linux/fs/ext2/inode.c
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   1/*
   2 *  linux/fs/ext2/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@dcs.ed.ac.uk), 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 ext2_get_block() by Al Viro, 2000
  23 */
  24
  25#include <linux/time.h>
  26#include <linux/highuid.h>
  27#include <linux/pagemap.h>
  28#include <linux/dax.h>
  29#include <linux/blkdev.h>
  30#include <linux/quotaops.h>
  31#include <linux/writeback.h>
  32#include <linux/buffer_head.h>
  33#include <linux/mpage.h>
  34#include <linux/fiemap.h>
  35#include <linux/namei.h>
  36#include <linux/uio.h>
  37#include "ext2.h"
  38#include "acl.h"
  39#include "xattr.h"
  40
  41static int __ext2_write_inode(struct inode *inode, int do_sync);
  42
  43/*
  44 * Test whether an inode is a fast symlink.
  45 */
  46static inline int ext2_inode_is_fast_symlink(struct inode *inode)
  47{
  48        int ea_blocks = EXT2_I(inode)->i_file_acl ?
  49                (inode->i_sb->s_blocksize >> 9) : 0;
  50
  51        return (S_ISLNK(inode->i_mode) &&
  52                inode->i_blocks - ea_blocks == 0);
  53}
  54
  55static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
  56
  57static void ext2_write_failed(struct address_space *mapping, loff_t to)
  58{
  59        struct inode *inode = mapping->host;
  60
  61        if (to > inode->i_size) {
  62                truncate_pagecache(inode, inode->i_size);
  63                ext2_truncate_blocks(inode, inode->i_size);
  64        }
  65}
  66
  67/*
  68 * Called at the last iput() if i_nlink is zero.
  69 */
  70void ext2_evict_inode(struct inode * inode)
  71{
  72        struct ext2_block_alloc_info *rsv;
  73        int want_delete = 0;
  74
  75        if (!inode->i_nlink && !is_bad_inode(inode)) {
  76                want_delete = 1;
  77                dquot_initialize(inode);
  78        } else {
  79                dquot_drop(inode);
  80        }
  81
  82        truncate_inode_pages_final(&inode->i_data);
  83
  84        if (want_delete) {
  85                sb_start_intwrite(inode->i_sb);
  86                /* set dtime */
  87                EXT2_I(inode)->i_dtime  = get_seconds();
  88                mark_inode_dirty(inode);
  89                __ext2_write_inode(inode, inode_needs_sync(inode));
  90                /* truncate to 0 */
  91                inode->i_size = 0;
  92                if (inode->i_blocks)
  93                        ext2_truncate_blocks(inode, 0);
  94                ext2_xattr_delete_inode(inode);
  95        }
  96
  97        invalidate_inode_buffers(inode);
  98        clear_inode(inode);
  99
 100        ext2_discard_reservation(inode);
 101        rsv = EXT2_I(inode)->i_block_alloc_info;
 102        EXT2_I(inode)->i_block_alloc_info = NULL;
 103        if (unlikely(rsv))
 104                kfree(rsv);
 105
 106        if (want_delete) {
 107                ext2_free_inode(inode);
 108                sb_end_intwrite(inode->i_sb);
 109        }
 110}
 111
 112typedef struct {
 113        __le32  *p;
 114        __le32  key;
 115        struct buffer_head *bh;
 116} Indirect;
 117
 118static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
 119{
 120        p->key = *(p->p = v);
 121        p->bh = bh;
 122}
 123
 124static inline int verify_chain(Indirect *from, Indirect *to)
 125{
 126        while (from <= to && from->key == *from->p)
 127                from++;
 128        return (from > to);
 129}
 130
 131/**
 132 *      ext2_block_to_path - parse the block number into array of offsets
 133 *      @inode: inode in question (we are only interested in its superblock)
 134 *      @i_block: block number to be parsed
 135 *      @offsets: array to store the offsets in
 136 *      @boundary: set this non-zero if the referred-to block is likely to be
 137 *             followed (on disk) by an indirect block.
 138 *      To store the locations of file's data ext2 uses a data structure common
 139 *      for UNIX filesystems - tree of pointers anchored in the inode, with
 140 *      data blocks at leaves and indirect blocks in intermediate nodes.
 141 *      This function translates the block number into path in that tree -
 142 *      return value is the path length and @offsets[n] is the offset of
 143 *      pointer to (n+1)th node in the nth one. If @block is out of range
 144 *      (negative or too large) warning is printed and zero returned.
 145 *
 146 *      Note: function doesn't find node addresses, so no IO is needed. All
 147 *      we need to know is the capacity of indirect blocks (taken from the
 148 *      inode->i_sb).
 149 */
 150
 151/*
 152 * Portability note: the last comparison (check that we fit into triple
 153 * indirect block) is spelled differently, because otherwise on an
 154 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 155 * if our filesystem had 8Kb blocks. We might use long long, but that would
 156 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 157 * i_block would have to be negative in the very beginning, so we would not
 158 * get there at all.
 159 */
 160
 161static int ext2_block_to_path(struct inode *inode,
 162                        long i_block, int offsets[4], int *boundary)
 163{
 164        int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
 165        int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
 166        const long direct_blocks = EXT2_NDIR_BLOCKS,
 167                indirect_blocks = ptrs,
 168                double_blocks = (1 << (ptrs_bits * 2));
 169        int n = 0;
 170        int final = 0;
 171
 172        if (i_block < 0) {
 173                ext2_msg(inode->i_sb, KERN_WARNING,
 174                        "warning: %s: block < 0", __func__);
 175        } else if (i_block < direct_blocks) {
 176                offsets[n++] = i_block;
 177                final = direct_blocks;
 178        } else if ( (i_block -= direct_blocks) < indirect_blocks) {
 179                offsets[n++] = EXT2_IND_BLOCK;
 180                offsets[n++] = i_block;
 181                final = ptrs;
 182        } else if ((i_block -= indirect_blocks) < double_blocks) {
 183                offsets[n++] = EXT2_DIND_BLOCK;
 184                offsets[n++] = i_block >> ptrs_bits;
 185                offsets[n++] = i_block & (ptrs - 1);
 186                final = ptrs;
 187        } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
 188                offsets[n++] = EXT2_TIND_BLOCK;
 189                offsets[n++] = i_block >> (ptrs_bits * 2);
 190                offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
 191                offsets[n++] = i_block & (ptrs - 1);
 192                final = ptrs;
 193        } else {
 194                ext2_msg(inode->i_sb, KERN_WARNING,
 195                        "warning: %s: block is too big", __func__);
 196        }
 197        if (boundary)
 198                *boundary = final - 1 - (i_block & (ptrs - 1));
 199
 200        return n;
 201}
 202
 203/**
 204 *      ext2_get_branch - read the chain of indirect blocks leading to data
 205 *      @inode: inode in question
 206 *      @depth: depth of the chain (1 - direct pointer, etc.)
