quota: sb_quota state flags cleanup
[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  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
105  * inode is a quota file). Functions adding pointers from inode to dquots have
106  * to check this flag under dqptr_sem and then (if S_NOQUOTA is not set) they
107  * have to do all pointer modifications before dropping dqptr_sem. This makes
108  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
109  * then drops all pointers to dquots from an inode.
110  *
111  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
112  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
113  * Currently dquot is locked only when it is being read to memory (or space for
114  * it is being allocated) on the first dqget() and when it is being released on
115  * the last dqput(). The allocation and release oparations are serialized by
116  * the dq_lock and by checking the use count in dquot_release().  Write
117  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
118  * spinlock to internal buffers before writing.
119  *
120  * Lock ordering (including related VFS locks) is the following:
121  *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
122  *   dqio_mutex
123  * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
124  * dqptr_sem. But filesystem has to count with the fact that functions such as
125  * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
126  * from inside a transaction to keep filesystem consistency after a crash. Also
127  * filesystems usually want to do some IO on dquot from ->mark_dirty which is
128  * called with dqptr_sem held.
129  * i_mutex on quota files is special (it's below dqio_mutex)
130  */
131
132 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
133 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
134 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
135 EXPORT_SYMBOL(dq_data_lock);
136
137 static char *quotatypes[] = INITQFNAMES;
138 static struct quota_format_type *quota_formats; /* List of registered formats */
139 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
140
141 /* SLAB cache for dquot structures */
142 static struct kmem_cache *dquot_cachep;
143
144 int register_quota_format(struct quota_format_type *fmt)
145 {
146         spin_lock(&dq_list_lock);
147         fmt->qf_next = quota_formats;
148         quota_formats = fmt;
149         spin_unlock(&dq_list_lock);
150         return 0;
151 }
152 EXPORT_SYMBOL(register_quota_format);
153
154 void unregister_quota_format(struct quota_format_type *fmt)
155 {
156         struct quota_format_type **actqf;
157
158         spin_lock(&dq_list_lock);
159         for (actqf = &quota_formats; *actqf && *actqf != fmt;
160              actqf = &(*actqf)->qf_next)
161                 ;
162         if (*actqf)
163                 *actqf = (*actqf)->qf_next;
164         spin_unlock(&dq_list_lock);
165 }
166 EXPORT_SYMBOL(unregister_quota_format);
167
168 static struct quota_format_type *find_quota_format(int id)
169 {
170         struct quota_format_type *actqf;
171
172         spin_lock(&dq_list_lock);
173         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
174              actqf = actqf->qf_next)
175                 ;
176         if (!actqf || !try_module_get(actqf->qf_owner)) {
177                 int qm;
178
179                 spin_unlock(&dq_list_lock);
180                 
181                 for (qm = 0; module_names[qm].qm_fmt_id &&
182                              module_names[qm].qm_fmt_id != id; qm++)
183                         ;
184                 if (!module_names[qm].qm_fmt_id ||
185                     request_module(module_names[qm].qm_mod_name))
186                         return NULL;
187
188                 spin_lock(&dq_list_lock);
189                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
190                      actqf = actqf->qf_next)
191                         ;
192                 if (actqf && !try_module_get(actqf->qf_owner))
193                         actqf = NULL;
194         }
195         spin_unlock(&dq_list_lock);
196         return actqf;
197 }
198
199 static void put_quota_format(struct quota_format_type *fmt)
200 {
201         module_put(fmt->qf_owner);
202 }
203
204 /*
205  * Dquot List Management:
206  * The quota code uses three lists for dquot management: the inuse_list,
207  * free_dquots, and dquot_hash[] array. A single dquot structure may be
208  * on all three lists, depending on its current state.
209  *
210  * All dquots are placed to the end of inuse_list when first created, and this
211  * list is used for invalidate operation, which must look at every dquot.
212  *
213  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
214  * and this list is searched whenever we need an available dquot.  Dquots are
215  * removed from the list as soon as they are used again, and
216  * dqstats.free_dquots gives the number of dquots on the list. When
217  * dquot is invalidated it's completely released from memory.
218  *
219  * Dquots with a specific identity (device, type and id) are placed on
220  * one of the dquot_hash[] hash chains. The provides an efficient search
221  * mechanism to locate a specific dquot.
222  */
223
224 static LIST_HEAD(inuse_list);
225 static LIST_HEAD(free_dquots);
226 static unsigned int dq_hash_bits, dq_hash_mask;
227 static struct hlist_head *dquot_hash;
228
229 struct dqstats dqstats;
230 EXPORT_SYMBOL(dqstats);
231
232 static qsize_t inode_get_rsv_space(struct inode *inode);
233
234 static inline unsigned int
235 hashfn(const struct super_block *sb, unsigned int id, int type)
236 {
237         unsigned long tmp;
238
239         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
240         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
241 }
242
243 /*
244  * Following list functions expect dq_list_lock to be held
245  */
246 static inline void insert_dquot_hash(struct dquot *dquot)
247 {
248         struct hlist_head *head;
249         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
250         hlist_add_head(&dquot->dq_hash, head);
251 }
252
253 static inline void remove_dquot_hash(struct dquot *dquot)
254 {
255         hlist_del_init(&dquot->dq_hash);
256 }
257
258 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
259                                 unsigned int id, int type)
260 {
261         struct hlist_node *node;
262         struct dquot *dquot;
263
264         hlist_for_each (node, dquot_hash+hashent) {
265                 dquot = hlist_entry(node, struct dquot, dq_hash);
266                 if (dquot->dq_sb == sb && dquot->dq_id == id &&
267                     dquot->dq_type == type)
268                         return dquot;
269         }
270         return NULL;
271 }
272
273 /* Add a dquot to the tail of the free list */
274 static inline void put_dquot_last(struct dquot *dquot)
275 {
276         list_add_tail(&dquot->dq_free, &free_dquots);
277         dqstats.free_dquots++;
278 }
279
280 static inline void remove_free_dquot(struct dquot *dquot)
281 {
282         if (list_empty(&dquot->dq_free))
283                 return;
284         list_del_init(&dquot->dq_free);
285         dqstats.free_dquots--;
286 }
287
288 static inline void put_inuse(struct dquot *dquot)
289 {
290         /* We add to the back of inuse list so we don't have to restart
291          * when traversing this list and we block */
292         list_add_tail(&dquot->dq_inuse, &inuse_list);
293         dqstats.allocated_dquots++;
294 }
295
296 static inline void remove_inuse(struct dquot *dquot)
297 {
298         dqstats.allocated_dquots--;
299         list_del(&dquot->dq_inuse);
300 }
301 /*
302  * End of list functions needing dq_list_lock
303  */
304
305 static void wait_on_dquot(struct dquot *dquot)
306 {
307         mutex_lock(&dquot->dq_lock);
308         mutex_unlock(&dquot->dq_lock);
309 }
310
311 static inline int dquot_dirty(struct dquot *dquot)
312 {
313         return test_bit(DQ_MOD_B, &dquot->dq_flags);
314 }
315
316 static inline int mark_dquot_dirty(struct dquot *dquot)
317 {
318         return dquot->dq_sb->dq_op->mark_dirty(dquot);
319 }
320
321 int dquot_mark_dquot_dirty(struct dquot *dquot)
322 {
323         spin_lock(&dq_list_lock);
324         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
325                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
326                                 info[dquot->dq_type].dqi_dirty_list);
327         spin_unlock(&dq_list_lock);
328         return 0;
329 }
330 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
331
332 /* Dirtify all the dquots - this can block when journalling */
333 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
334 {
335         int ret, err, cnt;
336
337         ret = err = 0;
338         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
339                 if (dquot[cnt])
340                         /* Even in case of error we have to continue */
341                         ret = mark_dquot_dirty(dquot[cnt]);
342                 if (!err)
343                         err = ret;
344         }
345         return err;
346 }
347
348 static inline void dqput_all(struct dquot **dquot)
349 {
350         unsigned int cnt;
351
352         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
353                 dqput(dquot[cnt]);
354 }
355
356 /* This function needs dq_list_lock */
357 static inline int clear_dquot_dirty(struct dquot *dquot)
358 {
359         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
360                 return 0;
361         list_del_init(&dquot->dq_dirty);
362         return 1;
363 }
364
365 void mark_info_dirty(struct super_block *sb, int type)
366 {
367         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
368 }
369 EXPORT_SYMBOL(mark_info_dirty);
370
371 /*
372  *      Read dquot from disk and alloc space for it
373  */
374
375 int dquot_acquire(struct dquot *dquot)
376 {
377         int ret = 0, ret2 = 0;
378         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
379
380         mutex_lock(&dquot->dq_lock);
381         mutex_lock(&dqopt->dqio_mutex);
382         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
383                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
384         if (ret < 0)
385                 goto out_iolock;
386         set_bit(DQ_READ_B, &dquot->dq_flags);
387         /* Instantiate dquot if needed */
388         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
389                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
390                 /* Write the info if needed */
391                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
392                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
393                                                 dquot->dq_sb, dquot->dq_type);
394                 }
395                 if (ret < 0)
396                         goto out_iolock;
397                 if (ret2 < 0) {
398                         ret = ret2;
399                         goto out_iolock;
400                 }
401         }
402         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
403 out_iolock:
404         mutex_unlock(&dqopt->dqio_mutex);
405         mutex_unlock(&dquot->dq_lock);
406         return ret;
407 }
408 EXPORT_SYMBOL(dquot_acquire);
409
410 /*
411  *      Write dquot to disk
412  */
413 int dquot_commit(struct dquot *dquot)
414 {
415         int ret = 0, ret2 = 0;
416         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
417
418         mutex_lock(&dqopt->dqio_mutex);
419         spin_lock(&dq_list_lock);
420         if (!clear_dquot_dirty(dquot)) {
421                 spin_unlock(&dq_list_lock);
422                 goto out_sem;
423         }
424         spin_unlock(&dq_list_lock);
425         /* Inactive dquot can be only if there was error during read/init
426          * => we have better not writing it */
427         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
428                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
429                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
430                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
431                                                 dquot->dq_sb, dquot->dq_type);
432                 }
433                 if (ret >= 0)
434                         ret = ret2;
435         }
436 out_sem:
437         mutex_unlock(&dqopt->dqio_mutex);
438         return ret;
439 }
440 EXPORT_SYMBOL(dquot_commit);
441
442 /*
443  *      Release dquot
444  */
445 int dquot_release(struct dquot *dquot)
446 {
447         int ret = 0, ret2 = 0;
448         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
449
450         mutex_lock(&dquot->dq_lock);
451         /* Check whether we are not racing with some other dqget() */
452         if (atomic_read(&dquot->dq_count) > 1)
453                 goto out_dqlock;
454         mutex_lock(&dqopt->dqio_mutex);
455         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
456                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
457                 /* Write the info */
458                 if (info_dirty(&dqopt->info[dquot->dq_type])) {
459                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(
460                                                 dquot->dq_sb, dquot->dq_type);
461                 }
462                 if (ret >= 0)
463                         ret = ret2;
464         }
465         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
466         mutex_unlock(&dqopt->dqio_mutex);
467 out_dqlock:
468         mutex_unlock(&dquot->dq_lock);
469         return ret;
470 }
471 EXPORT_SYMBOL(dquot_release);
472
473 void dquot_destroy(struct dquot *dquot)
474 {
475         kmem_cache_free(dquot_cachep, dquot);
476 }
477 EXPORT_SYMBOL(dquot_destroy);
478
479 static inline void do_destroy_dquot(struct dquot *dquot)
480 {
481         dquot->dq_sb->dq_op->destroy_dquot(dquot);
482 }
483
484 /* Invalidate all dquots on the list. Note that this function is called after
485  * quota is disabled and pointers from inodes removed so there cannot be new
486  * quota users. There can still be some users of quotas due to inodes being
487  * just deleted or pruned by prune_icache() (those are not attached to any
488  * list) or parallel quotactl call. We have to wait for such users.
