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->fs_info) - \
  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, const 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) /
 166                                 root->fs_info->sectorsize;
 167                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 168                 csums_in_item /= csum_size;
 169
 170                 if (csum_offset >= csums_in_item) {
 171                         ret = -EFBIG;
 172                         goto fail;
 173                 }
 174         }
 175         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 176         item = (struct btrfs_csum_item *)((unsigned char *)item +
 177                                           csum_offset * csum_size);
 178         return item;
 179 fail:
 180         if (ret > 0)
 181                 ret = -ENOENT;
 182         return ERR_PTR(ret);
 183 }
 184
 185 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 186                           struct btrfs_root *root, u64 alloc_end,
 187                           u64 bytenr, char *data, size_t len)
 188 {
 189         int ret = 0;
 190         struct btrfs_key file_key;
 191         struct btrfs_key found_key;
 192         u64 next_offset = (u64)-1;
 193         int found_next = 0;
 194         struct btrfs_path *path;
 195         struct btrfs_csum_item *item;
 196         struct extent_buffer *leaf = NULL;
 197         u64 csum_offset;
 198         u32 csum_result = ~(u32)0;
 199         u32 sectorsize = root->fs_info->sectorsize;
 200         u32 nritems;
 201         u32 ins_size;
 202         u16 csum_size =
 203                 btrfs_super_csum_size(root->fs_info->super_copy);
 204
 205         path = btrfs_alloc_path();
 206         if (!path)
 207                 return -ENOMEM;
 208
 209         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 210         file_key.offset = bytenr;
 211         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 212
 213         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 214         if (!IS_ERR(item)) {
 215                 leaf = path->nodes[0];
 216                 ret = 0;
 217                 goto found;
 218         }
 219         ret = PTR_ERR(item);
 220         if (ret == -EFBIG) {
 221                 u32 item_size;
 222                 /* we found one, but it isn't big enough yet */
 223                 leaf = path->nodes[0];
 224                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 225                 if ((item_size / csum_size) >= MAX_CSUM_ITEMS(root, csum_size)) {
 226                         /* already at max size, make a new one */
 227                         goto insert;
 228                 }
 229         } else {
 230                 int slot = path->slots[0] + 1;
 231                 /* we didn't find a csum item, insert one */
 232                 nritems = btrfs_header_nritems(path->nodes[0]);
 233                 if (path->slots[0] >= nritems - 1) {
 234                         ret = btrfs_next_leaf(root, path);
 235                         if (ret == 1)
 236                                 found_next = 1;
 237                         if (ret != 0)
 238                                 goto insert;
 239                         slot = 0;
 240                 }
 241                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 242                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 243                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 244                         found_next = 1;
 245                         goto insert;
 246                 }
 247                 next_offset = found_key.offset;
 248                 found_next = 1;
 249                 goto insert;
 250         }
 251
 252         /*
 253          * at this point, we know the tree has an item, but it isn't big
 254          * enough yet to put our csum in.  Grow it
 255          */
 256         btrfs_release_path(path);
 257         ret = btrfs_search_slot(trans, root, &file_key, path,
 258                                 csum_size, 1);
 259         if (ret < 0)
 260                 goto fail;
 261         if (ret == 0) {
 262                 BUG();
 263         }
 264         if (path->slots[0] == 0) {
 265                 goto insert;
 266         }
 267         path->slots[0]--;
 268         leaf = path->nodes[0];
 269         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 270         csum_offset = (file_key.offset - found_key.offset) / sectorsize;
 271         if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 272             found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 273             csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) {
 274                 goto insert;
 275         }
 276         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 277             csum_size) {
 278                 u32 diff = (csum_offset + 1) * csum_size;
 279                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 280                 if (diff != csum_size)
 281                         goto insert;
 282                 ret = btrfs_extend_item(root, path, diff);
 283                 BUG_ON(ret);
 284                 goto csum;
 285         }
 286
 287 insert:
 288         btrfs_release_path(path);
 289         csum_offset = 0;
 290         if (found_next) {
 291                 u64 tmp = min(alloc_end, next_offset);
 292                 tmp -= file_key.offset;
 293                 tmp /= sectorsize;
 294                 tmp = max((u64)1, tmp);
 295                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size));
 296                 ins_size = csum_size * tmp;
 297         } else {
 298                 ins_size = csum_size;
 299         }
 300         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 301                                       ins_size);
 302         if (ret < 0)
 303                 goto fail;
 304         if (ret != 0) {
 305                 WARN_ON(1);
 306                 goto fail;
 307         }
 308 csum:
 309         leaf = path->nodes[0];
 310         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 311         ret = 0;
 312         item = (struct btrfs_csum_item *)((unsigned char *)item +
 313                                           csum_offset * csum_size);
 314 found:
 315         csum_result = btrfs_csum_data(data, csum_result, len);
 316         btrfs_csum_final(csum_result, (u8 *)&csum_result);
 317         if (csum_result == 0) {
 318                 printk("csum result is 0 for block %llu\n",
 319                        (unsigned long long)bytenr);
 320         }
 321
 322         write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 323                             csum_size);
 324         btrfs_mark_buffer_dirty(path->nodes[0]);
 325 fail:
 326         btrfs_free_path(path);
 327         return ret;
 328 }
 329
 330 /*
 331  * helper function for csum removal, this expects the
 332  * key to describe the csum pointed to by the path, and it expects
 333  * the csum to overlap the range [bytenr, len]
 334  *
 335  * The csum should not be entirely contained in the range and the
 336  * range should not be entirely contained in the csum.
