afa06a893468571785ca335a32a6bd89eafda4a0
[linux-2.6.git] / 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  * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
13  * 
14  * Author:      Marco van Wieringen <mvw@planets.elm.net>
15  *
16  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
17  *
18  *              Revised list management to avoid races
19  *              -- Bill Hawes, <whawes@star.net>, 9/98
20  *
21  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
22  *              As the consequence the locking was moved from dquot_decr_...(),
23  *              dquot_incr_...() to calling functions.
24  *              invalidate_dquots() now writes modified dquots.
25  *              Serialized quota_off() and quota_on() for mount point.
26  *              Fixed a few bugs in grow_dquots().
27  *              Fixed deadlock in write_dquot() - we no longer account quotas on
28  *              quota files
29  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
30  *              add_dquot_ref() restarts after blocking
31  *              Added check for bogus uid and fixed check for group in quotactl.
32  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
33  *
34  *              Used struct list_head instead of own list struct
35  *              Invalidation of referenced dquots is no longer possible
36  *              Improved free_dquots list management
37  *              Quota and i_blocks are now updated in one place to avoid races
38  *              Warnings are now delayed so we won't block in critical section
39  *              Write updated not to require dquot lock
40  *              Jan Kara, <jack@suse.cz>, 9/2000
41  *
42  *              Added dynamic quota structure allocation
43  *              Jan Kara <jack@suse.cz> 12/2000
44  *
45  *              Rewritten quota interface. Implemented new quota format and
46  *              formats registering.
47  *              Jan Kara, <jack@suse.cz>, 2001,2002
48  *
49  *              New SMP locking.
50  *              Jan Kara, <jack@suse.cz>, 10/2002
51  *
52  *              Added journalled quota support, fix lock inversion problems
53  *              Jan Kara, <jack@suse.cz>, 2003,2004
54  *
55  * (C) Copyright 1994 - 1997 Marco van Wieringen 
56  */
57
58 #include <linux/errno.h>
59 #include <linux/kernel.h>
60 #include <linux/fs.h>
61 #include <linux/mount.h>
62 #include <linux/mm.h>
63 #include <linux/time.h>
64 #include <linux/types.h>
65 #include <linux/string.h>
66 #include <linux/fcntl.h>
67 #include <linux/stat.h>
68 #include <linux/tty.h>
69 #include <linux/file.h>
70 #include <linux/slab.h>
71 #include <linux/sysctl.h>
72 #include <linux/smp_lock.h>
73 #include <linux/init.h>
74 #include <linux/module.h>
75 #include <linux/proc_fs.h>
76 #include <linux/security.h>
77 #include <linux/kmod.h>
78 #include <linux/namei.h>
79 #include <linux/buffer_head.h>
80 #include <linux/quotaops.h>
81
82 #include <asm/uaccess.h>
83
84 #define __DQUOT_PARANOIA
85
86 /*
87  * There are two quota SMP locks. dq_list_lock protects all lists with quotas
88  * and quota formats and also dqstats structure containing statistics about the
89  * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
90  * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
91  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
92  * in inode_add_bytes() and inode_sub_bytes().
93  *
94  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
95  *
96  * Note that some things (eg. sb pointer, type, id) doesn't change during
97  * the life of the dquot structure and so needn't to be protected by a lock
98  *
99  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
100  * operation is just reading pointers from inode (or not using them at all) the
101  * read lock is enough. If pointers are altered function must hold write lock
102  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
103  * for altering the flag i_sem is also needed).  If operation is holding
104  * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
105  * dqonoff_sem.
106  * This locking assures that:
107  *   a) update/access to dquot pointers in inode is serialized
108  *   b) everyone is guarded against invalidate_dquots()
109  *
110  * Each dquot has its dq_lock semaphore. Locked dquots might not be referenced
111  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
112  * Currently dquot is locked only when it is being read to memory (or space for
113  * it is being allocated) on the first dqget() and when it is being released on
114  * the last dqput(). The allocation and release oparations are serialized by
115  * the dq_lock and by checking the use count in dquot_release().  Write
116  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
117  * spinlock to internal buffers before writing.
118  *
119  * Lock ordering (including related VFS locks) is the following:
120  *   i_sem > dqonoff_sem > iprune_sem > journal_lock > dqptr_sem >
121  *   > dquot->dq_lock > dqio_sem
122  * i_sem on quota files is special (it's below dqio_sem)
123  */
124
125 static DEFINE_SPINLOCK(dq_list_lock);
126 DEFINE_SPINLOCK(dq_data_lock);
127
128 static char *quotatypes[] = INITQFNAMES;
129 static struct quota_format_type *quota_formats; /* List of registered formats */
130 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
131
132 /* SLAB cache for dquot structures */
133 static kmem_cache_t *dquot_cachep;
134
135 int register_quota_format(struct quota_format_type *fmt)
136 {
137         spin_lock(&dq_list_lock);
138         fmt->qf_next = quota_formats;
139         quota_formats = fmt;
140         spin_unlock(&dq_list_lock);
141         return 0;
142 }
143
144 void unregister_quota_format(struct quota_format_type *fmt)
145 {
146         struct quota_format_type **actqf;
147
148         spin_lock(&dq_list_lock);
149         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
150         if (*actqf)
151                 *actqf = (*actqf)->qf_next;
152         spin_unlock(&dq_list_lock);
153 }
154
155 static struct quota_format_type *find_quota_format(int id)
156 {
157         struct quota_format_type *actqf;
158
159         spin_lock(&dq_list_lock);
160         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
161         if (!actqf || !try_module_get(actqf->qf_owner)) {
162                 int qm;
163
164                 spin_unlock(&dq_list_lock);
165                 
166                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
167                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
168                         return NULL;
169
170                 spin_lock(&dq_list_lock);
171                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
172                 if (actqf && !try_module_get(actqf->qf_owner))
173                         actqf = NULL;
174         }
175         spin_unlock(&dq_list_lock);
176         return actqf;
177 }
178
179 static void put_quota_format(struct quota_format_type *fmt)
180 {
181         module_put(fmt->qf_owner);
182 }
183
184 /*
185  * Dquot List Management:
186  * The quota code uses three lists for dquot management: the inuse_list,
187  * free_dquots, and dquot_hash[] array. A single dquot structure may be
188  * on all three lists, depending on its current state.
189  *
190  * All dquots are placed to the end of inuse_list when first created, and this
191  * list is used for invalidate operation, which must look at every dquot.
192  *
193  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
194  * and this list is searched whenever we need an available dquot.  Dquots are
195  * removed from the list as soon as they are used again, and
196  * dqstats.free_dquots gives the number of dquots on the list. When
197  * dquot is invalidated it's completely released from memory.
198  *
199  * Dquots with a specific identity (device, type and id) are placed on
200  * one of the dquot_hash[] hash chains. The provides an efficient search
201  * mechanism to locate a specific dquot.
