fs/gfs2/dir.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License version 2.
   8  */
   9
  10 /*
  11  * Implements Extendible Hashing as described in:
  12  *   "Extendible Hashing" by Fagin, et al in
  13  *     __ACM Trans. on Database Systems__, Sept 1979.
  14  *
  15  *
  16  * Here's the layout of dirents which is essentially the same as that of ext2
  17  * within a single block. The field de_name_len is the number of bytes
  18  * actually required for the name (no null terminator). The field de_rec_len
  19  * is the number of bytes allocated to the dirent. The offset of the next
  20  * dirent in the block is (dirent + dirent->de_rec_len). When a dirent is
  21  * deleted, the preceding dirent inherits its allocated space, ie
  22  * prev->de_rec_len += deleted->de_rec_len. Since the next dirent is obtained
  23  * by adding de_rec_len to the current dirent, this essentially causes the
  24  * deleted dirent to get jumped over when iterating through all the dirents.
  25  *
  26  * When deleting the first dirent in a block, there is no previous dirent so
  27  * the field de_ino is set to zero to designate it as deleted. When allocating
  28  * a dirent, gfs2_dirent_alloc iterates through the dirents in a block. If the
  29  * first dirent has (de_ino == 0) and de_rec_len is large enough, this first
  30  * dirent is allocated. Otherwise it must go through all the 'used' dirents
  31  * searching for one in which the amount of total space minus the amount of
  32  * used space will provide enough space for the new dirent.
  33  *
  34  * There are two types of blocks in which dirents reside. In a stuffed dinode,
  35  * the dirents begin at offset sizeof(struct gfs2_dinode) from the beginning of
  36  * the block.  In leaves, they begin at offset sizeof(struct gfs2_leaf) from the
  37  * beginning of the leaf block. The dirents reside in leaves when
  38  *
  39  * dip->i_diskflags & GFS2_DIF_EXHASH is true
  40  *
  41  * Otherwise, the dirents are "linear", within a single stuffed dinode block.
  42  *
  43  * When the dirents are in leaves, the actual contents of the directory file are
  44  * used as an array of 64-bit block pointers pointing to the leaf blocks. The
  45  * dirents are NOT in the directory file itself. There can be more than one
  46  * block pointer in the array that points to the same leaf. In fact, when a
  47  * directory is first converted from linear to exhash, all of the pointers
  48  * point to the same leaf.
  49  *
  50  * When a leaf is completely full, the size of the hash table can be
  51  * doubled unless it is already at the maximum size which is hard coded into
  52  * GFS2_DIR_MAX_DEPTH. After that, leaves are chained together in a linked list,
  53  * but never before the maximum hash table size has been reached.
  54  */
  55
  56 #include <linux/slab.h>
  57 #include <linux/spinlock.h>
  58 #include <linux/buffer_head.h>
  59 #include <linux/sort.h>
  60 #include <linux/gfs2_ondisk.h>
  61 #include <linux/crc32.h>
  62 #include <linux/vmalloc.h>
  63
  64 #include "gfs2.h"
  65 #include "incore.h"
  66 #include "dir.h"
  67 #include "glock.h"
  68 #include "inode.h"
  69 #include "meta_io.h"
  70 #include "quota.h"
  71 #include "rgrp.h"
  72 #include "trans.h"
  73 #include "bmap.h"
  74 #include "util.h"
  75
  76 #define IS_LEAF     1 /* Hashed (leaf) directory */
  77 #define IS_DINODE   2 /* Linear (stuffed dinode block) directory */
  78
  79 #define gfs2_disk_hash2offset(h) (((u64)(h)) >> 1)
  80 #define gfs2_dir_offset2hash(p) ((u32)(((u64)(p)) << 1))
  81
  82 struct qstr gfs2_qdot __read_mostly;
  83 struct qstr gfs2_qdotdot __read_mostly;
  84
  85 typedef int (*gfs2_dscan_t)(const struct gfs2_dirent *dent,
  86                             const struct qstr *name, void *opaque);
  87
  88 int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
  89                             struct buffer_head **bhp)
  90 {
  91         struct buffer_head *bh;
  92
  93         bh = gfs2_meta_new(ip->i_gl, block);
  94         gfs2_trans_add_bh(ip->i_gl, bh, 1);
  95         gfs2_metatype_set(bh, GFS2_METATYPE_JD, GFS2_FORMAT_JD);
  96         gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
  97         *bhp = bh;
  98         return 0;
  99 }
 100
 101 static int gfs2_dir_get_existing_buffer(struct gfs2_inode *ip, u64 block,
 102                                         struct buffer_head **bhp)
 103 {
 104         struct buffer_head *bh;
 105         int error;
 106
 107         error = gfs2_meta_read(ip->i_gl, block, DIO_WAIT, &bh);
 108         if (error)
 109                 return error;
 110         if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_JD)) {
 111                 brelse(bh);
 112                 return -EIO;
 113         }
 114         *bhp = bh;
 115         return 0;
 116 }
 117
 118 static int gfs2_dir_write_stuffed(struct gfs2_inode *ip, const char *buf,
 119                                   unsigned int offset, unsigned int size)
 120 {
 121         struct buffer_head *dibh;
 122         int error;
 123
 124         error = gfs2_meta_inode_buffer(ip, &dibh);
 125         if (error)
 126                 return error;
 127
 128         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 129         memcpy(dibh->b_data + offset + sizeof(struct gfs2_dinode), buf, size);
 130         if (ip->i_inode.i_size < offset + size)
 131                 i_size_write(&ip->i_inode, offset + size);
 132         ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
 133         gfs2_dinode_out(ip, dibh->b_data);
 134
 135         brelse(dibh);
 136
 137         return size;
 138 }
 139
 140
 141
 142 /**
 143  * gfs2_dir_write_data - Write directory information to the inode
 144  * @ip: The GFS2 inode
 145  * @buf: The buffer containing information to be written
 146  * @offset: The file offset to start writing at
 147  * @size: The amount of data to write
 148  *
 149  * Returns: The number of bytes correctly written or error code
 150  */
 151 static int gfs2_dir_write_data(struct gfs2_inode *ip, const char *buf,
 152                                u64 offset, unsigned int size)
 153 {
 154         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 155         struct buffer_head *dibh;
 156         u64 lblock, dblock;
 157         u32 extlen = 0;
 158         unsigned int o;
 159         int copied = 0;
 160         int error = 0;
 161         int new = 0;
 162
 163         if (!size)
 164                 return 0;
 165
 166         if (gfs2_is_stuffed(ip) &&
 167             offset + size <= sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
 168                 return gfs2_dir_write_stuffed(ip, buf, (unsigned int)offset,
 169                                               size);
 170
 171         if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
 172                 return -EINVAL;
 173
 174         if (gfs2_is_stuffed(ip)) {
 175                 error = gfs2_unstuff_dinode(ip, NULL);
 176                 if (error)
 177                         return error;
 178         }
 179
 180         lblock = offset;
 181         o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
 182
 183         while (copied < size) {
 184                 unsigned int amount;
 185                 struct buffer_head *bh;
 186
 187                 amount = size - copied;
 188                 if (amount > sdp->sd_sb.sb_bsize - o)
 189                         amount = sdp->sd_sb.sb_bsize - o;
 190
 191                 if (!extlen) {
 192                         new = 1;
 193                         error = gfs2_extent_map(&ip->i_inode, lblock, &new,
 194                                                 &dblock, &extlen);
 195                         if (error)
 196                                 goto fail;
 197                         error = -EIO;
 198                         if (gfs2_assert_withdraw(sdp, dblock))
 199                                 goto fail;
 200                 }
 201
 202                 if (amount == sdp->sd_jbsize || new)
 203                         error = gfs2_dir_get_new_buffer(ip, dblock, &bh);
 204                 else
 205                         error = gfs2_dir_get_existing_buffer(ip, dblock, &bh);
 206
 207                 if (error)
 208                         goto fail;
 209
 210                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 211                 memcpy(bh->b_data + o, buf, amount);
 212                 brelse(bh);
 213
 214                 buf += amount;
 215                 copied += amount;
 216                 lblock++;
 217                 dblock++;
 218                 extlen--;
 219
 220                 o = sizeof(struct gfs2_meta_header);
