linux/fs/ext3/inode.c
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   1/*
   2 *  linux/fs/ext3/inode.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  from
  10 *
  11 *  linux/fs/minix/inode.c
  12 *
  13 *  Copyright (C) 1991, 1992  Linus Torvalds
  14 *
  15 *  Goal-directed block allocation by Stephen Tweedie
  16 *      (sct@redhat.com), 1993, 1998
  17 *  Big-endian to little-endian byte-swapping/bitmaps by
  18 *        David S. Miller (davem@caip.rutgers.edu), 1995
  19 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  20 *      (jj@sunsite.ms.mff.cuni.cz)
  21 *
  22 *  Assorted race fixes, rewrite of ext3_get_block() by Al Viro, 2000
  23 */
  24
  25#include <linux/highuid.h>
  26#include <linux/quotaops.h>
  27#include <linux/writeback.h>
  28#include <linux/mpage.h>
  29#include <linux/namei.h>
  30#include "ext3.h"
  31#include "xattr.h"
  32#include "acl.h"
  33
  34static int ext3_writepage_trans_blocks(struct inode *inode);
  35static int ext3_block_truncate_page(struct inode *inode, loff_t from);
  36
  37/*
  38 * Test whether an inode is a fast symlink.
  39 */
  40static int ext3_inode_is_fast_symlink(struct inode *inode)
  41{
  42        int ea_blocks = EXT3_I(inode)->i_file_acl ?
  43                (inode->i_sb->s_blocksize >> 9) : 0;
  44
  45        return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
  46}
  47
  48/*
  49 * The ext3 forget function must perform a revoke if we are freeing data
  50 * which has been journaled.  Metadata (eg. indirect blocks) must be
  51 * revoked in all cases.
  52 *
  53 * "bh" may be NULL: a metadata block may have been freed from memory
  54 * but there may still be a record of it in the journal, and that record
  55 * still needs to be revoked.
  56 */
  57int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
  58                        struct buffer_head *bh, ext3_fsblk_t blocknr)
  59{
  60        int err;
  61
  62        might_sleep();
  63
  64        trace_ext3_forget(inode, is_metadata, blocknr);
  65        BUFFER_TRACE(bh, "enter");
  66
  67        jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
  68                  "data mode %lx\n",
  69                  bh, is_metadata, inode->i_mode,
  70                  test_opt(inode->i_sb, DATA_FLAGS));
  71
  72        /* Never use the revoke function if we are doing full data
  73         * journaling: there is no need to, and a V1 superblock won't
  74         * support it.  Otherwise, only skip the revoke on un-journaled
  75         * data blocks. */
  76
  77        if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
  78            (!is_metadata && !ext3_should_journal_data(inode))) {
  79                if (bh) {
  80                        BUFFER_TRACE(bh, "call journal_forget");
  81                        return ext3_journal_forget(handle, bh);
  82                }
  83                return 0;
  84        }
  85
  86        /*
  87         * data!=journal && (is_metadata || should_journal_data(inode))
  88         */
  89        BUFFER_TRACE(bh, "call ext3_journal_revoke");
  90        err = ext3_journal_revoke(handle, blocknr, bh);
  91        if (err)
  92                ext3_abort(inode->i_sb, __func__,
  93                           "error %d when attempting revoke", err);
  94        BUFFER_TRACE(bh, "exit");
  95        return err;
  96}
  97
  98/*
  99 * Work out how many blocks we need to proceed with the next chunk of a
 100 * truncate transaction.
 101 */
 102static unsigned long blocks_for_truncate(struct inode *inode)
 103{
 104        unsigned long needed;
 105
 106        needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
 107
 108        /* Give ourselves just enough room to cope with inodes in which
 109         * i_blocks is corrupt: we've seen disk corruptions in the past
 110         * which resulted in random data in an inode which looked enough
 111         * like a regular file for ext3 to try to delete it.  Things
 112         * will go a bit crazy if that happens, but at least we should
 113         * try not to panic the whole kernel. */
 114        if (needed < 2)
 115                needed = 2;
 116
 117        /* But we need to bound the transaction so we don't overflow the
 118         * journal. */
 119        if (needed > EXT3_MAX_TRANS_DATA)
 120                needed = EXT3_MAX_TRANS_DATA;
 121
 122        return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
 123}
 124
 125/*
 126 * Truncate transactions can be complex and absolutely huge.  So we need to
 127 * be able to restart the transaction at a conventient checkpoint to make
 128 * sure we don't overflow the journal.
 129 *
 130 * start_transaction gets us a new handle for a truncate transaction,
 131 * and extend_transaction tries to extend the existing one a bit.  If
 132 * extend fails, we need to propagate the failure up and restart the
 133 * transaction in the top-level truncate loop. --sct
 134 */
 135static handle_t *start_transaction(struct inode *inode)
 136{
 137        handle_t *result;
 138
 139        result = ext3_journal_start(inode, blocks_for_truncate(inode));
 140        if (!IS_ERR(result))
 141                return result;
 142
 143        ext3_std_error(inode->i_sb, PTR_ERR(result));
 144        return result;
 145}
 146
 147/*
 148 * Try to extend this transaction for the purposes of truncation.
 149 *
 150 * Returns 0 if we managed to create more room.  If we can't create more
 151 * room, and the transaction must be restarted we return 1.
 152 */
 153static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
 154{
 155        if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
 156                return 0;
 157        if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
 158                return 0;
 159        return 1;
 160}
 161
 162/*
 163 * Restart the transaction associated with *handle.  This does a commit,
 164 * so before we call here everything must be consistently dirtied against
 165 * this transaction.
 166 */
 167static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
 168{
 169        int ret;
 170
 171        jbd_debug(2, "restarting handle %p\n", handle);
 172        /*
 173         * Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
 174         * At this moment, get_block can be called only for blocks inside
 175         * i_size since page cache has been already dropped and writes are
 176         * blocked by i_mutex. So we can safely drop the truncate_mutex.
 177         */
 178        mutex_unlock(&EXT3_I(inode)->truncate_mutex);
 179        ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
 180        mutex_lock(&EXT3_I(inode)->truncate_mutex);
 181        return ret;
 182}
 183
 184/*
 185 * Called at inode eviction from icache
 186 */
 187void ext3_evict_inode (struct inode *inode)
 188{
 189        struct ext3_inode_info *ei = EXT3_I(inode);
 190        struct ext3_block_alloc_info *rsv;
 191        handle_t *handle;
 192        int want_delete = 0;
 193
 194        trace_ext3_evict_inode(inode);
 195        if (!inode->i_nlink && !is_bad_inode(inode)) {
 196                dquot_initialize(inode);
 197                want_delete = 1;
 198        }
 199
 200        /*
 201         * When journalling data dirty buffers are tracked only in the journal.
 202         * So although mm thinks everything is clean and ready for reaping the
 203         * inode might still have some pages to write in the running
 204         * transaction or waiting to be checkpointed. Thus calling
 205         * journal_invalidatepage() (via truncate_inode_pages()) to discard
 206         * these buffers can cause data loss. Also even if we did not discard
 207         * these buffers, we would have no way to find them after the inode
 208         * is reaped and thus user could see stale data if he tries to read
 209         * them before the transaction is checkpointed. So be careful and
 210         * force everything to disk here... We use ei->i_datasync_tid to
 211         * store the newest transaction containing inode's data.
 212         *
 213         * Note that directories do not have this problem because they don't
 214         * use page cache.
 215         *
 216         * The s_journal check handles the case when ext3_get_journal() fails
 217         * and puts the journal inode.
 218         */
 219        if (inode->i_nlink && ext3_should_journal_data(inode) &&
 220            EXT3_SB(inode->i_sb)->s_journal &&
 221            (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
 222                tid_t commit_tid = atomic_read(&ei->i_datasync_tid);
 223                journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
 224
 225                log_start_commit(journal, commit_tid);
 226                log_wait_commit(journal, commit_tid);
 227                filemap_write_and_wait(&inode->i_data);
 228        }
 229        truncate_inode_pages(&inode->i_data, 0);
 230
 231        ext3_discard_reservation(inode);
 232        rsv = ei->i_block_alloc_info;
 233        ei->i_block_alloc_info = NULL;
 234        if (unlikely(rsv))
 235                kfree(rsv);
 236
 237        if (!want_delete)
 238                goto no_delete;
 239
 240        handle = start_transaction(inode);
 241        if (IS_ERR(handle)) {
 242                /*
 243                 * If we're going to skip the normal cleanup, we still need to
 244                 * make sure that the in-core orphan linked list is properly
 245                 * cleaned up.
 246                 */
 247                ext3_orphan_del(NULL, inode);
 248                goto no_delete;
 249        }
 250
 251        if (IS_SYNC(inode))
 252                handle->h_sync = 1;
 253        inode->i_size = 0;
 254        if (inode->i_blocks)
 255                ext3_truncate(inode);
 256        /*
 257         * Kill off the orphan record created when the inode lost the last
 258         * link.  Note that ext3_orphan_del() has to be able to cope with the
 259         * deletion of a non-existent orphan - ext3_truncate() could
 260         * have removed the record.
 261         */
 262        ext3_orphan_del(handle, inode);
 263        ei->i_dtime = get_seconds();
 264
 265        /*
 266         * One subtle ordering requirement: if anything has gone wrong
 267         * (transaction abort, IO errors, whatever), then we can still
 268         * do these next steps (the fs will already have been marked as
 269         * having errors), but we can't free the inode if the mark_dirty
 270         * fails.
 271         */
 272        if (ext3_mark_inode_dirty(handle, inode)) {
 273                /* If that failed, just dquot_drop() and be done with that */
 274                dquot_drop(inode);
 275                clear_inode(inode);
 276        } else {
 277                ext3_xattr_delete_inode(handle, inode);
 278                dquot_free_inode(inode);
 279                dquot_drop(inode);
 280                clear_inode(inode);
 281                ext3_free_inode(handle, inode);
 282        }
 283        ext3_journal_stop(handle);
 284        return;
 285no_delete:
 286        clear_inode(inode);
 287        dquot_drop(inode);
 288}
 289
 290typedef struct {
 291        __le32  *p;
 292        __le32  key;
 293        struct buffer_head *bh;
 294} Indirect;
 295
 296static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
 297{
 298        p->key = *(p->p = v);
 299        p->bh = bh;
 300}
 301
 302static int verify_chain(Indirect *from, Indirect *to)
 303{
 304        while (from <= to && from->key == *from->p)
 305                from++;
 306        return (from > to);
 307}
 308
 309/**
 310 *      ext3_block_to_path - parse the block number into array of offsets
 311 *      @inode: inode in question (we are only interested in its superblock)
 312 *      @i_block: block number to be parsed
 313 *      @offsets: array to store the offsets in
 314 *      @boundary: set this non-zero if the referred-to block is likely to be
 315 *             followed (on disk) by an indirect block.
 316 *
 317 *      To store the locations of file's data ext3 uses a data structure common
 318 *      for UNIX filesystems - tree of pointers anchored in the inode, with
 319 *      data blocks at leaves and indirect blocks in intermediate nodes.
 320 *      This function translates the block number into path in that tree -
 321 *      return value is the path length and @offsets[n] is the offset of
 322 *      pointer to (n+1)th node in the nth one. If @block is out of range
 323 *      (negative or too large) warning is printed and zero returned.
 324 *
 325 *      Note: function doesn't find node addresses, so no IO is needed. All
 326 *      we need to know is the capacity of indirect blocks (taken from the
 327 *      inode->i_sb).
 328 */
 329
 330/*
 331 * Portability note: the last comparison (check that we fit into triple
 332 * indirect block) is spelled differently, because otherwise on an
 333 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 334 * if our filesystem had 8Kb blocks. We might use long long, but that would
 335 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 336 * i_block would have to be negative in the very beginning, so we would not
 337 * get there at all.
 338 */
 339
 340static int ext3_block_to_path(struct inode *inode,
 341                        long i_block, int offsets[4], int *boundary)
 342{
 343        int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
 344        int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
 345        const long direct_blocks = EXT3_NDIR_BLOCKS,
 346                indirect_blocks = ptrs,
 347                double_blocks = (1 << (ptrs_bits * 2));
 348        int n = 0;
 349        int final = 0;
 350
 351        if (i_block < 0) {
 352                ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
 353        } else if (i_block < direct_blocks) {
 354                offsets[n++] = i_block;
 355                final = direct_blocks;
 356        } else if ( (i_block -= direct_blocks) < indirect_blocks) {
 357                offsets[n++] = EXT3_IND_BLOCK;
 358                offsets[n++] = i_block;
 359                final = ptrs;
 360        } else if ((i_block -= indirect_blocks) < double_blocks) {
 361                offsets[n++] = EXT3_DIND_BLOCK;
 362                offsets[n++] = i_block >> ptrs_bits;
 363                offsets[n++] = i_block & (ptrs - 1);
 364                final = ptrs;
 365        } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
 366                offsets[n++] = EXT3_TIND_BLOCK;
 367                offsets[n++] = i_block >> (ptrs_bits * 2);
 368                offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
 369                offsets[n++] = i_block & (ptrs - 1);
 370                final = ptrs;
 371        } else {
 372                ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
 373        }
 374        if (boundary)
 375                *boundary = final - 1 - (i_block & (ptrs - 1));
 376        return n;
 377}
 378
 379/**
 380 *      ext3_get_branch - read the chain of indirect blocks leading to data
 381 *      @inode: inode in question
 382 *      @depth: depth of the chain (1 - direct pointer, etc.)
 383 *      @offsets: offsets of pointers in inode/indirect blocks
 384 *      @chain: place to store the result
 385 *      @err: here we store the error value
 386 *
 387 *      Function fills the array of triples <key, p, bh> and returns %NULL
 388 *      if everything went OK or the pointer to the last filled triple
 389 *      (incomplete one) otherwise. Upon the return chain[i].key contains
 390 *      the number of (i+1)-th block in the chain (as it is stored in memory,
 391 *      i.e. little-endian 32-bit), chain[i].p contains the address of that
 392 *      number (it points into struct inode for i==0 and into the bh->b_data
 393 *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 394 *      block for i>0 and NULL for i==0. In other words, it holds the block
 395 *      numbers of the chain, addresses they were taken from (and where we can
 396 *      verify that chain did not change) and buffer_heads hosting these
 397 *      numbers.
 398 *
 399 *      Function stops when it stumbles upon zero pointer (absent block)
 400 *              (pointer to last triple returned, *@err == 0)
 401 *      or when it gets an IO error reading an indirect block
 402 *              (ditto, *@err == -EIO)
 403 *      or when it notices that chain had been changed while it was reading
 404 *              (ditto, *@err == -EAGAIN)
 405 *      or when it reads all @depth-1 indirect blocks successfully and finds
 406 *      the whole chain, all way to the data (returns %NULL, *err == 0).
 407 */
 408static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
 409                                 Indirect chain[4], int *err)
 410{
 411        struct super_block *sb = inode->i_sb;
 412        Indirect *p = chain;
 413        struct buffer_head *bh;
 414
 415        *err = 0;
 416        /* i_data is not going away, no lock needed */
 417        add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
 418        if (!p->key)
 419                goto no_block;
 420        while (--depth) {
 421                bh = sb_bread(sb, le32_to_cpu(p->key));
 422                if (!bh)
 423                        goto failure;
 424                /* Reader: pointers */
 425                if (!verify_chain(chain, p))
 426                        goto changed;
 427                add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
 428                /* Reader: end */
 429                if (!p->key)
 430                        goto no_block;
 431        }
 432        return NULL;
 433
 434changed:
 435        brelse(bh);
 436        *err = -EAGAIN;
 437        goto no_block;
 438failure:
 439        *err = -EIO;
 440no_block:
 441        return p;
 442}
 443
 444/**
 445 *      ext3_find_near - find a place for allocation with sufficient locality
 446 *      @inode: owner
 447 *      @ind: descriptor of indirect block.
 448 *
 449 *      This function returns the preferred place for block allocation.
