On Tue, Nov 06, 2012 at 05:38:33PM +0100, Stefan Behrens wrote:
> This adds a new file to the sources together with the header file
> and the changes to ioctl.h that are required by the new C source
> file.
>
> Signed-off-by: Stefan Behrens <sbehr...@giantdisaster.de>
> ---
> fs/btrfs/dev-replace.c | 843
> +++++++++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/dev-replace.h | 44 +++
> fs/btrfs/ioctl.h | 45 +++
> 3 files changed, 932 insertions(+)
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> new file mode 100644
> index 0000000..1d56163
> --- /dev/null
> +++ b/fs/btrfs/dev-replace.c
> @@ -0,0 +1,843 @@
> +/*
> + * Copyright (C) STRATO AG 2012. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License v2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; if not, write to the
> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
> + * Boston, MA 021110-1307, USA.
> + */
> +#include <linux/sched.h>
> +#include <linux/bio.h>
> +#include <linux/slab.h>
> +#include <linux/buffer_head.h>
> +#include <linux/blkdev.h>
> +#include <linux/random.h>
> +#include <linux/iocontext.h>
> +#include <linux/capability.h>
> +#include <linux/kthread.h>
> +#include <linux/math64.h>
> +#include <asm/div64.h>
> +#include "compat.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"
> +
> +static u64 btrfs_get_seconds_since_1970(void);
> +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_find_srcdev(struct btrfs_root *root, u64
> srcdevid,
> + char *srcdev_name,
> + struct btrfs_device **device);
> +static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
> +static int btrfs_dev_replace_kthread(void *data);
> +static int btrfs_dev_replace_continue_on_mount(struct btrfs_fs_info
> *fs_info);
> +
> +
> +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)) {
> + pr_warn("btrfs: dev_replace entry found has unexpected size,
> ignore entry\n");
> + 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(dev_root, DEGRADED)) {
> + ret = -EIO;
> + pr_warn("btrfs: cannot mount because device replace
> operation is ongoing and\n" "srcdev (devid %llu) is missing, need to run
> 'btrfs dev scan'?\n",
> + (unsigned long long)src_devid);
> + }
> + if (!dev_replace->tgtdev &&
> + !btrfs_test_opt(dev_root, DEGRADED)) {
> + ret = -EIO;
> + pr_warn("btrfs: cannot mount because device replace
> operation is ongoing and\n" "tgtdev (devid %llu) is missing, need to run
> btrfs dev scan?\n",
> + (unsigned long long)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->bytes_used =
> + dev_replace->srcdev->bytes_used;
> + }
> + dev_replace->tgtdev->is_tgtdev_for_dev_replace = 1;
> + btrfs_init_dev_replace_tgtdev_for_resume(fs_info,
> + dev_replace->tgtdev);
> + }
> + break;
> + }
> +
> +out:
> + if (path) {
> + btrfs_release_path(path);
> + btrfs_free_path(path);
btrfs_free_path(path) will do release for you :)
> + }
> + 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_lock(dev_replace);
> + if (!dev_replace->is_valid ||
> + !dev_replace->item_needs_writeback) {
> + btrfs_dev_replace_unlock(dev_replace);
> + return 0;
> + }
> + btrfs_dev_replace_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) {
> + pr_warn("btrfs: error %d while searching for dev_replace
> item!\n",
> + 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) {
> + pr_warn("btrfs: delete too small dev_replace item
> failed %d!\n",
> + 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) {
> + pr_warn("btrfs: insert dev_replace item failed %d!\n",
> + ret);
> + goto out;
> + }
> + }
> +
> + eb = path->nodes[0];
> + ptr = btrfs_item_ptr(eb, path->slots[0],
> + struct btrfs_dev_replace_item);
> +
> + btrfs_dev_replace_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_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 u64 btrfs_get_seconds_since_1970(void)
> +{
> + struct timespec t = CURRENT_TIME_SEC;
> +
> + return t.tv_sec;
> +}
> +
> +int btrfs_dev_replace_start(struct btrfs_root *root,
> + struct btrfs_ioctl_dev_replace_args *args)
> +{
> + struct btrfs_trans_handle *trans;
> + struct btrfs_fs_info *fs_info = root->fs_info;
> + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
> + int ret;
> + struct btrfs_device *tgt_device = NULL;
> + struct btrfs_device *src_device = NULL;
> +
> + 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;
> +
> + mutex_lock(&fs_info->volume_mutex);
> + ret = btrfs_init_dev_replace_tgtdev(root, args->start.tgtdev_name,
> + &tgt_device);
> + if (ret) {
> + pr_err("btrfs: target device %s is invalid!\n",
> + args->start.tgtdev_name);
