fs/quota/quota_tree.c

   1 /*
   2  *      vfsv0 quota IO operations on file
   3  */
   4
   5 #include <linux/errno.h>
   6 #include <linux/fs.h>
   7 #include <linux/mount.h>
   8 #include <linux/dqblk_v2.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/quotaops.h>
  14
  15 #include <asm/byteorder.h>
  16
  17 #include "quota_tree.h"
  18
  19 MODULE_AUTHOR("Jan Kara");
  20 MODULE_DESCRIPTION("Quota trie support");
  21 MODULE_LICENSE("GPL");
  22
  23 #define __QUOTA_QT_PARANOIA
  24
  25 static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth)
  26 {
  27         unsigned int epb = info->dqi_usable_bs >> 2;
  28         qid_t id = from_kqid(&init_user_ns, qid);
  29
  30         depth = info->dqi_qtree_depth - depth - 1;
  31         while (depth--)
  32                 id /= epb;
  33         return id % epb;
  34 }
  35
  36 /* Number of entries in one blocks */
  37 static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
  38 {
  39         return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
  40                / info->dqi_entry_size;
  41 }
  42
  43 static char *getdqbuf(size_t size)
  44 {
  45         char *buf = kmalloc(size, GFP_NOFS);
  46         if (!buf)
  47                 printk(KERN_WARNING
  48                        "VFS: Not enough memory for quota buffers.\n");
  49         return buf;
  50 }
  51
  52 static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
  53 {
  54         struct super_block *sb = info->dqi_sb;
  55
  56         memset(buf, 0, info->dqi_usable_bs);
  57         return sb->s_op->quota_read(sb, info->dqi_type, buf,
  58                info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
  59 }
  60
  61 static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
  62 {
  63         struct super_block *sb = info->dqi_sb;
  64         ssize_t ret;
  65
  66         ret = sb->s_op->quota_write(sb, info->dqi_type, buf,
  67                info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
  68         if (ret != info->dqi_usable_bs) {
  69                 quota_error(sb, "dquota write failed");
  70                 if (ret >= 0)
  71                         ret = -EIO;
  72         }
  73         return ret;
  74 }
  75
  76 /* Remove empty block from list and return it */
  77 static int get_free_dqblk(struct qtree_mem_dqinfo *info)
  78 {
  79         char *buf = getdqbuf(info->dqi_usable_bs);
  80         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
  81         int ret, blk;
  82
  83         if (!buf)
  84                 return -ENOMEM;
  85         if (info->dqi_free_blk) {
  86                 blk = info->dqi_free_blk;
  87                 ret = read_blk(info, blk, buf);
  88                 if (ret < 0)
  89                         goto out_buf;
  90                 info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
  91         }
  92         else {
  93                 memset(buf, 0, info->dqi_usable_bs);
  94                 /* Assure block allocation... */
  95                 ret = write_blk(info, info->dqi_blocks, buf);
  96                 if (ret < 0)
  97                         goto out_buf;
  98                 blk = info->dqi_blocks++;
  99         }
 100         mark_info_dirty(info->dqi_sb, info->dqi_type);
 101         ret = blk;
 102 out_buf:
 103         kfree(buf);
 104         return ret;
 105 }
 106
 107 /* Insert empty block to the list */
 108 static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
 109 {
 110         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 111         int err;
 112
 113         dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
 114         dh->dqdh_prev_free = cpu_to_le32(0);
 115         dh->dqdh_entries = cpu_to_le16(0);
 116         err = write_blk(info, blk, buf);
 117         if (err < 0)
 118                 return err;
 119         info->dqi_free_blk = blk;
 120         mark_info_dirty(info->dqi_sb, info->dqi_type);
 121         return 0;
 122 }
 123
 124 /* Remove given block from the list of blocks with free entries */
 125 static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
 126                                uint blk)
 127 {
 128         char *tmpbuf = getdqbuf(info->dqi_usable_bs);
 129         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 130         uint nextblk = le32_to_cpu(dh->dqdh_next_free);
 131         uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
 132         int err;
 133
 134         if (!tmpbuf)
 135                 return -ENOMEM;
 136         if (nextblk) {
 137                 err = read_blk(info, nextblk, tmpbuf);
 138                 if (err < 0)
 139                         goto out_buf;
 140                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
 141                                                         dh->dqdh_prev_free;
 142                 err = write_blk(info, nextblk, tmpbuf);
 143                 if (err < 0)
 144                         goto out_buf;
 145         }
 146         if (prevblk) {
 147                 err = read_blk(info, prevblk, tmpbuf);
 148                 if (err < 0)
 149                         goto out_buf;
 150                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
