linux/fs/btrfs/file-item.c
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   1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/bio.h>
  20#include <linux/slab.h>
  21#include <linux/pagemap.h>
  22#include <linux/highmem.h>
  23#include "ctree.h"
  24#include "disk-io.h"
  25#include "transaction.h"
  26#include "volumes.h"
  27#include "print-tree.h"
  28#include "compression.h"
  29
  30#define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \
  31                                   sizeof(struct btrfs_item) * 2) / \
  32                                  size) - 1))
  33
  34#define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \
  35                                       PAGE_SIZE))
  36
  37#define MAX_ORDERED_SUM_BYTES(fs_info) ((PAGE_SIZE - \
  38                                   sizeof(struct btrfs_ordered_sum)) / \
  39                                   sizeof(u32) * (fs_info)->sectorsize)
  40
  41int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  42                             struct btrfs_root *root,
  43                             u64 objectid, u64 pos,
  44                             u64 disk_offset, u64 disk_num_bytes,
  45                             u64 num_bytes, u64 offset, u64 ram_bytes,
  46                             u8 compression, u8 encryption, u16 other_encoding)
  47{
  48        int ret = 0;
  49        struct btrfs_file_extent_item *item;
  50        struct btrfs_key file_key;
  51        struct btrfs_path *path;
  52        struct extent_buffer *leaf;
  53
  54        path = btrfs_alloc_path();
  55        if (!path)
  56                return -ENOMEM;
  57        file_key.objectid = objectid;
  58        file_key.offset = pos;
  59        file_key.type = BTRFS_EXTENT_DATA_KEY;
  60
  61        path->leave_spinning = 1;
  62        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  63                                      sizeof(*item));
  64        if (ret < 0)
  65                goto out;
  66        BUG_ON(ret); /* Can't happen */
  67        leaf = path->nodes[0];
  68        item = btrfs_item_ptr(leaf, path->slots[0],
  69                              struct btrfs_file_extent_item);
  70        btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
  71        btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  72        btrfs_set_file_extent_offset(leaf, item, offset);
  73        btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  74        btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes);
  75        btrfs_set_file_extent_generation(leaf, item, trans->transid);
  76        btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  77        btrfs_set_file_extent_compression(leaf, item, compression);
  78        btrfs_set_file_extent_encryption(leaf, item, encryption);
  79        btrfs_set_file_extent_other_encoding(leaf, item, other_encoding);
  80
  81        btrfs_mark_buffer_dirty(leaf);
  82out:
  83        btrfs_free_path(path);
  84        return ret;
  85}
  86
  87static struct btrfs_csum_item *
  88btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  89                  struct btrfs_root *root,
  90                  struct btrfs_path *path,
  91                  u64 bytenr, int cow)
  92{
  93        struct btrfs_fs_info *fs_info = root->fs_info;
  94        int ret;
  95        struct btrfs_key file_key;
  96        struct btrfs_key found_key;
  97        struct btrfs_csum_item *item;
  98        struct extent_buffer *leaf;
  99        u64 csum_offset = 0;
 100        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 101        int csums_in_item;
 102
 103        file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 104        file_key.offset = bytenr;
 105        file_key.type = BTRFS_EXTENT_CSUM_KEY;
 106        ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
 107        if (ret < 0)
 108                goto fail;
 109        leaf = path->nodes[0];
 110        if (ret > 0) {
 111                ret = 1;
 112                if (path->slots[0] == 0)
 113                        goto fail;
 114                path->slots[0]--;
 115                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 116                if (found_key.type != BTRFS_EXTENT_CSUM_KEY)
 117                        goto fail;
 118
 119                csum_offset = (bytenr - found_key.offset) >>
 120                                fs_info->sb->s_blocksize_bits;
 121                csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 122                csums_in_item /= csum_size;
 123
 124                if (csum_offset == csums_in_item) {
 125                        ret = -EFBIG;
 126                        goto fail;
 127                } else if (csum_offset > csums_in_item) {
 128                        goto fail;
 129                }
 130        }
 131        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 132        item = (struct btrfs_csum_item *)((unsigned char *)item +
 133                                          csum_offset * csum_size);
 134        return item;
 135fail:
 136        if (ret > 0)
 137                ret = -ENOENT;
 138        return ERR_PTR(ret);
 139}
 140
 141int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 142                             struct btrfs_root *root,
 143                             struct btrfs_path *path, u64 objectid,
 144                             u64 offset, int mod)
 145{
 146        int ret;
 147        struct btrfs_key file_key;
 148        int ins_len = mod < 0 ? -1 : 0;
 149        int cow = mod != 0;
 150
 151        file_key.objectid = objectid;
 152        file_key.offset = offset;
