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  * Created by Gao Xiang <gaoxiang25@huawei.com>
   6  */
   7 #include "internal.h"
   8 #include <asm/unaligned.h>
   9 #include <trace/events/erofs.h>
  10
  11 int z_erofs_fill_inode(struct inode *inode)
  12 {
  13         struct erofs_inode *const vi = EROFS_I(inode);
  14
  15         if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
  16                 vi->z_advise = 0;
  17                 vi->z_algorithmtype[0] = 0;
  18                 vi->z_algorithmtype[1] = 0;
  19                 vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
  20                 vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
  21                 vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
  22                 set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
  23         }
  24
  25         inode->i_mapping->a_ops = &z_erofs_aops;
  26         return 0;
  27 }
  28
  29 static int z_erofs_fill_inode_lazy(struct inode *inode)
  30 {
  31         struct erofs_inode *const vi = EROFS_I(inode);
  32         struct super_block *const sb = inode->i_sb;
  33         int err;
  34         erofs_off_t pos;
  35         struct page *page;
  36         void *kaddr;
  37         struct z_erofs_map_header *h;
  38
  39         if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
  40                 return 0;
  41
  42         if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
  43                 return -ERESTARTSYS;
  44
  45         err = 0;
  46         if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
  47                 goto out_unlock;
  48
  49         DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
  50
  51         pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
  52                     vi->xattr_isize, 8);
  53         page = erofs_get_meta_page(sb, erofs_blknr(pos));
  54         if (IS_ERR(page)) {
  55                 err = PTR_ERR(page);
  56                 goto out_unlock;
  57         }
  58
  59         kaddr = kmap_atomic(page);
  60
  61         h = kaddr + erofs_blkoff(pos);
  62         vi->z_advise = le16_to_cpu(h->h_advise);
  63         vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
  64         vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
  65
  66         if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
  67                 erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
  68                           vi->z_algorithmtype[0], vi->nid);
  69                 err = -EOPNOTSUPP;
  70                 goto unmap_done;
  71         }
  72
  73         vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
  74         vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits +
  75                                         ((h->h_clusterbits >> 3) & 3);
  76
  77         if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
  78                 erofs_err(sb, "unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
  79                           vi->z_physical_clusterbits[0], vi->nid);
  80                 err = -EOPNOTSUPP;
  81                 goto unmap_done;
  82         }
  83
  84         vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
  85                                         ((h->h_clusterbits >> 5) & 7);
  86         set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
  87 unmap_done:
  88         kunmap_atomic(kaddr);
  89         unlock_page(page);
  90         put_page(page);
  91 out_unlock:
  92         clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
  93         return err;
  94 }
  95
  96 struct z_erofs_maprecorder {
  97         struct inode *inode;
  98         struct erofs_map_blocks *map;
  99         void *kaddr;
 100
 101         unsigned long lcn;
 102         /* compression extent information gathered */
 103         u8  type;
 104         u16 clusterofs;
 105         u16 delta[2];
 106         erofs_blk_t pblk;
 107 };
 108
 109 static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
 110                                   erofs_blk_t eblk)
 111 {
 112         struct super_block *const sb = m->inode->i_sb;
 113         struct erofs_map_blocks *const map = m->map;
 114         struct page *mpage = map->mpage;
 115
 116         if (mpage) {
 117                 if (mpage->index == eblk) {
 118                         if (!m->kaddr)
 119                                 m->kaddr = kmap_atomic(mpage);
 120                         return 0;
 121                 }
 122