 221         }
 222
 223 out:
 224         error = gfs2_meta_inode_buffer(ip, &dibh);
 225         if (error)
 226                 return error;
 227
 228         if (ip->i_inode.i_size < offset + copied)
 229                 i_size_write(&ip->i_inode, offset + copied);
 230         ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
 231
 232         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 233         gfs2_dinode_out(ip, dibh->b_data);
 234         brelse(dibh);
 235
 236         return copied;
 237 fail:
 238         if (copied)
 239                 goto out;
 240         return error;
 241 }
 242
 243 static int gfs2_dir_read_stuffed(struct gfs2_inode *ip, char *buf,
 244                                  u64 offset, unsigned int size)
 245 {
 246         struct buffer_head *dibh;
 247         int error;
 248
 249         error = gfs2_meta_inode_buffer(ip, &dibh);
 250         if (!error) {
 251                 offset += sizeof(struct gfs2_dinode);
 252                 memcpy(buf, dibh->b_data + offset, size);
 253                 brelse(dibh);
 254         }
 255
 256         return (error) ? error : size;
 257 }
 258
 259
 260 /**
 261  * gfs2_dir_read_data - Read a data from a directory inode
 262  * @ip: The GFS2 Inode
 263  * @buf: The buffer to place result into
 264  * @offset: File offset to begin jdata_readng from
 265  * @size: Amount of data to transfer
 266  *
 267  * Returns: The amount of data actually copied or the error
 268  */
 269 static int gfs2_dir_read_data(struct gfs2_inode *ip, char *buf, u64 offset,
 270                               unsigned int size, unsigned ra)
 271 {
 272         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 273         u64 lblock, dblock;
 274         u32 extlen = 0;
 275         unsigned int o;
 276         int copied = 0;
 277         int error = 0;
 278         u64 disksize = i_size_read(&ip->i_inode);
 279
 280         if (offset >= disksize)
 281                 return 0;
 282
 283         if (offset + size > disksize)
 284                 size = disksize - offset;
 285
 286         if (!size)
 287                 return 0;
 288
 289         if (gfs2_is_stuffed(ip))
 290                 return gfs2_dir_read_stuffed(ip, buf, offset, size);
 291
 292         if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip)))
 293                 return -EINVAL;
 294
 295         lblock = offset;
 296         o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header);
 297
 298         while (copied < size) {
 299                 unsigned int amount;
 300                 struct buffer_head *bh;
 301                 int new;
 302
 303                 amount = size - copied;
 304                 if (amount > sdp->sd_sb.sb_bsize - o)
 305                         amount = sdp->sd_sb.sb_bsize - o;
 306
 307                 if (!extlen) {
 308                         new = 0;
 309                         error = gfs2_extent_map(&ip->i_inode, lblock, &new,
 310                                                 &dblock, &extlen);
 311                         if (error || !dblock)
 312                                 goto fail;
 313                         BUG_ON(extlen < 1);
 314                         if (!ra)
 315                                 extlen = 1;
 316                         bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);
 317                 } else {
 318                         error = gfs2_meta_read(ip->i_gl, dblock, DIO_WAIT, &bh);
 319                         if (error)
 320                                 goto fail;
 321                 }
 322                 error = gfs2_metatype_check(sdp, bh, GFS2_METATYPE_JD);
 323                 if (error) {
 324                         brelse(bh);
 325                         goto fail;
 326                 }
 327                 dblock++;
 328                 extlen--;
 329                 memcpy(buf, bh->b_data + o, amount);
 330                 brelse(bh);
 331                 buf += amount;
 332                 copied += amount;
 333                 lblock++;
 334                 o = sizeof(struct gfs2_meta_header);
 335         }
 336
 337         return copied;
 338 fail:
 339         return (copied) ? copied : error;
 340 }
 341
 342 static inline int gfs2_dirent_sentinel(const struct gfs2_dirent *dent)
 343 {
 344         return dent->de_inum.no_addr == 0 || dent->de_inum.no_formal_ino == 0;
 345 }
 346
 347 static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent,
 348                                      const struct qstr *name, int ret)
 349 {
 350         if (!gfs2_dirent_sentinel(dent) &&
 351             be32_to_cpu(dent->de_hash) == name->hash &&
 352             be16_to_cpu(dent->de_name_len) == name->len &&
 353             memcmp(dent+1, name->name, name->len) == 0)
 354                 return ret;
 355         return 0;
 356 }
 357
 358 static int gfs2_dirent_find(const struct gfs2_dirent *dent,
 359                             const struct qstr *name,
 360                             void *opaque)
 361 {
 362         return __gfs2_dirent_find(dent, name, 1);
 363 }
 364
 365 static int gfs2_dirent_prev(const struct gfs2_dirent *dent,
 366                             const struct qstr *name,
 367                             void *opaque)
 368 {
 369         return __gfs2_dirent_find(dent, name, 2);
 370 }
 371
 372 /*
 373  * name->name holds ptr to start of block.
 374  * name->len holds size of block.
 375  */
 376 static int gfs2_dirent_last(const struct gfs2_dirent *dent,
 377                             const struct qstr *name,
 378                             void *opaque)
 379 {
 380         const char *start = name->name;
 381         const char *end = (const char *)dent + be16_to_cpu(dent->de_rec_len);
 382         if (name->len == (end - start))
 383                 return 1;
 384         return 0;
 385 }
 386
 387 static int gfs2_dirent_find_space(const struct gfs2_dirent *dent,
 388                                   const struct qstr *name,
 389                                   void *opaque)
 390 {
 391         unsigned required = GFS2_DIRENT_SIZE(name->len);
 392         unsigned actual = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
 393         unsigned totlen = be16_to_cpu(dent->de_rec_len);
 394
 395         if (gfs2_dirent_sentinel(dent))
 396                 actual = 0;
 397         if (totlen - actual >= required)
 398                 return 1;
 399         return 0;
 400 }
 401
 402 struct dirent_gather {
 403         const struct gfs2_dirent **pdent;
 404         unsigned offset;
 405 };
 406
 407 static int gfs2_dirent_gather(const struct gfs2_dirent *dent,
 408                               const struct qstr *name,
 409                               void *opaque)
 410 {
 411         struct dirent_gather *g = opaque;
 412         if (!gfs2_dirent_sentinel(dent)) {
 413                 g->pdent[g->offset++] = dent;
 414         }
 415         return 0;
 416 }
 417
 418 /*
 419  * Other possible things to check:
 420  * - Inode located within filesystem size (and on valid block)
 421  * - Valid directory entry type
 422  * Not sure how heavy-weight we want to make this... could also check
 423  * hash is correct for example, but that would take a lot of extra time.
 424  * For now the most important thing is to check that the various sizes
 425  * are correct.
 426  */
 427 static int gfs2_check_dirent(struct gfs2_dirent *dent, unsigned int offset,
 428                              unsigned int size, unsigned int len, int first)
 429 {
 430         const char *msg = "gfs2_dirent too small";
 431         if (unlikely(size < sizeof(struct gfs2_dirent)))
 432                 goto error;
 433         msg = "gfs2_dirent misaligned";
 434         if (unlikely(offset & 0x7))
 435                 goto error;
 436         msg = "gfs2_dirent points beyond end of block";
 437         if (unlikely(offset + size > len))
 438                 goto error;
 439         msg = "zero inode number";
 440         if (unlikely(!first && gfs2_dirent_sentinel(dent)))
 441                 goto error;
 442         msg = "name length is greater than space in dirent";
 443         if (!gfs2_dirent_sentinel(dent) &&
 444             unlikely(sizeof(struct gfs2_dirent)+be16_to_cpu(dent->de_name_len) >
 445                      size))
 446                 goto error;
 447         return 0;
 448 error:
 449         printk(KERN_WARNING "gfs2_check_dirent: %s (%s)\n", msg,
 450                first ? "first in block" : "not first in block");
 451         return -EIO;
 452 }
 453
 454 static int gfs2_dirent_offset(const void *buf)
 455 {
 456         const struct gfs2_meta_header *h = buf;
 457         int offset;
 458
