Orange Pi5 kernel

/*
 * 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(GFP_KERNEL, 1);
<------>if (!bio) {
<------><------>DMERR("Couldn't alloc log bio");
<------><------>goto error;
<------>}
<------>bio->bi_iter.bi_size = 0;
<------>bio->bi_iter.bi_sector = sector;
<------>bio_set_dev(bio, lc->logdev->bdev);
<------>bio->bi_end_io = (sector == WRITE_LOG_SUPER_SECTOR) ?
<------><------><------>  log_end_super : log_end_io;
<------>bio->bi_private = lc;
<------>bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
<------>page = alloc_page(GFP_KERNEL);
<------>if (!page) {
<------><------>DMERR("Couldn't alloc log page");
<------><------>bio_put(bio);
<------><------>goto error;
<------>}
 
<------>ptr = kmap_atomic(page);
<------>memcpy(ptr, entry, entrylen);
<------>if (datalen)
<------><------>memcpy(ptr + entrylen, data, datalen);
<------>memset(ptr + entrylen + datalen, 0,
<------>       lc->sectorsize - entrylen - datalen);
<------>kunmap_atomic(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 num_pages, bio_pages, pg_datalen, pg_sectorlen, i;
<------>struct page *page;
<------>struct bio *bio;
<------>size_t ret;
<------>void *ptr;
 
<------>while (datalen) {
<------><------>num_pages = ALIGN(datalen, PAGE_SIZE) >> PAGE_SHIFT;
<------><------>bio_pages = min(num_pages, BIO_MAX_PAGES);
 
<------><------>atomic_inc(&lc->io_blocks);
 
<------><------>bio = bio_alloc(GFP_KERNEL, bio_pages);
<------><------>if (!bio) {
<------><------><------>DMERR("Couldn't alloc inline data bio");
<------><------><------>goto error;
<------><------>}
 
<------><------>bio->bi_iter.bi_size = 0;
<------><------>bio->bi_iter.bi_sector = sector;
<------><------>bio_set_dev(bio, lc->logdev->bdev);
<------><------>bio->bi_end_io = log_end_io;
<------><------>bio->bi_private = lc;
<------><------>bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
<------><------>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_atomic(page);
<------><------><------>memcpy(ptr, data, pg_datalen);
<------><------><------>if (pg_sectorlen > pg_datalen)
<------><------><------><------>memset(ptr + pg_datalen, 0, pg_sectorlen - pg_datalen);
<------><------><------>kunmap_atomic(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);
error:
<------>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(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
<------>if (!bio) {
<------><------>DMERR("Couldn't alloc log bio");
<------><------>goto error;
<------>}
<------>bio->bi_iter.bi_size = 0;
<------>bio->bi_iter.bi_sector = sector;
<------>bio_set_dev(bio, lc->logdev->bdev);
<------>bio->bi_end_io = log_end_io;
<------>bio->bi_private = lc;
<------>bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
<------>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(GFP_KERNEL, min(block->vec_cnt - i, BIO_MAX_PAGES));
<------><------><------>if (!bio) {
<------><------><------><------>DMERR("Couldn't alloc log bio");
<------><------><------><------>goto error;
<------><------><------>}
<------><------><------>bio->bi_iter.bi_size = 0;
<------><------><------>bio->bi_iter.bi_sector = sector;
<------><------><------>bio_set_dev(bio, lc->logdev->bdev);
<------><------><------>bio->bi_end_io = log_end_io;
<------><------><------>bio->bi_private = lc;
<------><------><------>bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
<------><------><------>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 i_size_read(lc->logdev->bdev->bd_inode) >> SECTOR_SHIFT;
}
 
static int log_writes_kthread(void *arg)
{
<------>struct log_writes_c *lc = (struct log_writes_c *)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 *src, *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;
<------><------>}
 
<------><------>src = kmap_atomic(bv.bv_page);
<------><------>dst = kmap_atomic(page);
<------><------>memcpy(dst, src + bv.bv_offset, bv.bv_len);
<------><------>kunmap_atomic(dst);
<------><------>kunmap_atomic(src);
<------><------>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 status_flags, char *result,
<------><------><------>      unsigned maxlen)
{
<------>unsigned 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;
<------>}
}
 
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 != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
<------><------>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 argc, char **argv,
<------><------><------>      char *result, unsigned 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;
<------>struct request_queue *q = bdev_get_queue(lc->dev->bdev);
 
<------>if (!q || !blk_queue_discard(q)) {
<------><------>lc->device_supports_discard = false;
<------><------>limits->discard_granularity = lc->sectorsize;
<------><------>limits->max_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;
}
 
#if IS_ENABLED(CONFIG_DAX_DRIVER)
static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
<------><------>   struct iov_iter *i)
{
<------>struct pending_block *block;
 
