fs/quota.c

   1 /*
   2  * Quota code necessary even when VFS quota support is not compiled
   3  * into the kernel.  The interesting stuff is over in dquot.c, here
   4  * we have symbols for initial quotactl(2) handling, the sysctl(2)
   5  * variables, etc - things needed even when quota support disabled.
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/namei.h>
  10 #include <linux/slab.h>
  11 #include <asm/current.h>
  12 #include <asm/uaccess.h>
  13 #include <linux/compat.h>
  14 #include <linux/kernel.h>
  15 #include <linux/security.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/buffer_head.h>
  18 #include <linux/capability.h>
  19 #include <linux/quotaops.h>
  20 #include <linux/types.h>
  21
  22 /* Check validity of generic quotactl commands */
  23 static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
  24 {
  25         if (type >= MAXQUOTAS)
  26                 return -EINVAL;
  27         if (!sb && cmd != Q_SYNC)
  28                 return -ENODEV;
  29         /* Is operation supported? */
  30         if (sb && !sb->s_qcop)
  31                 return -ENOSYS;
  32
  33         switch (cmd) {
  34                 case Q_GETFMT:
  35                         break;
  36                 case Q_QUOTAON:
  37                         if (!sb->s_qcop->quota_on)
  38                                 return -ENOSYS;
  39                         break;
  40                 case Q_QUOTAOFF:
  41                         if (!sb->s_qcop->quota_off)
  42                                 return -ENOSYS;
  43                         break;
  44                 case Q_SETINFO:
  45                         if (!sb->s_qcop->set_info)
  46                                 return -ENOSYS;
  47                         break;
  48                 case Q_GETINFO:
  49                         if (!sb->s_qcop->get_info)
  50                                 return -ENOSYS;
  51                         break;
  52                 case Q_SETQUOTA:
  53                         if (!sb->s_qcop->set_dqblk)
  54                                 return -ENOSYS;
  55                         break;
  56                 case Q_GETQUOTA:
  57                         if (!sb->s_qcop->get_dqblk)
  58                                 return -ENOSYS;
  59                         break;
  60                 case Q_SYNC:
  61                         if (sb && !sb->s_qcop->quota_sync)
  62                                 return -ENOSYS;
  63                         break;
  64                 default:
  65                         return -EINVAL;
  66         }
  67
  68         /* Is quota turned on for commands which need it? */
  69         switch (cmd) {
  70                 case Q_GETFMT:
  71                 case Q_GETINFO:
  72                 case Q_QUOTAOFF:
  73                 case Q_SETINFO:
  74                 case Q_SETQUOTA:
  75                 case Q_GETQUOTA:
  76                         /* This is just informative test so we are satisfied without a lock */
  77                         if (!sb_has_quota_enabled(sb, type))
  78                                 return -ESRCH;
  79         }
  80
  81         /* Check privileges */
  82         if (cmd == Q_GETQUOTA) {
  83                 if (((type == USRQUOTA && current->euid != id) ||
  84                      (type == GRPQUOTA && !in_egroup_p(id))) &&
  85                     !capable(CAP_SYS_ADMIN))
  86                         return -EPERM;
  87         }
  88         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
  89                 if (!capable(CAP_SYS_ADMIN))
  90                         return -EPERM;
  91
  92         return 0;
  93 }
  94
  95 /* Check validity of XFS Quota Manager commands */
  96 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
  97 {
  98         if (type >= XQM_MAXQUOTAS)
  99                 return -EINVAL;
 100         if (!sb)
 101                 return -ENODEV;
 102         if (!sb->s_qcop)
 103                 return -ENOSYS;
 104
 105         switch (cmd) {
 106                 case Q_XQUOTAON:
 107                 case Q_XQUOTAOFF:
 108                 case Q_XQUOTARM:
 109                         if (!sb->s_qcop->set_xstate)
 110                                 return -ENOSYS;
 111                         break;
 112                 case Q_XGETQSTAT:
 113                         if (!sb->s_qcop->get_xstate)
 114                                 return -ENOSYS;
 115                         break;
 116                 case Q_XSETQLIM:
 117                         if (!sb->s_qcop->set_xquota)
 118                                 return -ENOSYS;
 119                         break;
 120                 case Q_XGETQUOTA:
 121                         if (!sb->s_qcop->get_xquota)
 122                                 return -ENOSYS;
 123                         break;
 124                 case Q_XQUOTASYNC:
 125                         if (!sb->s_qcop->quota_sync)
 126                                 return -ENOSYS;
 127                         break;
 128                 default:
 129                         return -EINVAL;
 130         }
 131
 132         /* Check privileges */
