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 <crypto/hash.h>
  12 #include "ctree.h"
  13 #include "disk-io.h"
  14 #include "transaction.h"
  15 #include "volumes.h"
  16 #include "print-tree.h"
  17 #include "compression.h"
  18
  19 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  20                                    sizeof(struct btrfs_item) * 2) / \
  21                                   size) - 1))
  22
  23 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  24                                        PAGE_SIZE))
  25
  26 /**
  27  * @inode - the inode we want to update the disk_i_size for
  28  * @new_i_size - the i_size we want to set to, 0 if we use i_size
  29  *
  30  * With NO_HOLES set this simply sets the disk_is_size to whatever i_size_read()
  31  * returns as it is perfectly fine with a file that has holes without hole file
  32  * extent items.
  33  *
  34  * However without NO_HOLES we need to only return the area that is contiguous
  35  * from the 0 offset of the file.  Otherwise we could end up adjust i_size up
  36  * to an extent that has a gap in between.
  37  *
  38  * Finally new_i_size should only be set in the case of truncate where we're not
  39  * ready to use i_size_read() as the limiter yet.
  40  */
  41 void btrfs_inode_safe_disk_i_size_write(struct inode *inode, u64 new_i_size)
  42 {
  43         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
  44         u64 start, end, i_size;
  45         int ret;
  46
  47         i_size = new_i_size ?: i_size_read(inode);
  48         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
  49                 BTRFS_I(inode)->disk_i_size = i_size;
  50                 return;
  51         }
  52
  53         spin_lock(&BTRFS_I(inode)->lock);
  54         ret = find_contiguous_extent_bit(&BTRFS_I(inode)->file_extent_tree, 0,
  55                                          &start, &end, EXTENT_DIRTY);
  56         if (!ret && start == 0)
  57                 i_size = min(i_size, end + 1);
  58         else
  59                 i_size = 0;
  60         BTRFS_I(inode)->disk_i_size = i_size;
  61         spin_unlock(&BTRFS_I(inode)->lock);
  62 }
  63
  64 /**
  65  * @inode - the inode we're modifying
  66  * @start - the start file offset of the file extent we've inserted
  67  * @len - the logical length of the file extent item
  68  *
  69  * Call when we are inserting a new file extent where there was none before.
  70  * Does not need to call this in the case where we're replacing an existing file
  71  * extent, however if not sure it's fine to call this multiple times.
  72  *
  73  * The start and len must match the file extent item, so thus must be sectorsize
  74  * aligned.
  75  */
  76 int btrfs_inode_set_file_extent_range(struct btrfs_inode *inode, u64 start,
  77                                       u64 len)
  78 {
  79         if (len == 0)
  80                 return 0;
  81
  82         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize));
  83
  84         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
  85                 return 0;
  86         return set_extent_bits(&inode->file_extent_tree, start, start + len - 1,
  87                                EXTENT_DIRTY);
  88 }
  89
  90 /**
  91  * @inode - the inode we're modifying
  92  * @start - the start file offset of the file extent we've inserted
  93  * @len - the logical length of the file extent item
  94  *
  95  * Called when we drop a file extent, for example when we truncate.  Doesn't
  96  * need to be called for cases where we're replacing a file extent, like when
  97  * we've COWed a file extent.
  98  *
  99  * The start and len must match the file extent item, so thus must be sectorsize
 100  * aligned.
 101  */
 102 int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
 103                                         u64 len)
 104 {
 105         if (len == 0)
 106                 return 0;
 107
 108         ASSERT(IS_ALIGNED(start + len, inode->root->fs_info->sectorsize) ||
 109                len == (u64)-1);
 110
 111         if (btrfs_fs_incompat(inode->root->fs_info, NO_HOLES))
 112                 return 0;
 113         return clear_extent_bit(&inode->file_extent_tree, start,
 114                                 start + len - 1, EXTENT_DIRTY, 0, 0, NULL);
 115 }
 116
 117 static inline u32 max_ordered_sum_bytes(struct btrfs_fs_info *fs_info,
 118                                         u16 csum_size)
 119 {
 120         u32 ncsums = (PAGE_SIZE - sizeof(struct btrfs_ordered_sum)) / csum_size;
 121
 122         return ncsums * fs_info->sectorsize;
 123 }
 124
 125 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 126                              struct btrfs_root *root,
 127                              u64 objectid, u64 pos,
 128                              u64 disk_offset, u64 disk_num_bytes,
 129                              u64 num_bytes, u64 offset, u64 ram_bytes,
 130                              u8 compression, u8 encryption, u16 other_encoding)
 131 {
 132         int ret = 0;
 133         struct btrfs_file_extent_item *item;
 134         struct btrfs_key file_key;
 135         struct btrfs_path *path;
 136         struct extent_buffer *leaf;
 137
 138         path = btrfs_alloc_path();
 139         if (!path)
 140                 return -ENOMEM;
 141         file_key.objectid = objectid;
 142         file_key.offset = pos;
 143         file_key.type = BTRFS_EXTENT_DATA_KEY;
 144
 145         path->leave_spinning = 1;
 146         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 147                                       sizeof(*item));
 148         if (ret < 0)
 149                 goto out;
 150         BUG_ON(ret); /* Can't happen */
 151         leaf = path->nodes[0];
 152         item = btrfs_item_ptr(leaf, path->slots[0],
 153                               struct btrfs_file_extent_item);
 154         btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
 155         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
 156         btrfs_set_file_extent_offset(leaf, item, offset);
 157         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
 158         btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
