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 #include <linux/slab.h>
  10
  11 static void logfs_calc_free(struct super_block *sb)
  12 {
  13         struct logfs_super *super = logfs_super(sb);
  14         u64 reserve, no_segs = super->s_no_segs;
  15         s64 free;
  16         int i;
  17
  18         /* superblock segments */
  19         no_segs -= 2;
  20         super->s_no_journal_segs = 0;
  21         /* journal */
  22         journal_for_each(i)
  23                 if (super->s_journal_seg[i]) {
  24                         no_segs--;
  25                         super->s_no_journal_segs++;
  26                 }
  27
  28         /* open segments plus one extra per level for GC */
  29         no_segs -= 2 * super->s_total_levels;
  30
  31         free = no_segs * (super->s_segsize - LOGFS_SEGMENT_RESERVE);
  32         free -= super->s_used_bytes;
  33         /* just a bit extra */
  34         free -= super->s_total_levels * 4096;
  35
  36         /* Bad blocks are 'paid' for with speed reserve - the filesystem
  37          * simply gets slower as bad blocks accumulate.  Until the bad blocks
  38          * exceed the speed reserve - then the filesystem gets smaller.
  39          */
  40         reserve = super->s_bad_segments + super->s_bad_seg_reserve;
  41         reserve *= super->s_segsize - LOGFS_SEGMENT_RESERVE;
  42         reserve = max(reserve, super->s_speed_reserve);
  43         free -= reserve;
  44         if (free < 0)
  45                 free = 0;
  46
  47         super->s_free_bytes = free;
  48 }
  49
  50 static void reserve_sb_and_journal(struct super_block *sb)
  51 {
  52         struct logfs_super *super = logfs_super(sb);
  53         struct btree_head32 *head = &super->s_reserved_segments;
  54         int i, err;
  55
  56         err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[0]), (void *)1,
  57                         GFP_KERNEL);
  58         BUG_ON(err);
  59
  60         err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[1]), (void *)1,
  61                         GFP_KERNEL);
  62         BUG_ON(err);
  63
  64         journal_for_each(i) {
  65                 if (!super->s_journal_seg[i])
  66                         continue;
  67                 err = btree_insert32(head, super->s_journal_seg[i], (void *)1,
  68                                 GFP_KERNEL);
  69                 BUG_ON(err);
  70         }
  71 }
  72
  73 static void read_dynsb(struct super_block *sb,
  74                 struct logfs_je_dynsb *dynsb)
  75 {
  76         struct logfs_super *super = logfs_super(sb);
  77
  78         super->s_gec            = be64_to_cpu(dynsb->ds_gec);
  79         super->s_sweeper        = be64_to_cpu(dynsb->ds_sweeper);
  80         super->s_victim_ino     = be64_to_cpu(dynsb->ds_victim_ino);
  81         super->s_rename_dir     = be64_to_cpu(dynsb->ds_rename_dir);
  82         super->s_rename_pos     = be64_to_cpu(dynsb->ds_rename_pos);
  83         super->s_used_bytes     = be64_to_cpu(dynsb->ds_used_bytes);
  84         super->s_generation     = be32_to_cpu(dynsb->ds_generation);
  85 }
  86
  87 static void read_anchor(struct super_block *sb,
  88                 struct logfs_je_anchor *da)
  89 {
  90         struct logfs_super *super = logfs_super(sb);
  91         struct inode *inode = super->s_master_inode;
  92         struct logfs_inode *li = logfs_inode(inode);
  93         int i;
  94
  95         super->s_last_ino = be64_to_cpu(da->da_last_ino);
  96         li->li_flags    = 0;
  97         li->li_height   = da->da_height;
  98         i_size_write(inode, be64_to_cpu(da->da_size));
  99         li->li_used_bytes = be64_to_cpu(da->da_used_bytes);
 100
 101         for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 102                 li->li_data[i] = be64_to_cpu(da->da_data[i]);
 103 }
 104
 105 static void read_erasecount(struct super_block *sb,
 106                 struct logfs_je_journal_ec *ec)
 107 {
 108         struct logfs_super *super = logfs_super(sb);
 109         int i;
 110
 111         journal_for_each(i)
 112                 super->s_journal_ec[i] = be32_to_cpu(ec->ec[i]);
 113 }
 114
 115 static int read_area(struct super_block *sb, struct logfs_je_area *a)
