// SPDX-License-Identifier: GPL-2.0-only
#include "dm.h"
#include "persistent-data/dm-transaction-manager.h"
#include "persistent-data/dm-bitset.h"
#include "persistent-data/dm-space-map.h"
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#define DM_MSG_PREFIX "era"
#define SUPERBLOCK_LOCATION 0
#define SUPERBLOCK_MAGIC 2126579579
#define SUPERBLOCK_CSUM_XOR 146538381
#define MIN_ERA_VERSION 1
#define MAX_ERA_VERSION 1
#define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION
#define MIN_BLOCK_SIZE 8
/*
*--------------------------------------------------------------
* Writeset
*--------------------------------------------------------------
*/
struct writeset_metadata {
uint32_t nr_bits;
dm_block_t root;
};
struct writeset {
struct writeset_metadata md;
/*
* An in core copy of the bits to save constantly doing look ups on
* disk.
*/
unsigned long *bits;
};
/*
* This does not free off the on disk bitset as this will normally be done
* after digesting into the era array.
*/
static void writeset_free(struct writeset *ws)
{
vfree(ws->bits);
ws->bits = NULL;
}
static int setup_on_disk_bitset(struct dm_disk_bitset *info,
unsigned int nr_bits, dm_block_t *root)
{
int r;
r = dm_bitset_empty(info, root);
if (r)
return r;
return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
}
static size_t bitset_size(unsigned int nr_bits)
{
return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
}
/*
* Allocates memory for the in core bitset.
*/
static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
{
ws->bits = vzalloc(bitset_size(nr_blocks));
if (!ws->bits) {
DMERR("%s: couldn't allocate in memory bitset", __func__);
return -ENOMEM;
}
return 0;
}
/*
* Wipes the in-core bitset, and creates a new on disk bitset.
*/
static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws,
dm_block_t nr_blocks)
{
int r;
memset(ws->bits, 0, bitset_size(nr_blocks));
ws->md.nr_bits = nr_blocks;
r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
if (r) {
DMERR("%s: setup_on_disk_bitset failed", __func__);
return r;
}
return 0;
}
static bool writeset_marked(struct writeset *ws, dm_block_t block)
{
return test_bit(block, ws->bits);
}
static int writeset_marked_on_disk(struct dm_disk_bitset *info,
struct writeset_metadata *m, dm_block_t block,
bool *result)
{
int r;
dm_block_t old = m->root;
/*
* The bitset was flushed when it was archived, so we know there'll
* be no change to the root.
*/
r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
if (r) {
DMERR("%s: dm_bitset_test_bit failed", __func__);
return r;
}
BUG_ON(m->root != old);
return r;
}
/*
* Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
*/
static int writeset_test_and_set(struct dm_disk_bitset *info,
struct writeset *ws, uint32_t block)
{
int r;
if (!test_bit(block, ws->bits)) {
r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
if (r) {
/* FIXME: fail mode */
return r;
}
return 0;
}
return 1;
}
/*
*--------------------------------------------------------------
* On disk metadata layout
*--------------------------------------------------------------
*/
#define SPACE_MAP_ROOT_SIZE 128
#define UUID_LEN 16
struct writeset_disk {
__le32 nr_bits;
__le64 root;
} __packed;
struct superblock_disk {
__le32 csum;
__le32 flags;
__le64 blocknr;
__u8 uuid[UUID_LEN];
__le64 magic;
__le32 version;
__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
__le32 data_block_size;
__le32 metadata_block_size;
__le32 nr_blocks;
__le32 current_era;
struct writeset_disk current_writeset;
/*
* Only these two fields are valid within the metadata snapshot.
*/
__le64 writeset_tree_root;
__le64 era_array_root;
__le64 metadata_snap;
} __packed;
/*
*--------------------------------------------------------------
* Superblock validation
*--------------------------------------------------------------
*/
static void sb_prepare_for_write(const struct dm_block_validator *v,
struct dm_block *b,
size_t sb_block_size)
{
struct superblock_disk *disk = dm_block_data(b);
disk->blocknr = cpu_to_le64(dm_block_location(b));
disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
sb_block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
}
static int check_metadata_version(struct superblock_disk *disk)
{
uint32_t metadata_version = le32_to_cpu(disk->version);
if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
return -EINVAL;
}
return 0;
}
static int sb_check(const struct dm_block_validator *v,
struct dm_block *b,
size_t sb_block_size)
{
struct superblock_disk *disk = dm_block_data(b);
__le32 csum_le;
if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
DMERR("%s failed: blocknr %llu: wanted %llu",
__func__, le64_to_cpu(disk->blocknr),
(unsigned long long)dm_block_location(b));
return -ENOTBLK;
}
if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
DMERR("%s failed: magic %llu: wanted %llu",
__func__, le64_to_cpu(disk->magic),
(unsigned long long) SUPERBLOCK_MAGIC);
return -EILSEQ;
}
csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
sb_block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR));
if (csum_le != disk->csum) {
DMERR("%s failed: csum %u: wanted %u",
__func__, le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
return -EILSEQ;
}
return check_metadata_version(disk);
}
static const struct dm_block_validator sb_validator = {
.name = "superblock",
.prepare_for_write = sb_prepare_for_write,
.check = sb_check
};
/*
*--------------------------------------------------------------
* Low level metadata handling
*--------------------------------------------------------------
*/
#define DM_ERA_METADATA_BLOCK_SIZE 4096
#define ERA_MAX_CONCURRENT_LOCKS 5
struct era_metadata {
struct block_device *bdev;
struct dm_block_manager *bm;
struct dm_space_map *sm;
struct dm_transaction_manager *tm;
dm_block_t block_size;
uint32_t nr_blocks;
uint32_t current_era;
/*
* We preallocate 2 writesets. When an era rolls over we
* switch between them. This means the allocation is done at
* preresume time, rather than on the io path.
