fs/ext2/inode.c

   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/smp_lock.h>
  26 #include <linux/time.h>
  27 #include <linux/highuid.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/quotaops.h>
  30 #include <linux/module.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 "ext2.h"
  37 #include "acl.h"
  38 #include "xip.h"
  39
  40 MODULE_AUTHOR("Remy Card and others");
  41 MODULE_DESCRIPTION("Second Extended Filesystem");
  42 MODULE_LICENSE("GPL");
  43
  44 static int ext2_update_inode(struct inode * inode, int do_sync);
  45
  46 /*
  47  * Test whether an inode is a fast symlink.
  48  */
  49 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
  50 {
  51         int ea_blocks = EXT2_I(inode)->i_file_acl ?
  52                 (inode->i_sb->s_blocksize >> 9) : 0;
  53
  54         return (S_ISLNK(inode->i_mode) &&
  55                 inode->i_blocks - ea_blocks == 0);
  56 }
  57
  58 /*
  59  * Called at the last iput() if i_nlink is zero.
  60  */
  61 void ext2_delete_inode (struct inode * inode)
  62 {
  63         truncate_inode_pages(&inode->i_data, 0);
  64
  65         if (is_bad_inode(inode))
  66                 goto no_delete;
  67         EXT2_I(inode)->i_dtime  = get_seconds();
  68         mark_inode_dirty(inode);
  69         ext2_update_inode(inode, inode_needs_sync(inode));
  70
  71         inode->i_size = 0;
  72         if (inode->i_blocks)
  73                 ext2_truncate (inode);
  74         ext2_free_inode (inode);
  75
  76         return;
  77 no_delete:
  78         clear_inode(inode);     /* We must guarantee clearing of inode... */
  79 }
  80
  81 typedef struct {
  82         __le32  *p;
  83         __le32  key;
  84         struct buffer_head *bh;
  85 } Indirect;
  86
  87 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
  88 {
  89         p->key = *(p->p = v);
  90         p->bh = bh;
  91 }
  92
  93 static inline int verify_chain(Indirect *from, Indirect *to)
  94 {
  95         while (from <= to && from->key == *from->p)
  96                 from++;
  97         return (from > to);
  98 }
  99
 100 /**
 101  *      ext2_block_to_path - parse the block number into array of offsets
 102  *      @inode: inode in question (we are only interested in its superblock)
 103  *      @i_block: block number to be parsed
 104  *      @offsets: array to store the offsets in
 105  *      @boundary: set this non-zero if the referred-to block is likely to be
 106  *             followed (on disk) by an indirect block.
 107  *      To store the locations of file's data ext2 uses a data structure common
 108  *      for UNIX filesystems - tree of pointers anchored in the inode, with
 109  *      data blocks at leaves and indirect blocks in intermediate nodes.
 110  *      This function translates the block number into path in that tree -
 111  *      return value is the path length and @offsets[n] is the offset of
 112  *      pointer to (n+1)th node in the nth one. If @block is out of range
 113  *      (negative or too large) warning is printed and zero returned.
 114  *
 115  *      Note: function doesn't find node addresses, so no IO is needed. All
 116  *      we need to know is the capacity of indirect blocks (taken from the
 117  *      inode->i_sb).
 118  */
 119
 120 /*
 121  * Portability note: the last comparison (check that we fit into triple
 122  * indirect block) is spelled differently, because otherwise on an
 123  * architecture with 32-bit longs and 8Kb pages we might get into trouble
 124  * if our filesystem had 8Kb blocks. We might use long long, but that would
 125  * kill us on x86. Oh, well, at least the sign propagation does not matter -
 126  * i_block would have to be negative in the very beginning, so we would not
 127  * get there at all.
 128  */
 129
 130 static int ext2_block_to_path(struct inode *inode,
 131                         long i_block, int offsets[4], int *boundary)
 132 {
 133         int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
 134         int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
 135         const long direct_blocks = EXT2_NDIR_BLOCKS,
 136                 indirect_blocks = ptrs,
 137                 double_blocks = (1 << (ptrs_bits * 2));
 138         int n = 0;
 139         int final = 0;
 140
 141         if (i_block < 0) {
 142                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
 143         } else if (i_block < direct_blocks) {
 144                 offsets[n++] = i_block;
 145                 final = direct_blocks;
 146         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
 147                 offsets[n++] = EXT2_IND_BLOCK;
 148                 offsets[n++] = i_block;
 149                 final = ptrs;
 150         } else if ((i_block -= indirect_blocks) < double_blocks) {
 151                 offsets[n++] = EXT2_DIND_BLOCK;
 152                 offsets[n++] = i_block >> ptrs_bits;
 153                 offsets[n++] = i_block & (ptrs - 1);
 154                 final = ptrs;
 155         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
 156                 offsets[n++] = EXT2_TIND_BLOCK;
 157                 offsets[n++] = i_block >> (ptrs_bits * 2);
 158                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
 159                 offsets[n++] = i_block & (ptrs - 1);
 160                 final = ptrs;
 161         } else {
 162                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
 163         }
 164         if (boundary)
 165                 *boundary = final - 1 - (i_block & (ptrs - 1));
 166
 167         return n;
 168 }
 169
 170 /**
 171  *      ext2_get_branch - read the chain of indirect blocks leading to data
 172  *      @inode: inode in question
 173  *      @depth: depth of the chain (1 - direct pointer, etc.)
 174  *      @offsets: offsets of pointers in inode/indirect blocks
 175  *      @chain: place to store the result
 176  *      @err: here we store the error value
 177  *
 178  *      Function fills the array of triples <key, p, bh> and returns %NULL
 179  *      if everything went OK or the pointer to the last filled triple
 180  *      (incomplete one) otherwise. Upon the return chain[i].key contains
 181  *      the number of (i+1)-th block in the chain (as it is stored in memory,
 182  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
 183  *      number (it points into struct inode for i==0 and into the bh->b_data
 184  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 185  *      block for i>0 and NULL for i==0. In other words, it holds the block
 186  *      numbers of the chain, addresses they were taken from (and where we can
 187  *      verify that chain did not change) and buffer_heads hosting these
 188  *      numbers.
