Merge branch 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason...
[linux-2.6-block.git] / fs / btrfs / volumes.c
index 0d7d635d8bfbea68f1053d1d1830a3a8908c299e..3c3c69c0eee41494d751b2638d20cf6bf0811ca1 100644 (file)
@@ -134,9 +134,9 @@ const int btrfs_raid_mindev_error[BTRFS_NR_RAID_TYPES] = {
 };
 
 static int init_first_rw_device(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *root,
+                               struct btrfs_fs_info *fs_info,
                                struct btrfs_device *device);
-static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
+static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info);
 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
@@ -343,9 +343,9 @@ static void requeue_list(struct btrfs_pending_bios *pending_bios,
  */
 static noinline void run_scheduled_bios(struct btrfs_device *device)
 {
+       struct btrfs_fs_info *fs_info = device->fs_info;
        struct bio *pending;
        struct backing_dev_info *bdi;
-       struct btrfs_fs_info *fs_info;
        struct btrfs_pending_bios *pending_bios;
        struct bio *tail;
        struct bio *cur;
@@ -367,7 +367,6 @@ static noinline void run_scheduled_bios(struct btrfs_device *device)
        blk_start_plug(&plug);
 
        bdi = blk_get_backing_dev_info(device->bdev);
-       fs_info = device->dev_root->fs_info;
        limit = btrfs_async_submit_limit(fs_info);
        limit = limit * 2 / 3;
 
@@ -1179,7 +1178,7 @@ int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
                                   u64 end, u64 *length)
 {
        struct btrfs_key key;
-       struct btrfs_root *root = device->dev_root;
+       struct btrfs_root *root = device->fs_info->dev_root;
        struct btrfs_dev_extent *dev_extent;
        struct btrfs_path *path;
        u64 extent_end;
@@ -1262,7 +1261,7 @@ static int contains_pending_extent(struct btrfs_transaction *transaction,
                                   struct btrfs_device *device,
                                   u64 *start, u64 len)
 {
-       struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
+       struct btrfs_fs_info *fs_info = device->fs_info;
        struct extent_map *em;
        struct list_head *search_list = &fs_info->pinned_chunks;
        int ret = 0;
@@ -1338,8 +1337,9 @@ int find_free_dev_extent_start(struct btrfs_transaction *transaction,
                               struct btrfs_device *device, u64 num_bytes,
                               u64 search_start, u64 *start, u64 *len)
 {
+       struct btrfs_fs_info *fs_info = device->fs_info;
+       struct btrfs_root *root = fs_info->dev_root;
        struct btrfs_key key;
-       struct btrfs_root *root = device->dev_root;
        struct btrfs_dev_extent *dev_extent;
        struct btrfs_path *path;
        u64 hole_size;
@@ -1357,7 +1357,7 @@ int find_free_dev_extent_start(struct btrfs_transaction *transaction,
         * used by the boot loader (grub for example), so we make sure to start
         * at an offset of at least 1MB.
         */
-       min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
+       min_search_start = max(fs_info->alloc_start, 1024ull * 1024);
        search_start = max(search_start, min_search_start);
 
        path = btrfs_alloc_path();
@@ -1508,9 +1508,10 @@ static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
                          struct btrfs_device *device,
                          u64 start, u64 *dev_extent_len)
 {
+       struct btrfs_fs_info *fs_info = device->fs_info;
+       struct btrfs_root *root = fs_info->dev_root;
        int ret;
        struct btrfs_path *path;
-       struct btrfs_root *root = device->dev_root;
        struct btrfs_key key;
        struct btrfs_key found_key;
        struct extent_buffer *leaf = NULL;
@@ -1544,7 +1545,7 @@ again:
                extent = btrfs_item_ptr(leaf, path->slots[0],
                                        struct btrfs_dev_extent);
        } else {
-               btrfs_handle_fs_error(root->fs_info, ret, "Slot search failed");
+               btrfs_handle_fs_error(fs_info, ret, "Slot search failed");
                goto out;
        }
 
@@ -1552,8 +1553,8 @@ again:
 
        ret = btrfs_del_item(trans, root, path);
        if (ret) {
-               btrfs_handle_fs_error(root->fs_info, ret,
-                           "Failed to remove dev extent item");
+               btrfs_handle_fs_error(fs_info, ret,
+                                     "Failed to remove dev extent item");
        } else {
                set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
        }
@@ -1569,7 +1570,8 @@ static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 {
        int ret;
        struct btrfs_path *path;
-       struct btrfs_root *root = device->dev_root;
+       struct btrfs_fs_info *fs_info = device->fs_info;
+       struct btrfs_root *root = fs_info->dev_root;
        struct btrfs_dev_extent *extent;
        struct extent_buffer *leaf;
        struct btrfs_key key;
@@ -1595,8 +1597,7 @@ static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
        btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
        btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 
-       write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
-                   btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
+       write_extent_buffer_chunk_tree_uuid(leaf, fs_info->chunk_tree_uuid);
 
        btrfs_set_dev_extent_length(leaf, extent, num_bytes);
        btrfs_mark_buffer_dirty(leaf);
@@ -1667,9 +1668,10 @@ error:
  * the btrfs_device struct should be fully filled in
  */
 static int btrfs_add_device(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root,
+                           struct btrfs_fs_info *fs_info,
                            struct btrfs_device *device)
 {
+       struct btrfs_root *root = fs_info->chunk_root;
        int ret;
        struct btrfs_path *path;
        struct btrfs_dev_item *dev_item;
@@ -1677,8 +1679,6 @@ static int btrfs_add_device(struct btrfs_trans_handle *trans,
        struct btrfs_key key;
        unsigned long ptr;
 
-       root = root->fs_info->chunk_root;
-
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
@@ -1713,7 +1713,7 @@ static int btrfs_add_device(struct btrfs_trans_handle *trans,
        ptr = btrfs_device_uuid(dev_item);
        write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
        ptr = btrfs_device_fsid(dev_item);
-       write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
+       write_extent_buffer(leaf, fs_info->fsid, ptr, BTRFS_UUID_SIZE);
        btrfs_mark_buffer_dirty(leaf);
 
        ret = 0;
@@ -1737,16 +1737,15 @@ static void update_dev_time(char *path_name)
        filp_close(filp, NULL);
 }
 
-static int btrfs_rm_dev_item(struct btrfs_root *root,
+static int btrfs_rm_dev_item(struct btrfs_fs_info *fs_info,
                             struct btrfs_device *device)
 {
+       struct btrfs_root *root = fs_info->chunk_root;
        int ret;
        struct btrfs_path *path;
        struct btrfs_key key;
        struct btrfs_trans_handle *trans;
 
-       root = root->fs_info->chunk_root;
-
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
@@ -1774,7 +1773,7 @@ static int btrfs_rm_dev_item(struct btrfs_root *root,
                goto out;
 out:
        btrfs_free_path(path);
-       btrfs_commit_transaction(trans, root);
+       btrfs_commit_transaction(trans);
        return ret;
 }
 
@@ -1853,7 +1852,7 @@ void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
                fs_info->fs_devices->latest_bdev = next_device->bdev;
 }
 
-int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
+int btrfs_rm_device(struct btrfs_fs_info *fs_info, char *device_path, u64 devid)
 {
        struct btrfs_device *device;
        struct btrfs_fs_devices *cur_devices;
@@ -1863,20 +1862,20 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
 
        mutex_lock(&uuid_mutex);
 
-       num_devices = root->fs_info->fs_devices->num_devices;
-       btrfs_dev_replace_lock(&root->fs_info->dev_replace, 0);
-       if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
+       num_devices = fs_info->fs_devices->num_devices;
+       btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
+       if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
                WARN_ON(num_devices < 1);
                num_devices--;
        }
-       btrfs_dev_replace_unlock(&root->fs_info->dev_replace, 0);
+       btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
 
-       ret = btrfs_check_raid_min_devices(root->fs_info, num_devices - 1);
+       ret = btrfs_check_raid_min_devices(fs_info, num_devices - 1);
        if (ret)
                goto out;
 
-       ret = btrfs_find_device_by_devspec(root, devid, device_path,
-                               &device);
+       ret = btrfs_find_device_by_devspec(fs_info, devid, device_path,
+                                          &device);
        if (ret)
                goto out;
 
@@ -1885,16 +1884,16 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
                goto out;
        }
 
-       if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
+       if (device->writeable && fs_info->fs_devices->rw_devices == 1) {
                ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
                goto out;
        }
 
        if (device->writeable) {
-               lock_chunks(root);
+               mutex_lock(&fs_info->chunk_mutex);
                list_del_init(&device->dev_alloc_list);
                device->fs_devices->rw_devices--;
-               unlock_chunks(root);
+               mutex_unlock(&fs_info->chunk_mutex);
                clear_super = true;
        }
 
@@ -1909,12 +1908,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
         * counter although write_all_supers() is not locked out. This
         * could give a filesystem state which requires a degraded mount.
         */
-       ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
+       ret = btrfs_rm_dev_item(fs_info, device);
        if (ret)
                goto error_undo;
 
        device->in_fs_metadata = 0;
-       btrfs_scrub_cancel_dev(root->fs_info, device);
+       btrfs_scrub_cancel_dev(fs_info, device);
 
        /*
         * the device list mutex makes sure that we don't change
@@ -1927,7 +1926,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
         */
 
        cur_devices = device->fs_devices;
-       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        list_del_rcu(&device->dev_list);
 
        device->fs_devices->num_devices--;
@@ -1936,17 +1935,17 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
        if (device->missing)
                device->fs_devices->missing_devices--;
 
-       btrfs_assign_next_active_device(root->fs_info, device, NULL);
+       btrfs_assign_next_active_device(fs_info, device, NULL);
 
        if (device->bdev) {
                device->fs_devices->open_devices--;
                /* remove sysfs entry */
-               btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
+               btrfs_sysfs_rm_device_link(fs_info->fs_devices, device);
        }
 
-       num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
-       btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
-       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+       num_devices = btrfs_super_num_devices(fs_info->super_copy) - 1;
+       btrfs_set_super_num_devices(fs_info->super_copy, num_devices);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
        /*
         * at this point, the device is zero sized and detached from
@@ -1961,7 +1960,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
 
        if (cur_devices->open_devices == 0) {
                struct btrfs_fs_devices *fs_devices;
-               fs_devices = root->fs_info->fs_devices;
+               fs_devices = fs_info->fs_devices;
                while (fs_devices) {
                        if (fs_devices->seed == cur_devices) {
                                fs_devices->seed = cur_devices->seed;
@@ -1974,8 +1973,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
                free_fs_devices(cur_devices);
        }
 
-       root->fs_info->num_tolerated_disk_barrier_failures =
-               btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
+       fs_info->num_tolerated_disk_barrier_failures =
+               btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
 
 out:
        mutex_unlock(&uuid_mutex);
@@ -1983,11 +1982,11 @@ out:
 
 error_undo:
        if (device->writeable) {
-               lock_chunks(root);
+               mutex_lock(&fs_info->chunk_mutex);
                list_add(&device->dev_alloc_list,
-                        &root->fs_info->fs_devices->alloc_list);
+                        &fs_info->fs_devices->alloc_list);
                device->fs_devices->rw_devices++;
-               unlock_chunks(root);
+               mutex_unlock(&fs_info->chunk_mutex);
        }
        goto out;
 }
@@ -2092,7 +2091,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
        call_rcu(&tgtdev->rcu, free_device);
 }
 
