tun: Limit amount of queued packets per device
[linux-2.6] / fs / 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 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
81 #include <net/netlink.h>
82 #include <net/genetlink.h>
83 #endif
84
85 #include <asm/uaccess.h>
86
87 #define __DQUOT_PARANOIA
88
89 /*
90  * There are three quota SMP locks. dq_list_lock protects all lists with quotas
91  * and quota formats, dqstats structure containing statistics about the lists
92  * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
93  * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
94  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
95  * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
96  * modifications of quota state (on quotaon and quotaoff) and readers who care
97  * about latest values take it as well.
98  *
99  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
100  *   dq_list_lock > dq_state_lock
101  *
102  * Note that some things (eg. sb pointer, type, id) doesn't change during
103  * the life of the dquot structure and so needn't to be protected by a lock
104  *
105  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
106  * operation is just reading pointers from inode (or not using them at all) the
107  * read lock is enough. If pointers are altered function must hold write lock
108  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
109  * for altering the flag i_mutex is also needed).
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 DEFINE_SPINLOCK(dq_list_lock);
133 static DEFINE_SPINLOCK(dq_state_lock);
134 DEFINE_SPINLOCK(dq_data_lock);
135
136 static char *quotatypes[] = INITQFNAMES;
137 static struct quota_format_type *quota_formats; /* List of registered formats */
138 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
139
140 /* SLAB cache for dquot structures */
141 static struct kmem_cache *dquot_cachep;
142
143 int register_quota_format(struct quota_format_type *fmt)
144 {
145         spin_lock(&dq_list_lock);
146         fmt->qf_next = quota_formats;
147         quota_formats = fmt;
148         spin_unlock(&dq_list_lock);
149         return 0;
150 }
151
152 void unregister_quota_format(struct quota_format_type *fmt)
153 {
154         struct quota_format_type **actqf;
155
156         spin_lock(&dq_list_lock);
157         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
158         if (*actqf)
159                 *actqf = (*actqf)->qf_next;
160         spin_unlock(&dq_list_lock);
161 }
162
163 static struct quota_format_type *find_quota_format(int id)
164 {
165         struct quota_format_type *actqf;
166
167         spin_lock(&dq_list_lock);
168         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
169         if (!actqf || !try_module_get(actqf->qf_owner)) {
170                 int qm;
171
172                 spin_unlock(&dq_list_lock);
173                 
174                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
175                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
176                         return NULL;
177
178                 spin_lock(&dq_list_lock);
179                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
180                 if (actqf && !try_module_get(actqf->qf_owner))
181                         actqf = NULL;
182         }
183         spin_unlock(&dq_list_lock);
184         return actqf;
185 }
186
187 static void put_quota_format(struct quota_format_type *fmt)
188 {
189         module_put(fmt->qf_owner);
190 }
191
192 /*
193  * Dquot List Management:
194  * The quota code uses three lists for dquot management: the inuse_list,
195  * free_dquots, and dquot_hash[] array. A single dquot structure may be
196  * on all three lists, depending on its current state.
197  *
198  * All dquots are placed to the end of inuse_list when first created, and this
199  * list is used for invalidate operation, which must look at every dquot.
200  *
201  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
202  * and this list is searched whenever we need an available dquot.  Dquots are
203  * removed from the list as soon as they are used again, and
204  * dqstats.free_dquots gives the number of dquots on the list. When
205  * dquot is invalidated it's completely released from memory.
206  *
207  * Dquots with a specific identity (device, type and id) are placed on
208  * one of the dquot_hash[] hash chains. The provides an efficient search
209  * mechanism to locate a specific dquot.
210  */
211
212 static LIST_HEAD(inuse_list);
213 static LIST_HEAD(free_dquots);
214 static unsigned int dq_hash_bits, dq_hash_mask;
215 static struct hlist_head *dquot_hash;
216
217 struct dqstats dqstats;
218
219 static inline unsigned int
220 hashfn(const struct super_block *sb, unsigned int id, int type)
221 {
222         unsigned long tmp;
223
224         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
225         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
226 }
227
228 /*
229  * Following list functions expect dq_list_lock to be held
230  */
231 static inline void insert_dquot_hash(struct dquot *dquot)
232 {
233         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
234         hlist_add_head(&dquot->dq_hash, head);
235 }
236
237 static inline void remove_dquot_hash(struct dquot *dquot)
238 {
239         hlist_del_init(&dquot->dq_hash);
240 }
241
242 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
243 {
244         struct hlist_node *node;
245         struct dquot *dquot;
246
247         hlist_for_each (node, dquot_hash+hashent) {
248                 dquot = hlist_entry(node, struct dquot, dq_hash);
249                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
250                         return dquot;
251         }
252         return NODQUOT;
253 }
254
255 /* Add a dquot to the tail of the free list */
256 static inline void put_dquot_last(struct dquot *dquot)
257 {
258         list_add_tail(&dquot->dq_free, &free_dquots);
259         dqstats.free_dquots++;
260 }
261
262 static inline void remove_free_dquot(struct dquot *dquot)
263 {
264         if (list_empty(&dquot->dq_free))
265                 return;
266         list_del_init(&dquot->dq_free);
267         dqstats.free_dquots--;
268 }
269
270 static inline void put_inuse(struct dquot *dquot)
271 {
272         /* We add to the back of inuse list so we don't have to restart
273          * when traversing this list and we block */
274         list_add_tail(&dquot->dq_inuse, &inuse_list);
275         dqstats.allocated_dquots++;
276 }
277
278 static inline void remove_inuse(struct dquot *dquot)
279 {
280         dqstats.allocated_dquots--;
281         list_del(&dquot->dq_inuse);
282 }
283 /*
284  * End of list functions needing dq_list_lock
285  */
286
287 static void wait_on_dquot(struct dquot *dquot)
288 {
289         mutex_lock(&dquot->dq_lock);
290         mutex_unlock(&dquot->dq_lock);
291 }
292
293 static inline int dquot_dirty(struct dquot *dquot)
294 {
295         return test_bit(DQ_MOD_B, &dquot->dq_flags);
296 }
297
298 static inline int mark_dquot_dirty(struct dquot *dquot)
299 {
300         return dquot->dq_sb->dq_op->mark_dirty(dquot);
301 }
302
303 int dquot_mark_dquot_dirty(struct dquot *dquot)
304 {
305         spin_lock(&dq_list_lock);
306         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
307                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
308                                 info[dquot->dq_type].dqi_dirty_list);
309         spin_unlock(&dq_list_lock);
310         return 0;
311 }
312
313 /* This function needs dq_list_lock */
314 static inline int clear_dquot_dirty(struct dquot *dquot)
315 {
316         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
317                 return 0;
318         list_del_init(&dquot->dq_dirty);
319         return 1;
320 }
321
322 void mark_info_dirty(struct super_block *sb, int type)
323 {
324         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
325 }
326 EXPORT_SYMBOL(mark_info_dirty);
327
328 /*
329  *      Read dquot from disk and alloc space for it
330  */
331
332 int dquot_acquire(struct dquot *dquot)
333 {
334         int ret = 0, ret2 = 0;
335         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
336
337         mutex_lock(&dquot->dq_lock);
338         mutex_lock(&dqopt->dqio_mutex);
339         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
340                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
341         if (ret < 0)
342                 goto out_iolock;
343         set_bit(DQ_READ_B, &dquot->dq_flags);
344         /* Instantiate dquot if needed */
345         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
346                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
347                 /* Write the info if needed */
348                 if (info_dirty(&dqopt->info[dquot->dq_type]))
349                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
350                 if (ret < 0)
351                         goto out_iolock;
352                 if (ret2 < 0) {
353                         ret = ret2;
354                         goto out_iolock;
355                 }
356         }
357         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
358 out_iolock:
359         mutex_unlock(&dqopt->dqio_mutex);
360         mutex_unlock(&dquot->dq_lock);
361         return ret;
362 }
363
364 /*
365  *      Write dquot to disk
366  */
367 int dquot_commit(struct dquot *dquot)
368 {
369         int ret = 0, ret2 = 0;
370         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
371
372         mutex_lock(&dqopt->dqio_mutex);
373         spin_lock(&dq_list_lock);
374         if (!clear_dquot_dirty(dquot)) {
375                 spin_unlock(&dq_list_lock);
376                 goto out_sem;
377         }
378         spin_unlock(&dq_list_lock);
379         /* Inactive dquot can be only if there was error during read/init
380          * => we have better not writing it */
381         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
382                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
383                 if (info_dirty(&dqopt->info[dquot->dq_type]))
384                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
385                 if (ret >= 0)
386                         ret = ret2;
387         }
388 out_sem:
389         mutex_unlock(&dqopt->dqio_mutex);
390         return ret;
391 }
392
393 /*
394  *      Release dquot
395  */
396 int dquot_release(struct dquot *dquot)
397 {
398         int ret = 0, ret2 = 0;
399         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
400
401         mutex_lock(&dquot->dq_lock);
402         /* Check whether we are not racing with some other dqget() */
403         if (atomic_read(&dquot->dq_count) > 1)
404                 goto out_dqlock;
405         mutex_lock(&dqopt->dqio_mutex);
406         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
407                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
408                 /* Write the info */
409                 if (info_dirty(&dqopt->info[dquot->dq_type]))
410                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
411                 if (ret >= 0)
412                         ret = ret2;
413         }
414         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
415         mutex_unlock(&dqopt->dqio_mutex);
416 out_dqlock:
417         mutex_unlock(&dquot->dq_lock);
418         return ret;
419 }
420
421 void dquot_destroy(struct dquot *dquot)
422 {
423         kmem_cache_free(dquot_cachep, dquot);
424 }
425 EXPORT_SYMBOL(dquot_destroy);
426
427 static inline void do_destroy_dquot(struct dquot *dquot)
428 {
429         dquot->dq_sb->dq_op->destroy_dquot(dquot);
430 }
431
432 /* Invalidate all dquots on the list. Note that this function is called after
433  * quota is disabled and pointers from inodes removed so there cannot be new
434  * quota users. There can still be some users of quotas due to inodes being
435  * just deleted or pruned by prune_icache() (those are not attached to any
436  * list) or parallel quotactl call. We have to wait for such users.
