quota: cleanup dquota sync functions (version 4)
[linux-2.6.git] / fs / quota / 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,
24                                   qid_t id)
25 {
26         if (type >= MAXQUOTAS)
27                 return -EINVAL;
28         if (!sb && cmd != Q_SYNC)
29                 return -ENODEV;
30         /* Is operation supported? */
31         if (sb && !sb->s_qcop)
32                 return -ENOSYS;
33
34         switch (cmd) {
35                 case Q_GETFMT:
36                         break;
37                 case Q_QUOTAON:
38                         if (!sb->s_qcop->quota_on)
39                                 return -ENOSYS;
40                         break;
41                 case Q_QUOTAOFF:
42                         if (!sb->s_qcop->quota_off)
43                                 return -ENOSYS;
44                         break;
45                 case Q_SETINFO:
46                         if (!sb->s_qcop->set_info)
47                                 return -ENOSYS;
48                         break;
49                 case Q_GETINFO:
50                         if (!sb->s_qcop->get_info)
51                                 return -ENOSYS;
52                         break;
53                 case Q_SETQUOTA:
54                         if (!sb->s_qcop->set_dqblk)
55                                 return -ENOSYS;
56                         break;
57                 case Q_GETQUOTA:
58                         if (!sb->s_qcop->get_dqblk)
59                                 return -ENOSYS;
60                         break;
61                 case Q_SYNC:
62                         if (sb && !sb->s_qcop->quota_sync)
63                                 return -ENOSYS;
64                         break;
65                 default:
66                         return -EINVAL;
67         }
68
69         /* Is quota turned on for commands which need it? */
70         switch (cmd) {
71                 case Q_GETFMT:
72                 case Q_GETINFO:
73                 case Q_SETINFO:
74                 case Q_SETQUOTA:
75                 case Q_GETQUOTA:
76                         /* This is just an informative test so we are satisfied
77                          * without the lock */
78                         if (!sb_has_quota_active(sb, type))
79                                 return -ESRCH;
80         }
81
82         /* Check privileges */
83         if (cmd == Q_GETQUOTA) {
84                 if (((type == USRQUOTA && current_euid() != id) ||
85                      (type == GRPQUOTA && !in_egroup_p(id))) &&
86                     !capable(CAP_SYS_ADMIN))
87                         return -EPERM;
88         }
89         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
90                 if (!capable(CAP_SYS_ADMIN))
91                         return -EPERM;
92
93         return 0;
94 }
95
96 /* Check validity of XFS Quota Manager commands */
97 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
98                               qid_t id)
99 {
100         if (type >= XQM_MAXQUOTAS)
101                 return -EINVAL;
102         if (!sb)
103                 return -ENODEV;
104         if (!sb->s_qcop)
105                 return -ENOSYS;
106
107         switch (cmd) {
108                 case Q_XQUOTAON:
109                 case Q_XQUOTAOFF:
110                 case Q_XQUOTARM:
111                         if (!sb->s_qcop->set_xstate)
112                                 return -ENOSYS;
113                         break;
114                 case Q_XGETQSTAT:
115                         if (!sb->s_qcop->get_xstate)
116                                 return -ENOSYS;
117                         break;
118                 case Q_XSETQLIM:
119                         if (!sb->s_qcop->set_xquota)
120                                 return -ENOSYS;
121                         break;
122                 case Q_XGETQUOTA:
123                         if (!sb->s_qcop->get_xquota)
124                                 return -ENOSYS;
125                         break;
126                 case Q_XQUOTASYNC:
127                         if (!sb->s_qcop->quota_sync)
128                                 return -ENOSYS;
129                         break;
130                 default:
131                         return -EINVAL;
132         }
133
134         /* Check privileges */
135         if (cmd == Q_XGETQUOTA) {
136                 if (((type == XQM_USRQUOTA && current_euid() != id) ||
137                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
138                      !capable(CAP_SYS_ADMIN))
139                         return -EPERM;
140         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
141                 if (!capable(CAP_SYS_ADMIN))
142                         return -EPERM;
143         }
144
145         return 0;
146 }
147
148 static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
149                                 qid_t id)
150 {
151         int error;
152
153         if (XQM_COMMAND(cmd))
154                 error = xqm_quotactl_valid(sb, type, cmd, id);
155         else
156                 error = generic_quotactl_valid(sb, type, cmd, id);
157         if (!error)
158                 error = security_quotactl(cmd, type, id, sb);
159         return error;
160 }
161
162 #ifdef CONFIG_QUOTA
163 void sync_quota_sb(struct super_block *sb, int type)
164 {
165         int cnt;
166
167         if (!sb->s_qcop->quota_sync)
168                 return;
169
170         sb->s_qcop->quota_sync(sb, type);
171
172         if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
173                 return;
174         /* This is not very clever (and fast) but currently I don't know about
175          * any other simple way of getting quota data to disk and we must get
176          * them there for userspace to be visible... */
177         if (sb->s_op->sync_fs)
178                 sb->s_op->sync_fs(sb, 1);
179         sync_blockdev(sb->s_bdev);
180
181         /*
182          * Now when everything is written we can discard the pagecache so
183          * that userspace sees the changes.
