fs/erofs/zmap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2018-2019 HUAWEI, Inc.
   4  *             https://www.huawei.com/
   5  */
   6 #include "internal.h"
   7 #include <asm/unaligned.h>
   8 #include <trace/events/erofs.h>
   9
  10 int z_erofs_fill_inode(struct inode *inode)
  11 {
  12         struct erofs_inode *const vi = EROFS_I(inode);
  13         struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
  14
  15         if (!erofs_sb_has_big_pcluster(sbi) &&
  16             vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
  17                 vi->z_advise = 0;
  18                 vi->z_algorithmtype[0] = 0;
  19                 vi->z_algorithmtype[1] = 0;
  20                 vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
  21                 set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
  22         }
  23         inode->i_mapping->a_ops = &z_erofs_aops;
  24         return 0;
  25 }
  26
  27 static int z_erofs_fill_inode_lazy(struct inode *inode)
  28 {
  29         struct erofs_inode *const vi = EROFS_I(inode);
  30         struct super_block *const sb = inode->i_sb;
  31         int err;
  32         erofs_off_t pos;
  33         struct page *page;
  34         void *kaddr;
  35         struct z_erofs_map_header *h;
  36
  37         if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
  38                 /*
  39                  * paired with smp_mb() at the end of the function to ensure
  40                  * fields will only be observed after the bit is set.
  41                  */
  42                 smp_mb();
  43                 return 0;
  44         }
  45
  46         if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
  47                 return -ERESTARTSYS;
  48
  49         err = 0;
  50         if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
  51                 goto out_unlock;
  52
  53         DBG_BUGON(!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
  54                   vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
  55
  56         pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
  57                     vi->xattr_isize, 8);
  58         page = erofs_get_meta_page(sb, erofs_blknr(pos));
  59         if (IS_ERR(page)) {
  60                 err = PTR_ERR(page);
  61                 goto out_unlock;
  62         }
  63
  64         kaddr = kmap_atomic(page);
  65
  66         h = kaddr + erofs_blkoff(pos);
  67         vi->z_advise = le16_to_cpu(h->h_advise);
  68         vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
  69         vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
  70
  71         if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
  72                 erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
  73                           vi->z_algorithmtype[0], vi->nid);
  74                 err = -EOPNOTSUPP;
  75                 goto unmap_done;
  76         }
  77
  78         vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
  79         if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
  80             vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
  81                             Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
  82                 erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
  83                           vi->nid);
  84                 err = -EFSCORRUPTED;
  85                 goto unmap_done;
  86         }
  87         if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
  88             !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
  89             !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
  90                 erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
  91                           vi->nid);
  92                 err = -EFSCORRUPTED;
  93                 goto unmap_done;
  94         }
  95         /* paired with smp_mb() at the beginning of the function */
  96         smp_mb();
  97         set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
  98 unmap_done:
  99         kunmap_atomic(kaddr);
 100         unlock_page(page);
 101         put_page(page);
 102 out_unlock:
 103         clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
 104         return err;
 105 }
 106
 107 struct z_erofs_maprecorder {
 108         struct inode *inode;
 109         struct erofs_map_blocks *map;
 110         void *kaddr;
 111
 112         unsigned long lcn;
 113         /* compression extent information gathered */
 114         u8  type;
 115         u16 clusterofs;
 116         u16 delta[2];
 117         erofs_blk_t pblk, compressedlcs;
 118 };
 119
 120 static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
 121                                   erofs_blk_t eblk)
 122 {
 123         struct super_block *const sb = m->inode->i_sb;
 124         struct erofs_map_blocks *const map = m->map;
 125         struct page *mpage = map->mpage;
 126
 127         if (mpage) {
 128                 if (mpage->index == eblk) {
 129                         if (!m->kaddr)
 130                                 m->kaddr = kmap_atomic(mpage);
 131                         return 0;
 132                 }
 133
 134                 if (m->kaddr) {
 135                         kunmap_atomic(m->kaddr);
 136                         m->kaddr = NULL;
