fs/btrfs/file-item.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/bio.h>
   7 #include <linux/slab.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/highmem.h>
  10 #include "ctree.h"
  11 #include "disk-io.h"
  12 #include "transaction.h"
  13 #include "volumes.h"
  14 #include "print-tree.h"
  15 #include "compression.h"
  16
  17 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  18                                    sizeof(struct btrfs_item) * 2) / \
  19                                   size) - 1))
  20
  21 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  22                                        PAGE_SIZE))
  23
  24 #define MAX_ORDERED_SUM_BYTES(fs_info) ((PAGE_SIZE - \
  25                                    sizeof(struct btrfs_ordered_sum)) / \
  26                                    sizeof(u32) * (fs_info)->sectorsize)
  27
  28 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  29                              struct btrfs_root *root,
  30                              u64 objectid, u64 pos,
  31                              u64 disk_offset, u64 disk_num_bytes,
  32                              u64 num_bytes, u64 offset, u64 ram_bytes,
  33                              u8 compression, u8 encryption, u16 other_encoding)
  34 {
  35         int ret = 0;
  36         struct btrfs_file_extent_item *item;
  37         struct btrfs_key file_key;
  38         struct btrfs_path *path;
  39         struct extent_buffer *leaf;
  40
  41         path = btrfs_alloc_path();
  42         if (!path)
  43                 return -ENOMEM;
  44         file_key.objectid = objectid;
  45         file_key.offset = pos;
  46         file_key.type = BTRFS_EXTENT_DATA_KEY;
  47
  48         path->leave_spinning = 1;
  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); /* Can't happen */
  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, disk_offset);
  58         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  59         btrfs_set_file_extent_offset(leaf, item, offset);
  60         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  61         btrfs_set_file_extent_ram_bytes(leaf, item, ram_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, compression);
  65         btrfs_set_file_extent_encryption(leaf, item, encryption);
  66         btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
  67
  68         btrfs_mark_buffer_dirty(leaf);
  69 out:
  70         btrfs_free_path(path);
  71         return ret;
  72 }
  73
  74 static struct btrfs_csum_item *
  75 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  76                   struct btrfs_root *root,
  77                   struct btrfs_path *path,
  78                   u64 bytenr, int cow)
  79 {
  80         struct btrfs_fs_info *fs_info = root->fs_info;
  81         int ret;
  82         struct btrfs_key file_key;
  83         struct btrfs_key found_key;
  84         struct btrfs_csum_item *item;
  85         struct extent_buffer *leaf;
  86         u64 csum_offset = 0;
  87         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
  88         int csums_in_item;
  89
  90         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
  91         file_key.offset = bytenr;
  92         file_key.type = BTRFS_EXTENT_CSUM_KEY;
  93         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
  94         if (ret < 0)
  95                 goto fail;
  96         leaf = path->nodes[0];
  97         if (ret > 0) {
  98                 ret = 1;
  99                 if (path->slots[0] == 0)
 100                         goto fail;
 101                 path->slots[0]--;
 102                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 103                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 104                         goto fail;
 105
 106                 csum_offset = (bytenr - found_key.offset) >>
 107                                 fs_info->sb->s_blocksize_bits;
 108                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 109                 csums_in_item /= csum_size;
 110
 111                 if (csum_offset == csums_in_item) {
 112                         ret = -EFBIG;
 113                         goto fail;
 114                 } else if (csum_offset > csums_in_item) {
 115                         goto fail;
 116                 }
 117         }
 118         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 119         item = (struct btrfs_csum_item *)((unsigned char *)item +
 120                                           csum_offset * csum_size);
 121         return item;
 122 fail:
 123         if (ret > 0)
 124                 ret = -ENOENT;
 125         return ERR_PTR(ret);
 126 }
 127
 128 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 129                              struct btrfs_root *root,
 130                              struct btrfs_path *path, u64 objectid,
 131                              u64 offset, int mod)
 132 {
 133         int ret;
 134         struct btrfs_key file_key;
 135         int ins_len = mod < 0 ? -1 : 0;
 136         int cow = mod != 0;
 137
 138         file_key.objectid = objectid;
 139         file_key.offset = offset;
 140         file_key.type = BTRFS_EXTENT_DATA_KEY;
 141         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 142         return ret;
 143 }
 144
 145 static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 146                                    u64 logical_offset, u32 *dst, int dio)
 147 {
