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   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 "quotaio_v2.h"
  18
  19 MODULE_AUTHOR("Jan Kara");
  20 MODULE_DESCRIPTION("Quota format v2 support");
  21 MODULE_LICENSE("GPL");
  22
  23 #define __QUOTA_V2_PARANOIA
  24
  25 typedef char *dqbuf_t;
  26
  27 #define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
  28 #define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))
  29
  30 #define QUOTABLOCK_BITS 10
  31 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
  32
  33 static inline qsize_t v2_stoqb(qsize_t space)
  34 {
  35         return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
  36 }
  37
  38 static inline qsize_t v2_qbtos(qsize_t blocks)
  39 {
  40         return blocks << QUOTABLOCK_BITS;
  41 }
  42
  43 /* Check whether given file is really vfsv0 quotafile */
  44 static int v2_check_quota_file(struct super_block *sb, int type)
  45 {
  46         struct v2_disk_dqheader dqhead;
  47         ssize_t size;
  48         static const uint quota_magics[] = V2_INITQMAGICS;
  49         static const uint quota_versions[] = V2_INITQVERSIONS;
  50
  51         size = sb->s_op->quota_read(sb, type, (char *)&dqhead, sizeof(struct v2_disk_dqheader), 0);
  52         if (size != sizeof(struct v2_disk_dqheader)) {
  53                 printk("quota_v2: failed read expected=%zd got=%zd\n",
  54                         sizeof(struct v2_disk_dqheader), size);
  55                 return 0;
  56         }
  57         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
  58             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
  59                 return 0;
  60         return 1;
  61 }
  62
  63 /* Read information header from quota file */
  64 static int v2_read_file_info(struct super_block *sb, int type)
  65 {
  66         struct v2_disk_dqinfo dinfo;
  67         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  68         ssize_t size;
  69
  70         size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
  71                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
  72         if (size != sizeof(struct v2_disk_dqinfo)) {
  73                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
  74                         sb->s_id);
  75                 return -1;
  76         }
  77         /* limits are stored as unsigned 32-bit data */
  78         info->dqi_maxblimit = 0xffffffff;
  79         info->dqi_maxilimit = 0xffffffff;
  80         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
  81         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
  82         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
  83         info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
  84         info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
  85         info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
  86         return 0;
  87 }
  88
  89 /* Write information header to quota file */
  90 static int v2_write_file_info(struct super_block *sb, int type)
  91 {
  92         struct v2_disk_dqinfo dinfo;
  93         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  94         ssize_t size;
  95
  96         spin_lock(&dq_data_lock);
  97         info->dqi_flags &= ~DQF_INFO_DIRTY;
  98         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
  99         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
 100         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
 101         spin_unlock(&dq_data_lock);
 102         dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
 103         dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 104         dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 105         size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
 106                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
 107         if (size != sizeof(struct v2_disk_dqinfo)) {
 108                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
 109                         sb->s_id);
 110                 return -1;
 111         }
 112         return 0;
 113 }
 114
 115 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
 116 {
 117         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
 118         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
 119         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
 120         m->dqb_itime = le64_to_cpu(d->dqb_itime);
 121         m->dqb_bhardlimit = v2_qbtos(le32_to_cpu(d->dqb_bhardlimit));
 122         m->dqb_bsoftlimit = v2_qbtos(le32_to_cpu(d->dqb_bsoftlimit));
 123         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
 124         m->dqb_btime = le64_to_cpu(d->dqb_btime);
 125 }
 126
 127 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
 128 {
