// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.
*/
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/bitops.h>
#include <linux/bitmap.h>
#include <linux/device-mapper.h>
#include "persistent-data/dm-bitset.h"
#include "persistent-data/dm-space-map.h"
#include "persistent-data/dm-block-manager.h"
#include "persistent-data/dm-transaction-manager.h"
#include "dm-clone-metadata.h"
#define DM_MSG_PREFIX "clone metadata"
#define SUPERBLOCK_LOCATION 0
#define SUPERBLOCK_MAGIC 0x8af27f64
#define SUPERBLOCK_CSUM_XOR 257649492
#define DM_CLONE_MAX_CONCURRENT_LOCKS 5
#define UUID_LEN 16
/* Min and max dm-clone metadata versions supported */
#define DM_CLONE_MIN_METADATA_VERSION 1
#define DM_CLONE_MAX_METADATA_VERSION 1
/*
* On-disk metadata layout
*/
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];
__le64 region_size;
__le64 target_size;
__le64 bitset_root;
} __packed;
/*
* Region and Dirty bitmaps.
*
* dm-clone logically splits the source and destination devices in regions of
* fixed size. The destination device's regions are gradually hydrated, i.e.,
* we copy (clone) the source's regions to the destination device. Eventually,
* all regions will get hydrated and all I/O will be served from the
* destination device.
*
* We maintain an on-disk bitmap which tracks the state of each of the
* destination device's regions, i.e., whether they are hydrated or not.
*
* To save constantly doing look ups on disk we keep an in core copy of the
* on-disk bitmap, the region_map.
*
* In order to track which regions are hydrated during a metadata transaction,
* we use a second set of bitmaps, the dmap (dirty bitmap), which includes two
* bitmaps, namely dirty_regions and dirty_words. The dirty_regions bitmap
* tracks the regions that got hydrated during the current metadata
* transaction. The dirty_words bitmap tracks the dirty words, i.e. longs, of
* the dirty_regions bitmap.
*
* This allows us to precisely track the regions that were hydrated during the
* current metadata transaction and update the metadata accordingly, when we
* commit the current transaction. This is important because dm-clone should
* only commit the metadata of regions that were properly flushed to the
* destination device beforehand. Otherwise, in case of a crash, we could end
* up with a corrupted dm-clone device.
*
* When a region finishes hydrating dm-clone calls
* dm_clone_set_region_hydrated(), or for discard requests
* dm_clone_cond_set_range(), which sets the corresponding bits in region_map
* and dmap.
*
* During a metadata commit we scan dmap->dirty_words and dmap->dirty_regions
* and update the on-disk metadata accordingly. Thus, we don't have to flush to
* disk the whole region_map. We can just flush the dirty region_map bits.
*
* We use the helper dmap->dirty_words bitmap, which is smaller than the
* original region_map, to reduce the amount of memory accesses during a
* metadata commit. Moreover, as dm-bitset also accesses the on-disk bitmap in
* 64-bit word granularity, the dirty_words bitmap helps us avoid useless disk
* accesses.
*
* We could update directly the on-disk bitmap, when dm-clone calls either
* dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), buts this
* inserts significant metadata I/O overhead in dm-clone's I/O path. Also, as
* these two functions don't block, we can call them in interrupt context,
* e.g., in a hooked overwrite bio's completion routine, and further reduce the
* I/O completion latency.
*
* We maintain two dirty bitmap sets. During a metadata commit we atomically
* swap the currently used dmap with the unused one. This allows the metadata
* update functions to run concurrently with an ongoing commit.
*/
struct dirty_map {
unsigned long *dirty_words;
unsigned long *dirty_regions;
unsigned int changed;
};
struct dm_clone_metadata {
/* The metadata block device */
struct block_device *bdev;
sector_t target_size;
sector_t region_size;
unsigned long nr_regions;
unsigned long nr_words;
/* Spinlock protecting the region and dirty bitmaps. */
spinlock_t bitmap_lock;
struct dirty_map dmap[2];
struct dirty_map *current_dmap;
/* Protected by lock */
struct dirty_map *committing_dmap;
/*
* In core copy of the on-disk bitmap to save constantly doing look ups
* on disk.