-static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
+static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
+                                    char *device_path,
                                     struct btrfs_device **device)
 {
        int ret = 0;
@@ -2104,14 +2104,13 @@ static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
 
        *device = NULL;
        ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
-                                   root->fs_info->bdev_holder, 0, &bdev, &bh);
+                                   fs_info->bdev_holder, 0, &bdev, &bh);
        if (ret)
                return ret;
        disk_super = (struct btrfs_super_block *)bh->b_data;
        devid = btrfs_stack_device_id(&disk_super->dev_item);
        dev_uuid = disk_super->dev_item.uuid;
-       *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
-                                   disk_super->fsid);
+       *device = btrfs_find_device(fs_info, devid, dev_uuid, disk_super->fsid);
        brelse(bh);
        if (!*device)
                ret = -ENOENT;
@@ -2119,7 +2118,7 @@ static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
        return ret;
 }
 
-int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
+int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
                                         char *device_path,
                                         struct btrfs_device **device)
 {
@@ -2128,7 +2127,7 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
                struct list_head *devices;
                struct btrfs_device *tmp;
 
-               devices = &root->fs_info->fs_devices->devices;
+               devices = &fs_info->fs_devices->devices;
                /*
                 * It is safe to read the devices since the volume_mutex
                 * is held by the caller.
@@ -2145,30 +2144,28 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
 
                return 0;
        } else {
-               return btrfs_find_device_by_path(root, device_path, device);
+               return btrfs_find_device_by_path(fs_info, device_path, device);
        }
 }
 
 /*
  * Lookup a device given by device id, or the path if the id is 0.
  */
-int btrfs_find_device_by_devspec(struct btrfs_root *root, u64 devid,
-                                        char *devpath,
-                                        struct btrfs_device **device)
+int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
+                                char *devpath, struct btrfs_device **device)
 {
        int ret;
 
        if (devid) {
                ret = 0;
-               *device = btrfs_find_device(root->fs_info, devid, NULL,
-                                           NULL);
+               *device = btrfs_find_device(fs_info, devid, NULL, NULL);
                if (!*device)
                        ret = -ENOENT;
        } else {
                if (!devpath || !devpath[0])
                        return -EINVAL;
 
-               ret = btrfs_find_device_missing_or_by_path(root, devpath,
+               ret = btrfs_find_device_missing_or_by_path(fs_info, devpath,
                                                           device);
        }
        return ret;
@@ -2177,12 +2174,12 @@ int btrfs_find_device_by_devspec(struct btrfs_root *root, u64 devid,
 /*
  * does all the dirty work required for changing file system's UUID.
  */
-static int btrfs_prepare_sprout(struct btrfs_root *root)
+static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info)
 {
-       struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+       struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
        struct btrfs_fs_devices *old_devices;
        struct btrfs_fs_devices *seed_devices;
-       struct btrfs_super_block *disk_super = root->fs_info->super_copy;
+       struct btrfs_super_block *disk_super = fs_info->super_copy;
        struct btrfs_device *device;
        u64 super_flags;
 
@@ -2208,15 +2205,15 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
        INIT_LIST_HEAD(&seed_devices->alloc_list);
        mutex_init(&seed_devices->device_list_mutex);
 
-       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
                              synchronize_rcu);
        list_for_each_entry(device, &seed_devices->devices, dev_list)
                device->fs_devices = seed_devices;
 
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
        list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
 
        fs_devices->seeding = 0;
        fs_devices->num_devices = 0;
@@ -2226,9 +2223,9 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
        fs_devices->seed = seed_devices;
 
        generate_random_uuid(fs_devices->fsid);
-       memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
+       memcpy(fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
        memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
-       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
        super_flags = btrfs_super_flags(disk_super) &
                      ~BTRFS_SUPER_FLAG_SEEDING;
@@ -2241,8 +2238,9 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
  * Store the expected generation for seed devices in device items.
  */
 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
-                              struct btrfs_root *root)
+                              struct btrfs_fs_info *fs_info)
 {
+       struct btrfs_root *root = fs_info->chunk_root;
        struct btrfs_path *path;
        struct extent_buffer *leaf;
        struct btrfs_dev_item *dev_item;
@@ -2257,7 +2255,6 @@ static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
        if (!path)
                return -ENOMEM;
 
-       root = root->fs_info->chunk_root;
        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
        key.offset = 0;
        key.type = BTRFS_DEV_ITEM_KEY;
@@ -2293,8 +2290,7 @@ next_slot:
                                   BTRFS_UUID_SIZE);
                read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
                                   BTRFS_UUID_SIZE);
-               device = btrfs_find_device(root->fs_info, devid, dev_uuid,
-                                          fs_uuid);
+               device = btrfs_find_device(fs_info, devid, dev_uuid, fs_uuid);
                BUG_ON(!device); /* Logic error */
 
                if (device->fs_devices->seeding) {
@@ -2312,28 +2308,29 @@ error:
        return ret;
 }
 
-int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
+int btrfs_init_new_device(struct btrfs_fs_info *fs_info, char *device_path)
 {
+       struct btrfs_root *root = fs_info->dev_root;
        struct request_queue *q;
        struct btrfs_trans_handle *trans;
        struct btrfs_device *device;
        struct block_device *bdev;
        struct list_head *devices;
-       struct super_block *sb = root->fs_info->sb;
+       struct super_block *sb = fs_info->sb;
        struct rcu_string *name;
        u64 tmp;
        int seeding_dev = 0;
        int ret = 0;
 
-       if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
+       if ((sb->s_flags & MS_RDONLY) && !fs_info->fs_devices->seeding)
                return -EROFS;
 
        bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
-                                 root->fs_info->bdev_holder);
+                                 fs_info->bdev_holder);
        if (IS_ERR(bdev))
                return PTR_ERR(bdev);
 
-       if (root->fs_info->fs_devices->seeding) {
+       if (fs_info->fs_devices->seeding) {
                seeding_dev = 1;
                down_write(&sb->s_umount);
                mutex_lock(&uuid_mutex);
@@ -2341,20 +2338,20 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
        filemap_write_and_wait(bdev->bd_inode->i_mapping);
 
-       devices = &root->fs_info->fs_devices->devices;
+       devices = &fs_info->fs_devices->devices;
 
-       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        list_for_each_entry(device, devices, dev_list) {
                if (device->bdev == bdev) {
                        ret = -EEXIST;
                        mutex_unlock(
-                               &root->fs_info->fs_devices->device_list_mutex);
+                               &fs_info->fs_devices->device_list_mutex);
                        goto error;
                }
        }
-       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
-       device = btrfs_alloc_device(root->fs_info, NULL, NULL);
+       device = btrfs_alloc_device(fs_info, NULL, NULL);
        if (IS_ERR(device)) {
                /* we can safely leave the fs_devices entry around */
                ret = PTR_ERR(device);
@@ -2382,13 +2379,13 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                device->can_discard = 1;
        device->writeable = 1;
        device->generation = trans->transid;
-       device->io_width = root->sectorsize;
-       device->io_align = root->sectorsize;
-       device->sector_size = root->sectorsize;
+       device->io_width = fs_info->sectorsize;
+       device->io_align = fs_info->sectorsize;
+       device->sector_size = fs_info->sectorsize;
        device->total_bytes = i_size_read(bdev->bd_inode);
        device->disk_total_bytes = device->total_bytes;
        device->commit_total_bytes = device->total_bytes;
-       device->dev_root = root->fs_info->dev_root;
+       device->fs_info = fs_info;
        device->bdev = bdev;
        device->in_fs_metadata = 1;
        device->is_tgtdev_for_dev_replace = 0;
@@ -2398,61 +2395,60 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
        if (seeding_dev) {
                sb->s_flags &= ~MS_RDONLY;
-               ret = btrfs_prepare_sprout(root);
+               ret = btrfs_prepare_sprout(fs_info);
                BUG_ON(ret); /* -ENOMEM */
        }
 
-       device->fs_devices = root->fs_info->fs_devices;
+       device->fs_devices = fs_info->fs_devices;
 
-       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
-       lock_chunks(root);
-       list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->chunk_mutex);
+       list_add_rcu(&device->dev_list, &fs_info->fs_devices->devices);
        list_add(&device->dev_alloc_list,
-                &root->fs_info->fs_devices->alloc_list);
-       root->fs_info->fs_devices->num_devices++;
-       root->fs_info->fs_devices->open_devices++;
-       root->fs_info->fs_devices->rw_devices++;
-       root->fs_info->fs_devices->total_devices++;
-       root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
+                &fs_info->fs_devices->alloc_list);
+       fs_info->fs_devices->num_devices++;
+       fs_info->fs_devices->open_devices++;
+       fs_info->fs_devices->rw_devices++;
+       fs_info->fs_devices->total_devices++;
+       fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
-       spin_lock(&root->fs_info->free_chunk_lock);
-       root->fs_info->free_chunk_space += device->total_bytes;
-       spin_unlock(&root->fs_info->free_chunk_lock);
+       spin_lock(&fs_info->free_chunk_lock);
+       fs_info->free_chunk_space += device->total_bytes;
+       spin_unlock(&fs_info->free_chunk_lock);
 
        if (!blk_queue_nonrot(bdev_get_queue(bdev)))
-               root->fs_info->fs_devices->rotating = 1;
+               fs_info->fs_devices->rotating = 1;
 
-       tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
-       btrfs_set_super_total_bytes(root->fs_info->super_copy,
+       tmp = btrfs_super_total_bytes(fs_info->super_copy);
+       btrfs_set_super_total_bytes(fs_info->super_copy,
                                    tmp + device->total_bytes);
 
-       tmp = btrfs_super_num_devices(root->fs_info->super_copy);
-       btrfs_set_super_num_devices(root->fs_info->super_copy,
-                                   tmp + 1);
+       tmp = btrfs_super_num_devices(fs_info->super_copy);
+       btrfs_set_super_num_devices(fs_info->super_copy, tmp + 1);
 
        /* add sysfs device entry */
-       btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
+       btrfs_sysfs_add_device_link(fs_info->fs_devices, device);
 
        /*
         * we've got more storage, clear any full flags on the space
         * infos
         */
-       btrfs_clear_space_info_full(root->fs_info);
+       btrfs_clear_space_info_full(fs_info);
 
-       unlock_chunks(root);
-       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_info->chunk_mutex);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
        if (seeding_dev) {
-               lock_chunks(root);
-               ret = init_first_rw_device(trans, root, device);
-               unlock_chunks(root);
+               mutex_lock(&fs_info->chunk_mutex);
+               ret = init_first_rw_device(trans, fs_info, device);
+               mutex_unlock(&fs_info->chunk_mutex);
                if (ret) {
                        btrfs_abort_transaction(trans, ret);
                        goto error_trans;
                }
        }
 
-       ret = btrfs_add_device(trans, root, device);
+       ret = btrfs_add_device(trans, fs_info, device);
        if (ret) {
                btrfs_abort_transaction(trans, ret);
                goto error_trans;
@@ -2461,7 +2457,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        if (seeding_dev) {
                char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
 
