VFS: Export dquot_send_warning
[linux-2.6.git] / fs / quota / dquot.c
1 /*
2  * Implementation of the diskquota system for the LINUX operating system. QUOTA
3  * is implemented using the BSD system call interface as the means of
4  * communication with the user level. This file contains the generic routines
5  * called by the different filesystems on allocation of an inode or block.
6  * These routines take care of the administration needed to have a consistent
7  * diskquota tracking system. The ideas of both user and group quotas are based
8  * on the Melbourne quota system as used on BSD derived systems. The internal
9  * implementation is based on one of the several variants of the LINUX
10  * inode-subsystem with added complexity of the diskquota system.
11  * 
12  * Author:      Marco van Wieringen <mvw@planets.elm.net>
13  *
14  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
15  *
16  *              Revised list management to avoid races
17  *              -- Bill Hawes, <whawes@star.net>, 9/98
18  *
19  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
20  *              As the consequence the locking was moved from dquot_decr_...(),
21  *              dquot_incr_...() to calling functions.
22  *              invalidate_dquots() now writes modified dquots.
23  *              Serialized quota_off() and quota_on() for mount point.
24  *              Fixed a few bugs in grow_dquots().
25  *              Fixed deadlock in write_dquot() - we no longer account quotas on
26  *              quota files
27  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
28  *              add_dquot_ref() restarts after blocking
29  *              Added check for bogus uid and fixed check for group in quotactl.
30  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
31  *
32  *              Used struct list_head instead of own list struct
33  *              Invalidation of referenced dquots is no longer possible
34  *              Improved free_dquots list management
35  *              Quota and i_blocks are now updated in one place to avoid races
36  *              Warnings are now delayed so we won't block in critical section
37  *              Write updated not to require dquot lock
38  *              Jan Kara, <jack@suse.cz>, 9/2000
39  *
40  *              Added dynamic quota structure allocation
41  *              Jan Kara <jack@suse.cz> 12/2000
42  *
43  *              Rewritten quota interface. Implemented new quota format and
44  *              formats registering.
45  *              Jan Kara, <jack@suse.cz>, 2001,2002
46  *
47  *              New SMP locking.
48  *              Jan Kara, <jack@suse.cz>, 10/2002
49  *
50  *              Added journalled quota support, fix lock inversion problems
51  *              Jan Kara, <jack@suse.cz>, 2003,2004
52  *
53  * (C) Copyright 1994 - 1997 Marco van Wieringen 
54  */
55
56 #include <linux/errno.h>
57 #include <linux/kernel.h>
58 #include <linux/fs.h>
59 #include <linux/mount.h>
60 #include <linux/mm.h>
61 #include <linux/time.h>
62 #include <linux/types.h>
63 #include <linux/string.h>
64 #include <linux/fcntl.h>
65 #include <linux/stat.h>
66 #include <linux/tty.h>
67 #include <linux/file.h>
68 #include <linux/slab.h>
69 #include <linux/sysctl.h>
70 #include <linux/init.h>
71 #include <linux/module.h>
72 #include <linux/proc_fs.h>
73 #include <linux/security.h>
74 #include <linux/kmod.h>
75 #include <linux/namei.h>
76 #include <linux/buffer_head.h>
77 #include <linux/capability.h>
78 #include <linux/quotaops.h>
79 #include <linux/writeback.h> /* for inode_lock, oddly enough.. */
80
81 #include <asm/uaccess.h>
82
83 #define __DQUOT_PARANOIA
84
85 /*
86  * There are three quota SMP locks. dq_list_lock protects all lists with quotas
87  * and quota formats, dqstats structure containing statistics about the lists
88  * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
89  * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
90  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
91  * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
92  * modifications of quota state (on quotaon and quotaoff) and readers who care
93  * about latest values take it as well.
94  *
95  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
96  *   dq_list_lock > dq_state_lock
97  *
98  * Note that some things (eg. sb pointer, type, id) doesn't change during
99  * the life of the dquot structure and so needn't to be protected by a lock
100  *
101  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
102  * operation is just reading pointers from inode (or not using them at all) the
103  * read lock is enough. If pointers are altered function must hold write lock
104  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
105  * for altering the flag i_mutex is also needed).
106  *
107  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
108  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
109  * Currently dquot is locked only when it is being read to memory (or space for
110  * it is being allocated) on the first dqget() and when it is being released on
111  * the last dqput(). The allocation and release oparations are serialized by
112  * the dq_lock and by checking the use count in dquot_release().  Write
113  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
114  * spinlock to internal buffers before writing.
115  *
116  * Lock ordering (including related VFS locks) is the following:
117  *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
118  *   dqio_mutex
119  * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
120  * dqptr_sem. But filesystem has to count with the fact that functions such as
121  * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
122  * from inside a transaction to keep filesystem consistency after a crash. Also
123  * filesystems usually want to do some IO on dquot from ->mark_dirty which is
124  * called with dqptr_sem held.
125  * i_mutex on quota files is special (it's below dqio_mutex)
126  */
127
128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
129 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
130 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
131 EXPORT_SYMBOL(dq_data_lock);
132
133 static char *quotatypes[] = INITQFNAMES;
134 static struct quota_format_type *quota_formats; /* List of registered formats */
135 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
136
137 /* SLAB cache for dquot structures */
138 static struct kmem_cache *dquot_cachep;
139
140 int register_quota_format(struct quota_format_type *fmt)
141 {
142         spin_lock(&dq_list_lock);
143         fmt->qf_next = quota_formats;
144         quota_formats = fmt;
145         spin_unlock(&dq_list_lock);
146         return 0;
147 }
148 EXPORT_SYMBOL(register_quota_format);
149
150 void unregister_quota_format(struct quota_format_type *fmt)
151 {
152         struct quota_format_type **actqf;
153
154         spin_lock(&dq_list_lock);
155         for (actqf = &quota_formats; *actqf && *actqf != fmt;
156              actqf = &(*actqf)->qf_next)
157                 ;
158         if (*actqf)
159                 *actqf = (*actqf)->qf_next;
160         spin_unlock(&dq_list_lock);
161 }
162 EXPORT_SYMBOL(unregister_quota_format);
163
164 static struct quota_format_type *find_quota_format(int id)
165 {
166         struct quota_format_type *actqf;
167
168         spin_lock(&dq_list_lock);
169         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
170              actqf = actqf->qf_next)
171                 ;
172         if (!actqf || !try_module_get(actqf->qf_owner)) {
173                 int qm;
174
175                 spin_unlock(&dq_list_lock);
176                 
177                 for (qm = 0; module_names[qm].qm_fmt_id &&
178                              module_names[qm].qm_fmt_id != id; qm++)
179                         ;
180                 if (!module_names[qm].qm_fmt_id ||
181                     request_module(module_names[qm].qm_mod_name))
182                         return NULL;
183
184                 spin_lock(&dq_list_lock);
185                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
186                      actqf = actqf->qf_next)
187                         ;
188                 if (actqf && !try_module_get(actqf->qf_owner))
189                         actqf = NULL;
190         }
191         spin_unlock(&dq_list_lock);
192         return actqf;
193 }
194
195 static void put_quota_format(struct quota_format_type *fmt)
196 {
197         module_put(fmt->qf_owner);
198 }
199
200 /*
201  * Dquot List Management:
202  * The quota code uses three lists for dquot management: the inuse_list,
203  * free_dquots, and dquot_hash[] array. A single dquot structure may be
204  * on all three lists, depending on its current state.
205  *
206  * All dquots are placed to the end of inuse_list when first created, and this
207  * list is used for invalidate operation, which must look at every dquot.
208  *
209  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
210  * and this list is searched whenever we need an available dquot.  Dquots are
211  * removed from the list as soon as they are used again, and
212  * dqstats.free_dquots gives the number of dquots on the list. When
213  * dquot is invalidated it's completely released from memory.
214  *
215  * Dquots with a specific identity (device, type and id) are placed on
216  * one of the dquot_hash[] hash chains. The provides an efficient search
217  * mechanism to locate a specific dquot.
