git.oblomov.eu Git - linux-2.6/blob - 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, qid_t id, int depth)
  26 {
  27         unsigned int epb = info->dqi_usable_bs >> 2;
  28
  29         depth = info->dqi_qtree_depth - depth - 1;
  30         while (depth--)
  31                 id /= epb;
  32         return id % epb;
  33 }
  34
  35 /* Number of entries in one blocks */
  36 static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
  37 {
  38         return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
  39                / info->dqi_entry_size;
  40 }
  41
  42 static char *getdqbuf(size_t size)
  43 {
  44         char *buf = kmalloc(size, GFP_NOFS);
  45         if (!buf)
  46                 printk(KERN_WARNING
  47                        "VFS: Not enough memory for quota buffers.\n");
  48         return buf;
  49 }
  50
  51 static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
  52 {
  53         struct super_block *sb = info->dqi_sb;
  54
  55         memset(buf, 0, info->dqi_usable_bs);
  56         return sb->s_op->quota_read(sb, info->dqi_type, buf,
  57                info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
  58 }
  59
  60 static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
  61 {
  62         struct super_block *sb = info->dqi_sb;
  63
  64         return sb->s_op->quota_write(sb, info->dqi_type, buf,
  65                info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
  66 }
  67
  68 /* Remove empty block from list and return it */
  69 static int get_free_dqblk(struct qtree_mem_dqinfo *info)
  70 {
  71         char *buf = getdqbuf(info->dqi_usable_bs);
  72         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
  73         int ret, blk;
  74
  75         if (!buf)
  76                 return -ENOMEM;
  77         if (info->dqi_free_blk) {
  78                 blk = info->dqi_free_blk;
  79                 ret = read_blk(info, blk, buf);
  80                 if (ret < 0)
  81                         goto out_buf;
  82                 info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
  83         }
  84         else {
  85                 memset(buf, 0, info->dqi_usable_bs);
  86                 /* Assure block allocation... */
  87                 ret = write_blk(info, info->dqi_blocks, buf);
  88                 if (ret < 0)
  89                         goto out_buf;
  90                 blk = info->dqi_blocks++;
  91         }
  92         mark_info_dirty(info->dqi_sb, info->dqi_type);
  93         ret = blk;
  94 out_buf:
  95         kfree(buf);
  96         return ret;
  97 }
  98
  99 /* Insert empty block to the list */
 100 static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
 101 {
 102         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 103         int err;
 104
 105         dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
 106         dh->dqdh_prev_free = cpu_to_le32(0);
 107         dh->dqdh_entries = cpu_to_le16(0);
 108         err = write_blk(info, blk, buf);
 109         if (err < 0)
 110                 return err;
 111         info->dqi_free_blk = blk;
 112         mark_info_dirty(info->dqi_sb, info->dqi_type);
 113         return 0;
 114 }
 115
 116 /* Remove given block from the list of blocks with free entries */
 117 static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
 118                                uint blk)
 119 {
 120         char *tmpbuf = getdqbuf(info->dqi_usable_bs);
 121         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 122         uint nextblk = le32_to_cpu(dh->dqdh_next_free);
 123         uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
 124         int err;
 125
 126         if (!tmpbuf)
 127                 return -ENOMEM;
 128         if (nextblk) {
 129                 err = read_blk(info, nextblk, tmpbuf);
 130                 if (err < 0)
 131                         goto out_buf;
 132                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
 133                                                         dh->dqdh_prev_free;
 134                 err = write_blk(info, nextblk, tmpbuf);
 135                 if (err < 0)
 136                         goto out_buf;
 137         }
 138         if (prevblk) {
 139                 err = read_blk(info, prevblk, tmpbuf);
 140                 if (err < 0)
 141                         goto out_buf;
 142                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
 143                                                         dh->dqdh_next_free;
 144                 err = write_blk(info, prevblk, tmpbuf);
 145                 if (err < 0)
 146                         goto out_buf;
 147         } else {
 148                 info->dqi_free_entry = nextblk;
 149                 mark_info_dirty(info->dqi_sb, info->dqi_type);
 150         }
 151         kfree(tmpbuf);
 152         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 153         /* No matter whether write succeeds block is out of list */