437  */
438 static void invalidate_dquots(struct super_block *sb, int type)
439 {
440         struct dquot *dquot, *tmp;
441
442 restart:
443         spin_lock(&dq_list_lock);
444         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
445                 if (dquot->dq_sb != sb)
446                         continue;
447                 if (dquot->dq_type != type)
448                         continue;
449                 /* Wait for dquot users */
450                 if (atomic_read(&dquot->dq_count)) {
451                         DEFINE_WAIT(wait);
452
453                         atomic_inc(&dquot->dq_count);
454                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
455                                         TASK_UNINTERRUPTIBLE);
456                         spin_unlock(&dq_list_lock);
457                         /* Once dqput() wakes us up, we know it's time to free
458                          * the dquot.
459                          * IMPORTANT: we rely on the fact that there is always
460                          * at most one process waiting for dquot to free.
461                          * Otherwise dq_count would be > 1 and we would never
462                          * wake up.
463                          */
464                         if (atomic_read(&dquot->dq_count) > 1)
465                                 schedule();
466                         finish_wait(&dquot->dq_wait_unused, &wait);
467                         dqput(dquot);
468                         /* At this moment dquot() need not exist (it could be
469                          * reclaimed by prune_dqcache(). Hence we must
470                          * restart. */
471                         goto restart;
472                 }
473                 /*
474                  * Quota now has no users and it has been written on last
475                  * dqput()
476                  */
477                 remove_dquot_hash(dquot);
478                 remove_free_dquot(dquot);
479                 remove_inuse(dquot);
480                 do_destroy_dquot(dquot);
481         }
482         spin_unlock(&dq_list_lock);
483 }
484
485 /* Call callback for every active dquot on given filesystem */
486 int dquot_scan_active(struct super_block *sb,
487                       int (*fn)(struct dquot *dquot, unsigned long priv),
488                       unsigned long priv)
489 {
490         struct dquot *dquot, *old_dquot = NULL;
491         int ret = 0;
492
493         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
494         spin_lock(&dq_list_lock);
495         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
496                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
497                         continue;
498                 if (dquot->dq_sb != sb)
499                         continue;
500                 /* Now we have active dquot so we can just increase use count */
501                 atomic_inc(&dquot->dq_count);
502                 dqstats.lookups++;
503                 spin_unlock(&dq_list_lock);
504                 dqput(old_dquot);
505                 old_dquot = dquot;
506                 ret = fn(dquot, priv);
507                 if (ret < 0)
508                         goto out;
509                 spin_lock(&dq_list_lock);
510                 /* We are safe to continue now because our dquot could not
511                  * be moved out of the inuse list while we hold the reference */
512         }
513         spin_unlock(&dq_list_lock);
514 out:
515         dqput(old_dquot);
516         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
517         return ret;
518 }
519
520 int vfs_quota_sync(struct super_block *sb, int type)
521 {
522         struct list_head *dirty;
523         struct dquot *dquot;
524         struct quota_info *dqopt = sb_dqopt(sb);
525         int cnt;
526
527         mutex_lock(&dqopt->dqonoff_mutex);
528         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
529                 if (type != -1 && cnt != type)
530                         continue;
531                 if (!sb_has_quota_active(sb, cnt))
532                         continue;
533                 spin_lock(&dq_list_lock);
534                 dirty = &dqopt->info[cnt].dqi_dirty_list;
535                 while (!list_empty(dirty)) {
536                         dquot = list_first_entry(dirty, struct dquot, dq_dirty);
537                         /* Dirty and inactive can be only bad dquot... */
538                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
539                                 clear_dquot_dirty(dquot);
540                                 continue;
541                         }
542                         /* Now we have active dquot from which someone is
543                          * holding reference so we can safely just increase
544                          * use count */
545                         atomic_inc(&dquot->dq_count);
546                         dqstats.lookups++;
547                         spin_unlock(&dq_list_lock);
548                         sb->dq_op->write_dquot(dquot);
549                         dqput(dquot);
550                         spin_lock(&dq_list_lock);
551                 }
552                 spin_unlock(&dq_list_lock);
553         }
554
555         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
556                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
557                     && info_dirty(&dqopt->info[cnt]))
558                         sb->dq_op->write_info(sb, cnt);
559         spin_lock(&dq_list_lock);
560         dqstats.syncs++;
561         spin_unlock(&dq_list_lock);
562         mutex_unlock(&dqopt->dqonoff_mutex);
563
564         return 0;
565 }
566
567 /* Free unused dquots from cache */
568 static void prune_dqcache(int count)
569 {
570         struct list_head *head;
571         struct dquot *dquot;
572
573         head = free_dquots.prev;
574         while (head != &free_dquots && count) {
575                 dquot = list_entry(head, struct dquot, dq_free);
576                 remove_dquot_hash(dquot);
577                 remove_free_dquot(dquot);
578                 remove_inuse(dquot);
579                 do_destroy_dquot(dquot);
580                 count--;
581                 head = free_dquots.prev;
582         }
583 }
584
585 /*
586  * This is called from kswapd when we think we need some
587  * more memory
588  */
589
590 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
591 {
592         if (nr) {
593                 spin_lock(&dq_list_lock);
594                 prune_dqcache(nr);
595                 spin_unlock(&dq_list_lock);
596         }
597         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
598 }
599
600 static struct shrinker dqcache_shrinker = {
601         .shrink = shrink_dqcache_memory,
602         .seeks = DEFAULT_SEEKS,
603 };
604
605 /*
606  * Put reference to dquot
607  * NOTE: If you change this function please check whether dqput_blocks() works right...
608  */
609 void dqput(struct dquot *dquot)
610 {
611         int ret;
612
613         if (!dquot)
614                 return;
615 #ifdef __DQUOT_PARANOIA
616         if (!atomic_read(&dquot->dq_count)) {
617                 printk("VFS: dqput: trying to free free dquot\n");
618                 printk("VFS: device %s, dquot of %s %d\n",
619                         dquot->dq_sb->s_id,
620                         quotatypes[dquot->dq_type],
621                         dquot->dq_id);
622                 BUG();
623         }
624 #endif
625         
626         spin_lock(&dq_list_lock);
627         dqstats.drops++;
628         spin_unlock(&dq_list_lock);
629 we_slept:
630         spin_lock(&dq_list_lock);
631         if (atomic_read(&dquot->dq_count) > 1) {
632                 /* We have more than one user... nothing to do */
633                 atomic_dec(&dquot->dq_count);
634                 /* Releasing dquot during quotaoff phase? */
635                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_type) &&
636                     atomic_read(&dquot->dq_count) == 1)
637                         wake_up(&dquot->dq_wait_unused);
638                 spin_unlock(&dq_list_lock);
639                 return;
640         }
641         /* Need to release dquot? */
642         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
643                 spin_unlock(&dq_list_lock);
644                 /* Commit dquot before releasing */
645                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
646                 if (ret < 0) {
647                         printk(KERN_ERR "VFS: cannot write quota structure on "
648                                 "device %s (error %d). Quota may get out of "
649                                 "sync!\n", dquot->dq_sb->s_id, ret);
650                         /*
651                          * We clear dirty bit anyway, so that we avoid
652                          * infinite loop here
653                          */
654                         spin_lock(&dq_list_lock);
655                         clear_dquot_dirty(dquot);
656                         spin_unlock(&dq_list_lock);
657                 }
658                 goto we_slept;
659         }
660         /* Clear flag in case dquot was inactive (something bad happened) */
661         clear_dquot_dirty(dquot);
662         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
663                 spin_unlock(&dq_list_lock);
664                 dquot->dq_sb->dq_op->release_dquot(dquot);
665                 goto we_slept;
666         }
667         atomic_dec(&dquot->dq_count);
668 #ifdef __DQUOT_PARANOIA
669         /* sanity check */
670         BUG_ON(!list_empty(&dquot->dq_free));
671 #endif
672         put_dquot_last(dquot);
673         spin_unlock(&dq_list_lock);
674 }
675
676 struct dquot *dquot_alloc(struct super_block *sb, int type)
677 {
678         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
679 }
680 EXPORT_SYMBOL(dquot_alloc);
681
682 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
683 {
684         struct dquot *dquot;
685
686         dquot = sb->dq_op->alloc_dquot(sb, type);
687         if(!dquot)
688                 return NODQUOT;
689
690         mutex_init(&dquot->dq_lock);
691         INIT_LIST_HEAD(&dquot->dq_free);
692         INIT_LIST_HEAD(&dquot->dq_inuse);
693         INIT_HLIST_NODE(&dquot->dq_hash);
694         INIT_LIST_HEAD(&dquot->dq_dirty);
695         init_waitqueue_head(&dquot->dq_wait_unused);
696         dquot->dq_sb = sb;
697         dquot->dq_type = type;
698         atomic_set(&dquot->dq_count, 1);
699
700         return dquot;
701 }
702
703 /*
704  * Get reference to dquot
705  *
706  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
707  * destroying our dquot by:
708  *   a) checking for quota flags under dq_list_lock and
709  *   b) getting a reference to dquot before we release dq_list_lock
710  */
711 struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
712 {
713         unsigned int hashent = hashfn(sb, id, type);
714         struct dquot *dquot = NODQUOT, *empty = NODQUOT;
715
716         if (!sb_has_quota_active(sb, type))
717                 return NODQUOT;
718 we_slept:
719         spin_lock(&dq_list_lock);
720         spin_lock(&dq_state_lock);
721         if (!sb_has_quota_active(sb, type)) {
722                 spin_unlock(&dq_state_lock);
723                 spin_unlock(&dq_list_lock);
724                 goto out;
725         }
726         spin_unlock(&dq_state_lock);
727
728         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
