mac80211: move QOS control helpers into ieee80211.h
[linux-2.6] / 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_SETINFO:
73                 case Q_SETQUOTA:
74                 case Q_GETQUOTA:
75                         /* This is just informative test so we are satisfied without a lock */
76                         if (!sb_has_quota_enabled(sb, type))
77                                 return -ESRCH;
78         }
79
80         /* Check privileges */
81         if (cmd == Q_GETQUOTA) {
82                 if (((type == USRQUOTA && current->euid != id) ||
83                      (type == GRPQUOTA && !in_egroup_p(id))) &&
84                     !capable(CAP_SYS_ADMIN))
85                         return -EPERM;
86         }
87         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
88                 if (!capable(CAP_SYS_ADMIN))
89                         return -EPERM;
90
91         return 0;
92 }
93
94 /* Check validity of XFS Quota Manager commands */
95 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
96 {
97         if (type >= XQM_MAXQUOTAS)
98                 return -EINVAL;
99         if (!sb)
100                 return -ENODEV;
101         if (!sb->s_qcop)
102                 return -ENOSYS;
103
104         switch (cmd) {
105                 case Q_XQUOTAON:
106                 case Q_XQUOTAOFF:
107                 case Q_XQUOTARM:
108                         if (!sb->s_qcop->set_xstate)
109                                 return -ENOSYS;
110                         break;
111                 case Q_XGETQSTAT:
112                         if (!sb->s_qcop->get_xstate)
113                                 return -ENOSYS;
114                         break;
115                 case Q_XSETQLIM:
116                         if (!sb->s_qcop->set_xquota)
117                                 return -ENOSYS;
118                         break;
119                 case Q_XGETQUOTA:
120                         if (!sb->s_qcop->get_xquota)
121                                 return -ENOSYS;
122                         break;
123                 case Q_XQUOTASYNC:
124                         if (!sb->s_qcop->quota_sync)
125                                 return -ENOSYS;
126                         break;
127                 default:
128                         return -EINVAL;
129         }
130
131         /* Check privileges */
132         if (cmd == Q_XGETQUOTA) {
133                 if (((type == XQM_USRQUOTA && current->euid != id) ||
134                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
135                      !capable(CAP_SYS_ADMIN))
136                         return -EPERM;
137         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
138                 if (!capable(CAP_SYS_ADMIN))
139                         return -EPERM;
140         }
141
142         return 0;
143 }
144
145 static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
146 {
147         int error;
148
149         if (XQM_COMMAND(cmd))
150                 error = xqm_quotactl_valid(sb, type, cmd, id);
151         else
152                 error = generic_quotactl_valid(sb, type, cmd, id);
153         if (!error)
154                 error = security_quotactl(cmd, type, id, sb);
155         return error;
156 }
157
158 static void quota_sync_sb(struct super_block *sb, int type)
159 {
160         int cnt;
161
162         sb->s_qcop->quota_sync(sb, type);
163         /* This is not very clever (and fast) but currently I don't know about
164          * any other simple way of getting quota data to disk and we must get
165          * them there for userspace to be visible... */
166         if (sb->s_op->sync_fs)
167                 sb->s_op->sync_fs(sb, 1);
168         sync_blockdev(sb->s_bdev);
169
170         /*
171          * Now when everything is written we can discard the pagecache so
172          * that userspace sees the changes.
