1cb8fa84300fb76954247e13a1f54b0a9f5e8a17
[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  * inode_reserved_space is managed internally by quota, and protected by
1323  * i_lock similar to i_blocks+i_bytes.
1324  */
1325 static qsize_t *inode_reserved_space(struct inode * inode)
1326 {
1327         /* Filesystem must explicitly define it's own method in order to use
1328          * quota reservation interface */
1329         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1330         return inode->i_sb->dq_op->get_reserved_space(inode);
1331 }
1332
1333 static void inode_add_rsv_space(struct inode *inode, qsize_t number)
1334 {
1335         spin_lock(&inode->i_lock);
1336         *inode_reserved_space(inode) += number;
1337         spin_unlock(&inode->i_lock);
1338 }
1339
1340
1341 static void inode_claim_rsv_space(struct inode *inode, qsize_t number)
1342 {
1343         spin_lock(&inode->i_lock);
1344         *inode_reserved_space(inode) -= number;
1345         __inode_add_bytes(inode, number);
1346         spin_unlock(&inode->i_lock);
1347 }
1348
1349 static void inode_sub_rsv_space(struct inode *inode, qsize_t number)
1350 {
1351         spin_lock(&inode->i_lock);
1352         *inode_reserved_space(inode) -= number;
1353         spin_unlock(&inode->i_lock);
1354 }
1355
1356 static qsize_t inode_get_rsv_space(struct inode *inode)
1357 {
1358         qsize_t ret;
1359         spin_lock(&inode->i_lock);
1360         ret = *inode_reserved_space(inode);
1361         spin_unlock(&inode->i_lock);
1362         return ret;
1363 }
1364
1365 static void inode_incr_space(struct inode *inode, qsize_t number,
1366                                 int reserve)
1367 {
1368         if (reserve)
1369                 inode_add_rsv_space(inode, number);
1370         else
1371                 inode_add_bytes(inode, number);
1372 }
1373
1374 static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
1375 {
1376         if (reserve)
1377                 inode_sub_rsv_space(inode, number);
1378         else
1379                 inode_sub_bytes(inode, number);
1380 }
1381
1382 /*
1383  * Following four functions update i_blocks+i_bytes fields and
1384  * quota information (together with appropriate checks)
1385  * NOTE: We absolutely rely on the fact that caller dirties
1386  * the inode (usually macros in quotaops.h care about this) and
1387  * holds a handle for the current transaction so that dquot write and
1388  * inode write go into the same transaction.
1389  */
1390
1391 /*
1392  * This operation can block, but only after everything is updated
1393  */
1394 int __dquot_alloc_space(struct inode *inode, qsize_t number,
1395                         int warn, int reserve)
1396 {
1397         int cnt, ret = QUOTA_OK;
1398         char warntype[MAXQUOTAS];
1399
1400         /*
1401          * First test before acquiring mutex - solves deadlocks when we
1402          * re-enter the quota code and are already holding the mutex
1403          */
1404         if (IS_NOQUOTA(inode)) {
1405                 inode_incr_space(inode, number, reserve);
1406                 goto out;
1407         }
1408
1409         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1410         if (IS_NOQUOTA(inode)) {
1411                 inode_incr_space(inode, number, reserve);
1412                 goto out_unlock;
1413         }
1414
1415         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1416                 warntype[cnt] = QUOTA_NL_NOWARN;
1417
1418         spin_lock(&dq_data_lock);
1419         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1420                 if (!inode->i_dquot[cnt])
1421                         continue;
1422                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt)
1423                     == NO_QUOTA) {
1424                         ret = NO_QUOTA;
1425                         spin_unlock(&dq_data_lock);
1426                         goto out_flush_warn;
1427                 }
1428         }
1429         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1430                 if (!inode->i_dquot[cnt])
1431                         continue;
1432                 if (reserve)
1433                         dquot_resv_space(inode->i_dquot[cnt], number);
1434                 else
1435                         dquot_incr_space(inode->i_dquot[cnt], number);
1436         }
1437         inode_incr_space(inode, number, reserve);
1438         spin_unlock(&dq_data_lock);
1439
1440         if (reserve)
1441                 goto out_flush_warn;
1442         /* Dirtify all the dquots - this can block when journalling */
1443         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1444                 if (inode->i_dquot[cnt])
1445                         mark_dquot_dirty(inode->i_dquot[cnt]);
1446 out_flush_warn:
1447         flush_warnings(inode->i_dquot, warntype);
1448 out_unlock:
1449         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1450 out:
1451         return ret;
1452 }
1453
1454 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1455 {
1456         return __dquot_alloc_space(inode, number, warn, 0);
1457 }
1458 EXPORT_SYMBOL(dquot_alloc_space);
1459
1460 int dquot_reserve_space(struct inode *inode, qsize_t number, int warn)
1461 {
1462         return __dquot_alloc_space(inode, number, warn, 1);
1463 }
1464 EXPORT_SYMBOL(dquot_reserve_space);
1465
1466 /*
1467  * This operation can block, but only after everything is updated
1468  */
1469 int dquot_alloc_inode(const struct inode *inode, qsize_t number)
1470 {
1471         int cnt, ret = NO_QUOTA;
1472         char warntype[MAXQUOTAS];
1473
1474         /* First test before acquiring mutex - solves deadlocks when we
1475          * re-enter the quota code and are already holding the mutex */
1476         if (IS_NOQUOTA(inode))
1477                 return QUOTA_OK;
1478         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1479                 warntype[cnt] = QUOTA_NL_NOWARN;
1480         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1481         if (IS_NOQUOTA(inode)) {
1482                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1483                 return QUOTA_OK;
1484         }
1485         spin_lock(&dq_data_lock);
1486         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1487                 if (!inode->i_dquot[cnt])
1488                         continue;
1489                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt)
1490                     == NO_QUOTA)