 148         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 149         struct bio_vec bvec;
 150         struct bvec_iter iter;
 151         struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);
 152         struct btrfs_csum_item *item = NULL;
 153         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 154         struct btrfs_path *path;
 155         u8 *csum;
 156         u64 offset = 0;
 157         u64 item_start_offset = 0;
 158         u64 item_last_offset = 0;
 159         u64 disk_bytenr;
 160         u64 page_bytes_left;
 161         u32 diff;
 162         int nblocks;
 163         int count = 0;
 164         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 165
 166         path = btrfs_alloc_path();
 167         if (!path)
 168                 return BLK_STS_RESOURCE;
 169
 170         nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits;
 171         if (!dst) {
 172                 if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 173                         btrfs_bio->csum = kmalloc_array(nblocks, csum_size,
 174                                                         GFP_NOFS);
 175                         if (!btrfs_bio->csum) {
 176                                 btrfs_free_path(path);
 177                                 return BLK_STS_RESOURCE;
 178                         }
 179                 } else {
 180                         btrfs_bio->csum = btrfs_bio->csum_inline;
 181                 }
 182                 csum = btrfs_bio->csum;
 183         } else {
 184                 csum = (u8 *)dst;
 185         }
 186
 187         if (bio->bi_iter.bi_size > PAGE_SIZE * 8)
 188                 path->reada = READA_FORWARD;
 189
 190         /*
 191          * the free space stuff is only read when it hasn't been
 192          * updated in the current transaction.  So, we can safely
 193          * read from the commit root and sidestep a nasty deadlock
 194          * between reading the free space cache and updating the csum tree.
 195          */
 196         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 197                 path->search_commit_root = 1;
 198                 path->skip_locking = 1;
 199         }
 200
 201         disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
 202         if (dio)
 203                 offset = logical_offset;
 204
 205         bio_for_each_segment(bvec, bio, iter) {
 206                 page_bytes_left = bvec.bv_len;
 207                 if (count)
 208                         goto next;
 209
 210                 if (!dio)
 211                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 212                 count = btrfs_find_ordered_sum(inode, offset, disk_bytenr,
 213                                                (u32 *)csum, nblocks);
 214                 if (count)
 215                         goto found;
 216
 217                 if (!item || disk_bytenr < item_start_offset ||
 218                     disk_bytenr >= item_last_offset) {
 219                         struct btrfs_key found_key;
 220                         u32 item_size;
 221
 222                         if (item)
 223                                 btrfs_release_path(path);
 224                         item = btrfs_lookup_csum(NULL, fs_info->csum_root,
 225                                                  path, disk_bytenr, 0);
 226                         if (IS_ERR(item)) {
 227                                 count = 1;
 228                                 memset(csum, 0, csum_size);
 229                                 if (BTRFS_I(inode)->root->root_key.objectid ==
 230                                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 231                                         set_extent_bits(io_tree, offset,
 232                                                 offset + fs_info->sectorsize - 1,
 233                                                 EXTENT_NODATASUM);
 234                                 } else {
 235                                         btrfs_info_rl(fs_info,
 236                                                    "no csum found for inode %llu start %llu",
 237                                                btrfs_ino(BTRFS_I(inode)), offset);
 238                                 }
 239                                 item = NULL;
 240                                 btrfs_release_path(path);
 241                                 goto found;
 242                         }
 243                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 244                                               path->slots[0]);
 245
 246                         item_start_offset = found_key.offset;
 247                         item_size = btrfs_item_size_nr(path->nodes[0],
 248                                                        path->slots[0]);
 249                         item_last_offset = item_start_offset +
 250                                 (item_size / csum_size) *
 251                                 fs_info->sectorsize;
 252                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 253                                               struct btrfs_csum_item);
 254                 }
 255                 /*
 256                  * this byte range must be able to fit inside
 257                  * a single leaf so it will also fit inside a u32
 258                  */
 259                 diff = disk_bytenr - item_start_offset;
 260                 diff = diff / fs_info->sectorsize;
 261                 diff = diff * csum_size;