> + mutex_unlock(&fs_info->volume_mutex);
> + return -EINVAL;
> + }
> +
> + ret = btrfs_dev_replace_find_srcdev(root, args->start.srcdevid,
> + args->start.srcdev_name,
> + &src_device);
> + mutex_unlock(&fs_info->volume_mutex);
> + if (ret) {
> + ret = -EINVAL;
> + goto leave_no_lock;
> + }
> +
> + if (tgt_device->total_bytes < src_device->total_bytes) {
> + pr_err("btrfs: target device is smaller than source device!\n");
> + ret = -EINVAL;
> + goto leave_no_lock;
> + }
> +
> + btrfs_dev_replace_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:
> + args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
> + goto leave;
> + }
> +
> + dev_replace->cont_reading_from_srcdev_mode =
> + args->start.cont_reading_from_srcdev_mode;
> + WARN_ON(!src_device);
> + dev_replace->srcdev = src_device;
> + WARN_ON(!tgt_device);
> + dev_replace->tgtdev = tgt_device;
> +
> + tgt_device->total_bytes = src_device->total_bytes;
> + tgt_device->disk_total_bytes = src_device->disk_total_bytes;
> + tgt_device->bytes_used = src_device->bytes_used;
> +
> + /*
> + * 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 = btrfs_get_seconds_since_1970();
> + 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;
> + args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
> + btrfs_dev_replace_unlock(dev_replace);
> +
> + btrfs_wait_ordered_extents(root, 0);
> +
> + /* force writing the updated state information to disk */
> + trans = btrfs_start_transaction(root, 0);
why a start_transaction here? Any reasons?
(same question also for some other places)
thanks,
liubo
> + if (IS_ERR(trans)) {
> + ret = PTR_ERR(trans);
> + btrfs_dev_replace_lock(dev_replace);
> + goto leave;
> + }
> +
> + ret = btrfs_commit_transaction(trans, root);
> + WARN_ON(ret);
> +
> + /* the disk copy procedure reuses the scrub code */
> + ret = btrfs_scrub_dev(fs_info, src_device->devid, 0,
> + src_device->total_bytes,
> + &dev_replace->scrub_progress, 0, 1);
> +
> + ret = btrfs_dev_replace_finishing(root->fs_info, ret);
> + WARN_ON(ret);
> +
> + return 0;
> +
> +leave:
> + dev_replace->srcdev = NULL;
> + dev_replace->tgtdev = NULL;
> + btrfs_dev_replace_unlock(dev_replace);
> +leave_no_lock:
> + if (tgt_device)
> + btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
> + return ret;
> +}
> +
> +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_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_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_unlock(dev_replace);
> +
> + /* 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);
> +
> + /*
> + * flush all outstanding I/O and inode extent mappings before the
> + * copy operation is declared as being finished
> + */
> + btrfs_start_delalloc_inodes(root, 0);
> + btrfs_wait_ordered_extents(root, 0);
> +
> + 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, root);
> + WARN_ON(ret);
> +
> + /* keep away write_all_supers() during the finishing procedure */
> + mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
> + btrfs_dev_replace_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 = btrfs_get_seconds_since_1970();
> + dev_replace->item_needs_writeback = 1;
> +
> + if (scrub_ret) {
> + printk_in_rcu(KERN_ERR
> + "btrfs: btrfs_scrub_dev(%s, %llu, %s) failed
> %d\n",
> + rcu_str_deref(src_device->name),
> + src_device->devid,
> + rcu_str_deref(tgt_device->name), scrub_ret);
> + btrfs_dev_replace_unlock(dev_replace);
> + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
> + if (tgt_device)
> + btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
> + mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
> +
> + return 0;
> + }
> +
> + tgt_device->is_tgtdev_for_dev_replace = 0;
> + tgt_device->devid = src_device->devid;
> + src_device->devid = BTRFS_DEV_REPLACE_DEVID;
> + tgt_device->bytes_used = src_device->bytes_used;
> + 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));
> + tgt_device->total_bytes = src_device->total_bytes;
> + tgt_device->disk_total_bytes = src_device->disk_total_bytes;
> + tgt_device->bytes_used = src_device->bytes_used;
> + if (fs_info->sb->s_bdev == src_device->bdev)
> + fs_info->sb->s_bdev = tgt_device->bdev;
> + if (fs_info->fs_devices->latest_bdev == src_device->bdev)
> + fs_info->fs_devices->latest_bdev = tgt_device->bdev;
> + list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
> +
> + btrfs_rm_dev_replace_srcdev(fs_info, src_device);
> + if (src_device->bdev) {
> + /* zero out the old super */
> + btrfs_scratch_superblock(src_device);
> + }
> + /*
> + * 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.