 129         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
 130         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
 131         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
 132         d->dqb_itime = cpu_to_le64(m->dqb_itime);
 133         d->dqb_bhardlimit = cpu_to_le32(v2_stoqb(m->dqb_bhardlimit));
 134         d->dqb_bsoftlimit = cpu_to_le32(v2_stoqb(m->dqb_bsoftlimit));
 135         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
 136         d->dqb_btime = cpu_to_le64(m->dqb_btime);
 137         d->dqb_id = cpu_to_le32(id);
 138 }
 139
 140 static dqbuf_t getdqbuf(void)
 141 {
 142         dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_NOFS);
 143         if (!buf)
 144                 printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
 145         return buf;
 146 }
 147
 148 static inline void freedqbuf(dqbuf_t buf)
 149 {
 150         kfree(buf);
 151 }
 152
 153 static inline ssize_t read_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
 154 {
 155         memset(buf, 0, V2_DQBLKSIZE);
 156         return sb->s_op->quota_read(sb, type, (char *)buf,
 157                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
 158 }
 159
 160 static inline ssize_t write_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
 161 {
 162         return sb->s_op->quota_write(sb, type, (char *)buf,
 163                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
 164 }
 165
 166 /* Remove empty block from list and return it */
 167 static int get_free_dqblk(struct super_block *sb, int type)
 168 {
 169         dqbuf_t buf = getdqbuf();
 170         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 171         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 172         int ret, blk;
 173
 174         if (!buf)
 175                 return -ENOMEM;
 176         if (info->u.v2_i.dqi_free_blk) {
 177                 blk = info->u.v2_i.dqi_free_blk;
 178                 if ((ret = read_blk(sb, type, blk, buf)) < 0)
 179                         goto out_buf;
 180                 info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
 181         }
 182         else {
 183                 memset(buf, 0, V2_DQBLKSIZE);
 184                 /* Assure block allocation... */
 185                 if ((ret = write_blk(sb, type, info->u.v2_i.dqi_blocks, buf)) < 0)
 186                         goto out_buf;
 187                 blk = info->u.v2_i.dqi_blocks++;
 188         }
 189         mark_info_dirty(sb, type);
 190         ret = blk;
 191 out_buf:
 192         freedqbuf(buf);
 193         return ret;
 194 }
 195
 196 /* Insert empty block to the list */
 197 static int put_free_dqblk(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 198 {
 199         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 200         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 201         int err;
 202
 203         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 204         dh->dqdh_prev_free = cpu_to_le32(0);
 205         dh->dqdh_entries = cpu_to_le16(0);
 206         info->u.v2_i.dqi_free_blk = blk;
 207         mark_info_dirty(sb, type);
 208         /* Some strange block. We had better leave it... */
 209         if ((err = write_blk(sb, type, blk, buf)) < 0)
 210                 return err;
 211         return 0;
 212 }
 213
 214 /* Remove given block from the list of blocks with free entries */
 215 static int remove_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 216 {
 217         dqbuf_t tmpbuf = getdqbuf();
 218         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 219         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 220         uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
 221         int err;
 222
 223         if (!tmpbuf)
 224                 return -ENOMEM;
 225         if (nextblk) {
 226                 if ((err = read_blk(sb, type, nextblk, tmpbuf)) < 0)
 227                         goto out_buf;
 228                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
 229                 if ((err = write_blk(sb, type, nextblk, tmpbuf)) < 0)
 230                         goto out_buf;
 231         }
 232         if (prevblk) {
 233                 if ((err = read_blk(sb, type, prevblk, tmpbuf)) < 0)
 234                         goto out_buf;
 235                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
 236                 if ((err = write_blk(sb, type, prevblk, tmpbuf)) < 0)
 237                         goto out_buf;
 238         }
 239         else {
 240                 info->u.v2_i.dqi_free_entry = nextblk;
 241                 mark_info_dirty(sb, type);
 242         }
 243         freedqbuf(tmpbuf);
 244         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 245         /* No matter whether write succeeds block is out of list */
