// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2014 Facebook. All rights reserved.
*
* This file is released under the GPL.
*/
#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/uio.h>
#define DM_MSG_PREFIX "log-writes"
/*
* This target will sequentially log all writes to the target device onto the
* log device. This is helpful for replaying writes to check for fs consistency
* at all times. This target provides a mechanism to mark specific events to
* check data at a later time. So for example you would:
*
* write data
* fsync
* dmsetup message /dev/whatever mark mymark
* unmount /mnt/test
*
* Then replay the log up to mymark and check the contents of the replay to
* verify it matches what was written.
*
* We log writes only after they have been flushed, this makes the log describe
* close to the order in which the data hits the actual disk, not its cache. So
* for example the following sequence (W means write, C means complete)
*
* Wa,Wb,Wc,Cc,Ca,FLUSH,FUAd,Cb,CFLUSH,CFUAd
*
* Would result in the log looking like this:
*
* c,a,b,flush,fuad,<other writes>,<next flush>
*
* This is meant to help expose problems where file systems do not properly wait
* on data being written before invoking a FLUSH. FUA bypasses cache so once it
* completes it is added to the log as it should be on disk.
*
* We treat DISCARDs as if they don't bypass cache so that they are logged in
* order of completion along with the normal writes. If we didn't do it this
* way we would process all the discards first and then write all the data, when
* in fact we want to do the data and the discard in the order that they
* completed.
*/
#define LOG_FLUSH_FLAG (1 << 0)
#define LOG_FUA_FLAG (1 << 1)
#define LOG_DISCARD_FLAG (1 << 2)
#define LOG_MARK_FLAG (1 << 3)
#define LOG_METADATA_FLAG (1 << 4)
#define WRITE_LOG_VERSION 1ULL
#define WRITE_LOG_MAGIC 0x6a736677736872ULL
#define WRITE_LOG_SUPER_SECTOR 0
/*
* The disk format for this is braindead simple.
*
* At byte 0 we have our super, followed by the following sequence for
* nr_entries:
*
* [ 1 sector ][ entry->nr_sectors ]
* [log_write_entry][ data written ]
*
* The log_write_entry takes up a full sector so we can have arbitrary length
* marks and it leaves us room for extra content in the future.
*/
/*
* Basic info about the log for userspace.
*/
struct log_write_super {
__le64 magic;
__le64 version;
__le64 nr_entries;
__le32 sectorsize;
};
/*
* sector - the sector we wrote.
* nr_sectors - the number of sectors we wrote.
* flags - flags for this log entry.
* data_len - the size of the data in this log entry, this is for private log
* entry stuff, the MARK data provided by userspace for example.
*/
struct log_write_entry {
__le64 sector;
__le64 nr_sectors;
__le64 flags;
__le64 data_len;
};
struct log_writes_c {
struct dm_dev *dev;
struct dm_dev *logdev;
u64 logged_entries;
u32 sectorsize;
u32 sectorshift;
atomic_t io_blocks;
atomic_t pending_blocks;
sector_t next_sector;
sector_t end_sector;
bool logging_enabled;
bool device_supports_discard;
spinlock_t blocks_lock;
struct list_head unflushed_blocks;
struct list_head logging_blocks;
wait_queue_head_t wait;
struct task_struct *log_kthread;
struct completion super_done;
};
struct pending_block {
int vec_cnt;
u64 flags;
sector_t sector;
sector_t nr_sectors;
char *data;
u32 datalen;
struct list_head list;
struct bio_vec vecs[];
};
struct per_bio_data {
struct pending_block *block;
};
static inline sector_t bio_to_dev_sectors(struct log_writes_c *lc,
sector_t sectors)
{
return sectors >> (lc->sectorshift - SECTOR_SHIFT);
}
static inline sector_t dev_to_bio_sectors(struct log_writes_c *lc,
sector_t sectors)
{
return sectors << (lc->sectorshift - SECTOR_SHIFT);
}
static void put_pending_block(struct log_writes_c *lc)
{
if (atomic_dec_and_test(&lc->pending_blocks)) {
smp_mb__after_atomic();
if (waitqueue_active(&lc->wait))
wake_up(&lc->wait);
}
}
static void put_io_block(struct log_writes_c *lc)
{
if (atomic_dec_and_test(&lc->io_blocks)) {
smp_mb__after_atomic();
if (waitqueue_active(&lc->wait))
wake_up(&lc->wait);
}
}
static void log_end_io(struct bio *bio)
{
struct log_writes_c *lc = bio->bi_private;
if (bio->bi_status) {
unsigned long flags;
DMERR("Error writing log block, error=%d", bio->bi_status);
spin_lock_irqsave(&lc->blocks_lock, flags);
lc->logging_enabled = false;
spin_unlock_irqrestore(&lc->blocks_lock, flags);
}
bio_free_pages(bio);
put_io_block(lc);
bio_put(bio);
}
static void log_end_super(struct bio *bio)
{
struct log_writes_c *lc = bio->bi_private;
complete(&lc->super_done);
log_end_io(bio);
}
/*
* Meant to be called if there is an error, it will free all the pages
* associated with the block.