218  */
219
220 static LIST_HEAD(inuse_list);
221 static LIST_HEAD(free_dquots);
222 static unsigned int dq_hash_bits, dq_hash_mask;
223 static struct hlist_head *dquot_hash;
224
225 struct dqstats dqstats;
226 EXPORT_SYMBOL(dqstats);
227
228 static inline unsigned int
229 hashfn(const struct super_block *sb, unsigned int id, int type)
230 {
231         unsigned long tmp;
232
233         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
234         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
235 }
236
237 /*
238  * Following list functions expect dq_list_lock to be held
239  */
240 static inline void insert_dquot_hash(struct dquot *dquot)
241 {
242         struct hlist_head *head;
243         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
244         hlist_add_head(&dquot->dq_hash, head);
245 }
246
247 static inline void remove_dquot_hash(struct dquot *dquot)
248 {
249         hlist_del_init(&dquot->dq_hash);
250 }
251
252 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
253                                 unsigned int id, int type)
254 {
255         struct hlist_node *node;
256         struct dquot *dquot;
257
258         hlist_for_each (node, dquot_hash+hashent) {
259                 dquot = hlist_entry(node, struct dquot, dq_hash);
260                 if (dquot->dq_sb == sb && dquot->dq_id == id &&
261                     dquot->dq_type == type)
262                         return dquot;
263         }
264         return NULL;
265 }
266
267 /* Add a dquot to the tail of the free list */
268 static inline void put_dquot_last(struct dquot *dquot)
269 {
270         list_add_tail(&dquot->dq_free, &free_dquots);
271         dqstats.free_dquots++;
272 }
273
274 static inline void remove_free_dquot(struct dquot *dquot)
275 {
276         if (list_empty(&dquot->dq_free))
277                 return;
278         list_del_init(&dquot->dq_free);
279         dqstats.free_dquots--;
280 }
281
282 static inline void put_inuse(struct dquot *dquot)
283 {
284         /* We add to the back of inuse list so we don't have to restart
285          * when traversing this list and we block */
286         list_add_tail(&dquot->dq_inuse, &inuse_list);
287         dqstats.allocated_dquots++;
288 }
289
290 static inline void remove_inuse(struct dquot *dquot)
291 {
292         dqstats.allocated_dquots--;
293         list_del(&dquot->dq_inuse);
294 }
295 /*
296  * End of list functions needing dq_list_lock
297  */
298
299 static void wait_on_dquot(struct dquot *dquot)
300 {
301         mutex_lock(&dquot->dq_lock);
302         mutex_unlock(&dquot->dq_lock);
303 }
304
305 static inline int dquot_dirty(struct dquot *dquot)
306 {
307         return test_bit(DQ_MOD_B, &dquot->dq_flags);
308 }
309
310 static inline int mark_dquot_dirty(struct dquot *dquot)
311 {
312         return dquot->dq_sb->dq_op->mark_dirty(dquot);
313 }
314
315 int dquot_mark_dquot_dirty(struct dquot *dquot)
316 {
317         spin_lock(&dq_list_lock);
318         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
319                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
320                                 info[dquot->dq_type].dqi_dirty_list);
321         spin_unlock(&dq_list_lock);
322         return 0;
323 }
324 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
325
326 /* This function needs dq_list_lock */
327 static inline int clear_dquot_dirty(struct dquot *dquot)
328 {
329         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
330                 return 0;
331         list_del_init(&dquot->dq_dirty);
332         return 1;
333 }
334
335 void mark_info_dirty(struct super_block *sb, int type)
336 {
337         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
338 }
339 EXPORT_SYMBOL(mark_info_dirty);
340
341 /*
342  *      Read dquot from disk and alloc space for it
343  */
344
345 int dquot_acquire(struct dquot *dquot)
346 {
347         int ret = 0, ret2 = 0;
348         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
349
350         mutex_lock(&dquot->dq_lock);
351         mutex_lock(&dqopt->dqio_mutex);
352         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
353                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
354         if (ret < 0)
355                 goto out_iolock;
356         set_bit(DQ_READ_B, &dquot->dq_flags);
357         /* Instantiate dquot if needed */
358         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
359                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
360                 /* Write the info if needed */
361                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
362                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
363                                                 dquot->dq_sb, dquot->dq_type);
364                 }
365                 if (ret < 0)
366                         goto out_iolock;
367                 if (ret2 < 0) {
368                         ret = ret2;
369                         goto out_iolock;
370                 }
371         }
372         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
373 out_iolock:
374         mutex_unlock(&dqopt->dqio_mutex);
375         mutex_unlock(&dquot->dq_lock);
376         return ret;
377 }
378 EXPORT_SYMBOL(dquot_acquire);
379
380 /*
381  *      Write dquot to disk
382  */
383 int dquot_commit(struct dquot *dquot)
384 {
385         int ret = 0, ret2 = 0;
386         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
387
388         mutex_lock(&dqopt->dqio_mutex);
389         spin_lock(&dq_list_lock);
390         if (!clear_dquot_dirty(dquot)) {
391                 spin_unlock(&dq_list_lock);
392                 goto out_sem;
393         }
394         spin_unlock(&dq_list_lock);
395         /* Inactive dquot can be only if there was error during read/init
396          * => we have better not writing it */
397         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
398                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
399                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
400                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
401                                                 dquot->dq_sb, dquot->dq_type);
402                 }
403                 if (ret >= 0)
404                         ret = ret2;
405         }
406 out_sem:
407         mutex_unlock(&dqopt->dqio_mutex);
408         return ret;
409 }
410 EXPORT_SYMBOL(dquot_commit);
411
412 /*
413  *      Release dquot
414  */
415 int dquot_release(struct dquot *dquot)
416 {
417         int ret = 0, ret2 = 0;
418         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
419
420         mutex_lock(&dquot->dq_lock);
421         /* Check whether we are not racing with some other dqget() */
422         if (atomic_read(&dquot->dq_count) > 1)
423                 goto out_dqlock;
424         mutex_lock(&dqopt->dqio_mutex);
425         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
426                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
427                 /* Write the info */
428                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
429                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
430                                                 dquot->dq_sb, dquot->dq_type);
431                 }
432                 if (ret >= 0)
433                         ret = ret2;
434         }
435         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
436         mutex_unlock(&dqopt->dqio_mutex);
437 out_dqlock:
438         mutex_unlock(&dquot->dq_lock);
439         return ret;
440 }
441 EXPORT_SYMBOL(dquot_release);
442
443 void dquot_destroy(struct dquot *dquot)
444 {
445         kmem_cache_free(dquot_cachep, dquot);
446 }
447 EXPORT_SYMBOL(dquot_destroy);
448
449 static inline void do_destroy_dquot(struct dquot *dquot)
450 {
451         dquot->dq_sb->dq_op->destroy_dquot(dquot);
452 }
453
454 /* Invalidate all dquots on the list. Note that this function is called after
455  * quota is disabled and pointers from inodes removed so there cannot be new
456  * quota users. There can still be some users of quotas due to inodes being
457  * just deleted or pruned by prune_icache() (those are not attached to any
458  * list) or parallel quotactl call. We have to wait for such users.
459  */
460 static void invalidate_dquots(struct super_block *sb, int type)
461 {
462         struct dquot *dquot, *tmp;
463
464 restart:
465         spin_lock(&dq_list_lock);
466         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
467                 if (dquot->dq_sb != sb)
468                         continue;
469                 if (dquot->dq_type != type)
470                         continue;
471                 /* Wait for dquot users */
472                 if (atomic_read(&dquot->dq_count)) {
473                         DEFINE_WAIT(wait);
474
475                         atomic_inc(&dquot->dq_count);
476                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
477                                         TASK_UNINTERRUPTIBLE);
478                         spin_unlock(&dq_list_lock);
479                         /* Once dqput() wakes us up, we know it's time to free
480                          * the dquot.
481                          * IMPORTANT: we rely on the fact that there is always
482                          * at most one process waiting for dquot to free.
483                          * Otherwise dq_count would be > 1 and we would never
484                          * wake up.
485                          */
486                         if (atomic_read(&dquot->dq_count) > 1)
487                                 schedule();
488                         finish_wait(&dquot->dq_wait_unused, &wait);
489                         dqput(dquot);
490                         /* At this moment dquot() need not exist (it could be
491                          * reclaimed by prune_dqcache(). Hence we must
492                          * restart. */
493                         goto restart;
494                 }
495                 /*
496                  * Quota now has no users and it has been written on last
497                  * dqput()
498                  */
499                 remove_dquot_hash(dquot);
500                 remove_free_dquot(dquot);
501                 remove_inuse(dquot);
502                 do_destroy_dquot(dquot);
503         }
504         spin_unlock(&dq_list_lock);
505 }
506
507 /* Call callback for every active dquot on given filesystem */
508 int dquot_scan_active(struct super_block *sb,
509                       int (*fn)(struct dquot *dquot, unsigned long priv),
510                       unsigned long priv)
511 {
512         struct dquot *dquot, *old_dquot = NULL;
513         int ret = 0;
514
515         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
516         spin_lock(&dq_list_lock);
517         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
518                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
519                         continue;
520                 if (dquot->dq_sb != sb)
521                         continue;
522                 /* Now we have active dquot so we can just increase use count */
523                 atomic_inc(&dquot->dq_count);
524                 dqstats.lookups++;
525                 spin_unlock(&dq_list_lock);
526                 dqput(old_dquot);
527                 old_dquot = dquot;
528                 ret = fn(dquot, priv);
529                 if (ret < 0)
530                         goto out;
531                 spin_lock(&dq_list_lock);
532                 /* We are safe to continue now because our dquot could not
533                  * be moved out of the inuse list while we hold the reference */
534         }
535         spin_unlock(&dq_list_lock);
536 out:
537         dqput(old_dquot);
538         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
539         return ret;
540 }
541 EXPORT_SYMBOL(dquot_scan_active);
542
543 int vfs_quota_sync(struct super_block *sb, int type)
544 {
545         struct list_head *dirty;
546         struct dquot *dquot;
547         struct quota_info *dqopt = sb_dqopt(sb);
548         int cnt;
549
550         mutex_lock(&dqopt->dqonoff_mutex);
551         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
552                 if (type != -1 && cnt != type)
553                         continue;
554                 if (!sb_has_quota_active(sb, cnt))
555                         continue;
556                 spin_lock(&dq_list_lock);
557                 dirty = &dqopt->info[cnt].dqi_dirty_list;
558                 while (!list_empty(dirty)) {
559                         dquot = list_first_entry(dirty, struct dquot,
560                                                  dq_dirty);
561                         /* Dirty and inactive can be only bad dquot... */
562                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
563                                 clear_dquot_dirty(dquot);
564                                 continue;
565                         }
566                         /* Now we have active dquot from which someone is
567                          * holding reference so we can safely just increase
568                          * use count */
569                         atomic_inc(&dquot->dq_count);
570                         dqstats.lookups++;
571                         spin_unlock(&dq_list_lock);
572                         sb->dq_op->write_dquot(dquot);
573                         dqput(dquot);
574                         spin_lock(&dq_list_lock);
575                 }
576                 spin_unlock(&dq_list_lock);
577         }
578
579         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
580                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
581                     && info_dirty(&dqopt->info[cnt]))
582                         sb->dq_op->write_info(sb, cnt);
583         spin_lock(&dq_list_lock);
584         dqstats.syncs++;
585         spin_unlock(&dq_list_lock);
586         mutex_unlock(&dqopt->dqonoff_mutex);
587
588         return 0;
589 }
590 EXPORT_SYMBOL(vfs_quota_sync);
591
592 /* Free unused dquots from cache */
593 static void prune_dqcache(int count)
594 {
595         struct list_head *head;
596         struct dquot *dquot;
597
598         head = free_dquots.prev;
599         while (head != &free_dquots && count) {
600                 dquot = list_entry(head, struct dquot, dq_free);
601                 remove_dquot_hash(dquot);
602                 remove_free_dquot(dquot);
603                 remove_inuse(dquot);
604                 do_destroy_dquot(dquot);
605                 count--;
606                 head = free_dquots.prev;
607         }
608 }
609
610 /*
611  * This is called from kswapd when we think we need some
612  * more memory
613  */
614
615 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
616 {
617         if (nr) {
618                 spin_lock(&dq_list_lock);
619                 prune_dqcache(nr);
620                 spin_unlock(&dq_list_lock);
621         }
622         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
623 }
624
625 static struct shrinker dqcache_shrinker = {
626         .shrink = shrink_dqcache_memory,
627         .seeks = DEFAULT_SEEKS,
628 };
629
630 /*
631  * Put reference to dquot
632  * NOTE: If you change this function please check whether dqput_blocks() works right...