 450 *      It is used when heuristic for sequential allocation fails.
 451 *      Rules are:
 452 *        + if there is a block to the left of our position - allocate near it.
 453 *        + if pointer will live in indirect block - allocate near that block.
 454 *        + if pointer will live in inode - allocate in the same
 455 *          cylinder group.
 456 *
 457 * In the latter case we colour the starting block by the callers PID to
 458 * prevent it from clashing with concurrent allocations for a different inode
 459 * in the same block group.   The PID is used here so that functionally related
 460 * files will be close-by on-disk.
 461 *
 462 *      Caller must make sure that @ind is valid and will stay that way.
 463 */
 464static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
 465{
 466        struct ext3_inode_info *ei = EXT3_I(inode);
 467        __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
 468        __le32 *p;
 469        ext3_fsblk_t bg_start;
 470        ext3_grpblk_t colour;
 471
 472        /* Try to find previous block */
 473        for (p = ind->p - 1; p >= start; p--) {
 474                if (*p)
 475                        return le32_to_cpu(*p);
 476        }
 477
 478        /* No such thing, so let's try location of indirect block */
 479        if (ind->bh)
 480                return ind->bh->b_blocknr;
 481
 482        /*
 483         * It is going to be referred to from the inode itself? OK, just put it
 484         * into the same cylinder group then.
 485         */
 486        bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
 487        colour = (current->pid % 16) *
 488                        (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 489        return bg_start + colour;
 490}
 491
 492/**
 493 *      ext3_find_goal - find a preferred place for allocation.
 494 *      @inode: owner
 495 *      @block:  block we want
 496 *      @partial: pointer to the last triple within a chain
 497 *
 498 *      Normally this function find the preferred place for block allocation,
 499 *      returns it.
 500 */
 501
 502static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
 503                                   Indirect *partial)
 504{
 505        struct ext3_block_alloc_info *block_i;
 506
 507        block_i =  EXT3_I(inode)->i_block_alloc_info;
 508
 509        /*
 510         * try the heuristic for sequential allocation,
 511         * failing that at least try to get decent locality.
 512         */
 513        if (block_i && (block == block_i->last_alloc_logical_block + 1)
 514                && (block_i->last_alloc_physical_block != 0)) {
 515                return block_i->last_alloc_physical_block + 1;
 516        }
 517
 518        return ext3_find_near(inode, partial);
 519}
 520
 521/**
 522 *      ext3_blks_to_allocate - Look up the block map and count the number
 523 *      of direct blocks need to be allocated for the given branch.
 524 *
 525 *      @branch: chain of indirect blocks
 526 *      @k: number of blocks need for indirect blocks
 527 *      @blks: number of data blocks to be mapped.
 528 *      @blocks_to_boundary:  the offset in the indirect block
 529 *
 530 *      return the total number of blocks to be allocate, including the
 531 *      direct and indirect blocks.
 532 */
 533static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
 534                int blocks_to_boundary)
 535{
 536        unsigned long count = 0;
 537
 538        /*
 539         * Simple case, [t,d]Indirect block(s) has not allocated yet
 540         * then it's clear blocks on that path have not allocated
 541         */
 542        if (k > 0) {
 543                /* right now we don't handle cross boundary allocation */
 544                if (blks < blocks_to_boundary + 1)
 545                        count += blks;
 546                else
 547                        count += blocks_to_boundary + 1;
 548                return count;
 549        }
 550
 551        count++;
 552        while (count < blks && count <= blocks_to_boundary &&
 553                le32_to_cpu(*(branch[0].p + count)) == 0) {
 554                count++;
 555        }
 556        return count;
 557}
 558
 559/**
 560 *      ext3_alloc_blocks - multiple allocate blocks needed for a branch
 561 *      @handle: handle for this transaction
 562 *      @inode: owner
 563 *      @goal: preferred place for allocation
 564 *      @indirect_blks: the number of blocks need to allocate for indirect
 565 *                      blocks
 566 *      @blks:  number of blocks need to allocated for direct blocks
 567 *      @new_blocks: on return it will store the new block numbers for
 568 *      the indirect blocks(if needed) and the first direct block,
 569 *      @err: here we store the error value
 570 *
 571 *      return the number of direct blocks allocated
 572 */
 573static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
 574                        ext3_fsblk_t goal, int indirect_blks, int blks,
 575                        ext3_fsblk_t new_blocks[4], int *err)
 576{
 577        int target, i;
 578        unsigned long count = 0;
 579        int index = 0;
 580        ext3_fsblk_t current_block = 0;
 581        int ret = 0;
 582
 583        /*
 584         * Here we try to allocate the requested multiple blocks at once,
 585         * on a best-effort basis.
 586         * To build a branch, we should allocate blocks for
 587         * the indirect blocks(if not allocated yet), and at least
 588         * the first direct block of this branch.  That's the
 589         * minimum number of blocks need to allocate(required)
 590         */
 591        target = blks + indirect_blks;
 592
 593        while (1) {
 594                count = target;
 595                /* allocating blocks for indirect blocks and direct blocks */
 596                current_block = ext3_new_blocks(handle,inode,goal,&count,err);
 597                if (*err)
 598                        goto failed_out;
 599
 600                target -= count;
 601                /* allocate blocks for indirect blocks */
 602                while (index < indirect_blks && count) {
 603                        new_blocks[index++] = current_block++;
 604                        count--;
 605                }
 606
 607                if (count > 0)
 608                        break;
 609        }
 610
 611        /* save the new block number for the first direct block */
 612        new_blocks[index] = current_block;
 613
 614        /* total number of blocks allocated for direct blocks */
 615        ret = count;
 616        *err = 0;
 617        return ret;
 618failed_out:
 619        for (i = 0; i <index; i++)
 620                ext3_free_blocks(handle, inode, new_blocks[i], 1);
 621        return ret;
 622}
 623
 624/**
 625 *      ext3_alloc_branch - allocate and set up a chain of blocks.
 626 *      @handle: handle for this transaction
 627 *      @inode: owner
 628 *      @indirect_blks: number of allocated indirect blocks
 629 *      @blks: number of allocated direct blocks
 630 *      @goal: preferred place for allocation
 631 *      @offsets: offsets (in the blocks) to store the pointers to next.
 632 *      @branch: place to store the chain in.
 633 *
 634 *      This function allocates blocks, zeroes out all but the last one,
 635 *      links them into chain and (if we are synchronous) writes them to disk.
 636 *      In other words, it prepares a branch that can be spliced onto the
 637 *      inode. It stores the information about that chain in the branch[], in
 638 *      the same format as ext3_get_branch() would do. We are calling it after
 639 *      we had read the existing part of chain and partial points to the last
 640 *      triple of that (one with zero ->key). Upon the exit we have the same
 641 *      picture as after the successful ext3_get_block(), except that in one
 642 *      place chain is disconnected - *branch->p is still zero (we did not
 643 *      set the last link), but branch->key contains the number that should
 644 *      be placed into *branch->p to fill that gap.
 645 *
 646 *      If allocation fails we free all blocks we've allocated (and forget
 647 *      their buffer_heads) and return the error value the from failed
 648 *      ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 649 *      as described above and return 0.
 650 */
 651static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
 652                        int indirect_blks, int *blks, ext3_fsblk_t goal,
 653                        int *offsets, Indirect *branch)
 654{
 655        int blocksize = inode->i_sb->s_blocksize;
 656        int i, n = 0;
 657        int err = 0;
 658        struct buffer_head *bh;
 659        int num;
 660        ext3_fsblk_t new_blocks[4];
 661        ext3_fsblk_t current_block;
 662
 663        num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
 664                                *blks, new_blocks, &err);
 665        if (err)
 666                return err;
 667
 668        branch[0].key = cpu_to_le32(new_blocks[0]);
 669        /*
 670         * metadata blocks and data blocks are allocated.
 671         */
 672        for (n = 1; n <= indirect_blks;  n++) {
 673                /*
 674                 * Get buffer_head for parent block, zero it out
 675                 * and set the pointer to new one, then send
 676                 * parent to disk.
 677                 */
 678                bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 679                branch[n].bh = bh;
 680                lock_buffer(bh);
 681                BUFFER_TRACE(bh, "call get_create_access");
 682                err = ext3_journal_get_create_access(handle, bh);
 683                if (err) {
 684                        unlock_buffer(bh);
 685                        brelse(bh);
 686                        goto failed;
 687                }
 688
 689                memset(bh->b_data, 0, blocksize);
 690                branch[n].p = (__le32 *) bh->b_data + offsets[n];
 691                branch[n].key = cpu_to_le32(new_blocks[n]);
 692                *branch[n].p = branch[n].key;
 693                if ( n == indirect_blks) {
 694                        current_block = new_blocks[n];
 695                        /*
 696                         * End of chain, update the last new metablock of
 697                         * the chain to point to the new allocated
 698                         * data blocks numbers
 699                         */
 700                        for (i=1; i < num; i++)
 701                                *(branch[n].p + i) = cpu_to_le32(++current_block);
 702                }
 703                BUFFER_TRACE(bh, "marking uptodate");
 704                set_buffer_uptodate(bh);
 705                unlock_buffer(bh);
 706
 707                BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
 708                err = ext3_journal_dirty_metadata(handle, bh);
 709                if (err)
 710                        goto failed;
 711        }
 712        *blks = num;
 713        return err;
 714failed:
 715        /* Allocation failed, free what we already allocated */
 716        for (i = 1; i <= n ; i++) {
 717                BUFFER_TRACE(branch[i].bh, "call journal_forget");
 718                ext3_journal_forget(handle, branch[i].bh);
 719        }
 720        for (i = 0; i <indirect_blks; i++)
 721                ext3_free_blocks(handle, inode, new_blocks[i], 1);
 722
 723        ext3_free_blocks(handle, inode, new_blocks[i], num);
 724
 725        return err;
 726}
 727
 728/**
 729 * ext3_splice_branch - splice the allocated branch onto inode.
 730 * @handle: handle for this transaction
 731 * @inode: owner
 732 * @block: (logical) number of block we are adding
 733 * @where: location of missing link
 734 * @num:   number of indirect blocks we are adding
 735 * @blks:  number of direct blocks we are adding
 736 *
 737 * This function fills the missing link and does all housekeeping needed in
 738 * inode (->i_blocks, etc.). In case of success we end up with the full
 739 * chain to new block and return 0.
 740 */
 741static int ext3_splice_branch(handle_t *handle, struct inode *inode,
 742                        long block, Indirect *where, int num, int blks)
 743{
 744        int i;
 745        int err = 0;
 746        struct ext3_block_alloc_info *block_i;
 747        ext3_fsblk_t current_block;
 748        struct ext3_inode_info *ei = EXT3_I(inode);
 749        struct timespec now;
 750
 751        block_i = ei->i_block_alloc_info;
 752        /*
 753         * If we're splicing into a [td]indirect block (as opposed to the
 754         * inode) then we need to get write access to the [td]indirect block
 755         * before the splice.
 756         */
 757        if (where->bh) {
 758                BUFFER_TRACE(where->bh, "get_write_access");
 759                err = ext3_journal_get_write_access(handle, where->bh);
 760                if (err)
 761                        goto err_out;
 762        }
 763        /* That's it */
 764
 765        *where->p = where->key;
 766
 767        /*
 768         * Update the host buffer_head or inode to point to more just allocated
 769         * direct blocks blocks
 770         */
 771        if (num == 0 && blks > 1) {
 772                current_block = le32_to_cpu(where->key) + 1;
 773                for (i = 1; i < blks; i++)
 774                        *(where->p + i ) = cpu_to_le32(current_block++);
 775        }
 776
 777        /*
 778         * update the most recently allocated logical & physical block
 779         * in i_block_alloc_info, to assist find the proper goal block for next
 780         * allocation
 781         */
 782        if (block_i) {
 783                block_i->last_alloc_logical_block = block + blks - 1;
 784                block_i->last_alloc_physical_block =
 785                                le32_to_cpu(where[num].key) + blks - 1;
 786        }
 787
 788        /* We are done with atomic stuff, now do the rest of housekeeping */
 789        now = CURRENT_TIME_SEC;
 790        if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) {
 791                inode->i_ctime = now;
 792                ext3_mark_inode_dirty(handle, inode);
 793        }
 794        /* ext3_mark_inode_dirty already updated i_sync_tid */
 795        atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
 796
 797        /* had we spliced it onto indirect block? */
 798        if (where->bh) {
 799                /*
 800                 * If we spliced it onto an indirect block, we haven't
 801                 * altered the inode.  Note however that if it is being spliced
 802                 * onto an indirect block at the very end of the file (the
 803                 * file is growing) then we *will* alter the inode to reflect
 804                 * the new i_size.  But that is not done here - it is done in
 805                 * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
 806                 */
 807                jbd_debug(5, "splicing indirect only\n");
 808                BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
 809                err = ext3_journal_dirty_metadata(handle, where->bh);
 810                if (err)
 811                        goto err_out;
 812        } else {
 813                /*
 814                 * OK, we spliced it into the inode itself on a direct block.
 815                 * Inode was dirtied above.
 816                 */
 817                jbd_debug(5, "splicing direct\n");
 818        }
 819        return err;
 820
 821err_out:
 822        for (i = 1; i <= num; i++) {
 823                BUFFER_TRACE(where[i].bh, "call journal_forget");
 824                ext3_journal_forget(handle, where[i].bh);
 825                ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
 826        }
 827        ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
 828
 829        return err;
 830}
 831
 832/*
 833 * Allocation strategy is simple: if we have to allocate something, we will
 834 * have to go the whole way to leaf. So let's do it before attaching anything
 835 * to tree, set linkage between the newborn blocks, write them if sync is
 836 * required, recheck the path, free and repeat if check fails, otherwise
 837 * set the last missing link (that will protect us from any truncate-generated
 838 * removals - all blocks on the path are immune now) and possibly force the
 839 * write on the parent block.
 840 * That has a nice additional property: no special recovery from the failed
 841 * allocations is needed - we simply release blocks and do not touch anything
 842 * reachable from inode.
 843 *
 844 * `handle' can be NULL if create == 0.
 845 *
 846 * The BKL may not be held on entry here.  Be sure to take it early.
 847 * return > 0, # of blocks mapped or allocated.
 848 * return = 0, if plain lookup failed.
 849 * return < 0, error case.
 850 */
 851int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
 852                sector_t iblock, unsigned long maxblocks,
 853                struct buffer_head *bh_result,
 854                int create)
 855{
 856        int err = -EIO;
 857        int offsets[4];
 858        Indirect chain[4];
 859        Indirect *partial;
 860        ext3_fsblk_t goal;
 861        int indirect_blks;
 862        int blocks_to_boundary = 0;
 863        int depth;
 864        struct ext3_inode_info *ei = EXT3_I(inode);
 865        int count = 0;
 866        ext3_fsblk_t first_block = 0;
 867
 868
 869        trace_ext3_get_blocks_enter(inode, iblock, maxblocks, create);
 870        J_ASSERT(handle != NULL || create == 0);
 871        depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 872
 873        if (depth == 0)
 874                goto out;
 875
 876        partial = ext3_get_branch(inode, depth, offsets, chain, &err);
 877
 878        /* Simplest case - block found, no allocation needed */
 879        if (!partial) {
 880                first_block = le32_to_cpu(chain[depth - 1].key);
 881                clear_buffer_new(bh_result);
 882                count++;
 883                /*map more blocks*/
 884                while (count < maxblocks && count <= blocks_to_boundary) {
 885                        ext3_fsblk_t blk;
 886
 887                        if (!verify_chain(chain, chain + depth - 1)) {
 888                                /*
 889                                 * Indirect block might be removed by
 890                                 * truncate while we were reading it.
 891                                 * Handling of that case: forget what we've
 892                                 * got now. Flag the err as EAGAIN, so it
 893                                 * will reread.