 154         if (write_blk(info, blk, buf) < 0)
 155                 printk(KERN_ERR
 156                        "VFS: Can't write block (%u) with free entries.\n",
 157                        blk);
 158         return 0;
 159 out_buf:
 160         kfree(tmpbuf);
 161         return err;
 162 }
 163
 164 /* Insert given block to the beginning of list with free entries */
 165 static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
 166                                uint blk)
 167 {
 168         char *tmpbuf = getdqbuf(info->dqi_usable_bs);
 169         struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
 170         int err;
 171
 172         if (!tmpbuf)
 173                 return -ENOMEM;
 174         dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
 175         dh->dqdh_prev_free = cpu_to_le32(0);
 176         err = write_blk(info, blk, buf);
 177         if (err < 0)
 178                 goto out_buf;
 179         if (info->dqi_free_entry) {
 180                 err = read_blk(info, info->dqi_free_entry, tmpbuf);
 181                 if (err < 0)
 182                         goto out_buf;
 183                 ((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
 184                                                         cpu_to_le32(blk);
 185                 err = write_blk(info, info->dqi_free_entry, tmpbuf);
 186                 if (err < 0)
 187                         goto out_buf;
 188         }
 189         kfree(tmpbuf);
 190         info->dqi_free_entry = blk;
 191         mark_info_dirty(info->dqi_sb, info->dqi_type);
 192         return 0;
 193 out_buf:
 194         kfree(tmpbuf);
 195         return err;
 196 }
 197
 198 /* Is the entry in the block free? */
 199 int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
 200 {
 201         int i;
 202
 203         for (i = 0; i < info->dqi_entry_size; i++)
 204                 if (disk[i])
 205                         return 0;
 206         return 1;
 207 }
 208 EXPORT_SYMBOL(qtree_entry_unused);
 209
 210 /* Find space for dquot */
 211 static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
 212                               struct dquot *dquot, int *err)
 213 {
 214         uint blk, i;
 215         struct qt_disk_dqdbheader *dh;
 216         char *buf = getdqbuf(info->dqi_usable_bs);
 217         char *ddquot;
 218
 219         *err = 0;
 220         if (!buf) {
 221                 *err = -ENOMEM;
 222                 return 0;
 223         }
 224         dh = (struct qt_disk_dqdbheader *)buf;
 225         if (info->dqi_free_entry) {
 226                 blk = info->dqi_free_entry;
 227                 *err = read_blk(info, blk, buf);
 228                 if (*err < 0)
 229                         goto out_buf;
 230         } else {
 231                 blk = get_free_dqblk(info);
 232                 if ((int)blk < 0) {
 233                         *err = blk;
 234                         kfree(buf);
 235                         return 0;
 236                 }
 237                 memset(buf, 0, info->dqi_usable_bs);
 238                 /* This is enough as the block is already zeroed and the entry
 239                  * list is empty... */
 240                 info->dqi_free_entry = blk;
 241                 mark_info_dirty(dquot->dq_sb, dquot->dq_type);
 242         }
 243         /* Block will be full? */
 244         if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
 245                 *err = remove_free_dqentry(info, buf, blk);
 246                 if (*err < 0) {
 247                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't "
 248                                "remove block (%u) from entry free list.\n",
 249                                blk);
 250                         goto out_buf;
 251                 }
 252         }
 253         le16_add_cpu(&dh->dqdh_entries, 1);
 254         /* Find free structure in block */
 255         ddquot = buf + sizeof(struct qt_disk_dqdbheader);
 256         for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
 257                 if (qtree_entry_unused(info, ddquot))
 258                         break;
 259                 ddquot += info->dqi_entry_size;
 260         }
 261 #ifdef __QUOTA_QT_PARANOIA
 262         if (i == qtree_dqstr_in_blk(info)) {
 263                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full "
 264                                 "but it shouldn't.\n");
 265                 *err = -EIO;
 266                 goto out_buf;
 267         }
 268 #endif
 269         *err = write_blk(info, blk, buf);
 270         if (*err < 0) {
 271                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota "
 272                                 "data block %u.\n", blk);
 273                 goto out_buf;
 274         }
 275         dquot->dq_off = (blk << info->dqi_blocksize_bits) +
 276                         sizeof(struct qt_disk_dqdbheader) +
 277                         i * info->dqi_entry_size;
 278         kfree(buf);
 279         return blk;
