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         int is_hole = 0;
  40         struct btrfs_file_extent_item *item;
  41         struct btrfs_key file_key;
  42         struct btrfs_path *path;
  43         struct extent_buffer *leaf;
  44
  45         if (offset == 0)
  46                 is_hole = 1;
  47         /* For NO_HOLES, we don't insert hole file extent */
  48         if (btrfs_fs_incompat(root->fs_info, NO_HOLES) && is_hole)
  49                 return 0;
  50
  51         /* For hole, its disk_bytenr and disk_num_bytes must be 0 */
  52         if (is_hole)
  53                 disk_num_bytes = 0;
  54
  55         path = btrfs_alloc_path();
  56         if (!path)
  57                 return -ENOMEM;
  58
  59         file_key.objectid = objectid;
  60         file_key.offset = pos;
  61         file_key.type = BTRFS_EXTENT_DATA_KEY;
  62
  63         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  64                                       sizeof(*item));
  65         if (ret < 0)
  66                 goto out;
  67         BUG_ON(ret);
  68         leaf = path->nodes[0];
  69         item = btrfs_item_ptr(leaf, path->slots[0],
  70                               struct btrfs_file_extent_item);
  71         btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
  72         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  73         btrfs_set_file_extent_offset(leaf, item, 0);
  74         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  75         btrfs_set_file_extent_ram_bytes(leaf, item, num_bytes);
  76         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  77         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  78         btrfs_set_file_extent_compression(leaf, item, 0);
  79         btrfs_set_file_extent_encryption(leaf, item, 0);
  80         btrfs_set_file_extent_other_encoding(leaf, item, 0);
  81         btrfs_mark_buffer_dirty(leaf);
  82 out:
  83         btrfs_free_path(path);
  84         return ret;
  85 }
  86
  87 int btrfs_insert_inline_extent(struct btrfs_trans_handle *trans,
  88                                struct btrfs_root *root, u64 objectid,
  89                                u64 offset, char *buffer, size_t size)
  90 {
  91         struct btrfs_key key;
  92         struct btrfs_path *path;
  93         struct extent_buffer *leaf;
  94         unsigned long ptr;
  95         struct btrfs_file_extent_item *ei;
  96         u32 datasize;
  97         int err = 0;
  98         int ret;
  99
 100         path = btrfs_alloc_path();
 101         if (!path)
 102                 return -ENOMEM;
 103
 104         key.objectid = objectid;
 105         key.offset = offset;
 106         key.type = BTRFS_EXTENT_DATA_KEY;
 107
 108         datasize = btrfs_file_extent_calc_inline_size(size);
 109         ret = btrfs_insert_empty_item(trans, root, path, &key, datasize);
 110         if (ret) {
 111                 err = ret;
 112                 goto fail;
 113         }
 114
 115         leaf = path->nodes[0];
 116         ei = btrfs_item_ptr(leaf, path->slots[0],
 117                             struct btrfs_file_extent_item);
 118         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 119         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 120         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 121         btrfs_set_file_extent_compression(leaf, ei, 0);
 122         btrfs_set_file_extent_encryption(leaf, ei, 0);
 123         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 124
 125         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 126         write_extent_buffer(leaf, buffer, ptr, size);
 127         btrfs_mark_buffer_dirty(leaf);
 128 fail:
 129         btrfs_free_path(path);
 130         return err;
 131 }
 132
 133 static struct btrfs_csum_item *
 134 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 135                   struct btrfs_root *root,
 136                   struct btrfs_path *path,
 137                   u64 bytenr, int cow)
 138 {
 139         int ret;
 140         struct btrfs_key file_key;
 141         struct btrfs_key found_key;
 142         struct btrfs_csum_item *item;
 143         struct extent_buffer *leaf;
 144         u64 csum_offset = 0;
 145         u16 csum_size =
 146                 btrfs_super_csum_size(root->fs_info->super_copy);
 147         int csums_in_item;
 148
 149         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 150         file_key.offset = bytenr;
 151         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 152         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 153         if (ret < 0)
 154                 goto fail;
 155         leaf = path->nodes[0];
 156         if (ret > 0) {
 157                 ret = 1;
 158                 if (path->slots[0] == 0)
 159                         goto fail;