-               ret = btrfs_finish_sprout(trans, root);
+               ret = btrfs_finish_sprout(trans, fs_info);
                if (ret) {
                        btrfs_abort_transaction(trans, ret);
                        goto error_trans;
@@ -2471,16 +2467,15 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                 * so rename the fsid on the sysfs
                 */
                snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
-                                               root->fs_info->fsid);
-               if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
-                                                               fsid_buf))
-                       btrfs_warn(root->fs_info,
-                               "sysfs: failed to create fsid for sprout");
+                                               fs_info->fsid);
+               if (kobject_rename(&fs_info->fs_devices->fsid_kobj, fsid_buf))
+                       btrfs_warn(fs_info,
+                                  "sysfs: failed to create fsid for sprout");
        }
 
-       root->fs_info->num_tolerated_disk_barrier_failures =
-               btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
-       ret = btrfs_commit_transaction(trans, root);
+       fs_info->num_tolerated_disk_barrier_failures =
+               btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
+       ret = btrfs_commit_transaction(trans);
 
        if (seeding_dev) {
                mutex_unlock(&uuid_mutex);
@@ -2489,9 +2484,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                if (ret) /* transaction commit */
                        return ret;
 
-               ret = btrfs_relocate_sys_chunks(root);
+               ret = btrfs_relocate_sys_chunks(fs_info);
                if (ret < 0)
-                       btrfs_handle_fs_error(root->fs_info, ret,
+                       btrfs_handle_fs_error(fs_info, ret,
                                    "Failed to relocate sys chunks after device initialization. This can be fixed using the \"btrfs balance\" command.");
                trans = btrfs_attach_transaction(root);
                if (IS_ERR(trans)) {
@@ -2499,7 +2494,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
                                return 0;
                        return PTR_ERR(trans);
                }
-               ret = btrfs_commit_transaction(trans, root);
+               ret = btrfs_commit_transaction(trans);
        }
 
        /* Update ctime/mtime for libblkid */
@@ -2507,9 +2502,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
        return ret;
 
 error_trans:
-       btrfs_end_transaction(trans, root);
+       btrfs_end_transaction(trans);
        rcu_string_free(device->name);
-       btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
+       btrfs_sysfs_rm_device_link(fs_info->fs_devices, device);
        kfree(device);
 error:
        blkdev_put(bdev, FMODE_EXCL);
@@ -2520,14 +2515,14 @@ error:
        return ret;
 }
 
-int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
+int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
+                                 char *device_path,
                                  struct btrfs_device *srcdev,
                                  struct btrfs_device **device_out)
 {
        struct request_queue *q;
        struct btrfs_device *device;
        struct block_device *bdev;
-       struct btrfs_fs_info *fs_info = root->fs_info;
        struct list_head *devices;
        struct rcu_string *name;
        u64 devid = BTRFS_DEV_REPLACE_DEVID;
@@ -2585,19 +2580,19 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
        q = bdev_get_queue(bdev);
        if (blk_queue_discard(q))
                device->can_discard = 1;
-       mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        device->writeable = 1;
        device->generation = 0;
-       device->io_width = root->sectorsize;
-       device->io_align = root->sectorsize;
-       device->sector_size = root->sectorsize;
+       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);
        ASSERT(list_empty(&srcdev->resized_list));
        device->commit_total_bytes = srcdev->commit_total_bytes;
        device->commit_bytes_used = device->bytes_used;
-       device->dev_root = fs_info->dev_root;
+       device->fs_info = fs_info;
        device->bdev = bdev;
        device->in_fs_metadata = 1;
        device->is_tgtdev_for_dev_replace = 1;
@@ -2608,7 +2603,7 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
        list_add(&device->dev_list, &fs_info->fs_devices->devices);
        fs_info->fs_devices->num_devices++;
        fs_info->fs_devices->open_devices++;
-       mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
        *device_out = device;
        return ret;
@@ -2621,11 +2616,13 @@ error:
 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
                                              struct btrfs_device *tgtdev)
 {
+       u32 sectorsize = fs_info->sectorsize;
+
        WARN_ON(fs_info->fs_devices->rw_devices == 0);
-       tgtdev->io_width = fs_info->dev_root->sectorsize;
-       tgtdev->io_align = fs_info->dev_root->sectorsize;
-       tgtdev->sector_size = fs_info->dev_root->sectorsize;
-       tgtdev->dev_root = fs_info->dev_root;
+       tgtdev->io_width = sectorsize;
+       tgtdev->io_align = sectorsize;
+       tgtdev->sector_size = sectorsize;
+       tgtdev->fs_info = fs_info;
        tgtdev->in_fs_metadata = 1;
 }
 
@@ -2634,13 +2631,11 @@ static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
 {
        int ret;
        struct btrfs_path *path;
-       struct btrfs_root *root;
+       struct btrfs_root *root = device->fs_info->chunk_root;
        struct btrfs_dev_item *dev_item;
        struct extent_buffer *leaf;
        struct btrfs_key key;
 
-       root = device->dev_root->fs_info->chunk_root;
-
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
@@ -2680,8 +2675,8 @@ out:
 int btrfs_grow_device(struct btrfs_trans_handle *trans,
                      struct btrfs_device *device, u64 new_size)
 {
-       struct btrfs_super_block *super_copy =
-               device->dev_root->fs_info->super_copy;
+       struct btrfs_fs_info *fs_info = device->fs_info;
+       struct btrfs_super_block *super_copy = fs_info->super_copy;
        struct btrfs_fs_devices *fs_devices;
        u64 old_total;
        u64 diff;
@@ -2689,41 +2684,41 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans,
        if (!device->writeable)
                return -EACCES;
 
-       lock_chunks(device->dev_root);
+       mutex_lock(&fs_info->chunk_mutex);
        old_total = btrfs_super_total_bytes(super_copy);
        diff = new_size - device->total_bytes;
 
        if (new_size <= device->total_bytes ||
            device->is_tgtdev_for_dev_replace) {
-               unlock_chunks(device->dev_root);
+               mutex_unlock(&fs_info->chunk_mutex);
                return -EINVAL;
        }
 
-       fs_devices = device->dev_root->fs_info->fs_devices;
+       fs_devices = fs_info->fs_devices;
 
        btrfs_set_super_total_bytes(super_copy, old_total + diff);
        device->fs_devices->total_rw_bytes += diff;
 
        btrfs_device_set_total_bytes(device, new_size);
        btrfs_device_set_disk_total_bytes(device, new_size);
-       btrfs_clear_space_info_full(device->dev_root->fs_info);
+       btrfs_clear_space_info_full(device->fs_info);
        if (list_empty(&device->resized_list))
                list_add_tail(&device->resized_list,
                              &fs_devices->resized_devices);
-       unlock_chunks(device->dev_root);
+       mutex_unlock(&fs_info->chunk_mutex);
 
        return btrfs_update_device(trans, device);
 }
 
 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root, u64 chunk_objectid,
+                           struct btrfs_fs_info *fs_info, u64 chunk_objectid,
                            u64 chunk_offset)
 {
+       struct btrfs_root *root = fs_info->chunk_root;
        int ret;
        struct btrfs_path *path;
        struct btrfs_key key;
 
-       root = root->fs_info->chunk_root;
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
@@ -2736,25 +2731,25 @@ static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
        if (ret < 0)
                goto out;
        else if (ret > 0) { /* Logic error or corruption */
-               btrfs_handle_fs_error(root->fs_info, -ENOENT,
-                           "Failed lookup while freeing chunk.");
+               btrfs_handle_fs_error(fs_info, -ENOENT,
+                                     "Failed lookup while freeing chunk.");
                ret = -ENOENT;
                goto out;
        }
 
        ret = btrfs_del_item(trans, root, path);
        if (ret < 0)
-               btrfs_handle_fs_error(root->fs_info, ret,
-                           "Failed to delete chunk item.");
+               btrfs_handle_fs_error(fs_info, ret,
+                                     "Failed to delete chunk item.");
 out:
        btrfs_free_path(path);
        return ret;
 }
 
-static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
-                       chunk_offset)
+static int btrfs_del_sys_chunk(struct btrfs_fs_info *fs_info,
+                              u64 chunk_objectid, u64 chunk_offset)
 {
-       struct btrfs_super_block *super_copy = root->fs_info->super_copy;
+       struct btrfs_super_block *super_copy = fs_info->super_copy;
        struct btrfs_disk_key *disk_key;
        struct btrfs_chunk *chunk;
        u8 *ptr;
@@ -2765,7 +2760,7 @@ static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
        u32 cur;
        struct btrfs_key key;
 
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
        array_size = btrfs_super_sys_array_size(super_copy);
 
        ptr = super_copy->sys_chunk_array;
@@ -2795,25 +2790,22 @@ static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
                        cur += len;
                }
        }
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
        return ret;
 }
 
 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
-                      struct btrfs_root *root, u64 chunk_offset)
+                      struct btrfs_fs_info *fs_info, u64 chunk_offset)
 {
        struct extent_map_tree *em_tree;
        struct extent_map *em;
-       struct btrfs_root *extent_root = root->fs_info->extent_root;
        struct map_lookup *map;
        u64 dev_extent_len = 0;
        u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
        int i, ret = 0;
-       struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+       struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 
-       /* Just in case */
-       root = root->fs_info->chunk_root;
-       em_tree = &root->fs_info->mapping_tree.map_tree;
+       em_tree = &fs_info->mapping_tree.map_tree;
 
        read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, chunk_offset, 1);
@@ -2832,9 +2824,9 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
                return -EINVAL;
        }
        map = em->map_lookup;
-       lock_chunks(root->fs_info->chunk_root);
-       check_system_chunk(trans, extent_root, map->type);
-       unlock_chunks(root->fs_info->chunk_root);
+       mutex_lock(&fs_info->chunk_mutex);
+       check_system_chunk(trans, fs_info, map->type);
+       mutex_unlock(&fs_info->chunk_mutex);
 
        /*
         * Take the device list mutex to prevent races with the final phase of
@@ -2854,14 +2846,14 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
                }
 
                if (device->bytes_used > 0) {
-                       lock_chunks(root);
+                       mutex_lock(&fs_info->chunk_mutex);
                        btrfs_device_set_bytes_used(device,
                                        device->bytes_used - dev_extent_len);
-                       spin_lock(&root->fs_info->free_chunk_lock);
-                       root->fs_info->free_chunk_space += dev_extent_len;
-                       spin_unlock(&root->fs_info->free_chunk_lock);
-                       btrfs_clear_space_info_full(root->fs_info);
-                       unlock_chunks(root);
+                       spin_lock(&fs_info->free_chunk_lock);
+                       fs_info->free_chunk_space += dev_extent_len;
+                       spin_unlock(&fs_info->free_chunk_lock);
+                       btrfs_clear_space_info_full(fs_info);
+                       mutex_unlock(&fs_info->chunk_mutex);
                }
 
                if (map->stripes[i].dev) {
@@ -2875,23 +2867,24 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
        }
        mutex_unlock(&fs_devices->device_list_mutex);
 
-       ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
+       ret = btrfs_free_chunk(trans, fs_info, chunk_objectid, chunk_offset);
        if (ret) {
                btrfs_abort_transaction(trans, ret);
                goto out;
        }
 
-       trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
+       trace_btrfs_chunk_free(fs_info, map, chunk_offset, em->len);
 
        if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
-               ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
+               ret = btrfs_del_sys_chunk(fs_info, chunk_objectid,
+                                         chunk_offset);
                if (ret) {
                        btrfs_abort_transaction(trans, ret);
                        goto out;
                }
        }
 
