On 04/18/2018 01:21 PM, Qu Wenruo wrote:
On 2018年03月27日 15:06, Lu Fengqi wrote:The function will create lost+found directory, link the deleted subvolume specified by the subvol_id to the directory, update the information of root_item and cleanup the associated orphan item. Signed-off-by: Lu Fengqi <lufq.f...@cn.fujitsu.com> --- undelete-subvol.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/undelete-subvol.c b/undelete-subvol.c index 781057df2b84..9243e35545c5 100644 --- a/undelete-subvol.c +++ b/undelete-subvol.c @@ -106,3 +106,79 @@ out: btrfs_release_path(&path); return ret; } + +/* + * Recover a subvolume specified by subvol_id, and link it to the lost+found + * directory. + * + * @root: the root of the root tree.In that case, @fs_info would case less confusion. Otherwise looks good. Reviewed-by: Qu Wenruo <w...@suse.com>
Make sense. -- Thanks, Lu
Thanks, Qu+ * @subvol_id: specify the subvolume which will be linked, and also be the part + * of the subvolume name. + * + * Return 0 if no error occurred. + */ +static int link_subvol_to_lostfound(struct btrfs_root *root, u64 subvol_id) +{ + struct btrfs_trans_handle *trans; + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_root *fs_root = fs_info->fs_root; + char buf[BTRFS_NAME_LEN + 1] = {0}; /* 1 for snprintf null */ + char *dir_name = "lost+found"; + u64 lost_found_ino = 0; + u32 mode = 0700; + int ret; + + /* + * For link subvolume to lost+found, + * 2 for parent(256)'s dir_index and dir_item + * 2 for lost+found dir's inode_item and inode_ref + * 2 for lost+found dir's dir_index and dir_item for the subvolume + * 2 for the subvolume's root_ref and root_backref + */ + trans = btrfs_start_transaction(fs_root, 8); + if (IS_ERR(trans)) { + error("unable to start transaction"); + ret = PTR_ERR(trans); + goto out; + } + + /* Create lost+found directory */ + ret = btrfs_mkdir(trans, fs_root, dir_name, strlen(dir_name), + BTRFS_FIRST_FREE_OBJECTID, &lost_found_ino, + mode); + if (ret < 0) { + error("failed to create '%s' dir: %d", dir_name, ret); + goto out; + } + + /* Link the subvolume to lost+found directory */ + snprintf(buf, BTRFS_NAME_LEN + 1, "sub%llu", subvol_id); + ret = btrfs_link_subvol(trans, fs_root, buf, subvol_id, lost_found_ino, + false); + if (ret) { + error("failed to link the subvol %llu: %d", subvol_id, ret); + goto out; + } + + /* Clear root flags BTRFS_ROOT_SUBVOL_DEAD and increase root refs */ + ret = recover_dead_root(trans, root, subvol_id); + if (ret) + goto out; + + /* Delete the orphan item after undeletion is completed. */ + ret = btrfs_del_orphan_item(trans, root, subvol_id); + if (ret) { + error("failed to delete the orphan_item for %llu: %d", + subvol_id, ret); + goto out; + } + + ret = btrfs_commit_transaction(trans, fs_root); + if (ret) { + error("transaction commit failed: %d", ret); + goto out; + } + +out: + return ret; +}
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