 262                 count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >>
 263                                             inode->i_sb->s_blocksize_bits);
 264                 read_extent_buffer(path->nodes[0], csum,
 265                                    ((unsigned long)item) + diff,
 266                                    csum_size * count);
 267 found:
 268                 csum += count * csum_size;
 269                 nblocks -= count;
 270 next:
 271                 while (count--) {
 272                         disk_bytenr += fs_info->sectorsize;
 273                         offset += fs_info->sectorsize;
 274                         page_bytes_left -= fs_info->sectorsize;
 275                         if (!page_bytes_left)
 276                                 break; /* move to next bio */
 277                 }
 278         }
 279
 280         WARN_ON_ONCE(count);
 281         btrfs_free_path(path);
 282         return 0;
 283 }
 284
 285 blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u32 *dst)
 286 {
 287         return __btrfs_lookup_bio_sums(inode, bio, 0, dst, 0);
 288 }
 289
 290 blk_status_t btrfs_lookup_bio_sums_dio(struct inode *inode, struct bio *bio, u64 offset)
 291 {
 292         return __btrfs_lookup_bio_sums(inode, bio, offset, NULL, 1);
 293 }
 294
 295 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 296                              struct list_head *list, int search_commit)
 297 {
 298         struct btrfs_fs_info *fs_info = root->fs_info;
 299         struct btrfs_key key;
 300         struct btrfs_path *path;
 301         struct extent_buffer *leaf;
 302         struct btrfs_ordered_sum *sums;
 303         struct btrfs_csum_item *item;
 304         LIST_HEAD(tmplist);
 305         unsigned long offset;
 306         int ret;
 307         size_t size;
 308         u64 csum_end;
 309         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 310
 311         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 312                IS_ALIGNED(end + 1, fs_info->sectorsize));
 313
 314         path = btrfs_alloc_path();
 315         if (!path)
 316                 return -ENOMEM;
 317
 318         if (search_commit) {
 319                 path->skip_locking = 1;
 320                 path->reada = READA_FORWARD;
 321                 path->search_commit_root = 1;
 322         }
 323
 324         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 325         key.offset = start;
 326         key.type = BTRFS_EXTENT_CSUM_KEY;
 327
 328         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 329         if (ret < 0)
 330                 goto fail;
 331         if (ret > 0 && path->slots[0] > 0) {
 332                 leaf = path->nodes[0];
 333                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 334                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 335                     key.type == BTRFS_EXTENT_CSUM_KEY) {
 336                         offset = (start - key.offset) >>
 337                                  fs_info->sb->s_blocksize_bits;
 338                         if (offset * csum_size <
 339                             btrfs_item_size_nr(leaf, path->slots[0] - 1))
 340                                 path->slots[0]--;
 341                 }
 342         }
 343
 344         while (start <= end) {
 345                 leaf = path->nodes[0];
 346                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 347                         ret = btrfs_next_leaf(root, path);
 348                         if (ret < 0)
 349                                 goto fail;
 350                         if (ret > 0)
 351                                 break;
 352                         leaf = path->nodes[0];
 353                 }
 354
 355                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 356                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 357                     key.type != BTRFS_EXTENT_CSUM_KEY ||
 358                     key.offset > end)
 359                         break;
 360
 361                 if (key.offset > start)
 362                         start = key.offset;
 363
 364                 size = btrfs_item_size_nr(leaf, path->slots[0]);
 365                 csum_end = key.offset + (size / csum_size) * fs_info->sectorsize;
 366                 if (csum_end <= start) {
 367                         path->slots[0]++;
 368                         continue;
 369                 }
 370
 371                 csum_end = min(csum_end, end + 1);
 372                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 373                                       struct btrfs_csum_item);
 374                 while (start < csum_end) {
 375                         size = min_t(size_t, csum_end - start,
 376                                      MAX_ORDERED_SUM_BYTES(fs_info));
 377                         sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 378                                        GFP_NOFS);
 379                         if (!sums) {
 380                                 ret = -ENOMEM;
 381                                 goto fail;
 382                         }
 383
 384                         sums->bytenr = start;
 385                         sums->len = (int)size;
 386
 387                         offset = (start - key.offset) >>
 388                                 fs_info->sb->s_blocksize_bits;
 389                         offset *= csum_size;
 390                         size >>= fs_info->sb->s_blocksize_bits;
 391
