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-rw-r--r--fs/btrfs/inode.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index da2a5e90a1..2e3fcad5a8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -162,6 +162,115 @@ int __btrfs_readlink(const struct __btrfs_root *root, u64 inr, char *target)
return 0;
}
+static int lookup_root_ref(struct btrfs_fs_info *fs_info,
+ u64 rootid, u64 *root_ret, u64 *dir_ret)
+{
+ struct btrfs_root *root = fs_info->tree_root;
+ struct btrfs_root_ref *root_ref;
+ struct btrfs_path path;
+ struct btrfs_key key;
+ int ret;
+
+ btrfs_init_path(&path);
+ key.objectid = rootid;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
+ key.offset = (u64)-1;
+
+ ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+ if (ret < 0)
+ return ret;
+ /* Should not happen */
+ if (ret == 0) {
+ ret = -EUCLEAN;
+ goto out;
+ }
+ ret = btrfs_previous_item(root, &path, rootid, BTRFS_ROOT_BACKREF_KEY);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ root_ref = btrfs_item_ptr(path.nodes[0], path.slots[0],
+ struct btrfs_root_ref);
+ *root_ret = key.offset;
+ *dir_ret = btrfs_root_ref_dirid(path.nodes[0], root_ref);
+out:
+ btrfs_release_path(&path);
+ return ret;
+}
+
+/*
+ * To get the parent inode of @ino of @root.
+ *
+ * @root_ret and @ino_ret will be filled.
+ *
+ * NOTE: This function is not reliable. It can only get one parent inode.
+ * The get the proper parent inode, we need a full VFS inodes stack to
+ * resolve properly.
+ */
+static int get_parent_inode(struct btrfs_root *root, u64 ino,
+ struct btrfs_root **root_ret, u64 *ino_ret)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_path path;
+ struct btrfs_key key;
+ int ret;
+
+ if (ino == BTRFS_FIRST_FREE_OBJECTID) {
+ u64 parent_root = -1;
+
+ /* It's top level already, no more parent */
+ if (root->root_key.objectid == BTRFS_FS_TREE_OBJECTID) {
+ *root_ret = fs_info->fs_root;
+ *ino_ret = BTRFS_FIRST_FREE_OBJECTID;
+ return 0;
+ }
+
+ ret = lookup_root_ref(fs_info, root->root_key.objectid,
+ &parent_root, ino_ret);
+ if (ret < 0)
+ return ret;
+
+ key.objectid = parent_root;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+ *root_ret = btrfs_read_fs_root(fs_info, &key);
+ if (IS_ERR(*root_ret))
+ return PTR_ERR(*root_ret);
+
+ return 0;
+ }
+
+ btrfs_init_path(&path);
+ key.objectid = ino;
+ key.type = BTRFS_INODE_REF_KEY;
+ key.offset = (u64)-1;
+
+ ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+ if (ret < 0)
+ return ret;
+ /* Should not happen */
+ if (ret == 0) {
+ ret = -EUCLEAN;
+ goto out;
+ }
+ ret = btrfs_previous_item(root, &path, ino, BTRFS_INODE_REF_KEY);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ *root_ret = root;
+ *ino_ret = key.offset;
+out:
+ btrfs_release_path(&path);
+ return ret;
+}
+
/* inr must be a directory (for regular files with multiple hard links this
function returns only one of the parents of the file) */
static u64 __get_parent_inode(struct __btrfs_root *root, u64 inr,
@@ -240,6 +349,147 @@ static inline const char *skip_current_directories(const char *cur)
return cur;
}
+/*
+ * Resolve one filename of @ino of @root.
+ *
+ * key_ret: The child key (either INODE_ITEM or ROOT_ITEM type)
+ * type_ret: BTRFS_FT_* of the child inode.
+ *
+ * Return 0 with above members filled.
+ * Return <0 for error.