202  */
203
204 static LIST_HEAD(inuse_list);
205 static LIST_HEAD(free_dquots);
206 static unsigned int dq_hash_bits, dq_hash_mask;
207 static struct hlist_head *dquot_hash;
208
209 struct dqstats dqstats;
210
211 static void dqput(struct dquot *dquot);
212
213 static inline unsigned int
214 hashfn(const struct super_block *sb, unsigned int id, int type)
215 {
216         unsigned long tmp;
217
218         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
219         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
220 }
221
222 /*
223  * Following list functions expect dq_list_lock to be held
224  */
225 static inline void insert_dquot_hash(struct dquot *dquot)
226 {
227         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
228         hlist_add_head(&dquot->dq_hash, head);
229 }
230
231 static inline void remove_dquot_hash(struct dquot *dquot)
232 {
233         hlist_del_init(&dquot->dq_hash);
234 }
235
236 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
237 {
238         struct hlist_node *node;
239         struct dquot *dquot;
240
241         hlist_for_each (node, dquot_hash+hashent) {
242                 dquot = hlist_entry(node, struct dquot, dq_hash);
243                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
244                         return dquot;
245         }
246         return NODQUOT;
247 }
248
249 /* Add a dquot to the tail of the free list */
250 static inline void put_dquot_last(struct dquot *dquot)
251 {
252         list_add(&dquot->dq_free, free_dquots.prev);
253         dqstats.free_dquots++;
254 }
255
256 static inline void remove_free_dquot(struct dquot *dquot)
257 {
258         if (list_empty(&dquot->dq_free))
259                 return;
260         list_del_init(&dquot->dq_free);
261         dqstats.free_dquots--;
262 }
263
264 static inline void put_inuse(struct dquot *dquot)
265 {
266         /* We add to the back of inuse list so we don't have to restart
267          * when traversing this list and we block */
268         list_add(&dquot->dq_inuse, inuse_list.prev);
269         dqstats.allocated_dquots++;
270 }
271
272 static inline void remove_inuse(struct dquot *dquot)
273 {
274         dqstats.allocated_dquots--;
275         list_del(&dquot->dq_inuse);
276 }
277 /*
278  * End of list functions needing dq_list_lock
279  */
280
281 static void wait_on_dquot(struct dquot *dquot)
282 {
283         down(&dquot->dq_lock);
284         up(&dquot->dq_lock);
285 }
286
287 #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
288
289 int dquot_mark_dquot_dirty(struct dquot *dquot)
290 {
291         spin_lock(&dq_list_lock);
292         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
293                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
294                                 info[dquot->dq_type].dqi_dirty_list);
295         spin_unlock(&dq_list_lock);
296         return 0;
297 }
298
299 /* This function needs dq_list_lock */
300 static inline int clear_dquot_dirty(struct dquot *dquot)
301 {
302         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
303                 return 0;
304         list_del_init(&dquot->dq_dirty);
305         return 1;
306 }
307
308 void mark_info_dirty(struct super_block *sb, int type)
309 {
310         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
311 }
312 EXPORT_SYMBOL(mark_info_dirty);
313
314 /*
315  *      Read dquot from disk and alloc space for it
316  */
317
318 int dquot_acquire(struct dquot *dquot)
319 {
320         int ret = 0, ret2 = 0;
321         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
322
323         down(&dquot->dq_lock);
324         down(&dqopt->dqio_sem);
325         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
326                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
327         if (ret < 0)
328                 goto out_iolock;
329         set_bit(DQ_READ_B, &dquot->dq_flags);
330         /* Instantiate dquot if needed */
331         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
332                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
333                 /* Write the info if needed */
334                 if (info_dirty(&dqopt->info[dquot->dq_type]))
335                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
336                 if (ret < 0)
337                         goto out_iolock;
338                 if (ret2 < 0) {
339                         ret = ret2;
340                         goto out_iolock;
341                 }
342         }
343         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
344 out_iolock:
345         up(&dqopt->dqio_sem);
346         up(&dquot->dq_lock);
347         return ret;
348 }
349
350 /*
351  *      Write dquot to disk
352  */
353 int dquot_commit(struct dquot *dquot)
354 {
355         int ret = 0, ret2 = 0;
356         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
357
358         down(&dqopt->dqio_sem);
359         spin_lock(&dq_list_lock);
360         if (!clear_dquot_dirty(dquot)) {
361                 spin_unlock(&dq_list_lock);
362                 goto out_sem;
363         }
364         spin_unlock(&dq_list_lock);
365         /* Inactive dquot can be only if there was error during read/init
366          * => we have better not writing it */
367         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
368                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
369                 if (info_dirty(&dqopt->info[dquot->dq_type]))
370                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
371                 if (ret >= 0)
372                         ret = ret2;
373         }
374 out_sem:
375         up(&dqopt->dqio_sem);
376         return ret;
377 }
378
379 /*
380  *      Release dquot
381  */
382 int dquot_release(struct dquot *dquot)
383 {
384         int ret = 0, ret2 = 0;
385         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
386
387         down(&dquot->dq_lock);
388         /* Check whether we are not racing with some other dqget() */
389         if (atomic_read(&dquot->dq_count) > 1)
390                 goto out_dqlock;
391         down(&dqopt->dqio_sem);
392         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
393                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
394                 /* Write the info */
395                 if (info_dirty(&dqopt->info[dquot->dq_type]))
396                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
397                 if (ret >= 0)
398                         ret = ret2;
399         }
400         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
401         up(&dqopt->dqio_sem);
402 out_dqlock:
403         up(&dquot->dq_lock);
404         return ret;
405 }
406
407 /* Invalidate all dquots on the list. Note that this function is called after
408  * quota is disabled and pointers from inodes removed so there cannot be new
409  * quota users. Also because we hold dqonoff_sem there can be no quota users
410  * for this sb+type at all. */
411 static void invalidate_dquots(struct super_block *sb, int type)
412 {
413         struct dquot *dquot, *tmp;
414
415         spin_lock(&dq_list_lock);
416         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
417                 if (dquot->dq_sb != sb)
418                         continue;
419                 if (dquot->dq_type != type)
420                         continue;
421 #ifdef __DQUOT_PARANOIA
422                 if (atomic_read(&dquot->dq_count))
423                         BUG();
424 #endif
425                 /* Quota now has no users and it has been written on last dqput() */
426                 remove_dquot_hash(dquot);
427                 remove_free_dquot(dquot);
428                 remove_inuse(dquot);
429                 kmem_cache_free(dquot_cachep, dquot);
430         }
431         spin_unlock(&dq_list_lock);
432 }
433
434 int vfs_quota_sync(struct super_block *sb, int type)
435 {
436         struct list_head *dirty;
437         struct dquot *dquot;
438         struct quota_info *dqopt = sb_dqopt(sb);
439         int cnt;
440
441         down(&dqopt->dqonoff_sem);
442         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
443                 if (type != -1 && cnt != type)
444                         continue;
445                 if (!sb_has_quota_enabled(sb, cnt))
446                         continue;
447                 spin_lock(&dq_list_lock);
448                 dirty = &dqopt->info[cnt].dqi_dirty_list;
449                 while (!list_empty(dirty)) {
450                         dquot = list_entry(dirty->next, struct dquot, dq_dirty);
451                         /* Dirty and inactive can be only bad dquot... */
452                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
453                                 clear_dquot_dirty(dquot);
454                                 continue;
455                         }
456                         /* Now we have active dquot from which someone is
457                          * holding reference so we can safely just increase
458                          * use count */
459                         atomic_inc(&dquot->dq_count);
460                         dqstats.lookups++;
461                         spin_unlock(&dq_list_lock);
462                         sb->dq_op->write_dquot(dquot);
463                         dqput(dquot);
464                         spin_lock(&dq_list_lock);
465                 }
466                 spin_unlock(&dq_list_lock);
467         }
468
469         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
470                 if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
471                         && info_dirty(&dqopt->info[cnt]))
472                         sb->dq_op->write_info(sb, cnt);
473         spin_lock(&dq_list_lock);
474         dqstats.syncs++;
475         spin_unlock(&dq_list_lock);
476         up(&dqopt->dqonoff_sem);
477
478         return 0;
479 }
480
481 /* Free unused dquots from cache */
482 static void prune_dqcache(int count)
483 {
484         struct list_head *head;
485         struct dquot *dquot;
486
487         head = free_dquots.prev;
488         while (head != &free_dquots && count) {
489                 dquot = list_entry(head, struct dquot, dq_free);
490                 remove_dquot_hash(dquot);
491                 remove_free_dquot(dquot);
492                 remove_inuse(dquot);
493                 kmem_cache_free(dquot_cachep, dquot);
494                 count--;
495                 head = free_dquots.prev;
496         }
497 }
498
499 /*
500  * This is called from kswapd when we think we need some
501  * more memory
502  */
503
504 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
505 {
506         if (nr) {
507                 spin_lock(&dq_list_lock);
508                 prune_dqcache(nr);
509                 spin_unlock(&dq_list_lock);
510         }
511         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
512 }
513
514 /*
515  * Put reference to dquot
516  * NOTE: If you change this function please check whether dqput_blocks() works right...
