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 <linux/sched/mm.h>
  11 #include "ctree.h"
  12 #include "disk-io.h"
  13 #include "transaction.h"
  14 #include "volumes.h"
  15 #include "print-tree.h"
  16 #include "compression.h"
  17
  18 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  19                                    sizeof(struct btrfs_item) * 2) / \
  20                                   size) - 1))
  21
  22 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  23                                        PAGE_SIZE))
  24
  25 #define MAX_ORDERED_SUM_BYTES(fs_info) ((PAGE_SIZE - \
  26                                    sizeof(struct btrfs_ordered_sum)) / \
  27                                    sizeof(u32) * (fs_info)->sectorsize)
  28
  29 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  30                              struct btrfs_root *root,
  31                              u64 objectid, u64 pos,
  32                              u64 disk_offset, u64 disk_num_bytes,
  33                              u64 num_bytes, u64 offset, u64 ram_bytes,
  34                              u8 compression, u8 encryption, u16 other_encoding)
  35 {
  36         int ret = 0;
  37         struct btrfs_file_extent_item *item;
  38         struct btrfs_key file_key;
  39         struct btrfs_path *path;
  40         struct extent_buffer *leaf;
  41
  42         path = btrfs_alloc_path();
  43         if (!path)
  44                 return -ENOMEM;
  45         file_key.objectid = objectid;
  46         file_key.offset = pos;
  47         file_key.type = BTRFS_EXTENT_DATA_KEY;
  48
  49         path->leave_spinning = 1;
  50         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  51                                       sizeof(*item));
  52         if (ret < 0)
  53                 goto out;
  54         BUG_ON(ret); /* Can't happen */
  55         leaf = path->nodes[0];
  56         item = btrfs_item_ptr(leaf, path->slots[0],
  57                               struct btrfs_file_extent_item);
  58         btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
  59         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  60         btrfs_set_file_extent_offset(leaf, item, offset);
  61         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  62         btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
  63         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  64         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  65         btrfs_set_file_extent_compression(leaf, item, compression);
  66         btrfs_set_file_extent_encryption(leaf, item, encryption);
  67         btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
  68
  69         btrfs_mark_buffer_dirty(leaf);
  70 out:
  71         btrfs_free_path(path);
  72         return ret;
  73 }
  74
  75 static struct btrfs_csum_item *
  76 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  77                   struct btrfs_root *root,
  78                   struct btrfs_path *path,
  79                   u64 bytenr, int cow)
  80 {
  81         struct btrfs_fs_info *fs_info = root->fs_info;
  82         int ret;
  83         struct btrfs_key file_key;
  84         struct btrfs_key found_key;
  85         struct btrfs_csum_item *item;
  86         struct extent_buffer *leaf;
  87         u64 csum_offset = 0;
  88         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
  89         int csums_in_item;
  90
  91         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
  92         file_key.offset = bytenr;
  93         file_key.type = BTRFS_EXTENT_CSUM_KEY;
  94         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
  95         if (ret < 0)
  96                 goto fail;
  97         leaf = path->nodes[0];
  98         if (ret > 0) {
  99                 ret = 1;
 100                 if (path->slots[0] == 0)
 101                         goto fail;
 102                 path->slots[0]--;
 103                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 104                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 105                         goto fail;
 106
 107                 csum_offset = (bytenr - found_key.offset) >>
 108                                 fs_info->sb->s_blocksize_bits;
 109                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 110                 csums_in_item /= csum_size;
 111
 112                 if (csum_offset == csums_in_item) {
 113                         ret = -EFBIG;
 114                         goto fail;
 115                 } else if (csum_offset > csums_in_item) {
 116                         goto fail;
 117                 }
 118         }
 119         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 120         item = (struct btrfs_csum_item *)((unsigned char *)item +
 121                                           csum_offset * csum_size);
 122         return item;
 123 fail:
 124         if (ret > 0)
 125                 ret = -ENOENT;
 126         return ERR_PTR(ret);
 127 }
 128
 129 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 130                              struct btrfs_root *root,
 131                              struct btrfs_path *path, u64 objectid,
 132                              u64 offset, int mod)
 133 {
 134         int ret;
 135         struct btrfs_key file_key;
 136         int ins_len = mod < 0 ? -1 : 0;
 137         int cow = mod != 0;
 138
 139         file_key.objectid = objectid;
 140         file_key.offset = offset;
 141         file_key.type = BTRFS_EXTENT_DATA_KEY;
 142         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 143         return ret;
 144 }
 145
 146 static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 147                                    u64 logical_offset, u32 *dst, int dio)
 148 {
 149         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 150         struct bio_vec bvec;
 151         struct bvec_iter iter;
 152         struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);
 153         struct btrfs_csum_item *item = NULL;