 151                                                         dh->dqdh_next_free;
 152                 err = write_blk(info, prevblk, tmpbuf);
 153                 if (err < 0)
 154                         goto out_buf;
 155         } else {
 156                 info->dqi_free_entry = nextblk;
 157                 mark_info_dirty(info->dqi_sb, info->dqi_type);
 158         }
 159         kfree(tmpbuf);
 160         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 161         /* No matter whether write succeeds block is out of list */
 162         if (write_blk(info, blk, buf) < 0)
 163                 quota_error(info->dqi_sb, "Can't write block (%u) "
 164                             "with free entries", blk);
 165         return 0;
 166 out_buf:
 167         kfree(tmpbuf);
 168         return err;
 169 }
 170
 171 /* Insert given block to the beginning of list with free entries */
 172 static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
 173                                uint blk)
 174 {
 175         char *tmpbuf = getdqbuf(info->dqi_usable_bs);
 176         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 177         int err;
 178
 179         if (!tmpbuf)
 180                 return -ENOMEM;
 181         dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
 182         dh->dqdh_prev_free = cpu_to_le32(0);
 183         err = write_blk(info, blk, buf);
 184         if (err < 0)
 185                 goto out_buf;
 186         if (info->dqi_free_entry) {
 187                 err = read_blk(info, info->dqi_free_entry, tmpbuf);
 188                 if (err < 0)
 189                         goto out_buf;
 190                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
 191                                                         cpu_to_le32(blk);
 192                 err = write_blk(info, info->dqi_free_entry, tmpbuf);
 193                 if (err < 0)
 194                         goto out_buf;
 195         }
 196         kfree(tmpbuf);
 197         info->dqi_free_entry = blk;
 198         mark_info_dirty(info->dqi_sb, info->dqi_type);
 199         return 0;
 200 out_buf:
 201         kfree(tmpbuf);
 202         return err;
 203 }
 204
 205 /* Is the entry in the block free? */
 206 int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
 207 {
 208         int i;
 209
 210         for (i = 0; i < info->dqi_entry_size; i++)
 211                 if (disk[i])
 212                         return 0;
 213         return 1;
 214 }
 215 EXPORT_SYMBOL(qtree_entry_unused);
 216
 217 /* Find space for dquot */
 218 static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
 219                               struct dquot *dquot, int *err)
 220 {
 221         uint blk, i;
 222         struct qt_disk_dqdbheader *dh;
 223         char *buf = getdqbuf(info->dqi_usable_bs);
 224         char *ddquot;
 225
 226         *err = 0;
 227         if (!buf) {
 228                 *err = -ENOMEM;
 229                 return 0;
 230         }
 231         dh = (struct qt_disk_dqdbheader *)buf;
 232         if (info->dqi_free_entry) {
 233                 blk = info->dqi_free_entry;
 234                 *err = read_blk(info, blk, buf);
 235                 if (*err < 0)
 236                         goto out_buf;
 237         } else {
 238                 blk = get_free_dqblk(info);
 239                 if ((int)blk < 0) {
 240                         *err = blk;
 241                         kfree(buf);
 242                         return 0;
 243                 }
 244                 memset(buf, 0, info->dqi_usable_bs);
 245                 /* This is enough as the block is already zeroed and the entry
 246                  * list is empty... */
 247                 info->dqi_free_entry = blk;
 248                 mark_info_dirty(dquot->dq_sb, dquot->dq_id.type);
 249         }
 250         /* Block will be full? */
 251         if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
 252                 *err = remove_free_dqentry(info, buf, blk);
 253                 if (*err < 0) {
 254                         quota_error(dquot->dq_sb, "Can't remove block (%u) "
 255                                     "from entry free list", blk);
 256                         goto out_buf;
 257                 }
 258         }
 259         le16_add_cpu(&dh->dqdh_entries, 1);
 260         /* Find free structure in block */
 261         ddquot = buf + sizeof(struct qt_disk_dqdbheader);
 262         for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
 263                 if (qtree_entry_unused(info, ddquot))
 264                         break;
 265                 ddquot += info->dqi_entry_size;
 266         }
 267 #ifdef __QUOTA_QT_PARANOIA
 268         if (i == qtree_dqstr_in_blk(info)) {
 269                 quota_error(dquot->dq_sb, "Data block full but it shouldn't");
 270                 *err = -EIO;
 271                 goto out_buf;
 272         }
 273 #endif
 274         *err = write_blk(info, blk, buf);
 275         if (*err < 0) {
 276                 quota_error(dquot->dq_sb, "Can't write quota data block %u",
 277                             blk);
 278                 goto out_buf;
 279         }
 280         dquot->dq_off = (blk << info->dqi_blocksize_bits) +
