This patch introduces a new function, list_one_subvol(), which will resolve the path to FS_TREE of one subvolume.
Signed-off-by: Qu Wenruo wqu@suse.com --- fs/btrfs/subvolume.c | 81 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+)
diff --git a/fs/btrfs/subvolume.c b/fs/btrfs/subvolume.c index b446e729cd89..258c3dafef60 100644 --- a/fs/btrfs/subvolume.c +++ b/fs/btrfs/subvolume.c @@ -8,6 +8,7 @@ #include <malloc.h> #include "ctree.h" #include "btrfs.h" +#include "disk-io.h"
/* * Resolve the path of ino inside subvolume @root into @path_ret. @@ -74,6 +75,86 @@ out: return ret; }
+static int list_one_subvol(struct btrfs_root *root, char *path_ret) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_root *tree_root = fs_info->tree_root; + struct btrfs_path path; + struct btrfs_key key; + char *tmp; + u64 cur = root->root_key.objectid; + int ret = 0; + + tmp = malloc(PATH_MAX); + if (!tmp) + return -ENOMEM; + tmp[0] = '\0'; + path_ret[0] = '\0'; + btrfs_init_path(&path); + while (cur != BTRFS_FS_TREE_OBJECTID) { + struct btrfs_root_ref *rr; + struct btrfs_key location; + int name_len; + u64 ino; + + key.objectid = cur; + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = (u64)-1; + btrfs_release_path(&path); + + ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0); + if (ret == 0) + ret = -EUCLEAN; + if (ret < 0) + goto out; + ret = btrfs_previous_item(tree_root, &path, cur, + BTRFS_ROOT_BACKREF_KEY); + if (ret > 0) + ret = -ENOENT; + if (ret < 0) + goto out; + + /* Get the subvolume name */ + rr = btrfs_item_ptr(path.nodes[0], path.slots[0], + struct btrfs_root_ref); + strncpy(tmp, path_ret, PATH_MAX); + name_len = btrfs_root_ref_name_len(path.nodes[0], rr); + if (name_len > BTRFS_NAME_LEN) { + ret = -ENAMETOOLONG; + goto out; + } + ino = btrfs_root_ref_dirid(path.nodes[0], rr); + read_extent_buffer(path.nodes[0], path_ret, + (unsigned long)(rr + 1), name_len); + path_ret[name_len] = '/'; + path_ret[name_len + 1] = '\0'; + strncat(path_ret, tmp, PATH_MAX); + + /* Get the path inside the parent subvolume */ + btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]); + location.objectid = key.offset; + location.type = BTRFS_ROOT_ITEM_KEY; + location.offset = (u64)-1; + root = btrfs_read_fs_root(fs_info, &location); + if (IS_ERR(root)) { + ret = PTR_ERR(root); + goto out; + } + ret = get_path_in_subvol(root, ino, path_ret); + if (ret < 0) + goto out; + cur = key.offset; + } + /* Add the leading '/' */ + strncpy(tmp, path_ret, PATH_MAX); + strncpy(path_ret, "/", PATH_MAX); + strncat(path_ret, tmp, PATH_MAX); +out: + btrfs_release_path(&path); + free(tmp); + return ret; +} + static int get_subvol_name(u64 subvolid, char *name, int max_len) { struct btrfs_root_ref rref;