inode-item.c

   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 #include "hash.h"
  23
  24 static int find_name_in_backref(struct btrfs_path *path, const char * name,
  25                          int name_len, struct btrfs_inode_ref **ref_ret)
  26 {
  27         struct extent_buffer *leaf;
  28         struct btrfs_inode_ref *ref;
  29         unsigned long ptr;
  30         unsigned long name_ptr;
  31         u32 item_size;
  32         u32 cur_offset = 0;
  33         int len;
  34
  35         leaf = path->nodes[0];
  36         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
  37         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
  38         while (cur_offset < item_size) {
  39                 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
  40                 len = btrfs_inode_ref_name_len(leaf, ref);
  41                 name_ptr = (unsigned long)(ref + 1);
  42                 cur_offset += len + sizeof(*ref);
  43                 if (len != name_len)
  44                         continue;
  45                 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
  46                         *ref_ret = ref;
  47                         return 1;
  48                 }
  49         }
  50         return 0;
  51 }
  52
  53 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
  54                            struct btrfs_root *root,
  55                            const char *name, int name_len,
  56                            u64 inode_objectid, u64 ref_objectid, u64 index)
  57 {
  58         struct btrfs_path *path;
  59         struct btrfs_key key;
  60         struct btrfs_inode_ref *ref;
  61         unsigned long ptr;
  62         int ret;
  63         int ins_len = name_len + sizeof(*ref);
  64
  65         key.objectid = inode_objectid;
  66         key.offset = ref_objectid;
  67         key.type = BTRFS_INODE_REF_KEY;
  68
  69         path = btrfs_alloc_path();
  70         if (!path)
  71                 return -ENOMEM;
  72
  73         ret = btrfs_insert_empty_item(trans, root, path, &key,
  74                                       ins_len);
  75         if (ret == -EEXIST) {
  76                 u32 old_size;
  77
  78                 if (find_name_in_backref(path, name, name_len, &ref))
  79                         goto out;
  80
  81                 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
  82                 ret = btrfs_extend_item(root, path, ins_len);
  83                 BUG_ON(ret);
  84                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  85                                      struct btrfs_inode_ref);
  86                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
  87                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
  88                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
  89                 ptr = (unsigned long)(ref + 1);
  90                 ret = 0;
  91         } else if (ret < 0) {
  92                 if (ret == -EOVERFLOW)
  93                         ret = -EMLINK;
  94                 goto out;
  95         } else {
  96                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
  97                                      struct btrfs_inode_ref);
  98                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
  99                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 100                 ptr = (unsigned long)(ref + 1);
 101         }
 102         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 103         btrfs_mark_buffer_dirty(path->nodes[0]);
 104
 105 out:
 106         btrfs_free_path(path);
 107
 108         if (ret == -EMLINK) {
 109                 if (btrfs_fs_incompat(root->fs_info, EXTENDED_IREF))
 110                         ret = btrfs_insert_inode_extref(trans, root, name,
 111                                                         name_len,
 112                                                         inode_objectid,
 113                                                         ref_objectid, index);
 114         }
 115         return ret;
 116 }
 117
 118 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 119                        *root, struct btrfs_path *path,
 120                        struct btrfs_key *location, int mod)
 121 {
 122         int ins_len = mod < 0 ? -1 : 0;
 123         int cow = mod != 0;
 124         int ret;
 125         int slot;
 126         struct extent_buffer *leaf;
 127         struct btrfs_key found_key;
 128
 129         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
 130         if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
 131             location->offset == (u64)-1 && path->slots[0] != 0) {
 132                 slot = path->slots[0] - 1;
 133                 leaf = path->nodes[0];
 134                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 135                 if (found_key.objectid == location->objectid &&
 136                     found_key.type == location->type) {
 137                         path->slots[0]--;
 138                         return 0;
 139                 }
 140         }
 141         return ret;
 142 }
 143
 144 int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 145                        *root, u64 objectid, struct btrfs_inode_item
 146                        *inode_item)
 147 {
 148         int ret;
 149         struct btrfs_key key;
 150
 151         key.objectid = objectid;
 152         key.type = BTRFS_INODE_ITEM_KEY;
 153         key.offset = 0;
 154
 155         ret = btrfs_insert_item(trans, root, &key, inode_item,
 156                                 sizeof(*inode_item));
 157         return ret;
 158 }
 159
 160 struct btrfs_inode_ref *btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
 161                 struct btrfs_root *root, struct btrfs_path *path,
 162                 const char *name, int namelen, u64 ino, u64 parent_ino,
 163                 int ins_len)
 164 {
 165         struct btrfs_key key;
 166         struct btrfs_inode_ref *ret_inode_ref = NULL;
 167         int ret = 0;
 168
 169         key.objectid = ino;
 170         key.type = BTRFS_INODE_REF_KEY;
 171         key.offset = parent_ino;
 172
 173         ret = btrfs_search_slot(trans, root, &key, path, ins_len,
 174                                 ins_len ? 1 : 0);
 175         if (ret)
 176                 goto out;
 177
 178         find_name_in_backref(path, name, namelen, &ret_inode_ref);
 179 out:
 180         if (ret < 0)
 181                 return ERR_PTR(ret);
 182         else
 183                 return ret_inode_ref;
 184 }
 185
 186 static int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
 187                 u64 parent_ino, const char *name, int namelen,
 188                 struct btrfs_inode_extref **extref_ret)
 189 {
 190         struct extent_buffer *node;
 191         struct btrfs_inode_extref *extref;
 192         unsigned long ptr;
 193         unsigned long name_ptr;
 194         u32 item_size;
 195         u32 cur_offset = 0;
 196         int ref_name_len;
 197         int slot;
 198
 199         node = path->nodes[0];
 200         slot = path->slots[0];
 201         item_size = btrfs_item_size_nr(node, slot);
 202         ptr = btrfs_item_ptr_offset(node, slot);
 203
 204         /*
 205          * Search all extended backrefs in this item. We're only looking
 206          * through any collisions so most of the time this is just going to
 207          * compare against one buffer. If all is well, we'll return success and
 208          * the inode ref object.