633  */
634 void dqput(struct dquot *dquot)
635 {
636         int ret;
637
638         if (!dquot)
639                 return;
640 #ifdef __DQUOT_PARANOIA
641         if (!atomic_read(&dquot->dq_count)) {
642                 printk("VFS: dqput: trying to free free dquot\n");
643                 printk("VFS: device %s, dquot of %s %d\n",
644                         dquot->dq_sb->s_id,
645                         quotatypes[dquot->dq_type],
646                         dquot->dq_id);
647                 BUG();
648         }
649 #endif
650         
651         spin_lock(&dq_list_lock);
652         dqstats.drops++;
653         spin_unlock(&dq_list_lock);
654 we_slept:
655         spin_lock(&dq_list_lock);
656         if (atomic_read(&dquot->dq_count) > 1) {
657                 /* We have more than one user... nothing to do */
658                 atomic_dec(&dquot->dq_count);
659                 /* Releasing dquot during quotaoff phase? */
660                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_type) &&
661                     atomic_read(&dquot->dq_count) == 1)
662                         wake_up(&dquot->dq_wait_unused);
663                 spin_unlock(&dq_list_lock);
664                 return;
665         }
666         /* Need to release dquot? */
667         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
668                 spin_unlock(&dq_list_lock);
669                 /* Commit dquot before releasing */
670                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
671                 if (ret < 0) {
672                         printk(KERN_ERR "VFS: cannot write quota structure on "
673                                 "device %s (error %d). Quota may get out of "
674                                 "sync!\n", dquot->dq_sb->s_id, ret);
675                         /*
676                          * We clear dirty bit anyway, so that we avoid
677                          * infinite loop here
678                          */
679                         spin_lock(&dq_list_lock);
680                         clear_dquot_dirty(dquot);
681                         spin_unlock(&dq_list_lock);
682                 }
683                 goto we_slept;
684         }
685         /* Clear flag in case dquot was inactive (something bad happened) */
686         clear_dquot_dirty(dquot);
687         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
688                 spin_unlock(&dq_list_lock);
689                 dquot->dq_sb->dq_op->release_dquot(dquot);
690                 goto we_slept;
691         }
692         atomic_dec(&dquot->dq_count);
693 #ifdef __DQUOT_PARANOIA
694         /* sanity check */
695         BUG_ON(!list_empty(&dquot->dq_free));
696 #endif
697         put_dquot_last(dquot);
698         spin_unlock(&dq_list_lock);
699 }
700 EXPORT_SYMBOL(dqput);
701
702 struct dquot *dquot_alloc(struct super_block *sb, int type)
703 {
704         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
705 }
706 EXPORT_SYMBOL(dquot_alloc);
707
708 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
709 {
710         struct dquot *dquot;
711
712         dquot = sb->dq_op->alloc_dquot(sb, type);
713         if(!dquot)
714                 return NULL;
715
716         mutex_init(&dquot->dq_lock);
717         INIT_LIST_HEAD(&dquot->dq_free);
718         INIT_LIST_HEAD(&dquot->dq_inuse);
719         INIT_HLIST_NODE(&dquot->dq_hash);
720         INIT_LIST_HEAD(&dquot->dq_dirty);
721         init_waitqueue_head(&dquot->dq_wait_unused);
722         dquot->dq_sb = sb;
723         dquot->dq_type = type;
724         atomic_set(&dquot->dq_count, 1);
725
726         return dquot;
727 }
728
729 /*
730  * Get reference to dquot
731  *
732  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
733  * destroying our dquot by:
734  *   a) checking for quota flags under dq_list_lock and
735  *   b) getting a reference to dquot before we release dq_list_lock
736  */
737 struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
738 {
739         unsigned int hashent = hashfn(sb, id, type);
740         struct dquot *dquot = NULL, *empty = NULL;
741
742         if (!sb_has_quota_active(sb, type))
743                 return NULL;
744 we_slept:
745         spin_lock(&dq_list_lock);
746         spin_lock(&dq_state_lock);
747         if (!sb_has_quota_active(sb, type)) {
748                 spin_unlock(&dq_state_lock);
749                 spin_unlock(&dq_list_lock);
750                 goto out;
751         }
752         spin_unlock(&dq_state_lock);
753
754         dquot = find_dquot(hashent, sb, id, type);
755         if (!dquot) {
756                 if (!empty) {
757                         spin_unlock(&dq_list_lock);
758                         empty = get_empty_dquot(sb, type);
759                         if (!empty)
760                                 schedule();     /* Try to wait for a moment... */
761                         goto we_slept;
762                 }
763                 dquot = empty;
764                 empty = NULL;
765                 dquot->dq_id = id;
766                 /* all dquots go on the inuse_list */
767                 put_inuse(dquot);
768                 /* hash it first so it can be found */
769                 insert_dquot_hash(dquot);
770                 dqstats.lookups++;
771                 spin_unlock(&dq_list_lock);
772         } else {
773                 if (!atomic_read(&dquot->dq_count))
774                         remove_free_dquot(dquot);
775                 atomic_inc(&dquot->dq_count);
776                 dqstats.cache_hits++;
777                 dqstats.lookups++;
778                 spin_unlock(&dq_list_lock);
779         }
780         /* Wait for dq_lock - after this we know that either dquot_release() is
781          * already finished or it will be canceled due to dq_count > 1 test */
782         wait_on_dquot(dquot);
783         /* Read the dquot / allocate space in quota file */
784         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) &&
785             sb->dq_op->acquire_dquot(dquot) < 0) {
786                 dqput(dquot);
787                 dquot = NULL;
788                 goto out;
789         }
790 #ifdef __DQUOT_PARANOIA
791         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
792 #endif
793 out:
794         if (empty)
795                 do_destroy_dquot(empty);
796
797         return dquot;
798 }
799 EXPORT_SYMBOL(dqget);
800
801 static int dqinit_needed(struct inode *inode, int type)
802 {
803         int cnt;
804
805         if (IS_NOQUOTA(inode))
806                 return 0;
807         if (type != -1)
808                 return !inode->i_dquot[type];
809         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
810                 if (!inode->i_dquot[cnt])
811                         return 1;
812         return 0;
813 }
814
815 /* This routine is guarded by dqonoff_mutex mutex */
816 static void add_dquot_ref(struct super_block *sb, int type)
817 {
818         struct inode *inode, *old_inode = NULL;
819
820         spin_lock(&inode_lock);
821         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
822                 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
823                         continue;
824                 if (!atomic_read(&inode->i_writecount))
825                         continue;
826                 if (!dqinit_needed(inode, type))
827                         continue;
828
829                 __iget(inode);
830                 spin_unlock(&inode_lock);
831
832                 iput(old_inode);
833                 sb->dq_op->initialize(inode, type);
834                 /* We hold a reference to 'inode' so it couldn't have been
835                  * removed from s_inodes list while we dropped the inode_lock.
836                  * We cannot iput the inode now as we can be holding the last
837                  * reference and we cannot iput it under inode_lock. So we
838                  * keep the reference and iput it later. */
839                 old_inode = inode;
840                 spin_lock(&inode_lock);
841         }
842         spin_unlock(&inode_lock);
843         iput(old_inode);
844 }
845
846 /*
847  * Return 0 if dqput() won't block.
848  * (note that 1 doesn't necessarily mean blocking)
849  */
850 static inline int dqput_blocks(struct dquot *dquot)
851 {
852         if (atomic_read(&dquot->dq_count) <= 1)
853                 return 1;
854         return 0;
855 }
856
857 /*
858  * Remove references to dquots from inode and add dquot to list for freeing
859  * if we have the last referece to dquot
860  * We can't race with anybody because we hold dqptr_sem for writing...
861  */
862 static int remove_inode_dquot_ref(struct inode *inode, int type,
863                                   struct list_head *tofree_head)
864 {
865         struct dquot *dquot = inode->i_dquot[type];
866
867         inode->i_dquot[type] = NULL;
868         if (dquot) {
869                 if (dqput_blocks(dquot)) {
870 #ifdef __DQUOT_PARANOIA
871                         if (atomic_read(&dquot->dq_count) != 1)
872                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
873 #endif
874                         spin_lock(&dq_list_lock);
875                         /* As dquot must have currently users it can't be on
876                          * the free list... */
877                         list_add(&dquot->dq_free, tofree_head);
878                         spin_unlock(&dq_list_lock);
879                         return 1;
880                 }
881                 else
882                         dqput(dquot);   /* We have guaranteed we won't block */
883         }
884         return 0;
885 }
886
887 /*
888  * Free list of dquots
889  * Dquots are removed from inodes and no new references can be got so we are
890  * the only ones holding reference
891  */
892 static void put_dquot_list(struct list_head *tofree_head)
893 {
894         struct list_head *act_head;
895         struct dquot *dquot;
896
897         act_head = tofree_head->next;
898         while (act_head != tofree_head) {
899                 dquot = list_entry(act_head, struct dquot, dq_free);
900                 act_head = act_head->next;
901                 /* Remove dquot from the list so we won't have problems... */
902                 list_del_init(&dquot->dq_free);
903                 dqput(dquot);
904         }
905 }
906
907 static void remove_dquot_ref(struct super_block *sb, int type,
908                 struct list_head *tofree_head)
909 {
910         struct inode *inode;
911
912         spin_lock(&inode_lock);
913         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
914                 /*
915                  *  We have to scan also I_NEW inodes because they can already
916                  *  have quota pointer initialized. Luckily, we need to touch
917                  *  only quota pointers and these have separate locking
918                  *  (dqptr_sem).