 207 *      @offsets: offsets of pointers in inode/indirect blocks
 208 *      @chain: place to store the result
 209 *      @err: here we store the error value
 210 *
 211 *      Function fills the array of triples <key, p, bh> and returns %NULL
 212 *      if everything went OK or the pointer to the last filled triple
 213 *      (incomplete one) otherwise. Upon the return chain[i].key contains
 214 *      the number of (i+1)-th block in the chain (as it is stored in memory,
 215 *      i.e. little-endian 32-bit), chain[i].p contains the address of that
 216 *      number (it points into struct inode for i==0 and into the bh->b_data
 217 *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 218 *      block for i>0 and NULL for i==0. In other words, it holds the block
 219 *      numbers of the chain, addresses they were taken from (and where we can
 220 *      verify that chain did not change) and buffer_heads hosting these
 221 *      numbers.
 222 *
 223 *      Function stops when it stumbles upon zero pointer (absent block)
 224 *              (pointer to last triple returned, *@err == 0)
 225 *      or when it gets an IO error reading an indirect block
 226 *              (ditto, *@err == -EIO)
 227 *      or when it notices that chain had been changed while it was reading
 228 *              (ditto, *@err == -EAGAIN)
 229 *      or when it reads all @depth-1 indirect blocks successfully and finds
 230 *      the whole chain, all way to the data (returns %NULL, *err == 0).
 231 */
 232static Indirect *ext2_get_branch(struct inode *inode,
 233                                 int depth,
 234                                 int *offsets,
 235                                 Indirect chain[4],
 236                                 int *err)
 237{
 238        struct super_block *sb = inode->i_sb;
 239        Indirect *p = chain;
 240        struct buffer_head *bh;
 241
 242        *err = 0;
 243        /* i_data is not going away, no lock needed */
 244        add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
 245        if (!p->key)
 246                goto no_block;
 247        while (--depth) {
 248                bh = sb_bread(sb, le32_to_cpu(p->key));
 249                if (!bh)
 250                        goto failure;
 251                read_lock(&EXT2_I(inode)->i_meta_lock);
 252                if (!verify_chain(chain, p))
 253                        goto changed;
 254                add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
 255                read_unlock(&EXT2_I(inode)->i_meta_lock);
 256                if (!p->key)
 257                        goto no_block;
 258        }
 259        return NULL;
 260
 261changed:
 262        read_unlock(&EXT2_I(inode)->i_meta_lock);
 263        brelse(bh);
 264        *err = -EAGAIN;
 265        goto no_block;
 266failure:
 267        *err = -EIO;
 268no_block:
 269        return p;
 270}
 271
 272/**
 273 *      ext2_find_near - find a place for allocation with sufficient locality
 274 *      @inode: owner
 275 *      @ind: descriptor of indirect block.
 276 *
 277 *      This function returns the preferred place for block allocation.
 278 *      It is used when heuristic for sequential allocation fails.
 279 *      Rules are:
 280 *        + if there is a block to the left of our position - allocate near it.
 281 *        + if pointer will live in indirect block - allocate near that block.
 282 *        + if pointer will live in inode - allocate in the same cylinder group.
 283 *
 284 * In the latter case we colour the starting block by the callers PID to
 285 * prevent it from clashing with concurrent allocations for a different inode
 286 * in the same block group.   The PID is used here so that functionally related
 287 * files will be close-by on-disk.
 288 *
 289 *      Caller must make sure that @ind is valid and will stay that way.
 290 */
 291
 292static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
 293{
 294        struct ext2_inode_info *ei = EXT2_I(inode);
 295        __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
 296        __le32 *p;
 297        ext2_fsblk_t bg_start;
 298        ext2_fsblk_t colour;
 299
 300        /* Try to find previous block */
 301        for (p = ind->p - 1; p >= start; p--)
 302                if (*p)
 303                        return le32_to_cpu(*p);
 304
 305        /* No such thing, so let's try location of indirect block */
 306        if (ind->bh)
 307                return ind->bh->b_blocknr;
 308
 309        /*
 310         * It is going to be referred from inode itself? OK, just put it into
 311         * the same cylinder group then.
 312         */
 313        bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
 314        colour = (current->pid % 16) *
 315                        (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 316        return bg_start + colour;
 317}
 318
 319/**
 320 *      ext2_find_goal - find a preferred place for allocation.
 321 *      @inode: owner
 322 *      @block:  block we want
 323 *      @partial: pointer to the last triple within a chain
 324 *
 325 *      Returns preferred place for a block (the goal).
 326 */
 327
 328static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
 329                                          Indirect *partial)
 330{
 331        struct ext2_block_alloc_info *block_i;
 332
 333        block_i = EXT2_I(inode)->i_block_alloc_info;
 334
 335        /*
 336         * try the heuristic for sequential allocation,
 337         * failing that at least try to get decent locality.
 338         */
 339        if (block_i && (block == block_i->last_alloc_logical_block + 1)
 340                && (block_i->last_alloc_physical_block != 0)) {
 341                return block_i->last_alloc_physical_block + 1;
 342        }
 343
 344        return ext2_find_near(inode, partial);
 345}
 346
 347/**
 348 *      ext2_blks_to_allocate: Look up the block map and count the number
 349 *      of direct blocks need to be allocated for the given branch.
 350 *
 351 *      @branch: chain of indirect blocks
 352 *      @k: number of blocks need for indirect blocks
 353 *      @blks: number of data blocks to be mapped.
 354 *      @blocks_to_boundary:  the offset in the indirect block
 355 *
 356 *      return the total number of blocks to be allocate, including the
 357 *      direct and indirect blocks.
 358 */
 359static int
 360ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
 361                int blocks_to_boundary)
 362{
 363        unsigned long count = 0;
 364
 365        /*
 366         * Simple case, [t,d]Indirect block(s) has not allocated yet
 367         * then it's clear blocks on that path have not allocated
 368         */
 369        if (k > 0) {
 370                /* right now don't hanel cross boundary allocation */
 371                if (blks < blocks_to_boundary + 1)
 372                        count += blks;
 373                else
 374                        count += blocks_to_boundary + 1;
 375                return count;
 376        }
 377
 378        count++;
 379        while (count < blks && count <= blocks_to_boundary
 380                && le32_to_cpu(*(branch[0].p + count)) == 0) {
 381                count++;
 382        }
 383        return count;
 384}
 385
 386/**
 387 *      ext2_alloc_blocks: multiple allocate blocks needed for a branch
 388 *      @indirect_blks: the number of blocks need to allocate for indirect
 389 *                      blocks
 390 *
 391 *      @new_blocks: on return it will store the new block numbers for
 392 *      the indirect blocks(if needed) and the first direct block,
 393 *      @blks:  on return it will store the total number of allocated
 394 *              direct blocks
 395 */
 396static int ext2_alloc_blocks(struct inode *inode,
 397                        ext2_fsblk_t goal, int indirect_blks, int blks,
 398                        ext2_fsblk_t new_blocks[4], int *err)
 399{
 400        int target, i;
 401        unsigned long count = 0;
 402        int index = 0;
 403        ext2_fsblk_t current_block = 0;
 404        int ret = 0;
 405
 406        /*
 407         * Here we try to allocate the requested multiple blocks at once,
 408         * on a best-effort basis.