489  */
490 static void invalidate_dquots(struct super_block *sb, int type)
491 {
492         struct dquot *dquot, *tmp;
493
494 restart:
495         spin_lock(&dq_list_lock);
496         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
497                 if (dquot->dq_sb != sb)
498                         continue;
499                 if (dquot->dq_type != type)
500                         continue;
501                 /* Wait for dquot users */
502                 if (atomic_read(&dquot->dq_count)) {
503                         DEFINE_WAIT(wait);
504
505                         atomic_inc(&dquot->dq_count);
506                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
507                                         TASK_UNINTERRUPTIBLE);
508                         spin_unlock(&dq_list_lock);
509                         /* Once dqput() wakes us up, we know it's time to free
510                          * the dquot.
511                          * IMPORTANT: we rely on the fact that there is always
512                          * at most one process waiting for dquot to free.
513                          * Otherwise dq_count would be > 1 and we would never
514                          * wake up.
515                          */
516                         if (atomic_read(&dquot->dq_count) > 1)
517                                 schedule();
518                         finish_wait(&dquot->dq_wait_unused, &wait);
519                         dqput(dquot);
520                         /* At this moment dquot() need not exist (it could be
521                          * reclaimed by prune_dqcache(). Hence we must
522                          * restart. */
523                         goto restart;
524                 }
525                 /*
526                  * Quota now has no users and it has been written on last
527                  * dqput()
528                  */
529                 remove_dquot_hash(dquot);
530                 remove_free_dquot(dquot);
531                 remove_inuse(dquot);
532                 do_destroy_dquot(dquot);
533         }
534         spin_unlock(&dq_list_lock);
535 }
536
537 /* Call callback for every active dquot on given filesystem */
538 int dquot_scan_active(struct super_block *sb,
539                       int (*fn)(struct dquot *dquot, unsigned long priv),
540                       unsigned long priv)
541 {
542         struct dquot *dquot, *old_dquot = NULL;
543         int ret = 0;
544
545         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
546         spin_lock(&dq_list_lock);
547         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
548                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
549                         continue;
550                 if (dquot->dq_sb != sb)
551                         continue;
552                 /* Now we have active dquot so we can just increase use count */
553                 atomic_inc(&dquot->dq_count);
554                 dqstats.lookups++;
555                 spin_unlock(&dq_list_lock);
556                 dqput(old_dquot);
557                 old_dquot = dquot;
558                 ret = fn(dquot, priv);
559                 if (ret < 0)
560                         goto out;
561                 spin_lock(&dq_list_lock);
562                 /* We are safe to continue now because our dquot could not
563                  * be moved out of the inuse list while we hold the reference */
564         }
565         spin_unlock(&dq_list_lock);
566 out:
567         dqput(old_dquot);
568         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
569         return ret;
570 }
571 EXPORT_SYMBOL(dquot_scan_active);
572
573 int vfs_quota_sync(struct super_block *sb, int type, int wait)
574 {
575         struct list_head *dirty;
576         struct dquot *dquot;
577         struct quota_info *dqopt = sb_dqopt(sb);
578         int cnt;
579
580         mutex_lock(&dqopt->dqonoff_mutex);
581         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
582                 if (type != -1 && cnt != type)
583                         continue;
584                 if (!sb_has_quota_active(sb, cnt))
585                         continue;
586                 spin_lock(&dq_list_lock);
587                 dirty = &dqopt->info[cnt].dqi_dirty_list;
588                 while (!list_empty(dirty)) {
589                         dquot = list_first_entry(dirty, struct dquot,
590                                                  dq_dirty);
591                         /* Dirty and inactive can be only bad dquot... */
592                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
593                                 clear_dquot_dirty(dquot);
594                                 continue;
595                         }
596                         /* Now we have active dquot from which someone is
597                          * holding reference so we can safely just increase
598                          * use count */
599                         atomic_inc(&dquot->dq_count);
600                         dqstats.lookups++;
601                         spin_unlock(&dq_list_lock);
602                         sb->dq_op->write_dquot(dquot);
603                         dqput(dquot);
604                         spin_lock(&dq_list_lock);
605                 }
606                 spin_unlock(&dq_list_lock);
607         }
608
609         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
610                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
611                     && info_dirty(&dqopt->info[cnt]))
612                         sb->dq_op->write_info(sb, cnt);
613         spin_lock(&dq_list_lock);
614         dqstats.syncs++;
615         spin_unlock(&dq_list_lock);
616         mutex_unlock(&dqopt->dqonoff_mutex);
617
618         if (!wait || (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE))
619                 return 0;
620
621         /* This is not very clever (and fast) but currently I don't know about
622          * any other simple way of getting quota data to disk and we must get
623          * them there for userspace to be visible... */
624         if (sb->s_op->sync_fs)
625                 sb->s_op->sync_fs(sb, 1);
626         sync_blockdev(sb->s_bdev);
627
628         /*
629          * Now when everything is written we can discard the pagecache so
630          * that userspace sees the changes.
631          */
632         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
633         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
634                 if (type != -1 && cnt != type)
635                         continue;
636                 if (!sb_has_quota_active(sb, cnt))
637                         continue;
638                 mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
639                                   I_MUTEX_QUOTA);
640                 truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
641                 mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
642         }
643         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
644
645         return 0;
646 }
647 EXPORT_SYMBOL(vfs_quota_sync);
648
649 /* Free unused dquots from cache */
650 static void prune_dqcache(int count)
651 {
652         struct list_head *head;
653         struct dquot *dquot;
654
655         head = free_dquots.prev;
656         while (head != &free_dquots && count) {
657                 dquot = list_entry(head, struct dquot, dq_free);
658                 remove_dquot_hash(dquot);
659                 remove_free_dquot(dquot);
660                 remove_inuse(dquot);
661                 do_destroy_dquot(dquot);
662                 count--;
663                 head = free_dquots.prev;
664         }
665 }
666
667 /*
668  * This is called from kswapd when we think we need some
669  * more memory
670  */
671
672 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
673 {
674         if (nr) {
675                 spin_lock(&dq_list_lock);
676                 prune_dqcache(nr);
677                 spin_unlock(&dq_list_lock);
678         }
679         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
680 }
681
682 static struct shrinker dqcache_shrinker = {
683         .shrink = shrink_dqcache_memory,
684         .seeks = DEFAULT_SEEKS,
685 };
686
687 /*
688  * Put reference to dquot
689  * NOTE: If you change this function please check whether dqput_blocks() works right...