 133         if (cmd == Q_XGETQUOTA) {
 134                 if (((type == XQM_USRQUOTA && current->euid != id) ||
 135                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
 136                      !capable(CAP_SYS_ADMIN))
 137                         return -EPERM;
 138         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
 139                 if (!capable(CAP_SYS_ADMIN))
 140                         return -EPERM;
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
 147 {
 148         int error;
 149
 150         if (XQM_COMMAND(cmd))
 151                 error = xqm_quotactl_valid(sb, type, cmd, id);
 152         else
 153                 error = generic_quotactl_valid(sb, type, cmd, id);
 154         if (!error)
 155                 error = security_quotactl(cmd, type, id, sb);
 156         return error;
 157 }
 158
 159 static void quota_sync_sb(struct super_block *sb, int type)
 160 {
 161         int cnt;
 162
 163         sb->s_qcop->quota_sync(sb, type);
 164         /* This is not very clever (and fast) but currently I don't know about
 165          * any other simple way of getting quota data to disk and we must get
 166          * them there for userspace to be visible... */
 167         if (sb->s_op->sync_fs)
 168                 sb->s_op->sync_fs(sb, 1);
 169         sync_blockdev(sb->s_bdev);
 170
 171         /*
 172          * Now when everything is written we can discard the pagecache so
 173          * that userspace sees the changes.
 174          */
 175         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
 176         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 177                 if (type != -1 && cnt != type)
 178                         continue;
 179                 if (!sb_has_quota_enabled(sb, cnt))
 180                         continue;
 181                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
 182                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
 183                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
 184         }
 185         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 186 }
 187
 188 void sync_dquots(struct super_block *sb, int type)
 189 {
 190         int cnt, dirty;
 191
 192         if (sb) {
 193                 if (sb->s_qcop->quota_sync)
 194                         quota_sync_sb(sb, type);
 195                 return;
 196         }
 197
 198         spin_lock(&sb_lock);
 199 restart:
 200         list_for_each_entry(sb, &super_blocks, s_list) {
 201                 /* This test just improves performance so it needn't be reliable... */
 202                 for (cnt = 0, dirty = 0; cnt < MAXQUOTAS; cnt++)
 203                         if ((type == cnt || type == -1) && sb_has_quota_enabled(sb, cnt)
 204                             && info_any_dirty(&sb_dqopt(sb)->info[cnt]))
 205                                 dirty = 1;
 206                 if (!dirty)
 207                         continue;
 208                 sb->s_count++;
 209                 spin_unlock(&sb_lock);
 210                 down_read(&sb->s_umount);
 211                 if (sb->s_root && sb->s_qcop->quota_sync)
 212                         quota_sync_sb(sb, type);
 213                 up_read(&sb->s_umount);
 214                 spin_lock(&sb_lock);
 215                 if (__put_super_and_need_restart(sb))
 216                         goto restart;
 217         }
 218         spin_unlock(&sb_lock);
 219 }
 220
 221 /* Copy parameters and call proper function */
 222 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
 223 {
 224         int ret;
 225
 226         switch (cmd) {
 227                 case Q_QUOTAON: {
 228                         char *pathname;
 229
 230                         if (IS_ERR(pathname = getname(addr)))
 231                                 return PTR_ERR(pathname);
 232                         ret = sb->s_qcop->quota_on(sb, type, id, pathname);
 233                         putname(pathname);
 234                         return ret;
 235                 }
 236                 case Q_QUOTAOFF:
 237                         return sb->s_qcop->quota_off(sb, type);
 238
 239                 case Q_GETFMT: {
 240                         __u32 fmt;
 241
 242                         down_read(&sb_dqopt(sb)->dqptr_sem);
 243                         if (!sb_has_quota_enabled(sb, type)) {
 244                                 up_read(&sb_dqopt(sb)->dqptr_sem);
 245                                 return -ESRCH;
 246                         }
 247                         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
 248                         up_read(&sb_dqopt(sb)->dqptr_sem);
 249                         if (copy_to_user(addr, &fmt, sizeof(fmt)))
 250                                 return -EFAULT;
 251                         return 0;
 252                 }
 253                 case Q_GETINFO: {
 254                         struct if_dqinfo info;
 255
 256                         if ((ret = sb->s_qcop->get_info(sb, type, &info)))
 257                                 return ret;
 258                         if (copy_to_user(addr, &info, sizeof(info)))