-       ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
+       ret = btrfs_remove_block_group(trans, fs_info, chunk_offset, em);
        if (ret) {
                btrfs_abort_transaction(trans, ret);
                goto out;
@@ -2903,15 +2896,12 @@ out:
        return ret;
 }
 
-static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
+static int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 {
-       struct btrfs_root *extent_root;
+       struct btrfs_root *root = fs_info->chunk_root;
        struct btrfs_trans_handle *trans;
        int ret;
 
-       root = root->fs_info->chunk_root;
-       extent_root = root->fs_info->extent_root;
-
        /*
         * Prevent races with automatic removal of unused block groups.
         * After we relocate and before we remove the chunk with offset
@@ -2924,16 +2914,16 @@ static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
         * we release the path used to search the chunk/dev tree and before
         * the current task acquires this mutex and calls us.
         */
-       ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
+       ASSERT(mutex_is_locked(&fs_info->delete_unused_bgs_mutex));
 
-       ret = btrfs_can_relocate(extent_root, chunk_offset);
+       ret = btrfs_can_relocate(fs_info, chunk_offset);
        if (ret)
                return -ENOSPC;
 
        /* step one, relocate all the extents inside this chunk */
-       btrfs_scrub_pause(root);
-       ret = btrfs_relocate_block_group(extent_root, chunk_offset);
-       btrfs_scrub_continue(root);
+       btrfs_scrub_pause(fs_info);
+       ret = btrfs_relocate_block_group(fs_info, chunk_offset);
+       btrfs_scrub_continue(fs_info);
        if (ret)
                return ret;
 
@@ -2949,14 +2939,14 @@ static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
         * step two, delete the device extents and the
         * chunk tree entries
         */
-       ret = btrfs_remove_chunk(trans, root, chunk_offset);
-       btrfs_end_transaction(trans, extent_root);
+       ret = btrfs_remove_chunk(trans, fs_info, chunk_offset);
+       btrfs_end_transaction(trans);
        return ret;
 }
 
-static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
+static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info)
 {
-       struct btrfs_root *chunk_root = root->fs_info->chunk_root;
+       struct btrfs_root *chunk_root = fs_info->chunk_root;
        struct btrfs_path *path;
        struct extent_buffer *leaf;
        struct btrfs_chunk *chunk;
@@ -2977,10 +2967,10 @@ again:
        key.type = BTRFS_CHUNK_ITEM_KEY;
 
        while (1) {
-               mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
+               mutex_lock(&fs_info->delete_unused_bgs_mutex);
                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
                if (ret < 0) {
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        goto error;
                }
                BUG_ON(ret == 0); /* Corruption */
@@ -2988,7 +2978,7 @@ again:
                ret = btrfs_previous_item(chunk_root, path, key.objectid,
                                          key.type);
                if (ret)
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                if (ret < 0)
                        goto error;
                if (ret > 0)
@@ -3003,14 +2993,13 @@ again:
                btrfs_release_path(path);
 
                if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
-                       ret = btrfs_relocate_chunk(chunk_root,
-                                                  found_key.offset);
+                       ret = btrfs_relocate_chunk(fs_info, found_key.offset);
                        if (ret == -ENOSPC)
                                failed++;
                        else
                                BUG_ON(ret);
                }
-               mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+               mutex_unlock(&fs_info->delete_unused_bgs_mutex);
 
                if (found_key.offset == 0)
                        break;
@@ -3029,9 +3018,10 @@ error:
        return ret;
 }
 
-static int insert_balance_item(struct btrfs_root *root,
+static int insert_balance_item(struct btrfs_fs_info *fs_info,
                               struct btrfs_balance_control *bctl)
 {
+       struct btrfs_root *root = fs_info->tree_root;
        struct btrfs_trans_handle *trans;
        struct btrfs_balance_item *item;
        struct btrfs_disk_balance_args disk_bargs;
@@ -3062,7 +3052,7 @@ static int insert_balance_item(struct btrfs_root *root,
        leaf = path->nodes[0];
        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
 
-       memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
+       memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
 
        btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
        btrfs_set_balance_data(leaf, item, &disk_bargs);
@@ -3076,14 +3066,15 @@ static int insert_balance_item(struct btrfs_root *root,
        btrfs_mark_buffer_dirty(leaf);
 out:
        btrfs_free_path(path);
-       err = btrfs_commit_transaction(trans, root);
+       err = btrfs_commit_transaction(trans);
        if (err && !ret)
                ret = err;
        return ret;
 }
 
-static int del_balance_item(struct btrfs_root *root)
+static int del_balance_item(struct btrfs_fs_info *fs_info)
 {
+       struct btrfs_root *root = fs_info->tree_root;
        struct btrfs_trans_handle *trans;
        struct btrfs_path *path;
        struct btrfs_key key;
@@ -3114,7 +3105,7 @@ static int del_balance_item(struct btrfs_root *root)
        ret = btrfs_del_item(trans, root, path);
 out:
        btrfs_free_path(path);
-       err = btrfs_commit_transaction(trans, root);
+       err = btrfs_commit_transaction(trans);
        if (err && !ret)
                ret = err;
        return ret;
@@ -3369,11 +3360,11 @@ static int chunk_soft_convert_filter(u64 chunk_type,
        return 0;
 }
 
-static int should_balance_chunk(struct btrfs_root *root,
+static int should_balance_chunk(struct btrfs_fs_info *fs_info,
                                struct extent_buffer *leaf,
                                struct btrfs_chunk *chunk, u64 chunk_offset)
 {
-       struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+       struct btrfs_balance_control *bctl = fs_info->balance_ctl;
        struct btrfs_balance_args *bargs = NULL;
        u64 chunk_type = btrfs_chunk_type(leaf, chunk);
 
@@ -3398,10 +3389,10 @@ static int should_balance_chunk(struct btrfs_root *root,
 
        /* usage filter */
        if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
-           chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
+           chunk_usage_filter(fs_info, chunk_offset, bargs)) {
                return 0;
        } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
-           chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
+           chunk_usage_range_filter(fs_info, chunk_offset, bargs)) {
                return 0;
        }
 
@@ -3521,7 +3512,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
 
                ret = btrfs_grow_device(trans, device, old_size);
                if (ret) {
-                       btrfs_end_transaction(trans, dev_root);
+                       btrfs_end_transaction(trans);
                        /* btrfs_grow_device never returns ret > 0 */
                        WARN_ON(ret > 0);
                        btrfs_info_in_rcu(fs_info,
@@ -3531,7 +3522,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
                        goto error;
                }
 
-               btrfs_end_transaction(trans, dev_root);
+               btrfs_end_transaction(trans);
        }
 
        /* step two, relocate all the chunks */
@@ -3606,7 +3597,7 @@ again:
                        spin_unlock(&fs_info->balance_lock);
                }
 
-               ret = should_balance_chunk(chunk_root, leaf, chunk,
+               ret = should_balance_chunk(fs_info, leaf, chunk,
                                           found_key.offset);
 
                btrfs_release_path(path);
@@ -3659,9 +3650,9 @@ again:
                                goto error;
                        }
 
-                       ret = btrfs_force_chunk_alloc(trans, chunk_root,
+                       ret = btrfs_force_chunk_alloc(trans, fs_info,
                                                      BTRFS_BLOCK_GROUP_DATA);
-                       btrfs_end_transaction(trans, chunk_root);
+                       btrfs_end_transaction(trans);
                        if (ret < 0) {
                                mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                                goto error;
@@ -3669,8 +3660,7 @@ again:
                        chunk_reserved = 1;
                }
 
-               ret = btrfs_relocate_chunk(chunk_root,
-                                          found_key.offset);
+               ret = btrfs_relocate_chunk(fs_info, found_key.offset);
                mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                if (ret && ret != -ENOSPC)
                        goto error;
@@ -3741,7 +3731,7 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
        int ret;
 
        unset_balance_control(fs_info);
-       ret = del_balance_item(fs_info->tree_root);
+       ret = del_balance_item(fs_info);
        if (ret)
                btrfs_handle_fs_error(fs_info, ret, NULL);
 
@@ -3874,7 +3864,7 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
                                bctl->sys.target));
        }
 
-       ret = insert_balance_item(fs_info->tree_root, bctl);
+       ret = insert_balance_item(fs_info, bctl);
        if (ret && ret != -EEXIST)
                goto out;
 
@@ -4166,7 +4156,7 @@ static int btrfs_uuid_scan_kthread(void *data)
                }
 update_tree:
                if (!btrfs_is_empty_uuid(root_item.uuid)) {
-                       ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
+                       ret = btrfs_uuid_tree_add(trans, fs_info,
                                                  root_item.uuid,
                                                  BTRFS_UUID_KEY_SUBVOL,
                                                  key.objectid);
@@ -4178,7 +4168,7 @@ update_tree:
                }
 
                if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
-                       ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
+                       ret = btrfs_uuid_tree_add(trans, fs_info,
                                                  root_item.received_uuid,
                                                 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
                                                  key.objectid);
@@ -4191,7 +4181,7 @@ update_tree:
 
 skip:
                if (trans) {
-                       ret = btrfs_end_transaction(trans, fs_info->uuid_root);
+                       ret = btrfs_end_transaction(trans);
                        trans = NULL;
                        if (ret)
                                break;
@@ -4216,7 +4206,7 @@ skip:
 out:
        btrfs_free_path(path);
        if (trans && !IS_ERR(trans))
-               btrfs_end_transaction(trans, fs_info->uuid_root);
+               btrfs_end_transaction(trans);
        if (ret)
                btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
        else
@@ -4310,13 +4300,13 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
        if (IS_ERR(uuid_root)) {
                ret = PTR_ERR(uuid_root);
                btrfs_abort_transaction(trans, ret);
-               btrfs_end_transaction(trans, tree_root);
+               btrfs_end_transaction(trans);
                return ret;
        }
 
        fs_info->uuid_root = uuid_root;
 
-       ret = btrfs_commit_transaction(trans, tree_root);
+       ret = btrfs_commit_transaction(trans);
        if (ret)
                return ret;
 
@@ -4355,8 +4345,9 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
  */
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 {
+       struct btrfs_fs_info *fs_info = device->fs_info;
+       struct btrfs_root *root = fs_info->dev_root;
        struct btrfs_trans_handle *trans;
-       struct btrfs_root *root = device->dev_root;
        struct btrfs_dev_extent *dev_extent = NULL;
        struct btrfs_path *path;
        u64 length;
@@ -4368,7 +4359,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
        bool checked_pending_chunks = false;
        struct extent_buffer *l;
        struct btrfs_key key;
-       struct btrfs_super_block *super_copy = root->fs_info->super_copy;
+       struct btrfs_super_block *super_copy = fs_info->super_copy;
        u64 old_total = btrfs_super_total_bytes(super_copy);
        u64 old_size = btrfs_device_get_total_bytes(device);
        u64 diff = old_size - new_size;
@@ -4382,16 +4373,16 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 
        path->reada = READA_FORWARD;
 