 246         if (write_blk(sb, type, blk, buf) < 0)
 247                 printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
 248         return 0;
 249 out_buf:
 250         freedqbuf(tmpbuf);
 251         return err;
 252 }
 253
 254 /* Insert given block to the beginning of list with free entries */
 255 static int insert_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
 256 {
 257         dqbuf_t tmpbuf = getdqbuf();
 258         struct mem_dqinfo *info = sb_dqinfo(sb, type);
 259         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 260         int err;
 261
 262         if (!tmpbuf)
 263                 return -ENOMEM;
 264         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 265         dh->dqdh_prev_free = cpu_to_le32(0);
 266         if ((err = write_blk(sb, type, blk, buf)) < 0)
 267                 goto out_buf;
 268         if (info->u.v2_i.dqi_free_entry) {
 269                 if ((err = read_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 270                         goto out_buf;
 271                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
 272                 if ((err = write_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 273                         goto out_buf;
 274         }
 275         freedqbuf(tmpbuf);
 276         info->u.v2_i.dqi_free_entry = blk;
 277         mark_info_dirty(sb, type);
 278         return 0;
 279 out_buf:
 280         freedqbuf(tmpbuf);
 281         return err;
 282 }
 283
 284 /* Find space for dquot */
 285 static uint find_free_dqentry(struct dquot *dquot, int *err)
 286 {
 287         struct super_block *sb = dquot->dq_sb;
 288         struct mem_dqinfo *info = sb_dqopt(sb)->info+dquot->dq_type;
 289         uint blk, i;
 290         struct v2_disk_dqdbheader *dh;
 291         struct v2_disk_dqblk *ddquot;
 292         struct v2_disk_dqblk fakedquot;
 293         dqbuf_t buf;
 294
 295         *err = 0;
 296         if (!(buf = getdqbuf())) {
 297                 *err = -ENOMEM;
 298                 return 0;
 299         }
 300         dh = (struct v2_disk_dqdbheader *)buf;
 301         ddquot = GETENTRIES(buf);
 302         if (info->u.v2_i.dqi_free_entry) {
 303                 blk = info->u.v2_i.dqi_free_entry;
 304                 if ((*err = read_blk(sb, dquot->dq_type, blk, buf)) < 0)
 305                         goto out_buf;
 306         }
 307         else {
 308                 blk = get_free_dqblk(sb, dquot->dq_type);
 309                 if ((int)blk < 0) {
 310                         *err = blk;
 311                         freedqbuf(buf);
 312                         return 0;
 313                 }
 314                 memset(buf, 0, V2_DQBLKSIZE);
 315                 /* This is enough as block is already zeroed and entry list is empty... */
 316                 info->u.v2_i.dqi_free_entry = blk;
 317                 mark_info_dirty(sb, dquot->dq_type);
 318         }
 319         if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
 320                 if ((*err = remove_free_dqentry(sb, dquot->dq_type, buf, blk)) < 0) {
 321                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
 322                         goto out_buf;
 323                 }
 324         le16_add_cpu(&dh->dqdh_entries, 1);
 325         memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 326         /* Find free structure in block */
 327         for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
 328 #ifdef __QUOTA_V2_PARANOIA
 329         if (i == V2_DQSTRINBLK) {
 330                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
 331                 *err = -EIO;
 332                 goto out_buf;
 333         }
 334 #endif
 335         if ((*err = write_blk(sb, dquot->dq_type, blk, buf)) < 0) {
 336                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
 337                 goto out_buf;
 338         }
 339         dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
 340         freedqbuf(buf);
 341         return blk;
 342 out_buf:
 343         freedqbuf(buf);
 344         return 0;
 345 }
 346
 347 /* Insert reference to structure into the trie */
 348 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
 349 {
 350         struct super_block *sb = dquot->dq_sb;
 351         dqbuf_t buf;
 352         int ret = 0, newson = 0, newact = 0;
 353         __le32 *ref;
 354         uint newblk;
 355
 356         if (!(buf = getdqbuf()))
 357                 return -ENOMEM;
 358         if (!*treeblk) {
 359                 ret = get_free_dqblk(sb, dquot->dq_type);
 360                 if (ret < 0)
 361                         goto out_buf;
 362                 *treeblk = ret;
 363                 memset(buf, 0, V2_DQBLKSIZE);
 364                 newact = 1;
 365         }