 459         BUG_ON(buf == NULL);
 460
 461         switch(be32_to_cpu(h->mh_type)) {
 462         case GFS2_METATYPE_LF:
 463                 offset = sizeof(struct gfs2_leaf);
 464                 break;
 465         case GFS2_METATYPE_DI:
 466                 offset = sizeof(struct gfs2_dinode);
 467                 break;
 468         default:
 469                 goto wrong_type;
 470         }
 471         return offset;
 472 wrong_type:
 473         printk(KERN_WARNING "gfs2_scan_dirent: wrong block type %u\n",
 474                be32_to_cpu(h->mh_type));
 475         return -1;
 476 }
 477
 478 static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
 479                                             unsigned int len, gfs2_dscan_t scan,
 480                                             const struct qstr *name,
 481                                             void *opaque)
 482 {
 483         struct gfs2_dirent *dent, *prev;
 484         unsigned offset;
 485         unsigned size;
 486         int ret = 0;
 487
 488         ret = gfs2_dirent_offset(buf);
 489         if (ret < 0)
 490                 goto consist_inode;
 491
 492         offset = ret;
 493         prev = NULL;
 494         dent = buf + offset;
 495         size = be16_to_cpu(dent->de_rec_len);
 496         if (gfs2_check_dirent(dent, offset, size, len, 1))
 497                 goto consist_inode;
 498         do {
 499                 ret = scan(dent, name, opaque);
 500                 if (ret)
 501                         break;
 502                 offset += size;
 503                 if (offset == len)
 504                         break;
 505                 prev = dent;
 506                 dent = buf + offset;
 507                 size = be16_to_cpu(dent->de_rec_len);
 508                 if (gfs2_check_dirent(dent, offset, size, len, 0))
 509                         goto consist_inode;
 510         } while(1);
 511
 512         switch(ret) {
 513         case 0:
 514                 return NULL;
 515         case 1:
 516                 return dent;
 517         case 2:
 518                 return prev ? prev : dent;
 519         default:
 520                 BUG_ON(ret > 0);
 521                 return ERR_PTR(ret);
 522         }
 523
 524 consist_inode:
 525         gfs2_consist_inode(GFS2_I(inode));
 526         return ERR_PTR(-EIO);
 527 }
 528
 529 static int dirent_check_reclen(struct gfs2_inode *dip,
 530                                const struct gfs2_dirent *d, const void *end_p)
 531 {
 532         const void *ptr = d;
 533         u16 rec_len = be16_to_cpu(d->de_rec_len);
 534
 535         if (unlikely(rec_len < sizeof(struct gfs2_dirent)))
 536                 goto broken;
 537         ptr += rec_len;
 538         if (ptr < end_p)
 539                 return rec_len;
 540         if (ptr == end_p)
 541                 return -ENOENT;
 542 broken:
 543         gfs2_consist_inode(dip);
 544         return -EIO;
 545 }
 546
 547 /**
 548  * dirent_next - Next dirent
 549  * @dip: the directory
 550  * @bh: The buffer
 551  * @dent: Pointer to list of dirents
 552  *
 553  * Returns: 0 on success, error code otherwise
 554  */
 555
 556 static int dirent_next(struct gfs2_inode *dip, struct buffer_head *bh,
 557                        struct gfs2_dirent **dent)
 558 {
 559         struct gfs2_dirent *cur = *dent, *tmp;
 560         char *bh_end = bh->b_data + bh->b_size;
 561         int ret;
 562
 563         ret = dirent_check_reclen(dip, cur, bh_end);
 564         if (ret < 0)
 565                 return ret;
 566
 567         tmp = (void *)cur + ret;
 568         ret = dirent_check_reclen(dip, tmp, bh_end);
 569         if (ret == -EIO)
 570                 return ret;
 571
 572         /* Only the first dent could ever have de_inum.no_addr == 0 */
 573         if (gfs2_dirent_sentinel(tmp)) {
 574                 gfs2_consist_inode(dip);
 575                 return -EIO;
 576         }
 577
 578         *dent = tmp;
 579         return 0;
 580 }
 581
 582 /**
 583  * dirent_del - Delete a dirent
 584  * @dip: The GFS2 inode
 585  * @bh: The buffer
 586  * @prev: The previous dirent
 587  * @cur: The current dirent
 588  *
 589  */
 590
 591 static void dirent_del(struct gfs2_inode *dip, struct buffer_head *bh,
 592                        struct gfs2_dirent *prev, struct gfs2_dirent *cur)
 593 {
 594         u16 cur_rec_len, prev_rec_len;
 595
 596         if (gfs2_dirent_sentinel(cur)) {
 597                 gfs2_consist_inode(dip);
 598                 return;
 599         }
 600
 601         gfs2_trans_add_bh(dip->i_gl, bh, 1);
 602
 603         /* If there is no prev entry, this is the first entry in the block.
 604            The de_rec_len is already as big as it needs to be.  Just zero
 605            out the inode number and return.  */
 606
 607         if (!prev) {
 608                 cur->de_inum.no_addr = 0;
 609                 cur->de_inum.no_formal_ino = 0;
 610                 return;
 611         }
 612
 613         /*  Combine this dentry with the previous one.  */
 614
 615         prev_rec_len = be16_to_cpu(prev->de_rec_len);
 616         cur_rec_len = be16_to_cpu(cur->de_rec_len);
 617
 618         if ((char *)prev + prev_rec_len != (char *)cur)
 619                 gfs2_consist_inode(dip);
 620         if ((char *)cur + cur_rec_len > bh->b_data + bh->b_size)
 621                 gfs2_consist_inode(dip);
 622
 623         prev_rec_len += cur_rec_len;
 624         prev->de_rec_len = cpu_to_be16(prev_rec_len);
 625 }
 626
 627 /*
 628  * Takes a dent from which to grab space as an argument. Returns the
 629  * newly created dent.
 630  */
 631 static struct gfs2_dirent *gfs2_init_dirent(struct inode *inode,
 632                                             struct gfs2_dirent *dent,
 633                                             const struct qstr *name,
 634                                             struct buffer_head *bh)
 635 {
 636         struct gfs2_inode *ip = GFS2_I(inode);
 637         struct gfs2_dirent *ndent;
 638         unsigned offset = 0, totlen;
 639
 640         if (!gfs2_dirent_sentinel(dent))
 641                 offset = GFS2_DIRENT_SIZE(be16_to_cpu(dent->de_name_len));
 642         totlen = be16_to_cpu(dent->de_rec_len);
 643         BUG_ON(offset + name->len > totlen);
 644         gfs2_trans_add_bh(ip->i_gl, bh, 1);
 645         ndent = (struct gfs2_dirent *)((char *)dent + offset);
 646         dent->de_rec_len = cpu_to_be16(offset);
 647         gfs2_qstr2dirent(name, totlen - offset, ndent);
 648         return ndent;
 649 }
 650
 651 static struct gfs2_dirent *gfs2_dirent_alloc(struct inode *inode,
 652                                              struct buffer_head *bh,
 653                                              const struct qstr *name)
 654 {
 655         struct gfs2_dirent *dent;
 656         dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
 657                                 gfs2_dirent_find_space, name, NULL);
 658         if (!dent || IS_ERR(dent))
 659                 return dent;
 660         return gfs2_init_dirent(inode, dent, name, bh);
 661 }
 662
 663 static int get_leaf(struct gfs2_inode *dip, u64 leaf_no,
 664                     struct buffer_head **bhp)
 665 {
 666         int error;
 667
 668         error = gfs2_meta_read(dip->i_gl, leaf_no, DIO_WAIT, bhp);
 669         if (!error && gfs2_metatype_check(GFS2_SB(&dip->i_inode), *bhp, GFS2_METATYPE_LF)) {
 670                 /* printk(KERN_INFO "block num=%llu\n", leaf_no); */
 671                 error = -EIO;
 672         }
 673
 674         return error;
 675 }
 676
 677 /**
 678  * get_leaf_nr - Get a leaf number associated with the index
 679  * @dip: The GFS2 inode
 680  * @index:
 681  * @leaf_out:
 682  *
 683  * Returns: 0 on success, error code otherwise
 684  */
 685
 686 static int get_leaf_nr(struct gfs2_inode *dip, u32 index,
 687                        u64 *leaf_out)
 688 {
 689         __be64 leaf_no;
 690         int error;
 691
 692         error = gfs2_dir_read_data(dip, (char *)&leaf_no,
 693                                     index * sizeof(__be64),
 694                                     sizeof(__be64), 0);
 695         if (error != sizeof(u64))
 696                 return (error < 0) ? error : -EIO;
 697
 698         *leaf_out = be64_to_cpu(leaf_no);
 699
 700         return 0;
 701 }
 702
 703 static int get_first_leaf(struct gfs2_inode *dip, u32 index,
 704                           struct buffer_head **bh_out)
 705 {
 706         u64 leaf_no;
 707         int error;
 708
 709         error = get_leaf_nr(dip, index, &leaf_no);
 710         if (!error)
 711                 error = get_leaf(dip, leaf_no, bh_out);
 712
 713         return error;