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
 
        btrfs_device_set_total_bytes(device, new_size);
        if (device->writeable) {
                device->fs_devices->total_rw_bytes -= diff;
-               spin_lock(&root->fs_info->free_chunk_lock);
-               root->fs_info->free_chunk_space -= diff;
-               spin_unlock(&root->fs_info->free_chunk_lock);
+               spin_lock(&fs_info->free_chunk_lock);
+               fs_info->free_chunk_space -= diff;
+               spin_unlock(&fs_info->free_chunk_lock);
        }
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
 
 again:
        key.objectid = device->devid;
@@ -4399,16 +4390,16 @@ again:
        key.type = BTRFS_DEV_EXTENT_KEY;
 
        do {
-               mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
+               mutex_lock(&fs_info->delete_unused_bgs_mutex);
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                if (ret < 0) {
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        goto done;
                }
 
                ret = btrfs_previous_item(root, path, 0, key.type);
                if (ret)
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                if (ret < 0)
                        goto done;
                if (ret) {
@@ -4422,7 +4413,7 @@ again:
                btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 
                if (key.objectid != device->devid) {
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        btrfs_release_path(path);
                        break;
                }
@@ -4431,7 +4422,7 @@ again:
                length = btrfs_dev_extent_length(l, dev_extent);
 
                if (key.offset + length <= new_size) {
-                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        btrfs_release_path(path);
                        break;
                }
@@ -4439,8 +4430,8 @@ again:
                chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
                btrfs_release_path(path);
 
-               ret = btrfs_relocate_chunk(root, chunk_offset);
-               mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
+               ret = btrfs_relocate_chunk(fs_info, chunk_offset);
+               mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                if (ret && ret != -ENOSPC)
                        goto done;
                if (ret == -ENOSPC)
@@ -4463,7 +4454,7 @@ again:
                goto done;
        }
 
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
 
        /*
         * We checked in the above loop all device extents that were already in
@@ -4483,11 +4474,11 @@ again:
 
                if (contains_pending_extent(trans->transaction, device,
                                            &start, len)) {
-                       unlock_chunks(root);
+                       mutex_unlock(&fs_info->chunk_mutex);
                        checked_pending_chunks = true;
                        failed = 0;
                        retried = false;
-                       ret = btrfs_commit_transaction(trans, root);
+                       ret = btrfs_commit_transaction(trans);
                        if (ret)
                                goto done;
                        goto again;
@@ -4497,44 +4488,44 @@ again:
        btrfs_device_set_disk_total_bytes(device, new_size);
        if (list_empty(&device->resized_list))
                list_add_tail(&device->resized_list,
-                             &root->fs_info->fs_devices->resized_devices);
+                             &fs_info->fs_devices->resized_devices);
 
        WARN_ON(diff > old_total);
        btrfs_set_super_total_bytes(super_copy, old_total - diff);
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
 
        /* Now btrfs_update_device() will change the on-disk size. */
        ret = btrfs_update_device(trans, device);
-       btrfs_end_transaction(trans, root);
+       btrfs_end_transaction(trans);
 done:
        btrfs_free_path(path);
        if (ret) {
-               lock_chunks(root);
+               mutex_lock(&fs_info->chunk_mutex);
                btrfs_device_set_total_bytes(device, old_size);
                if (device->writeable)
                        device->fs_devices->total_rw_bytes += diff;
-               spin_lock(&root->fs_info->free_chunk_lock);
-               root->fs_info->free_chunk_space += diff;
-               spin_unlock(&root->fs_info->free_chunk_lock);
-               unlock_chunks(root);
+               spin_lock(&fs_info->free_chunk_lock);
+               fs_info->free_chunk_space += diff;
+               spin_unlock(&fs_info->free_chunk_lock);
+               mutex_unlock(&fs_info->chunk_mutex);
        }
        return ret;
 }
 
-static int btrfs_add_system_chunk(struct btrfs_root *root,
+static int btrfs_add_system_chunk(struct btrfs_fs_info *fs_info,
                           struct btrfs_key *key,
                           struct btrfs_chunk *chunk, int item_size)
 {
-       struct btrfs_super_block *super_copy = root->fs_info->super_copy;
+       struct btrfs_super_block *super_copy = fs_info->super_copy;
        struct btrfs_disk_key disk_key;
        u32 array_size;
        u8 *ptr;
 
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
        array_size = btrfs_super_sys_array_size(super_copy);
        if (array_size + item_size + sizeof(disk_key)
                        > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
-               unlock_chunks(root);
+               mutex_unlock(&fs_info->chunk_mutex);
                return -EFBIG;
        }
 
@@ -4545,7 +4536,7 @@ static int btrfs_add_system_chunk(struct btrfs_root *root,
        memcpy(ptr, chunk, item_size);
        item_size += sizeof(disk_key);
        btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
 
        return 0;
 }
@@ -4583,7 +4574,7 @@ static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
        btrfs_set_fs_incompat(info, RAID56);
 }
 
-#define BTRFS_MAX_DEVS(r) ((BTRFS_MAX_ITEM_SIZE(r            \
+#define BTRFS_MAX_DEVS(r) ((BTRFS_MAX_ITEM_SIZE(r->fs_info)            \
                        - sizeof(struct btrfs_chunk))           \
                        / sizeof(struct btrfs_stripe) + 1)
 
@@ -4593,10 +4584,10 @@ static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
                                / sizeof(struct btrfs_stripe) + 1)
 
 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
-                              struct btrfs_root *extent_root, u64 start,
+                              struct btrfs_fs_info *fs_info, u64 start,
                               u64 type)
 {
-       struct btrfs_fs_info *info = extent_root->fs_info;
+       struct btrfs_fs_info *info = trans->fs_info;
        struct btrfs_fs_devices *fs_devices = info->fs_devices;
        struct list_head *cur;
        struct map_lookup *map = NULL;
@@ -4762,12 +4753,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
        if (type & BTRFS_BLOCK_GROUP_RAID5) {
                raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
-                                               extent_root->stripesize);
+                                                        info->stripesize);
                data_stripes = num_stripes - 1;
        }
        if (type & BTRFS_BLOCK_GROUP_RAID6) {
                raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
-                                               extent_root->stripesize);
+                                                        info->stripesize);
                data_stripes = num_stripes - 2;
        }
 
@@ -4812,7 +4803,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                                                   j * stripe_size;
                }
        }
-       map->sector_size = extent_root->sectorsize;
+       map->sector_size = info->sectorsize;
        map->stripe_len = raid_stripe_len;
        map->io_align = raid_stripe_len;
        map->io_width = raid_stripe_len;
@@ -4821,7 +4812,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
        num_bytes = stripe_size * data_stripes;
 
-       trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
+       trace_btrfs_chunk_alloc(info, map, start, num_bytes);
 
        em = alloc_extent_map();
        if (!em) {
@@ -4837,7 +4828,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        em->block_len = em->len;
        em->orig_block_len = stripe_size;
 
-       em_tree = &extent_root->fs_info->mapping_tree.map_tree;
+       em_tree = &info->mapping_tree.map_tree;
        write_lock(&em_tree->lock);
        ret = add_extent_mapping(em_tree, em, 0);
        if (!ret) {
@@ -4850,7 +4841,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                goto error;
        }
 
-       ret = btrfs_make_block_group(trans, extent_root, 0, type,
+       ret = btrfs_make_block_group(trans, info, 0, type,
                                     BTRFS_FIRST_CHUNK_TREE_OBJECTID,
                                     start, num_bytes);
        if (ret)
@@ -4861,13 +4852,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
        }
 
-       spin_lock(&extent_root->fs_info->free_chunk_lock);
-       extent_root->fs_info->free_chunk_space -= (stripe_size *
-                                                  map->num_stripes);
-       spin_unlock(&extent_root->fs_info->free_chunk_lock);
+       spin_lock(&info->free_chunk_lock);
+       info->free_chunk_space -= (stripe_size * map->num_stripes);
+       spin_unlock(&info->free_chunk_lock);
 
        free_extent_map(em);
-       check_raid56_incompat_flag(extent_root->fs_info, type);
+       check_raid56_incompat_flag(info, type);
 
        kfree(devices_info);
        return 0;
@@ -4889,11 +4879,12 @@ error:
 }
 
 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *extent_root,
+                               struct btrfs_fs_info *fs_info,
                                u64 chunk_offset, u64 chunk_size)
 {
+       struct btrfs_root *extent_root = fs_info->extent_root;
+       struct btrfs_root *chunk_root = fs_info->chunk_root;
        struct btrfs_key key;
-       struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
        struct btrfs_device *device;
        struct btrfs_chunk *chunk;
        struct btrfs_stripe *stripe;
@@ -4906,20 +4897,19 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
        int i = 0;
        int ret = 0;
 
-       em_tree = &extent_root->fs_info->mapping_tree.map_tree;
+       em_tree = &fs_info->mapping_tree.map_tree;
        read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
        read_unlock(&em_tree->lock);
 
        if (!em) {
-               btrfs_crit(extent_root->fs_info,
-                          "unable to find logical %Lu len %Lu",
+               btrfs_crit(fs_info, "unable to find logical %Lu len %Lu",
                           chunk_offset, chunk_size);
                return -EINVAL;
        }
 
        if (em->start != chunk_offset || em->len != chunk_size) {
-               btrfs_crit(extent_root->fs_info,
+               btrfs_crit(fs_info,
                           "found a bad mapping, wanted %Lu-%Lu, found %Lu-%Lu",
                            chunk_offset, chunk_size, em->start, em->len);
                free_extent_map(em);
@@ -4943,7 +4933,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
         * at any time during that final phase of the device replace operation
         * (dev-replace.c:btrfs_dev_replace_finishing()).
         */
-       mutex_lock(&chunk_root->fs_info->fs_devices->device_list_mutex);
+       mutex_lock(&fs_info->fs_devices->device_list_mutex);
        for (i = 0; i < map->num_stripes; i++) {
                device = map->stripes[i].dev;
                dev_offset = map->stripes[i].physical;
@@ -4960,7 +4950,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                        break;
        }
        if (ret) {
-               mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
+               mutex_unlock(&fs_info->fs_devices->device_list_mutex);
                goto out;
        }
 
@@ -4974,7 +4964,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
                stripe++;
        }
-       mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
+       mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
        btrfs_set_stack_chunk_length(chunk, chunk_size);
        btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
@@ -4983,7 +4973,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
        btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
        btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
        btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
-       btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
+       btrfs_set_stack_chunk_sector_size(chunk, fs_info->sectorsize);
        btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
 
        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
@@ -4996,8 +4986,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                 * TODO: Cleanup of inserted chunk root in case of
                 * failure.
                 */
-               ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
-                                            item_size);
+               ret = btrfs_add_system_chunk(fs_info, &key, chunk, item_size);
        }
 
 out:
@@ -5014,36 +5003,34 @@ out:
  * bootstrap process of adding storage to a seed btrfs.
  */
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
-                     struct btrfs_root *extent_root, u64 type)
+                     struct btrfs_fs_info *fs_info, u64 type)
 {
        u64 chunk_offset;
 
-       ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
-       chunk_offset = find_next_chunk(extent_root->fs_info);
-       return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
+       ASSERT(mutex_is_locked(&fs_info->chunk_mutex));
+       chunk_offset = find_next_chunk(fs_info);
+       return __btrfs_alloc_chunk(trans, fs_info, chunk_offset, type);
 }
 
