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 #include <asm/uaccess.h>
  17
  18 MODULE_AUTHOR("Jan Kara");
  19 MODULE_DESCRIPTION("Quota format v2 support");
  20 MODULE_LICENSE("GPL");
  21
  22 #define __QUOTA_V2_PARANOIA
  23
  24 typedef char *dqbuf_t;
  25
  26 #define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
  27 #define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))
  28
  29 /* Check whether given file is really vfsv0 quotafile */
  30 static int v2_check_quota_file(struct super_block *sb, int type)
  31 {
  32         struct v2_disk_dqheader dqhead;
  33         struct file *f = sb_dqopt(sb)->files[type];
  34         mm_segment_t fs;
  35         ssize_t size;
  36         loff_t offset = 0;
  37         static const uint quota_magics[] = V2_INITQMAGICS;
  38         static const uint quota_versions[] = V2_INITQVERSIONS;
  39
  40         fs = get_fs();
  41         set_fs(KERNEL_DS);
  42         size = f->f_op->read(f, (char *)&dqhead, sizeof(struct v2_disk_dqheader), &offset);
  43         set_fs(fs);
  44         if (size != sizeof(struct v2_disk_dqheader))
  45                 return 0;
  46         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
  47             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
  48                 return 0;
  49         return 1;
  50 }
  51
  52 /* Read information header from quota file */
  53 static int v2_read_file_info(struct super_block *sb, int type)
  54 {
  55         mm_segment_t fs;
  56         struct v2_disk_dqinfo dinfo;
  57         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  58         struct file *f = sb_dqopt(sb)->files[type];
  59         ssize_t size;
  60         loff_t offset = V2_DQINFOOFF;
  61
  62         fs = get_fs();
  63         set_fs(KERNEL_DS);
  64         size = f->f_op->read(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
  65         set_fs(fs);
  66         if (size != sizeof(struct v2_disk_dqinfo)) {
  67                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
  68                         f->f_dentry->d_sb->s_id);
  69                 return -1;
  70         }
  71         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
  72         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
  73         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
  74         info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
  75         info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
  76         info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
  77         return 0;
  78 }
  79
  80 /* Write information header to quota file */
  81 static int v2_write_file_info(struct super_block *sb, int type)
  82 {
  83         mm_segment_t fs;
  84         struct v2_disk_dqinfo dinfo;
  85         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
  86         struct file *f = sb_dqopt(sb)->files[type];
  87         ssize_t size;
  88         loff_t offset = V2_DQINFOOFF;
  89
  90         spin_lock(&dq_data_lock);
  91         info->dqi_flags &= ~DQF_INFO_DIRTY;
  92         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
  93         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
  94         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
  95         spin_unlock(&dq_data_lock);
  96         dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
  97         dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
  98         dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
  99         fs = get_fs();
 100         set_fs(KERNEL_DS);
 101         size = f->f_op->write(f, (char *)&dinfo, sizeof(struct v2_disk_dqinfo), &offset);
 102         set_fs(fs);
 103         if (size != sizeof(struct v2_disk_dqinfo)) {
 104                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
 105                         f->f_dentry->d_sb->s_id);
 106                 return -1;
 107         }
 108         return 0;
 109 }
 110
 111 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
 112 {
 113         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
 114         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
 115         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
 116         m->dqb_itime = le64_to_cpu(d->dqb_itime);
 117         m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
 118         m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
 119         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
 120         m->dqb_btime = le64_to_cpu(d->dqb_btime);
 121 }
 122
 123 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
 124 {
 125         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
 126         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
 127         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