 714 }
 715
 716 static struct gfs2_dirent *gfs2_dirent_search(struct inode *inode,
 717                                               const struct qstr *name,
 718                                               gfs2_dscan_t scan,
 719                                               struct buffer_head **pbh)
 720 {
 721         struct buffer_head *bh;
 722         struct gfs2_dirent *dent;
 723         struct gfs2_inode *ip = GFS2_I(inode);
 724         int error;
 725
 726         if (ip->i_diskflags & GFS2_DIF_EXHASH) {
 727                 struct gfs2_leaf *leaf;
 728                 unsigned hsize = 1 << ip->i_depth;
 729                 unsigned index;
 730                 u64 ln;
 731                 if (hsize * sizeof(u64) != i_size_read(inode)) {
 732                         gfs2_consist_inode(ip);
 733                         return ERR_PTR(-EIO);
 734                 }
 735
 736                 index = name->hash >> (32 - ip->i_depth);
 737                 error = get_first_leaf(ip, index, &bh);
 738                 if (error)
 739                         return ERR_PTR(error);
 740                 do {
 741                         dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
 742                                                 scan, name, NULL);
 743                         if (dent)
 744                                 goto got_dent;
 745                         leaf = (struct gfs2_leaf *)bh->b_data;
 746                         ln = be64_to_cpu(leaf->lf_next);
 747                         brelse(bh);
 748                         if (!ln)
 749                                 break;
 750
 751                         error = get_leaf(ip, ln, &bh);
 752                 } while(!error);
 753
 754                 return error ? ERR_PTR(error) : NULL;
 755         }
 756
 757
 758         error = gfs2_meta_inode_buffer(ip, &bh);
 759         if (error)
 760                 return ERR_PTR(error);
 761         dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size, scan, name, NULL);
 762 got_dent:
 763         if (unlikely(dent == NULL || IS_ERR(dent))) {
 764                 brelse(bh);
 765                 bh = NULL;
 766         }
 767         *pbh = bh;
 768         return dent;
 769 }
 770
 771 static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh, u16 depth)
 772 {
 773         struct gfs2_inode *ip = GFS2_I(inode);
 774         unsigned int n = 1;
 775         u64 bn;
 776         int error;
 777         struct buffer_head *bh;
 778         struct gfs2_leaf *leaf;
 779         struct gfs2_dirent *dent;
 780         struct qstr name = { .name = "", .len = 0, .hash = 0 };
 781
 782         error = gfs2_alloc_block(ip, &bn, &n);
 783         if (error)
 784                 return NULL;
 785         bh = gfs2_meta_new(ip->i_gl, bn);
 786         if (!bh)
 787                 return NULL;
 788
 789         gfs2_trans_add_unrevoke(GFS2_SB(inode), bn, 1);
 790         gfs2_trans_add_bh(ip->i_gl, bh, 1);
 791         gfs2_metatype_set(bh, GFS2_METATYPE_LF, GFS2_FORMAT_LF);
 792         leaf = (struct gfs2_leaf *)bh->b_data;
 793         leaf->lf_depth = cpu_to_be16(depth);
 794         leaf->lf_entries = 0;
 795         leaf->lf_dirent_format = cpu_to_be32(GFS2_FORMAT_DE);
 796         leaf->lf_next = 0;
 797         memset(leaf->lf_reserved, 0, sizeof(leaf->lf_reserved));
 798         dent = (struct gfs2_dirent *)(leaf+1);
 799         gfs2_qstr2dirent(&name, bh->b_size - sizeof(struct gfs2_leaf), dent);
 800         *pbh = bh;
 801         return leaf;
 802 }
 803
 804 /**
 805  * dir_make_exhash - Convert a stuffed directory into an ExHash directory
 806  * @dip: The GFS2 inode
 807  *
 808  * Returns: 0 on success, error code otherwise
 809  */
 810
 811 static int dir_make_exhash(struct inode *inode)
 812 {
 813         struct gfs2_inode *dip = GFS2_I(inode);
 814         struct gfs2_sbd *sdp = GFS2_SB(inode);
 815         struct gfs2_dirent *dent;
 816         struct qstr args;
 817         struct buffer_head *bh, *dibh;
 818         struct gfs2_leaf *leaf;
 819         int y;
 820         u32 x;
 821         __be64 *lp;
 822         u64 bn;
 823         int error;
 824
 825         error = gfs2_meta_inode_buffer(dip, &dibh);
 826         if (error)
 827                 return error;
 828
 829         /*  Turn over a new leaf  */
 830
 831         leaf = new_leaf(inode, &bh, 0);
 832         if (!leaf)
 833                 return -ENOSPC;
 834         bn = bh->b_blocknr;
 835
 836         gfs2_assert(sdp, dip->i_entries < (1 << 16));
 837         leaf->lf_entries = cpu_to_be16(dip->i_entries);
 838
 839         /*  Copy dirents  */
 840
 841         gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_leaf), dibh,
 842                              sizeof(struct gfs2_dinode));
 843
 844         /*  Find last entry  */
 845
 846         x = 0;
 847         args.len = bh->b_size - sizeof(struct gfs2_dinode) +
 848                    sizeof(struct gfs2_leaf);
 849         args.name = bh->b_data;
 850         dent = gfs2_dirent_scan(&dip->i_inode, bh->b_data, bh->b_size,
 851                                 gfs2_dirent_last, &args, NULL);
 852         if (!dent) {
 853                 brelse(bh);
 854                 brelse(dibh);
 855                 return -EIO;
 856         }
 857         if (IS_ERR(dent)) {
 858                 brelse(bh);
 859                 brelse(dibh);
 860                 return PTR_ERR(dent);
 861         }
 862
 863         /*  Adjust the last dirent's record length
 864            (Remember that dent still points to the last entry.)  */
 865
 866         dent->de_rec_len = cpu_to_be16(be16_to_cpu(dent->de_rec_len) +
 867                 sizeof(struct gfs2_dinode) -
 868                 sizeof(struct gfs2_leaf));
 869
 870         brelse(bh);
 871
 872         /*  We're done with the new leaf block, now setup the new
 873             hash table.  */
 874
 875         gfs2_trans_add_bh(dip->i_gl, dibh, 1);
 876         gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
 877
 878         lp = (__be64 *)(dibh->b_data + sizeof(struct gfs2_dinode));
 879
 880         for (x = sdp->sd_hash_ptrs; x--; lp++)
 881                 *lp = cpu_to_be64(bn);
 882
 883         i_size_write(inode, sdp->sd_sb.sb_bsize / 2);
 884         gfs2_add_inode_blocks(&dip->i_inode, 1);
 885         dip->i_diskflags |= GFS2_DIF_EXHASH;
 886
 887         for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;
 888         dip->i_depth = y;
 889
 890         gfs2_dinode_out(dip, dibh->b_data);
 891
 892         brelse(dibh);
 893
 894         return 0;
 895 }
 896
 897 /**
 898  * dir_split_leaf - Split a leaf block into two
 899  * @dip: The GFS2 inode
 900  * @index:
 901  * @leaf_no:
 902  *
 903  * Returns: 0 on success, error code on failure
 904  */
 905
 906 static int dir_split_leaf(struct inode *inode, const struct qstr *name)
 907 {
 908         struct gfs2_inode *dip = GFS2_I(inode);
 909         struct buffer_head *nbh, *obh, *dibh;
 910         struct gfs2_leaf *nleaf, *oleaf;
 911         struct gfs2_dirent *dent = NULL, *prev = NULL, *next = NULL, *new;
 912         u32 start, len, half_len, divider;
 913         u64 bn, leaf_no;
 914         __be64 *lp;
 915         u32 index;
 916         int x, moved = 0;
 917         int error;
 918
 919         index = name->hash >> (32 - dip->i_depth);
 920         error = get_leaf_nr(dip, index, &leaf_no);
 921         if (error)
 922                 return error;
 923
 924         /*  Get the old leaf block  */
 925         error = get_leaf(dip, leaf_no, &obh);
 926         if (error)
 927                 return error;
 928
 929         oleaf = (struct gfs2_leaf *)obh->b_data;
 930         if (dip->i_depth == be16_to_cpu(oleaf->lf_depth)) {
 931                 brelse(obh);
 932                 return 1; /* can't split */
 933         }
 934
 935         gfs2_trans_add_bh(dip->i_gl, obh, 1);
 936
 937         nleaf = new_leaf(inode, &nbh, be16_to_cpu(oleaf->lf_depth) + 1);
 938         if (!nleaf) {
 939                 brelse(obh);
 940                 return -ENOSPC;
 941         }
 942         bn = nbh->b_blocknr;
 943
 944         /*  Compute the start and len of leaf pointers in the hash table.  */
 945         len = 1 << (dip->i_depth - be16_to_cpu(oleaf->lf_depth));
 946         half_len = len >> 1;
 947         if (!half_len) {
 948                 printk(KERN_WARNING "i_depth %u lf_depth %u index %u\n", dip->i_depth, be16_to_cpu(oleaf->lf_depth), index);
 949                 gfs2_consist_inode(dip);
 950                 error = -EIO;
 951                 goto fail_brelse;
 952         }
 953
 954         start = (index & ~(len - 1));
 955
 956         /* Change the pointers.