 280 out_buf:
 281         kfree(buf);
 282         return 0;
 283 }
 284
 285 /* Insert reference to structure into the trie */
 286 static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 287                           uint *treeblk, int depth)
 288 {
 289         char *buf = getdqbuf(info->dqi_usable_bs);
 290         int ret = 0, newson = 0, newact = 0;
 291         __le32 *ref;
 292         uint newblk;
 293
 294         if (!buf)
 295                 return -ENOMEM;
 296         if (!*treeblk) {
 297                 ret = get_free_dqblk(info);
 298                 if (ret < 0)
 299                         goto out_buf;
 300                 *treeblk = ret;
 301                 memset(buf, 0, info->dqi_usable_bs);
 302                 newact = 1;
 303         } else {
 304                 ret = read_blk(info, *treeblk, buf);
 305                 if (ret < 0) {
 306                         printk(KERN_ERR "VFS: Can't read tree quota block "
 307                                         "%u.\n", *treeblk);
 308                         goto out_buf;
 309                 }
 310         }
 311         ref = (__le32 *)buf;
 312         newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 313         if (!newblk)
 314                 newson = 1;
 315         if (depth == info->dqi_qtree_depth - 1) {
 316 #ifdef __QUOTA_QT_PARANOIA
 317                 if (newblk) {
 318                         printk(KERN_ERR "VFS: Inserting already present quota "
 319                                         "entry (block %u).\n",
 320                                le32_to_cpu(ref[get_index(info,
 321                                                 dquot->dq_id, depth)]));
 322                         ret = -EIO;
 323                         goto out_buf;
 324                 }
 325 #endif
 326                 newblk = find_free_dqentry(info, dquot, &ret);
 327         } else {
 328                 ret = do_insert_tree(info, dquot, &newblk, depth+1);
 329         }
 330         if (newson && ret >= 0) {
 331                 ref[get_index(info, dquot->dq_id, depth)] =
 332                                                         cpu_to_le32(newblk);
 333                 ret = write_blk(info, *treeblk, buf);
 334         } else if (newact && ret < 0) {
 335                 put_free_dqblk(info, buf, *treeblk);
 336         }
 337 out_buf:
 338         kfree(buf);
 339         return ret;
 340 }
 341
 342 /* Wrapper for inserting quota structure into tree */
 343 static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
 344                                  struct dquot *dquot)
 345 {
 346         int tmp = QT_TREEOFF;
 347         return do_insert_tree(info, dquot, &tmp, 0);
 348 }
 349
 350 /*
 351  * We don't have to be afraid of deadlocks as we never have quotas on quota
 352  * files...
 353  */
 354 int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 355 {
 356         int type = dquot->dq_type;
 357         struct super_block *sb = dquot->dq_sb;
 358         ssize_t ret;
 359         char *ddquot = getdqbuf(info->dqi_entry_size);
 360
 361         if (!ddquot)
 362                 return -ENOMEM;
 363
 364         /* dq_off is guarded by dqio_mutex */
 365         if (!dquot->dq_off) {
 366                 ret = dq_insert_tree(info, dquot);
 367                 if (ret < 0) {
 368                         printk(KERN_ERR "VFS: Error %zd occurred while "
 369                                         "creating quota.\n", ret);
 370                         kfree(ddquot);
 371                         return ret;
 372                 }
 373         }
 374         spin_lock(&dq_data_lock);
 375         info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
 376         spin_unlock(&dq_data_lock);
 377         ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
 378                                     dquot->dq_off);
 379         if (ret != info->dqi_entry_size) {
 380                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n",
 381                        sb->s_id);
 382                 if (ret >= 0)
 383                         ret = -ENOSPC;
 384         } else {
 385                 ret = 0;
 386         }
 387         dqstats.writes++;
 388         kfree(ddquot);
 389
 390         return ret;
 391 }
 392 EXPORT_SYMBOL(qtree_write_dquot);
 393
 394 /* Free dquot entry in data block */
 395 static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 396                         uint blk)
 397 {
 398         struct qt_disk_dqdbheader *dh;
 399         char *buf = getdqbuf(info->dqi_usable_bs);
 400         int ret = 0;
 401
 402         if (!buf)
 403                 return -ENOMEM;
 404         if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
 405                 printk(KERN_ERR "VFS: Quota structure has offset to other "
 406                   "block (%u) than it should (%u).\n", blk,
 407                   (uint)(dquot->dq_off >> info->dqi_blocksize_bits));
 408                 goto out_buf;
 409         }
