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/dqblk_v2.h>
   8 #include <linux/quotaio_v2.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13
  14 #include <asm/byteorder.h>
  15 #include <asm/uaccess.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         struct file *f = sb_dqopt(sb)->files[type];
  33         mm_segment_t fs;
  34         ssize_t size;
  35         loff_t offset = 0;
  36         static const uint quota_magics[] = V2_INITQMAGICS;
  37         static const uint quota_versions[] = V2_INITQVERSIONS;
  38
  39         fs = get_fs();
  40         set_fs(KERNEL_DS);
  41         size = f->f_op->read(f, (char *)&dqhead, sizeof(struct v2_disk_dqheader), &offset);
  42         set_fs(fs);
  43         if (size != sizeof(struct v2_disk_dqheader))
  44                 return 0;
  45         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
  46             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
  47                 return 0;
  48         return 1;
  49 }
  50
  51 /* Read information header from quota file */
  52 static int v2_read_file_info(struct super_block *sb, int type)
  53 {
  54         mm_segment_t fs;
  55         struct v2_disk_dqinfo dinfo;
  56         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  57         struct file *f = sb_dqopt(sb)->files[type];
  58         ssize_t size;
  59         loff_t offset = V2_DQINFOOFF;
  60
  61         fs = get_fs();
  62         set_fs(KERNEL_DS);
  63         size = f->f_op->read(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
  64         set_fs(fs);
  65         if (size != sizeof(struct v2_disk_dqinfo)) {
  66                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
  67                         kdevname(f->f_dentry->d_sb->s_dev));
  68                 return -1;
  69         }
  70         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
  71         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
  72         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
  73         info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
  74         info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
  75         info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
  76         return 0;
  77 }
  78
  79 /* Write information header to quota file */
  80 static int v2_write_file_info(struct super_block *sb, int type)
  81 {
  82         mm_segment_t fs;
  83         struct v2_disk_dqinfo dinfo;
  84         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  85         struct file *f = sb_dqopt(sb)->files[type];
  86         ssize_t size;
  87         loff_t offset = V2_DQINFOOFF;
  88
  89         info->dqi_flags &= ~DQF_INFO_DIRTY;
  90         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
  91         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
  92         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
  93         dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
  94         dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
  95         dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
  96         fs = get_fs();
  97         set_fs(KERNEL_DS);
  98         size = f->f_op->write(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
  99         set_fs(fs);
 100         if (size != sizeof(struct v2_disk_dqinfo)) {
 101                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
 102                         kdevname(f->f_dentry->d_sb->s_dev));
 103                 return -1;
 104         }
 105         return 0;
 106 }
 107
 108 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
 109 {
 110         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
 111         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
 112         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
 113         m->dqb_itime = le64_to_cpu(d->dqb_itime);
 114         m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
 115         m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
 116         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
 117         m->dqb_btime = le64_to_cpu(d->dqb_btime);
 118 }
 119
 120 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
 121 {
 122         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
 123         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
 124         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
 125         d->dqb_itime = cpu_to_le64(m->dqb_itime);
 126         d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
 127         d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
 128         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
 129         d->dqb_btime = cpu_to_le64(m->dqb_btime);
 130         d->dqb_id = cpu_to_le32(id);
 131 }
 132
 133 static dqbuf_t getdqbuf(void)
 134 {
 135         dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_KERNEL);
 136         if (!buf)
 137                 printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
 138         return buf;
 139 }
 140
