v4.19.13 snapshot.
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
new file mode 100644
index 0000000..9814347
--- /dev/null
+++ b/fs/btrfs/dev-replace.c
@@ -0,0 +1,1042 @@
+// 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 "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 "rcu-string.h"
+#include "dev-replace.h"
+#include "sysfs.h"
+
+static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
+ int scrub_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);
+static int btrfs_dev_replace_kthread(void *data);
+
+int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
+{
+ 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;
+
+ 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:
+ ret = 0;
+ dev_replace->replace_state =
+ BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED;
+ dev_replace->cont_reading_from_srcdev_mode =
+ BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
+ dev_replace->replace_state = 0;
+ 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_nr(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:
+ 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->srcdev = btrfs_find_device(fs_info, src_devid,
+ NULL, NULL);
+ dev_replace->tgtdev = btrfs_find_device(fs_info,
+ BTRFS_DEV_REPLACE_DEVID,
+ NULL, NULL);
+ /*
+ * 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_device *device;
+ struct block_device *bdev;
+ struct list_head *devices;
+ struct rcu_string *name;
+ u64 devid = BTRFS_DEV_REPLACE_DEVID;
+ int ret = 0;
+
+ *device_out = NULL;
+ if (fs_info->fs_devices->seeding) {
+ btrfs_err(fs_info, "the filesystem is a seed filesystem!");
+ return -EINVAL;
+ }
+
+ bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
+ fs_info->bdev_holder);
+ if (IS_ERR(bdev)) {
+ btrfs_err(fs_info, "target device %s is invalid!", device_path);
+ return PTR_ERR(bdev);
+ }
+
+ filemap_write_and_wait(bdev->bd_inode->i_mapping);
+
+ devices = &fs_info->fs_devices->devices;
+ list_for_each_entry(device, devices, dev_list) {
+ if (device->bdev == bdev) {
+ btrfs_err(fs_info,
+ "target device is in the filesystem!");
+ ret = -EEXIST;
+ goto error;
+ }
+ }
+
+
+ if (i_size_read(bdev->bd_inode) <
+ 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);
+ if (IS_ERR(device)) {
+ ret = PTR_ERR(device);
+ goto error;
+ }
+
+ name = rcu_string_strdup(device_path, GFP_KERNEL);
+ if (!name) {
+ btrfs_free_device(device);
+ ret = -ENOMEM;
+ goto error;
+ }
+ rcu_assign_pointer(device->name, name);
+
+ mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ 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->mode = FMODE_EXCL;
+ device->dev_stats_valid = 1;
+ set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
+ device->fs_devices = fs_info->fs_devices;
+ list_add(&device->dev_list, &fs_info->fs_devices->devices);
+ fs_info->fs_devices->num_devices++;
+ fs_info->fs_devices->open_devices++;
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+
+ *device_out = device;
+ return 0;
+
+error:
+ blkdev_put(bdev, FMODE_EXCL);
+ 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)
+{
+ 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;
+
+ btrfs_dev_replace_read_lock(dev_replace);
+ if (!dev_replace->is_valid ||
+ !dev_replace->item_needs_writeback) {
+ btrfs_dev_replace_read_unlock(dev_replace);
+ return 0;
+ }
+ btrfs_dev_replace_read_unlock(dev_replace);
+
+ 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_nr(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);
+
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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;
+ btrfs_dev_replace_write_unlock(dev_replace);
+
+ btrfs_mark_buffer_dirty(eb);
+
+out:
+ btrfs_free_path(path);
+
+ return ret;
+}
+
+void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
+
+ dev_replace->committed_cursor_left =
+ dev_replace->cursor_left_last_write_of_item;
+}
+
+static char* btrfs_dev_name(struct btrfs_device *device)
+{
+ if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
+ return "<missing disk>";
+ else
+ return rcu_str_deref(device->name);
+}
+
+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;
+
+ ret = btrfs_find_device_by_devspec(fs_info, srcdevid,
+ srcdev_name, &src_device);
+ if (ret)
+ return ret;
+
+ ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
+ src_device, &tgt_device);
+ if (ret)
+ return ret;
+
+ /*
+ * 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);
+ }
+
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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;
+ goto leave;
+ }
+
+ dev_replace->cont_reading_from_srcdev_mode = read_src;
+ WARN_ON(!src_device);
+ 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,
+ rcu_str_deref(tgt_device->name));
+
+ /*
+ * 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);
+ btrfs_dev_replace_write_unlock(dev_replace);
+
+ ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, 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);
+
+ /* force writing the updated state information to disk */
+ trans = btrfs_start_transaction(root, 0);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ btrfs_dev_replace_write_lock(dev_replace);
+ dev_replace->replace_state =
+ BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
+ dev_replace->srcdev = NULL;
+ dev_replace->tgtdev = NULL;
+ 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;
+ } else {
+ WARN_ON(ret);
+ }
+
+ return ret;
+
+leave:
+ btrfs_dev_replace_write_unlock(dev_replace);
+ 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 = 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->replace_wait, !percpu_counter_sum(
+ &fs_info->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->replace_wait);
+}
+
+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_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);
+
+ btrfs_dev_replace_read_lock(dev_replace);
+ /* was the operation canceled, or is it finished? */
+ if (dev_replace->replace_state !=
+ BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
+ btrfs_dev_replace_read_unlock(dev_replace);
+ mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
+ return 0;
+ }
+
