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dev-replace.c
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// 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 "rcu-string.h"
#include "dev-replace.h"
#include "sysfs.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 contans 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 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_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_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->fs_devices,
src_devid, NULL, NULL, true);
dev_replace->tgtdev = btrfs_find_device(fs_info->fs_devices,
BTRFS_DEV_REPLACE_DEVID,
NULL, NULL, true);
/*
* 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);
}
sync_blockdev(bdev);
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);
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;
mutex_lock(&fs_info->fs_devices->device_list_mutex);
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 = 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_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);
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(eb);
out:
btrfs_free_path(path);
return ret;
}
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);
}
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;
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,
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);
up_write(&dev_replace->rwsem);
ret = btrfs_sysfs_add_devices_dir(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);
/* Commit dev_replace state and reserve 1 item for it. */
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);
}
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);
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, -1);
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_info->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_info->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;
/* 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 {
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,
rcu_str_deref(tgt_device->name), scrub_ret);
up_write(&dev_replace->rwsem);
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);
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++;
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_info->fs_devices->device_list_mutex);
/* replace the sysfs entry */
btrfs_sysfs_remove_devices_dir(fs_info->fs_devices, src_device);
btrfs_sysfs_update_devid(tgt_device);
btrfs_rm_dev_replace_free_srcdev(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;
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;
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 */
ret = btrfs_scrub_cancel(fs_info);
ASSERT(ret != -ENOTCONN);
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 (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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)