*/
static void free_pending_block(struct log_writes_c *lc,
struct pending_block *block)
{
int i;
for (i = 0; i < block->vec_cnt; i++) {
if (block->vecs[i].bv_page)
__free_page(block->vecs[i].bv_page);
}
kfree(block->data);
kfree(block);
put_pending_block(lc);
}
static int write_metadata(struct log_writes_c *lc, void *entry,
size_t entrylen, void *data, size_t datalen,
sector_t sector)
{
struct bio *bio;
struct page *page;
void *ptr;
size_t ret;
bio = bio_alloc(lc->logdev->bdev, 1, REQ_OP_WRITE, GFP_KERNEL);
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio->bi_end_io = (sector == WRITE_LOG_SUPER_SECTOR) ?
log_end_super : log_end_io;
bio->bi_private = lc;
page = alloc_page(GFP_KERNEL);
if (!page) {
DMERR("Couldn't alloc log page");
bio_put(bio);
goto error;
}
ptr = kmap_local_page(page);
memcpy(ptr, entry, entrylen);
if (datalen)
memcpy(ptr + entrylen, data, datalen);
memset(ptr + entrylen + datalen, 0,
lc->sectorsize - entrylen - datalen);
kunmap_local(ptr);
ret = bio_add_page(bio, page, lc->sectorsize, 0);
if (ret != lc->sectorsize) {
DMERR("Couldn't add page to the log block");
goto error_bio;
}
submit_bio(bio);
return 0;
error_bio:
bio_put(bio);
__free_page(page);
error:
put_io_block(lc);
return -1;
}
static int write_inline_data(struct log_writes_c *lc, void *entry,
size_t entrylen, void *data, size_t datalen,
sector_t sector)
{
int bio_pages, pg_datalen, pg_sectorlen, i;
struct page *page;
struct bio *bio;
size_t ret;
void *ptr;
while (datalen) {
bio_pages = bio_max_segs(DIV_ROUND_UP(datalen, PAGE_SIZE));
atomic_inc(&lc->io_blocks);
bio = bio_alloc(lc->logdev->bdev, bio_pages, REQ_OP_WRITE,
GFP_KERNEL);
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio->bi_end_io = log_end_io;
bio->bi_private = lc;
for (i = 0; i < bio_pages; i++) {
pg_datalen = min_t(int, datalen, PAGE_SIZE);
pg_sectorlen = ALIGN(pg_datalen, lc->sectorsize);
page = alloc_page(GFP_KERNEL);
if (!page) {
DMERR("Couldn't alloc inline data page");
goto error_bio;
}
ptr = kmap_local_page(page);
memcpy(ptr, data, pg_datalen);
if (pg_sectorlen > pg_datalen)
memset(ptr + pg_datalen, 0, pg_sectorlen - pg_datalen);
kunmap_local(ptr);
ret = bio_add_page(bio, page, pg_sectorlen, 0);
if (ret != pg_sectorlen) {
DMERR("Couldn't add page of inline data");
__free_page(page);
goto error_bio;
}
datalen -= pg_datalen;
data += pg_datalen;
}
submit_bio(bio);
sector += bio_pages * PAGE_SECTORS;
}
return 0;
error_bio:
bio_free_pages(bio);
bio_put(bio);
put_io_block(lc);
return -1;
}
static int log_one_block(struct log_writes_c *lc,
struct pending_block *block, sector_t sector)
{
struct bio *bio;
struct log_write_entry entry;
size_t metadatalen, ret;
int i;
entry.sector = cpu_to_le64(block->sector);
entry.nr_sectors = cpu_to_le64(block->nr_sectors);
entry.flags = cpu_to_le64(block->flags);
entry.data_len = cpu_to_le64(block->datalen);
metadatalen = (block->flags & LOG_MARK_FLAG) ? block->datalen : 0;
if (write_metadata(lc, &entry, sizeof(entry), block->data,
metadatalen, sector)) {
free_pending_block(lc, block);
return -1;
}
sector += dev_to_bio_sectors(lc, 1);
if (block->datalen && metadatalen == 0) {
if (write_inline_data(lc, &entry, sizeof(entry), block->data,
block->datalen, sector)) {
free_pending_block(lc, block);
return -1;
}
/* we don't support both inline data & bio data */
goto out;
}
if (!block->vec_cnt)
goto out;
atomic_inc(&lc->io_blocks);
bio = bio_alloc(lc->logdev->bdev, bio_max_segs(block->vec_cnt),
REQ_OP_WRITE, GFP_KERNEL);
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio->bi_end_io = log_end_io;
bio->bi_private = lc;
for (i = 0; i < block->vec_cnt; i++) {
/*
* The page offset is always 0 because we allocate a new page
* for every bvec in the original bio for simplicity sake.
