fs/logfs/journal.c

   1 /*
   2  * fs/logfs/journal.c   - journal handling code
   3  *
   4  * As should be obvious for Linux kernel code, license is GPLv2
   5  *
   6  * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
   7  */
   8 #include "logfs.h"
   9
  10 static void logfs_calc_free(struct super_block *sb)
  11 {
  12         struct logfs_super *super = logfs_super(sb);
  13         u64 reserve, no_segs = super->s_no_segs;
  14         s64 free;
  15         int i;
  16
  17         /* superblock segments */
  18         no_segs -= 2;
  19         super->s_no_journal_segs = 0;
  20         /* journal */
  21         journal_for_each(i)
  22                 if (super->s_journal_seg[i]) {
  23                         no_segs--;
  24                         super->s_no_journal_segs++;
  25                 }
  26
  27         /* open segments plus one extra per level for GC */
  28         no_segs -= 2 * super->s_total_levels;
  29
  30         free = no_segs * (super->s_segsize - LOGFS_SEGMENT_RESERVE);
  31         free -= super->s_used_bytes;
  32         /* just a bit extra */
  33         free -= super->s_total_levels * 4096;
  34
  35         /* Bad blocks are 'paid' for with speed reserve - the filesystem
  36          * simply gets slower as bad blocks accumulate.  Until the bad blocks
  37          * exceed the speed reserve - then the filesystem gets smaller.
  38          */
  39         reserve = super->s_bad_segments + super->s_bad_seg_reserve;
  40         reserve *= super->s_segsize - LOGFS_SEGMENT_RESERVE;
  41         reserve = max(reserve, super->s_speed_reserve);
  42         free -= reserve;
  43         if (free < 0)
  44                 free = 0;
  45
  46         super->s_free_bytes = free;
  47 }
  48
  49 static void reserve_sb_and_journal(struct super_block *sb)
  50 {
  51         struct logfs_super *super = logfs_super(sb);
  52         struct btree_head32 *head = &super->s_reserved_segments;
  53         int i, err;
  54
  55         err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[0]), (void *)1,
  56                         GFP_KERNEL);
  57         BUG_ON(err);
  58
  59         err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[1]), (void *)1,
  60                         GFP_KERNEL);
  61         BUG_ON(err);
  62
  63         journal_for_each(i) {
  64                 if (!super->s_journal_seg[i])
  65                         continue;
  66                 err = btree_insert32(head, super->s_journal_seg[i], (void *)1,
  67                                 GFP_KERNEL);
  68                 BUG_ON(err);
  69         }
  70 }
  71
  72 static void read_dynsb(struct super_block *sb,
  73                 struct logfs_je_dynsb *dynsb)
  74 {
  75         struct logfs_super *super = logfs_super(sb);
  76
  77         super->s_gec            = be64_to_cpu(dynsb->ds_gec);
  78         super->s_sweeper        = be64_to_cpu(dynsb->ds_sweeper);
  79         super->s_victim_ino     = be64_to_cpu(dynsb->ds_victim_ino);
  80         super->s_rename_dir     = be64_to_cpu(dynsb->ds_rename_dir);
  81         super->s_rename_pos     = be64_to_cpu(dynsb->ds_rename_pos);
  82         super->s_used_bytes     = be64_to_cpu(dynsb->ds_used_bytes);
  83         super->s_generation     = be32_to_cpu(dynsb->ds_generation);
  84 }
  85
  86 static void read_anchor(struct super_block *sb,
  87                 struct logfs_je_anchor *da)
  88 {
  89         struct logfs_super *super = logfs_super(sb);
  90         struct inode *inode = super->s_master_inode;
  91         struct logfs_inode *li = logfs_inode(inode);
  92         int i;
  93
  94         super->s_last_ino = be64_to_cpu(da->da_last_ino);
  95         li->li_flags    = 0;
  96         li->li_height   = da->da_height;
  97         i_size_write(inode, be64_to_cpu(da->da_size));
