fs/logfs/readwrite.c

   1 /*
   2  * fs/logfs/readwrite.c
   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  *
   9  * Actually contains five sets of very similar functions:
  10  * read         read blocks from a file
  11  * seek_hole    find next hole
  12  * seek_data    find next data block
  13  * valid        check whether a block still belongs to a file
  14  * write        write blocks to a file
  15  * delete       delete a block (for directories and ifile)
  16  * rewrite      move existing blocks of a file to a new location (gc helper)
  17  * truncate     truncate a file
  18  */
  19 #include "logfs.h"
  20 #include <linux/sched.h>
  21
  22 static u64 adjust_bix(u64 bix, level_t level)
  23 {
  24         switch (level) {
  25         case 0:
  26                 return bix;
  27         case LEVEL(1):
  28                 return max_t(u64, bix, I0_BLOCKS);
  29         case LEVEL(2):
  30                 return max_t(u64, bix, I1_BLOCKS);
  31         case LEVEL(3):
  32                 return max_t(u64, bix, I2_BLOCKS);
  33         case LEVEL(4):
  34                 return max_t(u64, bix, I3_BLOCKS);
  35         case LEVEL(5):
  36                 return max_t(u64, bix, I4_BLOCKS);
  37         default:
  38                 WARN_ON(1);
  39                 return bix;
  40         }
  41 }
  42
  43 static inline u64 maxbix(u8 height)
  44 {
  45         return 1ULL << (LOGFS_BLOCK_BITS * height);
  46 }
  47
  48 /**
  49  * The inode address space is cut in two halves.  Lower half belongs to data
  50  * pages, upper half to indirect blocks.  If the high bit (INDIRECT_BIT) is
  51  * set, the actual block index (bix) and level can be derived from the page
  52  * index.
  53  *
  54  * The lowest three bits of the block index are set to 0 after packing and
  55  * unpacking.  Since the lowest n bits (9 for 4KiB blocksize) are ignored
  56  * anyway this is harmless.
  57  */
  58 #define ARCH_SHIFT      (BITS_PER_LONG - 32)
  59 #define INDIRECT_BIT    (0x80000000UL << ARCH_SHIFT)
  60 #define LEVEL_SHIFT     (28 + ARCH_SHIFT)
  61 static inline pgoff_t first_indirect_block(void)
  62 {
  63         return INDIRECT_BIT | (1ULL << LEVEL_SHIFT);
  64 }
  65
  66 pgoff_t logfs_pack_index(u64 bix, level_t level)
  67 {
  68         pgoff_t index;
  69
  70         BUG_ON(bix >= INDIRECT_BIT);
  71         if (level == 0)
  72                 return bix;
  73
  74         index  = INDIRECT_BIT;
  75         index |= (__force long)level << LEVEL_SHIFT;
  76         index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS);
  77         return index;
  78 }
  79
  80 void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level)
  81 {
  82         u8 __level;
  83
  84         if (!(index & INDIRECT_BIT)) {
  85                 *bix = index;
  86                 *level = 0;
  87                 return;
  88         }
  89
  90         __level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT;
  91         *level = LEVEL(__level);
  92         *bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT;
  93         *bix = adjust_bix(*bix, *level);
  94         return;
  95 }
  96 #undef ARCH_SHIFT
  97 #undef INDIRECT_BIT
  98 #undef LEVEL_SHIFT
  99
 100 /*
 101  * Time is stored as nanoseconds since the epoch.
 102  */
 103 static struct timespec be64_to_timespec(__be64 betime)
 104 {
 105         return ns_to_timespec(be64_to_cpu(betime));
 106 }
 107
 108 static __be64 timespec_to_be64(struct timespec tsp)
 109 {
 110         return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec);
 111 }
 112
 113 static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode)
 114 {
 115         struct logfs_inode *li = logfs_inode(inode);
 116         int i;
 117
 118         inode->i_mode   = be16_to_cpu(di->di_mode);
 119         li->li_height   = di->di_height;
 120         li->li_flags    = be32_to_cpu(di->di_flags);
 121         inode->i_uid    = be32_to_cpu(di->di_uid);
 122         inode->i_gid    = be32_to_cpu(di->di_gid);
 123         inode->i_size   = be64_to_cpu(di->di_size);
 124         logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes));
 125         inode->i_atime  = be64_to_timespec(di->di_atime);
 126         inode->i_ctime  = be64_to_timespec(di->di_ctime);
 127         inode->i_mtime  = be64_to_timespec(di->di_mtime);
 128         inode->i_nlink  = be32_to_cpu(di->di_refcount);
 129         inode->i_generation = be32_to_cpu(di->di_generation);
 130
 131         switch (inode->i_mode & S_IFMT) {
 132         case S_IFSOCK:  /* fall through */
 133         case S_IFBLK:   /* fall through */
 134         case S_IFCHR:   /* fall through */
 135         case S_IFIFO:
 136                 inode->i_rdev = be64_to_cpu(di->di_data[0]);
 137                 break;
 138         case S_IFDIR:   /* fall through */
 139         case S_IFREG:   /* fall through */
 140         case S_IFLNK:
 141                 for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 142                         li->li_data[i] = be64_to_cpu(di->di_data[i]);
 143                 break;
 144         default:
 145                 BUG();
 146         }
 147 }
 148
 149 static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di)
 150 {
 151         struct logfs_inode *li = logfs_inode(inode);
 152         int i;
 153
 154         di->di_mode     = cpu_to_be16(inode->i_mode);
 155         di->di_height   = li->li_height;
 156         di->di_pad      = 0;
 157         di->di_flags    = cpu_to_be32(li->li_flags);
 158         di->di_uid      = cpu_to_be32(inode->i_uid);
 159         di->di_gid      = cpu_to_be32(inode->i_gid);
 160         di->di_size     = cpu_to_be64(i_size_read(inode));
 161         di->di_used_bytes = cpu_to_be64(li->li_used_bytes);
 162         di->di_atime    = timespec_to_be64(inode->i_atime);
 163         di->di_ctime    = timespec_to_be64(inode->i_ctime);
 164         di->di_mtime    = timespec_to_be64(inode->i_mtime);
 165         di->di_refcount = cpu_to_be32(inode->i_nlink);
 166         di->di_generation = cpu_to_be32(inode->i_generation);
 167
 168         switch (inode->i_mode & S_IFMT) {
 169         case S_IFSOCK:  /* fall through */
 170         case S_IFBLK:   /* fall through */
 171         case S_IFCHR:   /* fall through */
 172         case S_IFIFO:
 173                 di->di_data[0] = cpu_to_be64(inode->i_rdev);
 174                 break;
 175         case S_IFDIR:   /* fall through */
 176         case S_IFREG:   /* fall through */
 177         case S_IFLNK:
 178                 for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
 179                         di->di_data[i] = cpu_to_be64(li->li_data[i]);
 180                 break;
 181         default:
 182                 BUG();
 183         }
 184 }
 185
 186 static void __logfs_set_blocks(struct inode *inode)
 187 {
 188         struct super_block *sb = inode->i_sb;
 189         struct logfs_inode *li = logfs_inode(inode);
 190
 191         inode->i_blocks = ULONG_MAX;
 192         if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX)
 193                 inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9;
 194 }
 195
 196 void logfs_set_blocks(struct inode *inode, u64 bytes)
 197 {
 198         struct logfs_inode *li = logfs_inode(inode);
 199
 200         li->li_used_bytes = bytes;
 201         __logfs_set_blocks(inode);
 202 }
 203
 204 static void prelock_page(struct super_block *sb, struct page *page, int lock)
 205 {
 206         struct logfs_super *super = logfs_super(sb);
 207
 208         BUG_ON(!PageLocked(page));
 209         if (lock) {
 210                 BUG_ON(PagePreLocked(page));
 211                 SetPagePreLocked(page);
 212         } else {
 213                 /* We are in GC path. */
 214                 if (PagePreLocked(page))
 215                         super->s_lock_count++;
 216                 else
 217                         SetPagePreLocked(page);
 218         }
 219 }
 220
 221 static void preunlock_page(struct super_block *sb, struct page *page, int lock)
 222 {
 223         struct logfs_super *super = logfs_super(sb);
 224
 225         BUG_ON(!PageLocked(page));
 226         if (lock)
 227                 ClearPagePreLocked(page);
 228         else {
 229                 /* We are in GC path. */
 230                 BUG_ON(!PagePreLocked(page));
 231                 if (super->s_lock_count)
 232                         super->s_lock_count--;
 233                 else
 234                         ClearPagePreLocked(page);
 235         }
 236 }
 237
 238 /*
 239  * Logfs is prone to an AB-BA deadlock where one task tries to acquire
 240  * s_write_mutex with a locked page and GC tries to get that page while holding
 241  * s_write_mutex.
 242  * To solve this issue logfs will ignore the page lock iff the page in question
 243  * is waiting for s_write_mutex.  We annotate this fact by setting PG_pre_locked
 244  * in addition to PG_locked.