 153        file_key.type = BTRFS_EXTENT_DATA_KEY;
 154        ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 155        return ret;
 156}
 157
 158static void btrfs_io_bio_endio_readpage(struct btrfs_io_bio *bio, int err)
 159{
 160        kfree(bio->csum_allocated);
 161}
 162
 163static int __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
 164                                   u64 logical_offset, u32 *dst, int dio)
 165{
 166        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 167        struct bio_vec *bvec;
 168        struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio);
 169        struct btrfs_csum_item *item = NULL;
 170        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 171        struct btrfs_path *path;
 172        u8 *csum;
 173        u64 offset = 0;
 174        u64 item_start_offset = 0;
 175        u64 item_last_offset = 0;
 176        u64 disk_bytenr;
 177        u64 page_bytes_left;
 178        u32 diff;
 179        int nblocks;
 180        int count = 0, i;
 181        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 182
 183        path = btrfs_alloc_path();
 184        if (!path)
 185                return -ENOMEM;
 186
 187        nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits;
 188        if (!dst) {
 189                if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
 190                        btrfs_bio->csum_allocated = kmalloc_array(nblocks,
 191                                        csum_size, GFP_NOFS);
 192                        if (!btrfs_bio->csum_allocated) {
 193                                btrfs_free_path(path);
 194                                return -ENOMEM;
 195                        }
 196                        btrfs_bio->csum = btrfs_bio->csum_allocated;
 197                        btrfs_bio->end_io = btrfs_io_bio_endio_readpage;
 198                } else {
 199                        btrfs_bio->csum = btrfs_bio->csum_inline;
 200                }
 201                csum = btrfs_bio->csum;
 202        } else {
 203                csum = (u8 *)dst;
 204        }
 205
 206        if (bio->bi_iter.bi_size > PAGE_SIZE * 8)
 207                path->reada = READA_FORWARD;
 208
 209        WARN_ON(bio->bi_vcnt <= 0);
 210
 211        /*
 212         * the free space stuff is only read when it hasn't been
 213         * updated in the current transaction.  So, we can safely
 214         * read from the commit root and sidestep a nasty deadlock
 215         * between reading the free space cache and updating the csum tree.
 216         */
 217        if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 218                path->search_commit_root = 1;
 219                path->skip_locking = 1;
 220        }
 221
 222        disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;
 223        if (dio)
 224                offset = logical_offset;
 225
 226        bio_for_each_segment_all(bvec, bio, i) {
 227                page_bytes_left = bvec->bv_len;
 228                if (count)
 229                        goto next;
 230
 231                if (!dio)
 232                        offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 233                count = btrfs_find_ordered_sum(inode, offset, disk_bytenr,
 234                                               (u32 *)csum, nblocks);
 235                if (count)
 236                        goto found;
 237
 238                if (!item || disk_bytenr < item_start_offset ||
 239                    disk_bytenr >= item_last_offset) {
 240                        struct btrfs_key found_key;
 241                        u32 item_size;
 242
 243                        if (item)
 244                                btrfs_release_path(path);
 245                        item = btrfs_lookup_csum(NULL, fs_info->csum_root,
 246                                                 path, disk_bytenr, 0);
 247                        if (IS_ERR(item)) {
 248                                count = 1;
 249                                memset(csum, 0, csum_size);
 250                                if (BTRFS_I(inode)->root->root_key.objectid ==
 251                                    BTRFS_DATA_RELOC_TREE_OBJECTID) {
 252                                        set_extent_bits(io_tree, offset,
 253                                                offset + fs_info->sectorsize - 1,
 254                                                EXTENT_NODATASUM);
 255                                } else {
 256                                        btrfs_info_rl(fs_info,
 257                                                   "no csum found for inode %llu start %llu",
 258                                               btrfs_ino(BTRFS_I(inode)), offset);
 259                                }
 260                                item = NULL;
 261                                btrfs_release_path(path);
 262                                goto found;
 263                        }
 264                        btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 265                                              path->slots[0]);
 266
 267                        item_start_offset = found_key.offset;
 268                        item_size = btrfs_item_size_nr(path->nodes[0],
 269                                                       path->slots[0]);
 270                        item_last_offset = item_start_offset +
 271                                (item_size / csum_size) *
 272                                fs_info->sectorsize;
 273                        item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 274                                              struct btrfs_csum_item);