*/
ret = bio_add_page(bio, block->vecs[i].bv_page,
block->vecs[i].bv_len, 0);
if (ret != block->vecs[i].bv_len) {
atomic_inc(&lc->io_blocks);
submit_bio(bio);
bio = bio_alloc(lc->logdev->bdev,
bio_max_segs(block->vec_cnt - i),
REQ_OP_WRITE, GFP_KERNEL);
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio->bi_end_io = log_end_io;
bio->bi_private = lc;
ret = bio_add_page(bio, block->vecs[i].bv_page,
block->vecs[i].bv_len, 0);
if (ret != block->vecs[i].bv_len) {
DMERR("Couldn't add page on new bio?");
bio_put(bio);
goto error;
}
}
sector += block->vecs[i].bv_len >> SECTOR_SHIFT;
}
submit_bio(bio);
out:
kfree(block->data);
kfree(block);
put_pending_block(lc);
return 0;
error:
free_pending_block(lc, block);
put_io_block(lc);
return -1;
}
static int log_super(struct log_writes_c *lc)
{
struct log_write_super super;
super.magic = cpu_to_le64(WRITE_LOG_MAGIC);
super.version = cpu_to_le64(WRITE_LOG_VERSION);
super.nr_entries = cpu_to_le64(lc->logged_entries);
super.sectorsize = cpu_to_le32(lc->sectorsize);
if (write_metadata(lc, &super, sizeof(super), NULL, 0,
WRITE_LOG_SUPER_SECTOR)) {
DMERR("Couldn't write super");
return -1;
}
/*
* Super sector should be writen in-order, otherwise the
* nr_entries could be rewritten incorrectly by an old bio.
*/
wait_for_completion_io(&lc->super_done);
return 0;
}
static inline sector_t logdev_last_sector(struct log_writes_c *lc)
{
return bdev_nr_sectors(lc->logdev->bdev);
}
static int log_writes_kthread(void *arg)
{
struct log_writes_c *lc = arg;
sector_t sector = 0;
while (!kthread_should_stop()) {
bool super = false;
bool logging_enabled;
struct pending_block *block = NULL;
int ret;
spin_lock_irq(&lc->blocks_lock);
if (!list_empty(&lc->logging_blocks)) {
block = list_first_entry(&lc->logging_blocks,
struct pending_block, list);
list_del_init(&block->list);
if (!lc->logging_enabled)
goto next;
sector = lc->next_sector;
if (!(block->flags & LOG_DISCARD_FLAG))
lc->next_sector += dev_to_bio_sectors(lc, block->nr_sectors);
lc->next_sector += dev_to_bio_sectors(lc, 1);
/*
* Apparently the size of the device may not be known
* right away, so handle this properly.