  98         li->li_used_bytes = be64_to_cpu(da->da_used_bytes);
  99
 100         for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 101                 li->li_data[i] = be64_to_cpu(da->da_data[i]);
 102 }
 103
 104 static void read_erasecount(struct super_block *sb,
 105                 struct logfs_je_journal_ec *ec)
 106 {
 107         struct logfs_super *super = logfs_super(sb);
 108         int i;
 109
 110         journal_for_each(i)
 111                 super->s_journal_ec[i] = be32_to_cpu(ec->ec[i]);
 112 }
 113
 114 static int read_area(struct super_block *sb, struct logfs_je_area *a)
 115 {
 116         struct logfs_super *super = logfs_super(sb);
 117         struct logfs_area *area = super->s_area[a->gc_level];
 118         u64 ofs;
 119         u32 writemask = ~(super->s_writesize - 1);
 120
 121         if (a->gc_level >= LOGFS_NO_AREAS)
 122                 return -EIO;
 123         if (a->vim != VIM_DEFAULT)
 124                 return -EIO; /* TODO: close area and continue */
 125
 126         area->a_used_bytes = be32_to_cpu(a->used_bytes);
 127         area->a_written_bytes = area->a_used_bytes & writemask;
 128         area->a_segno = be32_to_cpu(a->segno);
 129         if (area->a_segno)
 130                 area->a_is_open = 1;
 131
 132         ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
 133         if (super->s_writesize > 1)
 134                 logfs_buf_recover(area, ofs, a + 1, super->s_writesize);
 135         else
 136                 logfs_buf_recover(area, ofs, NULL, 0);
 137         return 0;
 138 }
 139
 140 static void *unpack(void *from, void *to)
 141 {
 142         struct logfs_journal_header *jh = from;
 143         void *data = from + sizeof(struct logfs_journal_header);
 144         int err;
 145         size_t inlen, outlen;
 146
 147         inlen = be16_to_cpu(jh->h_len);
 148         outlen = be16_to_cpu(jh->h_datalen);
 149
 150         if (jh->h_compr == COMPR_NONE)
 151                 memcpy(to, data, inlen);
 152         else {
 153                 err = logfs_uncompress(data, to, inlen, outlen);
 154                 BUG_ON(err);
 155         }
 156         return to;
 157 }
 158
 159 static int __read_je_header(struct super_block *sb, u64 ofs,
 160                 struct logfs_journal_header *jh)
 161 {
 162         struct logfs_super *super = logfs_super(sb);
 163         size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize)
 164                 + MAX_JOURNAL_HEADER;
 165         u16 type, len, datalen;
 166         int err;
 167
 168         /* read header only */
 169         err = wbuf_read(sb, ofs, sizeof(*jh), jh);
 170         if (err)
 171                 return err;
 172         type = be16_to_cpu(jh->h_type);
 173         len = be16_to_cpu(jh->h_len);
 174         datalen = be16_to_cpu(jh->h_datalen);
 175         if (len > sb->s_blocksize)
 176                 return -EIO;
 177         if ((type < JE_FIRST) || (type > JE_LAST))
 178                 return -EIO;
 179         if (datalen > bufsize)
 180                 return -EIO;
 181         return 0;
 182 }
 183
 184 static int __read_je_payload(struct super_block *sb, u64 ofs,
 185                 struct logfs_journal_header *jh)
 186 {
 187         u16 len;
 188         int err;
 189
 190         len = be16_to_cpu(jh->h_len);
 191         err = wbuf_read(sb, ofs + sizeof(*jh), len, jh + 1);
 192         if (err)
 193                 return err;
 194         if (jh->h_crc != logfs_crc32(jh, len + sizeof(*jh), 4)) {
 195                 /* Old code was confused.  It forgot about the header length
 196                  * and stopped calculating the crc 16 bytes before the end
 197                  * of data - ick!
 198                  * FIXME: Remove this hack once the old code is fixed.
