| /* |
| * 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/slab.h> |
| #include <linux/kthread.h> |
| #include <linux/freezer.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 WRITE_LOG_VERSION 1ULL |
| #define WRITE_LOG_MAGIC 0x6a736677736872ULL |
| |
| /* |
| * 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; |
| 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 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 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; |
| struct bio_vec *bvec; |
| int i; |
| |
| if (bio->bi_error) { |
| unsigned long flags; |
| |
| DMERR("Error writing log block, error=%d", bio->bi_error); |
| spin_lock_irqsave(&lc->blocks_lock, flags); |
| lc->logging_enabled = false; |
| spin_unlock_irqrestore(&lc->blocks_lock, flags); |
| } |
| |
| bio_for_each_segment_all(bvec, bio, i) |
| __free_page(bvec->bv_page); |
| |
| put_io_block(lc); |
| bio_put(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->bi_bdev = lc->logdev->bdev; |
| bio->bi_end_io = 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_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(WRITE, bio); |
| return 0; |
| error_bio: |
| bio_put(bio); |
| __free_page(page); |
| 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 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); |
| if (write_metadata(lc, &entry, sizeof(entry), block->data, |
| block->datalen, sector)) { |
| free_pending_block(lc, block); |
| return -1; |
| } |
| |
| if (!block->vec_cnt) |
| goto out; |
| sector++; |
| |
| 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->bi_bdev = lc->logdev->bdev; |
| 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(WRITE, 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->bi_bdev = lc->logdev->bdev; |
| 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(WRITE, 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, 0)) { |
| DMERR("Couldn't write super"); |
| return -1; |
| } |
| |
| 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++; |
| else |
| lc->next_sector += block->nr_sectors + 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() && |
| !atomic_read(&lc->pending_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); |
| lc->sectorsize = 1 << SECTOR_SHIFT; |
| 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->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; |
| } |
| |
| /* We put the super at sector 0, start logging at sector 1 */ |
| lc->next_sector = 1; |
| 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_bio_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, 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->bi_bdev = 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_rw & REQ_FLUSH); |
| bool fua_bio = (bio->bi_rw & REQ_FUA); |
| bool discard_bio = (bio->bi_rw & REQ_DISCARD); |
| |
| 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 -ENOMEM; |
| } |
| 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; |
| |
| block->sector = bio->bi_iter.bi_sector; |
| block->nr_sectors = 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 -ENOMEM; |
| } |
| |
| 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, int 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 error; |
| } |
| |
| /* |
| * 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, fmode_t *mode) |
| { |
| 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) |
| { |
| 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 = 1 << SECTOR_SHIFT; |
| limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT); |
| } |
| } |
| |
| static struct target_type log_writes_target = { |
| .name = "log-writes", |
| .version = {1, 0, 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, |
| }; |
| |
| 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"); |