*/
unsigned long *region_map;
/* Protected by bitmap_lock */
unsigned int read_only;
struct dm_block_manager *bm;
struct dm_space_map *sm;
struct dm_transaction_manager *tm;
struct rw_semaphore lock;
struct dm_disk_bitset bitset_info;
dm_block_t bitset_root;
/*
* 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];
bool hydration_done:1;
bool fail_io:1;
};
/*---------------------------------------------------------------------------*/
/*
* 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 *sb;
u32 csum;
sb = dm_block_data(b);
sb->blocknr = cpu_to_le64(dm_block_location(b));
csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR);
sb->csum = cpu_to_le32(csum);
}
static int sb_check(const struct dm_block_validator *v, struct dm_block *b,
size_t sb_block_size)
{
struct superblock_disk *sb;
u32 csum, metadata_version;
sb = dm_block_data(b);
if (dm_block_location(b) != le64_to_cpu(sb->blocknr)) {
DMERR("Superblock check failed: blocknr %llu, expected %llu",
le64_to_cpu(sb->blocknr),
(unsigned long long)dm_block_location(b));
return -ENOTBLK;
}
if (le64_to_cpu(sb->magic) != SUPERBLOCK_MAGIC) {
DMERR("Superblock check failed: magic %llu, expected %llu",
le64_to_cpu(sb->magic),
(unsigned long long)SUPERBLOCK_MAGIC);
return -EILSEQ;
}
csum = dm_bm_checksum(&sb->flags, sb_block_size - sizeof(__le32),
SUPERBLOCK_CSUM_XOR);
if (sb->csum != cpu_to_le32(csum)) {
DMERR("Superblock check failed: checksum %u, expected %u",
csum, le32_to_cpu(sb->csum));
return -EILSEQ;
}
/* Check metadata version */
metadata_version = le32_to_cpu(sb->version);
if (metadata_version < DM_CLONE_MIN_METADATA_VERSION ||
metadata_version > DM_CLONE_MAX_METADATA_VERSION) {
DMERR("Clone metadata version %u found, but only versions between %u and %u supported.",
metadata_version, DM_CLONE_MIN_METADATA_VERSION,
DM_CLONE_MAX_METADATA_VERSION);
return -EINVAL;
}
return 0;
}
static const struct dm_block_validator sb_validator = {
.name = "superblock",
.prepare_for_write = sb_prepare_for_write,
.check = sb_check
};
/*
* Check if the superblock is formatted or not. We consider the superblock to
* be formatted in case we find non-zero bytes in it.
*/
static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *formatted)
{
int r;
unsigned int i, nr_words;
struct dm_block *sblock;
__le64 *data_le, zero = cpu_to_le64(0);
/*
* We don't use a validator here because the superblock could be all
* zeroes.
*/
r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &sblock);
if (r) {
DMERR("Failed to read_lock superblock");
return r;
}
data_le = dm_block_data(sblock);
*formatted = false;
/* This assumes that the block size is a multiple of 8 bytes */
BUG_ON(dm_bm_block_size(bm) % sizeof(__le64));
nr_words = dm_bm_block_size(bm) / sizeof(__le64);
for (i = 0; i < nr_words; i++) {
if (data_le[i] != zero) {
*formatted = true;
break;
}
}
dm_bm_unlock(sblock);
return 0;
}
/*---------------------------------------------------------------------------*/
/*
* Low-level metadata handling.