 337  *
 338  * This calls btrfs_truncate_item with the correct args based on the
 339  * overlap, and fixes up the key as required.
 340  */
 341 static noinline int truncate_one_csum(struct btrfs_root *root,
 342                                       struct btrfs_path *path,
 343                                       struct btrfs_key *key,
 344                                       u64 bytenr, u64 len)
 345 {
 346         struct extent_buffer *leaf;
 347         u16 csum_size =
 348                 btrfs_super_csum_size(root->fs_info->super_copy);
 349         u64 csum_end;
 350         u64 end_byte = bytenr + len;
 351         u32 blocksize = root->fs_info->sectorsize;
 352         int ret;
 353
 354         leaf = path->nodes[0];
 355         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 356         csum_end *= root->fs_info->sectorsize;
 357         csum_end += key->offset;
 358
 359         if (key->offset < bytenr && csum_end <= end_byte) {
 360                 /*
 361                  *         [ bytenr - len ]
 362                  *         [   ]
 363                  *   [csum     ]
 364                  *   A simple truncate off the end of the item
 365                  */
 366                 u32 new_size = (bytenr - key->offset) / blocksize;
 367                 new_size *= csum_size;
 368                 ret = btrfs_truncate_item(root, path, new_size, 1);
 369                 BUG_ON(ret);
 370         } else if (key->offset >= bytenr && csum_end > end_byte &&
 371                    end_byte > key->offset) {
 372                 /*
 373                  *         [ bytenr - len ]
 374                  *                 [ ]
 375                  *                 [csum     ]
 376                  * we need to truncate from the beginning of the csum
 377                  */
 378                 u32 new_size = (csum_end - end_byte) / blocksize;
 379                 new_size *= csum_size;
 380
 381                 ret = btrfs_truncate_item(root, path, new_size, 0);
 382                 BUG_ON(ret);
 383
 384                 key->offset = end_byte;
 385                 ret = btrfs_set_item_key_safe(root, path, key);
 386                 BUG_ON(ret);
 387         } else {
 388                 BUG();
 389         }
 390         return 0;
 391 }
 392
 393 /*
 394  * deletes the csum items from the csum tree for a given
 395  * range of bytes.
 396  */
 397 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 398                     struct btrfs_root *root, u64 bytenr, u64 len)
 399 {
 400         struct btrfs_path *path;
 401         struct btrfs_key key;
 402         u64 end_byte = bytenr + len;
 403         u64 csum_end;
 404         struct extent_buffer *leaf;
 405         int ret;
 406         u16 csum_size =
 407                 btrfs_super_csum_size(root->fs_info->super_copy);
 408         int blocksize = root->fs_info->sectorsize;
 409
 410         root = root->fs_info->csum_root;
 411
 412         path = btrfs_alloc_path();
 413         if (!path)
 414                 return -ENOMEM;
 415
 416         while (1) {
 417                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 418                 key.offset = end_byte - 1;
 419                 key.type = BTRFS_EXTENT_CSUM_KEY;
 420
 421                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 422                 if (ret > 0) {
 423                         if (path->slots[0] == 0)
 424                                 goto out;
 425                         path->slots[0]--;
 426                 }
 427                 leaf = path->nodes[0];
 428                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 429
 430                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 431                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 432                         break;
 433                 }
 434
 435                 if (key.offset >= end_byte)
 436                         break;
 437
 438                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 439                 csum_end *= blocksize;
 440                 csum_end += key.offset;
 441
 442                 /* this csum ends before we start, we're done */
 443                 if (csum_end <= bytenr)
 444                         break;
 445
 446                 /* delete the entire item, it is inside our range */
 447                 if (key.offset >= bytenr && csum_end <= end_byte) {
 448                         ret = btrfs_del_item(trans, root, path);
 449                         BUG_ON(ret);
 450                 } else if (key.offset < bytenr && csum_end > end_byte) {
 451                         unsigned long offset;
 452                         unsigned long shift_len;
 453                         unsigned long item_offset;
 454                         /*
 455                          *        [ bytenr - len ]
 456                          *     [csum                ]
 457                          *
 458                          * Our bytes are in the middle of the csum,
 459                          * we need to split this item and insert a new one.
 460                          *
 461                          * But we can't drop the path because the
 462                          * csum could change, get removed, extended etc.
 463                          *
 464                          * The trick here is the max size of a csum item leaves
 465                          * enough room in the tree block for a single
 466                          * item header.  So, we split the item in place,
 467                          * adding a new header pointing to the existing
 468                          * bytes.  Then we loop around again and we have
 469                          * a nicely formed csum item that we can neatly
 470                          * truncate.
 471                          */
 472                         offset = (bytenr - key.offset) / blocksize;
 473                         offset *= csum_size;
 474
 475                         shift_len = (len / blocksize) * csum_size;
 476
 477                         item_offset = btrfs_item_ptr_offset(leaf,
 478                                                             path->slots[0]);
 479
 480                         memset_extent_buffer(leaf, 0, item_offset + offset,
 481                                              shift_len);
 482                         key.offset = bytenr;
 483
 484                         /*
 485                          * btrfs_split_item returns -EAGAIN when the
 486                          * item changed size or key
 487                          */
 488                         ret = btrfs_split_item(trans, root, path, &key, offset);
 489                         BUG_ON(ret && ret != -EAGAIN);
 490
 491                         key.offset = end_byte - 1;
 492                 } else {
 493                         ret = truncate_one_csum(root, path, &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 }