690  */
691 void dqput(struct dquot *dquot)
692 {
693         int ret;
694
695         if (!dquot)
696                 return;
697 #ifdef __DQUOT_PARANOIA
698         if (!atomic_read(&dquot->dq_count)) {
699                 printk("VFS: dqput: trying to free free dquot\n");
700                 printk("VFS: device %s, dquot of %s %d\n",
701                         dquot->dq_sb->s_id,
702                         quotatypes[dquot->dq_type],
703                         dquot->dq_id);
704                 BUG();
705         }
706 #endif
707         
708         spin_lock(&dq_list_lock);
709         dqstats.drops++;
710         spin_unlock(&dq_list_lock);
711 we_slept:
712         spin_lock(&dq_list_lock);
713         if (atomic_read(&dquot->dq_count) > 1) {
714                 /* We have more than one user... nothing to do */
715                 atomic_dec(&dquot->dq_count);
716                 /* Releasing dquot during quotaoff phase? */
717                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_type) &&
718                     atomic_read(&dquot->dq_count) == 1)
719                         wake_up(&dquot->dq_wait_unused);
720                 spin_unlock(&dq_list_lock);
721                 return;
722         }
723         /* Need to release dquot? */
724         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
725                 spin_unlock(&dq_list_lock);
726                 /* Commit dquot before releasing */
727                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
728                 if (ret < 0) {
729                         printk(KERN_ERR "VFS: cannot write quota structure on "
730                                 "device %s (error %d). Quota may get out of "
731                                 "sync!\n", dquot->dq_sb->s_id, ret);
732                         /*
733                          * We clear dirty bit anyway, so that we avoid
734                          * infinite loop here
735                          */
736                         spin_lock(&dq_list_lock);
737                         clear_dquot_dirty(dquot);
738                         spin_unlock(&dq_list_lock);
739                 }
740                 goto we_slept;
741         }
742         /* Clear flag in case dquot was inactive (something bad happened) */
743         clear_dquot_dirty(dquot);
744         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
745                 spin_unlock(&dq_list_lock);
746                 dquot->dq_sb->dq_op->release_dquot(dquot);
747                 goto we_slept;
748         }
749         atomic_dec(&dquot->dq_count);
750 #ifdef __DQUOT_PARANOIA
751         /* sanity check */
752         BUG_ON(!list_empty(&dquot->dq_free));
753 #endif
754         put_dquot_last(dquot);
755         spin_unlock(&dq_list_lock);
756 }
757 EXPORT_SYMBOL(dqput);
758
759 struct dquot *dquot_alloc(struct super_block *sb, int type)
760 {
761         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
762 }
763 EXPORT_SYMBOL(dquot_alloc);
764
765 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
766 {
767         struct dquot *dquot;
768
769         dquot = sb->dq_op->alloc_dquot(sb, type);
770         if(!dquot)
771                 return NULL;
772
773         mutex_init(&dquot->dq_lock);
774         INIT_LIST_HEAD(&dquot->dq_free);
775         INIT_LIST_HEAD(&dquot->dq_inuse);
776         INIT_HLIST_NODE(&dquot->dq_hash);
777         INIT_LIST_HEAD(&dquot->dq_dirty);
778         init_waitqueue_head(&dquot->dq_wait_unused);
779         dquot->dq_sb = sb;
780         dquot->dq_type = type;
781         atomic_set(&dquot->dq_count, 1);
782
783         return dquot;
784 }
785
786 /*
787  * Get reference to dquot
788  *
789  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
790  * destroying our dquot by:
791  *   a) checking for quota flags under dq_list_lock and
792  *   b) getting a reference to dquot before we release dq_list_lock
793  */
794 struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
795 {
796         unsigned int hashent = hashfn(sb, id, type);
797         struct dquot *dquot = NULL, *empty = NULL;
798
799         if (!sb_has_quota_active(sb, type))
800                 return NULL;
801 we_slept:
802         spin_lock(&dq_list_lock);
803         spin_lock(&dq_state_lock);
804         if (!sb_has_quota_active(sb, type)) {
805                 spin_unlock(&dq_state_lock);
806                 spin_unlock(&dq_list_lock);
807                 goto out;
808         }
809         spin_unlock(&dq_state_lock);
810
811         dquot = find_dquot(hashent, sb, id, type);
812         if (!dquot) {
813                 if (!empty) {
814                         spin_unlock(&dq_list_lock);
815                         empty = get_empty_dquot(sb, type);
816                         if (!empty)
817                                 schedule();     /* Try to wait for a moment... */
818                         goto we_slept;
819                 }
820                 dquot = empty;
821                 empty = NULL;
822                 dquot->dq_id = id;
823                 /* all dquots go on the inuse_list */
824                 put_inuse(dquot);
825                 /* hash it first so it can be found */
826                 insert_dquot_hash(dquot);
827                 dqstats.lookups++;
828                 spin_unlock(&dq_list_lock);
829         } else {
830                 if (!atomic_read(&dquot->dq_count))
831                         remove_free_dquot(dquot);
832                 atomic_inc(&dquot->dq_count);
833                 dqstats.cache_hits++;
834                 dqstats.lookups++;
835                 spin_unlock(&dq_list_lock);
836         }
837         /* Wait for dq_lock - after this we know that either dquot_release() is
838          * already finished or it will be canceled due to dq_count > 1 test */
839         wait_on_dquot(dquot);
840         /* Read the dquot / allocate space in quota file */
841         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) &&
842             sb->dq_op->acquire_dquot(dquot) < 0) {
843                 dqput(dquot);
844                 dquot = NULL;
845                 goto out;
846         }
847 #ifdef __DQUOT_PARANOIA
848         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
849 #endif
850 out:
851         if (empty)
852                 do_destroy_dquot(empty);
853
854         return dquot;
855 }
856 EXPORT_SYMBOL(dqget);
857
858 static int dqinit_needed(struct inode *inode, int type)
859 {
860         int cnt;
861
862         if (IS_NOQUOTA(inode))
863                 return 0;
864         if (type != -1)
865                 return !inode->i_dquot[type];
866         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
867                 if (!inode->i_dquot[cnt])
868                         return 1;
869         return 0;
870 }
871
872 /* This routine is guarded by dqonoff_mutex mutex */
873 static void add_dquot_ref(struct super_block *sb, int type)
874 {
875         struct inode *inode, *old_inode = NULL;
876         int reserved = 0;
877
878         spin_lock(&inode_lock);
879         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
880                 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
881                         continue;
882                 if (unlikely(inode_get_rsv_space(inode) > 0))
883                         reserved = 1;
884                 if (!atomic_read(&inode->i_writecount))
885                         continue;
886                 if (!dqinit_needed(inode, type))
887                         continue;
888
889                 __iget(inode);
890                 spin_unlock(&inode_lock);
891
892                 iput(old_inode);
893                 sb->dq_op->initialize(inode, type);
894                 /* We hold a reference to 'inode' so it couldn't have been
895                  * removed from s_inodes list while we dropped the inode_lock.
896                  * We cannot iput the inode now as we can be holding the last
897                  * reference and we cannot iput it under inode_lock. So we
898                  * keep the reference and iput it later. */
899                 old_inode = inode;
900                 spin_lock(&inode_lock);
901         }
902         spin_unlock(&inode_lock);
903         iput(old_inode);
904
905         if (reserved) {
906                 printk(KERN_WARNING "VFS (%s): Writes happened before quota"
907                         " was turned on thus quota information is probably "
908                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
909         }
910 }
911
912 /*
913  * Return 0 if dqput() won't block.
914  * (note that 1 doesn't necessarily mean blocking)
915  */
916 static inline int dqput_blocks(struct dquot *dquot)
917 {
918         if (atomic_read(&dquot->dq_count) <= 1)
919                 return 1;
920         return 0;
921 }
922
923 /*
924  * Remove references to dquots from inode and add dquot to list for freeing
925  * if we have the last referece to dquot
926  * We can't race with anybody because we hold dqptr_sem for writing...
927  */
928 static int remove_inode_dquot_ref(struct inode *inode, int type,
929                                   struct list_head *tofree_head)
930 {
931         struct dquot *dquot = inode->i_dquot[type];
932
933         inode->i_dquot[type] = NULL;
934         if (dquot) {
935                 if (dqput_blocks(dquot)) {
936 #ifdef __DQUOT_PARANOIA
937                         if (atomic_read(&dquot->dq_count) != 1)
938                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
939 #endif
940                         spin_lock(&dq_list_lock);
941                         /* As dquot must have currently users it can't be on
942                          * the free list... */
943                         list_add(&dquot->dq_free, tofree_head);
944                         spin_unlock(&dq_list_lock);
945                         return 1;
946                 }
947                 else
948                         dqput(dquot);   /* We have guaranteed we won't block */
949         }
950         return 0;
951 }
952
953 /*
954  * Free list of dquots
955  * Dquots are removed from inodes and no new references can be got so we are
956  * the only ones holding reference
957  */
958 static void put_dquot_list(struct list_head *tofree_head)
959 {
960         struct list_head *act_head;
961         struct dquot *dquot;
962
963         act_head = tofree_head->next;
964         while (act_head != tofree_head) {
965                 dquot = list_entry(act_head, struct dquot, dq_free);
966                 act_head = act_head->next;
967                 /* Remove dquot from the list so we won't have problems... */
968                 list_del_init(&dquot->dq_free);
969                 dqput(dquot);
970         }
971 }
972
973 static void remove_dquot_ref(struct super_block *sb, int type,
974                 struct list_head *tofree_head)
975 {
976         struct inode *inode;
977
978         spin_lock(&inode_lock);
979         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
980                 /*
981                  *  We have to scan also I_NEW inodes because they can already
982                  *  have quota pointer initialized. Luckily, we need to touch
983                  *  only quota pointers and these have separate locking
984                  *  (dqptr_sem).
985                  */
986                 if (!IS_NOQUOTA(inode))
987                         remove_inode_dquot_ref(inode, type, tofree_head);
988         }
989         spin_unlock(&inode_lock);
990 }
991
992 /* Gather all references from inodes and drop them */
993 static void drop_dquot_ref(struct super_block *sb, int type)
994 {
995         LIST_HEAD(tofree_head);
996
997         if (sb->dq_op) {
998                 down_write(&sb_dqopt(sb)->dqptr_sem);
999                 remove_dquot_ref(sb, type, &tofree_head);
1000                 up_write(&sb_dqopt(sb)->dqptr_sem);
1001                 put_dquot_list(&tofree_head);
1002         }
1003 }
1004
1005 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
1006 {
1007         dquot->dq_dqb.dqb_curinodes += number;
1008 }
1009
1010 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
1011 {
1012         dquot->dq_dqb.dqb_curspace += number;
1013 }
1014
1015 static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
1016 {
1017         dquot->dq_dqb.dqb_rsvspace += number;
1018 }
1019
1020 /*
1021  * Claim reserved quota space
1022  */
1023 static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number)
1024 {
1025         if (dquot->dq_dqb.dqb_rsvspace < number) {
1026                 WARN_ON_ONCE(1);
1027                 number = dquot->dq_dqb.dqb_rsvspace;
1028         }
1029         dquot->dq_dqb.dqb_curspace += number;
1030         dquot->dq_dqb.dqb_rsvspace -= number;
1031 }
1032
1033 static inline
1034 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1035 {
1036         if (dquot->dq_dqb.dqb_rsvspace >= number)
1037                 dquot->dq_dqb.dqb_rsvspace -= number;
1038         else {
1039                 WARN_ON_ONCE(1);
1040                 dquot->dq_dqb.dqb_rsvspace = 0;
1041         }
1042 }
1043
1044 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1045 {
1046         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1047             dquot->dq_dqb.dqb_curinodes >= number)
1048                 dquot->dq_dqb.dqb_curinodes -= number;
1049         else
1050                 dquot->dq_dqb.dqb_curinodes = 0;
1051         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1052                 dquot->dq_dqb.dqb_itime = (time_t) 0;
1053         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1054 }
1055
1056 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1057 {
1058         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1059             dquot->dq_dqb.dqb_curspace >= number)
1060                 dquot->dq_dqb.dqb_curspace -= number;
1061         else
1062                 dquot->dq_dqb.dqb_curspace = 0;
1063         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1064                 dquot->dq_dqb.dqb_btime = (time_t) 0;
1065         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1066 }
1067
1068 static int warning_issued(struct dquot *dquot, const int warntype)
1069 {
1070         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1071                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1072                 ((warntype == QUOTA_NL_IHARDWARN ||
1073                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1074
1075         if (!flag)
1076                 return 0;
1077         return test_and_set_bit(flag, &dquot->dq_flags);
1078 }
1079
1080 #ifdef CONFIG_PRINT_QUOTA_WARNING
1081 static int flag_print_warnings = 1;
1082
1083 static int need_print_warning(struct dquot *dquot)
1084 {
1085         if (!flag_print_warnings)
1086                 return 0;
1087
1088         switch (dquot->dq_type) {
1089                 case USRQUOTA:
1090                         return current_fsuid() == dquot->dq_id;
1091                 case GRPQUOTA:
1092                         return in_group_p(dquot->dq_id);
1093         }
1094         return 0;
1095 }
1096
1097 /* Print warning to user which exceeded quota */
1098 static void print_warning(struct dquot *dquot, const int warntype)
1099 {
1100         char *msg = NULL;
1101         struct tty_struct *tty;
1102
1103         if (warntype == QUOTA_NL_IHARDBELOW ||
1104             warntype == QUOTA_NL_ISOFTBELOW ||
1105             warntype == QUOTA_NL_BHARDBELOW ||
1106             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
1107                 return;
1108
1109         tty = get_current_tty();
1110         if (!tty)
1111                 return;
1112         tty_write_message(tty, dquot->dq_sb->s_id);
1113         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1114                 tty_write_message(tty, ": warning, ");
1115         else
1116                 tty_write_message(tty, ": write failed, ");
1117         tty_write_message(tty, quotatypes[dquot->dq_type]);
1118         switch (warntype) {
1119                 case QUOTA_NL_IHARDWARN:
1120                         msg = " file limit reached.\r\n";
1121                         break;
1122                 case QUOTA_NL_ISOFTLONGWARN:
1123                         msg = " file quota exceeded too long.\r\n";
1124                         break;
1125                 case QUOTA_NL_ISOFTWARN:
1126                         msg = " file quota exceeded.\r\n";
1127                         break;
1128                 case QUOTA_NL_BHARDWARN:
1129                         msg = " block limit reached.\r\n";
1130                         break;
1131                 case QUOTA_NL_BSOFTLONGWARN:
1132                         msg = " block quota exceeded too long.\r\n";
1133                         break;
1134                 case QUOTA_NL_BSOFTWARN:
1135                         msg = " block quota exceeded.\r\n";
1136                         break;
1137         }
1138         tty_write_message(tty, msg);
1139         tty_kref_put(tty);
1140 }
1141 #endif
1142
1143 /*
1144  * Write warnings to the console and send warning messages over netlink.