 199                  */
 200                 if (jh->h_crc == logfs_crc32(jh, len, 4))
 201                         WARN_ON_ONCE(1);
 202                 else
 203                         return -EIO;
 204         }
 205         return 0;
 206 }
 207
 208 /*
 209  * jh needs to be large enough to hold the complete entry, not just the header
 210  */
 211 static int __read_je(struct super_block *sb, u64 ofs,
 212                 struct logfs_journal_header *jh)
 213 {
 214         int err;
 215
 216         err = __read_je_header(sb, ofs, jh);
 217         if (err)
 218                 return err;
 219         return __read_je_payload(sb, ofs, jh);
 220 }
 221
 222 static int read_je(struct super_block *sb, u64 ofs)
 223 {
 224         struct logfs_super *super = logfs_super(sb);
 225         struct logfs_journal_header *jh = super->s_compressed_je;
 226         void *scratch = super->s_je;
 227         u16 type, datalen;
 228         int err;
 229
 230         err = __read_je(sb, ofs, jh);
 231         if (err)
 232                 return err;
 233         type = be16_to_cpu(jh->h_type);
 234         datalen = be16_to_cpu(jh->h_datalen);
 235
 236         switch (type) {
 237         case JE_DYNSB:
 238                 read_dynsb(sb, unpack(jh, scratch));
 239                 break;
 240         case JE_ANCHOR:
 241                 read_anchor(sb, unpack(jh, scratch));
 242                 break;
 243         case JE_ERASECOUNT:
 244                 read_erasecount(sb, unpack(jh, scratch));
 245                 break;
 246         case JE_AREA:
 247                 read_area(sb, unpack(jh, scratch));
 248                 break;
 249         case JE_OBJ_ALIAS:
 250                 err = logfs_load_object_aliases(sb, unpack(jh, scratch),
 251                                 datalen);
 252                 break;
 253         default:
 254                 WARN_ON_ONCE(1);
 255                 return -EIO;
 256         }
 257         return err;
 258 }
 259
 260 static int logfs_read_segment(struct super_block *sb, u32 segno)
 261 {
 262         struct logfs_super *super = logfs_super(sb);
 263         struct logfs_journal_header *jh = super->s_compressed_je;
 264         u64 ofs, seg_ofs = dev_ofs(sb, segno, 0);
 265         u32 h_ofs, last_ofs = 0;
 266         u16 len, datalen, last_len = 0;
 267         int i, err;
 268
 269         /* search for most recent commit */
 270         for (h_ofs = 0; h_ofs < super->s_segsize; h_ofs += sizeof(*jh)) {
 271                 ofs = seg_ofs + h_ofs;
 272                 err = __read_je_header(sb, ofs, jh);
 273                 if (err)
 274                         continue;
 275                 if (jh->h_type != cpu_to_be16(JE_COMMIT))
 276                         continue;
 277                 err = __read_je_payload(sb, ofs, jh);
 278                 if (err)
 279                         continue;
 280                 len = be16_to_cpu(jh->h_len);
 281                 datalen = be16_to_cpu(jh->h_datalen);
 282                 if ((datalen > sizeof(super->s_je_array)) ||
 283                                 (datalen % sizeof(__be64)))
 284                         continue;
 285                 last_ofs = h_ofs;
 286                 last_len = datalen;
 287                 h_ofs += ALIGN(len, sizeof(*jh)) - sizeof(*jh);
 288         }
 289         /* read commit */
 290         if (last_ofs == 0)
 291                 return -ENOENT;
 292         ofs = seg_ofs + last_ofs;
 293         log_journal("Read commit from %llx\n", ofs);
 294         err = __read_je(sb, ofs, jh);
 295         BUG_ON(err); /* We should have caught it in the scan loop already */
 296         if (err)
 297                 return err;
 298         /* uncompress */
 299         unpack(jh, super->s_je_array);
 300         super->s_no_je = last_len / sizeof(__be64);
 301         /* iterate over array */
 302         for (i = 0; i < super->s_no_je; i++) {
 303                 err = read_je(sb, be64_to_cpu(super->s_je_array[i]));
 304                 if (err)
 305                         return err;
 306         }
 307         super->s_journal_area->a_segno = segno;
 308         return 0;
 309 }
 310
 311 static u64 read_gec(struct super_block *sb, u32 segno)
 312 {
 313         struct logfs_segment_header sh;
 314         __be32 crc;
 315         int err;
 316
 317         if (!segno)
 318                 return 0;
 319         err = wbuf_read(sb, dev_ofs(sb, segno, 0), sizeof(sh), &sh);
 320         if (err)
 321                 return 0;
 322         crc = logfs_crc32(&sh, sizeof(sh), 4);
 323         if (crc != sh.crc) {
 324                 WARN_ON(sh.gec != cpu_to_be64(0xffffffffffffffffull));
 325                 /* Most likely it was just erased */
 326                 return 0;
 327         }
 328         return be64_to_cpu(sh.gec);
 329 }
 330
 331 static int logfs_read_journal(struct super_block *sb)
 332 {
 333         struct logfs_super *super = logfs_super(sb);
 334         u64 gec[LOGFS_JOURNAL_SEGS], max;
 335         u32 segno;
 336         int i, max_i;
 337
 338         max = 0;
 339         max_i = -1;
 340         journal_for_each(i) {
 341                 segno = super->s_journal_seg[i];
 342                 gec[i] = read_gec(sb, super->s_journal_seg[i]);
 343                 if (gec[i] > max) {
 344                         max = gec[i];
 345                         max_i = i;
 346                 }
 347         }
 348         if (max_i == -1)
 349                 return -EIO;
 350         /* FIXME: Try older segments in case of error */
 351         return logfs_read_segment(sb, super->s_journal_seg[max_i]);
 352 }
 353
 354 /*
 355  * First search the current segment (outer loop), then pick the next segment
 356  * in the array, skipping any zero entries (inner loop).
