quota: special case Q_SYNC without device name
[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 #include <net/netlink.h>
22 #include <net/genetlink.h>
23
24 /* Check validity of generic quotactl commands */
25 static int generic_quotactl_valid(struct super_block *sb, int type, int cmd,
26                                   qid_t id)
27 {
28         if (type >= MAXQUOTAS)
29                 return -EINVAL;
30         if (!sb && cmd != Q_SYNC)
31                 return -ENODEV;
32         /* Is operation supported? */
33         if (sb && !sb->s_qcop)
34                 return -ENOSYS;
35
36         /* Check privileges */
37         if (cmd == Q_GETQUOTA) {
38                 if (((type == USRQUOTA && current_euid() != id) ||
39                      (type == GRPQUOTA && !in_egroup_p(id))) &&
40                     !capable(CAP_SYS_ADMIN))
41                         return -EPERM;
42         }
43         else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
44                 if (!capable(CAP_SYS_ADMIN))
45                         return -EPERM;
46
47         return 0;
48 }
49
50 /* Check validity of XFS Quota Manager commands */
51 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
52                               qid_t id)
53 {
54         if (type >= XQM_MAXQUOTAS)
55                 return -EINVAL;
56         if (!sb)
57                 return -ENODEV;
58         if (!sb->s_qcop)
59                 return -ENOSYS;
60
61         /* Check privileges */
62         if (cmd == Q_XGETQUOTA) {
63                 if (((type == XQM_USRQUOTA && current_euid() != id) ||
64                      (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
65                      !capable(CAP_SYS_ADMIN))
66                         return -EPERM;
67         } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
68                 if (!capable(CAP_SYS_ADMIN))
69                         return -EPERM;
70         }
71
72         return 0;
73 }
74
75 static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
76                                 qid_t id)
77 {
78         int error;
79
80         if (XQM_COMMAND(cmd))
81                 error = xqm_quotactl_valid(sb, type, cmd, id);
82         else
83                 error = generic_quotactl_valid(sb, type, cmd, id);
84         if (!error)
85                 error = security_quotactl(cmd, type, id, sb);
86         return error;
87 }
88
89 #ifdef CONFIG_QUOTA
90 void sync_quota_sb(struct super_block *sb, int type)
91 {
92         int cnt;
93
94         if (!sb->s_qcop->quota_sync)
95                 return;
96
97         sb->s_qcop->quota_sync(sb, type);
98
99         if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
100                 return;
101         /* This is not very clever (and fast) but currently I don't know about
102          * any other simple way of getting quota data to disk and we must get
103          * them there for userspace to be visible... */
104         if (sb->s_op->sync_fs)
105                 sb->s_op->sync_fs(sb, 1);
106         sync_blockdev(sb->s_bdev);
107
108         /*
109          * Now when everything is written we can discard the pagecache so
110          * that userspace sees the changes.
111          */
112         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
113         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
114                 if (type != -1 && cnt != type)
115                         continue;
116                 if (!sb_has_quota_active(sb, cnt))
117                         continue;
118                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
119                                   I_MUTEX_QUOTA);
120                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
121                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
122         }
123         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
124 }
125 #endif
126
127 static int quota_sync_all(int type)
128 {
129         struct super_block *sb;
130         int cnt;
131         int ret;
132
133         if (type >= MAXQUOTAS)
134                 return -EINVAL;
135         ret = security_quotactl(Q_SYNC, type, 0, NULL);
136         if (ret)
137                 return ret;
138
139         spin_lock(&sb_lock);
140 restart:
141         list_for_each_entry(sb, &super_blocks, s_list) {
142                 /* This test just improves performance so it needn't be
143                  * reliable... */
144                 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
145                         if (type != -1 && type != cnt)
146                                 continue;
147                         if (!sb_has_quota_active(sb, cnt))
148                                 continue;
149                         if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
150                            list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
151                                 continue;
152                         break;
153                 }
154                 if (cnt == MAXQUOTAS)
155                         continue;
156                 sb->s_count++;
157                 spin_unlock(&sb_lock);
158                 down_read(&sb->s_umount);
159                 if (sb->s_root)
160                         sync_quota_sb(sb, type);
161                 up_read(&sb->s_umount);
162                 spin_lock(&sb_lock);
163                 if (__put_super_and_need_restart(sb))
164                         goto restart;
165         }
166         spin_unlock(&sb_lock);
167
168         return 0;
169 }
170
