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_create_file(struct btrfs_trans_handle *trans,
  33                       struct btrfs_root *root, u64 dirid, u64 *objectid)
  34 {
  35         return 0;
  36 }
  37
  38 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  39                              struct btrfs_root *root,
  40                              u64 objectid, u64 pos, u64 offset,
  41                              u64 disk_num_bytes, u64 num_bytes)
  42 {
  43         int ret = 0;
  44         struct btrfs_file_extent_item *item;
  45         struct btrfs_key file_key;
  46         struct btrfs_path *path;
  47         struct extent_buffer *leaf;
  48
  49         path = btrfs_alloc_path();
  50         BUG_ON(!path);
  51         file_key.objectid = objectid;
  52         file_key.offset = pos;
  53         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  54
  55         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  56                                       sizeof(*item));
  57         if (ret < 0)
  58                 goto out;
  59         BUG_ON(ret);
  60         leaf = path->nodes[0];
  61         item = btrfs_item_ptr(leaf, path->slots[0],
  62                               struct btrfs_file_extent_item);
  63         btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
  64         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  65         btrfs_set_file_extent_offset(leaf, item, 0);
  66         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  67         btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
  68         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  69         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  70         btrfs_set_file_extent_compression(leaf, item, 0);
  71         btrfs_set_file_extent_encryption(leaf, item, 0);
  72         btrfs_set_file_extent_other_encoding(leaf, item, 0);
  73         btrfs_mark_buffer_dirty(leaf);
  74 out:
  75         btrfs_free_path(path);
  76         return ret;
  77 }
  78
  79 int btrfs_insert_inline_extent(struct btrfs_trans_handle *trans,
  80                                struct btrfs_root *root, u64 objectid,
  81                                u64 offset, char *buffer, size_t size)
  82 {
  83         struct btrfs_key key;
  84         struct btrfs_path *path;
  85         struct extent_buffer *leaf;
  86         unsigned long ptr;
  87         struct btrfs_file_extent_item *ei;
  88         u32 datasize;
  89         int err = 0;
  90         int ret;
  91
  92         path = btrfs_alloc_path();
  93         if (!path)
  94                 return -ENOMEM;
  95
  96         key.objectid = objectid;
  97         key.offset = offset;
  98         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
  99
 100         datasize = btrfs_file_extent_calc_inline_size(size);
 101         ret = btrfs_insert_empty_item(trans, root, path, &key, datasize);
 102         if (ret) {
 103                 err = ret;
 104                 goto fail;
 105         }
 106
 107         leaf = path->nodes[0];
 108         ei = btrfs_item_ptr(leaf, path->slots[0],
 109                             struct btrfs_file_extent_item);
 110         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 111         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 112         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 113         btrfs_set_file_extent_compression(leaf, ei, 0);
 114         btrfs_set_file_extent_encryption(leaf, ei, 0);
 115         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 116
 117         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 118         write_extent_buffer(leaf, buffer, ptr, size);
 119         btrfs_mark_buffer_dirty(leaf);
 120 fail:
 121         btrfs_free_path(path);
 122         return err;
 123 }
 124
 125 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 126                                           struct btrfs_root *root,
 127                                           struct btrfs_path *path,
 128                                           u64 bytenr, int cow)
 129 {
 130         int ret;
 131         struct btrfs_key file_key;
 132         struct btrfs_key found_key;
 133         struct btrfs_csum_item *item;
 134         struct extent_buffer *leaf;
 135         u64 csum_offset = 0;
 136         u16 csum_size =
 137                 btrfs_super_csum_size(&root->fs_info->super_copy);
 138         int csums_in_item;
 139
 140         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 141         file_key.offset = bytenr;
 142         btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY);
 143         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 144         if (ret < 0)
 145                 goto fail;
 146         leaf = path->nodes[0];
 147         if (ret > 0) {
 148                 ret = 1;
 149                 if (path->slots[0] == 0)
 150                         goto fail;
 151                 path->slots[0]--;
 152                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 153                 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY)