 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
-                                        struct btrfs_root *root,
+                                        struct btrfs_fs_info *fs_info,
                                         struct btrfs_device *device)
 {
+       struct btrfs_root *extent_root = fs_info->extent_root;
        u64 chunk_offset;
        u64 sys_chunk_offset;
        u64 alloc_profile;
-       struct btrfs_fs_info *fs_info = root->fs_info;
-       struct btrfs_root *extent_root = fs_info->extent_root;
        int ret;
 
        chunk_offset = find_next_chunk(fs_info);
        alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
-       ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
-                                 alloc_profile);
+       ret = __btrfs_alloc_chunk(trans, fs_info, chunk_offset, alloc_profile);
        if (ret)
                return ret;
 
-       sys_chunk_offset = find_next_chunk(root->fs_info);
+       sys_chunk_offset = find_next_chunk(fs_info);
        alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
-       ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
+       ret = __btrfs_alloc_chunk(trans, fs_info, sys_chunk_offset,
                                  alloc_profile);
        return ret;
 }
@@ -5066,11 +5053,11 @@ static inline int btrfs_chunk_max_errors(struct map_lookup *map)
        return max_errors;
 }
 
-int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
+int btrfs_chunk_readonly(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 {
        struct extent_map *em;
        struct map_lookup *map;
-       struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
+       struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
        int readonly = 0;
        int miss_ndevs = 0;
        int i;
@@ -5182,14 +5169,14 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
        return ret;
 }
 
-unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
+unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
                                    struct btrfs_mapping_tree *map_tree,
                                    u64 logical)
 {
        struct extent_map *em;
        struct map_lookup *map;
        struct extent_map_tree *em_tree = &map_tree->map_tree;
-       unsigned long len = root->sectorsize;
+       unsigned long len = fs_info->sectorsize;
 
        read_lock(&em_tree->lock);
        em = lookup_extent_mapping(em_tree, logical, len);
@@ -5329,7 +5316,8 @@ void btrfs_put_bbio(struct btrfs_bio *bbio)
                kfree(bbio);
 }
 
-static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
+static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
+                            enum btrfs_map_op op,
                             u64 logical, u64 *length,
                             struct btrfs_bio **bbio_ret,
                             int mirror_num, int need_raid_map)
@@ -5414,7 +5402,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                raid56_full_stripe_start *= full_stripe_len;
        }
 
-       if (op == REQ_OP_DISCARD) {
+       if (op == BTRFS_MAP_DISCARD) {
                /* we don't discard raid56 yet */
                if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
                        ret = -EOPNOTSUPP;
@@ -5427,7 +5415,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                   For other RAID types and for RAID[56] reads, just allow a single
                   stripe (on a single disk). */
                if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
-                   (op == REQ_OP_WRITE)) {
+                   (op == BTRFS_MAP_WRITE)) {
                        max_len = stripe_len * nr_data_stripes(map) -
                                (offset - raid56_full_stripe_start);
                } else {
@@ -5452,8 +5440,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                btrfs_dev_replace_set_lock_blocking(dev_replace);
 
        if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
-           op != REQ_OP_WRITE && op != REQ_OP_DISCARD &&
-           op != REQ_GET_READ_MIRRORS && dev_replace->tgtdev != NULL) {
+           op != BTRFS_MAP_WRITE && op != BTRFS_MAP_DISCARD &&
+           op != BTRFS_MAP_GET_READ_MIRRORS && dev_replace->tgtdev != NULL) {
                /*
                 * in dev-replace case, for repair case (that's the only
                 * case where the mirror is selected explicitly when
@@ -5474,7 +5462,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                int found = 0;
                u64 physical_of_found = 0;
 
-               ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
+               ret = __btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
                             logical, &tmp_length, &tmp_bbio, 0, 0);
                if (ret) {
                        WARN_ON(tmp_bbio != NULL);
@@ -5484,7 +5472,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                tmp_num_stripes = tmp_bbio->num_stripes;
                if (mirror_num > tmp_num_stripes) {
                        /*
-                        * REQ_GET_READ_MIRRORS does not contain this
+                        * BTRFS_MAP_GET_READ_MIRRORS does not contain this
                         * mirror, that means that the requested area
                         * is not left of the left cursor
                         */
@@ -5540,17 +5528,17 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                            (offset + *length);
 
        if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
-               if (op == REQ_OP_DISCARD)
+               if (op == BTRFS_MAP_DISCARD)
                        num_stripes = min_t(u64, map->num_stripes,
                                            stripe_nr_end - stripe_nr_orig);
                stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
                                &stripe_index);
-               if (op != REQ_OP_WRITE && op != REQ_OP_DISCARD &&
-                   op != REQ_GET_READ_MIRRORS)
+               if (op != BTRFS_MAP_WRITE && op != BTRFS_MAP_DISCARD &&
+                   op != BTRFS_MAP_GET_READ_MIRRORS)
                        mirror_num = 1;
        } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
-               if (op == REQ_OP_WRITE || op == REQ_OP_DISCARD ||
-                   op == REQ_GET_READ_MIRRORS)
+               if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_DISCARD ||
+                   op == BTRFS_MAP_GET_READ_MIRRORS)
                        num_stripes = map->num_stripes;
                else if (mirror_num)
                        stripe_index = mirror_num - 1;
@@ -5563,8 +5551,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                }
 
        } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
-               if (op == REQ_OP_WRITE || op == REQ_OP_DISCARD ||
-                   op == REQ_GET_READ_MIRRORS) {
+               if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_DISCARD ||
+                   op == BTRFS_MAP_GET_READ_MIRRORS) {
                        num_stripes = map->num_stripes;
                } else if (mirror_num) {
                        stripe_index = mirror_num - 1;
@@ -5578,9 +5566,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
                stripe_index *= map->sub_stripes;
 
-               if (op == REQ_OP_WRITE || op == REQ_GET_READ_MIRRORS)
+               if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS)
                        num_stripes = map->sub_stripes;
-               else if (op == REQ_OP_DISCARD)
+               else if (op == BTRFS_MAP_DISCARD)
                        num_stripes = min_t(u64, map->sub_stripes *
                                            (stripe_nr_end - stripe_nr_orig),
                                            map->num_stripes);
@@ -5598,7 +5586,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
 
        } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
                if (need_raid_map &&
-                   (op == REQ_OP_WRITE || op == REQ_GET_READ_MIRRORS ||
+                   (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS ||
                     mirror_num > 1)) {
                        /* push stripe_nr back to the start of the full stripe */
                        stripe_nr = div_u64(raid56_full_stripe_start,
@@ -5626,8 +5614,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                        /* We distribute the parity blocks across stripes */
                        div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
                                        &stripe_index);
-                       if ((op != REQ_OP_WRITE && op != REQ_OP_DISCARD &&
-                           op != REQ_GET_READ_MIRRORS) && mirror_num <= 1)
+                       if ((op != BTRFS_MAP_WRITE && op != BTRFS_MAP_DISCARD &&
+                           op != BTRFS_MAP_GET_READ_MIRRORS) && mirror_num <= 1)
                                mirror_num = 1;
                }
        } else {
@@ -5650,9 +5638,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
 
        num_alloc_stripes = num_stripes;
        if (dev_replace_is_ongoing) {
-               if (op == REQ_OP_WRITE || op == REQ_OP_DISCARD)
+               if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_DISCARD)
                        num_alloc_stripes <<= 1;
-               if (op == REQ_GET_READ_MIRRORS)
+               if (op == BTRFS_MAP_GET_READ_MIRRORS)
                        num_alloc_stripes++;
                tgtdev_indexes = num_stripes;
        }
@@ -5668,7 +5656,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
        /* build raid_map */
        if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
            need_raid_map &&
-           ((op == REQ_OP_WRITE || op == REQ_GET_READ_MIRRORS) ||
+           ((op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS) ||
            mirror_num > 1)) {
                u64 tmp;
                unsigned rot;
@@ -5693,7 +5681,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                                RAID6_Q_STRIPE;
        }
 
-       if (op == REQ_OP_DISCARD) {
+       if (op == BTRFS_MAP_DISCARD) {
                u32 factor = 0;
                u32 sub_stripes = 0;
                u64 stripes_per_dev = 0;
@@ -5773,7 +5761,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                }
        }
 
-       if (op == REQ_OP_WRITE || op == REQ_GET_READ_MIRRORS)
+       if (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS)
                max_errors = btrfs_chunk_max_errors(map);
 
        if (bbio->raid_map)
@@ -5781,7 +5769,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
 
        tgtdev_indexes = 0;
        if (dev_replace_is_ongoing &&
-          (op == REQ_OP_WRITE || op == REQ_OP_DISCARD) &&
+          (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_DISCARD) &&
            dev_replace->tgtdev != NULL) {
                int index_where_to_add;
                u64 srcdev_devid = dev_replace->srcdev->devid;
@@ -5816,7 +5804,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
                        }
                }
                num_stripes = index_where_to_add;
-       } else if (dev_replace_is_ongoing && (op == REQ_GET_READ_MIRRORS) &&
+       } else if (dev_replace_is_ongoing &&
+                  op == BTRFS_MAP_GET_READ_MIRRORS &&
                   dev_replace->tgtdev != NULL) {
                u64 srcdev_devid = dev_replace->srcdev->devid;
                int index_srcdev = 0;
@@ -5888,7 +5877,7 @@ out:
        return ret;
 }
 
-int btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
+int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                      u64 logical, u64 *length,
                      struct btrfs_bio **bbio_ret, int mirror_num)
 {
@@ -5897,7 +5886,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, int op,
 }
 
 /* For Scrub/replace */
-int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int op,
+int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                     u64 logical, u64 *length,
                     struct btrfs_bio **bbio_ret, int mirror_num,
                     int need_raid_map)
@@ -6069,10 +6058,10 @@ static void btrfs_end_bio(struct bio *bio)
  * This will add one bio to the pending list for a device and make sure
  * the work struct is scheduled.
  */
-static noinline void btrfs_schedule_bio(struct btrfs_root *root,
-                                       struct btrfs_device *device,
+static noinline void btrfs_schedule_bio(struct btrfs_device *device,
                                        struct bio *bio)
 {
+       struct btrfs_fs_info *fs_info = device->fs_info;
        int should_queue = 1;
        struct btrfs_pending_bios *pending_bios;
 
@@ -6095,7 +6084,7 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root,
         * made progress against dirty pages when we've really just put it
         * on a queue for later
         */
-       atomic_inc(&root->fs_info->nr_async_bios);
+       atomic_inc(&fs_info->nr_async_bios);
        WARN_ON(bio->bi_next);
        bio->bi_next = NULL;
 
@@ -6117,15 +6106,14 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root,
        spin_unlock(&device->io_lock);
 
        if (should_queue)
-               btrfs_queue_work(root->fs_info->submit_workers,
-                                &device->work);
+               btrfs_queue_work(fs_info->submit_workers, &device->work);
 }
 
-static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
-                             struct bio *bio, u64 physical, int dev_nr,
-                             int async)
+static void submit_stripe_bio(struct btrfs_bio *bbio, struct bio *bio,
+                             u64 physical, int dev_nr, int async)
 {
        struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
+       struct btrfs_fs_info *fs_info = bbio->fs_info;
 
        bio->bi_private = bbio;
        btrfs_io_bio(bio)->stripe_index = dev_nr;
@@ -6148,10 +6136,10 @@ static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
 #endif
        bio->bi_bdev = dev->bdev;
 