 189  *
 190  *      Function stops when it stumbles upon zero pointer (absent block)
 191  *              (pointer to last triple returned, *@err == 0)
 192  *      or when it gets an IO error reading an indirect block
 193  *              (ditto, *@err == -EIO)
 194  *      or when it notices that chain had been changed while it was reading
 195  *              (ditto, *@err == -EAGAIN)
 196  *      or when it reads all @depth-1 indirect blocks successfully and finds
 197  *      the whole chain, all way to the data (returns %NULL, *err == 0).
 198  */
 199 static Indirect *ext2_get_branch(struct inode *inode,
 200                                  int depth,
 201                                  int *offsets,
 202                                  Indirect chain[4],
 203                                  int *err)
 204 {
 205         struct super_block *sb = inode->i_sb;
 206         Indirect *p = chain;
 207         struct buffer_head *bh;
 208
 209         *err = 0;
 210         /* i_data is not going away, no lock needed */
 211         add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
 212         if (!p->key)
 213                 goto no_block;
 214         while (--depth) {
 215                 bh = sb_bread(sb, le32_to_cpu(p->key));
 216                 if (!bh)
 217                         goto failure;
 218                 read_lock(&EXT2_I(inode)->i_meta_lock);
 219                 if (!verify_chain(chain, p))
 220                         goto changed;
 221                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
 222                 read_unlock(&EXT2_I(inode)->i_meta_lock);
 223                 if (!p->key)
 224                         goto no_block;
 225         }
 226         return NULL;
 227
 228 changed:
 229         read_unlock(&EXT2_I(inode)->i_meta_lock);
 230         brelse(bh);
 231         *err = -EAGAIN;
 232         goto no_block;
 233 failure:
 234         *err = -EIO;
 235 no_block:
 236         return p;
 237 }
 238
 239 /**
 240  *      ext2_find_near - find a place for allocation with sufficient locality
 241  *      @inode: owner
 242  *      @ind: descriptor of indirect block.
 243  *
 244  *      This function returns the preferred place for block allocation.
 245  *      It is used when heuristic for sequential allocation fails.
 246  *      Rules are:
 247  *        + if there is a block to the left of our position - allocate near it.
 248  *        + if pointer will live in indirect block - allocate near that block.
 249  *        + if pointer will live in inode - allocate in the same cylinder group.
 250  *
 251  * In the latter case we colour the starting block by the callers PID to
 252  * prevent it from clashing with concurrent allocations for a different inode
 253  * in the same block group.   The PID is used here so that functionally related
 254  * files will be close-by on-disk.
 255  *
 256  *      Caller must make sure that @ind is valid and will stay that way.
 257  */
 258
 259 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
 260 {
 261         struct ext2_inode_info *ei = EXT2_I(inode);
 262         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
 263         __le32 *p;
 264         ext2_fsblk_t bg_start;
 265         ext2_fsblk_t colour;
 266
 267         /* Try to find previous block */
 268         for (p = ind->p - 1; p >= start; p--)
 269                 if (*p)
 270                         return le32_to_cpu(*p);
 271
 272         /* No such thing, so let's try location of indirect block */
 273         if (ind->bh)
 274                 return ind->bh->b_blocknr;
 275
 276         /*
 277          * It is going to be refered from inode itself? OK, just put it into
 278          * the same cylinder group then.
 279          */
 280         bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
 281         colour = (current->pid % 16) *
 282                         (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 283         return bg_start + colour;
 284 }
 285
 286 /**
 287  *      ext2_find_goal - find a preferred place for allocation.
 288  *      @inode: owner
 289  *      @block:  block we want
 290  *      @partial: pointer to the last triple within a chain
 291  *
 292  *      Returns preferred place for a block (the goal).
 293  */
 294
 295 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
 296                                           Indirect *partial)
 297 {
 298         struct ext2_block_alloc_info *block_i;
 299
 300         block_i = EXT2_I(inode)->i_block_alloc_info;
 301
 302         /*
 303          * try the heuristic for sequential allocation,
 304          * failing that at least try to get decent locality.
 305          */
 306         if (block_i && (block == block_i->last_alloc_logical_block + 1)
 307                 && (block_i->last_alloc_physical_block != 0)) {
 308                 return block_i->last_alloc_physical_block + 1;
 309         }
 310
 311         return ext2_find_near(inode, partial);
 312 }
 313
 314 /**
 315  *      ext2_blks_to_allocate: Look up the block map and count the number
 316  *      of direct blocks need to be allocated for the given branch.
 317  *
 318  *      @branch: chain of indirect blocks
 319  *      @k: number of blocks need for indirect blocks
 320  *      @blks: number of data blocks to be mapped.
 321  *      @blocks_to_boundary:  the offset in the indirect block
 322  *
 323  *      return the total number of blocks to be allocate, including the
 324  *      direct and indirect blocks.
 325  */
 326 static int
 327 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
 328                 int blocks_to_boundary)
 329 {
 330         unsigned long count = 0;
 331
 332         /*
 333          * Simple case, [t,d]Indirect block(s) has not allocated yet
 334          * then it's clear blocks on that path have not allocated
 335          */
 336         if (k > 0) {
 337                 /* right now don't hanel cross boundary allocation */
 338                 if (blks < blocks_to_boundary + 1)
 339                         count += blks;
 340                 else
 341                         count += blocks_to_boundary + 1;
 342                 return count;
 343         }
 344
 345         count++;
 346         while (count < blks && count <= blocks_to_boundary
 347                 && le32_to_cpu(*(branch[0].p + count)) == 0) {
 348                 count++;
 349         }
 350         return count;
 351 }
 352
 353 /**
 354  *      ext2_alloc_blocks: multiple allocate blocks needed for a branch
 355  *      @indirect_blks: the number of blocks need to allocate for indirect
 356  *                      blocks
 357  *
 358  *      @new_blocks: on return it will store the new block numbers for
 359  *      the indirect blocks(if needed) and the first direct block,
 360  *      @blks:  on return it will store the total number of allocated
 361  *              direct blocks
 362  */
 363 static int ext2_alloc_blocks(struct inode *inode,
 364                         ext2_fsblk_t goal, int indirect_blks, int blks,
 365                         ext2_fsblk_t new_blocks[4], int *err)
 366 {
 367         int target, i;
 368         unsigned long count = 0;
 369         int index = 0;
 370         ext2_fsblk_t current_block = 0;
 371         int ret = 0;
 372
 373         /*
 374          * Here we try to allocate the requested multiple blocks at once,
 375          * on a best-effort basis.