 123                 if (m->kaddr) {
 124                         kunmap_atomic(m->kaddr);
 125                         m->kaddr = NULL;
 126                 }
 127                 put_page(mpage);
 128         }
 129
 130         mpage = erofs_get_meta_page(sb, eblk);
 131         if (IS_ERR(mpage)) {
 132                 map->mpage = NULL;
 133                 return PTR_ERR(mpage);
 134         }
 135         m->kaddr = kmap_atomic(mpage);
 136         unlock_page(mpage);
 137         map->mpage = mpage;
 138         return 0;
 139 }
 140
 141 static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 142                                          unsigned long lcn)
 143 {
 144         struct inode *const inode = m->inode;
 145         struct erofs_inode *const vi = EROFS_I(inode);
 146         const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
 147         const erofs_off_t pos =
 148                 Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
 149                                                vi->xattr_isize) +
 150                 lcn * sizeof(struct z_erofs_vle_decompressed_index);
 151         struct z_erofs_vle_decompressed_index *di;
 152         unsigned int advise, type;
 153         int err;
 154
 155         err = z_erofs_reload_indexes(m, erofs_blknr(pos));
 156         if (err)
 157                 return err;
 158
 159         m->lcn = lcn;
 160         di = m->kaddr + erofs_blkoff(pos);
 161
 162         advise = le16_to_cpu(di->di_advise);
 163         type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
 164                 ((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
 165         switch (type) {
 166         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 167                 m->clusterofs = 1 << vi->z_logical_clusterbits;
 168                 m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
 169                 m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
 170                 break;
 171         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 172         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 173                 m->clusterofs = le16_to_cpu(di->di_clusterofs);
 174                 m->pblk = le32_to_cpu(di->di_u.blkaddr);
 175                 break;
 176         default:
 177                 DBG_BUGON(1);
 178                 return -EOPNOTSUPP;
 179         }
 180         m->type = type;
 181         return 0;
 182 }
 183
 184 static unsigned int decode_compactedbits(unsigned int lobits,
 185                                          unsigned int lomask,
 186                                          u8 *in, unsigned int pos, u8 *type)
 187 {
 188         const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
 189         const unsigned int lo = v & lomask;
 190
 191         *type = (v >> lobits) & 3;
 192         return lo;
 193 }
 194
 195 static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 196                                   unsigned int amortizedshift,
 197                                   unsigned int eofs)
 198 {
 199         struct erofs_inode *const vi = EROFS_I(m->inode);
 200         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 201         const unsigned int lomask = (1 << lclusterbits) - 1;
 202         unsigned int vcnt, base, lo, encodebits, nblk;
 203         int i;
 204         u8 *in, type;
 205
 206         if (1 << amortizedshift == 4)
 207                 vcnt = 2;
 208         else if (1 << amortizedshift == 2 && lclusterbits == 12)
 209                 vcnt = 16;
 210         else
 211                 return -EOPNOTSUPP;
 212
 213         encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
 214         base = round_down(eofs, vcnt << amortizedshift);
 215         in = m->kaddr + base;
 216
 217         i = (eofs - base) >> amortizedshift;
 218
 219         lo = decode_compactedbits(lclusterbits, lomask,
 220                                   in, encodebits * i, &type);
 221         m->type = type;
 222         if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
 223                 m->clusterofs = 1 << lclusterbits;
 224                 if (i + 1 != vcnt) {
 225                         m->delta[0] = lo;
 226                         return 0;
 227                 }
 228                 /*
 229                  * since the last lcluster in the pack is special,
 230                  * of which lo saves delta[1] rather than delta[0].
 231                  * Hence, get delta[0] by the previous lcluster indirectly.