 392                         read_extent_buffer(path->nodes[0],
 393                                            sums->sums,
 394                                            ((unsigned long)item) + offset,
 395                                            csum_size * size);
 396
 397                         start += fs_info->sectorsize * size;
 398                         list_add_tail(&sums->list, &tmplist);
 399                 }
 400                 path->slots[0]++;
 401         }
 402         ret = 0;
 403 fail:
 404         while (ret < 0 && !list_empty(&tmplist)) {
 405                 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 406                 list_del(&sums->list);
 407                 kfree(sums);
 408         }
 409         list_splice_tail(&tmplist, list);
 410
 411         btrfs_free_path(path);
 412         return ret;
 413 }
 414
 415 blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio,
 416                        u64 file_start, int contig)
 417 {
 418         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 419         struct btrfs_ordered_sum *sums;
 420         struct btrfs_ordered_extent *ordered = NULL;
 421         char *data;
 422         struct bvec_iter iter;
 423         struct bio_vec bvec;
 424         int index;
 425         int nr_sectors;
 426         unsigned long total_bytes = 0;
 427         unsigned long this_sum_bytes = 0;
 428         int i;
 429         u64 offset;
 430
 431         sums = kzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 432                        GFP_NOFS);
 433         if (!sums)
 434                 return BLK_STS_RESOURCE;
 435
 436         sums->len = bio->bi_iter.bi_size;
 437         INIT_LIST_HEAD(&sums->list);
 438
 439         if (contig)
 440                 offset = file_start;
 441         else
 442                 offset = 0; /* shut up gcc */
 443
 444         sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;
 445         index = 0;
 446
 447         bio_for_each_segment(bvec, bio, iter) {
 448                 if (!contig)
 449                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 450
 451                 if (!ordered) {
 452                         ordered = btrfs_lookup_ordered_extent(inode, offset);
 453                         BUG_ON(!ordered); /* Logic error */
 454                 }
 455
 456                 data = kmap_atomic(bvec.bv_page);
 457
 458                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
 459                                                  bvec.bv_len + fs_info->sectorsize
 460                                                  - 1);
 461
 462                 for (i = 0; i < nr_sectors; i++) {
 463                         if (offset >= ordered->file_offset + ordered->len ||
 464                                 offset < ordered->file_offset) {
 465                                 unsigned long bytes_left;
 466
 467                                 kunmap_atomic(data);
 468                                 sums->len = this_sum_bytes;
 469                                 this_sum_bytes = 0;
 470                                 btrfs_add_ordered_sum(inode, ordered, sums);
 471                                 btrfs_put_ordered_extent(ordered);
 472
 473                                 bytes_left = bio->bi_iter.bi_size - total_bytes;
 474
 475                                 sums = kzalloc(btrfs_ordered_sum_size(fs_info, bytes_left),
 476                                                GFP_NOFS);
 477                                 BUG_ON(!sums); /* -ENOMEM */
 478                                 sums->len = bytes_left;
 479                                 ordered = btrfs_lookup_ordered_extent(inode,
 480                                                                 offset);
 481                                 ASSERT(ordered); /* Logic error */
 482                                 sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9)
 483                                         + total_bytes;
 484                                 index = 0;
 485
 486                                 data = kmap_atomic(bvec.bv_page);
 487                         }
 488
 489                         sums->sums[index] = ~(u32)0;
 490                         sums->sums[index]
 491                                 = btrfs_csum_data(data + bvec.bv_offset
 492                                                 + (i * fs_info->sectorsize),
 493                                                 sums->sums[index],
 494                                                 fs_info->sectorsize);
 495                         btrfs_csum_final(sums->sums[index],
 496                                         (char *)(sums->sums + index));
 497                         index++;
 498                         offset += fs_info->sectorsize;
 499                         this_sum_bytes += fs_info->sectorsize;
 500                         total_bytes += fs_info->sectorsize;
 501                 }
 502
 503                 kunmap_atomic(data);
 504         }
 505         this_sum_bytes = 0;
 506         btrfs_add_ordered_sum(inode, ordered, sums);
 507         btrfs_put_ordered_extent(ordered);
 508         return 0;
 509 }
 510
 511 /*
 512  * helper function for csum removal, this expects the
 513  * key to describe the csum pointed to by the path, and it expects
 514  * the csum to overlap the range [bytenr, len]
 515  *
 516  * The csum should not be entirely contained in the range and the
 517  * range should not be entirely contained in the csum.