+ */
+static int resolve_one_filename(struct btrfs_root *root, u64 ino,
+ const char *name, int namelen,
+ struct btrfs_key *key_ret, u8 *type_ret)
+{
+ struct btrfs_dir_item *dir_item;
+ struct btrfs_path path;
+ int ret = 0;
+
+ btrfs_init_path(&path);
+
+ dir_item = btrfs_lookup_dir_item(NULL, root, &path, ino, name,
+ namelen, 0);
+ if (IS_ERR(dir_item)) {
+ ret = PTR_ERR(dir_item);
+ goto out;
+ }
+
+ btrfs_dir_item_key_to_cpu(path.nodes[0], dir_item, key_ret);
+ *type_ret = btrfs_dir_type(path.nodes[0], dir_item);
+out:
+ btrfs_release_path(&path);
+ return ret;
+}
+
+/*
+ * Resolve a full path @filename. The start point is @ino of @root.
+ *
+ * The result will be filled into @root_ret, @ino_ret and @type_ret.
+ */
+int btrfs_lookup_path(struct btrfs_root *root, u64 ino, const char *filename,
+ struct btrfs_root **root_ret, u64 *ino_ret,
+ u8 *type_ret, int symlink_limit)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *next_root;
+ struct btrfs_key key;
+ const char *cur = filename;
+ u64 next_ino;
+ u8 next_type;
+ u8 type;
+ int len;
+ int ret = 0;
+
+ /* If the path is absolute path, also search from fs root */
+ if (*cur == '/') {
+ root = fs_info->fs_root;
+ ino = btrfs_root_dirid(&root->root_item);
+ type = BTRFS_FT_DIR;
+ }
+
+ while (*cur != '\0') {
+ cur = skip_current_directories(cur);
+
+ len = next_length(cur);
+ if (len > BTRFS_NAME_LEN) {
+ error("%s: Name too long at \"%.*s\"", __func__,
+ BTRFS_NAME_LEN, cur);
+ return -ENAMETOOLONG;
+ }
+
+ if (len == 1 && cur[0] == '.')
+ break;
+
+ if (len == 2 && cur[0] == '.' && cur[1] == '.') {
+ /* Go one level up */
+ ret = get_parent_inode(root, ino, &next_root, &next_ino);
+ if (ret < 0)
+ return ret;
+ root = next_root;
+ ino = next_ino;
+ goto next;
+ }
+
+ if (!*cur)
+ break;
+
+ ret = resolve_one_filename(root, ino, cur, len, &key, &type);
+ if (ret < 0)
+ return ret;
+
+ if (key.type == BTRFS_ROOT_ITEM_KEY) {
+ /* Child inode is a subvolume */
+
+ next_root = btrfs_read_fs_root(fs_info, &key);
+ if (IS_ERR(next_root))
+ return PTR_ERR(next_root);
+ root = next_root;
+ ino = btrfs_root_dirid(&root->root_item);
+ } else if (type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
+ /* Child inode is a symlink */
+
+ char *target;
+
+ if (symlink_limit == 0) {
+ error("%s: Too much symlinks!", __func__);
+ return -EMLINK;
+ }
+ target = malloc(fs_info->sectorsize);
+ if (!target)
+ return -ENOMEM;
+ ret = btrfs_readlink(root, key.objectid, target);
+ if (ret < 0) {
+ free(target);
+ return ret;
+ }
+ target[ret] = '\0';
+
+ ret = btrfs_lookup_path(root, ino, target, &next_root,
+ &next_ino, &next_type,
+ symlink_limit);
+ if (ret < 0)
+ return ret;
+ root = next_root;
+ ino = next_ino;
+ type = next_type;
+ } else {
+ /* Child inode is an inode */
+ ino = key.objectid;
+ }
+next:
+ cur += len;
+ }
+
+ if (!ret) {
+ *root_ret = root;
+ *ino_ret = ino;
+ *type_ret = type;
+ }
+
+ return ret;
+}
+
u64 __btrfs_lookup_path(struct __btrfs_root *root, u64 inr, const char *path,
u8 *type_p, struct btrfs_inode_item *inode_item_p,
int symlink_limit)
generated by cgit v1.2.3 (git 2.0.4) at 2024-06-23 03:05:53 +0000