 154         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 155         struct btrfs_path *path;
 156         u8 *csum;
 157         u64 offset = 0;
 158         u64 item_start_offset = 0;
 159         u64 item_last_offset = 0;
 160         u64 disk_bytenr;
 161         u64 page_bytes_left;
 162         u32 diff;
 163         int nblocks;
 164         int count = 0;
 165         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 166
 167         path = btrfs_alloc_path();
 168         if (!path)
 169                 return BLK_STS_RESOURCE;
 170
 171         nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits;
 172         if (!dst) {
 173                 if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 174                         btrfs_bio->csum = kmalloc_array(nblocks, csum_size,
 175                                                         GFP_NOFS);
 176                         if (!btrfs_bio->csum) {
 177                                 btrfs_free_path(path);
 178                                 return BLK_STS_RESOURCE;
 179                         }
 180                 } else {
 181                         btrfs_bio->csum = btrfs_bio->csum_inline;
 182                 }
 183                 csum = btrfs_bio->csum;
 184         } else {
 185                 csum = (u8 *)dst;
 186         }
 187
 188         if (bio->bi_iter.bi_size > PAGE_SIZE * 8)
 189                 path->reada = READA_FORWARD;
 190
 191         /*
 192          * the free space stuff is only read when it hasn't been
 193          * updated in the current transaction.  So, we can safely
 194          * read from the commit root and sidestep a nasty deadlock
 195          * between reading the free space cache and updating the csum tree.
 196          */
 197         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 198                 path->search_commit_root = 1;
 199                 path->skip_locking = 1;
 200         }
 201
 202         disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
 203         if (dio)
 204                 offset = logical_offset;
 205
 206         bio_for_each_segment(bvec, bio, iter) {
 207                 page_bytes_left = bvec.bv_len;
 208                 if (count)
 209                         goto next;
 210
 211                 if (!dio)
 212                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 213                 count = btrfs_find_ordered_sum(inode, offset, disk_bytenr,
 214                                                (u32 *)csum, nblocks);
 215                 if (count)
 216                         goto found;
 217
 218                 if (!item || disk_bytenr < item_start_offset ||
 219                     disk_bytenr >= item_last_offset) {
 220                         struct btrfs_key found_key;
 221                         u32 item_size;
 222
 223                         if (item)
 224                                 btrfs_release_path(path);
 225                         item = btrfs_lookup_csum(NULL, fs_info->csum_root,
 226                                                  path, disk_bytenr, 0);
 227                         if (IS_ERR(item)) {
 228                                 count = 1;
 229                                 memset(csum, 0, csum_size);
 230                                 if (BTRFS_I(inode)->root->root_key.objectid ==
 231                                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 232                                         set_extent_bits(io_tree, offset,
 233                                                 offset + fs_info->sectorsize - 1,
 234                                                 EXTENT_NODATASUM);
 235                                 } else {
 236                                         btrfs_info_rl(fs_info,
 237                                                    "no csum found for inode %llu start %llu",
 238                                                btrfs_ino(BTRFS_I(inode)), offset);
 239                                 }
 240                                 item = NULL;
 241                                 btrfs_release_path(path);
 242                                 goto found;
 243                         }
 244                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 245                                               path->slots[0]);
 246
 247                         item_start_offset = found_key.offset;
 248                         item_size = btrfs_item_size_nr(path->nodes[0],
 249                                                        path->slots[0]);
 250                         item_last_offset = item_start_offset +
 251                                 (item_size / csum_size) *
 252                                 fs_info->sectorsize;
 253                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 254                                               struct btrfs_csum_item);
 255                 }
 256                 /*
 257                  * this byte range must be able to fit inside
 258                  * a single leaf so it will also fit inside a u32
 259                  */
 260                 diff = disk_bytenr - item_start_offset;
 261                 diff = diff / fs_info->sectorsize;
 262                 diff = diff * csum_size;
 263                 count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >>
 264                                             inode->i_sb->s_blocksize_bits);
 265                 read_extent_buffer(path->nodes[0], csum,
 266                                    ((unsigned long)item) + diff,
 267                                    csum_size * count);
 268 found:
 269                 csum += count * csum_size;
 270                 nblocks -= count;
 271 next:
 272                 while (count--) {
 273                         disk_bytenr += fs_info->sectorsize;
 274                         offset += fs_info->sectorsize;
 275                         page_bytes_left -= fs_info->sectorsize;
 276                         if (!page_bytes_left)
 277                                 break; /* move to next bio */
 278                 }
 279         }
 280