 159         btrfs_set_file_extent_generation(leaf, item, trans->transid);
 160         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
 161         btrfs_set_file_extent_compression(leaf, item, compression);
 162         btrfs_set_file_extent_encryption(leaf, item, encryption);
 163         btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
 164
 165         btrfs_mark_buffer_dirty(leaf);
 166 out:
 167         btrfs_free_path(path);
 168         return ret;
 169 }
 170
 171 static struct btrfs_csum_item *
 172 btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 173                   struct btrfs_root *root,
 174                   struct btrfs_path *path,
 175                   u64 bytenr, int cow)
 176 {
 177         struct btrfs_fs_info *fs_info = root->fs_info;
 178         int ret;
 179         struct btrfs_key file_key;
 180         struct btrfs_key found_key;
 181         struct btrfs_csum_item *item;
 182         struct extent_buffer *leaf;
 183         u64 csum_offset = 0;
 184         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 185         int csums_in_item;
 186
 187         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 188         file_key.offset = bytenr;
 189         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 190         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 191         if (ret < 0)
 192                 goto fail;
 193         leaf = path->nodes[0];
 194         if (ret > 0) {
 195                 ret = 1;
 196                 if (path->slots[0] == 0)
 197                         goto fail;
 198                 path->slots[0]--;
 199                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 200                 if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 201                         goto fail;
 202
 203                 csum_offset = (bytenr - found_key.offset) >>
 204                                 fs_info->sb->s_blocksize_bits;
 205                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 206                 csums_in_item /= csum_size;
 207
 208                 if (csum_offset == csums_in_item) {
 209                         ret = -EFBIG;
 210                         goto fail;
 211                 } else if (csum_offset > csums_in_item) {
 212                         goto fail;
 213                 }
 214         }
 215         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 216         item = (struct btrfs_csum_item *)((unsigned char *)item +
 217                                           csum_offset * csum_size);
 218         return item;
 219 fail:
 220         if (ret > 0)
 221                 ret = -ENOENT;
 222         return ERR_PTR(ret);
 223 }
 224
 225 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 226                              struct btrfs_root *root,
 227                              struct btrfs_path *path, u64 objectid,
 228                              u64 offset, int mod)
 229 {
 230         int ret;
 231         struct btrfs_key file_key;
 232         int ins_len = mod < 0 ? -1 : 0;
 233         int cow = mod != 0;
 234
 235         file_key.objectid = objectid;
 236         file_key.offset = offset;
 237         file_key.type = BTRFS_EXTENT_DATA_KEY;
 238         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 239         return ret;
 240 }
 241
 242 /**
 243  * btrfs_lookup_bio_sums - Look up checksums for a bio.
 244  * @inode: inode that the bio is for.
 245  * @bio: bio to look up.
 246  * @offset: Unless (u64)-1, look up checksums for this offset in the file.
 247  *          If (u64)-1, use the page offsets from the bio instead.
 248  * @dst: Buffer of size nblocks * btrfs_super_csum_size() used to return
 249  *       checksum (nblocks = bio->bi_iter.bi_size / fs_info->sectorsize). If
 250  *       NULL, the checksum buffer is allocated and returned in
 251  *       btrfs_io_bio(bio)->csum instead.
 252  *
 253  * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
 254  */
 255 blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 256                                    u64 offset, u8 *dst)
 257 {
 258         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 259         struct bio_vec bvec;
 260         struct bvec_iter iter;
 261         struct btrfs_csum_item *item = NULL;
 262         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 263         struct btrfs_path *path;
 264         const bool page_offsets = (offset == (u64)-1);
 265         u8 *csum;
 266         u64 item_start_offset = 0;
 267         u64 item_last_offset = 0;
 268         u64 disk_bytenr;
 269         u64 page_bytes_left;
 270         u32 diff;
 271         int nblocks;
 272         int count = 0;
 273         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 274
 275         path = btrfs_alloc_path();
 276         if (!path)
 277                 return BLK_STS_RESOURCE;
 278
 279         nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits;
 280         if (!dst) {
 281                 struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);
 282
 283                 if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 284                         btrfs_bio->csum = kmalloc_array(nblocks, csum_size,
 285                                                         GFP_NOFS);
 286                         if (!btrfs_bio->csum) {
 287                                 btrfs_free_path(path);
 288                                 return BLK_STS_RESOURCE;
 289                         }
 290                 } else {
 291                         btrfs_bio->csum = btrfs_bio->csum_inline;
 292                 }
 293                 csum = btrfs_bio->csum;
 294         } else {
 295                 csum = dst;
 296         }
 297
 298         if (bio->bi_iter.bi_size > PAGE_SIZE * 8)
 299                 path->reada = READA_FORWARD;
 300
 301         /*
 302          * the free space stuff is only read when it hasn't been
 303          * updated in the current transaction.  So, we can safely
 304          * read from the commit root and sidestep a nasty deadlock
 305          * between reading the free space cache and updating the csum tree.