 275                }
 276                /*
 277                 * this byte range must be able to fit inside
 278                 * a single leaf so it will also fit inside a u32
 279                 */
 280                diff = disk_bytenr - item_start_offset;
 281                diff = diff / fs_info->sectorsize;
 282                diff = diff * csum_size;
 283                count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >>
 284                                            inode->i_sb->s_blocksize_bits);
 285                read_extent_buffer(path->nodes[0], csum,
 286                                   ((unsigned long)item) + diff,
 287                                   csum_size * count);
 288found:
 289                csum += count * csum_size;
 290                nblocks -= count;
 291next:
 292                while (count--) {
 293                        disk_bytenr += fs_info->sectorsize;
 294                        offset += fs_info->sectorsize;
 295                        page_bytes_left -= fs_info->sectorsize;
 296                        if (!page_bytes_left)
 297                                break; /* move to next bio */
 298                }
 299        }
 300
 301        WARN_ON_ONCE(count);
 302        btrfs_free_path(path);
 303        return 0;
 304}
 305
 306int btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u32 *dst)
 307{
 308        return __btrfs_lookup_bio_sums(inode, bio, 0, dst, 0);
 309}
 310
 311int btrfs_lookup_bio_sums_dio(struct inode *inode, struct bio *bio, u64 offset)
 312{
 313        return __btrfs_lookup_bio_sums(inode, bio, offset, NULL, 1);
 314}
 315
 316int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 317                             struct list_head *list, int search_commit)
 318{
 319        struct btrfs_fs_info *fs_info = root->fs_info;
 320        struct btrfs_key key;
 321        struct btrfs_path *path;
 322        struct extent_buffer *leaf;
 323        struct btrfs_ordered_sum *sums;
 324        struct btrfs_csum_item *item;
 325        LIST_HEAD(tmplist);
 326        unsigned long offset;
 327        int ret;
 328        size_t size;
 329        u64 csum_end;
 330        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 331
 332        ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 333               IS_ALIGNED(end + 1, fs_info->sectorsize));
 334
 335        path = btrfs_alloc_path();
 336        if (!path)
 337                return -ENOMEM;
 338
 339        if (search_commit) {
 340                path->skip_locking = 1;
 341                path->reada = READA_FORWARD;
 342                path->search_commit_root = 1;
 343        }
 344
 345        key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 346        key.offset = start;
 347        key.type = BTRFS_EXTENT_CSUM_KEY;
 348
 349        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 350        if (ret < 0)
 351                goto fail;
 352        if (ret > 0 && path->slots[0] > 0) {
 353                leaf = path->nodes[0];
 354                btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 355                if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
 356                    key.type == BTRFS_EXTENT_CSUM_KEY) {
 357                        offset = (start - key.offset) >>
 358                                 fs_info->sb->s_blocksize_bits;
 359                        if (offset * csum_size <
 360                            btrfs_item_size_nr(leaf, path->slots[0] - 1))
 361                                path->slots[0]--;
 362                }
 363        }
 364
 365        while (start <= end) {
 366                leaf = path->nodes[0];
 367                if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 368                        ret = btrfs_next_leaf(root, path);
 369                        if (ret < 0)
 370                                goto fail;
 371                        if (ret > 0)
 372                                break;
 373                        leaf = path->nodes[0];
 374                }
 375
 376                btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 377                if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 378                    key.type != BTRFS_EXTENT_CSUM_KEY ||
 379                    key.offset > end)
 380                        break;
 381
 382                if (key.offset > start)
 383                        start = key.offset;
 384
 385                size = btrfs_item_size_nr(leaf, path->slots[0]);
 386                csum_end = key.offset + (size / csum_size) * fs_info->sectorsize;
 387                if (csum_end <= start) {
 388                        path->slots[0]++;
 389                        continue;
 390                }
 391
 392                csum_end = min(csum_end, end + 1);
 393                item = btrfs_item_ptr(path->nodes[0], path->slots[0],
 394                                      struct btrfs_csum_item);
 395                while (start < csum_end) {
 396                        size = min_t(size_t, csum_end - start,
 397                                     MAX_ORDERED_SUM_BYTES(fs_info));
 398                        sums = kzalloc(btrfs_ordered_sum_size(fs_info, size),
 399                                       GFP_NOFS);
 400                        if (!sums) {
 401                                ret = -ENOMEM;
 402                                goto fail;
 403                        }
 404
 405                        sums->bytenr = start;
 406                        sums->len = (int)size;
 407
 408                        offset = (start - key.offset) >>