 410         ret = read_blk(info, blk, buf);
 411         if (ret < 0) {
 412                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 413                 goto out_buf;
 414         }
 415         dh = (struct qt_disk_dqdbheader *)buf;
 416         le16_add_cpu(&dh->dqdh_entries, -1);
 417         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 418                 ret = remove_free_dqentry(info, buf, blk);
 419                 if (ret >= 0)
 420                         ret = put_free_dqblk(info, buf, blk);
 421                 if (ret < 0) {
 422                         printk(KERN_ERR "VFS: Can't move quota data block (%u) "
 423                           "to free list.\n", blk);
 424                         goto out_buf;
 425                 }
 426         } else {
 427                 memset(buf +
 428                        (dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
 429                        0, info->dqi_entry_size);
 430                 if (le16_to_cpu(dh->dqdh_entries) ==
 431                     qtree_dqstr_in_blk(info) - 1) {
 432                         /* Insert will write block itself */
 433                         ret = insert_free_dqentry(info, buf, blk);
 434                         if (ret < 0) {
 435                                 printk(KERN_ERR "VFS: Can't insert quota data "
 436                                        "block (%u) to free entry list.\n", blk);
 437                                 goto out_buf;
 438                         }
 439                 } else {
 440                         ret = write_blk(info, blk, buf);
 441                         if (ret < 0) {
 442                                 printk(KERN_ERR "VFS: Can't write quota data "
 443                                   "block %u\n", blk);
 444                                 goto out_buf;
 445                         }
 446                 }
 447         }
 448         dquot->dq_off = 0;      /* Quota is now unattached */
 449 out_buf:
 450         kfree(buf);
 451         return ret;
 452 }
 453
 454 /* Remove reference to dquot from tree */
 455 static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 456                        uint *blk, int depth)
 457 {
 458         char *buf = getdqbuf(info->dqi_usable_bs);
 459         int ret = 0;
 460         uint newblk;
 461         __le32 *ref = (__le32 *)buf;
 462
 463         if (!buf)
 464                 return -ENOMEM;
 465         ret = read_blk(info, *blk, buf);
 466         if (ret < 0) {
 467                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 468                 goto out_buf;
 469         }
 470         newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 471         if (depth == info->dqi_qtree_depth - 1) {
 472                 ret = free_dqentry(info, dquot, newblk);
 473                 newblk = 0;
 474         } else {
 475                 ret = remove_tree(info, dquot, &newblk, depth+1);
 476         }
 477         if (ret >= 0 && !newblk) {
 478                 int i;
 479                 ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
 480                 /* Block got empty? */
 481                 for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
 482                         ;
 483                 /* Don't put the root block into the free block list */
 484                 if (i == (info->dqi_usable_bs >> 2)
 485                     && *blk != QT_TREEOFF) {
 486                         put_free_dqblk(info, buf, *blk);
 487                         *blk = 0;
 488                 } else {
 489                         ret = write_blk(info, *blk, buf);
 490                         if (ret < 0)
 491                                 printk(KERN_ERR "VFS: Can't write quota tree "
 492                                   "block %u.\n", *blk);
 493                 }
 494         }
 495 out_buf:
 496         kfree(buf);
 497         return ret;
 498 }
 499
 500 /* Delete dquot from tree */
 501 int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 502 {
 503         uint tmp = QT_TREEOFF;
 504
 505         if (!dquot->dq_off)     /* Even not allocated? */
 506                 return 0;
 507         return remove_tree(info, dquot, &tmp, 0);
 508 }
 509 EXPORT_SYMBOL(qtree_delete_dquot);
 510
 511 /* Find entry in block */
 512 static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
 513                                  struct dquot *dquot, uint blk)
 514 {
 515         char *buf = getdqbuf(info->dqi_usable_bs);
 516         loff_t ret = 0;
 517         int i;
 518         char *ddquot;
 519
 520         if (!buf)
 521                 return -ENOMEM;
 522         ret = read_blk(info, blk, buf);
 523         if (ret < 0) {
 524                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 525                 goto out_buf;
 526         }
 527         ddquot = buf + sizeof(struct qt_disk_dqdbheader);
 528         for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
 529                 if (info->dqi_ops->is_id(ddquot, dquot))