 306          */
 307         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 308                 path->search_commit_root = 1;
 309                 path->skip_locking = 1;
 310         }
 311
 312         disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
 313
 314         bio_for_each_segment(bvec, bio, iter) {
 315                 page_bytes_left = bvec.bv_len;
 316                 if (count)
 317                         goto next;
 318
 319                 if (page_offsets)
 320                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 321                 count = btrfs_find_ordered_sum(BTRFS_I(inode), offset,
 322                                                disk_bytenr, csum, nblocks);
 323                 if (count)
 324                         goto found;
 325
 326                 if (!item || disk_bytenr < item_start_offset ||
 327                     disk_bytenr >= item_last_offset) {
 328                         struct btrfs_key found_key;
 329                         u32 item_size;
 330
 331                         if (item)
 332                                 btrfs_release_path(path);
 333                         item = btrfs_lookup_csum(NULL, fs_info->csum_root,
 334                                                  path, disk_bytenr, 0);
 335                         if (IS_ERR(item)) {
 336                                 count = 1;
 337                                 memset(csum, 0, csum_size);
 338                                 if (BTRFS_I(inode)->root->root_key.objectid ==
 339                                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 340                                         set_extent_bits(io_tree, offset,
 341                                                 offset + fs_info->sectorsize - 1,
 342                                                 EXTENT_NODATASUM);
 343                                 } else {
 344                                         btrfs_info_rl(fs_info,
 345                                                    "no csum found for inode %llu start %llu",
 346                                                btrfs_ino(BTRFS_I(inode)), offset);
 347                                 }
 348                                 item = NULL;
 349                                 btrfs_release_path(path);
 350                                 goto found;
 351                         }
 352                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 353                                               path->slots[0]);
 354
 355                         item_start_offset = found_key.offset;
 356                         item_size = btrfs_item_size_nr(path->nodes[0],
 357                                                        path->slots[0]);
 358                         item_last_offset = item_start_offset +
 359                                 (item_size / csum_size) *
 360                                 fs_info->sectorsize;
 361                         item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 362                                               struct btrfs_csum_item);
 363                 }
 364                 /*
 365                  * this byte range must be able to fit inside
 366                  * a single leaf so it will also fit inside a u32
 367                  */
 368                 diff = disk_bytenr - item_start_offset;
 369                 diff = diff / fs_info->sectorsize;
 370                 diff = diff * csum_size;
 371                 count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >>
 372                                             inode->i_sb->s_blocksize_bits);
 373                 read_extent_buffer(path->nodes[0], csum,
 374                                    ((unsigned long)item) + diff,
 375                                    csum_size * count);
 376 found:
 377                 csum += count * csum_size;
 378                 nblocks -= count;
 379 next:
 380                 while (count > 0) {
 381                         count--;
 382                         disk_bytenr += fs_info->sectorsize;
 383                         offset += fs_info->sectorsize;
 384                         page_bytes_left -= fs_info->sectorsize;
 385                         if (!page_bytes_left)
 386                                 break; /* move to next bio */
 387                 }
 388         }
 389
 390         WARN_ON_ONCE(count);
 391         btrfs_free_path(path);
 392         return BLK_STS_OK;
 393 }
 394
 395 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 396                              struct list_head *list, int search_commit)
 397 {
 398         struct btrfs_fs_info *fs_info = root->fs_info;
 399         struct btrfs_key key;
 400         struct btrfs_path *path;
 401         struct extent_buffer *leaf;
 402         struct btrfs_ordered_sum *sums;
 403         struct btrfs_csum_item *item;
 404         LIST_HEAD(tmplist);
 405         unsigned long offset;
 406         int ret;
 407         size_t size;
 408         u64 csum_end;
 409         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 410
 411         ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 412                IS_ALIGNED(end + 1, fs_info->sectorsize));
 413
 414         path = btrfs_alloc_path();
 415         if (!path)
 416                 return -ENOMEM;
 417
 418         if (search_commit) {
 419                 path->skip_locking = 1;
 420                 path->reada = READA_FORWARD;
 421                 path->search_commit_root = 1;
 422         }
 423
 424         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 425         key.offset = start;
 426         key.type = BTRFS_EXTENT_CSUM_KEY;
 427
 428         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 429         if (ret < 0)
 430                 goto fail;
 431         if (ret > 0 && path->slots[0] > 0) {
 432                 leaf = path->nodes[0];
 433                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 434                 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 435                     key.type == BTRFS_EXTENT_CSUM_KEY) {