 357  */
 358 static void journal_get_free_segment(struct logfs_area *area)
 359 {
 360         struct logfs_super *super = logfs_super(area->a_sb);
 361         int i;
 362
 363         journal_for_each(i) {
 364                 if (area->a_segno != super->s_journal_seg[i])
 365                         continue;
 366
 367                 do {
 368                         i++;
 369                         if (i == LOGFS_JOURNAL_SEGS)
 370                                 i = 0;
 371                 } while (!super->s_journal_seg[i]);
 372
 373                 area->a_segno = super->s_journal_seg[i];
 374                 area->a_erase_count = ++(super->s_journal_ec[i]);
 375                 log_journal("Journal now at %x (ec %x)\n", area->a_segno,
 376                                 area->a_erase_count);
 377                 return;
 378         }
 379         BUG();
 380 }
 381
 382 static void journal_get_erase_count(struct logfs_area *area)
 383 {
 384         /* erase count is stored globally and incremented in
 385          * journal_get_free_segment() - nothing to do here */
 386 }
 387
 388 static int journal_erase_segment(struct logfs_area *area)
 389 {
 390         struct super_block *sb = area->a_sb;
 391         struct logfs_segment_header sh;
 392         u64 ofs;
 393         int err;
 394
 395         err = logfs_erase_segment(sb, area->a_segno, 1);
 396         if (err)
 397                 return err;
 398
 399         sh.pad = 0;
 400         sh.type = SEG_JOURNAL;
 401         sh.level = 0;
 402         sh.segno = cpu_to_be32(area->a_segno);
 403         sh.ec = cpu_to_be32(area->a_erase_count);
 404         sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
 405         sh.crc = logfs_crc32(&sh, sizeof(sh), 4);
 406
 407         /* This causes a bug in segment.c.  Not yet. */
 408         //logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, 0);
 409
 410         ofs = dev_ofs(sb, area->a_segno, 0);
 411         area->a_used_bytes = ALIGN(sizeof(sh), 16);
 412         logfs_buf_write(area, ofs, &sh, sizeof(sh));
 413         return 0;
 414 }
 415
 416 static size_t __logfs_write_header(struct logfs_super *super,
 417                 struct logfs_journal_header *jh, size_t len, size_t datalen,
 418                 u16 type, u8 compr)
 419 {
 420         jh->h_len       = cpu_to_be16(len);
 421         jh->h_type      = cpu_to_be16(type);
 422         jh->h_datalen   = cpu_to_be16(datalen);
 423         jh->h_compr     = compr;
 424         jh->h_pad[0]    = 'H';
 425         jh->h_pad[1]    = 'E';
 426         jh->h_pad[2]    = 'A';
 427         jh->h_pad[3]    = 'D';
 428         jh->h_pad[4]    = 'R';
 429         jh->h_crc       = logfs_crc32(jh, len + sizeof(*jh), 4);
 430         return ALIGN(len, 16) + sizeof(*jh);
 431 }
 432
 433 static size_t logfs_write_header(struct logfs_super *super,
 434                 struct logfs_journal_header *jh, size_t datalen, u16 type)
 435 {
 436         size_t len = datalen;
 437
 438         return __logfs_write_header(super, jh, len, datalen, type, COMPR_NONE);
 439 }
 440
 441 static inline size_t logfs_journal_erasecount_size(struct logfs_super *super)
 442 {
 443         return LOGFS_JOURNAL_SEGS * sizeof(__be32);
 444 }
 445
 446 static void *logfs_write_erasecount(struct super_block *sb, void *_ec,
 447                 u16 *type, size_t *len)
 448 {
 449         struct logfs_super *super = logfs_super(sb);
 450         struct logfs_je_journal_ec *ec = _ec;
 451         int i;
 452
 453         journal_for_each(i)
 454                 ec->ec[i] = cpu_to_be32(super->s_journal_ec[i]);
 455         *type = JE_ERASECOUNT;
 456         *len = logfs_journal_erasecount_size(super);
 457         return ec;
 458 }
 459
 460 static void account_shadow(void *_shadow, unsigned long _sb, u64 ignore,
 461                 size_t ignore2)
 462 {
 463         struct logfs_shadow *shadow = _shadow;
 464         struct super_block *sb = (void *)_sb;
 465         struct logfs_super *super = logfs_super(sb);
 466
 467         /* consume new space */
 468         super->s_free_bytes       -= shadow->new_len;