 409         * To build a branch, we should allocate blocks for
 410         * the indirect blocks(if not allocated yet), and at least
 411         * the first direct block of this branch.  That's the
 412         * minimum number of blocks need to allocate(required)
 413         */
 414        target = blks + indirect_blks;
 415
 416        while (1) {
 417                count = target;
 418                /* allocating blocks for indirect blocks and direct blocks */
 419                current_block = ext2_new_blocks(inode,goal,&count,err);
 420                if (*err)
 421                        goto failed_out;
 422
 423                target -= count;
 424                /* allocate blocks for indirect blocks */
 425                while (index < indirect_blks && count) {
 426                        new_blocks[index++] = current_block++;
 427                        count--;
 428                }
 429
 430                if (count > 0)
 431                        break;
 432        }
 433
 434        /* save the new block number for the first direct block */
 435        new_blocks[index] = current_block;
 436
 437        /* total number of blocks allocated for direct blocks */
 438        ret = count;
 439        *err = 0;
 440        return ret;
 441failed_out:
 442        for (i = 0; i <index; i++)
 443                ext2_free_blocks(inode, new_blocks[i], 1);
 444        if (index)
 445                mark_inode_dirty(inode);
 446        return ret;
 447}
 448
 449/**
 450 *      ext2_alloc_branch - allocate and set up a chain of blocks.
 451 *      @inode: owner
 452 *      @num: depth of the chain (number of blocks to allocate)
 453 *      @offsets: offsets (in the blocks) to store the pointers to next.
 454 *      @branch: place to store the chain in.
 455 *
 456 *      This function allocates @num blocks, zeroes out all but the last one,
 457 *      links them into chain and (if we are synchronous) writes them to disk.
 458 *      In other words, it prepares a branch that can be spliced onto the
 459 *      inode. It stores the information about that chain in the branch[], in
 460 *      the same format as ext2_get_branch() would do. We are calling it after
 461 *      we had read the existing part of chain and partial points to the last
 462 *      triple of that (one with zero ->key). Upon the exit we have the same
 463 *      picture as after the successful ext2_get_block(), except that in one
 464 *      place chain is disconnected - *branch->p is still zero (we did not
 465 *      set the last link), but branch->key contains the number that should
 466 *      be placed into *branch->p to fill that gap.
 467 *
 468 *      If allocation fails we free all blocks we've allocated (and forget
 469 *      their buffer_heads) and return the error value the from failed
 470 *      ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 471 *      as described above and return 0.
 472 */
 473
 474static int ext2_alloc_branch(struct inode *inode,
 475                        int indirect_blks, int *blks, ext2_fsblk_t goal,
 476                        int *offsets, Indirect *branch)
 477{
 478        int blocksize = inode->i_sb->s_blocksize;
 479        int i, n = 0;
 480        int err = 0;
 481        struct buffer_head *bh;
 482        int num;
 483        ext2_fsblk_t new_blocks[4];
 484        ext2_fsblk_t current_block;
 485
 486        num = ext2_alloc_blocks(inode, goal, indirect_blks,
 487                                *blks, new_blocks, &err);
 488        if (err)
 489                return err;
 490
 491        branch[0].key = cpu_to_le32(new_blocks[0]);
 492        /*
 493         * metadata blocks and data blocks are allocated.
 494         */
 495        for (n = 1; n <= indirect_blks;  n++) {
 496                /*
 497                 * Get buffer_head for parent block, zero it out
 498                 * and set the pointer to new one, then send
 499                 * parent to disk.
 500                 */
 501                bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 502                if (unlikely(!bh)) {
 503                        err = -ENOMEM;
 504                        goto failed;
 505                }
 506                branch[n].bh = bh;
 507                lock_buffer(bh);
 508                memset(bh->b_data, 0, blocksize);
 509                branch[n].p = (__le32 *) bh->b_data + offsets[n];
 510                branch[n].key = cpu_to_le32(new_blocks[n]);
 511                *branch[n].p = branch[n].key;
 512                if ( n == indirect_blks) {
 513                        current_block = new_blocks[n];
 514                        /*
 515                         * End of chain, update the last new metablock of
 516                         * the chain to point to the new allocated
 517                         * data blocks numbers
 518                         */
 519                        for (i=1; i < num; i++)
 520                                *(branch[n].p + i) = cpu_to_le32(++current_block);
 521                }
 522                set_buffer_uptodate(bh);
 523                unlock_buffer(bh);
 524                mark_buffer_dirty_inode(bh, inode);
 525                /* We used to sync bh here if IS_SYNC(inode).
 526                 * But we now rely upon generic_write_sync()
 527                 * and b_inode_buffers.  But not for directories.
 528                 */
 529                if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
 530                        sync_dirty_buffer(bh);
 531        }
 532        *blks = num;
 533        return err;
 534
 535failed:
 536        for (i = 1; i < n; i++)
 537                bforget(branch[i].bh);
 538        for (i = 0; i < indirect_blks; i++)
 539                ext2_free_blocks(inode, new_blocks[i], 1);
 540        ext2_free_blocks(inode, new_blocks[i], num);
 541        return err;
 542}
 543
 544/**
 545 * ext2_splice_branch - splice the allocated branch onto inode.
 546 * @inode: owner
 547 * @block: (logical) number of block we are adding
 548 * @where: location of missing link
 549 * @num:   number of indirect blocks we are adding
 550 * @blks:  number of direct blocks we are adding
 551 *
 552 * This function fills the missing link and does all housekeeping needed in
 553 * inode (->i_blocks, etc.). In case of success we end up with the full
 554 * chain to new block and return 0.