 245  */
 246 static void logfs_get_wblocks(struct super_block *sb, struct page *page,
 247                 int lock)
 248 {
 249         struct logfs_super *super = logfs_super(sb);
 250
 251         if (page)
 252                 prelock_page(sb, page, lock);
 253
 254         if (lock) {
 255                 mutex_lock(&super->s_write_mutex);
 256                 logfs_gc_pass(sb);
 257                 /* FIXME: We also have to check for shadowed space
 258                  * and mempool fill grade */
 259         }
 260 }
 261
 262 static void logfs_put_wblocks(struct super_block *sb, struct page *page,
 263                 int lock)
 264 {
 265         struct logfs_super *super = logfs_super(sb);
 266
 267         if (page)
 268                 preunlock_page(sb, page, lock);
 269         /* Order matters - we must clear PG_pre_locked before releasing
 270          * s_write_mutex or we could race against another task. */
 271         if (lock)
 272                 mutex_unlock(&super->s_write_mutex);
 273 }
 274
 275 static struct page *logfs_get_read_page(struct inode *inode, u64 bix,
 276                 level_t level)
 277 {
 278         return find_or_create_page(inode->i_mapping,
 279                         logfs_pack_index(bix, level), GFP_NOFS);
 280 }
 281
 282 static void logfs_put_read_page(struct page *page)
 283 {
 284         unlock_page(page);
 285         page_cache_release(page);
 286 }
 287
 288 static void logfs_lock_write_page(struct page *page)
 289 {
 290         int loop = 0;
 291
 292         while (unlikely(!trylock_page(page))) {
 293                 if (loop++ > 0x1000) {
 294                         /* Has been observed once so far... */
 295                         printk(KERN_ERR "stack at %p\n", &loop);
 296                         BUG();
 297                 }
 298                 if (PagePreLocked(page)) {
 299                         /* Holder of page lock is waiting for us, it
 300                          * is safe to use this page. */
 301                         break;
 302                 }
 303                 /* Some other process has this page locked and has
 304                  * nothing to do with us.  Wait for it to finish.
 305                  */
 306                 schedule();
 307         }
 308         BUG_ON(!PageLocked(page));
 309 }
 310
 311 static struct page *logfs_get_write_page(struct inode *inode, u64 bix,
 312                 level_t level)
 313 {
 314         struct address_space *mapping = inode->i_mapping;
 315         pgoff_t index = logfs_pack_index(bix, level);
 316         struct page *page;
 317         int err;
 318
 319 repeat:
 320         page = find_get_page(mapping, index);
 321         if (!page) {
 322                 page = __page_cache_alloc(GFP_NOFS);
 323                 if (!page)
 324                         return NULL;
 325                 err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS);
 326                 if (unlikely(err)) {
 327                         page_cache_release(page);
 328                         if (err == -EEXIST)
 329                                 goto repeat;
 330                         return NULL;
 331                 }
 332         } else logfs_lock_write_page(page);
 333         BUG_ON(!PageLocked(page));
 334         return page;
 335 }
 336
 337 static void logfs_unlock_write_page(struct page *page)
 338 {
 339         if (!PagePreLocked(page))
 340                 unlock_page(page);
 341 }
 342
 343 static void logfs_put_write_page(struct page *page)
 344 {
 345         logfs_unlock_write_page(page);
 346         page_cache_release(page);
 347 }
 348
 349 static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level,
 350                 int rw)
 351 {
 352         if (rw == READ)
 353                 return logfs_get_read_page(inode, bix, level);
 354         else
 355                 return logfs_get_write_page(inode, bix, level);
 356 }
 357
 358 static void logfs_put_page(struct page *page, int rw)
 359 {
 360         if (rw == READ)
 361                 logfs_put_read_page(page);
 362         else
 363                 logfs_put_write_page(page);
 364 }
 365
 366 static unsigned long __get_bits(u64 val, int skip, int no)
 367 {
 368         u64 ret = val;
 369
 370         ret >>= skip * no;
 371         ret <<= 64 - no;
 372         ret >>= 64 - no;
 373         return ret;
 374 }
 375
 376 static unsigned long get_bits(u64 val, level_t skip)
 377 {
 378         return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS);
 379 }
 380
 381 static inline void init_shadow_tree(struct super_block *sb,
 382                 struct shadow_tree *tree)
 383 {
 384         struct logfs_super *super = logfs_super(sb);
 385
 386         btree_init_mempool64(&tree->new, super->s_btree_pool);
 387         btree_init_mempool64(&tree->old, super->s_btree_pool);
 388 }
 389
 390 static void indirect_write_block(struct logfs_block *block)
 391 {
 392         struct page *page;
 393         struct inode *inode;
 394         int ret;
 395
 396         page = block->page;
 397         inode = page->mapping->host;
 398         logfs_lock_write_page(page);
 399         ret = logfs_write_buf(inode, page, 0);
 400         logfs_unlock_write_page(page);
 401         /*
 402          * This needs some rework.  Unless you want your filesystem to run
 403          * completely synchronously (you don't), the filesystem will always
 404          * report writes as 'successful' before the actual work has been
 405          * done.  The actual work gets done here and this is where any errors
 406          * will show up.  And there isn't much we can do about it, really.
 407          *
 408          * Some attempts to fix the errors (move from bad blocks, retry io,...)
 409          * have already been done, so anything left should be either a broken
 410          * device or a bug somewhere in logfs itself.  Being relatively new,
 411          * the odds currently favor a bug, so for now the line below isn't
 412          * entirely tasteles.
 413          */
 414         BUG_ON(ret);
 415 }
 416
 417 static void inode_write_block(struct logfs_block *block)
 418 {
 419         struct inode *inode;
 420         int ret;
 421
 422         inode = block->inode;
 423         if (inode->i_ino == LOGFS_INO_MASTER)
 424                 logfs_write_anchor(inode->i_sb);
 425         else {
 426                 ret = __logfs_write_inode(inode, 0);
 427                 /* see indirect_write_block comment */
 428                 BUG_ON(ret);
 429         }
 430 }
 431
 432 static gc_level_t inode_block_level(struct logfs_block *block)
 433 {
 434         BUG_ON(block->inode->i_ino == LOGFS_INO_MASTER);
 435         return GC_LEVEL(LOGFS_MAX_LEVELS);
 436 }
 437
 438 static gc_level_t indirect_block_level(struct logfs_block *block)
 439 {
 440         struct page *page;
 441         struct inode *inode;
 442         u64 bix;
 443         level_t level;
 444
 445         page = block->page;
 446         inode = page->mapping->host;
 447         logfs_unpack_index(page->index, &bix, &level);
 448         return expand_level(inode->i_ino, level);
 449 }
 450
 451 /*
 452  * This silences a false, yet annoying gcc warning.  I hate it when my editor
 453  * jumps into bitops.h each time I recompile this file.
 454  * TODO: Complain to gcc folks about this and upgrade compiler.
 455  */
 456 static unsigned long fnb(const unsigned long *addr,
 457                 unsigned long size, unsigned long offset)
 458 {
 459         return find_next_bit(addr, size, offset);
 460 }
 461
 462 static __be64 inode_val0(struct inode *inode)
 463 {
 464         struct logfs_inode *li = logfs_inode(inode);
 465         u64 val;
 466
 467         /*
 468          * Explicit shifting generates good code, but must match the format
 469          * of the structure.  Add some paranoia just in case.
 470          */
 471         BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0);
 472         BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2);
 473         BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4);
 474
 475         val =   (u64)inode->i_mode << 48 |
 476                 (u64)li->li_height << 40 |
 477                 (u64)li->li_flags;
 478         return cpu_to_be64(val);
 479 }
 480
 481 static int inode_write_alias(struct super_block *sb,
 482                 struct logfs_block *block, write_alias_t *write_one_alias)
 483 {
 484         struct inode *inode = block->inode;
 485         struct logfs_inode *li = logfs_inode(inode);
 486         unsigned long pos;
 487         u64 ino , bix;
 488         __be64 val;
 489         level_t level;
 490         int err;
 491
 492         for (pos = 0; ; pos++) {
 493                 pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
 494                 if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS)
 495                         return 0;
 496
 497                 switch (pos) {
 498                 case INODE_HEIGHT_OFS:
 499                         val = inode_val0(inode);
 500                         break;
 501                 case INODE_USED_OFS:
 502                         val = cpu_to_be64(li->li_used_bytes);;
 503                         break;
 504                 case INODE_SIZE_OFS:
 505                         val = cpu_to_be64(i_size_read(inode));
 506                         break;
 507                 case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1:
 508                         val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]);
 509                         break;
 510                 default:
 511                         BUG();
 512                 }
 513
 514                 ino = LOGFS_INO_MASTER;
 515                 bix = inode->i_ino;
 516                 level = LEVEL(0);
 517                 err = write_one_alias(sb, ino, bix, level, pos, val);
 518                 if (err)
 519                         return err;
 520         }
 521 }
 522
 523 static int indirect_write_alias(struct super_block *sb,
 524                 struct logfs_block *block, write_alias_t *write_one_alias)
 525 {
 526         unsigned long pos;
 527         struct page *page = block->page;
 528         u64 ino , bix;
 529         __be64 *child, val;
 530         level_t level;
 531         int err;
 532
 533         for (pos = 0; ; pos++) {
 534                 pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
 535                 if (pos >= LOGFS_BLOCK_FACTOR)
 536                         return 0;
 537
 538                 ino = page->mapping->host->i_ino;
 539                 logfs_unpack_index(page->index, &bix, &level);
 540                 child = kmap_atomic(page, KM_USER0);
 541                 val = child[pos];
 542                 kunmap_atomic(child, KM_USER0);
 543                 err = write_one_alias(sb, ino, bix, level, pos, val);
 544                 if (err)
 545                         return err;
 546         }
 547 }
 548
 549 int logfs_write_obj_aliases_pagecache(struct super_block *sb)
 550 {
 551         struct logfs_super *super = logfs_super(sb);
 552         struct logfs_block *block;
 553         int err;
 554
 555         list_for_each_entry(block, &super->s_object_alias, alias_list) {
 556                 err = block->ops->write_alias(sb, block, write_alias_journal);
 557                 if (err)
 558                         return err;
 559         }
 560         return 0;
 561 }
 562
 563 void __free_block(struct super_block *sb, struct logfs_block *block)
 564 {
 565         BUG_ON(!list_empty(&block->item_list));
 566         list_del(&block->alias_list);