 436                         offset = (start - key.offset) >>
 437                                  fs_info->sb->s_blocksize_bits;
 438                         if (offset * csum_size <
 439                             btrfs_item_size_nr(leaf, path->slots[0] - 1))
 440                                 path->slots[0]--;
 441                 }
 442         }
 443
 444         while (start <= end) {
 445                 leaf = path->nodes[0];
 446                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 447                         ret = btrfs_next_leaf(root, path);
 448                         if (ret < 0)
 449                                 goto fail;
 450                         if (ret > 0)
 451                                 break;
 452                         leaf = path->nodes[0];
 453                 }
 454
 455                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 456                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 457                     key.type != BTRFS_EXTENT_CSUM_KEY ||
 458                     key.offset > end)
 459                         break;
 460
 461                 if (key.offset > start)
 462                         start = key.offset;
 463
 464                 size = btrfs_item_size_nr(leaf, path->slots[0]);
 465                 csum_end = key.offset + (size / csum_size) * fs_info->sectorsize;
 466                 if (csum_end <= start) {
 467                         path->slots[0]++;
 468                         continue;
 469                 }
 470
 471                 csum_end = min(csum_end, end + 1);
 472                 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 473                                       struct btrfs_csum_item);
 474                 while (start < csum_end) {
 475                         size = min_t(size_t, csum_end - start,
 476                                      max_ordered_sum_bytes(fs_info, csum_size));
 477                         sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 478                                        GFP_NOFS);
 479                         if (!sums) {
 480                                 ret = -ENOMEM;
 481                                 goto fail;
 482                         }
 483
 484                         sums->bytenr = start;
 485                         sums->len = (int)size;
 486
 487                         offset = (start - key.offset) >>
 488                                 fs_info->sb->s_blocksize_bits;
 489                         offset *= csum_size;
 490                         size >>= fs_info->sb->s_blocksize_bits;
 491
 492                         read_extent_buffer(path->nodes[0],
 493                                            sums->sums,
 494                                            ((unsigned long)item) + offset,
 495                                            csum_size * size);
 496
 497                         start += fs_info->sectorsize * size;
 498                         list_add_tail(&sums->list, &tmplist);
 499                 }
 500                 path->slots[0]++;
 501         }
 502         ret = 0;
 503 fail:
 504         while (ret < 0 && !list_empty(&tmplist)) {
 505                 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 506                 list_del(&sums->list);
 507                 kfree(sums);
 508         }
 509         list_splice_tail(&tmplist, list);
 510
 511         btrfs_free_path(path);
 512         return ret;
 513 }
 514
 515 /*
 516  * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
 517  * @inode:       Owner of the data inside the bio
 518  * @bio:         Contains the data to be checksummed
 519  * @file_start:  offset in file this bio begins to describe
 520  * @contig:      Boolean. If true/1 means all bio vecs in this bio are
 521  *               contiguous and they begin at @file_start in the file. False/0
 522  *               means this bio can contains potentially discontigous bio vecs
 523  *               so the logical offset of each should be calculated separately.
 524  */
 525 blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 526                        u64 file_start, int contig)
 527 {
 528         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 529         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 530         struct btrfs_ordered_sum *sums;
 531         struct btrfs_ordered_extent *ordered = NULL;
 532         char *data;
 533         struct bvec_iter iter;
 534         struct bio_vec bvec;
 535         int index;
 536         int nr_sectors;
 537         unsigned long total_bytes = 0;
 538         unsigned long this_sum_bytes = 0;
 539         int i;
 540         u64 offset;
 541         unsigned nofs_flag;
 542         const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 543
 544         nofs_flag = memalloc_nofs_save();
 545         sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 546                        GFP_KERNEL);
 547         memalloc_nofs_restore(nofs_flag);
 548
 549         if (!sums)
 550                 return BLK_STS_RESOURCE;
 551
 552         sums->len = bio->bi_iter.bi_size;
 553         INIT_LIST_HEAD(&sums->list);
 554
 555         if (contig)
 556                 offset = file_start;
 557         else
 558                 offset = 0; /* shut up gcc */
 559
 560         sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;
 561         index = 0;
 562
 563         shash->tfm = fs_info->csum_shash;
 564
 565         bio_for_each_segment(bvec, bio, iter) {
 566                 if (!contig)
 567                         offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 568
 569                 if (!ordered) {
 570                         ordered = btrfs_lookup_ordered_extent(inode, offset);
 571                         /*
 572                          * The bio range is not covered by any ordered extent,
 573                          * must be a code logic error.
