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      1 // SPDX-License-Identifier: GPL-2.0+
      2 /*
      3  * BTRFS filesystem implementation for U-Boot
      4  *
      5  * 2017 Marek Behun, CZ.NIC, marek.behun (at) nic.cz
      6  */
      7 
      8 #include "btrfs.h"
      9 #include <malloc.h>
     10 
     11 static int get_subvol_name(u64 subvolid, char *name, int max_len)
     12 {
     13 	struct btrfs_root_ref rref;
     14 	struct btrfs_inode_ref iref;
     15 	struct btrfs_root root;
     16 	u64 dir;
     17 	char tmp[max(BTRFS_VOL_NAME_MAX, BTRFS_NAME_MAX)];
     18 	char *ptr;
     19 
     20 	ptr = name + max_len - 1;
     21 	*ptr = '\0';
     22 
     23 	while (subvolid != BTRFS_FS_TREE_OBJECTID) {
     24 		subvolid = btrfs_lookup_root_ref(subvolid, &rref, tmp);
     25 
     26 		if (subvolid == -1ULL)
     27 			return -1;
     28 
     29 		ptr -= rref.name_len + 1;
     30 		if (ptr < name)
     31 			goto too_long;
     32 
     33 		memcpy(ptr + 1, tmp, rref.name_len);
     34 		*ptr = '/';
     35 
     36 		if (btrfs_find_root(subvolid, &root, NULL))
     37 			return -1;
     38 
     39 		dir = rref.dirid;
     40 
     41 		while (dir != BTRFS_FIRST_FREE_OBJECTID) {
     42 			dir = btrfs_lookup_inode_ref(&root, dir, &iref, tmp);
     43 
     44 			if (dir == -1ULL)
     45 				return -1;
     46 
     47 			ptr -= iref.name_len + 1;
     48 			if (ptr < name)
     49 				goto too_long;
     50 
     51 			memcpy(ptr + 1, tmp, iref.name_len);
     52 			*ptr = '/';
     53 		}
     54 	}
     55 
     56 	if (ptr == name + max_len - 1) {
     57 		name[0] = '/';
     58 		name[1] = '\0';
     59 	} else {
     60 		memmove(name, ptr, name + max_len - ptr);
     61 	}
     62 
     63 	return 0;
     64 
     65 too_long:
     66 	printf("%s: subvolume name too long\n", __func__);
     67 	return -1;
     68 }
     69 
     70 u64 btrfs_get_default_subvol_objectid(void)
     71 {
     72 	struct btrfs_dir_item item;
     73 
     74 	if (btrfs_lookup_dir_item(&btrfs_info.tree_root,
     75 				  btrfs_info.sb.root_dir_objectid, "default", 7,
     76 				  &item))
     77 		return BTRFS_FS_TREE_OBJECTID;
     78 	return item.location.objectid;
     79 }
     80 
     81 static void list_subvols(u64 tree, char *nameptr, int max_name_len, int level)
     82 {
     83 	struct btrfs_key key, *found_key;
     84 	struct btrfs_path path;
     85 	struct btrfs_root_ref *ref;
     86 	int res;
     87 
     88 	key.objectid = tree;
     89 	key.type = BTRFS_ROOT_REF_KEY;
     90 	key.offset = 0;
     91 
     92 	if (btrfs_search_tree(&btrfs_info.tree_root, &key, &path))
     93 		return;
     94 
     95 	do {
     96 		found_key = btrfs_path_leaf_key(&path);
     97 		if (btrfs_comp_keys_type(&key, found_key))
     98 			break;
     99 
    100 		ref = btrfs_path_item_ptr(&path, struct btrfs_root_ref);
    101 		btrfs_root_ref_to_cpu(ref);
    102 
    103 		printf("ID %llu parent %llu name ", found_key->offset, tree);
    104 		if (nameptr && !get_subvol_name(found_key->offset, nameptr,
    105 						max_name_len))
    106 			printf("%s\n", nameptr);
    107 		else
    108 			printf("%.*s\n", (int) ref->name_len,
    109 			       (const char *) (ref + 1));
    110 
    111 		if (level > 0)
    112 			list_subvols(found_key->offset, nameptr, max_name_len,
    113 				     level - 1);
    114 		else
    115 			printf("%s: Too much recursion, maybe skipping some "
    116 			       "subvolumes\n", __func__);
    117 	} while (!(res = btrfs_next_slot(&path)));
    118 
    119 	btrfs_free_path(&path);
    120 }
    121 
    122 void btrfs_list_subvols(void)
    123 {
    124 	char *nameptr = malloc(4096);
    125 
    126 	list_subvols(BTRFS_FS_TREE_OBJECTID, nameptr, nameptr ? 4096 : 0, 40);
    127 
    128 	if (nameptr)
    129 		free(nameptr);
    130 }
    131