729                 if (empty == NODQUOT) {
730                         spin_unlock(&dq_list_lock);
731                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
732                                 schedule();     /* Try to wait for a moment... */
733                         goto we_slept;
734                 }
735                 dquot = empty;
736                 empty = NODQUOT;
737                 dquot->dq_id = id;
738                 /* all dquots go on the inuse_list */
739                 put_inuse(dquot);
740                 /* hash it first so it can be found */
741                 insert_dquot_hash(dquot);
742                 dqstats.lookups++;
743                 spin_unlock(&dq_list_lock);
744         } else {
745                 if (!atomic_read(&dquot->dq_count))
746                         remove_free_dquot(dquot);
747                 atomic_inc(&dquot->dq_count);
748                 dqstats.cache_hits++;
749                 dqstats.lookups++;
750                 spin_unlock(&dq_list_lock);
751         }
752         /* Wait for dq_lock - after this we know that either dquot_release() is already
753          * finished or it will be canceled due to dq_count > 1 test */
754         wait_on_dquot(dquot);
755         /* Read the dquot and instantiate it (everything done only if needed) */
756         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
757                 dqput(dquot);
758                 dquot = NODQUOT;
759                 goto out;
760         }
761 #ifdef __DQUOT_PARANOIA
762         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
763 #endif
764 out:
765         if (empty)
766                 do_destroy_dquot(empty);
767
768         return dquot;
769 }
770
771 static int dqinit_needed(struct inode *inode, int type)
772 {
773         int cnt;
774
775         if (IS_NOQUOTA(inode))
776                 return 0;
777         if (type != -1)
778                 return inode->i_dquot[type] == NODQUOT;
779         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
780                 if (inode->i_dquot[cnt] == NODQUOT)
781                         return 1;
782         return 0;
783 }
784
785 /* This routine is guarded by dqonoff_mutex mutex */
786 static void add_dquot_ref(struct super_block *sb, int type)
787 {
788         struct inode *inode, *old_inode = NULL;
789
790         spin_lock(&inode_lock);
791         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
792                 if (!atomic_read(&inode->i_writecount))
793                         continue;
794                 if (!dqinit_needed(inode, type))
795                         continue;
796                 if (inode->i_state & (I_FREEING|I_WILL_FREE))
797                         continue;
798
799                 __iget(inode);
800                 spin_unlock(&inode_lock);
801
802                 iput(old_inode);
803                 sb->dq_op->initialize(inode, type);
804                 /* We hold a reference to 'inode' so it couldn't have been
805                  * removed from s_inodes list while we dropped the inode_lock.
806                  * We cannot iput the inode now as we can be holding the last
807                  * reference and we cannot iput it under inode_lock. So we
808                  * keep the reference and iput it later. */
809                 old_inode = inode;
810                 spin_lock(&inode_lock);
811         }
812         spin_unlock(&inode_lock);
813         iput(old_inode);
814 }
815
816 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
817 static inline int dqput_blocks(struct dquot *dquot)
818 {
819         if (atomic_read(&dquot->dq_count) <= 1)
820                 return 1;
821         return 0;
822 }
823
824 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
825 /* We can't race with anybody because we hold dqptr_sem for writing... */
826 static int remove_inode_dquot_ref(struct inode *inode, int type,
827                                   struct list_head *tofree_head)
828 {
829         struct dquot *dquot = inode->i_dquot[type];
830
831         inode->i_dquot[type] = NODQUOT;
832         if (dquot != NODQUOT) {
833                 if (dqput_blocks(dquot)) {
834 #ifdef __DQUOT_PARANOIA
835                         if (atomic_read(&dquot->dq_count) != 1)
836                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
837 #endif
838                         spin_lock(&dq_list_lock);
839                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
840                         spin_unlock(&dq_list_lock);
841                         return 1;
842                 }
843                 else
844                         dqput(dquot);   /* We have guaranteed we won't block */
845         }
846         return 0;
847 }
848
849 /* Free list of dquots - called from inode.c */
850 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
851 static void put_dquot_list(struct list_head *tofree_head)
852 {
853         struct list_head *act_head;
854         struct dquot *dquot;
855
856         act_head = tofree_head->next;
857         /* So now we have dquots on the list... Just free them */
858         while (act_head != tofree_head) {
859                 dquot = list_entry(act_head, struct dquot, dq_free);
860                 act_head = act_head->next;
861                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
862                 dqput(dquot);
863         }
864 }
865
866 static void remove_dquot_ref(struct super_block *sb, int type,
867                 struct list_head *tofree_head)
868 {
869         struct inode *inode;
870
871         spin_lock(&inode_lock);
872         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
873                 if (!IS_NOQUOTA(inode))
874                         remove_inode_dquot_ref(inode, type, tofree_head);
875         }
876         spin_unlock(&inode_lock);
877 }
878
879 /* Gather all references from inodes and drop them */
880 static void drop_dquot_ref(struct super_block *sb, int type)
881 {
882         LIST_HEAD(tofree_head);
883
884         if (sb->dq_op) {
885                 down_write(&sb_dqopt(sb)->dqptr_sem);
886                 remove_dquot_ref(sb, type, &tofree_head);
887                 up_write(&sb_dqopt(sb)->dqptr_sem);
888                 put_dquot_list(&tofree_head);
889         }
890 }
891
892 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
893 {
894         dquot->dq_dqb.dqb_curinodes += number;
895 }
896
897 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
898 {
899         dquot->dq_dqb.dqb_curspace += number;
900 }
901
902 static inline void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
903 {
904         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
905             dquot->dq_dqb.dqb_curinodes >= number)
906                 dquot->dq_dqb.dqb_curinodes -= number;
907         else
908                 dquot->dq_dqb.dqb_curinodes = 0;
909         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
910                 dquot->dq_dqb.dqb_itime = (time_t) 0;
911         clear_bit(DQ_INODES_B, &dquot->dq_flags);
912 }
913
914 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
915 {
916         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
917             dquot->dq_dqb.dqb_curspace >= number)
918                 dquot->dq_dqb.dqb_curspace -= number;
919         else
920                 dquot->dq_dqb.dqb_curspace = 0;
921         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
922                 dquot->dq_dqb.dqb_btime = (time_t) 0;
923         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
924 }
925
926 static int warning_issued(struct dquot *dquot, const int warntype)
927 {
928         int flag = (warntype == QUOTA_NL_BHARDWARN ||
929                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
930                 ((warntype == QUOTA_NL_IHARDWARN ||
931                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
932
933         if (!flag)
934                 return 0;
935         return test_and_set_bit(flag, &dquot->dq_flags);
936 }
937
938 #ifdef CONFIG_PRINT_QUOTA_WARNING
939 static int flag_print_warnings = 1;
940
941 static inline int need_print_warning(struct dquot *dquot)
942 {
943         if (!flag_print_warnings)
944                 return 0;
945
946         switch (dquot->dq_type) {
947                 case USRQUOTA:
948                         return current_fsuid() == dquot->dq_id;
949                 case GRPQUOTA:
950                         return in_group_p(dquot->dq_id);
951         }
952         return 0;
953 }
954
955 /* Print warning to user which exceeded quota */
956 static void print_warning(struct dquot *dquot, const int warntype)
957 {
958         char *msg = NULL;
959         struct tty_struct *tty;
960
961         if (warntype == QUOTA_NL_IHARDBELOW ||
962             warntype == QUOTA_NL_ISOFTBELOW ||
963             warntype == QUOTA_NL_BHARDBELOW ||
964             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
965                 return;
966
967         tty = get_current_tty();
968         if (!tty)
969                 return;
970         tty_write_message(tty, dquot->dq_sb->s_id);
971         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
972                 tty_write_message(tty, ": warning, ");
973         else
974                 tty_write_message(tty, ": write failed, ");
975         tty_write_message(tty, quotatypes[dquot->dq_type]);
976         switch (warntype) {
977                 case QUOTA_NL_IHARDWARN:
978                         msg = " file limit reached.\r\n";
979                         break;
980                 case QUOTA_NL_ISOFTLONGWARN:
981                         msg = " file quota exceeded too long.\r\n";
982                         break;
983                 case QUOTA_NL_ISOFTWARN:
984                         msg = " file quota exceeded.\r\n";
985                         break;
986                 case QUOTA_NL_BHARDWARN:
987                         msg = " block limit reached.\r\n";
988                         break;
989                 case QUOTA_NL_BSOFTLONGWARN:
990                         msg = " block quota exceeded too long.\r\n";
991                         break;
992                 case QUOTA_NL_BSOFTWARN:
993                         msg = " block quota exceeded.\r\n";
994                         break;
995         }
996         tty_write_message(tty, msg);
997         tty_kref_put(tty);
998 }
999 #endif
1000
1001 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
1002
1003 /* Netlink family structure for quota */
1004 static struct genl_family quota_genl_family = {
1005         .id = GENL_ID_GENERATE,
1006         .hdrsize = 0,
1007         .name = "VFS_DQUOT",
1008         .version = 1,
1009         .maxattr = QUOTA_NL_A_MAX,
1010 };
1011
1012 /* Send warning to userspace about user which exceeded quota */
1013 static void send_warning(const struct dquot *dquot, const char warntype)
1014 {
1015         static atomic_t seq;
1016         struct sk_buff *skb;
1017         void *msg_head;
1018         int ret;
1019         int msg_size = 4 * nla_total_size(sizeof(u32)) +
1020                        2 * nla_total_size(sizeof(u64));
1021
1022         /* We have to allocate using GFP_NOFS as we are called from a
1023          * filesystem performing write and thus further recursion into
1024          * the fs to free some data could cause deadlocks. */
1025         skb = genlmsg_new(msg_size, GFP_NOFS);
1026         if (!skb) {
1027                 printk(KERN_ERR