 116 {
 117         struct logfs_super *super = logfs_super(sb);
 118         struct logfs_area *area = super->s_area[a->gc_level];
 119         u64 ofs;
 120         u32 writemask = ~(super->s_writesize - 1);
 121
 122         if (a->gc_level >= LOGFS_NO_AREAS)
 123                 return -EIO;
 124         if (a->vim != VIM_DEFAULT)
 125                 return -EIO; /* TODO: close area and continue */
 126
 127         area->a_used_bytes = be32_to_cpu(a->used_bytes);
 128         area->a_written_bytes = area->a_used_bytes & writemask;
 129         area->a_segno = be32_to_cpu(a->segno);
 130         if (area->a_segno)
 131                 area->a_is_open = 1;
 132
 133         ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
 134         if (super->s_writesize > 1)
 135                 return logfs_buf_recover(area, ofs, a + 1, super->s_writesize);
 136         else
 137                 return logfs_buf_recover(area, ofs, NULL, 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                 err = 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         union {
 392                 struct logfs_segment_header sh;
 393                 unsigned char c[ALIGN(sizeof(struct logfs_segment_header), 16)];
 394         } u;
 395         u64 ofs;
 396         int err;
 397
 398         err = logfs_erase_segment(sb, area->a_segno, 1);
 399         if (err)
 400                 return err;
 401
 402         memset(&u, 0, sizeof(u));
 403         u.sh.pad = 0;
 404         u.sh.type = SEG_JOURNAL;
 405         u.sh.level = 0;
 406         u.sh.segno = cpu_to_be32(area->a_segno);
 407         u.sh.ec = cpu_to_be32(area->a_erase_count);
 408         u.sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
 409         u.sh.crc = logfs_crc32(&u.sh, sizeof(u.sh), 4);
 410
 411         /* This causes a bug in segment.c.  Not yet. */
 412         //logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, 0);
 413
 414         ofs = dev_ofs(sb, area->a_segno, 0);
 415         area->a_used_bytes = sizeof(u);
 416         logfs_buf_write(area, ofs, &u, sizeof(u));
 417         return 0;
 418 }
 419
 420 static size_t __logfs_write_header(struct logfs_super *super,
 421                 struct logfs_journal_header *jh, size_t len, size_t datalen,
 422                 u16 type, u8 compr)
 423 {
 424         jh->h_len       = cpu_to_be16(len);
 425         jh->h_type      = cpu_to_be16(type);
 426         jh->h_datalen   = cpu_to_be16(datalen);
 427         jh->h_compr     = compr;
 428         jh->h_pad[0]    = 'H';
 429         jh->h_pad[1]    = 'E';
 430         jh->h_pad[2]    = 'A';
 431         jh->h_pad[3]    = 'D';
 432         jh->h_pad[4]    = 'R';
 433         jh->h_crc       = logfs_crc32(jh, len + sizeof(*jh), 4);
 434         return ALIGN(len, 16) + sizeof(*jh);
 435 }
 436
 437 static size_t logfs_write_header(struct logfs_super *super,
 438                 struct logfs_journal_header *jh, size_t datalen, u16 type)
 439 {
 440         size_t len = datalen;
 441
 442         return __logfs_write_header(super, jh, len, datalen, type, COMPR_NONE);
 443 }
 444
 445 static inline size_t logfs_journal_erasecount_size(struct logfs_super *super)
 446 {
 447         return LOGFS_JOURNAL_SEGS * sizeof(__be32);
 448 }
 449
 450 static void *logfs_write_erasecount(struct super_block *sb, void *_ec,
 451                 u16 *type, size_t *len)
 452 {
 453         struct logfs_super *super = logfs_super(sb);
 454         struct logfs_je_journal_ec *ec = _ec;
 455         int i;
 456
 457         journal_for_each(i)
 458                 ec->ec[i] = cpu_to_be32(super->s_journal_ec[i]);
 459         *type = JE_ERASECOUNT;
 460         *len = logfs_journal_erasecount_size(super);
 461         return ec;
 462 }
 463
 464 static void account_shadow(void *_shadow, unsigned long _sb, u64 ignore,
 465                 size_t ignore2)
 466 {
 467         struct logfs_shadow *shadow = _shadow;
 468         struct super_block *sb = (void *)_sb;
 469         struct logfs_super *super = logfs_super(sb);
 470
 471         /* consume new space */
 472         super->s_free_bytes       -= shadow->new_len;
 473         super->s_used_bytes       += shadow->new_len;