517  * MUST be called with either dqptr_sem or dqonoff_sem held
518  */
519 static void dqput(struct dquot *dquot)
520 {
521         if (!dquot)
522                 return;
523 #ifdef __DQUOT_PARANOIA
524         if (!atomic_read(&dquot->dq_count)) {
525                 printk("VFS: dqput: trying to free free dquot\n");
526                 printk("VFS: device %s, dquot of %s %d\n",
527                         dquot->dq_sb->s_id,
528                         quotatypes[dquot->dq_type],
529                         dquot->dq_id);
530                 BUG();
531         }
532 #endif
533         
534         spin_lock(&dq_list_lock);
535         dqstats.drops++;
536         spin_unlock(&dq_list_lock);
537 we_slept:
538         spin_lock(&dq_list_lock);
539         if (atomic_read(&dquot->dq_count) > 1) {
540                 /* We have more than one user... nothing to do */
541                 atomic_dec(&dquot->dq_count);
542                 spin_unlock(&dq_list_lock);
543                 return;
544         }
545         /* Need to release dquot? */
546         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
547                 spin_unlock(&dq_list_lock);
548                 /* Commit dquot before releasing */
549                 dquot->dq_sb->dq_op->write_dquot(dquot);
550                 goto we_slept;
551         }
552         /* Clear flag in case dquot was inactive (something bad happened) */
553         clear_dquot_dirty(dquot);
554         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
555                 spin_unlock(&dq_list_lock);
556                 dquot->dq_sb->dq_op->release_dquot(dquot);
557                 goto we_slept;
558         }
559         atomic_dec(&dquot->dq_count);
560 #ifdef __DQUOT_PARANOIA
561         /* sanity check */
562         if (!list_empty(&dquot->dq_free))
563                 BUG();
564 #endif
565         put_dquot_last(dquot);
566         spin_unlock(&dq_list_lock);
567 }
568
569 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
570 {
571         struct dquot *dquot;
572
573         dquot = kmem_cache_alloc(dquot_cachep, SLAB_NOFS);
574         if(!dquot)
575                 return NODQUOT;
576
577         memset((caddr_t)dquot, 0, sizeof(struct dquot));
578         sema_init(&dquot->dq_lock, 1);
579         INIT_LIST_HEAD(&dquot->dq_free);
580         INIT_LIST_HEAD(&dquot->dq_inuse);
581         INIT_HLIST_NODE(&dquot->dq_hash);
582         INIT_LIST_HEAD(&dquot->dq_dirty);
583         dquot->dq_sb = sb;
584         dquot->dq_type = type;
585         atomic_set(&dquot->dq_count, 1);
586
587         return dquot;
588 }
589
590 /*
591  * Get reference to dquot
592  * MUST be called with either dqptr_sem or dqonoff_sem held
593  */
594 static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
595 {
596         unsigned int hashent = hashfn(sb, id, type);
597         struct dquot *dquot, *empty = NODQUOT;
598
599         if (!sb_has_quota_enabled(sb, type))
600                 return NODQUOT;
601 we_slept:
602         spin_lock(&dq_list_lock);
603         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
604                 if (empty == NODQUOT) {
605                         spin_unlock(&dq_list_lock);
606                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
607                                 schedule();     /* Try to wait for a moment... */
608                         goto we_slept;
609                 }
610                 dquot = empty;
611                 dquot->dq_id = id;
612                 /* all dquots go on the inuse_list */
613                 put_inuse(dquot);
614                 /* hash it first so it can be found */
615                 insert_dquot_hash(dquot);
616                 dqstats.lookups++;
617                 spin_unlock(&dq_list_lock);
618         } else {
619                 if (!atomic_read(&dquot->dq_count))
620                         remove_free_dquot(dquot);
621                 atomic_inc(&dquot->dq_count);
622                 dqstats.cache_hits++;
623                 dqstats.lookups++;
624                 spin_unlock(&dq_list_lock);
625                 if (empty)
626                         kmem_cache_free(dquot_cachep, empty);
627         }
628         /* Wait for dq_lock - after this we know that either dquot_release() is already
629          * finished or it will be canceled due to dq_count > 1 test */
630         wait_on_dquot(dquot);
631         /* Read the dquot and instantiate it (everything done only if needed) */
632         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
633                 dqput(dquot);
634                 return NODQUOT;
635         }
636 #ifdef __DQUOT_PARANOIA
637         if (!dquot->dq_sb)      /* Has somebody invalidated entry under us? */
638                 BUG();
639 #endif
640
641         return dquot;
642 }
643
644 static int dqinit_needed(struct inode *inode, int type)
645 {
646         int cnt;
647
648         if (IS_NOQUOTA(inode))
649                 return 0;
650         if (type != -1)
651                 return inode->i_dquot[type] == NODQUOT;
652         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
653                 if (inode->i_dquot[cnt] == NODQUOT)
654                         return 1;
655         return 0;
656 }
657
658 /* This routine is guarded by dqonoff_sem semaphore */
659 static void add_dquot_ref(struct super_block *sb, int type)
660 {
661         struct list_head *p;
662
663 restart:
664         file_list_lock();
665         list_for_each(p, &sb->s_files) {
666                 struct file *filp = list_entry(p, struct file, f_u.fu_list);
667                 struct inode *inode = filp->f_dentry->d_inode;
668                 if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
669                         struct dentry *dentry = dget(filp->f_dentry);
670                         file_list_unlock();
671                         sb->dq_op->initialize(inode, type);
672                         dput(dentry);
673                         /* As we may have blocked we had better restart... */
674                         goto restart;
675                 }
676         }
677         file_list_unlock();
678 }
679
680 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
681 static inline int dqput_blocks(struct dquot *dquot)
682 {
683         if (atomic_read(&dquot->dq_count) <= 1)
684                 return 1;
685         return 0;
686 }
687
688 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
689 /* We can't race with anybody because we hold dqptr_sem for writing... */
690 int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
691 {
692         struct dquot *dquot = inode->i_dquot[type];
693
694         inode->i_dquot[type] = NODQUOT;
695         if (dquot != NODQUOT) {
696                 if (dqput_blocks(dquot)) {
697 #ifdef __DQUOT_PARANOIA
698                         if (atomic_read(&dquot->dq_count) != 1)
699                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
700 #endif
701                         spin_lock(&dq_list_lock);
702                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
703                         spin_unlock(&dq_list_lock);
704                         return 1;
705                 }
706                 else
707                         dqput(dquot);   /* We have guaranteed we won't block */
708         }
709         return 0;
710 }
711
712 /* Free list of dquots - called from inode.c */
713 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
714 static void put_dquot_list(struct list_head *tofree_head)
715 {
716         struct list_head *act_head;
717         struct dquot *dquot;
718
719         act_head = tofree_head->next;
720         /* So now we have dquots on the list... Just free them */
721         while (act_head != tofree_head) {
722                 dquot = list_entry(act_head, struct dquot, dq_free);
723                 act_head = act_head->next;
724                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
725                 dqput(dquot);
726         }
727 }
728
729 /* Gather all references from inodes and drop them */
730 static void drop_dquot_ref(struct super_block *sb, int type)
731 {
732         LIST_HEAD(tofree_head);
733
734         /* We need to be guarded against prune_icache to reach all the
735          * inodes - otherwise some can be on the local list of prune_icache */
736         down(&iprune_sem);
737         down_write(&sb_dqopt(sb)->dqptr_sem);
738         remove_dquot_ref(sb, type, &tofree_head);
739         up_write(&sb_dqopt(sb)->dqptr_sem);
740         up(&iprune_sem);
741         put_dquot_list(&tofree_head);
742 }
743
744 static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
745 {
746         dquot->dq_dqb.dqb_curinodes += number;
747 }
748
749 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
750 {
751         dquot->dq_dqb.dqb_curspace += number;
752 }
753
754 static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
755 {
756         if (dquot->dq_dqb.dqb_curinodes > number)