 160                 path->slots[0]--;
 161                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 162                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 163                         goto fail;
 164
 165                 csum_offset = (bytenr - found_key.offset) / root->sectorsize;
 166                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 167                 csums_in_item /= csum_size;
 168
 169                 if (csum_offset >= csums_in_item) {
 170                         ret = -EFBIG;
 171                         goto fail;
 172                 }
 173         }
 174         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 175         item = (struct btrfs_csum_item *)((unsigned char *)item +
 176                                           csum_offset * csum_size);
 177         return item;
 178 fail:
 179         if (ret > 0)
 180                 ret = -ENOENT;
 181         return ERR_PTR(ret);
 182 }
 183
 184 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 185                           struct btrfs_root *root, u64 alloc_end,
 186                           u64 bytenr, char *data, size_t len)
 187 {
 188         int ret = 0;
 189         struct btrfs_key file_key;
 190         struct btrfs_key found_key;
 191         u64 next_offset = (u64)-1;
 192         int found_next = 0;
 193         struct btrfs_path *path;
 194         struct btrfs_csum_item *item;
 195         struct extent_buffer *leaf = NULL;
 196         u64 csum_offset;
 197         u32 csum_result = ~(u32)0;
 198         u32 nritems;
 199         u32 ins_size;
 200         u16 csum_size =
 201                 btrfs_super_csum_size(root->fs_info->super_copy);
 202
 203         path = btrfs_alloc_path();
 204         if (!path)
 205                 return -ENOMEM;
 206
 207         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 208         file_key.offset = bytenr;
 209         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 210
 211         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 212         if (!IS_ERR(item)) {
 213                 leaf = path->nodes[0];
 214                 ret = 0;
 215                 goto found;
 216         }
 217         ret = PTR_ERR(item);
 218         if (ret == -EFBIG) {
 219                 u32 item_size;
 220                 /* we found one, but it isn't big enough yet */
 221                 leaf = path->nodes[0];
 222                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 223                 if ((item_size / csum_size) >= MAX_CSUM_ITEMS(root, csum_size)) {
 224                         /* already at max size, make a new one */
 225                         goto insert;
 226                 }
 227         } else {
 228                 int slot = path->slots[0] + 1;
 229                 /* we didn't find a csum item, insert one */
 230                 nritems = btrfs_header_nritems(path->nodes[0]);
 231                 if (path->slots[0] >= nritems - 1) {
 232                         ret = btrfs_next_leaf(root, path);
 233                         if (ret == 1)
 234                                 found_next = 1;
 235                         if (ret != 0)
 236                                 goto insert;
 237                         slot = 0;
 238                 }
 239                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 240                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 241                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 242                         found_next = 1;
 243                         goto insert;
 244                 }
 245                 next_offset = found_key.offset;
 246                 found_next = 1;
 247                 goto insert;
 248         }
 249
 250         /*
 251          * at this point, we know the tree has an item, but it isn't big
 252          * enough yet to put our csum in.  Grow it
 253          */
 254         btrfs_release_path(path);
 255         ret = btrfs_search_slot(trans, root, &file_key, path,
 256                                 csum_size, 1);
 257         if (ret < 0)
 258                 goto fail;
 259         if (ret == 0) {
 260                 BUG();
 261         }
 262         if (path->slots[0] == 0) {
 263                 goto insert;
 264         }
 265         path->slots[0]--;
 266         leaf = path->nodes[0];
 267         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 268         csum_offset = (file_key.offset - found_key.offset) / root->sectorsize;
 269         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 270             found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 271             csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
 272                 goto insert;
 273         }
 274         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 275             csum_size) {