 567         mempool_free(block, logfs_super(sb)->s_block_pool);
 568 }
 569
 570 static void inode_free_block(struct super_block *sb, struct logfs_block *block)
 571 {
 572         struct inode *inode = block->inode;
 573
 574         logfs_inode(inode)->li_block = NULL;
 575         __free_block(sb, block);
 576 }
 577
 578 static void indirect_free_block(struct super_block *sb,
 579                 struct logfs_block *block)
 580 {
 581         ClearPagePrivate(block->page);
 582         block->page->private = 0;
 583         __free_block(sb, block);
 584 }
 585
 586
 587 static struct logfs_block_ops inode_block_ops = {
 588         .write_block = inode_write_block,
 589         .block_level = inode_block_level,
 590         .free_block = inode_free_block,
 591         .write_alias = inode_write_alias,
 592 };
 593
 594 struct logfs_block_ops indirect_block_ops = {
 595         .write_block = indirect_write_block,
 596         .block_level = indirect_block_level,
 597         .free_block = indirect_free_block,
 598         .write_alias = indirect_write_alias,
 599 };
 600
 601 struct logfs_block *__alloc_block(struct super_block *sb,
 602                 u64 ino, u64 bix, level_t level)
 603 {
 604         struct logfs_super *super = logfs_super(sb);
 605         struct logfs_block *block;
 606
 607         block = mempool_alloc(super->s_block_pool, GFP_NOFS);
 608         memset(block, 0, sizeof(*block));
 609         INIT_LIST_HEAD(&block->alias_list);
 610         INIT_LIST_HEAD(&block->item_list);
 611         block->sb = sb;
 612         block->ino = ino;
 613         block->bix = bix;
 614         block->level = level;
 615         return block;
 616 }
 617
 618 static void alloc_inode_block(struct inode *inode)
 619 {
 620         struct logfs_inode *li = logfs_inode(inode);
 621         struct logfs_block *block;
 622
 623         if (li->li_block)
 624                 return;
 625
 626         block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0);
 627         block->inode = inode;
 628         li->li_block = block;
 629         block->ops = &inode_block_ops;
 630 }
 631
 632 void initialize_block_counters(struct page *page, struct logfs_block *block,
 633                 __be64 *array, int page_is_empty)
 634 {
 635         u64 ptr;
 636         int i, start;
 637
 638         block->partial = 0;
 639         block->full = 0;
 640         start = 0;
 641         if (page->index < first_indirect_block()) {
 642                 /* Counters are pointless on level 0 */
 643                 return;
 644         }
 645         if (page->index == first_indirect_block()) {
 646                 /* Skip unused pointers */
 647                 start = I0_BLOCKS;
 648                 block->full = I0_BLOCKS;
 649         }
 650         if (!page_is_empty) {
 651                 for (i = start; i < LOGFS_BLOCK_FACTOR; i++) {
 652                         ptr = be64_to_cpu(array[i]);
 653                         if (ptr)
 654                                 block->partial++;
 655                         if (ptr & LOGFS_FULLY_POPULATED)
 656                                 block->full++;
 657                 }
 658         }
 659 }
 660
 661 static void alloc_data_block(struct inode *inode, struct page *page)
 662 {
 663         struct logfs_block *block;
 664         u64 bix;
 665         level_t level;
 666
 667         if (PagePrivate(page))
 668                 return;
 669
 670         logfs_unpack_index(page->index, &bix, &level);
 671         block = __alloc_block(inode->i_sb, inode->i_ino, bix, level);
 672         block->page = page;
 673         SetPagePrivate(page);
 674         page->private = (unsigned long)block;
 675         block->ops = &indirect_block_ops;
 676 }
 677
 678 static void alloc_indirect_block(struct inode *inode, struct page *page,
 679                 int page_is_empty)
 680 {
 681         struct logfs_block *block;
 682         __be64 *array;
 683
 684         if (PagePrivate(page))
 685                 return;
 686
 687         alloc_data_block(inode, page);
 688
 689         block = logfs_block(page);
 690         array = kmap_atomic(page, KM_USER0);
 691         initialize_block_counters(page, block, array, page_is_empty);
 692         kunmap_atomic(array, KM_USER0);
 693 }
 694
 695 static void block_set_pointer(struct page *page, int index, u64 ptr)
 696 {
 697         struct logfs_block *block = logfs_block(page);
 698         __be64 *array;
 699         u64 oldptr;
 700
 701         BUG_ON(!block);
 702         array = kmap_atomic(page, KM_USER0);
 703         oldptr = be64_to_cpu(array[index]);
 704         array[index] = cpu_to_be64(ptr);
 705         kunmap_atomic(array, KM_USER0);
 706         SetPageUptodate(page);
 707
 708         block->full += !!(ptr & LOGFS_FULLY_POPULATED)
 709                 - !!(oldptr & LOGFS_FULLY_POPULATED);
 710         block->partial += !!ptr - !!oldptr;
 711 }
 712
 713 static u64 block_get_pointer(struct page *page, int index)
 714 {
 715         __be64 *block;
 716         u64 ptr;
 717
 718         block = kmap_atomic(page, KM_USER0);
 719         ptr = be64_to_cpu(block[index]);
 720         kunmap_atomic(block, KM_USER0);
 721         return ptr;
 722 }
 723
 724 static int logfs_read_empty(struct page *page)
 725 {
 726         zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 727         return 0;
 728 }
 729
 730 static int logfs_read_direct(struct inode *inode, struct page *page)
 731 {
 732         struct logfs_inode *li = logfs_inode(inode);
 733         pgoff_t index = page->index;
 734         u64 block;
 735
 736         block = li->li_data[index];
 737         if (!block)
 738                 return logfs_read_empty(page);
 739
 740         return logfs_segment_read(inode, page, block, index, 0);
 741 }
 742
 743 static int logfs_read_loop(struct inode *inode, struct page *page,
 744                 int rw_context)
 745 {
 746         struct logfs_inode *li = logfs_inode(inode);
 747         u64 bix, bofs = li->li_data[INDIRECT_INDEX];
 748         level_t level, target_level;
 749         int ret;
 750         struct page *ipage;
 751
 752         logfs_unpack_index(page->index, &bix, &target_level);
 753         if (!bofs)
 754                 return logfs_read_empty(page);
 755
 756         if (bix >= maxbix(li->li_height))
 757                 return logfs_read_empty(page);
 758
 759         for (level = LEVEL(li->li_height);
 760                         (__force u8)level > (__force u8)target_level;
 761                         level = SUBLEVEL(level)){
 762                 ipage = logfs_get_page(inode, bix, level, rw_context);
 763                 if (!ipage)
 764                         return -ENOMEM;
 765
 766                 ret = logfs_segment_read(inode, ipage, bofs, bix, level);
 767                 if (ret) {
 768                         logfs_put_read_page(ipage);
 769                         return ret;
 770                 }
 771
 772                 bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
 773                 logfs_put_page(ipage, rw_context);
 774                 if (!bofs)
 775                         return logfs_read_empty(page);
 776         }
 777
 778         return logfs_segment_read(inode, page, bofs, bix, 0);
 779 }
 780
 781 static int logfs_read_block(struct inode *inode, struct page *page,
 782                 int rw_context)
 783 {
 784         pgoff_t index = page->index;
 785
 786         if (index < I0_BLOCKS)
 787                 return logfs_read_direct(inode, page);
 788         return logfs_read_loop(inode, page, rw_context);
 789 }
 790
 791 static int logfs_exist_loop(struct inode *inode, u64 bix)
 792 {
 793         struct logfs_inode *li = logfs_inode(inode);
 794         u64 bofs = li->li_data[INDIRECT_INDEX];
 795         level_t level;
 796         int ret;
 797         struct page *ipage;
 798
 799         if (!bofs)
 800                 return 0;
 801         if (bix >= maxbix(li->li_height))
 802                 return 0;
 803
 804         for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
 805                 ipage = logfs_get_read_page(inode, bix, level);
 806                 if (!ipage)
 807                         return -ENOMEM;
 808
 809                 ret = logfs_segment_read(inode, ipage, bofs, bix, level);
 810                 if (ret) {
 811                         logfs_put_read_page(ipage);
 812                         return ret;
 813                 }
 814
 815                 bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
 816                 logfs_put_read_page(ipage);
 817                 if (!bofs)
 818                         return 0;
 819         }
 820
 821         return 1;
 822 }
 823
 824 int logfs_exist_block(struct inode *inode, u64 bix)
 825 {
 826         struct logfs_inode *li = logfs_inode(inode);
 827
 828         if (bix < I0_BLOCKS)
 829                 return !!li->li_data[bix];
 830         return logfs_exist_loop(inode, bix);
 831 }
 832
 833 static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data)
 834 {
 835         struct logfs_inode *li = logfs_inode(inode);
 836
 837         for (; bix < I0_BLOCKS; bix++)
 838                 if (data ^ (li->li_data[bix] == 0))
 839                         return bix;
 840         return I0_BLOCKS;
 841 }
 842
 843 static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data)
 844 {
 845         struct logfs_inode *li = logfs_inode(inode);
 846         __be64 *rblock;
 847         u64 increment, bofs = li->li_data[INDIRECT_INDEX];
 848         level_t level;
 849         int ret, slot;
 850         struct page *page;
 851
 852         BUG_ON(!bofs);
 853
 854         for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
 855                 increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1));
 856                 page = logfs_get_read_page(inode, bix, level);
 857                 if (!page)
 858                         return bix;
 859
 860                 ret = logfs_segment_read(inode, page, bofs, bix, level);
 861                 if (ret) {
 862                         logfs_put_read_page(page);
 863                         return bix;
 864                 }
 865
 866                 slot = get_bits(bix, SUBLEVEL(level));
 867                 rblock = kmap_atomic(page, KM_USER0);
 868                 while (slot < LOGFS_BLOCK_FACTOR) {
 869                         if (data && (rblock[slot] != 0))
 870                                 break;
 871                         if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED))
 872                                 break;
 873                         slot++;
 874                         bix += increment;
 875                         bix &= ~(increment - 1);
 876                 }
 877                 if (slot >= LOGFS_BLOCK_FACTOR) {
 878                         kunmap_atomic(rblock, KM_USER0);
 879                         logfs_put_read_page(page);
 880                         return bix;
 881                 }
 882                 bofs = be64_to_cpu(rblock[slot]);
 883                 kunmap_atomic(rblock, KM_USER0);
 884                 logfs_put_read_page(page);
 885                 if (!bofs) {
 886                         BUG_ON(data);
 887                         return bix;
 888                 }
 889         }
 890         return bix;
 891 }
 892
 893 /**
 894  * logfs_seek_hole - find next hole starting at a given block index
 895  * @inode:              inode to search in
 896  * @bix:                block index to start searching
 897  *
 898  * Returns next hole.  If the file doesn't contain any further holes, the
 899  * block address next to eof is returned instead.