757                 dquot->dq_dqb.dqb_curinodes -= number;
758         else
759                 dquot->dq_dqb.dqb_curinodes = 0;
760         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
761                 dquot->dq_dqb.dqb_itime = (time_t) 0;
762         clear_bit(DQ_INODES_B, &dquot->dq_flags);
763 }
764
765 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
766 {
767         if (dquot->dq_dqb.dqb_curspace > number)
768                 dquot->dq_dqb.dqb_curspace -= number;
769         else
770                 dquot->dq_dqb.dqb_curspace = 0;
771         if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
772                 dquot->dq_dqb.dqb_btime = (time_t) 0;
773         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
774 }
775
776 static int flag_print_warnings = 1;
777
778 static inline int need_print_warning(struct dquot *dquot)
779 {
780         if (!flag_print_warnings)
781                 return 0;
782
783         switch (dquot->dq_type) {
784                 case USRQUOTA:
785                         return current->fsuid == dquot->dq_id;
786                 case GRPQUOTA:
787                         return in_group_p(dquot->dq_id);
788         }
789         return 0;
790 }
791
792 /* Values of warnings */
793 #define NOWARN 0
794 #define IHARDWARN 1
795 #define ISOFTLONGWARN 2
796 #define ISOFTWARN 3
797 #define BHARDWARN 4
798 #define BSOFTLONGWARN 5
799 #define BSOFTWARN 6
800
801 /* Print warning to user which exceeded quota */
802 static void print_warning(struct dquot *dquot, const char warntype)
803 {
804         char *msg = NULL;
805         int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
806           ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
807
808         if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
809                 return;
810
811         tty_write_message(current->signal->tty, dquot->dq_sb->s_id);
812         if (warntype == ISOFTWARN || warntype == BSOFTWARN)
813                 tty_write_message(current->signal->tty, ": warning, ");
814         else
815                 tty_write_message(current->signal->tty, ": write failed, ");
816         tty_write_message(current->signal->tty, quotatypes[dquot->dq_type]);
817         switch (warntype) {
818                 case IHARDWARN:
819                         msg = " file limit reached.\r\n";
820                         break;
821                 case ISOFTLONGWARN:
822                         msg = " file quota exceeded too long.\r\n";
823                         break;
824                 case ISOFTWARN:
825                         msg = " file quota exceeded.\r\n";
826                         break;
827                 case BHARDWARN:
828                         msg = " block limit reached.\r\n";
829                         break;
830                 case BSOFTLONGWARN:
831                         msg = " block quota exceeded too long.\r\n";
832                         break;
833                 case BSOFTWARN:
834                         msg = " block quota exceeded.\r\n";
835                         break;
836         }
837         tty_write_message(current->signal->tty, msg);
838 }
839
840 static inline void flush_warnings(struct dquot **dquots, char *warntype)
841 {
842         int i;
843
844         for (i = 0; i < MAXQUOTAS; i++)
845                 if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
846                         print_warning(dquots[i], warntype[i]);
847 }
848
849 static inline char ignore_hardlimit(struct dquot *dquot)
850 {
851         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
852
853         return capable(CAP_SYS_RESOURCE) &&
854             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
855 }
856
857 /* needs dq_data_lock */
858 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
859 {
860         *warntype = NOWARN;
861         if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
862                 return QUOTA_OK;
863
864         if (dquot->dq_dqb.dqb_ihardlimit &&
865            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
866             !ignore_hardlimit(dquot)) {
867                 *warntype = IHARDWARN;
868                 return NO_QUOTA;
869         }
870
871         if (dquot->dq_dqb.dqb_isoftlimit &&
872            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
873             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
874             !ignore_hardlimit(dquot)) {
875                 *warntype = ISOFTLONGWARN;
876                 return NO_QUOTA;
877         }
878
879         if (dquot->dq_dqb.dqb_isoftlimit &&
880            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
881             dquot->dq_dqb.dqb_itime == 0) {
882                 *warntype = ISOFTWARN;
883                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
884         }
885
886         return QUOTA_OK;
887 }
888
889 /* needs dq_data_lock */
890 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
891 {
892         *warntype = 0;
893         if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
894                 return QUOTA_OK;
895
896         if (dquot->dq_dqb.dqb_bhardlimit &&
897            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
898             !ignore_hardlimit(dquot)) {
899                 if (!prealloc)
900                         *warntype = BHARDWARN;
901                 return NO_QUOTA;
902         }
903
904         if (dquot->dq_dqb.dqb_bsoftlimit &&
905            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
906             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
907             !ignore_hardlimit(dquot)) {
908                 if (!prealloc)
909                         *warntype = BSOFTLONGWARN;
910                 return NO_QUOTA;
911         }
912
913         if (dquot->dq_dqb.dqb_bsoftlimit &&
914            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
915             dquot->dq_dqb.dqb_btime == 0) {
916                 if (!prealloc) {
917                         *warntype = BSOFTWARN;
918                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
919                 }
920                 else
921                         /*
922                          * We don't allow preallocation to exceed softlimit so exceeding will
923                          * be always printed
924                          */
925                         return NO_QUOTA;
926         }
927
928         return QUOTA_OK;
929 }
930
931 /*
932  *      Initialize quota pointers in inode
933  *      Transaction must be started at entry
934  */
935 int dquot_initialize(struct inode *inode, int type)
936 {
937         unsigned int id = 0;
938         int cnt, ret = 0;
939
940         /* First test before acquiring semaphore - solves deadlocks when we
941          * re-enter the quota code and are already holding the semaphore */
942         if (IS_NOQUOTA(inode))
943                 return 0;
944         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
945         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
946         if (IS_NOQUOTA(inode))
947                 goto out_err;
948         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
949                 if (type != -1 && cnt != type)
950                         continue;
951                 if (inode->i_dquot[cnt] == NODQUOT) {
952                         switch (cnt) {
953                                 case USRQUOTA:
954                                         id = inode->i_uid;
955                                         break;
956                                 case GRPQUOTA:
957                                         id = inode->i_gid;
958                                         break;
959                         }
960                         inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
961                 }
962         }
963 out_err:
964         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
965         return ret;
966 }
967
968 /*
969  *      Release all quotas referenced by inode
970  *      Transaction must be started at an entry
971  */
972 int dquot_drop(struct inode *inode)
973 {
974         int cnt;
975
976         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
977         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
978                 if (inode->i_dquot[cnt] != NODQUOT) {
979                         dqput(inode->i_dquot[cnt]);
980                         inode->i_dquot[cnt] = NODQUOT;
981                 }
982         }
983         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
984         return 0;
985 }
986
987 /*
988  * Following four functions update i_blocks+i_bytes fields and
989  * quota information (together with appropriate checks)
990  * NOTE: We absolutely rely on the fact that caller dirties
991  * the inode (usually macros in quotaops.h care about this) and
992  * holds a handle for the current transaction so that dquot write and
993  * inode write go into the same transaction.
