file-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 <stdio.h>
  20 #include <stdlib.h>
  21 #include "kerncompat.h"
  22 #include "radix-tree.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "transaction.h"
  26 #include "print-tree.h"
  27 #include "crc32c.h"
  28 #include "internal.h"
  29
  30 #define MAX_CSUM_ITEMS(r,size) ((((BTRFS_LEAF_DATA_SIZE(r) - \
  31                                sizeof(struct btrfs_item) * 2) / \
  32                                size) - 1))
  33 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  34                              struct btrfs_root *root,
  35                              u64 objectid, u64 pos, u64 offset,
  36                              u64 disk_num_bytes, u64 num_bytes)
  37 {
  38         int ret = 0;
  39         struct btrfs_file_extent_item *item;
  40         struct btrfs_key file_key;
  41         struct btrfs_path *path;
  42         struct extent_buffer *leaf;
  43
  44         path = btrfs_alloc_path();
  45         if (!path)
  46                 return -ENOMEM;
  47
  48         file_key.objectid = objectid;
  49         file_key.offset = pos;
  50         file_key.type = BTRFS_EXTENT_DATA_KEY;
  51
  52         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  53                                       sizeof(*item));
  54         if (ret < 0)
  55                 goto out;
  56         BUG_ON(ret);
  57         leaf = path->nodes[0];
  58         item = btrfs_item_ptr(leaf, path->slots[0],
  59                               struct btrfs_file_extent_item);
  60         btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
  61         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  62         btrfs_set_file_extent_offset(leaf, item, 0);
  63         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  64         btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
  65         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  66         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  67         btrfs_set_file_extent_compression(leaf, item, 0);
  68         btrfs_set_file_extent_encryption(leaf, item, 0);
  69         btrfs_set_file_extent_other_encoding(leaf, item, 0);
  70         btrfs_mark_buffer_dirty(leaf);
  71 out:
  72         btrfs_free_path(path);
  73         return ret;
  74 }
  75
  76 int btrfs_insert_inline_extent(struct btrfs_trans_handle *trans,
  77                                struct btrfs_root *root, u64 objectid,
  78                                u64 offset, char *buffer, size_t size)
  79 {
  80         struct btrfs_key key;
  81         struct btrfs_path *path;
  82         struct extent_buffer *leaf;
  83         unsigned long ptr;
  84         struct btrfs_file_extent_item *ei;
  85         u32 datasize;
  86         int err = 0;
  87         int ret;
  88
  89         path = btrfs_alloc_path();
  90         if (!path)
  91                 return -ENOMEM;
  92
  93         key.objectid = objectid;
  94         key.offset = offset;
  95         key.type = BTRFS_EXTENT_DATA_KEY;
  96
  97         datasize = btrfs_file_extent_calc_inline_size(size);
  98         ret = btrfs_insert_empty_item(trans, root, path, &key, datasize);
  99         if (ret) {
 100                 err = ret;
 101                 goto fail;
 102         }
 103
 104         leaf = path->nodes[0];
 105         ei = btrfs_item_ptr(leaf, path->slots[0],
 106                             struct btrfs_file_extent_item);
 107         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 108         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 109         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 110         btrfs_set_file_extent_compression(leaf, ei, 0);
 111         btrfs_set_file_extent_encryption(leaf, ei, 0);
 112         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 113
 114         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 115         write_extent_buffer(leaf, buffer, ptr, size);
 116         btrfs_mark_buffer_dirty(leaf);
 117 fail:
 118         btrfs_free_path(path);
 119         return err;
 120 }
 121
 122 static struct btrfs_csum_item *
 123 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 124                   struct btrfs_root *root,
 125                   struct btrfs_path *path,
 126                   u64 bytenr, int cow)
 127 {
 128         int ret;
 129         struct btrfs_key file_key;
 130         struct btrfs_key found_key;
 131         struct btrfs_csum_item *item;
 132         struct extent_buffer *leaf;
 133         u64 csum_offset = 0;
 134         u16 csum_size =
 135                 btrfs_super_csum_size(root->fs_info->super_copy);
 136         int csums_in_item;
 137
 138         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 139         file_key.offset = bytenr;
 140         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 141         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 142         if (ret < 0)