1145  *
1146  * Note that this function can sleep.
1147  */
1148 static void flush_warnings(struct dquot *const *dquots, char *warntype)
1149 {
1150         struct dquot *dq;
1151         int i;
1152
1153         for (i = 0; i < MAXQUOTAS; i++) {
1154                 dq = dquots[i];
1155                 if (dq && warntype[i] != QUOTA_NL_NOWARN &&
1156                     !warning_issued(dq, warntype[i])) {
1157 #ifdef CONFIG_PRINT_QUOTA_WARNING
1158                         print_warning(dq, warntype[i]);
1159 #endif
1160                         quota_send_warning(dq->dq_type, dq->dq_id,
1161                                            dq->dq_sb->s_dev, warntype[i]);
1162                 }
1163         }
1164 }
1165
1166 static int ignore_hardlimit(struct dquot *dquot)
1167 {
1168         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
1169
1170         return capable(CAP_SYS_RESOURCE) &&
1171                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1172                 !(info->dqi_flags & V1_DQF_RSQUASH));
1173 }
1174
1175 /* needs dq_data_lock */
1176 static int check_idq(struct dquot *dquot, qsize_t inodes, char *warntype)
1177 {
1178         qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1179
1180         *warntype = QUOTA_NL_NOWARN;
1181         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1182             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1183                 return QUOTA_OK;
1184
1185         if (dquot->dq_dqb.dqb_ihardlimit &&
1186             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1187             !ignore_hardlimit(dquot)) {
1188                 *warntype = QUOTA_NL_IHARDWARN;
1189                 return NO_QUOTA;
1190         }
1191
1192         if (dquot->dq_dqb.dqb_isoftlimit &&
1193             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1194             dquot->dq_dqb.dqb_itime &&
1195             get_seconds() >= dquot->dq_dqb.dqb_itime &&
1196             !ignore_hardlimit(dquot)) {
1197                 *warntype = QUOTA_NL_ISOFTLONGWARN;
1198                 return NO_QUOTA;
1199         }
1200
1201         if (dquot->dq_dqb.dqb_isoftlimit &&
1202             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1203             dquot->dq_dqb.dqb_itime == 0) {
1204                 *warntype = QUOTA_NL_ISOFTWARN;
1205                 dquot->dq_dqb.dqb_itime = get_seconds() +
1206                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1207         }
1208
1209         return QUOTA_OK;
1210 }
1211
1212 /* needs dq_data_lock */
1213 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
1214 {
1215         qsize_t tspace;
1216         struct super_block *sb = dquot->dq_sb;
1217
1218         *warntype = QUOTA_NL_NOWARN;
1219         if (!sb_has_quota_limits_enabled(sb, dquot->dq_type) ||
1220             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1221                 return QUOTA_OK;
1222
1223         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1224                 + space;
1225
1226         if (dquot->dq_dqb.dqb_bhardlimit &&
1227             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1228             !ignore_hardlimit(dquot)) {
1229                 if (!prealloc)
1230                         *warntype = QUOTA_NL_BHARDWARN;
1231                 return NO_QUOTA;
1232         }
1233
1234         if (dquot->dq_dqb.dqb_bsoftlimit &&
1235             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1236             dquot->dq_dqb.dqb_btime &&
1237             get_seconds() >= dquot->dq_dqb.dqb_btime &&
1238             !ignore_hardlimit(dquot)) {
1239                 if (!prealloc)
1240                         *warntype = QUOTA_NL_BSOFTLONGWARN;
1241                 return NO_QUOTA;
1242         }
1243
1244         if (dquot->dq_dqb.dqb_bsoftlimit &&
1245             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1246             dquot->dq_dqb.dqb_btime == 0) {
1247                 if (!prealloc) {
1248                         *warntype = QUOTA_NL_BSOFTWARN;
1249                         dquot->dq_dqb.dqb_btime = get_seconds() +
1250                             sb_dqopt(sb)->info[dquot->dq_type].dqi_bgrace;
1251                 }
1252                 else
1253                         /*
1254                          * We don't allow preallocation to exceed softlimit so exceeding will
1255                          * be always printed
1256                          */
1257                         return NO_QUOTA;
1258         }
1259
1260         return QUOTA_OK;
1261 }
1262
1263 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1264 {
1265         qsize_t newinodes;
1266
1267         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1268             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1269             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type))
1270                 return QUOTA_NL_NOWARN;
1271
1272         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1273         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1274                 return QUOTA_NL_ISOFTBELOW;
1275         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1276             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1277                 return QUOTA_NL_IHARDBELOW;
1278         return QUOTA_NL_NOWARN;
1279 }
1280
1281 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1282 {
1283         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1284             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1285                 return QUOTA_NL_NOWARN;
1286
1287         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1288                 return QUOTA_NL_BSOFTBELOW;
1289         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1290             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1291                 return QUOTA_NL_BHARDBELOW;
1292         return QUOTA_NL_NOWARN;
1293 }
1294
1295 /*
1296  *      Initialize quota pointers in inode
1297  *      We do things in a bit complicated way but by that we avoid calling
1298  *      dqget() and thus filesystem callbacks under dqptr_sem.
1299  */
1300 int dquot_initialize(struct inode *inode, int type)
1301 {
1302         unsigned int id = 0;
1303         int cnt, ret = 0;
1304         struct dquot *got[MAXQUOTAS];
1305         struct super_block *sb = inode->i_sb;
1306         qsize_t rsv;
1307
1308         /* First test before acquiring mutex - solves deadlocks when we
1309          * re-enter the quota code and are already holding the mutex */
1310         if (IS_NOQUOTA(inode))
1311                 return 0;
1312
1313         /* First get references to structures we might need. */
1314         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1315                 got[cnt] = NULL;
1316                 if (type != -1 && cnt != type)
1317                         continue;
1318                 switch (cnt) {
1319                 case USRQUOTA:
1320                         id = inode->i_uid;
1321                         break;
1322                 case GRPQUOTA:
1323                         id = inode->i_gid;
1324                         break;
1325                 }
1326                 got[cnt] = dqget(sb, id, cnt);
1327         }
1328
1329         down_write(&sb_dqopt(sb)->dqptr_sem);
1330         if (IS_NOQUOTA(inode))
1331                 goto out_err;
1332         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1333                 if (type != -1 && cnt != type)
1334                         continue;
1335                 /* Avoid races with quotaoff() */
1336                 if (!sb_has_quota_active(sb, cnt))
1337                         continue;
1338                 if (!inode->i_dquot[cnt]) {
1339                         inode->i_dquot[cnt] = got[cnt];
1340                         got[cnt] = NULL;
1341                         /*
1342                          * Make quota reservation system happy if someone
1343                          * did a write before quota was turned on
1344                          */
1345                         rsv = inode_get_rsv_space(inode);
1346                         if (unlikely(rsv))
1347                                 dquot_resv_space(inode->i_dquot[cnt], rsv);
1348                 }
1349         }
1350 out_err:
1351         up_write(&sb_dqopt(sb)->dqptr_sem);
1352         /* Drop unused references */
1353         dqput_all(got);
1354         return ret;
1355 }
1356 EXPORT_SYMBOL(dquot_initialize);
1357
1358 /*
1359  *      Release all quotas referenced by inode
1360  */
1361 int dquot_drop(struct inode *inode)
1362 {
1363         int cnt;
1364         struct dquot *put[MAXQUOTAS];
1365
1366         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1367         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1368                 put[cnt] = inode->i_dquot[cnt];
1369                 inode->i_dquot[cnt] = NULL;
1370         }
1371         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1372         dqput_all(put);
1373         return 0;
1374 }
1375 EXPORT_SYMBOL(dquot_drop);
1376
1377 /* Wrapper to remove references to quota structures from inode */
1378 void vfs_dq_drop(struct inode *inode)
1379 {
1380         /* Here we can get arbitrary inode from clear_inode() so we have
1381          * to be careful. OTOH we don't need locking as quota operations
1382          * are allowed to change only at mount time */
1383         if (!IS_NOQUOTA(inode) && inode->i_sb && inode->i_sb->dq_op
1384             && inode->i_sb->dq_op->drop) {
1385                 int cnt;
1386                 /* Test before calling to rule out calls from proc and such
1387                  * where we are not allowed to block. Note that this is
1388                  * actually reliable test even without the lock - the caller
1389                  * must assure that nobody can come after the DQUOT_DROP and
1390                  * add quota pointers back anyway */
1391                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1392                         if (inode->i_dquot[cnt])
1393                                 break;
1394                 if (cnt < MAXQUOTAS)
1395                         inode->i_sb->dq_op->drop(inode);
1396         }
1397 }
1398 EXPORT_SYMBOL(vfs_dq_drop);
1399
1400 /*
1401  * inode_reserved_space is managed internally by quota, and protected by
1402  * i_lock similar to i_blocks+i_bytes.