*/
struct writeset writesets[2];
struct writeset *current_writeset;
dm_block_t writeset_tree_root;
dm_block_t era_array_root;
struct dm_disk_bitset bitset_info;
struct dm_btree_info writeset_tree_info;
struct dm_array_info era_array_info;
dm_block_t metadata_snap;
/*
* A flag that is set whenever a writeset has been archived.
*/
bool archived_writesets;
/*
* Reading the space map root can fail, so we read it into this
* buffer before the superblock is locked and updated.
*/
__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
static int superblock_read_lock(struct era_metadata *md,
struct dm_block **sblock)
{
return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
&sb_validator, sblock);
}
static int superblock_lock_zero(struct era_metadata *md,
struct dm_block **sblock)
{
return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
&sb_validator, sblock);
}
static int superblock_lock(struct era_metadata *md,
struct dm_block **sblock)
{
return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
&sb_validator, sblock);
}
/* FIXME: duplication with cache and thin */
static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
{
int r;
unsigned int i;
struct dm_block *b;
__le64 *data_le, zero = cpu_to_le64(0);
unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
/*
* We can't use a validator here - it may be all zeroes.
*/
r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
if (r)
return r;
data_le = dm_block_data(b);
*result = true;
for (i = 0; i < sb_block_size; i++) {
if (data_le[i] != zero) {
*result = false;
break;
}
}
dm_bm_unlock(b);
return 0;
}
/*----------------------------------------------------------------*/
static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
{
disk->nr_bits = cpu_to_le32(core->nr_bits);
disk->root = cpu_to_le64(core->root);
}
static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
{
core->nr_bits = le32_to_cpu(disk->nr_bits);
core->root = le64_to_cpu(disk->root);
}
static void ws_inc(void *context, const void *value, unsigned int count)
{
struct era_metadata *md = context;
struct writeset_disk ws_d;
dm_block_t b;
unsigned int i;
for (i = 0; i < count; i++) {
memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
b = le64_to_cpu(ws_d.root);
dm_tm_inc(md->tm, b);
}
}
static void ws_dec(void *context, const void *value, unsigned int count)
{
struct era_metadata *md = context;
struct writeset_disk ws_d;
dm_block_t b;
unsigned int i;
for (i = 0; i < count; i++) {
memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
b = le64_to_cpu(ws_d.root);
dm_bitset_del(&md->bitset_info, b);
}
}
static int ws_eq(void *context, const void *value1, const void *value2)
{
return !memcmp(value1, value2, sizeof(struct writeset_disk));
}
/*----------------------------------------------------------------*/
static void setup_writeset_tree_info(struct era_metadata *md)
{
struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
md->writeset_tree_info.tm = md->tm;
md->writeset_tree_info.levels = 1;
vt->context = md;
vt->size = sizeof(struct writeset_disk);
vt->inc = ws_inc;
vt->dec = ws_dec;
vt->equal = ws_eq;
}
static void setup_era_array_info(struct era_metadata *md)
{
struct dm_btree_value_type vt;
vt.context = NULL;
vt.size = sizeof(__le32);
vt.inc = NULL;
vt.dec = NULL;
vt.equal = NULL;
dm_array_info_init(&md->era_array_info, md->tm, &vt);
}
static void setup_infos(struct era_metadata *md)
{
dm_disk_bitset_init(md->tm, &md->bitset_info);
setup_writeset_tree_info(md);
setup_era_array_info(md);
}
/*----------------------------------------------------------------*/
static int create_fresh_metadata(struct era_metadata *md)
{
int r;
r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
&md->tm, &md->sm);
if (r < 0) {
DMERR("dm_tm_create_with_sm failed");
return r;
}
setup_infos(md);
r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
if (r) {
DMERR("couldn't create new writeset tree");
goto bad;
}
r = dm_array_empty(&md->era_array_info, &md->era_array_root);
if (r) {
DMERR("couldn't create era array");
goto bad;
}
return 0;
bad:
dm_sm_destroy(md->sm);
dm_tm_destroy(md->tm);
return r;
}
static int save_sm_root(struct era_metadata *md)
{
int r;
size_t metadata_len;
r = dm_sm_root_size(md->sm, &metadata_len);
if (r < 0)
return r;
return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
metadata_len);
}
static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
{
memcpy(&disk->metadata_space_map_root,
&md->metadata_space_map_root,
sizeof(md->metadata_space_map_root));
}
/*
* Writes a superblock, including the static fields that don't get updated
* with every commit (possible optimisation here). 'md' should be fully
* constructed when this is called.