 894                                 */
 895                                err = -EAGAIN;
 896                                count = 0;
 897                                break;
 898                        }
 899                        blk = le32_to_cpu(*(chain[depth-1].p + count));
 900
 901                        if (blk == first_block + count)
 902                                count++;
 903                        else
 904                                break;
 905                }
 906                if (err != -EAGAIN)
 907                        goto got_it;
 908        }
 909
 910        /* Next simple case - plain lookup or failed read of indirect block */
 911        if (!create || err == -EIO)
 912                goto cleanup;
 913
 914        /*
 915         * Block out ext3_truncate while we alter the tree
 916         */
 917        mutex_lock(&ei->truncate_mutex);
 918
 919        /*
 920         * If the indirect block is missing while we are reading
 921         * the chain(ext3_get_branch() returns -EAGAIN err), or
 922         * if the chain has been changed after we grab the semaphore,
 923         * (either because another process truncated this branch, or
 924         * another get_block allocated this branch) re-grab the chain to see if
 925         * the request block has been allocated or not.
 926         *
 927         * Since we already block the truncate/other get_block
 928         * at this point, we will have the current copy of the chain when we
 929         * splice the branch into the tree.
 930         */
 931        if (err == -EAGAIN || !verify_chain(chain, partial)) {
 932                while (partial > chain) {
 933                        brelse(partial->bh);
 934                        partial--;
 935                }
 936                partial = ext3_get_branch(inode, depth, offsets, chain, &err);
 937                if (!partial) {
 938                        count++;
 939                        mutex_unlock(&ei->truncate_mutex);
 940                        if (err)
 941                                goto cleanup;
 942                        clear_buffer_new(bh_result);
 943                        goto got_it;
 944                }
 945        }
 946
 947        /*
 948         * Okay, we need to do block allocation.  Lazily initialize the block
 949         * allocation info here if necessary
 950        */
 951        if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
 952                ext3_init_block_alloc_info(inode);
 953
 954        goal = ext3_find_goal(inode, iblock, partial);
 955
 956        /* the number of blocks need to allocate for [d,t]indirect blocks */
 957        indirect_blks = (chain + depth) - partial - 1;
 958
 959        /*
 960         * Next look up the indirect map to count the totoal number of
 961         * direct blocks to allocate for this branch.
 962         */
 963        count = ext3_blks_to_allocate(partial, indirect_blks,
 964                                        maxblocks, blocks_to_boundary);
 965        err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
 966                                offsets + (partial - chain), partial);
 967
 968        /*
 969         * The ext3_splice_branch call will free and forget any buffers
 970         * on the new chain if there is a failure, but that risks using
 971         * up transaction credits, especially for bitmaps where the
 972         * credits cannot be returned.  Can we handle this somehow?  We
 973         * may need to return -EAGAIN upwards in the worst case.  --sct
 974         */
 975        if (!err)
 976                err = ext3_splice_branch(handle, inode, iblock,
 977                                        partial, indirect_blks, count);
 978        mutex_unlock(&ei->truncate_mutex);
 979        if (err)
 980                goto cleanup;
 981
 982        set_buffer_new(bh_result);
 983got_it:
 984        map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
 985        if (count > blocks_to_boundary)
 986                set_buffer_boundary(bh_result);
 987        err = count;
 988        /* Clean up and exit */
 989        partial = chain + depth - 1;    /* the whole chain */
 990cleanup:
 991        while (partial > chain) {
 992                BUFFER_TRACE(partial->bh, "call brelse");
 993                brelse(partial->bh);
 994                partial--;
 995        }
 996        BUFFER_TRACE(bh_result, "returned");
 997out:
 998        trace_ext3_get_blocks_exit(inode, iblock,
 999                                   depth ? le32_to_cpu(chain[depth-1].key) : 0,
1000                                   count, err);
1001        return err;
1002}
1003
1004/* Maximum number of blocks we map for direct IO at once. */
1005#define DIO_MAX_BLOCKS 4096
1006/*
1007 * Number of credits we need for writing DIO_MAX_BLOCKS:
1008 * We need sb + group descriptor + bitmap + inode -> 4
1009 * For B blocks with A block pointers per block we need:
1010 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
1011 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
1012 */
1013#define DIO_CREDITS 25
1014
1015static int ext3_get_block(struct inode *inode, sector_t iblock,
1016                        struct buffer_head *bh_result, int create)
1017{
1018        handle_t *handle = ext3_journal_current_handle();
1019        int ret = 0, started = 0;
1020        unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1021
1022        if (create && !handle) {        /* Direct IO write... */
1023                if (max_blocks > DIO_MAX_BLOCKS)
1024                        max_blocks = DIO_MAX_BLOCKS;
1025                handle = ext3_journal_start(inode, DIO_CREDITS +
1026                                EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
1027                if (IS_ERR(handle)) {
1028                        ret = PTR_ERR(handle);
1029                        goto out;
1030                }
1031                started = 1;
1032        }
1033
1034        ret = ext3_get_blocks_handle(handle, inode, iblock,
1035                                        max_blocks, bh_result, create);
1036        if (ret > 0) {
1037                bh_result->b_size = (ret << inode->i_blkbits);
1038                ret = 0;
1039        }
1040        if (started)
1041                ext3_journal_stop(handle);
1042out:
1043        return ret;
1044}
1045
1046int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1047                u64 start, u64 len)
1048{
1049        return generic_block_fiemap(inode, fieinfo, start, len,
1050                                    ext3_get_block);
1051}
1052
1053/*
1054 * `handle' can be NULL if create is zero
1055 */
1056struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
1057                                long block, int create, int *errp)
1058{
1059        struct buffer_head dummy;
1060        int fatal = 0, err;
1061
1062        J_ASSERT(handle != NULL || create == 0);
1063
1064        dummy.b_state = 0;
1065        dummy.b_blocknr = -1000;
1066        buffer_trace_init(&dummy.b_history);
1067        err = ext3_get_blocks_handle(handle, inode, block, 1,
1068                                        &dummy, create);
1069        /*
1070         * ext3_get_blocks_handle() returns number of blocks
1071         * mapped. 0 in case of a HOLE.
1072         */
1073        if (err > 0) {
1074                if (err > 1)
1075                        WARN_ON(1);
1076                err = 0;
1077        }
1078        *errp = err;
1079        if (!err && buffer_mapped(&dummy)) {
1080                struct buffer_head *bh;
1081                bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1082                if (!bh) {
1083                        *errp = -EIO;
1084                        goto err;
1085                }
1086                if (buffer_new(&dummy)) {
1087                        J_ASSERT(create != 0);
1088                        J_ASSERT(handle != NULL);
1089
1090                        /*
1091                         * Now that we do not always journal data, we should
1092                         * keep in mind whether this should always journal the
1093                         * new buffer as metadata.  For now, regular file
1094                         * writes use ext3_get_block instead, so it's not a
1095                         * problem.
1096                         */
1097                        lock_buffer(bh);
1098                        BUFFER_TRACE(bh, "call get_create_access");
1099                        fatal = ext3_journal_get_create_access(handle, bh);
1100                        if (!fatal && !buffer_uptodate(bh)) {
1101                                memset(bh->b_data,0,inode->i_sb->s_blocksize);
1102                                set_buffer_uptodate(bh);
1103                        }
1104                        unlock_buffer(bh);
1105                        BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
1106                        err = ext3_journal_dirty_metadata(handle, bh);
1107                        if (!fatal)
1108                                fatal = err;
1109                } else {
1110                        BUFFER_TRACE(bh, "not a new buffer");
1111                }
1112                if (fatal) {
1113                        *errp = fatal;
1114                        brelse(bh);
1115                        bh = NULL;
1116                }
1117                return bh;
1118        }
1119err:
1120        return NULL;
1121}
1122
1123struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
1124                               int block, int create, int *err)
1125{
1126        struct buffer_head * bh;
1127
1128        bh = ext3_getblk(handle, inode, block, create, err);
1129        if (!bh)
1130                return bh;
1131        if (bh_uptodate_or_lock(bh))
1132                return bh;
1133        get_bh(bh);
1134        bh->b_end_io = end_buffer_read_sync;
1135        submit_bh(READ | REQ_META | REQ_PRIO, bh);
1136        wait_on_buffer(bh);
1137        if (buffer_uptodate(bh))
1138                return bh;
1139        put_bh(bh);
1140        *err = -EIO;
1141        return NULL;
1142}
1143
1144static int walk_page_buffers(   handle_t *handle,
1145                                struct buffer_head *head,
1146                                unsigned from,
1147                                unsigned to,
1148                                int *partial,
1149                                int (*fn)(      handle_t *handle,
1150                                                struct buffer_head *bh))
1151{
1152        struct buffer_head *bh;
1153        unsigned block_start, block_end;
1154        unsigned blocksize = head->b_size;
1155        int err, ret = 0;
1156        struct buffer_head *next;
1157
1158        for (   bh = head, block_start = 0;
1159                ret == 0 && (bh != head || !block_start);
1160                block_start = block_end, bh = next)
1161        {
1162                next = bh->b_this_page;
1163                block_end = block_start + blocksize;
1164                if (block_end <= from || block_start >= to) {
1165                        if (partial && !buffer_uptodate(bh))
1166                                *partial = 1;
1167                        continue;
1168                }
1169                err = (*fn)(handle, bh);
1170                if (!ret)
1171                        ret = err;
1172        }
1173        return ret;
1174}
1175
1176/*
1177 * To preserve ordering, it is essential that the hole instantiation and
1178 * the data write be encapsulated in a single transaction.  We cannot
1179 * close off a transaction and start a new one between the ext3_get_block()
1180 * and the commit_write().  So doing the journal_start at the start of
1181 * prepare_write() is the right place.
1182 *
1183 * Also, this function can nest inside ext3_writepage() ->
1184 * block_write_full_page(). In that case, we *know* that ext3_writepage()
1185 * has generated enough buffer credits to do the whole page.  So we won't
1186 * block on the journal in that case, which is good, because the caller may
1187 * be PF_MEMALLOC.
1188 *
1189 * By accident, ext3 can be reentered when a transaction is open via
1190 * quota file writes.  If we were to commit the transaction while thus
1191 * reentered, there can be a deadlock - we would be holding a quota
1192 * lock, and the commit would never complete if another thread had a
1193 * transaction open and was blocking on the quota lock - a ranking
1194 * violation.
1195 *
1196 * So what we do is to rely on the fact that journal_stop/journal_start
1197 * will _not_ run commit under these circumstances because handle->h_ref
1198 * is elevated.  We'll still have enough credits for the tiny quotafile
1199 * write.
1200 */
1201static int do_journal_get_write_access(handle_t *handle,
1202                                        struct buffer_head *bh)
1203{
1204        int dirty = buffer_dirty(bh);
1205        int ret;
1206
1207        if (!buffer_mapped(bh) || buffer_freed(bh))
1208                return 0;
1209        /*
1210         * __block_prepare_write() could have dirtied some buffers. Clean
1211         * the dirty bit as jbd2_journal_get_write_access() could complain
1212         * otherwise about fs integrity issues. Setting of the dirty bit
1213         * by __block_prepare_write() isn't a real problem here as we clear
1214         * the bit before releasing a page lock and thus writeback cannot
1215         * ever write the buffer.
1216         */
1217        if (dirty)
1218                clear_buffer_dirty(bh);
1219        ret = ext3_journal_get_write_access(handle, bh);
1220        if (!ret && dirty)
1221                ret = ext3_journal_dirty_metadata(handle, bh);
1222        return ret;
1223}
1224
1225/*
1226 * Truncate blocks that were not used by write. We have to truncate the
1227 * pagecache as well so that corresponding buffers get properly unmapped.
1228 */
1229static void ext3_truncate_failed_write(struct inode *inode)
1230{
1231        truncate_inode_pages(inode->i_mapping, inode->i_size);
1232        ext3_truncate(inode);
1233}
1234
1235/*
1236 * Truncate blocks that were not used by direct IO write. We have to zero out
1237 * the last file block as well because direct IO might have written to it.
1238 */
1239static void ext3_truncate_failed_direct_write(struct inode *inode)
1240{
1241        ext3_block_truncate_page(inode, inode->i_size);
1242        ext3_truncate(inode);
1243}
1244
1245static int ext3_write_begin(struct file *file, struct address_space *mapping,
1246                                loff_t pos, unsigned len, unsigned flags,
1247                                struct page **pagep, void **fsdata)
1248{
1249        struct inode *inode = mapping->host;
1250        int ret;
1251        handle_t *handle;
1252        int retries = 0;
1253        struct page *page;
1254        pgoff_t index;
1255        unsigned from, to;
1256        /* Reserve one block more for addition to orphan list in case
1257         * we allocate blocks but write fails for some reason */
1258        int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;
1259
1260        trace_ext3_write_begin(inode, pos, len, flags);
1261
1262        index = pos >> PAGE_CACHE_SHIFT;
1263        from = pos & (PAGE_CACHE_SIZE - 1);
1264        to = from + len;
1265
1266retry:
1267        page = grab_cache_page_write_begin(mapping, index, flags);
1268        if (!page)
1269                return -ENOMEM;
1270        *pagep = page;
1271
1272        handle = ext3_journal_start(inode, needed_blocks);
1273        if (IS_ERR(handle)) {
1274                unlock_page(page);
1275                page_cache_release(page);
1276                ret = PTR_ERR(handle);
1277                goto out;
1278        }
1279        ret = __block_write_begin(page, pos, len, ext3_get_block);
1280        if (ret)
1281                goto write_begin_failed;
1282
1283        if (ext3_should_journal_data(inode)) {
1284                ret = walk_page_buffers(handle, page_buffers(page),
1285                                from, to, NULL, do_journal_get_write_access);
1286        }
1287write_begin_failed:
1288        if (ret) {
1289                /*
1290                 * block_write_begin may have instantiated a few blocks
1291                 * outside i_size.  Trim these off again. Don't need
1292                 * i_size_read because we hold i_mutex.
1293                 *
1294                 * Add inode to orphan list in case we crash before truncate
1295                 * finishes. Do this only if ext3_can_truncate() agrees so
1296                 * that orphan processing code is happy.
1297                 */
1298                if (pos + len > inode->i_size && ext3_can_truncate(inode))
1299                        ext3_orphan_add(handle, inode);
1300                ext3_journal_stop(handle);
1301                unlock_page(page);
1302                page_cache_release(page);
1303                if (pos + len > inode->i_size)
1304                        ext3_truncate_failed_write(inode);
1305        }
1306        if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1307                goto retry;
1308out:
1309        return ret;
1310}
1311
1312
1313int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1314{
1315        int err = journal_dirty_data(handle, bh);
1316        if (err)
1317                ext3_journal_abort_handle(__func__, __func__,
1318                                                bh, handle, err);
1319        return err;
1320}
1321
1322/* For ordered writepage and write_end functions */
1323static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1324{
1325        /*
1326         * Write could have mapped the buffer but it didn't copy the data in
1327         * yet. So avoid filing such buffer into a transaction.
1328         */
1329        if (buffer_mapped(bh) && buffer_uptodate(bh))
1330                return ext3_journal_dirty_data(handle, bh);
1331        return 0;
1332}
1333
1334/* For write_end() in data=journal mode */
1335static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1336{
1337        if (!buffer_mapped(bh) || buffer_freed(bh))
1338                return 0;
1339        set_buffer_uptodate(bh);
1340        return ext3_journal_dirty_metadata(handle, bh);
1341}
1342
1343/*
1344 * This is nasty and subtle: ext3_write_begin() could have allocated blocks
1345 * for the whole page but later we failed to copy the data in. Update inode
1346 * size according to what we managed to copy. The rest is going to be
1347 * truncated in write_end function.
1348 */
1349static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
1350{
1351        /* What matters to us is i_disksize. We don't write i_size anywhere */
1352        if (pos + copied > inode->i_size)
1353                i_size_write(inode, pos + copied);
1354        if (pos + copied > EXT3_I(inode)->i_disksize) {
1355                EXT3_I(inode)->i_disksize = pos + copied;
1356                mark_inode_dirty(inode);
1357        }
1358}
1359
1360/*
1361 * We need to pick up the new inode size which generic_commit_write gave us
1362 * `file' can be NULL - eg, when called from page_symlink().