 281                         sizeof(struct qt_disk_dqdbheader) +
 282                         i * info->dqi_entry_size;
 283         kfree(buf);
 284         return blk;
 285 out_buf:
 286         kfree(buf);
 287         return 0;
 288 }
 289
 290 /* Insert reference to structure into the trie */
 291 static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 292                           uint *treeblk, int depth)
 293 {
 294         char *buf = getdqbuf(info->dqi_usable_bs);
 295         int ret = 0, newson = 0, newact = 0;
 296         __le32 *ref;
 297         uint newblk;
 298
 299         if (!buf)
 300                 return -ENOMEM;
 301         if (!*treeblk) {
 302                 ret = get_free_dqblk(info);
 303                 if (ret < 0)
 304                         goto out_buf;
 305                 *treeblk = ret;
 306                 memset(buf, 0, info->dqi_usable_bs);
 307                 newact = 1;
 308         } else {
 309                 ret = read_blk(info, *treeblk, buf);
 310                 if (ret < 0) {
 311                         quota_error(dquot->dq_sb, "Can't read tree quota "
 312                                     "block %u", *treeblk);
 313                         goto out_buf;
 314                 }
 315         }
 316         ref = (__le32 *)buf;
 317         newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 318         if (!newblk)
 319                 newson = 1;
 320         if (depth == info->dqi_qtree_depth - 1) {
 321 #ifdef __QUOTA_QT_PARANOIA
 322                 if (newblk) {
 323                         quota_error(dquot->dq_sb, "Inserting already present "
 324                                     "quota entry (block %u)",
 325                                     le32_to_cpu(ref[get_index(info,
 326                                                 dquot->dq_id, depth)]));
 327                         ret = -EIO;
 328                         goto out_buf;
 329                 }
 330 #endif
 331                 newblk = find_free_dqentry(info, dquot, &ret);
 332         } else {
 333                 ret = do_insert_tree(info, dquot, &newblk, depth+1);
 334         }
 335         if (newson && ret >= 0) {
 336                 ref[get_index(info, dquot->dq_id, depth)] =
 337                                                         cpu_to_le32(newblk);
 338                 ret = write_blk(info, *treeblk, buf);
 339         } else if (newact && ret < 0) {
 340                 put_free_dqblk(info, buf, *treeblk);
 341         }
 342 out_buf:
 343         kfree(buf);
 344         return ret;
 345 }
 346
 347 /* Wrapper for inserting quota structure into tree */
 348 static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
 349                                  struct dquot *dquot)
 350 {
 351         int tmp = QT_TREEOFF;
 352         return do_insert_tree(info, dquot, &tmp, 0);
 353 }
 354
 355 /*
 356  * We don't have to be afraid of deadlocks as we never have quotas on quota
 357  * files...
 358  */
 359 int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 360 {
 361         int type = dquot->dq_id.type;
 362         struct super_block *sb = dquot->dq_sb;
 363         ssize_t ret;
 364         char *ddquot = getdqbuf(info->dqi_entry_size);
 365
 366         if (!ddquot)
 367                 return -ENOMEM;
 368
 369         /* dq_off is guarded by dqio_mutex */
 370         if (!dquot->dq_off) {
 371                 ret = dq_insert_tree(info, dquot);
 372                 if (ret < 0) {
 373                         quota_error(sb, "Error %zd occurred while creating "
 374                                     "quota", ret);
 375                         kfree(ddquot);
 376                         return ret;
 377                 }
 378         }
 379         spin_lock(&dq_data_lock);
 380         info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
 381         spin_unlock(&dq_data_lock);
 382         ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
 383                                     dquot->dq_off);
 384         if (ret != info->dqi_entry_size) {
 385                 quota_error(sb, "dquota write failed");
 386                 if (ret >= 0)
 387                         ret = -ENOSPC;
 388         } else {
 389                 ret = 0;
 390         }
 391         dqstats_inc(DQST_WRITES);
 392         kfree(ddquot);
 393
 394         return ret;
 395 }
 396 EXPORT_SYMBOL(qtree_write_dquot);
 397
 398 /* Free dquot entry in data block */
 399 static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 400                         uint blk)
 401 {
 402         struct qt_disk_dqdbheader *dh;
 403         char *buf = getdqbuf(info->dqi_usable_bs);
 404         int ret = 0;
 405
 406         if (!buf)
 407                 return -ENOMEM;
 408         if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
 409                 quota_error(dquot->dq_sb, "Quota structure has offset to "
 410                         "other block (%u) than it should (%u)", blk,
 411                         (uint)(dquot->dq_off >> info->dqi_blocksize_bits));
 412                 goto out_buf;
 413         }
 414         ret = read_blk(info, blk, buf);
 415         if (ret < 0) {