*/
static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
{
disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
disk->flags = cpu_to_le32(0ul);
/* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
memset(disk->uuid, 0, sizeof(disk->uuid));
disk->version = cpu_to_le32(MAX_ERA_VERSION);
copy_sm_root(md, disk);
disk->data_block_size = cpu_to_le32(md->block_size);
disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
disk->nr_blocks = cpu_to_le32(md->nr_blocks);
disk->current_era = cpu_to_le32(md->current_era);
ws_pack(&md->current_writeset->md, &disk->current_writeset);
disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
disk->era_array_root = cpu_to_le64(md->era_array_root);
disk->metadata_snap = cpu_to_le64(md->metadata_snap);
}
static int write_superblock(struct era_metadata *md)
{
int r;
struct dm_block *sblock;
struct superblock_disk *disk;
r = save_sm_root(md);
if (r) {
DMERR("%s: save_sm_root failed", __func__);
return r;
}
r = superblock_lock_zero(md, &sblock);
if (r)
return r;
disk = dm_block_data(sblock);
prepare_superblock(md, disk);
return dm_tm_commit(md->tm, sblock);
}
/*
* Assumes block_size and the infos are set.
*/
static int format_metadata(struct era_metadata *md)
{
int r;
r = create_fresh_metadata(md);
if (r)
return r;
r = write_superblock(md);
if (r) {
dm_sm_destroy(md->sm);
dm_tm_destroy(md->tm);
return r;
}
return 0;
}
static int open_metadata(struct era_metadata *md)
{
int r;
struct dm_block *sblock;
struct superblock_disk *disk;
r = superblock_read_lock(md, &sblock);
if (r) {
DMERR("couldn't read_lock superblock");
return r;
}
disk = dm_block_data(sblock);
/* Verify the data block size hasn't changed */
if (le32_to_cpu(disk->data_block_size) != md->block_size) {
DMERR("changing the data block size (from %u to %llu) is not supported",
le32_to_cpu(disk->data_block_size), md->block_size);
r = -EINVAL;
goto bad;
}
r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
disk->metadata_space_map_root,
sizeof(disk->metadata_space_map_root),
&md->tm, &md->sm);
if (r) {
DMERR("dm_tm_open_with_sm failed");
goto bad;
}
setup_infos(md);
md->nr_blocks = le32_to_cpu(disk->nr_blocks);
md->current_era = le32_to_cpu(disk->current_era);
ws_unpack(&disk->current_writeset, &md->current_writeset->md);
md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
md->era_array_root = le64_to_cpu(disk->era_array_root);
md->metadata_snap = le64_to_cpu(disk->metadata_snap);
md->archived_writesets = true;
dm_bm_unlock(sblock);
return 0;
bad:
dm_bm_unlock(sblock);
return r;
}
static int open_or_format_metadata(struct era_metadata *md,
bool may_format)
{
int r;
bool unformatted = false;
r = superblock_all_zeroes(md->bm, &unformatted);
if (r)
return r;
if (unformatted)
return may_format ? format_metadata(md) : -EPERM;
return open_metadata(md);
}
static int create_persistent_data_objects(struct era_metadata *md,
bool may_format)
{
int r;
md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
ERA_MAX_CONCURRENT_LOCKS);
if (IS_ERR(md->bm)) {
DMERR("could not create block manager");
return PTR_ERR(md->bm);
}
r = open_or_format_metadata(md, may_format);
if (r)
dm_block_manager_destroy(md->bm);
return r;
}
static void destroy_persistent_data_objects(struct era_metadata *md)
{
dm_sm_destroy(md->sm);
dm_tm_destroy(md->tm);
dm_block_manager_destroy(md->bm);
}
/*
* This waits until all era_map threads have picked up the new filter.
*/
static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
{
rcu_assign_pointer(md->current_writeset, new_writeset);
synchronize_rcu();
}
/*
*------------------------------------------------------------------------
* Writesets get 'digested' into the main era array.
*
* We're using a coroutine here so the worker thread can do the digestion,
* thus avoiding synchronisation of the metadata. Digesting a whole
* writeset in one go would cause too much latency.