 409                                fs_info->sb->s_blocksize_bits;
 410                        offset *= csum_size;
 411                        size >>= fs_info->sb->s_blocksize_bits;
 412
 413                        read_extent_buffer(path->nodes[0],
 414                                           sums->sums,
 415                                           ((unsigned long)item) + offset,
 416                                           csum_size * size);
 417
 418                        start += fs_info->sectorsize * size;
 419                        list_add_tail(&sums->list, &tmplist);
 420                }
 421                path->slots[0]++;
 422        }
 423        ret = 0;
 424fail:
 425        while (ret < 0 && !list_empty(&tmplist)) {
 426                sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 427                list_del(&sums->list);
 428                kfree(sums);
 429        }
 430        list_splice_tail(&tmplist, list);
 431
 432        btrfs_free_path(path);
 433        return ret;
 434}
 435
 436int btrfs_csum_one_bio(struct inode *inode, struct bio *bio,
 437                       u64 file_start, int contig)
 438{
 439        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 440        struct btrfs_ordered_sum *sums;
 441        struct btrfs_ordered_extent *ordered = NULL;
 442        char *data;
 443        struct bio_vec *bvec;
 444        int index;
 445        int nr_sectors;
 446        int i, j;
 447        unsigned long total_bytes = 0;
 448        unsigned long this_sum_bytes = 0;
 449        u64 offset;
 450
 451        WARN_ON(bio->bi_vcnt <= 0);
 452        sums = kzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size),
 453                       GFP_NOFS);
 454        if (!sums)
 455                return -ENOMEM;
 456
 457        sums->len = bio->bi_iter.bi_size;
 458        INIT_LIST_HEAD(&sums->list);
 459
 460        if (contig)
 461                offset = file_start;
 462        else
 463                offset = 0; /* shut up gcc */
 464
 465        sums->bytenr = (u64)bio->bi_iter.bi_sector << 9;
 466        index = 0;
 467
 468        bio_for_each_segment_all(bvec, bio, j) {
 469                if (!contig)
 470                        offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 471
 472                if (!ordered) {
 473                        ordered = btrfs_lookup_ordered_extent(inode, offset);
 474                        BUG_ON(!ordered); /* Logic error */
 475                }
 476
 477                data = kmap_atomic(bvec->bv_page);
 478
 479                nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
 480                                                 bvec->bv_len + fs_info->sectorsize
 481                                                 - 1);
 482
 483                for (i = 0; i < nr_sectors; i++) {
 484                        if (offset >= ordered->file_offset + ordered->len ||
 485                                offset < ordered->file_offset) {
 486                                unsigned long bytes_left;
 487
 488                                kunmap_atomic(data);
 489                                sums->len = this_sum_bytes;
 490                                this_sum_bytes = 0;
 491                                btrfs_add_ordered_sum(inode, ordered, sums);
 492                                btrfs_put_ordered_extent(ordered);
 493
 494                                bytes_left = bio->bi_iter.bi_size - total_bytes;
 495
 496                                sums = kzalloc(btrfs_ordered_sum_size(fs_info, bytes_left),
 497                                               GFP_NOFS);
 498                                BUG_ON(!sums); /* -ENOMEM */
 499                                sums->len = bytes_left;
 500                                ordered = btrfs_lookup_ordered_extent(inode,
 501                                                                offset);
 502                                ASSERT(ordered); /* Logic error */
 503                                sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9)
 504                                        + total_bytes;
 505                                index = 0;
 506
 507                                data = kmap_atomic(bvec->bv_page);
 508                        }
 509
 510                        sums->sums[index] = ~(u32)0;
 511                        sums->sums[index]
 512                                = btrfs_csum_data(data + bvec->bv_offset
 513                                                + (i * fs_info->sectorsize),
 514                                                sums->sums[index],
 515                                                fs_info->sectorsize);
 516                        btrfs_csum_final(sums->sums[index],
 517                                        (char *)(sums->sums + index));
 518                        index++;
 519                        offset += fs_info->sectorsize;
 520                        this_sum_bytes += fs_info->sectorsize;
 521                        total_bytes += fs_info->sectorsize;
 522                }
 523
 524                kunmap_atomic(data);
 525        }
 526        this_sum_bytes = 0;
 527        btrfs_add_ordered_sum(inode, ordered, sums);
 528        btrfs_put_ordered_extent(ordered);
 529        return 0;
 530}
 531
 532/*
 533 * helper function for csum removal, this expects the
 534 * key to describe the csum pointed to by the path, and it expects
 535 * the csum to overlap the range [bytenr, len]
 536 *
 537 * The csum should not be entirely contained in the range and the
 538 * range should not be entirely contained in the csum.