1363 *
1364 * ext3 never places buffers on inode->i_mapping->private_list.  metadata
1365 * buffers are managed internally.
1366 */
1367static int ext3_ordered_write_end(struct file *file,
1368                                struct address_space *mapping,
1369                                loff_t pos, unsigned len, unsigned copied,
1370                                struct page *page, void *fsdata)
1371{
1372        handle_t *handle = ext3_journal_current_handle();
1373        struct inode *inode = file->f_mapping->host;
1374        unsigned from, to;
1375        int ret = 0, ret2;
1376
1377        trace_ext3_ordered_write_end(inode, pos, len, copied);
1378        copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1379
1380        from = pos & (PAGE_CACHE_SIZE - 1);
1381        to = from + copied;
1382        ret = walk_page_buffers(handle, page_buffers(page),
1383                from, to, NULL, journal_dirty_data_fn);
1384
1385        if (ret == 0)
1386                update_file_sizes(inode, pos, copied);
1387        /*
1388         * There may be allocated blocks outside of i_size because
1389         * we failed to copy some data. Prepare for truncate.
1390         */
1391        if (pos + len > inode->i_size && ext3_can_truncate(inode))
1392                ext3_orphan_add(handle, inode);
1393        ret2 = ext3_journal_stop(handle);
1394        if (!ret)
1395                ret = ret2;
1396        unlock_page(page);
1397        page_cache_release(page);
1398
1399        if (pos + len > inode->i_size)
1400                ext3_truncate_failed_write(inode);
1401        return ret ? ret : copied;
1402}
1403
1404static int ext3_writeback_write_end(struct file *file,
1405                                struct address_space *mapping,
1406                                loff_t pos, unsigned len, unsigned copied,
1407                                struct page *page, void *fsdata)
1408{
1409        handle_t *handle = ext3_journal_current_handle();
1410        struct inode *inode = file->f_mapping->host;
1411        int ret;
1412
1413        trace_ext3_writeback_write_end(inode, pos, len, copied);
1414        copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1415        update_file_sizes(inode, pos, copied);
1416        /*
1417         * There may be allocated blocks outside of i_size because
1418         * we failed to copy some data. Prepare for truncate.
1419         */
1420        if (pos + len > inode->i_size && ext3_can_truncate(inode))
1421                ext3_orphan_add(handle, inode);
1422        ret = ext3_journal_stop(handle);
1423        unlock_page(page);
1424        page_cache_release(page);
1425
1426        if (pos + len > inode->i_size)
1427                ext3_truncate_failed_write(inode);
1428        return ret ? ret : copied;
1429}
1430
1431static int ext3_journalled_write_end(struct file *file,
1432                                struct address_space *mapping,
1433                                loff_t pos, unsigned len, unsigned copied,
1434                                struct page *page, void *fsdata)
1435{
1436        handle_t *handle = ext3_journal_current_handle();
1437        struct inode *inode = mapping->host;
1438        struct ext3_inode_info *ei = EXT3_I(inode);
1439        int ret = 0, ret2;
1440        int partial = 0;
1441        unsigned from, to;
1442
1443        trace_ext3_journalled_write_end(inode, pos, len, copied);
1444        from = pos & (PAGE_CACHE_SIZE - 1);
1445        to = from + len;
1446
1447        if (copied < len) {
1448                if (!PageUptodate(page))
1449                        copied = 0;
1450                page_zero_new_buffers(page, from + copied, to);
1451                to = from + copied;
1452        }
1453
1454        ret = walk_page_buffers(handle, page_buffers(page), from,
1455                                to, &partial, write_end_fn);
1456        if (!partial)
1457                SetPageUptodate(page);
1458
1459        if (pos + copied > inode->i_size)
1460                i_size_write(inode, pos + copied);
1461        /*
1462         * There may be allocated blocks outside of i_size because
1463         * we failed to copy some data. Prepare for truncate.
1464         */
1465        if (pos + len > inode->i_size && ext3_can_truncate(inode))
1466                ext3_orphan_add(handle, inode);
1467        ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1468        atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
1469        if (inode->i_size > ei->i_disksize) {
1470                ei->i_disksize = inode->i_size;
1471                ret2 = ext3_mark_inode_dirty(handle, inode);
1472                if (!ret)
1473                        ret = ret2;
1474        }
1475
1476        ret2 = ext3_journal_stop(handle);
1477        if (!ret)
1478                ret = ret2;
1479        unlock_page(page);
1480        page_cache_release(page);
1481
1482        if (pos + len > inode->i_size)
1483                ext3_truncate_failed_write(inode);
1484        return ret ? ret : copied;
1485}
1486
1487/*
1488 * bmap() is special.  It gets used by applications such as lilo and by
1489 * the swapper to find the on-disk block of a specific piece of data.
1490 *
1491 * Naturally, this is dangerous if the block concerned is still in the
1492 * journal.  If somebody makes a swapfile on an ext3 data-journaling
1493 * filesystem and enables swap, then they may get a nasty shock when the
1494 * data getting swapped to that swapfile suddenly gets overwritten by
1495 * the original zero's written out previously to the journal and
1496 * awaiting writeback in the kernel's buffer cache.
1497 *
1498 * So, if we see any bmap calls here on a modified, data-journaled file,
1499 * take extra steps to flush any blocks which might be in the cache.
1500 */
1501static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
1502{
1503        struct inode *inode = mapping->host;
1504        journal_t *journal;
1505        int err;
1506
1507        if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
1508                /*
1509                 * This is a REALLY heavyweight approach, but the use of
1510                 * bmap on dirty files is expected to be extremely rare:
1511                 * only if we run lilo or swapon on a freshly made file
1512                 * do we expect this to happen.
1513                 *
1514                 * (bmap requires CAP_SYS_RAWIO so this does not
1515                 * represent an unprivileged user DOS attack --- we'd be
1516                 * in trouble if mortal users could trigger this path at
1517                 * will.)
1518                 *
1519                 * NB. EXT3_STATE_JDATA is not set on files other than
1520                 * regular files.  If somebody wants to bmap a directory
1521                 * or symlink and gets confused because the buffer
1522                 * hasn't yet been flushed to disk, they deserve
1523                 * everything they get.
1524                 */
1525
1526                ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
1527                journal = EXT3_JOURNAL(inode);
1528                journal_lock_updates(journal);
1529                err = journal_flush(journal);
1530                journal_unlock_updates(journal);
1531
1532                if (err)
1533                        return 0;
1534        }
1535
1536        return generic_block_bmap(mapping,block,ext3_get_block);
1537}
1538
1539static int bget_one(handle_t *handle, struct buffer_head *bh)
1540{
1541        get_bh(bh);
1542        return 0;
1543}
1544
1545static int bput_one(handle_t *handle, struct buffer_head *bh)
1546{
1547        put_bh(bh);
1548        return 0;
1549}
1550
1551static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
1552{
1553        return !buffer_mapped(bh);
1554}
1555
1556/*
1557 * Note that we always start a transaction even if we're not journalling
1558 * data.  This is to preserve ordering: any hole instantiation within
1559 * __block_write_full_page -> ext3_get_block() should be journalled
1560 * along with the data so we don't crash and then get metadata which
1561 * refers to old data.
1562 *
1563 * In all journalling modes block_write_full_page() will start the I/O.
1564 *
1565 * Problem:
1566 *
1567 *      ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1568 *              ext3_writepage()
1569 *
1570 * Similar for:
1571 *
1572 *      ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1573 *
1574 * Same applies to ext3_get_block().  We will deadlock on various things like
1575 * lock_journal and i_truncate_mutex.
1576 *
1577 * Setting PF_MEMALLOC here doesn't work - too many internal memory
1578 * allocations fail.
1579 *
1580 * 16May01: If we're reentered then journal_current_handle() will be
1581 *          non-zero. We simply *return*.
1582 *
1583 * 1 July 2001: @@@ FIXME:
1584 *   In journalled data mode, a data buffer may be metadata against the
1585 *   current transaction.  But the same file is part of a shared mapping
1586 *   and someone does a writepage() on it.
1587 *
1588 *   We will move the buffer onto the async_data list, but *after* it has
1589 *   been dirtied. So there's a small window where we have dirty data on
1590 *   BJ_Metadata.
1591 *
1592 *   Note that this only applies to the last partial page in the file.  The
1593 *   bit which block_write_full_page() uses prepare/commit for.  (That's
1594 *   broken code anyway: it's wrong for msync()).
1595 *
1596 *   It's a rare case: affects the final partial page, for journalled data
1597 *   where the file is subject to bith write() and writepage() in the same
1598 *   transction.  To fix it we'll need a custom block_write_full_page().
1599 *   We'll probably need that anyway for journalling writepage() output.
1600 *
1601 * We don't honour synchronous mounts for writepage().  That would be
1602 * disastrous.  Any write() or metadata operation will sync the fs for
1603 * us.
1604 *
1605 * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
1606 * we don't need to open a transaction here.
1607 */
1608static int ext3_ordered_writepage(struct page *page,
1609                                struct writeback_control *wbc)
1610{
1611        struct inode *inode = page->mapping->host;
1612        struct buffer_head *page_bufs;
1613        handle_t *handle = NULL;
1614        int ret = 0;
1615        int err;
1616
1617        J_ASSERT(PageLocked(page));
1618        /*
1619         * We don't want to warn for emergency remount. The condition is
1620         * ordered to avoid dereferencing inode->i_sb in non-error case to
1621         * avoid slow-downs.
1622         */
1623        WARN_ON_ONCE(IS_RDONLY(inode) &&
1624                     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1625
1626        /*
1627         * We give up here if we're reentered, because it might be for a
1628         * different filesystem.
1629         */
1630        if (ext3_journal_current_handle())
1631                goto out_fail;
1632
1633        trace_ext3_ordered_writepage(page);
1634        if (!page_has_buffers(page)) {
1635                create_empty_buffers(page, inode->i_sb->s_blocksize,
1636                                (1 << BH_Dirty)|(1 << BH_Uptodate));
1637                page_bufs = page_buffers(page);
1638        } else {
1639                page_bufs = page_buffers(page);
1640                if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
1641                                       NULL, buffer_unmapped)) {
1642                        /* Provide NULL get_block() to catch bugs if buffers
1643                         * weren't really mapped */
1644                        return block_write_full_page(page, NULL, wbc);
1645                }
1646        }
1647        handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1648
1649        if (IS_ERR(handle)) {
1650                ret = PTR_ERR(handle);
1651                goto out_fail;
1652        }
1653
1654        walk_page_buffers(handle, page_bufs, 0,
1655                        PAGE_CACHE_SIZE, NULL, bget_one);
1656
1657        ret = block_write_full_page(page, ext3_get_block, wbc);
1658
1659        /*
1660         * The page can become unlocked at any point now, and
1661         * truncate can then come in and change things.  So we
1662         * can't touch *page from now on.  But *page_bufs is
1663         * safe due to elevated refcount.
1664         */
1665
1666        /*
1667         * And attach them to the current transaction.  But only if
1668         * block_write_full_page() succeeded.  Otherwise they are unmapped,
1669         * and generally junk.
1670         */
1671        if (ret == 0) {
1672                err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1673                                        NULL, journal_dirty_data_fn);
1674                if (!ret)
1675                        ret = err;
1676        }
1677        walk_page_buffers(handle, page_bufs, 0,
1678                        PAGE_CACHE_SIZE, NULL, bput_one);
1679        err = ext3_journal_stop(handle);
1680        if (!ret)
1681                ret = err;
1682        return ret;
1683
1684out_fail:
1685        redirty_page_for_writepage(wbc, page);
1686        unlock_page(page);
1687        return ret;
1688}
1689
1690static int ext3_writeback_writepage(struct page *page,
1691                                struct writeback_control *wbc)
1692{
1693        struct inode *inode = page->mapping->host;
1694        handle_t *handle = NULL;
1695        int ret = 0;
1696        int err;
1697
1698        J_ASSERT(PageLocked(page));
1699        /*
1700         * We don't want to warn for emergency remount. The condition is
1701         * ordered to avoid dereferencing inode->i_sb in non-error case to
1702         * avoid slow-downs.
1703         */
1704        WARN_ON_ONCE(IS_RDONLY(inode) &&
1705                     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1706
1707        if (ext3_journal_current_handle())
1708                goto out_fail;
1709
1710        trace_ext3_writeback_writepage(page);
1711        if (page_has_buffers(page)) {
1712                if (!walk_page_buffers(NULL, page_buffers(page), 0,
1713                                      PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
1714                        /* Provide NULL get_block() to catch bugs if buffers
1715                         * weren't really mapped */
1716                        return block_write_full_page(page, NULL, wbc);
1717                }
1718        }
1719
1720        handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1721        if (IS_ERR(handle)) {
1722                ret = PTR_ERR(handle);
1723                goto out_fail;
1724        }
1725
1726        ret = block_write_full_page(page, ext3_get_block, wbc);
1727
1728        err = ext3_journal_stop(handle);
1729        if (!ret)
1730                ret = err;
1731        return ret;
1732
1733out_fail:
1734        redirty_page_for_writepage(wbc, page);
1735        unlock_page(page);
1736        return ret;
1737}
1738
1739static int ext3_journalled_writepage(struct page *page,
1740                                struct writeback_control *wbc)
1741{
1742        struct inode *inode = page->mapping->host;
1743        handle_t *handle = NULL;
1744        int ret = 0;
1745        int err;
1746
1747        J_ASSERT(PageLocked(page));
1748        /*
1749         * We don't want to warn for emergency remount. The condition is
1750         * ordered to avoid dereferencing inode->i_sb in non-error case to
1751         * avoid slow-downs.
1752         */
1753        WARN_ON_ONCE(IS_RDONLY(inode) &&
1754                     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1755
1756        if (ext3_journal_current_handle())
1757                goto no_write;
1758
1759        trace_ext3_journalled_writepage(page);
1760        handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1761        if (IS_ERR(handle)) {
1762                ret = PTR_ERR(handle);
1763                goto no_write;
1764        }
1765
1766        if (!page_has_buffers(page) || PageChecked(page)) {
1767                /*
1768                 * It's mmapped pagecache.  Add buffers and journal it.  There
1769                 * doesn't seem much point in redirtying the page here.
1770                 */
1771                ClearPageChecked(page);
1772                ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
1773                                          ext3_get_block);
1774                if (ret != 0) {
1775                        ext3_journal_stop(handle);
1776                        goto out_unlock;
1777                }
1778                ret = walk_page_buffers(handle, page_buffers(page), 0,
1779                        PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1780
1781                err = walk_page_buffers(handle, page_buffers(page), 0,
1782                                PAGE_CACHE_SIZE, NULL, write_end_fn);
1783                if (ret == 0)
1784                        ret = err;
1785                ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1786                atomic_set(&EXT3_I(inode)->i_datasync_tid,
1787                           handle->h_transaction->t_tid);
1788                unlock_page(page);
1789        } else {
1790                /*
1791                 * It may be a page full of checkpoint-mode buffers.  We don't
1792                 * really know unless we go poke around in the buffer_heads.
1793                 * But block_write_full_page will do the right thing.