 376          * To build a branch, we should allocate blocks for
 377          * the indirect blocks(if not allocated yet), and at least
 378          * the first direct block of this branch.  That's the
 379          * minimum number of blocks need to allocate(required)
 380          */
 381         target = blks + indirect_blks;
 382
 383         while (1) {
 384                 count = target;
 385                 /* allocating blocks for indirect blocks and direct blocks */
 386                 current_block = ext2_new_blocks(inode,goal,&count,err);
 387                 if (*err)
 388                         goto failed_out;
 389
 390                 target -= count;
 391                 /* allocate blocks for indirect blocks */
 392                 while (index < indirect_blks && count) {
 393                         new_blocks[index++] = current_block++;
 394                         count--;
 395                 }
 396
 397                 if (count > 0)
 398                         break;
 399         }
 400
 401         /* save the new block number for the first direct block */
 402         new_blocks[index] = current_block;
 403
 404         /* total number of blocks allocated for direct blocks */
 405         ret = count;
 406         *err = 0;
 407         return ret;
 408 failed_out:
 409         for (i = 0; i <index; i++)
 410                 ext2_free_blocks(inode, new_blocks[i], 1);
 411         return ret;
 412 }
 413
 414 /**
 415  *      ext2_alloc_branch - allocate and set up a chain of blocks.
 416  *      @inode: owner
 417  *      @num: depth of the chain (number of blocks to allocate)
 418  *      @offsets: offsets (in the blocks) to store the pointers to next.
 419  *      @branch: place to store the chain in.
 420  *
 421  *      This function allocates @num blocks, zeroes out all but the last one,
 422  *      links them into chain and (if we are synchronous) writes them to disk.
 423  *      In other words, it prepares a branch that can be spliced onto the
 424  *      inode. It stores the information about that chain in the branch[], in
 425  *      the same format as ext2_get_branch() would do. We are calling it after
 426  *      we had read the existing part of chain and partial points to the last
 427  *      triple of that (one with zero ->key). Upon the exit we have the same
 428  *      picture as after the successful ext2_get_block(), excpet that in one
 429  *      place chain is disconnected - *branch->p is still zero (we did not
 430  *      set the last link), but branch->key contains the number that should
 431  *      be placed into *branch->p to fill that gap.
 432  *
 433  *      If allocation fails we free all blocks we've allocated (and forget
 434  *      their buffer_heads) and return the error value the from failed
 435  *      ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 436  *      as described above and return 0.
 437  */
 438
 439 static int ext2_alloc_branch(struct inode *inode,
 440                         int indirect_blks, int *blks, ext2_fsblk_t goal,
 441                         int *offsets, Indirect *branch)
 442 {
 443         int blocksize = inode->i_sb->s_blocksize;
 444         int i, n = 0;
 445         int err = 0;
 446         struct buffer_head *bh;
 447         int num;
 448         ext2_fsblk_t new_blocks[4];
 449         ext2_fsblk_t current_block;
 450
 451         num = ext2_alloc_blocks(inode, goal, indirect_blks,
 452                                 *blks, new_blocks, &err);
 453         if (err)
 454                 return err;
 455
 456         branch[0].key = cpu_to_le32(new_blocks[0]);
 457         /*
 458          * metadata blocks and data blocks are allocated.
 459          */
 460         for (n = 1; n <= indirect_blks;  n++) {
 461                 /*
 462                  * Get buffer_head for parent block, zero it out
 463                  * and set the pointer to new one, then send
 464                  * parent to disk.
 465                  */
 466                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 467                 branch[n].bh = bh;
 468                 lock_buffer(bh);
 469                 memset(bh->b_data, 0, blocksize);
 470                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
 471                 branch[n].key = cpu_to_le32(new_blocks[n]);
 472                 *branch[n].p = branch[n].key;
 473                 if ( n == indirect_blks) {
 474                         current_block = new_blocks[n];
 475                         /*
 476                          * End of chain, update the last new metablock of
 477                          * the chain to point to the new allocated
 478                          * data blocks numbers
 479                          */
 480                         for (i=1; i < num; i++)
 481                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
 482                 }
 483                 set_buffer_uptodate(bh);
 484                 unlock_buffer(bh);
 485                 mark_buffer_dirty_inode(bh, inode);
 486                 /* We used to sync bh here if IS_SYNC(inode).
 487                  * But we now rely upon generic_osync_inode()
 488                  * and b_inode_buffers.  But not for directories.
 489                  */
 490                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
 491                         sync_dirty_buffer(bh);
 492         }
 493         *blks = num;
 494         return err;
 495 }
 496
 497 /**
 498  * ext2_splice_branch - splice the allocated branch onto inode.
 499  * @inode: owner
 500  * @block: (logical) number of block we are adding
 501  * @where: location of missing link
 502  * @num:   number of indirect blocks we are adding
 503  * @blks:  number of direct blocks we are adding
 504  *
 505  * This function fills the missing link and does all housekeeping needed in
 506  * inode (->i_blocks, etc.). In case of success we end up with the full
 507  * chain to new block and return 0.
 508  */
 509 static void ext2_splice_branch(struct inode *inode,
 510                         long block, Indirect *where, int num, int blks)
 511 {
 512         int i;
 513         struct ext2_block_alloc_info *block_i;
 514         ext2_fsblk_t current_block;
 515
 516         block_i = EXT2_I(inode)->i_block_alloc_info;
 517
 518         /* XXX LOCKING probably should have i_meta_lock ?*/
 519         /* That's it */
 520
 521         *where->p = where->key;
 522
 523         /*
 524          * Update the host buffer_head or inode to point to more just allocated
 525          * direct blocks blocks
 526          */
 527         if (num == 0 && blks > 1) {
 528                 current_block = le32_to_cpu(where->key) + 1;
 529                 for (i = 1; i < blks; i++)
 530                         *(where->p + i ) = cpu_to_le32(current_block++);
 531         }
 532
 533         /*
 534          * update the most recently allocated logical & physical block
 535          * in i_block_alloc_info, to assist find the proper goal block for next
 536          * allocation
 537          */
 538         if (block_i) {
 539                 block_i->last_alloc_logical_block = block + blks - 1;
 540                 block_i->last_alloc_physical_block =
 541                                 le32_to_cpu(where[num].key) + blks - 1;
 542         }
 543
 544         /* We are done with atomic stuff, now do the rest of housekeeping */
 545
 546         /* had we spliced it onto indirect block? */
 547         if (where->bh)
 548                 mark_buffer_dirty_inode(where->bh, inode);
 549
 550         inode->i_ctime = CURRENT_TIME_SEC;
 551         mark_inode_dirty(inode);
 552 }
 553
 554 /*
 555  * Allocation strategy is simple: if we have to allocate something, we will
 556  * have to go the whole way to leaf. So let's do it before attaching anything
 557  * to tree, set linkage between the newborn blocks, write them if sync is
 558  * required, recheck the path, free and repeat if check fails, otherwise
 559  * set the last missing link (that will protect us from any truncate-generated
 560  * removals - all blocks on the path are immune now) and possibly force the
 561  * write on the parent block.
