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- /*
- * 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,flush,fuad,b,<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[0];
- };
- 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 = sizeof(struct pending_block) + sizeof(struct bio_vec) * 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);
- }
- #else
- #define log_writes_dax_direct_access NULL
- #define log_writes_dax_copy_from_iter NULL
- #define log_writes_dax_copy_to_iter 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,
- };
- 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");
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