919                  */
920                 if (!IS_NOQUOTA(inode))
921                         remove_inode_dquot_ref(inode, type, tofree_head);
922         }
923         spin_unlock(&inode_lock);
924 }
925
926 /* Gather all references from inodes and drop them */
927 static void drop_dquot_ref(struct super_block *sb, int type)
928 {
929         LIST_HEAD(tofree_head);
930
931         if (sb->dq_op) {
932                 down_write(&sb_dqopt(sb)->dqptr_sem);
933                 remove_dquot_ref(sb, type, &tofree_head);
934                 up_write(&sb_dqopt(sb)->dqptr_sem);
935                 put_dquot_list(&tofree_head);
936         }
937 }
938
939 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
940 {
941         dquot->dq_dqb.dqb_curinodes += number;
942 }
943
944 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
945 {
946         dquot->dq_dqb.dqb_curspace += number;
947 }
948
949 static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
950 {
951         dquot->dq_dqb.dqb_rsvspace += number;
952 }
953
954 /*
955  * Claim reserved quota space
956  */
957 static void dquot_claim_reserved_space(struct dquot *dquot,
958                                                 qsize_t number)
959 {
960         WARN_ON(dquot->dq_dqb.dqb_rsvspace < number);
961         dquot->dq_dqb.dqb_curspace += number;
962         dquot->dq_dqb.dqb_rsvspace -= number;
963 }
964
965 static inline
966 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
967 {
968         dquot->dq_dqb.dqb_rsvspace -= number;
969 }
970
971 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
972 {
973         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
974             dquot->dq_dqb.dqb_curinodes >= number)
975                 dquot->dq_dqb.dqb_curinodes -= number;
976         else
977                 dquot->dq_dqb.dqb_curinodes = 0;
978         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
979                 dquot->dq_dqb.dqb_itime = (time_t) 0;
980         clear_bit(DQ_INODES_B, &dquot->dq_flags);
981 }
982
983 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
984 {
985         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
986             dquot->dq_dqb.dqb_curspace >= number)
987                 dquot->dq_dqb.dqb_curspace -= number;
988         else
989                 dquot->dq_dqb.dqb_curspace = 0;
990         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
991                 dquot->dq_dqb.dqb_btime = (time_t) 0;
992         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
993 }
994
995 static int warning_issued(struct dquot *dquot, const int warntype)
996 {
997         int flag = (warntype == QUOTA_NL_BHARDWARN ||
998                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
999                 ((warntype == QUOTA_NL_IHARDWARN ||
1000                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1001
1002         if (!flag)
1003                 return 0;
1004         return test_and_set_bit(flag, &dquot->dq_flags);
1005 }
1006
1007 #ifdef CONFIG_PRINT_QUOTA_WARNING
1008 static int flag_print_warnings = 1;
1009
1010 static int need_print_warning(struct dquot *dquot)
1011 {
1012         if (!flag_print_warnings)
1013                 return 0;
1014
1015         switch (dquot->dq_type) {
1016                 case USRQUOTA:
1017                         return current_fsuid() == dquot->dq_id;
1018                 case GRPQUOTA:
1019                         return in_group_p(dquot->dq_id);
1020         }
1021         return 0;
1022 }
1023
1024 /* Print warning to user which exceeded quota */
1025 static void print_warning(struct dquot *dquot, const int warntype)
1026 {
1027         char *msg = NULL;
1028         struct tty_struct *tty;
1029
1030         if (warntype == QUOTA_NL_IHARDBELOW ||
1031             warntype == QUOTA_NL_ISOFTBELOW ||
1032             warntype == QUOTA_NL_BHARDBELOW ||
1033             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
1034                 return;
1035
1036         tty = get_current_tty();
1037         if (!tty)
1038                 return;
1039         tty_write_message(tty, dquot->dq_sb->s_id);
1040         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1041                 tty_write_message(tty, ": warning, ");
1042         else
1043                 tty_write_message(tty, ": write failed, ");
1044         tty_write_message(tty, quotatypes[dquot->dq_type]);
1045         switch (warntype) {
1046                 case QUOTA_NL_IHARDWARN:
1047                         msg = " file limit reached.\r\n";
1048                         break;
1049                 case QUOTA_NL_ISOFTLONGWARN:
1050                         msg = " file quota exceeded too long.\r\n";
1051                         break;
1052                 case QUOTA_NL_ISOFTWARN:
1053                         msg = " file quota exceeded.\r\n";
1054                         break;
1055                 case QUOTA_NL_BHARDWARN:
1056                         msg = " block limit reached.\r\n";
1057                         break;
1058                 case QUOTA_NL_BSOFTLONGWARN:
1059                         msg = " block quota exceeded too long.\r\n";
1060                         break;
1061                 case QUOTA_NL_BSOFTWARN:
1062                         msg = " block quota exceeded.\r\n";
1063                         break;
1064         }
1065         tty_write_message(tty, msg);
1066         tty_kref_put(tty);
1067 }
1068 #endif
1069
1070 /*
1071  * Write warnings to the console and send warning messages over netlink.
1072  *
1073  * Note that this function can sleep.
1074  */
1075 static void flush_warnings(struct dquot *const *dquots, char *warntype)
1076 {
1077         struct dquot *dq;
1078         int i;
1079
1080         for (i = 0; i < MAXQUOTAS; i++) {
1081                 dq = dquots[i];
1082                 if (dq && warntype[i] != QUOTA_NL_NOWARN &&
1083                     !warning_issued(dq, warntype[i])) {
1084 #ifdef CONFIG_PRINT_QUOTA_WARNING
1085                         print_warning(dq, warntype[i]);
1086 #endif
1087                         quota_send_warning(dq->dq_type, dq->dq_id,
1088                                            dq->dq_sb->s_dev, warntype[i]);
1089                 }
1090         }
1091 }
1092
1093 static int ignore_hardlimit(struct dquot *dquot)
1094 {
1095         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
1096
1097         return capable(CAP_SYS_RESOURCE) &&
1098                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1099                 !(info->dqi_flags & V1_DQF_RSQUASH));
1100 }
1101
1102 /* needs dq_data_lock */
1103 static int check_idq(struct dquot *dquot, qsize_t inodes, char *warntype)
1104 {
1105         qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1106
1107         *warntype = QUOTA_NL_NOWARN;
1108         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1109             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1110                 return QUOTA_OK;
1111
1112         if (dquot->dq_dqb.dqb_ihardlimit &&
1113             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1114             !ignore_hardlimit(dquot)) {
1115                 *warntype = QUOTA_NL_IHARDWARN;
1116                 return NO_QUOTA;
1117         }
1118
1119         if (dquot->dq_dqb.dqb_isoftlimit &&
1120             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1121             dquot->dq_dqb.dqb_itime &&
1122             get_seconds() >= dquot->dq_dqb.dqb_itime &&
1123             !ignore_hardlimit(dquot)) {
1124                 *warntype = QUOTA_NL_ISOFTLONGWARN;
1125                 return NO_QUOTA;
1126         }
1127
1128         if (dquot->dq_dqb.dqb_isoftlimit &&
1129             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1130             dquot->dq_dqb.dqb_itime == 0) {
1131                 *warntype = QUOTA_NL_ISOFTWARN;
1132                 dquot->dq_dqb.dqb_itime = get_seconds() +
1133                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1134         }
1135
1136         return QUOTA_OK;
1137 }
1138
1139 /* needs dq_data_lock */
1140 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
1141 {
1142         qsize_t tspace;
1143         struct super_block *sb = dquot->dq_sb;
1144
1145         *warntype = QUOTA_NL_NOWARN;
1146         if (!sb_has_quota_limits_enabled(sb, dquot->dq_type) ||
1147             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1148                 return QUOTA_OK;
1149
1150         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1151                 + space;
1152
1153         if (dquot->dq_dqb.dqb_bhardlimit &&
1154             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1155             !ignore_hardlimit(dquot)) {
1156                 if (!prealloc)
1157                         *warntype = QUOTA_NL_BHARDWARN;
1158                 return NO_QUOTA;
1159         }
1160
1161         if (dquot->dq_dqb.dqb_bsoftlimit &&
1162             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1163             dquot->dq_dqb.dqb_btime &&
1164             get_seconds() >= dquot->dq_dqb.dqb_btime &&
1165             !ignore_hardlimit(dquot)) {
1166                 if (!prealloc)
1167                         *warntype = QUOTA_NL_BSOFTLONGWARN;
1168                 return NO_QUOTA;
1169         }
1170
1171         if (dquot->dq_dqb.dqb_bsoftlimit &&
1172             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1173             dquot->dq_dqb.dqb_btime == 0) {
1174                 if (!prealloc) {
1175                         *warntype = QUOTA_NL_BSOFTWARN;
1176                         dquot->dq_dqb.dqb_btime = get_seconds() +
1177                             sb_dqopt(sb)->info[dquot->dq_type].dqi_bgrace;
1178                 }
1179                 else
1180                         /*
1181                          * We don't allow preallocation to exceed softlimit so exceeding will
1182                          * be always printed
1183                          */
1184                         return NO_QUOTA;
1185         }
1186
1187         return QUOTA_OK;
1188 }
1189
1190 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1191 {
1192         qsize_t newinodes;
1193
1194         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1195             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1196             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type))
1197                 return QUOTA_NL_NOWARN;
1198
1199         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1200         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1201                 return QUOTA_NL_ISOFTBELOW;
1202         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1203             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1204                 return QUOTA_NL_IHARDBELOW;
1205         return QUOTA_NL_NOWARN;
1206 }
1207
1208 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1209 {
1210         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1211             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1212                 return QUOTA_NL_NOWARN;
1213
1214         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1215                 return QUOTA_NL_BSOFTBELOW;
1216         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1217             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1218                 return QUOTA_NL_BHARDBELOW;
1219         return QUOTA_NL_NOWARN;
1220 }
1221 /*
1222  *      Initialize quota pointers in inode
1223  *      We do things in a bit complicated way but by that we avoid calling
1224  *      dqget() and thus filesystem callbacks under dqptr_sem.
1225  */
1226 int dquot_initialize(struct inode *inode, int type)
1227 {
1228         unsigned int id = 0;
1229         int cnt, ret = 0;
1230         struct dquot *got[MAXQUOTAS] = { NULL, NULL };
1231         struct super_block *sb = inode->i_sb;
1232
1233         /* First test before acquiring mutex - solves deadlocks when we
1234          * re-enter the quota code and are already holding the mutex */
1235         if (IS_NOQUOTA(inode))
1236                 return 0;
1237
1238         /* First get references to structures we might need. */
1239         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1240                 if (type != -1 && cnt != type)
1241                         continue;
1242                 switch (cnt) {
1243                 case USRQUOTA:
1244                         id = inode->i_uid;
1245                         break;
1246                 case GRPQUOTA:
1247                         id = inode->i_gid;
1248                         break;
1249                 }
1250                 got[cnt] = dqget(sb, id, cnt);
1251         }
1252
1253         down_write(&sb_dqopt(sb)->dqptr_sem);
1254         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
1255         if (IS_NOQUOTA(inode))
1256                 goto out_err;
1257         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1258                 if (type != -1 && cnt != type)
1259                         continue;
1260                 /* Avoid races with quotaoff() */
1261                 if (!sb_has_quota_active(sb, cnt))
1262                         continue;
1263                 if (!inode->i_dquot[cnt]) {
1264                         inode->i_dquot[cnt] = got[cnt];
1265                         got[cnt] = NULL;
1266                 }
1267         }
1268 out_err:
1269         up_write(&sb_dqopt(sb)->dqptr_sem);
1270         /* Drop unused references */
1271         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1272                 dqput(got[cnt]);
1273         return ret;
1274 }
1275 EXPORT_SYMBOL(dquot_initialize);
1276
1277 /*
1278  *      Release all quotas referenced by inode
1279  */
1280 int dquot_drop(struct inode *inode)
1281 {
1282         int cnt;
1283         struct dquot *put[MAXQUOTAS];
1284
1285         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1286         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1287                 put[cnt] = inode->i_dquot[cnt];
1288                 inode->i_dquot[cnt] = NULL;
1289         }
1290         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1291
1292         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1293                 dqput(put[cnt]);
1294         return 0;
1295 }
1296 EXPORT_SYMBOL(dquot_drop);
1297
1298 /* Wrapper to remove references to quota structures from inode */
1299 void vfs_dq_drop(struct inode *inode)
1300 {
1301         /* Here we can get arbitrary inode from clear_inode() so we have
1302          * to be careful. OTOH we don't need locking as quota operations
1303          * are allowed to change only at mount time */
1304         if (!IS_NOQUOTA(inode) && inode->i_sb && inode->i_sb->dq_op
1305             && inode->i_sb->dq_op->drop) {
1306                 int cnt;
1307                 /* Test before calling to rule out calls from proc and such
1308                  * where we are not allowed to block. Note that this is
1309                  * actually reliable test even without the lock - the caller
1310                  * must assure that nobody can come after the DQUOT_DROP and
1311                  * add quota pointers back anyway */
1312                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1313                         if (inode->i_dquot[cnt])
1314                                 break;
1315                 if (cnt < MAXQUOTAS)
1316                         inode->i_sb->dq_op->drop(inode);
1317         }
1318 }
1319 EXPORT_SYMBOL(vfs_dq_drop);
1320
1321 /*
1322  * Following four functions update i_blocks+i_bytes fields and
1323  * quota information (together with appropriate checks)
1324  * NOTE: We absolutely rely on the fact that caller dirties
1325  * the inode (usually macros in quotaops.h care about this) and
1326  * holds a handle for the current transaction so that dquot write and
1327  * inode write go into the same transaction.