 562  * That has a nice additional property: no special recovery from the failed
 563  * allocations is needed - we simply release blocks and do not touch anything
 564  * reachable from inode.
 565  *
 566  * `handle' can be NULL if create == 0.
 567  *
 568  * return > 0, # of blocks mapped or allocated.
 569  * return = 0, if plain lookup failed.
 570  * return < 0, error case.
 571  */
 572 static int ext2_get_blocks(struct inode *inode,
 573                            sector_t iblock, unsigned long maxblocks,
 574                            struct buffer_head *bh_result,
 575                            int create)
 576 {
 577         int err = -EIO;
 578         int offsets[4];
 579         Indirect chain[4];
 580         Indirect *partial;
 581         ext2_fsblk_t goal;
 582         int indirect_blks;
 583         int blocks_to_boundary = 0;
 584         int depth;
 585         struct ext2_inode_info *ei = EXT2_I(inode);
 586         int count = 0;
 587         ext2_fsblk_t first_block = 0;
 588
 589         depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 590
 591         if (depth == 0)
 592                 return (err);
 593
 594         partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 595         /* Simplest case - block found, no allocation needed */
 596         if (!partial) {
 597                 first_block = le32_to_cpu(chain[depth - 1].key);
 598                 clear_buffer_new(bh_result); /* What's this do? */
 599                 count++;
 600                 /*map more blocks*/
 601                 while (count < maxblocks && count <= blocks_to_boundary) {
 602                         ext2_fsblk_t blk;
 603
 604                         if (!verify_chain(chain, chain + depth - 1)) {
 605                                 /*
 606                                  * Indirect block might be removed by
 607                                  * truncate while we were reading it.
 608                                  * Handling of that case: forget what we've
 609                                  * got now, go to reread.
 610                                  */
 611                                 err = -EAGAIN;
 612                                 count = 0;
 613                                 break;
 614                         }
 615                         blk = le32_to_cpu(*(chain[depth-1].p + count));
 616                         if (blk == first_block + count)
 617                                 count++;
 618                         else
 619                                 break;
 620                 }
 621                 if (err != -EAGAIN)
 622                         goto got_it;
 623         }
 624
 625         /* Next simple case - plain lookup or failed read of indirect block */
 626         if (!create || err == -EIO)
 627                 goto cleanup;
 628
 629         mutex_lock(&ei->truncate_mutex);
 630         /*
 631          * If the indirect block is missing while we are reading
 632          * the chain(ext3_get_branch() returns -EAGAIN err), or
 633          * if the chain has been changed after we grab the semaphore,
 634          * (either because another process truncated this branch, or
 635          * another get_block allocated this branch) re-grab the chain to see if
 636          * the request block has been allocated or not.
 637          *
 638          * Since we already block the truncate/other get_block
 639          * at this point, we will have the current copy of the chain when we
 640          * splice the branch into the tree.
 641          */
 642         if (err == -EAGAIN || !verify_chain(chain, partial)) {
 643                 while (partial > chain) {
 644                         brelse(partial->bh);
 645                         partial--;
 646                 }
 647                 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 648                 if (!partial) {
 649                         count++;
 650                         mutex_unlock(&ei->truncate_mutex);
 651                         if (err)
 652                                 goto cleanup;
 653                         clear_buffer_new(bh_result);
 654                         goto got_it;
 655                 }
 656         }
 657
 658         /*
 659          * Okay, we need to do block allocation.  Lazily initialize the block
 660          * allocation info here if necessary
 661         */
 662         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
 663                 ext2_init_block_alloc_info(inode);
 664
 665         goal = ext2_find_goal(inode, iblock, partial);
 666
 667         /* the number of blocks need to allocate for [d,t]indirect blocks */
 668         indirect_blks = (chain + depth) - partial - 1;
 669         /*
 670          * Next look up the indirect map to count the totoal number of
 671          * direct blocks to allocate for this branch.
 672          */
 673         count = ext2_blks_to_allocate(partial, indirect_blks,
 674                                         maxblocks, blocks_to_boundary);
 675         /*
 676          * XXX ???? Block out ext2_truncate while we alter the tree
 677          */
 678         err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
 679                                 offsets + (partial - chain), partial);
 680
 681         if (err) {
 682                 mutex_unlock(&ei->truncate_mutex);
 683                 goto cleanup;
 684         }
 685
 686         if (ext2_use_xip(inode->i_sb)) {
 687                 /*
 688                  * we need to clear the block
 689                  */
 690                 err = ext2_clear_xip_target (inode,
 691                         le32_to_cpu(chain[depth-1].key));
 692                 if (err) {
 693                         mutex_unlock(&ei->truncate_mutex);
 694                         goto cleanup;
 695                 }
 696         }
 697
 698         ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
 699         mutex_unlock(&ei->truncate_mutex);
 700         set_buffer_new(bh_result);
 701 got_it:
 702         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
 703         if (count > blocks_to_boundary)
 704                 set_buffer_boundary(bh_result);
 705         err = count;
 706         /* Clean up and exit */
 707         partial = chain + depth - 1;    /* the whole chain */
 708 cleanup:
 709         while (partial > chain) {
 710                 brelse(partial->bh);
 711                 partial--;
 712         }
 713         return err;
 714 }
 715
 716 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
 717 {
 718         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
 719         int ret = ext2_get_blocks(inode, iblock, max_blocks,
 720                               bh_result, create);
 721         if (ret > 0) {
 722                 bh_result->b_size = (ret << inode->i_blkbits);
 723                 ret = 0;
 724         }
 725         return ret;
 726
 727 }
 728
 729 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 730                 u64 start, u64 len)
 731 {
 732         return generic_block_fiemap(inode, fieinfo, start, len,
 733                                     ext2_get_block);
 734 }
 735
 736 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
 737 {
 738         return block_write_full_page(page, ext2_get_block, wbc);
 739 }
 740
 741 static int ext2_readpage(struct file *file, struct page *page)
 742 {
 743         return mpage_readpage(page, ext2_get_block);
 744 }
 745
 746 static int
 747 ext2_readpages(struct file *file, struct address_space *mapping,
 748                 struct list_head *pages, unsigned nr_pages)
 749 {
 750         return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
 751 }
 752
 753 int __ext2_write_begin(struct file *file, struct address_space *mapping,
 754                 loff_t pos, unsigned len, unsigned flags,
 755                 struct page **pagep, void **fsdata)
 756 {
 757         return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 758                                                         ext2_get_block);
 759 }
 760
 761 static int
 762 ext2_write_begin(struct file *file, struct address_space *mapping,
 763                 loff_t pos, unsigned len, unsigned flags,
 764                 struct page **pagep, void **fsdata)
 765 {
 766         *pagep = NULL;
 767         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
 768 }
 769
 770 static int
 771 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
 772                 loff_t pos, unsigned len, unsigned flags,
 773                 struct page **pagep, void **fsdata)
 774 {
 775         /*
 776          * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
 777          * directory handling code to pass around offsets rather than struct
 778          * pages in order to make this work easily.