*/
if (!lc->end_sector)
lc->end_sector = logdev_last_sector(lc);
if (lc->end_sector &&
lc->next_sector >= lc->end_sector) {
DMERR("Ran out of space on the logdev");
lc->logging_enabled = false;
goto next;
}
lc->logged_entries++;
atomic_inc(&lc->io_blocks);
super = (block->flags & (LOG_FUA_FLAG | LOG_MARK_FLAG));
if (super)
atomic_inc(&lc->io_blocks);
}
next:
logging_enabled = lc->logging_enabled;
spin_unlock_irq(&lc->blocks_lock);
if (block) {
if (logging_enabled) {
ret = log_one_block(lc, block, sector);
if (!ret && super)
ret = log_super(lc);
if (ret) {
spin_lock_irq(&lc->blocks_lock);
lc->logging_enabled = false;
spin_unlock_irq(&lc->blocks_lock);
}
} else
free_pending_block(lc, block);
continue;
}
if (!try_to_freeze()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop() &&
list_empty(&lc->logging_blocks))
schedule();
__set_current_state(TASK_RUNNING);
}
}
return 0;
}
/*
* Construct a log-writes mapping:
* log-writes <dev_path> <log_dev_path>
*/
static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct log_writes_c *lc;
struct dm_arg_set as;
const char *devname, *logdevname;
int ret;
as.argc = argc;
as.argv = argv;
if (argc < 2) {
ti->error = "Invalid argument count";
return -EINVAL;
}
lc = kzalloc(sizeof(struct log_writes_c), GFP_KERNEL);
if (!lc) {
ti->error = "Cannot allocate context";
return -ENOMEM;
}
spin_lock_init(&lc->blocks_lock);
INIT_LIST_HEAD(&lc->unflushed_blocks);
INIT_LIST_HEAD(&lc->logging_blocks);
init_waitqueue_head(&lc->wait);
init_completion(&lc->super_done);
atomic_set(&lc->io_blocks, 0);
atomic_set(&lc->pending_blocks, 0);
devname = dm_shift_arg(&as);
ret = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &lc->dev);
if (ret) {
ti->error = "Device lookup failed";
goto bad;
}
logdevname = dm_shift_arg(&as);
ret = dm_get_device(ti, logdevname, dm_table_get_mode(ti->table),
&lc->logdev);
if (ret) {
ti->error = "Log device lookup failed";
dm_put_device(ti, lc->dev);
goto bad;
}
lc->sectorsize = bdev_logical_block_size(lc->dev->bdev);
lc->sectorshift = ilog2(lc->sectorsize);
lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
if (IS_ERR(lc->log_kthread)) {
ret = PTR_ERR(lc->log_kthread);
ti->error = "Couldn't alloc kthread";
dm_put_device(ti, lc->dev);
dm_put_device(ti, lc->logdev);
goto bad;
}
/*
* next_sector is in 512b sectors to correspond to what bi_sector expects.
* The super starts at sector 0, and the next_sector is the next logical
* one based on the sectorsize of the device.
*/
lc->next_sector = lc->sectorsize >> SECTOR_SHIFT;
lc->logging_enabled = true;
lc->end_sector = logdev_last_sector(lc);
lc->device_supports_discard = true;
ti->num_flush_bios = 1;
ti->flush_supported = true;
ti->num_discard_bios = 1;
ti->discards_supported = true;
ti->per_io_data_size = sizeof(struct per_bio_data);
ti->private = lc;
return 0;
bad:
kfree(lc);
return ret;
}
static int log_mark(struct log_writes_c *lc, char *data)
{
struct pending_block *block;
size_t maxsize = lc->sectorsize - sizeof(struct log_write_entry);
block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
if (!block) {
DMERR("Error allocating pending block");
return -ENOMEM;
}
block->data = kstrndup(data, maxsize - 1, GFP_KERNEL);
if (!block->data) {
DMERR("Error copying mark data");
kfree(block);
return -ENOMEM;
}
atomic_inc(&lc->pending_blocks);
block->datalen = strlen(block->data);
block->flags |= LOG_MARK_FLAG;
spin_lock_irq(&lc->blocks_lock);
list_add_tail(&block->list, &lc->logging_blocks);
spin_unlock_irq(&lc->blocks_lock);
wake_up_process(lc->log_kthread);
return 0;
}
static void log_writes_dtr(struct dm_target *ti)
{
struct log_writes_c *lc = ti->private;
spin_lock_irq(&lc->blocks_lock);
list_splice_init(&lc->unflushed_blocks, &lc->logging_blocks);
spin_unlock_irq(&lc->blocks_lock);
/*
* This is just nice to have since it'll update the super to include the
* unflushed blocks, if it fails we don't really care.