 143                 goto fail;
 144         leaf = path->nodes[0];
 145         if (ret > 0) {
 146                 ret = 1;
 147                 if (path->slots[0] == 0)
 148                         goto fail;
 149                 path->slots[0]--;
 150                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 151                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 152                         goto fail;
 153
 154                 csum_offset = (bytenr - found_key.offset) / root->sectorsize;
 155                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 156                 csums_in_item /= csum_size;
 157
 158                 if (csum_offset >= csums_in_item) {
 159                         ret = -EFBIG;
 160                         goto fail;
 161                 }
 162         }
 163         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 164         item = (struct btrfs_csum_item *)((unsigned char *)item +
 165                                           csum_offset * csum_size);
 166         return item;
 167 fail:
 168         if (ret > 0)
 169                 ret = -ENOENT;
 170         return ERR_PTR(ret);
 171 }
 172
 173 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 174                           struct btrfs_root *root, u64 alloc_end,
 175                           u64 bytenr, char *data, size_t len)
 176 {
 177         int ret = 0;
 178         struct btrfs_key file_key;
 179         struct btrfs_key found_key;
 180         u64 next_offset = (u64)-1;
 181         int found_next = 0;
 182         struct btrfs_path *path;
 183         struct btrfs_csum_item *item;
 184         struct extent_buffer *leaf = NULL;
 185         u64 csum_offset;
 186         u32 csum_result = ~(u32)0;
 187         u32 nritems;
 188         u32 ins_size;
 189         u16 csum_size =
 190                 btrfs_super_csum_size(root->fs_info->super_copy);
 191
 192         path = btrfs_alloc_path();
 193         if (!path)
 194                 return -ENOMEM;
 195
 196         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 197         file_key.offset = bytenr;
 198         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 199
 200         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 201         if (!IS_ERR(item)) {
 202                 leaf = path->nodes[0];
 203                 ret = 0;
 204                 goto found;
 205         }
 206         ret = PTR_ERR(item);
 207         if (ret == -EFBIG) {
 208                 u32 item_size;
 209                 /* we found one, but it isn't big enough yet */
 210                 leaf = path->nodes[0];
 211                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 212                 if ((item_size / csum_size) >= MAX_CSUM_ITEMS(root, csum_size)) {
 213                         /* already at max size, make a new one */
 214                         goto insert;
 215                 }
 216         } else {
 217                 int slot = path->slots[0] + 1;
 218                 /* we didn't find a csum item, insert one */
 219                 nritems = btrfs_header_nritems(path->nodes[0]);
 220                 if (path->slots[0] >= nritems - 1) {
 221                         ret = btrfs_next_leaf(root, path);
 222                         if (ret == 1)
 223                                 found_next = 1;
 224                         if (ret != 0)
 225                                 goto insert;
 226                         slot = 0;
 227                 }
 228                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 229                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 230                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 231                         found_next = 1;
 232                         goto insert;
 233                 }
 234                 next_offset = found_key.offset;
 235                 found_next = 1;
 236                 goto insert;
 237         }
 238
 239         /*
 240          * at this point, we know the tree has an item, but it isn't big
 241          * enough yet to put our csum in.  Grow it
 242          */
 243         btrfs_release_path(path);
 244         ret = btrfs_search_slot(trans, root, &file_key, path,
 245                                 csum_size, 1);
 246         if (ret < 0)
 247                 goto fail;
 248         if (ret == 0) {
 249                 BUG();
 250         }
 251         if (path->slots[0] == 0) {
 252                 goto insert;
 253         }
 254         path->slots[0]--;
 255         leaf = path->nodes[0];
 256         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 257         csum_offset = (file_key.offset - found_key.offset) / root->sectorsize;
 258         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 259             found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 260             csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
