fs/quota_v2.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/quotaio_v2.h>
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14
  15 #include <asm/byteorder.h>
  16
  17 MODULE_AUTHOR("Jan Kara");
  18 MODULE_DESCRIPTION("Quota format v2 support");
  19 MODULE_LICENSE("GPL");
  20
  21 #define __QUOTA_V2_PARANOIA
  22
  23 typedef char *dqbuf_t;
  24
  25 #define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
  26 #define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))
  27
  28 /* Check whether given file is really vfsv0 quotafile */
  29 static int v2_check_quota_file(struct super_block *sb, int type)
  30 {
  31         struct v2_disk_dqheader dqhead;
  32         ssize_t size;
  33         static const uint quota_magics[] = V2_INITQMAGICS;
  34         static const uint quota_versions[] = V2_INITQVERSIONS;
  35
  36         size = sb->s_op->quota_read(sb, type, (char *)&dqhead, sizeof(struct v2_disk_dqheader), 0);
  37         if (size != sizeof(struct v2_disk_dqheader)) {
  38                 printk("quota_v2: failed read expected=%zd got=%zd\n",
  39                         sizeof(struct v2_disk_dqheader), size);
  40                 return 0;
  41         }
  42         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
  43             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
  44                 return 0;
  45         return 1;
  46 }
  47
  48 /* Read information header from quota file */
  49 static int v2_read_file_info(struct super_block *sb, int type)
  50 {
  51         struct v2_disk_dqinfo dinfo;
  52         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  53         ssize_t size;
  54
  55         size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
  56                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
  57         if (size != sizeof(struct v2_disk_dqinfo)) {
  58                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
  59                         sb->s_id);
  60                 return -1;
  61         }
  62         /* limits are stored as unsigned 32-bit data */
  63         info->dqi_maxblimit = 0xffffffff;
  64         info->dqi_maxilimit = 0xffffffff;
  65         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
  66         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
  67         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
  68         info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
  69         info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
  70         info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
  71         return 0;
  72 }
  73
  74 /* Write information header to quota file */
  75 static int v2_write_file_info(struct super_block *sb, int type)
  76 {
  77         struct v2_disk_dqinfo dinfo;
  78         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  79         ssize_t size;
  80
  81         spin_lock(&dq_data_lock);
  82         info->dqi_flags &= ~DQF_INFO_DIRTY;
  83         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
  84         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
  85         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
  86         spin_unlock(&dq_data_lock);
  87         dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
  88         dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
  89         dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
  90         size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
  91                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
  92         if (size != sizeof(struct v2_disk_dqinfo)) {
  93                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
  94                         sb->s_id);
  95                 return -1;
  96         }
  97         return 0;
  98 }
  99
 100 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
 101 {
 102         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
 103         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
 104         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
 105         m->dqb_itime = le64_to_cpu(d->dqb_itime);
 106         m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
 107         m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
 108         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
 109         m->dqb_btime = le64_to_cpu(d->dqb_btime);
 110 }
 111
 112 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
 113 {
 114         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
 115         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
 116         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
 117         d->dqb_itime = cpu_to_le64(m->dqb_itime);
 118         d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
 119         d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
 120         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
 121         d->dqb_btime = cpu_to_le64(m->dqb_btime);
 122         d->dqb_id = cpu_to_le32(id);
 123 }
 124
 125 static dqbuf_t getdqbuf(void)
 126 {
 127         dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_NOFS);
 128         if (!buf)
 129                 printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