+ tgt_device = dev_replace->tgtdev;
+ src_device = dev_replace->srcdev;
+ btrfs_dev_replace_read_unlock(dev_replace);
+
+ /*
+ * 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, -1);
+ if (ret) {
+ mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
+ return ret;
+ }
+ btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-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);
+
+ /* keep away write_all_supers() during the finishing procedure */
+ mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ mutex_lock(&fs_info->chunk_mutex);
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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;
+
+ /* replace old device with new one in mapping tree */
+ if (!scrub_ret) {
+ btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
+ src_device,
+ tgt_device);
+ } else {
+ btrfs_err_in_rcu(fs_info,
+ "btrfs_scrub_dev(%s, %llu, %s) failed %d",
+ btrfs_dev_name(src_device),
+ src_device->devid,
+ rcu_str_deref(tgt_device->name), scrub_ret);
+ btrfs_dev_replace_write_unlock(dev_replace);
+ mutex_unlock(&fs_info->chunk_mutex);
+ mutex_unlock(&fs_info->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,
+ rcu_str_deref(tgt_device->name));
+ 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);
+ ASSERT(list_empty(&src_device->resized_list));
+ tgt_device->commit_total_bytes = src_device->commit_total_bytes;
+ 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_info->fs_devices->alloc_list);
+ fs_info->fs_devices->rw_devices++;
+
+ btrfs_dev_replace_write_unlock(dev_replace);
+
+ 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_info->fs_devices->device_list_mutex);
+
+ /* replace the sysfs entry */
+ btrfs_sysfs_rm_device_link(fs_info->fs_devices, src_device);
+ btrfs_rm_dev_replace_free_srcdev(fs_info, src_device);
+
+ /* 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);
+
+ return 0;
+}
+
+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.map_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);
+}
+
+/*
+ * 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;
+
+ btrfs_dev_replace_read_lock(dev_replace);
+ /* 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);
+ btrfs_dev_replace_read_unlock(dev_replace);
+}
+
+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);
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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;
+ btrfs_dev_replace_write_unlock(dev_replace);
+ goto leave;
+ case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
+ case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
+ 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;
+ break;
+ }
+ dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
+ dev_replace->time_stopped = ktime_get_real_seconds();
+ dev_replace->item_needs_writeback = 1;
+ btrfs_dev_replace_write_unlock(dev_replace);
+ 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,
+ "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);
+
+leave:
+ 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);
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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;
+ }
+
+ btrfs_dev_replace_write_unlock(dev_replace);
+ 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;
+
+ btrfs_dev_replace_write_lock(dev_replace);
+ 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:
+ btrfs_dev_replace_write_unlock(dev_replace);
+ 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'");
+ btrfs_dev_replace_write_unlock(dev_replace);
+ return 0;
+ }
+ btrfs_dev_replace_write_unlock(dev_replace);
+
+ /*
+ * 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 (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
+ 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);
+
+ clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
+ return 0;
+}
+
+int 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 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_dev_replace_read_lock(struct btrfs_dev_replace *dev_replace)
+{
+ read_lock(&dev_replace->lock);
+ atomic_inc(&dev_replace->read_locks);
+}
+
+void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace)
+{
+ ASSERT(atomic_read(&dev_replace->read_locks) > 0);
+ atomic_dec(&dev_replace->read_locks);
+ read_unlock(&dev_replace->lock);
+}
+
+void btrfs_dev_replace_write_lock(struct btrfs_dev_replace *dev_replace)
+{
+again:
+ wait_event(dev_replace->read_lock_wq,
+ atomic_read(&dev_replace->blocking_readers) == 0);
+ write_lock(&dev_replace->lock);
+ if (atomic_read(&dev_replace->blocking_readers)) {
+ write_unlock(&dev_replace->lock);
+ goto again;
+ }
+}
+
+void btrfs_dev_replace_write_unlock(struct btrfs_dev_replace *dev_replace)
+{
+ ASSERT(atomic_read(&dev_replace->blocking_readers) == 0);
+ write_unlock(&dev_replace->lock);
+}
+
+/* inc blocking cnt and release read lock */
+void btrfs_dev_replace_set_lock_blocking(
+ struct btrfs_dev_replace *dev_replace)
+{
+ /* only set blocking for read lock */
+ ASSERT(atomic_read(&dev_replace->read_locks) > 0);
+ atomic_inc(&dev_replace->blocking_readers);
+ read_unlock(&dev_replace->lock);
+}
+
+/* acquire read lock and dec blocking cnt */
+void btrfs_dev_replace_clear_lock_blocking(
+ struct btrfs_dev_replace *dev_replace)
+{
+ /* only set blocking for read lock */
+ ASSERT(atomic_read(&dev_replace->read_locks) > 0);
+ ASSERT(atomic_read(&dev_replace->blocking_readers) > 0);
+ read_lock(&dev_replace->lock);
+ /* Barrier implied by atomic_dec_and_test */
+ if (atomic_dec_and_test(&dev_replace->blocking_readers))
+ cond_wake_up_nomb(&dev_replace->read_lock_wq);
+}
+
+void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info)
+{
+ percpu_counter_inc(&fs_info->bio_counter);
+}
+
+void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
+{
+ percpu_counter_sub(&fs_info->bio_counter, amount);
+ cond_wake_up_nomb(&fs_info->replace_wait);
+}
+
+void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
+{
+ while (1) {
+ percpu_counter_inc(&fs_info->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->replace_wait,
+ !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
+ &fs_info->fs_state));
+ }
+}