 141 static inline void freedqbuf(dqbuf_t buf)
 142 {
 143         kfree(buf);
 144 }
 145
 146 static ssize_t read_blk(struct file *filp, uint blk, dqbuf_t buf)
 147 {
 148         mm_segment_t fs;
 149         ssize_t ret;
 150         loff_t offset = blk<<V2_DQBLKSIZE_BITS;
 151
 152         memset(buf, 0, V2_DQBLKSIZE);
 153         fs = get_fs();
 154         set_fs(KERNEL_DS);
 155         ret = filp->f_op->read(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 156         set_fs(fs);
 157         return ret;
 158 }
 159
 160 static ssize_t write_blk(struct file *filp, uint blk, dqbuf_t buf)
 161 {
 162         mm_segment_t fs;
 163         ssize_t ret;
 164         loff_t offset = blk<<V2_DQBLKSIZE_BITS;
 165
 166         fs = get_fs();
 167         set_fs(KERNEL_DS);
 168         ret = filp->f_op->write(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 169         set_fs(fs);
 170         return ret;
 171
 172 }
 173
 174 /* Remove empty block from list and return it */
 175 static int get_free_dqblk(struct file *filp, struct mem_dqinfo *info)
 176 {
 177         dqbuf_t buf = getdqbuf();
 178         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 179         int ret, blk;
 180
 181         if (!buf)
 182                 return -ENOMEM;
 183         if (info->u.v2_i.dqi_free_blk) {
 184                 blk = info->u.v2_i.dqi_free_blk;
 185                 if ((ret = read_blk(filp, blk, buf)) < 0)
 186                         goto out_buf;
 187                 info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
 188         }
 189         else {
 190                 memset(buf, 0, V2_DQBLKSIZE);
 191                 if ((ret = write_blk(filp, info->u.v2_i.dqi_blocks, buf)) < 0)  /* Assure block allocation... */
 192                         goto out_buf;
 193                 blk = info->u.v2_i.dqi_blocks++;
 194         }
 195         mark_info_dirty(info);
 196         ret = blk;
 197 out_buf:
 198         freedqbuf(buf);
 199         return ret;
 200 }
 201
 202 /* Insert empty block to the list */
 203 static int put_free_dqblk(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 204 {
 205         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 206         int err;
 207
 208         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 209         dh->dqdh_prev_free = cpu_to_le32(0);
 210         dh->dqdh_entries = cpu_to_le16(0);
 211         info->u.v2_i.dqi_free_blk = blk;
 212         mark_info_dirty(info);
 213         if ((err = write_blk(filp, blk, buf)) < 0)      /* Some strange block. We had better leave it... */
 214                 return err;
 215         return 0;
 216 }
 217
 218 /* Remove given block from the list of blocks with free entries */
 219 static int remove_free_dqentry(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 220 {
 221         dqbuf_t tmpbuf = getdqbuf();
 222         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 223         uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
 224         int err;
 225
 226         if (!tmpbuf)
 227                 return -ENOMEM;
 228         if (nextblk) {
 229                 if ((err = read_blk(filp, nextblk, tmpbuf)) < 0)
 230                         goto out_buf;
 231                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
 232                 if ((err = write_blk(filp, nextblk, tmpbuf)) < 0)
 233                         goto out_buf;
 234         }
 235         if (prevblk) {
 236                 if ((err = read_blk(filp, prevblk, tmpbuf)) < 0)
 237                         goto out_buf;
 238                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
 239                 if ((err = write_blk(filp, prevblk, tmpbuf)) < 0)
 240                         goto out_buf;
 241         }
 242         else {
 243                 info->u.v2_i.dqi_free_entry = nextblk;
 244                 mark_info_dirty(info);
 245         }
 246         freedqbuf(tmpbuf);
 247         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 248         if (write_blk(filp, blk, buf) < 0)      /* No matter whether write succeeds block is out of list */
 249                 printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
 250         return 0;
 251 out_buf:
 252         freedqbuf(tmpbuf);
 253         return err;
 254 }
 255
 256 /* Insert given block to the beginning of list with free entries */
 257 static int insert_free_dqentry(struct file *filp, struct mem_dqinfo *info, dqbuf_t buf, uint blk)
 258 {
 259         dqbuf_t tmpbuf = getdqbuf();
 260         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 261         int err;
 262
 263         if (!tmpbuf)
 264                 return -ENOMEM;
 265         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 266         dh->dqdh_prev_free = cpu_to_le32(0);
 267         if ((err = write_blk(filp, blk, buf)) < 0)
 268                 goto out_buf;
 269         if (info->u.v2_i.dqi_free_entry) {
 270                 if ((err = read_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 271                         goto out_buf;