 474         super->s_dirty_used_bytes -= shadow->new_len;
 475
 476         /* free up old space */
 477         super->s_free_bytes       += shadow->old_len;
 478         super->s_used_bytes       -= shadow->old_len;
 479         super->s_dirty_free_bytes -= shadow->old_len;
 480
 481         logfs_set_segment_used(sb, shadow->old_ofs, -shadow->old_len);
 482         logfs_set_segment_used(sb, shadow->new_ofs, shadow->new_len);
 483
 484         log_journal("account_shadow(%llx, %llx, %x) %llx->%llx %x->%x\n",
 485                         shadow->ino, shadow->bix, shadow->gc_level,
 486                         shadow->old_ofs, shadow->new_ofs,
 487                         shadow->old_len, shadow->new_len);
 488         mempool_free(shadow, super->s_shadow_pool);
 489 }
 490
 491 static void account_shadows(struct super_block *sb)
 492 {
 493         struct logfs_super *super = logfs_super(sb);
 494         struct inode *inode = super->s_master_inode;
 495         struct logfs_inode *li = logfs_inode(inode);
 496         struct shadow_tree *tree = &super->s_shadow_tree;
 497
 498         btree_grim_visitor64(&tree->new, (unsigned long)sb, account_shadow);
 499         btree_grim_visitor64(&tree->old, (unsigned long)sb, account_shadow);
 500         btree_grim_visitor32(&tree->segment_map, 0, NULL);
 501         tree->no_shadowed_segments = 0;
 502
 503         if (li->li_block) {
 504                 /*
 505                  * We never actually use the structure, when attached to the
 506                  * master inode.  But it is easier to always free it here than
 507                  * to have checks in several places elsewhere when allocating
 508                  * it.
 509                  */
 510                 li->li_block->ops->free_block(sb, li->li_block);
 511         }
 512         BUG_ON((s64)li->li_used_bytes < 0);
 513 }
 514
 515 static void *__logfs_write_anchor(struct super_block *sb, void *_da,
 516                 u16 *type, size_t *len)
 517 {
 518         struct logfs_super *super = logfs_super(sb);
 519         struct logfs_je_anchor *da = _da;
 520         struct inode *inode = super->s_master_inode;
 521         struct logfs_inode *li = logfs_inode(inode);
 522         int i;
 523
 524         da->da_height   = li->li_height;
 525         da->da_last_ino = cpu_to_be64(super->s_last_ino);
 526         da->da_size     = cpu_to_be64(i_size_read(inode));
 527         da->da_used_bytes = cpu_to_be64(li->li_used_bytes);
 528         for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 529                 da->da_data[i] = cpu_to_be64(li->li_data[i]);
 530         *type = JE_ANCHOR;
 531         *len = sizeof(*da);
 532         return da;
 533 }
 534
 535 static void *logfs_write_dynsb(struct super_block *sb, void *_dynsb,
 536                 u16 *type, size_t *len)
 537 {
 538         struct logfs_super *super = logfs_super(sb);
 539         struct logfs_je_dynsb *dynsb = _dynsb;
 540
 541         dynsb->ds_gec           = cpu_to_be64(super->s_gec);
 542         dynsb->ds_sweeper       = cpu_to_be64(super->s_sweeper);
 543         dynsb->ds_victim_ino    = cpu_to_be64(super->s_victim_ino);
 544         dynsb->ds_rename_dir    = cpu_to_be64(super->s_rename_dir);
 545         dynsb->ds_rename_pos    = cpu_to_be64(super->s_rename_pos);
 546         dynsb->ds_used_bytes    = cpu_to_be64(super->s_used_bytes);
 547         dynsb->ds_generation    = cpu_to_be32(super->s_generation);
 548         *type = JE_DYNSB;
 549         *len = sizeof(*dynsb);
 550         return dynsb;
 551 }
 552
 553 static void write_wbuf(struct super_block *sb, struct logfs_area *area,
 554                 void *wbuf)
 555 {
 556         struct logfs_super *super = logfs_super(sb);
 557         struct address_space *mapping = super->s_mapping_inode->i_mapping;
 558         u64 ofs;
 559         pgoff_t index;
 560         int page_ofs;
 561         struct page *page;
 562
 563         ofs = dev_ofs(sb, area->a_segno,
 564                         area->a_used_bytes & ~(super->s_writesize - 1));
 565         index = ofs >> PAGE_SHIFT;
 566         page_ofs = ofs & (PAGE_SIZE - 1);
 567
 568         page = find_lock_page(mapping, index);
 569         BUG_ON(!page);