1328  */
1329
1330 /*
1331  * This operation can block, but only after everything is updated
1332  */
1333 int __dquot_alloc_space(struct inode *inode, qsize_t number,
1334                         int warn, int reserve)
1335 {
1336         int cnt, ret = QUOTA_OK;
1337         char warntype[MAXQUOTAS];
1338
1339         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1340                 warntype[cnt] = QUOTA_NL_NOWARN;
1341
1342         spin_lock(&dq_data_lock);
1343         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1344                 if (!inode->i_dquot[cnt])
1345                         continue;
1346                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt)
1347                     == NO_QUOTA) {
1348                         ret = NO_QUOTA;
1349                         goto out_unlock;
1350                 }
1351         }
1352         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1353                 if (!inode->i_dquot[cnt])
1354                         continue;
1355                 if (reserve)
1356                         dquot_resv_space(inode->i_dquot[cnt], number);
1357                 else
1358                         dquot_incr_space(inode->i_dquot[cnt], number);
1359         }
1360         if (!reserve)
1361                 inode_add_bytes(inode, number);
1362 out_unlock:
1363         spin_unlock(&dq_data_lock);
1364         flush_warnings(inode->i_dquot, warntype);
1365         return ret;
1366 }
1367
1368 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1369 {
1370         int cnt, ret = QUOTA_OK;
1371
1372         /*
1373          * First test before acquiring mutex - solves deadlocks when we
1374          * re-enter the quota code and are already holding the mutex
1375          */
1376         if (IS_NOQUOTA(inode)) {
1377                 inode_add_bytes(inode, number);
1378                 goto out;
1379         }
1380
1381         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1382         if (IS_NOQUOTA(inode)) {
1383                 inode_add_bytes(inode, number);
1384                 goto out_unlock;
1385         }
1386
1387         ret = __dquot_alloc_space(inode, number, warn, 0);
1388         if (ret == NO_QUOTA)
1389                 goto out_unlock;
1390
1391         /* Dirtify all the dquots - this can block when journalling */
1392         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1393                 if (inode->i_dquot[cnt])
1394                         mark_dquot_dirty(inode->i_dquot[cnt]);
1395 out_unlock:
1396         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1397 out:
1398         return ret;
1399 }
1400 EXPORT_SYMBOL(dquot_alloc_space);
1401
1402 int dquot_reserve_space(struct inode *inode, qsize_t number, int warn)
1403 {
1404         int ret = QUOTA_OK;
1405
1406         if (IS_NOQUOTA(inode))
1407                 goto out;
1408
1409         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1410         if (IS_NOQUOTA(inode))
1411                 goto out_unlock;
1412
1413         ret = __dquot_alloc_space(inode, number, warn, 1);
1414 out_unlock:
1415         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1416 out:
1417         return ret;
1418 }
1419 EXPORT_SYMBOL(dquot_reserve_space);
1420
1421 /*
1422  * This operation can block, but only after everything is updated
1423  */
1424 int dquot_alloc_inode(const struct inode *inode, qsize_t number)
1425 {
1426         int cnt, ret = NO_QUOTA;
1427         char warntype[MAXQUOTAS];
1428
1429         /* First test before acquiring mutex - solves deadlocks when we
1430          * re-enter the quota code and are already holding the mutex */
1431         if (IS_NOQUOTA(inode))
1432                 return QUOTA_OK;
1433         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1434                 warntype[cnt] = QUOTA_NL_NOWARN;
1435         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1436         if (IS_NOQUOTA(inode)) {
1437                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1438                 return QUOTA_OK;
1439         }
1440         spin_lock(&dq_data_lock);
1441         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1442                 if (!inode->i_dquot[cnt])
1443                         continue;
1444                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt)
1445                     == NO_QUOTA)
1446                         goto warn_put_all;
1447         }
1448
1449         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1450                 if (!inode->i_dquot[cnt])
1451                         continue;
1452                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1453         }
1454         ret = QUOTA_OK;
1455 warn_put_all:
1456         spin_unlock(&dq_data_lock);
1457         if (ret == QUOTA_OK)
1458                 /* Dirtify all the dquots - this can block when journalling */
1459                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1460                         if (inode->i_dquot[cnt])
1461                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1462         flush_warnings(inode->i_dquot, warntype);
1463         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1464         return ret;
1465 }
1466 EXPORT_SYMBOL(dquot_alloc_inode);
1467
1468 int dquot_claim_space(struct inode *inode, qsize_t number)
1469 {
1470         int cnt;
1471         int ret = QUOTA_OK;
1472
1473         if (IS_NOQUOTA(inode)) {
1474                 inode_add_bytes(inode, number);
1475                 goto out;
1476         }
1477
1478         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1479         if (IS_NOQUOTA(inode))  {
1480                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1481                 inode_add_bytes(inode, number);
1482                 goto out;
1483         }
1484
1485         spin_lock(&dq_data_lock);
1486         /* Claim reserved quotas to allocated quotas */
1487         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1488                 if (inode->i_dquot[cnt])
1489                         dquot_claim_reserved_space(inode->i_dquot[cnt],
1490                                                         number);
1491         }
1492         /* Update inode bytes */
1493         inode_add_bytes(inode, number);
1494         spin_unlock(&dq_data_lock);
1495         /* Dirtify all the dquots - this can block when journalling */
1496         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1497                 if (inode->i_dquot[cnt])
1498                         mark_dquot_dirty(inode->i_dquot[cnt]);
1499         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1500 out:
1501         return ret;
1502 }
1503 EXPORT_SYMBOL(dquot_claim_space);
1504
1505 /*
1506  * Release reserved quota space
1507  */
1508 void dquot_release_reserved_space(struct inode *inode, qsize_t number)
1509 {
1510         int cnt;
1511
1512         if (IS_NOQUOTA(inode))
1513                 goto out;
1514
1515         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1516         if (IS_NOQUOTA(inode))
1517                 goto out_unlock;
1518
1519         spin_lock(&dq_data_lock);
1520         /* Release reserved dquots */
1521         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1522                 if (inode->i_dquot[cnt])
1523                         dquot_free_reserved_space(inode->i_dquot[cnt], number);
1524         }
1525         spin_unlock(&dq_data_lock);
1526
1527 out_unlock:
1528         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1529 out:
1530         return;
1531 }
1532 EXPORT_SYMBOL(dquot_release_reserved_space);
1533
1534 /*
1535  * This operation can block, but only after everything is updated
1536  */
1537 int dquot_free_space(struct inode *inode, qsize_t number)
1538 {
1539         unsigned int cnt;
1540         char warntype[MAXQUOTAS];
1541
1542         /* First test before acquiring mutex - solves deadlocks when we
1543          * re-enter the quota code and are already holding the mutex */
1544         if (IS_NOQUOTA(inode)) {
1545 out_sub:
1546                 inode_sub_bytes(inode, number);
1547                 return QUOTA_OK;
1548         }
1549
1550         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1551         /* Now recheck reliably when holding dqptr_sem */
1552         if (IS_NOQUOTA(inode)) {
1553                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1554                 goto out_sub;
1555         }
1556         spin_lock(&dq_data_lock);
1557         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1558                 if (!inode->i_dquot[cnt])
1559                         continue;
1560                 warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
1561                 dquot_decr_space(inode->i_dquot[cnt], number);
1562         }
1563         inode_sub_bytes(inode, number);
1564         spin_unlock(&dq_data_lock);
1565         /* Dirtify all the dquots - this can block when journalling */
1566         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1567                 if (inode->i_dquot[cnt])
1568                         mark_dquot_dirty(inode->i_dquot[cnt]);
1569         flush_warnings(inode->i_dquot, warntype);
1570         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1571         return QUOTA_OK;
1572 }
1573 EXPORT_SYMBOL(dquot_free_space);
1574
1575 /*
1576  * This operation can block, but only after everything is updated
1577  */
1578 int dquot_free_inode(const struct inode *inode, qsize_t number)
1579 {
1580         unsigned int cnt;
1581         char warntype[MAXQUOTAS];
1582
1583         /* First test before acquiring mutex - solves deadlocks when we
1584          * re-enter the quota code and are already holding the mutex */
1585         if (IS_NOQUOTA(inode))
1586                 return QUOTA_OK;
1587
1588         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1589         /* Now recheck reliably when holding dqptr_sem */
1590         if (IS_NOQUOTA(inode)) {
1591                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1592                 return QUOTA_OK;
1593         }
1594         spin_lock(&dq_data_lock);
1595         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1596                 if (!inode->i_dquot[cnt])
1597                         continue;
1598                 warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
1599                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1600         }
1601         spin_unlock(&dq_data_lock);
1602         /* Dirtify all the dquots - this can block when journalling */
1603         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1604                 if (inode->i_dquot[cnt])
1605                         mark_dquot_dirty(inode->i_dquot[cnt]);
1606         flush_warnings(inode->i_dquot, warntype);
1607         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1608         return QUOTA_OK;
1609 }
1610 EXPORT_SYMBOL(dquot_free_inode);
1611
1612 /*
1613  * call back function, get reserved quota space from underlying fs
1614  */
1615 qsize_t dquot_get_reserved_space(struct inode *inode)
1616 {
1617         qsize_t reserved_space = 0;
1618
1619         if (sb_any_quota_active(inode->i_sb) &&
1620             inode->i_sb->dq_op->get_reserved_space)
1621                 reserved_space = inode->i_sb->dq_op->get_reserved_space(inode);
1622         return reserved_space;
1623 }
1624
1625 /*
1626  * Transfer the number of inode and blocks from one diskquota to an other.
1627  *
1628  * This operation can block, but only after everything is updated
1629  * A transaction must be started when entering this function.