994  */
995
996 /*
997  * This operation can block, but only after everything is updated
998  */
999 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1000 {
1001         int cnt, ret = NO_QUOTA;
1002         char warntype[MAXQUOTAS];
1003
1004         /* First test before acquiring semaphore - solves deadlocks when we
1005          * re-enter the quota code and are already holding the semaphore */
1006         if (IS_NOQUOTA(inode)) {
1007 out_add:
1008                 inode_add_bytes(inode, number);
1009                 return QUOTA_OK;
1010         }
1011         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1012                 warntype[cnt] = NOWARN;
1013
1014         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1015         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1016                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1017                 goto out_add;
1018         }
1019         spin_lock(&dq_data_lock);
1020         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1021                 if (inode->i_dquot[cnt] == NODQUOT)
1022                         continue;
1023                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1024                         goto warn_put_all;
1025         }
1026         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1027                 if (inode->i_dquot[cnt] == NODQUOT)
1028                         continue;
1029                 dquot_incr_space(inode->i_dquot[cnt], number);
1030         }
1031         inode_add_bytes(inode, number);
1032         ret = QUOTA_OK;
1033 warn_put_all:
1034         spin_unlock(&dq_data_lock);
1035         if (ret == QUOTA_OK)
1036                 /* Dirtify all the dquots - this can block when journalling */
1037                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1038                         if (inode->i_dquot[cnt])
1039                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1040         flush_warnings(inode->i_dquot, warntype);
1041         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1042         return ret;
1043 }
1044
1045 /*
1046  * This operation can block, but only after everything is updated
1047  */
1048 int dquot_alloc_inode(const struct inode *inode, unsigned long number)
1049 {
1050         int cnt, ret = NO_QUOTA;
1051         char warntype[MAXQUOTAS];
1052
1053         /* First test before acquiring semaphore - solves deadlocks when we
1054          * re-enter the quota code and are already holding the semaphore */
1055         if (IS_NOQUOTA(inode))
1056                 return QUOTA_OK;
1057         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1058                 warntype[cnt] = NOWARN;
1059         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1060         if (IS_NOQUOTA(inode)) {
1061                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1062                 return QUOTA_OK;
1063         }
1064         spin_lock(&dq_data_lock);
1065         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1066                 if (inode->i_dquot[cnt] == NODQUOT)
1067                         continue;
1068                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1069                         goto warn_put_all;
1070         }
1071
1072         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1073                 if (inode->i_dquot[cnt] == NODQUOT)
1074                         continue;
1075                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1076         }
1077         ret = QUOTA_OK;
1078 warn_put_all:
1079         spin_unlock(&dq_data_lock);
1080         if (ret == QUOTA_OK)
1081                 /* Dirtify all the dquots - this can block when journalling */
1082                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1083                         if (inode->i_dquot[cnt])
1084                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1085         flush_warnings((struct dquot **)inode->i_dquot, warntype);
1086         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1087         return ret;
1088 }
1089
1090 /*
1091  * This operation can block, but only after everything is updated
1092  */
1093 int dquot_free_space(struct inode *inode, qsize_t number)
1094 {
1095         unsigned int cnt;
1096
1097         /* First test before acquiring semaphore - solves deadlocks when we
1098          * re-enter the quota code and are already holding the semaphore */
1099         if (IS_NOQUOTA(inode)) {
1100 out_sub:
1101                 inode_sub_bytes(inode, number);
1102                 return QUOTA_OK;
1103         }
1104         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1105         /* Now recheck reliably when holding dqptr_sem */
1106         if (IS_NOQUOTA(inode)) {
1107                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1108                 goto out_sub;
1109         }
1110         spin_lock(&dq_data_lock);
1111         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1112                 if (inode->i_dquot[cnt] == NODQUOT)
1113                         continue;
1114                 dquot_decr_space(inode->i_dquot[cnt], number);
1115         }
1116         inode_sub_bytes(inode, number);
1117         spin_unlock(&dq_data_lock);
1118         /* Dirtify all the dquots - this can block when journalling */
1119         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1120                 if (inode->i_dquot[cnt])
1121                         mark_dquot_dirty(inode->i_dquot[cnt]);
1122         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1123         return QUOTA_OK;
1124 }
1125
1126 /*
1127  * This operation can block, but only after everything is updated
1128  */
1129 int dquot_free_inode(const struct inode *inode, unsigned long number)
1130 {
1131         unsigned int cnt;
1132
1133         /* First test before acquiring semaphore - solves deadlocks when we
1134          * re-enter the quota code and are already holding the semaphore */
1135         if (IS_NOQUOTA(inode))
1136                 return QUOTA_OK;
1137         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1138         /* Now recheck reliably when holding dqptr_sem */
1139         if (IS_NOQUOTA(inode)) {
1140                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1141                 return QUOTA_OK;
1142         }
1143         spin_lock(&dq_data_lock);
1144         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1145                 if (inode->i_dquot[cnt] == NODQUOT)
1146                         continue;
1147                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1148         }
1149         spin_unlock(&dq_data_lock);
1150         /* Dirtify all the dquots - this can block when journalling */
1151         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1152                 if (inode->i_dquot[cnt])
1153                         mark_dquot_dirty(inode->i_dquot[cnt]);
1154         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1155         return QUOTA_OK;
1156 }
1157
1158 /*
1159  * Transfer the number of inode and blocks from one diskquota to an other.