 900  */
 901 u64 logfs_seek_hole(struct inode *inode, u64 bix)
 902 {
 903         struct logfs_inode *li = logfs_inode(inode);
 904
 905         if (bix < I0_BLOCKS) {
 906                 bix = seek_holedata_direct(inode, bix, 0);
 907                 if (bix < I0_BLOCKS)
 908                         return bix;
 909         }
 910
 911         if (!li->li_data[INDIRECT_INDEX])
 912                 return bix;
 913         else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED)
 914                 bix = maxbix(li->li_height);
 915         else {
 916                 bix = seek_holedata_loop(inode, bix, 0);
 917                 if (bix < maxbix(li->li_height))
 918                         return bix;
 919                 /* Should not happen anymore.  But if some port writes semi-
 920                  * corrupt images (as this one used to) we might run into it.
 921                  */
 922                 WARN_ON_ONCE(bix == maxbix(li->li_height));
 923         }
 924
 925         return bix;
 926 }
 927
 928 static u64 __logfs_seek_data(struct inode *inode, u64 bix)
 929 {
 930         struct logfs_inode *li = logfs_inode(inode);
 931
 932         if (bix < I0_BLOCKS) {
 933                 bix = seek_holedata_direct(inode, bix, 1);
 934                 if (bix < I0_BLOCKS)
 935                         return bix;
 936         }
 937
 938         if (bix < maxbix(li->li_height)) {
 939                 if (!li->li_data[INDIRECT_INDEX])
 940                         bix = maxbix(li->li_height);
 941                 else
 942                         return seek_holedata_loop(inode, bix, 1);
 943         }
 944
 945         return bix;
 946 }
 947
 948 /**
 949  * logfs_seek_data - find next data block after a given block index
 950  * @inode:              inode to search in
 951  * @bix:                block index to start searching
 952  *
 953  * Returns next data block.  If the file doesn't contain any further data
 954  * blocks, the last block in the file is returned instead.
 955  */
 956 u64 logfs_seek_data(struct inode *inode, u64 bix)
 957 {
 958         struct super_block *sb = inode->i_sb;
 959         u64 ret, end;
 960
 961         ret = __logfs_seek_data(inode, bix);
 962         end = i_size_read(inode) >> sb->s_blocksize_bits;
 963         if (ret >= end)
 964                 ret = max(bix, end);
 965         return ret;
 966 }
 967
 968 static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs)
 969 {
 970         return pure_ofs(li->li_data[bix]) == ofs;
 971 }
 972
 973 static int __logfs_is_valid_loop(struct inode *inode, u64 bix,
 974                 u64 ofs, u64 bofs)
 975 {
 976         struct logfs_inode *li = logfs_inode(inode);
 977         level_t level;
 978         int ret;
 979         struct page *page;
 980
 981         for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){
 982                 page = logfs_get_write_page(inode, bix, level);
 983                 BUG_ON(!page);
 984
 985                 ret = logfs_segment_read(inode, page, bofs, bix, level);
 986                 if (ret) {
 987                         logfs_put_write_page(page);
 988                         return 0;
 989                 }
 990
 991                 bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level)));
 992                 logfs_put_write_page(page);
 993                 if (!bofs)
 994                         return 0;
 995
 996                 if (pure_ofs(bofs) == ofs)
 997                         return 1;
 998         }
 999         return 0;
1000 }
1001
1002 static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs)
1003 {
1004         struct logfs_inode *li = logfs_inode(inode);
1005         u64 bofs = li->li_data[INDIRECT_INDEX];
1006
1007         if (!bofs)
1008                 return 0;
1009
1010         if (bix >= maxbix(li->li_height))
1011                 return 0;
1012
1013         if (pure_ofs(bofs) == ofs)
1014                 return 1;
1015
1016         return __logfs_is_valid_loop(inode, bix, ofs, bofs);
1017 }
1018
1019 static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
1020 {
1021         struct logfs_inode *li = logfs_inode(inode);
1022
1023         if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
1024                 return 0;
1025
1026         if (bix < I0_BLOCKS)
1027                 return logfs_is_valid_direct(li, bix, ofs);
1028         return logfs_is_valid_loop(inode, bix, ofs);
1029 }
1030
1031 /**
1032  * logfs_is_valid_block - check whether this block is still valid
1033  *
1034  * @sb  - superblock
1035  * @ofs - block physical offset
1036  * @ino - block inode number
1037  * @bix - block index
1038  * @level - block level
1039  *
1040  * Returns 0 if the block is invalid, 1 if it is valid and 2 if it will
1041  * become invalid once the journal is written.
1042  */
1043 int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
1044                 gc_level_t gc_level)
1045 {
1046         struct logfs_super *super = logfs_super(sb);
1047         struct inode *inode;
1048         int ret, cookie;
1049
1050         /* Umount closes a segment with free blocks remaining.  Those
1051          * blocks are by definition invalid. */
1052         if (ino == -1)
1053                 return 0;
1054
1055         LOGFS_BUG_ON((u64)(u_long)ino != ino, sb);
1056
1057         inode = logfs_safe_iget(sb, ino, &cookie);
1058         if (IS_ERR(inode))
1059                 goto invalid;
1060
1061         ret = __logfs_is_valid_block(inode, bix, ofs);
1062         logfs_safe_iput(inode, cookie);
1063         if (ret)
1064                 return ret;
1065
1066 invalid:
1067         /* Block is nominally invalid, but may still sit in the shadow tree,
1068          * waiting for a journal commit.
1069          */
1070         if (btree_lookup64(&super->s_shadow_tree.old, ofs))
1071                 return 2;
1072         return 0;
1073 }
1074
1075 int logfs_readpage_nolock(struct page *page)
1076 {
1077         struct inode *inode = page->mapping->host;
1078         int ret = -EIO;
1079
1080         ret = logfs_read_block(inode, page, READ);
1081
1082         if (ret) {
1083                 ClearPageUptodate(page);
1084                 SetPageError(page);
1085         } else {
1086                 SetPageUptodate(page);
1087                 ClearPageError(page);
1088         }
1089         flush_dcache_page(page);
1090
1091         return ret;
1092 }
1093
1094 static int logfs_reserve_bytes(struct inode *inode, int bytes)
1095 {
1096         struct logfs_super *super = logfs_super(inode->i_sb);
1097         u64 available = super->s_free_bytes + super->s_dirty_free_bytes
1098                         - super->s_dirty_used_bytes - super->s_dirty_pages;
1099
1100         if (!bytes)
1101                 return 0;
1102
1103         if (available < bytes)
1104                 return -ENOSPC;
1105
1106         if (available < bytes + super->s_root_reserve &&
1107                         !capable(CAP_SYS_RESOURCE))
1108                 return -ENOSPC;
1109
1110         return 0;
1111 }
1112
1113 int get_page_reserve(struct inode *inode, struct page *page)
1114 {
1115         struct logfs_super *super = logfs_super(inode->i_sb);
1116         int ret;
1117
1118         if (logfs_block(page) && logfs_block(page)->reserved_bytes)
1119                 return 0;
1120
1121         logfs_get_wblocks(inode->i_sb, page, WF_LOCK);
1122         ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE);
1123         if (!ret) {
1124                 alloc_data_block(inode, page);
1125                 logfs_block(page)->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE;
1126                 super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE;
1127         }
1128         logfs_put_wblocks(inode->i_sb, page, WF_LOCK);
1129         return ret;
1130 }
1131
1132 /*
1133  * We are protected by write lock.  Push victims up to superblock level
1134  * and release transaction when appropriate.