1630  */
1631 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1632 {
1633         qsize_t space, cur_space;
1634         qsize_t rsv_space = 0;
1635         struct dquot *transfer_from[MAXQUOTAS];
1636         struct dquot *transfer_to[MAXQUOTAS];
1637         int cnt, ret = QUOTA_OK;
1638         int chuid = iattr->ia_valid & ATTR_UID && inode->i_uid != iattr->ia_uid,
1639             chgid = iattr->ia_valid & ATTR_GID && inode->i_gid != iattr->ia_gid;
1640         char warntype_to[MAXQUOTAS];
1641         char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
1642
1643         /* First test before acquiring mutex - solves deadlocks when we
1644          * re-enter the quota code and are already holding the mutex */
1645         if (IS_NOQUOTA(inode))
1646                 return QUOTA_OK;
1647         /* Initialize the arrays */
1648         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1649                 transfer_from[cnt] = NULL;
1650                 transfer_to[cnt] = NULL;
1651                 warntype_to[cnt] = QUOTA_NL_NOWARN;
1652         }
1653         if (chuid)
1654                 transfer_to[USRQUOTA] = dqget(inode->i_sb, iattr->ia_uid,
1655                                               USRQUOTA);
1656         if (chgid)
1657                 transfer_to[GRPQUOTA] = dqget(inode->i_sb, iattr->ia_gid,
1658                                               GRPQUOTA);
1659
1660         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1661         /* Now recheck reliably when holding dqptr_sem */
1662         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1663                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1664                 goto put_all;
1665         }
1666         spin_lock(&dq_data_lock);
1667         cur_space = inode_get_bytes(inode);
1668         rsv_space = dquot_get_reserved_space(inode);
1669         space = cur_space + rsv_space;
1670         /* Build the transfer_from list and check the limits */
1671         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1672                 if (!transfer_to[cnt])
1673                         continue;
1674                 transfer_from[cnt] = inode->i_dquot[cnt];
1675                 if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
1676                     NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
1677                     warntype_to + cnt) == NO_QUOTA)
1678                         goto over_quota;
1679         }
1680
1681         /*
1682          * Finally perform the needed transfer from transfer_from to transfer_to
1683          */
1684         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1685                 /*
1686                  * Skip changes for same uid or gid or for turned off quota-type.
1687                  */
1688                 if (!transfer_to[cnt])
1689                         continue;
1690
1691                 /* Due to IO error we might not have transfer_from[] structure */
1692                 if (transfer_from[cnt]) {
1693                         warntype_from_inodes[cnt] =
1694                                 info_idq_free(transfer_from[cnt], 1);
1695                         warntype_from_space[cnt] =
1696                                 info_bdq_free(transfer_from[cnt], space);
1697                         dquot_decr_inodes(transfer_from[cnt], 1);
1698                         dquot_decr_space(transfer_from[cnt], cur_space);
1699                         dquot_free_reserved_space(transfer_from[cnt],
1700                                                   rsv_space);
1701                 }
1702
1703                 dquot_incr_inodes(transfer_to[cnt], 1);
1704                 dquot_incr_space(transfer_to[cnt], cur_space);
1705                 dquot_resv_space(transfer_to[cnt], rsv_space);
1706
1707                 inode->i_dquot[cnt] = transfer_to[cnt];
1708         }
1709         spin_unlock(&dq_data_lock);
1710         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1711
1712         /* Dirtify all the dquots - this can block when journalling */
1713         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1714                 if (transfer_from[cnt])
1715                         mark_dquot_dirty(transfer_from[cnt]);
1716                 if (transfer_to[cnt]) {
1717                         mark_dquot_dirty(transfer_to[cnt]);
1718                         /* The reference we got is transferred to the inode */
1719                         transfer_to[cnt] = NULL;
1720                 }
1721         }
1722 warn_put_all:
1723         flush_warnings(transfer_to, warntype_to);
1724         flush_warnings(transfer_from, warntype_from_inodes);
1725         flush_warnings(transfer_from, warntype_from_space);
1726 put_all:
1727         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1728                 dqput(transfer_from[cnt]);
1729                 dqput(transfer_to[cnt]);
1730         }
1731         return ret;
1732 over_quota:
1733         spin_unlock(&dq_data_lock);
1734         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1735         /* Clear dquot pointers we don't want to dqput() */
1736         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1737                 transfer_from[cnt] = NULL;
1738         ret = NO_QUOTA;
1739         goto warn_put_all;
1740 }
1741 EXPORT_SYMBOL(dquot_transfer);
1742
1743 /* Wrapper for transferring ownership of an inode */
1744 int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
1745 {
1746         if (sb_any_quota_active(inode->i_sb) && !IS_NOQUOTA(inode)) {
1747                 vfs_dq_init(inode);
1748                 if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
1749                         return 1;
1750         }
1751         return 0;
1752 }
1753 EXPORT_SYMBOL(vfs_dq_transfer);
1754
1755 /*
1756  * Write info of quota file to disk
1757  */
1758 int dquot_commit_info(struct super_block *sb, int type)
1759 {
1760         int ret;
1761         struct quota_info *dqopt = sb_dqopt(sb);
1762
1763         mutex_lock(&dqopt->dqio_mutex);
1764         ret = dqopt->ops[type]->write_file_info(sb, type);
1765         mutex_unlock(&dqopt->dqio_mutex);
1766         return ret;
1767 }
1768 EXPORT_SYMBOL(dquot_commit_info);
1769
1770 /*
1771  * Definitions of diskquota operations.
1772  */
1773 const struct dquot_operations dquot_operations = {
1774         .initialize     = dquot_initialize,
1775         .drop           = dquot_drop,
1776         .alloc_space    = dquot_alloc_space,
1777         .alloc_inode    = dquot_alloc_inode,
1778         .free_space     = dquot_free_space,
1779         .free_inode     = dquot_free_inode,
1780         .transfer       = dquot_transfer,
1781         .write_dquot    = dquot_commit,
1782         .acquire_dquot  = dquot_acquire,
1783         .release_dquot  = dquot_release,
1784         .mark_dirty     = dquot_mark_dquot_dirty,
1785         .write_info     = dquot_commit_info,
1786         .alloc_dquot    = dquot_alloc,
1787         .destroy_dquot  = dquot_destroy,
1788 };
1789
1790 /*
1791  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1792  */
1793 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
1794 {
1795         int cnt, ret = 0;
1796         struct quota_info *dqopt = sb_dqopt(sb);
1797         struct inode *toputinode[MAXQUOTAS];
1798
1799         /* Cannot turn off usage accounting without turning off limits, or
1800          * suspend quotas and simultaneously turn quotas off. */
1801         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
1802             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
1803             DQUOT_USAGE_ENABLED)))
1804                 return -EINVAL;
1805
1806         /* We need to serialize quota_off() for device */
1807         mutex_lock(&dqopt->dqonoff_mutex);
1808
1809         /*
1810          * Skip everything if there's nothing to do. We have to do this because
1811          * sometimes we are called when fill_super() failed and calling
1812          * sync_fs() in such cases does no good.
1813          */
1814         if (!sb_any_quota_loaded(sb)) {
1815                 mutex_unlock(&dqopt->dqonoff_mutex);
1816                 return 0;
1817         }
1818         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1819                 toputinode[cnt] = NULL;
1820                 if (type != -1 && cnt != type)
1821                         continue;
1822                 if (!sb_has_quota_loaded(sb, cnt))
1823                         continue;
1824
1825                 if (flags & DQUOT_SUSPENDED) {
1826                         spin_lock(&dq_state_lock);
1827                         dqopt->flags |=
1828                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
1829                         spin_unlock(&dq_state_lock);
1830                 } else {
1831                         spin_lock(&dq_state_lock);
1832                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
1833                         /* Turning off suspended quotas? */
1834                         if (!sb_has_quota_loaded(sb, cnt) &&
1835                             sb_has_quota_suspended(sb, cnt)) {
1836                                 dqopt->flags &= ~dquot_state_flag(
1837                                                         DQUOT_SUSPENDED, cnt);
1838                                 spin_unlock(&dq_state_lock);
1839                                 iput(dqopt->files[cnt]);
1840                                 dqopt->files[cnt] = NULL;
1841                                 continue;
1842                         }
1843                         spin_unlock(&dq_state_lock);
1844                 }
1845
1846                 /* We still have to keep quota loaded? */
1847                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
1848                         continue;
1849
1850                 /* Note: these are blocking operations */
1851                 drop_dquot_ref(sb, cnt);
1852                 invalidate_dquots(sb, cnt);
1853                 /*
1854                  * Now all dquots should be invalidated, all writes done so we
1855                  * should be only users of the info. No locks needed.
1856                  */
1857                 if (info_dirty(&dqopt->info[cnt]))
1858                         sb->dq_op->write_info(sb, cnt);
1859                 if (dqopt->ops[cnt]->free_file_info)
1860                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1861                 put_quota_format(dqopt->info[cnt].dqi_format);
1862
1863                 toputinode[cnt] = dqopt->files[cnt];
1864                 if (!sb_has_quota_loaded(sb, cnt))
1865                         dqopt->files[cnt] = NULL;
1866                 dqopt->info[cnt].dqi_flags = 0;
1867                 dqopt->info[cnt].dqi_igrace = 0;
1868                 dqopt->info[cnt].dqi_bgrace = 0;
1869                 dqopt->ops[cnt] = NULL;
1870         }
1871         mutex_unlock(&dqopt->dqonoff_mutex);
1872
1873         /* Skip syncing and setting flags if quota files are hidden */
1874         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
1875                 goto put_inodes;
1876
1877         /* Sync the superblock so that buffers with quota data are written to
1878          * disk (and so userspace sees correct data afterwards). */
1879         if (sb->s_op->sync_fs)
1880                 sb->s_op->sync_fs(sb, 1);
1881         sync_blockdev(sb->s_bdev);
1882         /* Now the quota files are just ordinary files and we can set the
1883          * inode flags back. Moreover we discard the pagecache so that
1884          * userspace sees the writes we did bypassing the pagecache. We
1885          * must also discard the blockdev buffers so that we see the
1886          * changes done by userspace on the next quotaon() */
1887         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1888                 if (toputinode[cnt]) {
1889                         mutex_lock(&dqopt->dqonoff_mutex);
1890                         /* If quota was reenabled in the meantime, we have
1891                          * nothing to do */
1892                         if (!sb_has_quota_loaded(sb, cnt)) {
1893                                 mutex_lock_nested(&toputinode[cnt]->i_mutex,
1894                                                   I_MUTEX_QUOTA);
1895                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1896                                   S_NOATIME | S_NOQUOTA);
1897                                 truncate_inode_pages(&toputinode[cnt]->i_data,
1898                                                      0);
1899                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1900                                 mark_inode_dirty(toputinode[cnt]);
1901                         }
1902                         mutex_unlock(&dqopt->dqonoff_mutex);
1903                 }
1904         if (sb->s_bdev)
1905                 invalidate_bdev(sb->s_bdev);
1906 put_inodes:
1907         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1908                 if (toputinode[cnt]) {
1909                         /* On remount RO, we keep the inode pointer so that we
1910                          * can reenable quota on the subsequent remount RW. We
1911                          * have to check 'flags' variable and not use sb_has_
1912                          * function because another quotaon / quotaoff could
1913                          * change global state before we got here. We refuse
1914                          * to suspend quotas when there is pending delete on
1915                          * the quota file... */
1916                         if (!(flags & DQUOT_SUSPENDED))
1917                                 iput(toputinode[cnt]);
1918                         else if (!toputinode[cnt]->i_nlink)
1919                                 ret = -EBUSY;
1920                 }
1921         return ret;
1922 }
1923 EXPORT_SYMBOL(vfs_quota_disable);
1924
1925 int vfs_quota_off(struct super_block *sb, int type, int remount)
1926 {
1927         return vfs_quota_disable(sb, type, remount ? DQUOT_SUSPENDED :
1928                                  (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED));
1929 }
1930 EXPORT_SYMBOL(vfs_quota_off);
1931 /*
1932  *      Turn quotas on on a device
1933  */
1934
1935 /*
1936  * Helper function to turn quotas on when we already have the inode of
1937  * quota file and no quota information is loaded.
