diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/dev-replace.c | 1291 |
1 files changed, 1291 insertions, 0 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c new file mode 100644 index 0000000000..fe6ba17a05 --- /dev/null +++ b/fs/btrfs/dev-replace.c @@ -0,0 +1,1291 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) STRATO AG 2012. All rights reserved. + */ + +#include <linux/sched.h> +#include <linux/bio.h> +#include <linux/slab.h> +#include <linux/blkdev.h> +#include <linux/kthread.h> +#include <linux/math64.h> +#include "misc.h" +#include "ctree.h" +#include "extent_map.h" +#include "disk-io.h" +#include "transaction.h" +#include "print-tree.h" +#include "volumes.h" +#include "async-thread.h" +#include "check-integrity.h" +#include "dev-replace.h" +#include "sysfs.h" +#include "zoned.h" +#include "block-group.h" +#include "fs.h" +#include "accessors.h" +#include "scrub.h" + +/* + * Device replace overview + * + * [Objective] + * To copy all extents (both new and on-disk) from source device to target + * device, while still keeping the filesystem read-write. + * + * [Method] + * There are two main methods involved: + * + * - Write duplication + * + * All new writes will be written to both target and source devices, so even + * if replace gets canceled, sources device still contains up-to-date data. + * + * Location: handle_ops_on_dev_replace() from btrfs_map_block() + * Start: btrfs_dev_replace_start() + * End: btrfs_dev_replace_finishing() + * Content: Latest data/metadata + * + * - Copy existing extents + * + * This happens by re-using scrub facility, as scrub also iterates through + * existing extents from commit root. + * + * Location: scrub_write_block_to_dev_replace() from + * scrub_block_complete() + * Content: Data/meta from commit root. + * + * Due to the content difference, we need to avoid nocow write when dev-replace + * is happening. This is done by marking the block group read-only and waiting + * for NOCOW writes. + * + * After replace is done, the finishing part is done by swapping the target and + * source devices. + * + * Location: btrfs_dev_replace_update_device_in_mapping_tree() from + * btrfs_dev_replace_finishing() + */ + +static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, + int scrub_ret); +static int btrfs_dev_replace_kthread(void *data); + +int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info) +{ + struct btrfs_dev_lookup_args args = { .devid = BTRFS_DEV_REPLACE_DEVID }; + struct btrfs_key key; + struct btrfs_root *dev_root = fs_info->dev_root; + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + struct extent_buffer *eb; + int slot; + int ret = 0; + struct btrfs_path *path = NULL; + int item_size; + struct btrfs_dev_replace_item *ptr; + u64 src_devid; + + if (!dev_root) + return 0; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + key.objectid = 0; + key.type = BTRFS_DEV_REPLACE_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0); + if (ret) { +no_valid_dev_replace_entry_found: + /* + * We don't have a replace item or it's corrupted. If there is + * a replace target, fail the mount. + */ + if (btrfs_find_device(fs_info->fs_devices, &args)) { + btrfs_err(fs_info, + "found replace target device without a valid replace item"); + ret = -EUCLEAN; + goto out; + } + ret = 0; + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED; + dev_replace->cont_reading_from_srcdev_mode = + BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS; + dev_replace->time_started = 0; + dev_replace->time_stopped = 0; + atomic64_set(&dev_replace->num_write_errors, 0); + atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0); + dev_replace->cursor_left = 0; + dev_replace->committed_cursor_left = 0; + dev_replace->cursor_left_last_write_of_item = 0; + dev_replace->cursor_right = 0; + dev_replace->srcdev = NULL; + dev_replace->tgtdev = NULL; + dev_replace->is_valid = 0; + dev_replace->item_needs_writeback = 0; + goto out; + } + slot = path->slots[0]; + eb = path->nodes[0]; + item_size = btrfs_item_size(eb, slot); + ptr = btrfs_item_ptr(eb, slot, struct btrfs_dev_replace_item); + + if (item_size != sizeof(struct btrfs_dev_replace_item)) { + btrfs_warn(fs_info, + "dev_replace entry found has unexpected size, ignore entry"); + goto no_valid_dev_replace_entry_found; + } + + src_devid = btrfs_dev_replace_src_devid(eb, ptr); + dev_replace->cont_reading_from_srcdev_mode = + btrfs_dev_replace_cont_reading_from_srcdev_mode(eb, ptr); + dev_replace->replace_state = btrfs_dev_replace_replace_state(eb, ptr); + dev_replace->time_started = btrfs_dev_replace_time_started(eb, ptr); + dev_replace->time_stopped = + btrfs_dev_replace_time_stopped(eb, ptr); + atomic64_set(&dev_replace->num_write_errors, + btrfs_dev_replace_num_write_errors(eb, ptr)); + atomic64_set(&dev_replace->num_uncorrectable_read_errors, + btrfs_dev_replace_num_uncorrectable_read_errors(eb, ptr)); + dev_replace->cursor_left = btrfs_dev_replace_cursor_left(eb, ptr); + dev_replace->committed_cursor_left = dev_replace->cursor_left; + dev_replace->cursor_left_last_write_of_item = dev_replace->cursor_left; + dev_replace->cursor_right = btrfs_dev_replace_cursor_right(eb, ptr); + dev_replace->is_valid = 1; + + dev_replace->item_needs_writeback = 0; + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + /* + * We don't have an active replace item but if there is a + * replace target, fail the mount. + */ + if (btrfs_find_device(fs_info->fs_devices, &args)) { + btrfs_err(fs_info, +"replace without active item, run 'device scan --forget' on the target device"); + ret = -EUCLEAN; + } else { + dev_replace->srcdev = NULL; + dev_replace->tgtdev = NULL; + } + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + dev_replace->tgtdev = btrfs_find_device(fs_info->fs_devices, &args); + args.devid = src_devid; + dev_replace->srcdev = btrfs_find_device(fs_info->fs_devices, &args); + + /* + * allow 'btrfs dev replace_cancel' if src/tgt device is + * missing + */ + if (!dev_replace->srcdev && + !btrfs_test_opt(fs_info, DEGRADED)) { + ret = -EIO; + btrfs_warn(fs_info, + "cannot mount because device replace operation is ongoing and"); + btrfs_warn(fs_info, + "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?", + src_devid); + } + if (!dev_replace->tgtdev && + !btrfs_test_opt(fs_info, DEGRADED)) { + ret = -EIO; + btrfs_warn(fs_info, + "cannot mount because device replace operation is ongoing and"); + btrfs_warn(fs_info, + "tgtdev (devid %llu) is missing, need to run 'btrfs dev scan'?", + BTRFS_DEV_REPLACE_DEVID); + } + if (dev_replace->tgtdev) { + if (dev_replace->srcdev) { + dev_replace->tgtdev->total_bytes = + dev_replace->srcdev->total_bytes; + dev_replace->tgtdev->disk_total_bytes = + dev_replace->srcdev->disk_total_bytes; + dev_replace->tgtdev->commit_total_bytes = + dev_replace->srcdev->commit_total_bytes; + dev_replace->tgtdev->bytes_used = + dev_replace->srcdev->bytes_used; + dev_replace->tgtdev->commit_bytes_used = + dev_replace->srcdev->commit_bytes_used; + } + set_bit(BTRFS_DEV_STATE_REPLACE_TGT, + &dev_replace->tgtdev->dev_state); + + WARN_ON(fs_info->fs_devices->rw_devices == 0); + dev_replace->tgtdev->io_width = fs_info->sectorsize; + dev_replace->tgtdev->io_align = fs_info->sectorsize; + dev_replace->tgtdev->sector_size = fs_info->sectorsize; + dev_replace->tgtdev->fs_info = fs_info; + set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, + &dev_replace->tgtdev->dev_state); + } + break; + } + +out: + btrfs_free_path(path); + return ret; +} + +/* + * Initialize a new device for device replace target from a given source dev + * and path. + * + * Return 0 and new device in @device_out, otherwise return < 0 + */ +static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, + const char *device_path, + struct btrfs_device *srcdev, + struct btrfs_device **device_out) +{ + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + struct btrfs_device *device; + struct block_device *bdev; + u64 devid = BTRFS_DEV_REPLACE_DEVID; + int ret = 0; + + *device_out = NULL; + if (srcdev->fs_devices->seeding) { + btrfs_err(fs_info, "the filesystem is a seed filesystem!"); + return -EINVAL; + } + + bdev = blkdev_get_by_path(device_path, BLK_OPEN_WRITE, + fs_info->bdev_holder, NULL); + if (IS_ERR(bdev)) { + btrfs_err(fs_info, "target device %s is invalid!", device_path); + return PTR_ERR(bdev); + } + + if (!btrfs_check_device_zone_type(fs_info, bdev)) { + btrfs_err(fs_info, + "dev-replace: zoned type of target device mismatch with filesystem"); + ret = -EINVAL; + goto error; + } + + sync_blockdev(bdev); + + list_for_each_entry(device, &fs_devices->devices, dev_list) { + if (device->bdev == bdev) { + btrfs_err(fs_info, + "target device is in the filesystem!"); + ret = -EEXIST; + goto error; + } + } + + + if (bdev_nr_bytes(bdev) < btrfs_device_get_total_bytes(srcdev)) { + btrfs_err(fs_info, + "target device is smaller than source device!"); + ret = -EINVAL; + goto error; + } + + + device = btrfs_alloc_device(NULL, &devid, NULL, device_path); + if (IS_ERR(device)) { + ret = PTR_ERR(device); + goto error; + } + + ret = lookup_bdev(device_path, &device->devt); + if (ret) + goto error; + + set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state); + device->generation = 0; + device->io_width = fs_info->sectorsize; + device->io_align = fs_info->sectorsize; + device->sector_size = fs_info->sectorsize; + device->total_bytes = btrfs_device_get_total_bytes(srcdev); + device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev); + device->bytes_used = btrfs_device_get_bytes_used(srcdev); + device->commit_total_bytes = srcdev->commit_total_bytes; + device->commit_bytes_used = device->bytes_used; + device->fs_info = fs_info; + device->bdev = bdev; + set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); + set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state); + device->holder = fs_info->bdev_holder; + device->dev_stats_valid = 1; + set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE); + device->fs_devices = fs_devices; + + ret = btrfs_get_dev_zone_info(device, false); + if (ret) + goto error; + + mutex_lock(&fs_devices->device_list_mutex); + list_add(&device->dev_list, &fs_devices->devices); + fs_devices->num_devices++; + fs_devices->open_devices++; + mutex_unlock(&fs_devices->device_list_mutex); + + *device_out = device; + return 0; + +error: + blkdev_put(bdev, fs_info->bdev_holder); + return ret; +} + +/* + * called from commit_transaction. Writes changed device replace state to + * disk. + */ +int btrfs_run_dev_replace(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + struct btrfs_root *dev_root = fs_info->dev_root; + struct btrfs_path *path; + struct btrfs_key key; + struct extent_buffer *eb; + struct btrfs_dev_replace_item *ptr; + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + + down_read(&dev_replace->rwsem); + if (!dev_replace->is_valid || + !dev_replace->item_needs_writeback) { + up_read(&dev_replace->rwsem); + return 0; + } + up_read(&dev_replace->rwsem); + + key.objectid = 0; + key.type = BTRFS_DEV_REPLACE_KEY; + key.offset = 0; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1); + if (ret < 0) { + btrfs_warn(fs_info, + "error %d while searching for dev_replace item!", + ret); + goto out; + } + + if (ret == 0 && + btrfs_item_size(path->nodes[0], path->slots[0]) < sizeof(*ptr)) { + /* + * need to delete old one and insert a new one. + * Since no attempt is made to recover any old state, if the + * dev_replace state is 'running', the data on the target + * drive is lost. + * It would be possible to recover the state: just make sure + * that the beginning of the item is never changed and always + * contains all the essential information. Then read this + * minimal set of information and use it as a base for the + * new state. + */ + ret = btrfs_del_item(trans, dev_root, path); + if (ret != 0) { + btrfs_warn(fs_info, + "delete too small dev_replace item failed %d!", + ret); + goto out; + } + ret = 1; + } + + if (ret == 1) { + /* need to insert a new item */ + btrfs_release_path(path); + ret = btrfs_insert_empty_item(trans, dev_root, path, + &key, sizeof(*ptr)); + if (ret < 0) { + btrfs_warn(fs_info, + "insert dev_replace item failed %d!", ret); + goto out; + } + } + + eb = path->nodes[0]; + ptr = btrfs_item_ptr(eb, path->slots[0], + struct btrfs_dev_replace_item); + + down_write(&dev_replace->rwsem); + if (dev_replace->srcdev) + btrfs_set_dev_replace_src_devid(eb, ptr, + dev_replace->srcdev->devid); + else + btrfs_set_dev_replace_src_devid(eb, ptr, (u64)-1); + btrfs_set_dev_replace_cont_reading_from_srcdev_mode(eb, ptr, + dev_replace->cont_reading_from_srcdev_mode); + btrfs_set_dev_replace_replace_state(eb, ptr, + dev_replace->replace_state); + btrfs_set_dev_replace_time_started(eb, ptr, dev_replace->time_started); + btrfs_set_dev_replace_time_stopped(eb, ptr, dev_replace->time_stopped); + btrfs_set_dev_replace_num_write_errors(eb, ptr, + atomic64_read(&dev_replace->num_write_errors)); + btrfs_set_dev_replace_num_uncorrectable_read_errors(eb, ptr, + atomic64_read(&dev_replace->num_uncorrectable_read_errors)); + dev_replace->cursor_left_last_write_of_item = + dev_replace->cursor_left; + btrfs_set_dev_replace_cursor_left(eb, ptr, + dev_replace->cursor_left_last_write_of_item); + btrfs_set_dev_replace_cursor_right(eb, ptr, + dev_replace->cursor_right); + dev_replace->item_needs_writeback = 0; + up_write(&dev_replace->rwsem); + + btrfs_mark_buffer_dirty(trans, eb); + +out: + btrfs_free_path(path); + + return ret; +} + +static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info, + struct btrfs_device *src_dev) +{ + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key found_key; + struct btrfs_root *root = fs_info->dev_root; + struct btrfs_dev_extent *dev_extent = NULL; + struct btrfs_block_group *cache; + struct btrfs_trans_handle *trans; + int iter_ret = 0; + int ret = 