184          */
185         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
186         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
187                 if (type != -1 && cnt != type)
188                         continue;
189                 if (!sb_has_quota_active(sb, cnt))
190                         continue;
191                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
192                                   I_MUTEX_QUOTA);
193                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
194                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
195         }
196         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
197 }
198 #endif
199
200 static void sync_dquots(int type)
201 {
202         struct super_block *sb;
203         int cnt;
204
205         spin_lock(&sb_lock);
206 restart:
207         list_for_each_entry(sb, &super_blocks, s_list) {
208                 /* This test just improves performance so it needn't be
209                  * reliable... */
210                 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
211                         if (type != -1 && type != cnt)
212                                 continue;
213                         if (!sb_has_quota_active(sb, cnt))
214                                 continue;
215                         if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
216                            list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
217                                 continue;
218                         break;
219                 }
220                 if (cnt == MAXQUOTAS)
221                         continue;
222                 sb->s_count++;
223                 spin_unlock(&sb_lock);
224                 down_read(&sb->s_umount);
225                 if (sb->s_root)
226                         sync_quota_sb(sb, type);
227                 up_read(&sb->s_umount);
228                 spin_lock(&sb_lock);
229                 if (__put_super_and_need_restart(sb))
230                         goto restart;
231         }
232         spin_unlock(&sb_lock);
233 }
234
235 /* Copy parameters and call proper function */
236 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
237                        void __user *addr)
238 {
239         int ret;
240
241         switch (cmd) {
242                 case Q_QUOTAON: {
243                         char *pathname;
244
245                         pathname = getname(addr);
246                         if (IS_ERR(pathname))
247                                 return PTR_ERR(pathname);
248                         ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
249                         putname(pathname);
250                         return ret;
251                 }
252                 case Q_QUOTAOFF:
253                         return sb->s_qcop->quota_off(sb, type, 0);
254
255                 case Q_GETFMT: {
256                         __u32 fmt;
257
258                         down_read(&sb_dqopt(sb)->dqptr_sem);
259                         if (!sb_has_quota_active(sb, type)) {
260                                 up_read(&sb_dqopt(sb)->dqptr_sem);
261                                 return -ESRCH;
262                         }
263                         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
264                         up_read(&sb_dqopt(sb)->dqptr_sem);
265                         if (copy_to_user(addr, &fmt, sizeof(fmt)))
266                                 return -EFAULT;
267                         return 0;
268                 }
269                 case Q_GETINFO: {
270                         struct if_dqinfo info;
271
272                         ret = sb->s_qcop->get_info(sb, type, &info);
273                         if (ret)
274                                 return ret;
275                         if (copy_to_user(addr, &info, sizeof(info)))
276                                 return -EFAULT;
277                         return 0;
278                 }
279                 case Q_SETINFO: {
280                         struct if_dqinfo info;
281
282                         if (copy_from_user(&info, addr, sizeof(info)))
283                                 return -EFAULT;
284                         return sb->s_qcop->set_info(sb, type, &info);
285                 }
286                 case Q_GETQUOTA: {
287                         struct if_dqblk idq;
288
289                         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
290                         if (ret)
291                                 return ret;