 555 */
 556static void ext2_splice_branch(struct inode *inode,
 557                        long block, Indirect *where, int num, int blks)
 558{
 559        int i;
 560        struct ext2_block_alloc_info *block_i;
 561        ext2_fsblk_t current_block;
 562
 563        block_i = EXT2_I(inode)->i_block_alloc_info;
 564
 565        /* XXX LOCKING probably should have i_meta_lock ?*/
 566        /* That's it */
 567
 568        *where->p = where->key;
 569
 570        /*
 571         * Update the host buffer_head or inode to point to more just allocated
 572         * direct blocks blocks
 573         */
 574        if (num == 0 && blks > 1) {
 575                current_block = le32_to_cpu(where->key) + 1;
 576                for (i = 1; i < blks; i++)
 577                        *(where->p + i ) = cpu_to_le32(current_block++);
 578        }
 579
 580        /*
 581         * update the most recently allocated logical & physical block
 582         * in i_block_alloc_info, to assist find the proper goal block for next
 583         * allocation
 584         */
 585        if (block_i) {
 586                block_i->last_alloc_logical_block = block + blks - 1;
 587                block_i->last_alloc_physical_block =
 588                                le32_to_cpu(where[num].key) + blks - 1;
 589        }
 590
 591        /* We are done with atomic stuff, now do the rest of housekeeping */
 592
 593        /* had we spliced it onto indirect block? */
 594        if (where->bh)
 595                mark_buffer_dirty_inode(where->bh, inode);
 596
 597        inode->i_ctime = CURRENT_TIME_SEC;
 598        mark_inode_dirty(inode);
 599}
 600
 601/*
 602 * Allocation strategy is simple: if we have to allocate something, we will
 603 * have to go the whole way to leaf. So let's do it before attaching anything
 604 * to tree, set linkage between the newborn blocks, write them if sync is
 605 * required, recheck the path, free and repeat if check fails, otherwise
 606 * set the last missing link (that will protect us from any truncate-generated
 607 * removals - all blocks on the path are immune now) and possibly force the
 608 * write on the parent block.
 609 * That has a nice additional property: no special recovery from the failed
 610 * allocations is needed - we simply release blocks and do not touch anything
 611 * reachable from inode.
 612 *
 613 * `handle' can be NULL if create == 0.
 614 *
 615 * return > 0, # of blocks mapped or allocated.
 616 * return = 0, if plain lookup failed.
 617 * return < 0, error case.
 618 */
 619static int ext2_get_blocks(struct inode *inode,
 620                           sector_t iblock, unsigned long maxblocks,
 621                           struct buffer_head *bh_result,
 622                           int create)
 623{
 624        int err = -EIO;
 625        int offsets[4];
 626        Indirect chain[4];
 627        Indirect *partial;
 628        ext2_fsblk_t goal;
 629        int indirect_blks;
 630        int blocks_to_boundary = 0;
 631        int depth;
 632        struct ext2_inode_info *ei = EXT2_I(inode);
 633        int count = 0;
 634        ext2_fsblk_t first_block = 0;
 635
 636        BUG_ON(maxblocks == 0);
 637
 638        depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 639
 640        if (depth == 0)
 641                return (err);
 642
 643        partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 644        /* Simplest case - block found, no allocation needed */
 645        if (!partial) {
 646                first_block = le32_to_cpu(chain[depth - 1].key);
 647                clear_buffer_new(bh_result); /* What's this do? */
 648                count++;
 649                /*map more blocks*/
 650                while (count < maxblocks && count <= blocks_to_boundary) {
 651                        ext2_fsblk_t blk;
 652
 653                        if (!verify_chain(chain, chain + depth - 1)) {
 654                                /*
 655                                 * Indirect block might be removed by
 656                                 * truncate while we were reading it.
 657                                 * Handling of that case: forget what we've
 658                                 * got now, go to reread.
 659                                 */
 660                                err = -EAGAIN;
 661                                count = 0;
 662                                break;
 663                        }
 664                        blk = le32_to_cpu(*(chain[depth-1].p + count));
 665                        if (blk == first_block + count)
 666                                count++;
 667                        else
 668                                break;
 669                }
 670                if (err != -EAGAIN)
 671                        goto got_it;
 672        }
 673
 674        /* Next simple case - plain lookup or failed read of indirect block */
 675        if (!create || err == -EIO)
 676                goto cleanup;
 677
 678        mutex_lock(&ei->truncate_mutex);
 679        /*
 680         * If the indirect block is missing while we are reading
 681         * the chain(ext2_get_branch() returns -EAGAIN err), or
 682         * if the chain has been changed after we grab the semaphore,
 683         * (either because another process truncated this branch, or
 684         * another get_block allocated this branch) re-grab the chain to see if
 685         * the request block has been allocated or not.
 686         *
 687         * Since we already block the truncate/other get_block
 688         * at this point, we will have the current copy of the chain when we
 689         * splice the branch into the tree.
 690         */
 691        if (err == -EAGAIN || !verify_chain(chain, partial)) {
 692                while (partial > chain) {
 693                        brelse(partial->bh);
 694                        partial--;
 695                }
 696                partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 697                if (!partial) {
 698                        count++;
 699                        mutex_unlock(&ei->truncate_mutex);
 700                        if (err)
 701                                goto cleanup;
 702                        clear_buffer_new(bh_result);
 703                        goto got_it;
 704                }
 705        }
 706
 707        /*
 708         * Okay, we need to do block allocation.  Lazily initialize the block
 709         * allocation info here if necessary
 710        */
 711        if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
 712                ext2_init_block_alloc_info(inode);
 713
 714        goal = ext2_find_goal(inode, iblock, partial);
 715
 716        /* the number of blocks need to allocate for [d,t]indirect blocks */
 717        indirect_blks = (chain + depth) - partial - 1;
 718        /*
 719         * Next look up the indirect map to count the totoal number of
 720         * direct blocks to allocate for this branch.