0; + u64 chunk_offset; + + /* Do not use "to_copy" on non zoned filesystem for now */ + if (!btrfs_is_zoned(fs_info)) + return 0; + + mutex_lock(&fs_info->chunk_mutex); + + /* Ensure we don't have pending new block group */ + spin_lock(&fs_info->trans_lock); + while (fs_info->running_transaction && + !list_empty(&fs_info->running_transaction->dev_update_list)) { + spin_unlock(&fs_info->trans_lock); + mutex_unlock(&fs_info->chunk_mutex); + trans = btrfs_attach_transaction(root); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + mutex_lock(&fs_info->chunk_mutex); + if (ret == -ENOENT) { + spin_lock(&fs_info->trans_lock); + continue; + } else { + goto unlock; + } + } + + ret = btrfs_commit_transaction(trans); + mutex_lock(&fs_info->chunk_mutex); + if (ret) + goto unlock; + + spin_lock(&fs_info->trans_lock); + } + spin_unlock(&fs_info->trans_lock); + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto unlock; + } + + path->reada = READA_FORWARD; + path->search_commit_root = 1; + path->skip_locking = 1; + + key.objectid = src_dev->devid; + key.type = BTRFS_DEV_EXTENT_KEY; + key.offset = 0; + + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + struct extent_buffer *leaf = path->nodes[0]; + + if (found_key.objectid != src_dev->devid) + break; + + if (found_key.type != BTRFS_DEV_EXTENT_KEY) + break; + + if (found_key.offset < key.offset) + break; + + dev_extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent); + + chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dev_extent); + + cache = btrfs_lookup_block_group(fs_info, chunk_offset); + if (!cache) + continue; + + set_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags); + btrfs_put_block_group(cache); + } + if (iter_ret < 0) + ret = iter_ret; + + btrfs_free_path(path); +unlock: + mutex_unlock(&fs_info->chunk_mutex); + + return ret; +} + +bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev, + struct btrfs_block_group *cache, + u64 physical) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + struct extent_map *em; + struct map_lookup *map; + u64 chunk_offset = cache->start; + int num_extents, cur_extent; + int i; + + /* Do not use "to_copy" on non zoned filesystem for now */ + if (!btrfs_is_zoned(fs_info)) + return true; + + spin_lock(&cache->lock); + if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) { + spin_unlock(&cache->lock); + return true; + } + spin_unlock(&cache->lock); + + em = btrfs_get_chunk_map(fs_info, chunk_offset, 1); + ASSERT(!IS_ERR(em)); + map = em->map_lookup; + + num_extents = 0; + cur_extent = 0; + for (i = 0; i < map->num_stripes; i++) { + /* We have more device extent to copy */ + if (srcdev != map->stripes[i].dev) + continue; + + num_extents++; + if (physical == map->stripes[i].physical) + cur_extent = i; + } + + free_extent_map(em); + + if (num_extents > 1 && cur_extent < num_extents - 1) { + /* + * Has more stripes on this device. Keep this block group + * readonly until we finish all the stripes. + */ + return false; + } + + /* Last stripe on this device */ + clear_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags); + + return true; +} + +static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info, + const char *tgtdev_name, u64 srcdevid, const char *srcdev_name, + int read_src) +{ + struct btrfs_root *root = fs_info->dev_root; + struct btrfs_trans_handle *trans; + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + int ret; + struct btrfs_device *tgt_device = NULL; + struct btrfs_device *src_device = NULL; + + src_device = btrfs_find_device_by_devspec(fs_info, srcdevid, + srcdev_name); + if (IS_ERR(src_device)) + return PTR_ERR(src_device); + + if (btrfs_pinned_by_swapfile(fs_info, src_device)) { + btrfs_warn_in_rcu(fs_info, + "cannot replace device %s (devid %llu) due to active swapfile", + btrfs_dev_name(src_device), src_device->devid); + return -ETXTBSY; + } + + /* + * Here we commit the transaction to make sure commit_total_bytes + * of all the devices are updated. + */ + trans = btrfs_attach_transaction(root); + if (!IS_ERR(trans)) { + ret = btrfs_commit_transaction(trans); + if (ret) + return ret; + } else if (PTR_ERR(trans) != -ENOENT) { + return PTR_ERR(trans); + } + + ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name, + src_device, &tgt_device); + if (ret) + return ret; + + ret = mark_block_group_to_copy(fs_info, src_device); + if (ret) + return ret; + + down_write(&dev_replace->rwsem); + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + ASSERT(0); + ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED; + up_write(&dev_replace->rwsem); + goto leave; + } + + dev_replace->cont_reading_from_srcdev_mode = read_src; + dev_replace->srcdev = src_device; + dev_replace->tgtdev = tgt_device; + + btrfs_info_in_rcu(fs_info, + "dev_replace from %s (devid %llu) to %s started", + btrfs_dev_name(src_device), + src_device->devid, + btrfs_dev_name(tgt_device)); + + /* + * from now on, the writes to the srcdev are all duplicated to + * go to the tgtdev as well (refer to btrfs_map_block()). + */ + dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED; + dev_replace->time_started = ktime_get_real_seconds(); + dev_replace->cursor_left = 0; + dev_replace->committed_cursor_left = 0; + dev_replace->cursor_left_last_write_of_item = 0; + dev_replace->cursor_right = 0; + dev_replace->is_valid = 1; + dev_replace->item_needs_writeback = 1; + atomic64_set(&dev_replace->num_write_errors, 0); + atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0); + up_write(&dev_replace->rwsem); + + ret = btrfs_sysfs_add_device(tgt_device); + if (ret) + btrfs_err(fs_info, "kobj add dev failed %d", ret); + + btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); + + /* + * Commit dev_replace state and reserve 1 item for it. + * This is crucial to ensure we won't miss copying extents for new block + * groups that are allocated after we started the device replace, and + * must be done after setting up the device replace state. + */ + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + down_write(&dev_replace->rwsem); + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED; + dev_replace->srcdev = NULL; + dev_replace->tgtdev = NULL; + up_write(&dev_replace->rwsem); + goto leave; + } + + ret = btrfs_commit_transaction(trans); + WARN_ON(ret); + + /* the disk copy procedure reuses the scrub code */ + ret = btrfs_scrub_dev(fs_info, src_device->devid, 0, + btrfs_device_get_total_bytes(src_device), + &dev_replace->scrub_progress, 0, 1); + + ret = btrfs_dev_replace_finishing(fs_info, ret); + if (ret == -EINPROGRESS) + ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS; + + return ret; + +leave: + btrfs_destroy_dev_replace_tgtdev(tgt_device); + return ret; +} + +int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info, + struct btrfs_ioctl_dev_replace_args *args) +{ + int ret; + + switch (args->start.cont_reading_from_srcdev_mode) { + case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS: + case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID: + break; + default: + return -EINVAL; + } + + if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') || + args->start.tgtdev_name[0] == '\0') + return -EINVAL; + + ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name, + args->start.srcdevid, + args->start.srcdev_name, + args->start.cont_reading_from_srcdev_mode); + args->result = ret; + /* don't warn if EINPROGRESS, someone else might be running scrub */ + if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS || + ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) + return 0; + + return ret; +} + +/* + * blocked until all in-flight bios operations are finished. + */ +static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info) +{ + set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state); + wait_event(fs_info->dev_replace.replace_wait, !percpu_counter_sum( + &fs_info->dev_replace.bio_counter)); +} + +/* + * we have removed target device, it is safe to allow new bios request. + */ +static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info) +{ + clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state); + wake_up(&fs_info->dev_replace.replace_wait); +} + +/* + * When finishing the device replace, before swapping the source device with the + * target device we must update the chunk allocation state in the target device, + * as it is empty because replace works by directly copying the chunks and not + * through the normal chunk allocation path. + */ +static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev, + struct btrfs_device *tgtdev) +{ + struct extent_state *cached_state = NULL; + u64 start = 0; + u64 found_start; + u64 found_end; + int ret = 0; + + lockdep_assert_held(&srcdev->fs_info->chunk_mutex); + + while (find_first_extent_bit(&srcdev->alloc_state, start, + &found_start, &found_end, + CHUNK_ALLOCATED, &cached_state)) { + ret = set_extent_bit(&tgtdev->alloc_state, found_start, + found_end, CHUNK_ALLOCATED, NULL); + if (ret) + break; + start = found_end + 1; + } + + free_extent_state(cached_state); + return ret; +} + +static void btrfs_dev_replace_update_device_in_mapping_tree( + struct btrfs_fs_info *fs_info, + struct btrfs_device *srcdev, + struct btrfs_device *tgtdev) +{ + struct extent_map_tree *em_tree = &fs_info->mapping_tree; + struct extent_map *em; + struct map_lookup *map; + u64 start = 0; + int i; + + write_lock(&em_tree->lock); + do { + em = lookup_extent_mapping(em_tree, start, (u64)-1); + if (!em) + break; + map = em->map_lookup; + for (i = 0; i < map->num_stripes; i++) + if (srcdev == map->stripes[i].dev) + map->stripes[i].dev = tgtdev; + start = em->start + em->len; + free_extent_map(em); + } while (start); + write_unlock(&em_tree->lock); +} + +static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, + int scrub_ret) +{ + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + struct btrfs_device *tgt_device; + struct btrfs_device *src_device; + struct btrfs_root *root = fs_info->tree_root; + u8 uuid_tmp[BTRFS_UUID_SIZE]; + struct btrfs_trans_handle *trans; + int ret = 0; + + /* don't allow cancel or unmount to disturb the finishing procedure */ + mutex_lock(&dev_replace->lock_finishing_cancel_unmount); + + down_read(&dev_replace->rwsem); + /* was the operation canceled, or is it finished? */ + if (dev_replace->replace_state != + BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) { + up_read(&dev_replace->rwsem); + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + return 0; + } + + tgt_device = dev_replace->tgtdev; + src_device = dev_replace->srcdev; + up_read(&dev_replace->rwsem); + + /* + * flush all outstanding I/O and inode extent mappings before the + * copy operation is declared as being finished + */ + ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false); + if (ret) { + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + return ret; + } + btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); + + /* + * We have to use this loop approach because at this point src_device + * has to be available for transaction commit to complete, yet new + * chunks shouldn't be allocated on the device. + */ + while (1) { + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + return PTR_ERR(trans); + } + ret = btrfs_commit_transaction(trans); + WARN_ON(ret); + + /* Prevent write_all_supers() during the finishing procedure */ + mutex_lock(&fs_devices->device_list_mutex); + /* Prevent new chunks being allocated on the source device */ + mutex_lock(&fs_info->chunk_mutex); + + if (!list_empty(&src_device->post_commit_list)) { + mutex_unlock(&fs_devices->device_list_mutex); + mutex_unlock(&fs_info->chunk_mutex); + } else { + break; + } + } + + down_write(&dev_replace->rwsem); + dev_replace->replace_state = + scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED + : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED; + dev_replace->tgtdev = NULL; + dev_replace->srcdev = NULL; + dev_replace->time_stopped = ktime_get_real_seconds(); + dev_replace->item_needs_writeback = 1; + + /* + * Update allocation state in the new device and replace the old device + * with the new one in the mapping tree. + */ + if (!scrub_ret) { + scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device); + if (scrub_ret) + goto error; + btrfs_dev_replace_update_device_in_mapping_tree(fs_info, + src_device, + tgt_device); + } else { + if (scrub_ret != -ECANCELED) + btrfs_err_in_rcu(fs_info, + "btrfs_scrub_dev(%s, %llu, %s) failed %d", + btrfs_dev_name(src_device), + src_device->devid, + btrfs_dev_name(tgt_device), scrub_ret); +error: + up_write(&dev_replace->rwsem); + mutex_unlock(&fs_info->chunk_mutex); + mutex_unlock(&fs_devices->device_list_mutex); + btrfs_rm_dev_replace_blocked(fs_info); + if (tgt_device) + btrfs_destroy_dev_replace_tgtdev(tgt_device); + btrfs_rm_dev_replace_unblocked(fs_info); + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + + return scrub_ret; + } + + btrfs_info_in_rcu(fs_info, + "dev_replace from %s (devid %llu) to %s finished", + btrfs_dev_name(src_device), + src_device->devid, + btrfs_dev_name(tgt_device)); + clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &tgt_device->dev_state); + tgt_device->devid = src_device->devid; + src_device->devid = BTRFS_DEV_REPLACE_DEVID; + memcpy(uuid_tmp, tgt_device->uuid, sizeof(uuid_tmp)); + memcpy(tgt_device->uuid, src_device->uuid, sizeof(tgt_device->uuid)); + memcpy(src_device->uuid, uuid_tmp, sizeof(src_device->uuid)); + btrfs_device_set_total_bytes(tgt_device, src_device->total_bytes); + btrfs_device_set_disk_total_bytes(tgt_device, + src_device->disk_total_bytes); + btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used); + tgt_device->commit_bytes_used = src_device->bytes_used; + + btrfs_assign_next_active_device(src_device, tgt_device); + + list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list); + fs_devices->rw_devices++; + + up_write(&dev_replace->rwsem); + btrfs_rm_dev_replace_blocked(fs_info); + + btrfs_rm_dev_replace_remove_srcdev(src_device); + + btrfs_rm_dev_replace_unblocked(fs_info); + + /* + * Increment