292                         if (copy_to_user(addr, &idq, sizeof(idq)))
293                                 return -EFAULT;
294                         return 0;
295                 }
296                 case Q_SETQUOTA: {
297                         struct if_dqblk idq;
298
299                         if (copy_from_user(&idq, addr, sizeof(idq)))
300                                 return -EFAULT;
301                         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
302                 }
303                 case Q_SYNC:
304                         if (sb)
305                                 sync_quota_sb(sb, type);
306                         else
307                                 sync_dquots(type);
308                         return 0;
309
310                 case Q_XQUOTAON:
311                 case Q_XQUOTAOFF:
312                 case Q_XQUOTARM: {
313                         __u32 flags;
314
315                         if (copy_from_user(&flags, addr, sizeof(flags)))
316                                 return -EFAULT;
317                         return sb->s_qcop->set_xstate(sb, flags, cmd);
318                 }
319                 case Q_XGETQSTAT: {
320                         struct fs_quota_stat fqs;
321                 
322                         if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
323                                 return ret;
324                         if (copy_to_user(addr, &fqs, sizeof(fqs)))
325                                 return -EFAULT;
326                         return 0;
327                 }
328                 case Q_XSETQLIM: {
329                         struct fs_disk_quota fdq;
330
331                         if (copy_from_user(&fdq, addr, sizeof(fdq)))
332                                 return -EFAULT;
333                        return sb->s_qcop->set_xquota(sb, type, id, &fdq);
334                 }
335                 case Q_XGETQUOTA: {
336                         struct fs_disk_quota fdq;
337
338                         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
339                         if (ret)
340                                 return ret;
341                         if (copy_to_user(addr, &fdq, sizeof(fdq)))
342                                 return -EFAULT;
343                         return 0;
344                 }
345                 case Q_XQUOTASYNC:
346                         return sb->s_qcop->quota_sync(sb, type);
347                 /* We never reach here unless validity check is broken */
348                 default:
349                         BUG();
350         }
351         return 0;
352 }
353
354 /*
355  * look up a superblock on which quota ops will be performed
356  * - use the name of a block device to find the superblock thereon
357  */
358 static struct super_block *quotactl_block(const char __user *special)
359 {
360 #ifdef CONFIG_BLOCK
361         struct block_device *bdev;
362         struct super_block *sb;
363         char *tmp = getname(special);
364
365         if (IS_ERR(tmp))
366                 return ERR_CAST(tmp);
367         bdev = lookup_bdev(tmp);
368         putname(tmp);
369         if (IS_ERR(bdev))
370                 return ERR_CAST(bdev);
371         sb = get_super(bdev);
372         bdput(bdev);
373         if (!sb)
374                 return ERR_PTR(-ENODEV);
375
376         return sb;
377 #else
378         return ERR_PTR(-ENODEV);
379 #endif
380 }
381
382 /*
383  * This is the system call interface. This communicates with
384  * the user-level programs. Currently this only supports diskquota
385  * calls. Maybe we need to add the process quotas etc. in the future,
386  * but we probably should use rlimits for that.
387  */
388 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
389                 qid_t, id, void __user *, addr)
390 {
391         uint cmds, type;
392         struct super_block *sb = NULL;
393         int ret;
394
395         cmds = cmd >> SUBCMDSHIFT;
396         type = cmd & SUBCMDMASK;
397
398         if (cmds != Q_SYNC || special) {
399                 sb = quotactl_block(special);
400                 if (IS_ERR(sb))
401                         return PTR_ERR(sb);
402         }
403
404         ret = check_quotactl_valid(sb, type, cmds, id);
405         if (ret >= 0)
406                 ret = do_quotactl(sb, type, cmds, id, addr);
407         if (sb)
408                 drop_super(sb);
409
410         return ret;
411 }
412
413 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
414 /*
415  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
416  * and is necessary due to alignment problems.