1794                 */
1795                ret = block_write_full_page(page, ext3_get_block, wbc);
1796        }
1797        err = ext3_journal_stop(handle);
1798        if (!ret)
1799                ret = err;
1800out:
1801        return ret;
1802
1803no_write:
1804        redirty_page_for_writepage(wbc, page);
1805out_unlock:
1806        unlock_page(page);
1807        goto out;
1808}
1809
1810static int ext3_readpage(struct file *file, struct page *page)
1811{
1812        trace_ext3_readpage(page);
1813        return mpage_readpage(page, ext3_get_block);
1814}
1815
1816static int
1817ext3_readpages(struct file *file, struct address_space *mapping,
1818                struct list_head *pages, unsigned nr_pages)
1819{
1820        return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1821}
1822
1823static void ext3_invalidatepage(struct page *page, unsigned long offset)
1824{
1825        journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1826
1827        trace_ext3_invalidatepage(page, offset);
1828
1829        /*
1830         * If it's a full truncate we just forget about the pending dirtying
1831         */
1832        if (offset == 0)
1833                ClearPageChecked(page);
1834
1835        journal_invalidatepage(journal, page, offset);
1836}
1837
1838static int ext3_releasepage(struct page *page, gfp_t wait)
1839{
1840        journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1841
1842        trace_ext3_releasepage(page);
1843        WARN_ON(PageChecked(page));
1844        if (!page_has_buffers(page))
1845                return 0;
1846        return journal_try_to_free_buffers(journal, page, wait);
1847}
1848
1849/*
1850 * If the O_DIRECT write will extend the file then add this inode to the
1851 * orphan list.  So recovery will truncate it back to the original size
1852 * if the machine crashes during the write.
1853 *
1854 * If the O_DIRECT write is intantiating holes inside i_size and the machine
1855 * crashes then stale disk data _may_ be exposed inside the file. But current
1856 * VFS code falls back into buffered path in that case so we are safe.
1857 */
1858static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
1859                        const struct iovec *iov, loff_t offset,
1860                        unsigned long nr_segs)
1861{
1862        struct file *file = iocb->ki_filp;
1863        struct inode *inode = file->f_mapping->host;
1864        struct ext3_inode_info *ei = EXT3_I(inode);
1865        handle_t *handle;
1866        ssize_t ret;
1867        int orphan = 0;
1868        size_t count = iov_length(iov, nr_segs);
1869        int retries = 0;
1870
1871        trace_ext3_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
1872
1873        if (rw == WRITE) {
1874                loff_t final_size = offset + count;
1875
1876                if (final_size > inode->i_size) {
1877                        /* Credits for sb + inode write */
1878                        handle = ext3_journal_start(inode, 2);
1879                        if (IS_ERR(handle)) {
1880                                ret = PTR_ERR(handle);
1881                                goto out;
1882                        }
1883                        ret = ext3_orphan_add(handle, inode);
1884                        if (ret) {
1885                                ext3_journal_stop(handle);
1886                                goto out;
1887                        }
1888                        orphan = 1;
1889                        ei->i_disksize = inode->i_size;
1890                        ext3_journal_stop(handle);
1891                }
1892        }
1893
1894retry:
1895        ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
1896                                 ext3_get_block);
1897        /*
1898         * In case of error extending write may have instantiated a few
1899         * blocks outside i_size. Trim these off again.
1900         */
1901        if (unlikely((rw & WRITE) && ret < 0)) {
1902                loff_t isize = i_size_read(inode);
1903                loff_t end = offset + iov_length(iov, nr_segs);
1904
1905                if (end > isize)
1906                        ext3_truncate_failed_direct_write(inode);
1907        }
1908        if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1909                goto retry;
1910
1911        if (orphan) {
1912                int err;
1913
1914                /* Credits for sb + inode write */
1915                handle = ext3_journal_start(inode, 2);
1916                if (IS_ERR(handle)) {
1917                        /* This is really bad luck. We've written the data
1918                         * but cannot extend i_size. Truncate allocated blocks
1919                         * and pretend the write failed... */
1920                        ext3_truncate_failed_direct_write(inode);
1921                        ret = PTR_ERR(handle);
1922                        goto out;
1923                }
1924                if (inode->i_nlink)
1925                        ext3_orphan_del(handle, inode);
1926                if (ret > 0) {
1927                        loff_t end = offset + ret;
1928                        if (end > inode->i_size) {
1929                                ei->i_disksize = end;
1930                                i_size_write(inode, end);
1931                                /*
1932                                 * We're going to return a positive `ret'
1933                                 * here due to non-zero-length I/O, so there's
1934                                 * no way of reporting error returns from
1935                                 * ext3_mark_inode_dirty() to userspace.  So
1936                                 * ignore it.
1937                                 */
1938                                ext3_mark_inode_dirty(handle, inode);
1939                        }
1940                }
1941                err = ext3_journal_stop(handle);
1942                if (ret == 0)
1943                        ret = err;
1944        }
1945out:
1946        trace_ext3_direct_IO_exit(inode, offset,
1947                                iov_length(iov, nr_segs), rw, ret);
1948        return ret;
1949}
1950
1951/*
1952 * Pages can be marked dirty completely asynchronously from ext3's journalling
1953 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
1954 * much here because ->set_page_dirty is called under VFS locks.  The page is
1955 * not necessarily locked.
1956 *
1957 * We cannot just dirty the page and leave attached buffers clean, because the
1958 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
1959 * or jbddirty because all the journalling code will explode.
1960 *
1961 * So what we do is to mark the page "pending dirty" and next time writepage
1962 * is called, propagate that into the buffers appropriately.
1963 */
1964static int ext3_journalled_set_page_dirty(struct page *page)
1965{
1966        SetPageChecked(page);
1967        return __set_page_dirty_nobuffers(page);
1968}
1969
1970static const struct address_space_operations ext3_ordered_aops = {
1971        .readpage               = ext3_readpage,
1972        .readpages              = ext3_readpages,
1973        .writepage              = ext3_ordered_writepage,
1974        .write_begin            = ext3_write_begin,
1975        .write_end              = ext3_ordered_write_end,
1976        .bmap                   = ext3_bmap,
1977        .invalidatepage         = ext3_invalidatepage,
1978        .releasepage            = ext3_releasepage,
1979        .direct_IO              = ext3_direct_IO,
1980        .migratepage            = buffer_migrate_page,
1981        .is_partially_uptodate  = block_is_partially_uptodate,
1982        .error_remove_page      = generic_error_remove_page,
1983};
1984
1985static const struct address_space_operations ext3_writeback_aops = {
1986        .readpage               = ext3_readpage,
1987        .readpages              = ext3_readpages,
1988        .writepage              = ext3_writeback_writepage,
1989        .write_begin            = ext3_write_begin,
1990        .write_end              = ext3_writeback_write_end,
1991        .bmap                   = ext3_bmap,
1992        .invalidatepage         = ext3_invalidatepage,
1993        .releasepage            = ext3_releasepage,
1994        .direct_IO              = ext3_direct_IO,
1995        .migratepage            = buffer_migrate_page,
1996        .is_partially_uptodate  = block_is_partially_uptodate,
1997        .error_remove_page      = generic_error_remove_page,
1998};
1999
2000static const struct address_space_operations ext3_journalled_aops = {
2001        .readpage               = ext3_readpage,
2002        .readpages              = ext3_readpages,
2003        .writepage              = ext3_journalled_writepage,
2004        .write_begin            = ext3_write_begin,
2005        .write_end              = ext3_journalled_write_end,
2006        .set_page_dirty         = ext3_journalled_set_page_dirty,
2007        .bmap                   = ext3_bmap,
2008        .invalidatepage         = ext3_invalidatepage,
2009        .releasepage            = ext3_releasepage,
2010        .is_partially_uptodate  = block_is_partially_uptodate,
2011        .error_remove_page      = generic_error_remove_page,
2012};
2013
2014void ext3_set_aops(struct inode *inode)
2015{
2016        if (ext3_should_order_data(inode))
2017                inode->i_mapping->a_ops = &ext3_ordered_aops;
2018        else if (ext3_should_writeback_data(inode))
2019                inode->i_mapping->a_ops = &ext3_writeback_aops;
2020        else
2021                inode->i_mapping->a_ops = &ext3_journalled_aops;
2022}
2023
2024/*
2025 * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
2026 * up to the end of the block which corresponds to `from'.
2027 * This required during truncate. We need to physically zero the tail end
2028 * of that block so it doesn't yield old data if the file is later grown.
2029 */
2030static int ext3_block_truncate_page(struct inode *inode, loff_t from)
2031{
2032        ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
2033        unsigned offset = from & (PAGE_CACHE_SIZE - 1);
2034        unsigned blocksize, iblock, length, pos;
2035        struct page *page;
2036        handle_t *handle = NULL;
2037        struct buffer_head *bh;
2038        int err = 0;
2039
2040        /* Truncated on block boundary - nothing to do */
2041        blocksize = inode->i_sb->s_blocksize;
2042        if ((from & (blocksize - 1)) == 0)
2043                return 0;
2044
2045        page = grab_cache_page(inode->i_mapping, index);
2046        if (!page)
2047                return -ENOMEM;
2048        length = blocksize - (offset & (blocksize - 1));
2049        iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2050
2051        if (!page_has_buffers(page))
2052                create_empty_buffers(page, blocksize, 0);
2053
2054        /* Find the buffer that contains "offset" */
2055        bh = page_buffers(page);
2056        pos = blocksize;
2057        while (offset >= pos) {
2058                bh = bh->b_this_page;
2059                iblock++;
2060                pos += blocksize;
2061        }
2062
2063        err = 0;
2064        if (buffer_freed(bh)) {
2065                BUFFER_TRACE(bh, "freed: skip");
2066                goto unlock;
2067        }
2068
2069        if (!buffer_mapped(bh)) {
2070                BUFFER_TRACE(bh, "unmapped");
2071                ext3_get_block(inode, iblock, bh, 0);
2072                /* unmapped? It's a hole - nothing to do */
2073                if (!buffer_mapped(bh)) {
2074                        BUFFER_TRACE(bh, "still unmapped");
2075                        goto unlock;
2076                }
2077        }
2078
2079        /* Ok, it's mapped. Make sure it's up-to-date */
2080        if (PageUptodate(page))
2081                set_buffer_uptodate(bh);
2082
2083        if (!bh_uptodate_or_lock(bh)) {
2084                err = bh_submit_read(bh);
2085                /* Uhhuh. Read error. Complain and punt. */
2086                if (err)
2087                        goto unlock;
2088        }
2089
2090        /* data=writeback mode doesn't need transaction to zero-out data */
2091        if (!ext3_should_writeback_data(inode)) {
2092                /* We journal at most one block */
2093                handle = ext3_journal_start(inode, 1);
2094                if (IS_ERR(handle)) {
2095                        clear_highpage(page);
2096                        flush_dcache_page(page);
2097                        err = PTR_ERR(handle);
2098                        goto unlock;
2099                }
2100        }
2101
2102        if (ext3_should_journal_data(inode)) {
2103                BUFFER_TRACE(bh, "get write access");
2104                err = ext3_journal_get_write_access(handle, bh);
2105                if (err)
2106                        goto stop;
2107        }
2108
2109        zero_user(page, offset, length);
2110        BUFFER_TRACE(bh, "zeroed end of block");
2111
2112        err = 0;
2113        if (ext3_should_journal_data(inode)) {
2114                err = ext3_journal_dirty_metadata(handle, bh);
2115        } else {
2116                if (ext3_should_order_data(inode))
2117                        err = ext3_journal_dirty_data(handle, bh);
2118                mark_buffer_dirty(bh);
2119        }
2120stop:
2121        if (handle)
2122                ext3_journal_stop(handle);
2123
2124unlock:
2125        unlock_page(page);
2126        page_cache_release(page);
2127        return err;
2128}
2129
2130/*
2131 * Probably it should be a library function... search for first non-zero word
2132 * or memcmp with zero_page, whatever is better for particular architecture.
2133 * Linus?
2134 */
2135static inline int all_zeroes(__le32 *p, __le32 *q)
2136{
2137        while (p < q)
2138                if (*p++)
2139                        return 0;
2140        return 1;
2141}
2142
2143/**
2144 *      ext3_find_shared - find the indirect blocks for partial truncation.
2145 *      @inode:   inode in question
2146 *      @depth:   depth of the affected branch
2147 *      @offsets: offsets of pointers in that branch (see ext3_block_to_path)
2148 *      @chain:   place to store the pointers to partial indirect blocks
2149 *      @top:     place to the (detached) top of branch
2150 *
2151 *      This is a helper function used by ext3_truncate().
2152 *
2153 *      When we do truncate() we may have to clean the ends of several
2154 *      indirect blocks but leave the blocks themselves alive. Block is
2155 *      partially truncated if some data below the new i_size is referred
2156 *      from it (and it is on the path to the first completely truncated
2157 *      data block, indeed).  We have to free the top of that path along
2158 *      with everything to the right of the path. Since no allocation
2159 *      past the truncation point is possible until ext3_truncate()
2160 *      finishes, we may safely do the latter, but top of branch may
2161 *      require special attention - pageout below the truncation point
2162 *      might try to populate it.
2163 *
2164 *      We atomically detach the top of branch from the tree, store the
2165 *      block number of its root in *@top, pointers to buffer_heads of
2166 *      partially truncated blocks - in @chain[].bh and pointers to
2167 *      their last elements that should not be removed - in
2168 *      @chain[].p. Return value is the pointer to last filled element
2169 *      of @chain.
2170 *
2171 *      The work left to caller to do the actual freeing of subtrees:
2172 *              a) free the subtree starting from *@top
2173 *              b) free the subtrees whose roots are stored in
2174 *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
2175 *              c) free the subtrees growing from the inode past the @chain[0].
2176 *                      (no partially truncated stuff there).  */
2177
2178static Indirect *ext3_find_shared(struct inode *inode, int depth,
2179                        int offsets[4], Indirect chain[4], __le32 *top)
2180{
2181        Indirect *partial, *p;
2182        int k, err;
2183
2184        *top = 0;
2185        /* Make k index the deepest non-null offset + 1 */
2186        for (k = depth; k > 1 && !offsets[k-1]; k--)
2187                ;
2188        partial = ext3_get_branch(inode, k, offsets, chain, &err);
2189        /* Writer: pointers */
2190        if (!partial)
2191                partial = chain + k-1;
2192        /*
2193         * If the branch acquired continuation since we've looked at it -
2194         * fine, it should all survive and (new) top doesn't belong to us.
2195         */
2196        if (!partial->key && *partial->p)
2197                /* Writer: end */
2198                goto no_top;
2199        for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
2200                ;
2201        /*
2202         * OK, we've found the last block that must survive. The rest of our
2203         * branch should be detached before unlocking. However, if that rest
2204         * of branch is all ours and does not grow immediately from the inode
2205         * it's easier to cheat and just decrement partial->p.
2206         */
2207        if (p == chain + k - 1 && p > chain) {
2208                p->p--;
2209        } else {
2210                *top = *p->p;
2211                /* Nope, don't do this in ext3.  Must leave the tree intact */
2212#if 0
2213                *p->p = 0;
2214#endif
2215        }
2216        /* Writer: end */
2217
2218        while(partial > p) {
2219                brelse(partial->bh);
2220                partial--;
2221        }
2222no_top:
2223        return partial;
2224}
2225
2226/*
2227 * Zero a number of block pointers in either an inode or an indirect block.
2228 * If we restart the transaction we must again get write access to the
2229 * indirect block for further modification.
2230 *
2231 * We release `count' blocks on disk, but (last - first) may be greater
2232 * than `count' because there can be holes in there.
2233 */
2234static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2235                struct buffer_head *bh, ext3_fsblk_t block_to_free,
2236                unsigned long count, __le32 *first, __le32 *last)
2237{
2238        __le32 *p;
2239        if (try_to_extend_transaction(handle, inode)) {
2240                if (bh) {
2241                        BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2242                        if (ext3_journal_dirty_metadata(handle, bh))
2243                                return;
2244                }
2245                ext3_mark_inode_dirty(handle, inode);
2246                truncate_restart_transaction(handle, inode);
2247                if (bh) {
2248                        BUFFER_TRACE(bh, "retaking write access");
2249                        if (ext3_journal_get_write_access(handle, bh))
2250                                return;
2251                }
2252        }
2253
2254        /*
2255         * Any buffers which are on the journal will be in memory. We find
2256         * them on the hash table so journal_revoke() will run journal_forget()
2257         * on them.  We've already detached each block from the file, so
2258         * bforget() in journal_forget() should be safe.