171 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
172                          void __user *addr)
173 {
174         char *pathname;
175         int ret = -ENOSYS;
176
177         pathname = getname(addr);
178         if (IS_ERR(pathname))
179                 return PTR_ERR(pathname);
180         if (sb->s_qcop->quota_on)
181                 ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
182         putname(pathname);
183         return ret;
184 }
185
186 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
187 {
188         __u32 fmt;
189
190         down_read(&sb_dqopt(sb)->dqptr_sem);
191         if (!sb_has_quota_active(sb, type)) {
192                 up_read(&sb_dqopt(sb)->dqptr_sem);
193                 return -ESRCH;
194         }
195         fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
196         up_read(&sb_dqopt(sb)->dqptr_sem);
197         if (copy_to_user(addr, &fmt, sizeof(fmt)))
198                 return -EFAULT;
199         return 0;
200 }
201
202 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
203 {
204         struct if_dqinfo info;
205         int ret;
206
207         if (!sb_has_quota_active(sb, type))
208                 return -ESRCH;
209         if (!sb->s_qcop->get_info)
210                 return -ENOSYS;
211         ret = sb->s_qcop->get_info(sb, type, &info);
212         if (!ret && copy_to_user(addr, &info, sizeof(info)))
213                 return -EFAULT;
214         return ret;
215 }
216
217 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
218 {
219         struct if_dqinfo info;
220
221         if (copy_from_user(&info, addr, sizeof(info)))
222                 return -EFAULT;
223         if (!sb_has_quota_active(sb, type))
224                 return -ESRCH;
225         if (!sb->s_qcop->set_info)
226                 return -ENOSYS;
227         return sb->s_qcop->set_info(sb, type, &info);
228 }
229
230 static int quota_getquota(struct super_block *sb, int type, qid_t id,
231                           void __user *addr)
232 {
233         struct if_dqblk idq;
234         int ret;
235
236         if (!sb_has_quota_active(sb, type))
237                 return -ESRCH;
238         if (!sb->s_qcop->get_dqblk)
239                 return -ENOSYS;
240         ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
241         if (ret)
242                 return ret;
243         if (copy_to_user(addr, &idq, sizeof(idq)))
244                 return -EFAULT;
245         return 0;
246 }
247
248 static int quota_setquota(struct super_block *sb, int type, qid_t id,
249                           void __user *addr)
250 {
251         struct if_dqblk idq;
252
253         if (copy_from_user(&idq, addr, sizeof(idq)))
254                 return -EFAULT;
255         if (!sb_has_quota_active(sb, type))
256                 return -ESRCH;
257         if (!sb->s_qcop->set_dqblk)
258                 return -ENOSYS;
259         return sb->s_qcop->set_dqblk(sb, type, id, &idq);
260 }
261
262 static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
263 {
264         __u32 flags;
265
266         if (copy_from_user(&flags, addr, sizeof(flags)))
267                 return -EFAULT;
268         if (!sb->s_qcop->set_xstate)
269                 return -ENOSYS;
270         return sb->s_qcop->set_xstate(sb, flags, cmd);
271 }
272
273 static int quota_getxstate(struct super_block *sb, void __user *addr)
274 {
275         struct fs_quota_stat fqs;
276         int ret;
277
278         if (!sb->s_qcop->get_xstate)
279                 return -ENOSYS;
280         ret = sb->s_qcop->get_xstate(sb, &fqs);
281         if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
282                 return -EFAULT;
283         return ret;
284 }
285
286 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
287                            void __user *addr)
288 {
289         struct fs_disk_quota fdq;
290
291         if (copy_from_user(&fdq, addr, sizeof(fdq)))
292                 return -EFAULT;
293         if (!sb->s_qcop->set_xquota)
294                 return -ENOSYS;
295         return sb->s_qcop->set_xquota(sb, type, id, &fdq);
296 }
297
298 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
299                            void __user *addr)
300 {
301         struct fs_disk_quota fdq;
302         int ret;
303
304         if (!sb->s_qcop->get_xquota)
305                 return -ENOSYS;
306         ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
307         if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
308                 return -EFAULT;
309         return ret;
310 }
311
312 /* Copy parameters and call proper function */
313 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
314                        void __user *addr)
315 {
316         switch (cmd) {
317         case Q_QUOTAON:
318                 return quota_quotaon(sb, type, cmd, id, addr);
319         case Q_QUOTAOFF:
320                 if (!sb->s_qcop->quota_off)
321                         return -ENOSYS;
322                 return sb->s_qcop->quota_off(sb, type, 0);
323         case Q_GETFMT:
324                 return quota_getfmt(sb, type, addr);
325         case Q_GETINFO:
326                 return quota_getinfo(sb, type, addr);
327         case Q_SETINFO:
328                 return quota_setinfo(sb, type, addr);
329         case Q_GETQUOTA:
330                 return quota_getquota(sb, type, id, addr);
331         case Q_SETQUOTA:
332                 return quota_setquota(sb, type, id, addr);
333         case Q_SYNC:
334                 if (!sb->s_qcop->quota_sync)
335                         return -ENOSYS;
