linux-hardened/drivers/md/dm-era-target.c
Mikulas Patocka 4c7da06f5a dm persistent data: eliminate unnecessary return values
dm_bm_unlock and dm_tm_unlock return an integer value but the returned
value is always 0.  The calling code sometimes checks the return value
and sometimes doesn't.

Eliminate these unnecessary return values and also the checks for them.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:02 -04:00

1731 lines
38 KiB
C

#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);
}
static int setup_on_disk_bitset(struct dm_disk_bitset *info,
unsigned 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 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->md.nr_bits = nr_blocks;
ws->md.root = INVALID_WRITESET_ROOT;
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)
{
int r;
memset(ws->bits, 0, bitset_size(ws->md.nr_bits));
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)
{
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.
*/
int 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_and_set_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(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(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("sb_check failed: blocknr %llu: wanted %llu",
le64_to_cpu(disk->blocknr),
(unsigned long long)dm_block_location(b));
return -ENOTBLK;
}
if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
DMERR("sb_check failed: magic %llu: wanted %llu",
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("sb_check failed: csum %u: wanted %u",
le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
return -EILSEQ;
}
return check_metadata_version(disk);
}
static 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 DM_ERA_METADATA_CACHE_SIZE 64
#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 i;
struct dm_block *b;
__le64 *data_le, zero = cpu_to_le64(0);
unsigned 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)
{
struct era_metadata *md = context;
struct writeset_disk ws_d;
dm_block_t b;
memcpy(&ws_d, value, 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)
{
struct era_metadata *md = context;
struct writeset_disk ws_d;
dm_block_t b;
memcpy(&ws_d, value, 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_metadata));
}
/*----------------------------------------------------------------*/
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);
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->block_size = le32_to_cpu(disk->data_block_size);
md->nr_blocks = le32_to_cpu(disk->nr_blocks);
md->current_era = le32_to_cpu(disk->current_era);
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,
DM_ERA_METADATA_CACHE_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 nr_bits, current_bit;
struct writeset_metadata writeset;
__le32 value;
struct dm_disk_bitset info;
int (*step)(struct era_metadata *, struct digest *);
};
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 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);
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));
/*
* We initialise another bitset info to avoid any caching side
* effects with the previous one.
*/
dm_disk_bitset_init(md->tm, &d->info);
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)
{
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__);
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__);
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);
md->current_writeset->md.root = INVALID_WRITESET_ROOT;
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->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);
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 != SUPERBLOCK_LOCATION) {
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 = save_sm_root(md);
if (r) {
DMERR("%s: save_sm_root failed", __func__);
return r;
}
r = dm_tm_pre_commit(md->tm);
if (r) {
DMERR("%s: pre commit 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_target_callbacks callbacks;
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 *);
int (*fn1)(struct era_metadata *, void *);
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->bi_bdev = 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;
bool commit_needed = false;
bool failed = false;
bio_list_init(&deferred_bios);
bio_list_init(&marked_bios);
spin_lock(&era->deferred_lock);
bio_list_merge(&deferred_bios, &era->deferred_bios);
bio_list_init(&era->deferred_bios);
spin_unlock(&era->deferred_lock);
while ((bio = bio_list_pop(&deferred_bios))) {
r = writeset_test_and_set(&era->md->bitset_info,
era->md->current_writeset,
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
while ((bio = bio_list_pop(&marked_bios)))
generic_make_request(bio);
}
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 *))
{
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 *, void *), 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);
flush_workqueue(era->wq);
}
/*----------------------------------------------------------------
* Target methods
*--------------------------------------------------------------*/
static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
{
struct request_queue *q = bdev_get_queue(dev->bdev);
return bdi_congested(&q->backing_dev_info, bdi_bits);
}
static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
{
struct era *era = container_of(cb, struct era, callbacks);
return dev_is_congested(era->origin_dev, bdi_bits);
}
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 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], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
if (r) {
ti->error = "Error opening metadata device";
era_destroy(era);
return -EINVAL;
}
r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_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->nr_blocks = calc_nr_blocks(era);
r = metadata_resize(era->md, &era->nr_blocks);
if (r) {
ti->error = "couldn't resize metadata";
era_destroy(era);
return -ENOMEM;
}
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;
ti->discards_supported = true;
era->callbacks.congested_fn = era_is_congested;
dm_table_add_target_callbacks(ti->table, &era->callbacks);
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_FLUSH bios carry no data, so we're not interested in them.
*/
if (!(bio->bi_rw & REQ_FLUSH) &&
(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);
}
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 = in_worker1(era, metadata_resize, &new_size);
if (r)
return r;
era->nr_blocks = new_size;
}
start_worker(era);
r = in_worker0(era, metadata_new_era);
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 status_flags, char *result, unsigned 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) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
(unsigned long long) stats.used,
(unsigned long long) stats.total,
(unsigned) 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;
}
return;
err:
DMEMIT("Error");
}
static int era_message(struct dm_target *ti, unsigned argc, char **argv)
{
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 i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
}
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)) {
blk_limits_io_min(limits, 0);
blk_limits_io_opt(limits, 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
};
static int __init dm_era_init(void)
{
int r;
r = dm_register_target(&era_target);
if (r) {
DMERR("era target registration failed: %d", r);
return r;
}
return 0;
}
static void __exit dm_era_exit(void)
{
dm_unregister_target(&era_target);
}
module_init(dm_era_init);
module_exit(dm_era_exit);
MODULE_DESCRIPTION(DM_NAME " era target");
MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
MODULE_LICENSE("GPL");