1491                         goto warn_put_all;
1492         }
1493
1494         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1495                 if (!inode->i_dquot[cnt])
1496                         continue;
1497                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1498         }
1499         ret = QUOTA_OK;
1500 warn_put_all:
1501         spin_unlock(&dq_data_lock);
1502         if (ret == QUOTA_OK)
1503                 /* Dirtify all the dquots - this can block when journalling */
1504                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1505                         if (inode->i_dquot[cnt])
1506                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1507         flush_warnings(inode->i_dquot, warntype);
1508         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1509         return ret;
1510 }
1511 EXPORT_SYMBOL(dquot_alloc_inode);
1512
1513 int dquot_claim_space(struct inode *inode, qsize_t number)
1514 {
1515         int cnt;
1516         int ret = QUOTA_OK;
1517
1518         if (IS_NOQUOTA(inode)) {
1519                 inode_claim_rsv_space(inode, number);
1520                 goto out;
1521         }
1522
1523         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1524         if (IS_NOQUOTA(inode))  {
1525                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1526                 inode_claim_rsv_space(inode, number);
1527                 goto out;
1528         }
1529
1530         spin_lock(&dq_data_lock);
1531         /* Claim reserved quotas to allocated quotas */
1532         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1533                 if (inode->i_dquot[cnt])
1534                         dquot_claim_reserved_space(inode->i_dquot[cnt],
1535                                                         number);
1536         }
1537         /* Update inode bytes */
1538         inode_claim_rsv_space(inode, number);
1539         spin_unlock(&dq_data_lock);
1540         /* Dirtify all the dquots - this can block when journalling */
1541         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1542                 if (inode->i_dquot[cnt])
1543                         mark_dquot_dirty(inode->i_dquot[cnt]);
1544         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1545 out:
1546         return ret;
1547 }
1548 EXPORT_SYMBOL(dquot_claim_space);
1549
1550 /*
1551  * This operation can block, but only after everything is updated
1552  */
1553 int __dquot_free_space(struct inode *inode, qsize_t number, int reserve)
1554 {
1555         unsigned int cnt;
1556         char warntype[MAXQUOTAS];
1557
1558         /* First test before acquiring mutex - solves deadlocks when we
1559          * re-enter the quota code and are already holding the mutex */
1560         if (IS_NOQUOTA(inode)) {
1561 out_sub:
1562                 inode_decr_space(inode, number, reserve);
1563                 return QUOTA_OK;
1564         }
1565
1566         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1567         /* Now recheck reliably when holding dqptr_sem */
1568         if (IS_NOQUOTA(inode)) {
1569                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1570                 goto out_sub;
1571         }
1572         spin_lock(&dq_data_lock);
1573         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1574                 if (!inode->i_dquot[cnt])
1575                         continue;
1576                 warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
1577                 if (reserve)
1578                         dquot_free_reserved_space(inode->i_dquot[cnt], number);
1579                 else
1580                         dquot_decr_space(inode->i_dquot[cnt], number);
1581         }
1582         inode_decr_space(inode, number, reserve);
1583         spin_unlock(&dq_data_lock);
1584
1585         if (reserve)
1586                 goto out_unlock;
1587         /* Dirtify all the dquots - this can block when journalling */
1588         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1589                 if (inode->i_dquot[cnt])
1590                         mark_dquot_dirty(inode->i_dquot[cnt]);
1591 out_unlock:
1592         flush_warnings(inode->i_dquot, warntype);
1593         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1594         return QUOTA_OK;
1595 }
1596
1597 int dquot_free_space(struct inode *inode, qsize_t number)
1598 {
1599         return  __dquot_free_space(inode, number, 0);
1600 }
1601 EXPORT_SYMBOL(dquot_free_space);
1602
1603 /*
1604  * Release reserved quota space
1605  */
1606 void dquot_release_reserved_space(struct inode *inode, qsize_t number)
1607 {
1608         __dquot_free_space(inode, number, 1);
1609
1610 }
1611 EXPORT_SYMBOL(dquot_release_reserved_space);
1612
1613 /*
1614  * This operation can block, but only after everything is updated
1615  */
1616 int dquot_free_inode(const struct inode *inode, qsize_t number)
1617 {
1618         unsigned int cnt;
1619         char warntype[MAXQUOTAS];
1620
1621         /* First test before acquiring mutex - solves deadlocks when we
1622          * re-enter the quota code and are already holding the mutex */
1623         if (IS_NOQUOTA(inode))
1624                 return QUOTA_OK;
1625
1626         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1627         /* Now recheck reliably when holding dqptr_sem */
1628         if (IS_NOQUOTA(inode)) {
1629                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1630                 return QUOTA_OK;
1631         }
1632         spin_lock(&dq_data_lock);
1633         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1634                 if (!inode->i_dquot[cnt])
1635                         continue;
1636                 warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
1637                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1638         }
1639         spin_unlock(&dq_data_lock);
1640         /* Dirtify all the dquots - this can block when journalling */
1641         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1642                 if (inode->i_dquot[cnt])
1643                         mark_dquot_dirty(inode->i_dquot[cnt]);
1644         flush_warnings(inode->i_dquot, warntype);
1645         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1646         return QUOTA_OK;
1647 }
1648 EXPORT_SYMBOL(dquot_free_inode);
1649
1650 /*
1651  * Transfer the number of inode and blocks from one diskquota to an other.