*------------------------------------------------------------------------
*/
struct digest {
uint32_t era;
unsigned int nr_bits, current_bit;
struct writeset_metadata writeset;
__le32 value;
struct dm_disk_bitset info;
int (*step)(struct era_metadata *md, struct digest *d);
};
static int metadata_digest_lookup_writeset(struct era_metadata *md,
struct digest *d);
static int metadata_digest_remove_writeset(struct era_metadata *md,
struct digest *d)
{
int r;
uint64_t key = d->era;
r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
&key, &md->writeset_tree_root);
if (r) {
DMERR("%s: dm_btree_remove failed", __func__);
return r;
}
d->step = metadata_digest_lookup_writeset;
return 0;
}
#define INSERTS_PER_STEP 100
static int metadata_digest_transcribe_writeset(struct era_metadata *md,
struct digest *d)
{
int r;
bool marked;
unsigned int b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
for (b = d->current_bit; b < e; b++) {
r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
if (r) {
DMERR("%s: writeset_marked_on_disk failed", __func__);
return r;
}
if (!marked)
continue;
__dm_bless_for_disk(&d->value);
r = dm_array_set_value(&md->era_array_info, md->era_array_root,
b, &d->value, &md->era_array_root);
if (r) {
DMERR("%s: dm_array_set_value failed", __func__);
return r;
}
}
if (b == d->nr_bits)
d->step = metadata_digest_remove_writeset;
else
d->current_bit = b;
return 0;
}
static int metadata_digest_lookup_writeset(struct era_metadata *md,
struct digest *d)
{
int r;
uint64_t key;
struct writeset_disk disk;
r = dm_btree_find_lowest_key(&md->writeset_tree_info,
md->writeset_tree_root, &key);
if (r < 0)
return r;
d->era = key;
r = dm_btree_lookup(&md->writeset_tree_info,
md->writeset_tree_root, &key, &disk);
if (r) {
if (r == -ENODATA) {
d->step = NULL;
return 0;
}
DMERR("%s: dm_btree_lookup failed", __func__);
return r;
}
ws_unpack(&disk, &d->writeset);
d->value = cpu_to_le32(key);
/*
* We initialise another bitset info to avoid any caching side effects
* with the previous one.
*/
dm_disk_bitset_init(md->tm, &d->info);
d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
d->current_bit = 0;
d->step = metadata_digest_transcribe_writeset;
return 0;
}
static int metadata_digest_start(struct era_metadata *md, struct digest *d)
{
if (d->step)
return 0;
memset(d, 0, sizeof(*d));
d->step = metadata_digest_lookup_writeset;
return 0;
}
/*
*-----------------------------------------------------------------
* High level metadata interface. Target methods should use these,
* and not the lower level ones.
*-----------------------------------------------------------------
*/
static struct era_metadata *metadata_open(struct block_device *bdev,
sector_t block_size,
bool may_format)
{
int r;
struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
if (!md)
return NULL;
md->bdev = bdev;
md->block_size = block_size;
md->writesets[0].md.root = INVALID_WRITESET_ROOT;
md->writesets[1].md.root = INVALID_WRITESET_ROOT;
md->current_writeset = &md->writesets[0];
r = create_persistent_data_objects(md, may_format);
if (r) {
kfree(md);
return ERR_PTR(r);
}
return md;
}
static void metadata_close(struct era_metadata *md)
{
writeset_free(&md->writesets[0]);
writeset_free(&md->writesets[1]);
destroy_persistent_data_objects(md);
kfree(md);
}
static bool valid_nr_blocks(dm_block_t n)
{
/*
* dm_bitset restricts us to 2^32. test_bit & co. restrict us
* further to 2^31 - 1
*/
return n < (1ull << 31);
}
static int metadata_resize(struct era_metadata *md, void *arg)
{
int r;
dm_block_t *new_size = arg;
__le32 value;
if (!valid_nr_blocks(*new_size)) {
DMERR("Invalid number of origin blocks %llu",
(unsigned long long) *new_size);
return -EINVAL;
}
writeset_free(&md->writesets[0]);
writeset_free(&md->writesets[1]);
r = writeset_alloc(&md->writesets[0], *new_size);
if (r) {
DMERR("%s: writeset_alloc failed for writeset 0", __func__);
return r;
}
r = writeset_alloc(&md->writesets[1], *new_size);
if (r) {
DMERR("%s: writeset_alloc failed for writeset 1", __func__);
writeset_free(&md->writesets[0]);
return r;
}
value = cpu_to_le32(0u);
__dm_bless_for_disk(&value);
r = dm_array_resize(&md->era_array_info, md->era_array_root,
md->nr_blocks, *new_size,
&value, &md->era_array_root);
if (r) {
DMERR("%s: dm_array_resize failed", __func__);
writeset_free(&md->writesets[0]);
writeset_free(&md->writesets[1]);
return r;
}
md->nr_blocks = *new_size;
return 0;
}
static int metadata_era_archive(struct era_metadata *md)
{
int r;
uint64_t keys[1];
struct writeset_disk value;
r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
&md->current_writeset->md.root);
if (r) {
DMERR("%s: dm_bitset_flush failed", __func__);
return r;
}
ws_pack(&md->current_writeset->md, &value);
keys[0] = md->current_era;
__dm_bless_for_disk(&value);
r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
keys, &value, &md->writeset_tree_root);
if (r) {
DMERR("%s: couldn't insert writeset into btree", __func__);
/* FIXME: fail mode */
return r;
}
md->current_writeset->md.root = INVALID_WRITESET_ROOT;
md->archived_writesets = true;
return 0;
}
static struct writeset *next_writeset(struct era_metadata *md)
{
return (md->current_writeset == &md->writesets[0]) ?