1028                   "VFS: Not enough memory to send quota warning.\n");
1029                 return;
1030         }
1031         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
1032                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
1033         if (!msg_head) {
1034                 printk(KERN_ERR
1035                   "VFS: Cannot store netlink header in quota warning.\n");
1036                 goto err_out;
1037         }
1038         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, dquot->dq_type);
1039         if (ret)
1040                 goto attr_err_out;
1041         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_id);
1042         if (ret)
1043                 goto attr_err_out;
1044         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
1045         if (ret)
1046                 goto attr_err_out;
1047         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR,
1048                 MAJOR(dquot->dq_sb->s_dev));
1049         if (ret)
1050                 goto attr_err_out;
1051         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,
1052                 MINOR(dquot->dq_sb->s_dev));
1053         if (ret)
1054                 goto attr_err_out;
1055         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
1056         if (ret)
1057                 goto attr_err_out;
1058         genlmsg_end(skb, msg_head);
1059
1060         ret = genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
1061         if (ret < 0 && ret != -ESRCH)
1062                 printk(KERN_ERR
1063                         "VFS: Failed to send notification message: %d\n", ret);
1064         return;
1065 attr_err_out:
1066         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
1067 err_out:
1068         kfree_skb(skb);
1069 }
1070 #endif
1071
1072 static inline void flush_warnings(struct dquot * const *dquots, char *warntype)
1073 {
1074         int i;
1075
1076         for (i = 0; i < MAXQUOTAS; i++)
1077                 if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN &&
1078                     !warning_issued(dquots[i], warntype[i])) {
1079 #ifdef CONFIG_PRINT_QUOTA_WARNING
1080                         print_warning(dquots[i], warntype[i]);
1081 #endif
1082 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
1083                         send_warning(dquots[i], warntype[i]);
1084 #endif
1085                 }
1086 }
1087
1088 static inline char ignore_hardlimit(struct dquot *dquot)
1089 {
1090         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
1091
1092         return capable(CAP_SYS_RESOURCE) &&
1093             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
1094 }
1095
1096 /* needs dq_data_lock */
1097 static int check_idq(struct dquot *dquot, qsize_t inodes, char *warntype)
1098 {
1099         *warntype = QUOTA_NL_NOWARN;
1100         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1101             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1102                 return QUOTA_OK;
1103
1104         if (dquot->dq_dqb.dqb_ihardlimit &&
1105            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
1106             !ignore_hardlimit(dquot)) {
1107                 *warntype = QUOTA_NL_IHARDWARN;
1108                 return NO_QUOTA;
1109         }
1110
1111         if (dquot->dq_dqb.dqb_isoftlimit &&
1112            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1113             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
1114             !ignore_hardlimit(dquot)) {
1115                 *warntype = QUOTA_NL_ISOFTLONGWARN;
1116                 return NO_QUOTA;
1117         }
1118
1119         if (dquot->dq_dqb.dqb_isoftlimit &&
1120            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1121             dquot->dq_dqb.dqb_itime == 0) {
1122                 *warntype = QUOTA_NL_ISOFTWARN;
1123                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1124         }
1125
1126         return QUOTA_OK;
1127 }
1128
1129 /* needs dq_data_lock */
1130 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
1131 {
1132         *warntype = QUOTA_NL_NOWARN;
1133         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1134             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1135                 return QUOTA_OK;
1136
1137         if (dquot->dq_dqb.dqb_bhardlimit &&
1138             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bhardlimit &&
1139             !ignore_hardlimit(dquot)) {
1140                 if (!prealloc)
1141                         *warntype = QUOTA_NL_BHARDWARN;
1142                 return NO_QUOTA;
1143         }
1144
1145         if (dquot->dq_dqb.dqb_bsoftlimit &&
1146             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bsoftlimit &&
1147             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
1148             !ignore_hardlimit(dquot)) {
1149                 if (!prealloc)
1150                         *warntype = QUOTA_NL_BSOFTLONGWARN;
1151                 return NO_QUOTA;
1152         }
1153
1154         if (dquot->dq_dqb.dqb_bsoftlimit &&
1155             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bsoftlimit &&
1156             dquot->dq_dqb.dqb_btime == 0) {
1157                 if (!prealloc) {
1158                         *warntype = QUOTA_NL_BSOFTWARN;
1159                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1160                 }
1161                 else
1162                         /*
1163                          * We don't allow preallocation to exceed softlimit so exceeding will
1164                          * be always printed
1165                          */
1166                         return NO_QUOTA;
1167         }
1168
1169         return QUOTA_OK;
1170 }
1171
1172 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1173 {
1174         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1175             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1176             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type))
1177                 return QUOTA_NL_NOWARN;
1178
1179         if (dquot->dq_dqb.dqb_curinodes - inodes <= dquot->dq_dqb.dqb_isoftlimit)
1180                 return QUOTA_NL_ISOFTBELOW;
1181         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1182             dquot->dq_dqb.dqb_curinodes - inodes < dquot->dq_dqb.dqb_ihardlimit)
1183                 return QUOTA_NL_IHARDBELOW;
1184         return QUOTA_NL_NOWARN;
1185 }
1186
1187 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1188 {
1189         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1190             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1191                 return QUOTA_NL_NOWARN;
1192
1193         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1194                 return QUOTA_NL_BSOFTBELOW;
1195         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1196             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1197                 return QUOTA_NL_BHARDBELOW;
1198         return QUOTA_NL_NOWARN;
1199 }
1200 /*
1201  *      Initialize quota pointers in inode
1202  *      We do things in a bit complicated way but by that we avoid calling
1203  *      dqget() and thus filesystem callbacks under dqptr_sem.
1204  */
1205 int dquot_initialize(struct inode *inode, int type)
1206 {
1207         unsigned int id = 0;
1208         int cnt, ret = 0;
1209         struct dquot *got[MAXQUOTAS] = { NODQUOT, NODQUOT };
1210         struct super_block *sb = inode->i_sb;
1211
1212         /* First test before acquiring mutex - solves deadlocks when we
1213          * re-enter the quota code and are already holding the mutex */
1214         if (IS_NOQUOTA(inode))
1215                 return 0;
1216
1217         /* First get references to structures we might need. */
1218         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1219                 if (type != -1 && cnt != type)
1220                         continue;
1221                 switch (cnt) {
1222                 case USRQUOTA:
1223                         id = inode->i_uid;
1224                         break;
1225                 case GRPQUOTA:
1226                         id = inode->i_gid;
1227                         break;
1228                 }
1229                 got[cnt] = dqget(sb, id, cnt);
1230         }
1231
1232         down_write(&sb_dqopt(sb)->dqptr_sem);
1233         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
1234         if (IS_NOQUOTA(inode))
1235                 goto out_err;
1236         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1237                 if (type != -1 && cnt != type)
1238                         continue;
1239                 /* Avoid races with quotaoff() */
1240                 if (!sb_has_quota_active(sb, cnt))
1241                         continue;
1242                 if (inode->i_dquot[cnt] == NODQUOT) {
1243                         inode->i_dquot[cnt] = got[cnt];
1244                         got[cnt] = NODQUOT;
1245                 }
1246         }
1247 out_err:
1248         up_write(&sb_dqopt(sb)->dqptr_sem);
1249         /* Drop unused references */
1250         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1251                 dqput(got[cnt]);
1252         return ret;
1253 }
1254
1255 /*
1256  *      Release all quotas referenced by inode
1257  */
1258 int dquot_drop(struct inode *inode)
1259 {
1260         int cnt;
1261         struct dquot *put[MAXQUOTAS];
1262
1263         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1264         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1265                 put[cnt] = inode->i_dquot[cnt];
1266                 inode->i_dquot[cnt] = NODQUOT;
1267         }
1268         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1269
1270         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1271                 dqput(put[cnt]);
1272         return 0;
1273 }
1274
1275 /* Wrapper to remove references to quota structures from inode */
1276 void vfs_dq_drop(struct inode *inode)
1277 {
1278         /* Here we can get arbitrary inode from clear_inode() so we have
1279          * to be careful. OTOH we don't need locking as quota operations
1280          * are allowed to change only at mount time */
1281         if (!IS_NOQUOTA(inode) && inode->i_sb && inode->i_sb->dq_op
1282             && inode->i_sb->dq_op->drop) {
1283                 int cnt;
1284                 /* Test before calling to rule out calls from proc and such
1285                  * where we are not allowed to block. Note that this is
1286                  * actually reliable test even without the lock - the caller
1287                  * must assure that nobody can come after the DQUOT_DROP and
1288                  * add quota pointers back anyway */
1289                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1290                         if (inode->i_dquot[cnt] != NODQUOT)
1291                                 break;
1292                 if (cnt < MAXQUOTAS)
1293                         inode->i_sb->dq_op->drop(inode);
1294         }
1295 }
1296
1297 /*
1298  * Following four functions update i_blocks+i_bytes fields and
1299  * quota information (together with appropriate checks)
1300  * NOTE: We absolutely rely on the fact that caller dirties
1301  * the inode (usually macros in quotaops.h care about this) and
1302  * holds a handle for the current transaction so that dquot write and
1303  * inode write go into the same transaction.