 281         WARN_ON_ONCE(count);
 282         btrfs_free_path(path);
 283         return 0;
 284 }
 285
 286 blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u32 *dst)
 287 {
 288         return __btrfs_lookup_bio_sums(inode, bio, 0, dst, 0);
 289 }
 290
 291 blk_status_t btrfs_lookup_bio_sums_dio(struct inode *inode, struct bio *bio, u64 offset)
 292 {
 293         return __btrfs_lookup_bio_sums(inode, bio, offset, NULL, 1);
 294 }
 295
 296 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 297                              struct list_head *list, int search_commit)
 298 {
 299         struct btrfs_fs_info *fs_info = root->fs_info;
 300         struct btrfs_key key;
 301         struct btrfs_path *path;
 302         struct extent_buffer *leaf;
 303         struct btrfs_ordered_sum *sums;
 304         struct btrfs_csum_item *item;
 305         LIST_HEAD(tmplist);
 306         unsigned long offset;
 307         int ret;
 308         size_t size;
 309         u64 csum_end;
 310         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 311
 312         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 313                IS_ALIGNED(end + 1, fs_info->sectorsize));
 314
 315         path = btrfs_alloc_path();
 316         if (!path)
 317                 return -ENOMEM;
 318
 319         if (search_commit) {
 320                 path->skip_locking = 1;
 321                 path->reada = READA_FORWARD;
 322                 path->search_commit_root = 1;
 323         }
 324
 325         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 326         key.offset = start;
 327         key.type = BTRFS_EXTENT_CSUM_KEY;
 328
 329         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 330         if (ret < 0)
 331                 goto fail;
 332         if (ret > 0 && path->slots[0] > 0) {
 333                 leaf = path->nodes[0];
 334                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 335                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 336                     key.type == BTRFS_EXTENT_CSUM_KEY) {
 337                         offset = (start - key.offset) >>
 338                                  fs_info->sb->s_blocksize_bits;
 339                         if (offset * csum_size <
 340                             btrfs_item_size_nr(leaf, path->slots[0] - 1))
 341                                 path->slots[0]--;
 342                 }
 343         }
 344
 345         while (start <= end) {
 346                 leaf = path->nodes[0];
 347                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 348                         ret = btrfs_next_leaf(root, path);
 349                         if (ret < 0)
 350                                 goto fail;
 351                         if (ret > 0)
 352                                 break;
 353                         leaf = path->nodes[0];
 354                 }
 355
 356                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 357                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 358                     key.type != BTRFS_EXTENT_CSUM_KEY ||
 359                     key.offset > end)
 360                         break;
 361
 362                 if (key.offset > start)
 363                         start = key.offset;
 364
 365                 size = btrfs_item_size_nr(leaf, path->slots[0]);
 366                 csum_end = key.offset + (size / csum_size) * fs_info->sectorsize;
 367                 if (csum_end <= start) {
 368                         path->slots[0]++;
 369                         continue;
 370                 }
 371
 372                 csum_end = min(csum_end, end + 1);
 373                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 374                                       struct btrfs_csum_item);
 375                 while (start < csum_end) {
 376                         size = min_t(size_t, csum_end - start,
 377                                      MAX_ORDERED_SUM_BYTES(fs_info));
 378                         sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 379                                        GFP_NOFS);
 380                         if (!sums) {
 381                                 ret = -ENOMEM;
 382                                 goto fail;
 383                         }
 384
 385                         sums->bytenr = start;
 386                         sums->len = (int)size;
 387
 388                         offset = (start - key.offset) >>
 389                                 fs_info->sb->s_blocksize_bits;
 390                         offset *= csum_size;
 391                         size >>= fs_info->sb->s_blocksize_bits;
 392
 393                         read_extent_buffer(path->nodes[0],
 394                                            sums->sums,
 395                                            ((unsigned long)item) + offset,
 396                                            csum_size * size);
 397
 398                         start += fs_info->sectorsize * size;
 399                         list_add_tail(&sums->list, &tmplist);
 400                 }
 401                 path->slots[0]++;
 402         }
 403         ret = 0;
 404 fail:
 405         while (ret < 0 && !list_empty(&tmplist)) {
 406                 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 407                 list_del(&sums->list);
 408                 kfree(sums);
 409         }
 410         list_splice_tail(&tmplist, list);
 411
 412         btrfs_free_path(path);
 413         return ret;
 414 }
 415
 416 /*
 417  * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
 418  * @inode:       Owner of the data inside the bio
 419  * @bio:         Contains the data to be checksummed
 420  * @file_start:  offset in file this bio begins to describe
 421  * @contig:      Boolean. If true/1 means all bio vecs in this bio are
 422  *               contiguous and they begin at @file_start in the file. False/0
 423  *               means this bio can contains potentially discontigous bio vecs
 424  *               so the logical offset of each should be calculated separately.
