// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#include "dm-transaction-manager.h"
#include "dm-space-map.h"
#include "dm-space-map-disk.h"
#include "dm-space-map-metadata.h"
#include "dm-persistent-data-internal.h"
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>
#define DM_MSG_PREFIX "transaction manager"
/*----------------------------------------------------------------*/
#define PREFETCH_SIZE 128
#define PREFETCH_BITS 7
#define PREFETCH_SENTINEL ((dm_block_t) -1ULL)
struct prefetch_set {
struct mutex lock;
dm_block_t blocks[PREFETCH_SIZE];
};
static unsigned int prefetch_hash(dm_block_t b)
{
return hash_64(b, PREFETCH_BITS);
}
static void prefetch_wipe(struct prefetch_set *p)
{
unsigned int i;
for (i = 0; i < PREFETCH_SIZE; i++)
p->blocks[i] = PREFETCH_SENTINEL;
}
static void prefetch_init(struct prefetch_set *p)
{
mutex_init(&p->lock);
prefetch_wipe(p);
}
static void prefetch_add(struct prefetch_set *p, dm_block_t b)
{
unsigned int h = prefetch_hash(b);
mutex_lock(&p->lock);
if (p->blocks[h] == PREFETCH_SENTINEL)
p->blocks[h] = b;
mutex_unlock(&p->lock);
}
static void prefetch_issue(struct prefetch_set *p, struct dm_block_manager *bm)
{
unsigned int i;
mutex_lock(&p->lock);
for (i = 0; i < PREFETCH_SIZE; i++)
if (p->blocks[i] != PREFETCH_SENTINEL) {
dm_bm_prefetch(bm, p->blocks[i]);
p->blocks[i] = PREFETCH_SENTINEL;
}
mutex_unlock(&p->lock);
}
/*----------------------------------------------------------------*/
struct shadow_info {
struct hlist_node hlist;
dm_block_t where;
};
/*
* It would be nice if we scaled with the size of transaction.
*/
#define DM_HASH_SIZE 256
#define DM_HASH_MASK (DM_HASH_SIZE - 1)
struct dm_transaction_manager {
int is_clone;
struct dm_transaction_manager *real;
struct dm_block_manager *bm;
struct dm_space_map *sm;
spinlock_t lock;
struct hlist_head buckets[DM_HASH_SIZE];
struct prefetch_set prefetches;
};
/*----------------------------------------------------------------*/
static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
{
int r = 0;
unsigned int bucket = dm_hash_block(b, DM_HASH_MASK);
struct shadow_info *si;
spin_lock(&tm->lock);
hlist_for_each_entry(si, tm->buckets + bucket, hlist)
if (si->where == b) {
r = 1;
break;
}
spin_unlock(&tm->lock);
return r;
}
/*
* This can silently fail if there's no memory. We're ok with this since
* creating redundant shadows causes no harm.