1403  */
1404 static qsize_t *inode_reserved_space(struct inode * inode)
1405 {
1406         /* Filesystem must explicitly define it's own method in order to use
1407          * quota reservation interface */
1408         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1409         return inode->i_sb->dq_op->get_reserved_space(inode);
1410 }
1411
1412 void inode_add_rsv_space(struct inode *inode, qsize_t number)
1413 {
1414         spin_lock(&inode->i_lock);
1415         *inode_reserved_space(inode) += number;
1416         spin_unlock(&inode->i_lock);
1417 }
1418 EXPORT_SYMBOL(inode_add_rsv_space);
1419
1420 void inode_claim_rsv_space(struct inode *inode, qsize_t number)
1421 {
1422         spin_lock(&inode->i_lock);
1423         *inode_reserved_space(inode) -= number;
1424         __inode_add_bytes(inode, number);
1425         spin_unlock(&inode->i_lock);
1426 }
1427 EXPORT_SYMBOL(inode_claim_rsv_space);
1428
1429 void inode_sub_rsv_space(struct inode *inode, qsize_t number)
1430 {
1431         spin_lock(&inode->i_lock);
1432         *inode_reserved_space(inode) -= number;
1433         spin_unlock(&inode->i_lock);
1434 }
1435 EXPORT_SYMBOL(inode_sub_rsv_space);
1436
1437 static qsize_t inode_get_rsv_space(struct inode *inode)
1438 {
1439         qsize_t ret;
1440
1441         if (!inode->i_sb->dq_op->get_reserved_space)
1442                 return 0;
1443         spin_lock(&inode->i_lock);
1444         ret = *inode_reserved_space(inode);
1445         spin_unlock(&inode->i_lock);
1446         return ret;
1447 }
1448
1449 static void inode_incr_space(struct inode *inode, qsize_t number,
1450                                 int reserve)
1451 {
1452         if (reserve)
1453                 inode_add_rsv_space(inode, number);
1454         else
1455                 inode_add_bytes(inode, number);
1456 }
1457
1458 static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
1459 {
1460         if (reserve)
1461                 inode_sub_rsv_space(inode, number);
1462         else
1463                 inode_sub_bytes(inode, number);
1464 }
1465
1466 /*
1467  * Following four functions update i_blocks+i_bytes fields and
1468  * quota information (together with appropriate checks)
1469  * NOTE: We absolutely rely on the fact that caller dirties
1470  * the inode (usually macros in quotaops.h care about this) and
1471  * holds a handle for the current transaction so that dquot write and
1472  * inode write go into the same transaction.
1473  */
1474
1475 /*
1476  * This operation can block, but only after everything is updated
1477  */
1478 int __dquot_alloc_space(struct inode *inode, qsize_t number,
1479                         int warn, int reserve)
1480 {
1481         int cnt, ret = QUOTA_OK;
1482         char warntype[MAXQUOTAS];
1483
1484         /*
1485          * First test before acquiring mutex - solves deadlocks when we
1486          * re-enter the quota code and are already holding the mutex
1487          */
1488         if (IS_NOQUOTA(inode)) {
1489                 inode_incr_space(inode, number, reserve);
1490                 goto out;
1491         }
1492
1493         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1494         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1495                 warntype[cnt] = QUOTA_NL_NOWARN;
1496
1497         spin_lock(&dq_data_lock);
1498         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1499                 if (!inode->i_dquot[cnt])
1500                         continue;
1501                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt)
1502                     == NO_QUOTA) {
1503                         ret = NO_QUOTA;
1504                         spin_unlock(&dq_data_lock);
1505                         goto out_flush_warn;
1506                 }
1507         }
1508         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1509                 if (!inode->i_dquot[cnt])
1510                         continue;
1511                 if (reserve)
1512                         dquot_resv_space(inode->i_dquot[cnt], number);
1513                 else
1514                         dquot_incr_space(inode->i_dquot[cnt], number);
1515         }
1516         inode_incr_space(inode, number, reserve);
1517         spin_unlock(&dq_data_lock);
1518
1519         if (reserve)
1520                 goto out_flush_warn;
1521         mark_all_dquot_dirty(inode->i_dquot);
1522 out_flush_warn:
1523         flush_warnings(inode->i_dquot, warntype);
1524         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1525 out:
1526         return ret;
1527 }
1528
1529 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1530 {
1531         return __dquot_alloc_space(inode, number, warn, 0);
1532 }
1533 EXPORT_SYMBOL(dquot_alloc_space);
1534
1535 int dquot_reserve_space(struct inode *inode, qsize_t number, int warn)
1536 {
1537         return __dquot_alloc_space(inode, number, warn, 1);
1538 }
1539 EXPORT_SYMBOL(dquot_reserve_space);
1540
1541 /*
1542  * This operation can block, but only after everything is updated
1543  */
1544 int dquot_alloc_inode(const struct inode *inode, qsize_t number)
1545 {
1546         int cnt, ret = NO_QUOTA;
1547         char warntype[MAXQUOTAS];
1548
1549         /* First test before acquiring mutex - solves deadlocks when we
1550          * re-enter the quota code and are already holding the mutex */
1551         if (IS_NOQUOTA(inode))
1552                 return QUOTA_OK;
1553         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1554                 warntype[cnt] = QUOTA_NL_NOWARN;
1555         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1556         spin_lock(&dq_data_lock);
1557         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1558                 if (!inode->i_dquot[cnt])
1559                         continue;
1560                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt)
1561                     == NO_QUOTA)
1562                         goto warn_put_all;
1563         }
1564
1565         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1566                 if (!inode->i_dquot[cnt])
1567                         continue;
1568                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1569         }
1570         ret = QUOTA_OK;
1571 warn_put_all:
1572         spin_unlock(&dq_data_lock);
1573         if (ret == QUOTA_OK)
1574                 mark_all_dquot_dirty(inode->i_dquot);
1575         flush_warnings(inode->i_dquot, warntype);
1576         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1577         return ret;
1578 }
1579 EXPORT_SYMBOL(dquot_alloc_inode);
1580
1581 int dquot_claim_space(struct inode *inode, qsize_t number)
1582 {
1583         int cnt;
1584         int ret = QUOTA_OK;
1585
1586         if (IS_NOQUOTA(inode)) {
1587                 inode_claim_rsv_space(inode, number);
1588                 goto out;
1589         }
1590
1591         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1592         spin_lock(&dq_data_lock);
1593         /* Claim reserved quotas to allocated quotas */
1594         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1595                 if (inode->i_dquot[cnt])
1596                         dquot_claim_reserved_space(inode->i_dquot[cnt],
1597                                                         number);
1598         }
1599         /* Update inode bytes */
1600         inode_claim_rsv_space(inode, number);
1601         spin_unlock(&dq_data_lock);
1602         mark_all_dquot_dirty(inode->i_dquot);
1603         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1604 out:
1605         return ret;
1606 }
1607 EXPORT_SYMBOL(dquot_claim_space);
1608
1609 /*
1610  * This operation can block, but only after everything is updated
1611  */
1612 int __dquot_free_space(struct inode *inode, qsize_t number, int reserve)
1613 {
1614         unsigned int cnt;
1615         char warntype[MAXQUOTAS];
1616
1617         /* First test before acquiring mutex - solves deadlocks when we
1618          * re-enter the quota code and are already holding the mutex */
1619         if (IS_NOQUOTA(inode)) {
1620                 inode_decr_space(inode, number, reserve);
1621                 return QUOTA_OK;
1622         }
1623
1624         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1625         spin_lock(&dq_data_lock);
1626         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1627                 if (!inode->i_dquot[cnt])
1628                         continue;
1629                 warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
1630                 if (reserve)
1631                         dquot_free_reserved_space(inode->i_dquot[cnt], number);
1632                 else
1633                         dquot_decr_space(inode->i_dquot[cnt], number);
1634         }
1635         inode_decr_space(inode, number, reserve);
1636         spin_unlock(&dq_data_lock);
1637
1638         if (reserve)
1639                 goto out_unlock;
1640         mark_all_dquot_dirty(inode->i_dquot);
1641 out_unlock:
1642         flush_warnings(inode->i_dquot, warntype);
1643         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1644         return QUOTA_OK;
1645 }
1646
1647 int dquot_free_space(struct inode *inode, qsize_t number)
1648 {
1649         return  __dquot_free_space(inode, number, 0);
1650 }
1651 EXPORT_SYMBOL(dquot_free_space);
1652
1653 /*
1654  * Release reserved quota space
1655  */
1656 void dquot_release_reserved_space(struct inode *inode, qsize_t number)
1657 {
1658         __dquot_free_space(inode, number, 1);
1659
1660 }
1661 EXPORT_SYMBOL(dquot_release_reserved_space);
1662
1663 /*
1664  * This operation can block, but only after everything is updated
1665  */
1666 int dquot_free_inode(const struct inode *inode, qsize_t number)
1667 {
1668         unsigned int cnt;
1669         char warntype[MAXQUOTAS];
1670
1671         /* First test before acquiring mutex - solves deadlocks when we
1672          * re-enter the quota code and are already holding the mutex */
1673         if (IS_NOQUOTA(inode))
1674                 return QUOTA_OK;
1675
1676         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1677         spin_lock(&dq_data_lock);
1678         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1679                 if (!inode->i_dquot[cnt])
1680                         continue;
1681                 warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
1682                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1683         }
1684         spin_unlock(&dq_data_lock);
1685         mark_all_dquot_dirty(inode->i_dquot);
1686         flush_warnings(inode->i_dquot, warntype);
1687         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1688         return QUOTA_OK;
1689 }
1690 EXPORT_SYMBOL(dquot_free_inode);
1691
1692 /*
1693  * Transfer the number of inode and blocks from one diskquota to an other.
1694  *
1695  * This operation can block, but only after everything is updated
1696  * A transaction must be started when entering this function.