 425  */
 426 blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio,
 427                        u64 file_start, int contig)
 428 {
 429         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 430         struct btrfs_ordered_sum *sums;
 431         struct btrfs_ordered_extent *ordered = NULL;
 432         char *data;
 433         struct bvec_iter iter;
 434         struct bio_vec bvec;
 435         int index;
 436         int nr_sectors;
 437         unsigned long total_bytes = 0;
 438         unsigned long this_sum_bytes = 0;
 439         int i;
 440         u64 offset;
 441         unsigned nofs_flag;
 442
 443         nofs_flag = memalloc_nofs_save();
 444         sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 445                        GFP_KERNEL);
 446         memalloc_nofs_restore(nofs_flag);
 447
 448         if (!sums)
 449                 return BLK_STS_RESOURCE;
 450
 451         sums->len = bio->bi_iter.bi_size;
 452         INIT_LIST_HEAD(&sums->list);
 453
 454         if (contig)
 455                 offset = file_start;
 456         else
 457                 offset = 0; /* shut up gcc */
 458
 459         sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;
 460         index = 0;
 461
 462         bio_for_each_segment(bvec, bio, iter) {
 463                 if (!contig)
 464                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 465
 466                 if (!ordered) {
 467                         ordered = btrfs_lookup_ordered_extent(inode, offset);
 468                         BUG_ON(!ordered); /* Logic error */
 469                 }
 470
 471                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
 472                                                  bvec.bv_len + fs_info->sectorsize
 473                                                  - 1);
 474
 475                 for (i = 0; i < nr_sectors; i++) {
 476                         if (offset >= ordered->file_offset + ordered->len ||
 477                                 offset < ordered->file_offset) {
 478                                 unsigned long bytes_left;
 479
 480                                 sums->len = this_sum_bytes;
 481                                 this_sum_bytes = 0;
 482                                 btrfs_add_ordered_sum(ordered, sums);
 483                                 btrfs_put_ordered_extent(ordered);
 484
 485                                 bytes_left = bio->bi_iter.bi_size - total_bytes;
 486
 487                                 nofs_flag = memalloc_nofs_save();
 488                                 sums = kvzalloc(btrfs_ordered_sum_size(fs_info,
 489                                                       bytes_left), GFP_KERNEL);
 490                                 memalloc_nofs_restore(nofs_flag);
 491                                 BUG_ON(!sums); /* -ENOMEM */
 492                                 sums->len = bytes_left;
 493                                 ordered = btrfs_lookup_ordered_extent(inode,
 494                                                                 offset);
 495                                 ASSERT(ordered); /* Logic error */
 496                                 sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9)
 497                                         + total_bytes;
 498                                 index = 0;
 499                         }
 500
 501                         sums->sums[index] = ~(u32)0;
 502                         data = kmap_atomic(bvec.bv_page);
 503                         sums->sums[index]
 504                                 = btrfs_csum_data(data + bvec.bv_offset
 505                                                 + (i * fs_info->sectorsize),
 506                                                 sums->sums[index],
 507                                                 fs_info->sectorsize);
 508                         kunmap_atomic(data);
 509                         btrfs_csum_final(sums->sums[index],
 510                                         (char *)(sums->sums + index));
 511                         index++;
 512                         offset += fs_info->sectorsize;
 513                         this_sum_bytes += fs_info->sectorsize;
 514                         total_bytes += fs_info->sectorsize;
 515                 }
 516
 517         }
 518         this_sum_bytes = 0;
 519         btrfs_add_ordered_sum(ordered, sums);
 520         btrfs_put_ordered_extent(ordered);
 521         return 0;
 522 }
 523
 524 /*
 525  * helper function for csum removal, this expects the
 526  * key to describe the csum pointed to by the path, and it expects
 527  * the csum to overlap the range [bytenr, len]
 528  *
 529  * The csum should not be entirely contained in the range and the
 530  * range should not be entirely contained in the csum.