 130         return buf;
 131 }
 132
 133 static inline void freedqbuf(dqbuf_t buf)
 134 {
 135         kfree(buf);
 136 }
 137
 138 static inline ssize_t read_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
 139 {
 140         memset(buf, 0, V2_DQBLKSIZE);
 141         return sb->s_op->quota_read(sb, type, (char *)buf,
 142                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
 143 }
 144
 145 static inline ssize_t write_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
 146 {
 147         return sb->s_op->quota_write(sb, type, (char *)buf,
 148                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
 149 }
 150
 151 /* Remove empty block from list and return it */
 152 static int get_free_dqblk(struct super_block *sb, int type)
 153 {
 154         dqbuf_t buf = getdqbuf();
 155         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 156         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 157         int ret, blk;
 158
 159         if (!buf)
 160                 return -ENOMEM;
 161         if (info->u.v2_i.dqi_free_blk) {
 162                 blk = info->u.v2_i.dqi_free_blk;
 163                 if ((ret = read_blk(sb, type, blk, buf)) < 0)
 164                         goto out_buf;
 165                 info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
 166         }
 167         else {
 168                 memset(buf, 0, V2_DQBLKSIZE);
 169                 /* Assure block allocation... */
 170                 if ((ret = write_blk(sb, type, info->u.v2_i.dqi_blocks, buf)) < 0)
 171                         goto out_buf;
 172                 blk = info->u.v2_i.dqi_blocks++;
 173         }
 174         mark_info_dirty(sb, type);
 175         ret = blk;
 176 out_buf:
 177         freedqbuf(buf);
 178         return ret;
 179 }
 180
 181 /* Insert empty block to the list */
 182 static int put_free_dqblk(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 183 {
 184         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 185         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 186         int err;
 187
 188         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 189         dh->dqdh_prev_free = cpu_to_le32(0);
 190         dh->dqdh_entries = cpu_to_le16(0);
 191         info->u.v2_i.dqi_free_blk = blk;
 192         mark_info_dirty(sb, type);
 193         /* Some strange block. We had better leave it... */
 194         if ((err = write_blk(sb, type, blk, buf)) < 0)
 195                 return err;
 196         return 0;
 197 }
 198
 199 /* Remove given block from the list of blocks with free entries */
 200 static int remove_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 201 {
 202         dqbuf_t tmpbuf = getdqbuf();
 203         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 204         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 205         uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
 206         int err;
 207
 208         if (!tmpbuf)
 209                 return -ENOMEM;
 210         if (nextblk) {
 211                 if ((err = read_blk(sb, type, nextblk, tmpbuf)) < 0)
 212                         goto out_buf;
 213                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
 214                 if ((err = write_blk(sb, type, nextblk, tmpbuf)) < 0)
 215                         goto out_buf;
 216         }
 217         if (prevblk) {
 218                 if ((err = read_blk(sb, type, prevblk, tmpbuf)) < 0)
 219                         goto out_buf;
 220                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
 221                 if ((err = write_blk(sb, type, prevblk, tmpbuf)) < 0)
 222                         goto out_buf;
 223         }
 224         else {
 225                 info->u.v2_i.dqi_free_entry = nextblk;
 226                 mark_info_dirty(sb, type);
 227         }
 228         freedqbuf(tmpbuf);
 229         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 230         /* No matter whether write succeeds block is out of list */
 231         if (write_blk(sb, type, blk, buf) < 0)
 232                 printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
 233         return 0;
 234 out_buf:
 235         freedqbuf(tmpbuf);
 236         return err;
 237 }
 238
 239 /* Insert given block to the beginning of list with free entries */
 240 static int insert_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 241 {
 242         dqbuf_t tmpbuf = getdqbuf();
 243         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 244         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 245         int err;
 246
 247         if (!tmpbuf)
 248                 return -ENOMEM;
 249         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 250         dh->dqdh_prev_free = cpu_to_le32(0);
 251         if ((err = write_blk(sb, type, blk, buf)) < 0)
 252                 goto out_buf;
 253         if (info->u.v2_i.dqi_free_entry) {
 254                 if ((err = read_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 255                         goto out_buf;
 256                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