1697  */
1698 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1699 {
1700         qsize_t space, cur_space;
1701         qsize_t rsv_space = 0;
1702         struct dquot *transfer_from[MAXQUOTAS];
1703         struct dquot *transfer_to[MAXQUOTAS];
1704         int cnt, ret = QUOTA_OK;
1705         int chuid = iattr->ia_valid & ATTR_UID && inode->i_uid != iattr->ia_uid,
1706             chgid = iattr->ia_valid & ATTR_GID && inode->i_gid != iattr->ia_gid;
1707         char warntype_to[MAXQUOTAS];
1708         char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
1709
1710         /* First test before acquiring mutex - solves deadlocks when we
1711          * re-enter the quota code and are already holding the mutex */
1712         if (IS_NOQUOTA(inode))
1713                 return QUOTA_OK;
1714         /* Initialize the arrays */
1715         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1716                 transfer_from[cnt] = NULL;
1717                 transfer_to[cnt] = NULL;
1718                 warntype_to[cnt] = QUOTA_NL_NOWARN;
1719         }
1720         if (chuid)
1721                 transfer_to[USRQUOTA] = dqget(inode->i_sb, iattr->ia_uid,
1722                                               USRQUOTA);
1723         if (chgid)
1724                 transfer_to[GRPQUOTA] = dqget(inode->i_sb, iattr->ia_gid,
1725                                               GRPQUOTA);
1726
1727         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1728         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1729                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1730                 goto put_all;
1731         }
1732         spin_lock(&dq_data_lock);
1733         cur_space = inode_get_bytes(inode);
1734         rsv_space = inode_get_rsv_space(inode);
1735         space = cur_space + rsv_space;
1736         /* Build the transfer_from list and check the limits */
1737         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1738                 if (!transfer_to[cnt])
1739                         continue;
1740                 transfer_from[cnt] = inode->i_dquot[cnt];
1741                 if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
1742                     NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
1743                     warntype_to + cnt) == NO_QUOTA)
1744                         goto over_quota;
1745         }
1746
1747         /*
1748          * Finally perform the needed transfer from transfer_from to transfer_to
1749          */
1750         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1751                 /*
1752                  * Skip changes for same uid or gid or for turned off quota-type.
1753                  */
1754                 if (!transfer_to[cnt])
1755                         continue;
1756
1757                 /* Due to IO error we might not have transfer_from[] structure */
1758                 if (transfer_from[cnt]) {
1759                         warntype_from_inodes[cnt] =
1760                                 info_idq_free(transfer_from[cnt], 1);
1761                         warntype_from_space[cnt] =
1762                                 info_bdq_free(transfer_from[cnt], space);
1763                         dquot_decr_inodes(transfer_from[cnt], 1);
1764                         dquot_decr_space(transfer_from[cnt], cur_space);
1765                         dquot_free_reserved_space(transfer_from[cnt],
1766                                                   rsv_space);
1767                 }
1768
1769                 dquot_incr_inodes(transfer_to[cnt], 1);
1770                 dquot_incr_space(transfer_to[cnt], cur_space);
1771                 dquot_resv_space(transfer_to[cnt], rsv_space);
1772
1773                 inode->i_dquot[cnt] = transfer_to[cnt];
1774         }
1775         spin_unlock(&dq_data_lock);
1776         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1777
1778         mark_all_dquot_dirty(transfer_from);
1779         mark_all_dquot_dirty(transfer_to);
1780         /* The reference we got is transferred to the inode */
1781         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1782                 transfer_to[cnt] = NULL;
1783 warn_put_all:
1784         flush_warnings(transfer_to, warntype_to);
1785         flush_warnings(transfer_from, warntype_from_inodes);
1786         flush_warnings(transfer_from, warntype_from_space);
1787 put_all:
1788         dqput_all(transfer_from);
1789         dqput_all(transfer_to);
1790         return ret;
1791 over_quota:
1792         spin_unlock(&dq_data_lock);
1793         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1794         /* Clear dquot pointers we don't want to dqput() */
1795         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1796                 transfer_from[cnt] = NULL;
1797         ret = NO_QUOTA;
1798         goto warn_put_all;
1799 }
1800 EXPORT_SYMBOL(dquot_transfer);
1801
1802 /* Wrapper for transferring ownership of an inode */
1803 int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
1804 {
1805         if (sb_any_quota_active(inode->i_sb) && !IS_NOQUOTA(inode)) {
1806                 vfs_dq_init(inode);
1807                 if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
1808                         return 1;
1809         }
1810         return 0;
1811 }
1812 EXPORT_SYMBOL(vfs_dq_transfer);
1813
1814 /*
1815  * Write info of quota file to disk
1816  */
1817 int dquot_commit_info(struct super_block *sb, int type)
1818 {
1819         int ret;
1820         struct quota_info *dqopt = sb_dqopt(sb);
1821
1822         mutex_lock(&dqopt->dqio_mutex);
1823         ret = dqopt->ops[type]->write_file_info(sb, type);
1824         mutex_unlock(&dqopt->dqio_mutex);
1825         return ret;
1826 }
1827 EXPORT_SYMBOL(dquot_commit_info);
1828
1829 /*
1830  * Definitions of diskquota operations.
1831  */
1832 const struct dquot_operations dquot_operations = {
1833         .initialize     = dquot_initialize,
1834         .drop           = dquot_drop,
1835         .alloc_space    = dquot_alloc_space,
1836         .alloc_inode    = dquot_alloc_inode,
1837         .free_space     = dquot_free_space,
1838         .free_inode     = dquot_free_inode,
1839         .transfer       = dquot_transfer,
1840         .write_dquot    = dquot_commit,
1841         .acquire_dquot  = dquot_acquire,
1842         .release_dquot  = dquot_release,
1843         .mark_dirty     = dquot_mark_dquot_dirty,
1844         .write_info     = dquot_commit_info,
1845         .alloc_dquot    = dquot_alloc,
1846         .destroy_dquot  = dquot_destroy,
1847 };
1848
1849 /*
1850  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1851  */
1852 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
1853 {
1854         int cnt, ret = 0;
1855         struct quota_info *dqopt = sb_dqopt(sb);
1856         struct inode *toputinode[MAXQUOTAS];
1857
1858         /* Cannot turn off usage accounting without turning off limits, or
1859          * suspend quotas and simultaneously turn quotas off. */
1860         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
1861             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
1862             DQUOT_USAGE_ENABLED)))
1863                 return -EINVAL;
1864
1865         /* We need to serialize quota_off() for device */
1866         mutex_lock(&dqopt->dqonoff_mutex);
1867
1868         /*
1869          * Skip everything if there's nothing to do. We have to do this because
1870          * sometimes we are called when fill_super() failed and calling
1871          * sync_fs() in such cases does no good.
1872          */
1873         if (!sb_any_quota_loaded(sb)) {
1874                 mutex_unlock(&dqopt->dqonoff_mutex);
1875                 return 0;
1876         }
1877         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1878                 toputinode[cnt] = NULL;
1879                 if (type != -1 && cnt != type)
1880                         continue;
1881                 if (!sb_has_quota_loaded(sb, cnt))
1882                         continue;
1883
1884                 if (flags & DQUOT_SUSPENDED) {
1885                         spin_lock(&dq_state_lock);
1886                         dqopt->flags |=
1887                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
1888                         spin_unlock(&dq_state_lock);
1889                 } else {
1890                         spin_lock(&dq_state_lock);
1891                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
1892                         /* Turning off suspended quotas? */
1893                         if (!sb_has_quota_loaded(sb, cnt) &&
1894                             sb_has_quota_suspended(sb, cnt)) {
1895                                 dqopt->flags &= ~dquot_state_flag(
1896                                                         DQUOT_SUSPENDED, cnt);
1897                                 spin_unlock(&dq_state_lock);
1898                                 iput(dqopt->files[cnt]);
1899                                 dqopt->files[cnt] = NULL;
1900                                 continue;
1901                         }
1902                         spin_unlock(&dq_state_lock);
1903                 }
1904
1905                 /* We still have to keep quota loaded? */
1906                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
1907                         continue;
1908
1909                 /* Note: these are blocking operations */
1910                 drop_dquot_ref(sb, cnt);
1911                 invalidate_dquots(sb, cnt);
1912                 /*
1913                  * Now all dquots should be invalidated, all writes done so we
1914                  * should be only users of the info. No locks needed.
1915                  */
1916                 if (info_dirty(&dqopt->info[cnt]))
1917                         sb->dq_op->write_info(sb, cnt);
1918                 if (dqopt->ops[cnt]->free_file_info)
1919                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1920                 put_quota_format(dqopt->info[cnt].dqi_format);
1921
1922                 toputinode[cnt] = dqopt->files[cnt];
1923                 if (!sb_has_quota_loaded(sb, cnt))
1924                         dqopt->files[cnt] = NULL;
1925                 dqopt->info[cnt].dqi_flags = 0;
1926                 dqopt->info[cnt].dqi_igrace = 0;
1927                 dqopt->info[cnt].dqi_bgrace = 0;
1928                 dqopt->ops[cnt] = NULL;
1929         }
1930         mutex_unlock(&dqopt->dqonoff_mutex);
1931
1932         /* Skip syncing and setting flags if quota files are hidden */
1933         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
1934                 goto put_inodes;
1935
1936         /* Sync the superblock so that buffers with quota data are written to
1937          * disk (and so userspace sees correct data afterwards). */
1938         if (sb->s_op->sync_fs)
1939                 sb->s_op->sync_fs(sb, 1);
1940         sync_blockdev(sb->s_bdev);
1941         /* Now the quota files are just ordinary files and we can set the
1942          * inode flags back. Moreover we discard the pagecache so that
1943          * userspace sees the writes we did bypassing the pagecache. We
1944          * must also discard the blockdev buffers so that we see the
1945          * changes done by userspace on the next quotaon() */
1946         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1947                 if (toputinode[cnt]) {
1948                         mutex_lock(&dqopt->dqonoff_mutex);
1949                         /* If quota was reenabled in the meantime, we have
1950                          * nothing to do */
1951                         if (!sb_has_quota_loaded(sb, cnt)) {
1952                                 mutex_lock_nested(&toputinode[cnt]->i_mutex,
1953                                                   I_MUTEX_QUOTA);
1954                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1955                                   S_NOATIME | S_NOQUOTA);
1956                                 truncate_inode_pages(&toputinode[cnt]->i_data,
1957                                                      0);
1958                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1959                                 mark_inode_dirty(toputinode[cnt]);
1960                         }
1961                         mutex_unlock(&dqopt->dqonoff_mutex);
1962                 }
1963         if (sb->s_bdev)
1964                 invalidate_bdev(sb->s_bdev);
1965 put_inodes:
1966         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1967                 if (toputinode[cnt]) {
1968                         /* On remount RO, we keep the inode pointer so that we
1969                          * can reenable quota on the subsequent remount RW. We
1970                          * have to check 'flags' variable and not use sb_has_
1971                          * function because another quotaon / quotaoff could
1972                          * change global state before we got here. We refuse
1973                          * to suspend quotas when there is pending delete on
1974                          * the quota file... */
1975                         if (!(flags & DQUOT_SUSPENDED))
1976                                 iput(toputinode[cnt]);
1977                         else if (!toputinode[cnt]->i_nlink)
1978                                 ret = -EBUSY;
1979                 }
1980         return ret;
1981 }
1982 EXPORT_SYMBOL(vfs_quota_disable);
1983
1984 int vfs_quota_off(struct super_block *sb, int type, int remount)
1985 {
1986         return vfs_quota_disable(sb, type, remount ? DQUOT_SUSPENDED :
1987                                  (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED));
1988 }
1989 EXPORT_SYMBOL(vfs_quota_off);
1990 /*
1991  *      Turn quotas on on a device
1992  */
1993
1994 /*
1995  * Helper function to turn quotas on when we already have the inode of
1996  * quota file and no quota information is loaded.