-       btrfs_bio_counter_inc_noblocked(root->fs_info);
+       btrfs_bio_counter_inc_noblocked(fs_info);
 
        if (async)
-               btrfs_schedule_bio(root, dev, bio);
+               btrfs_schedule_bio(dev, bio);
        else
                btrfsic_submit_bio(bio);
 }
@@ -6170,7 +6158,7 @@ static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
        }
 }
 
-int btrfs_map_bio(struct btrfs_root *root, struct bio *bio,
+int btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
                  int mirror_num, int async_submit)
 {
        struct btrfs_device *dev;
@@ -6186,11 +6174,11 @@ int btrfs_map_bio(struct btrfs_root *root, struct bio *bio,
        length = bio->bi_iter.bi_size;
        map_length = length;
 
-       btrfs_bio_counter_inc_blocked(root->fs_info);
-       ret = __btrfs_map_block(root->fs_info, bio_op(bio), logical,
+       btrfs_bio_counter_inc_blocked(fs_info);
+       ret = __btrfs_map_block(fs_info, bio_op(bio), logical,
                                &map_length, &bbio, mirror_num, 1);
        if (ret) {
-               btrfs_bio_counter_dec(root->fs_info);
+               btrfs_bio_counter_dec(fs_info);
                return ret;
        }
 
@@ -6198,7 +6186,7 @@ int btrfs_map_bio(struct btrfs_root *root, struct bio *bio,
        bbio->orig_bio = first_bio;
        bbio->private = first_bio->bi_private;
        bbio->end_io = first_bio->bi_end_io;
-       bbio->fs_info = root->fs_info;
+       bbio->fs_info = fs_info;
        atomic_set(&bbio->stripes_pending, bbio->num_stripes);
 
        if ((bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
@@ -6206,18 +6194,19 @@ int btrfs_map_bio(struct btrfs_root *root, struct bio *bio,
                /* In this case, map_length has been set to the length of
                   a single stripe; not the whole write */
                if (bio_op(bio) == REQ_OP_WRITE) {
-                       ret = raid56_parity_write(root, bio, bbio, map_length);
+                       ret = raid56_parity_write(fs_info, bio, bbio,
+                                                 map_length);
                } else {
-                       ret = raid56_parity_recover(root, bio, bbio, map_length,
-                                                   mirror_num, 1);
+                       ret = raid56_parity_recover(fs_info, bio, bbio,
+                                                   map_length, mirror_num, 1);
                }
 
-               btrfs_bio_counter_dec(root->fs_info);
+               btrfs_bio_counter_dec(fs_info);
                return ret;
        }
 
        if (map_length < length) {
-               btrfs_crit(root->fs_info,
+               btrfs_crit(fs_info,
                           "mapping failed logical %llu bio len %llu len %llu",
                           logical, length, map_length);
                BUG();
@@ -6237,11 +6226,10 @@ int btrfs_map_bio(struct btrfs_root *root, struct bio *bio,
                } else
                        bio = first_bio;
 
-               submit_stripe_bio(root, bbio, bio,
-                                 bbio->stripes[dev_nr].physical, dev_nr,
-                                 async_submit);
+               submit_stripe_bio(bbio, bio, bbio->stripes[dev_nr].physical,
+                                 dev_nr, async_submit);
        }
-       btrfs_bio_counter_dec(root->fs_info);
+       btrfs_bio_counter_dec(fs_info);
        return 0;
 }
 
@@ -6265,8 +6253,7 @@ struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
        return NULL;
 }
 
-static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
-                                           struct btrfs_fs_devices *fs_devices,
+static struct btrfs_device *add_missing_dev(struct btrfs_fs_devices *fs_devices,
                                            u64 devid, u8 *dev_uuid)
 {
        struct btrfs_device *device;
@@ -6337,7 +6324,7 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
 }
 
 /* Return -EIO if any error, otherwise return 0. */
-static int btrfs_check_chunk_valid(struct btrfs_root *root,
+static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
                                   struct extent_buffer *leaf,
                                   struct btrfs_chunk *chunk, u64 logical)
 {
@@ -6354,33 +6341,31 @@ static int btrfs_check_chunk_valid(struct btrfs_root *root,
        type = btrfs_chunk_type(leaf, chunk);
 
        if (!num_stripes) {
-               btrfs_err(root->fs_info, "invalid chunk num_stripes: %u",
+               btrfs_err(fs_info, "invalid chunk num_stripes: %u",
                          num_stripes);
                return -EIO;
        }
-       if (!IS_ALIGNED(logical, root->sectorsize)) {
-               btrfs_err(root->fs_info,
-                         "invalid chunk logical %llu", logical);
+       if (!IS_ALIGNED(logical, fs_info->sectorsize)) {
+               btrfs_err(fs_info, "invalid chunk logical %llu", logical);
                return -EIO;
        }
-       if (btrfs_chunk_sector_size(leaf, chunk) != root->sectorsize) {
-               btrfs_err(root->fs_info, "invalid chunk sectorsize %u",
+       if (btrfs_chunk_sector_size(leaf, chunk) != fs_info->sectorsize) {
+               btrfs_err(fs_info, "invalid chunk sectorsize %u",
                          btrfs_chunk_sector_size(leaf, chunk));
                return -EIO;
        }
-       if (!length || !IS_ALIGNED(length, root->sectorsize)) {
-               btrfs_err(root->fs_info,
-                       "invalid chunk length %llu", length);
+       if (!length || !IS_ALIGNED(length, fs_info->sectorsize)) {
+               btrfs_err(fs_info, "invalid chunk length %llu", length);
                return -EIO;
        }
        if (!is_power_of_2(stripe_len) || stripe_len != BTRFS_STRIPE_LEN) {
-               btrfs_err(root->fs_info, "invalid chunk stripe length: %llu",
+               btrfs_err(fs_info, "invalid chunk stripe length: %llu",
                          stripe_len);
                return -EIO;
        }
        if (~(BTRFS_BLOCK_GROUP_TYPE_MASK | BTRFS_BLOCK_GROUP_PROFILE_MASK) &
            type) {
-               btrfs_err(root->fs_info, "unrecognized chunk type: %llu",
+               btrfs_err(fs_info, "unrecognized chunk type: %llu",
                          ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
                            BTRFS_BLOCK_GROUP_PROFILE_MASK) &
                          btrfs_chunk_type(leaf, chunk));
@@ -6393,7 +6378,7 @@ static int btrfs_check_chunk_valid(struct btrfs_root *root,
            (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
            ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
             num_stripes != 1)) {
-               btrfs_err(root->fs_info,
+               btrfs_err(fs_info,
                        "invalid num_stripes:sub_stripes %u:%u for profile %llu",
                        num_stripes, sub_stripes,
                        type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
@@ -6403,11 +6388,11 @@ static int btrfs_check_chunk_valid(struct btrfs_root *root,
        return 0;
 }
 
-static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
+static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
                          struct extent_buffer *leaf,
                          struct btrfs_chunk *chunk)
 {
-       struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
+       struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
        struct map_lookup *map;
        struct extent_map *em;
        u64 logical;
@@ -6424,7 +6409,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
        stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
        num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
 
-       ret = btrfs_check_chunk_valid(root, leaf, chunk, logical);
+       ret = btrfs_check_chunk_valid(fs_info, leaf, chunk, logical);
        if (ret)
                return ret;
 
@@ -6471,23 +6456,22 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                read_extent_buffer(leaf, uuid, (unsigned long)
                                   btrfs_stripe_dev_uuid_nr(chunk, i),
                                   BTRFS_UUID_SIZE);
-               map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
+               map->stripes[i].dev = btrfs_find_device(fs_info, devid,
                                                        uuid, NULL);
                if (!map->stripes[i].dev &&
-                   !btrfs_test_opt(root->fs_info, DEGRADED)) {
+                   !btrfs_test_opt(fs_info, DEGRADED)) {
                        free_extent_map(em);
                        return -EIO;
                }
                if (!map->stripes[i].dev) {
                        map->stripes[i].dev =
-                               add_missing_dev(root, root->fs_info->fs_devices,
-                                               devid, uuid);
+                               add_missing_dev(fs_info->fs_devices, devid,
+                                               uuid);
                        if (!map->stripes[i].dev) {
                                free_extent_map(em);
                                return -EIO;
                        }
-                       btrfs_warn(root->fs_info,
-                                  "devid %llu uuid %pU is missing",
+                       btrfs_warn(fs_info, "devid %llu uuid %pU is missing",
                                   devid, uuid);
                }
                map->stripes[i].dev->in_fs_metadata = 1;
@@ -6525,7 +6509,7 @@ static void fill_device_from_item(struct extent_buffer *leaf,
        read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
 }
 
-static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
+static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info,
                                                  u8 *fsid)
 {
        struct btrfs_fs_devices *fs_devices;
@@ -6533,7 +6517,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
 
        BUG_ON(!mutex_is_locked(&uuid_mutex));
 
-       fs_devices = root->fs_info->fs_devices->seed;
+       fs_devices = fs_info->fs_devices->seed;
        while (fs_devices) {
                if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
                        return fs_devices;
@@ -6543,7 +6527,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
 
        fs_devices = find_fsid(fsid);
        if (!fs_devices) {
-               if (!btrfs_test_opt(root->fs_info, DEGRADED))
+               if (!btrfs_test_opt(fs_info, DEGRADED))
                        return ERR_PTR(-ENOENT);
 
                fs_devices = alloc_fs_devices(fsid);
@@ -6560,7 +6544,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
                return fs_devices;
 
        ret = __btrfs_open_devices(fs_devices, FMODE_READ,
-                                  root->fs_info->bdev_holder);
+                                  fs_info->bdev_holder);
        if (ret) {
                free_fs_devices(fs_devices);
                fs_devices = ERR_PTR(ret);
@@ -6574,17 +6558,17 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
                goto out;
        }
 
-       fs_devices->seed = root->fs_info->fs_devices->seed;
-       root->fs_info->fs_devices->seed = fs_devices;
+       fs_devices->seed = fs_info->fs_devices->seed;
+       fs_info->fs_devices->seed = fs_devices;
 out:
        return fs_devices;
 }
 
-static int read_one_dev(struct btrfs_root *root,
+static int read_one_dev(struct btrfs_fs_info *fs_info,
                        struct extent_buffer *leaf,
                        struct btrfs_dev_item *dev_item)
 {
-       struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+       struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
        struct btrfs_device *device;
        u64 devid;
        int ret;
@@ -6597,24 +6581,24 @@ static int read_one_dev(struct btrfs_root *root,
        read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
                           BTRFS_UUID_SIZE);
 
-       if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
-               fs_devices = open_seed_devices(root, fs_uuid);
+       if (memcmp(fs_uuid, fs_info->fsid, BTRFS_UUID_SIZE)) {
+               fs_devices = open_seed_devices(fs_info, fs_uuid);
                if (IS_ERR(fs_devices))
                        return PTR_ERR(fs_devices);
        }
 
-       device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
+       device = btrfs_find_device(fs_info, devid, dev_uuid, fs_uuid);
        if (!device) {
-               if (!btrfs_test_opt(root->fs_info, DEGRADED))
+               if (!btrfs_test_opt(fs_info, DEGRADED))
                        return -EIO;
 