 531  *
 532  * This calls btrfs_truncate_item with the correct args based on the
 533  * overlap, and fixes up the key as required.
 534  */
 535 static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 536                                        struct btrfs_path *path,
 537                                        struct btrfs_key *key,
 538                                        u64 bytenr, u64 len)
 539 {
 540         struct extent_buffer *leaf;
 541         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 542         u64 csum_end;
 543         u64 end_byte = bytenr + len;
 544         u32 blocksize_bits = fs_info->sb->s_blocksize_bits;
 545
 546         leaf = path->nodes[0];
 547         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 548         csum_end <<= fs_info->sb->s_blocksize_bits;
 549         csum_end += key->offset;
 550
 551         if (key->offset < bytenr && csum_end <= end_byte) {
 552                 /*
 553                  *         [ bytenr - len ]
 554                  *         [   ]
 555                  *   [csum     ]
 556                  *   A simple truncate off the end of the item
 557                  */
 558                 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 559                 new_size *= csum_size;
 560                 btrfs_truncate_item(path, new_size, 1);
 561         } else if (key->offset >= bytenr && csum_end > end_byte &&
 562                    end_byte > key->offset) {
 563                 /*
 564                  *         [ bytenr - len ]
 565                  *                 [ ]
 566                  *                 [csum     ]
 567                  * we need to truncate from the beginning of the csum
 568                  */
 569                 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 570                 new_size *= csum_size;
 571
 572                 btrfs_truncate_item(path, new_size, 0);
 573
 574                 key->offset = end_byte;
 575                 btrfs_set_item_key_safe(fs_info, path, key);
 576         } else {
 577                 BUG();
 578         }
 579 }
 580
 581 /*
 582  * deletes the csum items from the csum tree for a given
 583  * range of bytes.
 584  */
 585 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 586                     struct btrfs_fs_info *fs_info, u64 bytenr, u64 len)
 587 {
 588         struct btrfs_root *root = fs_info->csum_root;
 589         struct btrfs_path *path;
 590         struct btrfs_key key;
 591         u64 end_byte = bytenr + len;
 592         u64 csum_end;
 593         struct extent_buffer *leaf;
 594         int ret;
 595         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 596         int blocksize_bits = fs_info->sb->s_blocksize_bits;
 597
 598         path = btrfs_alloc_path();
 599         if (!path)
 600                 return -ENOMEM;
 601
 602         while (1) {
 603                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 604                 key.offset = end_byte - 1;
 605                 key.type = BTRFS_EXTENT_CSUM_KEY;
 606
 607                 path->leave_spinning = 1;
 608                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 609                 if (ret > 0) {
 610                         if (path->slots[0] == 0)
 611                                 break;
 612                         path->slots[0]--;
 613                 } else if (ret < 0) {
 614                         break;
 615                 }
 616
 617                 leaf = path->nodes[0];
 618                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 619
 620                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 621                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 622                         break;
 623                 }
 624
 625                 if (key.offset >= end_byte)
 626                         break;
 627
 628                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 629                 csum_end <<= blocksize_bits;
 630                 csum_end += key.offset;
 631
 632                 /* this csum ends before we start, we're done */
 633                 if (csum_end <= bytenr)
 634                         break;
 635
 636                 /* delete the entire item, it is inside our range */
 637                 if (key.offset >= bytenr && csum_end <= end_byte) {
 638                         int del_nr = 1;
 639
 640                         /*
 641                          * Check how many csum items preceding this one in this
 642                          * leaf correspond to our range and then delete them all
 643                          * at once.