 518  *
 519  * This calls btrfs_truncate_item with the correct args based on the
 520  * overlap, and fixes up the key as required.
 521  */
 522 static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 523                                        struct btrfs_path *path,
 524                                        struct btrfs_key *key,
 525                                        u64 bytenr, u64 len)
 526 {
 527         struct extent_buffer *leaf;
 528         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 529         u64 csum_end;
 530         u64 end_byte = bytenr + len;
 531         u32 blocksize_bits = fs_info->sb->s_blocksize_bits;
 532
 533         leaf = path->nodes[0];
 534         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 535         csum_end <<= fs_info->sb->s_blocksize_bits;
 536         csum_end += key->offset;
 537
 538         if (key->offset < bytenr && csum_end <= end_byte) {
 539                 /*
 540                  *         [ bytenr - len ]
 541                  *         [   ]
 542                  *   [csum     ]
 543                  *   A simple truncate off the end of the item
 544                  */
 545                 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 546                 new_size *= csum_size;
 547                 btrfs_truncate_item(fs_info, path, new_size, 1);
 548         } else if (key->offset >= bytenr && csum_end > end_byte &&
 549                    end_byte > key->offset) {
 550                 /*
 551                  *         [ bytenr - len ]
 552                  *                 [ ]
 553                  *                 [csum     ]
 554                  * we need to truncate from the beginning of the csum
 555                  */
 556                 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 557                 new_size *= csum_size;
 558
 559                 btrfs_truncate_item(fs_info, path, new_size, 0);
 560
 561                 key->offset = end_byte;
 562                 btrfs_set_item_key_safe(fs_info, path, key);
 563         } else {
 564                 BUG();
 565         }
 566 }
 567
 568 /*
 569  * deletes the csum items from the csum tree for a given
 570  * range of bytes.
 571  */
 572 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 573                     struct btrfs_fs_info *fs_info, u64 bytenr, u64 len)
 574 {
 575         struct btrfs_root *root = fs_info->csum_root;
 576         struct btrfs_path *path;
 577         struct btrfs_key key;
 578         u64 end_byte = bytenr + len;
 579         u64 csum_end;
 580         struct extent_buffer *leaf;
 581         int ret;
 582         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 583         int blocksize_bits = fs_info->sb->s_blocksize_bits;
 584
 585         path = btrfs_alloc_path();
 586         if (!path)
 587                 return -ENOMEM;
 588
 589         while (1) {
 590                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 591                 key.offset = end_byte - 1;
 592                 key.type = BTRFS_EXTENT_CSUM_KEY;
 593
 594                 path->leave_spinning = 1;
 595                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 596                 if (ret > 0) {
 597                         if (path->slots[0] == 0)
 598                                 break;
 599                         path->slots[0]--;
 600                 } else if (ret < 0) {
 601                         break;
 602                 }
 603
 604                 leaf = path->nodes[0];
 605                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 606
 607                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 608                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 609                         break;
 610                 }
 611
 612                 if (key.offset >= end_byte)
 613                         break;
 614
 615                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 616                 csum_end <<= blocksize_bits;
 617                 csum_end += key.offset;
 618
 619                 /* this csum ends before we start, we're done */
 620                 if (csum_end <= bytenr)
 621                         break;
 622
 623                 /* delete the entire item, it is inside our range */
 624                 if (key.offset >= bytenr && csum_end <= end_byte) {
 625                         int del_nr = 1;
 626
 627                         /*
 628                          * Check how many csum items preceding this one in this
 629                          * leaf correspond to our range and then delete them all
 630                          * at once.