 530                         break;
 531                 ddquot += info->dqi_entry_size;
 532         }
 533         if (i == qtree_dqstr_in_blk(info)) {
 534                 printk(KERN_ERR "VFS: Quota for id %u referenced "
 535                   "but not present.\n", dquot->dq_id);
 536                 ret = -EIO;
 537                 goto out_buf;
 538         } else {
 539                 ret = (blk << info->dqi_blocksize_bits) + sizeof(struct
 540                   qt_disk_dqdbheader) + i * info->dqi_entry_size;
 541         }
 542 out_buf:
 543         kfree(buf);
 544         return ret;
 545 }
 546
 547 /* Find entry for given id in the tree */
 548 static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
 549                                 struct dquot *dquot, uint blk, int depth)
 550 {
 551         char *buf = getdqbuf(info->dqi_usable_bs);
 552         loff_t ret = 0;
 553         __le32 *ref = (__le32 *)buf;
 554
 555         if (!buf)
 556                 return -ENOMEM;
 557         ret = read_blk(info, blk, buf);
 558         if (ret < 0) {
 559                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 560                 goto out_buf;
 561         }
 562         ret = 0;
 563         blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 564         if (!blk)       /* No reference? */
 565                 goto out_buf;
 566         if (depth < info->dqi_qtree_depth - 1)
 567                 ret = find_tree_dqentry(info, dquot, blk, depth+1);
 568         else
 569                 ret = find_block_dqentry(info, dquot, blk);
 570 out_buf:
 571         kfree(buf);
 572         return ret;
 573 }
 574
 575 /* Find entry for given id in the tree - wrapper function */
 576 static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
 577                                   struct dquot *dquot)
 578 {
 579         return find_tree_dqentry(info, dquot, QT_TREEOFF, 0);
 580 }
 581
 582 int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 583 {
 584         int type = dquot->dq_type;
 585         struct super_block *sb = dquot->dq_sb;
 586         loff_t offset;
 587         char *ddquot;
 588         int ret = 0;
 589
 590 #ifdef __QUOTA_QT_PARANOIA
 591         /* Invalidated quota? */
 592         if (!sb_dqopt(dquot->dq_sb)->files[type]) {
 593                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 594                 return -EIO;
 595         }
 596 #endif
 597         /* Do we know offset of the dquot entry in the quota file? */
 598         if (!dquot->dq_off) {
 599                 offset = find_dqentry(info, dquot);
 600                 if (offset <= 0) {      /* Entry not present? */
 601                         if (offset < 0)
 602                                 printk(KERN_ERR "VFS: Can't read quota "
 603                                   "structure for id %u.\n", dquot->dq_id);
 604                         dquot->dq_off = 0;
 605                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
 606                         memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 607                         ret = offset;
 608                         goto out;
 609                 }
 610                 dquot->dq_off = offset;
 611         }
 612         ddquot = getdqbuf(info->dqi_entry_size);
 613         if (!ddquot)
 614                 return -ENOMEM;
 615         ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
 616                                    dquot->dq_off);
 617         if (ret != info->dqi_entry_size) {
 618                 if (ret >= 0)
 619                         ret = -EIO;
 620                 printk(KERN_ERR "VFS: Error while reading quota "
 621                                 "structure for id %u.\n", dquot->dq_id);
 622                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 623                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 624                 kfree(ddquot);
 625                 goto out;
 626         }
 627         spin_lock(&dq_data_lock);
 628         info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
 629         if (!dquot->dq_dqb.dqb_bhardlimit &&
 630             !dquot->dq_dqb.dqb_bsoftlimit &&
 631             !dquot->dq_dqb.dqb_ihardlimit &&
 632             !dquot->dq_dqb.dqb_isoftlimit)
 633                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 634         spin_unlock(&dq_data_lock);
 635         kfree(ddquot);
 636 out:
 637         dqstats.reads++;
 638         return ret;
 639 }
 640 EXPORT_SYMBOL(qtree_read_dquot);
 641
 642 /* Check whether dquot should not be deleted. We know we are
 643  * the only one operating on dquot (thanks to dq_lock) */
 644 int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
 645 {
 646         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
 647             !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 648                 return qtree_delete_dquot(info, dquot);
 649         return 0;
 650 }
 651 EXPORT_SYMBOL(qtree_release_dquot);