 644                          */
 645                         if (key.offset > bytenr && path->slots[0] > 0) {
 646                                 int slot = path->slots[0] - 1;
 647
 648                                 while (slot >= 0) {
 649                                         struct btrfs_key pk;
 650
 651                                         btrfs_item_key_to_cpu(leaf, &pk, slot);
 652                                         if (pk.offset < bytenr ||
 653                                             pk.type != BTRFS_EXTENT_CSUM_KEY ||
 654                                             pk.objectid !=
 655                                             BTRFS_EXTENT_CSUM_OBJECTID)
 656                                                 break;
 657                                         path->slots[0] = slot;
 658                                         del_nr++;
 659                                         key.offset = pk.offset;
 660                                         slot--;
 661                                 }
 662                         }
 663                         ret = btrfs_del_items(trans, root, path,
 664                                               path->slots[0], del_nr);
 665                         if (ret)
 666                                 goto out;
 667                         if (key.offset == bytenr)
 668                                 break;
 669                 } else if (key.offset < bytenr && csum_end > end_byte) {
 670                         unsigned long offset;
 671                         unsigned long shift_len;
 672                         unsigned long item_offset;
 673                         /*
 674                          *        [ bytenr - len ]
 675                          *     [csum                ]
 676                          *
 677                          * Our bytes are in the middle of the csum,
 678                          * we need to split this item and insert a new one.
 679                          *
 680                          * But we can't drop the path because the
 681                          * csum could change, get removed, extended etc.
 682                          *
 683                          * The trick here is the max size of a csum item leaves
 684                          * enough room in the tree block for a single
 685                          * item header.  So, we split the item in place,
 686                          * adding a new header pointing to the existing
 687                          * bytes.  Then we loop around again and we have
 688                          * a nicely formed csum item that we can neatly
 689                          * truncate.
 690                          */
 691                         offset = (bytenr - key.offset) >> blocksize_bits;
 692                         offset *= csum_size;
 693
 694                         shift_len = (len >> blocksize_bits) * csum_size;
 695
 696                         item_offset = btrfs_item_ptr_offset(leaf,
 697                                                             path->slots[0]);
 698
 699                         memzero_extent_buffer(leaf, item_offset + offset,
 700                                              shift_len);
 701                         key.offset = bytenr;
 702
 703                         /*
 704                          * btrfs_split_item returns -EAGAIN when the
 705                          * item changed size or key
 706                          */
 707                         ret = btrfs_split_item(trans, root, path, &key, offset);
 708                         if (ret && ret != -EAGAIN) {
 709                                 btrfs_abort_transaction(trans, ret);
 710                                 goto out;
 711                         }
 712
 713                         key.offset = end_byte - 1;
 714                 } else {
 715                         truncate_one_csum(fs_info, path, &key, bytenr, len);
 716                         if (key.offset < bytenr)
 717                                 break;
 718                 }
 719                 btrfs_release_path(path);
 720         }
 721         ret = 0;
 722 out:
 723         btrfs_free_path(path);
 724         return ret;
 725 }
 726
 727 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 728                            struct btrfs_root *root,
 729                            struct btrfs_ordered_sum *sums)
 730 {
 731         struct btrfs_fs_info *fs_info = root->fs_info;
 732         struct btrfs_key file_key;
 733         struct btrfs_key found_key;
 734         struct btrfs_path *path;
 735         struct btrfs_csum_item *item;
 736         struct btrfs_csum_item *item_end;
 737         struct extent_buffer *leaf = NULL;
 738         u64 next_offset;
 739         u64 total_bytes = 0;
 740         u64 csum_offset;
 741         u64 bytenr;
 742         u32 nritems;
 743         u32 ins_size;
 744         int index = 0;
 745         int found_next;
 746         int ret;
 747         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 748
 749         path = btrfs_alloc_path();
 750         if (!path)
 751                 return -ENOMEM;
 752 again:
 753         next_offset = (u64)-1;
 754         found_next = 0;
 755         bytenr = sums->bytenr + total_bytes;
 756         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 757         file_key.offset = bytenr;
 758         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 759
