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