 257                 if ((err = write_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 258                         goto out_buf;
 259         }
 260         freedqbuf(tmpbuf);
 261         info->u.v2_i.dqi_free_entry = blk;
 262         mark_info_dirty(sb, type);
 263         return 0;
 264 out_buf:
 265         freedqbuf(tmpbuf);
 266         return err;
 267 }
 268
 269 /* Find space for dquot */
 270 static uint find_free_dqentry(struct dquot *dquot, int *err)
 271 {
 272         struct super_block *sb = dquot->dq_sb;
 273         struct mem_dqinfo *info = sb_dqopt(sb)->info+dquot->dq_type;
 274         uint blk, i;
 275         struct v2_disk_dqdbheader *dh;
 276         struct v2_disk_dqblk *ddquot;
 277         struct v2_disk_dqblk fakedquot;
 278         dqbuf_t buf;
 279
 280         *err = 0;
 281         if (!(buf = getdqbuf())) {
 282                 *err = -ENOMEM;
 283                 return 0;
 284         }
 285         dh = (struct v2_disk_dqdbheader *)buf;
 286         ddquot = GETENTRIES(buf);
 287         if (info->u.v2_i.dqi_free_entry) {
 288                 blk = info->u.v2_i.dqi_free_entry;
 289                 if ((*err = read_blk(sb, dquot->dq_type, blk, buf)) < 0)
 290                         goto out_buf;
 291         }
 292         else {
 293                 blk = get_free_dqblk(sb, dquot->dq_type);
 294                 if ((int)blk < 0) {
 295                         *err = blk;
 296                         freedqbuf(buf);
 297                         return 0;
 298                 }
 299                 memset(buf, 0, V2_DQBLKSIZE);
 300                 /* This is enough as block is already zeroed and entry list is empty... */
 301                 info->u.v2_i.dqi_free_entry = blk;
 302                 mark_info_dirty(sb, dquot->dq_type);
 303         }
 304         if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
 305                 if ((*err = remove_free_dqentry(sb, dquot->dq_type, buf, blk)) < 0) {
 306                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
 307                         goto out_buf;
 308                 }
 309         le16_add_cpu(&dh->dqdh_entries, 1);
 310         memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 311         /* Find free structure in block */
 312         for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
 313 #ifdef __QUOTA_V2_PARANOIA
 314         if (i == V2_DQSTRINBLK) {
 315                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
 316                 *err = -EIO;
 317                 goto out_buf;
 318         }
 319 #endif
 320         if ((*err = write_blk(sb, dquot->dq_type, blk, buf)) < 0) {
 321                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
 322                 goto out_buf;
 323         }
 324         dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
 325         freedqbuf(buf);
 326         return blk;
 327 out_buf:
 328         freedqbuf(buf);
 329         return 0;
 330 }
 331
 332 /* Insert reference to structure into the trie */
 333 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
 334 {
 335         struct super_block *sb = dquot->dq_sb;
 336         dqbuf_t buf;
 337         int ret = 0, newson = 0, newact = 0;
 338         __le32 *ref;
 339         uint newblk;
 340
 341         if (!(buf = getdqbuf()))
 342                 return -ENOMEM;
 343         if (!*treeblk) {
 344                 ret = get_free_dqblk(sb, dquot->dq_type);
 345                 if (ret < 0)
 346                         goto out_buf;
 347                 *treeblk = ret;
 348                 memset(buf, 0, V2_DQBLKSIZE);
 349                 newact = 1;
 350         }
 351         else {
 352                 if ((ret = read_blk(sb, dquot->dq_type, *treeblk, buf)) < 0) {
 353                         printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
 354                         goto out_buf;
 355                 }
 356         }
 357         ref = (__le32 *)buf;
 358         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 359         if (!newblk)
 360                 newson = 1;
 361         if (depth == V2_DQTREEDEPTH-1) {
 362 #ifdef __QUOTA_V2_PARANOIA
 363                 if (newblk) {
 364                         printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]));
 365                         ret = -EIO;
 366                         goto out_buf;
 367                 }
 368 #endif
 369                 newblk = find_free_dqentry(dquot, &ret);
 370         }
 371         else
 372                 ret = do_insert_tree(dquot, &newblk, depth+1);
 373         if (newson && ret >= 0) {
 374                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
 375                 ret = write_blk(sb, dquot->dq_type, *treeblk, buf);
 376         }
 377         else if (newact && ret < 0)
 378                 put_free_dqblk(sb, dquot->dq_type, buf, *treeblk);
 379 out_buf:
 380         freedqbuf(buf);
 381         return ret;
 382 }
 383
 384 /* Wrapper for inserting quota structure into tree */
 385 static inline int dq_insert_tree(struct dquot *dquot)
 386 {
 387         int tmp = V2_DQTREEOFF;
 388         return do_insert_tree(dquot, &tmp, 0);
 389 }
 390
 391 /*
 392  *      We don't have to be afraid of deadlocks as we never have quotas on quota files...