 721         */
 722        count = ext2_blks_to_allocate(partial, indirect_blks,
 723                                        maxblocks, blocks_to_boundary);
 724        /*
 725         * XXX ???? Block out ext2_truncate while we alter the tree
 726         */
 727        err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
 728                                offsets + (partial - chain), partial);
 729
 730        if (err) {
 731                mutex_unlock(&ei->truncate_mutex);
 732                goto cleanup;
 733        }
 734
 735        if (IS_DAX(inode)) {
 736                /*
 737                 * block must be initialised before we put it in the tree
 738                 * so that it's not found by another thread before it's
 739                 * initialised
 740                 */
 741                err = sb_issue_zeroout(inode->i_sb,
 742                                le32_to_cpu(chain[depth-1].key), count,
 743                                GFP_NOFS);
 744                if (err) {
 745                        mutex_unlock(&ei->truncate_mutex);
 746                        goto cleanup;
 747                }
 748        } else
 749                set_buffer_new(bh_result);
 750
 751        ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
 752        mutex_unlock(&ei->truncate_mutex);
 753got_it:
 754        map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
 755        if (count > blocks_to_boundary)
 756                set_buffer_boundary(bh_result);
 757        err = count;
 758        /* Clean up and exit */
 759        partial = chain + depth - 1;    /* the whole chain */
 760cleanup:
 761        while (partial > chain) {
 762                brelse(partial->bh);
 763                partial--;
 764        }
 765        return err;
 766}
 767
 768int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
 769{
 770        unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
 771        int ret = ext2_get_blocks(inode, iblock, max_blocks,
 772                              bh_result, create);
 773        if (ret > 0) {
 774                bh_result->b_size = (ret << inode->i_blkbits);
 775                ret = 0;
 776        }
 777        return ret;
 778
 779}
 780
 781int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 782                u64 start, u64 len)
 783{
 784        return generic_block_fiemap(inode, fieinfo, start, len,
 785                                    ext2_get_block);
 786}
 787
 788static int ext2_writepage(struct page *page, struct writeback_control *wbc)
 789{
 790        return block_write_full_page(page, ext2_get_block, wbc);
 791}
 792
 793static int ext2_readpage(struct file *file, struct page *page)
 794{
 795        return mpage_readpage(page, ext2_get_block);
 796}
 797
 798static int
 799ext2_readpages(struct file *file, struct address_space *mapping,
 800                struct list_head *pages, unsigned nr_pages)
 801{
 802        return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
 803}
 804
 805static int
 806ext2_write_begin(struct file *file, struct address_space *mapping,
 807                loff_t pos, unsigned len, unsigned flags,
 808                struct page **pagep, void **fsdata)
 809{
 810        int ret;
 811
 812        ret = block_write_begin(mapping, pos, len, flags, pagep,
 813                                ext2_get_block);
 814        if (ret < 0)
 815                ext2_write_failed(mapping, pos + len);
 816        return ret;
 817}
 818
 819static int ext2_write_end(struct file *file, struct address_space *mapping,
 820                        loff_t pos, unsigned len, unsigned copied,
 821                        struct page *page, void *fsdata)
 822{
 823        int ret;
 824
 825        ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 826        if (ret < len)
 827                ext2_write_failed(mapping, pos + len);
 828        return ret;
 829}
 830
 831static int
 832ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
 833                loff_t pos, unsigned len, unsigned flags,
 834                struct page **pagep, void **fsdata)
 835{
 836        int ret;
 837
 838        ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
 839                               ext2_get_block);
 840        if (ret < 0)
 841                ext2_write_failed(mapping, pos + len);
 842        return ret;
 843}
 844
 845static int ext2_nobh_writepage(struct page *page,
 846                        struct writeback_control *wbc)
 847{
 848        return nobh_writepage(page, ext2_get_block, wbc);
 849}
 850
 851static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 852{
 853        return generic_block_bmap(mapping,block,ext2_get_block);
 854}
 855
 856static ssize_t
 857ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 858{
 859        struct file *file = iocb->ki_filp;
 860        struct address_space *mapping = file->f_mapping;
 861        struct inode *inode = mapping->host;
 862        size_t count = iov_iter_count(iter);
 863        loff_t offset = iocb->ki_pos;
 864        ssize_t ret;
 865
 866        if (IS_DAX(inode))
 867                ret = dax_do_io(iocb, inode, iter, ext2_get_block, NULL,
 868                                DIO_LOCKING);
 869        else
 870                ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
 871        if (ret < 0 && iov_iter_rw(iter) == WRITE)
 872                ext2_write_failed(mapping, offset + count);
 873        return ret;
 874}
 875
 876static int
 877ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
 878{
 879#ifdef CONFIG_FS_DAX
 880        if (dax_mapping(mapping)) {
 881                return dax_writeback_mapping_range(mapping,
 882                                                   mapping->host->i_sb->s_bdev,
 883                                                   wbc);
 884        }
 885#endif
 886
 887        return mpage_writepages(mapping, wbc, ext2_get_block);
 888}
 889
 890const struct address_space_operations ext2_aops = {
 891        .readpage               = ext2_readpage,
 892        .readpages              = ext2_readpages,
 893        .writepage              = ext2_writepage,
 894        .write_begin            = ext2_write_begin,
 895        .write_end              = ext2_write_end,
 896        .bmap                   = ext2_bmap,
 897        .direct_IO              = ext2_direct_IO,
 898        .writepages             = ext2_writepages,
 899        .migratepage            = buffer_migrate_page,
 900        .is_partially_uptodate  = block_is_partially_uptodate,
 901        .error_remove_page      = generic_error_remove_page,
 902};
 903
 904const struct address_space_operations ext2_nobh_aops = {
 905        .readpage               = ext2_readpage,
 906        .readpages              = ext2_readpages,
 907        .writepage              = ext2_nobh_writepage,
 908        .write_begin            = ext2_nobh_write_begin,
 909        .write_end              = nobh_write_end,
 910        .bmap                   = ext2_bmap,
 911        .direct_IO              = ext2_direct_IO,
 912        .writepages             = ext2_writepages,
 913        .migratepage            = buffer_migrate_page,
 914        .error_remove_page      = generic_error_remove_page,
 915};
 916
 917/*
 918 * Probably it should be a library function... search for first non-zero word
 919 * or memcmp with zero_page, whatever is better for particular architecture.
 920 * Linus?
 921 */
 922static inline int all_zeroes(__le32 *p, __le32 *q)
 923{
 924        while (p < q)
 925                if (*p++)
 926                        return 0;
 927        return 1;
 928}
 929
 930/**
 931 *      ext2_find_shared - find the indirect blocks for partial truncation.
 932 *      @inode:   inode in question
 933 *      @depth:   depth of the affected branch
 934 *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
 935 *      @chain:   place to store the pointers to partial indirect blocks
 936 *      @top:     place to the (detached) top of branch
 937 *
 938 *      This is a helper function used by ext2_truncate().
 939 *
 940 *      When we do truncate() we may have to clean the ends of several indirect
 941 *      blocks but leave the blocks themselves alive. Block is partially
 942 *      truncated if some data below the new i_size is referred from it (and
 943 *      it is on the path to the first completely truncated data block, indeed).
 944 *      We have to free the top of that path along with everything to the right
 945 *      of the path. Since no allocation past the truncation point is possible
 946 *      until ext2_truncate() finishes, we may safely do the latter, but top
 947 *      of branch may require special attention - pageout below the truncation
 948 *      point might try to populate it.
 949 *
 950 *      We atomically detach the top of branch from the tree, store the block
 951 *      number of its root in *@top, pointers to buffer_heads of partially
 952 *      truncated blocks - in @chain[].bh and pointers to their last elements
 953 *      that should not be removed - in @chain[].p. Return value is the pointer
 954 *      to last filled element of @chain.
 955 *
 956 *      The work left to caller to do the actual freeing of subtrees:
 957 *              a) free the subtree starting from *@top
 958 *              b) free the subtrees whose roots are stored in
 959 *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
 960 *              c) free the subtrees growing from the inode past the @chain[0].p
 961 *                      (no partially truncated stuff there).
 962 */
 963
 964static Indirect *ext2_find_shared(struct inode *inode,
 965                                int depth,
 966                                int offsets[4],
 967                                Indirect chain[4],
 968                                __le32 *top)
 969{
 970        Indirect *partial, *p;
 971        int k, err;
 972
 973        *top = 0;
 974        for (k = depth; k > 1 && !offsets[k-1]; k--)
 975                ;
 976        partial = ext2_get_branch(inode, k, offsets, chain, &err);
 977        if (!partial)
 978                partial = chain + k-1;
 979        /*
 980         * If the branch acquired continuation since we've looked at it -
 981         * fine, it should all survive and (new) top doesn't belong to us.