336                 sync_quota_sb(sb, type);
337                 return 0;
338         case Q_XQUOTAON:
339         case Q_XQUOTAOFF:
340         case Q_XQUOTARM:
341                 return quota_setxstate(sb, cmd, addr);
342         case Q_XGETQSTAT:
343                 return quota_getxstate(sb, addr);
344         case Q_XSETQLIM:
345                 return quota_setxquota(sb, type, id, addr);
346         case Q_XGETQUOTA:
347                 return quota_getxquota(sb, type, id, addr);
348         case Q_XQUOTASYNC:
349                 if (!sb->s_qcop->quota_sync)
350                         return -ENOSYS;
351                 return sb->s_qcop->quota_sync(sb, type);
352         default:
353                 return -EINVAL;
354         }
355 }
356
357 /*
358  * look up a superblock on which quota ops will be performed
359  * - use the name of a block device to find the superblock thereon
360  */
361 static struct super_block *quotactl_block(const char __user *special)
362 {
363 #ifdef CONFIG_BLOCK
364         struct block_device *bdev;
365         struct super_block *sb;
366         char *tmp = getname(special);
367
368         if (IS_ERR(tmp))
369                 return ERR_CAST(tmp);
370         bdev = lookup_bdev(tmp);
371         putname(tmp);
372         if (IS_ERR(bdev))
373                 return ERR_CAST(bdev);
374         sb = get_super(bdev);
375         bdput(bdev);
376         if (!sb)
377                 return ERR_PTR(-ENODEV);
378
379         return sb;
380 #else
381         return ERR_PTR(-ENODEV);
382 #endif
383 }
384
385 /*
386  * This is the system call interface. This communicates with
387  * the user-level programs. Currently this only supports diskquota
388  * calls. Maybe we need to add the process quotas etc. in the future,
389  * but we probably should use rlimits for that.
390  */
391 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
392                 qid_t, id, void __user *, addr)
393 {
394         uint cmds, type;
395         struct super_block *sb = NULL;
396         int ret;
397
398         cmds = cmd >> SUBCMDSHIFT;
399         type = cmd & SUBCMDMASK;
400
401         /*
402          * As a special case Q_SYNC can be called without a specific device.
403          * It will iterate all superblocks that have quota enabled and call
404          * the sync action on each of them.
405          */
406         if (!special) {
407                 if (cmds == Q_SYNC)
408                         return quota_sync_all(type);
409                 return -ENODEV;
410         }
411
412         sb = quotactl_block(special);
413         if (IS_ERR(sb))
414                 return PTR_ERR(sb);
415
416         ret = check_quotactl_valid(sb, type, cmds, id);
417         if (ret >= 0)
418                 ret = do_quotactl(sb, type, cmds, id, addr);
419
420         drop_super(sb);
421         return ret;
422 }
423
424 #if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
425 /*
426  * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
427  * and is necessary due to alignment problems.
428  */
429 struct compat_if_dqblk {
430         compat_u64 dqb_bhardlimit;
431         compat_u64 dqb_bsoftlimit;
432         compat_u64 dqb_curspace;
433         compat_u64 dqb_ihardlimit;
434         compat_u64 dqb_isoftlimit;
435         compat_u64 dqb_curinodes;
436         compat_u64 dqb_btime;
437         compat_u64 dqb_itime;
438         compat_uint_t dqb_valid;
439 };
440
441 /* XFS structures */
442 struct compat_fs_qfilestat {
443         compat_u64 dqb_bhardlimit;
444         compat_u64 qfs_nblks;
445         compat_uint_t qfs_nextents;
446 };
447
448 struct compat_fs_quota_stat {
449         __s8            qs_version;
450         __u16           qs_flags;
451         __s8            qs_pad;
452         struct compat_fs_qfilestat      qs_uquota;
453         struct compat_fs_qfilestat      qs_gquota;
454         compat_uint_t   qs_incoredqs;
455         compat_int_t    qs_btimelimit;
456         compat_int_t    qs_itimelimit;
457         compat_int_t    qs_rtbtimelimit;
458         __u16           qs_bwarnlimit;
459         __u16           qs_iwarnlimit;
460 };
461
462 asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
463                                                 qid_t id, void __user *addr)
464 {
465         unsigned int cmds;
466         struct if_dqblk __user *dqblk;
467         struct compat_if_dqblk __user *compat_dqblk;
468         struct fs_quota_stat __user *fsqstat;
469         struct compat_fs_quota_stat __user *compat_fsqstat;
470         compat_uint_t data;
471         u16 xdata;
472         long ret;
473
474         cmds = cmd >> SUBCMDSHIFT;
475
476         switch (cmds) {
477         case Q_GETQUOTA:
478                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
479                 compat_dqblk = addr;
480                 ret = sys_quotactl(cmd, special, id, dqblk);
481                 if (ret)
482                         break;
483                 if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
484                         get_user(data, &dqblk->dqb_valid) ||
485                         put_user(data, &compat_dqblk->dqb_valid))
486                         ret = -EFAULT;
487                 break;
488         case Q_SETQUOTA:
489                 dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
490                 compat_dqblk = addr;
491                 ret = -EFAULT;
492                 if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
493                         get_user(data, &compat_dqblk->dqb_valid) ||
494                         put_user(data, &dqblk->dqb_valid))