 232                  */
 233                 lo = decode_compactedbits(lclusterbits, lomask,
 234                                           in, encodebits * (i - 1), &type);
 235                 if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
 236                         lo = 0;
 237                 m->delta[0] = lo + 1;
 238                 return 0;
 239         }
 240         m->clusterofs = lo;
 241         m->delta[0] = 0;
 242         /* figout out blkaddr (pblk) for HEAD lclusters */
 243         nblk = 1;
 244         while (i > 0) {
 245                 --i;
 246                 lo = decode_compactedbits(lclusterbits, lomask,
 247                                           in, encodebits * i, &type);
 248                 if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
 249                         i -= lo;
 250
 251                 if (i >= 0)
 252                         ++nblk;
 253         }
 254         in += (vcnt << amortizedshift) - sizeof(__le32);
 255         m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
 256         return 0;
 257 }
 258
 259 static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 260                                             unsigned long lcn)
 261 {
 262         struct inode *const inode = m->inode;
 263         struct erofs_inode *const vi = EROFS_I(inode);
 264         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 265         const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
 266                                         vi->inode_isize + vi->xattr_isize, 8) +
 267                 sizeof(struct z_erofs_map_header);
 268         const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
 269         unsigned int compacted_4b_initial, compacted_2b;
 270         unsigned int amortizedshift;
 271         erofs_off_t pos;
 272         int err;
 273
 274         if (lclusterbits != 12)
 275                 return -EOPNOTSUPP;
 276
 277         if (lcn >= totalidx)
 278                 return -EINVAL;
 279
 280         m->lcn = lcn;
 281         /* used to align to 32-byte (compacted_2b) alignment */
 282         compacted_4b_initial = (32 - ebase % 32) / 4;
 283         if (compacted_4b_initial == 32 / 4)
 284                 compacted_4b_initial = 0;
 285
 286         if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
 287                 compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
 288         else
 289                 compacted_2b = 0;
 290
 291         pos = ebase;
 292         if (lcn < compacted_4b_initial) {
 293                 amortizedshift = 2;
 294                 goto out;
 295         }
 296         pos += compacted_4b_initial * 4;
 297         lcn -= compacted_4b_initial;
 298
 299         if (lcn < compacted_2b) {
 300                 amortizedshift = 1;
 301                 goto out;
 302         }
 303         pos += compacted_2b * 2;
 304         lcn -= compacted_2b;
 305         amortizedshift = 2;
 306 out:
 307         pos += lcn * (1 << amortizedshift);
 308         err = z_erofs_reload_indexes(m, erofs_blknr(pos));
 309         if (err)
 310                 return err;
 311         return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos));
 312 }
 313
 314 static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 315                                           unsigned int lcn)
 316 {
 317         const unsigned int datamode = EROFS_I(m->inode)->datalayout;
 318
 319         if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
 320                 return legacy_load_cluster_from_disk(m, lcn);
 321
 322         if (datamode == EROFS_INODE_FLAT_COMPRESSION)
 323                 return compacted_load_cluster_from_disk(m, lcn);
 324
 325         return -EINVAL;
 326 }
 327
 328 static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
 329                                    unsigned int lookback_distance)
 330 {
 331         struct erofs_inode *const vi = EROFS_I(m->inode);
 332         struct erofs_map_blocks *const map = m->map;
 333         const unsigned int lclusterbits = vi->z_logical_clusterbits;
 334         unsigned long lcn = m->lcn;
 335         int err;
 336
 337         if (lcn < lookback_distance) {
 338                 erofs_err(m->inode->i_sb,
 339                           "bogus lookback distance @ nid %llu", vi->nid);
 340                 DBG_BUGON(1);
 341                 return -EFSCORRUPTED;
 342         }
 343
 344         /* load extent head logical cluster if needed */
 345         lcn -= lookback_distance;
 346         err = z_erofs_load_cluster_from_disk(m, lcn);
 347         if (err)
 348                 return err;
 349
 350         switch (m->type) {
 351         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 352                 if (!m->delta[0]) {
 353                         erofs_err(m->inode->i_sb,