 760         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 761         if (!IS_ERR(item)) {
 762                 ret = 0;
 763                 leaf = path->nodes[0];
 764                 item_end = btrfs_item_ptr(leaf, path->slots[0],
 765                                           struct btrfs_csum_item);
 766                 item_end = (struct btrfs_csum_item *)((char *)item_end +
 767                            btrfs_item_size_nr(leaf, path->slots[0]));
 768                 goto found;
 769         }
 770         ret = PTR_ERR(item);
 771         if (ret != -EFBIG && ret != -ENOENT)
 772                 goto fail_unlock;
 773
 774         if (ret == -EFBIG) {
 775                 u32 item_size;
 776                 /* we found one, but it isn't big enough yet */
 777                 leaf = path->nodes[0];
 778                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 779                 if ((item_size / csum_size) >=
 780                     MAX_CSUM_ITEMS(fs_info, csum_size)) {
 781                         /* already at max size, make a new one */
 782                         goto insert;
 783                 }
 784         } else {
 785                 int slot = path->slots[0] + 1;
 786                 /* we didn't find a csum item, insert one */
 787                 nritems = btrfs_header_nritems(path->nodes[0]);
 788                 if (!nritems || (path->slots[0] >= nritems - 1)) {
 789                         ret = btrfs_next_leaf(root, path);
 790                         if (ret == 1)
 791                                 found_next = 1;
 792                         if (ret != 0)
 793                                 goto insert;
 794                         slot = path->slots[0];
 795                 }
 796                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 797                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 798                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 799                         found_next = 1;
 800                         goto insert;
 801                 }
 802                 next_offset = found_key.offset;
 803                 found_next = 1;
 804                 goto insert;
 805         }
 806
 807         /*
 808          * at this point, we know the tree has an item, but it isn't big
 809          * enough yet to put our csum in.  Grow it
 810          */
 811         btrfs_release_path(path);
 812         ret = btrfs_search_slot(trans, root, &file_key, path,
 813                                 csum_size, 1);
 814         if (ret < 0)
 815                 goto fail_unlock;
 816
 817         if (ret > 0) {
 818                 if (path->slots[0] == 0)
 819                         goto insert;
 820                 path->slots[0]--;
 821         }
 822
 823         leaf = path->nodes[0];
 824         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 825         csum_offset = (bytenr - found_key.offset) >>
 826                         fs_info->sb->s_blocksize_bits;
 827
 828         if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 829             found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 830             csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
 831                 goto insert;
 832         }
 833
 834         if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
 835             csum_size) {
 836                 int extend_nr;
 837                 u64 tmp;
 838                 u32 diff;
 839                 u32 free_space;
 840
 841                 if (btrfs_leaf_free_space(leaf) <
 842                                  sizeof(struct btrfs_item) + csum_size * 2)
 843                         goto insert;
 844
 845                 free_space = btrfs_leaf_free_space(leaf) -
 846                                          sizeof(struct btrfs_item) - csum_size;
 847                 tmp = sums->len - total_bytes;
 848                 tmp >>= fs_info->sb->s_blocksize_bits;
 849                 WARN_ON(tmp < 1);
 850
 851                 extend_nr = max_t(int, 1, (int)tmp);
 852                 diff = (csum_offset + extend_nr) * csum_size;
 853                 diff = min(diff,
 854                            MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
 855
 856                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 857                 diff = min(free_space, diff);
 858                 diff /= csum_size;
 859                 diff *= csum_size;
 860
 861                 btrfs_extend_item(path, diff);
 862                 ret = 0;
 863                 goto csum;
 864         }
 865
 866 insert:
 867         btrfs_release_path(path);
 868         csum_offset = 0;
 869         if (found_next) {
 870                 u64 tmp;
 871
 872                 tmp = sums->len - total_bytes;
 873                 tmp >>= fs_info->sb->s_blocksize_bits;
 874                 tmp = min(tmp, (next_offset - file_key.offset) >>
 875                                          fs_info->sb->s_blocksize_bits);
 876
 877                 tmp = max_t(u64, 1, tmp);
 878                 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
 879                 ins_size = csum_size * tmp;
 880         } else {
 881                 ins_size = csum_size;
 882         }
 883         path->leave_spinning = 1;
 884         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 885                                       ins_size);