 128         d->dqb_itime = cpu_to_le64(m->dqb_itime);
 129         d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
 130         d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
 131         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
 132         d->dqb_btime = cpu_to_le64(m->dqb_btime);
 133         d->dqb_id = cpu_to_le32(id);
 134 }
 135
 136 static dqbuf_t getdqbuf(void)
 137 {
 138         dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_NOFS);
 139         if (!buf)
 140                 printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
 141         return buf;
 142 }
 143
 144 static inline void freedqbuf(dqbuf_t buf)
 145 {
 146         kfree(buf);
 147 }
 148
 149 static ssize_t read_blk(struct file *filp, uint blk, dqbuf_t buf)
 150 {
 151         mm_segment_t fs;
 152         ssize_t ret;
 153         loff_t offset = blk<<V2_DQBLKSIZE_BITS;
 154
 155         memset(buf, 0, V2_DQBLKSIZE);
 156         fs = get_fs();
 157         set_fs(KERNEL_DS);
 158         ret = filp->f_op->read(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 159         set_fs(fs);
 160         return ret;
 161 }
 162
 163 static ssize_t write_blk(struct file *filp, uint blk, dqbuf_t buf)
 164 {
 165         mm_segment_t fs;
 166         ssize_t ret;
 167         loff_t offset = blk<<V2_DQBLKSIZE_BITS;
 168
 169         fs = get_fs();
 170         set_fs(KERNEL_DS);
 171         ret = filp->f_op->write(filp, (char *)buf, V2_DQBLKSIZE, &offset);
 172         set_fs(fs);
 173         return ret;
 174
 175 }
 176
 177 /* Remove empty block from list and return it */
 178 static int get_free_dqblk(struct file *filp, int type)
 179 {
 180         dqbuf_t buf = getdqbuf();
 181         struct mem_dqinfo *info = sb_dqinfo(filp->f_dentry->d_sb, type);
 182         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 183         int ret, blk;
 184
 185         if (!buf)
 186                 return -ENOMEM;
 187         if (info->u.v2_i.dqi_free_blk) {
 188                 blk = info->u.v2_i.dqi_free_blk;
 189                 if ((ret = read_blk(filp, blk, buf)) < 0)
 190                         goto out_buf;
 191                 info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
 192         }
 193         else {
 194                 memset(buf, 0, V2_DQBLKSIZE);
 195                 if ((ret = write_blk(filp, info->u.v2_i.dqi_blocks, buf)) < 0)  /* Assure block allocation... */
 196                         goto out_buf;
 197                 blk = info->u.v2_i.dqi_blocks++;
 198         }
 199         mark_info_dirty(filp->f_dentry->d_sb, type);
 200         ret = blk;
 201 out_buf:
 202         freedqbuf(buf);
 203         return ret;
 204 }
 205
 206 /* Insert empty block to the list */
 207 static int put_free_dqblk(struct file *filp, int type, dqbuf_t buf, uint blk)
 208 {
 209         struct mem_dqinfo *info = sb_dqinfo(filp->f_dentry->d_sb, type);
 210         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 211         int err;
 212
 213         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
 214         dh->dqdh_prev_free = cpu_to_le32(0);
 215         dh->dqdh_entries = cpu_to_le16(0);
 216         info->u.v2_i.dqi_free_blk = blk;
 217         mark_info_dirty(filp->f_dentry->d_sb, type);
 218         if ((err = write_blk(filp, blk, buf)) < 0)      /* Some strange block. We had better leave it... */
 219                 return err;
 220         return 0;
 221 }
 222
 223 /* Remove given block from the list of blocks with free entries */
 224 static int remove_free_dqentry(struct file *filp, int type, dqbuf_t buf, uint blk)
 225 {
 226         dqbuf_t tmpbuf = getdqbuf();
 227         struct mem_dqinfo *info = sb_dqinfo(filp->f_dentry->d_sb, type);
 228         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 229         uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
 230         int err;
 231
 232         if (!tmpbuf)
 233                 return -ENOMEM;
 234         if (nextblk) {
 235                 if ((err = read_blk(filp, nextblk, tmpbuf)) < 0)
 236                         goto out_buf;
 237                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
 238                 if ((err = write_blk(filp, nextblk, tmpbuf)) < 0)
 239                         goto out_buf;
 240         }
 241         if (prevblk) {
 242                 if ((err = read_blk(filp, prevblk, tmpbuf)) < 0)
 243                         goto out_buf;
 244                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
 245                 if ((err = write_blk(filp, prevblk, tmpbuf)) < 0)
 246                         goto out_buf;
 247         }
 248         else {
 249                 info->u.v2_i.dqi_free_entry = nextblk;
 250                 mark_info_dirty(filp->f_dentry->d_sb, type);
 251         }