 154                         goto fail;
 155
 156                 csum_offset = (bytenr - found_key.offset) / root->sectorsize;
 157                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 158                 csums_in_item /= csum_size;
 159
 160                 if (csum_offset >= csums_in_item) {
 161                         ret = -EFBIG;
 162                         goto fail;
 163                 }
 164         }
 165         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 166         item = (struct btrfs_csum_item *)((unsigned char *)item +
 167                                           csum_offset * csum_size);
 168         return item;
 169 fail:
 170         if (ret > 0)
 171                 ret = -ENOENT;
 172         return ERR_PTR(ret);
 173 }
 174
 175 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 176                              struct btrfs_root *root,
 177                              struct btrfs_path *path, u64 objectid,
 178                              u64 offset, int mod)
 179 {
 180         int ret;
 181         struct btrfs_key file_key;
 182         int ins_len = mod < 0 ? -1 : 0;
 183         int cow = mod != 0;
 184
 185         file_key.objectid = objectid;
 186         file_key.offset = offset;
 187         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 188         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 189         return ret;
 190 }
 191
 192 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 193                           struct btrfs_root *root, u64 alloc_end,
 194                           u64 bytenr, char *data, size_t len)
 195 {
 196         int ret;
 197         struct btrfs_key file_key;
 198         struct btrfs_key found_key;
 199         u64 next_offset = (u64)-1;
 200         int found_next = 0;
 201         struct btrfs_path *path;
 202         struct btrfs_csum_item *item;
 203         struct extent_buffer *leaf = NULL;
 204         u64 csum_offset;
 205         u32 csum_result = ~(u32)0;
 206         u32 nritems;
 207         u32 ins_size;
 208         u16 csum_size =
 209                 btrfs_super_csum_size(&root->fs_info->super_copy);
 210
 211         path = btrfs_alloc_path();
 212         BUG_ON(!path);
 213
 214         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 215         file_key.offset = bytenr;
 216         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 217
 218         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 219         if (!IS_ERR(item)) {
 220                 leaf = path->nodes[0];
 221                 goto found;
 222         }
 223         ret = PTR_ERR(item);
 224         if (ret == -EFBIG) {
 225                 u32 item_size;
 226                 /* we found one, but it isn't big enough yet */
 227                 leaf = path->nodes[0];
 228                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 229                 if ((item_size / csum_size) >= MAX_CSUM_ITEMS(root, csum_size)) {
 230                         /* already at max size, make a new one */
 231                         goto insert;
 232                 }
 233         } else {
 234                 int slot = path->slots[0] + 1;
 235                 /* we didn't find a csum item, insert one */
 236                 nritems = btrfs_header_nritems(path->nodes[0]);
 237                 if (path->slots[0] >= nritems - 1) {
 238                         ret = btrfs_next_leaf(root, path);
 239                         if (ret == 1)
 240                                 found_next = 1;
 241                         if (ret != 0)
 242                                 goto insert;
 243                         slot = 0;
 244                 }
 245                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 246                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 247                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 248                         found_next = 1;
 249                         goto insert;
 250                 }
 251                 next_offset = found_key.offset;
 252                 found_next = 1;
 253                 goto insert;
 254         }
 255
 256         /*
 257          * at this point, we know the tree has an item, but it isn't big
 258          * enough yet to put our csum in.  Grow it
 259          */
 260         btrfs_release_path(root, path);
 261         ret = btrfs_search_slot(trans, root, &file_key, path,
 262                                 csum_size, 1);
 263         if (ret < 0)
 264                 goto fail;
 265         if (ret == 0) {
 266                 BUG();
 267         }
 268         if (path->slots[0] == 0) {
 269                 goto insert;
 270         }
 271         path->slots[0]--;
 272         leaf = path->nodes[0];
 273         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 274         csum_offset = (file_key.offset - found_key.offset) / root->sectorsize;
 275         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 276             found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 277             csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