&md->writesets[1] : &md->writesets[0];
}
static int metadata_new_era(struct era_metadata *md)
{
int r;
struct writeset *new_writeset = next_writeset(md);
r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks);
if (r) {
DMERR("%s: writeset_init failed", __func__);
return r;
}
swap_writeset(md, new_writeset);
md->current_era++;
return 0;
}
static int metadata_era_rollover(struct era_metadata *md)
{
int r;
if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
r = metadata_era_archive(md);
if (r) {
DMERR("%s: metadata_archive_era failed", __func__);
/* FIXME: fail mode? */
return r;
}
}
r = metadata_new_era(md);
if (r) {
DMERR("%s: new era failed", __func__);
/* FIXME: fail mode */
return r;
}
return 0;
}
static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
{
bool r;
struct writeset *ws;
rcu_read_lock();
ws = rcu_dereference(md->current_writeset);
r = writeset_marked(ws, block);
rcu_read_unlock();
return r;
}
static int metadata_commit(struct era_metadata *md)
{
int r;
struct dm_block *sblock;
if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
&md->current_writeset->md.root);
if (r) {
DMERR("%s: bitset flush failed", __func__);
return r;
}
}
r = dm_tm_pre_commit(md->tm);
if (r) {
DMERR("%s: pre commit failed", __func__);
return r;
}
r = save_sm_root(md);
if (r) {
DMERR("%s: save_sm_root failed", __func__);
return r;
}
r = superblock_lock(md, &sblock);
if (r) {
DMERR("%s: superblock lock failed", __func__);
return r;
}
prepare_superblock(md, dm_block_data(sblock));
return dm_tm_commit(md->tm, sblock);
}
static int metadata_checkpoint(struct era_metadata *md)
{
/*
* For now we just rollover, but later I want to put a check in to
* avoid this if the filter is still pretty fresh.
*/
return metadata_era_rollover(md);
}
/*
* Metadata snapshots allow userland to access era data.
*/
static int metadata_take_snap(struct era_metadata *md)
{
int r, inc;
struct dm_block *clone;
if (md->metadata_snap != SUPERBLOCK_LOCATION) {
DMERR("%s: metadata snapshot already exists", __func__);
return -EINVAL;
}
r = metadata_era_rollover(md);
if (r) {
DMERR("%s: era rollover failed", __func__);
return r;
}
r = metadata_commit(md);
if (r) {
DMERR("%s: pre commit failed", __func__);
return r;
}
r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
if (r) {
DMERR("%s: couldn't increment superblock", __func__);
return r;
}
r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
&sb_validator, &clone, &inc);
if (r) {
DMERR("%s: couldn't shadow superblock", __func__);
dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
return r;
}
BUG_ON(!inc);
r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
if (r) {
DMERR("%s: couldn't inc writeset tree root", __func__);
dm_tm_unlock(md->tm, clone);
return r;
}
r = dm_sm_inc_block(md->sm, md->era_array_root);
if (r) {
DMERR("%s: couldn't inc era tree root", __func__);
dm_sm_dec_block(md->sm, md->writeset_tree_root);
dm_tm_unlock(md->tm, clone);
return r;
}
md->metadata_snap = dm_block_location(clone);
dm_tm_unlock(md->tm, clone);
return 0;
}
static int metadata_drop_snap(struct era_metadata *md)
{
int r;
dm_block_t location;
struct dm_block *clone;
struct superblock_disk *disk;
if (md->metadata_snap == SUPERBLOCK_LOCATION) {
DMERR("%s: no snap to drop", __func__);
return -EINVAL;
}
r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
if (r) {
DMERR("%s: couldn't read lock superblock clone", __func__);
return r;
}
/*
* Whatever happens now we'll commit with no record of the metadata
* snap.