 957            Don't bother distinguishing stuffed from non-stuffed.
 958            This code is complicated enough already. */
 959         lp = kmalloc(half_len * sizeof(__be64), GFP_NOFS);
 960         if (!lp) {
 961                 error = -ENOMEM;
 962                 goto fail_brelse;
 963         }
 964
 965         /*  Change the pointers  */
 966         for (x = 0; x < half_len; x++)
 967                 lp[x] = cpu_to_be64(bn);
 968
 969         error = gfs2_dir_write_data(dip, (char *)lp, start * sizeof(u64),
 970                                     half_len * sizeof(u64));
 971         if (error != half_len * sizeof(u64)) {
 972                 if (error >= 0)
 973                         error = -EIO;
 974                 goto fail_lpfree;
 975         }
 976
 977         kfree(lp);
 978
 979         /*  Compute the divider  */
 980         divider = (start + half_len) << (32 - dip->i_depth);
 981
 982         /*  Copy the entries  */
 983         dent = (struct gfs2_dirent *)(obh->b_data + sizeof(struct gfs2_leaf));
 984
 985         do {
 986                 next = dent;
 987                 if (dirent_next(dip, obh, &next))
 988                         next = NULL;
 989
 990                 if (!gfs2_dirent_sentinel(dent) &&
 991                     be32_to_cpu(dent->de_hash) < divider) {
 992                         struct qstr str;
 993                         str.name = (char*)(dent+1);
 994                         str.len = be16_to_cpu(dent->de_name_len);
 995                         str.hash = be32_to_cpu(dent->de_hash);
 996                         new = gfs2_dirent_alloc(inode, nbh, &str);
 997                         if (IS_ERR(new)) {
 998                                 error = PTR_ERR(new);
 999                                 break;
1000                         }
1001
1002                         new->de_inum = dent->de_inum; /* No endian worries */
1003                         new->de_type = dent->de_type; /* No endian worries */
1004                         be16_add_cpu(&nleaf->lf_entries, 1);
1005
1006                         dirent_del(dip, obh, prev, dent);
1007
1008                         if (!oleaf->lf_entries)
1009                                 gfs2_consist_inode(dip);
1010                         be16_add_cpu(&oleaf->lf_entries, -1);
1011
1012                         if (!prev)
1013                                 prev = dent;
1014
1015                         moved = 1;
1016                 } else {
1017                         prev = dent;
1018                 }
1019                 dent = next;
1020         } while (dent);
1021
1022         oleaf->lf_depth = nleaf->lf_depth;
1023
1024         error = gfs2_meta_inode_buffer(dip, &dibh);
1025         if (!gfs2_assert_withdraw(GFS2_SB(&dip->i_inode), !error)) {
1026                 gfs2_trans_add_bh(dip->i_gl, dibh, 1);
1027                 gfs2_add_inode_blocks(&dip->i_inode, 1);
1028                 gfs2_dinode_out(dip, dibh->b_data);
1029                 brelse(dibh);
1030         }
1031
1032         brelse(obh);
1033         brelse(nbh);
1034
1035         return error;
1036
1037 fail_lpfree:
1038         kfree(lp);
1039
1040 fail_brelse:
1041         brelse(obh);
1042         brelse(nbh);
1043         return error;
1044 }
1045
1046 /**
1047  * dir_double_exhash - Double size of ExHash table
1048  * @dip: The GFS2 dinode
1049  *
1050  * Returns: 0 on success, error code on failure
1051  */
1052
1053 static int dir_double_exhash(struct gfs2_inode *dip)
1054 {
1055         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
1056         struct buffer_head *dibh;
1057         u32 hsize;
1058         u64 *buf;
1059         u64 *from, *to;
1060         u64 block;
1061         u64 disksize = i_size_read(&dip->i_inode);
1062         int x;
1063         int error = 0;
1064
1065         hsize = 1 << dip->i_depth;
1066         if (hsize * sizeof(u64) != disksize) {
1067                 gfs2_consist_inode(dip);
1068                 return -EIO;
1069         }
1070
1071         /*  Allocate both the "from" and "to" buffers in one big chunk  */
1072
1073         buf = kcalloc(3, sdp->sd_hash_bsize, GFP_NOFS);
1074         if (!buf)
1075                 return -ENOMEM;
1076
1077         for (block = disksize >> sdp->sd_hash_bsize_shift; block--;) {
1078                 error = gfs2_dir_read_data(dip, (char *)buf,
1079                                             block * sdp->sd_hash_bsize,
1080                                             sdp->sd_hash_bsize, 1);
1081                 if (error != sdp->sd_hash_bsize) {
1082                         if (error >= 0)
1083                                 error = -EIO;
1084                         goto fail;
1085                 }
1086
1087                 from = buf;
1088                 to = (u64 *)((char *)buf + sdp->sd_hash_bsize);
1089
1090                 for (x = sdp->sd_hash_ptrs; x--; from++) {
1091                         *to++ = *from;  /*  No endianess worries  */
1092                         *to++ = *from;
1093                 }
1094
1095                 error = gfs2_dir_write_data(dip,
1096                                              (char *)buf + sdp->sd_hash_bsize,
1097                                              block * sdp->sd_sb.sb_bsize,
1098                                              sdp->sd_sb.sb_bsize);
1099                 if (error != sdp->sd_sb.sb_bsize) {
1100                         if (error >= 0)
1101                                 error = -EIO;
1102                         goto fail;
1103                 }
1104         }
1105
1106         kfree(buf);
1107
1108         error = gfs2_meta_inode_buffer(dip, &dibh);
1109         if (!gfs2_assert_withdraw(sdp, !error)) {
1110                 dip->i_depth++;
1111                 gfs2_dinode_out(dip, dibh->b_data);
1112                 brelse(dibh);
1113         }
1114
1115         return error;
1116
1117 fail:
1118         kfree(buf);
1119         return error;
1120 }
1121
1122 /**
1123  * compare_dents - compare directory entries by hash value
1124  * @a: first dent
1125  * @b: second dent
1126  *
1127  * When comparing the hash entries of @a to @b:
1128  *   gt: returns 1
1129  *   lt: returns -1
1130  *   eq: returns 0
1131  */
1132
1133 static int compare_dents(const void *a, const void *b)
1134 {
1135         const struct gfs2_dirent *dent_a, *dent_b;
1136         u32 hash_a, hash_b;
1137         int ret = 0;
1138
1139         dent_a = *(const struct gfs2_dirent **)a;
1140         hash_a = be32_to_cpu(dent_a->de_hash);
1141
1142         dent_b = *(const struct gfs2_dirent **)b;
1143         hash_b = be32_to_cpu(dent_b->de_hash);
1144
1145         if (hash_a > hash_b)
1146                 ret = 1;
1147         else if (hash_a < hash_b)
1148                 ret = -1;
1149         else {
1150                 unsigned int len_a = be16_to_cpu(dent_a->de_name_len);
1151                 unsigned int len_b = be16_to_cpu(dent_b->de_name_len);
1152
1153                 if (len_a > len_b)
1154                         ret = 1;
1155                 else if (len_a < len_b)
1156                         ret = -1;
1157                 else
1158                         ret = memcmp(dent_a + 1, dent_b + 1, len_a);
1159         }
1160
1161         return ret;
1162 }
1163
1164 /**
1165  * do_filldir_main - read out directory entries
1166  * @dip: The GFS2 inode
1167  * @offset: The offset in the file to read from
1168  * @opaque: opaque data to pass to filldir
1169  * @filldir: The function to pass entries to
1170  * @darr: an array of struct gfs2_dirent pointers to read
1171  * @entries: the number of entries in darr
1172  * @copied: pointer to int that's non-zero if a entry has been copied out
1173  *
1174  * Jump through some hoops to make sure that if there are hash collsions,
1175  * they are read out at the beginning of a buffer.  We want to minimize
1176  * the possibility that they will fall into different readdir buffers or
1177  * that someone will want to seek to that location.
1178  *
1179  * Returns: errno, >0 on exception from filldir
1180  */
1181
1182 static int do_filldir_main(struct gfs2_inode *dip, u64 *offset,
1183                            void *opaque, filldir_t filldir,
1184                            const struct gfs2_dirent **darr, u32 entries,
1185                            int *copied)
1186 {
1187         const struct gfs2_dirent *dent, *dent_next;
1188         u64 off, off_next;
1189         unsigned int x, y;
1190         int run = 0;
1191         int error = 0;
1192
1193         sort(darr, entries, sizeof(struct gfs2_dirent *), compare_dents, NULL);
1194
1195         dent_next = darr[0];
1196         off_next = be32_to_cpu(dent_next->de_hash);
1197         off_next = gfs2_disk_hash2offset(off_next);
1198
1199         for (x = 0, y = 1; x < entries; x++, y++) {
1200                 dent = dent_next;
1201                 off = off_next;
1202
1203                 if (y < entries) {
1204                         dent_next = darr[y];
1205                         off_next = be32_to_cpu(dent_next->de_hash);
1206                         off_next = gfs2_disk_hash2offset(off_next);
1207
1208                         if (off < *offset)
1209                                 continue;
1210                         *offset = off;
1211
1212                         if (off_next == off) {
1213                                 if (*copied && !run)
1214                                         return 1;
1215                                 run = 1;
1216                         } else
1217                                 run = 0;
1218                 } else {
1219                         if (off < *offset)
1220                                 continue;
1221                         *offset = off;
1222                 }
1223
1224                 error = filldir(opaque, (const char *)(dent + 1),
1225                                 be16_to_cpu(dent->de_name_len),
1226                                 off, be64_to_cpu(dent->de_inum.no_addr),
1227                                 be16_to_cpu(dent->de_type));
1228                 if (error)
1229                         return 1;
1230
1231                 *copied = 1;
1232         }
1233
1234         /* Increment the *offset by one, so the next time we come into the
1235            do_filldir fxn, we get the next entry instead of the last one in the
1236            current leaf */
1237
1238         (*offset)++;
1239
1240         return 0;
1241 }
1242
1243 static void *gfs2_alloc_sort_buffer(unsigned size)
1244 {
1245         void *ptr = NULL;
1246
1247         if (size < KMALLOC_MAX_SIZE)
1248                 ptr = kmalloc(size, GFP_NOFS | __GFP_NOWARN);
1249         if (!ptr)
1250                 ptr = __vmalloc(size, GFP_NOFS, PAGE_KERNEL);
1251         return ptr;
1252 }
1253
1254 static void gfs2_free_sort_buffer(void *ptr)
1255 {
1256         if (is_vmalloc_addr(ptr))
1257                 vfree(ptr);
1258         else
1259                 kfree(ptr);
1260 }
1261
1262 static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
1263                               filldir_t filldir, int *copied, unsigned *depth,
1264                               u64 leaf_no)
1265 {
1266         struct gfs2_inode *ip = GFS2_I(inode);
1267         struct gfs2_sbd *sdp = GFS2_SB(inode);
1268         struct buffer_head *bh;
1269         struct gfs2_leaf *lf;
1270         unsigned entries = 0, entries2 = 0;
1271         unsigned leaves = 0;
1272         const struct gfs2_dirent **darr, *dent;
1273         struct dirent_gather g;
1274         struct buffer_head **larr;
1275         int leaf = 0;
1276         int error, i;
1277         u64 lfn = leaf_no;
1278
1279         do {
1280                 error = get_leaf(ip, lfn, &bh);
1281                 if (error)
1282                         goto out;
1283                 lf = (struct gfs2_leaf *)bh->b_data;
1284                 if (leaves == 0)
1285                         *depth = be16_to_cpu(lf->lf_depth);
1286                 entries += be16_to_cpu(lf->lf_entries);
1287                 leaves++;
1288                 lfn = be64_to_cpu(lf->lf_next);
1289                 brelse(bh);
1290         } while(lfn);
1291
1292         if (!entries)
1293                 return 0;
1294
1295         error = -ENOMEM;
1296         /*
1297          * The extra 99 entries are not normally used, but are a buffer
1298          * zone in case the number of entries in the leaf is corrupt.