417  */
418 struct compat_if_dqblk {
419         compat_u64 dqb_bhardlimit;
420         compat_u64 dqb_bsoftlimit;
421         compat_u64 dqb_curspace;
422         compat_u64 dqb_ihardlimit;
423         compat_u64 dqb_isoftlimit;
424         compat_u64 dqb_curinodes;
425         compat_u64 dqb_btime;
426         compat_u64 dqb_itime;
427         compat_uint_t dqb_valid;
428 };
429
430 /* XFS structures */
431 struct compat_fs_qfilestat {
432         compat_u64 dqb_bhardlimit;
433         compat_u64 qfs_nblks;
434         compat_uint_t qfs_nextents;
435 };
436
437 struct compat_fs_quota_stat {
438         __s8            qs_version;
439         __u16           qs_flags;
440         __s8            qs_pad;
441         struct compat_fs_qfilestat      qs_uquota;
442         struct compat_fs_qfilestat      qs_gquota;
443         compat_uint_t   qs_incoredqs;
444         compat_int_t    qs_btimelimit;
445         compat_int_t    qs_itimelimit;
446         compat_int_t    qs_rtbtimelimit;
447         __u16           qs_bwarnlimit;
448         __u16           qs_iwarnlimit;
449 };
450
451 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
452                                                 qid_t id, void __user *addr)
453 {
454         unsigned int cmds;
455         struct if_dqblk __user *dqblk;
456         struct compat_if_dqblk __user *compat_dqblk;
457         struct fs_quota_stat __user *fsqstat;
458         struct compat_fs_quota_stat __user *compat_fsqstat;
459         compat_uint_t data;
460         u16 xdata;
461         long ret;
462
463         cmds = cmd >> SUBCMDSHIFT;
464
465         switch (cmds) {
466         case Q_GETQUOTA:
467                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
468                 compat_dqblk = addr;
469                 ret = sys_quotactl(cmd, special, id, dqblk);
470                 if (ret)
471                         break;
472                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
473                         get_user(data, &dqblk->dqb_valid) ||
474                         put_user(data, &compat_dqblk->dqb_valid))
475                         ret = -EFAULT;
476                 break;
477         case Q_SETQUOTA:
478                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
479                 compat_dqblk = addr;
480                 ret = -EFAULT;
481                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
482                         get_user(data, &compat_dqblk->dqb_valid) ||
483                         put_user(data, &dqblk->dqb_valid))
484                         break;
485                 ret = sys_quotactl(cmd, special, id, dqblk);
486                 break;
487         case Q_XGETQSTAT:
488                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
489                 compat_fsqstat = addr;
490                 ret = sys_quotactl(cmd, special, id, fsqstat);
491                 if (ret)
492                         break;
493                 ret = -EFAULT;
494                 /* Copying qs_version, qs_flags, qs_pad */
495                 if (copy_in_user(compat_fsqstat, fsqstat,
496                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
497                         break;
498                 /* Copying qs_uquota */
499                 if (copy_in_user(&compat_fsqstat->qs_uquota,
500                         &fsqstat->qs_uquota,
501                         sizeof(compat_fsqstat->qs_uquota)) ||
502                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
503                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
504                         break;
505                 /* Copying qs_gquota */
506                 if (copy_in_user(&compat_fsqstat->qs_gquota,
507                         &fsqstat->qs_gquota,
508                         sizeof(compat_fsqstat->qs_gquota)) ||
509                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
510                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
511                         break;
512                 /* Copying the rest */
513                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
514                         &fsqstat->qs_incoredqs,
515                         sizeof(struct compat_fs_quota_stat) -
516                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
517                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
518                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
519                         break;
520                 ret = 0;
521                 break;
522         default:
523                 ret = sys_quotactl(cmd, special, id, addr);
524         }
525         return ret;
526 }
527 #endif