1304  */
1305
1306 /*
1307  * This operation can block, but only after everything is updated
1308  */
1309 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1310 {
1311         int cnt, ret = NO_QUOTA;
1312         char warntype[MAXQUOTAS];
1313
1314         /* First test before acquiring mutex - solves deadlocks when we
1315          * re-enter the quota code and are already holding the mutex */
1316         if (IS_NOQUOTA(inode)) {
1317 out_add:
1318                 inode_add_bytes(inode, number);
1319                 return QUOTA_OK;
1320         }
1321         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1322                 warntype[cnt] = QUOTA_NL_NOWARN;
1323
1324         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1325         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1326                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1327                 goto out_add;
1328         }
1329         spin_lock(&dq_data_lock);
1330         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1331                 if (inode->i_dquot[cnt] == NODQUOT)
1332                         continue;
1333                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1334                         goto warn_put_all;
1335         }
1336         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1337                 if (inode->i_dquot[cnt] == NODQUOT)
1338                         continue;
1339                 dquot_incr_space(inode->i_dquot[cnt], number);
1340         }
1341         inode_add_bytes(inode, number);
1342         ret = QUOTA_OK;
1343 warn_put_all:
1344         spin_unlock(&dq_data_lock);
1345         if (ret == QUOTA_OK)
1346                 /* Dirtify all the dquots - this can block when journalling */
1347                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1348                         if (inode->i_dquot[cnt])
1349                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1350         flush_warnings(inode->i_dquot, warntype);
1351         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1352         return ret;
1353 }
1354
1355 /*
1356  * This operation can block, but only after everything is updated
1357  */
1358 int dquot_alloc_inode(const struct inode *inode, qsize_t number)
1359 {
1360         int cnt, ret = NO_QUOTA;
1361         char warntype[MAXQUOTAS];
1362
1363         /* First test before acquiring mutex - solves deadlocks when we
1364          * re-enter the quota code and are already holding the mutex */
1365         if (IS_NOQUOTA(inode))
1366                 return QUOTA_OK;
1367         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1368                 warntype[cnt] = QUOTA_NL_NOWARN;
1369         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1370         if (IS_NOQUOTA(inode)) {
1371                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1372                 return QUOTA_OK;
1373         }
1374         spin_lock(&dq_data_lock);
1375         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1376                 if (inode->i_dquot[cnt] == NODQUOT)
1377                         continue;
1378                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1379                         goto warn_put_all;
1380         }
1381
1382         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1383                 if (inode->i_dquot[cnt] == NODQUOT)
1384                         continue;
1385                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1386         }
1387         ret = QUOTA_OK;
1388 warn_put_all:
1389         spin_unlock(&dq_data_lock);
1390         if (ret == QUOTA_OK)
1391                 /* Dirtify all the dquots - this can block when journalling */
1392                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1393                         if (inode->i_dquot[cnt])
1394                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1395         flush_warnings(inode->i_dquot, warntype);
1396         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1397         return ret;
1398 }
1399
1400 /*
1401  * This operation can block, but only after everything is updated
1402  */
1403 int dquot_free_space(struct inode *inode, qsize_t number)
1404 {
1405         unsigned int cnt;
1406         char warntype[MAXQUOTAS];
1407
1408         /* First test before acquiring mutex - solves deadlocks when we
1409          * re-enter the quota code and are already holding the mutex */
1410         if (IS_NOQUOTA(inode)) {
1411 out_sub:
1412                 inode_sub_bytes(inode, number);
1413                 return QUOTA_OK;
1414         }
1415
1416         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1417         /* Now recheck reliably when holding dqptr_sem */
1418         if (IS_NOQUOTA(inode)) {
1419                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1420                 goto out_sub;
1421         }
1422         spin_lock(&dq_data_lock);
1423         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1424                 if (inode->i_dquot[cnt] == NODQUOT)
1425                         continue;
1426                 warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
1427                 dquot_decr_space(inode->i_dquot[cnt], number);
1428         }
1429         inode_sub_bytes(inode, number);
1430         spin_unlock(&dq_data_lock);
1431         /* Dirtify all the dquots - this can block when journalling */
1432         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1433                 if (inode->i_dquot[cnt])
1434                         mark_dquot_dirty(inode->i_dquot[cnt]);
1435         flush_warnings(inode->i_dquot, warntype);
1436         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1437         return QUOTA_OK;
1438 }
1439
1440 /*
1441  * This operation can block, but only after everything is updated
1442  */
1443 int dquot_free_inode(const struct inode *inode, qsize_t number)
1444 {
1445         unsigned int cnt;
1446         char warntype[MAXQUOTAS];
1447
1448         /* First test before acquiring mutex - solves deadlocks when we
1449          * re-enter the quota code and are already holding the mutex */
1450         if (IS_NOQUOTA(inode))
1451                 return QUOTA_OK;
1452
1453         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1454         /* Now recheck reliably when holding dqptr_sem */
1455         if (IS_NOQUOTA(inode)) {
1456                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1457                 return QUOTA_OK;
1458         }
1459         spin_lock(&dq_data_lock);
1460         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1461                 if (inode->i_dquot[cnt] == NODQUOT)
1462                         continue;
1463                 warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
1464                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1465         }
1466         spin_unlock(&dq_data_lock);
1467         /* Dirtify all the dquots - this can block when journalling */
1468         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1469                 if (inode->i_dquot[cnt])
1470                         mark_dquot_dirty(inode->i_dquot[cnt]);
1471         flush_warnings(inode->i_dquot, warntype);
1472         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1473         return QUOTA_OK;
1474 }
1475
1476 /*
1477  * Transfer the number of inode and blocks from one diskquota to an other.
1478  *
1479  * This operation can block, but only after everything is updated
1480  * A transaction must be started when entering this function.
1481  */
1482 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1483 {
1484         qsize_t space;
1485         struct dquot *transfer_from[MAXQUOTAS];
1486         struct dquot *transfer_to[MAXQUOTAS];
1487         int cnt, ret = QUOTA_OK;
1488         int chuid = iattr->ia_valid & ATTR_UID && inode->i_uid != iattr->ia_uid,
1489             chgid = iattr->ia_valid & ATTR_GID && inode->i_gid != iattr->ia_gid;
1490         char warntype_to[MAXQUOTAS];
1491         char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
1492
1493         /* First test before acquiring mutex - solves deadlocks when we
1494          * re-enter the quota code and are already holding the mutex */
1495         if (IS_NOQUOTA(inode))
1496                 return QUOTA_OK;
1497         /* Initialize the arrays */
1498         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1499                 transfer_from[cnt] = NODQUOT;
1500                 transfer_to[cnt] = NODQUOT;
1501                 warntype_to[cnt] = QUOTA_NL_NOWARN;
1502                 switch (cnt) {
1503                         case USRQUOTA:
1504                                 if (!chuid)
1505                                         continue;
1506                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1507                                 break;
1508                         case GRPQUOTA:
1509                                 if (!chgid)
1510                                         continue;
1511                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1512                                 break;
1513                 }
1514         }
1515
1516         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1517         /* Now recheck reliably when holding dqptr_sem */
1518         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1519                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1520                 goto put_all;
1521         }
1522         spin_lock(&dq_data_lock);
1523         space = inode_get_bytes(inode);
1524         /* Build the transfer_from list and check the limits */
1525         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1526                 if (transfer_to[cnt] == NODQUOT)
1527                         continue;
1528                 transfer_from[cnt] = inode->i_dquot[cnt];
1529                 if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
1530                     NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
1531                     warntype_to + cnt) == NO_QUOTA)
1532                         goto over_quota;
1533         }
1534
1535         /*
1536          * Finally perform the needed transfer from transfer_from to transfer_to
1537          */
1538         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1539                 /*
1540                  * Skip changes for same uid or gid or for turned off quota-type.
1541                  */
1542                 if (transfer_to[cnt] == NODQUOT)
1543                         continue;
1544
1545                 /* Due to IO error we might not have transfer_from[] structure */
1546                 if (transfer_from[cnt]) {
1547                         warntype_from_inodes[cnt] =
1548                                 info_idq_free(transfer_from[cnt], 1);
1549                         warntype_from_space[cnt] =
1550                                 info_bdq_free(transfer_from[cnt], space);
1551                         dquot_decr_inodes(transfer_from[cnt], 1);
1552                         dquot_decr_space(transfer_from[cnt], space);
1553                 }
1554
1555                 dquot_incr_inodes(transfer_to[cnt], 1);
1556                 dquot_incr_space(transfer_to[cnt], space);
1557
1558                 inode->i_dquot[cnt] = transfer_to[cnt];
1559         }
1560         spin_unlock(&dq_data_lock);
1561         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1562
1563         /* Dirtify all the dquots - this can block when journalling */
1564         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1565                 if (transfer_from[cnt])
1566                         mark_dquot_dirty(transfer_from[cnt]);
1567                 if (transfer_to[cnt]) {
1568                         mark_dquot_dirty(transfer_to[cnt]);
1569                         /* The reference we got is transferred to the inode */
1570                         transfer_to[cnt] = NODQUOT;
1571                 }
1572         }
1573 warn_put_all:
1574         flush_warnings(transfer_to, warntype_to);
1575         flush_warnings(transfer_from, warntype_from_inodes);
1576         flush_warnings(transfer_from, warntype_from_space);
1577 put_all:
1578         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1579                 dqput(transfer_from[cnt]);
1580                 dqput(transfer_to[cnt]);
1581         }
1582         return ret;
1583 over_quota:
1584         spin_unlock(&dq_data_lock);
1585         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1586         /* Clear dquot pointers we don't want to dqput() */
1587         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1588                 transfer_from[cnt] = NODQUOT;
1589         ret = NO_QUOTA;
1590         goto warn_put_all;
1591 }
1592
1593 /* Wrapper for transferring ownership of an inode */
1594 int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
1595 {
1596         if (sb_any_quota_active(inode->i_sb) && !IS_NOQUOTA(inode)) {
1597                 vfs_dq_init(inode);
1598                 if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
1599                         return 1;
1600         }
1601         return 0;
1602 }
1603
1604
1605 /*
1606  * Write info of quota file to disk
1607  */
1608 int dquot_commit_info(struct super_block *sb, int type)
1609 {
1610         int ret;
1611         struct quota_info *dqopt = sb_dqopt(sb);
1612
1613         mutex_lock(&dqopt->dqio_mutex);
1614         ret = dqopt->ops[type]->write_file_info(sb, type);
1615         mutex_unlock(&dqopt->dqio_mutex);
1616         return ret;
1617 }
1618
1619 /*
1620  * Definitions of diskquota operations.