1299          * 99 is the maximum number of entries that can fit in a single
1300          * leaf block.
1301          */
1302         larr = gfs2_alloc_sort_buffer((leaves + entries + 99) * sizeof(void *));
1303         if (!larr)
1304                 goto out;
1305         darr = (const struct gfs2_dirent **)(larr + leaves);
1306         g.pdent = darr;
1307         g.offset = 0;
1308         lfn = leaf_no;
1309
1310         do {
1311                 error = get_leaf(ip, lfn, &bh);
1312                 if (error)
1313                         goto out_free;
1314                 lf = (struct gfs2_leaf *)bh->b_data;
1315                 lfn = be64_to_cpu(lf->lf_next);
1316                 if (lf->lf_entries) {
1317                         entries2 += be16_to_cpu(lf->lf_entries);
1318                         dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
1319                                                 gfs2_dirent_gather, NULL, &g);
1320                         error = PTR_ERR(dent);
1321                         if (IS_ERR(dent))
1322                                 goto out_free;
1323                         if (entries2 != g.offset) {
1324                                 fs_warn(sdp, "Number of entries corrupt in dir "
1325                                                 "leaf %llu, entries2 (%u) != "
1326                                                 "g.offset (%u)\n",
1327                                         (unsigned long long)bh->b_blocknr,
1328                                         entries2, g.offset);
1329
1330                                 error = -EIO;
1331                                 goto out_free;
1332                         }
1333                         error = 0;
1334                         larr[leaf++] = bh;
1335                 } else {
1336                         brelse(bh);
1337                 }
1338         } while(lfn);
1339
1340         BUG_ON(entries2 != entries);
1341         error = do_filldir_main(ip, offset, opaque, filldir, darr,
1342                                 entries, copied);
1343 out_free:
1344         for(i = 0; i < leaf; i++)
1345                 brelse(larr[i]);
1346         gfs2_free_sort_buffer(larr);
1347 out:
1348         return error;
1349 }
1350
1351 /**
1352  * dir_e_read - Reads the entries from a directory into a filldir buffer
1353  * @dip: dinode pointer
1354  * @offset: the hash of the last entry read shifted to the right once
1355  * @opaque: buffer for the filldir function to fill
1356  * @filldir: points to the filldir function to use
1357  *
1358  * Returns: errno
1359  */
1360
1361 static int dir_e_read(struct inode *inode, u64 *offset, void *opaque,
1362                       filldir_t filldir)
1363 {
1364         struct gfs2_inode *dip = GFS2_I(inode);
1365         struct gfs2_sbd *sdp = GFS2_SB(inode);
1366         u32 hsize, len = 0;
1367         u32 ht_offset, lp_offset, ht_offset_cur = -1;
1368         u32 hash, index;
1369         __be64 *lp;
1370         int copied = 0;
1371         int error = 0;
1372         unsigned depth = 0;
1373
1374         hsize = 1 << dip->i_depth;
1375         if (hsize * sizeof(u64) != i_size_read(inode)) {
1376                 gfs2_consist_inode(dip);
1377                 return -EIO;
1378         }
1379
1380         hash = gfs2_dir_offset2hash(*offset);
1381         index = hash >> (32 - dip->i_depth);
1382
1383         lp = kmalloc(sdp->sd_hash_bsize, GFP_NOFS);
1384         if (!lp)
1385                 return -ENOMEM;
1386
1387         while (index < hsize) {
1388                 lp_offset = index & (sdp->sd_hash_ptrs - 1);
1389                 ht_offset = index - lp_offset;
1390
1391                 if (ht_offset_cur != ht_offset) {
1392                         error = gfs2_dir_read_data(dip, (char *)lp,
1393                                                 ht_offset * sizeof(__be64),
1394                                                 sdp->sd_hash_bsize, 1);
1395                         if (error != sdp->sd_hash_bsize) {
1396                                 if (error >= 0)
1397                                         error = -EIO;
1398                                 goto out;
1399                         }
1400                         ht_offset_cur = ht_offset;
1401                 }
1402
1403                 error = gfs2_dir_read_leaf(inode, offset, opaque, filldir,
1404                                            &copied, &depth,
1405                                            be64_to_cpu(lp[lp_offset]));
1406                 if (error)
1407                         break;
1408
1409                 len = 1 << (dip->i_depth - depth);
1410                 index = (index & ~(len - 1)) + len;
1411         }
1412
1413 out:
1414         kfree(lp);
1415         if (error > 0)
1416                 error = 0;
1417         return error;
1418 }
1419
1420 int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
1421                   filldir_t filldir)
1422 {
1423         struct gfs2_inode *dip = GFS2_I(inode);
1424         struct gfs2_sbd *sdp = GFS2_SB(inode);
1425         struct dirent_gather g;
1426         const struct gfs2_dirent **darr, *dent;
1427         struct buffer_head *dibh;
1428         int copied = 0;
1429         int error;
1430
1431         if (!dip->i_entries)
1432                 return 0;
1433
1434         if (dip->i_diskflags & GFS2_DIF_EXHASH)
1435                 return dir_e_read(inode, offset, opaque, filldir);
1436
1437         if (!gfs2_is_stuffed(dip)) {
1438                 gfs2_consist_inode(dip);
1439                 return -EIO;
1440         }
1441
1442         error = gfs2_meta_inode_buffer(dip, &dibh);
1443         if (error)
1444                 return error;
1445
1446         error = -ENOMEM;
1447         /* 96 is max number of dirents which can be stuffed into an inode */
1448         darr = kmalloc(96 * sizeof(struct gfs2_dirent *), GFP_NOFS);
1449         if (darr) {
1450                 g.pdent = darr;
1451                 g.offset = 0;
1452                 dent = gfs2_dirent_scan(inode, dibh->b_data, dibh->b_size,
1453                                         gfs2_dirent_gather, NULL, &g);
1454                 if (IS_ERR(dent)) {
1455                         error = PTR_ERR(dent);
1456                         goto out;
1457                 }
1458                 if (dip->i_entries != g.offset) {
1459                         fs_warn(sdp, "Number of entries corrupt in dir %llu, "
1460                                 "ip->i_entries (%u) != g.offset (%u)\n",
1461                                 (unsigned long long)dip->i_no_addr,
1462                                 dip->i_entries,
1463                                 g.offset);
1464                         error = -EIO;
1465                         goto out;
1466                 }
1467                 error = do_filldir_main(dip, offset, opaque, filldir, darr,
1468                                         dip->i_entries, &copied);
1469 out:
1470                 kfree(darr);
1471         }
1472
1473         if (error > 0)
1474                 error = 0;
1475
1476         brelse(dibh);
1477
1478         return error;
1479 }
1480
1481 /**
1482  * gfs2_dir_search - Search a directory
1483  * @dip: The GFS2 inode
1484  * @filename:
1485  * @inode:
1486  *
1487  * This routine searches a directory for a file or another directory.
1488  * Assumes a glock is held on dip.