*/
log_mark(lc, "dm-log-writes-end");
wake_up_process(lc->log_kthread);
wait_event(lc->wait, !atomic_read(&lc->io_blocks) &&
!atomic_read(&lc->pending_blocks));
kthread_stop(lc->log_kthread);
WARN_ON(!list_empty(&lc->logging_blocks));
WARN_ON(!list_empty(&lc->unflushed_blocks));
dm_put_device(ti, lc->dev);
dm_put_device(ti, lc->logdev);
kfree(lc);
}
static void normal_map_bio(struct dm_target *ti, struct bio *bio)
{
struct log_writes_c *lc = ti->private;
bio_set_dev(bio, lc->dev->bdev);
}
static int log_writes_map(struct dm_target *ti, struct bio *bio)
{
struct log_writes_c *lc = ti->private;
struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
struct pending_block *block;
struct bvec_iter iter;
struct bio_vec bv;
size_t alloc_size;
int i = 0;
bool flush_bio = (bio->bi_opf & REQ_PREFLUSH);
bool fua_bio = (bio->bi_opf & REQ_FUA);
bool discard_bio = (bio_op(bio) == REQ_OP_DISCARD);
bool meta_bio = (bio->bi_opf & REQ_META);
pb->block = NULL;
/* Don't bother doing anything if logging has been disabled */
if (!lc->logging_enabled)
goto map_bio;
/*
* Map reads as normal.
*/
if (bio_data_dir(bio) == READ)
goto map_bio;
/* No sectors and not a flush? Don't care */
if (!bio_sectors(bio) && !flush_bio)
goto map_bio;
/*
* Discards will have bi_size set but there's no actual data, so just
* allocate the size of the pending block.
*/
if (discard_bio)
alloc_size = sizeof(struct pending_block);
else
alloc_size = struct_size(block, vecs, bio_segments(bio));
block = kzalloc(alloc_size, GFP_NOIO);
if (!block) {
DMERR("Error allocating pending block");
spin_lock_irq(&lc->blocks_lock);
lc->logging_enabled = false;
spin_unlock_irq(&lc->blocks_lock);
return DM_MAPIO_KILL;
}
INIT_LIST_HEAD(&block->list);
pb->block = block;
atomic_inc(&lc->pending_blocks);
if (flush_bio)
block->flags |= LOG_FLUSH_FLAG;
if (fua_bio)
block->flags |= LOG_FUA_FLAG;
if (discard_bio)
block->flags |= LOG_DISCARD_FLAG;
if (meta_bio)
block->flags |= LOG_METADATA_FLAG;
block->sector = bio_to_dev_sectors(lc, bio->bi_iter.bi_sector);
block->nr_sectors = bio_to_dev_sectors(lc, bio_sectors(bio));
/* We don't need the data, just submit */
if (discard_bio) {
WARN_ON(flush_bio || fua_bio);
if (lc->device_supports_discard)
goto map_bio;
bio_endio(bio);
return DM_MAPIO_SUBMITTED;
}
/* Flush bio, splice the unflushed blocks onto this list and submit */
if (flush_bio && !bio_sectors(bio)) {
spin_lock_irq(&lc->blocks_lock);
list_splice_init(&lc->unflushed_blocks, &block->list);
spin_unlock_irq(&lc->blocks_lock);
goto map_bio;
}
/*
* We will write this bio somewhere else way later so we need to copy
* the actual contents into new pages so we know the data will always be
* there.
*
* We do this because this could be a bio from O_DIRECT in which case we
* can't just hold onto the page until some later point, we have to
* manually copy the contents.
*/
bio_for_each_segment(bv, bio, iter) {
struct page *page;
void *dst;
page = alloc_page(GFP_NOIO);
if (!page) {
DMERR("Error allocing page");
free_pending_block(lc, block);
spin_lock_irq(&lc->blocks_lock);
lc->logging_enabled = false;
spin_unlock_irq(&lc->blocks_lock);
return DM_MAPIO_KILL;
}
dst = kmap_local_page(page);
memcpy_from_bvec(dst, &bv);
kunmap_local(dst);
block->vecs[i].bv_page = page;
block->vecs[i].bv_len = bv.bv_len;
block->vec_cnt++;
i++;
}
/* Had a flush with data in it, weird */
if (flush_bio) {
spin_lock_irq(&lc->blocks_lock);
list_splice_init(&lc->unflushed_blocks, &block->list);
spin_unlock_irq(&lc->blocks_lock);
}
map_bio:
normal_map_bio(ti, bio);
return DM_MAPIO_REMAPPED;
}
static int normal_end_io(struct dm_target *ti, struct bio *bio,
blk_status_t *error)
{
struct log_writes_c *lc = ti->private;
struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
if (bio_data_dir(bio) == WRITE && pb->block) {
struct pending_block *block = pb->block;
unsigned long flags;
spin_lock_irqsave(&lc->blocks_lock, flags);
if (block->flags & LOG_FLUSH_FLAG) {
list_splice_tail_init(&block->list, &lc->logging_blocks);
list_add_tail(&block->list, &lc->logging_blocks);
wake_up_process(lc->log_kthread);