 137                 }
 138                 put_page(mpage);
 139         }
 140
 141         mpage = erofs_get_meta_page(sb, eblk);
 142         if (IS_ERR(mpage)) {
 143                 map->mpage = NULL;
 144                 return PTR_ERR(mpage);
 145         }
 146         m->kaddr = kmap_atomic(mpage);
 147         unlock_page(mpage);
 148         map->mpage = mpage;
 149         return 0;
 150 }
 151
 152 static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 153                                          unsigned long lcn)
 154 {
 155         struct inode *const inode = m->inode;
 156         struct erofs_inode *const vi = EROFS_I(inode);
 157         const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
 158         const erofs_off_t pos =
 159                 Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
 160                                                vi->xattr_isize) +
 161                 lcn * sizeof(struct z_erofs_vle_decompressed_index);
 162         struct z_erofs_vle_decompressed_index *di;
 163         unsigned int advise, type;
 164         int err;
 165
 166         err = z_erofs_reload_indexes(m, erofs_blknr(pos));
 167         if (err)
 168                 return err;
 169
 170         m->lcn = lcn;
 171         di = m->kaddr + erofs_blkoff(pos);
 172
 173         advise = le16_to_cpu(di->di_advise);
 174         type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
 175                 ((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
 176         switch (type) {
 177         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 178                 m->clusterofs = 1 << vi->z_logical_clusterbits;
 179                 m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
 180                 if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
 181                         if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
 182                                 DBG_BUGON(1);
 183                                 return -EFSCORRUPTED;
 184                         }
 185                         m->compressedlcs = m->delta[0] &
 186                                 ~Z_EROFS_VLE_DI_D0_CBLKCNT;
 187                         m->delta[0] = 1;
 188                 }
 189                 m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
 190                 break;
 191         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 192         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 193                 m->clusterofs = le16_to_cpu(di->di_clusterofs);
 194                 m->pblk = le32_to_cpu(di->di_u.blkaddr);
 195                 break;
 196         default:
 197                 DBG_BUGON(1);
 198                 return -EOPNOTSUPP;
 199         }
 200         m->type = type;
 201         return 0;
 202 }
 203
 204 static unsigned int decode_compactedbits(unsigned int lobits,
 205                                          unsigned int lomask,
 206                                          u8 *in, unsigned int pos, u8 *type)
 207 {
 208         const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
 209         const unsigned int lo = v & lomask;
 210
 211         *type = (v >> lobits) & 3;
 212         return lo;
 213 }
 214
 215 static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 216                                   unsigned int amortizedshift,
 217                                   unsigned int eofs)
 218 {
 219         struct erofs_inode *const vi = EROFS_I(m->inode);
 220         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 221         const unsigned int lomask = (1 << lclusterbits) - 1;
 222         unsigned int vcnt, base, lo, encodebits, nblk;
 223         int i;
 224         u8 *in, type;
 225         bool big_pcluster;
 226
 227         if (1 << amortizedshift == 4)
 228                 vcnt = 2;
 229         else if (1 << amortizedshift == 2 && lclusterbits == 12)
 230                 vcnt = 16;
 231         else
 232                 return -EOPNOTSUPP;
 233
 234         big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
 235         encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
 236         base = round_down(eofs, vcnt << amortizedshift);
 237         in = m->kaddr + base;
 238
 239         i = (eofs - base) >> amortizedshift;
 240
 241         lo = decode_compactedbits(lclusterbits, lomask,
 242                                   in, encodebits * i, &type);
 243         m->type = type;
 244         if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
 245                 m->clusterofs = 1 << lclusterbits;
 246                 if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
 247                         if (!big_pcluster) {
 248                                 DBG_BUGON(1);
 249                                 return -EFSCORRUPTED;
 250                         }
 251                         m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
 252                         m->delta[0] = 1;
 253                         return 0;
 254                 } else if (i + 1 != (int)vcnt) {
 255                         m->delta[0] = lo;
 256                         return 0;
 257                 }
 258                 /*
 259                  * since the last lcluster in the pack is special,
 260                  * of which lo saves delta[1] rather than delta[0].