*/
static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
{
unsigned int bucket;
struct shadow_info *si;
si = kmalloc(sizeof(*si), GFP_NOIO);
if (si) {
si->where = b;
bucket = dm_hash_block(b, DM_HASH_MASK);
spin_lock(&tm->lock);
hlist_add_head(&si->hlist, tm->buckets + bucket);
spin_unlock(&tm->lock);
}
}
static void wipe_shadow_table(struct dm_transaction_manager *tm)
{
struct shadow_info *si;
struct hlist_node *tmp;
struct hlist_head *bucket;
int i;
spin_lock(&tm->lock);
for (i = 0; i < DM_HASH_SIZE; i++) {
bucket = tm->buckets + i;
hlist_for_each_entry_safe(si, tmp, bucket, hlist)
kfree(si);
INIT_HLIST_HEAD(bucket);
}
spin_unlock(&tm->lock);
}
/*----------------------------------------------------------------*/
static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
struct dm_space_map *sm)
{
int i;
struct dm_transaction_manager *tm;
tm = kmalloc(sizeof(*tm), GFP_KERNEL);
if (!tm)
return ERR_PTR(-ENOMEM);
tm->is_clone = 0;
tm->real = NULL;
tm->bm = bm;
tm->sm = sm;
spin_lock_init(&tm->lock);
for (i = 0; i < DM_HASH_SIZE; i++)
INIT_HLIST_HEAD(tm->buckets + i);
prefetch_init(&tm->prefetches);
return tm;
}
struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real)
{
struct dm_transaction_manager *tm;
tm = kmalloc(sizeof(*tm), GFP_KERNEL);
if (tm) {
tm->is_clone = 1;
tm->real = real;
}
return tm;
}
EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone);
void dm_tm_destroy(struct dm_transaction_manager *tm)
{
if (!tm)
return;
if (!tm->is_clone)
wipe_shadow_table(tm);
kfree(tm);
}
EXPORT_SYMBOL_GPL(dm_tm_destroy);
int dm_tm_pre_commit(struct dm_transaction_manager *tm)
{
int r;
if (tm->is_clone)
return -EWOULDBLOCK;
r = dm_sm_commit(tm->sm);
if (r < 0)
return r;
return dm_bm_flush(tm->bm);
}
EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
{
if (tm->is_clone)
return -EWOULDBLOCK;
wipe_shadow_table(tm);
dm_bm_unlock(root);
return dm_bm_flush(tm->bm);
}
EXPORT_SYMBOL_GPL(dm_tm_commit);
int dm_tm_new_block(struct dm_transaction_manager *tm,
const struct dm_block_validator *v,
struct dm_block **result)
{
int r;
dm_block_t new_block;
if (tm->is_clone)
return -EWOULDBLOCK;
r = dm_sm_new_block(tm->sm, &new_block);
if (r < 0)
return r;
r = dm_bm_write_lock_zero(tm->bm, new_block, v, result);
if (r < 0) {
dm_sm_dec_block(tm->sm, new_block);
return r;
}
/*
* New blocks count as shadows in that they don't need to be
* shadowed again.
*/
insert_shadow(tm, new_block);
return 0;
}
static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
const struct dm_block_validator *v,
struct dm_block **result)
{
int r;
dm_block_t new;
struct dm_block *orig_block;
r = dm_sm_new_block(tm->sm, &new);
if (r < 0)
return r;
r = dm_sm_dec_block(tm->sm, orig);
if (r < 0)
return r;
r = dm_bm_read_lock(tm->bm, orig, v, &orig_block);
if (r < 0)
return r;
/*
* It would be tempting to use dm_bm_unlock_move here, but some
* code, such as the space maps, keeps using the old data structures
* secure in the knowledge they won't be changed until the next
* transaction. Using unlock_move would force a synchronous read
* since the old block would no longer be in the cache.
*/
r = dm_bm_write_lock_zero(tm->bm, new, v, result);
if (r) {
dm_bm_unlock(orig_block);
return r;
}
memcpy(dm_block_data(*result), dm_block_data(orig_block),
dm_bm_block_size(tm->bm));
dm_bm_unlock(orig_block);
return r;
}
int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
const struct dm_block_validator *v, struct dm_block **result,
int *inc_children)
{
int r;
if (tm->is_clone)
return -EWOULDBLOCK;
r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children);
if (r < 0)
return r;
if (is_shadow(tm, orig) && !*inc_children)
return dm_bm_write_lock(tm->bm, orig, v, result);
r = __shadow_block(tm, orig, v, result);
if (r < 0)
return r;
insert_shadow(tm, dm_block_location(*result));
return r;
}
EXPORT_SYMBOL_GPL(dm_tm_shadow_block);
int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
const struct dm_block_validator *v,
struct dm_block **blk)
{
if (tm->is_clone) {
int r = dm_bm_read_try_lock(tm->real->bm, b, v, blk);
if (r == -EWOULDBLOCK)
prefetch_add(&tm->real->prefetches, b);
return r;
}
return dm_bm_read_lock(tm->bm, b, v, blk);
}
EXPORT_SYMBOL_GPL(dm_tm_read_lock);
void dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
{
dm_bm_unlock(b);
}
EXPORT_SYMBOL_GPL(dm_tm_unlock);
void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
{
/*
* The non-blocking clone doesn't support this.