 574                          */
 575                         if (unlikely(!ordered)) {
 576                                 WARN(1, KERN_WARNING
 577                         "no ordered extent for root %llu ino %llu offset %llu\n",
 578                                      inode->root->root_key.objectid,
 579                                      btrfs_ino(inode), offset);
 580                                 kvfree(sums);
 581                                 return BLK_STS_IOERR;
 582                         }
 583                 }
 584
 585                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
 586                                                  bvec.bv_len + fs_info->sectorsize
 587                                                  - 1);
 588
 589                 for (i = 0; i < nr_sectors; i++) {
 590                         if (offset >= ordered->file_offset + ordered->num_bytes ||
 591                             offset < ordered->file_offset) {
 592                                 unsigned long bytes_left;
 593
 594                                 sums->len = this_sum_bytes;
 595                                 this_sum_bytes = 0;
 596                                 btrfs_add_ordered_sum(ordered, sums);
 597                                 btrfs_put_ordered_extent(ordered);
 598
 599                                 bytes_left = bio->bi_iter.bi_size - total_bytes;
 600
 601                                 nofs_flag = memalloc_nofs_save();
 602                                 sums = kvzalloc(btrfs_ordered_sum_size(fs_info,
 603                                                       bytes_left), GFP_KERNEL);
 604                                 memalloc_nofs_restore(nofs_flag);
 605                                 if (!sums)
 606                                         return BLK_STS_RESOURCE;
 607
 608                                 sums->len = bytes_left;
 609                                 ordered = btrfs_lookup_ordered_extent(inode,
 610                                                                 offset);
 611                                 ASSERT(ordered); /* Logic error */
 612                                 sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9)
 613                                         + total_bytes;
 614                                 index = 0;
 615                         }
 616
 617                         data = kmap_atomic(bvec.bv_page);
 618                         crypto_shash_digest(shash, data + bvec.bv_offset
 619                                             + (i * fs_info->sectorsize),
 620                                             fs_info->sectorsize,
 621                                             sums->sums + index);
 622                         kunmap_atomic(data);
 623                         index += csum_size;
 624                         offset += fs_info->sectorsize;
 625                         this_sum_bytes += fs_info->sectorsize;
 626                         total_bytes += fs_info->sectorsize;
 627                 }
 628
 629         }
 630         this_sum_bytes = 0;
 631         btrfs_add_ordered_sum(ordered, sums);
 632         btrfs_put_ordered_extent(ordered);
 633         return 0;
 634 }
 635
 636 /*
 637  * helper function for csum removal, this expects the
 638  * key to describe the csum pointed to by the path, and it expects
 639  * the csum to overlap the range [bytenr, len]
 640  *
 641  * The csum should not be entirely contained in the range and the
 642  * range should not be entirely contained in the csum.
 643  *
 644  * This calls btrfs_truncate_item with the correct args based on the
 645  * overlap, and fixes up the key as required.
 646  */
 647 static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 648                                        struct btrfs_path *path,
 649                                        struct btrfs_key *key,
 650                                        u64 bytenr, u64 len)
 651 {
 652         struct extent_buffer *leaf;
 653         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 654         u64 csum_end;
 655         u64 end_byte = bytenr + len;
 656         u32 blocksize_bits = fs_info->sb->s_blocksize_bits;
 657
 658         leaf = path->nodes[0];
 659         csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 660         csum_end <<= fs_info->sb->s_blocksize_bits;
 661         csum_end += key->offset;
 662
 663         if (key->offset < bytenr && csum_end <= end_byte) {
 664                 /*
 665                  *         [ bytenr - len ]
 666                  *         [   ]
 667                  *   [csum     ]
 668                  *   A simple truncate off the end of the item
 669                  */
 670                 u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 671                 new_size *= csum_size;
 672                 btrfs_truncate_item(path, new_size, 1);
 673         } else if (key->offset >= bytenr && csum_end > end_byte &&
 674                    end_byte > key->offset) {
 675                 /*
 676                  *         [ bytenr - len ]
 677                  *                 [ ]
 678                  *                 [csum     ]
 679                  * we need to truncate from the beginning of the csum
 680                  */
 681                 u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 682                 new_size *= csum_size;
 683
 684                 btrfs_truncate_item(path, new_size, 0);
 685
 686                 key->offset = end_byte;
 687                 btrfs_set_item_key_safe(fs_info, path, key);
 688         } else {
 689                 BUG();
 690         }
 691 }
 692
 693 /*
 694  * deletes the csum items from the csum tree for a given
 695  * range of bytes.