 886         path->leave_spinning = 0;
 887         if (ret < 0)
 888                 goto fail_unlock;
 889         if (WARN_ON(ret != 0))
 890                 goto fail_unlock;
 891         leaf = path->nodes[0];
 892 csum:
 893         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 894         item_end = (struct btrfs_csum_item *)((unsigned char *)item +
 895                                       btrfs_item_size_nr(leaf, path->slots[0]));
 896         item = (struct btrfs_csum_item *)((unsigned char *)item +
 897                                           csum_offset * csum_size);
 898 found:
 899         ins_size = (u32)(sums->len - total_bytes) >>
 900                    fs_info->sb->s_blocksize_bits;
 901         ins_size *= csum_size;
 902         ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
 903                               ins_size);
 904         write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
 905                             ins_size);
 906
 907         ins_size /= csum_size;
 908         total_bytes += ins_size * fs_info->sectorsize;
 909         index += ins_size;
 910
 911         btrfs_mark_buffer_dirty(path->nodes[0]);
 912         if (total_bytes < sums->len) {
 913                 btrfs_release_path(path);
 914                 cond_resched();
 915                 goto again;
 916         }
 917 out:
 918         btrfs_free_path(path);
 919         return ret;
 920
 921 fail_unlock:
 922         goto out;
 923 }
 924
 925 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 926                                      const struct btrfs_path *path,
 927                                      struct btrfs_file_extent_item *fi,
 928                                      const bool new_inline,
 929                                      struct extent_map *em)
 930 {
 931         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 932         struct btrfs_root *root = inode->root;
 933         struct extent_buffer *leaf = path->nodes[0];
 934         const int slot = path->slots[0];
 935         struct btrfs_key key;
 936         u64 extent_start, extent_end;
 937         u64 bytenr;
 938         u8 type = btrfs_file_extent_type(leaf, fi);
 939         int compress_type = btrfs_file_extent_compression(leaf, fi);
 940
 941         em->bdev = fs_info->fs_devices->latest_bdev;
 942         btrfs_item_key_to_cpu(leaf, &key, slot);
 943         extent_start = key.offset;
 944
 945         if (type == BTRFS_FILE_EXTENT_REG ||
 946             type == BTRFS_FILE_EXTENT_PREALLOC) {
 947                 extent_end = extent_start +
 948                         btrfs_file_extent_num_bytes(leaf, fi);
 949         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 950                 size_t size;
 951                 size = btrfs_file_extent_ram_bytes(leaf, fi);
 952                 extent_end = ALIGN(extent_start + size,
 953                                    fs_info->sectorsize);
 954         }
 955
 956         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
 957         if (type == BTRFS_FILE_EXTENT_REG ||
 958             type == BTRFS_FILE_EXTENT_PREALLOC) {
 959                 em->start = extent_start;
 960                 em->len = extent_end - extent_start;
 961                 em->orig_start = extent_start -
 962                         btrfs_file_extent_offset(leaf, fi);
 963                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
 964                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 965                 if (bytenr == 0) {
 966                         em->block_start = EXTENT_MAP_HOLE;
 967                         return;
 968                 }
 969                 if (compress_type != BTRFS_COMPRESS_NONE) {
 970                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 971                         em->compress_type = compress_type;
 972                         em->block_start = bytenr;
 973                         em->block_len = em->orig_block_len;
 974                 } else {
 975                         bytenr += btrfs_file_extent_offset(leaf, fi);
 976                         em->block_start = bytenr;
 977                         em->block_len = em->len;
 978                         if (type == BTRFS_FILE_EXTENT_PREALLOC)
 979                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
 980                 }
 981         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 982                 em->block_start = EXTENT_MAP_INLINE;
 983                 em->start = extent_start;
 984                 em->len = extent_end - extent_start;
 985                 /*
 986                  * Initialize orig_start and block_len with the same values
 987                  * as in inode.c:btrfs_get_extent().
 988                  */
 989                 em->orig_start = EXTENT_MAP_HOLE;
 990                 em->block_len = (u64)-1;
 991                 if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) {
 992                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 993                         em->compress_type = compress_type;
 994                 }
 995         } else {
 996                 btrfs_err(fs_info,
 997                           "unknown file extent item type %d, inode %llu, offset %llu, "
 998                           "root %llu", type, btrfs_ino(inode), extent_start,
 999                           root->root_key.objectid);
1000         }
1001 }