git.sur5r.net Git - u-boot/blob - fs/btrfs/subvolume.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * BTRFS filesystem implementation for U-Boot
   4  *
   5  * 2017 Marek Behun, CZ.NIC, marek.behun@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 }