1652  *
1653  * This operation can block, but only after everything is updated
1654  * A transaction must be started when entering this function.
1655  */
1656 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1657 {
1658         qsize_t space, cur_space;
1659         qsize_t rsv_space = 0;
1660         struct dquot *transfer_from[MAXQUOTAS];
1661         struct dquot *transfer_to[MAXQUOTAS];
1662         int cnt, ret = QUOTA_OK;
1663         int chuid = iattr->ia_valid & ATTR_UID && inode->i_uid != iattr->ia_uid,
1664             chgid = iattr->ia_valid & ATTR_GID && inode->i_gid != iattr->ia_gid;
1665         char warntype_to[MAXQUOTAS];
1666         char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
1667
1668         /* First test before acquiring mutex - solves deadlocks when we
1669          * re-enter the quota code and are already holding the mutex */
1670         if (IS_NOQUOTA(inode))
1671                 return QUOTA_OK;
1672         /* Initialize the arrays */
1673         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1674                 transfer_from[cnt] = NULL;
1675                 transfer_to[cnt] = NULL;
1676                 warntype_to[cnt] = QUOTA_NL_NOWARN;
1677         }
1678         if (chuid)
1679                 transfer_to[USRQUOTA] = dqget(inode->i_sb, iattr->ia_uid,
1680                                               USRQUOTA);
1681         if (chgid)
1682                 transfer_to[GRPQUOTA] = dqget(inode->i_sb, iattr->ia_gid,
1683                                               GRPQUOTA);
1684
1685         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1686         /* Now recheck reliably when holding dqptr_sem */
1687         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1688                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1689                 goto put_all;
1690         }
1691         spin_lock(&dq_data_lock);
1692         cur_space = inode_get_bytes(inode);
1693         rsv_space = inode_get_rsv_space(inode);
1694         space = cur_space + rsv_space;
1695         /* Build the transfer_from list and check the limits */
1696         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1697                 if (!transfer_to[cnt])
1698                         continue;
1699                 transfer_from[cnt] = inode->i_dquot[cnt];
1700                 if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
1701                     NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
1702                     warntype_to + cnt) == NO_QUOTA)
1703                         goto over_quota;
1704         }
1705
1706         /*
1707          * Finally perform the needed transfer from transfer_from to transfer_to
1708          */
1709         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1710                 /*
1711                  * Skip changes for same uid or gid or for turned off quota-type.
1712                  */
1713                 if (!transfer_to[cnt])
1714                         continue;
1715
1716                 /* Due to IO error we might not have transfer_from[] structure */
1717                 if (transfer_from[cnt]) {
1718                         warntype_from_inodes[cnt] =
1719                                 info_idq_free(transfer_from[cnt], 1);
1720                         warntype_from_space[cnt] =
1721                                 info_bdq_free(transfer_from[cnt], space);
1722                         dquot_decr_inodes(transfer_from[cnt], 1);
1723                         dquot_decr_space(transfer_from[cnt], cur_space);
1724                         dquot_free_reserved_space(transfer_from[cnt],
1725                                                   rsv_space);
1726                 }
1727
1728                 dquot_incr_inodes(transfer_to[cnt], 1);
1729                 dquot_incr_space(transfer_to[cnt], cur_space);
1730                 dquot_resv_space(transfer_to[cnt], rsv_space);
1731
1732                 inode->i_dquot[cnt] = transfer_to[cnt];
1733         }
1734         spin_unlock(&dq_data_lock);
1735         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1736
1737         /* Dirtify all the dquots - this can block when journalling */
1738         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1739                 if (transfer_from[cnt])
1740                         mark_dquot_dirty(transfer_from[cnt]);
1741                 if (transfer_to[cnt]) {
1742                         mark_dquot_dirty(transfer_to[cnt]);
1743                         /* The reference we got is transferred to the inode */
1744                         transfer_to[cnt] = NULL;
1745                 }
1746         }
1747 warn_put_all:
1748         flush_warnings(transfer_to, warntype_to);
1749         flush_warnings(transfer_from, warntype_from_inodes);
1750         flush_warnings(transfer_from, warntype_from_space);
1751 put_all:
1752         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1753                 dqput(transfer_from[cnt]);
1754                 dqput(transfer_to[cnt]);
1755         }
1756         return ret;
1757 over_quota:
1758         spin_unlock(&dq_data_lock);
1759         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1760         /* Clear dquot pointers we don't want to dqput() */
1761         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1762                 transfer_from[cnt] = NULL;
1763         ret = NO_QUOTA;
1764         goto warn_put_all;
1765 }
1766 EXPORT_SYMBOL(dquot_transfer);
1767
1768 /* Wrapper for transferring ownership of an inode */
1769 int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
1770 {
1771         if (sb_any_quota_active(inode->i_sb) && !IS_NOQUOTA(inode)) {
1772                 vfs_dq_init(inode);
1773                 if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
1774                         return 1;
1775         }
1776         return 0;
1777 }
1778 EXPORT_SYMBOL(vfs_dq_transfer);
1779
1780 /*
1781  * Write info of quota file to disk
1782  */
1783 int dquot_commit_info(struct super_block *sb, int type)
1784 {
1785         int ret;
1786         struct quota_info *dqopt = sb_dqopt(sb);
1787
1788         mutex_lock(&dqopt->dqio_mutex);
1789         ret = dqopt->ops[type]->write_file_info(sb, type);
1790         mutex_unlock(&dqopt->dqio_mutex);
1791         return ret;
1792 }
1793 EXPORT_SYMBOL(dquot_commit_info);
1794
1795 /*
1796  * Definitions of diskquota operations.