 261                  * Hence, get delta[0] by the previous lcluster indirectly.
 262                  */
 263                 lo = decode_compactedbits(lclusterbits, lomask,
 264                                           in, encodebits * (i - 1), &type);
 265                 if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
 266                         lo = 0;
 267                 else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
 268                         lo = 1;
 269                 m->delta[0] = lo + 1;
 270                 return 0;
 271         }
 272         m->clusterofs = lo;
 273         m->delta[0] = 0;
 274         /* figout out blkaddr (pblk) for HEAD lclusters */
 275         if (!big_pcluster) {
 276                 nblk = 1;
 277                 while (i > 0) {
 278                         --i;
 279                         lo = decode_compactedbits(lclusterbits, lomask,
 280                                                   in, encodebits * i, &type);
 281                         if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
 282                                 i -= lo;
 283
 284                         if (i >= 0)
 285                                 ++nblk;
 286                 }
 287         } else {
 288                 nblk = 0;
 289                 while (i > 0) {
 290                         --i;
 291                         lo = decode_compactedbits(lclusterbits, lomask,
 292                                                   in, encodebits * i, &type);
 293                         if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
 294                                 if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
 295                                         --i;
 296                                         nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
 297                                         continue;
 298                                 }
 299                                 /* bigpcluster shouldn't have plain d0 == 1 */
 300                                 if (lo <= 1) {
 301                                         DBG_BUGON(1);
 302                                         return -EFSCORRUPTED;
 303                                 }
 304                                 i -= lo - 2;
 305                                 continue;
 306                         }
 307                         ++nblk;
 308                 }
 309         }
 310         in += (vcnt << amortizedshift) - sizeof(__le32);
 311         m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
 312         return 0;
 313 }
 314
 315 static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 316                                             unsigned long lcn)
 317 {
 318         struct inode *const inode = m->inode;
 319         struct erofs_inode *const vi = EROFS_I(inode);
 320         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 321         const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
 322                                         vi->inode_isize + vi->xattr_isize, 8) +
 323                 sizeof(struct z_erofs_map_header);
 324         const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
 325         unsigned int compacted_4b_initial, compacted_2b;
 326         unsigned int amortizedshift;
 327         erofs_off_t pos;
 328         int err;
 329
 330         if (lclusterbits != 12)
 331                 return -EOPNOTSUPP;
 332
 333         if (lcn >= totalidx)
 334                 return -EINVAL;
 335
 336         m->lcn = lcn;
 337         /* used to align to 32-byte (compacted_2b) alignment */
 338         compacted_4b_initial = (32 - ebase % 32) / 4;
 339         if (compacted_4b_initial == 32 / 4)
 340                 compacted_4b_initial = 0;
 341
 342         if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
 343                 compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
 344         else
 345                 compacted_2b = 0;
 346
 347         pos = ebase;
 348         if (lcn < compacted_4b_initial) {
 349                 amortizedshift = 2;
 350                 goto out;
 351         }
 352         pos += compacted_4b_initial * 4;
 353         lcn -= compacted_4b_initial;
 354
 355         if (lcn < compacted_2b) {
 356                 amortizedshift = 1;
 357                 goto out;
 358         }