 272                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
 273                 if ((err = write_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 274                         goto out_buf;
 275         }
 276         freedqbuf(tmpbuf);
 277         info->u.v2_i.dqi_free_entry = blk;
 278         mark_info_dirty(info);
 279         return 0;
 280 out_buf:
 281         freedqbuf(tmpbuf);
 282         return err;
 283 }
 284
 285 /* Find space for dquot */
 286 static uint find_free_dqentry(struct dquot *dquot, int *err)
 287 {
 288         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 289         struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info+dquot->dq_type;
 290         uint blk, i;
 291         struct v2_disk_dqdbheader *dh;
 292         struct v2_disk_dqblk *ddquot;
 293         struct v2_disk_dqblk fakedquot;
 294         dqbuf_t buf;
 295
 296         *err = 0;
 297         if (!(buf = getdqbuf())) {
 298                 *err = -ENOMEM;
 299                 return 0;
 300         }
 301         dh = (struct v2_disk_dqdbheader *)buf;
 302         ddquot = GETENTRIES(buf);
 303         if (info->u.v2_i.dqi_free_entry) {
 304                 blk = info->u.v2_i.dqi_free_entry;
 305                 if ((*err = read_blk(filp, blk, buf)) < 0)
 306                         goto out_buf;
 307         }
 308         else {
 309                 blk = get_free_dqblk(filp, info);
 310                 if ((int)blk < 0) {
 311                         *err = blk;
 312                         return 0;
 313                 }
 314                 memset(buf, 0, V2_DQBLKSIZE);
 315                 info->u.v2_i.dqi_free_entry = blk;      /* This is enough as block is already zeroed and entry list is empty... */
 316                 mark_info_dirty(info);
 317         }
 318         if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
 319                 if ((*err = remove_free_dqentry(filp, info, buf, blk)) < 0) {
 320                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
 321                         goto out_buf;
 322                 }
 323         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
 324         memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 325         /* Find free structure in block */
 326         for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
 327 #ifdef __QUOTA_V2_PARANOIA
 328         if (i == V2_DQSTRINBLK) {
 329                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
 330                 *err = -EIO;
 331                 goto out_buf;
 332         }
 333 #endif
 334         if ((*err = write_blk(filp, blk, buf)) < 0) {
 335                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
 336                 goto out_buf;
 337         }
 338         dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
 339         freedqbuf(buf);
 340         return blk;
 341 out_buf:
 342         freedqbuf(buf);
 343         return 0;
 344 }
 345
 346 /* Insert reference to structure into the trie */
 347 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
 348 {
 349         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 350         struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 351         dqbuf_t buf;
 352         int ret = 0, newson = 0, newact = 0;
 353         u32 *ref;
 354         uint newblk;
 355
 356         if (!(buf = getdqbuf()))
 357                 return -ENOMEM;
 358         if (!*treeblk) {
 359                 ret = get_free_dqblk(filp, info);
 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(filp, *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 = (u32 *)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", 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(filp, *treeblk, buf);
 391         }
 392         else if (newact && ret < 0)
 393                 put_free_dqblk(filp, info, 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         struct file *filp;
 413         mm_segment_t fs;
 414         loff_t offset;
 415         ssize_t ret;
 416         struct v2_disk_dqblk ddquot;
 417
 418         if (!dquot->dq_off)
 419                 if ((ret = dq_insert_tree(dquot)) < 0) {
 420                         printk(KERN_ERR "VFS: Error %d occured while creating quota.\n", ret);
 421                         return ret;
 422                 }
 423         filp = sb_dqopt(dquot->dq_sb)->files[type];
 424         offset = dquot->dq_off;
 425         mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
 426         fs = get_fs();
 427         set_fs(KERNEL_DS);
 428         ret = filp->f_op->write(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset);
 429         set_fs(fs);
 430         if (ret != sizeof(struct v2_disk_dqblk)) {
 431                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", kdevname(dquot->dq_dev));
 432                 if (ret >= 0)
 433                         ret = -ENOSPC;
 434         }
 435         else
 436                 ret = 0;
 437         dqstats.writes++;
 438         return ret;
