--- /dev/null
+/*
+ * 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 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 = (le64_to_cpu(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 (!nd_btt_arena_is_valid(btt->nd_btt, super)) {
+ 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)
+{
+ int ret;
+ u64 sum;
+ struct btt_sb *super;
+ struct nd_btt *nd_btt = arena->nd_btt;
+ const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
+
+ 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, nd_btt->uuid, 16);
+ memcpy(super->parent_uuid, parent_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;
+ sum = nd_sb_checksum((struct nd_gen_sb *) super);
+ super->checksum = cpu_to_le64(sum);
+
+ 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);
+ 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 blk_qc_t 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)) {
+ bio->bi_error = -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);
+ bio->bi_error = err;
+ break;
+ }
+ }
+ if (do_acct)
+ nd_iostat_end(bio, start);
+
+out:
+ bio_endio(bio);
+ return BLK_QC_T_NONE;
+}
+
+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)
+{
+ 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;
+
+ 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);
Code Review / kvmfornfv.git / blobdiff