1621  */
1622 struct dquot_operations dquot_operations = {
1623         .initialize     = dquot_initialize,
1624         .drop           = dquot_drop,
1625         .alloc_space    = dquot_alloc_space,
1626         .alloc_inode    = dquot_alloc_inode,
1627         .free_space     = dquot_free_space,
1628         .free_inode     = dquot_free_inode,
1629         .transfer       = dquot_transfer,
1630         .write_dquot    = dquot_commit,
1631         .acquire_dquot  = dquot_acquire,
1632         .release_dquot  = dquot_release,
1633         .mark_dirty     = dquot_mark_dquot_dirty,
1634         .write_info     = dquot_commit_info,
1635         .alloc_dquot    = dquot_alloc,
1636         .destroy_dquot  = dquot_destroy,
1637 };
1638
1639 /*
1640  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1641  */
1642 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
1643 {
1644         int cnt, ret = 0;
1645         struct quota_info *dqopt = sb_dqopt(sb);
1646         struct inode *toputinode[MAXQUOTAS];
1647
1648         /* Cannot turn off usage accounting without turning off limits, or
1649          * suspend quotas and simultaneously turn quotas off. */
1650         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
1651             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
1652             DQUOT_USAGE_ENABLED)))
1653                 return -EINVAL;
1654
1655         /* We need to serialize quota_off() for device */
1656         mutex_lock(&dqopt->dqonoff_mutex);
1657
1658         /*
1659          * Skip everything if there's nothing to do. We have to do this because
1660          * sometimes we are called when fill_super() failed and calling
1661          * sync_fs() in such cases does no good.
1662          */
1663         if (!sb_any_quota_loaded(sb)) {
1664                 mutex_unlock(&dqopt->dqonoff_mutex);
1665                 return 0;
1666         }
1667         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1668                 toputinode[cnt] = NULL;
1669                 if (type != -1 && cnt != type)
1670                         continue;
1671                 if (!sb_has_quota_loaded(sb, cnt))
1672                         continue;
1673
1674                 if (flags & DQUOT_SUSPENDED) {
1675                         spin_lock(&dq_state_lock);
1676                         dqopt->flags |=
1677                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
1678                         spin_unlock(&dq_state_lock);
1679                 } else {
1680                         spin_lock(&dq_state_lock);
1681                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
1682                         /* Turning off suspended quotas? */
1683                         if (!sb_has_quota_loaded(sb, cnt) &&
1684                             sb_has_quota_suspended(sb, cnt)) {
1685                                 dqopt->flags &= ~dquot_state_flag(
1686                                                         DQUOT_SUSPENDED, cnt);
1687                                 spin_unlock(&dq_state_lock);
1688                                 iput(dqopt->files[cnt]);
1689                                 dqopt->files[cnt] = NULL;
1690                                 continue;
1691                         }
1692                         spin_unlock(&dq_state_lock);
1693                 }
1694
1695                 /* We still have to keep quota loaded? */
1696                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
1697                         continue;
1698
1699                 /* Note: these are blocking operations */
1700                 drop_dquot_ref(sb, cnt);
1701                 invalidate_dquots(sb, cnt);
1702                 /*
1703                  * Now all dquots should be invalidated, all writes done so we should be only
1704                  * users of the info. No locks needed.
1705                  */
1706                 if (info_dirty(&dqopt->info[cnt]))
1707                         sb->dq_op->write_info(sb, cnt);
1708                 if (dqopt->ops[cnt]->free_file_info)
1709                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1710                 put_quota_format(dqopt->info[cnt].dqi_format);
1711
1712                 toputinode[cnt] = dqopt->files[cnt];
1713                 if (!sb_has_quota_loaded(sb, cnt))
1714                         dqopt->files[cnt] = NULL;
1715                 dqopt->info[cnt].dqi_flags = 0;
1716                 dqopt->info[cnt].dqi_igrace = 0;
1717                 dqopt->info[cnt].dqi_bgrace = 0;
1718                 dqopt->ops[cnt] = NULL;
1719         }
1720         mutex_unlock(&dqopt->dqonoff_mutex);
1721
1722         /* Skip syncing and setting flags if quota files are hidden */
1723         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
1724                 goto put_inodes;
1725
1726         /* Sync the superblock so that buffers with quota data are written to
1727          * disk (and so userspace sees correct data afterwards). */
1728         if (sb->s_op->sync_fs)
1729                 sb->s_op->sync_fs(sb, 1);
1730         sync_blockdev(sb->s_bdev);
1731         /* Now the quota files are just ordinary files and we can set the
1732          * inode flags back. Moreover we discard the pagecache so that
1733          * userspace sees the writes we did bypassing the pagecache. We
1734          * must also discard the blockdev buffers so that we see the
1735          * changes done by userspace on the next quotaon() */
1736         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1737                 if (toputinode[cnt]) {
1738                         mutex_lock(&dqopt->dqonoff_mutex);
1739                         /* If quota was reenabled in the meantime, we have
1740                          * nothing to do */
1741                         if (!sb_has_quota_loaded(sb, cnt)) {
1742                                 mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
1743                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1744                                   S_NOATIME | S_NOQUOTA);
1745                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1746                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1747                                 mark_inode_dirty(toputinode[cnt]);
1748                         }
1749                         mutex_unlock(&dqopt->dqonoff_mutex);
1750                 }
1751         if (sb->s_bdev)
1752                 invalidate_bdev(sb->s_bdev);
1753 put_inodes:
1754         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1755                 if (toputinode[cnt]) {
1756                         /* On remount RO, we keep the inode pointer so that we
1757                          * can reenable quota on the subsequent remount RW. We
1758                          * have to check 'flags' variable and not use sb_has_
1759                          * function because another quotaon / quotaoff could
1760                          * change global state before we got here. We refuse
1761                          * to suspend quotas when there is pending delete on
1762                          * the quota file... */
1763                         if (!(flags & DQUOT_SUSPENDED))
1764                                 iput(toputinode[cnt]);
1765                         else if (!toputinode[cnt]->i_nlink)
1766                                 ret = -EBUSY;
1767                 }
1768         return ret;
1769 }
1770
1771 int vfs_quota_off(struct super_block *sb, int type, int remount)
1772 {
1773         return vfs_quota_disable(sb, type, remount ? DQUOT_SUSPENDED :
1774                                  (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED));
1775 }
1776
1777 /*
1778  *      Turn quotas on on a device
1779  */
1780
1781 /*
1782  * Helper function to turn quotas on when we already have the inode of
1783  * quota file and no quota information is loaded.