1135  */
1136 /* FIXME: This is currently called from the wrong spots. */
1137 static void logfs_handle_transaction(struct inode *inode,
1138                 struct logfs_transaction *ta)
1139 {
1140         struct logfs_super *super = logfs_super(inode->i_sb);
1141
1142         if (!ta)
1143                 return;
1144         logfs_inode(inode)->li_block->ta = NULL;
1145
1146         if (inode->i_ino != LOGFS_INO_MASTER) {
1147                 BUG(); /* FIXME: Yes, this needs more thought */
1148                 /* just remember the transaction until inode is written */
1149                 //BUG_ON(logfs_inode(inode)->li_transaction);
1150                 //logfs_inode(inode)->li_transaction = ta;
1151                 return;
1152         }
1153
1154         switch (ta->state) {
1155         case CREATE_1: /* fall through */
1156         case UNLINK_1:
1157                 BUG_ON(super->s_victim_ino);
1158                 super->s_victim_ino = ta->ino;
1159                 break;
1160         case CREATE_2: /* fall through */
1161         case UNLINK_2:
1162                 BUG_ON(super->s_victim_ino != ta->ino);
1163                 super->s_victim_ino = 0;
1164                 /* transaction ends here - free it */
1165                 kfree(ta);
1166                 break;
1167         case CROSS_RENAME_1:
1168                 BUG_ON(super->s_rename_dir);
1169                 BUG_ON(super->s_rename_pos);
1170                 super->s_rename_dir = ta->dir;
1171                 super->s_rename_pos = ta->pos;
1172                 break;
1173         case CROSS_RENAME_2:
1174                 BUG_ON(super->s_rename_dir != ta->dir);
1175                 BUG_ON(super->s_rename_pos != ta->pos);
1176                 super->s_rename_dir = 0;
1177                 super->s_rename_pos = 0;
1178                 kfree(ta);
1179                 break;
1180         case TARGET_RENAME_1:
1181                 BUG_ON(super->s_rename_dir);
1182                 BUG_ON(super->s_rename_pos);
1183                 BUG_ON(super->s_victim_ino);
1184                 super->s_rename_dir = ta->dir;
1185                 super->s_rename_pos = ta->pos;
1186                 super->s_victim_ino = ta->ino;
1187                 break;
1188         case TARGET_RENAME_2:
1189                 BUG_ON(super->s_rename_dir != ta->dir);
1190                 BUG_ON(super->s_rename_pos != ta->pos);
1191                 BUG_ON(super->s_victim_ino != ta->ino);
1192                 super->s_rename_dir = 0;
1193                 super->s_rename_pos = 0;
1194                 break;
1195         case TARGET_RENAME_3:
1196                 BUG_ON(super->s_rename_dir);
1197                 BUG_ON(super->s_rename_pos);
1198                 BUG_ON(super->s_victim_ino != ta->ino);
1199                 super->s_victim_ino = 0;
1200                 kfree(ta);
1201                 break;
1202         default:
1203                 BUG();
1204         }
1205 }
1206
1207 /*
1208  * Not strictly a reservation, but rather a check that we still have enough
1209  * space to satisfy the write.
1210  */
1211 static int logfs_reserve_blocks(struct inode *inode, int blocks)
1212 {
1213         return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE);
1214 }
1215
1216 struct write_control {
1217         u64 ofs;
1218         long flags;
1219 };
1220
1221 static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix,
1222                 level_t level, u64 old_ofs)
1223 {
1224         struct logfs_super *super = logfs_super(inode->i_sb);
1225         struct logfs_shadow *shadow;
1226
1227         shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS);
1228         memset(shadow, 0, sizeof(*shadow));
1229         shadow->ino = inode->i_ino;
1230         shadow->bix = bix;
1231         shadow->gc_level = expand_level(inode->i_ino, level);
1232         shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED;
1233         return shadow;
1234 }
1235
1236 static void free_shadow(struct inode *inode, struct logfs_shadow *shadow)
1237 {
1238         struct logfs_super *super = logfs_super(inode->i_sb);
1239
1240         mempool_free(shadow, super->s_shadow_pool);
1241 }
1242
1243 /**
1244  * fill_shadow_tree - Propagate shadow tree changes due to a write
1245  * @inode:      Inode owning the page
1246  * @page:       Struct page that was written
1247  * @shadow:     Shadow for the current write
1248  *
1249  * Writes in logfs can result in two semi-valid objects.  The old object
1250  * is still valid as long as it can be reached by following pointers on
1251  * the medium.  Only when writes propagate all the way up to the journal
1252  * has the new object safely replaced the old one.
1253  *
1254  * To handle this problem, a struct logfs_shadow is used to represent
1255  * every single write.  It is attached to the indirect block, which is
1256  * marked dirty.  When the indirect block is written, its shadows are
1257  * handed up to the next indirect block (or inode).  Untimately they
1258  * will reach the master inode and be freed upon journal commit.
1259  *
1260  * This function handles a single step in the propagation.  It adds the
1261  * shadow for the current write to the tree, along with any shadows in
1262  * the page's tree, in case it was an indirect block.  If a page is
1263  * written, the inode parameter is left NULL, if an inode is written,
1264  * the page parameter is left NULL.
1265  */
1266 static void fill_shadow_tree(struct inode *inode, struct page *page,
1267                 struct logfs_shadow *shadow)
1268 {
1269         struct logfs_super *super = logfs_super(inode->i_sb);
1270         struct logfs_block *block = logfs_block(page);
1271         struct shadow_tree *tree = &super->s_shadow_tree;
1272
1273         if (PagePrivate(page)) {
1274                 if (block->alias_map)
1275                         super->s_no_object_aliases -= bitmap_weight(
1276                                         block->alias_map, LOGFS_BLOCK_FACTOR);
1277                 logfs_handle_transaction(inode, block->ta);
1278                 block->ops->free_block(inode->i_sb, block);
1279         }
1280         if (shadow) {
1281                 if (shadow->old_ofs)
1282                         btree_insert64(&tree->old, shadow->old_ofs, shadow,
1283                                         GFP_NOFS);
1284                 else
1285                         btree_insert64(&tree->new, shadow->new_ofs, shadow,
1286                                         GFP_NOFS);
1287
1288                 super->s_dirty_used_bytes += shadow->new_len;
1289                 super->s_dirty_free_bytes += shadow->old_len;
1290         }
1291 }
1292
1293 static void logfs_set_alias(struct super_block *sb, struct logfs_block *block,
1294                 long child_no)
1295 {
1296         struct logfs_super *super = logfs_super(sb);
1297
1298         if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) {
1299                 /* Aliases in the master inode are pointless. */
1300                 return;
1301         }
1302
1303         if (!test_bit(child_no, block->alias_map)) {
1304                 set_bit(child_no, block->alias_map);
1305                 super->s_no_object_aliases++;
1306         }
1307         list_move_tail(&block->alias_list, &super->s_object_alias);
1308 }
1309
1310 /*
1311  * Object aliases can and often do change the size and occupied space of a
1312  * file.  So not only do we have to change the pointers, we also have to
1313  * change inode->i_size and li->li_used_bytes.  Which is done by setting
1314  * another two object aliases for the inode itself.
1315  */
1316 static void set_iused(struct inode *inode, struct logfs_shadow *shadow)
1317 {
1318         struct logfs_inode *li = logfs_inode(inode);
1319
1320         if (shadow->new_len == shadow->old_len)
1321                 return;
1322
1323         alloc_inode_block(inode);
1324         li->li_used_bytes += shadow->new_len - shadow->old_len;
1325         __logfs_set_blocks(inode);
1326         logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS);
1327         logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS);
1328 }
1329
1330 static int logfs_write_i0(struct inode *inode, struct page *page,
1331                 struct write_control *wc)
1332 {
1333         struct logfs_shadow *shadow;
1334         u64 bix;
1335         level_t level;
1336         int full, err = 0;
1337
1338         logfs_unpack_index(page->index, &bix, &level);
1339         if (wc->ofs == 0)
1340                 if (logfs_reserve_blocks(inode, 1))
1341                         return -ENOSPC;
1342
1343         shadow = alloc_shadow(inode, bix, level, wc->ofs);
1344         if (wc->flags & WF_WRITE)
1345                 err = logfs_segment_write(inode, page, shadow);
1346         if (wc->flags & WF_DELETE)
1347                 logfs_segment_delete(inode, shadow);
1348         if (err) {
1349                 free_shadow(inode, shadow);
1350                 return err;
1351         }
1352
1353         set_iused(inode, shadow);
1354         full = 1;
1355         if (level != 0) {
1356                 alloc_indirect_block(inode, page, 0);
1357                 full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR;
1358         }
1359         fill_shadow_tree(inode, page, shadow);
1360         wc->ofs = shadow->new_ofs;
1361         if (wc->ofs && full)
1362                 wc->ofs |= LOGFS_FULLY_POPULATED;
1363         return 0;
1364 }
1365
1366 static int logfs_write_direct(struct inode *inode, struct page *page,
1367                 long flags)
1368 {
1369         struct logfs_inode *li = logfs_inode(inode);
1370         struct write_control wc = {
1371                 .ofs = li->li_data[page->index],
1372                 .flags = flags,
1373         };
1374         int err;
1375
1376         alloc_inode_block(inode);
1377
1378         err = logfs_write_i0(inode, page, &wc);
1379         if (err)