 278                 goto insert;
 279         }
 280         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 281             csum_size) {
 282                 u32 diff = (csum_offset + 1) * csum_size;
 283                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 284                 if (diff != csum_size)
 285                         goto insert;
 286                 ret = btrfs_extend_item(trans, root, path, diff);
 287                 BUG_ON(ret);
 288                 goto csum;
 289         }
 290
 291 insert:
 292         btrfs_release_path(root, path);
 293         csum_offset = 0;
 294         if (found_next) {
 295                 u64 tmp = min(alloc_end, next_offset);
 296                 tmp -= file_key.offset;
 297                 tmp /= root->sectorsize;
 298                 tmp = max((u64)1, tmp);
 299                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
 300                 ins_size = csum_size * tmp;
 301         } else {
 302                 ins_size = csum_size;
 303         }
 304         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 305                                       ins_size);
 306         if (ret < 0)
 307                 goto fail;
 308         if (ret != 0) {
 309                 WARN_ON(1);
 310                 goto fail;
 311         }
 312 csum:
 313         leaf = path->nodes[0];
 314         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 315         ret = 0;
 316         item = (struct btrfs_csum_item *)((unsigned char *)item +
 317                                           csum_offset * csum_size);
 318 found:
 319         csum_result = btrfs_csum_data(root, data, csum_result, len);
 320         btrfs_csum_final(csum_result, (char *)&csum_result);
 321         if (csum_result == 0) {
 322                 printk("csum result is 0 for block %llu\n",
 323                        (unsigned long long)bytenr);
 324         }
 325
 326         write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 327                             csum_size);
 328         btrfs_mark_buffer_dirty(path->nodes[0]);
 329 fail:
 330         btrfs_release_path(root, path);
 331         btrfs_free_path(path);
 332         return ret;
 333 }
 334
 335 /*
 336  * helper function for csum removal, this expects the
 337  * key to describe the csum pointed to by the path, and it expects
 338  * the csum to overlap the range [bytenr, len]
 339  *
 340  * The csum should not be entirely contained in the range and the
 341  * range should not be entirely contained in the csum.
 342  *
 343  * This calls btrfs_truncate_item with the correct args based on the
 344  * overlap, and fixes up the key as required.
 345  */
 346 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
 347                                       struct btrfs_root *root,
 348                                       struct btrfs_path *path,
 349                                       struct btrfs_key *key,
 350                                       u64 bytenr, u64 len)
 351 {
 352         struct extent_buffer *leaf;
 353         u16 csum_size =
 354                 btrfs_super_csum_size(&root->fs_info->super_copy);
 355         u64 csum_end;
 356         u64 end_byte = bytenr + len;
 357         u32 blocksize = root->sectorsize;
 358         int ret;
 359
 360         leaf = path->nodes[0];
 361         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 362         csum_end *= root->sectorsize;
 363         csum_end += key->offset;
 364
 365         if (key->offset < bytenr && csum_end <= end_byte) {
 366                 /*
 367                  *         [ bytenr - len ]
 368                  *         [   ]
 369                  *   [csum     ]
 370                  *   A simple truncate off the end of the item
 371                  */
 372                 u32 new_size = (bytenr - key->offset) / blocksize;
 373                 new_size *= csum_size;
 374                 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
 375                 BUG_ON(ret);
 376         } else if (key->offset >= bytenr && csum_end > end_byte &&
 377                    end_byte > key->offset) {
 378                 /*
 379                  *         [ bytenr - len ]
 380                  *                 [ ]
 381                  *                 [csum     ]
 382                  * we need to truncate from the beginning of the csum
 383                  */
 384                 u32 new_size = (csum_end - end_byte) / blocksize;
 385                 new_size *= csum_size;
 386
 387                 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
 388                 BUG_ON(ret);
 389
 390                 key->offset = end_byte;
 391                 ret = btrfs_set_item_key_safe(trans, root, path, key);
 392                 BUG_ON(ret);
 393         } else {
 394                 BUG();
 395         }
 396         return 0;
 397 }
 398
 399 /*
 400  * deletes the csum items from the csum tree for a given
 401  * range of bytes.