 252         freedqbuf(tmpbuf);
 253         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
 254         if (write_blk(filp, blk, buf) < 0)      /* No matter whether write succeeds block is out of list */
 255                 printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
 256         return 0;
 257 out_buf:
 258         freedqbuf(tmpbuf);
 259         return err;
 260 }
 261
 262 /* Insert given block to the beginning of list with free entries */
 263 static int insert_free_dqentry(struct file *filp, int type, dqbuf_t buf, uint blk)
 264 {
 265         dqbuf_t tmpbuf = getdqbuf();
 266         struct mem_dqinfo *info = sb_dqinfo(filp->f_dentry->d_sb, type);
 267         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
 268         int err;
 269
 270         if (!tmpbuf)
 271                 return -ENOMEM;
 272         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
 273         dh->dqdh_prev_free = cpu_to_le32(0);
 274         if ((err = write_blk(filp, blk, buf)) < 0)
 275                 goto out_buf;
 276         if (info->u.v2_i.dqi_free_entry) {
 277                 if ((err = read_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 278                         goto out_buf;
 279                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
 280                 if ((err = write_blk(filp, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
 281                         goto out_buf;
 282         }
 283         freedqbuf(tmpbuf);
 284         info->u.v2_i.dqi_free_entry = blk;
 285         mark_info_dirty(filp->f_dentry->d_sb, type);
 286         return 0;
 287 out_buf:
 288         freedqbuf(tmpbuf);
 289         return err;
 290 }
 291
 292 /* Find space for dquot */
 293 static uint find_free_dqentry(struct dquot *dquot, int *err)
 294 {
 295         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 296         struct mem_dqinfo *info = sb_dqopt(dquot->dq_sb)->info+dquot->dq_type;
 297         uint blk, i;
 298         struct v2_disk_dqdbheader *dh;
 299         struct v2_disk_dqblk *ddquot;
 300         struct v2_disk_dqblk fakedquot;
 301         dqbuf_t buf;
 302
 303         *err = 0;
 304         if (!(buf = getdqbuf())) {
 305                 *err = -ENOMEM;
 306                 return 0;
 307         }
 308         dh = (struct v2_disk_dqdbheader *)buf;
 309         ddquot = GETENTRIES(buf);
 310         if (info->u.v2_i.dqi_free_entry) {
 311                 blk = info->u.v2_i.dqi_free_entry;
 312                 if ((*err = read_blk(filp, blk, buf)) < 0)
 313                         goto out_buf;
 314         }
 315         else {
 316                 blk = get_free_dqblk(filp, dquot->dq_type);
 317                 if ((int)blk < 0) {
 318                         *err = blk;
 319                         freedqbuf(buf);
 320                         return 0;
 321                 }
 322                 memset(buf, 0, V2_DQBLKSIZE);
 323                 info->u.v2_i.dqi_free_entry = blk;      /* This is enough as block is already zeroed and entry list is empty... */
 324                 mark_info_dirty(dquot->dq_sb, dquot->dq_type);
 325         }
 326         if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
 327                 if ((*err = remove_free_dqentry(filp, dquot->dq_type, buf, blk)) < 0) {
 328                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
 329                         goto out_buf;
 330                 }
 331         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
 332         memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 333         /* Find free structure in block */
 334         for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
 335 #ifdef __QUOTA_V2_PARANOIA
 336         if (i == V2_DQSTRINBLK) {
 337                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
 338                 *err = -EIO;
 339                 goto out_buf;
 340         }
 341 #endif
 342         if ((*err = write_blk(filp, blk, buf)) < 0) {
 343                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
 344                 goto out_buf;
 345         }
 346         dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
 347         freedqbuf(buf);
 348         return blk;
 349 out_buf:
 350         freedqbuf(buf);
 351         return 0;
 352 }
 353
 354 /* Insert reference to structure into the trie */
 355 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
 356 {
 357         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 358         dqbuf_t buf;
 359         int ret = 0, newson = 0, newact = 0;
 360         u32 *ref;
 361         uint newblk;
 362
 363         if (!(buf = getdqbuf()))
 364                 return -ENOMEM;
 365         if (!*treeblk) {
 366                 ret = get_free_dqblk(filp, dquot->dq_type);