1797  */
1798 const struct dquot_operations dquot_operations = {
1799         .initialize     = dquot_initialize,
1800         .drop           = dquot_drop,
1801         .alloc_space    = dquot_alloc_space,
1802         .alloc_inode    = dquot_alloc_inode,
1803         .free_space     = dquot_free_space,
1804         .free_inode     = dquot_free_inode,
1805         .transfer       = dquot_transfer,
1806         .write_dquot    = dquot_commit,
1807         .acquire_dquot  = dquot_acquire,
1808         .release_dquot  = dquot_release,
1809         .mark_dirty     = dquot_mark_dquot_dirty,
1810         .write_info     = dquot_commit_info,
1811         .alloc_dquot    = dquot_alloc,
1812         .destroy_dquot  = dquot_destroy,
1813 };
1814
1815 /*
1816  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1817  */
1818 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
1819 {
1820         int cnt, ret = 0;
1821         struct quota_info *dqopt = sb_dqopt(sb);
1822         struct inode *toputinode[MAXQUOTAS];
1823
1824         /* Cannot turn off usage accounting without turning off limits, or
1825          * suspend quotas and simultaneously turn quotas off. */
1826         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
1827             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
1828             DQUOT_USAGE_ENABLED)))
1829                 return -EINVAL;
1830
1831         /* We need to serialize quota_off() for device */
1832         mutex_lock(&dqopt->dqonoff_mutex);
1833
1834         /*
1835          * Skip everything if there's nothing to do. We have to do this because
1836          * sometimes we are called when fill_super() failed and calling
1837          * sync_fs() in such cases does no good.
1838          */
1839         if (!sb_any_quota_loaded(sb)) {
1840                 mutex_unlock(&dqopt->dqonoff_mutex);
1841                 return 0;
1842         }
1843         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1844                 toputinode[cnt] = NULL;
1845                 if (type != -1 && cnt != type)
1846                         continue;
1847                 if (!sb_has_quota_loaded(sb, cnt))
1848                         continue;
1849
1850                 if (flags & DQUOT_SUSPENDED) {
1851                         spin_lock(&dq_state_lock);
1852                         dqopt->flags |=
1853                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
1854                         spin_unlock(&dq_state_lock);
1855                 } else {
1856                         spin_lock(&dq_state_lock);
1857                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
1858                         /* Turning off suspended quotas? */
1859                         if (!sb_has_quota_loaded(sb, cnt) &&
1860                             sb_has_quota_suspended(sb, cnt)) {
1861                                 dqopt->flags &= ~dquot_state_flag(
1862                                                         DQUOT_SUSPENDED, cnt);
1863                                 spin_unlock(&dq_state_lock);
1864                                 iput(dqopt->files[cnt]);
1865                                 dqopt->files[cnt] = NULL;
1866                                 continue;
1867                         }
1868                         spin_unlock(&dq_state_lock);
1869                 }
1870
1871                 /* We still have to keep quota loaded? */
1872                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
1873                         continue;
1874
1875                 /* Note: these are blocking operations */
1876                 drop_dquot_ref(sb, cnt);
1877                 invalidate_dquots(sb, cnt);
1878                 /*
1879                  * Now all dquots should be invalidated, all writes done so we
1880                  * should be only users of the info. No locks needed.
1881                  */
1882                 if (info_dirty(&dqopt->info[cnt]))
1883                         sb->dq_op->write_info(sb, cnt);
1884                 if (dqopt->ops[cnt]->free_file_info)
1885                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1886                 put_quota_format(dqopt->info[cnt].dqi_format);
1887
1888                 toputinode[cnt] = dqopt->files[cnt];
1889                 if (!sb_has_quota_loaded(sb, cnt))
1890                         dqopt->files[cnt] = NULL;
1891                 dqopt->info[cnt].dqi_flags = 0;
1892                 dqopt->info[cnt].dqi_igrace = 0;
1893                 dqopt->info[cnt].dqi_bgrace = 0;
1894                 dqopt->ops[cnt] = NULL;
1895         }
1896         mutex_unlock(&dqopt->dqonoff_mutex);
1897
1898         /* Skip syncing and setting flags if quota files are hidden */
1899         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
1900                 goto put_inodes;
1901
1902         /* Sync the superblock so that buffers with quota data are written to
1903          * disk (and so userspace sees correct data afterwards). */
1904         if (sb->s_op->sync_fs)
1905                 sb->s_op->sync_fs(sb, 1);
1906         sync_blockdev(sb->s_bdev);
1907         /* Now the quota files are just ordinary files and we can set the
1908          * inode flags back. Moreover we discard the pagecache so that
1909          * userspace sees the writes we did bypassing the pagecache. We
1910          * must also discard the blockdev buffers so that we see the
1911          * changes done by userspace on the next quotaon() */
1912         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1913                 if (toputinode[cnt]) {
1914                         mutex_lock(&dqopt->dqonoff_mutex);
1915                         /* If quota was reenabled in the meantime, we have
1916                          * nothing to do */
1917                         if (!sb_has_quota_loaded(sb, cnt)) {
1918                                 mutex_lock_nested(&toputinode[cnt]->i_mutex,
1919                                                   I_MUTEX_QUOTA);
1920                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1921                                   S_NOATIME | S_NOQUOTA);
1922                                 truncate_inode_pages(&toputinode[cnt]->i_data,
1923                                                      0);
1924                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1925                                 mark_inode_dirty(toputinode[cnt]);
1926                         }
1927                         mutex_unlock(&dqopt->dqonoff_mutex);
1928                 }
1929         if (sb->s_bdev)
1930                 invalidate_bdev(sb->s_bdev);
1931 put_inodes:
1932         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1933                 if (toputinode[cnt]) {
1934                         /* On remount RO, we keep the inode pointer so that we
1935                          * can reenable quota on the subsequent remount RW. We
1936                          * have to check 'flags' variable and not use sb_has_
1937                          * function because another quotaon / quotaoff could
1938                          * change global state before we got here. We refuse
1939                          * to suspend quotas when there is pending delete on
1940                          * the quota file... */
1941                         if (!(flags & DQUOT_SUSPENDED))
1942                                 iput(toputinode[cnt]);
1943                         else if (!toputinode[cnt]->i_nlink)
1944                                 ret = -EBUSY;
1945                 }
1946         return ret;
1947 }
1948 EXPORT_SYMBOL(vfs_quota_disable);
1949
1950 int vfs_quota_off(struct super_block *sb, int type, int remount)
1951 {
1952         return vfs_quota_disable(sb, type, remount ? DQUOT_SUSPENDED :
1953                                  (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED));
1954 }
1955 EXPORT_SYMBOL(vfs_quota_off);
1956 /*
1957  *      Turn quotas on on a device
1958  */
1959
1960 /*
1961  * Helper function to turn quotas on when we already have the inode of
1962  * quota file and no quota information is loaded.