*/
BUG_ON(tm->is_clone);
dm_sm_inc_block(tm->sm, b);
}
EXPORT_SYMBOL_GPL(dm_tm_inc);
void dm_tm_inc_range(struct dm_transaction_manager *tm, dm_block_t b, dm_block_t e)
{
/*
* The non-blocking clone doesn't support this.
*/
BUG_ON(tm->is_clone);
dm_sm_inc_blocks(tm->sm, b, e);
}
EXPORT_SYMBOL_GPL(dm_tm_inc_range);
void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b)
{
/*
* The non-blocking clone doesn't support this.
*/
BUG_ON(tm->is_clone);
dm_sm_dec_block(tm->sm, b);
}
EXPORT_SYMBOL_GPL(dm_tm_dec);
void dm_tm_dec_range(struct dm_transaction_manager *tm, dm_block_t b, dm_block_t e)
{
/*
* The non-blocking clone doesn't support this.
*/
BUG_ON(tm->is_clone);
dm_sm_dec_blocks(tm->sm, b, e);
}
EXPORT_SYMBOL_GPL(dm_tm_dec_range);
void dm_tm_with_runs(struct dm_transaction_manager *tm,
const __le64 *value_le, unsigned int count, dm_tm_run_fn fn)
{
uint64_t b, begin, end;
bool in_run = false;
unsigned int i;
for (i = 0; i < count; i++, value_le++) {
b = le64_to_cpu(*value_le);
if (in_run) {
if (b == end)
end++;
else {
fn(tm, begin, end);
begin = b;
end = b + 1;
}
} else {
in_run = true;
begin = b;
end = b + 1;
}
}
if (in_run)
fn(tm, begin, end);
}
EXPORT_SYMBOL_GPL(dm_tm_with_runs);
int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
uint32_t *result)
{
if (tm->is_clone)
return -EWOULDBLOCK;
return dm_sm_get_count(tm->sm, b, result);
}
int dm_tm_block_is_shared(struct dm_transaction_manager *tm, dm_block_t b,
int *result)
{
if (tm->is_clone)
return -EWOULDBLOCK;
return dm_sm_count_is_more_than_one(tm->sm, b, result);
}
struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
{
return tm->bm;
}
void dm_tm_issue_prefetches(struct dm_transaction_manager *tm)
{
prefetch_issue(&tm->prefetches, tm->bm);
}
EXPORT_SYMBOL_GPL(dm_tm_issue_prefetches);
/*----------------------------------------------------------------*/
static int dm_tm_create_internal(struct dm_block_manager *bm,
dm_block_t sb_location,
struct dm_transaction_manager **tm,
struct dm_space_map **sm,
int create,
void *sm_root, size_t sm_len)
{
int r;
*sm = dm_sm_metadata_init();
if (IS_ERR(*sm))
return PTR_ERR(*sm);
*tm = dm_tm_create(bm, *sm);
if (IS_ERR(*tm)) {
dm_sm_destroy(*sm);
return PTR_ERR(*tm);
}
if (create) {
r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
sb_location);
if (r) {
DMERR("couldn't create metadata space map");
goto bad;
}
} else {
r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len);
if (r) {
DMERR("couldn't open metadata space map");
goto bad;
}
}
return 0;
bad:
dm_tm_destroy(*tm);
dm_sm_destroy(*sm);
return r;
}
int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
struct dm_transaction_manager **tm,
struct dm_space_map **sm)
{
return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
}
EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
void *sm_root, size_t root_len,
struct dm_transaction_manager **tm,
struct dm_space_map **sm)
{
return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
}
EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
/*----------------------------------------------------------------*/
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