 366         else {
 367                 if ((ret = read_blk(sb, dquot->dq_type, *treeblk, buf)) < 0) {
 368                         printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
 369                         goto out_buf;
 370                 }
 371         }
 372         ref = (__le32 *)buf;
 373         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 374         if (!newblk)
 375                 newson = 1;
 376         if (depth == V2_DQTREEDEPTH-1) {
 377 #ifdef __QUOTA_V2_PARANOIA
 378                 if (newblk) {
 379                         printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]));
 380                         ret = -EIO;
 381                         goto out_buf;
 382                 }
 383 #endif
 384                 newblk = find_free_dqentry(dquot, &ret);
 385         }
 386         else
 387                 ret = do_insert_tree(dquot, &newblk, depth+1);
 388         if (newson && ret >= 0) {
 389                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
 390                 ret = write_blk(sb, dquot->dq_type, *treeblk, buf);
 391         }
 392         else if (newact && ret < 0)
 393                 put_free_dqblk(sb, dquot->dq_type, buf, *treeblk);
 394 out_buf:
 395         freedqbuf(buf);
 396         return ret;
 397 }
 398
 399 /* Wrapper for inserting quota structure into tree */
 400 static inline int dq_insert_tree(struct dquot *dquot)
 401 {
 402         int tmp = V2_DQTREEOFF;
 403         return do_insert_tree(dquot, &tmp, 0);
 404 }
 405
 406 /*
 407  *      We don't have to be afraid of deadlocks as we never have quotas on quota files...
 408  */
 409 static int v2_write_dquot(struct dquot *dquot)
 410 {
 411         int type = dquot->dq_type;
 412         ssize_t ret;
 413         struct v2_disk_dqblk ddquot, empty;
 414
 415         /* dq_off is guarded by dqio_mutex */
 416         if (!dquot->dq_off)
 417                 if ((ret = dq_insert_tree(dquot)) < 0) {
 418                         printk(KERN_ERR "VFS: Error %zd occurred while creating quota.\n", ret);
 419                         return ret;
 420                 }
 421         spin_lock(&dq_data_lock);
 422         mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
 423         /* Argh... We may need to write structure full of zeroes but that would be
 424          * treated as an empty place by the rest of the code. Format change would
 425          * be definitely cleaner but the problems probably are not worth it */
 426         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 427         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 428                 ddquot.dqb_itime = cpu_to_le64(1);
 429         spin_unlock(&dq_data_lock);
 430         ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
 431               (char *)&ddquot, sizeof(struct v2_disk_dqblk), dquot->dq_off);
 432         if (ret != sizeof(struct v2_disk_dqblk)) {
 433                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
 434                 if (ret >= 0)
 435                         ret = -ENOSPC;
 436         }
 437         else
 438                 ret = 0;
 439         dqstats.writes++;
 440
 441         return ret;
 442 }
 443
 444 /* Free dquot entry in data block */
 445 static int free_dqentry(struct dquot *dquot, uint blk)
 446 {
 447         struct super_block *sb = dquot->dq_sb;
 448         int type = dquot->dq_type;
 449         struct v2_disk_dqdbheader *dh;
 450         dqbuf_t buf = getdqbuf();
 451         int ret = 0;
 452
 453         if (!buf)
 454                 return -ENOMEM;
 455         if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
 456                 printk(KERN_ERR "VFS: Quota structure has offset to other "
 457                   "block (%u) than it should (%u).\n", blk,
 458                   (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
 459                 goto out_buf;
 460         }
 461         if ((ret = read_blk(sb, type, blk, buf)) < 0) {
 462                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 463                 goto out_buf;
 464         }
 465         dh = (struct v2_disk_dqdbheader *)buf;
 466         le16_add_cpu(&dh->dqdh_entries, -1);
 467         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 468                 if ((ret = remove_free_dqentry(sb, type, buf, blk)) < 0 ||
 469                     (ret = put_free_dqblk(sb, type, buf, blk)) < 0) {
 470                         printk(KERN_ERR "VFS: Can't move quota data block (%u) "
 471                           "to free list.\n", blk);
 472                         goto out_buf;
 473                 }
 474         }
 475         else {
 476                 memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0,
 477                   sizeof(struct v2_disk_dqblk));