1938  */
1939 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
1940         unsigned int flags)
1941 {
1942         struct quota_format_type *fmt = find_quota_format(format_id);
1943         struct super_block *sb = inode->i_sb;
1944         struct quota_info *dqopt = sb_dqopt(sb);
1945         int error;
1946         int oldflags = -1;
1947
1948         if (!fmt)
1949                 return -ESRCH;
1950         if (!S_ISREG(inode->i_mode)) {
1951                 error = -EACCES;
1952                 goto out_fmt;
1953         }
1954         if (IS_RDONLY(inode)) {
1955                 error = -EROFS;
1956                 goto out_fmt;
1957         }
1958         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1959                 error = -EINVAL;
1960                 goto out_fmt;
1961         }
1962         /* Usage always has to be set... */
1963         if (!(flags & DQUOT_USAGE_ENABLED)) {
1964                 error = -EINVAL;
1965                 goto out_fmt;
1966         }
1967
1968         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1969                 /* As we bypass the pagecache we must now flush the inode so
1970                  * that we see all the changes from userspace... */
1971                 write_inode_now(inode, 1);
1972                 /* And now flush the block cache so that kernel sees the
1973                  * changes */
1974                 invalidate_bdev(sb->s_bdev);
1975         }
1976         mutex_lock(&dqopt->dqonoff_mutex);
1977         if (sb_has_quota_loaded(sb, type)) {
1978                 error = -EBUSY;
1979                 goto out_lock;
1980         }
1981
1982         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1983                 /* We don't want quota and atime on quota files (deadlocks
1984                  * possible) Also nobody should write to the file - we use
1985                  * special IO operations which ignore the immutable bit. */
1986                 down_write(&dqopt->dqptr_sem);
1987                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1988                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
1989                                              S_NOQUOTA);
1990                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1991                 mutex_unlock(&inode->i_mutex);
1992                 up_write(&dqopt->dqptr_sem);
1993                 sb->dq_op->drop(inode);
1994         }
1995
1996         error = -EIO;
1997         dqopt->files[type] = igrab(inode);
1998         if (!dqopt->files[type])
1999                 goto out_lock;
2000         error = -EINVAL;
2001         if (!fmt->qf_ops->check_quota_file(sb, type))
2002                 goto out_file_init;
2003
2004         dqopt->ops[type] = fmt->qf_ops;
2005         dqopt->info[type].dqi_format = fmt;
2006         dqopt->info[type].dqi_fmt_id = format_id;
2007         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2008         mutex_lock(&dqopt->dqio_mutex);
2009         error = dqopt->ops[type]->read_file_info(sb, type);
2010         if (error < 0) {
2011                 mutex_unlock(&dqopt->dqio_mutex);
2012                 goto out_file_init;
2013         }
2014         mutex_unlock(&dqopt->dqio_mutex);
2015         spin_lock(&dq_state_lock);
2016         dqopt->flags |= dquot_state_flag(flags, type);
2017         spin_unlock(&dq_state_lock);
2018
2019         add_dquot_ref(sb, type);
2020         mutex_unlock(&dqopt->dqonoff_mutex);
2021
2022         return 0;
2023
2024 out_file_init:
2025         dqopt->files[type] = NULL;
2026         iput(inode);
2027 out_lock:
2028         if (oldflags != -1) {
2029                 down_write(&dqopt->dqptr_sem);
2030                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2031                 /* Set the flags back (in the case of accidental quotaon()
2032                  * on a wrong file we don't want to mess up the flags) */
2033                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
2034                 inode->i_flags |= oldflags;
2035                 mutex_unlock(&inode->i_mutex);
2036                 up_write(&dqopt->dqptr_sem);
2037         }
2038         mutex_unlock(&dqopt->dqonoff_mutex);
2039 out_fmt:
2040         put_quota_format(fmt);
2041
2042         return error; 
2043 }
2044
2045 /* Reenable quotas on remount RW */
2046 static int vfs_quota_on_remount(struct super_block *sb, int type)
2047 {
2048         struct quota_info *dqopt = sb_dqopt(sb);
2049         struct inode *inode;
2050         int ret;
2051         unsigned int flags;
2052
2053         mutex_lock(&dqopt->dqonoff_mutex);
2054         if (!sb_has_quota_suspended(sb, type)) {
2055                 mutex_unlock(&dqopt->dqonoff_mutex);
2056                 return 0;
2057         }
2058         inode = dqopt->files[type];
2059         dqopt->files[type] = NULL;
2060         spin_lock(&dq_state_lock);
2061         flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2062                                                 DQUOT_LIMITS_ENABLED, type);
2063         dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, type);
2064         spin_unlock(&dq_state_lock);
2065         mutex_unlock(&dqopt->dqonoff_mutex);
2066
2067         flags = dquot_generic_flag(flags, type);
2068         ret = vfs_load_quota_inode(inode, type, dqopt->info[type].dqi_fmt_id,
2069                                    flags);
2070         iput(inode);
2071
2072         return ret;
2073 }
2074
2075 int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
2076                       struct path *path)
2077 {
2078         int error = security_quota_on(path->dentry);
2079         if (error)
2080                 return error;
2081         /* Quota file not on the same filesystem? */
2082         if (path->mnt->mnt_sb != sb)
2083                 error = -EXDEV;
2084         else
2085                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
2086                                              format_id, DQUOT_USAGE_ENABLED |
2087                                              DQUOT_LIMITS_ENABLED);
2088         return error;
2089 }
2090 EXPORT_SYMBOL(vfs_quota_on_path);
2091
2092 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
2093                  int remount)
2094 {
2095         struct path path;
2096         int error;
2097
2098         if (remount)
2099                 return vfs_quota_on_remount(sb, type);
2100
2101         error = kern_path(name, LOOKUP_FOLLOW, &path);
2102         if (!error) {
2103                 error = vfs_quota_on_path(sb, type, format_id, &path);
2104                 path_put(&path);
2105         }
2106         return error;
2107 }
2108 EXPORT_SYMBOL(vfs_quota_on);
2109
2110 /*
2111  * More powerful function for turning on quotas allowing setting
2112  * of individual quota flags
2113  */
2114 int vfs_quota_enable(struct inode *inode, int type, int format_id,
2115                 unsigned int flags)
2116 {
2117         int ret = 0;
2118         struct super_block *sb = inode->i_sb;
2119         struct quota_info *dqopt = sb_dqopt(sb);
2120
2121         /* Just unsuspend quotas? */
2122         if (flags & DQUOT_SUSPENDED)
2123                 return vfs_quota_on_remount(sb, type);
2124         if (!flags)
2125                 return 0;
2126         /* Just updating flags needed? */
2127         if (sb_has_quota_loaded(sb, type)) {
2128                 mutex_lock(&dqopt->dqonoff_mutex);
2129                 /* Now do a reliable test... */
2130                 if (!sb_has_quota_loaded(sb, type)) {
2131                         mutex_unlock(&dqopt->dqonoff_mutex);
2132                         goto load_quota;
2133                 }
2134                 if (flags & DQUOT_USAGE_ENABLED &&
2135                     sb_has_quota_usage_enabled(sb, type)) {
2136                         ret = -EBUSY;
2137                         goto out_lock;
2138                 }
2139                 if (flags & DQUOT_LIMITS_ENABLED &&
2140                     sb_has_quota_limits_enabled(sb, type)) {
2141                         ret = -EBUSY;
2142                         goto out_lock;
2143                 }
2144                 spin_lock(&dq_state_lock);
2145                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2146                 spin_unlock(&dq_state_lock);
2147 out_lock:
2148                 mutex_unlock(&dqopt->dqonoff_mutex);
2149                 return ret;
2150         }
2151
2152 load_quota:
2153         return vfs_load_quota_inode(inode, type, format_id, flags);
2154 }
2155 EXPORT_SYMBOL(vfs_quota_enable);
2156
2157 /*
2158  * This function is used when filesystem needs to initialize quotas
2159  * during mount time.