 209          */
 210         while (cur_offset < item_size) {
 211                 extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
 212                 name_ptr = (unsigned long)(&extref->name);
 213                 ref_name_len = btrfs_inode_extref_name_len(node, extref);
 214
 215                 if (ref_name_len == namelen &&
 216                     btrfs_inode_extref_parent(node, extref) == parent_ino &&
 217                     (memcmp_extent_buffer(node, name, name_ptr, namelen) == 0))
 218                 {
 219                         if (extref_ret)
 220                                 *extref_ret = extref;
 221                         return 1;
 222                 }
 223
 224                 cur_offset += ref_name_len + sizeof(*extref);
 225         }
 226
 227         return 0;
 228 }
 229
 230 struct btrfs_inode_extref *btrfs_lookup_inode_extref(struct btrfs_trans_handle
 231                 *trans, struct btrfs_path *path, struct btrfs_root *root,
 232                 u64 ino, u64 parent_ino, u64 index, const char *name,
 233                 int namelen, int ins_len)
 234 {
 235         struct btrfs_key key;
 236         struct btrfs_inode_extref *extref;
 237         int ret = 0;
 238
 239         key.objectid = ino;
 240         key.type = BTRFS_INODE_EXTREF_KEY;
 241         key.offset = btrfs_extref_hash(parent_ino, name, namelen);
 242
 243         ret = btrfs_search_slot(trans, root, &key, path, ins_len,
 244                         ins_len ? 1 : 0);
 245         if (ret < 0)
 246                 return ERR_PTR(ret);
 247         if (ret > 0)
 248                 return NULL;
 249         if (!btrfs_find_name_in_ext_backref(path, parent_ino, name,
 250                                             namelen, &extref))
 251                 return NULL;
 252
 253         return extref;
 254 }
 255
 256 int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 257                            struct btrfs_root *root,
 258                            const char *name, int name_len,
 259                            u64 inode_objectid, u64 ref_objectid,
 260                            u64 *index)
 261 {
 262         struct btrfs_path *path;
 263         struct btrfs_key key;
 264         struct btrfs_inode_extref *extref;
 265         struct extent_buffer *leaf;
 266         int ret;
 267         int del_len = name_len + sizeof(*extref);
 268         unsigned long ptr;
 269         unsigned long item_start;
 270         u32 item_size;
 271
 272         key.objectid = inode_objectid;
 273         key.type = BTRFS_INODE_EXTREF_KEY;
 274         key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
 275
 276         path = btrfs_alloc_path();
 277         if (!path)
 278                 return -ENOMEM;
 279
 280         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 281         if (ret > 0)
 282                 ret = -ENOENT;
 283         if (ret < 0)
 284                 goto out;
 285
 286         /*
 287          * Sanity check - did we find the right item for this name?  This
 288          * should always succeed so error here will make the FS readonly.
 289          */
 290         if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
 291                                             name, name_len, &extref)) {
 292                 ret = -ENOENT;
 293                 goto out;
 294         }
 295
 296         leaf = path->nodes[0];
 297         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 298         if (index)
 299                 *index = btrfs_inode_extref_index(leaf, extref);
 300
 301         if (del_len == item_size) {
 302                 /*
 303                  * Common case only one ref in the item, remove the whole item.
