1 files changed, 207 insertions, 103 deletions

diff --git a/fs/btrfs/subvolume.c b/fs/btrfs/subvolume.c
index 06e54f3310..2815673bcd 100644
--- a/fs/btrfs/subvolume.c
+++ b/fs/btrfs/subvolume.c
@@ -5,126 +5,230 @@
  * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
  */
 
-#include "btrfs.h"
 #include <malloc.h>
+#include "ctree.h"
+#include "btrfs.h"
+#include "disk-io.h"
 
-static int get_subvol_name(u64 subvolid, char *name, int max_len)
+/*
+ * Resolve the path of ino inside subvolume @root into @path_ret.
+ *
+ * @path_ret must be at least PATH_MAX size.
+ */
+static int get_path_in_subvol(struct btrfs_root *root, u64 ino, char *path_ret)
 {
-	struct btrfs_root_ref rref;
-	struct btrfs_inode_ref iref;
-	struct btrfs_root root;
-	u64 dir;
-	char tmp[max(BTRFS_VOL_NAME_MAX, BTRFS_NAME_MAX)];
-	char *ptr;
-
-	ptr = name + max_len - 1;
-	*ptr = '\0';
-
-	while (subvolid != BTRFS_FS_TREE_OBJECTID) {
-		subvolid = btrfs_lookup_root_ref(subvolid, &rref, tmp);
-
-		if (subvolid == -1ULL)
-			return -1;
-
-		ptr -= rref.name_len + 1;
-		if (ptr < name)
-			goto too_long;
-
-		memcpy(ptr + 1, tmp, rref.name_len);
-		*ptr = '/';
-
-		if (btrfs_find_root(subvolid, &root, NULL))
-			return -1;
-
-		dir = rref.dirid;
-
-		while (dir != BTRFS_FIRST_FREE_OBJECTID) {
-			dir = btrfs_lookup_inode_ref(&root, dir, &iref, tmp);
-
-			if (dir == -1ULL)
-				return -1;
-
-			ptr -= iref.name_len + 1;
-			if (ptr < name)
-				goto too_long;
-
-			memcpy(ptr + 1, tmp, iref.name_len);
-			*ptr = '/';
+	struct btrfs_path path;
+	struct btrfs_key key;
+	char *tmp;
+	u64 cur = ino;
+	int ret = 0;
+
+	tmp = malloc(PATH_MAX);
+	if (!tmp)
+		return -ENOMEM;
+	tmp[0] = '\0';
+
+	btrfs_init_path(&path);
+	while (cur != BTRFS_FIRST_FREE_OBJECTID) {
+		struct btrfs_inode_ref *iref;
+		int name_len;
+
+		btrfs_release_path(&path);
+		key.objectid = cur;
+		key.type = BTRFS_INODE_REF_KEY;
+		key.offset = (u64)-1;
+
+		ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+		/* Impossible */
+		if (ret == 0)
+			ret = -EUCLEAN;
+		if (ret < 0)
+			goto out;
+		ret = btrfs_previous_item(root, &path, cur,
+					  BTRFS_INODE_REF_KEY);
+		if (ret > 0)
+			ret = -ENOENT;
+		if (ret < 0)
+			goto out;
+
+		strncpy(tmp, path_ret, PATH_MAX);
+		iref = btrfs_item_ptr(path.nodes[0], path.slots[0],
+				      struct btrfs_inode_ref);
+		name_len = btrfs_inode_ref_name_len(path.nodes[0],
+						    iref);
+		if (name_len > BTRFS_NAME_LEN) {
+			ret = -ENAMETOOLONG;
+			goto out;
 		}
+		read_extent_buffer(path.nodes[0], path_ret,
+				   (unsigned long)(iref + 1), name_len);
+		path_ret[name_len] = '/';
+		path_ret[name_len + 1] = '\0';
+		strncat(path_ret, tmp, PATH_MAX);
+
+		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+		cur = key.offset;
 	}
-
-	if (ptr == name + max_len - 1) {
-		name[0] = '/';
-		name[1] = '\0';
-	} else {
-		memmove(name, ptr, name + max_len - ptr);
-	}
-
-	return 0;
-
-too_long:
-	printf("%s: subvolume name too long\n", __func__);
-	return -1;
+out:
+	btrfs_release_path(&path);
+	free(tmp);
+	return ret;
 }
 