2160  */
2161 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
2162                 int format_id, int type)
2163 {
2164         struct dentry *dentry;
2165         int error;
2166
2167         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2168         if (IS_ERR(dentry))
2169                 return PTR_ERR(dentry);
2170
2171         if (!dentry->d_inode) {
2172                 error = -ENOENT;
2173                 goto out;
2174         }
2175
2176         error = security_quota_on(dentry);
2177         if (!error)
2178                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2179                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2180
2181 out:
2182         dput(dentry);
2183         return error;
2184 }
2185 EXPORT_SYMBOL(vfs_quota_on_mount);
2186
2187 /* Wrapper to turn on quotas when remounting rw */
2188 int vfs_dq_quota_on_remount(struct super_block *sb)
2189 {
2190         int cnt;
2191         int ret = 0, err;
2192
2193         if (!sb->s_qcop || !sb->s_qcop->quota_on)
2194                 return -ENOSYS;
2195         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2196                 err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
2197                 if (err < 0 && !ret)
2198                         ret = err;
2199         }
2200         return ret;
2201 }
2202 EXPORT_SYMBOL(vfs_dq_quota_on_remount);
2203
2204 static inline qsize_t qbtos(qsize_t blocks)
2205 {
2206         return blocks << QIF_DQBLKSIZE_BITS;
2207 }
2208
2209 static inline qsize_t stoqb(qsize_t space)
2210 {
2211         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2212 }
2213
2214 /* Generic routine for getting common part of quota structure */
2215 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
2216 {
2217         struct mem_dqblk *dm = &dquot->dq_dqb;
2218
2219         spin_lock(&dq_data_lock);
2220         di->dqb_bhardlimit = stoqb(dm->dqb_bhardlimit);
2221         di->dqb_bsoftlimit = stoqb(dm->dqb_bsoftlimit);
2222         di->dqb_curspace = dm->dqb_curspace + dm->dqb_rsvspace;
2223         di->dqb_ihardlimit = dm->dqb_ihardlimit;
2224         di->dqb_isoftlimit = dm->dqb_isoftlimit;
2225         di->dqb_curinodes = dm->dqb_curinodes;
2226         di->dqb_btime = dm->dqb_btime;
2227         di->dqb_itime = dm->dqb_itime;
2228         di->dqb_valid = QIF_ALL;
2229         spin_unlock(&dq_data_lock);
2230 }
2231
2232 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id,
2233                   struct if_dqblk *di)
2234 {
2235         struct dquot *dquot;
2236
2237         dquot = dqget(sb, id, type);
2238         if (!dquot)
2239                 return -ESRCH;
2240         do_get_dqblk(dquot, di);
2241         dqput(dquot);
2242
2243         return 0;
2244 }
2245 EXPORT_SYMBOL(vfs_get_dqblk);
2246
2247 /* Generic routine for setting common part of quota structure */
2248 static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
2249 {
2250         struct mem_dqblk *dm = &dquot->dq_dqb;
2251         int check_blim = 0, check_ilim = 0;
2252         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
2253
2254         if ((di->dqb_valid & QIF_BLIMITS &&
2255              (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
2256               di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
2257             (di->dqb_valid & QIF_ILIMITS &&
2258              (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
2259               di->dqb_isoftlimit > dqi->dqi_maxilimit)))
2260                 return -ERANGE;
2261
2262         spin_lock(&dq_data_lock);
2263         if (di->dqb_valid & QIF_SPACE) {
2264                 dm->dqb_curspace = di->dqb_curspace - dm->dqb_rsvspace;
2265                 check_blim = 1;
2266                 __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2267         }
2268         if (di->dqb_valid & QIF_BLIMITS) {
2269                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
2270                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
2271                 check_blim = 1;
2272                 __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2273         }
2274         if (di->dqb_valid & QIF_INODES) {
2275                 dm->dqb_curinodes = di->dqb_curinodes;
2276                 check_ilim = 1;
2277                 __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2278         }
2279         if (di->dqb_valid & QIF_ILIMITS) {
2280                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
2281                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
2282                 check_ilim = 1;
2283                 __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2284         }
2285         if (di->dqb_valid & QIF_BTIME) {
2286                 dm->dqb_btime = di->dqb_btime;
2287                 check_blim = 1;
2288                 __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2289         }
2290         if (di->dqb_valid & QIF_ITIME) {
2291                 dm->dqb_itime = di->dqb_itime;
2292                 check_ilim = 1;
2293                 __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2294         }
2295
2296         if (check_blim) {
2297                 if (!dm->dqb_bsoftlimit ||
2298                     dm->dqb_curspace < dm->dqb_bsoftlimit) {
2299                         dm->dqb_btime = 0;
2300                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2301                 } else if (!(di->dqb_valid & QIF_BTIME))
2302                         /* Set grace only if user hasn't provided his own... */
2303                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2304         }
2305         if (check_ilim) {
2306                 if (!dm->dqb_isoftlimit ||
2307                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2308                         dm->dqb_itime = 0;
2309                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2310                 } else if (!(di->dqb_valid & QIF_ITIME))
2311                         /* Set grace only if user hasn't provided his own... */
2312                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2313         }
2314         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2315             dm->dqb_isoftlimit)
2316                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2317         else
2318                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2319         spin_unlock(&dq_data_lock);
2320         mark_dquot_dirty(dquot);
2321
2322         return 0;
2323 }
2324
2325 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id,
2326                   struct if_dqblk *di)
2327 {
2328         struct dquot *dquot;
2329         int rc;
2330
2331         dquot = dqget(sb, id, type);
2332         if (!dquot) {
2333                 rc = -ESRCH;
2334                 goto out;
2335         }
2336         rc = do_set_dqblk(dquot, di);
2337         dqput(dquot);
2338 out:
2339         return rc;
2340 }
2341 EXPORT_SYMBOL(vfs_set_dqblk);
2342
2343 /* Generic routine for getting common part of quota file information */
2344 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2345 {
2346         struct mem_dqinfo *mi;
2347   
2348         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2349         if (!sb_has_quota_active(sb, type)) {
2350                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2351                 return -ESRCH;
2352         }
2353         mi = sb_dqopt(sb)->info + type;
2354         spin_lock(&dq_data_lock);
2355         ii->dqi_bgrace = mi->dqi_bgrace;
2356         ii->dqi_igrace = mi->dqi_igrace;
2357         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
2358         ii->dqi_valid = IIF_ALL;
2359         spin_unlock(&dq_data_lock);
2360         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2361         return 0;
2362 }
2363 EXPORT_SYMBOL(vfs_get_dqinfo);
2364
2365 /* Generic routine for setting common part of quota file information */
2366 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2367 {
2368         struct mem_dqinfo *mi;
2369         int err = 0;
2370
2371         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2372         if (!sb_has_quota_active(sb, type)) {
2373                 err = -ESRCH;
2374                 goto out;
2375         }
2376         mi = sb_dqopt(sb)->info + type;
2377         spin_lock(&dq_data_lock);
2378         if (ii->dqi_valid & IIF_BGRACE)
2379                 mi->dqi_bgrace = ii->dqi_bgrace;
2380         if (ii->dqi_valid & IIF_IGRACE)
2381                 mi->dqi_igrace = ii->dqi_igrace;
2382         if (ii->dqi_valid & IIF_FLAGS)
2383                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) |
2384                                 (ii->dqi_flags & DQF_MASK);
2385         spin_unlock(&dq_data_lock);
2386         mark_info_dirty(sb, type);
2387         /* Force write to disk */
2388         sb->dq_op->write_info(sb, type);
2389 out:
2390         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2391         return err;
2392 }
2393 EXPORT_SYMBOL(vfs_set_dqinfo);
2394
2395 const struct quotactl_ops vfs_quotactl_ops = {
2396         .quota_on       = vfs_quota_on,
2397         .quota_off      = vfs_quota_off,
2398         .quota_sync     = vfs_quota_sync,
2399         .get_info       = vfs_get_dqinfo,
2400         .set_info       = vfs_set_dqinfo,
2401         .get_dqblk      = vfs_get_dqblk,
2402         .set_dqblk      = vfs_set_dqblk
2403 };
2404
2405 static ctl_table fs_dqstats_table[] = {
2406         {
2407                 .ctl_name       = FS_DQ_LOOKUPS,
2408                 .procname       = "lookups",
2409                 .data           = &dqstats.lookups,
2410                 .maxlen         = sizeof(int),
2411                 .mode           = 0444,
2412                 .proc_handler   = &proc_dointvec,
2413         },
2414         {
2415                 .ctl_name       = FS_DQ_DROPS,
2416                 .procname       = "drops",
2417                 .data           = &dqstats.drops,
2418                 .maxlen         = sizeof(int),
2419                 .mode           = 0444,
2420                 .proc_handler   = &proc_dointvec,
2421         },
2422         {
2423                 .ctl_name       = FS_DQ_READS,
2424                 .procname       = "reads",
2425                 .data           = &dqstats.reads,
2426                 .maxlen         = sizeof(int),
2427                 .mode           = 0444,
2428                 .proc_handler   = &proc_dointvec,
2429         },
2430         {
2431                 .ctl_name       = FS_DQ_WRITES,
2432                 .procname       = "writes",
2433                 .data           = &dqstats.writes,
2434                 .maxlen         = sizeof(int),
2435                 .mode           = 0444,
2436                 .proc_handler   = &proc_dointvec,
2437         },
2438         {
2439                 .ctl_name       = FS_DQ_CACHE_HITS,
2440                 .procname       = "cache_hits",
2441                 .data           = &dqstats.cache_hits,
2442                 .maxlen         = sizeof(int),
2443                 .mode           = 0444,
2444                 .proc_handler   = &proc_dointvec,
2445         },
2446         {
2447                 .ctl_name       = FS_DQ_ALLOCATED,
2448                 .procname       = "allocated_dquots",
2449                 .data           = &dqstats.allocated_dquots,
2450                 .maxlen         = sizeof(int),
2451                 .mode           = 0444,
2452                 .proc_handler   = &proc_dointvec,
2453         },
2454         {
2455                 .ctl_name       = FS_DQ_FREE,
2456                 .procname       = "free_dquots",
2457                 .data           = &dqstats.free_dquots,
2458                 .maxlen         = sizeof(int),
2459                 .mode           = 0444,
2460                 .proc_handler   = &proc_dointvec,
2461         },
2462         {
2463                 .ctl_name       = FS_DQ_SYNCS,
2464                 .procname       = "syncs",
2465                 .data           = &dqstats.syncs,
2466                 .maxlen         = sizeof(int),
2467                 .mode           = 0444,
2468                 .proc_handler   = &proc_dointvec,
2469         },
2470 #ifdef CONFIG_PRINT_QUOTA_WARNING
2471         {
2472                 .ctl_name       = FS_DQ_WARNINGS,
2473                 .procname       = "warnings",
2474                 .data           = &flag_print_warnings,
2475                 .maxlen         = sizeof(int),
2476                 .mode           = 0644,
2477                 .proc_handler   = &proc_dointvec,
2478         },
2479 #endif
2480         { .ctl_name = 0 },
2481 };
2482
2483 static ctl_table fs_table[] = {
2484         {
2485                 .ctl_name       = FS_DQSTATS,
2486                 .procname       = "quota",
2487                 .mode           = 0555,
2488                 .child          = fs_dqstats_table,
2489         },
2490         { .ctl_name = 0 },
2491 };
2492
2493 static ctl_table sys_table[] = {
2494         {
2495                 .ctl_name       = CTL_FS,
2496                 .procname       = "fs",
2497                 .mode           = 0555,
2498                 .child          = fs_table,
2499         },
2500         { .ctl_name = 0 },
2501 };
2502
2503 static int __init dquot_init(void)
2504 {
2505         int i;
2506         unsigned long nr_hash, order;
2507
2508         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2509
2510         register_sysctl_table(sys_table);
2511
2512         dquot_cachep = kmem_cache_create("dquot",
2513                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2514                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2515                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2516                         NULL);
2517
2518         order = 0;
2519         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2520         if (!dquot_hash)
2521                 panic("Cannot create dquot hash table");
2522
2523         /* Find power-of-two hlist_heads which can fit into allocation */
2524         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2525         dq_hash_bits = 0;
2526         do {
2527                 dq_hash_bits++;
2528         } while (nr_hash >> dq_hash_bits);
2529         dq_hash_bits--;
2530
2531         nr_hash = 1UL << dq_hash_bits;
2532         dq_hash_mask = nr_hash - 1;
2533         for (i = 0; i < nr_hash; i++)
2534                 INIT_HLIST_HEAD(dquot_hash + i);
2535
2536         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2537                         nr_hash, order, (PAGE_SIZE << order));
2538
2539         register_shrinker(&dqcache_shrinker);
2540
2541         return 0;
2542 }
2543 module_init(dquot_init);