*/
md->metadata_snap = SUPERBLOCK_LOCATION;
disk = dm_block_data(clone);
r = dm_btree_del(&md->writeset_tree_info,
le64_to_cpu(disk->writeset_tree_root));
if (r) {
DMERR("%s: error deleting writeset tree clone", __func__);
dm_tm_unlock(md->tm, clone);
return r;
}
r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
if (r) {
DMERR("%s: error deleting era array clone", __func__);
dm_tm_unlock(md->tm, clone);
return r;
}
location = dm_block_location(clone);
dm_tm_unlock(md->tm, clone);
return dm_sm_dec_block(md->sm, location);
}
struct metadata_stats {
dm_block_t used;
dm_block_t total;
dm_block_t snap;
uint32_t era;
};
static int metadata_get_stats(struct era_metadata *md, void *ptr)
{
int r;
struct metadata_stats *s = ptr;
dm_block_t nr_free, nr_total;
r = dm_sm_get_nr_free(md->sm, &nr_free);
if (r) {
DMERR("dm_sm_get_nr_free returned %d", r);
return r;
}
r = dm_sm_get_nr_blocks(md->sm, &nr_total);
if (r) {
DMERR("dm_pool_get_metadata_dev_size returned %d", r);
return r;
}
s->used = nr_total - nr_free;
s->total = nr_total;
s->snap = md->metadata_snap;
s->era = md->current_era;
return 0;
}
/*----------------------------------------------------------------*/
struct era {
struct dm_target *ti;
struct dm_dev *metadata_dev;
struct dm_dev *origin_dev;
dm_block_t nr_blocks;
uint32_t sectors_per_block;
int sectors_per_block_shift;
struct era_metadata *md;
struct workqueue_struct *wq;
struct work_struct worker;
spinlock_t deferred_lock;
struct bio_list deferred_bios;
spinlock_t rpc_lock;
struct list_head rpc_calls;
struct digest digest;
atomic_t suspended;
};
struct rpc {
struct list_head list;
int (*fn0)(struct era_metadata *md);
int (*fn1)(struct era_metadata *md, void *ref);
void *arg;
int result;
struct completion complete;
};
/*
*---------------------------------------------------------------
* Remapping.
*---------------------------------------------------------------
*/
static bool block_size_is_power_of_two(struct era *era)
{
return era->sectors_per_block_shift >= 0;
}
static dm_block_t get_block(struct era *era, struct bio *bio)
{
sector_t block_nr = bio->bi_iter.bi_sector;
if (!block_size_is_power_of_two(era))
(void) sector_div(block_nr, era->sectors_per_block);
else
block_nr >>= era->sectors_per_block_shift;
return block_nr;
}
static void remap_to_origin(struct era *era, struct bio *bio)
{
bio_set_dev(bio, era->origin_dev->bdev);
}
/*
*--------------------------------------------------------------
* Worker thread
*--------------------------------------------------------------
*/
static void wake_worker(struct era *era)
{
if (!atomic_read(&era->suspended))
queue_work(era->wq, &era->worker);
}
static void process_old_eras(struct era *era)
{
int r;
if (!era->digest.step)
return;
r = era->digest.step(era->md, &era->digest);
if (r < 0) {
DMERR("%s: digest step failed, stopping digestion", __func__);
era->digest.step = NULL;
} else if (era->digest.step)
wake_worker(era);
}
static void process_deferred_bios(struct era *era)
{
int r;
struct bio_list deferred_bios, marked_bios;
struct bio *bio;
struct blk_plug plug;
bool commit_needed = false;
bool failed = false;
struct writeset *ws = era->md->current_writeset;
bio_list_init(&deferred_bios);
bio_list_init(&marked_bios);
spin_lock(&era->deferred_lock);
bio_list_merge_init(&deferred_bios, &era->deferred_bios);
spin_unlock(&era->deferred_lock);
if (bio_list_empty(&deferred_bios))
return;
while ((bio = bio_list_pop(&deferred_bios))) {
r = writeset_test_and_set(&era->md->bitset_info, ws,
get_block(era, bio));
if (r < 0) {
/*
* This is bad news, we need to rollback.
* FIXME: finish.
*/
failed = true;
} else if (r == 0)
commit_needed = true;
bio_list_add(&marked_bios, bio);
}
if (commit_needed) {
r = metadata_commit(era->md);
if (r)
failed = true;
}
if (failed)
while ((bio = bio_list_pop(&marked_bios)))
bio_io_error(bio);
else {
blk_start_plug(&plug);
while ((bio = bio_list_pop(&marked_bios))) {
/*
* Only update the in-core writeset if the on-disk one
* was updated too.