 354                                   "invalid lookback distance 0 @ nid %llu",
 355                                   vi->nid);
 356                         DBG_BUGON(1);
 357                         return -EFSCORRUPTED;
 358                 }
 359                 return z_erofs_extent_lookback(m, m->delta[0]);
 360         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 361                 map->m_flags &= ~EROFS_MAP_ZIPPED;
 362                 fallthrough;
 363         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 364                 map->m_la = (lcn << lclusterbits) | m->clusterofs;
 365                 break;
 366         default:
 367                 erofs_err(m->inode->i_sb,
 368                           "unknown type %u @ lcn %lu of nid %llu",
 369                           m->type, lcn, vi->nid);
 370                 DBG_BUGON(1);
 371                 return -EOPNOTSUPP;
 372         }
 373         return 0;
 374 }
 375
 376 int z_erofs_map_blocks_iter(struct inode *inode,
 377                             struct erofs_map_blocks *map,
 378                             int flags)
 379 {
 380         struct erofs_inode *const vi = EROFS_I(inode);
 381         struct z_erofs_maprecorder m = {
 382                 .inode = inode,
 383                 .map = map,
 384         };
 385         int err = 0;
 386         unsigned int lclusterbits, endoff;
 387         unsigned long long ofs, end;
 388
 389         trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
 390
 391         /* when trying to read beyond EOF, leave it unmapped */
 392         if (map->m_la >= inode->i_size) {
 393                 map->m_llen = map->m_la + 1 - inode->i_size;
 394                 map->m_la = inode->i_size;
 395                 map->m_flags = 0;
 396                 goto out;
 397         }
 398
 399         err = z_erofs_fill_inode_lazy(inode);
 400         if (err)
 401                 goto out;
 402
 403         lclusterbits = vi->z_logical_clusterbits;
 404         ofs = map->m_la;
 405         m.lcn = ofs >> lclusterbits;
 406         endoff = ofs & ((1 << lclusterbits) - 1);
 407
 408         err = z_erofs_load_cluster_from_disk(&m, m.lcn);
 409         if (err)
 410                 goto unmap_out;
 411
 412         map->m_flags = EROFS_MAP_ZIPPED;        /* by default, compressed */
 413         end = (m.lcn + 1ULL) << lclusterbits;
 414
 415         switch (m.type) {
 416         case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
 417                 if (endoff >= m.clusterofs)
 418                         map->m_flags &= ~EROFS_MAP_ZIPPED;
 419                 fallthrough;
 420         case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
 421                 if (endoff >= m.clusterofs) {
 422                         map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
 423                         break;
 424                 }
 425                 /* m.lcn should be >= 1 if endoff < m.clusterofs */
 426                 if (!m.lcn) {
 427                         erofs_err(inode->i_sb,
 428                                   "invalid logical cluster 0 at nid %llu",
 429                                   vi->nid);
 430                         err = -EFSCORRUPTED;
 431                         goto unmap_out;
 432                 }
 433                 end = (m.lcn << lclusterbits) | m.clusterofs;
 434                 map->m_flags |= EROFS_MAP_FULL_MAPPED;
 435                 m.delta[0] = 1;
 436                 fallthrough;
 437         case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 438                 /* get the correspoinding first chunk */
 439                 err = z_erofs_extent_lookback(&m, m.delta[0]);
 440                 if (err)
 441                         goto unmap_out;
 442                 break;
 443         default:
 444                 erofs_err(inode->i_sb,
 445                           "unknown type %u @ offset %llu of nid %llu",
 446                           m.type, ofs, vi->nid);
 447                 err = -EOPNOTSUPP;
 448                 goto unmap_out;
 449         }
 450
 451         map->m_llen = end - map->m_la;
 452         map->m_plen = 1 << lclusterbits;
 453         map->m_pa = blknr_to_addr(m.pblk);
 454         map->m_flags |= EROFS_MAP_MAPPED;
 455
 456 unmap_out:
 457         if (m.kaddr)
 458                 kunmap_atomic(m.kaddr);
 459
 460 out:
 461         erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
 462                   __func__, map->m_la, map->m_pa,
 463                   map->m_llen, map->m_plen, map->m_flags);
 464
 465         trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
 466
 467         /* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
 468         DBG_BUGON(err < 0 && err != -ENOMEM);
 469         return err;
 470 }
 471