1963  */
1964 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
1965         unsigned int flags)
1966 {
1967         struct quota_format_type *fmt = find_quota_format(format_id);
1968         struct super_block *sb = inode->i_sb;
1969         struct quota_info *dqopt = sb_dqopt(sb);
1970         int error;
1971         int oldflags = -1;
1972
1973         if (!fmt)
1974                 return -ESRCH;
1975         if (!S_ISREG(inode->i_mode)) {
1976                 error = -EACCES;
1977                 goto out_fmt;
1978         }
1979         if (IS_RDONLY(inode)) {
1980                 error = -EROFS;
1981                 goto out_fmt;
1982         }
1983         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1984                 error = -EINVAL;
1985                 goto out_fmt;
1986         }
1987         /* Usage always has to be set... */
1988         if (!(flags & DQUOT_USAGE_ENABLED)) {
1989                 error = -EINVAL;
1990                 goto out_fmt;
1991         }
1992
1993         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1994                 /* As we bypass the pagecache we must now flush the inode so
1995                  * that we see all the changes from userspace... */
1996                 write_inode_now(inode, 1);
1997                 /* And now flush the block cache so that kernel sees the
1998                  * changes */
1999                 invalidate_bdev(sb->s_bdev);
2000         }
2001         mutex_lock(&dqopt->dqonoff_mutex);
2002         if (sb_has_quota_loaded(sb, type)) {
2003                 error = -EBUSY;
2004                 goto out_lock;
2005         }
2006
2007         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2008                 /* We don't want quota and atime on quota files (deadlocks
2009                  * possible) Also nobody should write to the file - we use
2010                  * special IO operations which ignore the immutable bit. */
2011                 down_write(&dqopt->dqptr_sem);
2012                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2013                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
2014                                              S_NOQUOTA);
2015                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
2016                 mutex_unlock(&inode->i_mutex);
2017                 up_write(&dqopt->dqptr_sem);
2018                 sb->dq_op->drop(inode);
2019         }
2020
2021         error = -EIO;
2022         dqopt->files[type] = igrab(inode);
2023         if (!dqopt->files[type])
2024                 goto out_lock;
2025         error = -EINVAL;
2026         if (!fmt->qf_ops->check_quota_file(sb, type))
2027                 goto out_file_init;
2028
2029         dqopt->ops[type] = fmt->qf_ops;
2030         dqopt->info[type].dqi_format = fmt;
2031         dqopt->info[type].dqi_fmt_id = format_id;
2032         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2033         mutex_lock(&dqopt->dqio_mutex);
2034         error = dqopt->ops[type]->read_file_info(sb, type);
2035         if (error < 0) {
2036                 mutex_unlock(&dqopt->dqio_mutex);
2037                 goto out_file_init;
2038         }
2039         mutex_unlock(&dqopt->dqio_mutex);
2040         spin_lock(&dq_state_lock);
2041         dqopt->flags |= dquot_state_flag(flags, type);
2042         spin_unlock(&dq_state_lock);
2043
2044         add_dquot_ref(sb, type);
2045         mutex_unlock(&dqopt->dqonoff_mutex);
2046
2047         return 0;
2048
2049 out_file_init:
2050         dqopt->files[type] = NULL;
2051         iput(inode);
2052 out_lock:
2053         if (oldflags != -1) {
2054                 down_write(&dqopt->dqptr_sem);
2055                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2056                 /* Set the flags back (in the case of accidental quotaon()
2057                  * on a wrong file we don't want to mess up the flags) */
2058                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
2059                 inode->i_flags |= oldflags;
2060                 mutex_unlock(&inode->i_mutex);
2061                 up_write(&dqopt->dqptr_sem);
2062         }
2063         mutex_unlock(&dqopt->dqonoff_mutex);
2064 out_fmt:
2065         put_quota_format(fmt);
2066
2067         return error; 
2068 }
2069
2070 /* Reenable quotas on remount RW */