 631                          */
 632                         if (key.offset > bytenr && path->slots[0] > 0) {
 633                                 int slot = path->slots[0] - 1;
 634
 635                                 while (slot >= 0) {
 636                                         struct btrfs_key pk;
 637
 638                                         btrfs_item_key_to_cpu(leaf, &pk, slot);
 639                                         if (pk.offset < bytenr ||
 640                                             pk.type != BTRFS_EXTENT_CSUM_KEY ||
 641                                             pk.objectid !=
 642                                             BTRFS_EXTENT_CSUM_OBJECTID)
 643                                                 break;
 644                                         path->slots[0] = slot;
 645                                         del_nr++;
 646                                         key.offset = pk.offset;
 647                                         slot--;
 648                                 }
 649                         }
 650                         ret = btrfs_del_items(trans, root, path,
 651                                               path->slots[0], del_nr);
 652                         if (ret)
 653                                 goto out;
 654                         if (key.offset == bytenr)
 655                                 break;
 656                 } else if (key.offset < bytenr && csum_end > end_byte) {
 657                         unsigned long offset;
 658                         unsigned long shift_len;
 659                         unsigned long item_offset;
 660                         /*
 661                          *        [ bytenr - len ]
 662                          *     [csum                ]
 663                          *
 664                          * Our bytes are in the middle of the csum,
 665                          * we need to split this item and insert a new one.
 666                          *
 667                          * But we can't drop the path because the
 668                          * csum could change, get removed, extended etc.
 669                          *
 670                          * The trick here is the max size of a csum item leaves
 671                          * enough room in the tree block for a single
 672                          * item header.  So, we split the item in place,
 673                          * adding a new header pointing to the existing
 674                          * bytes.  Then we loop around again and we have
 675                          * a nicely formed csum item that we can neatly
 676                          * truncate.
 677                          */
 678                         offset = (bytenr - key.offset) >> blocksize_bits;
 679                         offset *= csum_size;
 680
 681                         shift_len = (len >> blocksize_bits) * csum_size;
 682
 683                         item_offset = btrfs_item_ptr_offset(leaf,
 684                                                             path->slots[0]);
 685
 686                         memzero_extent_buffer(leaf, item_offset + offset,
 687                                              shift_len);
 688                         key.offset = bytenr;
 689
 690                         /*
 691                          * btrfs_split_item returns -EAGAIN when the
 692                          * item changed size or key
 693                          */
 694                         ret = btrfs_split_item(trans, root, path, &key, offset);
 695                         if (ret && ret != -EAGAIN) {
 696                                 btrfs_abort_transaction(trans, ret);
 697                                 goto out;
 698                         }
 699
 700                         key.offset = end_byte - 1;
 701                 } else {
 702                         truncate_one_csum(fs_info, path, &key, bytenr, len);
 703                         if (key.offset < bytenr)
 704                                 break;
 705                 }
 706                 btrfs_release_path(path);
 707         }
 708         ret = 0;
 709 out:
 710         btrfs_free_path(path);
 711         return ret;
 712 }
 713
 714 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 715                            struct btrfs_root *root,
 716                            struct btrfs_ordered_sum *sums)
 717 {
 718         struct btrfs_fs_info *fs_info = root->fs_info;
 719         struct btrfs_key file_key;
 720         struct btrfs_key found_key;
 721         struct btrfs_path *path;
 722         struct btrfs_csum_item *item;
 723         struct btrfs_csum_item *item_end;
 724         struct extent_buffer *leaf = NULL;
 725         u64 next_offset;
 726         u64 total_bytes = 0;
 727         u64 csum_offset;
 728         u64 bytenr;
 729         u32 nritems;
 730         u32 ins_size;
 731         int index = 0;
 732         int found_next;
 733         int ret;
 734         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 735
 736         path = btrfs_alloc_path();
 737         if (!path)
 738                 return -ENOMEM;
 739 again:
 740         next_offset = (u64)-1;
 741         found_next = 0;
 742         bytenr = sums->bytenr + total_bytes;
 743         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 744         file_key.offset = bytenr;
 745         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 746