 779          */
 780         return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 781                                                         ext2_get_block);
 782 }
 783
 784 static int ext2_nobh_writepage(struct page *page,
 785                         struct writeback_control *wbc)
 786 {
 787         return nobh_writepage(page, ext2_get_block, wbc);
 788 }
 789
 790 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 791 {
 792         return generic_block_bmap(mapping,block,ext2_get_block);
 793 }
 794
 795 static ssize_t
 796 ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 797                         loff_t offset, unsigned long nr_segs)
 798 {
 799         struct file *file = iocb->ki_filp;
 800         struct inode *inode = file->f_mapping->host;
 801
 802         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 803                                 offset, nr_segs, ext2_get_block, NULL);
 804 }
 805
 806 static int
 807 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
 808 {
 809         return mpage_writepages(mapping, wbc, ext2_get_block);
 810 }
 811
 812 const struct address_space_operations ext2_aops = {
 813         .readpage               = ext2_readpage,
 814         .readpages              = ext2_readpages,
 815         .writepage              = ext2_writepage,
 816         .sync_page              = block_sync_page,
 817         .write_begin            = ext2_write_begin,
 818         .write_end              = generic_write_end,
 819         .bmap                   = ext2_bmap,
 820         .direct_IO              = ext2_direct_IO,
 821         .writepages             = ext2_writepages,
 822         .migratepage            = buffer_migrate_page,
 823         .is_partially_uptodate  = block_is_partially_uptodate,
 824 };
 825
 826 const struct address_space_operations ext2_aops_xip = {
 827         .bmap                   = ext2_bmap,
 828         .get_xip_mem            = ext2_get_xip_mem,
 829 };
 830
 831 const struct address_space_operations ext2_nobh_aops = {
 832         .readpage               = ext2_readpage,
 833         .readpages              = ext2_readpages,
 834         .writepage              = ext2_nobh_writepage,
 835         .sync_page              = block_sync_page,
 836         .write_begin            = ext2_nobh_write_begin,
 837         .write_end              = nobh_write_end,
 838         .bmap                   = ext2_bmap,
 839         .direct_IO              = ext2_direct_IO,
 840         .writepages             = ext2_writepages,
 841         .migratepage            = buffer_migrate_page,
 842 };
 843
 844 /*
 845  * Probably it should be a library function... search for first non-zero word
 846  * or memcmp with zero_page, whatever is better for particular architecture.
 847  * Linus?
 848  */
 849 static inline int all_zeroes(__le32 *p, __le32 *q)
 850 {
 851         while (p < q)
 852                 if (*p++)
 853                         return 0;
 854         return 1;
 855 }
 856
 857 /**
 858  *      ext2_find_shared - find the indirect blocks for partial truncation.
 859  *      @inode:   inode in question
 860  *      @depth:   depth of the affected branch
 861  *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
 862  *      @chain:   place to store the pointers to partial indirect blocks
 863  *      @top:     place to the (detached) top of branch
 864  *
 865  *      This is a helper function used by ext2_truncate().
 866  *
 867  *      When we do truncate() we may have to clean the ends of several indirect
 868  *      blocks but leave the blocks themselves alive. Block is partially
 869  *      truncated if some data below the new i_size is refered from it (and
 870  *      it is on the path to the first completely truncated data block, indeed).
 871  *      We have to free the top of that path along with everything to the right
 872  *      of the path. Since no allocation past the truncation point is possible
 873  *      until ext2_truncate() finishes, we may safely do the latter, but top
 874  *      of branch may require special attention - pageout below the truncation
 875  *      point might try to populate it.
 876  *
 877  *      We atomically detach the top of branch from the tree, store the block
 878  *      number of its root in *@top, pointers to buffer_heads of partially
 879  *      truncated blocks - in @chain[].bh and pointers to their last elements
 880  *      that should not be removed - in @chain[].p. Return value is the pointer
 881  *      to last filled element of @chain.
 882  *
 883  *      The work left to caller to do the actual freeing of subtrees:
 884  *              a) free the subtree starting from *@top
 885  *              b) free the subtrees whose roots are stored in
 886  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
 887  *              c) free the subtrees growing from the inode past the @chain[0].p
 888  *                      (no partially truncated stuff there).
 889  */
 890
 891 static Indirect *ext2_find_shared(struct inode *inode,
 892                                 int depth,
 893                                 int offsets[4],
 894                                 Indirect chain[4],
 895                                 __le32 *top)
 896 {
 897         Indirect *partial, *p;
 898         int k, err;
 899
 900         *top = 0;
 901         for (k = depth; k > 1 && !offsets[k-1]; k--)
 902                 ;
 903         partial = ext2_get_branch(inode, k, offsets, chain, &err);
 904         if (!partial)
 905                 partial = chain + k-1;
 906         /*
 907          * If the branch acquired continuation since we've looked at it -
 908          * fine, it should all survive and (new) top doesn't belong to us.
 909          */
 910         write_lock(&EXT2_I(inode)->i_meta_lock);
 911         if (!partial->key && *partial->p) {
 912                 write_unlock(&EXT2_I(inode)->i_meta_lock);
 913                 goto no_top;
 914         }
 915         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
 916                 ;
 917         /*
 918          * OK, we've found the last block that must survive. The rest of our
 919          * branch should be detached before unlocking. However, if that rest
 920          * of branch is all ours and does not grow immediately from the inode
 921          * it's easier to cheat and just decrement partial->p.