 367                 if (ret < 0)
 368                         goto out_buf;
 369                 *treeblk = ret;
 370                 memset(buf, 0, V2_DQBLKSIZE);
 371                 newact = 1;
 372         }
 373         else {
 374                 if ((ret = read_blk(filp, *treeblk, buf)) < 0) {
 375                         printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
 376                         goto out_buf;
 377                 }
 378         }
 379         ref = (u32 *)buf;
 380         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 381         if (!newblk)
 382                 newson = 1;
 383         if (depth == V2_DQTREEDEPTH-1) {
 384 #ifdef __QUOTA_V2_PARANOIA
 385                 if (newblk) {
 386                         printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", ref[GETIDINDEX(dquot->dq_id, depth)]);
 387                         ret = -EIO;
 388                         goto out_buf;
 389                 }
 390 #endif
 391                 newblk = find_free_dqentry(dquot, &ret);
 392         }
 393         else
 394                 ret = do_insert_tree(dquot, &newblk, depth+1);
 395         if (newson && ret >= 0) {
 396                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
 397                 ret = write_blk(filp, *treeblk, buf);
 398         }
 399         else if (newact && ret < 0)
 400                 put_free_dqblk(filp, dquot->dq_type, buf, *treeblk);
 401 out_buf:
 402         freedqbuf(buf);
 403         return ret;
 404 }
 405
 406 /* Wrapper for inserting quota structure into tree */
 407 static inline int dq_insert_tree(struct dquot *dquot)
 408 {
 409         int tmp = V2_DQTREEOFF;
 410         return do_insert_tree(dquot, &tmp, 0);
 411 }
 412
 413 /*
 414  *      We don't have to be afraid of deadlocks as we never have quotas on quota files...
 415  */
 416 static int v2_write_dquot(struct dquot *dquot)
 417 {
 418         int type = dquot->dq_type;
 419         struct file *filp;
 420         mm_segment_t fs;
 421         loff_t offset;
 422         ssize_t ret;
 423         struct v2_disk_dqblk ddquot, empty;
 424
 425         /* dq_off is guarded by dqio_sem */
 426         if (!dquot->dq_off)
 427                 if ((ret = dq_insert_tree(dquot)) < 0) {
 428                         printk(KERN_ERR "VFS: Error %Zd occurred while creating quota.\n", ret);
 429                         return ret;
 430                 }
 431         filp = sb_dqopt(dquot->dq_sb)->files[type];
 432         offset = dquot->dq_off;
 433         spin_lock(&dq_data_lock);
 434         mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
 435         /* Argh... We may need to write structure full of zeroes but that would be
 436          * treated as an empty place by the rest of the code. Format change would
 437          * be definitely cleaner but the problems probably are not worth it */
 438         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 439         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 440                 ddquot.dqb_itime = cpu_to_le64(1);
 441         spin_unlock(&dq_data_lock);
 442         fs = get_fs();
 443         set_fs(KERNEL_DS);
 444         ret = filp->f_op->write(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset);
 445         set_fs(fs);
 446         if (ret != sizeof(struct v2_disk_dqblk)) {
 447                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
 448                 if (ret >= 0)
 449                         ret = -ENOSPC;
 450         }
 451         else
 452                 ret = 0;
 453         dqstats.writes++;
 454
 455         return ret;
 456 }
 457
 458 /* Free dquot entry in data block */
 459 static int free_dqentry(struct dquot *dquot, uint blk)
 460 {
 461         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 462         struct v2_disk_dqdbheader *dh;
 463         dqbuf_t buf = getdqbuf();
 464         int ret = 0;
 465
 466         if (!buf)
 467                 return -ENOMEM;
 468         if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
 469                 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));
 470                 goto out_buf;
 471         }
 472         if ((ret = read_blk(filp, blk, buf)) < 0) {
 473                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
 474                 goto out_buf;
 475         }
 476         dh = (struct v2_disk_dqdbheader *)buf;
 477         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
 478         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
 479                 if ((ret = remove_free_dqentry(filp, dquot->dq_type, buf, blk)) < 0 ||
 480                     (ret = put_free_dqblk(filp, dquot->dq_type, buf, blk)) < 0) {
 481                         printk(KERN_ERR "VFS: Can't move quota data block (%u) to free list.\n", blk);