495                         break;
496                 ret = sys_quotactl(cmd, special, id, dqblk);
497                 break;
498         case Q_XGETQSTAT:
499                 fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
500                 compat_fsqstat = addr;
501                 ret = sys_quotactl(cmd, special, id, fsqstat);
502                 if (ret)
503                         break;
504                 ret = -EFAULT;
505                 /* Copying qs_version, qs_flags, qs_pad */
506                 if (copy_in_user(compat_fsqstat, fsqstat,
507                         offsetof(struct compat_fs_quota_stat, qs_uquota)))
508                         break;
509                 /* Copying qs_uquota */
510                 if (copy_in_user(&compat_fsqstat->qs_uquota,
511                         &fsqstat->qs_uquota,
512                         sizeof(compat_fsqstat->qs_uquota)) ||
513                         get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
514                         put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
515                         break;
516                 /* Copying qs_gquota */
517                 if (copy_in_user(&compat_fsqstat->qs_gquota,
518                         &fsqstat->qs_gquota,
519                         sizeof(compat_fsqstat->qs_gquota)) ||
520                         get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
521                         put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
522                         break;
523                 /* Copying the rest */
524                 if (copy_in_user(&compat_fsqstat->qs_incoredqs,
525                         &fsqstat->qs_incoredqs,
526                         sizeof(struct compat_fs_quota_stat) -
527                         offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
528                         get_user(xdata, &fsqstat->qs_iwarnlimit) ||
529                         put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
530                         break;
531                 ret = 0;
532                 break;
533         default:
534                 ret = sys_quotactl(cmd, special, id, addr);
535         }
536         return ret;
537 }
538 #endif
539
540
541 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
542
543 /* Netlink family structure for quota */
544 static struct genl_family quota_genl_family = {
545         .id = GENL_ID_GENERATE,
546         .hdrsize = 0,
547         .name = "VFS_DQUOT",
548         .version = 1,
549         .maxattr = QUOTA_NL_A_MAX,
550 };
551
552 /**
553  * quota_send_warning - Send warning to userspace about exceeded quota
554  * @type: The quota type: USRQQUOTA, GRPQUOTA,...
555  * @id: The user or group id of the quota that was exceeded
556  * @dev: The device on which the fs is mounted (sb->s_dev)
557  * @warntype: The type of the warning: QUOTA_NL_...
558  *
559  * This can be used by filesystems (including those which don't use
560  * dquot) to send a message to userspace relating to quota limits.
561  *
562  */
563
564 void quota_send_warning(short type, unsigned int id, dev_t dev,
565                         const char warntype)
566 {
567         static atomic_t seq;
568         struct sk_buff *skb;
569         void *msg_head;
570         int ret;
571         int msg_size = 4 * nla_total_size(sizeof(u32)) +
572                        2 * nla_total_size(sizeof(u64));
573
574         /* We have to allocate using GFP_NOFS as we are called from a
575          * filesystem performing write and thus further recursion into
576          * the fs to free some data could cause deadlocks. */
577         skb = genlmsg_new(msg_size, GFP_NOFS);
578         if (!skb) {
579                 printk(KERN_ERR
580                   "VFS: Not enough memory to send quota warning.\n");
581                 return;
582         }
583         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
584                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
585         if (!msg_head) {
586                 printk(KERN_ERR
587                   "VFS: Cannot store netlink header in quota warning.\n");
588                 goto err_out;
589         }
590         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type);
591         if (ret)
592                 goto attr_err_out;
593         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id);
594         if (ret)
595                 goto attr_err_out;
596         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
597         if (ret)
598                 goto attr_err_out;
599         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
600         if (ret)
601                 goto attr_err_out;
602         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
603         if (ret)
604                 goto attr_err_out;
605         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
606         if (ret)
607                 goto attr_err_out;
608         genlmsg_end(skb, msg_head);
609
610         genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
611         return;
612 attr_err_out:
613         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
614 err_out:
615         kfree_skb(skb);
616 }
617 EXPORT_SYMBOL(quota_send_warning);
618
619 static int __init quota_init(void)
620 {
621         if (genl_register_family(&quota_genl_family) != 0)
622                 printk(KERN_ERR
623                        "VFS: Failed to create quota netlink interface.\n");
624         return 0;
625 };
626
627 module_init(quota_init);
628 #endif
629