 402  */
 403 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 404                     struct btrfs_root *root, u64 bytenr, u64 len)
 405 {
 406         struct btrfs_path *path;
 407         struct btrfs_key key;
 408         u64 end_byte = bytenr + len;
 409         u64 csum_end;
 410         struct extent_buffer *leaf;
 411         int ret;
 412         u16 csum_size =
 413                 btrfs_super_csum_size(&root->fs_info->super_copy);
 414         int blocksize = root->sectorsize;
 415
 416         root = root->fs_info->csum_root;
 417
 418         path = btrfs_alloc_path();
 419
 420         while (1) {
 421                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 422                 key.offset = end_byte - 1;
 423                 key.type = BTRFS_EXTENT_CSUM_KEY;
 424
 425                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 426                 if (ret > 0) {
 427                         if (path->slots[0] == 0)
 428                                 goto out;
 429                         path->slots[0]--;
 430                 }
 431                 leaf = path->nodes[0];
 432                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 433
 434                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 435                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 436                         break;
 437                 }
 438
 439                 if (key.offset >= end_byte)
 440                         break;
 441
 442                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 443                 csum_end *= blocksize;
 444                 csum_end += key.offset;
 445
 446                 /* this csum ends before we start, we're done */
 447                 if (csum_end <= bytenr)
 448                         break;
 449
 450                 /* delete the entire item, it is inside our range */
 451                 if (key.offset >= bytenr && csum_end <= end_byte) {
 452                         ret = btrfs_del_item(trans, root, path);
 453                         BUG_ON(ret);
 454                 } else if (key.offset < bytenr && csum_end > end_byte) {
 455                         unsigned long offset;
 456                         unsigned long shift_len;
 457                         unsigned long item_offset;
 458                         /*
 459                          *        [ bytenr - len ]
 460                          *     [csum                ]
 461                          *
 462                          * Our bytes are in the middle of the csum,
 463                          * we need to split this item and insert a new one.
 464                          *
 465                          * But we can't drop the path because the
 466                          * csum could change, get removed, extended etc.
 467                          *
 468                          * The trick here is the max size of a csum item leaves
 469                          * enough room in the tree block for a single
 470                          * item header.  So, we split the item in place,
 471                          * adding a new header pointing to the existing
 472                          * bytes.  Then we loop around again and we have
 473                          * a nicely formed csum item that we can neatly
 474                          * truncate.
 475                          */
 476                         offset = (bytenr - key.offset) / blocksize;
 477                         offset *= csum_size;
 478
 479                         shift_len = (len / blocksize) * csum_size;
 480
 481                         item_offset = btrfs_item_ptr_offset(leaf,
 482                                                             path->slots[0]);
 483
 484                         memset_extent_buffer(leaf, 0, item_offset + offset,
 485                                              shift_len);
 486                         key.offset = bytenr;
 487
 488                         /*
 489                          * btrfs_split_item returns -EAGAIN when the
 490                          * item changed size or key
 491                          */
 492                         ret = btrfs_split_item(trans, root, path, &key, offset);
 493                         BUG_ON(ret && ret != -EAGAIN);
 494
 495                         key.offset = end_byte - 1;
 496                 } else {
 497                         ret = truncate_one_csum(trans, root, path,
 498                                                 &key, bytenr, len);
 499                         BUG_ON(ret);
 500                 }
 501                 btrfs_release_path(root, path);
 502         }
 503 out:
 504         btrfs_free_path(path);
 505         return 0;
 506 }