*/
static inline int superblock_read_lock(struct dm_clone_metadata *cmd,
struct dm_block **sblock)
{
return dm_bm_read_lock(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock);
}
static inline int superblock_write_lock_zero(struct dm_clone_metadata *cmd,
struct dm_block **sblock)
{
return dm_bm_write_lock_zero(cmd->bm, SUPERBLOCK_LOCATION, &sb_validator, sblock);
}
static int __copy_sm_root(struct dm_clone_metadata *cmd)
{
int r;
size_t root_size;
r = dm_sm_root_size(cmd->sm, &root_size);
if (r)
return r;
return dm_sm_copy_root(cmd->sm, &cmd->metadata_space_map_root, root_size);
}
/* Save dm-clone metadata in superblock */
static void __prepare_superblock(struct dm_clone_metadata *cmd,
struct superblock_disk *sb)
{
sb->flags = cpu_to_le32(0UL);
/* FIXME: UUID is currently unused */
memset(sb->uuid, 0, sizeof(sb->uuid));
sb->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
sb->version = cpu_to_le32(DM_CLONE_MAX_METADATA_VERSION);
/* Save the metadata space_map root */
memcpy(&sb->metadata_space_map_root, &cmd->metadata_space_map_root,
sizeof(cmd->metadata_space_map_root));
sb->region_size = cpu_to_le64(cmd->region_size);
sb->target_size = cpu_to_le64(cmd->target_size);
sb->bitset_root = cpu_to_le64(cmd->bitset_root);
}
static int __open_metadata(struct dm_clone_metadata *cmd)
{
int r;
struct dm_block *sblock;
struct superblock_disk *sb;
r = superblock_read_lock(cmd, &sblock);
if (r) {
DMERR("Failed to read_lock superblock");
return r;
}
sb = dm_block_data(sblock);
/* Verify that target_size and region_size haven't changed. */
if (cmd->region_size != le64_to_cpu(sb->region_size) ||
cmd->target_size != le64_to_cpu(sb->target_size)) {
DMERR("Region and/or target size don't match the ones in metadata");
r = -EINVAL;
goto out_with_lock;
}
r = dm_tm_open_with_sm(cmd->bm, SUPERBLOCK_LOCATION,
sb->metadata_space_map_root,
sizeof(sb->metadata_space_map_root),
&cmd->tm, &cmd->sm);
if (r) {
DMERR("dm_tm_open_with_sm failed");
goto out_with_lock;
}
dm_disk_bitset_init(cmd->tm, &cmd->bitset_info);
cmd->bitset_root = le64_to_cpu(sb->bitset_root);
out_with_lock:
dm_bm_unlock(sblock);
return r;
}
static int __format_metadata(struct dm_clone_metadata *cmd)
{
int r;
struct dm_block *sblock;
struct superblock_disk *sb;
r = dm_tm_create_with_sm(cmd->bm, SUPERBLOCK_LOCATION, &cmd->tm, &cmd->sm);
if (r) {
DMERR("Failed to create transaction manager");
return r;
}
dm_disk_bitset_init(cmd->tm, &cmd->bitset_info);
r = dm_bitset_empty(&cmd->bitset_info, &cmd->bitset_root);
if (r) {
DMERR("Failed to create empty on-disk bitset");
goto err_with_tm;
}
r = dm_bitset_resize(&cmd->bitset_info, cmd->bitset_root, 0,
cmd->nr_regions, false, &cmd->bitset_root);
if (r) {
DMERR("Failed to resize on-disk bitset to %lu entries", cmd->nr_regions);
goto err_with_tm;
}
/* Flush to disk all blocks, except the superblock */
r = dm_tm_pre_commit(cmd->tm);
if (r) {
DMERR("dm_tm_pre_commit failed");
goto err_with_tm;
}
r = __copy_sm_root(cmd);
if (r) {
DMERR("__copy_sm_root failed");
goto err_with_tm;
}
r = superblock_write_lock_zero(cmd, &sblock);
if (r) {
DMERR("Failed to write_lock superblock");
goto err_with_tm;
}
sb = dm_block_data(sblock);
__prepare_superblock(cmd, sb);
r = dm_tm_commit(cmd->tm, sblock);
if (r) {
DMERR("Failed to commit superblock");
goto err_with_tm;
}
return 0;
err_with_tm:
dm_sm_destroy(cmd->sm);
dm_tm_destroy(cmd->tm);
return r;
}
static int __open_or_format_metadata(struct dm_clone_metadata *cmd, bool may_format_device)
{
int r;
bool formatted = false;
r = __superblock_all_zeroes(cmd->bm, &formatted);
if (r)
return r;
if (!formatted)