 539 *
 540 * This calls btrfs_truncate_item with the correct args based on the
 541 * overlap, and fixes up the key as required.
 542 */
 543static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 544                                       struct btrfs_path *path,
 545                                       struct btrfs_key *key,
 546                                       u64 bytenr, u64 len)
 547{
 548        struct extent_buffer *leaf;
 549        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 550        u64 csum_end;
 551        u64 end_byte = bytenr + len;
 552        u32 blocksize_bits = fs_info->sb->s_blocksize_bits;
 553
 554        leaf = path->nodes[0];
 555        csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 556        csum_end <<= fs_info->sb->s_blocksize_bits;
 557        csum_end += key->offset;
 558
 559        if (key->offset < bytenr && csum_end <= end_byte) {
 560                /*
 561                 *         [ bytenr - len ]
 562                 *         [   ]
 563                 *   [csum     ]
 564                 *   A simple truncate off the end of the item
 565                 */
 566                u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 567                new_size *= csum_size;
 568                btrfs_truncate_item(fs_info, path, new_size, 1);
 569        } else if (key->offset >= bytenr && csum_end > end_byte &&
 570                   end_byte > key->offset) {
 571                /*
 572                 *         [ bytenr - len ]
 573                 *                 [ ]
 574                 *                 [csum     ]
 575                 * we need to truncate from the beginning of the csum
 576                 */
 577                u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 578                new_size *= csum_size;
 579
 580                btrfs_truncate_item(fs_info, path, new_size, 0);
 581
 582                key->offset = end_byte;
 583                btrfs_set_item_key_safe(fs_info, path, key);
 584        } else {
 585                BUG();
 586        }
 587}
 588
 589/*
 590 * deletes the csum items from the csum tree for a given
 591 * range of bytes.
 592 */
 593int btrfs_del_csums(struct btrfs_trans_handle *trans,
 594                    struct btrfs_fs_info *fs_info, u64 bytenr, u64 len)
 595{
 596        struct btrfs_root *root = fs_info->csum_root;
 597        struct btrfs_path *path;
 598        struct btrfs_key key;
 599        u64 end_byte = bytenr + len;
 600        u64 csum_end;
 601        struct extent_buffer *leaf;
 602        int ret;
 603        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 604        int blocksize_bits = fs_info->sb->s_blocksize_bits;
 605
 606        path = btrfs_alloc_path();
 607        if (!path)
 608                return -ENOMEM;
 609
 610        while (1) {
 611                key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 612                key.offset = end_byte - 1;
 613                key.type = BTRFS_EXTENT_CSUM_KEY;
 614
 615                path->leave_spinning = 1;
 616                ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 617                if (ret > 0) {
 618                        if (path->slots[0] == 0)
 619                                break;
 620                        path->slots[0]--;
 621                } else if (ret < 0) {
 622                        break;
 623                }
 624
 625                leaf = path->nodes[0];
 626                btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 627
 628                if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 629                    key.type != BTRFS_EXTENT_CSUM_KEY) {
 630                        break;
 631                }
 632
 633                if (key.offset >= end_byte)
 634                        break;
 635
 636                csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size;
 637                csum_end <<= blocksize_bits;
 638                csum_end += key.offset;
 639
 640                /* this csum ends before we start, we're done */
 641                if (csum_end <= bytenr)
 642                        break;
 643
 644                /* delete the entire item, it is inside our range */
 645                if (key.offset >= bytenr && csum_end <= end_byte) {
 646                        int del_nr = 1;
 647
 648                        /*
 649                         * Check how many csum items preceding this one in this
 650                         * leaf correspond to our range and then delete them all
 651                         * at once.