 482                         goto out_buf;
 483                 }
 484         }
 485         else {
 486                 memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0, sizeof(struct v2_disk_dqblk));
 487                 if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
 488                         /* Insert will write block itself */
 489                         if ((ret = insert_free_dqentry(filp, dquot->dq_type, buf, blk)) < 0) {
 490                                 printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
 491                                 goto out_buf;
 492                         }
 493                 }
 494                 else
 495                         if ((ret = write_blk(filp, blk, buf)) < 0) {
 496                                 printk(KERN_ERR "VFS: Can't write quota data block %u\n", blk);
 497                                 goto out_buf;
 498                         }
 499         }
 500         dquot->dq_off = 0;      /* Quota is now unattached */
 501 out_buf:
 502         freedqbuf(buf);
 503         return ret;
 504 }
 505
 506 /* Remove reference to dquot from tree */
 507 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
 508 {
 509         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 510         dqbuf_t buf = getdqbuf();
 511         int ret = 0;
 512         uint newblk;
 513         u32 *ref = (u32 *)buf;
 514
 515         if (!buf)
 516                 return -ENOMEM;
 517         if ((ret = read_blk(filp, *blk, buf)) < 0) {
 518                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
 519                 goto out_buf;
 520         }
 521         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 522         if (depth == V2_DQTREEDEPTH-1) {
 523                 ret = free_dqentry(dquot, newblk);
 524                 newblk = 0;
 525         }
 526         else
 527                 ret = remove_tree(dquot, &newblk, depth+1);
 528         if (ret >= 0 && !newblk) {
 529                 int i;
 530                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
 531                 for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
 532                 if (i == V2_DQBLKSIZE) {
 533                         put_free_dqblk(filp, dquot->dq_type, buf, *blk);
 534                         *blk = 0;
 535                 }
 536                 else
 537                         if ((ret = write_blk(filp, *blk, buf)) < 0)
 538                                 printk(KERN_ERR "VFS: Can't write quota tree block %u.\n", *blk);
 539         }
 540 out_buf:
 541         freedqbuf(buf);
 542         return ret;
 543 }
 544
 545 /* Delete dquot from tree */
 546 static int v2_delete_dquot(struct dquot *dquot)
 547 {
 548         uint tmp = V2_DQTREEOFF;
 549
 550         if (!dquot->dq_off)     /* Even not allocated? */
 551                 return 0;
 552         return remove_tree(dquot, &tmp, 0);
 553 }
 554
 555 /* Find entry in block */
 556 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
 557 {
 558         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 559         dqbuf_t buf = getdqbuf();
 560         loff_t ret = 0;
 561         int i;
 562         struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
 563
 564         if (!buf)
 565                 return -ENOMEM;
 566         if ((ret = read_blk(filp, blk, buf)) < 0) {
 567                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 568                 goto out_buf;
 569         }
 570         if (dquot->dq_id)
 571                 for (i = 0; i < V2_DQSTRINBLK && le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
 572         else {  /* ID 0 as a bit more complicated searching... */
 573                 struct v2_disk_dqblk fakedquot;
 574
 575                 memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
 576                 for (i = 0; i < V2_DQSTRINBLK; i++)
 577                         if (!le32_to_cpu(ddquot[i].dqb_id) && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
 578                                 break;
 579         }
 580         if (i == V2_DQSTRINBLK) {
 581                 printk(KERN_ERR "VFS: Quota for id %u referenced but not present.\n", dquot->dq_id);
 582                 ret = -EIO;
 583                 goto out_buf;
 584         }
 585         else
 586                 ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
 587 out_buf:
 588         freedqbuf(buf);
 589         return ret;
 590 }
 591
 592 /* Find entry for given id in the tree */
 593 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
 594 {
 595         struct file *filp = sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
 596         dqbuf_t buf = getdqbuf();
 597         loff_t ret = 0;
 598         u32 *ref = (u32 *)buf;
 599
