Btrfs: add new sources for device replace code
This adds a new file to the sources together with the header file
and the changes to ioctl.h and ctree.h that are required by the
new C source file. Additionally, 4 new functions are added to
volume.c that deal with device creation and destruction.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
new file mode 100644
index 0000000..66dbc8d
--- /dev/null
+++ b/fs/btrfs/dev-replace.c
@@ -0,0 +1,856 @@
+/*
+ * 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_free_path(path);
+ 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;
+
+ printk_in_rcu(KERN_INFO
+ "btrfs: dev_replace from %s (devid %llu) to %s) started\n",
+ src_device->missing ? "<missing disk>" :
+ rcu_str_deref(src_device->name),
+ src_device->devid,
+ rcu_str_deref(tgt_device->name));
+
+ 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);
+ 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",
+ src_device->missing ? "<missing disk>" :
+ 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;
+ }
+
+ printk_in_rcu(KERN_INFO
+ "btrfs: dev_replace from %s (devid %llu) to %s) finished\n",
+ src_device->missing ? "<missing disk>" :
+ rcu_str_deref(src_device->name),
+ src_device->devid,
+ rcu_str_deref(tgt_device->name));
+ 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) {
+ ret = 0;
+ *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);
+ }
+}