1160  *
1161  * This operation can block, but only after everything is updated
1162  * A transaction must be started when entering this function.
1163  */
1164 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1165 {
1166         qsize_t space;
1167         struct dquot *transfer_from[MAXQUOTAS];
1168         struct dquot *transfer_to[MAXQUOTAS];
1169         int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
1170             chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
1171         char warntype[MAXQUOTAS];
1172
1173         /* First test before acquiring semaphore - solves deadlocks when we
1174          * re-enter the quota code and are already holding the semaphore */
1175         if (IS_NOQUOTA(inode))
1176                 return QUOTA_OK;
1177         /* Clear the arrays */
1178         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1179                 transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
1180                 warntype[cnt] = NOWARN;
1181         }
1182         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1183         /* Now recheck reliably when holding dqptr_sem */
1184         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1185                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1186                 return QUOTA_OK;
1187         }
1188         /* First build the transfer_to list - here we can block on
1189          * reading/instantiating of dquots.  We know that the transaction for
1190          * us was already started so we don't violate lock ranking here */
1191         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1192                 switch (cnt) {
1193                         case USRQUOTA:
1194                                 if (!chuid)
1195                                         continue;
1196                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1197                                 break;
1198                         case GRPQUOTA:
1199                                 if (!chgid)
1200                                         continue;
1201                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1202                                 break;
1203                 }
1204         }
1205         spin_lock(&dq_data_lock);
1206         space = inode_get_bytes(inode);
1207         /* Build the transfer_from list and check the limits */
1208         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1209                 if (transfer_to[cnt] == NODQUOT)
1210                         continue;
1211                 transfer_from[cnt] = inode->i_dquot[cnt];
1212                 if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
1213                     check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
1214                         goto warn_put_all;
1215         }
1216
1217         /*
1218          * Finally perform the needed transfer from transfer_from to transfer_to
1219          */
1220         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1221                 /*
1222                  * Skip changes for same uid or gid or for turned off quota-type.
1223                  */
1224                 if (transfer_to[cnt] == NODQUOT)
1225                         continue;
1226
1227                 /* Due to IO error we might not have transfer_from[] structure */
1228                 if (transfer_from[cnt]) {
1229                         dquot_decr_inodes(transfer_from[cnt], 1);
1230                         dquot_decr_space(transfer_from[cnt], space);
1231                 }
1232
1233                 dquot_incr_inodes(transfer_to[cnt], 1);
1234                 dquot_incr_space(transfer_to[cnt], space);
1235
1236                 inode->i_dquot[cnt] = transfer_to[cnt];
1237         }
1238         ret = QUOTA_OK;
1239 warn_put_all:
1240         spin_unlock(&dq_data_lock);
1241         /* Dirtify all the dquots - this can block when journalling */
1242         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1243                 if (transfer_from[cnt])
1244                         mark_dquot_dirty(transfer_from[cnt]);
1245                 if (transfer_to[cnt])
1246                         mark_dquot_dirty(transfer_to[cnt]);
1247         }
1248         flush_warnings(transfer_to, warntype);
1249         
1250         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1251                 if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
1252                         dqput(transfer_from[cnt]);
1253                 if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
1254                         dqput(transfer_to[cnt]);
1255         }
1256         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1257         return ret;
1258 }
1259
1260 /*
1261  * Write info of quota file to disk
1262  */
1263 int dquot_commit_info(struct super_block *sb, int type)
1264 {
1265         int ret;
1266         struct quota_info *dqopt = sb_dqopt(sb);
1267
1268         down(&dqopt->dqio_sem);
1269         ret = dqopt->ops[type]->write_file_info(sb, type);
1270         up(&dqopt->dqio_sem);
1271         return ret;
1272 }
1273
1274 /*
1275  * Definitions of diskquota operations.
1276  */
1277 struct dquot_operations dquot_operations = {
1278         .initialize     = dquot_initialize,
1279         .drop           = dquot_drop,
1280         .alloc_space    = dquot_alloc_space,
1281         .alloc_inode    = dquot_alloc_inode,
1282         .free_space     = dquot_free_space,
1283         .free_inode     = dquot_free_inode,
1284         .transfer       = dquot_transfer,
1285         .write_dquot    = dquot_commit,
1286         .acquire_dquot  = dquot_acquire,
1287         .release_dquot  = dquot_release,
1288         .mark_dirty     = dquot_mark_dquot_dirty,
1289         .write_info     = dquot_commit_info
1290 };
1291
1292 static inline void set_enable_flags(struct quota_info *dqopt, int type)
1293 {
1294         switch (type) {
1295                 case USRQUOTA:
1296                         dqopt->flags |= DQUOT_USR_ENABLED;
1297                         break;
1298                 case GRPQUOTA:
1299                         dqopt->flags |= DQUOT_GRP_ENABLED;
1300                         break;
1301         }
1302 }
1303
1304 static inline void reset_enable_flags(struct quota_info *dqopt, int type)
1305 {
1306         switch (type) {
1307                 case USRQUOTA:
1308                         dqopt->flags &= ~DQUOT_USR_ENABLED;
1309                         break;
1310                 case GRPQUOTA:
1311                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
1312                         break;
1313         }
1314 }
1315
1316 /*
1317  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1318  */
1319 int vfs_quota_off(struct super_block *sb, int type)
1320 {
1321         int cnt;
1322         struct quota_info *dqopt = sb_dqopt(sb);
1323         struct inode *toputinode[MAXQUOTAS];
1324         struct vfsmount *toputmnt[MAXQUOTAS];
1325
1326         /* We need to serialize quota_off() for device */
1327         down(&dqopt->dqonoff_sem);
1328         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1329                 toputinode[cnt] = NULL;
1330                 toputmnt[cnt] = NULL;
1331                 if (type != -1 && cnt != type)
1332                         continue;
1333                 if (!sb_has_quota_enabled(sb, cnt))
1334                         continue;
1335                 reset_enable_flags(dqopt, cnt);
1336
1337                 /* Note: these are blocking operations */
1338                 drop_dquot_ref(sb, cnt);
1339                 invalidate_dquots(sb, cnt);
1340                 /*
1341                  * Now all dquots should be invalidated, all writes done so we should be only
1342                  * users of the info. No locks needed.
1343                  */
1344                 if (info_dirty(&dqopt->info[cnt]))
1345                         sb->dq_op->write_info(sb, cnt);
1346                 if (dqopt->ops[cnt]->free_file_info)
1347                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1348                 put_quota_format(dqopt->info[cnt].dqi_format);
1349
1350                 toputinode[cnt] = dqopt->files[cnt];
1351                 toputmnt[cnt] = dqopt->mnt[cnt];
1352                 dqopt->files[cnt] = NULL;
1353                 dqopt->mnt[cnt] = NULL;
1354                 dqopt->info[cnt].dqi_flags = 0;
1355                 dqopt->info[cnt].dqi_igrace = 0;
1356                 dqopt->info[cnt].dqi_bgrace = 0;
1357                 dqopt->ops[cnt] = NULL;
1358         }
1359         up(&dqopt->dqonoff_sem);
1360         /* Sync the superblock so that buffers with quota data are written to
1361          * disk (and so userspace sees correct data afterwards).