 747         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 748         if (!IS_ERR(item)) {
 749                 ret = 0;
 750                 leaf = path->nodes[0];
 751                 item_end = btrfs_item_ptr(leaf, path->slots[0],
 752                                           struct btrfs_csum_item);
 753                 item_end = (struct btrfs_csum_item *)((char *)item_end +
 754                            btrfs_item_size_nr(leaf, path->slots[0]));
 755                 goto found;
 756         }
 757         ret = PTR_ERR(item);
 758         if (ret != -EFBIG && ret != -ENOENT)
 759                 goto fail_unlock;
 760
 761         if (ret == -EFBIG) {
 762                 u32 item_size;
 763                 /* we found one, but it isn't big enough yet */
 764                 leaf = path->nodes[0];
 765                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 766                 if ((item_size / csum_size) >=
 767                     MAX_CSUM_ITEMS(fs_info, csum_size)) {
 768                         /* already at max size, make a new one */
 769                         goto insert;
 770                 }
 771         } else {
 772                 int slot = path->slots[0] + 1;
 773                 /* we didn't find a csum item, insert one */
 774                 nritems = btrfs_header_nritems(path->nodes[0]);
 775                 if (!nritems || (path->slots[0] >= nritems - 1)) {
 776                         ret = btrfs_next_leaf(root, path);
 777                         if (ret == 1)
 778                                 found_next = 1;
 779                         if (ret != 0)
 780                                 goto insert;
 781                         slot = path->slots[0];
 782                 }
 783                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 784                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 785                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 786                         found_next = 1;
 787                         goto insert;
 788                 }
 789                 next_offset = found_key.offset;
 790                 found_next = 1;
 791                 goto insert;
 792         }
 793
 794         /*
 795          * at this point, we know the tree has an item, but it isn't big
 796          * enough yet to put our csum in.  Grow it
 797          */
 798         btrfs_release_path(path);
 799         ret = btrfs_search_slot(trans, root, &file_key, path,
 800                                 csum_size, 1);
 801         if (ret < 0)
 802                 goto fail_unlock;
 803
 804         if (ret > 0) {
 805                 if (path->slots[0] == 0)
 806                         goto insert;
 807                 path->slots[0]--;
 808         }
 809
 810         leaf = path->nodes[0];
 811         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 812         csum_offset = (bytenr - found_key.offset) >>
 813                         fs_info->sb->s_blocksize_bits;
 814
 815         if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 816             found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 817             csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
 818                 goto insert;
 819         }
 820
 821         if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
 822             csum_size) {
 823                 int extend_nr;
 824                 u64 tmp;
 825                 u32 diff;
 826                 u32 free_space;
 827
 828                 if (btrfs_leaf_free_space(fs_info, leaf) <
 829                                  sizeof(struct btrfs_item) + csum_size * 2)
 830                         goto insert;
 831
 832                 free_space = btrfs_leaf_free_space(fs_info, leaf) -
 833                                          sizeof(struct btrfs_item) - csum_size;
 834                 tmp = sums->len - total_bytes;
 835                 tmp >>= fs_info->sb->s_blocksize_bits;
 836                 WARN_ON(tmp < 1);
 837
 838                 extend_nr = max_t(int, 1, (int)tmp);
 839                 diff = (csum_offset + extend_nr) * csum_size;
 840                 diff = min(diff,
 841                            MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
 842
 843                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 844                 diff = min(free_space, diff);
 845                 diff /= csum_size;
 846                 diff *= csum_size;
 847
 848                 btrfs_extend_item(fs_info, path, diff);
 849                 ret = 0;
 850                 goto csum;
 851         }
 852
 853 insert:
 854         btrfs_release_path(path);
 855         csum_offset = 0;
 856         if (found_next) {
 857                 u64 tmp;
 858
 859                 tmp = sums->len - total_bytes;
 860                 tmp >>= fs_info->sb->s_blocksize_bits;
 861                 tmp = min(tmp, (next_offset - file_key.offset) >>
 862                                          fs_info->sb->s_blocksize_bits);
 863
 864                 tmp = max_t(u64, 1, tmp);
 865                 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
 866                 ins_size = csum_size * tmp;
 867         } else {
 868                 ins_size = csum_size;
 869         }
 870         path->leave_spinning = 1;
 871         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 872                                       ins_size);