1489  *
1490  * Returns: errno
1491  */
1492
1493 struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name)
1494 {
1495         struct buffer_head *bh;
1496         struct gfs2_dirent *dent;
1497         struct inode *inode;
1498
1499         dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
1500         if (dent) {
1501                 if (IS_ERR(dent))
1502                         return ERR_CAST(dent);
1503                 inode = gfs2_inode_lookup(dir->i_sb,
1504                                 be16_to_cpu(dent->de_type),
1505                                 be64_to_cpu(dent->de_inum.no_addr),
1506                                 be64_to_cpu(dent->de_inum.no_formal_ino), 0);
1507                 brelse(bh);
1508                 return inode;
1509         }
1510         return ERR_PTR(-ENOENT);
1511 }
1512
1513 int gfs2_dir_check(struct inode *dir, const struct qstr *name,
1514                    const struct gfs2_inode *ip)
1515 {
1516         struct buffer_head *bh;
1517         struct gfs2_dirent *dent;
1518         int ret = -ENOENT;
1519
1520         dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
1521         if (dent) {
1522                 if (IS_ERR(dent))
1523                         return PTR_ERR(dent);
1524                 if (ip) {
1525                         if (be64_to_cpu(dent->de_inum.no_addr) != ip->i_no_addr)
1526                                 goto out;
1527                         if (be64_to_cpu(dent->de_inum.no_formal_ino) !=
1528                             ip->i_no_formal_ino)
1529                                 goto out;
1530                         if (unlikely(IF2DT(ip->i_inode.i_mode) !=
1531                             be16_to_cpu(dent->de_type))) {
1532                                 gfs2_consist_inode(GFS2_I(dir));
1533                                 ret = -EIO;
1534                                 goto out;
1535                         }
1536                 }
1537                 ret = 0;
1538 out:
1539                 brelse(bh);
1540         }
1541         return ret;
1542 }
1543
1544 static int dir_new_leaf(struct inode *inode, const struct qstr *name)
1545 {
1546         struct buffer_head *bh, *obh;
1547         struct gfs2_inode *ip = GFS2_I(inode);
1548         struct gfs2_leaf *leaf, *oleaf;
1549         int error;
1550         u32 index;
1551         u64 bn;
1552
1553         index = name->hash >> (32 - ip->i_depth);
1554         error = get_first_leaf(ip, index, &obh);
1555         if (error)
1556                 return error;
1557         do {
1558                 oleaf = (struct gfs2_leaf *)obh->b_data;
1559                 bn = be64_to_cpu(oleaf->lf_next);
1560                 if (!bn)
1561                         break;
1562                 brelse(obh);
1563                 error = get_leaf(ip, bn, &obh);
1564                 if (error)
1565                         return error;
1566         } while(1);
1567
1568         gfs2_trans_add_bh(ip->i_gl, obh, 1);
1569
1570         leaf = new_leaf(inode, &bh, be16_to_cpu(oleaf->lf_depth));
1571         if (!leaf) {
1572                 brelse(obh);
1573                 return -ENOSPC;
1574         }
1575         oleaf->lf_next = cpu_to_be64(bh->b_blocknr);
1576         brelse(bh);
1577         brelse(obh);
1578
1579         error = gfs2_meta_inode_buffer(ip, &bh);
1580         if (error)
1581                 return error;
1582         gfs2_trans_add_bh(ip->i_gl, bh, 1);
1583         gfs2_add_inode_blocks(&ip->i_inode, 1);
1584         gfs2_dinode_out(ip, bh->b_data);
1585         brelse(bh);
1586         return 0;
1587 }
1588
1589 /**
1590  * gfs2_dir_add - Add new filename into directory
1591  * @dip: The GFS2 inode
1592  * @filename: The new name
1593  * @inode: The inode number of the entry
1594  * @type: The type of the entry
1595  *
1596  * Returns: 0 on success, error code on failure
1597  */
1598
1599 int gfs2_dir_add(struct inode *inode, const struct qstr *name,
1600                  const struct gfs2_inode *nip)
1601 {
1602         struct gfs2_inode *ip = GFS2_I(inode);
1603         struct buffer_head *bh;
1604         struct gfs2_dirent *dent;
1605         struct gfs2_leaf *leaf;
1606         int error;
1607
1608         while(1) {
1609                 dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space,
1610                                           &bh);
1611                 if (dent) {
1612                         if (IS_ERR(dent))
1613                                 return PTR_ERR(dent);
1614                         dent = gfs2_init_dirent(inode, dent, name, bh);
1615                         gfs2_inum_out(nip, dent);
1616                         dent->de_type = cpu_to_be16(IF2DT(nip->i_inode.i_mode));
1617                         if (ip->i_diskflags & GFS2_DIF_EXHASH) {
1618                                 leaf = (struct gfs2_leaf *)bh->b_data;
1619                                 be16_add_cpu(&leaf->lf_entries, 1);
1620                         }
1621                         brelse(bh);
1622                         error = gfs2_meta_inode_buffer(ip, &bh);
1623                         if (error)
1624                                 break;
1625                         gfs2_trans_add_bh(ip->i_gl, bh, 1);
1626                         ip->i_entries++;
1627                         ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
1628                         if (S_ISDIR(nip->i_inode.i_mode))
1629                                 inc_nlink(&ip->i_inode);
1630                         gfs2_dinode_out(ip, bh->b_data);
1631                         brelse(bh);
1632                         error = 0;
1633                         break;
1634                 }
1635                 if (!(ip->i_diskflags & GFS2_DIF_EXHASH)) {
1636                         error = dir_make_exhash(inode);
1637                         if (error)
1638                                 break;
1639                         continue;
1640                 }
1641                 error = dir_split_leaf(inode, name);
1642                 if (error == 0)
1643                         continue;
1644                 if (error < 0)
1645                         break;
1646                 if (ip->i_depth < GFS2_DIR_MAX_DEPTH) {
1647                         error = dir_double_exhash(ip);
1648                         if (error)
1649                                 break;
1650                         error = dir_split_leaf(inode, name);
1651                         if (error < 0)
1652                                 break;
1653                         if (error == 0)
1654                                 continue;
1655                 }
1656                 error = dir_new_leaf(inode, name);
1657                 if (!error)
1658                         continue;
1659                 error = -ENOSPC;
1660                 break;
1661         }
1662         return error;
1663 }
1664
1665
1666 /**
1667  * gfs2_dir_del - Delete a directory entry
1668  * @dip: The GFS2 inode
1669  * @filename: The filename
1670  *
1671  * Returns: 0 on success, error code on failure
1672  */
1673
1674 int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry)
1675 {
1676         const struct qstr *name = &dentry->d_name;
1677         struct gfs2_dirent *dent, *prev = NULL;
1678         struct buffer_head *bh;
1679         int error;
1680
1681         /* Returns _either_ the entry (if its first in block) or the
1682            previous entry otherwise */
1683         dent = gfs2_dirent_search(&dip->i_inode, name, gfs2_dirent_prev, &bh);
1684         if (!dent) {
1685                 gfs2_consist_inode(dip);
1686                 return -EIO;
1687         }
1688         if (IS_ERR(dent)) {
1689                 gfs2_consist_inode(dip);
1690                 return PTR_ERR(dent);
1691         }
1692         /* If not first in block, adjust pointers accordingly */
1693         if (gfs2_dirent_find(dent, name, NULL) == 0) {
1694                 prev = dent;
1695                 dent = (struct gfs2_dirent *)((char *)dent + be16_to_cpu(prev->de_rec_len));
1696         }
1697
1698         dirent_del(dip, bh, prev, dent);
1699         if (dip->i_diskflags & GFS2_DIF_EXHASH) {
1700                 struct gfs2_leaf *leaf = (struct gfs2_leaf *)bh->b_data;
1701                 u16 entries = be16_to_cpu(leaf->lf_entries);
1702                 if (!entries)
1703                         gfs2_consist_inode(dip);
1704                 leaf->lf_entries = cpu_to_be16(--entries);
1705         }
1706         brelse(bh);
1707
1708         error = gfs2_meta_inode_buffer(dip, &bh);
1709         if (error)
1710                 return error;
1711
1712         if (!dip->i_entries)
1713                 gfs2_consist_inode(dip);
1714         gfs2_trans_add_bh(dip->i_gl, bh, 1);
1715         dip->i_entries--;
1716         dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;
1717         if (S_ISDIR(dentry->d_inode->i_mode))
1718                 drop_nlink(&dip->i_inode);
1719         gfs2_dinode_out(dip, bh->b_data);
1720         brelse(bh);
1721         mark_inode_dirty(&dip->i_inode);
1722
1723         return error;
1724 }
1725
1726 /**
1727  * gfs2_dir_mvino - Change inode number of directory entry
1728  * @dip: The GFS2 inode
1729  * @filename:
1730  * @new_inode:
1731  *
1732  * This routine changes the inode number of a directory entry.  It's used
1733  * by rename to change ".." when a directory is moved.
1734  * Assumes a glock is held on dvp.
