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