detach_btt(struct nd_namespace_common *ndns) +{ + struct nd_btt *nd_btt = to_nd_btt(ndns->claim); + struct btt *btt = nd_btt->btt; + + btt_fini(btt); + nd_btt->btt = NULL; + + return 0; +} +EXPORT_SYMBOL(nvdimm_namespace_detach_btt); + +static int __init nd_btt_init(void) +{ + int rc; + + BUILD_BUG_ON(sizeof(struct btt_sb) != SZ_4K); + + btt_major = register_blkdev(0, "btt"); + if (btt_major < 0) + return btt_major; + + debugfs_root = debugfs_create_dir("btt", NULL); + if (IS_ERR_OR_NULL(debugfs_root)) { + rc = -ENXIO; + goto err_debugfs; + } + + return 0; + + err_debugfs: + unregister_blkdev(btt_major, "btt"); + + return rc; +} + +static void __exit nd_btt_exit(void) +{ + debugfs_remove_recursive(debugfs_root); + unregister_blkdev(btt_major, "btt"); +} + +MODULE_ALIAS_ND_DEVICE(ND_DEVICE_BTT); +MODULE_AUTHOR("Vishal Verma <vishal.l.verma@linux.intel.com>"); +MODULE_LICENSE("GPL v2"); +module_init(nd_btt_init); +module_exit(nd_btt_exit); |