1784  */
1785 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
1786         unsigned int flags)
1787 {
1788         struct quota_format_type *fmt = find_quota_format(format_id);
1789         struct super_block *sb = inode->i_sb;
1790         struct quota_info *dqopt = sb_dqopt(sb);
1791         int error;
1792         int oldflags = -1;
1793
1794         if (!fmt)
1795                 return -ESRCH;
1796         if (!S_ISREG(inode->i_mode)) {
1797                 error = -EACCES;
1798                 goto out_fmt;
1799         }
1800         if (IS_RDONLY(inode)) {
1801                 error = -EROFS;
1802                 goto out_fmt;
1803         }
1804         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1805                 error = -EINVAL;
1806                 goto out_fmt;
1807         }
1808         /* Usage always has to be set... */
1809         if (!(flags & DQUOT_USAGE_ENABLED)) {
1810                 error = -EINVAL;
1811                 goto out_fmt;
1812         }
1813
1814         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1815                 /* As we bypass the pagecache we must now flush the inode so
1816                  * that we see all the changes from userspace... */
1817                 write_inode_now(inode, 1);
1818                 /* And now flush the block cache so that kernel sees the
1819                  * changes */
1820                 invalidate_bdev(sb->s_bdev);
1821         }
1822         mutex_lock(&inode->i_mutex);
1823         mutex_lock(&dqopt->dqonoff_mutex);
1824         if (sb_has_quota_loaded(sb, type)) {
1825                 error = -EBUSY;
1826                 goto out_lock;
1827         }
1828
1829         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1830                 /* We don't want quota and atime on quota files (deadlocks
1831                  * possible) Also nobody should write to the file - we use
1832                  * special IO operations which ignore the immutable bit. */
1833                 down_write(&dqopt->dqptr_sem);
1834                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1835                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1836                 up_write(&dqopt->dqptr_sem);
1837                 sb->dq_op->drop(inode);
1838         }
1839
1840         error = -EIO;
1841         dqopt->files[type] = igrab(inode);
1842         if (!dqopt->files[type])
1843                 goto out_lock;
1844         error = -EINVAL;
1845         if (!fmt->qf_ops->check_quota_file(sb, type))
1846                 goto out_file_init;
1847
1848         dqopt->ops[type] = fmt->qf_ops;
1849         dqopt->info[type].dqi_format = fmt;
1850         dqopt->info[type].dqi_fmt_id = format_id;
1851         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1852         mutex_lock(&dqopt->dqio_mutex);
1853         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1854                 mutex_unlock(&dqopt->dqio_mutex);
1855                 goto out_file_init;
1856         }
1857         mutex_unlock(&dqopt->dqio_mutex);
1858         mutex_unlock(&inode->i_mutex);
1859         spin_lock(&dq_state_lock);
1860         dqopt->flags |= dquot_state_flag(flags, type);
1861         spin_unlock(&dq_state_lock);
1862
1863         add_dquot_ref(sb, type);
1864         mutex_unlock(&dqopt->dqonoff_mutex);
1865
1866         return 0;
1867
1868 out_file_init:
1869         dqopt->files[type] = NULL;
1870         iput(inode);
1871 out_lock:
1872         mutex_unlock(&dqopt->dqonoff_mutex);
1873         if (oldflags != -1) {
1874                 down_write(&dqopt->dqptr_sem);
1875                 /* Set the flags back (in the case of accidental quotaon()
1876                  * on a wrong file we don't want to mess up the flags) */
1877                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1878                 inode->i_flags |= oldflags;
1879                 up_write(&dqopt->dqptr_sem);
1880         }
1881         mutex_unlock(&inode->i_mutex);
1882 out_fmt:
1883         put_quota_format(fmt);
1884
1885         return error; 
1886 }
1887
1888 /* Reenable quotas on remount RW */
1889 static int vfs_quota_on_remount(struct super_block *sb, int type)
1890 {
1891         struct quota_info *dqopt = sb_dqopt(sb);
1892         struct inode *inode;
1893         int ret;
1894         unsigned int flags;
1895
1896         mutex_lock(&dqopt->dqonoff_mutex);
1897         if (!sb_has_quota_suspended(sb, type)) {
1898                 mutex_unlock(&dqopt->dqonoff_mutex);
1899                 return 0;
1900         }
1901         inode = dqopt->files[type];
1902         dqopt->files[type] = NULL;
1903         spin_lock(&dq_state_lock);
1904         flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
1905                                                 DQUOT_LIMITS_ENABLED, type);
1906         dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, type);
1907         spin_unlock(&dq_state_lock);
1908         mutex_unlock(&dqopt->dqonoff_mutex);
1909
1910         flags = dquot_generic_flag(flags, type);
1911         ret = vfs_load_quota_inode(inode, type, dqopt->info[type].dqi_fmt_id,
1912                                    flags);
1913         iput(inode);
1914
1915         return ret;
1916 }
1917
1918 int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
1919                       struct path *path)
1920 {
1921         int error = security_quota_on(path->dentry);
1922         if (error)
1923                 return error;
1924         /* Quota file not on the same filesystem? */
1925         if (path->mnt->mnt_sb != sb)
1926                 error = -EXDEV;
1927         else
1928                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
1929                                              format_id, DQUOT_USAGE_ENABLED |
1930                                              DQUOT_LIMITS_ENABLED);
1931         return error;
1932 }
1933
1934 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
1935                  int remount)
1936 {
1937         struct path path;
1938         int error;
1939
1940         if (remount)
1941                 return vfs_quota_on_remount(sb, type);
1942
1943         error = kern_path(name, LOOKUP_FOLLOW, &path);
1944         if (!error) {
1945                 error = vfs_quota_on_path(sb, type, format_id, &path);
1946                 path_put(&path);
1947         }
1948         return error;
1949 }
1950
1951 /*
1952  * More powerful function for turning on quotas allowing setting
1953  * of individual quota flags
1954  */
1955 int vfs_quota_enable(struct inode *inode, int type, int format_id,
1956                 unsigned int flags)
1957 {
1958         int ret = 0;
1959         struct super_block *sb = inode->i_sb;
1960         struct quota_info *dqopt = sb_dqopt(sb);
1961
1962         /* Just unsuspend quotas? */
1963         if (flags & DQUOT_SUSPENDED)
1964                 return vfs_quota_on_remount(sb, type);
1965         if (!flags)
1966                 return 0;
1967         /* Just updating flags needed? */
1968         if (sb_has_quota_loaded(sb, type)) {
1969                 mutex_lock(&dqopt->dqonoff_mutex);
1970                 /* Now do a reliable test... */
1971                 if (!sb_has_quota_loaded(sb, type)) {
1972                         mutex_unlock(&dqopt->dqonoff_mutex);
1973                         goto load_quota;
1974                 }
1975                 if (flags & DQUOT_USAGE_ENABLED &&
1976                     sb_has_quota_usage_enabled(sb, type)) {
1977                         ret = -EBUSY;
1978                         goto out_lock;
1979                 }
1980                 if (flags & DQUOT_LIMITS_ENABLED &&
1981                     sb_has_quota_limits_enabled(sb, type)) {
1982                         ret = -EBUSY;
1983                         goto out_lock;
1984                 }
1985                 spin_lock(&dq_state_lock);
1986                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
1987                 spin_unlock(&dq_state_lock);
1988 out_lock:
1989                 mutex_unlock(&dqopt->dqonoff_mutex);
1990                 return ret;
1991         }
1992
1993 load_quota:
1994         return vfs_load_quota_inode(inode, type, format_id, flags);
1995 }
1996
1997 /*
1998  * This function is used when filesystem needs to initialize quotas
1999  * during mount time.
2000  */
2001 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
2002                 int format_id, int type)
2003 {
2004         struct dentry *dentry;
2005         int error;
2006
2007         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2008         if (IS_ERR(dentry))
2009                 return PTR_ERR(dentry);
2010
2011         if (!dentry->d_inode) {
2012                 error = -ENOENT;
2013                 goto out;
2014         }
2015
2016         error = security_quota_on(dentry);
2017         if (!error)
2018                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2019                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2020
2021 out:
2022         dput(dentry);
2023         return error;
2024 }
2025
2026 /* Wrapper to turn on quotas when remounting rw */
2027 int vfs_dq_quota_on_remount(struct super_block *sb)
2028 {
2029         int cnt;
2030         int ret = 0, err;
2031
2032         if (!sb->s_qcop || !sb->s_qcop->quota_on)
2033                 return -ENOSYS;
2034         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2035                 err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
2036                 if (err < 0 && !ret)
2037                         ret = err;
2038         }
2039         return ret;
2040 }
2041
2042 static inline qsize_t qbtos(qsize_t blocks)
2043 {
2044         return blocks << QIF_DQBLKSIZE_BITS;
2045 }
2046
2047 static inline qsize_t stoqb(qsize_t space)
2048 {
2049         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2050 }
2051
2052 /* Generic routine for getting common part of quota structure */
2053 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
2054 {
2055         struct mem_dqblk *dm = &dquot->dq_dqb;
2056
2057         spin_lock(&dq_data_lock);
2058         di->dqb_bhardlimit = stoqb(dm->dqb_bhardlimit);
2059         di->dqb_bsoftlimit = stoqb(dm->dqb_bsoftlimit);
2060         di->dqb_curspace = dm->dqb_curspace;
2061         di->dqb_ihardlimit = dm->dqb_ihardlimit;
2062         di->dqb_isoftlimit = dm->dqb_isoftlimit;
2063         di->dqb_curinodes = dm->dqb_curinodes;
2064         di->dqb_btime = dm->dqb_btime;
2065         di->dqb_itime = dm->dqb_itime;
2066         di->dqb_valid = QIF_ALL;
2067         spin_unlock(&dq_data_lock);
2068 }
2069
2070 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
2071 {
2072         struct dquot *dquot;
2073
2074         dquot = dqget(sb, id, type);
2075         if (dquot == NODQUOT)
2076                 return -ESRCH;
2077         do_get_dqblk(dquot, di);
2078         dqput(dquot);
2079
2080         return 0;
2081 }
2082
2083 /* Generic routine for setting common part of quota structure */
2084 static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
2085 {
2086         struct mem_dqblk *dm = &dquot->dq_dqb;
2087         int check_blim = 0, check_ilim = 0;
2088         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
2089
2090         if ((di->dqb_valid & QIF_BLIMITS &&
2091              (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
2092               di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
2093             (di->dqb_valid & QIF_ILIMITS &&
2094              (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
2095               di->dqb_isoftlimit > dqi->dqi_maxilimit)))
2096                 return -ERANGE;
2097
2098         spin_lock(&dq_data_lock);
2099         if (di->dqb_valid & QIF_SPACE) {
2100                 dm->dqb_curspace = di->dqb_curspace;
2101                 check_blim = 1;
2102                 __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2103         }