 982         */
 983        write_lock(&EXT2_I(inode)->i_meta_lock);
 984        if (!partial->key && *partial->p) {
 985                write_unlock(&EXT2_I(inode)->i_meta_lock);
 986                goto no_top;
 987        }
 988        for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
 989                ;
 990        /*
 991         * OK, we've found the last block that must survive. The rest of our
 992         * branch should be detached before unlocking. However, if that rest
 993         * of branch is all ours and does not grow immediately from the inode
 994         * it's easier to cheat and just decrement partial->p.
 995         */
 996        if (p == chain + k - 1 && p > chain) {
 997                p->p--;
 998        } else {
 999                *top = *p->p;
1000                *p->p = 0;
1001        }
1002        write_unlock(&EXT2_I(inode)->i_meta_lock);
1003
1004        while(partial > p)
1005        {
1006                brelse(partial->bh);
1007                partial--;
1008        }
1009no_top:
1010        return partial;
1011}
1012
1013/**
1014 *      ext2_free_data - free a list of data blocks
1015 *      @inode: inode we are dealing with
1016 *      @p:     array of block numbers
1017 *      @q:     points immediately past the end of array
1018 *
1019 *      We are freeing all blocks referred from that array (numbers are
1020 *      stored as little-endian 32-bit) and updating @inode->i_blocks
1021 *      appropriately.
1022 */
1023static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1024{
1025        unsigned long block_to_free = 0, count = 0;
1026        unsigned long nr;
1027
1028        for ( ; p < q ; p++) {
1029                nr = le32_to_cpu(*p);
1030                if (nr) {
1031                        *p = 0;
1032                        /* accumulate blocks to free if they're contiguous */
1033                        if (count == 0)
1034                                goto free_this;
1035                        else if (block_to_free == nr - count)
1036                                count++;
1037                        else {
1038                                ext2_free_blocks (inode, block_to_free, count);
1039                                mark_inode_dirty(inode);
1040                        free_this:
1041                                block_to_free = nr;
1042                                count = 1;
1043                        }
1044                }
1045        }
1046        if (count > 0) {
1047                ext2_free_blocks (inode, block_to_free, count);
1048                mark_inode_dirty(inode);
1049        }
1050}
1051
1052/**
1053 *      ext2_free_branches - free an array of branches
1054 *      @inode: inode we are dealing with
1055 *      @p:     array of block numbers
1056 *      @q:     pointer immediately past the end of array
1057 *      @depth: depth of the branches to free
1058 *
1059 *      We are freeing all blocks referred from these branches (numbers are
1060 *      stored as little-endian 32-bit) and updating @inode->i_blocks
1061 *      appropriately.
1062 */
1063static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1064{
1065        struct buffer_head * bh;
1066        unsigned long nr;
1067
1068        if (depth--) {
1069                int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1070                for ( ; p < q ; p++) {
1071                        nr = le32_to_cpu(*p);
1072                        if (!nr)
1073                                continue;
1074                        *p = 0;
1075                        bh = sb_bread(inode->i_sb, nr);
1076                        /*
1077                         * A read failure? Report error and clear slot
1078                         * (should be rare).
1079                         */ 
1080                        if (!bh) {
1081                                ext2_error(inode->i_sb, "ext2_free_branches",
1082                                        "Read failure, inode=%ld, block=%ld",
1083                                        inode->i_ino, nr);
1084                                continue;
1085                        }
1086                        ext2_free_branches(inode,
1087                                           (__le32*)bh->b_data,
1088                                           (__le32*)bh->b_data + addr_per_block,
1089                                           depth);
1090                        bforget(bh);
1091                        ext2_free_blocks(inode, nr, 1);
1092                        mark_inode_dirty(inode);
1093                }
1094        } else
1095                ext2_free_data(inode, p, q);
1096}
1097
1098/* dax_sem must be held when calling this function */
1099static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1100{
1101        __le32 *i_data = EXT2_I(inode)->i_data;
1102        struct ext2_inode_info *ei = EXT2_I(inode);
1103        int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1104        int offsets[4];
1105        Indirect chain[4];
1106        Indirect *partial;
1107        __le32 nr = 0;
1108        int n;
1109        long iblock;
1110        unsigned blocksize;
1111        blocksize = inode->i_sb->s_blocksize;
1112        iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1113
1114#ifdef CONFIG_FS_DAX
1115        WARN_ON(!rwsem_is_locked(&ei->dax_sem));
1116#endif
1117
1118        n = ext2_block_to_path(inode, iblock, offsets, NULL);
1119        if (n == 0)
1120                return;
1121
1122        /*
1123         * From here we block out all ext2_get_block() callers who want to
1124         * modify the block allocation tree.
1125         */
1126        mutex_lock(&ei->truncate_mutex);
1127
1128        if (n == 1) {
1129                ext2_free_data(inode, i_data+offsets[0],
1130                                        i_data + EXT2_NDIR_BLOCKS);
1131                goto do_indirects;
1132        }
1133
1134        partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1135        /* Kill the top of shared branch (already detached) */
1136        if (nr) {
1137                if (partial == chain)
1138                        mark_inode_dirty(inode);
1139                else
1140                        mark_buffer_dirty_inode(partial->bh, inode);
1141                ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1142        }
1143        /* Clear the ends of indirect blocks on the shared branch */
1144        while (partial > chain) {
1145                ext2_free_branches(inode,
1146                                   partial->p + 1,
1147                                   (__le32*)partial->bh->b_data+addr_per_block,
1148                                   (chain+n-1) - partial);
1149                mark_buffer_dirty_inode(partial->bh, inode);
1150                brelse (partial->bh);
1151                partial--;
1152        }
1153do_indirects:
1154        /* Kill the remaining (whole) subtrees */
1155        switch (offsets[0]) {
1156                default:
1157                        nr = i_data[EXT2_IND_BLOCK];
1158                        if (nr) {
1159                                i_data[EXT2_IND_BLOCK] = 0;
1160                                mark_inode_dirty(inode);
1161                                ext2_free_branches(inode, &nr, &nr+1, 1);
1162                        }
1163                case EXT2_IND_BLOCK:
1164                        nr = i_data[EXT2_DIND_BLOCK];
1165                        if (nr) {
1166                                i_data[EXT2_DIND_BLOCK] = 0;
1167                                mark_inode_dirty(inode);
1168                                ext2_free_branches(inode, &nr, &nr+1, 2);
1169                        }
1170                case EXT2_DIND_BLOCK:
1171                        nr = i_data[EXT2_TIND_BLOCK];
1172                        if (nr) {
1173                                i_data[EXT2_TIND_BLOCK] = 0;
1174                                mark_inode_dirty(inode);
1175                                ext2_free_branches(inode, &nr, &nr+1, 3);
1176                        }
1177                case EXT2_TIND_BLOCK:
1178                        ;
1179        }
1180
1181        ext2_discard_reservation(inode);
1182
1183        mutex_unlock(&ei->truncate_mutex);
1184}
1185
1186static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1187{
1188        /*
1189         * XXX: it seems like a bug here that we don't allow
1190         * IS_APPEND inode to have blocks-past-i_size trimmed off.