1362          * The reference to vfsmnt we are still holding protects us from
1363          * umount (we don't have it only when quotas are turned on/off for
1364          * journal replay but in that case we are guarded by the fs anyway). */
1365         if (sb->s_op->sync_fs)
1366                 sb->s_op->sync_fs(sb, 1);
1367         sync_blockdev(sb->s_bdev);
1368         /* Now the quota files are just ordinary files and we can set the
1369          * inode flags back. Moreover we discard the pagecache so that
1370          * userspace sees the writes we did bypassing the pagecache. We
1371          * must also discard the blockdev buffers so that we see the
1372          * changes done by userspace on the next quotaon() */
1373         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1374                 if (toputinode[cnt]) {
1375                         down(&dqopt->dqonoff_sem);
1376                         /* If quota was reenabled in the meantime, we have
1377                          * nothing to do */
1378                         if (!sb_has_quota_enabled(sb, cnt)) {
1379                                 down(&toputinode[cnt]->i_sem);
1380                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1381                                   S_NOATIME | S_NOQUOTA);
1382                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1383                                 up(&toputinode[cnt]->i_sem);
1384                                 mark_inode_dirty(toputinode[cnt]);
1385                                 iput(toputinode[cnt]);
1386                         }
1387                         up(&dqopt->dqonoff_sem);
1388                         /* We don't hold the reference when we turned on quotas
1389                          * just for the journal replay... */
1390                         if (toputmnt[cnt])
1391                                 mntput(toputmnt[cnt]);
1392                 }
1393         if (sb->s_bdev)
1394                 invalidate_bdev(sb->s_bdev, 0);
1395         return 0;
1396 }
1397
1398 /*
1399  *      Turn quotas on on a device
1400  */
1401
1402 /* Helper function when we already have the inode */
1403 static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
1404 {
1405         struct quota_format_type *fmt = find_quota_format(format_id);
1406         struct super_block *sb = inode->i_sb;
1407         struct quota_info *dqopt = sb_dqopt(sb);
1408         int error;
1409         int oldflags = -1;
1410
1411         if (!fmt)
1412                 return -ESRCH;
1413         if (!S_ISREG(inode->i_mode)) {
1414                 error = -EACCES;
1415                 goto out_fmt;
1416         }
1417         if (IS_RDONLY(inode)) {
1418                 error = -EROFS;
1419                 goto out_fmt;
1420         }
1421         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1422                 error = -EINVAL;
1423                 goto out_fmt;
1424         }
1425
1426         /* As we bypass the pagecache we must now flush the inode so that
1427          * we see all the changes from userspace... */
1428         write_inode_now(inode, 1);
1429         /* And now flush the block cache so that kernel sees the changes */
1430         invalidate_bdev(sb->s_bdev, 0);
1431         down(&inode->i_sem);
1432         down(&dqopt->dqonoff_sem);
1433         if (sb_has_quota_enabled(sb, type)) {
1434                 error = -EBUSY;
1435                 goto out_lock;
1436         }
1437         /* We don't want quota and atime on quota files (deadlocks possible)
1438          * Also nobody should write to the file - we use special IO operations
1439          * which ignore the immutable bit. */
1440         down_write(&dqopt->dqptr_sem);
1441         oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1442         inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1443         up_write(&dqopt->dqptr_sem);
1444         sb->dq_op->drop(inode);
1445
1446         error = -EIO;
1447         dqopt->files[type] = igrab(inode);
1448         if (!dqopt->files[type])
1449                 goto out_lock;
1450         error = -EINVAL;
1451         if (!fmt->qf_ops->check_quota_file(sb, type))
1452                 goto out_file_init;
1453
1454         dqopt->ops[type] = fmt->qf_ops;
1455         dqopt->info[type].dqi_format = fmt;
1456         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1457         down(&dqopt->dqio_sem);
1458         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1459                 up(&dqopt->dqio_sem);
1460                 goto out_file_init;
1461         }
1462         up(&dqopt->dqio_sem);
1463         up(&inode->i_sem);
1464         set_enable_flags(dqopt, type);
1465
1466         add_dquot_ref(sb, type);
1467         up(&dqopt->dqonoff_sem);
1468
1469         return 0;
1470
1471 out_file_init:
1472         dqopt->files[type] = NULL;
1473         iput(inode);
1474 out_lock:
1475         up(&dqopt->dqonoff_sem);
1476         if (oldflags != -1) {
1477                 down_write(&dqopt->dqptr_sem);
1478                 /* Set the flags back (in the case of accidental quotaon()
1479                  * on a wrong file we don't want to mess up the flags) */
1480                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1481                 inode->i_flags |= oldflags;
1482                 up_write(&dqopt->dqptr_sem);
1483         }
1484         up(&inode->i_sem);
1485 out_fmt:
1486         put_quota_format(fmt);
1487
1488         return error; 
1489 }
1490
1491 /* Actual function called from quotactl() */
1492 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
1493 {
1494         struct nameidata nd;
1495         int error;
1496
1497         error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1498         if (error < 0)
1499                 return error;
1500         error = security_quota_on(nd.dentry);
1501         if (error)
1502                 goto out_path;
1503         /* Quota file not on the same filesystem? */
1504         if (nd.mnt->mnt_sb != sb)
1505                 error = -EXDEV;
1506         else {
1507                 error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
1508                 if (!error)
1509                         sb_dqopt(sb)->mnt[type] = mntget(nd.mnt);
1510         }
1511 out_path:
1512         path_release(&nd);
1513         return error;
1514 }
1515
1516 /*
1517  * This function is used when filesystem needs to initialize quotas
1518  * during mount time.