*/
if (commit_needed)
set_bit(get_block(era, bio), ws->bits);
submit_bio_noacct(bio);
}
blk_finish_plug(&plug);
}
}
static void process_rpc_calls(struct era *era)
{
int r;
bool need_commit = false;
struct list_head calls;
struct rpc *rpc, *tmp;
INIT_LIST_HEAD(&calls);
spin_lock(&era->rpc_lock);
list_splice_init(&era->rpc_calls, &calls);
spin_unlock(&era->rpc_lock);
list_for_each_entry_safe(rpc, tmp, &calls, list) {
rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
need_commit = true;
}
if (need_commit) {
r = metadata_commit(era->md);
if (r)
list_for_each_entry_safe(rpc, tmp, &calls, list)
rpc->result = r;
}
list_for_each_entry_safe(rpc, tmp, &calls, list)
complete(&rpc->complete);
}
static void kick_off_digest(struct era *era)
{
if (era->md->archived_writesets) {
era->md->archived_writesets = false;
metadata_digest_start(era->md, &era->digest);
}
}
static void do_work(struct work_struct *ws)
{
struct era *era = container_of(ws, struct era, worker);
kick_off_digest(era);
process_old_eras(era);
process_deferred_bios(era);
process_rpc_calls(era);
}
static void defer_bio(struct era *era, struct bio *bio)
{
spin_lock(&era->deferred_lock);
bio_list_add(&era->deferred_bios, bio);
spin_unlock(&era->deferred_lock);
wake_worker(era);
}
/*
* Make an rpc call to the worker to change the metadata.
*/
static int perform_rpc(struct era *era, struct rpc *rpc)
{
rpc->result = 0;
init_completion(&rpc->complete);
spin_lock(&era->rpc_lock);
list_add(&rpc->list, &era->rpc_calls);
spin_unlock(&era->rpc_lock);
wake_worker(era);
wait_for_completion(&rpc->complete);
return rpc->result;
}
static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md))
{
struct rpc rpc;
rpc.fn0 = fn;
rpc.fn1 = NULL;
return perform_rpc(era, &rpc);
}
static int in_worker1(struct era *era,
int (*fn)(struct era_metadata *md, void *ref), void *arg)
{
struct rpc rpc;
rpc.fn0 = NULL;
rpc.fn1 = fn;
rpc.arg = arg;
return perform_rpc(era, &rpc);
}
static void start_worker(struct era *era)
{
atomic_set(&era->suspended, 0);
}
static void stop_worker(struct era *era)
{
atomic_set(&era->suspended, 1);
drain_workqueue(era->wq);
}
/*
*--------------------------------------------------------------
* Target methods
*--------------------------------------------------------------
*/
static void era_destroy(struct era *era)
{
if (era->md)
metadata_close(era->md);
if (era->wq)
destroy_workqueue(era->wq);
if (era->origin_dev)
dm_put_device(era->ti, era->origin_dev);
if (era->metadata_dev)
dm_put_device(era->ti, era->metadata_dev);
kfree(era);
}
static dm_block_t calc_nr_blocks(struct era *era)
{
return dm_sector_div_up(era->ti->len, era->sectors_per_block);
}
static bool valid_block_size(dm_block_t block_size)
{
bool greater_than_zero = block_size > 0;
bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
return greater_than_zero && multiple_of_min_block_size;
}
/*
* <metadata dev> <data dev> <data block size (sectors)>
*/
static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
int r;
char dummy;
struct era *era;
struct era_metadata *md;
if (argc != 3) {
ti->error = "Invalid argument count";
return -EINVAL;
}
era = kzalloc(sizeof(*era), GFP_KERNEL);
if (!era) {
ti->error = "Error allocating era structure";
return -ENOMEM;
}
era->ti = ti;
r = dm_get_device(ti, argv[0], BLK_OPEN_READ | BLK_OPEN_WRITE,
&era->metadata_dev);
if (r) {
ti->error = "Error opening metadata device";
era_destroy(era);
return -EINVAL;
}
r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE,
&era->origin_dev);
if (r) {
ti->error = "Error opening data device";
era_destroy(era);
return -EINVAL;
}
r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
if (r != 1) {
ti->error = "Error parsing block size";
era_destroy(era);
return -EINVAL;
}
r = dm_set_target_max_io_len(ti, era->sectors_per_block);
if (r) {
ti->error = "could not set max io len";
era_destroy(era);
return -EINVAL;
}
if (!valid_block_size(era->sectors_per_block)) {
ti->error = "Invalid block size";
era_destroy(era);
return -EINVAL;
}
if (era->sectors_per_block & (era->sectors_per_block - 1))
era->sectors_per_block_shift = -1;
else
era->sectors_per_block_shift = __ffs(era->sectors_per_block);
md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
if (IS_ERR(md)) {
ti->error = "Error reading metadata";
era_destroy(era);
return PTR_ERR(md);
}
era->md = md;
era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
if (!era->wq) {
ti->error = "could not create workqueue for metadata object";
era_destroy(era);
return -ENOMEM;
}
INIT_WORK(&era->worker, do_work);
spin_lock_init(&era->deferred_lock);
bio_list_init(&era->deferred_bios);
spin_lock_init(&era->rpc_lock);
INIT_LIST_HEAD(&era->rpc_calls);
ti->private = era;
ti->num_flush_bios = 1;
ti->flush_supported = true;
ti->num_discard_bios = 1;
return 0;
}
static void era_dtr(struct dm_target *ti)
{
era_destroy(ti->private);
}
static int era_map(struct dm_target *ti, struct bio *bio)
{
struct era *era = ti->private;
dm_block_t block = get_block(era, bio);
/*
* All bios get remapped to the origin device. We do this now, but
* it may not get issued until later. Depending on whether the
* block is marked in this era.