 570         memcpy(wbuf, page_address(page) + page_ofs, super->s_writesize);
 571         unlock_page(page);
 572 }
 573
 574 static void *logfs_write_area(struct super_block *sb, void *_a,
 575                 u16 *type, size_t *len)
 576 {
 577         struct logfs_super *super = logfs_super(sb);
 578         struct logfs_area *area = super->s_area[super->s_sum_index];
 579         struct logfs_je_area *a = _a;
 580
 581         a->vim = VIM_DEFAULT;
 582         a->gc_level = super->s_sum_index;
 583         a->used_bytes = cpu_to_be32(area->a_used_bytes);
 584         a->segno = cpu_to_be32(area->a_segno);
 585         if (super->s_writesize > 1)
 586                 write_wbuf(sb, area, a + 1);
 587
 588         *type = JE_AREA;
 589         *len = sizeof(*a) + super->s_writesize;
 590         return a;
 591 }
 592
 593 static void *logfs_write_commit(struct super_block *sb, void *h,
 594                 u16 *type, size_t *len)
 595 {
 596         struct logfs_super *super = logfs_super(sb);
 597
 598         *type = JE_COMMIT;
 599         *len = super->s_no_je * sizeof(__be64);
 600         return super->s_je_array;
 601 }
 602
 603 static size_t __logfs_write_je(struct super_block *sb, void *buf, u16 type,
 604                 size_t len)
 605 {
 606         struct logfs_super *super = logfs_super(sb);
 607         void *header = super->s_compressed_je;
 608         void *data = header + sizeof(struct logfs_journal_header);
 609         ssize_t compr_len, pad_len;
 610         u8 compr = COMPR_ZLIB;
 611
 612         if (len == 0)
 613                 return logfs_write_header(super, header, 0, type);
 614
 615         BUG_ON(len > sb->s_blocksize);
 616         compr_len = logfs_compress(buf, data, len, sb->s_blocksize);
 617         if (compr_len < 0 || type == JE_ANCHOR) {
 618                 memcpy(data, buf, len);
 619                 compr_len = len;
 620                 compr = COMPR_NONE;
 621         }
 622
 623         pad_len = ALIGN(compr_len, 16);
 624         memset(data + compr_len, 0, pad_len - compr_len);
 625
 626         return __logfs_write_header(super, header, compr_len, len, type, compr);
 627 }
 628
 629 static s64 logfs_get_free_bytes(struct logfs_area *area, size_t *bytes,
 630                 int must_pad)
 631 {
 632         u32 writesize = logfs_super(area->a_sb)->s_writesize;
 633         s32 ofs;
 634         int ret;
 635
 636         ret = logfs_open_area(area, *bytes);
 637         if (ret)
 638                 return -EAGAIN;
 639
 640         ofs = area->a_used_bytes;
 641         area->a_used_bytes += *bytes;
 642
 643         if (must_pad) {
 644                 area->a_used_bytes = ALIGN(area->a_used_bytes, writesize);
 645                 *bytes = area->a_used_bytes - ofs;
 646         }
 647
 648         return dev_ofs(area->a_sb, area->a_segno, ofs);
 649 }
 650
 651 static int logfs_write_je_buf(struct super_block *sb, void *buf, u16 type,
 652                 size_t buf_len)
 653 {
 654         struct logfs_super *super = logfs_super(sb);
 655         struct logfs_area *area = super->s_journal_area;
 656         struct logfs_journal_header *jh = super->s_compressed_je;
 657         size_t len;
 658         int must_pad = 0;
 659         s64 ofs;
 660
 661         len = __logfs_write_je(sb, buf, type, buf_len);
 662         if (jh->h_type == cpu_to_be16(JE_COMMIT))
 663                 must_pad = 1;
 664
 665         ofs = logfs_get_free_bytes(area, &len, must_pad);
 666         if (ofs < 0)
 667                 return ofs;
 668         logfs_buf_write(area, ofs, super->s_compressed_je, len);
 669         BUG_ON(super->s_no_je >= MAX_JOURNAL_ENTRIES);
 670         super->s_je_array[super->s_no_je++] = cpu_to_be64(ofs);
 671         return 0;
 672 }
 673
 674 static int logfs_write_je(struct super_block *sb,
 675                 void* (*write)(struct super_block *sb, void *scratch,
 676                         u16 *type, size_t *len))
 677 {
 678         void *buf;
 679         size_t len;
 680         u16 type;
 681
 682         buf = write(sb, logfs_super(sb)->s_je, &type, &len);
 683         return logfs_write_je_buf(sb, buf, type, len);
 684 }
 685
 686 int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,
 687                 level_t level, int child_no, __be64 val)