> + */
> + btrfs_dev_replace_unlock(dev_replace);
> + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
> +
> + /* write back the superblocks */
> + trans = btrfs_start_transaction(root, 0);
> + if (!IS_ERR(trans))
> + btrfs_commit_transaction(trans, root);
> +
> + 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 = (struct map_lookup *)em->bdev;
> + 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_find_srcdev(struct btrfs_root *root, u64
> srcdevid,
> + char *srcdev_name,
> + struct btrfs_device **device)
> +{
> + int ret;
> +
> + if (srcdevid) {
> + *device = btrfs_find_device(root->fs_info, srcdevid, NULL,
> + NULL);
> + if (!*device)
> + ret = -ENOENT;
> + } else {
> + ret = btrfs_find_device_missing_or_by_path(root, srcdev_name,
> + device);
> + }
> + 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_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);
> + switch (dev_replace->replace_state) {
> + case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
> + case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
> + args->status.progress_1000 = 0;
> + break;
> + case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
> + args->status.progress_1000 = 1000;
> + break;
> + case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
> + case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
> + args->status.progress_1000 = div64_u64(dev_replace->cursor_left,
> + div64_u64(dev_replace->srcdev->total_bytes, 1000));
> + break;
> + }
> + btrfs_dev_replace_unlock(dev_replace);
> +}
> +
> +int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info,
> + struct btrfs_ioctl_dev_replace_args *args)
> +{
> + args->result = __btrfs_dev_replace_cancel(fs_info);
> + return 0;
> +}
> +
> +static u64 __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_trans_handle *trans;
> + struct btrfs_root *root = fs_info->tree_root;
> + u64 result;
> + int ret;
> +
> + mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
> + btrfs_dev_replace_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_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;
> + dev_replace->tgtdev = NULL;
> + dev_replace->srcdev = NULL;
> + break;
> + }
> + dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
> + dev_replace->time_stopped = btrfs_get_seconds_since_1970();
> + dev_replace->item_needs_writeback = 1;
> + btrfs_dev_replace_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, root);
> + WARN_ON(ret);
> + if (tgt_device)
> + btrfs_destroy_dev_replace_tgtdev(fs_info, 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_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 = btrfs_get_seconds_since_1970();
> + dev_replace->item_needs_writeback = 1;
> + pr_info("btrfs: suspending dev_replace for unmount\n");
> + break;
> + }
> +
> + btrfs_dev_replace_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_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_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) {
> + pr_info("btrfs: cannot continue dev_replace, tgtdev is
> missing\n"
> + "btrfs: you may cancel the operation after 'mount -o
> degraded'\n");
> + btrfs_dev_replace_unlock(dev_replace);
> + return 0;
> + }
> + btrfs_dev_replace_unlock(dev_replace);
> +
> + WARN_ON(atomic_xchg(
> + &fs_info->mutually_exclusive_operation_running, 1));
> + task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
> + return PTR_RET(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;
> + struct btrfs_ioctl_dev_replace_args *status_args;
> + u64 progress;
> +
> + status_args = kzalloc(sizeof(*status_args), GFP_NOFS);
> + if (status_args) {
> + btrfs_dev_replace_status(fs_info, status_args);
> + progress = status_args->status.progress_1000;
> + kfree(status_args);
> + do_div(progress, 10);
> + printk_in_rcu(KERN_INFO
> + "btrfs: continuing dev_replace from %s (devid
> %llu) to %s @%u%%\n",
> + dev_replace->srcdev->missing ? "<missing disk>" :
> + rcu_str_deref(dev_replace->srcdev->name),
> + dev_replace->srcdev->devid,
> + dev_replace->tgtdev ?
> + rcu_str_deref(dev_replace->tgtdev->name) :
> + "<missing target disk>",
> + (unsigned int)progress);
> + }
> + btrfs_dev_replace_continue_on_mount(fs_info);
> + atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
> +
> + return 0;
> +}
> +
> +static int btrfs_dev_replace_continue_on_mount(struct btrfs_fs_info *fs_info)
> +{
> + struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
> + int ret;
> +
> + ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid,
> + dev_replace->committed_cursor_left,
> + dev_replace->srcdev->total_bytes,
> + &dev_replace->scrub_progress, 0, 1);
> + ret = btrfs_dev_replace_finishing(fs_info, ret);
> + WARN_ON(ret);
> + 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 cancelation is wanted.