173          */
174         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
175         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
176                 if (type != -1 && cnt != type)
177                         continue;
178                 if (!sb_has_quota_enabled(sb, cnt))
179                         continue;
180                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
181                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
182                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
183         }
184         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
185 }
186
187 void sync_dquots(struct super_block *sb, int type)
188 {
189         int cnt, dirty;
190
191         if (sb) {
192                 if (sb->s_qcop->quota_sync)
193                         quota_sync_sb(sb, type);
194                 return;
195         }
196
197         spin_lock(&sb_lock);
198 restart:
199         list_for_each_entry(sb, &super_blocks, s_list) {
200                 /* This test just improves performance so it needn't be reliable... */
201                 for (cnt = 0, dirty = 0; cnt < MAXQUOTAS; cnt++)
202                         if ((type == cnt || type == -1) && sb_has_quota_enabled(sb, cnt)
203                             && info_any_dirty(&sb_dqopt(sb)->info[cnt]))
204                                 dirty = 1;
205                 if (!dirty)
206                         continue;
207                 sb->s_count++;
208                 spin_unlock(&sb_lock);
209                 down_read(&sb->s_umount);
210                 if (sb->s_root && sb->s_qcop->quota_sync)
211                         quota_sync_sb(sb, type);
212                 up_read(&sb->s_umount);
213                 spin_lock(&sb_lock);
214                 if (__put_super_and_need_restart(sb))
215                         goto restart;
216         }
217         spin_unlock(&sb_lock);
218 }
219
220 /* Copy parameters and call proper function */
221 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
222 {
223         int ret;
224
225         switch (cmd) {
226                 case Q_QUOTAON: {
227                         char *pathname;
228
229                         if (IS_ERR(pathname = getname(addr)))
230                                 return PTR_ERR(pathname);
231                         ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
232                         putname(pathname);
233                         return ret;
234                 }
235                 case Q_QUOTAOFF:
236                         return sb->s_qcop->quota_off(sb, type, 0);
237
238                 case Q_GETFMT: {
239                         __u32 fmt;
240
241                         down_read(&sb_dqopt(sb)->dqptr_sem);
242                         if (!sb_has_quota_enabled(sb, type)) {
243                                 up_read(&sb_dqopt(sb)->dqptr_sem);
244                                 return -ESRCH;
245                         }
246                         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
247                         up_read(&sb_dqopt(sb)->dqptr_sem);
248                         if (copy_to_user(addr, &fmt, sizeof(fmt)))
249                                 return -EFAULT;
250                         return 0;
251                 }
252                 case Q_GETINFO: {
253                         struct if_dqinfo info;
254
255                         if ((ret = sb->s_qcop->get_info(sb, type, &info)))
256                                 return ret;
257                         if (copy_to_user(addr, &info, sizeof(info)))
258                                 return -EFAULT;
259                         return 0;
260                 }
261                 case Q_SETINFO: {
262                         struct if_dqinfo info;
263
264                         if (copy_from_user(&info, addr, sizeof(info)))
265                                 return -EFAULT;
266                         return sb->s_qcop->set_info(sb, type, &info);
267                 }
268                 case Q_GETQUOTA: {
269                         struct if_dqblk idq;
270
271                         if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
272                                 return ret;
273                         if (copy_to_user(addr, &idq, sizeof(idq)))
274                                 return -EFAULT;
275                         return 0;
276                 }
277                 case Q_SETQUOTA: {
278                         struct if_dqblk idq;
279
280                         if (copy_from_user(&idq, addr, sizeof(idq)))
281                                 return -EFAULT;
282                         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
283                 }
284                 case Q_SYNC:
285                         sync_dquots(sb, type);
286                         return 0;
287
288                 case Q_XQUOTAON:
289                 case Q_XQUOTAOFF:
290                 case Q_XQUOTARM: {
291                         __u32 flags;
292
293                         if (copy_from_user(&flags, addr, sizeof(flags)))
294                                 return -EFAULT;
295                         return sb->s_qcop->set_xstate(sb, flags, cmd);
296                 }
297                 case Q_XGETQSTAT: {
298                         struct fs_quota_stat fqs;
299                 
300                         if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
301                                 return ret;
302                         if (copy_to_user(addr, &fqs, sizeof(fqs)))
303                                 return -EFAULT;
304                         return 0;
305                 }
306                 case Q_XSETQLIM: {
307                         struct fs_disk_quota fdq;
308
309                         if (copy_from_user(&fdq, addr, sizeof(fdq)))
310                                 return -EFAULT;
311                        return sb->s_qcop->set_xquota(sb, type, id, &fdq);
312                 }
313                 case Q_XGETQUOTA: {
314                         struct fs_disk_quota fdq;
315
316                         if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
317                                 return ret;
318                         if (copy_to_user(addr, &fdq, sizeof(fdq)))
319                                 return -EFAULT;
320                         return 0;
321                 }
322                 case Q_XQUOTASYNC:
323                         return sb->s_qcop->quota_sync(sb, type);
324                 /* We never reach here unless validity check is broken */
325                 default:
326                         BUG();
327         }
328         return 0;
329 }
330
331 /*
332  * look up a superblock on which quota ops will be performed
333  * - use the name of a block device to find the superblock thereon
334  */
335 static inline struct super_block *quotactl_block(const char __user *special)
336 {
337 #ifdef CONFIG_BLOCK
338         struct block_device *bdev;
339         struct super_block *sb;
340         char *tmp = getname(special);
341
342         if (IS_ERR(tmp))
343                 return ERR_CAST(tmp);
344         bdev = lookup_bdev(tmp);
345         putname(tmp);
346         if (IS_ERR(bdev))
347                 return ERR_CAST(bdev);
348         sb = get_super(bdev);
349         bdput(bdev);
350         if (!sb)
351                 return ERR_PTR(-ENODEV);
352
353         return sb;
354 #else
355         return ERR_PTR(-ENODEV);
356 #endif
357 }
358
359 /*
360  * This is the system call interface. This communicates with
361  * the user-level programs. Currently this only supports diskquota
362  * calls. Maybe we need to add the process quotas etc. in the future,
363  * but we probably should use rlimits for that.