1997  */
1998 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
1999         unsigned int flags)
2000 {
2001         struct quota_format_type *fmt = find_quota_format(format_id);
2002         struct super_block *sb = inode->i_sb;
2003         struct quota_info *dqopt = sb_dqopt(sb);
2004         int error;
2005         int oldflags = -1;
2006
2007         if (!fmt)
2008                 return -ESRCH;
2009         if (!S_ISREG(inode->i_mode)) {
2010                 error = -EACCES;
2011                 goto out_fmt;
2012         }
2013         if (IS_RDONLY(inode)) {
2014                 error = -EROFS;
2015                 goto out_fmt;
2016         }
2017         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
2018                 error = -EINVAL;
2019                 goto out_fmt;
2020         }
2021         /* Usage always has to be set... */
2022         if (!(flags & DQUOT_USAGE_ENABLED)) {
2023                 error = -EINVAL;
2024                 goto out_fmt;
2025         }
2026
2027         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2028                 /* As we bypass the pagecache we must now flush the inode so
2029                  * that we see all the changes from userspace... */
2030                 write_inode_now(inode, 1);
2031                 /* And now flush the block cache so that kernel sees the
2032                  * changes */
2033                 invalidate_bdev(sb->s_bdev);
2034         }
2035         mutex_lock(&dqopt->dqonoff_mutex);
2036         if (sb_has_quota_loaded(sb, type)) {
2037                 error = -EBUSY;
2038                 goto out_lock;
2039         }
2040
2041         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2042                 /* We don't want quota and atime on quota files (deadlocks
2043                  * possible) Also nobody should write to the file - we use
2044                  * special IO operations which ignore the immutable bit. */
2045                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2046                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
2047                                              S_NOQUOTA);
2048                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
2049                 mutex_unlock(&inode->i_mutex);
2050                 /*
2051                  * When S_NOQUOTA is set, remove dquot references as no more
2052                  * references can be added
2053                  */
2054                 sb->dq_op->drop(inode);
2055         }
2056
2057         error = -EIO;
2058         dqopt->files[type] = igrab(inode);
2059         if (!dqopt->files[type])
2060                 goto out_lock;
2061         error = -EINVAL;
2062         if (!fmt->qf_ops->check_quota_file(sb, type))
2063                 goto out_file_init;
2064
2065         dqopt->ops[type] = fmt->qf_ops;
2066         dqopt->info[type].dqi_format = fmt;
2067         dqopt->info[type].dqi_fmt_id = format_id;
2068         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2069         mutex_lock(&dqopt->dqio_mutex);
2070         error = dqopt->ops[type]->read_file_info(sb, type);
2071         if (error < 0) {
2072                 mutex_unlock(&dqopt->dqio_mutex);
2073                 goto out_file_init;
2074         }
2075         mutex_unlock(&dqopt->dqio_mutex);
2076         spin_lock(&dq_state_lock);
2077         dqopt->flags |= dquot_state_flag(flags, type);
2078         spin_unlock(&dq_state_lock);
2079
2080         add_dquot_ref(sb, type);
2081         mutex_unlock(&dqopt->dqonoff_mutex);
2082
2083         return 0;
2084
2085 out_file_init:
2086         dqopt->files[type] = NULL;
2087         iput(inode);
2088 out_lock:
2089         if (oldflags != -1) {
2090                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
2091                 /* Set the flags back (in the case of accidental quotaon()
2092                  * on a wrong file we don't want to mess up the flags) */
2093                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
2094                 inode->i_flags |= oldflags;
2095                 mutex_unlock(&inode->i_mutex);
2096         }
2097         mutex_unlock(&dqopt->dqonoff_mutex);
2098 out_fmt:
2099         put_quota_format(fmt);
2100
2101         return error; 
2102 }
2103
2104 /* Reenable quotas on remount RW */
2105 static int vfs_quota_on_remount(struct super_block *sb, int type)
2106 {
2107         struct quota_info *dqopt = sb_dqopt(sb);
2108         struct inode *inode;
2109         int ret;
2110         unsigned int flags;
2111
2112         mutex_lock(&dqopt->dqonoff_mutex);
2113         if (!sb_has_quota_suspended(sb, type)) {
2114                 mutex_unlock(&dqopt->dqonoff_mutex);
2115                 return 0;
2116         }
2117         inode = dqopt->files[type];
2118         dqopt->files[type] = NULL;
2119         spin_lock(&dq_state_lock);
2120         flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2121                                                 DQUOT_LIMITS_ENABLED, type);
2122         dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, type);
2123         spin_unlock(&dq_state_lock);
2124         mutex_unlock(&dqopt->dqonoff_mutex);
2125
2126         flags = dquot_generic_flag(flags, type);
2127         ret = vfs_load_quota_inode(inode, type, dqopt->info[type].dqi_fmt_id,
2128                                    flags);
2129         iput(inode);
2130
2131         return ret;
2132 }
2133
2134 int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
2135                       struct path *path)
2136 {
2137         int error = security_quota_on(path->dentry);
2138         if (error)
2139                 return error;
2140         /* Quota file not on the same filesystem? */
2141         if (path->mnt->mnt_sb != sb)
2142                 error = -EXDEV;
2143         else
2144                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
2145                                              format_id, DQUOT_USAGE_ENABLED |
2146                                              DQUOT_LIMITS_ENABLED);
2147         return error;
2148 }
2149 EXPORT_SYMBOL(vfs_quota_on_path);
2150
2151 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
2152                  int remount)
2153 {
2154         struct path path;
2155         int error;
2156
2157         if (remount)
2158                 return vfs_quota_on_remount(sb, type);
2159
2160         error = kern_path(name, LOOKUP_FOLLOW, &path);
2161         if (!error) {
2162                 error = vfs_quota_on_path(sb, type, format_id, &path);
2163                 path_put(&path);
2164         }
2165         return error;
2166 }
2167 EXPORT_SYMBOL(vfs_quota_on);
2168
2169 /*
2170  * More powerful function for turning on quotas allowing setting
2171  * of individual quota flags
2172  */
2173 int vfs_quota_enable(struct inode *inode, int type, int format_id,
2174                 unsigned int flags)
2175 {
2176         int ret = 0;
2177         struct super_block *sb = inode->i_sb;
2178         struct quota_info *dqopt = sb_dqopt(sb);
2179
2180         /* Just unsuspend quotas? */
2181         if (flags & DQUOT_SUSPENDED)
2182                 return vfs_quota_on_remount(sb, type);
2183         if (!flags)
2184                 return 0;
2185         /* Just updating flags needed? */
2186         if (sb_has_quota_loaded(sb, type)) {
2187                 mutex_lock(&dqopt->dqonoff_mutex);
2188                 /* Now do a reliable test... */
2189                 if (!sb_has_quota_loaded(sb, type)) {
2190                         mutex_unlock(&dqopt->dqonoff_mutex);
2191                         goto load_quota;
2192                 }
2193                 if (flags & DQUOT_USAGE_ENABLED &&
2194                     sb_has_quota_usage_enabled(sb, type)) {
2195                         ret = -EBUSY;
2196                         goto out_lock;
2197                 }
2198                 if (flags & DQUOT_LIMITS_ENABLED &&
2199                     sb_has_quota_limits_enabled(sb, type)) {
2200                         ret = -EBUSY;
2201                         goto out_lock;
2202                 }
2203                 spin_lock(&dq_state_lock);
2204                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2205                 spin_unlock(&dq_state_lock);
2206 out_lock:
2207                 mutex_unlock(&dqopt->dqonoff_mutex);
2208                 return ret;
2209         }
2210
2211 load_quota:
2212         return vfs_load_quota_inode(inode, type, format_id, flags);
2213 }
2214 EXPORT_SYMBOL(vfs_quota_enable);
2215
2216 /*
2217  * This function is used when filesystem needs to initialize quotas
2218  * during mount time.