 439 }
 440
 441 /* Free dquot entry in data block */
 442 static int free_dqentry(struct dquot *dquot, uint blk)
 443 {
 444         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 445         struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 446         struct v2_disk_dqdbheader *dh;
 447         dqbuf_t buf = getdqbuf();
 448         int ret = 0;
 449
 450         if (!buf)
 451                 return -ENOMEM;
 452         if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
 453                 printk(KERN_ERR "VFS: Quota structure has offset to other block (%u) than it should (%u).\n", blk, (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
 454                 goto out_buf;
 455         }
 456         if ((ret = read_blk(filp, blk, buf)) < 0) {
 457                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 458                 goto out_buf;
 459         }
 460         dh = (struct v2_disk_dqdbheader *)buf;
 461         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
 462         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 463                 if ((ret = remove_free_dqentry(filp, info, buf, blk)) < 0 ||
 464                     (ret = put_free_dqblk(filp, info, buf, blk)) < 0) {
 465                         printk(KERN_ERR "VFS: Can't move quota data block (%u) to free list.\n", blk);
 466                         goto out_buf;
 467                 }
 468         }
 469         else {
 470                 memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0, sizeof(struct v2_disk_dqblk));
 471                 if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
 472                         /* Insert will write block itself */
 473                         if ((ret = insert_free_dqentry(filp, info, buf, blk)) < 0) {
 474                                 printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
 475                                 goto out_buf;
 476                         }
 477                 }
 478                 else
 479                         if ((ret = write_blk(filp, blk, buf)) < 0) {
 480                                 printk(KERN_ERR "VFS: Can't write quota data block %u\n", blk);
 481                                 goto out_buf;
 482                         }
 483         }
 484         dquot->dq_off = 0;      /* Quota is now unattached */
 485 out_buf:
 486         freedqbuf(buf);
 487         return ret;
 488 }
 489
 490 /* Remove reference to dquot from tree */
 491 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
 492 {
 493         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 494         struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info + dquot->dq_type;
 495         dqbuf_t buf = getdqbuf();
 496         int ret = 0;
 497         uint newblk;
 498         u32 *ref = (u32 *)buf;
 499
 500         if (!buf)
 501                 return -ENOMEM;
 502         if ((ret = read_blk(filp, *blk, buf)) < 0) {
 503                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 504                 goto out_buf;
 505         }
 506         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 507         if (depth == V2_DQTREEDEPTH-1) {
 508                 ret = free_dqentry(dquot, newblk);
 509                 newblk = 0;
 510         }
 511         else
 512                 ret = remove_tree(dquot, &newblk, depth+1);
 513         if (ret >= 0 && !newblk) {
 514                 int i;
 515                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
 516                 for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
 517                 if (i == V2_DQBLKSIZE) {
 518                         put_free_dqblk(filp, info, buf, *blk);
 519                         *blk = 0;
 520                 }
 521                 else
 522                         if ((ret = write_blk(filp, *blk, buf)) < 0)
 523                                 printk(KERN_ERR "VFS: Can't write quota tree block %u.\n", *blk);
 524         }
 525 out_buf:
 526         freedqbuf(buf);
 527         return ret;
 528 }
 529
 530 /* Delete dquot from tree */
 531 static int v2_delete_dquot(struct dquot *dquot)
 532 {
 533         uint tmp = V2_DQTREEOFF;
 534
 535         if (!dquot->dq_off)     /* Even not allocated? */
 536                 return 0;
 537         return remove_tree(dquot, &tmp, 0);
 538 }
 539
 540 /* Find entry in block */
 541 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
 542 {
 543         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 544         dqbuf_t buf = getdqbuf();
 545         loff_t ret = 0;
 546         int i;
 547         struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
 548
 549         if (!buf)
 550                 return -ENOMEM;
 551         if ((ret = read_blk(filp, blk, buf)) < 0) {
 552                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 553                 goto out_buf;
 554         }
 555         if (dquot->dq_id)
 556                 for (i = 0; i < V2_DQSTRINBLK && le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