 359         pos += compacted_2b * 2;
 360         lcn -= compacted_2b;
 361         amortizedshift = 2;
 362 out:
 363         pos += lcn * (1 << amortizedshift);
 364         err = z_erofs_reload_indexes(m, erofs_blknr(pos));
 365         if (err)
 366                 return err;
 367         return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos));
 368 }
 369
 370 static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 371                                           unsigned int lcn)
 372 {
 373         const unsigned int datamode = EROFS_I(m->inode)->datalayout;
 374
 375         if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
 376                 return legacy_load_cluster_from_disk(m, lcn);
 377
 378         if (datamode == EROFS_INODE_FLAT_COMPRESSION)
 379                 return compacted_load_cluster_from_disk(m, lcn);
 380
 381         return -EINVAL;
 382 }
 383
 384 static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 385                                    unsigned int lookback_distance)
 386 {
 387         struct erofs_inode *const vi = EROFS_I(m->inode);
 388         struct erofs_map_blocks *const map = m->map;
 389         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 390         unsigned long lcn = m->lcn;
 391         int err;
 392
 393         if (lcn < lookback_distance) {
 394                 erofs_err(m->inode->i_sb,
 395                           "bogus lookback distance @ nid %llu", vi->nid);
 396                 DBG_BUGON(1);
 397                 return -EFSCORRUPTED;
 398         }
 399
 400         /* load extent head logical cluster if needed */
 401         lcn -= lookback_distance;
 402         err = z_erofs_load_cluster_from_disk(m, lcn);
 403         if (err)
 404                 return err;
 405
 406         switch (m->type) {
 407         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 408                 if (!m->delta[0]) {
 409                         erofs_err(m->inode->i_sb,
 410                                   "invalid lookback distance 0 @ nid %llu",
 411                                   vi->nid);
 412                         DBG_BUGON(1);
 413                         return -EFSCORRUPTED;
 414                 }
 415                 return z_erofs_extent_lookback(m, m->delta[0]);
 416         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 417                 map->m_flags &= ~EROFS_MAP_ZIPPED;
 418                 fallthrough;
 419         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 420                 map->m_la = (lcn << lclusterbits) | m->clusterofs;
 421                 break;
 422         default:
 423                 erofs_err(m->inode->i_sb,
 424                           "unknown type %u @ lcn %lu of nid %llu",
 425                           m->type, lcn, vi->nid);
 426                 DBG_BUGON(1);
 427                 return -EOPNOTSUPP;
 428         }
 429         return 0;
 430 }
 431
 432 static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
 433                                             unsigned int initial_lcn)
 434 {
 435         struct erofs_inode *const vi = EROFS_I(m->inode);
 436         struct erofs_map_blocks *const map = m->map;
 437         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 438         unsigned long lcn;
 439         int err;
 440
 441         DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
 442                   m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
 443         if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
 444             !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
 445                 map->m_plen = 1 << lclusterbits;
 446                 return 0;
 447         }
 448
 449         lcn = m->lcn + 1;
 450         if (m->compressedlcs)
 451                 goto out;
 452
 453         err = z_erofs_load_cluster_from_disk(m, lcn);
 454         if (err)
 455                 return err;
 456
 457         /*
 458          * If the 1st NONHEAD lcluster has already been handled initially w/o
 459          * valid compressedlcs, which means at least it mustn't be CBLKCNT, or
 460          * an internal implemenatation error is detected.
 461          *
 462          * The following code can also handle it properly anyway, but let's
 463          * BUG_ON in the debugging mode only for developers to notice that.