return may_format_device ? __format_metadata(cmd) : -EPERM;
return __open_metadata(cmd);
}
static int __create_persistent_data_structures(struct dm_clone_metadata *cmd,
bool may_format_device)
{
int r;
/* Create block manager */
cmd->bm = dm_block_manager_create(cmd->bdev,
DM_CLONE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
DM_CLONE_MAX_CONCURRENT_LOCKS);
if (IS_ERR(cmd->bm)) {
DMERR("Failed to create block manager");
return PTR_ERR(cmd->bm);
}
r = __open_or_format_metadata(cmd, may_format_device);
if (r)
dm_block_manager_destroy(cmd->bm);
return r;
}
static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd)
{
dm_sm_destroy(cmd->sm);
dm_tm_destroy(cmd->tm);
dm_block_manager_destroy(cmd->bm);
}
/*---------------------------------------------------------------------------*/
static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words,
unsigned long nr_regions)
{
dmap->changed = 0;
dmap->dirty_words = kvzalloc(bitmap_size(nr_words), GFP_KERNEL);
if (!dmap->dirty_words)
return -ENOMEM;
dmap->dirty_regions = kvzalloc(bitmap_size(nr_regions), GFP_KERNEL);
if (!dmap->dirty_regions) {
kvfree(dmap->dirty_words);
return -ENOMEM;
}
return 0;
}
static void __dirty_map_exit(struct dirty_map *dmap)
{
kvfree(dmap->dirty_words);
kvfree(dmap->dirty_regions);
}
static int dirty_map_init(struct dm_clone_metadata *cmd)
{
if (__dirty_map_init(&cmd->dmap[0], cmd->nr_words, cmd->nr_regions)) {
DMERR("Failed to allocate dirty bitmap");
return -ENOMEM;
}
if (__dirty_map_init(&cmd->dmap[1], cmd->nr_words, cmd->nr_regions)) {
DMERR("Failed to allocate dirty bitmap");
__dirty_map_exit(&cmd->dmap[0]);
return -ENOMEM;
}
cmd->current_dmap = &cmd->dmap[0];
cmd->committing_dmap = NULL;
return 0;
}
static void dirty_map_exit(struct dm_clone_metadata *cmd)
{
__dirty_map_exit(&cmd->dmap[0]);
__dirty_map_exit(&cmd->dmap[1]);
}
static int __load_bitset_in_core(struct dm_clone_metadata *cmd)
{
int r;
unsigned long i;
struct dm_bitset_cursor c;
/* Flush bitset cache */
r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root);
if (r)
return r;
r = dm_bitset_cursor_begin(&cmd->bitset_info, cmd->bitset_root, cmd->nr_regions, &c);
if (r)
return r;
for (i = 0; ; i++) {
__assign_bit(i, cmd->region_map, dm_bitset_cursor_get_value(&c));
if (i >= (cmd->nr_regions - 1))
break;
r = dm_bitset_cursor_next(&c);
if (r)
break;
}
dm_bitset_cursor_end(&c);
return r;
}
struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev,
sector_t target_size,
sector_t region_size)
{
int r;
struct dm_clone_metadata *cmd;
cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
if (!cmd) {
DMERR("Failed to allocate memory for dm-clone metadata");
return ERR_PTR(-ENOMEM);
}
cmd->bdev = bdev;
cmd->target_size = target_size;
cmd->region_size = region_size;
cmd->nr_regions = dm_sector_div_up(cmd->target_size, cmd->region_size);
cmd->nr_words = BITS_TO_LONGS(cmd->nr_regions);
init_rwsem(&cmd->lock);
spin_lock_init(&cmd->bitmap_lock);
cmd->read_only = 0;
cmd->fail_io = false;
cmd->hydration_done = false;
cmd->region_map = kvmalloc(bitmap_size(cmd->nr_regions), GFP_KERNEL);
if (!cmd->region_map) {
DMERR("Failed to allocate memory for region bitmap");
r = -ENOMEM;
goto out_with_md;
}
r = __create_persistent_data_structures(cmd, true);
if (r)
goto out_with_region_map;
r = __load_bitset_in_core(cmd);
if (r) {
DMERR("Failed to load on-disk region map");
goto out_with_pds;
}
r = dirty_map_init(cmd);
if (r)
goto out_with_pds;
if (bitmap_full(cmd->region_map, cmd->nr_regions))
cmd->hydration_done = true;
return cmd;
out_with_pds:
__destroy_persistent_data_structures(cmd);
out_with_region_map:
kvfree(cmd->region_map);
