1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include "ctree.h" 20 #include "disk-io.h" 21 #include "transaction.h" 22 23 static int find_name_in_backref(struct btrfs_path *path, const char *name, 24 int name_len, struct btrfs_inode_ref **ref_ret) 25 { 26 struct extent_buffer *leaf; 27 struct btrfs_inode_ref *ref; 28 unsigned long ptr; 29 unsigned long name_ptr; 30 u32 item_size; 31 u32 cur_offset = 0; 32 int len; 33 34 leaf = path->nodes[0]; 35 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 36 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 37 while (cur_offset < item_size) { 38 ref = (struct btrfs_inode_ref *)(ptr + cur_offset); 39 len = btrfs_inode_ref_name_len(leaf, ref); 40 name_ptr = (unsigned long)(ref + 1); 41 cur_offset += len + sizeof(*ref); 42 if (len != name_len) 43 continue; 44 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) { 45 *ref_ret = ref; 46 return 1; 47 } 48 } 49 return 0; 50 } 51 52 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans, 53 struct btrfs_root *root, 54 const char *name, int name_len, 55 u64 inode_objectid, u64 ref_objectid, u64 *index) 56 { 57 struct btrfs_path *path; 58 struct btrfs_key key; 59 struct btrfs_inode_ref *ref; 60 struct extent_buffer *leaf; 61 unsigned long ptr; 62 unsigned long item_start; 63 u32 item_size; 64 u32 sub_item_len; 65 int ret; 66 int del_len = name_len + sizeof(*ref); 67 68 key.objectid = inode_objectid; 69 key.offset = ref_objectid; 70 btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY); 71 72 path = btrfs_alloc_path(); 73 if (!path) 74 return -ENOMEM; 75 76 path->leave_spinning = 1; 77 78 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 79 if (ret > 0) { 80 ret = -ENOENT; 81 goto out; 82 } else if (ret < 0) { 83 goto out; 84 } 85 if (!find_name_in_backref(path, name, name_len, &ref)) { 86 ret = -ENOENT; 87 goto out; 88 } 89 leaf = path->nodes[0]; 90 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 91 92 if (index) 93 *index = btrfs_inode_ref_index(leaf, ref); 94 95 if (del_len == item_size) { 96 ret = btrfs_del_item(trans, root, path); 97 goto out; 98 } 99 ptr = (unsigned long)ref; 100 sub_item_len = name_len + sizeof(*ref); 101 item_start = btrfs_item_ptr_offset(leaf, path->slots[0]); 102 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len, 103 item_size - (ptr + sub_item_len - item_start)); 104 ret = btrfs_truncate_item(trans, root, path, 105 item_size - sub_item_len, 1); 106 BUG_ON(ret); 107 out: 108 btrfs_free_path(path); 109 return ret; 110 } 111 112 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans, 113 struct btrfs_root *root, 114 const char *name, int name_len, 115 u64 inode_objectid, u64 ref_objectid, u64 index) 116 { 117 struct btrfs_path *path; 118 struct btrfs_key key; 119 struct btrfs_inode_ref *ref; 120 unsigned long ptr; 121 int ret; 122 int ins_len = name_len + sizeof(*ref); 123 124 key.objectid = inode_objectid; 125 key.offset = ref_objectid; 126 btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY); 127 128 path = btrfs_alloc_path(); 129 if (!path) 130 return -ENOMEM; 131 132 path->leave_spinning = 1; 133 ret = btrfs_insert_empty_item(trans, root, path, &key, 134 ins_len); 135 if (ret == -EEXIST) { 136 u32 old_size; 137 138 if (find_name_in_backref(path, name, name_len, &ref)) 139 goto out; 140 141 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]); 142 ret = btrfs_extend_item(trans, root, path, ins_len); 143 BUG_ON(ret); 144 ref = btrfs_item_ptr(path->nodes[0], path->slots[0], 145 struct btrfs_inode_ref); 146 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size); 147 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len); 148 btrfs_set_inode_ref_index(path->nodes[0], ref, index); 149 ptr = (unsigned long)(ref + 1); 150 ret = 0; 151 } else if (ret < 0) { 152 if (ret == -EOVERFLOW) 153 ret = -EMLINK; 154 goto out; 155 } else { 156 ref = btrfs_item_ptr(path->nodes[0], path->slots[0], 157 struct btrfs_inode_ref); 158 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len); 159 btrfs_set_inode_ref_index(path->nodes[0], ref, index); 160 ptr = (unsigned long)(ref + 1); 161 } 162 write_extent_buffer(path->nodes[0], name, ptr, name_len); 163 btrfs_mark_buffer_dirty(path->nodes[0]); 164 165 out: 166 btrfs_free_path(path); 167 return ret; 168 } 169 170 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans, 171 struct btrfs_root *root, 172 struct btrfs_path *path, u64 objectid) 173 { 174 struct btrfs_key key; 175 int ret; 176 key.objectid = objectid; 177 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); 178 key.offset = 0; 179 180 ret = btrfs_insert_empty_item(trans, root, path, &key, 181 sizeof(struct btrfs_inode_item)); 182 return ret; 183 } 184 185 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root 186 *root, struct btrfs_path *path, 187 struct btrfs_key *location, int mod) 188 { 189 int ins_len = mod < 0 ? -1 : 0; 190 int cow = mod != 0; 191 int ret; 192 int slot; 193 struct extent_buffer *leaf; 194 struct btrfs_key found_key; 195 196 ret = btrfs_search_slot(trans, root, location, path, ins_len, cow); 197 if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY && 198 location->offset == (u64)-1 && path->slots[0] != 0) { 199 slot = path->slots[0] - 1; 200 leaf = path->nodes[0]; 201 btrfs_item_key_to_cpu(leaf, &found_key, slot); 202 if (found_key.objectid == location->objectid && 203 btrfs_key_type(&found_key) == btrfs_key_type(location)) { 204 path->slots[0]--; 205 return 0; 206 } 207 } 208 return ret; 209 } 210