 259                                 return -EFAULT;
 260                         return 0;
 261                 }
 262                 case Q_SETINFO: {
 263                         struct if_dqinfo info;
 264
 265                         if (copy_from_user(&info, addr, sizeof(info)))
 266                                 return -EFAULT;
 267                         return sb->s_qcop->set_info(sb, type, &info);
 268                 }
 269                 case Q_GETQUOTA: {
 270                         struct if_dqblk idq;
 271
 272                         if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
 273                                 return ret;
 274                         if (copy_to_user(addr, &idq, sizeof(idq)))
 275                                 return -EFAULT;
 276                         return 0;
 277                 }
 278                 case Q_SETQUOTA: {
 279                         struct if_dqblk idq;
 280
 281                         if (copy_from_user(&idq, addr, sizeof(idq)))
 282                                 return -EFAULT;
 283                         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 284                 }
 285                 case Q_SYNC:
 286                         sync_dquots(sb, type);
 287                         return 0;
 288
 289                 case Q_XQUOTAON:
 290                 case Q_XQUOTAOFF:
 291                 case Q_XQUOTARM: {
 292                         __u32 flags;
 293
 294                         if (copy_from_user(&flags, addr, sizeof(flags)))
 295                                 return -EFAULT;
 296                         return sb->s_qcop->set_xstate(sb, flags, cmd);
 297                 }
 298                 case Q_XGETQSTAT: {
 299                         struct fs_quota_stat fqs;
 300
 301                         if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
 302                                 return ret;
 303                         if (copy_to_user(addr, &fqs, sizeof(fqs)))
 304                                 return -EFAULT;
 305                         return 0;
 306                 }
 307                 case Q_XSETQLIM: {
 308                         struct fs_disk_quota fdq;
 309
 310                         if (copy_from_user(&fdq, addr, sizeof(fdq)))
 311                                 return -EFAULT;
 312                        return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 313                 }
 314                 case Q_XGETQUOTA: {
 315                         struct fs_disk_quota fdq;
 316
 317                         if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
 318                                 return ret;
 319                         if (copy_to_user(addr, &fdq, sizeof(fdq)))
 320                                 return -EFAULT;
 321                         return 0;
 322                 }
 323                 case Q_XQUOTASYNC:
 324                         return sb->s_qcop->quota_sync(sb, type);
 325                 /* We never reach here unless validity check is broken */
 326                 default:
 327                         BUG();
 328         }
 329         return 0;
 330 }
 331
 332 /*
 333  * look up a superblock on which quota ops will be performed
 334  * - use the name of a block device to find the superblock thereon
 335  */
 336 static inline struct super_block *quotactl_block(const char __user *special)
 337 {
 338 #ifdef CONFIG_BLOCK
 339         struct block_device *bdev;
 340         struct super_block *sb;
 341         char *tmp = getname(special);
 342
 343         if (IS_ERR(tmp))
 344                 return ERR_PTR(PTR_ERR(tmp));
 345         bdev = lookup_bdev(tmp);
 346         putname(tmp);
 347         if (IS_ERR(bdev))
 348                 return ERR_PTR(PTR_ERR(bdev));
 349         sb = get_super(bdev);
 350         bdput(bdev);
 351         if (!sb)
 352                 return ERR_PTR(-ENODEV);
 353
 354         return sb;
 355 #else
 356         return ERR_PTR(-ENODEV);
 357 #endif
 358 }
 359
 360 /*
 361  * This is the system call interface. This communicates with
 362  * the user-level programs. Currently this only supports diskquota
 363  * calls. Maybe we need to add the process quotas etc. in the future,
 364  * but we probably should use rlimits for that.
 365  */
 366 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
 367 {
 368         uint cmds, type;
 369         struct super_block *sb = NULL;
 370         int ret;
 371
 372         cmds = cmd >> SUBCMDSHIFT;
 373         type = cmd & SUBCMDMASK;
 374
 375         if (cmds != Q_SYNC || special) {
 376                 sb = quotactl_block(special);
 377                 if (IS_ERR(sb))
 378                         return PTR_ERR(sb);
 379         }
 380
 381         ret = check_quotactl_valid(sb, type, cmds, id);
 382         if (ret >= 0)
 383                 ret = do_quotactl(sb, type, cmds, id, addr);
 384         if (sb)
 385                 drop_super(sb);
 386
 387         return ret;
 388 }
 389
 390 #if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
 391 /*
 392  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
 393  * and is necessary due to alignment problems.