 276                 u32 diff = (csum_offset + 1) * csum_size;
 277                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 278                 if (diff != csum_size)
 279                         goto insert;
 280                 ret = btrfs_extend_item(trans, root, path, diff);
 281                 BUG_ON(ret);
 282                 goto csum;
 283         }
 284
 285 insert:
 286         btrfs_release_path(path);
 287         csum_offset = 0;
 288         if (found_next) {
 289                 u64 tmp = min(alloc_end, next_offset);
 290                 tmp -= file_key.offset;
 291                 tmp /= root->sectorsize;
 292                 tmp = max((u64)1, tmp);
 293                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
 294                 ins_size = csum_size * tmp;
 295         } else {
 296                 ins_size = csum_size;
 297         }
 298         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 299                                       ins_size);
 300         if (ret < 0)
 301                 goto fail;
 302         if (ret != 0) {
 303                 WARN_ON(1);
 304                 goto fail;
 305         }
 306 csum:
 307         leaf = path->nodes[0];
 308         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 309         ret = 0;
 310         item = (struct btrfs_csum_item *)((unsigned char *)item +
 311                                           csum_offset * csum_size);
 312 found:
 313         csum_result = btrfs_csum_data(root, data, csum_result, len);
 314         btrfs_csum_final(csum_result, (u8 *)&csum_result);
 315         if (csum_result == 0) {
 316                 printk("csum result is 0 for block %llu\n",
 317                        (unsigned long long)bytenr);
 318         }
 319
 320         write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 321                             csum_size);
 322         btrfs_mark_buffer_dirty(path->nodes[0]);
 323 fail:
 324         btrfs_free_path(path);
 325         return ret;
 326 }
 327
 328 /*
 329  * helper function for csum removal, this expects the
 330  * key to describe the csum pointed to by the path, and it expects
 331  * the csum to overlap the range [bytenr, len]
 332  *
 333  * The csum should not be entirely contained in the range and the
 334  * range should not be entirely contained in the csum.
 335  *
 336  * This calls btrfs_truncate_item with the correct args based on the
 337  * overlap, and fixes up the key as required.
 338  */
 339 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
 340                                       struct btrfs_root *root,
 341                                       struct btrfs_path *path,
 342                                       struct btrfs_key *key,
 343                                       u64 bytenr, u64 len)
 344 {
 345         struct extent_buffer *leaf;
 346         u16 csum_size =
 347                 btrfs_super_csum_size(root->fs_info->super_copy);
 348         u64 csum_end;
 349         u64 end_byte = bytenr + len;
 350         u32 blocksize = root->sectorsize;
 351         int ret;
 352
 353         leaf = path->nodes[0];
 354         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 355         csum_end *= root->sectorsize;
 356         csum_end += key->offset;
 357
 358         if (key->offset < bytenr && csum_end <= end_byte) {
 359                 /*
 360                  *         [ bytenr - len ]
 361                  *         [   ]
 362                  *   [csum     ]
 363                  *   A simple truncate off the end of the item
 364                  */
 365                 u32 new_size = (bytenr - key->offset) / blocksize;
 366                 new_size *= csum_size;
 367                 ret = btrfs_truncate_item(trans, root, path, new_size, 1);
 368                 BUG_ON(ret);
 369         } else if (key->offset >= bytenr && csum_end > end_byte &&
 370                    end_byte > key->offset) {
 371                 /*
 372                  *         [ bytenr - len ]
 373                  *                 [ ]
 374                  *                 [csum     ]
 375                  * we need to truncate from the beginning of the csum
 376                  */
 377                 u32 new_size = (csum_end - end_byte) / blocksize;
 378                 new_size *= csum_size;
 379
 380                 ret = btrfs_truncate_item(trans, root, path, new_size, 0);
 381                 BUG_ON(ret);
 382
 383                 key->offset = end_byte;
 384                 ret = btrfs_set_item_key_safe(root, path, key);
 385                 BUG_ON(ret);
 386         } else {
 387                 BUG();
 388         }
 389         return 0;
 390 }
 391
 392 /*
 393  * deletes the csum items from the csum tree for a given
 394  * range of bytes.