 261                 goto insert;
 262         }
 263         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 264             csum_size) {
 265                 u32 diff = (csum_offset + 1) * csum_size;
 266                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 267                 if (diff != csum_size)
 268                         goto insert;
 269                 ret = btrfs_extend_item(trans, root, path, diff);
 270                 BUG_ON(ret);
 271                 goto csum;
 272         }
 273
 274 insert:
 275         btrfs_release_path(path);
 276         csum_offset = 0;
 277         if (found_next) {
 278                 u64 tmp = min(alloc_end, next_offset);
 279                 tmp -= file_key.offset;
 280                 tmp /= root->sectorsize;
 281                 tmp = max((u64)1, tmp);
 282                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
 283                 ins_size = csum_size * tmp;
 284         } else {
 285                 ins_size = csum_size;
 286         }
 287         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 288                                       ins_size);
 289         if (ret < 0)
 290                 goto fail;
 291         if (ret != 0) {
 292                 WARN_ON(1);
 293                 goto fail;
 294         }
 295 csum:
 296         leaf = path->nodes[0];
 297         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 298         ret = 0;
 299         item = (struct btrfs_csum_item *)((unsigned char *)item +
 300                                           csum_offset * csum_size);
 301 found:
 302         csum_result = btrfs_csum_data(root, data, csum_result, len);
 303         btrfs_csum_final(csum_result, (u8 *)&csum_result);
 304         if (csum_result == 0) {
 305                 printk("csum result is 0 for block %llu\n",
 306                        (unsigned long long)bytenr);
 307         }
 308
 309         write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 310                             csum_size);
 311         btrfs_mark_buffer_dirty(path->nodes[0]);
 312 fail:
 313         btrfs_free_path(path);
 314         return ret;
 315 }
 316
 317 /*
 318  * helper function for csum removal, this expects the
 319  * key to describe the csum pointed to by the path, and it expects
 320  * the csum to overlap the range [bytenr, len]
 321  *
 322  * The csum should not be entirely contained in the range and the
 323  * range should not be entirely contained in the csum.
 324  *
 325  * This calls btrfs_truncate_item with the correct args based on the
 326  * overlap, and fixes up the key as required.
 327  */
 328 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
 329                                       struct btrfs_root *root,
 330                                       struct btrfs_path *path,
 331                                       struct btrfs_key *key,
 332                                       u64 bytenr, u64 len)
 333 {
 334         struct extent_buffer *leaf;
 335         u16 csum_size =
 336                 btrfs_super_csum_size(root->fs_info->super_copy);
 337         u64 csum_end;
 338         u64 end_byte = bytenr + len;
 339         u32 blocksize = root->sectorsize;
 340         int ret;
 341
 342         leaf = path->nodes[0];
 343         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 344         csum_end *= root->sectorsize;
 345         csum_end += key->offset;
 346
 347         if (key->offset < bytenr && csum_end <= end_byte) {
 348                 /*
 349                  *         [ bytenr - len ]
 350                  *         [   ]
 351                  *   [csum     ]
 352                  *   A simple truncate off the end of the item
 353                  */
 354                 u32 new_size = (bytenr - key->offset) / blocksize;
 355                 new_size *= csum_size;
 356                 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
 357                 BUG_ON(ret);
 358         } else if (key->offset >= bytenr && csum_end > end_byte &&
 359                    end_byte > key->offset) {
 360                 /*
 361                  *         [ bytenr - len ]
 362                  *                 [ ]
 363                  *                 [csum     ]
 364                  * we need to truncate from the beginning of the csum
 365                  */
 366                 u32 new_size = (csum_end - end_byte) / blocksize;
 367                 new_size *= csum_size;
 368
 369                 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
 370                 BUG_ON(ret);
 371
 372                 key->offset = end_byte;
 373                 ret = btrfs_set_item_key_safe(root, path, key);
 374                 BUG_ON(ret);
 375         } else {
 376                 BUG();
 377         }
 378         return 0;
 379 }
 380
 381 /*
 382  * deletes the csum items from the csum tree for a given
 383  * range of bytes.