<------>if (!bytes)
<------><------>return 0;
 
<------>block = kzalloc(sizeof(struct pending_block), GFP_KERNEL);
<------>if (!block) {
<------><------>DMERR("Error allocating dax pending block");
<------><------>return -ENOMEM;
<------>}
 
<------>block->data = kzalloc(bytes, GFP_KERNEL);
<------>if (!block->data) {
<------><------>DMERR("Error allocating dax data space");
<------><------>kfree(block);
<------><------>return -ENOMEM;
<------>}
 
<------>/* write data provided via the iterator */
<------>if (!copy_from_iter(block->data, bytes, i)) {
<------><------>DMERR("Error copying dax data");
<------><------>kfree(block->data);
<------><------>kfree(block);
<------><------>return -EIO;
<------>}
 
<------>/* rewind the iterator so that the block driver can use it */
<------>iov_iter_revert(i, bytes);
 
<------>block->datalen = bytes;
<------>block->sector = bio_to_dev_sectors(lc, sector);
<------>block->nr_sectors = ALIGN(bytes, lc->sectorsize) >> lc->sectorshift;
 
<------>atomic_inc(&lc->pending_blocks);
<------>spin_lock_irq(&lc->blocks_lock);
<------>list_add_tail(&block->list, &lc->unflushed_blocks);
<------>spin_unlock_irq(&lc->blocks_lock);
<------>wake_up_process(lc->log_kthread);
 
<------>return 0;
}
 
static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
<------><------><------><------><------> long nr_pages, void **kaddr, pfn_t *pfn)
{
<------>struct log_writes_c *lc = ti->private;
<------>sector_t sector = pgoff * PAGE_SECTORS;
<------>int ret;
 
<------>ret = bdev_dax_pgoff(lc->dev->bdev, sector, nr_pages * PAGE_SIZE, &pgoff);
<------>if (ret)
<------><------>return ret;
<------>return dax_direct_access(lc->dev->dax_dev, pgoff, nr_pages, kaddr, pfn);
}
 
static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
<------><------><------><------><------>    pgoff_t pgoff, void *addr, size_t bytes,
<------><------><------><------><------>    struct iov_iter *i)
{
<------>struct log_writes_c *lc = ti->private;
<------>sector_t sector = pgoff * PAGE_SECTORS;
<------>int err;
 
<------>if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
<------><------>return 0;
 
<------>/* Don't bother doing anything if logging has been disabled */
<------>if (!lc->logging_enabled)
<------><------>goto dax_copy;
 
<------>err = log_dax(lc, sector, bytes, i);
<------>if (err) {
<------><------>DMWARN("Error %d logging DAX write", err);
<------><------>return 0;
<------>}
dax_copy:
<------>return dax_copy_from_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
}
 
static size_t log_writes_dax_copy_to_iter(struct dm_target *ti,
<------><------><------><------><------>  pgoff_t pgoff, void *addr, size_t bytes,
<------><------><------><------><------>  struct iov_iter *i)
{
<------>struct log_writes_c *lc = ti->private;
<------>sector_t sector = pgoff * PAGE_SECTORS;
 
<------>if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
<------><------>return 0;
<------>return dax_copy_to_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
}
 
static int log_writes_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
<------><------><------><------><------>  size_t nr_pages)
{
<------>int ret;
<------>struct log_writes_c *lc = ti->private;
<------>sector_t sector = pgoff * PAGE_SECTORS;
 
<------>ret = bdev_dax_pgoff(lc->dev->bdev, sector, nr_pages << PAGE_SHIFT,
<------><------><------>     &pgoff);
<------>if (ret)
<------><------>return ret;
<------>return dax_zero_page_range(lc->dev->dax_dev, pgoff,
<------><------><------><------>   nr_pages << PAGE_SHIFT);
}
 
#else
#define log_writes_dax_direct_access NULL
#define log_writes_dax_copy_from_iter NULL
#define log_writes_dax_copy_to_iter NULL
#define log_writes_dax_zero_page_range 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_copy_from_iter = log_writes_dax_copy_from_iter,
<------>.dax_copy_to_iter = log_writes_dax_copy_to_iter,
<------>.dax_zero_page_range = log_writes_dax_zero_page_range,
};
 
static int __init dm_log_writes_init(void)
{
<------>int r = dm_register_target(&log_writes_target);
 
<------>if (r < 0)
<------><------>DMERR("register failed %d", r);
 
<------>return r;
}
 
static void __exit dm_log_writes_exit(void)
{
<------>dm_unregister_target(&log_writes_target);
}
 
module_init(dm_log_writes_init);
module_exit(dm_log_writes_exit);
 
MODULE_DESCRIPTION(DM_NAME " log writes target");
MODULE_AUTHOR("Josef Bacik <jbacik@fb.com>");
MODULE_LICENSE("GPL");