 696  */
 697 int btrfs_del_csums(struct btrfs_trans_handle *trans,
 698                     struct btrfs_root *root, u64 bytenr, u64 len)
 699 {
 700         struct btrfs_fs_info *fs_info = trans->fs_info;
 701         struct btrfs_path *path;
 702         struct btrfs_key key;
 703         u64 end_byte = bytenr + len;
 704         u64 csum_end;
 705         struct extent_buffer *leaf;
 706         int ret = 0;
 707         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 708         int blocksize_bits = fs_info->sb->s_blocksize_bits;
 709
 710         ASSERT(root == fs_info->csum_root ||
 711                root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
 712
 713         path = btrfs_alloc_path();
 714         if (!path)
 715                 return -ENOMEM;
 716
 717         while (1) {
 718                 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 719                 key.offset = end_byte - 1;
 720                 key.type = BTRFS_EXTENT_CSUM_KEY;
 721
 722                 path->leave_spinning = 1;
 723                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 724                 if (ret > 0) {
 725                         ret = 0;
 726                         if (path->slots[0] == 0)
 727                                 break;
 728                         path->slots[0]--;
 729                 } else if (ret < 0) {
 730                         break;
 731                 }
 732
 733                 leaf = path->nodes[0];
 734                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 735
 736                 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 737                     key.type != BTRFS_EXTENT_CSUM_KEY) {
 738                         break;
 739                 }
 740
 741                 if (key.offset >= end_byte)
 742                         break;
 743
 744                 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 745                 csum_end <<= blocksize_bits;
 746                 csum_end += key.offset;
 747
 748                 /* this csum ends before we start, we're done */
 749                 if (csum_end <= bytenr)
 750                         break;
 751
 752                 /* delete the entire item, it is inside our range */
 753                 if (key.offset >= bytenr && csum_end <= end_byte) {
 754                         int del_nr = 1;
 755
 756                         /*
 757                          * Check how many csum items preceding this one in this
 758                          * leaf correspond to our range and then delete them all
 759                          * at once.
 760                          */
 761                         if (key.offset > bytenr && path->slots[0] > 0) {
 762                                 int slot = path->slots[0] - 1;
 763
 764                                 while (slot >= 0) {
 765                                         struct btrfs_key pk;
 766
 767                                         btrfs_item_key_to_cpu(leaf, &pk, slot);
 768                                         if (pk.offset < bytenr ||
 769                                             pk.type != BTRFS_EXTENT_CSUM_KEY ||
 770                                             pk.objectid !=
 771                                             BTRFS_EXTENT_CSUM_OBJECTID)
 772                                                 break;
 773                                         path->slots[0] = slot;
 774                                         del_nr++;
 775                                         key.offset = pk.offset;
 776                                         slot--;
 777                                 }
 778                         }
 779                         ret = btrfs_del_items(trans, root, path,
 780                                               path->slots[0], del_nr);
 781                         if (ret)
 782                                 break;
 783                         if (key.offset == bytenr)
 784                                 break;
 785                 } else if (key.offset < bytenr && csum_end > end_byte) {
 786                         unsigned long offset;
 787                         unsigned long shift_len;
 788                         unsigned long item_offset;
 789                         /*
 790                          *        [ bytenr - len ]
 791                          *     [csum                ]
 792                          *
 793                          * Our bytes are in the middle of the csum,
 794                          * we need to split this item and insert a new one.
 795                          *
 796                          * But we can't drop the path because the
 797                          * csum could change, get removed, extended etc.
 798                          *
 799                          * The trick here is the max size of a csum item leaves
 800                          * enough room in the tree block for a single
 801                          * item header.  So, we split the item in place,
 802                          * adding a new header pointing to the existing
 803                          * bytes.  Then we loop around again and we have
 804                          * a nicely formed csum item that we can neatly
 805                          * truncate.
 806                          */
 807                         offset = (bytenr - key.offset) >> blocksize_bits;
 808                         offset *= csum_size;
 809
 810                         shift_len = (len >> blocksize_bits) * csum_size;
 811
 812                         item_offset = btrfs_item_ptr_offset(leaf,
 813                                                             path->slots[0]);
 814
 815                         memzero_extent_buffer(leaf, item_offset + offset,
 816                                              shift_len);
 817                         key.offset = bytenr;
 818
 819                         /*
 820                          * btrfs_split_item returns -EAGAIN when the
 821                          * item changed size or key
 822                          */
 823                         ret = btrfs_split_item(trans, root, path, &key, offset);
 824                         if (ret && ret != -EAGAIN) {
 825                                 btrfs_abort_transaction(trans, ret);
 826                                 break;
 827                         }
 828                         ret = 0;
 829
 830                         key.offset = end_byte - 1;
 831                 } else {
 832                         truncate_one_csum(fs_info, path, &key, bytenr, len);
 833                         if (key.offset < bytenr)