2259         *
2260         * AKPM: turn on bforget in journal_forget()!!!
2261         */
2262        for (p = first; p < last; p++) {
2263                u32 nr = le32_to_cpu(*p);
2264                if (nr) {
2265                        struct buffer_head *bh;
2266
2267                        *p = 0;
2268                        bh = sb_find_get_block(inode->i_sb, nr);
2269                        ext3_forget(handle, 0, inode, bh, nr);
2270                }
2271        }
2272
2273        ext3_free_blocks(handle, inode, block_to_free, count);
2274}
2275
2276/**
2277 * ext3_free_data - free a list of data blocks
2278 * @handle:     handle for this transaction
2279 * @inode:      inode we are dealing with
2280 * @this_bh:    indirect buffer_head which contains *@first and *@last
2281 * @first:      array of block numbers
2282 * @last:       points immediately past the end of array
2283 *
2284 * We are freeing all blocks referred from that array (numbers are stored as
2285 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2286 *
2287 * We accumulate contiguous runs of blocks to free.  Conveniently, if these
2288 * blocks are contiguous then releasing them at one time will only affect one
2289 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2290 * actually use a lot of journal space.
2291 *
2292 * @this_bh will be %NULL if @first and @last point into the inode's direct
2293 * block pointers.
2294 */
2295static void ext3_free_data(handle_t *handle, struct inode *inode,
2296                           struct buffer_head *this_bh,
2297                           __le32 *first, __le32 *last)
2298{
2299        ext3_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2300        unsigned long count = 0;            /* Number of blocks in the run */
2301        __le32 *block_to_free_p = NULL;     /* Pointer into inode/ind
2302                                               corresponding to
2303                                               block_to_free */
2304        ext3_fsblk_t nr;                    /* Current block # */
2305        __le32 *p;                          /* Pointer into inode/ind
2306                                               for current block */
2307        int err;
2308
2309        if (this_bh) {                          /* For indirect block */
2310                BUFFER_TRACE(this_bh, "get_write_access");
2311                err = ext3_journal_get_write_access(handle, this_bh);
2312                /* Important: if we can't update the indirect pointers
2313                 * to the blocks, we can't free them. */
2314                if (err)
2315                        return;
2316        }
2317
2318        for (p = first; p < last; p++) {
2319                nr = le32_to_cpu(*p);
2320                if (nr) {
2321                        /* accumulate blocks to free if they're contiguous */
2322                        if (count == 0) {
2323                                block_to_free = nr;
2324                                block_to_free_p = p;
2325                                count = 1;
2326                        } else if (nr == block_to_free + count) {
2327                                count++;
2328                        } else {
2329                                ext3_clear_blocks(handle, inode, this_bh,
2330                                                  block_to_free,
2331                                                  count, block_to_free_p, p);
2332                                block_to_free = nr;
2333                                block_to_free_p = p;
2334                                count = 1;
2335                        }
2336                }
2337        }
2338
2339        if (count > 0)
2340                ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2341                                  count, block_to_free_p, p);
2342
2343        if (this_bh) {
2344                BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2345
2346                /*
2347                 * The buffer head should have an attached journal head at this
2348                 * point. However, if the data is corrupted and an indirect
2349                 * block pointed to itself, it would have been detached when
2350                 * the block was cleared. Check for this instead of OOPSing.
2351                 */
2352                if (bh2jh(this_bh))
2353                        ext3_journal_dirty_metadata(handle, this_bh);
2354                else
2355                        ext3_error(inode->i_sb, "ext3_free_data",
2356                                   "circular indirect block detected, "
2357                                   "inode=%lu, block=%llu",
2358                                   inode->i_ino,
2359                                   (unsigned long long)this_bh->b_blocknr);
2360        }
2361}
2362
2363/**
2364 *      ext3_free_branches - free an array of branches
2365 *      @handle: JBD handle for this transaction
2366 *      @inode: inode we are dealing with
2367 *      @parent_bh: the buffer_head which contains *@first and *@last
2368 *      @first: array of block numbers
2369 *      @last:  pointer immediately past the end of array
2370 *      @depth: depth of the branches to free
2371 *
2372 *      We are freeing all blocks referred from these branches (numbers are
2373 *      stored as little-endian 32-bit) and updating @inode->i_blocks
2374 *      appropriately.
2375 */
2376static void ext3_free_branches(handle_t *handle, struct inode *inode,
2377                               struct buffer_head *parent_bh,
2378                               __le32 *first, __le32 *last, int depth)
2379{
2380        ext3_fsblk_t nr;
2381        __le32 *p;
2382
2383        if (is_handle_aborted(handle))
2384                return;
2385
2386        if (depth--) {
2387                struct buffer_head *bh;
2388                int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2389                p = last;
2390                while (--p >= first) {
2391                        nr = le32_to_cpu(*p);
2392                        if (!nr)
2393                                continue;               /* A hole */
2394
2395                        /* Go read the buffer for the next level down */
2396                        bh = sb_bread(inode->i_sb, nr);
2397
2398                        /*
2399                         * A read failure? Report error and clear slot
2400                         * (should be rare).
2401                         */
2402                        if (!bh) {
2403                                ext3_error(inode->i_sb, "ext3_free_branches",
2404                                           "Read failure, inode=%lu, block="E3FSBLK,
2405                                           inode->i_ino, nr);
2406                                continue;
2407                        }
2408
2409                        /* This zaps the entire block.  Bottom up. */
2410                        BUFFER_TRACE(bh, "free child branches");
2411                        ext3_free_branches(handle, inode, bh,
2412                                           (__le32*)bh->b_data,
2413                                           (__le32*)bh->b_data + addr_per_block,
2414                                           depth);
2415
2416                        /*
2417                         * Everything below this this pointer has been
2418                         * released.  Now let this top-of-subtree go.
2419                         *
2420                         * We want the freeing of this indirect block to be
2421                         * atomic in the journal with the updating of the
2422                         * bitmap block which owns it.  So make some room in
2423                         * the journal.
2424                         *
2425                         * We zero the parent pointer *after* freeing its
2426                         * pointee in the bitmaps, so if extend_transaction()
2427                         * for some reason fails to put the bitmap changes and
2428                         * the release into the same transaction, recovery
2429                         * will merely complain about releasing a free block,
2430                         * rather than leaking blocks.
2431                         */
2432                        if (is_handle_aborted(handle))
2433                                return;
2434                        if (try_to_extend_transaction(handle, inode)) {
2435                                ext3_mark_inode_dirty(handle, inode);
2436                                truncate_restart_transaction(handle, inode);
2437                        }
2438
2439                        /*
2440                         * We've probably journalled the indirect block several
2441                         * times during the truncate.  But it's no longer
2442                         * needed and we now drop it from the transaction via
2443                         * journal_revoke().
2444                         *
2445                         * That's easy if it's exclusively part of this
2446                         * transaction.  But if it's part of the committing
2447                         * transaction then journal_forget() will simply
2448                         * brelse() it.  That means that if the underlying
2449                         * block is reallocated in ext3_get_block(),
2450                         * unmap_underlying_metadata() will find this block
2451                         * and will try to get rid of it.  damn, damn. Thus
2452                         * we don't allow a block to be reallocated until
2453                         * a transaction freeing it has fully committed.
2454                         *
2455                         * We also have to make sure journal replay after a
2456                         * crash does not overwrite non-journaled data blocks
2457                         * with old metadata when the block got reallocated for
2458                         * data.  Thus we have to store a revoke record for a
2459                         * block in the same transaction in which we free the
2460                         * block.
2461                         */
2462                        ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2463
2464                        ext3_free_blocks(handle, inode, nr, 1);
2465
2466                        if (parent_bh) {
2467                                /*
2468                                 * The block which we have just freed is
2469                                 * pointed to by an indirect block: journal it
2470                                 */
2471                                BUFFER_TRACE(parent_bh, "get_write_access");
2472                                if (!ext3_journal_get_write_access(handle,
2473                                                                   parent_bh)){
2474                                        *p = 0;
2475                                        BUFFER_TRACE(parent_bh,
2476                                        "call ext3_journal_dirty_metadata");
2477                                        ext3_journal_dirty_metadata(handle,
2478                                                                    parent_bh);
2479                                }
2480                        }
2481                }
2482        } else {
2483                /* We have reached the bottom of the tree. */
2484                BUFFER_TRACE(parent_bh, "free data blocks");
2485                ext3_free_data(handle, inode, parent_bh, first, last);
2486        }
2487}
2488
2489int ext3_can_truncate(struct inode *inode)
2490{
2491        if (S_ISREG(inode->i_mode))
2492                return 1;
2493        if (S_ISDIR(inode->i_mode))
2494                return 1;
2495        if (S_ISLNK(inode->i_mode))
2496                return !ext3_inode_is_fast_symlink(inode);
2497        return 0;
2498}
2499
2500/*
2501 * ext3_truncate()
2502 *
2503 * We block out ext3_get_block() block instantiations across the entire
2504 * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2505 * simultaneously on behalf of the same inode.
2506 *
2507 * As we work through the truncate and commit bits of it to the journal there
2508 * is one core, guiding principle: the file's tree must always be consistent on
2509 * disk.  We must be able to restart the truncate after a crash.
2510 *
2511 * The file's tree may be transiently inconsistent in memory (although it
2512 * probably isn't), but whenever we close off and commit a journal transaction,
2513 * the contents of (the filesystem + the journal) must be consistent and
2514 * restartable.  It's pretty simple, really: bottom up, right to left (although
2515 * left-to-right works OK too).
2516 *
2517 * Note that at recovery time, journal replay occurs *before* the restart of
2518 * truncate against the orphan inode list.
2519 *
2520 * The committed inode has the new, desired i_size (which is the same as
2521 * i_disksize in this case).  After a crash, ext3_orphan_cleanup() will see
2522 * that this inode's truncate did not complete and it will again call
2523 * ext3_truncate() to have another go.  So there will be instantiated blocks
2524 * to the right of the truncation point in a crashed ext3 filesystem.  But
2525 * that's fine - as long as they are linked from the inode, the post-crash
2526 * ext3_truncate() run will find them and release them.
2527 */
2528void ext3_truncate(struct inode *inode)
2529{
2530        handle_t *handle;
2531        struct ext3_inode_info *ei = EXT3_I(inode);
2532        __le32 *i_data = ei->i_data;
2533        int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2534        int offsets[4];
2535        Indirect chain[4];
2536        Indirect *partial;
2537        __le32 nr = 0;
2538        int n;
2539        long last_block;
2540        unsigned blocksize = inode->i_sb->s_blocksize;
2541
2542        trace_ext3_truncate_enter(inode);
2543
2544        if (!ext3_can_truncate(inode))
2545                goto out_notrans;
2546
2547        if (inode->i_size == 0 && ext3_should_writeback_data(inode))
2548                ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
2549
2550        handle = start_transaction(inode);
2551        if (IS_ERR(handle))
2552                goto out_notrans;
2553
2554        last_block = (inode->i_size + blocksize-1)
2555                                        >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2556        n = ext3_block_to_path(inode, last_block, offsets, NULL);
2557        if (n == 0)
2558                goto out_stop;  /* error */
2559
2560        /*
2561         * OK.  This truncate is going to happen.  We add the inode to the
2562         * orphan list, so that if this truncate spans multiple transactions,
2563         * and we crash, we will resume the truncate when the filesystem
2564         * recovers.  It also marks the inode dirty, to catch the new size.
2565         *
2566         * Implication: the file must always be in a sane, consistent
2567         * truncatable state while each transaction commits.
2568         */
2569        if (ext3_orphan_add(handle, inode))
2570                goto out_stop;
2571
2572        /*
2573         * The orphan list entry will now protect us from any crash which
2574         * occurs before the truncate completes, so it is now safe to propagate
2575         * the new, shorter inode size (held for now in i_size) into the
2576         * on-disk inode. We do this via i_disksize, which is the value which
2577         * ext3 *really* writes onto the disk inode.
2578         */
2579        ei->i_disksize = inode->i_size;
2580
2581        /*
2582         * From here we block out all ext3_get_block() callers who want to
2583         * modify the block allocation tree.
2584         */
2585        mutex_lock(&ei->truncate_mutex);
2586
2587        if (n == 1) {           /* direct blocks */
2588                ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2589                               i_data + EXT3_NDIR_BLOCKS);
2590                goto do_indirects;
2591        }
2592
2593        partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2594        /* Kill the top of shared branch (not detached) */
2595        if (nr) {
2596                if (partial == chain) {
2597                        /* Shared branch grows from the inode */
2598                        ext3_free_branches(handle, inode, NULL,
2599                                           &nr, &nr+1, (chain+n-1) - partial);
2600                        *partial->p = 0;
2601                        /*
2602                         * We mark the inode dirty prior to restart,
2603                         * and prior to stop.  No need for it here.
2604                         */
2605                } else {
2606                        /* Shared branch grows from an indirect block */
2607                        ext3_free_branches(handle, inode, partial->bh,
2608                                        partial->p,
2609                                        partial->p+1, (chain+n-1) - partial);
2610                }
2611        }
2612        /* Clear the ends of indirect blocks on the shared branch */
2613        while (partial > chain) {
2614                ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2615                                   (__le32*)partial->bh->b_data+addr_per_block,
2616                                   (chain+n-1) - partial);
2617                BUFFER_TRACE(partial->bh, "call brelse");
2618                brelse (partial->bh);
2619                partial--;
2620        }
2621do_indirects:
2622        /* Kill the remaining (whole) subtrees */
2623        switch (offsets[0]) {
2624        default:
2625                nr = i_data[EXT3_IND_BLOCK];
2626                if (nr) {
2627                        ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2628                        i_data[EXT3_IND_BLOCK] = 0;
2629                }
2630        case EXT3_IND_BLOCK:
2631                nr = i_data[EXT3_DIND_BLOCK];
2632                if (nr) {
2633                        ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2634                        i_data[EXT3_DIND_BLOCK] = 0;
2635                }
2636        case EXT3_DIND_BLOCK:
2637                nr = i_data[EXT3_TIND_BLOCK];
2638                if (nr) {
2639                        ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2640                        i_data[EXT3_TIND_BLOCK] = 0;
2641                }
2642        case EXT3_TIND_BLOCK:
2643                ;
2644        }
2645
2646        ext3_discard_reservation(inode);
2647
2648        mutex_unlock(&ei->truncate_mutex);
2649        inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2650        ext3_mark_inode_dirty(handle, inode);
2651
2652        /*
2653         * In a multi-transaction truncate, we only make the final transaction
2654         * synchronous
2655         */
2656        if (IS_SYNC(inode))
2657                handle->h_sync = 1;
2658out_stop:
2659        /*
2660         * If this was a simple ftruncate(), and the file will remain alive
2661         * then we need to clear up the orphan record which we created above.
2662         * However, if this was a real unlink then we were called by
2663         * ext3_evict_inode(), and we allow that function to clean up the
2664         * orphan info for us.
2665         */
2666        if (inode->i_nlink)
2667                ext3_orphan_del(handle, inode);
2668
2669        ext3_journal_stop(handle);
2670        trace_ext3_truncate_exit(inode);
2671        return;
2672out_notrans:
2673        /*
2674         * Delete the inode from orphan list so that it doesn't stay there
2675         * forever and trigger assertion on umount.