out_with_md:
kfree(cmd);
return ERR_PTR(r);
}
void dm_clone_metadata_close(struct dm_clone_metadata *cmd)
{
if (!cmd->fail_io)
__destroy_persistent_data_structures(cmd);
dirty_map_exit(cmd);
kvfree(cmd->region_map);
kfree(cmd);
}
bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd)
{
return cmd->hydration_done;
}
bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr)
{
return dm_clone_is_hydration_done(cmd) || test_bit(region_nr, cmd->region_map);
}
bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd,
unsigned long start, unsigned long nr_regions)
{
unsigned long bit;
if (dm_clone_is_hydration_done(cmd))
return true;
bit = find_next_zero_bit(cmd->region_map, cmd->nr_regions, start);
return (bit >= (start + nr_regions));
}
unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd)
{
return bitmap_weight(cmd->region_map, cmd->nr_regions);
}
unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd,
unsigned long start)
{
return find_next_zero_bit(cmd->region_map, cmd->nr_regions, start);
}
static int __update_metadata_word(struct dm_clone_metadata *cmd,
unsigned long *dirty_regions,
unsigned long word)
{
int r;
unsigned long index = word * BITS_PER_LONG;
unsigned long max_index = min(cmd->nr_regions, (word + 1) * BITS_PER_LONG);
while (index < max_index) {
if (test_bit(index, dirty_regions)) {
r = dm_bitset_set_bit(&cmd->bitset_info, cmd->bitset_root,
index, &cmd->bitset_root);
if (r) {
DMERR("dm_bitset_set_bit failed");
return r;
}
__clear_bit(index, dirty_regions);
}
index++;
}
return 0;
}
static int __metadata_commit(struct dm_clone_metadata *cmd)
{
int r;
struct dm_block *sblock;
struct superblock_disk *sb;
/* Flush bitset cache */
r = dm_bitset_flush(&cmd->bitset_info, cmd->bitset_root, &cmd->bitset_root);
if (r) {
DMERR("dm_bitset_flush failed");
return r;
}
/* Flush to disk all blocks, except the superblock */
r = dm_tm_pre_commit(cmd->tm);
if (r) {
DMERR("dm_tm_pre_commit failed");
return r;
}
/* Save the space map root in cmd->metadata_space_map_root */
r = __copy_sm_root(cmd);
if (r) {
DMERR("__copy_sm_root failed");
return r;
}
/* Lock the superblock */
r = superblock_write_lock_zero(cmd, &sblock);
if (r) {
DMERR("Failed to write_lock superblock");
return r;
}
/* Save the metadata in superblock */
sb = dm_block_data(sblock);
__prepare_superblock(cmd, sb);
/* Unlock superblock and commit it to disk */
r = dm_tm_commit(cmd->tm, sblock);
if (r) {
DMERR("Failed to commit superblock");
return r;
}
/*
* FIXME: Find a more efficient way to check if the hydration is done.
*/
if (bitmap_full(cmd->region_map, cmd->nr_regions))
cmd->hydration_done = true;
return 0;
}
static int __flush_dmap(struct dm_clone_metadata *cmd, struct dirty_map *dmap)
{
int r;
unsigned long word;
word = 0;
do {
word = find_next_bit(dmap->dirty_words, cmd->nr_words, word);
if (word == cmd->nr_words)
break;
r = __update_metadata_word(cmd, dmap->dirty_regions, word);
if (r)
return r;
__clear_bit(word, dmap->dirty_words);
word++;
} while (word < cmd->nr_words);
r = __metadata_commit(cmd);
if (r)
return r;
/* Update the changed flag */
spin_lock_irq(&cmd->bitmap_lock);
dmap->changed = 0;
spin_unlock_irq(&cmd->bitmap_lock);
return 0;
}
int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd)
{
int r = 0;
struct dirty_map *dmap, *next_dmap;
down_write(&cmd->lock);
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
r = -EPERM;
goto out;
}
/* Get current dirty bitmap */
dmap = cmd->current_dmap;
/* Get next dirty bitmap */
next_dmap = (dmap == &cmd->dmap[0]) ? &cmd->dmap[1] : &cmd->dmap[0];
/*
* The last commit failed, so we don't have a clean dirty-bitmap to
* use.