 478                 if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
 479                         /* Insert will write block itself */
 480                         if ((ret = insert_free_dqentry(sb, type, buf, blk)) < 0) {
 481                                 printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
 482                                 goto out_buf;
 483                         }
 484                 }
 485                 else
 486                         if ((ret = write_blk(sb, type, blk, buf)) < 0) {
 487                                 printk(KERN_ERR "VFS: Can't write quota data "
 488                                   "block %u\n", blk);
 489                                 goto out_buf;
 490                         }
 491         }
 492         dquot->dq_off = 0;      /* Quota is now unattached */
 493 out_buf:
 494         freedqbuf(buf);
 495         return ret;
 496 }
 497
 498 /* Remove reference to dquot from tree */
 499 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
 500 {
 501         struct super_block *sb = dquot->dq_sb;
 502         int type = dquot->dq_type;
 503         dqbuf_t buf = getdqbuf();
 504         int ret = 0;
 505         uint newblk;
 506         __le32 *ref = (__le32 *)buf;
 507
 508         if (!buf)
 509                 return -ENOMEM;
 510         if ((ret = read_blk(sb, type, *blk, buf)) < 0) {
 511                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 512                 goto out_buf;
 513         }
 514         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 515         if (depth == V2_DQTREEDEPTH-1) {
 516                 ret = free_dqentry(dquot, newblk);
 517                 newblk = 0;
 518         }
 519         else
 520                 ret = remove_tree(dquot, &newblk, depth+1);
 521         if (ret >= 0 && !newblk) {
 522                 int i;
 523                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
 524                 for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
 525                 /* Don't put the root block into the free block list */
 526                 if (i == V2_DQBLKSIZE && *blk != V2_DQTREEOFF) {
 527                         put_free_dqblk(sb, type, buf, *blk);
 528                         *blk = 0;
 529                 }
 530                 else
 531                         if ((ret = write_blk(sb, type, *blk, buf)) < 0)
 532                                 printk(KERN_ERR "VFS: Can't write quota tree "
 533                                   "block %u.\n", *blk);
 534         }
 535 out_buf:
 536         freedqbuf(buf);
 537         return ret;
 538 }
 539
 540 /* Delete dquot from tree */
 541 static int v2_delete_dquot(struct dquot *dquot)
 542 {
 543         uint tmp = V2_DQTREEOFF;
 544
 545         if (!dquot->dq_off)     /* Even not allocated? */
 546                 return 0;
 547         return remove_tree(dquot, &tmp, 0);
 548 }
 549
 550 /* Find entry in block */
 551 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
 552 {
 553         dqbuf_t buf = getdqbuf();
 554         loff_t ret = 0;
 555         int i;
 556         struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
 557
 558         if (!buf)
 559                 return -ENOMEM;
 560         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
 561                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 562                 goto out_buf;
 563         }
 564         if (dquot->dq_id)
 565                 for (i = 0; i < V2_DQSTRINBLK &&
 566                      le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
 567         else {  /* ID 0 as a bit more complicated searching... */
 568                 struct v2_disk_dqblk fakedquot;
 569
 570                 memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 571                 for (i = 0; i < V2_DQSTRINBLK; i++)
 572                         if (!le32_to_cpu(ddquot[i].dqb_id) &&
 573                             memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
 574                                 break;
 575         }
 576         if (i == V2_DQSTRINBLK) {
 577                 printk(KERN_ERR "VFS: Quota for id %u referenced "
 578                   "but not present.\n", dquot->dq_id);
 579                 ret = -EIO;
 580                 goto out_buf;
 581         }
 582         else
 583                 ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct
 584                   v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
 585 out_buf:
 586         freedqbuf(buf);
 587         return ret;
 588 }
 589
 590 /* Find entry for given id in the tree */
 591 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
 592 {
 593         dqbuf_t buf = getdqbuf();
 594         loff_t ret = 0;
 595         __le32 *ref = (__le32 *)buf;