 688 {
 689         struct logfs_super *super = logfs_super(sb);
 690         struct logfs_obj_alias *oa = super->s_je;
 691         int err = 0, fill = super->s_je_fill;
 692
 693         log_aliases("logfs_write_obj_aliases #%x(%llx, %llx, %x, %x) %llx\n",
 694                         fill, ino, bix, level, child_no, be64_to_cpu(val));
 695         oa[fill].ino = cpu_to_be64(ino);
 696         oa[fill].bix = cpu_to_be64(bix);
 697         oa[fill].val = val;
 698         oa[fill].level = (__force u8)level;
 699         oa[fill].child_no = cpu_to_be16(child_no);
 700         fill++;
 701         if (fill >= sb->s_blocksize / sizeof(*oa)) {
 702                 err = logfs_write_je_buf(sb, oa, JE_OBJ_ALIAS, sb->s_blocksize);
 703                 fill = 0;
 704         }
 705
 706         super->s_je_fill = fill;
 707         return err;
 708 }
 709
 710 static int logfs_write_obj_aliases(struct super_block *sb)
 711 {
 712         struct logfs_super *super = logfs_super(sb);
 713         int err;
 714
 715         log_journal("logfs_write_obj_aliases: %d aliases to write\n",
 716                         super->s_no_object_aliases);
 717         super->s_je_fill = 0;
 718         err = logfs_write_obj_aliases_pagecache(sb);
 719         if (err)
 720                 return err;
 721
 722         if (super->s_je_fill)
 723                 err = logfs_write_je_buf(sb, super->s_je, JE_OBJ_ALIAS,
 724                                 super->s_je_fill
 725                                 * sizeof(struct logfs_obj_alias));
 726         return err;
 727 }
 728
 729 /*
 730  * Write all journal entries.  The goto logic ensures that all journal entries
 731  * are written whenever a new segment is used.  It is ugly and potentially a
 732  * bit wasteful, but robustness is more important.  With this we can *always*
 733  * erase all journal segments except the one containing the most recent commit.
 734  */
 735 void logfs_write_anchor(struct super_block *sb)
 736 {
 737         struct logfs_super *super = logfs_super(sb);
 738         struct logfs_area *area = super->s_journal_area;
 739         int i, err;
 740
 741         if (!(super->s_flags & LOGFS_SB_FLAG_DIRTY))
 742                 return;
 743         super->s_flags &= ~LOGFS_SB_FLAG_DIRTY;
 744
 745         BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
 746         mutex_lock(&super->s_journal_mutex);
 747
 748         /* Do this first or suffer corruption */
 749         logfs_sync_segments(sb);
 750         account_shadows(sb);
 751
 752 again:
 753         super->s_no_je = 0;
 754         for_each_area(i) {
 755                 if (!super->s_area[i]->a_is_open)
 756                         continue;
 757                 super->s_sum_index = i;
 758                 err = logfs_write_je(sb, logfs_write_area);
 759                 if (err)
 760                         goto again;
 761         }
 762         err = logfs_write_obj_aliases(sb);
 763         if (err)
 764                 goto again;
 765         err = logfs_write_je(sb, logfs_write_erasecount);
 766         if (err)
 767                 goto again;
 768         err = logfs_write_je(sb, __logfs_write_anchor);
 769         if (err)
 770                 goto again;
 771         err = logfs_write_je(sb, logfs_write_dynsb);
 772         if (err)
 773                 goto again;
 774         /*
 775          * Order is imperative.  First we sync all writes, including the
 776          * non-committed journal writes.  Then we write the final commit and
 777          * sync the current journal segment.
 778          * There is a theoretical bug here.  Syncing the journal segment will
 779          * write a number of journal entries and the final commit.  All these
 780          * are written in a single operation.  If the device layer writes the
 781          * data back-to-front, the commit will precede the other journal
 782          * entries, leaving a race window.
 783          * Two fixes are possible.  Preferred is to fix the device layer to
 784          * ensure writes happen front-to-back.  Alternatively we can insert
 785          * another logfs_sync_area() super->s_devops->sync() combo before
 786          * writing the commit.