-               device = add_missing_dev(root, fs_devices, devid, dev_uuid);
+               device = add_missing_dev(fs_devices, devid, dev_uuid);
                if (!device)
                        return -ENOMEM;
-               btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
+               btrfs_warn(fs_info, "devid %llu uuid %pU missing",
                                devid, dev_uuid);
        } else {
-               if (!device->bdev && !btrfs_test_opt(root->fs_info, DEGRADED))
+               if (!device->bdev && !btrfs_test_opt(fs_info, DEGRADED))
                        return -EIO;
 
                if(!device->bdev && !device->missing) {
@@ -6643,7 +6627,7 @@ static int read_one_dev(struct btrfs_root *root,
                }
        }
 
-       if (device->fs_devices != root->fs_info->fs_devices) {
+       if (device->fs_devices != fs_info->fs_devices) {
                BUG_ON(device->writeable);
                if (device->generation !=
                    btrfs_device_generation(leaf, dev_item))
@@ -6654,18 +6638,18 @@ static int read_one_dev(struct btrfs_root *root,
        device->in_fs_metadata = 1;
        if (device->writeable && !device->is_tgtdev_for_dev_replace) {
                device->fs_devices->total_rw_bytes += device->total_bytes;
-               spin_lock(&root->fs_info->free_chunk_lock);
-               root->fs_info->free_chunk_space += device->total_bytes -
+               spin_lock(&fs_info->free_chunk_lock);
+               fs_info->free_chunk_space += device->total_bytes -
                        device->bytes_used;
-               spin_unlock(&root->fs_info->free_chunk_lock);
+               spin_unlock(&fs_info->free_chunk_lock);
        }
        ret = 0;
        return ret;
 }
 
-int btrfs_read_sys_array(struct btrfs_root *root)
+int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
 {
-       struct btrfs_fs_info *fs_info = root->fs_info;
+       struct btrfs_root *root = fs_info->tree_root;
        struct btrfs_super_block *super_copy = fs_info->super_copy;
        struct extent_buffer *sb;
        struct btrfs_disk_key *disk_key;
@@ -6680,13 +6664,13 @@ int btrfs_read_sys_array(struct btrfs_root *root)
        u64 type;
        struct btrfs_key key;
 
-       ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
+       ASSERT(BTRFS_SUPER_INFO_SIZE <= fs_info->nodesize);
        /*
         * This will create extent buffer of nodesize, superblock size is
         * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
         * overallocate but we can keep it as-is, only the first page is used.
         */
-       sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
+       sb = btrfs_find_create_tree_block(fs_info, BTRFS_SUPER_INFO_OFFSET);
        if (IS_ERR(sb))
                return PTR_ERR(sb);
        set_extent_buffer_uptodate(sb);
@@ -6757,7 +6741,7 @@ int btrfs_read_sys_array(struct btrfs_root *root)
                        if (cur_offset + len > array_size)
                                goto out_short_read;
 
-                       ret = read_one_chunk(root, &key, sb, chunk);
+                       ret = read_one_chunk(fs_info, &key, sb, chunk);
                        if (ret)
                                break;
                } else {
@@ -6783,8 +6767,9 @@ out_short_read:
        return -EIO;
 }
 
-int btrfs_read_chunk_tree(struct btrfs_root *root)
+int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info)
 {
+       struct btrfs_root *root = fs_info->chunk_root;
        struct btrfs_path *path;
        struct extent_buffer *leaf;
        struct btrfs_key key;
@@ -6793,14 +6778,12 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
        int slot;
        u64 total_dev = 0;
 
-       root = root->fs_info->chunk_root;
-
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
 
        mutex_lock(&uuid_mutex);
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
 
        /*
         * Read all device items, and then all the chunk items. All
@@ -6830,14 +6813,14 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
                        struct btrfs_dev_item *dev_item;
                        dev_item = btrfs_item_ptr(leaf, slot,
                                                  struct btrfs_dev_item);
-                       ret = read_one_dev(root, leaf, dev_item);
+                       ret = read_one_dev(fs_info, leaf, dev_item);
                        if (ret)
                                goto error;
                        total_dev++;
                } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
                        struct btrfs_chunk *chunk;
                        chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
-                       ret = read_one_chunk(root, &found_key, leaf, chunk);
+                       ret = read_one_chunk(fs_info, &found_key, leaf, chunk);
                        if (ret)
                                goto error;
                }
@@ -6848,26 +6831,26 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
         * After loading chunk tree, we've got all device information,
         * do another round of validation checks.
         */
-       if (total_dev != root->fs_info->fs_devices->total_devices) {
-               btrfs_err(root->fs_info,
+       if (total_dev != fs_info->fs_devices->total_devices) {
+               btrfs_err(fs_info,
           "super_num_devices %llu mismatch with num_devices %llu found here",
-                         btrfs_super_num_devices(root->fs_info->super_copy),
+                         btrfs_super_num_devices(fs_info->super_copy),
                          total_dev);
                ret = -EINVAL;
                goto error;
        }
-       if (btrfs_super_total_bytes(root->fs_info->super_copy) <
-           root->fs_info->fs_devices->total_rw_bytes) {
-               btrfs_err(root->fs_info,
+       if (btrfs_super_total_bytes(fs_info->super_copy) <
+           fs_info->fs_devices->total_rw_bytes) {
+               btrfs_err(fs_info,
        "super_total_bytes %llu mismatch with fs_devices total_rw_bytes %llu",
-                         btrfs_super_total_bytes(root->fs_info->super_copy),
-                         root->fs_info->fs_devices->total_rw_bytes);
+                         btrfs_super_total_bytes(fs_info->super_copy),
+                         fs_info->fs_devices->total_rw_bytes);
                ret = -EINVAL;
                goto error;
        }
        ret = 0;
 error:
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
        mutex_unlock(&uuid_mutex);
 
        btrfs_free_path(path);
@@ -6882,7 +6865,7 @@ void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
        while (fs_devices) {
                mutex_lock(&fs_devices->device_list_mutex);
                list_for_each_entry(device, &fs_devices->devices, dev_list)
-                       device->dev_root = fs_info->dev_root;
+                       device->fs_info = fs_info;
                mutex_unlock(&fs_devices->device_list_mutex);
 
                fs_devices = fs_devices->seed;
@@ -6959,9 +6942,10 @@ out:
 }
 
 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *dev_root,
+                               struct btrfs_fs_info *fs_info,
                                struct btrfs_device *device)
 {
+       struct btrfs_root *dev_root = fs_info->dev_root;
        struct btrfs_path *path;
        struct btrfs_key key;
        struct extent_buffer *eb;
@@ -6977,7 +6961,7 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
        BUG_ON(!path);
        ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
        if (ret < 0) {
-               btrfs_warn_in_rcu(dev_root->fs_info,
+               btrfs_warn_in_rcu(fs_info,
                        "error %d while searching for dev_stats item for device %s",
                              ret, rcu_str_deref(device->name));
                goto out;
@@ -6988,7 +6972,7 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
                /* need to delete old one and insert a new one */
                ret = btrfs_del_item(trans, dev_root, path);
                if (ret != 0) {
-                       btrfs_warn_in_rcu(dev_root->fs_info,
+                       btrfs_warn_in_rcu(fs_info,
                                "delete too small dev_stats item for device %s failed %d",
                                      rcu_str_deref(device->name), ret);
                        goto out;
@@ -7002,7 +6986,7 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans,
                ret = btrfs_insert_empty_item(trans, dev_root, path,
                                              &key, sizeof(*ptr));
                if (ret < 0) {
-                       btrfs_warn_in_rcu(dev_root->fs_info,
+                       btrfs_warn_in_rcu(fs_info,
                                "insert dev_stats item for device %s failed %d",
                                rcu_str_deref(device->name), ret);
                        goto out;
@@ -7027,7 +7011,6 @@ out:
 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
                        struct btrfs_fs_info *fs_info)
 {
-       struct btrfs_root *dev_root = fs_info->dev_root;
        struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
        struct btrfs_device *device;
        int stats_cnt;
@@ -7039,7 +7022,7 @@ int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
                        continue;
 
                stats_cnt = atomic_read(&device->dev_stats_ccnt);
-               ret = update_dev_stat_item(trans, dev_root, device);
+               ret = update_dev_stat_item(trans, fs_info, device);
                if (!ret)
                        atomic_sub(stats_cnt, &device->dev_stats_ccnt);
        }
@@ -7058,7 +7041,7 @@ static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
 {
        if (!dev->dev_stats_valid)
                return;
-       btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
+       btrfs_err_rl_in_rcu(dev->fs_info,
                "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
                           rcu_str_deref(dev->name),
                           btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
@@ -7078,7 +7061,7 @@ static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
        if (i == BTRFS_DEV_STAT_VALUES_MAX)
                return; /* all values == 0, suppress message */
 
-       btrfs_info_in_rcu(dev->dev_root->fs_info,
+       btrfs_info_in_rcu(dev->fs_info,
                "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
               rcu_str_deref(dev->name),
               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
@@ -7088,24 +7071,22 @@ static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
 }
 
-int btrfs_get_dev_stats(struct btrfs_root *root,
+int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
                        struct btrfs_ioctl_get_dev_stats *stats)
 {
        struct btrfs_device *dev;
-       struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+       struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
        int i;
 
        mutex_lock(&fs_devices->device_list_mutex);
-       dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
+       dev = btrfs_find_device(fs_info, stats->devid, NULL, NULL);
        mutex_unlock(&fs_devices->device_list_mutex);
 
        if (!dev) {
-               btrfs_warn(root->fs_info,
-                          "get dev_stats failed, device not found");
+               btrfs_warn(fs_info, "get dev_stats failed, device not found");
                return -ENODEV;
        } else if (!dev->dev_stats_valid) {
-               btrfs_warn(root->fs_info,
-                          "get dev_stats failed, not yet valid");
+               btrfs_warn(fs_info, "get dev_stats failed, not yet valid");
                return -ENODEV;
        } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
                for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
@@ -7168,18 +7149,18 @@ void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
                return;
 
        mutex_lock(&fs_devices->device_list_mutex);
-       lock_chunks(fs_info->dev_root);
+       mutex_lock(&fs_info->chunk_mutex);
        list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
                                 resized_list) {
                list_del_init(&curr->resized_list);
                curr->commit_total_bytes = curr->disk_total_bytes;
        }
-       unlock_chunks(fs_info->dev_root);
+       mutex_unlock(&fs_info->chunk_mutex);
        mutex_unlock(&fs_devices->device_list_mutex);
 }
 
 /* Must be invoked during the transaction commit */
-void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
+void btrfs_update_commit_device_bytes_used(struct btrfs_fs_info *fs_info,
                                        struct btrfs_transaction *transaction)
 {
        struct extent_map *em;
@@ -7191,7 +7172,7 @@ void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
                return;
 
        /* In order to kick the device replace finish process */
-       lock_chunks(root);
+       mutex_lock(&fs_info->chunk_mutex);
        list_for_each_entry(em, &transaction->pending_chunks, list) {
                map = em->map_lookup;
 
@@ -7200,7 +7181,7 @@ void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
                        dev->commit_bytes_used = dev->bytes_used;
                }
        }
-       unlock_chunks(root);
+       mutex_unlock(&fs_info->chunk_mutex);
 }
 
 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)