2071 static int vfs_quota_on_remount(struct super_block *sb, int type)
2072 {
2073         struct quota_info *dqopt = sb_dqopt(sb);
2074         struct inode *inode;
2075         int ret;
2076         unsigned int flags;
2077
2078         mutex_lock(&dqopt->dqonoff_mutex);
2079         if (!sb_has_quota_suspended(sb, type)) {
2080                 mutex_unlock(&dqopt->dqonoff_mutex);
2081                 return 0;
2082         }
2083         inode = dqopt->files[type];
2084         dqopt->files[type] = NULL;
2085         spin_lock(&dq_state_lock);
2086         flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2087                                                 DQUOT_LIMITS_ENABLED, type);
2088         dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, type);
2089         spin_unlock(&dq_state_lock);
2090         mutex_unlock(&dqopt->dqonoff_mutex);
2091
2092         flags = dquot_generic_flag(flags, type);
2093         ret = vfs_load_quota_inode(inode, type, dqopt->info[type].dqi_fmt_id,
2094                                    flags);
2095         iput(inode);
2096
2097         return ret;
2098 }
2099
2100 int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
2101                       struct path *path)
2102 {
2103         int error = security_quota_on(path->dentry);
2104         if (error)
2105                 return error;
2106         /* Quota file not on the same filesystem? */
2107         if (path->mnt->mnt_sb != sb)
2108                 error = -EXDEV;
2109         else
2110                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
2111                                              format_id, DQUOT_USAGE_ENABLED |
2112                                              DQUOT_LIMITS_ENABLED);
2113         return error;
2114 }
2115 EXPORT_SYMBOL(vfs_quota_on_path);
2116
2117 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
2118                  int remount)
2119 {
2120         struct path path;
2121         int error;
2122
2123         if (remount)
2124                 return vfs_quota_on_remount(sb, type);
2125
2126         error = kern_path(name, LOOKUP_FOLLOW, &path);
2127         if (!error) {
2128                 error = vfs_quota_on_path(sb, type, format_id, &path);
2129                 path_put(&path);
2130         }
2131         return error;
2132 }
2133 EXPORT_SYMBOL(vfs_quota_on);
2134
2135 /*
2136  * More powerful function for turning on quotas allowing setting
2137  * of individual quota flags
2138  */
2139 int vfs_quota_enable(struct inode *inode, int type, int format_id,
2140                 unsigned int flags)
2141 {
2142         int ret = 0;
2143         struct super_block *sb = inode->i_sb;
2144         struct quota_info *dqopt = sb_dqopt(sb);
2145
2146         /* Just unsuspend quotas? */
2147         if (flags & DQUOT_SUSPENDED)
2148                 return vfs_quota_on_remount(sb, type);
2149         if (!flags)
2150                 return 0;
2151         /* Just updating flags needed? */
2152         if (sb_has_quota_loaded(sb, type)) {
2153                 mutex_lock(&dqopt->dqonoff_mutex);
2154                 /* Now do a reliable test... */
2155                 if (!sb_has_quota_loaded(sb, type)) {
2156                         mutex_unlock(&dqopt->dqonoff_mutex);
2157                         goto load_quota;
2158                 }
2159                 if (flags & DQUOT_USAGE_ENABLED &&
2160                     sb_has_quota_usage_enabled(sb, type)) {
2161                         ret = -EBUSY;
2162                         goto out_lock;
2163                 }
2164                 if (flags & DQUOT_LIMITS_ENABLED &&
2165                     sb_has_quota_limits_enabled(sb, type)) {
2166                         ret = -EBUSY;
2167                         goto out_lock;
2168                 }
2169                 spin_lock(&dq_state_lock);
2170                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2171                 spin_unlock(&dq_state_lock);
2172 out_lock:
2173                 mutex_unlock(&dqopt->dqonoff_mutex);
2174                 return ret;
2175         }
2176
2177 load_quota:
2178         return vfs_load_quota_inode(inode, type, format_id, flags);
2179 }
2180 EXPORT_SYMBOL(vfs_quota_enable);
2181
2182 /*
2183  * This function is used when filesystem needs to initialize quotas
2184  * during mount time.