1380                 return err;
1381
1382         li->li_data[page->index] = wc.ofs;
1383         logfs_set_alias(inode->i_sb, li->li_block,
1384                         page->index + INODE_POINTER_OFS);
1385         return 0;
1386 }
1387
1388 static int ptr_change(u64 ofs, struct page *page)
1389 {
1390         struct logfs_block *block = logfs_block(page);
1391         int empty0, empty1, full0, full1;
1392
1393         empty0 = ofs == 0;
1394         empty1 = block->partial == 0;
1395         if (empty0 != empty1)
1396                 return 1;
1397
1398         /* The !! is necessary to shrink result to int */
1399         full0 = !!(ofs & LOGFS_FULLY_POPULATED);
1400         full1 = block->full == LOGFS_BLOCK_FACTOR;
1401         if (full0 != full1)
1402                 return 1;
1403         return 0;
1404 }
1405
1406 static int __logfs_write_rec(struct inode *inode, struct page *page,
1407                 struct write_control *this_wc,
1408                 pgoff_t bix, level_t target_level, level_t level)
1409 {
1410         int ret, page_empty = 0;
1411         int child_no = get_bits(bix, SUBLEVEL(level));
1412         struct page *ipage;
1413         struct write_control child_wc = {
1414                 .flags = this_wc->flags,
1415         };
1416
1417         ipage = logfs_get_write_page(inode, bix, level);
1418         if (!ipage)
1419                 return -ENOMEM;
1420
1421         if (this_wc->ofs) {
1422                 ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
1423                 if (ret)
1424                         goto out;
1425         } else if (!PageUptodate(ipage)) {
1426                 page_empty = 1;
1427                 logfs_read_empty(ipage);
1428         }
1429
1430         child_wc.ofs = block_get_pointer(ipage, child_no);
1431
1432         if ((__force u8)level-1 > (__force u8)target_level)
1433                 ret = __logfs_write_rec(inode, page, &child_wc, bix,
1434                                 target_level, SUBLEVEL(level));
1435         else
1436                 ret = logfs_write_i0(inode, page, &child_wc);
1437
1438         if (ret)
1439                 goto out;
1440
1441         alloc_indirect_block(inode, ipage, page_empty);
1442         block_set_pointer(ipage, child_no, child_wc.ofs);
1443         /* FIXME: first condition seems superfluous */
1444         if (child_wc.ofs || logfs_block(ipage)->partial)
1445                 this_wc->flags |= WF_WRITE;
1446         /* the condition on this_wc->ofs ensures that we won't consume extra
1447          * space for indirect blocks in the future, which we cannot reserve */
1448         if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage))
1449                 ret = logfs_write_i0(inode, ipage, this_wc);
1450         else
1451                 logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no);
1452 out:
1453         logfs_put_write_page(ipage);
1454         return ret;
1455 }
1456
1457 static int logfs_write_rec(struct inode *inode, struct page *page,
1458                 pgoff_t bix, level_t target_level, long flags)
1459 {
1460         struct logfs_inode *li = logfs_inode(inode);
1461         struct write_control wc = {
1462                 .ofs = li->li_data[INDIRECT_INDEX],
1463                 .flags = flags,
1464         };
1465         int ret;
1466
1467         alloc_inode_block(inode);
1468
1469         if (li->li_height > (__force u8)target_level)
1470                 ret = __logfs_write_rec(inode, page, &wc, bix, target_level,
1471                                 LEVEL(li->li_height));
1472         else
1473                 ret = logfs_write_i0(inode, page, &wc);
1474         if (ret)
1475                 return ret;
1476
1477         if (li->li_data[INDIRECT_INDEX] != wc.ofs) {
1478                 li->li_data[INDIRECT_INDEX] = wc.ofs;
1479                 logfs_set_alias(inode->i_sb, li->li_block,
1480                                 INDIRECT_INDEX + INODE_POINTER_OFS);
1481         }
1482         return ret;
1483 }
1484
1485 void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta)
1486 {
1487         alloc_inode_block(inode);
1488         logfs_inode(inode)->li_block->ta = ta;
1489 }
1490
1491 void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta)
1492 {
1493         struct logfs_block *block = logfs_inode(inode)->li_block;
1494
1495         if (block && block->ta)
1496                 block->ta = NULL;
1497 }
1498
1499 static int grow_inode(struct inode *inode, u64 bix, level_t level)
1500 {
1501         struct logfs_inode *li = logfs_inode(inode);
1502         u8 height = (__force u8)level;
1503         struct page *page;
1504         struct write_control wc = {
1505                 .flags = WF_WRITE,
1506         };
1507         int err;
1508
1509         BUG_ON(height > 5 || li->li_height > 5);
1510         while (height > li->li_height || bix >= maxbix(li->li_height)) {
1511                 page = logfs_get_write_page(inode, I0_BLOCKS + 1,
1512                                 LEVEL(li->li_height + 1));
1513                 if (!page)
1514                         return -ENOMEM;
1515                 logfs_read_empty(page);
1516                 alloc_indirect_block(inode, page, 1);
1517                 block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]);
1518                 err = logfs_write_i0(inode, page, &wc);
1519                 logfs_put_write_page(page);
1520                 if (err)
1521                         return err;
1522                 li->li_data[INDIRECT_INDEX] = wc.ofs;
1523                 wc.ofs = 0;
1524                 li->li_height++;
1525                 logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS);
1526         }
1527         return 0;
1528 }
1529
1530 static int __logfs_write_buf(struct inode *inode, struct page *page, long flags)
1531 {
1532         struct logfs_super *super = logfs_super(inode->i_sb);
1533         pgoff_t index = page->index;
1534         u64 bix;
1535         level_t level;
1536         int err;
1537
1538         flags |= WF_WRITE | WF_DELETE;
1539         inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1540
1541         logfs_unpack_index(index, &bix, &level);
1542         if (logfs_block(page) && logfs_block(page)->reserved_bytes)
1543                 super->s_dirty_pages -= logfs_block(page)->reserved_bytes;
1544
1545         if (index < I0_BLOCKS)
1546                 return logfs_write_direct(inode, page, flags);
1547
1548         bix = adjust_bix(bix, level);
1549         err = grow_inode(inode, bix, level);
1550         if (err)
1551                 return err;
1552         return logfs_write_rec(inode, page, bix, level, flags);
1553 }
1554
1555 int logfs_write_buf(struct inode *inode, struct page *page, long flags)
1556 {
1557         struct super_block *sb = inode->i_sb;
1558         int ret;
1559
1560         logfs_get_wblocks(sb, page, flags & WF_LOCK);
1561         ret = __logfs_write_buf(inode, page, flags);
1562         logfs_put_wblocks(sb, page, flags & WF_LOCK);
1563         return ret;
1564 }
1565
1566 static int __logfs_delete(struct inode *inode, struct page *page)
1567 {
1568         long flags = WF_DELETE;
1569
1570         inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1571
1572         if (page->index < I0_BLOCKS)
1573                 return logfs_write_direct(inode, page, flags);
1574         return logfs_write_rec(inode, page, page->index, 0, flags);
1575 }
1576
1577 int logfs_delete(struct inode *inode, pgoff_t index,
1578                 struct shadow_tree *shadow_tree)
1579 {
1580         struct super_block *sb = inode->i_sb;
1581         struct page *page;
1582         int ret;
1583
1584         page = logfs_get_read_page(inode, index, 0);
1585         if (!page)
1586                 return -ENOMEM;
1587
1588         logfs_get_wblocks(sb, page, 1);
1589         ret = __logfs_delete(inode, page);
1590         logfs_put_wblocks(sb, page, 1);
1591
1592         logfs_put_read_page(page);
1593
1594         return ret;
1595 }
1596
1597 /* Rewrite cannot mark the inode dirty but has to write it immediatly. */
1598 int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
1599                 gc_level_t gc_level, long flags)
1600 {
1601         level_t level = shrink_level(gc_level);
1602         struct page *page;
1603         int err;
1604
1605         page = logfs_get_write_page(inode, bix, level);
1606         if (!page)
1607                 return -ENOMEM;
1608
1609         err = logfs_segment_read(inode, page, ofs, bix, level);
1610         if (!err) {
1611                 if (level != 0)
1612                         alloc_indirect_block(inode, page, 0);
1613                 err = logfs_write_buf(inode, page, flags);
1614         }
1615         logfs_put_write_page(page);
1616         return err;
1617 }
1618
1619 static int truncate_data_block(struct inode *inode, struct page *page,
1620                 u64 ofs, struct logfs_shadow *shadow, u64 size)
1621 {
1622         loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits;
1623         u64 bix;
1624         level_t level;
1625         int err;
1626
1627         /* Does truncation happen within this page? */
1628         if (size <= pageofs || size - pageofs >= PAGE_SIZE)
1629                 return 0;
1630
1631         logfs_unpack_index(page->index, &bix, &level);
1632         BUG_ON(level != 0);
1633
1634         err = logfs_segment_read(inode, page, ofs, bix, level);
1635         if (err)
1636                 return err;
1637
1638         zero_user_segment(page, size - pageofs, PAGE_CACHE_SIZE);
1639         return logfs_segment_write(inode, page, shadow);
1640 }
1641
1642 static int logfs_truncate_i0(struct inode *inode, struct page *page,
1643                 struct write_control *wc, u64 size)
1644 {
1645         struct logfs_shadow *shadow;
1646         u64 bix;
1647         level_t level;
1648         int err = 0;
1649
1650         logfs_unpack_index(page->index, &bix, &level);
