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