 652                         */
 653                        if (key.offset > bytenr && path->slots[0] > 0) {
 654                                int slot = path->slots[0] - 1;
 655
 656                                while (slot >= 0) {
 657                                        struct btrfs_key pk;
 658
 659                                        btrfs_item_key_to_cpu(leaf, &pk, slot);
 660                                        if (pk.offset < bytenr ||
 661                                            pk.type != BTRFS_EXTENT_CSUM_KEY ||
 662                                            pk.objectid !=
 663                                            BTRFS_EXTENT_CSUM_OBJECTID)
 664                                                break;
 665                                        path->slots[0] = slot;
 666                                        del_nr++;
 667                                        key.offset = pk.offset;
 668                                        slot--;
 669                                }
 670                        }
 671                        ret = btrfs_del_items(trans, root, path,
 672                                              path->slots[0], del_nr);
 673                        if (ret)
 674                                goto out;
 675                        if (key.offset == bytenr)
 676                                break;
 677                } else if (key.offset < bytenr && csum_end > end_byte) {
 678                        unsigned long offset;
 679                        unsigned long shift_len;
 680                        unsigned long item_offset;
 681                        /*
 682                         *        [ bytenr - len ]
 683                         *     [csum                ]
 684                         *
 685                         * Our bytes are in the middle of the csum,
 686                         * we need to split this item and insert a new one.
 687                         *
 688                         * But we can't drop the path because the
 689                         * csum could change, get removed, extended etc.
 690                         *
 691                         * The trick here is the max size of a csum item leaves
 692                         * enough room in the tree block for a single
 693                         * item header.  So, we split the item in place,
 694                         * adding a new header pointing to the existing
 695                         * bytes.  Then we loop around again and we have
 696                         * a nicely formed csum item that we can neatly
 697                         * truncate.
 698                         */
 699                        offset = (bytenr - key.offset) >> blocksize_bits;
 700                        offset *= csum_size;
 701
 702                        shift_len = (len >> blocksize_bits) * csum_size;
 703
 704                        item_offset = btrfs_item_ptr_offset(leaf,
 705                                                            path->slots[0]);
 706
 707                        memzero_extent_buffer(leaf, item_offset + offset,
 708                                             shift_len);
 709                        key.offset = bytenr;
 710
 711                        /*
 712                         * btrfs_split_item returns -EAGAIN when the
 713                         * item changed size or key
 714                         */
 715                        ret = btrfs_split_item(trans, root, path, &key, offset);
 716                        if (ret && ret != -EAGAIN) {
 717                                btrfs_abort_transaction(trans, ret);
 718                                goto out;
 719                        }
 720
 721                        key.offset = end_byte - 1;
 722                } else {
 723                        truncate_one_csum(fs_info, path, &key, bytenr, len);
 724                        if (key.offset < bytenr)
 725                                break;
 726                }
 727                btrfs_release_path(path);
 728        }
 729        ret = 0;
 730out:
 731        btrfs_free_path(path);
 732        return ret;
 733}
 734
 735int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 736                           struct btrfs_root *root,
 737                           struct btrfs_ordered_sum *sums)
 738{
 739        struct btrfs_fs_info *fs_info = root->fs_info;
 740        struct btrfs_key file_key;
 741        struct btrfs_key found_key;
 742        struct btrfs_path *path;
 743        struct btrfs_csum_item *item;
 744        struct btrfs_csum_item *item_end;
 745        struct extent_buffer *leaf = NULL;
 746        u64 next_offset;
 747        u64 total_bytes = 0;
 748        u64 csum_offset;
 749        u64 bytenr;
 750        u32 nritems;
 751        u32 ins_size;
 752        int index = 0;
 753        int found_next;
 754        int ret;
 755        u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 756
 757        path = btrfs_alloc_path();
 758        if (!path)
 759                return -ENOMEM;
 760again:
 761        next_offset = (u64)-1;
 762        found_next = 0;
 763        bytenr = sums->bytenr + total_bytes;
 764        file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
 765        file_key.offset = bytenr;
 766        file_key.type = BTRFS_EXTENT_CSUM_KEY;
 767