 469         super->s_used_bytes       += shadow->new_len;
 470         super->s_dirty_used_bytes -= shadow->new_len;
 471
 472         /* free up old space */
 473         super->s_free_bytes       += shadow->old_len;
 474         super->s_used_bytes       -= shadow->old_len;
 475         super->s_dirty_free_bytes -= shadow->old_len;
 476
 477         logfs_set_segment_used(sb, shadow->old_ofs, -shadow->old_len);
 478         logfs_set_segment_used(sb, shadow->new_ofs, shadow->new_len);
 479
 480         log_journal("account_shadow(%llx, %llx, %x) %llx->%llx %x->%x\n",
 481                         shadow->ino, shadow->bix, shadow->gc_level,
 482                         shadow->old_ofs, shadow->new_ofs,
 483                         shadow->old_len, shadow->new_len);
 484         mempool_free(shadow, super->s_shadow_pool);
 485 }
 486
 487 static void account_shadows(struct super_block *sb)
 488 {
 489         struct logfs_super *super = logfs_super(sb);
 490         struct inode *inode = super->s_master_inode;
 491         struct logfs_inode *li = logfs_inode(inode);
 492         struct shadow_tree *tree = &super->s_shadow_tree;
 493
 494         btree_grim_visitor64(&tree->new, (unsigned long)sb, account_shadow);
 495         btree_grim_visitor64(&tree->old, (unsigned long)sb, account_shadow);
 496
 497         if (li->li_block) {
 498                 /*
 499                  * We never actually use the structure, when attached to the
 500                  * master inode.  But it is easier to always free it here than
 501                  * to have checks in several places elsewhere when allocating
 502                  * it.
 503                  */
 504                 li->li_block->ops->free_block(sb, li->li_block);
 505         }
 506         BUG_ON((s64)li->li_used_bytes < 0);
 507 }
 508
 509 static void *__logfs_write_anchor(struct super_block *sb, void *_da,
 510                 u16 *type, size_t *len)
 511 {
 512         struct logfs_super *super = logfs_super(sb);
 513         struct logfs_je_anchor *da = _da;
 514         struct inode *inode = super->s_master_inode;
 515         struct logfs_inode *li = logfs_inode(inode);
 516         int i;
 517
 518         da->da_height   = li->li_height;
 519         da->da_last_ino = cpu_to_be64(super->s_last_ino);
 520         da->da_size     = cpu_to_be64(i_size_read(inode));
 521         da->da_used_bytes = cpu_to_be64(li->li_used_bytes);
 522         for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 523                 da->da_data[i] = cpu_to_be64(li->li_data[i]);
 524         *type = JE_ANCHOR;
 525         *len = sizeof(*da);
 526         return da;
 527 }
 528
 529 static void *logfs_write_dynsb(struct super_block *sb, void *_dynsb,
 530                 u16 *type, size_t *len)
 531 {
 532         struct logfs_super *super = logfs_super(sb);
 533         struct logfs_je_dynsb *dynsb = _dynsb;
 534
 535         dynsb->ds_gec           = cpu_to_be64(super->s_gec);
 536         dynsb->ds_sweeper       = cpu_to_be64(super->s_sweeper);
 537         dynsb->ds_victim_ino    = cpu_to_be64(super->s_victim_ino);
 538         dynsb->ds_rename_dir    = cpu_to_be64(super->s_rename_dir);
 539         dynsb->ds_rename_pos    = cpu_to_be64(super->s_rename_pos);
 540         dynsb->ds_used_bytes    = cpu_to_be64(super->s_used_bytes);
 541         dynsb->ds_generation    = cpu_to_be32(super->s_generation);
 542         *type = JE_DYNSB;
 543         *len = sizeof(*dynsb);
 544         return dynsb;
 545 }
 546
 547 static void write_wbuf(struct super_block *sb, struct logfs_area *area,
 548                 void *wbuf)
 549 {
 550         struct logfs_super *super = logfs_super(sb);
 551         struct address_space *mapping = super->s_mapping_inode->i_mapping;
 552         u64 ofs;
 553         pgoff_t index;
 554         int page_ofs;
 555         struct page *page;
 556
 557         ofs = dev_ofs(sb, area->a_segno,
 558                         area->a_used_bytes & ~(super->s_writesize - 1));
 559         index = ofs >> PAGE_SHIFT;
 560         page_ofs = ofs & (PAGE_SIZE - 1);
 561
