Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p)
[linux-2.6.git] / 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_CAST(tmp);
345         bdev = lookup_bdev(tmp);
346         putname(tmp);
347         if (IS_ERR(bdev))
348                 return ERR_CAST(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_COMPAT_FOR_U64_ALIGNMENT)
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