*/
if (WARN_ON(next_dmap->changed || cmd->committing_dmap)) {
r = -EINVAL;
goto out;
}
/* Swap dirty bitmaps */
spin_lock_irq(&cmd->bitmap_lock);
cmd->current_dmap = next_dmap;
spin_unlock_irq(&cmd->bitmap_lock);
/* Set old dirty bitmap as currently committing */
cmd->committing_dmap = dmap;
out:
up_write(&cmd->lock);
return r;
}
int dm_clone_metadata_commit(struct dm_clone_metadata *cmd)
{
int r = -EPERM;
down_write(&cmd->lock);
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm))
goto out;
if (WARN_ON(!cmd->committing_dmap)) {
r = -EINVAL;
goto out;
}
r = __flush_dmap(cmd, cmd->committing_dmap);
if (!r) {
/* Clear committing dmap */
cmd->committing_dmap = NULL;
}
out:
up_write(&cmd->lock);
return r;
}
int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr)
{
int r = 0;
struct dirty_map *dmap;
unsigned long word, flags;
if (unlikely(region_nr >= cmd->nr_regions)) {
DMERR("Region %lu out of range (total number of regions %lu)",
region_nr, cmd->nr_regions);
return -ERANGE;
}
word = region_nr / BITS_PER_LONG;
spin_lock_irqsave(&cmd->bitmap_lock, flags);
if (cmd->read_only) {
r = -EPERM;
goto out;
}
dmap = cmd->current_dmap;
__set_bit(word, dmap->dirty_words);
__set_bit(region_nr, dmap->dirty_regions);
__set_bit(region_nr, cmd->region_map);
dmap->changed = 1;
out:
spin_unlock_irqrestore(&cmd->bitmap_lock, flags);
return r;
}
int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,
unsigned long nr_regions)
{
int r = 0;
struct dirty_map *dmap;
unsigned long word, region_nr;
if (unlikely(start >= cmd->nr_regions || (start + nr_regions) < start ||
(start + nr_regions) > cmd->nr_regions)) {
DMERR("Invalid region range: start %lu, nr_regions %lu (total number of regions %lu)",
start, nr_regions, cmd->nr_regions);
return -ERANGE;
}
spin_lock_irq(&cmd->bitmap_lock);
if (cmd->read_only) {
r = -EPERM;
goto out;
}
dmap = cmd->current_dmap;
for (region_nr = start; region_nr < (start + nr_regions); region_nr++) {
if (!test_bit(region_nr, cmd->region_map)) {
word = region_nr / BITS_PER_LONG;
__set_bit(word, dmap->dirty_words);
__set_bit(region_nr, dmap->dirty_regions);
__set_bit(region_nr, cmd->region_map);
dmap->changed = 1;
}
}
out:
spin_unlock_irq(&cmd->bitmap_lock);
return r;
}
/*
* WARNING: This must not be called concurrently with either
* dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it changes
* cmd->region_map without taking the cmd->bitmap_lock spinlock. The only
* exception is after setting the metadata to read-only mode, using
* dm_clone_metadata_set_read_only().
*
* We don't take the spinlock because __load_bitset_in_core() does I/O, so it
* may block.
*/
int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd)
{
int r = -EINVAL;
down_write(&cmd->lock);
if (cmd->fail_io)
goto out;
r = __load_bitset_in_core(cmd);
out:
up_write(&cmd->lock);
return r;
}
bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd)
{
bool r;
unsigned long flags;
spin_lock_irqsave(&cmd->bitmap_lock, flags);
r = cmd->dmap[0].changed || cmd->dmap[1].changed;
spin_unlock_irqrestore(&cmd->bitmap_lock, flags);
return r;
}
int dm_clone_metadata_abort(struct dm_clone_metadata *cmd)
{
int r = -EPERM;
down_write(&cmd->lock);
if (cmd->fail_io || dm_bm_is_read_only(cmd->bm))
goto out;
__destroy_persistent_data_structures(cmd);
r = __create_persistent_data_structures(cmd, false);
if (r) {
/* If something went wrong we can neither write nor read the metadata */
cmd->fail_io = true;
}
out:
up_write(&cmd->lock);
return r;
}
void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd)
{
down_write(&cmd->lock);
spin_lock_irq(&cmd->bitmap_lock);
cmd->read_only = 1;
spin_unlock_irq(&cmd->bitmap_lock);
if (!cmd->fail_io)
dm_bm_set_read_only(cmd->bm);
up_write(&cmd->lock);
}
void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd)
{
down_write(&cmd->lock);
spin_lock_irq(&cmd->bitmap_lock);
cmd->read_only = 0;
spin_unlock_irq(&cmd->bitmap_lock);
if (!cmd->fail_io)
dm_bm_set_read_write(cmd->bm);
up_write(&cmd->lock);
}
int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd,
dm_block_t *result)
{
int r = -EINVAL;
down_read(&cmd->lock);
if (!cmd->fail_io)
r = dm_sm_get_nr_free(cmd->sm, result);
up_read(&cmd->lock);
return r;
}
int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd,
dm_block_t *result)
{
int r = -EINVAL;
down_read(&cmd->lock);
if (!cmd->fail_io)
r = dm_sm_get_nr_blocks(cmd->sm, result);
up_read(&cmd->lock);
return r;
}
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