> + */
> + break;
> + }
> + return 1;
> +}
> +
> +void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace)
> +{
> + /* the beginning is just an optimization for the typical case */
> + if (atomic_read(&dev_replace->nesting_level) == 0) {
> +acquire_lock:
> + /* this is not a nested case where the same thread
> + * is trying to acqurire the same lock twice */
> + mutex_lock(&dev_replace->lock);
> + mutex_lock(&dev_replace->lock_management_lock);
> + dev_replace->lock_owner = current->pid;
> + atomic_inc(&dev_replace->nesting_level);
> + mutex_unlock(&dev_replace->lock_management_lock);
> + return;
> + }
> +
> + mutex_lock(&dev_replace->lock_management_lock);
> + if (atomic_read(&dev_replace->nesting_level) > 0 &&
> + dev_replace->lock_owner == current->pid) {
> + WARN_ON(!mutex_is_locked(&dev_replace->lock));
> + atomic_inc(&dev_replace->nesting_level);
> + mutex_unlock(&dev_replace->lock_management_lock);
> + return;
> + }
> +
> + mutex_unlock(&dev_replace->lock_management_lock);
> + goto acquire_lock;
> +}
> +
> +void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace)
> +{
> + WARN_ON(!mutex_is_locked(&dev_replace->lock));
> + mutex_lock(&dev_replace->lock_management_lock);
> + WARN_ON(atomic_read(&dev_replace->nesting_level) < 1);
> + WARN_ON(dev_replace->lock_owner != current->pid);
> + atomic_dec(&dev_replace->nesting_level);
> + if (atomic_read(&dev_replace->nesting_level) == 0) {
> + dev_replace->lock_owner = 0;
> + mutex_unlock(&dev_replace->lock_management_lock);
> + mutex_unlock(&dev_replace->lock);
> + } else {
> + mutex_unlock(&dev_replace->lock_management_lock);
> + }
> +}
> diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
> new file mode 100644
> index 0000000..20035cb
> --- /dev/null
> +++ b/fs/btrfs/dev-replace.h
> @@ -0,0 +1,44 @@
> +/*
> + * Copyright (C) STRATO AG 2012. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public
> + * License v2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public
> + * License along with this program; if not, write to the
> + * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
> + * Boston, MA 021110-1307, USA.
> + */
> +
> +#if !defined(__BTRFS_DEV_REPLACE__)
> +#define __BTRFS_DEV_REPLACE__
> +
> +struct btrfs_ioctl_dev_replace_args;
> +
> +int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info);
> +int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
> + struct btrfs_fs_info *fs_info);
> +void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info);
> +int btrfs_dev_replace_start(struct btrfs_root *root,
> + struct btrfs_ioctl_dev_replace_args *args);
> +void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
> + struct btrfs_ioctl_dev_replace_args *args);
> +int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info,
> + struct btrfs_ioctl_dev_replace_args *args);
> +void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info);
> +int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info);
> +int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
> +void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace);
> +void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace);
> +
> +static inline void btrfs_dev_replace_stats_inc(atomic64_t *stat_value)
> +{
> + atomic64_inc(stat_value);
> +}
> +#endif
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 731e287..62006ba 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -123,6 +123,48 @@ struct btrfs_ioctl_scrub_args {
> __u64 unused[(1024-32-sizeof(struct btrfs_scrub_progress))/8];
> };
>
> +#define BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS 0
> +#define BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID 1
> +struct btrfs_ioctl_dev_replace_start_params {
> + __u64 srcdevid; /* in, if 0, use srcdev_name instead */
> + __u8 srcdev_name[BTRFS_PATH_NAME_MAX + 1]; /* in */
> + __u8 tgtdev_name[BTRFS_PATH_NAME_MAX + 1]; /* in */
> + __u64 cont_reading_from_srcdev_mode; /* in, see #define
> + * above */
> +};
> +
> +#define BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED 0
> +#define BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED 1
> +#define BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED 2
> +#define BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED 3
> +#define BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED 4
> +struct btrfs_ioctl_dev_replace_status_params {
> + __u64 replace_state; /* out, see #define above */
> + __u64 progress_1000; /* out, 0 <= x <= 1000 */
> + __u64 time_started; /* out, seconds since 1-Jan-1970 */
> + __u64 time_stopped; /* out, seconds since 1-Jan-1970 */
> + __u64 num_write_errors; /* out */
> + __u64 num_uncorrectable_read_errors; /* out */
> +};
> +
> +#define BTRFS_IOCTL_DEV_REPLACE_CMD_START 0
> +#define BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS 1
> +#define BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL 2
> +#define BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR 0
> +#define BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED 1
> +#define BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED 2
> +struct btrfs_ioctl_dev_replace_args {
> + __u64 cmd; /* in */
> + __u64 result; /* out */
> +
> + union {
> + struct btrfs_ioctl_dev_replace_start_params start;
> + struct btrfs_ioctl_dev_replace_status_params status;
> + }; /* in/out */
> +
> + __u64 spare[64];
> +};
> +
> #define BTRFS_DEVICE_PATH_NAME_MAX 1024
> struct btrfs_ioctl_dev_info_args {
> __u64 devid; /* in/out */
> @@ -453,4 +495,7 @@ struct btrfs_ioctl_send_args {
> struct btrfs_ioctl_qgroup_limit_args)
> #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
> struct btrfs_ioctl_get_dev_stats)
> +#define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \
> + struct btrfs_ioctl_dev_replace_args)
> +
> #endif
> --
> 1.8.0
>
> --
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