 393  */
 394 static int v2_write_dquot(struct dquot *dquot)
 395 {
 396         int type = dquot->dq_type;
 397         ssize_t ret;
 398         struct v2_disk_dqblk ddquot, empty;
 399
 400         /* dq_off is guarded by dqio_mutex */
 401         if (!dquot->dq_off)
 402                 if ((ret = dq_insert_tree(dquot)) < 0) {
 403                         printk(KERN_ERR "VFS: Error %zd occurred while creating quota.\n", ret);
 404                         return ret;
 405                 }
 406         spin_lock(&dq_data_lock);
 407         mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
 408         /* Argh... We may need to write structure full of zeroes but that would be
 409          * treated as an empty place by the rest of the code. Format change would
 410          * be definitely cleaner but the problems probably are not worth it */
 411         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 412         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 413                 ddquot.dqb_itime = cpu_to_le64(1);
 414         spin_unlock(&dq_data_lock);
 415         ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
 416               (char *)&ddquot, sizeof(struct v2_disk_dqblk), dquot->dq_off);
 417         if (ret != sizeof(struct v2_disk_dqblk)) {
 418                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
 419                 if (ret >= 0)
 420                         ret = -ENOSPC;
 421         }
 422         else
 423                 ret = 0;
 424         dqstats.writes++;
 425
 426         return ret;
 427 }
 428
 429 /* Free dquot entry in data block */
 430 static int free_dqentry(struct dquot *dquot, uint blk)
 431 {
 432         struct super_block *sb = dquot->dq_sb;
 433         int type = dquot->dq_type;
 434         struct v2_disk_dqdbheader *dh;
 435         dqbuf_t buf = getdqbuf();
 436         int ret = 0;
 437
 438         if (!buf)
 439                 return -ENOMEM;
 440         if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
 441                 printk(KERN_ERR "VFS: Quota structure has offset to other "
 442                   "block (%u) than it should (%u).\n", blk,
 443                   (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
 444                 goto out_buf;
 445         }
 446         if ((ret = read_blk(sb, type, blk, buf)) < 0) {
 447                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 448                 goto out_buf;
 449         }
 450         dh = (struct v2_disk_dqdbheader *)buf;
 451         le16_add_cpu(&dh->dqdh_entries, -1);
 452         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 453                 if ((ret = remove_free_dqentry(sb, type, buf, blk)) < 0 ||
 454                     (ret = put_free_dqblk(sb, type, buf, blk)) < 0) {
 455                         printk(KERN_ERR "VFS: Can't move quota data block (%u) "
 456                           "to free list.\n", blk);
 457                         goto out_buf;
 458                 }
 459         }
 460         else {
 461                 memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0,
 462                   sizeof(struct v2_disk_dqblk));
 463                 if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
 464                         /* Insert will write block itself */
 465                         if ((ret = insert_free_dqentry(sb, type, buf, blk)) < 0) {
 466                                 printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
 467                                 goto out_buf;
 468                         }
 469                 }
 470                 else
 471                         if ((ret = write_blk(sb, type, blk, buf)) < 0) {
 472                                 printk(KERN_ERR "VFS: Can't write quota data "
 473                                   "block %u\n", blk);
 474                                 goto out_buf;
 475                         }
 476         }
 477         dquot->dq_off = 0;      /* Quota is now unattached */
 478 out_buf:
 479         freedqbuf(buf);
 480         return ret;
 481 }
 482
 483 /* Remove reference to dquot from tree */
 484 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
 485 {
 486         struct super_block *sb = dquot->dq_sb;