 873         path->leave_spinning = 0;
 874         if (ret < 0)
 875                 goto fail_unlock;
 876         if (WARN_ON(ret != 0))
 877                 goto fail_unlock;
 878         leaf = path->nodes[0];
 879 csum:
 880         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 881         item_end = (struct btrfs_csum_item *)((unsigned char *)item +
 882                                       btrfs_item_size_nr(leaf, path->slots[0]));
 883         item = (struct btrfs_csum_item *)((unsigned char *)item +
 884                                           csum_offset * csum_size);
 885 found:
 886         ins_size = (u32)(sums->len - total_bytes) >>
 887                    fs_info->sb->s_blocksize_bits;
 888         ins_size *= csum_size;
 889         ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
 890                               ins_size);
 891         write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
 892                             ins_size);
 893
 894         ins_size /= csum_size;
 895         total_bytes += ins_size * fs_info->sectorsize;
 896         index += ins_size;
 897
 898         btrfs_mark_buffer_dirty(path->nodes[0]);
 899         if (total_bytes < sums->len) {
 900                 btrfs_release_path(path);
 901                 cond_resched();
 902                 goto again;
 903         }
 904 out:
 905         btrfs_free_path(path);
 906         return ret;
 907
 908 fail_unlock:
 909         goto out;
 910 }
 911
 912 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 913                                      const struct btrfs_path *path,
 914                                      struct btrfs_file_extent_item *fi,
 915                                      const bool new_inline,
 916                                      struct extent_map *em)
 917 {
 918         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 919         struct btrfs_root *root = inode->root;
 920         struct extent_buffer *leaf = path->nodes[0];
 921         const int slot = path->slots[0];
 922         struct btrfs_key key;
 923         u64 extent_start, extent_end;
 924         u64 bytenr;
 925         u8 type = btrfs_file_extent_type(leaf, fi);
 926         int compress_type = btrfs_file_extent_compression(leaf, fi);
 927
 928         em->bdev = fs_info->fs_devices->latest_bdev;
 929         btrfs_item_key_to_cpu(leaf, &key, slot);
 930         extent_start = key.offset;
 931
 932         if (type == BTRFS_FILE_EXTENT_REG ||
 933             type == BTRFS_FILE_EXTENT_PREALLOC) {
 934                 extent_end = extent_start +
 935                         btrfs_file_extent_num_bytes(leaf, fi);
 936         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 937                 size_t size;
 938                 size = btrfs_file_extent_ram_bytes(leaf, fi);
 939                 extent_end = ALIGN(extent_start + size,
 940                                    fs_info->sectorsize);
 941         }
 942
 943         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
 944         if (type == BTRFS_FILE_EXTENT_REG ||
 945             type == BTRFS_FILE_EXTENT_PREALLOC) {
 946                 em->start = extent_start;
 947                 em->len = extent_end - extent_start;
 948                 em->orig_start = extent_start -
 949                         btrfs_file_extent_offset(leaf, fi);
 950                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
 951                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 952                 if (bytenr == 0) {
 953                         em->block_start = EXTENT_MAP_HOLE;
 954                         return;
 955                 }
 956                 if (compress_type != BTRFS_COMPRESS_NONE) {
 957                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 958                         em->compress_type = compress_type;
 959                         em->block_start = bytenr;
 960                         em->block_len = em->orig_block_len;
 961                 } else {
 962                         bytenr += btrfs_file_extent_offset(leaf, fi);
 963                         em->block_start = bytenr;
 964                         em->block_len = em->len;
 965                         if (type == BTRFS_FILE_EXTENT_PREALLOC)
 966                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
 967                 }
 968         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 969                 em->block_start = EXTENT_MAP_INLINE;
 970                 em->start = extent_start;
 971                 em->len = extent_end - extent_start;
 972                 /*
 973                  * Initialize orig_start and block_len with the same values
 974                  * as in inode.c:btrfs_get_extent().
 975                  */
 976                 em->orig_start = EXTENT_MAP_HOLE;
 977                 em->block_len = (u64)-1;
 978                 if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) {
 979                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 980                         em->compress_type = compress_type;
 981                 }
 982         } else {
 983                 btrfs_err(fs_info,
 984                           "unknown file extent item type %d, inode %llu, offset %llu, "
 985                           "root %llu", type, btrfs_ino(inode), extent_start,
 986                           root->root_key.objectid);
 987         }
 988 }