 922          */
 923         if (p == chain + k - 1 && p > chain) {
 924                 p->p--;
 925         } else {
 926                 *top = *p->p;
 927                 *p->p = 0;
 928         }
 929         write_unlock(&EXT2_I(inode)->i_meta_lock);
 930
 931         while(partial > p)
 932         {
 933                 brelse(partial->bh);
 934                 partial--;
 935         }
 936 no_top:
 937         return partial;
 938 }
 939
 940 /**
 941  *      ext2_free_data - free a list of data blocks
 942  *      @inode: inode we are dealing with
 943  *      @p:     array of block numbers
 944  *      @q:     points immediately past the end of array
 945  *
 946  *      We are freeing all blocks refered from that array (numbers are
 947  *      stored as little-endian 32-bit) and updating @inode->i_blocks
 948  *      appropriately.
 949  */
 950 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
 951 {
 952         unsigned long block_to_free = 0, count = 0;
 953         unsigned long nr;
 954
 955         for ( ; p < q ; p++) {
 956                 nr = le32_to_cpu(*p);
 957                 if (nr) {
 958                         *p = 0;
 959                         /* accumulate blocks to free if they're contiguous */
 960                         if (count == 0)
 961                                 goto free_this;
 962                         else if (block_to_free == nr - count)
 963                                 count++;
 964                         else {
 965                                 mark_inode_dirty(inode);
 966                                 ext2_free_blocks (inode, block_to_free, count);
 967                         free_this:
 968                                 block_to_free = nr;
 969                                 count = 1;
 970                         }
 971                 }
 972         }
 973         if (count > 0) {
 974                 mark_inode_dirty(inode);
 975                 ext2_free_blocks (inode, block_to_free, count);
 976         }
 977 }
 978
 979 /**
 980  *      ext2_free_branches - free an array of branches
 981  *      @inode: inode we are dealing with
 982  *      @p:     array of block numbers
 983  *      @q:     pointer immediately past the end of array
 984  *      @depth: depth of the branches to free
 985  *
 986  *      We are freeing all blocks refered from these branches (numbers are
 987  *      stored as little-endian 32-bit) and updating @inode->i_blocks
 988  *      appropriately.
 989  */
 990 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
 991 {
 992         struct buffer_head * bh;
 993         unsigned long nr;
 994
 995         if (depth--) {
 996                 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
 997                 for ( ; p < q ; p++) {
 998                         nr = le32_to_cpu(*p);
 999                         if (!nr)
1000                                 continue;
1001                         *p = 0;
1002                         bh = sb_bread(inode->i_sb, nr);
1003                         /*
1004                          * A read failure? Report error and clear slot
1005                          * (should be rare).
1006                          */
1007                         if (!bh) {
1008                                 ext2_error(inode->i_sb, "ext2_free_branches",
1009                                         "Read failure, inode=%ld, block=%ld",
1010                                         inode->i_ino, nr);
1011                                 continue;
1012                         }
1013                         ext2_free_branches(inode,
1014                                            (__le32*)bh->b_data,
1015                                            (__le32*)bh->b_data + addr_per_block,
1016                                            depth);
1017                         bforget(bh);
1018                         ext2_free_blocks(inode, nr, 1);
1019                         mark_inode_dirty(inode);
1020                 }
1021         } else
1022                 ext2_free_data(inode, p, q);
1023 }
1024
1025 void ext2_truncate(struct inode *inode)
1026 {
1027         __le32 *i_data = EXT2_I(inode)->i_data;
1028         struct ext2_inode_info *ei = EXT2_I(inode);
1029         int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1030         int offsets[4];
1031         Indirect chain[4];
1032         Indirect *partial;
1033         __le32 nr = 0;
1034         int n;
1035         long iblock;
1036         unsigned blocksize;
1037
1038         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1039             S_ISLNK(inode->i_mode)))
1040                 return;
1041         if (ext2_inode_is_fast_symlink(inode))
1042                 return;
1043         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1044                 return;
1045
1046         blocksize = inode->i_sb->s_blocksize;
1047         iblock = (inode->i_size + blocksize-1)
1048                                         >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1049
1050         if (mapping_is_xip(inode->i_mapping))
1051                 xip_truncate_page(inode->i_mapping, inode->i_size);
1052         else if (test_opt(inode->i_sb, NOBH))
1053                 nobh_truncate_page(inode->i_mapping,
1054                                 inode->i_size, ext2_get_block);
1055         else
1056                 block_truncate_page(inode->i_mapping,
1057                                 inode->i_size, ext2_get_block);
1058
1059         n = ext2_block_to_path(inode, iblock, offsets, NULL);
1060         if (n == 0)
1061                 return;
1062
1063         /*
1064          * From here we block out all ext2_get_block() callers who want to
1065          * modify the block allocation tree.