 464          */
 465         DBG_BUGON(lcn == initial_lcn &&
 466                   m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
 467
 468         switch (m->type) {
 469         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 470         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 471                 /*
 472                  * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
 473                  * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
 474                  */
 475                 m->compressedlcs = 1;
 476                 break;
 477         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 478                 if (m->delta[0] != 1)
 479                         goto err_bonus_cblkcnt;
 480                 if (m->compressedlcs)
 481                         break;
 482                 fallthrough;
 483         default:
 484                 erofs_err(m->inode->i_sb,
 485                           "cannot found CBLKCNT @ lcn %lu of nid %llu",
 486                           lcn, vi->nid);
 487                 DBG_BUGON(1);
 488                 return -EFSCORRUPTED;
 489         }
 490 out:
 491         map->m_plen = m->compressedlcs << lclusterbits;
 492         return 0;
 493 err_bonus_cblkcnt:
 494         erofs_err(m->inode->i_sb,
 495                   "bogus CBLKCNT @ lcn %lu of nid %llu",
 496                   lcn, vi->nid);
 497         DBG_BUGON(1);
 498         return -EFSCORRUPTED;
 499 }
 500
 501 int z_erofs_map_blocks_iter(struct inode *inode,
 502                             struct erofs_map_blocks *map,
 503                             int flags)
 504 {
 505         struct erofs_inode *const vi = EROFS_I(inode);
 506         struct z_erofs_maprecorder m = {
 507                 .inode = inode,
 508                 .map = map,
 509         };
 510         int err = 0;
 511         unsigned int lclusterbits, endoff;
 512         unsigned long initial_lcn;
 513         unsigned long long ofs, end;
 514
 515         trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
 516
 517         /* when trying to read beyond EOF, leave it unmapped */
 518         if (map->m_la >= inode->i_size) {
 519                 map->m_llen = map->m_la + 1 - inode->i_size;
 520                 map->m_la = inode->i_size;
 521                 map->m_flags = 0;
 522                 goto out;
 523         }
 524
 525         err = z_erofs_fill_inode_lazy(inode);
 526         if (err)
 527                 goto out;
 528
 529         lclusterbits = vi->z_logical_clusterbits;
 530         ofs = map->m_la;
 531         initial_lcn = ofs >> lclusterbits;
 532         endoff = ofs & ((1 << lclusterbits) - 1);
 533
 534         err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
 535         if (err)
 536                 goto unmap_out;
 537
 538         map->m_flags = EROFS_MAP_ZIPPED;        /* by default, compressed */
 539         end = (m.lcn + 1ULL) << lclusterbits;
 540
 541         switch (m.type) {
 542         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 543                 if (endoff >= m.clusterofs)
 544                         map->m_flags &= ~EROFS_MAP_ZIPPED;
 545                 fallthrough;
 546         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 547                 if (endoff >= m.clusterofs) {
 548                         map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
 549                         break;
 550                 }
 551                 /* m.lcn should be >= 1 if endoff < m.clusterofs */
 552                 if (!m.lcn) {
 553                         erofs_err(inode->i_sb,
 554                                   "invalid logical cluster 0 at nid %llu",
 555                                   vi->nid);
 556                         err = -EFSCORRUPTED;
 557                         goto unmap_out;
 558                 }
 559                 end = (m.lcn << lclusterbits) | m.clusterofs;
 560                 map->m_flags |= EROFS_MAP_FULL_MAPPED;
 561                 m.delta[0] = 1;
 562                 fallthrough;
 563         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 564                 /* get the corresponding first chunk */
 565                 err = z_erofs_extent_lookback(&m, m.delta[0]);
 566                 if (err)
 567                         goto unmap_out;
 568                 break;
 569         default:
 570                 erofs_err(inode->i_sb,
 571                           "unknown type %u @ offset %llu of nid %llu",
 572                           m.type, ofs, vi->nid);
 573                 err = -EOPNOTSUPP;
 574                 goto unmap_out;
 575         }
 576
 577         map->m_llen = end - map->m_la;
 578         map->m_pa = blknr_to_addr(m.pblk);
 579         map->m_flags |= EROFS_MAP_MAPPED;
 580
 581         err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
 582         if (err)
 583                 goto out;
 584 unmap_out:
 585         if (m.kaddr)
 586                 kunmap_atomic(m.kaddr);
 587
 588 out:
 589         erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
 590                   __func__, map->m_la, map->m_pa,
 591                   map->m_llen, map->m_plen, map->m_flags);
 592
 593         trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
 594
 595         /* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
 596         DBG_BUGON(err < 0 && err != -ENOMEM);
 597         return err;
 598 }