 487         int type = dquot->dq_type;
 488         dqbuf_t buf = getdqbuf();
 489         int ret = 0;
 490         uint newblk;
 491         __le32 *ref = (__le32 *)buf;
 492
 493         if (!buf)
 494                 return -ENOMEM;
 495         if ((ret = read_blk(sb, type, *blk, buf)) < 0) {
 496                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 497                 goto out_buf;
 498         }
 499         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 500         if (depth == V2_DQTREEDEPTH-1) {
 501                 ret = free_dqentry(dquot, newblk);
 502                 newblk = 0;
 503         }
 504         else
 505                 ret = remove_tree(dquot, &newblk, depth+1);
 506         if (ret >= 0 && !newblk) {
 507                 int i;
 508                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
 509                 for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
 510                 /* Don't put the root block into the free block list */
 511                 if (i == V2_DQBLKSIZE && *blk != V2_DQTREEOFF) {
 512                         put_free_dqblk(sb, type, buf, *blk);
 513                         *blk = 0;
 514                 }
 515                 else
 516                         if ((ret = write_blk(sb, type, *blk, buf)) < 0)
 517                                 printk(KERN_ERR "VFS: Can't write quota tree "
 518                                   "block %u.\n", *blk);
 519         }
 520 out_buf:
 521         freedqbuf(buf);
 522         return ret;
 523 }
 524
 525 /* Delete dquot from tree */
 526 static int v2_delete_dquot(struct dquot *dquot)
 527 {
 528         uint tmp = V2_DQTREEOFF;
 529
 530         if (!dquot->dq_off)     /* Even not allocated? */
 531                 return 0;
 532         return remove_tree(dquot, &tmp, 0);
 533 }
 534
 535 /* Find entry in block */
 536 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
 537 {
 538         dqbuf_t buf = getdqbuf();
 539         loff_t ret = 0;
 540         int i;
 541         struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
 542
 543         if (!buf)
 544                 return -ENOMEM;
 545         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
 546                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 547                 goto out_buf;
 548         }
 549         if (dquot->dq_id)
 550                 for (i = 0; i < V2_DQSTRINBLK &&
 551                      le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
 552         else {  /* ID 0 as a bit more complicated searching... */
 553                 struct v2_disk_dqblk fakedquot;
 554
 555                 memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 556                 for (i = 0; i < V2_DQSTRINBLK; i++)
 557                         if (!le32_to_cpu(ddquot[i].dqb_id) &&
 558                             memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
 559                                 break;
 560         }
 561         if (i == V2_DQSTRINBLK) {
 562                 printk(KERN_ERR "VFS: Quota for id %u referenced "
 563                   "but not present.\n", dquot->dq_id);
 564                 ret = -EIO;
 565                 goto out_buf;
 566         }
 567         else
 568                 ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct
 569                   v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
 570 out_buf:
 571         freedqbuf(buf);
 572         return ret;
 573 }
 574
 575 /* Find entry for given id in the tree */
 576 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
 577 {
 578         dqbuf_t buf = getdqbuf();
 579         loff_t ret = 0;
 580         __le32 *ref = (__le32 *)buf;
 581
 582         if (!buf)
 583                 return -ENOMEM;
 584         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
 585                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 586                 goto out_buf;
 587         }
 588         ret = 0;
 589         blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 590         if (!blk)       /* No reference? */
 591                 goto out_buf;
 592         if (depth < V2_DQTREEDEPTH-1)
 593                 ret = find_tree_dqentry(dquot, blk, depth+1);