 768        item = btrfs_lookup_csum(trans, root, path, bytenr, 1);
 769        if (!IS_ERR(item)) {
 770                ret = 0;
 771                leaf = path->nodes[0];
 772                item_end = btrfs_item_ptr(leaf, path->slots[0],
 773                                          struct btrfs_csum_item);
 774                item_end = (struct btrfs_csum_item *)((char *)item_end +
 775                           btrfs_item_size_nr(leaf, path->slots[0]));
 776                goto found;
 777        }
 778        ret = PTR_ERR(item);
 779        if (ret != -EFBIG && ret != -ENOENT)
 780                goto fail_unlock;
 781
 782        if (ret == -EFBIG) {
 783                u32 item_size;
 784                /* we found one, but it isn't big enough yet */
 785                leaf = path->nodes[0];
 786                item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 787                if ((item_size / csum_size) >=
 788                    MAX_CSUM_ITEMS(fs_info, csum_size)) {
 789                        /* already at max size, make a new one */
 790                        goto insert;
 791                }
 792        } else {
 793                int slot = path->slots[0] + 1;
 794                /* we didn't find a csum item, insert one */
 795                nritems = btrfs_header_nritems(path->nodes[0]);
 796                if (!nritems || (path->slots[0] >= nritems - 1)) {
 797                        ret = btrfs_next_leaf(root, path);
 798                        if (ret == 1)
 799                                found_next = 1;
 800                        if (ret != 0)
 801                                goto insert;
 802                        slot = path->slots[0];
 803                }
 804                btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 805                if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 806                    found_key.type != BTRFS_EXTENT_CSUM_KEY) {
 807                        found_next = 1;
 808                        goto insert;
 809                }
 810                next_offset = found_key.offset;
 811                found_next = 1;
 812                goto insert;
 813        }
 814
 815        /*
 816         * at this point, we know the tree has an item, but it isn't big
 817         * enough yet to put our csum in.  Grow it
 818         */
 819        btrfs_release_path(path);
 820        ret = btrfs_search_slot(trans, root, &file_key, path,
 821                                csum_size, 1);
 822        if (ret < 0)
 823                goto fail_unlock;
 824
 825        if (ret > 0) {
 826                if (path->slots[0] == 0)
 827                        goto insert;
 828                path->slots[0]--;
 829        }
 830
 831        leaf = path->nodes[0];
 832        btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 833        csum_offset = (bytenr - found_key.offset) >>
 834                        fs_info->sb->s_blocksize_bits;
 835
 836        if (found_key.type != BTRFS_EXTENT_CSUM_KEY ||
 837            found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
 838            csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) {
 839                goto insert;
 840        }
 841
 842        if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) /
 843            csum_size) {
 844                int extend_nr;
 845                u64 tmp;
 846                u32 diff;
 847                u32 free_space;
 848
 849                if (btrfs_leaf_free_space(fs_info, leaf) <
 850                                 sizeof(struct btrfs_item) + csum_size * 2)
 851                        goto insert;
 852
 853                free_space = btrfs_leaf_free_space(fs_info, leaf) -
 854                                         sizeof(struct btrfs_item) - csum_size;
 855                tmp = sums->len - total_bytes;
 856                tmp >>= fs_info->sb->s_blocksize_bits;
 857                WARN_ON(tmp < 1);
 858
 859                extend_nr = max_t(int, 1, (int)tmp);
 860                diff = (csum_offset + extend_nr) * csum_size;
 861                diff = min(diff,
 862                           MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size);
 863
 864                diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 865                diff = min(free_space, diff);
 866                diff /= csum_size;
 867                diff *= csum_size;
 868
 869                btrfs_extend_item(fs_info, path, diff);
 870                ret = 0;
 871                goto csum;
 872        }
 873
 874insert:
 875        btrfs_release_path(path);
 876        csum_offset = 0;
 877        if (found_next) {
 878                u64 tmp;
 879
 880                tmp = sums->len - total_bytes;
 881                tmp >>= fs_info->sb->s_blocksize_bits;
 882                tmp = min(tmp, (next_offset - file_key.offset) >>
 883                                         fs_info->sb->s_blocksize_bits);
 884
 885                tmp = max_t(u64, 1, tmp);
 886                tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size));
 887                ins_size = csum_size * tmp;
 888        } else {
 889                ins_size = csum_size;
 890        }
 891        path->leave_spinning = 1;
 892        ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 893                                      ins_size);
 894        path->leave_spinning = 0;
