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