1191         * review and fix this.
1192         *
1193         * Also would be nice to be able to handle IO errors and such,
1194         * but that's probably too much to ask.
1195         */
1196        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1197            S_ISLNK(inode->i_mode)))
1198                return;
1199        if (ext2_inode_is_fast_symlink(inode))
1200                return;
1201        if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1202                return;
1203
1204        dax_sem_down_write(EXT2_I(inode));
1205        __ext2_truncate_blocks(inode, offset);
1206        dax_sem_up_write(EXT2_I(inode));
1207}
1208
1209static int ext2_setsize(struct inode *inode, loff_t newsize)
1210{
1211        int error;
1212
1213        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1214            S_ISLNK(inode->i_mode)))
1215                return -EINVAL;
1216        if (ext2_inode_is_fast_symlink(inode))
1217                return -EINVAL;
1218        if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1219                return -EPERM;
1220
1221        inode_dio_wait(inode);
1222
1223        if (IS_DAX(inode))
1224                error = dax_truncate_page(inode, newsize, ext2_get_block);
1225        else if (test_opt(inode->i_sb, NOBH))
1226                error = nobh_truncate_page(inode->i_mapping,
1227                                newsize, ext2_get_block);
1228        else
1229                error = block_truncate_page(inode->i_mapping,
1230                                newsize, ext2_get_block);
1231        if (error)
1232                return error;
1233
1234        dax_sem_down_write(EXT2_I(inode));
1235        truncate_setsize(inode, newsize);
1236        __ext2_truncate_blocks(inode, newsize);
1237        dax_sem_up_write(EXT2_I(inode));
1238
1239        inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1240        if (inode_needs_sync(inode)) {
1241                sync_mapping_buffers(inode->i_mapping);
1242                sync_inode_metadata(inode, 1);
1243        } else {
1244                mark_inode_dirty(inode);
1245        }
1246
1247        return 0;
1248}
1249
1250static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1251                                        struct buffer_head **p)
1252{
1253        struct buffer_head * bh;
1254        unsigned long block_group;
1255        unsigned long block;
1256        unsigned long offset;
1257        struct ext2_group_desc * gdp;
1258
1259        *p = NULL;
1260        if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1261            ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1262                goto Einval;
1263
1264        block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1265        gdp = ext2_get_group_desc(sb, block_group, NULL);
1266        if (!gdp)
1267                goto Egdp;
1268        /*
1269         * Figure out the offset within the block group inode table
1270         */
1271        offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1272        block = le32_to_cpu(gdp->bg_inode_table) +
1273                (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1274        if (!(bh = sb_bread(sb, block)))
1275                goto Eio;
1276
1277        *p = bh;
1278        offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1279        return (struct ext2_inode *) (bh->b_data + offset);
1280
1281Einval:
1282        ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1283                   (unsigned long) ino);
1284        return ERR_PTR(-EINVAL);
1285Eio:
1286        ext2_error(sb, "ext2_get_inode",
1287                   "unable to read inode block - inode=%lu, block=%lu",
1288                   (unsigned long) ino, block);
1289Egdp:
1290        return ERR_PTR(-EIO);
1291}
1292
1293void ext2_set_inode_flags(struct inode *inode)
1294{
1295        unsigned int flags = EXT2_I(inode)->i_flags;
1296
1297        inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1298                                S_DIRSYNC | S_DAX);
1299        if (flags & EXT2_SYNC_FL)
1300                inode->i_flags |= S_SYNC;
1301        if (flags & EXT2_APPEND_FL)
1302                inode->i_flags |= S_APPEND;
1303        if (flags & EXT2_IMMUTABLE_FL)
1304                inode->i_flags |= S_IMMUTABLE;
1305        if (flags & EXT2_NOATIME_FL)
1306                inode->i_flags |= S_NOATIME;
1307        if (flags & EXT2_DIRSYNC_FL)
1308                inode->i_flags |= S_DIRSYNC;
1309        if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1310                inode->i_flags |= S_DAX;
1311}
1312
1313/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1314void ext2_get_inode_flags(struct ext2_inode_info *ei)
1315{
1316        unsigned int flags = ei->vfs_inode.i_flags;
1317
1318        ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1319                        EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1320        if (flags & S_SYNC)
1321                ei->i_flags |= EXT2_SYNC_FL;
1322        if (flags & S_APPEND)
1323                ei->i_flags |= EXT2_APPEND_FL;
1324        if (flags & S_IMMUTABLE)
1325                ei->i_flags |= EXT2_IMMUTABLE_FL;
1326        if (flags & S_NOATIME)
1327                ei->i_flags |= EXT2_NOATIME_FL;
1328        if (flags & S_DIRSYNC)
1329                ei->i_flags |= EXT2_DIRSYNC_FL;
1330}
1331
1332struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1333{
1334        struct ext2_inode_info *ei;
1335        struct buffer_head * bh;
1336        struct ext2_inode *raw_inode;
1337        struct inode *inode;
1338        long ret = -EIO;
1339        int n;
1340        uid_t i_uid;
1341        gid_t i_gid;
1342
1343        inode = iget_locked(sb, ino);
1344        if (!inode)
1345                return ERR_PTR(-ENOMEM);
1346        if (!(inode->i_state & I_NEW))
1347                return inode;
1348
1349        ei = EXT2_I(inode);
1350        ei->i_block_alloc_info = NULL;
1351
1352        raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1353        if (IS_ERR(raw_inode)) {
1354                ret = PTR_ERR(raw_inode);
1355                goto bad_inode;
1356        }
1357
1358        inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1359        i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1360        i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1361        if (!(test_opt (inode->i_sb, NO_UID32))) {
1362                i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1363                i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1364        }
1365        i_uid_write(inode, i_uid);
1366        i_gid_write(inode, i_gid);
1367        set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1368        inode->i_size = le32_to_cpu(raw_inode->i_size);
1369        inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1370        inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1371        inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1372        inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1373        ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1374        /* We now have enough fields to check if the inode was active or not.
1375         * This is needed because nfsd might try to access dead inodes
1376         * the test is that same one that e2fsck uses
1377         * NeilBrown 1999oct15
1378         */
1379        if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1380                /* this inode is deleted */
1381                brelse (bh);
1382                ret = -ESTALE;
1383                goto bad_inode;
1384        }
1385        inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1386        ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1387        ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1388        ei->i_frag_no = raw_inode->i_frag;
1389        ei->i_frag_size = raw_inode->i_fsize;
1390        ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1391        ei->i_dir_acl = 0;
1392        if (S_ISREG(inode->i_mode))
1393                inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1394        else
1395                ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1396        ei->i_dtime = 0;
1397        inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1398        ei->i_state = 0;
1399        ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1400        ei->i_dir_start_lookup = 0;
1401
1402        /*
1403         * NOTE! The in-memory inode i_data array is in little-endian order
1404         * even on big-endian machines: we do NOT byteswap the block numbers!