2185  */
2186 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
2187                 int format_id, int type)
2188 {
2189         struct dentry *dentry;
2190         int error;
2191
2192         mutex_lock(&sb->s_root->d_inode->i_mutex);
2193         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2194         mutex_unlock(&sb->s_root->d_inode->i_mutex);
2195         if (IS_ERR(dentry))
2196                 return PTR_ERR(dentry);
2197
2198         if (!dentry->d_inode) {
2199                 error = -ENOENT;
2200                 goto out;
2201         }
2202
2203         error = security_quota_on(dentry);
2204         if (!error)
2205                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2206                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2207
2208 out:
2209         dput(dentry);
2210         return error;
2211 }
2212 EXPORT_SYMBOL(vfs_quota_on_mount);
2213
2214 /* Wrapper to turn on quotas when remounting rw */
2215 int vfs_dq_quota_on_remount(struct super_block *sb)
2216 {
2217         int cnt;
2218         int ret = 0, err;
2219
2220         if (!sb->s_qcop || !sb->s_qcop->quota_on)
2221                 return -ENOSYS;
2222         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2223                 err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
2224                 if (err < 0 && !ret)
2225                         ret = err;
2226         }
2227         return ret;
2228 }
2229 EXPORT_SYMBOL(vfs_dq_quota_on_remount);
2230
2231 static inline qsize_t qbtos(qsize_t blocks)
2232 {
2233         return blocks << QIF_DQBLKSIZE_BITS;
2234 }
2235
2236 static inline qsize_t stoqb(qsize_t space)
2237 {
2238         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2239 }
2240
2241 /* Generic routine for getting common part of quota structure */
2242 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
2243 {
2244         struct mem_dqblk *dm = &dquot->dq_dqb;
2245
2246         spin_lock(&dq_data_lock);
2247         di->dqb_bhardlimit = stoqb(dm->dqb_bhardlimit);
2248         di->dqb_bsoftlimit = stoqb(dm->dqb_bsoftlimit);
2249         di->dqb_curspace = dm->dqb_curspace + dm->dqb_rsvspace;
2250         di->dqb_ihardlimit = dm->dqb_ihardlimit;
2251         di->dqb_isoftlimit = dm->dqb_isoftlimit;
2252         di->dqb_curinodes = dm->dqb_curinodes;
2253         di->dqb_btime = dm->dqb_btime;
2254         di->dqb_itime = dm->dqb_itime;
2255         di->dqb_valid = QIF_ALL;
2256         spin_unlock(&dq_data_lock);
2257 }
2258
2259 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id,
2260                   struct if_dqblk *di)
2261 {
2262         struct dquot *dquot;
2263
2264         dquot = dqget(sb, id, type);
2265         if (!dquot)
2266                 return -ESRCH;
2267         do_get_dqblk(dquot, di);
2268         dqput(dquot);
2269
2270         return 0;
2271 }
2272 EXPORT_SYMBOL(vfs_get_dqblk);
2273
2274 /* Generic routine for setting common part of quota structure */
2275 static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
2276 {
2277         struct mem_dqblk *dm = &dquot->dq_dqb;
2278         int check_blim = 0, check_ilim = 0;
2279         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
2280
2281         if ((di->dqb_valid & QIF_BLIMITS &&
2282              (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
2283               di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
2284             (di->dqb_valid & QIF_ILIMITS &&
2285              (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
2286               di->dqb_isoftlimit > dqi->dqi_maxilimit)))
2287                 return -ERANGE;
2288
2289         spin_lock(&dq_data_lock);
2290         if (di->dqb_valid & QIF_SPACE) {
2291                 dm->dqb_curspace = di->dqb_curspace - dm->dqb_rsvspace;
2292                 check_blim = 1;
2293                 __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2294         }
2295         if (di->dqb_valid & QIF_BLIMITS) {
2296                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
2297                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
2298                 check_blim = 1;
2299                 __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2300         }
2301         if (di->dqb_valid & QIF_INODES) {
2302                 dm->dqb_curinodes = di->dqb_curinodes;
2303                 check_ilim = 1;
2304                 __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2305         }
2306         if (di->dqb_valid & QIF_ILIMITS) {
2307                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
2308                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
2309                 check_ilim = 1;
2310                 __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2311         }
2312         if (di->dqb_valid & QIF_BTIME) {
2313                 dm->dqb_btime = di->dqb_btime;
2314                 check_blim = 1;
2315                 __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2316         }
2317         if (di->dqb_valid & QIF_ITIME) {
2318                 dm->dqb_itime = di->dqb_itime;
2319                 check_ilim = 1;
2320                 __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2321         }
2322
2323         if (check_blim) {
2324                 if (!dm->dqb_bsoftlimit ||
2325                     dm->dqb_curspace < dm->dqb_bsoftlimit) {
2326                         dm->dqb_btime = 0;
2327                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2328                 } else if (!(di->dqb_valid & QIF_BTIME))
2329                         /* Set grace only if user hasn't provided his own... */
2330                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2331         }
2332         if (check_ilim) {
2333                 if (!dm->dqb_isoftlimit ||
2334                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2335                         dm->dqb_itime = 0;
2336                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2337                 } else if (!(di->dqb_valid & QIF_ITIME))
2338                         /* Set grace only if user hasn't provided his own... */
2339                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2340         }
2341         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2342             dm->dqb_isoftlimit)
2343                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2344         else
2345                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2346         spin_unlock(&dq_data_lock);
2347         mark_dquot_dirty(dquot);
2348
2349         return 0;
2350 }
2351
2352 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id,
2353                   struct if_dqblk *di)
2354 {
2355         struct dquot *dquot;
2356         int rc;
2357
2358         dquot = dqget(sb, id, type);
2359         if (!dquot) {
2360                 rc = -ESRCH;
2361                 goto out;
2362         }
2363         rc = do_set_dqblk(dquot, di);
2364         dqput(dquot);
2365 out:
2366         return rc;
2367 }
2368 EXPORT_SYMBOL(vfs_set_dqblk);
2369