 600         if (!buf)
 601                 return -ENOMEM;
 602         if ((ret = read_blk(filp, blk, buf)) < 0) {
 603                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
 604                 goto out_buf;
 605         }
 606         ret = 0;
 607         blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
 608         if (!blk)       /* No reference? */
 609                 goto out_buf;
 610         if (depth < V2_DQTREEDEPTH-1)
 611                 ret = find_tree_dqentry(dquot, blk, depth+1);
 612         else
 613                 ret = find_block_dqentry(dquot, blk);
 614 out_buf:
 615         freedqbuf(buf);
 616         return ret;
 617 }
 618
 619 /* Find entry for given id in the tree - wrapper function */
 620 static inline loff_t find_dqentry(struct dquot *dquot)
 621 {
 622         return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
 623 }
 624
 625 static int v2_read_dquot(struct dquot *dquot)
 626 {
 627         int type = dquot->dq_type;
 628         struct file *filp;
 629         mm_segment_t fs;
 630         loff_t offset;
 631         struct v2_disk_dqblk ddquot, empty;
 632         int ret = 0;
 633
 634         filp = sb_dqopt(dquot->dq_sb)->files[type];
 635
 636 #ifdef __QUOTA_V2_PARANOIA
 637         if (!filp || !dquot->dq_sb) {   /* Invalidated quota? */
 638                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
 639                 return -EIO;
 640         }
 641 #endif
 642         offset = find_dqentry(dquot);
 643         if (offset <= 0) {      /* Entry not present? */
 644                 if (offset < 0)
 645                         printk(KERN_ERR "VFS: Can't read quota structure for id %u.\n", dquot->dq_id);
 646                 dquot->dq_off = 0;
 647                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
 648                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
 649                 ret = offset;
 650         }
 651         else {
 652                 dquot->dq_off = offset;
 653                 fs = get_fs();
 654                 set_fs(KERNEL_DS);
 655                 if ((ret = filp->f_op->read(filp, (char *)&ddquot, sizeof(struct v2_disk_dqblk), &offset)) != sizeof(struct v2_disk_dqblk)) {
 656                         if (ret >= 0)
 657                                 ret = -EIO;
 658                         printk(KERN_ERR "VFS: Error while reading quota structure for id %u.\n", dquot->dq_id);
 659                         memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
 660                 }
 661                 else {
 662                         ret = 0;
 663                         /* We need to escape back all-zero structure */
 664                         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
 665                         empty.dqb_itime = cpu_to_le64(1);
 666                         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
 667                                 ddquot.dqb_itime = 0;
 668                 }
 669                 set_fs(fs);
 670                 disk2memdqb(&dquot->dq_dqb, &ddquot);
 671                 if (!dquot->dq_dqb.dqb_bhardlimit &&
 672                         !dquot->dq_dqb.dqb_bsoftlimit &&
 673                         !dquot->dq_dqb.dqb_ihardlimit &&
 674                         !dquot->dq_dqb.dqb_isoftlimit)
 675                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
 676         }
 677         dqstats.reads++;
 678
 679         return ret;
 680 }
 681
 682 /* Check whether dquot should not be deleted. We know we are
 683  * the only one operating on dquot (thanks to dq_lock) */
 684 static int v2_release_dquot(struct dquot *dquot)
 685 {
 686         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
 687                 return v2_delete_dquot(dquot);
 688         return 0;
 689 }
 690
 691 static struct quota_format_ops v2_format_ops = {
 692         .check_quota_file       = v2_check_quota_file,
 693         .read_file_info         = v2_read_file_info,
 694         .write_file_info        = v2_write_file_info,
 695         .free_file_info         = NULL,
 696         .read_dqblk             = v2_read_dquot,
 697         .commit_dqblk           = v2_write_dquot,
 698         .release_dqblk          = v2_release_dquot,
 699 };
 700
 701 static struct quota_format_type v2_quota_format = {
 702         .qf_fmt_id      = QFMT_VFS_V0,
 703         .qf_ops         = &v2_format_ops,
 704         .qf_owner       = THIS_MODULE
 705 };
 706
 707 static int __init init_v2_quota_format(void)
 708 {
 709         return register_quota_format(&v2_quota_format);
 710 }
 711
 712 static void __exit exit_v2_quota_format(void)
 713 {
 714         unregister_quota_format(&v2_quota_format);
 715 }
 716
 717 module_init(init_v2_quota_format);
 718 module_exit(exit_v2_quota_format);