 562         page = find_lock_page(mapping, index);
 563         BUG_ON(!page);
 564         memcpy(wbuf, page_address(page) + page_ofs, super->s_writesize);
 565         unlock_page(page);
 566 }
 567
 568 static void *logfs_write_area(struct super_block *sb, void *_a,
 569                 u16 *type, size_t *len)
 570 {
 571         struct logfs_super *super = logfs_super(sb);
 572         struct logfs_area *area = super->s_area[super->s_sum_index];
 573         struct logfs_je_area *a = _a;
 574
 575         a->vim = VIM_DEFAULT;
 576         a->gc_level = super->s_sum_index;
 577         a->used_bytes = cpu_to_be32(area->a_used_bytes);
 578         a->segno = cpu_to_be32(area->a_segno);
 579         if (super->s_writesize > 1)
 580                 write_wbuf(sb, area, a + 1);
 581
 582         *type = JE_AREA;
 583         *len = sizeof(*a) + super->s_writesize;
 584         return a;
 585 }
 586
 587 static void *logfs_write_commit(struct super_block *sb, void *h,
 588                 u16 *type, size_t *len)
 589 {
 590         struct logfs_super *super = logfs_super(sb);
 591
 592         *type = JE_COMMIT;
 593         *len = super->s_no_je * sizeof(__be64);
 594         return super->s_je_array;
 595 }
 596
 597 static size_t __logfs_write_je(struct super_block *sb, void *buf, u16 type,
 598                 size_t len)
 599 {
 600         struct logfs_super *super = logfs_super(sb);
 601         void *header = super->s_compressed_je;
 602         void *data = header + sizeof(struct logfs_journal_header);
 603         ssize_t compr_len, pad_len;
 604         u8 compr = COMPR_ZLIB;
 605
 606         if (len == 0)
 607                 return logfs_write_header(super, header, 0, type);
 608
 609         compr_len = logfs_compress(buf, data, len, sb->s_blocksize);
 610         if (compr_len < 0 || type == JE_ANCHOR) {
 611                 BUG_ON(len > sb->s_blocksize);
 612                 memcpy(data, buf, len);
 613                 compr_len = len;
 614                 compr = COMPR_NONE;
 615         }
 616
 617         pad_len = ALIGN(compr_len, 16);
 618         memset(data + compr_len, 0, pad_len - compr_len);
 619
 620         return __logfs_write_header(super, header, compr_len, len, type, compr);
 621 }
 622
 623 static s64 logfs_get_free_bytes(struct logfs_area *area, size_t *bytes,
 624                 int must_pad)
 625 {
 626         u32 writesize = logfs_super(area->a_sb)->s_writesize;
 627         s32 ofs;
 628         int ret;
 629
 630         ret = logfs_open_area(area, *bytes);
 631         if (ret)
 632                 return -EAGAIN;
 633
 634         ofs = area->a_used_bytes;
 635         area->a_used_bytes += *bytes;
 636
 637         if (must_pad) {
 638                 area->a_used_bytes = ALIGN(area->a_used_bytes, writesize);
 639                 *bytes = area->a_used_bytes - ofs;
 640         }
 641
 642         return dev_ofs(area->a_sb, area->a_segno, ofs);
 643 }
 644
 645 static int logfs_write_je_buf(struct super_block *sb, void *buf, u16 type,
 646                 size_t buf_len)
 647 {
 648         struct logfs_super *super = logfs_super(sb);
 649         struct logfs_area *area = super->s_journal_area;
 650         struct logfs_journal_header *jh = super->s_compressed_je;
 651         size_t len;
 652         int must_pad = 0;
 653         s64 ofs;
 654
 655         len = __logfs_write_je(sb, buf, type, buf_len);
 656         if (jh->h_type == cpu_to_be16(JE_COMMIT))
 657                 must_pad = 1;
 658
 659         ofs = logfs_get_free_bytes(area, &len, must_pad);
 660         if (ofs < 0)
 661                 return ofs;
 662         logfs_buf_write(area, ofs, super->s_compressed_je, len);
 663         super->s_je_array[super->s_no_je++] = cpu_to_be64(ofs);
 664         return 0;
 665 }
 666
 667 static int logfs_write_je(struct super_block *sb,
 668                 void* (*write)(struct super_block *sb, void *scratch,
 669                         u16 *type, size_t *len))
 670 {
 671         void *buf;
 672         size_t len;
 673         u16 type;
 674
 675         buf = write(sb, logfs_super(sb)->s_je, &type, &len);