 394  */
 395 struct compat_if_dqblk {
 396         compat_u64 dqb_bhardlimit;
 397         compat_u64 dqb_bsoftlimit;
 398         compat_u64 dqb_curspace;
 399         compat_u64 dqb_ihardlimit;
 400         compat_u64 dqb_isoftlimit;
 401         compat_u64 dqb_curinodes;
 402         compat_u64 dqb_btime;
 403         compat_u64 dqb_itime;
 404         compat_uint_t dqb_valid;
 405 };
 406
 407 /* XFS structures */
 408 struct compat_fs_qfilestat {
 409         compat_u64 dqb_bhardlimit;
 410         compat_u64 qfs_nblks;
 411         compat_uint_t qfs_nextents;
 412 };
 413
 414 struct compat_fs_quota_stat {
 415         __s8            qs_version;
 416         __u16           qs_flags;
 417         __s8            qs_pad;
 418         struct compat_fs_qfilestat      qs_uquota;
 419         struct compat_fs_qfilestat      qs_gquota;
 420         compat_uint_t   qs_incoredqs;
 421         compat_int_t    qs_btimelimit;
 422         compat_int_t    qs_itimelimit;
 423         compat_int_t    qs_rtbtimelimit;
 424         __u16           qs_bwarnlimit;
 425         __u16           qs_iwarnlimit;
 426 };
 427
 428 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
 429                                                 qid_t id, void __user *addr)
 430 {
 431         unsigned int cmds;
 432         struct if_dqblk __user *dqblk;
 433         struct compat_if_dqblk __user *compat_dqblk;
 434         struct fs_quota_stat __user *fsqstat;
 435         struct compat_fs_quota_stat __user *compat_fsqstat;
 436         compat_uint_t data;
 437         u16 xdata;
 438         long ret;
 439
 440         cmds = cmd >> SUBCMDSHIFT;
 441
 442         switch (cmds) {
 443         case Q_GETQUOTA:
 444                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 445                 compat_dqblk = addr;
 446                 ret = sys_quotactl(cmd, special, id, dqblk);
 447                 if (ret)
 448                         break;
 449                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
 450                         get_user(data, &dqblk->dqb_valid) ||
 451                         put_user(data, &compat_dqblk->dqb_valid))
 452                         ret = -EFAULT;
 453                 break;
 454         case Q_SETQUOTA:
 455                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
 456                 compat_dqblk = addr;
 457                 ret = -EFAULT;
 458                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
 459                         get_user(data, &compat_dqblk->dqb_valid) ||
 460                         put_user(data, &dqblk->dqb_valid))
 461                         break;
 462                 ret = sys_quotactl(cmd, special, id, dqblk);
 463                 break;
 464         case Q_XGETQSTAT:
 465                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
 466                 compat_fsqstat = addr;
 467                 ret = sys_quotactl(cmd, special, id, fsqstat);
 468                 if (ret)
 469                         break;
 470                 ret = -EFAULT;
 471                 /* Copying qs_version, qs_flags, qs_pad */
 472                 if (copy_in_user(compat_fsqstat, fsqstat,
 473                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
 474                         break;
 475                 /* Copying qs_uquota */
 476                 if (copy_in_user(&compat_fsqstat->qs_uquota,
 477                         &fsqstat->qs_uquota,
 478                         sizeof(compat_fsqstat->qs_uquota)) ||
 479                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
 480                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
 481                         break;
 482                 /* Copying qs_gquota */
 483                 if (copy_in_user(&compat_fsqstat->qs_gquota,
 484                         &fsqstat->qs_gquota,
 485                         sizeof(compat_fsqstat->qs_gquota)) ||
 486                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
 487                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
 488                         break;
 489                 /* Copying the rest */
 490                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
 491                         &fsqstat->qs_incoredqs,
 492                         sizeof(struct compat_fs_quota_stat) -
 493                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
 494                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
 495                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
 496                         break;
 497                 ret = 0;
 498                 break;
 499         default:
 500                 ret = sys_quotactl(cmd, special, id, addr);
 501         }
 502         return ret;
 503 }
 504 #endif