*/
remap_to_origin(era, bio);
/*
* REQ_PREFLUSH bios carry no data, so we're not interested in them.
*/
if (!(bio->bi_opf & REQ_PREFLUSH) &&
(bio_data_dir(bio) == WRITE) &&
!metadata_current_marked(era->md, block)) {
defer_bio(era, bio);
return DM_MAPIO_SUBMITTED;
}
return DM_MAPIO_REMAPPED;
}
static void era_postsuspend(struct dm_target *ti)
{
int r;
struct era *era = ti->private;
r = in_worker0(era, metadata_era_archive);
if (r) {
DMERR("%s: couldn't archive current era", __func__);
/* FIXME: fail mode */
}
stop_worker(era);
r = metadata_commit(era->md);
if (r) {
DMERR("%s: metadata_commit failed", __func__);
/* FIXME: fail mode */
}
}
static int era_preresume(struct dm_target *ti)
{
int r;
struct era *era = ti->private;
dm_block_t new_size = calc_nr_blocks(era);
if (era->nr_blocks != new_size) {
r = metadata_resize(era->md, &new_size);
if (r) {
DMERR("%s: metadata_resize failed", __func__);
return r;
}
r = metadata_commit(era->md);
if (r) {
DMERR("%s: metadata_commit failed", __func__);
return r;
}
era->nr_blocks = new_size;
}
start_worker(era);
r = in_worker0(era, metadata_era_rollover);
if (r) {
DMERR("%s: metadata_era_rollover failed", __func__);
return r;
}
return 0;
}
/*
* Status format:
*
* <metadata block size> <#used metadata blocks>/<#total metadata blocks>
* <current era> <held metadata root | '-'>
*/
static void era_status(struct dm_target *ti, status_type_t type,
unsigned int status_flags, char *result, unsigned int maxlen)
{
int r;
struct era *era = ti->private;
ssize_t sz = 0;
struct metadata_stats stats;
char buf[BDEVNAME_SIZE];
switch (type) {
case STATUSTYPE_INFO:
r = in_worker1(era, metadata_get_stats, &stats);
if (r)
goto err;
DMEMIT("%u %llu/%llu %u",
(unsigned int) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
(unsigned long long) stats.used,
(unsigned long long) stats.total,
(unsigned int) stats.era);
if (stats.snap != SUPERBLOCK_LOCATION)
DMEMIT(" %llu", stats.snap);
else
DMEMIT(" -");
break;
case STATUSTYPE_TABLE:
format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
DMEMIT("%s ", buf);
format_dev_t(buf, era->origin_dev->bdev->bd_dev);
DMEMIT("%s %u", buf, era->sectors_per_block);
break;
case STATUSTYPE_IMA:
*result = '\0';
break;
}
return;
err:
DMEMIT("Error");
}
static int era_message(struct dm_target *ti, unsigned int argc, char **argv,
char *result, unsigned int maxlen)
{
struct era *era = ti->private;
if (argc != 1) {
DMERR("incorrect number of message arguments");
return -EINVAL;
}
if (!strcasecmp(argv[0], "checkpoint"))
return in_worker0(era, metadata_checkpoint);
if (!strcasecmp(argv[0], "take_metadata_snap"))
return in_worker0(era, metadata_take_snap);
if (!strcasecmp(argv[0], "drop_metadata_snap"))
return in_worker0(era, metadata_drop_snap);
DMERR("unsupported message '%s'", argv[0]);
return -EINVAL;
}
static sector_t get_dev_size(struct dm_dev *dev)
{
return bdev_nr_sectors(dev->bdev);
}
static int era_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct era *era = ti->private;
return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
}
static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct era *era = ti->private;
uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
/*
* If the system-determined stacked limits are compatible with the
* era device's blocksize (io_opt is a factor) do not override them.
*/
if (io_opt_sectors < era->sectors_per_block ||
do_div(io_opt_sectors, era->sectors_per_block)) {
limits->io_min = 0;
limits->io_opt = era->sectors_per_block << SECTOR_SHIFT;
}
}
/*----------------------------------------------------------------*/
static struct target_type era_target = {
.name = "era",
.version = {1, 0, 0},
.module = THIS_MODULE,
.ctr = era_ctr,
.dtr = era_dtr,
.map = era_map,
.postsuspend = era_postsuspend,
.preresume = era_preresume,
.status = era_status,
.message = era_message,
.iterate_devices = era_iterate_devices,
.io_hints = era_io_hints
};
module_dm(era);
MODULE_DESCRIPTION(DM_NAME " era target");
MODULE_AUTHOR("Joe Thornber <[email protected]>");
MODULE_LICENSE("GPL");
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