 676         return logfs_write_je_buf(sb, buf, type, len);
 677 }
 678
 679 int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,
 680                 level_t level, int child_no, __be64 val)
 681 {
 682         struct logfs_super *super = logfs_super(sb);
 683         struct logfs_obj_alias *oa = super->s_je;
 684         int err = 0, fill = super->s_je_fill;
 685
 686         log_aliases("logfs_write_obj_aliases #%x(%llx, %llx, %x, %x) %llx\n",
 687                         fill, ino, bix, level, child_no, be64_to_cpu(val));
 688         oa[fill].ino = cpu_to_be64(ino);
 689         oa[fill].bix = cpu_to_be64(bix);
 690         oa[fill].val = val;
 691         oa[fill].level = (__force u8)level;
 692         oa[fill].child_no = cpu_to_be16(child_no);
 693         fill++;
 694         if (fill >= sb->s_blocksize / sizeof(*oa)) {
 695                 err = logfs_write_je_buf(sb, oa, JE_OBJ_ALIAS, sb->s_blocksize);
 696                 fill = 0;
 697         }
 698
 699         super->s_je_fill = fill;
 700         return err;
 701 }
 702
 703 static int logfs_write_obj_aliases(struct super_block *sb)
 704 {
 705         struct logfs_super *super = logfs_super(sb);
 706         int err;
 707
 708         log_journal("logfs_write_obj_aliases: %d aliases to write\n",
 709                         super->s_no_object_aliases);
 710         super->s_je_fill = 0;
 711         err = logfs_write_obj_aliases_pagecache(sb);
 712         if (err)
 713                 return err;
 714
 715         if (super->s_je_fill)
 716                 err = logfs_write_je_buf(sb, super->s_je, JE_OBJ_ALIAS,
 717                                 super->s_je_fill
 718                                 * sizeof(struct logfs_obj_alias));
 719         return err;
 720 }
 721
 722 /*
 723  * Write all journal entries.  The goto logic ensures that all journal entries
 724  * are written whenever a new segment is used.  It is ugly and potentially a
 725  * bit wasteful, but robustness is more important.  With this we can *always*
 726  * erase all journal segments except the one containing the most recent commit.
 727  */
 728 void logfs_write_anchor(struct super_block *sb)
 729 {
 730         struct logfs_super *super = logfs_super(sb);
 731         struct logfs_area *area = super->s_journal_area;
 732         int i, err;
 733
 734         if (!(super->s_flags & LOGFS_SB_FLAG_DIRTY))
 735                 return;
 736         super->s_flags &= ~LOGFS_SB_FLAG_DIRTY;
 737
 738         BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
 739         mutex_lock(&super->s_journal_mutex);
 740
 741         /* Do this first or suffer corruption */
 742         logfs_sync_segments(sb);
 743         account_shadows(sb);
 744
 745 again:
 746         super->s_no_je = 0;
 747         for_each_area(i) {
 748                 if (!super->s_area[i]->a_is_open)
 749                         continue;
 750                 super->s_sum_index = i;
 751                 err = logfs_write_je(sb, logfs_write_area);
 752                 if (err)
 753                         goto again;
 754         }
 755         err = logfs_write_obj_aliases(sb);
 756         if (err)
 757                 goto again;
 758         err = logfs_write_je(sb, logfs_write_erasecount);
 759         if (err)
 760                 goto again;
 761         err = logfs_write_je(sb, __logfs_write_anchor);
 762         if (err)
 763                 goto again;
 764         err = logfs_write_je(sb, logfs_write_dynsb);
 765         if (err)
 766                 goto again;
 767         /*
 768          * Order is imperative.  First we sync all writes, including the
 769          * non-committed journal writes.  Then we write the final commit and
 770          * sync the current journal segment.
 771          * There is a theoretical bug here.  Syncing the journal segment will
 772          * write a number of journal entries and the final commit.  All these
 773          * are written in a single operation.  If the device layer writes the
 774          * data back-to-front, the commit will precede the other journal
 775          * entries, leaving a race window.