 304                  */
 305                 ret = btrfs_del_item(trans, root, path);
 306                 goto out;
 307         }
 308
 309         ptr = (unsigned long)extref;
 310         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 311
 312         memmove_extent_buffer(leaf, ptr, ptr + del_len,
 313                               item_size - (ptr + del_len - item_start));
 314
 315         btrfs_truncate_item(root, path, item_size - del_len, 1);
 316
 317 out:
 318         btrfs_free_path(path);
 319
 320         return ret;
 321 }
 322
 323 /*
 324  * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
 325  *
 326  * The caller must have checked against BTRFS_LINK_MAX already.
 327  */
 328 int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 329                               struct btrfs_root *root,
 330                               const char *name, int name_len,
 331                               u64 inode_objectid, u64 ref_objectid, u64 index)
 332 {
 333         struct btrfs_inode_extref *extref;
 334         int ret;
 335         int ins_len = name_len + sizeof(*extref);
 336         unsigned long ptr;
 337         struct btrfs_path *path;
 338         struct btrfs_key key;
 339         struct extent_buffer *leaf;
 340         struct btrfs_item *item;
 341
 342         key.objectid = inode_objectid;
 343         key.type = BTRFS_INODE_EXTREF_KEY;
 344         key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
 345
 346         path = btrfs_alloc_path();
 347         if (!path)
 348                 return -ENOMEM;
 349
 350         ret = btrfs_insert_empty_item(trans, root, path, &key,
 351                                       ins_len);
 352         if (ret == -EEXIST) {
 353                 if (btrfs_find_name_in_ext_backref(path, ref_objectid,
 354                                                    name, name_len, NULL))
 355                         goto out;
 356
 357                 btrfs_extend_item(root, path, ins_len);
 358                 ret = 0;
 359         }
 360
 361         if (ret < 0)
 362                 goto out;
 363
 364         leaf = path->nodes[0];
 365         item = btrfs_item_nr(path->slots[0]);
 366         ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
 367         ptr += btrfs_item_size(leaf, item) - ins_len;
 368         extref = (struct btrfs_inode_extref *)ptr;
 369
 370         btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
 371         btrfs_set_inode_extref_index(path->nodes[0], extref, index);
 372         btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
 373
 374         ptr = (unsigned long)&extref->name;
 375         write_extent_buffer(path->nodes[0], name, ptr, name_len);
 376         btrfs_mark_buffer_dirty(path->nodes[0]);
 377
 378 out:
 379         btrfs_free_path(path);
 380
 381         return ret;
 382 }
 383
 384 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 385                         struct btrfs_root *root, const char *name, int name_len,
 386                         u64 ino, u64 parent_ino, u64 *index)
 387 {
 388         struct btrfs_path *path;
 389         struct btrfs_key key;
 390         struct btrfs_inode_ref *ref;
 391         struct extent_buffer *leaf;
 392         unsigned long ptr;
 393         unsigned long item_start;
 394         u32 item_size;
 395         u32 sub_item_len;
 396         int ret;
 397         int search_ext_refs = 0;
 398         int del_len = name_len + sizeof(*ref);
 399
 400         key.objectid = ino;
 401         key.offset = parent_ino;
 402         key.type = BTRFS_INODE_REF_KEY;
 403
 404         path = btrfs_alloc_path();
 405         if (!path)
 406                 return -ENOMEM;
 407
 408         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 409         if (ret > 0) {
 410                 ret = -ENOENT;
 411                 search_ext_refs = 1;
 412                 goto out;
 413         } else if (ret < 0) {
 414                 goto out;
 415         }
 416         if (!find_name_in_backref(path, name, name_len, &ref)) {
 417                 ret = -ENOENT;
 418                 search_ext_refs = 1;
 419                 goto out;
 420         }
 421         leaf = path->nodes[0];
 422         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 423
 424         if (index)
 425                 *index = btrfs_inode_ref_index(leaf, ref);
 426
 427         if (del_len == item_size) {
 428                 ret = btrfs_del_item(trans, root, path);
 429                 goto out;
 430         }
 431         ptr = (unsigned long)ref;
 432         sub_item_len = name_len + sizeof(*ref);
 433         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 434         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 435                               item_size - (ptr + sub_item_len - item_start));
 436         btrfs_truncate_item(root, path, item_size - sub_item_len, 1);
 437         btrfs_mark_buffer_dirty(path->nodes[0]);
 438 out:
 439         btrfs_free_path(path);
 440
 441         if (search_ext_refs &&
 442             btrfs_fs_incompat(root->fs_info, EXTENDED_IREF)) {
 443                 /*
 444                  * No refs were found, or we could not find the name in our ref
 445                  * array. Find and remove the extended inode ref then.
 446                  */
 447                 return btrfs_del_inode_extref(trans, root, name, name_len,
 448                                               ino, parent_ino, index);
 449         }
 450
 451         return ret;
 452 }