1651         BUG_ON(level != 0);
1652         shadow = alloc_shadow(inode, bix, level, wc->ofs);
1653
1654         err = truncate_data_block(inode, page, wc->ofs, shadow, size);
1655         if (err) {
1656                 free_shadow(inode, shadow);
1657                 return err;
1658         }
1659
1660         logfs_segment_delete(inode, shadow);
1661         set_iused(inode, shadow);
1662         fill_shadow_tree(inode, page, shadow);
1663         wc->ofs = shadow->new_ofs;
1664         return 0;
1665 }
1666
1667 static int logfs_truncate_direct(struct inode *inode, u64 size)
1668 {
1669         struct logfs_inode *li = logfs_inode(inode);
1670         struct write_control wc;
1671         struct page *page;
1672         int e;
1673         int err;
1674
1675         alloc_inode_block(inode);
1676
1677         for (e = I0_BLOCKS - 1; e >= 0; e--) {
1678                 if (size > (e+1) * LOGFS_BLOCKSIZE)
1679                         break;
1680
1681                 wc.ofs = li->li_data[e];
1682                 if (!wc.ofs)
1683                         continue;
1684
1685                 page = logfs_get_write_page(inode, e, 0);
1686                 if (!page)
1687                         return -ENOMEM;
1688                 err = logfs_segment_read(inode, page, wc.ofs, e, 0);
1689                 if (err) {
1690                         logfs_put_write_page(page);
1691                         return err;
1692                 }
1693                 err = logfs_truncate_i0(inode, page, &wc, size);
1694                 logfs_put_write_page(page);
1695                 if (err)
1696                         return err;
1697
1698                 li->li_data[e] = wc.ofs;
1699         }
1700         return 0;
1701 }
1702
1703 /* FIXME: these need to become per-sb once we support different blocksizes */
1704 static u64 __logfs_step[] = {
1705         1,
1706         I1_BLOCKS,
1707         I2_BLOCKS,
1708         I3_BLOCKS,
1709 };
1710
1711 static u64 __logfs_start_index[] = {
1712         I0_BLOCKS,
1713         I1_BLOCKS,
1714         I2_BLOCKS,
1715         I3_BLOCKS
1716 };
1717
1718 static inline u64 logfs_step(level_t level)
1719 {
1720         return __logfs_step[(__force u8)level];
1721 }
1722
1723 static inline u64 logfs_factor(u8 level)
1724 {
1725         return __logfs_step[level] * LOGFS_BLOCKSIZE;
1726 }
1727
1728 static inline u64 logfs_start_index(level_t level)
1729 {
1730         return __logfs_start_index[(__force u8)level];
1731 }
1732
1733 static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level)
1734 {
1735         logfs_unpack_index(index, bix, level);
1736         if (*bix <= logfs_start_index(SUBLEVEL(*level)))
1737                 *bix = 0;
1738 }
1739
1740 static int __logfs_truncate_rec(struct inode *inode, struct page *ipage,
1741                 struct write_control *this_wc, u64 size)
1742 {
1743         int truncate_happened = 0;
1744         int e, err = 0;
1745         u64 bix, child_bix, next_bix;
1746         level_t level;
1747         struct page *page;
1748         struct write_control child_wc = { /* FIXME: flags */ };
1749
1750         logfs_unpack_raw_index(ipage->index, &bix, &level);
1751         err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
1752         if (err)
1753                 return err;
1754
1755         for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) {
1756                 child_bix = bix + e * logfs_step(SUBLEVEL(level));
1757                 next_bix = child_bix + logfs_step(SUBLEVEL(level));
1758                 if (size > next_bix * LOGFS_BLOCKSIZE)
1759                         break;
1760
1761                 child_wc.ofs = pure_ofs(block_get_pointer(ipage, e));
1762                 if (!child_wc.ofs)
1763                         continue;
1764
1765                 page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level));
1766                 if (!page)
1767                         return -ENOMEM;
1768
1769                 if ((__force u8)level > 1)
1770                         err = __logfs_truncate_rec(inode, page, &child_wc, size);
1771                 else
1772                         err = logfs_truncate_i0(inode, page, &child_wc, size);
1773                 logfs_put_write_page(page);
1774                 if (err)
1775                         return err;
1776
1777                 truncate_happened = 1;
1778                 alloc_indirect_block(inode, ipage, 0);
1779                 block_set_pointer(ipage, e, child_wc.ofs);
1780         }
1781
1782         if (!truncate_happened) {
1783                 printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size);
1784                 return 0;
1785         }
1786
1787         this_wc->flags = WF_DELETE;
1788         if (logfs_block(ipage)->partial)
1789                 this_wc->flags |= WF_WRITE;
1790
1791         return logfs_write_i0(inode, ipage, this_wc);
1792 }
1793
1794 static int logfs_truncate_rec(struct inode *inode, u64 size)
1795 {
1796         struct logfs_inode *li = logfs_inode(inode);
1797         struct write_control wc = {
1798                 .ofs = li->li_data[INDIRECT_INDEX],
1799         };
1800         struct page *page;
1801         int err;
1802
1803         alloc_inode_block(inode);
1804
1805         if (!wc.ofs)
1806                 return 0;
1807
1808         page = logfs_get_write_page(inode, 0, LEVEL(li->li_height));
1809         if (!page)
1810                 return -ENOMEM;
1811
1812         err = __logfs_truncate_rec(inode, page, &wc, size);
1813         logfs_put_write_page(page);
1814         if (err)
1815                 return err;
1816
1817         if (li->li_data[INDIRECT_INDEX] != wc.ofs)
1818                 li->li_data[INDIRECT_INDEX] = wc.ofs;
1819         return 0;
1820 }
1821
1822 static int __logfs_truncate(struct inode *inode, u64 size)
1823 {
1824         int ret;
1825
1826         if (size >= logfs_factor(logfs_inode(inode)->li_height))
1827                 return 0;
1828
1829         ret = logfs_truncate_rec(inode, size);
1830         if (ret)
1831                 return ret;
1832
1833         return logfs_truncate_direct(inode, size);
1834 }
1835
1836 int logfs_truncate(struct inode *inode, u64 size)
1837 {
1838         struct super_block *sb = inode->i_sb;
1839         int err;
1840
1841         logfs_get_wblocks(sb, NULL, 1);
1842         err = __logfs_truncate(inode, size);
1843         if (!err)
1844                 err = __logfs_write_inode(inode, 0);
1845         logfs_put_wblocks(sb, NULL, 1);
1846
1847         if (!err)
1848                 err = vmtruncate(inode, size);
1849
1850         /* I don't trust error recovery yet. */
1851         WARN_ON(err);
1852         return err;
1853 }
1854
1855 static void move_page_to_inode(struct inode *inode, struct page *page)
1856 {
1857         struct logfs_inode *li = logfs_inode(inode);
1858         struct logfs_block *block = logfs_block(page);
1859
1860         if (!block)
1861                 return;
1862
1863         log_blockmove("move_page_to_inode(%llx, %llx, %x)\n",
1864                         block->ino, block->bix, block->level);
1865         BUG_ON(li->li_block);
1866         block->ops = &inode_block_ops;
1867         block->inode = inode;
1868         li->li_block = block;
1869
1870         block->page = NULL;
1871         page->private = 0;
1872         ClearPagePrivate(page);
1873 }
1874
1875 static void move_inode_to_page(struct page *page, struct inode *inode)
1876 {
1877         struct logfs_inode *li = logfs_inode(inode);
1878         struct logfs_block *block = li->li_block;
1879
1880         if (!block)
1881                 return;
1882
1883         log_blockmove("move_inode_to_page(%llx, %llx, %x)\n",
1884                         block->ino, block->bix, block->level);
1885         BUG_ON(PagePrivate(page));
1886         block->ops = &indirect_block_ops;
1887         block->page = page;
1888         page->private = (unsigned long)block;
1889         SetPagePrivate(page);
1890
1891         block->inode = NULL;
1892         li->li_block = NULL;
1893 }
1894
1895 int logfs_read_inode(struct inode *inode)
1896 {
1897         struct super_block *sb = inode->i_sb;
1898         struct logfs_super *super = logfs_super(sb);
1899         struct inode *master_inode = super->s_master_inode;
1900         struct page *page;
1901         struct logfs_disk_inode *di;
1902         u64 ino = inode->i_ino;
1903
1904         if (ino << sb->s_blocksize_bits > i_size_read(master_inode))
1905                 return -ENODATA;
1906         if (!logfs_exist_block(master_inode, ino))
1907                 return -ENODATA;
1908
1909         page = read_cache_page(master_inode->i_mapping, ino,
1910                         (filler_t *)logfs_readpage, NULL);
1911         if (IS_ERR(page))
1912                 return PTR_ERR(page);
1913
1914         di = kmap_atomic(page, KM_USER0);
1915         logfs_disk_to_inode(di, inode);
1916         kunmap_atomic(di, KM_USER0);
1917         move_page_to_inode(inode, page);
1918         page_cache_release(page);
1919         return 0;
1920 }
1921
1922 /* Caller must logfs_put_write_page(page); */
1923 static struct page *inode_to_page(struct inode *inode)
1924 {
1925         struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode;
1926         struct logfs_disk_inode *di;
1927         struct page *page;
1928
1929         BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
1930
1931         page = logfs_get_write_page(master_inode, inode->i_ino, 0);
1932         if (!page)
1933                 return NULL;
1934
1935         di = kmap_atomic(page, KM_USER0);
1936         logfs_inode_to_disk(inode, di);
1937         kunmap_atomic(di, KM_USER0);
1938         move_inode_to_page(page, inode);
1939         return page;
1940 }
1941
1942 /* Cheaper version of write_inode.  All changes are concealed in
1943  * aliases, which are moved back.  No write to the medium happens.