 416                 quota_error(dquot->dq_sb, "Can't read quota data block %u",
 417                             blk);
 418                 goto out_buf;
 419         }
 420         dh = (struct qt_disk_dqdbheader *)buf;
 421         le16_add_cpu(&dh->dqdh_entries, -1);
 422         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 423                 ret = remove_free_dqentry(info, buf, blk);
 424                 if (ret >= 0)
 425                         ret = put_free_dqblk(info, buf, blk);
 426                 if (ret < 0) {
 427                         quota_error(dquot->dq_sb, "Can't move quota data block "
 428                                     "(%u) to free list", blk);
 429                         goto out_buf;
 430                 }
 431         } else {
 432                 memset(buf +
 433                        (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
 434                        0, info->dqi_entry_size);
 435                 if (le16_to_cpu(dh->dqdh_entries) ==
 436                     qtree_dqstr_in_blk(info) - 1) {
 437                         /* Insert will write block itself */
 438                         ret = insert_free_dqentry(info, buf, blk);
 439                         if (ret < 0) {
 440                                 quota_error(dquot->dq_sb, "Can't insert quota "
 441                                     "data block (%u) to free entry list", blk);
 442                                 goto out_buf;
 443                         }
 444                 } else {
 445                         ret = write_blk(info, blk, buf);
 446                         if (ret < 0) {
 447                                 quota_error(dquot->dq_sb, "Can't write quota "
 448                                             "data block %u", blk);
 449                                 goto out_buf;
 450                         }
 451                 }
 452         }
 453         dquot->dq_off = 0;      /* Quota is now unattached */
 454 out_buf:
 455         kfree(buf);
 456         return ret;
 457 }
 458
 459 /* Remove reference to dquot from tree */
 460 static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 461                        uint *blk, int depth)
 462 {
 463         char *buf = getdqbuf(info->dqi_usable_bs);
 464         int ret = 0;
 465         uint newblk;
 466         __le32 *ref = (__le32 *)buf;
 467
 468         if (!buf)
 469                 return -ENOMEM;
 470         ret = read_blk(info, *blk, buf);
 471         if (ret < 0) {
 472                 quota_error(dquot->dq_sb, "Can't read quota data block %u",
 473                             *blk);
 474                 goto out_buf;
 475         }
 476         newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 477         if (depth == info->dqi_qtree_depth - 1) {
 478                 ret = free_dqentry(info, dquot, newblk);
 479                 newblk = 0;
 480         } else {
 481                 ret = remove_tree(info, dquot, &newblk, depth+1);
 482         }
 483         if (ret >= 0 && !newblk) {
 484                 int i;
 485                 ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
 486                 /* Block got empty? */
 487                 for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
 488                         ;
 489                 /* Don't put the root block into the free block list */
 490                 if (i == (info->dqi_usable_bs >> 2)
 491                     && *blk != QT_TREEOFF) {
 492                         put_free_dqblk(info, buf, *blk);
 493                         *blk = 0;
 494                 } else {
 495                         ret = write_blk(info, *blk, buf);
 496                         if (ret < 0)
 497                                 quota_error(dquot->dq_sb,
 498                                             "Can't write quota tree block %u",
 499                                             *blk);
 500                 }
 501         }
 502 out_buf:
 503         kfree(buf);
 504         return ret;
 505 }
 506
 507 /* Delete dquot from tree */
 508 int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 509 {
 510         uint tmp = QT_TREEOFF;
 511
 512         if (!dquot->dq_off)     /* Even not allocated? */
 513                 return 0;
 514         return remove_tree(info, dquot, &tmp, 0);
 515 }
 516 EXPORT_SYMBOL(qtree_delete_dquot);
 517
 518 /* Find entry in block */
 519 static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
 520                                  struct dquot *dquot, uint blk)
 521 {
 522         char *buf = getdqbuf(info->dqi_usable_bs);
 523         loff_t ret = 0;
 524         int i;
 525         char *ddquot;
 526
 527         if (!buf)
 528                 return -ENOMEM;
 529         ret = read_blk(info, blk, buf);
 530         if (ret < 0) {
 531                 quota_error(dquot->dq_sb, "Can't read quota tree "
 532                             "block %u", blk);
 533                 goto out_buf;
 534         }
 535         ddquot = buf + sizeof(struct qt_disk_dqdbheader);
 536         for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
 537                 if (info->dqi_ops->is_id(ddquot, dquot))
 538                         break;