 596
 597         if (!buf)
 598                 return -ENOMEM;
 599         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
 600                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 601                 goto out_buf;
 602         }
 603         ret = 0;
 604         blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 605         if (!blk)       /* No reference? */
 606                 goto out_buf;
 607         if (depth < V2_DQTREEDEPTH-1)
 608                 ret = find_tree_dqentry(dquot, blk, depth+1);
 609         else
 610                 ret = find_block_dqentry(dquot, blk);
 611 out_buf:
 612         freedqbuf(buf);
 613         return ret;
 614 }
 615
 616 /* Find entry for given id in the tree - wrapper function */
 617 static inline loff_t find_dqentry(struct dquot *dquot)
 618 {
 619         return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
 620 }
 621
 622 static int v2_read_dquot(struct dquot *dquot)
 623 {
 624         int type = dquot->dq_type;
 625         loff_t offset;
 626         struct v2_disk_dqblk ddquot, empty;
 627         int ret = 0;
 628
 629 #ifdef __QUOTA_V2_PARANOIA
 630         /* Invalidated quota? */
 631         if (!dquot->dq_sb || !sb_dqopt(dquot->dq_sb)->files[type]) {
 632                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 633                 return -EIO;
 634         }
 635 #endif
 636         offset = find_dqentry(dquot);
 637         if (offset <= 0) {      /* Entry not present? */
 638                 if (offset < 0)
 639                         printk(KERN_ERR "VFS: Can't read quota "
 640                           "structure for id %u.\n", dquot->dq_id);
 641                 dquot->dq_off = 0;
 642                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 643                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 644                 ret = offset;
 645         }
 646         else {
 647                 dquot->dq_off = offset;
 648                 if ((ret = dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type,
 649                     (char *)&ddquot, sizeof(struct v2_disk_dqblk), offset))
 650                     != sizeof(struct v2_disk_dqblk)) {
 651                         if (ret >= 0)
 652                                 ret = -EIO;
 653                         printk(KERN_ERR "VFS: Error while reading quota "
 654                           "structure for id %u.\n", dquot->dq_id);
 655                         memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
 656                 }
 657                 else {
 658                         ret = 0;
 659                         /* We need to escape back all-zero structure */
 660                         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 661                         empty.dqb_itime = cpu_to_le64(1);
 662                         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 663                                 ddquot.dqb_itime = 0;
 664                 }
 665                 disk2memdqb(&dquot->dq_dqb, &ddquot);
 666                 if (!dquot->dq_dqb.dqb_bhardlimit &&
 667                         !dquot->dq_dqb.dqb_bsoftlimit &&
 668                         !dquot->dq_dqb.dqb_ihardlimit &&
 669                         !dquot->dq_dqb.dqb_isoftlimit)
 670                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
 671         }
 672         dqstats.reads++;
 673
 674         return ret;
 675 }
 676
 677 /* Check whether dquot should not be deleted. We know we are
 678  * the only one operating on dquot (thanks to dq_lock) */
 679 static int v2_release_dquot(struct dquot *dquot)
 680 {
 681         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 682                 return v2_delete_dquot(dquot);
 683         return 0;
 684 }
 685
 686 static struct quota_format_ops v2_format_ops = {
 687         .check_quota_file       = v2_check_quota_file,
 688         .read_file_info         = v2_read_file_info,
 689         .write_file_info        = v2_write_file_info,
 690         .free_file_info         = NULL,
 691         .read_dqblk             = v2_read_dquot,
 692         .commit_dqblk           = v2_write_dquot,
 693         .release_dqblk          = v2_release_dquot,
 694 };
 695
 696 static struct quota_format_type v2_quota_format = {
 697         .qf_fmt_id      = QFMT_VFS_V0,
 698         .qf_ops         = &v2_format_ops,
 699         .qf_owner       = THIS_MODULE
 700 };
 701
 702 static int __init init_v2_quota_format(void)
 703 {
 704         return register_quota_format(&v2_quota_format);
 705 }
 706
 707 static void __exit exit_v2_quota_format(void)
 708 {
 709         unregister_quota_format(&v2_quota_format);
 710 }
 711
 712 module_init(init_v2_quota_format);
 713 module_exit(exit_v2_quota_format);