1066          */
1067         mutex_lock(&ei->truncate_mutex);
1068
1069         if (n == 1) {
1070                 ext2_free_data(inode, i_data+offsets[0],
1071                                         i_data + EXT2_NDIR_BLOCKS);
1072                 goto do_indirects;
1073         }
1074
1075         partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1076         /* Kill the top of shared branch (already detached) */
1077         if (nr) {
1078                 if (partial == chain)
1079                         mark_inode_dirty(inode);
1080                 else
1081                         mark_buffer_dirty_inode(partial->bh, inode);
1082                 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1083         }
1084         /* Clear the ends of indirect blocks on the shared branch */
1085         while (partial > chain) {
1086                 ext2_free_branches(inode,
1087                                    partial->p + 1,
1088                                    (__le32*)partial->bh->b_data+addr_per_block,
1089                                    (chain+n-1) - partial);
1090                 mark_buffer_dirty_inode(partial->bh, inode);
1091                 brelse (partial->bh);
1092                 partial--;
1093         }
1094 do_indirects:
1095         /* Kill the remaining (whole) subtrees */
1096         switch (offsets[0]) {
1097                 default:
1098                         nr = i_data[EXT2_IND_BLOCK];
1099                         if (nr) {
1100                                 i_data[EXT2_IND_BLOCK] = 0;
1101                                 mark_inode_dirty(inode);
1102                                 ext2_free_branches(inode, &nr, &nr+1, 1);
1103                         }
1104                 case EXT2_IND_BLOCK:
1105                         nr = i_data[EXT2_DIND_BLOCK];
1106                         if (nr) {
1107                                 i_data[EXT2_DIND_BLOCK] = 0;
1108                                 mark_inode_dirty(inode);
1109                                 ext2_free_branches(inode, &nr, &nr+1, 2);
1110                         }
1111                 case EXT2_DIND_BLOCK:
1112                         nr = i_data[EXT2_TIND_BLOCK];
1113                         if (nr) {
1114                                 i_data[EXT2_TIND_BLOCK] = 0;
1115                                 mark_inode_dirty(inode);
1116                                 ext2_free_branches(inode, &nr, &nr+1, 3);
1117                         }
1118                 case EXT2_TIND_BLOCK:
1119                         ;
1120         }
1121
1122         ext2_discard_reservation(inode);
1123
1124         mutex_unlock(&ei->truncate_mutex);
1125         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1126         if (inode_needs_sync(inode)) {
1127                 sync_mapping_buffers(inode->i_mapping);
1128                 ext2_sync_inode (inode);
1129         } else {
1130                 mark_inode_dirty(inode);
1131         }
1132 }
1133
1134 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1135                                         struct buffer_head **p)
1136 {
1137         struct buffer_head * bh;
1138         unsigned long block_group;
1139         unsigned long block;
1140         unsigned long offset;
1141         struct ext2_group_desc * gdp;
1142
1143         *p = NULL;
1144         if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1145             ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1146                 goto Einval;
1147
1148         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1149         gdp = ext2_get_group_desc(sb, block_group, NULL);
1150         if (!gdp)
1151                 goto Egdp;
1152         /*
1153          * Figure out the offset within the block group inode table
1154          */
1155         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1156         block = le32_to_cpu(gdp->bg_inode_table) +
1157                 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1158         if (!(bh = sb_bread(sb, block)))
1159                 goto Eio;
1160
1161         *p = bh;
1162         offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1163         return (struct ext2_inode *) (bh->b_data + offset);
1164
1165 Einval:
1166         ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1167                    (unsigned long) ino);
1168         return ERR_PTR(-EINVAL);
1169 Eio:
1170         ext2_error(sb, "ext2_get_inode",
1171                    "unable to read inode block - inode=%lu, block=%lu",
1172                    (unsigned long) ino, block);
1173 Egdp:
1174         return ERR_PTR(-EIO);
1175 }
1176
1177 void ext2_set_inode_flags(struct inode *inode)
1178 {
1179         unsigned int flags = EXT2_I(inode)->i_flags;
1180
1181         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1182         if (flags & EXT2_SYNC_FL)
1183                 inode->i_flags |= S_SYNC;
1184         if (flags & EXT2_APPEND_FL)
1185                 inode->i_flags |= S_APPEND;
1186         if (flags & EXT2_IMMUTABLE_FL)
1187                 inode->i_flags |= S_IMMUTABLE;
1188         if (flags & EXT2_NOATIME_FL)
1189                 inode->i_flags |= S_NOATIME;
1190         if (flags & EXT2_DIRSYNC_FL)
1191                 inode->i_flags |= S_DIRSYNC;
1192 }
1193
1194 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1195 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1196 {
1197         unsigned int flags = ei->vfs_inode.i_flags;
1198
1199         ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1200                         EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1201         if (flags & S_SYNC)
1202                 ei->i_flags |= EXT2_SYNC_FL;
1203         if (flags & S_APPEND)
1204                 ei->i_flags |= EXT2_APPEND_FL;
1205         if (flags & S_IMMUTABLE)
1206                 ei->i_flags |= EXT2_IMMUTABLE_FL;
1207         if (flags & S_NOATIME)
1208                 ei->i_flags |= EXT2_NOATIME_FL;
1209         if (flags & S_DIRSYNC)
1210                 ei->i_flags |= EXT2_DIRSYNC_FL;
1211 }
1212
1213 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1214 {
1215         struct ext2_inode_info *ei;
1216         struct buffer_head * bh;
1217         struct ext2_inode *raw_inode;
1218         struct inode *inode;
1219         long ret = -EIO;
1220         int n;
1221
1222         inode = iget_locked(sb, ino);
1223         if (!inode)
1224                 return ERR_PTR(-ENOMEM);
1225         if (!(inode->i_state & I_NEW))
1226                 return inode;
1227
1228         ei = EXT2_I(inode);
1229 #ifdef CONFIG_EXT2_FS_POSIX_ACL
1230         ei->i_acl = EXT2_ACL_NOT_CACHED;
1231         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1232 #endif
1233         ei->i_block_alloc_info = NULL;
1234
1235         raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1236         if (IS_ERR(raw_inode)) {
1237                 ret = PTR_ERR(raw_inode);
1238                 goto bad_inode;
1239         }
1240
1241         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1242         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1243         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1244         if (!(test_opt (inode->i_sb, NO_UID32))) {
1245                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1246                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1247         }
1248         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1249         inode->i_size = le32_to_cpu(raw_inode->i_size);
1250         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1251         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1252         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1253         inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1254         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1255         /* We now have enough fields to check if the inode was active or not.
1256          * This is needed because nfsd might try to access dead inodes
1257          * the test is that same one that e2fsck uses
1258          * NeilBrown 1999oct15
1259          */
1260         if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1261                 /* this inode is deleted */
1262                 brelse (bh);
1263                 ret = -ESTALE;
1264                 goto bad_inode;
1265         }
1266         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1267         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1268         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1269         ei->i_frag_no = raw_inode->i_frag;
1270         ei->i_frag_size = raw_inode->i_fsize;
1271         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1272         ei->i_dir_acl = 0;
1273         if (S_ISREG(inode->i_mode))
1274                 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1275         else
1276                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1277         ei->i_dtime = 0;
1278         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1279         ei->i_state = 0;
1280         ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1281         ei->i_dir_start_lookup = 0;
1282
1283         /*
1284          * NOTE! The in-memory inode i_data array is in little-endian order
1285          * even on big-endian machines: we do NOT byteswap the block numbers!