 776          * Two fixes are possible.  Preferred is to fix the device layer to
 777          * ensure writes happen front-to-back.  Alternatively we can insert
 778          * another logfs_sync_area() super->s_devops->sync() combo before
 779          * writing the commit.
 780          */
 781         /*
 782          * On another subject, super->s_devops->sync is usually not necessary.
 783          * Unless called from sys_sync or friends, a barrier would suffice.
 784          */
 785         super->s_devops->sync(sb);
 786         err = logfs_write_je(sb, logfs_write_commit);
 787         if (err)
 788                 goto again;
 789         log_journal("Write commit to %llx\n",
 790                         be64_to_cpu(super->s_je_array[super->s_no_je - 1]));
 791         logfs_sync_area(area);
 792         BUG_ON(area->a_used_bytes != area->a_written_bytes);
 793         super->s_devops->sync(sb);
 794
 795         mutex_unlock(&super->s_journal_mutex);
 796         return;
 797 }
 798
 799 void do_logfs_journal_wl_pass(struct super_block *sb)
 800 {
 801         struct logfs_super *super = logfs_super(sb);
 802         struct logfs_area *area = super->s_journal_area;
 803         u32 segno, ec;
 804         int i, err;
 805
 806         log_journal("Journal requires wear-leveling.\n");
 807         /* Drop old segments */
 808         journal_for_each(i)
 809                 if (super->s_journal_seg[i]) {
 810                         logfs_set_segment_unreserved(sb,
 811                                         super->s_journal_seg[i],
 812                                         super->s_journal_ec[i]);
 813                         super->s_journal_seg[i] = 0;
 814                         super->s_journal_ec[i] = 0;
 815                 }
 816         /* Get new segments */
 817         for (i = 0; i < super->s_no_journal_segs; i++) {
 818                 segno = get_best_cand(sb, &super->s_reserve_list, &ec);
 819                 super->s_journal_seg[i] = segno;
 820                 super->s_journal_ec[i] = ec;
 821                 logfs_set_segment_reserved(sb, segno);
 822         }
 823         /* Manually move journal_area */
 824         area->a_segno = super->s_journal_seg[0];
 825         area->a_is_open = 0;
 826         area->a_used_bytes = 0;
 827         /* Write journal */
 828         logfs_write_anchor(sb);
 829         /* Write superblocks */
 830         err = logfs_write_sb(sb);
 831         BUG_ON(err);
 832 }
 833
 834 static const struct logfs_area_ops journal_area_ops = {
 835         .get_free_segment       = journal_get_free_segment,
 836         .get_erase_count        = journal_get_erase_count,
 837         .erase_segment          = journal_erase_segment,
 838 };
 839
 840 int logfs_init_journal(struct super_block *sb)
 841 {
 842         struct logfs_super *super = logfs_super(sb);
 843         size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize)
 844                 + MAX_JOURNAL_HEADER;
 845         int ret = -ENOMEM;
 846
 847         mutex_init(&super->s_journal_mutex);
 848         btree_init_mempool32(&super->s_reserved_segments, super->s_btree_pool);
 849
 850         super->s_je = kzalloc(bufsize, GFP_KERNEL);
 851         if (!super->s_je)
 852                 return ret;
 853
 854         super->s_compressed_je = kzalloc(bufsize, GFP_KERNEL);
 855         if (!super->s_compressed_je)
 856                 return ret;
 857
 858         super->s_master_inode = logfs_new_meta_inode(sb, LOGFS_INO_MASTER);
 859         if (IS_ERR(super->s_master_inode))
 860                 return PTR_ERR(super->s_master_inode);
 861
 862         ret = logfs_read_journal(sb);
 863         if (ret)
 864                 return -EIO;
 865
 866         reserve_sb_and_journal(sb);
 867         logfs_calc_free(sb);
 868
 869         super->s_journal_area->a_ops = &journal_area_ops;
 870         return 0;
 871 }
 872
 873 void logfs_cleanup_journal(struct super_block *sb)
 874 {
 875         struct logfs_super *super = logfs_super(sb);
 876
 877         btree_grim_visitor32(&super->s_reserved_segments, 0, NULL);
 878         destroy_meta_inode(super->s_master_inode);
 879         super->s_master_inode = NULL;
 880
 881         kfree(super->s_compressed_je);
 882         kfree(super->s_je);
 883 }