-u64 btrfs_get_default_subvol_objectid(void)
+static int list_one_subvol(struct btrfs_root *root, char *path_ret)
 {
-	struct btrfs_dir_item item;
-
-	if (btrfs_lookup_dir_item(&btrfs_info.tree_root,
-				  btrfs_info.sb.root_dir_objectid, "default", 7,
-				  &item))
-		return BTRFS_FS_TREE_OBJECTID;
-	return item.location.objectid;
+	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 void list_subvols(u64 tree, char *nameptr, int max_name_len, int level)
+static int list_subvolums(struct btrfs_fs_info *fs_info)
 {
-	struct btrfs_key key, *found_key;
+	struct btrfs_root *tree_root = fs_info->tree_root;
+	struct btrfs_root *root;
 	struct btrfs_path path;
-	struct btrfs_root_ref *ref;
-	int res;
-
-	key.objectid = tree;
-	key.type = BTRFS_ROOT_REF_KEY;
+	struct btrfs_key key;
+	char *result;
+	int ret = 0;
+
+	result = malloc(PATH_MAX);
+	if (!result)
+		return -ENOMEM;
+
+	ret = list_one_subvol(fs_info->fs_root, result);
+	if (ret < 0)
+		goto out;
+	root = fs_info->fs_root;
+	printf("ID %llu gen %llu path %.*s\n",
+		root->root_key.objectid, btrfs_root_generation(&root->root_item),
+		PATH_MAX, result);
+
+	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+	key.type = BTRFS_ROOT_ITEM_KEY;
 	key.offset = 0;
-
-	if (btrfs_search_tree(&btrfs_info.tree_root, &key, &path))
-		return;
-
-	do {
-		found_key = btrfs_path_leaf_key(&path);
-		if (btrfs_comp_keys_type(&key, found_key))
+	btrfs_init_path(&path);
+	ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
+	if (ret < 0)
+		goto out;
+	while (1) {
+		if (path.slots[0] >= btrfs_header_nritems(path.nodes[0]))
+			goto next;
+
+		btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+		if (key.objectid > BTRFS_LAST_FREE_OBJECTID)
 			break;
-
-		ref = btrfs_path_item_ptr(&path, struct btrfs_root_ref);
-		btrfs_root_ref_to_cpu(ref);
-
-		printf("ID %llu parent %llu name ", found_key->offset, tree);
-		if (nameptr && !get_subvol_name(found_key->offset, nameptr,
-						max_name_len))
-			printf("%s\n", nameptr);
-		else
-			printf("%.*s\n", (int) ref->name_len,
-			       (const char *) (ref + 1));
-
-		if (level > 0)
-			list_subvols(found_key->offset, nameptr, max_name_len,
-				     level - 1);
-		else
-			printf("%s: Too much recursion, maybe skipping some "
-			       "subvolumes\n", __func__);
-	} while (!(res = btrfs_next_slot(&path)));
-
-	btrfs_free_path(&path);
+		if (key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
+		    key.type != BTRFS_ROOT_ITEM_KEY)
+			goto next;
+		key.offset = (u64)-1;
+		root = btrfs_read_fs_root(fs_info, &key);
+		if (IS_ERR(root)) {
+			ret = PTR_ERR(root);
+			if (ret == -ENOENT)
+				goto next;
+		}
+		ret = list_one_subvol(root, result);
+		if (ret < 0)
+			goto out;
+		printf("ID %llu gen %llu path %.*s\n",
+			root->root_key.objectid,
+			btrfs_root_generation(&root->root_item),
+			PATH_MAX, result);
+next:
+		ret = btrfs_next_item(tree_root, &path);
+		if (ret < 0)
+			goto out;
+		if (ret > 0) {
+			ret = 0;
+			break;
+		}
+	}
+out:
+	free(result);
+	return ret;
 }
 
 void btrfs_list_subvols(void)
 {
-	char *nameptr = malloc(4096);
+	struct btrfs_fs_info *fs_info = current_fs_info;
+	int ret;
 
-	list_subvols(BTRFS_FS_TREE_OBJECTID, nameptr, nameptr ? 4096 : 0, 40);
-
-	if (nameptr)
-		free(nameptr);
+	if (!fs_info)
+		return;
+	ret = list_subvolums(fs_info);
+	if (ret < 0)
+		error("failed to list subvolume: %d", ret);
 }