1735  *
1736  * Returns: errno
1737  */
1738
1739 int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
1740                    const struct gfs2_inode *nip, unsigned int new_type)
1741 {
1742         struct buffer_head *bh;
1743         struct gfs2_dirent *dent;
1744         int error;
1745
1746         dent = gfs2_dirent_search(&dip->i_inode, filename, gfs2_dirent_find, &bh);
1747         if (!dent) {
1748                 gfs2_consist_inode(dip);
1749                 return -EIO;
1750         }
1751         if (IS_ERR(dent))
1752                 return PTR_ERR(dent);
1753
1754         gfs2_trans_add_bh(dip->i_gl, bh, 1);
1755         gfs2_inum_out(nip, dent);
1756         dent->de_type = cpu_to_be16(new_type);
1757
1758         if (dip->i_diskflags & GFS2_DIF_EXHASH) {
1759                 brelse(bh);
1760                 error = gfs2_meta_inode_buffer(dip, &bh);
1761                 if (error)
1762                         return error;
1763                 gfs2_trans_add_bh(dip->i_gl, bh, 1);
1764         }
1765
1766         dip->i_inode.i_mtime = dip->i_inode.i_ctime = CURRENT_TIME;
1767         gfs2_dinode_out(dip, bh->b_data);
1768         brelse(bh);
1769         return 0;
1770 }
1771
1772 /**
1773  * leaf_dealloc - Deallocate a directory leaf
1774  * @dip: the directory
1775  * @index: the hash table offset in the directory
1776  * @len: the number of pointers to this leaf
1777  * @leaf_no: the leaf number
1778  * @leaf_bh: buffer_head for the starting leaf
1779  * last_dealloc: 1 if this is the final dealloc for the leaf, else 0
1780  *
1781  * Returns: errno
1782  */
1783
1784 static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len,
1785                         u64 leaf_no, struct buffer_head *leaf_bh,
1786                         int last_dealloc)
1787 {
1788         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
1789         struct gfs2_leaf *tmp_leaf;
1790         struct gfs2_rgrp_list rlist;
1791         struct buffer_head *bh, *dibh;
1792         u64 blk, nblk;
1793         unsigned int rg_blocks = 0, l_blocks = 0;
1794         char *ht;
1795         unsigned int x, size = len * sizeof(u64);
1796         int error;
1797
1798         memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
1799
1800         ht = kzalloc(size, GFP_NOFS);
1801         if (!ht)
1802                 return -ENOMEM;
1803
1804         if (!gfs2_alloc_get(dip)) {
1805                 error = -ENOMEM;
1806                 goto out;
1807         }
1808
1809         error = gfs2_quota_hold(dip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
1810         if (error)
1811                 goto out_put;
1812
1813         error = gfs2_rindex_hold(sdp, &dip->i_alloc->al_ri_gh);
1814         if (error)
1815                 goto out_qs;
1816
1817         /*  Count the number of leaves  */
1818         bh = leaf_bh;
1819
1820         for (blk = leaf_no; blk; blk = nblk) {
1821                 if (blk != leaf_no) {
1822                         error = get_leaf(dip, blk, &bh);
1823                         if (error)
1824                                 goto out_rlist;
1825                 }
1826                 tmp_leaf = (struct gfs2_leaf *)bh->b_data;
1827                 nblk = be64_to_cpu(tmp_leaf->lf_next);
1828                 if (blk != leaf_no)
1829                         brelse(bh);
1830
1831                 gfs2_rlist_add(sdp, &rlist, blk);
1832                 l_blocks++;
1833         }
1834
1835         gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE);
1836
1837         for (x = 0; x < rlist.rl_rgrps; x++) {
1838                 struct gfs2_rgrpd *rgd;
1839                 rgd = rlist.rl_ghs[x].gh_gl->gl_object;
1840                 rg_blocks += rgd->rd_length;
1841         }
1842
1843         error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
1844         if (error)
1845                 goto out_rlist;
1846
1847         error = gfs2_trans_begin(sdp,
1848                         rg_blocks + (DIV_ROUND_UP(size, sdp->sd_jbsize) + 1) +
1849                         RES_DINODE + RES_STATFS + RES_QUOTA, l_blocks);
1850         if (error)
1851                 goto out_rg_gunlock;
1852
1853         bh = leaf_bh;
1854
1855         for (blk = leaf_no; blk; blk = nblk) {
1856                 if (blk != leaf_no) {
1857                         error = get_leaf(dip, blk, &bh);
1858                         if (error)
1859                                 goto out_end_trans;
1860                 }
1861                 tmp_leaf = (struct gfs2_leaf *)bh->b_data;
1862                 nblk = be64_to_cpu(tmp_leaf->lf_next);
1863                 if (blk != leaf_no)
1864                         brelse(bh);
1865
1866                 gfs2_free_meta(dip, blk, 1);
1867                 gfs2_add_inode_blocks(&dip->i_inode, -1);
1868         }
1869
1870         error = gfs2_dir_write_data(dip, ht, index * sizeof(u64), size);
1871         if (error != size) {
1872                 if (error >= 0)
1873                         error = -EIO;
1874                 goto out_end_trans;
1875         }
1876
1877         error = gfs2_meta_inode_buffer(dip, &dibh);
1878         if (error)
1879                 goto out_end_trans;
1880
1881         gfs2_trans_add_bh(dip->i_gl, dibh, 1);
1882         /* On the last dealloc, make this a regular file in case we crash.
1883            (We don't want to free these blocks a second time.)  */
1884         if (last_dealloc)
1885                 dip->i_inode.i_mode = S_IFREG;
1886         gfs2_dinode_out(dip, dibh->b_data);
1887         brelse(dibh);
1888
1889 out_end_trans:
1890         gfs2_trans_end(sdp);
1891 out_rg_gunlock:
1892         gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
1893 out_rlist:
1894         gfs2_rlist_free(&rlist);
1895         gfs2_glock_dq_uninit(&dip->i_alloc->al_ri_gh);
1896 out_qs:
1897         gfs2_quota_unhold(dip);
1898 out_put:
1899         gfs2_alloc_put(dip);
1900 out:
1901         kfree(ht);
1902         return error;
1903 }
1904
1905 /**
1906  * gfs2_dir_exhash_dealloc - free all the leaf blocks in a directory
1907  * @dip: the directory
1908  *
1909  * Dealloc all on-disk directory leaves to FREEMETA state
1910  * Change on-disk inode type to "regular file"
1911  *
1912  * Returns: errno
1913  */
1914
1915 int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip)
1916 {
1917         struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
1918         struct buffer_head *bh;
1919         struct gfs2_leaf *leaf;
1920         u32 hsize, len;
1921         u32 ht_offset, lp_offset, ht_offset_cur = -1;
1922         u32 index = 0, next_index;
1923         __be64 *lp;
1924         u64 leaf_no;
1925         int error = 0, last;
1926
1927         hsize = 1 << dip->i_depth;
1928         if (hsize * sizeof(u64) != i_size_read(&dip->i_inode)) {
1929                 gfs2_consist_inode(dip);
1930                 return -EIO;
1931         }
1932
1933         lp = kmalloc(sdp->sd_hash_bsize, GFP_NOFS);
1934         if (!lp)
1935                 return -ENOMEM;
1936
1937         while (index < hsize) {
1938                 lp_offset = index & (sdp->sd_hash_ptrs - 1);
1939                 ht_offset = index - lp_offset;
1940
1941                 if (ht_offset_cur != ht_offset) {
1942                         error = gfs2_dir_read_data(dip, (char *)lp,
1943                                                 ht_offset * sizeof(__be64),
1944                                                 sdp->sd_hash_bsize, 1);
1945                         if (error != sdp->sd_hash_bsize) {
1946                                 if (error >= 0)
1947                                         error = -EIO;
1948                                 goto out;
1949                         }
1950                         ht_offset_cur = ht_offset;
1951                 }
1952
1953                 leaf_no = be64_to_cpu(lp[lp_offset]);
1954                 if (leaf_no) {
1955                         error = get_leaf(dip, leaf_no, &bh);
1956                         if (error)
1957                                 goto out;
1958                         leaf = (struct gfs2_leaf *)bh->b_data;
1959                         len = 1 << (dip->i_depth - be16_to_cpu(leaf->lf_depth));
1960
1961                         next_index = (index & ~(len - 1)) + len;
1962                         last = ((next_index >= hsize) ? 1 : 0);
1963                         error = leaf_dealloc(dip, index, len, leaf_no, bh,
1964                                              last);
1965                         brelse(bh);
1966                         if (error)
1967                                 goto out;
1968                         index = next_index;
1969                 } else
1970                         index++;
1971         }
1972
1973         if (index != hsize) {
1974                 gfs2_consist_inode(dip);
1975                 error = -EIO;
1976         }
1977
1978 out:
1979         kfree(lp);
1980
1981         return error;
1982 }
1983
1984 /**
1985  * gfs2_diradd_alloc_required - find if adding entry will require an allocation
1986  * @ip: the file being written to
1987  * @filname: the filename that's going to be added
1988  *
1989  * Returns: 1 if alloc required, 0 if not, -ve on error
1990  */
1991
1992 int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name)
1993 {
1994         struct gfs2_dirent *dent;
1995         struct buffer_head *bh;
1996
1997         dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
1998         if (!dent) {
1999                 return 1;
2000         }
2001         if (IS_ERR(dent))
2002                 return PTR_ERR(dent);
2003         brelse(bh);
2004         return 0;
2005 }
2006