2676         */
2677        if (inode->i_nlink)
2678                ext3_orphan_del(NULL, inode);
2679        trace_ext3_truncate_exit(inode);
2680}
2681
2682static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2683                unsigned long ino, struct ext3_iloc *iloc)
2684{
2685        unsigned long block_group;
2686        unsigned long offset;
2687        ext3_fsblk_t block;
2688        struct ext3_group_desc *gdp;
2689
2690        if (!ext3_valid_inum(sb, ino)) {
2691                /*
2692                 * This error is already checked for in namei.c unless we are
2693                 * looking at an NFS filehandle, in which case no error
2694                 * report is needed
2695                 */
2696                return 0;
2697        }
2698
2699        block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2700        gdp = ext3_get_group_desc(sb, block_group, NULL);
2701        if (!gdp)
2702                return 0;
2703        /*
2704         * Figure out the offset within the block group inode table
2705         */
2706        offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2707                EXT3_INODE_SIZE(sb);
2708        block = le32_to_cpu(gdp->bg_inode_table) +
2709                (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2710
2711        iloc->block_group = block_group;
2712        iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2713        return block;
2714}
2715
2716/*
2717 * ext3_get_inode_loc returns with an extra refcount against the inode's
2718 * underlying buffer_head on success. If 'in_mem' is true, we have all
2719 * data in memory that is needed to recreate the on-disk version of this
2720 * inode.
2721 */
2722static int __ext3_get_inode_loc(struct inode *inode,
2723                                struct ext3_iloc *iloc, int in_mem)
2724{
2725        ext3_fsblk_t block;
2726        struct buffer_head *bh;
2727
2728        block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2729        if (!block)
2730                return -EIO;
2731
2732        bh = sb_getblk(inode->i_sb, block);
2733        if (!bh) {
2734                ext3_error (inode->i_sb, "ext3_get_inode_loc",
2735                                "unable to read inode block - "
2736                                "inode=%lu, block="E3FSBLK,
2737                                 inode->i_ino, block);
2738                return -EIO;
2739        }
2740        if (!buffer_uptodate(bh)) {
2741                lock_buffer(bh);
2742
2743                /*
2744                 * If the buffer has the write error flag, we have failed
2745                 * to write out another inode in the same block.  In this
2746                 * case, we don't have to read the block because we may
2747                 * read the old inode data successfully.
2748                 */
2749                if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2750                        set_buffer_uptodate(bh);
2751
2752                if (buffer_uptodate(bh)) {
2753                        /* someone brought it uptodate while we waited */
2754                        unlock_buffer(bh);
2755                        goto has_buffer;
2756                }
2757
2758                /*
2759                 * If we have all information of the inode in memory and this
2760                 * is the only valid inode in the block, we need not read the
2761                 * block.
2762                 */
2763                if (in_mem) {
2764                        struct buffer_head *bitmap_bh;
2765                        struct ext3_group_desc *desc;
2766                        int inodes_per_buffer;
2767                        int inode_offset, i;
2768                        int block_group;
2769                        int start;
2770
2771                        block_group = (inode->i_ino - 1) /
2772                                        EXT3_INODES_PER_GROUP(inode->i_sb);
2773                        inodes_per_buffer = bh->b_size /
2774                                EXT3_INODE_SIZE(inode->i_sb);
2775                        inode_offset = ((inode->i_ino - 1) %
2776                                        EXT3_INODES_PER_GROUP(inode->i_sb));
2777                        start = inode_offset & ~(inodes_per_buffer - 1);
2778
2779                        /* Is the inode bitmap in cache? */
2780                        desc = ext3_get_group_desc(inode->i_sb,
2781                                                block_group, NULL);
2782                        if (!desc)
2783                                goto make_io;
2784
2785                        bitmap_bh = sb_getblk(inode->i_sb,
2786                                        le32_to_cpu(desc->bg_inode_bitmap));
2787                        if (!bitmap_bh)
2788                                goto make_io;
2789
2790                        /*
2791                         * If the inode bitmap isn't in cache then the
2792                         * optimisation may end up performing two reads instead
2793                         * of one, so skip it.
2794                         */
2795                        if (!buffer_uptodate(bitmap_bh)) {
2796                                brelse(bitmap_bh);
2797                                goto make_io;
2798                        }
2799                        for (i = start; i < start + inodes_per_buffer; i++) {
2800                                if (i == inode_offset)
2801                                        continue;
2802                                if (ext3_test_bit(i, bitmap_bh->b_data))
2803                                        break;
2804                        }
2805                        brelse(bitmap_bh);
2806                        if (i == start + inodes_per_buffer) {
2807                                /* all other inodes are free, so skip I/O */
2808                                memset(bh->b_data, 0, bh->b_size);
2809                                set_buffer_uptodate(bh);
2810                                unlock_buffer(bh);
2811                                goto has_buffer;
2812                        }
2813                }
2814
2815make_io:
2816                /*
2817                 * There are other valid inodes in the buffer, this inode
2818                 * has in-inode xattrs, or we don't have this inode in memory.
2819                 * Read the block from disk.
2820                 */
2821                trace_ext3_load_inode(inode);
2822                get_bh(bh);
2823                bh->b_end_io = end_buffer_read_sync;
2824                submit_bh(READ | REQ_META | REQ_PRIO, bh);
2825                wait_on_buffer(bh);
2826                if (!buffer_uptodate(bh)) {
2827                        ext3_error(inode->i_sb, "ext3_get_inode_loc",
2828                                        "unable to read inode block - "
2829                                        "inode=%lu, block="E3FSBLK,
2830                                        inode->i_ino, block);
2831                        brelse(bh);
2832                        return -EIO;
2833                }
2834        }
2835has_buffer:
2836        iloc->bh = bh;
2837        return 0;
2838}
2839
2840int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2841{
2842        /* We have all inode data except xattrs in memory here. */
2843        return __ext3_get_inode_loc(inode, iloc,
2844                !ext3_test_inode_state(inode, EXT3_STATE_XATTR));
2845}
2846
2847void ext3_set_inode_flags(struct inode *inode)
2848{
2849        unsigned int flags = EXT3_I(inode)->i_flags;
2850
2851        inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2852        if (flags & EXT3_SYNC_FL)
2853                inode->i_flags |= S_SYNC;
2854        if (flags & EXT3_APPEND_FL)
2855                inode->i_flags |= S_APPEND;
2856        if (flags & EXT3_IMMUTABLE_FL)
2857                inode->i_flags |= S_IMMUTABLE;
2858        if (flags & EXT3_NOATIME_FL)
2859                inode->i_flags |= S_NOATIME;
2860        if (flags & EXT3_DIRSYNC_FL)
2861                inode->i_flags |= S_DIRSYNC;
2862}
2863
2864/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2865void ext3_get_inode_flags(struct ext3_inode_info *ei)
2866{
2867        unsigned int flags = ei->vfs_inode.i_flags;
2868
2869        ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2870                        EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2871        if (flags & S_SYNC)
2872                ei->i_flags |= EXT3_SYNC_FL;
2873        if (flags & S_APPEND)
2874                ei->i_flags |= EXT3_APPEND_FL;
2875        if (flags & S_IMMUTABLE)
2876                ei->i_flags |= EXT3_IMMUTABLE_FL;
2877        if (flags & S_NOATIME)
2878                ei->i_flags |= EXT3_NOATIME_FL;
2879        if (flags & S_DIRSYNC)
2880                ei->i_flags |= EXT3_DIRSYNC_FL;
2881}
2882
2883struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2884{
2885        struct ext3_iloc iloc;
2886        struct ext3_inode *raw_inode;
2887        struct ext3_inode_info *ei;
2888        struct buffer_head *bh;
2889        struct inode *inode;
2890        journal_t *journal = EXT3_SB(sb)->s_journal;
2891        transaction_t *transaction;
2892        long ret;
2893        int block;
2894        uid_t i_uid;
2895        gid_t i_gid;
2896
2897        inode = iget_locked(sb, ino);
2898        if (!inode)
2899                return ERR_PTR(-ENOMEM);
2900        if (!(inode->i_state & I_NEW))
2901                return inode;
2902
2903        ei = EXT3_I(inode);
2904        ei->i_block_alloc_info = NULL;
2905
2906        ret = __ext3_get_inode_loc(inode, &iloc, 0);
2907        if (ret < 0)
2908                goto bad_inode;
2909        bh = iloc.bh;
2910        raw_inode = ext3_raw_inode(&iloc);
2911        inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2912        i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2913        i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2914        if(!(test_opt (inode->i_sb, NO_UID32))) {
2915                i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2916                i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2917        }
2918        i_uid_write(inode, i_uid);
2919        i_gid_write(inode, i_gid);
2920        set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
2921        inode->i_size = le32_to_cpu(raw_inode->i_size);
2922        inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2923        inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2924        inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2925        inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2926
2927        ei->i_state_flags = 0;
2928        ei->i_dir_start_lookup = 0;
2929        ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2930        /* We now have enough fields to check if the inode was active or not.
2931         * This is needed because nfsd might try to access dead inodes
2932         * the test is that same one that e2fsck uses
2933         * NeilBrown 1999oct15
2934         */
2935        if (inode->i_nlink == 0) {
2936                if (inode->i_mode == 0 ||
2937                    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2938                        /* this inode is deleted */
2939                        brelse (bh);
2940                        ret = -ESTALE;
2941                        goto bad_inode;
2942                }
2943                /* The only unlinked inodes we let through here have
2944                 * valid i_mode and are being read by the orphan
2945                 * recovery code: that's fine, we're about to complete
2946                 * the process of deleting those. */
2947        }
2948        inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2949        ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2950#ifdef EXT3_FRAGMENTS
2951        ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2952        ei->i_frag_no = raw_inode->i_frag;
2953        ei->i_frag_size = raw_inode->i_fsize;
2954#endif
2955        ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2956        if (!S_ISREG(inode->i_mode)) {
2957                ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2958        } else {
2959                inode->i_size |=
2960                        ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2961        }
2962        ei->i_disksize = inode->i_size;
2963        inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2964        ei->i_block_group = iloc.block_group;
2965        /*
2966         * NOTE! The in-memory inode i_data array is in little-endian order
2967         * even on big-endian machines: we do NOT byteswap the block numbers!
2968         */
2969        for (block = 0; block < EXT3_N_BLOCKS; block++)
2970                ei->i_data[block] = raw_inode->i_block[block];
2971        INIT_LIST_HEAD(&ei->i_orphan);
2972
2973        /*
2974         * Set transaction id's of transactions that have to be committed
2975         * to finish f[data]sync. We set them to currently running transaction
2976         * as we cannot be sure that the inode or some of its metadata isn't
2977         * part of the transaction - the inode could have been reclaimed and
2978         * now it is reread from disk.
2979         */
2980        if (journal) {
2981                tid_t tid;
2982
2983                spin_lock(&journal->j_state_lock);
2984                if (journal->j_running_transaction)
2985                        transaction = journal->j_running_transaction;
2986                else
2987                        transaction = journal->j_committing_transaction;
2988                if (transaction)
2989                        tid = transaction->t_tid;
2990                else
2991                        tid = journal->j_commit_sequence;
2992                spin_unlock(&journal->j_state_lock);
2993                atomic_set(&ei->i_sync_tid, tid);
2994                atomic_set(&ei->i_datasync_tid, tid);
2995        }
2996
2997        if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2998            EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2999                /*
3000                 * When mke2fs creates big inodes it does not zero out
3001                 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
3002                 * so ignore those first few inodes.
3003                 */
3004                ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
3005                if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
3006                    EXT3_INODE_SIZE(inode->i_sb)) {
3007                        brelse (bh);
3008                        ret = -EIO;
3009                        goto bad_inode;
3010                }
3011                if (ei->i_extra_isize == 0) {
3012                        /* The extra space is currently unused. Use it. */
3013                        ei->i_extra_isize = sizeof(struct ext3_inode) -
3014                                            EXT3_GOOD_OLD_INODE_SIZE;
3015                } else {
3016                        __le32 *magic = (void *)raw_inode +
3017                                        EXT3_GOOD_OLD_INODE_SIZE +
3018                                        ei->i_extra_isize;
3019                        if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
3020                                 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
3021                }
3022        } else
3023                ei->i_extra_isize = 0;
3024
3025        if (S_ISREG(inode->i_mode)) {
3026                inode->i_op = &ext3_file_inode_operations;
3027                inode->i_fop = &ext3_file_operations;
3028                ext3_set_aops(inode);
3029        } else if (S_ISDIR(inode->i_mode)) {
3030                inode->i_op = &ext3_dir_inode_operations;
3031                inode->i_fop = &ext3_dir_operations;
3032        } else if (S_ISLNK(inode->i_mode)) {
3033                if (ext3_inode_is_fast_symlink(inode)) {
3034                        inode->i_op = &ext3_fast_symlink_inode_operations;
3035                        nd_terminate_link(ei->i_data, inode->i_size,
3036                                sizeof(ei->i_data) - 1);
3037                } else {
3038                        inode->i_op = &ext3_symlink_inode_operations;
3039                        ext3_set_aops(inode);
3040                }
3041        } else {
3042                inode->i_op = &ext3_special_inode_operations;
3043                if (raw_inode->i_block[0])
3044                        init_special_inode(inode, inode->i_mode,
3045                           old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3046                else
3047                        init_special_inode(inode, inode->i_mode,
3048                           new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3049        }
3050        brelse (iloc.bh);
3051        ext3_set_inode_flags(inode);
3052        unlock_new_inode(inode);
3053        return inode;
3054
3055bad_inode:
3056        iget_failed(inode);
3057        return ERR_PTR(ret);
3058}
3059
3060/*
3061 * Post the struct inode info into an on-disk inode location in the
3062 * buffer-cache.  This gobbles the caller's reference to the
3063 * buffer_head in the inode location struct.
3064 *
3065 * The caller must have write access to iloc->bh.
3066 */
3067static int ext3_do_update_inode(handle_t *handle,
3068                                struct inode *inode,
3069                                struct ext3_iloc *iloc)
3070{
3071        struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
3072        struct ext3_inode_info *ei = EXT3_I(inode);
3073        struct buffer_head *bh = iloc->bh;
3074        int err = 0, rc, block;
3075        int need_datasync = 0;
3076        __le32 disksize;
3077        uid_t i_uid;
3078        gid_t i_gid;
3079
3080again:
3081        /* we can't allow multiple procs in here at once, its a bit racey */
3082        lock_buffer(bh);
3083
3084        /* For fields not not tracking in the in-memory inode,
3085         * initialise them to zero for new inodes. */
3086        if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
3087                memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
3088
3089        ext3_get_inode_flags(ei);
3090        raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3091        i_uid = i_uid_read(inode);
3092        i_gid = i_gid_read(inode);
3093        if(!(test_opt(inode->i_sb, NO_UID32))) {
3094                raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
3095                raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
3096/*
3097 * Fix up interoperability with old kernels. Otherwise, old inodes get
3098 * re-used with the upper 16 bits of the uid/gid intact
3099 */
3100                if(!ei->i_dtime) {
3101                        raw_inode->i_uid_high =
3102                                cpu_to_le16(high_16_bits(i_uid));
3103                        raw_inode->i_gid_high =
3104                                cpu_to_le16(high_16_bits(i_gid));
3105                } else {
3106                        raw_inode->i_uid_high = 0;
3107                        raw_inode->i_gid_high = 0;
3108                }
3109        } else {
3110                raw_inode->i_uid_low =
3111                        cpu_to_le16(fs_high2lowuid(i_uid));
3112                raw_inode->i_gid_low =
3113                        cpu_to_le16(fs_high2lowgid(i_gid));
3114                raw_inode->i_uid_high = 0;
3115                raw_inode->i_gid_high = 0;
3116        }
3117        raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3118        disksize = cpu_to_le32(ei->i_disksize);
3119        if (disksize != raw_inode->i_size) {
3120                need_datasync = 1;
3121                raw_inode->i_size = disksize;
3122        }
3123        raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
3124        raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
3125        raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
3126        raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
3127        raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3128        raw_inode->i_flags = cpu_to_le32(ei->i_flags);
3129#ifdef EXT3_FRAGMENTS
3130        raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
3131        raw_inode->i_frag = ei->i_frag_no;
3132        raw_inode->i_fsize = ei->i_frag_size;
3133#endif
3134        raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
3135        if (!S_ISREG(inode->i_mode)) {
3136                raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
3137        } else {
3138                disksize = cpu_to_le32(ei->i_disksize >> 32);
3139                if (disksize != raw_inode->i_size_high) {
3140                        raw_inode->i_size_high = disksize;
3141                        need_datasync = 1;
3142                }
3143                if (ei->i_disksize > 0x7fffffffULL) {
3144                        struct super_block *sb = inode->i_sb;
3145                        if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
3146                                        EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
3147                            EXT3_SB(sb)->s_es->s_rev_level ==
3148                                        cpu_to_le32(EXT3_GOOD_OLD_REV)) {
3149                               /* If this is the first large file
3150                                * created, add a flag to the superblock.