 895        if (ret < 0)
 896                goto fail_unlock;
 897        if (WARN_ON(ret != 0))
 898                goto fail_unlock;
 899        leaf = path->nodes[0];
 900csum:
 901        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 902        item_end = (struct btrfs_csum_item *)((unsigned char *)item +
 903                                      btrfs_item_size_nr(leaf, path->slots[0]));
 904        item = (struct btrfs_csum_item *)((unsigned char *)item +
 905                                          csum_offset * csum_size);
 906found:
 907        ins_size = (u32)(sums->len - total_bytes) >>
 908                   fs_info->sb->s_blocksize_bits;
 909        ins_size *= csum_size;
 910        ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item,
 911                              ins_size);
 912        write_extent_buffer(leaf, sums->sums + index, (unsigned long)item,
 913                            ins_size);
 914
 915        ins_size /= csum_size;
 916        total_bytes += ins_size * fs_info->sectorsize;
 917        index += ins_size;
 918
 919        btrfs_mark_buffer_dirty(path->nodes[0]);
 920        if (total_bytes < sums->len) {
 921                btrfs_release_path(path);
 922                cond_resched();
 923                goto again;
 924        }
 925out:
 926        btrfs_free_path(path);
 927        return ret;
 928
 929fail_unlock:
 930        goto out;
 931}
 932
 933void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 934                                     const struct btrfs_path *path,
 935                                     struct btrfs_file_extent_item *fi,
 936                                     const bool new_inline,
 937                                     struct extent_map *em)
 938{
 939        struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
 940        struct btrfs_root *root = inode->root;
 941        struct extent_buffer *leaf = path->nodes[0];
 942        const int slot = path->slots[0];
 943        struct btrfs_key key;
 944        u64 extent_start, extent_end;
 945        u64 bytenr;
 946        u8 type = btrfs_file_extent_type(leaf, fi);
 947        int compress_type = btrfs_file_extent_compression(leaf, fi);
 948
 949        em->bdev = fs_info->fs_devices->latest_bdev;
 950        btrfs_item_key_to_cpu(leaf, &key, slot);
 951        extent_start = key.offset;
 952
 953        if (type == BTRFS_FILE_EXTENT_REG ||
 954            type == BTRFS_FILE_EXTENT_PREALLOC) {
 955                extent_end = extent_start +
 956                        btrfs_file_extent_num_bytes(leaf, fi);
 957        } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 958                size_t size;
 959                size = btrfs_file_extent_inline_len(leaf, slot, fi);
 960                extent_end = ALIGN(extent_start + size,
 961                                   fs_info->sectorsize);
 962        }
 963
 964        em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
 965        if (type == BTRFS_FILE_EXTENT_REG ||
 966            type == BTRFS_FILE_EXTENT_PREALLOC) {
 967                em->start = extent_start;
 968                em->len = extent_end - extent_start;
 969                em->orig_start = extent_start -
 970                        btrfs_file_extent_offset(leaf, fi);
 971                em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
 972                bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 973                if (bytenr == 0) {
 974                        em->block_start = EXTENT_MAP_HOLE;
 975                        return;
 976                }
 977                if (compress_type != BTRFS_COMPRESS_NONE) {
 978                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 979                        em->compress_type = compress_type;
 980                        em->block_start = bytenr;
 981                        em->block_len = em->orig_block_len;
 982                } else {
 983                        bytenr += btrfs_file_extent_offset(leaf, fi);
 984                        em->block_start = bytenr;
 985                        em->block_len = em->len;
 986                        if (type == BTRFS_FILE_EXTENT_PREALLOC)
 987                                set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
 988                }
 989        } else if (type == BTRFS_FILE_EXTENT_INLINE) {
 990                em->block_start = EXTENT_MAP_INLINE;
 991                em->start = extent_start;
 992                em->len = extent_end - extent_start;
 993                /*
 994                 * Initialize orig_start and block_len with the same values
 995                 * as in inode.c:btrfs_get_extent().
 996                 */
 997                em->orig_start = EXTENT_MAP_HOLE;
 998                em->block_len = (u64)-1;
 999                if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) {
1000                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
1001                        em->compress_type = compress_type;
1002                }
1003        } else {
1004                btrfs_err(fs_info,
1005                          "unknown file extent item type %d, inode %llu, offset %llu, "
1006                          "root %llu", type, btrfs_ino(inode), extent_start,
1007                          root->root_key.objectid);
1008        }
1009}
1010