From c28418daed603d4943edc8b213b91f8d1e2b9fe3 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 19 Oct 2017 15:12:58 +0800 Subject: btrfs-progs: mkfs/rootdir: Shrink fs for rootdir option Use the new dev extent based shrink method for rootdir option. This restores the original behaviour when --rootdir will create a minimal filesystem size. Signed-off-by: Qu Wenruo [ update changelog ] Signed-off-by: David Sterba --- mkfs/rootdir.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) (limited to 'mkfs/rootdir.c') diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c index f936273c..0dc022b0 100644 --- a/mkfs/rootdir.c +++ b/mkfs/rootdir.c @@ -822,3 +822,114 @@ out: return ret; } + +/* + * Set device size to @new_size. + * + * Only used for --rootdir option. + * We will need to reset the following values: + * 1) dev item in chunk tree + * 2) super->dev_item + * 3) super->total_bytes + */ +static int set_device_size(struct btrfs_fs_info *fs_info, + struct btrfs_device *device, u64 new_size) +{ + struct btrfs_root *chunk_root = fs_info->chunk_root; + struct btrfs_trans_handle *trans; + struct btrfs_dev_item *di; + struct btrfs_path path; + struct btrfs_key key; + int ret; + + /* + * Update in-meory device->total_bytes, so that at trans commit time, + * super->dev_item will also get updated + */ + device->total_bytes = new_size; + btrfs_init_path(&path); + + /* Update device item in chunk tree */ + trans = btrfs_start_transaction(chunk_root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + error("failed to start transaction: %d (%s)", ret, + strerror(-ret)); + return ret; + } + key.objectid = BTRFS_DEV_ITEMS_OBJECTID; + key.type = BTRFS_DEV_ITEM_KEY; + key.offset = device->devid; + + ret = btrfs_search_slot(trans, chunk_root, &key, &path, 0, 1); + if (ret < 0) + goto err; + if (ret > 0) + ret = -ENOENT; + di = btrfs_item_ptr(path.nodes[0], path.slots[0], + struct btrfs_dev_item); + btrfs_set_device_total_bytes(path.nodes[0], di, new_size); + btrfs_mark_buffer_dirty(path.nodes[0]); + + /* + * Update super->total_bytes, since it's only used for --rootdir, + * there is only one device, just use the @new_size. + */ + btrfs_set_super_total_bytes(fs_info->super_copy, new_size); + + /* + * Commit transaction to reflect the updated super->total_bytes and + * super->dev_item + */ + ret = btrfs_commit_transaction(trans, chunk_root); + if (ret < 0) + error("failed to commit current transaction: %d (%s)", + ret, strerror(-ret)); + btrfs_release_path(&path); + return ret; + +err: + btrfs_release_path(&path); + /* + * Committing the transaction here won't cause problems since the fs + * still has an invalid magic number, and something wrong already + * happened, we don't care the return value anyway. + */ + btrfs_commit_transaction(trans, chunk_root); + return ret; +} + +int btrfs_mkfs_shrink_fs(struct btrfs_fs_info *fs_info, u64 *new_size_ret) +{ + u64 new_size; + struct btrfs_device *device; + struct list_head *cur; + int nr_devs = 0; + int ret; + + list_for_each(cur, &fs_info->fs_devices->devices) + nr_devs++; + + if (nr_devs > 1) { + error("cannot shrink fs with more than 1 device"); + return -ENOTTY; + } + + ret = get_device_extent_end(fs_info, 1, &new_size); + if (ret < 0) { + error("failed to get minimal device size: %d (%s)", + ret, strerror(-ret)); + return ret; + } + + BUG_ON(!IS_ALIGNED(new_size, fs_info->sectorsize)); + + device = list_entry(fs_info->fs_devices->devices.next, + struct btrfs_device, dev_list); + ret = set_device_size(fs_info, device, new_size); + if (ret < 0) + return ret; + if (new_size_ret) + *new_size_ret = new_size; + return ret; +} -- cgit v1.2.3