364  */
365 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
366 {
367         uint cmds, type;
368         struct super_block *sb = NULL;
369         int ret;
370
371         cmds = cmd >> SUBCMDSHIFT;
372         type = cmd & SUBCMDMASK;
373
374         if (cmds != Q_SYNC || special) {
375                 sb = quotactl_block(special);
376                 if (IS_ERR(sb))
377                         return PTR_ERR(sb);
378         }
379
380         ret = check_quotactl_valid(sb, type, cmds, id);
381         if (ret >= 0)
382                 ret = do_quotactl(sb, type, cmds, id, addr);
383         if (sb)
384                 drop_super(sb);
385
386         return ret;
387 }
388
389 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
390 /*
391  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
392  * and is necessary due to alignment problems.
393  */
394 struct compat_if_dqblk {
395         compat_u64 dqb_bhardlimit;
396         compat_u64 dqb_bsoftlimit;
397         compat_u64 dqb_curspace;
398         compat_u64 dqb_ihardlimit;
399         compat_u64 dqb_isoftlimit;
400         compat_u64 dqb_curinodes;
401         compat_u64 dqb_btime;
402         compat_u64 dqb_itime;
403         compat_uint_t dqb_valid;
404 };
405
406 /* XFS structures */
407 struct compat_fs_qfilestat {
408         compat_u64 dqb_bhardlimit;
409         compat_u64 qfs_nblks;
410         compat_uint_t qfs_nextents;
411 };
412
413 struct compat_fs_quota_stat {
414         __s8            qs_version;
415         __u16           qs_flags;
416         __s8            qs_pad;
417         struct compat_fs_qfilestat      qs_uquota;
418         struct compat_fs_qfilestat      qs_gquota;
419         compat_uint_t   qs_incoredqs;
420         compat_int_t    qs_btimelimit;
421         compat_int_t    qs_itimelimit;
422         compat_int_t    qs_rtbtimelimit;
423         __u16           qs_bwarnlimit;
424         __u16           qs_iwarnlimit;
425 };
426
427 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
428                                                 qid_t id, void __user *addr)
429 {
430         unsigned int cmds;
431         struct if_dqblk __user *dqblk;
432         struct compat_if_dqblk __user *compat_dqblk;
433         struct fs_quota_stat __user *fsqstat;
434         struct compat_fs_quota_stat __user *compat_fsqstat;
435         compat_uint_t data;
436         u16 xdata;
437         long ret;
438
439         cmds = cmd >> SUBCMDSHIFT;
440
441         switch (cmds) {
442         case Q_GETQUOTA:
443                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
444                 compat_dqblk = addr;
445                 ret = sys_quotactl(cmd, special, id, dqblk);
446                 if (ret)
447                         break;
448                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
449                         get_user(data, &dqblk->dqb_valid) ||
450                         put_user(data, &compat_dqblk->dqb_valid))
451                         ret = -EFAULT;
452                 break;
453         case Q_SETQUOTA:
454                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
455                 compat_dqblk = addr;
456                 ret = -EFAULT;
457                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
458                         get_user(data, &compat_dqblk->dqb_valid) ||
459                         put_user(data, &dqblk->dqb_valid))
460                         break;
461                 ret = sys_quotactl(cmd, special, id, dqblk);
462                 break;
463         case Q_XGETQSTAT:
464                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
465                 compat_fsqstat = addr;
466                 ret = sys_quotactl(cmd, special, id, fsqstat);
467                 if (ret)
468                         break;
469                 ret = -EFAULT;
470                 /* Copying qs_version, qs_flags, qs_pad */
471                 if (copy_in_user(compat_fsqstat, fsqstat,
472                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
473                         break;
474                 /* Copying qs_uquota */
475                 if (copy_in_user(&compat_fsqstat->qs_uquota,
476                         &fsqstat->qs_uquota,
477                         sizeof(compat_fsqstat->qs_uquota)) ||
478                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
479                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
480                         break;
481                 /* Copying qs_gquota */
482                 if (copy_in_user(&compat_fsqstat->qs_gquota,
483                         &fsqstat->qs_gquota,
484                         sizeof(compat_fsqstat->qs_gquota)) ||
485                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
486                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
487                         break;
488                 /* Copying the rest */
489                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
490                         &fsqstat->qs_incoredqs,
491                         sizeof(struct compat_fs_quota_stat) -
492                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
493                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
494                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
495                         break;
496                 ret = 0;
497                 break;
498         default:
499                 ret = sys_quotactl(cmd, special, id, addr);
500         }
501         return ret;
502 }
503 #endif