dev_stats_ccnt so that btrfs_run_dev_stats() will + * update on-disk dev stats value during commit transaction + */ + atomic_inc(&tgt_device->dev_stats_ccnt); + + /* + * this is again a consistent state where no dev_replace procedure + * is running, the target device is part of the filesystem, the + * source device is not part of the filesystem anymore and its 1st + * superblock is scratched out so that it is no longer marked to + * belong to this filesystem. + */ + mutex_unlock(&fs_info->chunk_mutex); + mutex_unlock(&fs_devices->device_list_mutex); + + /* replace the sysfs entry */ + btrfs_sysfs_remove_device(src_device); + btrfs_sysfs_update_devid(tgt_device); + if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state)) + btrfs_scratch_superblocks(fs_info, src_device->bdev, + src_device->name->str); + + /* write back the superblocks */ + trans = btrfs_start_transaction(root, 0); + if (!IS_ERR(trans)) + btrfs_commit_transaction(trans); + + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + + btrfs_rm_dev_replace_free_srcdev(src_device); + + return 0; +} + +/* + * Read progress of device replace status according to the state and last + * stored position. The value format is the same as for + * btrfs_dev_replace::progress_1000 + */ +static u64 btrfs_dev_replace_progress(struct btrfs_fs_info *fs_info) +{ + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + u64 ret = 0; + + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + ret = 0; + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + ret = 1000; + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + ret = div64_u64(dev_replace->cursor_left, + div_u64(btrfs_device_get_total_bytes( + dev_replace->srcdev), 1000)); + break; + } + + return ret; +} + +void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info, + struct btrfs_ioctl_dev_replace_args *args) +{ + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + + down_read(&dev_replace->rwsem); + /* even if !dev_replace_is_valid, the values are good enough for + * the replace_status ioctl */ + args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR; + args->status.replace_state = dev_replace->replace_state; + args->status.time_started = dev_replace->time_started; + args->status.time_stopped = dev_replace->time_stopped; + args->status.num_write_errors = + atomic64_read(&dev_replace->num_write_errors); + args->status.num_uncorrectable_read_errors = + atomic64_read(&dev_replace->num_uncorrectable_read_errors); + args->status.progress_1000 = btrfs_dev_replace_progress(fs_info); + up_read(&dev_replace->rwsem); +} + +int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info) +{ + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + struct btrfs_device *tgt_device = NULL; + struct btrfs_device *src_device = NULL; + struct btrfs_trans_handle *trans; + struct btrfs_root *root = fs_info->tree_root; + int result; + int ret; + + if (sb_rdonly(fs_info->sb)) + return -EROFS; + + mutex_lock(&dev_replace->lock_finishing_cancel_unmount); + down_write(&dev_replace->rwsem); + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED; + up_write(&dev_replace->rwsem); + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + tgt_device = dev_replace->tgtdev; + src_device = dev_replace->srcdev; + up_write(&dev_replace->rwsem); + ret = btrfs_scrub_cancel(fs_info); + if (ret < 0) { + result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED; + } else { + result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR; + /* + * btrfs_dev_replace_finishing() will handle the + * cleanup part + */ + btrfs_info_in_rcu(fs_info, + "dev_replace from %s (devid %llu) to %s canceled", + btrfs_dev_name(src_device), src_device->devid, + btrfs_dev_name(tgt_device)); + } + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + /* + * Scrub doing the replace isn't running so we need to do the + * cleanup step of btrfs_dev_replace_finishing() here + */ + result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR; + tgt_device = dev_replace->tgtdev; + src_device = dev_replace->srcdev; + dev_replace->tgtdev = NULL; + dev_replace->srcdev = NULL; + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED; + dev_replace->time_stopped = ktime_get_real_seconds(); + dev_replace->item_needs_writeback = 1; + + up_write(&dev_replace->rwsem); + + /* Scrub for replace must not be running in suspended state */ + btrfs_scrub_cancel(fs_info); + + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + return PTR_ERR(trans); + } + ret = btrfs_commit_transaction(trans); + WARN_ON(ret); + + btrfs_info_in_rcu(fs_info, + "suspended dev_replace from %s (devid %llu) to %s canceled", + btrfs_dev_name(src_device), src_device->devid, + btrfs_dev_name(tgt_device)); + + if (tgt_device) + btrfs_destroy_dev_replace_tgtdev(tgt_device); + break; + default: + up_write(&dev_replace->rwsem); + result = -EINVAL; + } + + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); + return result; +} + +void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info) +{ + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + + mutex_lock(&dev_replace->lock_finishing_cancel_unmount); + down_write(&dev_replace->rwsem); + + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED; + dev_replace->time_stopped = ktime_get_real_seconds(); + dev_replace->item_needs_writeback = 1; + btrfs_info(fs_info, "suspending dev_replace for unmount"); + break; + } + + up_write(&dev_replace->rwsem); + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); +} + +/* resume dev_replace procedure that was interrupted by unmount */ +int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info) +{ + struct task_struct *task; + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + + down_write(&dev_replace->rwsem); + + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + up_write(&dev_replace->rwsem); + return 0; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + break; + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED; + break; + } + if (!dev_replace->tgtdev || !dev_replace->tgtdev->bdev) { + btrfs_info(fs_info, + "cannot continue dev_replace, tgtdev is missing"); + btrfs_info(fs_info, + "you may cancel the operation after 'mount -o degraded'"); + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED; + up_write(&dev_replace->rwsem); + return 0; + } + up_write(&dev_replace->rwsem); + + /* + * This could collide with a paused balance, but the exclusive op logic + * should never allow both to start and pause. We don't want to allow + * dev-replace to start anyway. + */ + if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) { + down_write(&dev_replace->rwsem); + dev_replace->replace_state = + BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED; + up_write(&dev_replace->rwsem); + btrfs_info(fs_info, + "cannot resume dev-replace, other exclusive operation running"); + return 0; + } + + task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl"); + return PTR_ERR_OR_ZERO(task); +} + +static int btrfs_dev_replace_kthread(void *data) +{ + struct btrfs_fs_info *fs_info = data; + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; + u64 progress; + int ret; + + progress = btrfs_dev_replace_progress(fs_info); + progress = div_u64(progress, 10); + btrfs_info_in_rcu(fs_info, + "continuing dev_replace from %s (devid %llu) to target %s @%u%%", + btrfs_dev_name(dev_replace->srcdev), + dev_replace->srcdev->devid, + btrfs_dev_name(dev_replace->tgtdev), + (unsigned int)progress); + + ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid, + dev_replace->committed_cursor_left, + btrfs_device_get_total_bytes(dev_replace->srcdev), + &dev_replace->scrub_progress, 0, 1); + ret = btrfs_dev_replace_finishing(fs_info, ret); + WARN_ON(ret && ret != -ECANCELED); + + btrfs_exclop_finish(fs_info); + return 0; +} + +int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace) +{ + if (!dev_replace->is_valid) + return 0; + + switch (dev_replace->replace_state) { + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: + return 0; + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: + /* + * return true even if tgtdev is missing (this is + * something that can happen if the dev_replace + * procedure is suspended by an umount and then + * the tgtdev is missing (or "btrfs dev scan") was + * not called and the filesystem is remounted + * in degraded state. This does not stop the + * dev_replace procedure. It needs to be canceled + * manually if the cancellation is wanted. + */ + break; + } + return 1; +} + +void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount) +{ + percpu_counter_sub(&fs_info->dev_replace.bio_counter, amount); + cond_wake_up_nomb(&fs_info->dev_replace.replace_wait); +} + +void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info) +{ + while (1) { + percpu_counter_inc(&fs_info->dev_replace.bio_counter); + if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING, + &fs_info->fs_state))) + break; + + btrfs_bio_counter_dec(fs_info); + wait_event(fs_info->dev_replace.replace_wait, + !test_bit(BTRFS_FS_STATE_DEV_REPLACING, + &fs_info->fs_state)); + } +} |