 787          */
 788         /*
 789          * On another subject, super->s_devops->sync is usually not necessary.
 790          * Unless called from sys_sync or friends, a barrier would suffice.
 791          */
 792         super->s_devops->sync(sb);
 793         err = logfs_write_je(sb, logfs_write_commit);
 794         if (err)
 795                 goto again;
 796         log_journal("Write commit to %llx\n",
 797                         be64_to_cpu(super->s_je_array[super->s_no_je - 1]));
 798         logfs_sync_area(area);
 799         BUG_ON(area->a_used_bytes != area->a_written_bytes);
 800         super->s_devops->sync(sb);
 801
 802         mutex_unlock(&super->s_journal_mutex);
 803         return;
 804 }
 805
 806 void do_logfs_journal_wl_pass(struct super_block *sb)
 807 {
 808         struct logfs_super *super = logfs_super(sb);
 809         struct logfs_area *area = super->s_journal_area;
 810         struct btree_head32 *head = &super->s_reserved_segments;
 811         u32 segno, ec;
 812         int i, err;
 813
 814         log_journal("Journal requires wear-leveling.\n");
 815         /* Drop old segments */
 816         journal_for_each(i)
 817                 if (super->s_journal_seg[i]) {
 818                         btree_remove32(head, super->s_journal_seg[i]);
 819                         logfs_set_segment_unreserved(sb,
 820                                         super->s_journal_seg[i],
 821                                         super->s_journal_ec[i]);
 822                         super->s_journal_seg[i] = 0;
 823                         super->s_journal_ec[i] = 0;
 824                 }
 825         /* Get new segments */
 826         for (i = 0; i < super->s_no_journal_segs; i++) {
 827                 segno = get_best_cand(sb, &super->s_reserve_list, &ec);
 828                 super->s_journal_seg[i] = segno;
 829                 super->s_journal_ec[i] = ec;
 830                 logfs_set_segment_reserved(sb, segno);
 831                 err = btree_insert32(head, segno, (void *)1, GFP_KERNEL);
 832                 BUG_ON(err); /* mempool should prevent this */
 833                 err = logfs_erase_segment(sb, segno, 1);
 834                 BUG_ON(err); /* FIXME: remount-ro would be nicer */
 835         }
 836         /* Manually move journal_area */
 837         freeseg(sb, area->a_segno);
 838         area->a_segno = super->s_journal_seg[0];
 839         area->a_is_open = 0;
 840         area->a_used_bytes = 0;
 841         /* Write journal */
 842         logfs_write_anchor(sb);
 843         /* Write superblocks */
 844         err = logfs_write_sb(sb);
 845         BUG_ON(err);
 846 }
 847
 848 static const struct logfs_area_ops journal_area_ops = {
 849         .get_free_segment       = journal_get_free_segment,
 850         .get_erase_count        = journal_get_erase_count,
 851         .erase_segment          = journal_erase_segment,
 852 };
 853
 854 int logfs_init_journal(struct super_block *sb)
 855 {
 856         struct logfs_super *super = logfs_super(sb);
 857         size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize)
 858                 + MAX_JOURNAL_HEADER;
 859         int ret = -ENOMEM;
 860
 861         mutex_init(&super->s_journal_mutex);
 862         btree_init_mempool32(&super->s_reserved_segments, super->s_btree_pool);
 863
 864         super->s_je = kzalloc(bufsize, GFP_KERNEL);
 865         if (!super->s_je)
 866                 return ret;
 867
 868         super->s_compressed_je = kzalloc(bufsize, GFP_KERNEL);
 869         if (!super->s_compressed_je)
 870                 return ret;
 871
 872         super->s_master_inode = logfs_new_meta_inode(sb, LOGFS_INO_MASTER);
 873         if (IS_ERR(super->s_master_inode))
 874                 return PTR_ERR(super->s_master_inode);
 875
 876         ret = logfs_read_journal(sb);
 877         if (ret)
 878                 return -EIO;
 879
 880         reserve_sb_and_journal(sb);
 881         logfs_calc_free(sb);
 882
 883         super->s_journal_area->a_ops = &journal_area_ops;
 884         return 0;
 885 }
 886
 887 void logfs_cleanup_journal(struct super_block *sb)
 888 {
 889         struct logfs_super *super = logfs_super(sb);
 890
 891         btree_grim_visitor32(&super->s_reserved_segments, 0, NULL);
 892
 893         kfree(super->s_compressed_je);
 894         kfree(super->s_je);
 895 }