 395  */
 396 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 397                     struct btrfs_root *root, u64 bytenr, u64 len)
 398 {
 399         struct btrfs_path *path;
 400         struct btrfs_key key;
 401         u64 end_byte = bytenr + len;
 402         u64 csum_end;
 403         struct extent_buffer *leaf;
 404         int ret;
 405         u16 csum_size =
 406                 btrfs_super_csum_size(root->fs_info->super_copy);
 407         int blocksize = root->sectorsize;
 408
 409         root = root->fs_info->csum_root;
 410
 411         path = btrfs_alloc_path();
 412         if (!path)
 413                 return -ENOMEM;
 414
 415         while (1) {
 416                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 417                 key.offset = end_byte - 1;
 418                 key.type = BTRFS_EXTENT_CSUM_KEY;
 419
 420                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 421                 if (ret > 0) {
 422                         if (path->slots[0] == 0)
 423                                 goto out;
 424                         path->slots[0]--;
 425                 }
 426                 leaf = path->nodes[0];
 427                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 428
 429                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 430                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 431                         break;
 432                 }
 433
 434                 if (key.offset >= end_byte)
 435                         break;
 436
 437                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 438                 csum_end *= blocksize;
 439                 csum_end += key.offset;
 440
 441                 /* this csum ends before we start, we're done */
 442                 if (csum_end <= bytenr)
 443                         break;
 444
 445                 /* delete the entire item, it is inside our range */
 446                 if (key.offset >= bytenr && csum_end <= end_byte) {
 447                         ret = btrfs_del_item(trans, root, path);
 448                         BUG_ON(ret);
 449                 } else if (key.offset < bytenr && csum_end > end_byte) {
 450                         unsigned long offset;
 451                         unsigned long shift_len;
 452                         unsigned long item_offset;
 453                         /*
 454                          *        [ bytenr - len ]
 455                          *     [csum                ]
 456                          *
 457                          * Our bytes are in the middle of the csum,
 458                          * we need to split this item and insert a new one.
 459                          *
 460                          * But we can't drop the path because the
 461                          * csum could change, get removed, extended etc.
 462                          *
 463                          * The trick here is the max size of a csum item leaves
 464                          * enough room in the tree block for a single
 465                          * item header.  So, we split the item in place,
 466                          * adding a new header pointing to the existing
 467                          * bytes.  Then we loop around again and we have
 468                          * a nicely formed csum item that we can neatly
 469                          * truncate.
 470                          */
 471                         offset = (bytenr - key.offset) / blocksize;
 472                         offset *= csum_size;
 473
 474                         shift_len = (len / blocksize) * csum_size;
 475
 476                         item_offset = btrfs_item_ptr_offset(leaf,
 477                                                             path->slots[0]);
 478
 479                         memset_extent_buffer(leaf, 0, item_offset + offset,
 480                                              shift_len);
 481                         key.offset = bytenr;
 482
 483                         /*
 484                          * btrfs_split_item returns -EAGAIN when the
 485                          * item changed size or key
 486                          */
 487                         ret = btrfs_split_item(trans, root, path, &key, offset);
 488                         BUG_ON(ret && ret != -EAGAIN);
 489
 490                         key.offset = end_byte - 1;
 491                 } else {
 492                         ret = truncate_one_csum(trans, root, path,
 493                                                 &key, bytenr, len);
 494                         BUG_ON(ret);
 495                 }
 496                 btrfs_release_path(path);
 497         }
 498 out:
 499         btrfs_free_path(path);
 500         return 0;
 501 }