 834                                 break;
 835                 }
 836                 btrfs_release_path(path);
 837         }
 838         btrfs_free_path(path);
 839         return ret;
 840 }
 841
 842 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 843                            struct btrfs_root *root,
 844                            struct btrfs_ordered_sum *sums)
 845 {
 846         struct btrfs_fs_info *fs_info = root->fs_info;
 847         struct btrfs_key file_key;
 848         struct btrfs_key found_key;
 849         struct btrfs_path *path;
 850         struct btrfs_csum_item *item;
 851         struct btrfs_csum_item *item_end;
 852         struct extent_buffer *leaf = NULL;
 853         u64 next_offset;
 854         u64 total_bytes = 0;
 855         u64 csum_offset;
 856         u64 bytenr;
 857         u32 nritems;
 858         u32 ins_size;
 859         int index = 0;
 860         int found_next;
 861         int ret;
 862         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 863
 864         path = btrfs_alloc_path();
 865         if (!path)
 866                 return -ENOMEM;
 867 again:
 868         next_offset = (u64)-1;
 869         found_next = 0;
 870         bytenr = sums->bytenr + total_bytes;
 871         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 872         file_key.offset = bytenr;
 873         file_key.type = BTRFS_EXTENT_CSUM_KEY;
 874
 875         item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 876         if (!IS_ERR(item)) {
 877                 ret = 0;
 878                 leaf = path->nodes[0];
 879                 item_end = btrfs_item_ptr(leaf, path->slots[0],
 880                                           struct btrfs_csum_item);
 881                 item_end = (struct btrfs_csum_item *)((char *)item_end +
 882                            btrfs_item_size_nr(leaf, path->slots[0]));
 883                 goto found;
 884         }
 885         ret = PTR_ERR(item);
 886         if (ret != -EFBIG && ret != -ENOENT)
 887                 goto out;
 888
 889         if (ret == -EFBIG) {
 890                 u32 item_size;
 891                 /* we found one, but it isn't big enough yet */
 892                 leaf = path->nodes[0];
 893                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 894                 if ((item_size / csum_size) >=
 895                     MAX_CSUM_ITEMS(fs_info, csum_size)) {
 896                         /* already at max size, make a new one */
 897                         goto insert;
 898                 }
 899         } else {
 900                 int slot = path->slots[0] + 1;
 901                 /* we didn't find a csum item, insert one */
 902                 nritems = btrfs_header_nritems(path->nodes[0]);
 903                 if (!nritems || (path->slots[0] >= nritems - 1)) {
 904                         ret = btrfs_next_leaf(root, path);
 905                         if (ret < 0) {
 906                                 goto out;
 907                         } else if (ret > 0) {
 908                                 found_next = 1;
 909                                 goto insert;
 910                         }
 911                         slot = path->slots[0];
 912                 }
 913                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 914                 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 915                     found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 916                         found_next = 1;
 917                         goto insert;
 918                 }
 919                 next_offset = found_key.offset;
 920                 found_next = 1;
 921                 goto insert;
 922         }
 923
 924         /*
 925          * At this point, we know the tree has a checksum item that ends at an
 926          * offset matching the start of the checksum range we want to insert.
 927          * We try to extend that item as much as possible and then add as many
 928          * checksums to it as they fit.
 929          *
 930          * First check if the leaf has enough free space for at least one
 931          * checksum. If it has go directly to the item extension code, otherwise
 932          * release the path and do a search for insertion before the extension.
 933          */
 934         if (btrfs_leaf_free_space(leaf) >= csum_size) {
 935                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 936                 csum_offset = (bytenr - found_key.offset) >>
 937                         fs_info->sb->s_blocksize_bits;
 938                 goto extend_csum;
 939         }
 940
 941         btrfs_release_path(path);
 942         ret = btrfs_search_slot(trans, root, &file_key, path,
 943                                 csum_size, 1);
 944         if (ret < 0)
 945                 goto out;
 946
 947         if (ret > 0) {
 948                 if (path->slots[0] == 0)
 949                         goto insert;
 950                 path->slots[0]--;
 951         }
 952
 953         leaf = path->nodes[0];
 954         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 955         csum_offset = (bytenr - found_key.offset) >>
 956                         fs_info->sb->s_blocksize_bits;
 957
 958         if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 959             found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 960             csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
 961                 goto insert;
 962         }
 963
 964 extend_csum:
 965         if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
 966             csum_size) {
 967                 int extend_nr;
 968                 u64 tmp;
 969                 u32 diff;
 970
 971                 tmp = sums->len - total_bytes;
 972                 tmp >>= fs_info->sb->s_blocksize_bits;
 973                 WARN_ON(tmp < 1);
 974
 975                 extend_nr = max_t(int, 1, (int)tmp);
 976                 diff = (csum_offset + extend_nr) * csum_size;
 977                 diff = min(diff,
 978                            MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
 979
 980                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 981                 diff = min_t(u32, btrfs_leaf_free_space(leaf), diff);
 982                 diff /= csum_size;
 983                 diff *= csum_size;
 984
 985                 btrfs_extend_item(path, diff);
 986                 ret = 0;
 987                 goto csum;
 988         }
 989
 990 insert:
 991         btrfs_release_path(path);
 992         csum_offset = 0;