1405         */
1406        for (n = 0; n < EXT2_N_BLOCKS; n++)
1407                ei->i_data[n] = raw_inode->i_block[n];
1408
1409        if (S_ISREG(inode->i_mode)) {
1410                inode->i_op = &ext2_file_inode_operations;
1411                if (test_opt(inode->i_sb, NOBH)) {
1412                        inode->i_mapping->a_ops = &ext2_nobh_aops;
1413                        inode->i_fop = &ext2_file_operations;
1414                } else {
1415                        inode->i_mapping->a_ops = &ext2_aops;
1416                        inode->i_fop = &ext2_file_operations;
1417                }
1418        } else if (S_ISDIR(inode->i_mode)) {
1419                inode->i_op = &ext2_dir_inode_operations;
1420                inode->i_fop = &ext2_dir_operations;
1421                if (test_opt(inode->i_sb, NOBH))
1422                        inode->i_mapping->a_ops = &ext2_nobh_aops;
1423                else
1424                        inode->i_mapping->a_ops = &ext2_aops;
1425        } else if (S_ISLNK(inode->i_mode)) {
1426                if (ext2_inode_is_fast_symlink(inode)) {
1427                        inode->i_link = (char *)ei->i_data;
1428                        inode->i_op = &ext2_fast_symlink_inode_operations;
1429                        nd_terminate_link(ei->i_data, inode->i_size,
1430                                sizeof(ei->i_data) - 1);
1431                } else {
1432                        inode->i_op = &ext2_symlink_inode_operations;
1433                        inode_nohighmem(inode);
1434                        if (test_opt(inode->i_sb, NOBH))
1435                                inode->i_mapping->a_ops = &ext2_nobh_aops;
1436                        else
1437                                inode->i_mapping->a_ops = &ext2_aops;
1438                }
1439        } else {
1440                inode->i_op = &ext2_special_inode_operations;
1441                if (raw_inode->i_block[0])
1442                        init_special_inode(inode, inode->i_mode,
1443                           old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1444                else 
1445                        init_special_inode(inode, inode->i_mode,
1446                           new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1447        }
1448        brelse (bh);
1449        ext2_set_inode_flags(inode);
1450        unlock_new_inode(inode);
1451        return inode;
1452        
1453bad_inode:
1454        iget_failed(inode);
1455        return ERR_PTR(ret);
1456}
1457
1458static int __ext2_write_inode(struct inode *inode, int do_sync)
1459{
1460        struct ext2_inode_info *ei = EXT2_I(inode);
1461        struct super_block *sb = inode->i_sb;
1462        ino_t ino = inode->i_ino;
1463        uid_t uid = i_uid_read(inode);
1464        gid_t gid = i_gid_read(inode);
1465        struct buffer_head * bh;
1466        struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1467        int n;
1468        int err = 0;
1469
1470        if (IS_ERR(raw_inode))
1471                return -EIO;
1472
1473        /* For fields not not tracking in the in-memory inode,
1474         * initialise them to zero for new inodes. */
1475        if (ei->i_state & EXT2_STATE_NEW)
1476                memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1477
1478        ext2_get_inode_flags(ei);
1479        raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1480        if (!(test_opt(sb, NO_UID32))) {
1481                raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1482                raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1483/*
1484 * Fix up interoperability with old kernels. Otherwise, old inodes get
1485 * re-used with the upper 16 bits of the uid/gid intact
1486 */
1487                if (!ei->i_dtime) {
1488                        raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1489                        raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1490                } else {
1491                        raw_inode->i_uid_high = 0;
1492                        raw_inode->i_gid_high = 0;
1493                }
1494        } else {
1495                raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1496                raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1497                raw_inode->i_uid_high = 0;
1498                raw_inode->i_gid_high = 0;
1499        }
1500        raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1501        raw_inode->i_size = cpu_to_le32(inode->i_size);
1502        raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1503        raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1504        raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1505
1506        raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1507        raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1508        raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1509        raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1510        raw_inode->i_frag = ei->i_frag_no;
1511        raw_inode->i_fsize = ei->i_frag_size;
1512        raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1513        if (!S_ISREG(inode->i_mode))
1514                raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1515        else {
1516                raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1517                if (inode->i_size > 0x7fffffffULL) {
1518                        if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1519                                        EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1520                            EXT2_SB(sb)->s_es->s_rev_level ==
1521                                        cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1522                               /* If this is the first large file
1523                                * created, add a flag to the superblock.
1524                                */
1525                                spin_lock(&EXT2_SB(sb)->s_lock);
1526                                ext2_update_dynamic_rev(sb);
1527                                EXT2_SET_RO_COMPAT_FEATURE(sb,
1528                                        EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1529                                spin_unlock(&EXT2_SB(sb)->s_lock);
1530                                ext2_write_super(sb);
1531                        }
1532                }
1533        }
1534        
1535        raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1536        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1537                if (old_valid_dev(inode->i_rdev)) {
1538                        raw_inode->i_block[0] =
1539                                cpu_to_le32(old_encode_dev(inode->i_rdev));
1540                        raw_inode->i_block[1] = 0;
1541                } else {
1542                        raw_inode->i_block[0] = 0;
1543                        raw_inode->i_block[1] =
1544                                cpu_to_le32(new_encode_dev(inode->i_rdev));
1545                        raw_inode->i_block[2] = 0;
1546                }
1547        } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1548                raw_inode->i_block[n] = ei->i_data[n];
1549        mark_buffer_dirty(bh);
1550        if (do_sync) {
1551                sync_dirty_buffer(bh);
1552                if (buffer_req(bh) && !buffer_uptodate(bh)) {
1553                        printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1554                                sb->s_id, (unsigned long) ino);
1555                        err = -EIO;
1556                }
1557        }
1558        ei->i_state &= ~EXT2_STATE_NEW;
1559        brelse (bh);
1560        return err;
1561}
1562
1563int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1564{
1565        return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1566}
1567
1568int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1569{
1570        struct inode *inode = d_inode(dentry);
1571        int error;
1572
1573        error = inode_change_ok(inode, iattr);
1574        if (error)
1575                return error;
1576
1577        if (is_quota_modification(inode, iattr)) {
1578                error = dquot_initialize(inode);
1579                if (error)
1580                        return error;
1581        }
1582        if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1583            (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1584                error = dquot_transfer(inode, iattr);
1585                if (error)
1586                        return error;
1587        }
1588        if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1589                error = ext2_setsize(inode, iattr->ia_size);
1590                if (error)
1591                        return error;
1592        }
1593        setattr_copy(inode, iattr);
1594        if (iattr->ia_valid & ATTR_MODE)
1595                error = posix_acl_chmod(inode, inode->i_mode);
1596        mark_inode_dirty(inode);
1597
1598        return error;
1599}
1600