2219  */
2220 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
2221                 int format_id, int type)
2222 {
2223         struct dentry *dentry;
2224         int error;
2225
2226         mutex_lock(&sb->s_root->d_inode->i_mutex);
2227         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2228         mutex_unlock(&sb->s_root->d_inode->i_mutex);
2229         if (IS_ERR(dentry))
2230                 return PTR_ERR(dentry);
2231
2232         if (!dentry->d_inode) {
2233                 error = -ENOENT;
2234                 goto out;
2235         }
2236
2237         error = security_quota_on(dentry);
2238         if (!error)
2239                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2240                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2241
2242 out:
2243         dput(dentry);
2244         return error;
2245 }
2246 EXPORT_SYMBOL(vfs_quota_on_mount);
2247
2248 /* Wrapper to turn on quotas when remounting rw */
2249 int vfs_dq_quota_on_remount(struct super_block *sb)
2250 {
2251         int cnt;
2252         int ret = 0, err;
2253
2254         if (!sb->s_qcop || !sb->s_qcop->quota_on)
2255                 return -ENOSYS;
2256         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2257                 err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
2258                 if (err < 0 && !ret)
2259                         ret = err;
2260         }
2261         return ret;
2262 }
2263 EXPORT_SYMBOL(vfs_dq_quota_on_remount);
2264
2265 static inline qsize_t qbtos(qsize_t blocks)
2266 {
2267         return blocks << QIF_DQBLKSIZE_BITS;
2268 }
2269
2270 static inline qsize_t stoqb(qsize_t space)
2271 {
2272         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2273 }
2274
2275 /* Generic routine for getting common part of quota structure */
2276 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
2277 {
2278         struct mem_dqblk *dm = &dquot->dq_dqb;
2279
2280         spin_lock(&dq_data_lock);
2281         di->dqb_bhardlimit = stoqb(dm->dqb_bhardlimit);
2282         di->dqb_bsoftlimit = stoqb(dm->dqb_bsoftlimit);
2283         di->dqb_curspace = dm->dqb_curspace + dm->dqb_rsvspace;
2284         di->dqb_ihardlimit = dm->dqb_ihardlimit;
2285         di->dqb_isoftlimit = dm->dqb_isoftlimit;
2286         di->dqb_curinodes = dm->dqb_curinodes;
2287         di->dqb_btime = dm->dqb_btime;
2288         di->dqb_itime = dm->dqb_itime;
2289         di->dqb_valid = QIF_ALL;
2290         spin_unlock(&dq_data_lock);
2291 }
2292
2293 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id,
2294                   struct if_dqblk *di)
2295 {
2296         struct dquot *dquot;
2297
2298         dquot = dqget(sb, id, type);
2299         if (!dquot)
2300                 return -ESRCH;
2301         do_get_dqblk(dquot, di);
2302         dqput(dquot);
2303
2304         return 0;
2305 }
2306 EXPORT_SYMBOL(vfs_get_dqblk);
2307
2308 /* Generic routine for setting common part of quota structure */
2309 static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
2310 {
2311         struct mem_dqblk *dm = &dquot->dq_dqb;
2312         int check_blim = 0, check_ilim = 0;
2313         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
2314
2315         if ((di->dqb_valid & QIF_BLIMITS &&
2316              (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
2317               di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
2318             (di->dqb_valid & QIF_ILIMITS &&
2319              (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
2320               di->dqb_isoftlimit > dqi->dqi_maxilimit)))
2321                 return -ERANGE;
2322
2323         spin_lock(&dq_data_lock);
2324         if (di->dqb_valid & QIF_SPACE) {
2325                 dm->dqb_curspace = di->dqb_curspace - dm->dqb_rsvspace;
2326                 check_blim = 1;
2327                 __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2328         }
2329         if (di->dqb_valid & QIF_BLIMITS) {
2330                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
2331                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
2332                 check_blim = 1;
2333                 __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2334         }
2335         if (di->dqb_valid & QIF_INODES) {
2336                 dm->dqb_curinodes = di->dqb_curinodes;
2337                 check_ilim = 1;
2338                 __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2339         }
2340         if (di->dqb_valid & QIF_ILIMITS) {
2341                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
2342                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
2343                 check_ilim = 1;
2344                 __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2345         }
2346         if (di->dqb_valid & QIF_BTIME) {
2347                 dm->dqb_btime = di->dqb_btime;
2348                 check_blim = 1;
2349                 __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2350         }
2351         if (di->dqb_valid & QIF_ITIME) {
2352                 dm->dqb_itime = di->dqb_itime;
2353                 check_ilim = 1;
2354                 __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2355         }
2356
2357         if (check_blim) {
2358                 if (!dm->dqb_bsoftlimit ||
2359                     dm->dqb_curspace < dm->dqb_bsoftlimit) {
2360                         dm->dqb_btime = 0;
2361                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2362                 } else if (!(di->dqb_valid & QIF_BTIME))
2363                         /* Set grace only if user hasn't provided his own... */
2364                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2365         }
2366         if (check_ilim) {
2367                 if (!dm->dqb_isoftlimit ||
2368                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2369                         dm->dqb_itime = 0;
2370                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2371                 } else if (!(di->dqb_valid & QIF_ITIME))
2372                         /* Set grace only if user hasn't provided his own... */
2373                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2374         }
2375         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2376             dm->dqb_isoftlimit)
2377                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2378         else
2379                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2380         spin_unlock(&dq_data_lock);
2381         mark_dquot_dirty(dquot);
2382
2383         return 0;
2384 }
2385
2386 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id,
2387                   struct if_dqblk *di)
2388 {
2389         struct dquot *dquot;
2390         int rc;
2391
2392         dquot = dqget(sb, id, type);
2393         if (!dquot) {
2394                 rc = -ESRCH;
2395                 goto out;
2396         }
2397         rc = do_set_dqblk(dquot, di);
2398         dqput(dquot);
2399 out:
2400         return rc;
2401 }
2402 EXPORT_SYMBOL(vfs_set_dqblk);
2403
2404 /* Generic routine for getting common part of quota file information */
2405 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2406 {
2407         struct mem_dqinfo *mi;
2408   
2409         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2410         if (!sb_has_quota_active(sb, type)) {
2411                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2412                 return -ESRCH;
2413         }
2414         mi = sb_dqopt(sb)->info + type;
2415         spin_lock(&dq_data_lock);
2416         ii->dqi_bgrace = mi->dqi_bgrace;
2417         ii->dqi_igrace = mi->dqi_igrace;
2418         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
2419         ii->dqi_valid = IIF_ALL;
2420         spin_unlock(&dq_data_lock);
2421         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2422         return 0;
2423 }
2424 EXPORT_SYMBOL(vfs_get_dqinfo);
2425
2426 /* Generic routine for setting common part of quota file information */
2427 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2428 {
2429         struct mem_dqinfo *mi;
2430         int err = 0;
2431
2432         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2433         if (!sb_has_quota_active(sb, type)) {
2434                 err = -ESRCH;
2435                 goto out;
2436         }
2437         mi = sb_dqopt(sb)->info + type;
2438         spin_lock(&dq_data_lock);
2439         if (ii->dqi_valid & IIF_BGRACE)
2440                 mi->dqi_bgrace = ii->dqi_bgrace;
2441         if (ii->dqi_valid & IIF_IGRACE)
2442                 mi->dqi_igrace = ii->dqi_igrace;
2443         if (ii->dqi_valid & IIF_FLAGS)
2444                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) |
2445                                 (ii->dqi_flags & DQF_MASK);
2446         spin_unlock(&dq_data_lock);
2447         mark_info_dirty(sb, type);
2448         /* Force write to disk */
2449         sb->dq_op->write_info(sb, type);
2450 out:
2451         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2452         return err;
2453 }
2454 EXPORT_SYMBOL(vfs_set_dqinfo);
2455
2456 const struct quotactl_ops vfs_quotactl_ops = {
2457         .quota_on       = vfs_quota_on,
2458         .quota_off      = vfs_quota_off,
2459         .quota_sync     = vfs_quota_sync,
2460         .get_info       = vfs_get_dqinfo,
2461         .set_info       = vfs_set_dqinfo,
2462         .get_dqblk      = vfs_get_dqblk,
2463         .set_dqblk      = vfs_set_dqblk
2464 };
2465
2466 static ctl_table fs_dqstats_table[] = {
2467         {
2468                 .procname       = "lookups",
2469                 .data           = &dqstats.lookups,
2470                 .maxlen         = sizeof(int),
2471                 .mode           = 0444,
2472                 .proc_handler   = proc_dointvec,
2473         },
2474         {
2475                 .procname       = "drops",
2476                 .data           = &dqstats.drops,
2477                 .maxlen         = sizeof(int),
2478                 .mode           = 0444,
2479                 .proc_handler   = proc_dointvec,
2480         },
2481         {
2482                 .procname       = "reads",
2483                 .data           = &dqstats.reads,
2484                 .maxlen         = sizeof(int),
2485                 .mode           = 0444,
2486                 .proc_handler   = proc_dointvec,
2487         },
2488         {
2489                 .procname       = "writes",
2490                 .data           = &dqstats.writes,
2491                 .maxlen         = sizeof(int),
2492                 .mode           = 0444,
2493                 .proc_handler   = proc_dointvec,
2494         },
2495         {
2496                 .procname       = "cache_hits",
2497                 .data           = &dqstats.cache_hits,
2498                 .maxlen         = sizeof(int),
2499                 .mode           = 0444,
2500                 .proc_handler   = proc_dointvec,
2501         },
2502         {
2503                 .procname       = "allocated_dquots",
2504                 .data           = &dqstats.allocated_dquots,
2505                 .maxlen         = sizeof(int),
2506                 .mode           = 0444,
2507                 .proc_handler   = proc_dointvec,
2508         },
2509         {
2510                 .procname       = "free_dquots",
2511                 .data           = &dqstats.free_dquots,
2512                 .maxlen         = sizeof(int),
2513                 .mode           = 0444,
2514                 .proc_handler   = proc_dointvec,
2515         },
2516         {
2517                 .procname       = "syncs",
2518                 .data           = &dqstats.syncs,
2519                 .maxlen         = sizeof(int),
2520                 .mode           = 0444,
2521                 .proc_handler   = proc_dointvec,
2522         },
2523 #ifdef CONFIG_PRINT_QUOTA_WARNING
2524         {
2525                 .procname       = "warnings",
2526                 .data           = &flag_print_warnings,
2527                 .maxlen         = sizeof(int),
2528                 .mode           = 0644,
2529                 .proc_handler   = proc_dointvec,
2530         },
2531 #endif
2532         { },
2533 };
2534
2535 static ctl_table fs_table[] = {
2536         {
2537                 .procname       = "quota",
2538                 .mode           = 0555,
2539                 .child          = fs_dqstats_table,
2540         },
2541         { },
2542 };
2543
2544 static ctl_table sys_table[] = {
2545         {
2546                 .procname       = "fs",
2547                 .mode           = 0555,
2548                 .child          = fs_table,
2549         },
2550         { },
2551 };
2552
2553 static int __init dquot_init(void)
2554 {
2555         int i;
2556         unsigned long nr_hash, order;
2557
2558         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2559
2560         register_sysctl_table(sys_table);
2561
2562         dquot_cachep = kmem_cache_create("dquot",
2563                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2564                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2565                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2566                         NULL);
2567
2568         order = 0;
2569         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2570         if (!dquot_hash)
2571                 panic("Cannot create dquot hash table");
2572
2573         /* Find power-of-two hlist_heads which can fit into allocation */
2574         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2575         dq_hash_bits = 0;
2576         do {
2577                 dq_hash_bits++;
2578         } while (nr_hash >> dq_hash_bits);
2579         dq_hash_bits--;
2580
2581         nr_hash = 1UL << dq_hash_bits;
2582         dq_hash_mask = nr_hash - 1;
2583         for (i = 0; i < nr_hash; i++)
2584                 INIT_HLIST_HEAD(dquot_hash + i);
2585
2586         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2587                         nr_hash, order, (PAGE_SIZE << order));
2588
2589         register_shrinker(&dqcache_shrinker);
2590
2591         return 0;
2592 }
2593 module_init(dquot_init);