1286          */
1287         for (n = 0; n < EXT2_N_BLOCKS; n++)
1288                 ei->i_data[n] = raw_inode->i_block[n];
1289
1290         if (S_ISREG(inode->i_mode)) {
1291                 inode->i_op = &ext2_file_inode_operations;
1292                 if (ext2_use_xip(inode->i_sb)) {
1293                         inode->i_mapping->a_ops = &ext2_aops_xip;
1294                         inode->i_fop = &ext2_xip_file_operations;
1295                 } else if (test_opt(inode->i_sb, NOBH)) {
1296                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1297                         inode->i_fop = &ext2_file_operations;
1298                 } else {
1299                         inode->i_mapping->a_ops = &ext2_aops;
1300                         inode->i_fop = &ext2_file_operations;
1301                 }
1302         } else if (S_ISDIR(inode->i_mode)) {
1303                 inode->i_op = &ext2_dir_inode_operations;
1304                 inode->i_fop = &ext2_dir_operations;
1305                 if (test_opt(inode->i_sb, NOBH))
1306                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1307                 else
1308                         inode->i_mapping->a_ops = &ext2_aops;
1309         } else if (S_ISLNK(inode->i_mode)) {
1310                 if (ext2_inode_is_fast_symlink(inode)) {
1311                         inode->i_op = &ext2_fast_symlink_inode_operations;
1312                         nd_terminate_link(ei->i_data, inode->i_size,
1313                                 sizeof(ei->i_data) - 1);
1314                 } else {
1315                         inode->i_op = &ext2_symlink_inode_operations;
1316                         if (test_opt(inode->i_sb, NOBH))
1317                                 inode->i_mapping->a_ops = &ext2_nobh_aops;
1318                         else
1319                                 inode->i_mapping->a_ops = &ext2_aops;
1320                 }
1321         } else {
1322                 inode->i_op = &ext2_special_inode_operations;
1323                 if (raw_inode->i_block[0])
1324                         init_special_inode(inode, inode->i_mode,
1325                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1326                 else
1327                         init_special_inode(inode, inode->i_mode,
1328                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1329         }
1330         brelse (bh);
1331         ext2_set_inode_flags(inode);
1332         unlock_new_inode(inode);
1333         return inode;
1334
1335 bad_inode:
1336         iget_failed(inode);
1337         return ERR_PTR(ret);
1338 }
1339
1340 static int ext2_update_inode(struct inode * inode, int do_sync)
1341 {
1342         struct ext2_inode_info *ei = EXT2_I(inode);
1343         struct super_block *sb = inode->i_sb;
1344         ino_t ino = inode->i_ino;
1345         uid_t uid = inode->i_uid;
1346         gid_t gid = inode->i_gid;
1347         struct buffer_head * bh;
1348         struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1349         int n;
1350         int err = 0;
1351
1352         if (IS_ERR(raw_inode))
1353                 return -EIO;
1354
1355         /* For fields not not tracking in the in-memory inode,
1356          * initialise them to zero for new inodes. */
1357         if (ei->i_state & EXT2_STATE_NEW)
1358                 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1359
1360         ext2_get_inode_flags(ei);
1361         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1362         if (!(test_opt(sb, NO_UID32))) {
1363                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1364                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1365 /*
1366  * Fix up interoperability with old kernels. Otherwise, old inodes get
1367  * re-used with the upper 16 bits of the uid/gid intact
1368  */
1369                 if (!ei->i_dtime) {
1370                         raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1371                         raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1372                 } else {
1373                         raw_inode->i_uid_high = 0;
1374                         raw_inode->i_gid_high = 0;
1375                 }
1376         } else {
1377                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1378                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1379                 raw_inode->i_uid_high = 0;
1380                 raw_inode->i_gid_high = 0;
1381         }
1382         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1383         raw_inode->i_size = cpu_to_le32(inode->i_size);
1384         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1385         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1386         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1387
1388         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1389         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1390         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1391         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1392         raw_inode->i_frag = ei->i_frag_no;
1393         raw_inode->i_fsize = ei->i_frag_size;
1394         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1395         if (!S_ISREG(inode->i_mode))
1396                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1397         else {
1398                 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1399                 if (inode->i_size > 0x7fffffffULL) {
1400                         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1401                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1402                             EXT2_SB(sb)->s_es->s_rev_level ==
1403                                         cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1404                                /* If this is the first large file
1405                                 * created, add a flag to the superblock.
1406                                 */
1407                                 lock_kernel();
1408                                 ext2_update_dynamic_rev(sb);
1409                                 EXT2_SET_RO_COMPAT_FEATURE(sb,
1410                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1411                                 unlock_kernel();
1412                                 ext2_write_super(sb);
1413                         }
1414                 }
1415         }
1416
1417         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1418         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1419                 if (old_valid_dev(inode->i_rdev)) {
1420                         raw_inode->i_block[0] =
1421                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
1422                         raw_inode->i_block[1] = 0;
1423                 } else {
1424                         raw_inode->i_block[0] = 0;
1425                         raw_inode->i_block[1] =
1426                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
1427                         raw_inode->i_block[2] = 0;
1428                 }
1429         } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1430                 raw_inode->i_block[n] = ei->i_data[n];
1431         mark_buffer_dirty(bh);
1432         if (do_sync) {
1433                 sync_dirty_buffer(bh);
1434                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1435                         printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1436                                 sb->s_id, (unsigned long) ino);
1437                         err = -EIO;
1438                 }
1439         }
1440         ei->i_state &= ~EXT2_STATE_NEW;
1441         brelse (bh);
1442         return err;
1443 }
1444
1445 int ext2_write_inode(struct inode *inode, int wait)
1446 {
1447         return ext2_update_inode(inode, wait);
1448 }
1449
1450 int ext2_sync_inode(struct inode *inode)
1451 {
1452         struct writeback_control wbc = {
1453                 .sync_mode = WB_SYNC_ALL,
1454                 .nr_to_write = 0,       /* sys_fsync did this */
1455         };
1456         return sync_inode(inode, &wbc);
1457 }
1458
1459 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1460 {
1461         struct inode *inode = dentry->d_inode;
1462         int error;
1463
1464         error = inode_change_ok(inode, iattr);
1465         if (error)
1466                 return error;
1467         if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1468             (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1469                 error = vfs_dq_transfer(inode, iattr) ? -EDQUOT : 0;
1470                 if (error)
1471                         return error;
1472         }
1473         error = inode_setattr(inode, iattr);
1474         if (!error && (iattr->ia_valid & ATTR_MODE))
1475                 error = ext2_acl_chmod(inode);
1476         return error;
1477 }