3151                                */
3152                                unlock_buffer(bh);
3153                                err = ext3_journal_get_write_access(handle,
3154                                                EXT3_SB(sb)->s_sbh);
3155                                if (err)
3156                                        goto out_brelse;
3157
3158                                ext3_update_dynamic_rev(sb);
3159                                EXT3_SET_RO_COMPAT_FEATURE(sb,
3160                                        EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
3161                                handle->h_sync = 1;
3162                                err = ext3_journal_dirty_metadata(handle,
3163                                                EXT3_SB(sb)->s_sbh);
3164                                /* get our lock and start over */
3165                                goto again;
3166                        }
3167                }
3168        }
3169        raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3170        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3171                if (old_valid_dev(inode->i_rdev)) {
3172                        raw_inode->i_block[0] =
3173                                cpu_to_le32(old_encode_dev(inode->i_rdev));
3174                        raw_inode->i_block[1] = 0;
3175                } else {
3176                        raw_inode->i_block[0] = 0;
3177                        raw_inode->i_block[1] =
3178                                cpu_to_le32(new_encode_dev(inode->i_rdev));
3179                        raw_inode->i_block[2] = 0;
3180                }
3181        } else for (block = 0; block < EXT3_N_BLOCKS; block++)
3182                raw_inode->i_block[block] = ei->i_data[block];
3183
3184        if (ei->i_extra_isize)
3185                raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3186
3187        BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
3188        unlock_buffer(bh);
3189        rc = ext3_journal_dirty_metadata(handle, bh);
3190        if (!err)
3191                err = rc;
3192        ext3_clear_inode_state(inode, EXT3_STATE_NEW);
3193
3194        atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
3195        if (need_datasync)
3196                atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
3197out_brelse:
3198        brelse (bh);
3199        ext3_std_error(inode->i_sb, err);
3200        return err;
3201}
3202
3203/*
3204 * ext3_write_inode()
3205 *
3206 * We are called from a few places:
3207 *
3208 * - Within generic_file_write() for O_SYNC files.
3209 *   Here, there will be no transaction running. We wait for any running
3210 *   trasnaction to commit.
3211 *
3212 * - Within sys_sync(), kupdate and such.
3213 *   We wait on commit, if tol to.
3214 *
3215 * - Within prune_icache() (PF_MEMALLOC == true)
3216 *   Here we simply return.  We can't afford to block kswapd on the
3217 *   journal commit.
3218 *
3219 * In all cases it is actually safe for us to return without doing anything,
3220 * because the inode has been copied into a raw inode buffer in
3221 * ext3_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
3222 * knfsd.
3223 *
3224 * Note that we are absolutely dependent upon all inode dirtiers doing the
3225 * right thing: they *must* call mark_inode_dirty() after dirtying info in
3226 * which we are interested.
3227 *
3228 * It would be a bug for them to not do this.  The code:
3229 *
3230 *      mark_inode_dirty(inode)
3231 *      stuff();
3232 *      inode->i_size = expr;
3233 *
3234 * is in error because a kswapd-driven write_inode() could occur while
3235 * `stuff()' is running, and the new i_size will be lost.  Plus the inode
3236 * will no longer be on the superblock's dirty inode list.
3237 */
3238int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
3239{
3240        if (current->flags & PF_MEMALLOC)
3241                return 0;
3242
3243        if (ext3_journal_current_handle()) {
3244                jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3245                dump_stack();
3246                return -EIO;
3247        }
3248
3249        if (wbc->sync_mode != WB_SYNC_ALL)
3250                return 0;
3251
3252        return ext3_force_commit(inode->i_sb);
3253}
3254
3255/*
3256 * ext3_setattr()
3257 *
3258 * Called from notify_change.
3259 *
3260 * We want to trap VFS attempts to truncate the file as soon as
3261 * possible.  In particular, we want to make sure that when the VFS
3262 * shrinks i_size, we put the inode on the orphan list and modify
3263 * i_disksize immediately, so that during the subsequent flushing of
3264 * dirty pages and freeing of disk blocks, we can guarantee that any
3265 * commit will leave the blocks being flushed in an unused state on
3266 * disk.  (On recovery, the inode will get truncated and the blocks will
3267 * be freed, so we have a strong guarantee that no future commit will
3268 * leave these blocks visible to the user.)
3269 *
3270 * Called with inode->sem down.
3271 */
3272int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3273{
3274        struct inode *inode = dentry->d_inode;
3275        int error, rc = 0;
3276        const unsigned int ia_valid = attr->ia_valid;
3277
3278        error = inode_change_ok(inode, attr);
3279        if (error)
3280                return error;
3281
3282        if (is_quota_modification(inode, attr))
3283                dquot_initialize(inode);
3284        if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
3285            (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
3286                handle_t *handle;
3287
3288                /* (user+group)*(old+new) structure, inode write (sb,
3289                 * inode block, ? - but truncate inode update has it) */
3290                handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3291                                        EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
3292                if (IS_ERR(handle)) {
3293                        error = PTR_ERR(handle);
3294                        goto err_out;
3295                }
3296                error = dquot_transfer(inode, attr);
3297                if (error) {
3298                        ext3_journal_stop(handle);
3299                        return error;
3300                }
3301                /* Update corresponding info in inode so that everything is in
3302                 * one transaction */
3303                if (attr->ia_valid & ATTR_UID)
3304                        inode->i_uid = attr->ia_uid;
3305                if (attr->ia_valid & ATTR_GID)
3306                        inode->i_gid = attr->ia_gid;
3307                error = ext3_mark_inode_dirty(handle, inode);
3308                ext3_journal_stop(handle);
3309        }
3310
3311        if (attr->ia_valid & ATTR_SIZE)
3312                inode_dio_wait(inode);
3313
3314        if (S_ISREG(inode->i_mode) &&
3315            attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3316                handle_t *handle;
3317
3318                handle = ext3_journal_start(inode, 3);
3319                if (IS_ERR(handle)) {
3320                        error = PTR_ERR(handle);
3321                        goto err_out;
3322                }
3323
3324                error = ext3_orphan_add(handle, inode);
3325                if (error) {
3326                        ext3_journal_stop(handle);
3327                        goto err_out;
3328                }
3329                EXT3_I(inode)->i_disksize = attr->ia_size;
3330                error = ext3_mark_inode_dirty(handle, inode);
3331                ext3_journal_stop(handle);
3332                if (error) {
3333                        /* Some hard fs error must have happened. Bail out. */
3334                        ext3_orphan_del(NULL, inode);
3335                        goto err_out;
3336                }
3337                rc = ext3_block_truncate_page(inode, attr->ia_size);
3338                if (rc) {
3339                        /* Cleanup orphan list and exit */
3340                        handle = ext3_journal_start(inode, 3);
3341                        if (IS_ERR(handle)) {
3342                                ext3_orphan_del(NULL, inode);
3343                                goto err_out;
3344                        }
3345                        ext3_orphan_del(handle, inode);
3346                        ext3_journal_stop(handle);
3347                        goto err_out;
3348                }
3349        }
3350
3351        if ((attr->ia_valid & ATTR_SIZE) &&
3352            attr->ia_size != i_size_read(inode)) {
3353                truncate_setsize(inode, attr->ia_size);
3354                ext3_truncate(inode);
3355        }
3356
3357        setattr_copy(inode, attr);
3358        mark_inode_dirty(inode);
3359
3360        if (ia_valid & ATTR_MODE)
3361                rc = ext3_acl_chmod(inode);
3362
3363err_out:
3364        ext3_std_error(inode->i_sb, error);
3365        if (!error)
3366                error = rc;
3367        return error;
3368}
3369
3370
3371/*
3372 * How many blocks doth make a writepage()?
3373 *
3374 * With N blocks per page, it may be:
3375 * N data blocks
3376 * 2 indirect block
3377 * 2 dindirect
3378 * 1 tindirect
3379 * N+5 bitmap blocks (from the above)
3380 * N+5 group descriptor summary blocks
3381 * 1 inode block
3382 * 1 superblock.
3383 * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3384 *
3385 * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3386 *
3387 * With ordered or writeback data it's the same, less the N data blocks.
3388 *
3389 * If the inode's direct blocks can hold an integral number of pages then a
3390 * page cannot straddle two indirect blocks, and we can only touch one indirect
3391 * and dindirect block, and the "5" above becomes "3".
3392 *
3393 * This still overestimates under most circumstances.  If we were to pass the
3394 * start and end offsets in here as well we could do block_to_path() on each
3395 * block and work out the exact number of indirects which are touched.  Pah.
3396 */
3397
3398static int ext3_writepage_trans_blocks(struct inode *inode)
3399{
3400        int bpp = ext3_journal_blocks_per_page(inode);
3401        int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3402        int ret;
3403
3404        if (ext3_should_journal_data(inode))
3405                ret = 3 * (bpp + indirects) + 2;
3406        else
3407                ret = 2 * (bpp + indirects) + indirects + 2;
3408
3409#ifdef CONFIG_QUOTA
3410        /* We know that structure was already allocated during dquot_initialize so
3411         * we will be updating only the data blocks + inodes */
3412        ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
3413#endif
3414
3415        return ret;
3416}
3417
3418/*
3419 * The caller must have previously called ext3_reserve_inode_write().
3420 * Give this, we know that the caller already has write access to iloc->bh.
3421 */
3422int ext3_mark_iloc_dirty(handle_t *handle,
3423                struct inode *inode, struct ext3_iloc *iloc)
3424{
3425        int err = 0;
3426
3427        /* the do_update_inode consumes one bh->b_count */
3428        get_bh(iloc->bh);
3429
3430        /* ext3_do_update_inode() does journal_dirty_metadata */
3431        err = ext3_do_update_inode(handle, inode, iloc);
3432        put_bh(iloc->bh);
3433        return err;
3434}
3435
3436/*
3437 * On success, We end up with an outstanding reference count against
3438 * iloc->bh.  This _must_ be cleaned up later.
3439 */
3440
3441int
3442ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3443                         struct ext3_iloc *iloc)
3444{
3445        int err = 0;
3446        if (handle) {
3447                err = ext3_get_inode_loc(inode, iloc);
3448                if (!err) {
3449                        BUFFER_TRACE(iloc->bh, "get_write_access");
3450                        err = ext3_journal_get_write_access(handle, iloc->bh);
3451                        if (err) {
3452                                brelse(iloc->bh);
3453                                iloc->bh = NULL;
3454                        }
3455                }
3456        }
3457        ext3_std_error(inode->i_sb, err);
3458        return err;
3459}
3460
3461/*
3462 * What we do here is to mark the in-core inode as clean with respect to inode
3463 * dirtiness (it may still be data-dirty).
3464 * This means that the in-core inode may be reaped by prune_icache
3465 * without having to perform any I/O.  This is a very good thing,
3466 * because *any* task may call prune_icache - even ones which
3467 * have a transaction open against a different journal.
3468 *
3469 * Is this cheating?  Not really.  Sure, we haven't written the
3470 * inode out, but prune_icache isn't a user-visible syncing function.
3471 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3472 * we start and wait on commits.
3473 */
3474int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3475{
3476        struct ext3_iloc iloc;
3477        int err;
3478
3479        might_sleep();
3480        trace_ext3_mark_inode_dirty(inode, _RET_IP_);
3481        err = ext3_reserve_inode_write(handle, inode, &iloc);
3482        if (!err)
3483                err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3484        return err;
3485}
3486
3487/*
3488 * ext3_dirty_inode() is called from __mark_inode_dirty()
3489 *
3490 * We're really interested in the case where a file is being extended.
3491 * i_size has been changed by generic_commit_write() and we thus need
3492 * to include the updated inode in the current transaction.
3493 *
3494 * Also, dquot_alloc_space() will always dirty the inode when blocks
3495 * are allocated to the file.
3496 *
3497 * If the inode is marked synchronous, we don't honour that here - doing
3498 * so would cause a commit on atime updates, which we don't bother doing.
3499 * We handle synchronous inodes at the highest possible level.
3500 */
3501void ext3_dirty_inode(struct inode *inode, int flags)
3502{
3503        handle_t *current_handle = ext3_journal_current_handle();
3504        handle_t *handle;
3505
3506        handle = ext3_journal_start(inode, 2);
3507        if (IS_ERR(handle))
3508                goto out;
3509        if (current_handle &&
3510                current_handle->h_transaction != handle->h_transaction) {
3511                /* This task has a transaction open against a different fs */
3512                printk(KERN_EMERG "%s: transactions do not match!\n",
3513                       __func__);
3514        } else {
3515                jbd_debug(5, "marking dirty.  outer handle=%p\n",
3516                                current_handle);
3517                ext3_mark_inode_dirty(handle, inode);
3518        }
3519        ext3_journal_stop(handle);
3520out:
3521        return;
3522}
3523
3524#if 0
3525/*
3526 * Bind an inode's backing buffer_head into this transaction, to prevent
3527 * it from being flushed to disk early.  Unlike
3528 * ext3_reserve_inode_write, this leaves behind no bh reference and
3529 * returns no iloc structure, so the caller needs to repeat the iloc
3530 * lookup to mark the inode dirty later.
3531 */
3532static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3533{
3534        struct ext3_iloc iloc;
3535
3536        int err = 0;
3537        if (handle) {
3538                err = ext3_get_inode_loc(inode, &iloc);
3539                if (!err) {
3540                        BUFFER_TRACE(iloc.bh, "get_write_access");
3541                        err = journal_get_write_access(handle, iloc.bh);
3542                        if (!err)
3543                                err = ext3_journal_dirty_metadata(handle,
3544                                                                  iloc.bh);
3545                        brelse(iloc.bh);
3546                }
3547        }
3548        ext3_std_error(inode->i_sb, err);
3549        return err;
3550}
3551#endif
3552
3553int ext3_change_inode_journal_flag(struct inode *inode, int val)
3554{
3555        journal_t *journal;
3556        handle_t *handle;
3557        int err;
3558
3559        /*
3560         * We have to be very careful here: changing a data block's
3561         * journaling status dynamically is dangerous.  If we write a
3562         * data block to the journal, change the status and then delete
3563         * that block, we risk forgetting to revoke the old log record
3564         * from the journal and so a subsequent replay can corrupt data.
3565         * So, first we make sure that the journal is empty and that
3566         * nobody is changing anything.
3567         */
3568
3569        journal = EXT3_JOURNAL(inode);
3570        if (is_journal_aborted(journal))
3571                return -EROFS;
3572
3573        journal_lock_updates(journal);
3574        journal_flush(journal);
3575
3576        /*
3577         * OK, there are no updates running now, and all cached data is
3578         * synced to disk.  We are now in a completely consistent state
3579         * which doesn't have anything in the journal, and we know that
3580         * no filesystem updates are running, so it is safe to modify
3581         * the inode's in-core data-journaling state flag now.
3582         */
3583
3584        if (val)
3585                EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3586        else
3587                EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3588        ext3_set_aops(inode);
3589
3590        journal_unlock_updates(journal);
3591
3592        /* Finally we can mark the inode as dirty. */
3593
3594        handle = ext3_journal_start(inode, 1);
3595        if (IS_ERR(handle))
3596                return PTR_ERR(handle);
3597
3598        err = ext3_mark_inode_dirty(handle, inode);
3599        handle->h_sync = 1;
3600        ext3_journal_stop(handle);
3601        ext3_std_error(inode->i_sb, err);
3602
3603        return err;
3604}
3605
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