1944  */
1945 void logfs_clear_inode(struct inode *inode)
1946 {
1947         struct super_block *sb = inode->i_sb;
1948         struct logfs_inode *li = logfs_inode(inode);
1949         struct logfs_block *block = li->li_block;
1950         struct page *page;
1951
1952         /* Only deleted files may be dirty at this point */
1953         BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink);
1954         if (!block)
1955                 return;
1956         if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) {
1957                 block->ops->free_block(inode->i_sb, block);
1958                 return;
1959         }
1960
1961         BUG_ON(inode->i_ino < LOGFS_RESERVED_INOS);
1962         page = inode_to_page(inode);
1963         BUG_ON(!page); /* FIXME: Use emergency page */
1964         logfs_put_write_page(page);
1965 }
1966
1967 static int do_write_inode(struct inode *inode)
1968 {
1969         struct super_block *sb = inode->i_sb;
1970         struct inode *master_inode = logfs_super(sb)->s_master_inode;
1971         loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits;
1972         struct page *page;
1973         int err;
1974
1975         BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
1976         /* FIXME: lock inode */
1977
1978         if (i_size_read(master_inode) < size)
1979                 i_size_write(master_inode, size);
1980
1981         /* TODO: Tell vfs this inode is clean now */
1982
1983         page = inode_to_page(inode);
1984         if (!page)
1985                 return -ENOMEM;
1986
1987         /* FIXME: transaction is part of logfs_block now.  Is that enough? */
1988         err = logfs_write_buf(master_inode, page, 0);
1989         logfs_put_write_page(page);
1990         return err;
1991 }
1992
1993 static void logfs_mod_segment_entry(struct super_block *sb, u32 segno,
1994                 int write,
1995                 void (*change_se)(struct logfs_segment_entry *, long),
1996                 long arg)
1997 {
1998         struct logfs_super *super = logfs_super(sb);
1999         struct inode *inode;
2000         struct page *page;
2001         struct logfs_segment_entry *se;
2002         pgoff_t page_no;
2003         int child_no;
2004
2005         page_no = segno >> (sb->s_blocksize_bits - 3);
2006         child_no = segno & ((sb->s_blocksize >> 3) - 1);
2007
2008         inode = super->s_segfile_inode;
2009         page = logfs_get_write_page(inode, page_no, 0);
2010         BUG_ON(!page); /* FIXME: We need some reserve page for this case */
2011         if (!PageUptodate(page))
2012                 logfs_read_block(inode, page, WRITE);
2013
2014         if (write)
2015                 alloc_indirect_block(inode, page, 0);
2016         se = kmap_atomic(page, KM_USER0);
2017         change_se(se + child_no, arg);
2018         if (write) {
2019                 logfs_set_alias(sb, logfs_block(page), child_no);
2020                 BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize);
2021         }
2022         kunmap_atomic(se, KM_USER0);
2023
2024         logfs_put_write_page(page);
2025 }
2026
2027 static void __get_segment_entry(struct logfs_segment_entry *se, long _target)
2028 {
2029         struct logfs_segment_entry *target = (void *)_target;
2030
2031         *target = *se;
2032 }
2033
2034 void logfs_get_segment_entry(struct super_block *sb, u32 segno,
2035                 struct logfs_segment_entry *se)
2036 {
2037         logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se);
2038 }
2039
2040 static void __set_segment_used(struct logfs_segment_entry *se, long increment)
2041 {
2042         u32 valid;
2043
2044         valid = be32_to_cpu(se->valid);
2045         valid += increment;
2046         se->valid = cpu_to_be32(valid);
2047 }
2048
2049 void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment)
2050 {
2051         struct logfs_super *super = logfs_super(sb);
2052         u32 segno = ofs >> super->s_segshift;
2053
2054         if (!increment)
2055                 return;
2056
2057         logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment);
2058 }
2059
2060 static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level)
2061 {
2062         se->ec_level = cpu_to_be32(ec_level);
2063 }
2064
2065 void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
2066                 gc_level_t gc_level)
2067 {
2068         u32 ec_level = ec << 4 | (__force u8)gc_level;
2069
2070         logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level);
2071 }
2072
2073 static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore)
2074 {
2075         se->valid = cpu_to_be32(RESERVED);
2076 }
2077
2078 void logfs_set_segment_reserved(struct super_block *sb, u32 segno)
2079 {
2080         logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0);
2081 }
2082
2083 static void __set_segment_unreserved(struct logfs_segment_entry *se,
2084                 long ec_level)
2085 {
2086         se->valid = 0;
2087         se->ec_level = cpu_to_be32(ec_level);
2088 }
2089
2090 void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec)
2091 {
2092         u32 ec_level = ec << 4;
2093
2094         logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved,
2095                         ec_level);
2096 }
2097
2098 int __logfs_write_inode(struct inode *inode, long flags)
2099 {
2100         struct super_block *sb = inode->i_sb;
2101         int ret;
2102
2103         logfs_get_wblocks(sb, NULL, flags & WF_LOCK);
2104         ret = do_write_inode(inode);
2105         logfs_put_wblocks(sb, NULL, flags & WF_LOCK);
2106         return ret;
2107 }
2108
2109 static int do_delete_inode(struct inode *inode)
2110 {
2111         struct super_block *sb = inode->i_sb;
2112         struct inode *master_inode = logfs_super(sb)->s_master_inode;
2113         struct page *page;
2114         int ret;
2115
2116         page = logfs_get_write_page(master_inode, inode->i_ino, 0);
2117         if (!page)
2118                 return -ENOMEM;
2119
2120         move_inode_to_page(page, inode);
2121
2122         logfs_get_wblocks(sb, page, 1);
2123         ret = __logfs_delete(master_inode, page);
2124         logfs_put_wblocks(sb, page, 1);
2125
2126         logfs_put_write_page(page);
2127         return ret;
2128 }
2129
2130 /*
2131  * ZOMBIE inodes have already been deleted before and should remain dead,
2132  * if it weren't for valid checking.  No need to kill them again here.
2133  */
2134 void logfs_delete_inode(struct inode *inode)
2135 {
2136         struct logfs_inode *li = logfs_inode(inode);
2137
2138         if (!(li->li_flags & LOGFS_IF_ZOMBIE)) {
2139                 li->li_flags |= LOGFS_IF_ZOMBIE;
2140                 if (i_size_read(inode) > 0)
2141                         logfs_truncate(inode, 0);
2142                 do_delete_inode(inode);
2143         }
2144         truncate_inode_pages(&inode->i_data, 0);
2145         clear_inode(inode);
2146 }
2147
2148 void btree_write_block(struct logfs_block *block)
2149 {
2150         struct inode *inode;
2151         struct page *page;
2152         int err, cookie;
2153
2154         inode = logfs_safe_iget(block->sb, block->ino, &cookie);
2155         page = logfs_get_write_page(inode, block->bix, block->level);
2156
2157         err = logfs_readpage_nolock(page);
2158         BUG_ON(err);
2159         BUG_ON(!PagePrivate(page));
2160         BUG_ON(logfs_block(page) != block);
2161         err = __logfs_write_buf(inode, page, 0);
2162         BUG_ON(err);
2163         BUG_ON(PagePrivate(page) || page->private);
2164
2165         logfs_put_write_page(page);
2166         logfs_safe_iput(inode, cookie);
2167 }
2168
2169 /**
2170  * logfs_inode_write - write inode or dentry objects
2171  *
2172  * @inode:              parent inode (ifile or directory)
2173  * @buf:                object to write (inode or dentry)
2174  * @n:                  object size
2175  * @_pos:               object number (file position in blocks/objects)
2176  * @flags:              write flags
2177  * @lock:               0 if write lock is already taken, 1 otherwise
2178  * @shadow_tree:        shadow below this inode
2179  *
2180  * FIXME: All caller of this put a 200-300 byte variable on the stack,
2181  * only to call here and do a memcpy from that stack variable.  A good
2182  * example of wasted performance and stack space.
2183  */
2184 int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
2185                 loff_t bix, long flags, struct shadow_tree *shadow_tree)
2186 {
2187         loff_t pos = bix << inode->i_sb->s_blocksize_bits;
2188         int err;
2189         struct page *page;
2190         void *pagebuf;
2191
2192         BUG_ON(pos & (LOGFS_BLOCKSIZE-1));
2193         BUG_ON(count > LOGFS_BLOCKSIZE);
2194         page = logfs_get_write_page(inode, bix, 0);
2195         if (!page)
2196                 return -ENOMEM;
2197
2198         pagebuf = kmap_atomic(page, KM_USER0);
2199         memcpy(pagebuf, buf, count);
2200         flush_dcache_page(page);
2201         kunmap_atomic(pagebuf, KM_USER0);
2202
2203         if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE)
2204                 i_size_write(inode, pos + LOGFS_BLOCKSIZE);
2205
2206         err = logfs_write_buf(inode, page, flags);
2207         logfs_put_write_page(page);
2208         return err;
2209 }
2210
2211 int logfs_open_segfile(struct super_block *sb)
2212 {
2213         struct logfs_super *super = logfs_super(sb);
2214         struct inode *inode;
2215
2216         inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE);
2217         if (IS_ERR(inode))
2218                 return PTR_ERR(inode);
2219         super->s_segfile_inode = inode;
2220         return 0;
2221 }
2222
2223 int logfs_init_rw(struct super_block *sb)
2224 {
2225         struct logfs_super *super = logfs_super(sb);
2226         int min_fill = 3 * super->s_no_blocks;
2227
2228         INIT_LIST_HEAD(&super->s_object_alias);
2229         mutex_init(&super->s_write_mutex);
2230         super->s_block_pool = mempool_create_kmalloc_pool(min_fill,
2231                         sizeof(struct logfs_block));
2232         super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill,
2233                         sizeof(struct logfs_shadow));
2234         return 0;
2235 }
2236
2237 void logfs_cleanup_rw(struct super_block *sb)
2238 {
2239         struct logfs_super *super = logfs_super(sb);
2240
2241         destroy_meta_inode(super->s_segfile_inode);
2242         if (super->s_block_pool)
2243                 mempool_destroy(super->s_block_pool);
2244         if (super->s_shadow_pool)
2245                 mempool_destroy(super->s_shadow_pool);
2246 }