2104         if (di->dqb_valid & QIF_BLIMITS) {
2105                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
2106                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
2107                 check_blim = 1;
2108                 __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2109         }
2110         if (di->dqb_valid & QIF_INODES) {
2111                 dm->dqb_curinodes = di->dqb_curinodes;
2112                 check_ilim = 1;
2113                 __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2114         }
2115         if (di->dqb_valid & QIF_ILIMITS) {
2116                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
2117                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
2118                 check_ilim = 1;
2119                 __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2120         }
2121         if (di->dqb_valid & QIF_BTIME) {
2122                 dm->dqb_btime = di->dqb_btime;
2123                 check_blim = 1;
2124                 __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2125         }
2126         if (di->dqb_valid & QIF_ITIME) {
2127                 dm->dqb_itime = di->dqb_itime;
2128                 check_ilim = 1;
2129                 __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2130         }
2131
2132         if (check_blim) {
2133                 if (!dm->dqb_bsoftlimit || dm->dqb_curspace < dm->dqb_bsoftlimit) {
2134                         dm->dqb_btime = 0;
2135                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2136                 }
2137                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
2138                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2139         }
2140         if (check_ilim) {
2141                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
2142                         dm->dqb_itime = 0;
2143                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2144                 }
2145                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
2146                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2147         }
2148         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
2149                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2150         else
2151                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2152         spin_unlock(&dq_data_lock);
2153         mark_dquot_dirty(dquot);
2154
2155         return 0;
2156 }
2157
2158 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
2159 {
2160         struct dquot *dquot;
2161         int rc;
2162
2163         dquot = dqget(sb, id, type);
2164         if (!dquot) {
2165                 rc = -ESRCH;
2166                 goto out;
2167         }
2168         rc = do_set_dqblk(dquot, di);
2169         dqput(dquot);
2170 out:
2171         return rc;
2172 }
2173
2174 /* Generic routine for getting common part of quota file information */
2175 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2176 {
2177         struct mem_dqinfo *mi;
2178   
2179         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2180         if (!sb_has_quota_active(sb, type)) {
2181                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2182                 return -ESRCH;
2183         }
2184         mi = sb_dqopt(sb)->info + type;
2185         spin_lock(&dq_data_lock);
2186         ii->dqi_bgrace = mi->dqi_bgrace;
2187         ii->dqi_igrace = mi->dqi_igrace;
2188         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
2189         ii->dqi_valid = IIF_ALL;
2190         spin_unlock(&dq_data_lock);
2191         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2192         return 0;
2193 }
2194
2195 /* Generic routine for setting common part of quota file information */
2196 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2197 {
2198         struct mem_dqinfo *mi;
2199         int err = 0;
2200
2201         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2202         if (!sb_has_quota_active(sb, type)) {
2203                 err = -ESRCH;
2204                 goto out;
2205         }
2206         mi = sb_dqopt(sb)->info + type;
2207         spin_lock(&dq_data_lock);
2208         if (ii->dqi_valid & IIF_BGRACE)
2209                 mi->dqi_bgrace = ii->dqi_bgrace;
2210         if (ii->dqi_valid & IIF_IGRACE)
2211                 mi->dqi_igrace = ii->dqi_igrace;
2212         if (ii->dqi_valid & IIF_FLAGS)
2213                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
2214         spin_unlock(&dq_data_lock);
2215         mark_info_dirty(sb, type);
2216         /* Force write to disk */
2217         sb->dq_op->write_info(sb, type);
2218 out:
2219         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2220         return err;
2221 }
2222
2223 struct quotactl_ops vfs_quotactl_ops = {
2224         .quota_on       = vfs_quota_on,
2225         .quota_off      = vfs_quota_off,
2226         .quota_sync     = vfs_quota_sync,
2227         .get_info       = vfs_get_dqinfo,
2228         .set_info       = vfs_set_dqinfo,
2229         .get_dqblk      = vfs_get_dqblk,
2230         .set_dqblk      = vfs_set_dqblk
2231 };
2232
2233 static ctl_table fs_dqstats_table[] = {
2234         {
2235                 .ctl_name       = FS_DQ_LOOKUPS,
2236                 .procname       = "lookups",
2237                 .data           = &dqstats.lookups,
2238                 .maxlen         = sizeof(int),
2239                 .mode           = 0444,
2240                 .proc_handler   = &proc_dointvec,
2241         },
2242         {
2243                 .ctl_name       = FS_DQ_DROPS,
2244                 .procname       = "drops",
2245                 .data           = &dqstats.drops,
2246                 .maxlen         = sizeof(int),
2247                 .mode           = 0444,
2248                 .proc_handler   = &proc_dointvec,
2249         },
2250         {
2251                 .ctl_name       = FS_DQ_READS,
2252                 .procname       = "reads",
2253                 .data           = &dqstats.reads,
2254                 .maxlen         = sizeof(int),
2255                 .mode           = 0444,
2256                 .proc_handler   = &proc_dointvec,
2257         },
2258         {
2259                 .ctl_name       = FS_DQ_WRITES,
2260                 .procname       = "writes",
2261                 .data           = &dqstats.writes,
2262                 .maxlen         = sizeof(int),
2263                 .mode           = 0444,
2264                 .proc_handler   = &proc_dointvec,
2265         },
2266         {
2267                 .ctl_name       = FS_DQ_CACHE_HITS,
2268                 .procname       = "cache_hits",
2269                 .data           = &dqstats.cache_hits,
2270                 .maxlen         = sizeof(int),
2271                 .mode           = 0444,
2272                 .proc_handler   = &proc_dointvec,
2273         },
2274         {
2275                 .ctl_name       = FS_DQ_ALLOCATED,
2276                 .procname       = "allocated_dquots",
2277                 .data           = &dqstats.allocated_dquots,
2278                 .maxlen         = sizeof(int),
2279                 .mode           = 0444,
2280                 .proc_handler   = &proc_dointvec,
2281         },
2282         {
2283                 .ctl_name       = FS_DQ_FREE,
2284                 .procname       = "free_dquots",
2285                 .data           = &dqstats.free_dquots,
2286                 .maxlen         = sizeof(int),
2287                 .mode           = 0444,
2288                 .proc_handler   = &proc_dointvec,
2289         },
2290         {
2291                 .ctl_name       = FS_DQ_SYNCS,
2292                 .procname       = "syncs",
2293                 .data           = &dqstats.syncs,
2294                 .maxlen         = sizeof(int),
2295                 .mode           = 0444,
2296                 .proc_handler   = &proc_dointvec,
2297         },
2298 #ifdef CONFIG_PRINT_QUOTA_WARNING
2299         {
2300                 .ctl_name       = FS_DQ_WARNINGS,
2301                 .procname       = "warnings",
2302                 .data           = &flag_print_warnings,
2303                 .maxlen         = sizeof(int),
2304                 .mode           = 0644,
2305                 .proc_handler   = &proc_dointvec,
2306         },
2307 #endif
2308         { .ctl_name = 0 },
2309 };
2310
2311 static ctl_table fs_table[] = {
2312         {
2313                 .ctl_name       = FS_DQSTATS,
2314                 .procname       = "quota",
2315                 .mode           = 0555,
2316                 .child          = fs_dqstats_table,
2317         },
2318         { .ctl_name = 0 },
2319 };
2320
2321 static ctl_table sys_table[] = {
2322         {
2323                 .ctl_name       = CTL_FS,
2324                 .procname       = "fs",
2325                 .mode           = 0555,
2326                 .child          = fs_table,
2327         },
2328         { .ctl_name = 0 },
2329 };
2330
2331 static int __init dquot_init(void)
2332 {
2333         int i;
2334         unsigned long nr_hash, order;
2335
2336         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2337
2338         register_sysctl_table(sys_table);
2339
2340         dquot_cachep = kmem_cache_create("dquot",
2341                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2342                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2343                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2344                         NULL);
2345
2346         order = 0;
2347         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2348         if (!dquot_hash)
2349                 panic("Cannot create dquot hash table");
2350
2351         /* Find power-of-two hlist_heads which can fit into allocation */
2352         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2353         dq_hash_bits = 0;
2354         do {
2355                 dq_hash_bits++;
2356         } while (nr_hash >> dq_hash_bits);
2357         dq_hash_bits--;
2358
2359         nr_hash = 1UL << dq_hash_bits;
2360         dq_hash_mask = nr_hash - 1;
2361         for (i = 0; i < nr_hash; i++)
2362                 INIT_HLIST_HEAD(dquot_hash + i);
2363
2364         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2365                         nr_hash, order, (PAGE_SIZE << order));
2366
2367         register_shrinker(&dqcache_shrinker);
2368
2369 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
2370         if (genl_register_family(&quota_genl_family) != 0)
2371                 printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
2372 #endif
2373
2374         return 0;
2375 }
2376 module_init(dquot_init);
2377
2378 EXPORT_SYMBOL(register_quota_format);
2379 EXPORT_SYMBOL(unregister_quota_format);
2380 EXPORT_SYMBOL(dqstats);
2381 EXPORT_SYMBOL(dq_data_lock);
2382 EXPORT_SYMBOL(vfs_quota_enable);
2383 EXPORT_SYMBOL(vfs_quota_on);
2384 EXPORT_SYMBOL(vfs_quota_on_path);
2385 EXPORT_SYMBOL(vfs_quota_on_mount);
2386 EXPORT_SYMBOL(vfs_quota_disable);
2387 EXPORT_SYMBOL(vfs_quota_off);
2388 EXPORT_SYMBOL(dquot_scan_active);
2389 EXPORT_SYMBOL(vfs_quota_sync);
2390 EXPORT_SYMBOL(vfs_get_dqinfo);
2391 EXPORT_SYMBOL(vfs_set_dqinfo);
2392 EXPORT_SYMBOL(vfs_get_dqblk);
2393 EXPORT_SYMBOL(vfs_set_dqblk);
2394 EXPORT_SYMBOL(dquot_commit);
2395 EXPORT_SYMBOL(dquot_commit_info);
2396 EXPORT_SYMBOL(dquot_acquire);
2397 EXPORT_SYMBOL(dquot_release);
2398 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
2399 EXPORT_SYMBOL(dquot_initialize);
2400 EXPORT_SYMBOL(dquot_drop);
2401 EXPORT_SYMBOL(vfs_dq_drop);
2402 EXPORT_SYMBOL(dqget);
2403 EXPORT_SYMBOL(dqput);
2404 EXPORT_SYMBOL(dquot_alloc_space);
2405 EXPORT_SYMBOL(dquot_alloc_inode);
2406 EXPORT_SYMBOL(dquot_free_space);
2407 EXPORT_SYMBOL(dquot_free_inode);
2408 EXPORT_SYMBOL(dquot_transfer);
2409 EXPORT_SYMBOL(vfs_dq_transfer);
2410 EXPORT_SYMBOL(vfs_dq_quota_on_remount);