 557         else {  /* ID 0 as a bit more complicated searching... */
 558                 struct v2_disk_dqblk fakedquot;
 559
 560                 memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 561                 for (i = 0; i < V2_DQSTRINBLK; i++)
 562                         if (!le32_to_cpu(ddquot[i].dqb_id) && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
 563                                 break;
 564         }
 565         if (i == V2_DQSTRINBLK) {
 566                 printk(KERN_ERR "VFS: Quota for id %u referenced but not present.\n", dquot->dq_id);
 567                 ret = -EIO;
 568                 goto out_buf;
 569         }
 570         else
 571                 ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
 572 out_buf:
 573         freedqbuf(buf);
 574         return ret;
 575 }
 576
 577 /* Find entry for given id in the tree */
 578 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
 579 {
 580         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 581         dqbuf_t buf = getdqbuf();
 582         loff_t ret = 0;
 583         u32 *ref = (u32 *)buf;
 584
 585         if (!buf)
 586                 return -ENOMEM;
 587         if ((ret = read_blk(filp, blk, buf)) < 0) {
 588                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 589                 goto out_buf;
 590         }
 591         ret = 0;
 592         blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 593         if (!blk)       /* No reference? */
 594                 goto out_buf;
 595         if (depth < V2_DQTREEDEPTH-1)
 596                 ret = find_tree_dqentry(dquot, blk, depth+1);
 597         else
 598                 ret = find_block_dqentry(dquot, blk);
 599 out_buf:
 600         freedqbuf(buf);
 601         return ret;
 602 }
 603
 604 /* Find entry for given id in the tree - wrapper function */
 605 static inline loff_t find_dqentry(struct dquot *dquot)
 606 {
 607         return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
 608 }
 609
 610 static int v2_read_dquot(struct dquot *dquot)
 611 {
 612         int type = dquot->dq_type;
 613         struct file *filp;
 614         mm_segment_t fs;
 615         loff_t offset;
 616         struct v2_disk_dqblk ddquot;
 617         int ret = 0;
 618
 619         filp = sb_dqopt(dquot->dq_sb)->files[type];
 620
 621 #ifdef __QUOTA_V2_PARANOIA
 622         if (!filp || !dquot->dq_sb) {   /* Invalidated quota? */
 623                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 624                 return -EIO;
 625         }
 626 #endif
 627         offset = find_dqentry(dquot);
 628         if (offset <= 0) {      /* Entry not present? */
 629                 if (offset < 0)
 630                         printk(KERN_ERR "VFS: Can't read quota structure for id %u.\n", dquot->dq_id);
 631                 dquot->dq_off = 0;
 632                 dquot->dq_flags |= DQ_FAKE;
 633                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 634                 ret = offset;
 635         }
 636         else {
 637                 dquot->dq_off = offset;
 638                 fs = get_fs();
 639                 set_fs(KERNEL_DS);
 640                 if ((ret = filp->f_op->read(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset)) != sizeof(struct v2_disk_dqblk)) {
 641                         if (ret >= 0)
 642                                 ret = -EIO;
 643                         printk(KERN_ERR "VFS: Error while reading quota structure for id %u.\n", dquot->dq_id);
 644                         memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
 645                 }
 646                 else
 647                         ret = 0;
 648                 set_fs(fs);
 649                 disk2memdqb(&dquot->dq_dqb, &ddquot);
 650         }
 651         dqstats.reads++;
 652         return ret;
 653 }
 654
 655 /* Commit changes of dquot to disk - it might also mean deleting it when quota became fake one and user has no blocks... */
 656 static int v2_commit_dquot(struct dquot *dquot)
 657 {
 658         /* We clear the flag everytime so we don't loop when there was an IO error... */
 659         dquot->dq_flags &= ~DQ_MOD;
 660         if (dquot->dq_flags & DQ_FAKE && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 661                 return v2_delete_dquot(dquot);
 662         else
 663                 return v2_write_dquot(dquot);
 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_commit_dquot,
 673 };
 674
 675 static struct quota_format_type v2_quota_format = {
 676         qf_fmt_id:      QFMT_VFS_V0,
 677         qf_ops:         &v2_format_ops,
 678         qf_owner:       THIS_MODULE
 679 };
 680
 681 static int __init init_v2_quota_format(void)
 682 {
 683         return register_quota_format(&v2_quota_format);
 684 }
 685
 686 static void __exit exit_v2_quota_format(void)
 687 {
 688         unregister_quota_format(&v2_quota_format);
 689 }
 690
 691 EXPORT_NO_SYMBOLS;
 692
 693 module_init(init_v2_quota_format);
 694 module_exit(exit_v2_quota_format);