} else if (block->flags & LOG_FUA_FLAG) {
list_add_tail(&block->list, &lc->logging_blocks);
wake_up_process(lc->log_kthread);
} else
list_add_tail(&block->list, &lc->unflushed_blocks);
spin_unlock_irqrestore(&lc->blocks_lock, flags);
}
return DM_ENDIO_DONE;
}
/*
* INFO format: <logged entries> <highest allocated sector>
*/
static void log_writes_status(struct dm_target *ti, status_type_t type,
unsigned int status_flags, char *result,
unsigned int maxlen)
{
unsigned int sz = 0;
struct log_writes_c *lc = ti->private;
switch (type) {
case STATUSTYPE_INFO:
DMEMIT("%llu %llu", lc->logged_entries,
(unsigned long long)lc->next_sector - 1);
if (!lc->logging_enabled)
DMEMIT(" logging_disabled");
break;
case STATUSTYPE_TABLE:
DMEMIT("%s %s", lc->dev->name, lc->logdev->name);
break;
case STATUSTYPE_IMA:
*result = '\0';
break;
}
}
static int log_writes_prepare_ioctl(struct dm_target *ti,
struct block_device **bdev)
{
struct log_writes_c *lc = ti->private;
struct dm_dev *dev = lc->dev;
*bdev = dev->bdev;
/*
* Only pass ioctls through if the device sizes match exactly.
*/
if (ti->len != bdev_nr_sectors(dev->bdev))
return 1;
return 0;
}
static int log_writes_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn,
void *data)
{
struct log_writes_c *lc = ti->private;
return fn(ti, lc->dev, 0, ti->len, data);
}
/*
* Messages supported:
* mark <mark data> - specify the marked data.
*/
static int log_writes_message(struct dm_target *ti, unsigned int argc, char **argv,
char *result, unsigned int maxlen)
{
int r = -EINVAL;
struct log_writes_c *lc = ti->private;
if (argc != 2) {
DMWARN("Invalid log-writes message arguments, expect 2 arguments, got %d", argc);
return r;
}
if (!strcasecmp(argv[0], "mark"))
r = log_mark(lc, argv[1]);
else
DMWARN("Unrecognised log writes target message received: %s", argv[0]);
return r;
}
static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct log_writes_c *lc = ti->private;
if (!bdev_max_discard_sectors(lc->dev->bdev)) {
lc->device_supports_discard = false;
limits->discard_granularity = lc->sectorsize;
limits->max_hw_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
}
limits->logical_block_size = bdev_logical_block_size(lc->dev->bdev);
limits->physical_block_size = bdev_physical_block_size(lc->dev->bdev);
limits->io_min = limits->physical_block_size;
limits->dma_alignment = limits->logical_block_size - 1;
}
#if IS_ENABLED(CONFIG_FS_DAX)
static struct dax_device *log_writes_dax_pgoff(struct dm_target *ti,
pgoff_t *pgoff)
{
struct log_writes_c *lc = ti->private;
*pgoff += (get_start_sect(lc->dev->bdev) >> PAGE_SECTORS_SHIFT);
return lc->dev->dax_dev;
}
static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, enum dax_access_mode mode, void **kaddr,
pfn_t *pfn)
{
struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
}
static int log_writes_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
size_t nr_pages)
{
struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
return dax_zero_page_range(dax_dev, pgoff, nr_pages << PAGE_SHIFT);
}
static size_t log_writes_dax_recovery_write(struct dm_target *ti,
pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
{
struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
}
#else
#define log_writes_dax_direct_access NULL
#define log_writes_dax_zero_page_range NULL
#define log_writes_dax_recovery_write NULL
#endif
static struct target_type log_writes_target = {
.name = "log-writes",
.version = {1, 1, 0},
.module = THIS_MODULE,
.ctr = log_writes_ctr,
.dtr = log_writes_dtr,
.map = log_writes_map,
.end_io = normal_end_io,
.status = log_writes_status,
.prepare_ioctl = log_writes_prepare_ioctl,
.message = log_writes_message,
.iterate_devices = log_writes_iterate_devices,
.io_hints = log_writes_io_hints,
.direct_access = log_writes_dax_direct_access,
.dax_zero_page_range = log_writes_dax_zero_page_range,
.dax_recovery_write = log_writes_dax_recovery_write,
};
module_dm(log_writes);
MODULE_DESCRIPTION(DM_NAME " log writes target");
MODULE_AUTHOR("Josef Bacik <[email protected]>");
MODULE_LICENSE("GPL");
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