 384  */
 385 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 386                     struct btrfs_root *root, u64 bytenr, u64 len)
 387 {
 388         struct btrfs_path *path;
 389         struct btrfs_key key;
 390         u64 end_byte = bytenr + len;
 391         u64 csum_end;
 392         struct extent_buffer *leaf;
 393         int ret;
 394         u16 csum_size =
 395                 btrfs_super_csum_size(root->fs_info->super_copy);
 396         int blocksize = root->sectorsize;
 397
 398         root = root->fs_info->csum_root;
 399
 400         path = btrfs_alloc_path();
 401         if (!path)
 402                 return -ENOMEM;
 403
 404         while (1) {
 405                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 406                 key.offset = end_byte - 1;
 407                 key.type = BTRFS_EXTENT_CSUM_KEY;
 408
 409                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 410                 if (ret > 0) {
 411                         if (path->slots[0] == 0)
 412                                 goto out;
 413                         path->slots[0]--;
 414                 }
 415                 leaf = path->nodes[0];
 416                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 417
 418                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 419                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 420                         break;
 421                 }
 422
 423                 if (key.offset >= end_byte)
 424                         break;
 425
 426                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 427                 csum_end *= blocksize;
 428                 csum_end += key.offset;
 429
 430                 /* this csum ends before we start, we're done */
 431                 if (csum_end <= bytenr)
 432                         break;
 433
 434                 /* delete the entire item, it is inside our range */
 435                 if (key.offset >= bytenr && csum_end <= end_byte) {
 436                         ret = btrfs_del_item(trans, root, path);
 437                         BUG_ON(ret);
 438                 } else if (key.offset < bytenr && csum_end > end_byte) {
 439                         unsigned long offset;
 440                         unsigned long shift_len;
 441                         unsigned long item_offset;
 442                         /*
 443                          *        [ bytenr - len ]
 444                          *     [csum                ]
 445                          *
 446                          * Our bytes are in the middle of the csum,
 447                          * we need to split this item and insert a new one.
 448                          *
 449                          * But we can't drop the path because the
 450                          * csum could change, get removed, extended etc.
 451                          *
 452                          * The trick here is the max size of a csum item leaves
 453                          * enough room in the tree block for a single
 454                          * item header.  So, we split the item in place,
 455                          * adding a new header pointing to the existing
 456                          * bytes.  Then we loop around again and we have
 457                          * a nicely formed csum item that we can neatly
 458                          * truncate.
 459                          */
 460                         offset = (bytenr - key.offset) / blocksize;
 461                         offset *= csum_size;
 462
 463                         shift_len = (len / blocksize) * csum_size;
 464
 465                         item_offset = btrfs_item_ptr_offset(leaf,
 466                                                             path->slots[0]);
 467
 468                         memset_extent_buffer(leaf, 0, item_offset + offset,
 469                                              shift_len);
 470                         key.offset = bytenr;
 471
 472                         /*
 473                          * btrfs_split_item returns -EAGAIN when the
 474                          * item changed size or key
 475                          */
 476                         ret = btrfs_split_item(trans, root, path, &key, offset);
 477                         BUG_ON(ret && ret != -EAGAIN);
 478
 479                         key.offset = end_byte - 1;
 480                 } else {
 481                         ret = truncate_one_csum(trans, root, path,
 482                                                 &key, bytenr, len);
 483                         BUG_ON(ret);
 484                 }
 485                 btrfs_release_path(path);
 486         }
 487 out:
 488         btrfs_free_path(path);
 489         return 0;
 490 }