 594         else
 595                 ret = find_block_dqentry(dquot, blk);
 596 out_buf:
 597         freedqbuf(buf);
 598         return ret;
 599 }
 600
 601 /* Find entry for given id in the tree - wrapper function */
 602 static inline loff_t find_dqentry(struct dquot *dquot)
 603 {
 604         return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
 605 }
 606
 607 static int v2_read_dquot(struct dquot *dquot)
 608 {
 609         int type = dquot->dq_type;
 610         loff_t offset;
 611         struct v2_disk_dqblk ddquot, empty;
 612         int ret = 0;
 613
 614 #ifdef __QUOTA_V2_PARANOIA
 615         /* Invalidated quota? */
 616         if (!dquot->dq_sb || !sb_dqopt(dquot->dq_sb)->files[type]) {
 617                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 618                 return -EIO;
 619         }
 620 #endif
 621         offset = find_dqentry(dquot);
 622         if (offset <= 0) {      /* Entry not present? */
 623                 if (offset < 0)
 624                         printk(KERN_ERR "VFS: Can't read quota "
 625                           "structure for id %u.\n", dquot->dq_id);
 626                 dquot->dq_off = 0;
 627                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 628                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 629                 ret = offset;
 630         }
 631         else {
 632                 dquot->dq_off = offset;
 633                 if ((ret = dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type,
 634                     (char *)&ddquot, sizeof(struct v2_disk_dqblk), offset))
 635                     != sizeof(struct v2_disk_dqblk)) {
 636                         if (ret >= 0)
 637                                 ret = -EIO;
 638                         printk(KERN_ERR "VFS: Error while reading quota "
 639                           "structure for id %u.\n", dquot->dq_id);
 640                         memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
 641                 }
 642                 else {
 643                         ret = 0;
 644                         /* We need to escape back all-zero structure */
 645                         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 646                         empty.dqb_itime = cpu_to_le64(1);
 647                         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 648                                 ddquot.dqb_itime = 0;
 649                 }
 650                 disk2memdqb(&dquot->dq_dqb, &ddquot);
 651                 if (!dquot->dq_dqb.dqb_bhardlimit &&
 652                         !dquot->dq_dqb.dqb_bsoftlimit &&
 653                         !dquot->dq_dqb.dqb_ihardlimit &&
 654                         !dquot->dq_dqb.dqb_isoftlimit)
 655                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
 656         }
 657         dqstats.reads++;
 658
 659         return ret;
 660 }
 661
 662 /* Check whether dquot should not be deleted. We know we are
 663  * the only one operating on dquot (thanks to dq_lock) */
 664 static int v2_release_dquot(struct dquot *dquot)
 665 {
 666         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 667                 return v2_delete_dquot(dquot);
 668         return 0;
 669 }
 670
 671 static struct quota_format_ops v2_format_ops = {
 672         .check_quota_file       = v2_check_quota_file,
 673         .read_file_info         = v2_read_file_info,
 674         .write_file_info        = v2_write_file_info,
 675         .free_file_info         = NULL,
 676         .read_dqblk             = v2_read_dquot,
 677         .commit_dqblk           = v2_write_dquot,
 678         .release_dqblk          = v2_release_dquot,
 679 };
 680
 681 static struct quota_format_type v2_quota_format = {
 682         .qf_fmt_id      = QFMT_VFS_V0,
 683         .qf_ops         = &v2_format_ops,
 684         .qf_owner       = THIS_MODULE
 685 };
 686
 687 static int __init init_v2_quota_format(void)
 688 {
 689         return register_quota_format(&v2_quota_format);
 690 }
 691
 692 static void __exit exit_v2_quota_format(void)
 693 {
 694         unregister_quota_format(&v2_quota_format);
 695 }
 696
 697 module_init(init_v2_quota_format);
 698 module_exit(exit_v2_quota_format);