2370 /* Generic routine for getting common part of quota file information */
2371 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2372 {
2373         struct mem_dqinfo *mi;
2374   
2375         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2376         if (!sb_has_quota_active(sb, type)) {
2377                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2378                 return -ESRCH;
2379         }
2380         mi = sb_dqopt(sb)->info + type;
2381         spin_lock(&dq_data_lock);
2382         ii->dqi_bgrace = mi->dqi_bgrace;
2383         ii->dqi_igrace = mi->dqi_igrace;
2384         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
2385         ii->dqi_valid = IIF_ALL;
2386         spin_unlock(&dq_data_lock);
2387         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2388         return 0;
2389 }
2390 EXPORT_SYMBOL(vfs_get_dqinfo);
2391
2392 /* Generic routine for setting common part of quota file information */
2393 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2394 {
2395         struct mem_dqinfo *mi;
2396         int err = 0;
2397
2398         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2399         if (!sb_has_quota_active(sb, type)) {
2400                 err = -ESRCH;
2401                 goto out;
2402         }
2403         mi = sb_dqopt(sb)->info + type;
2404         spin_lock(&dq_data_lock);
2405         if (ii->dqi_valid & IIF_BGRACE)
2406                 mi->dqi_bgrace = ii->dqi_bgrace;
2407         if (ii->dqi_valid & IIF_IGRACE)
2408                 mi->dqi_igrace = ii->dqi_igrace;
2409         if (ii->dqi_valid & IIF_FLAGS)
2410                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) |
2411                                 (ii->dqi_flags & DQF_MASK);
2412         spin_unlock(&dq_data_lock);
2413         mark_info_dirty(sb, type);
2414         /* Force write to disk */
2415         sb->dq_op->write_info(sb, type);
2416 out:
2417         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2418         return err;
2419 }
2420 EXPORT_SYMBOL(vfs_set_dqinfo);
2421
2422 const struct quotactl_ops vfs_quotactl_ops = {
2423         .quota_on       = vfs_quota_on,
2424         .quota_off      = vfs_quota_off,
2425         .quota_sync     = vfs_quota_sync,
2426         .get_info       = vfs_get_dqinfo,
2427         .set_info       = vfs_set_dqinfo,
2428         .get_dqblk      = vfs_get_dqblk,
2429         .set_dqblk      = vfs_set_dqblk
2430 };
2431
2432 static ctl_table fs_dqstats_table[] = {
2433         {
2434                 .procname       = "lookups",
2435                 .data           = &dqstats.lookups,
2436                 .maxlen         = sizeof(int),
2437                 .mode           = 0444,
2438                 .proc_handler   = proc_dointvec,
2439         },
2440         {
2441                 .procname       = "drops",
2442                 .data           = &dqstats.drops,
2443                 .maxlen         = sizeof(int),
2444                 .mode           = 0444,
2445                 .proc_handler   = proc_dointvec,
2446         },
2447         {
2448                 .procname       = "reads",
2449                 .data           = &dqstats.reads,
2450                 .maxlen         = sizeof(int),
2451                 .mode           = 0444,
2452                 .proc_handler   = proc_dointvec,
2453         },
2454         {
2455                 .procname       = "writes",
2456                 .data           = &dqstats.writes,
2457                 .maxlen         = sizeof(int),
2458                 .mode           = 0444,
2459                 .proc_handler   = proc_dointvec,
2460         },
2461         {
2462                 .procname       = "cache_hits",
2463                 .data           = &dqstats.cache_hits,
2464                 .maxlen         = sizeof(int),
2465                 .mode           = 0444,
2466                 .proc_handler   = proc_dointvec,
2467         },
2468         {
2469                 .procname       = "allocated_dquots",
2470                 .data           = &dqstats.allocated_dquots,
2471                 .maxlen         = sizeof(int),
2472                 .mode           = 0444,
2473                 .proc_handler   = proc_dointvec,
2474         },
2475         {
2476                 .procname       = "free_dquots",
2477                 .data           = &dqstats.free_dquots,
2478                 .maxlen         = sizeof(int),
2479                 .mode           = 0444,
2480                 .proc_handler   = proc_dointvec,
2481         },
2482         {
2483                 .procname       = "syncs",
2484                 .data           = &dqstats.syncs,
2485                 .maxlen         = sizeof(int),
2486                 .mode           = 0444,
2487                 .proc_handler   = proc_dointvec,
2488         },
2489 #ifdef CONFIG_PRINT_QUOTA_WARNING
2490         {
2491                 .procname       = "warnings",
2492                 .data           = &flag_print_warnings,
2493                 .maxlen         = sizeof(int),
2494                 .mode           = 0644,
2495                 .proc_handler   = proc_dointvec,
2496         },
2497 #endif
2498         { },
2499 };
2500
2501 static ctl_table fs_table[] = {
2502         {
2503                 .procname       = "quota",
2504                 .mode           = 0555,
2505                 .child          = fs_dqstats_table,
2506         },
2507         { },
2508 };
2509
2510 static ctl_table sys_table[] = {
2511         {
2512                 .procname       = "fs",
2513                 .mode           = 0555,
2514                 .child          = fs_table,
2515         },
2516         { },
2517 };
2518
2519 static int __init dquot_init(void)
2520 {
2521         int i;
2522         unsigned long nr_hash, order;
2523
2524         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2525
2526         register_sysctl_table(sys_table);
2527
2528         dquot_cachep = kmem_cache_create("dquot",
2529                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2530                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2531                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2532                         NULL);
2533
2534         order = 0;
2535         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2536         if (!dquot_hash)
2537                 panic("Cannot create dquot hash table");
2538
2539         /* Find power-of-two hlist_heads which can fit into allocation */
2540         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2541         dq_hash_bits = 0;
2542         do {
2543                 dq_hash_bits++;
2544         } while (nr_hash >> dq_hash_bits);
2545         dq_hash_bits--;
2546
2547         nr_hash = 1UL << dq_hash_bits;
2548         dq_hash_mask = nr_hash - 1;
2549         for (i = 0; i < nr_hash; i++)
2550                 INIT_HLIST_HEAD(dquot_hash + i);
2551
2552         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2553                         nr_hash, order, (PAGE_SIZE << order));
2554
2555         register_shrinker(&dqcache_shrinker);
2556
2557         return 0;
2558 }
2559 module_init(dquot_init);