 993         if (found_next) {
 994                 u64 tmp;
 995
 996                 tmp = sums->len - total_bytes;
 997                 tmp >>= fs_info->sb->s_blocksize_bits;
 998                 tmp = min(tmp, (next_offset - file_key.offset) >>
 999                                          fs_info->sb->s_blocksize_bits);
1000
1001                 tmp = max_t(u64, 1, tmp);
1002                 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
1003                 ins_size = csum_size * tmp;
1004         } else {
1005                 ins_size = csum_size;
1006         }
1007         path->leave_spinning = 1;
1008         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
1009                                       ins_size);
1010         path->leave_spinning = 0;
1011         if (ret < 0)
1012                 goto out;
1013         if (WARN_ON(ret != 0))
1014                 goto out;
1015         leaf = path->nodes[0];
1016 csum:
1017         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
1018         item_end = (struct btrfs_csum_item *)((unsigned char *)item +
1019                                       btrfs_item_size_nr(leaf, path->slots[0]));
1020         item = (struct btrfs_csum_item *)((unsigned char *)item +
1021                                           csum_offset * csum_size);
1022 found:
1023         ins_size = (u32)(sums->len - total_bytes) >>
1024                    fs_info->sb->s_blocksize_bits;
1025         ins_size *= csum_size;
1026         ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
1027                               ins_size);
1028         write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
1029                             ins_size);
1030
1031         index += ins_size;
1032         ins_size /= csum_size;
1033         total_bytes += ins_size * fs_info->sectorsize;
1034
1035         btrfs_mark_buffer_dirty(path->nodes[0]);
1036         if (total_bytes < sums->len) {
1037                 btrfs_release_path(path);
1038                 cond_resched();
1039                 goto again;
1040         }
1041 out:
1042         btrfs_free_path(path);
1043         return ret;
1044 }
1045
1046 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
1047                                      const struct btrfs_path *path,
1048                                      struct btrfs_file_extent_item *fi,
1049                                      const bool new_inline,
1050                                      struct extent_map *em)
1051 {
1052         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1053         struct btrfs_root *root = inode->root;
1054         struct extent_buffer *leaf = path->nodes[0];
1055         const int slot = path->slots[0];
1056         struct btrfs_key key;
1057         u64 extent_start, extent_end;
1058         u64 bytenr;
1059         u8 type = btrfs_file_extent_type(leaf, fi);
1060         int compress_type = btrfs_file_extent_compression(leaf, fi);
1061
1062         btrfs_item_key_to_cpu(leaf, &key, slot);
1063         extent_start = key.offset;
1064         extent_end = btrfs_file_extent_end(path);
1065         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1066         if (type == BTRFS_FILE_EXTENT_REG ||
1067             type == BTRFS_FILE_EXTENT_PREALLOC) {
1068                 em->start = extent_start;
1069                 em->len = extent_end - extent_start;
1070                 em->orig_start = extent_start -
1071                         btrfs_file_extent_offset(leaf, fi);
1072                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
1073                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1074                 if (bytenr == 0) {
1075                         em->block_start = EXTENT_MAP_HOLE;
1076                         return;
1077                 }
1078                 if (compress_type != BTRFS_COMPRESS_NONE) {
1079                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
1080                         em->compress_type = compress_type;
1081                         em->block_start = bytenr;
1082                         em->block_len = em->orig_block_len;
1083                 } else {
1084                         bytenr += btrfs_file_extent_offset(leaf, fi);
1085                         em->block_start = bytenr;
1086                         em->block_len = em->len;
1087                         if (type == BTRFS_FILE_EXTENT_PREALLOC)
1088                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
1089                 }
1090         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1091                 em->block_start = EXTENT_MAP_INLINE;
1092                 em->start = extent_start;
1093                 em->len = extent_end - extent_start;
1094                 /*
1095                  * Initialize orig_start and block_len with the same values
1096                  * as in inode.c:btrfs_get_extent().
1097                  */
1098                 em->orig_start = EXTENT_MAP_HOLE;
1099                 em->block_len = (u64)-1;
1100                 if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) {
1101                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
1102                         em->compress_type = compress_type;
1103                 }
1104         } else {
1105                 btrfs_err(fs_info,
1106                           "unknown file extent item type %d, inode %llu, offset %llu, "
1107                           "root %llu", type, btrfs_ino(inode), extent_start,
1108                           root->root_key.objectid);
1109         }
1110 }
1111
1112 /*
1113  * Returns the end offset (non inclusive) of the file extent item the given path
1114  * points to. If it points to an inline extent, the returned offset is rounded
1115  * up to the sector size.
1116  */
1117 u64 btrfs_file_extent_end(const struct btrfs_path *path)
1118 {
1119         const struct extent_buffer *leaf = path->nodes[0];
1120         const int slot = path->slots[0];
1121         struct btrfs_file_extent_item *fi;
1122         struct btrfs_key key;
1123         u64 end;
1124
1125         btrfs_item_key_to_cpu(leaf, &key, slot);
1126         ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
1127         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1128
1129         if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
1130                 end = btrfs_file_extent_ram_bytes(leaf, fi);
1131                 end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
1132         } else {
1133                 end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1134         }
1135
1136         return end;
1137 }