 539                 ddquot += info->dqi_entry_size;
 540         }
 541         if (i == qtree_dqstr_in_blk(info)) {
 542                 quota_error(dquot->dq_sb,
 543                             "Quota for id %u referenced but not present",
 544                             from_kqid(&init_user_ns, dquot->dq_id));
 545                 ret = -EIO;
 546                 goto out_buf;
 547         } else {
 548                 ret = (blk << info->dqi_blocksize_bits) + sizeof(struct
 549                   qt_disk_dqdbheader) + i * info->dqi_entry_size;
 550         }
 551 out_buf:
 552         kfree(buf);
 553         return ret;
 554 }
 555
 556 /* Find entry for given id in the tree */
 557 static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
 558                                 struct dquot *dquot, uint blk, int depth)
 559 {
 560         char *buf = getdqbuf(info->dqi_usable_bs);
 561         loff_t ret = 0;
 562         __le32 *ref = (__le32 *)buf;
 563
 564         if (!buf)
 565                 return -ENOMEM;
 566         ret = read_blk(info, blk, buf);
 567         if (ret < 0) {
 568                 quota_error(dquot->dq_sb, "Can't read quota tree block %u",
 569                             blk);
 570                 goto out_buf;
 571         }
 572         ret = 0;
 573         blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 574         if (!blk)       /* No reference? */
 575                 goto out_buf;
 576         if (depth < info->dqi_qtree_depth - 1)
 577                 ret = find_tree_dqentry(info, dquot, blk, depth+1);
 578         else
 579                 ret = find_block_dqentry(info, dquot, blk);
 580 out_buf:
 581         kfree(buf);
 582         return ret;
 583 }
 584
 585 /* Find entry for given id in the tree - wrapper function */
 586 static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
 587                                   struct dquot *dquot)
 588 {
 589         return find_tree_dqentry(info, dquot, QT_TREEOFF, 0);
 590 }
 591
 592 int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 593 {
 594         int type = dquot->dq_id.type;
 595         struct super_block *sb = dquot->dq_sb;
 596         loff_t offset;
 597         char *ddquot;
 598         int ret = 0;
 599
 600 #ifdef __QUOTA_QT_PARANOIA
 601         /* Invalidated quota? */
 602         if (!sb_dqopt(dquot->dq_sb)->files[type]) {
 603                 quota_error(sb, "Quota invalidated while reading!");
 604                 return -EIO;
 605         }
 606 #endif
 607         /* Do we know offset of the dquot entry in the quota file? */
 608         if (!dquot->dq_off) {
 609                 offset = find_dqentry(info, dquot);
 610                 if (offset <= 0) {      /* Entry not present? */
 611                         if (offset < 0)
 612                                 quota_error(sb,"Can't read quota structure "
 613                                             "for id %u",
 614                                             from_kqid(&init_user_ns,
 615                                                       dquot->dq_id));
 616                         dquot->dq_off = 0;
 617                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
 618                         memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 619                         ret = offset;
 620                         goto out;
 621                 }
 622                 dquot->dq_off = offset;
 623         }
 624         ddquot = getdqbuf(info->dqi_entry_size);
 625         if (!ddquot)
 626                 return -ENOMEM;
 627         ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
 628                                    dquot->dq_off);
 629         if (ret != info->dqi_entry_size) {
 630                 if (ret >= 0)
 631                         ret = -EIO;
 632                 quota_error(sb, "Error while reading quota structure for id %u",
 633                             from_kqid(&init_user_ns, dquot->dq_id));
 634                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 635                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 636                 kfree(ddquot);
 637                 goto out;
 638         }
 639         spin_lock(&dq_data_lock);
 640         info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
 641         if (!dquot->dq_dqb.dqb_bhardlimit &&
 642             !dquot->dq_dqb.dqb_bsoftlimit &&
 643             !dquot->dq_dqb.dqb_ihardlimit &&
 644             !dquot->dq_dqb.dqb_isoftlimit)
 645                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 646         spin_unlock(&dq_data_lock);
 647         kfree(ddquot);
 648 out:
 649         dqstats_inc(DQST_READS);
 650         return ret;
 651 }
 652 EXPORT_SYMBOL(qtree_read_dquot);
 653
 654 /* Check whether dquot should not be deleted. We know we are
 655  * the only one operating on dquot (thanks to dq_lock) */
 656 int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 657 {
 658         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
 659             !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 660                 return qtree_delete_dquot(info, dquot);
 661         return 0;
 662 }
 663 EXPORT_SYMBOL(qtree_release_dquot);