1519  */
1520 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
1521                 int format_id, int type)
1522 {
1523         struct dentry *dentry;
1524         int error;
1525
1526         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
1527         if (IS_ERR(dentry))
1528                 return PTR_ERR(dentry);
1529
1530         error = security_quota_on(dentry);
1531         if (!error)
1532                 error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
1533
1534         dput(dentry);
1535         return error;
1536 }
1537
1538 /* Generic routine for getting common part of quota structure */
1539 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
1540 {
1541         struct mem_dqblk *dm = &dquot->dq_dqb;
1542
1543         spin_lock(&dq_data_lock);
1544         di->dqb_bhardlimit = dm->dqb_bhardlimit;
1545         di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
1546         di->dqb_curspace = dm->dqb_curspace;
1547         di->dqb_ihardlimit = dm->dqb_ihardlimit;
1548         di->dqb_isoftlimit = dm->dqb_isoftlimit;
1549         di->dqb_curinodes = dm->dqb_curinodes;
1550         di->dqb_btime = dm->dqb_btime;
1551         di->dqb_itime = dm->dqb_itime;
1552         di->dqb_valid = QIF_ALL;
1553         spin_unlock(&dq_data_lock);
1554 }
1555
1556 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1557 {
1558         struct dquot *dquot;
1559
1560         down(&sb_dqopt(sb)->dqonoff_sem);
1561         if (!(dquot = dqget(sb, id, type))) {
1562                 up(&sb_dqopt(sb)->dqonoff_sem);
1563                 return -ESRCH;
1564         }
1565         do_get_dqblk(dquot, di);
1566         dqput(dquot);
1567         up(&sb_dqopt(sb)->dqonoff_sem);
1568         return 0;
1569 }
1570
1571 /* Generic routine for setting common part of quota structure */
1572 static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
1573 {
1574         struct mem_dqblk *dm = &dquot->dq_dqb;
1575         int check_blim = 0, check_ilim = 0;
1576
1577         spin_lock(&dq_data_lock);
1578         if (di->dqb_valid & QIF_SPACE) {
1579                 dm->dqb_curspace = di->dqb_curspace;
1580                 check_blim = 1;
1581         }
1582         if (di->dqb_valid & QIF_BLIMITS) {
1583                 dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
1584                 dm->dqb_bhardlimit = di->dqb_bhardlimit;
1585                 check_blim = 1;
1586         }
1587         if (di->dqb_valid & QIF_INODES) {
1588                 dm->dqb_curinodes = di->dqb_curinodes;
1589                 check_ilim = 1;
1590         }
1591         if (di->dqb_valid & QIF_ILIMITS) {
1592                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
1593                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
1594                 check_ilim = 1;
1595         }
1596         if (di->dqb_valid & QIF_BTIME)
1597                 dm->dqb_btime = di->dqb_btime;
1598         if (di->dqb_valid & QIF_ITIME)
1599                 dm->dqb_itime = di->dqb_itime;
1600
1601         if (check_blim) {
1602                 if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
1603                         dm->dqb_btime = 0;
1604                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1605                 }
1606                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
1607                         dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1608         }
1609         if (check_ilim) {
1610                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
1611                         dm->dqb_itime = 0;
1612                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1613                 }
1614                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
1615                         dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1616         }
1617         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
1618                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
1619         else
1620                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
1621         spin_unlock(&dq_data_lock);
1622         mark_dquot_dirty(dquot);
1623 }
1624
1625 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1626 {
1627         struct dquot *dquot;
1628
1629         down(&sb_dqopt(sb)->dqonoff_sem);
1630         if (!(dquot = dqget(sb, id, type))) {
1631                 up(&sb_dqopt(sb)->dqonoff_sem);
1632                 return -ESRCH;
1633         }
1634         do_set_dqblk(dquot, di);
1635         dqput(dquot);
1636         up(&sb_dqopt(sb)->dqonoff_sem);
1637         return 0;
1638 }
1639
1640 /* Generic routine for getting common part of quota file information */
1641 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1642 {
1643         struct mem_dqinfo *mi;
1644   
1645         down(&sb_dqopt(sb)->dqonoff_sem);
1646         if (!sb_has_quota_enabled(sb, type)) {
1647                 up(&sb_dqopt(sb)->dqonoff_sem);
1648                 return -ESRCH;
1649         }
1650         mi = sb_dqopt(sb)->info + type;
1651         spin_lock(&dq_data_lock);
1652         ii->dqi_bgrace = mi->dqi_bgrace;
1653         ii->dqi_igrace = mi->dqi_igrace;
1654         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
1655         ii->dqi_valid = IIF_ALL;
1656         spin_unlock(&dq_data_lock);
1657         up(&sb_dqopt(sb)->dqonoff_sem);
1658         return 0;
1659 }
1660
1661 /* Generic routine for setting common part of quota file information */
1662 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1663 {
1664         struct mem_dqinfo *mi;
1665
1666         down(&sb_dqopt(sb)->dqonoff_sem);
1667         if (!sb_has_quota_enabled(sb, type)) {
1668                 up(&sb_dqopt(sb)->dqonoff_sem);
1669                 return -ESRCH;
1670         }
1671         mi = sb_dqopt(sb)->info + type;
1672         spin_lock(&dq_data_lock);
1673         if (ii->dqi_valid & IIF_BGRACE)
1674                 mi->dqi_bgrace = ii->dqi_bgrace;
1675         if (ii->dqi_valid & IIF_IGRACE)
1676                 mi->dqi_igrace = ii->dqi_igrace;
1677         if (ii->dqi_valid & IIF_FLAGS)
1678                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
1679         spin_unlock(&dq_data_lock);
1680         mark_info_dirty(sb, type);
1681         /* Force write to disk */
1682         sb->dq_op->write_info(sb, type);
1683         up(&sb_dqopt(sb)->dqonoff_sem);
1684         return 0;
1685 }
1686
1687 struct quotactl_ops vfs_quotactl_ops = {
1688         .quota_on       = vfs_quota_on,
1689         .quota_off      = vfs_quota_off,
1690         .quota_sync     = vfs_quota_sync,
1691         .get_info       = vfs_get_dqinfo,
1692         .set_info       = vfs_set_dqinfo,
1693         .get_dqblk      = vfs_get_dqblk,
1694         .set_dqblk      = vfs_set_dqblk
1695 };
1696
1697 static ctl_table fs_dqstats_table[] = {
1698         {
1699                 .ctl_name       = FS_DQ_LOOKUPS,
1700                 .procname       = "lookups",
1701                 .data           = &dqstats.lookups,
1702                 .maxlen         = sizeof(int),
1703                 .mode           = 0444,
1704                 .proc_handler   = &proc_dointvec,
1705         },
1706         {
1707                 .ctl_name       = FS_DQ_DROPS,
1708                 .procname       = "drops",
1709                 .data           = &dqstats.drops,
1710                 .maxlen         = sizeof(int),
1711                 .mode           = 0444,
1712                 .proc_handler   = &proc_dointvec,
1713         },
1714         {
1715                 .ctl_name       = FS_DQ_READS,
1716                 .procname       = "reads",
1717                 .data           = &dqstats.reads,
1718                 .maxlen         = sizeof(int),
1719                 .mode           = 0444,
1720                 .proc_handler   = &proc_dointvec,
1721         },
1722         {
1723                 .ctl_name       = FS_DQ_WRITES,
1724                 .procname       = "writes",
1725                 .data           = &dqstats.writes,
1726                 .maxlen         = sizeof(int),
1727                 .mode           = 0444,
1728                 .proc_handler   = &proc_dointvec,
1729         },
1730         {
1731                 .ctl_name       = FS_DQ_CACHE_HITS,
1732                 .procname       = "cache_hits",
1733                 .data           = &dqstats.cache_hits,
1734                 .maxlen         = sizeof(int),
1735                 .mode           = 0444,
1736                 .proc_handler   = &proc_dointvec,
1737         },
1738         {
1739                 .ctl_name       = FS_DQ_ALLOCATED,
1740                 .procname       = "allocated_dquots",
1741                 .data           = &dqstats.allocated_dquots,
1742                 .maxlen         = sizeof(int),
1743                 .mode           = 0444,
1744                 .proc_handler   = &proc_dointvec,
1745         },
1746         {
1747                 .ctl_name       = FS_DQ_FREE,
1748                 .procname       = "free_dquots",
1749                 .data           = &dqstats.free_dquots,
1750                 .maxlen         = sizeof(int),
1751                 .mode           = 0444,
1752                 .proc_handler   = &proc_dointvec,
1753         },
1754         {
1755                 .ctl_name       = FS_DQ_SYNCS,
1756                 .procname       = "syncs",
1757                 .data           = &dqstats.syncs,
1758                 .maxlen         = sizeof(int),
1759                 .mode           = 0444,
1760                 .proc_handler   = &proc_dointvec,
1761         },
1762         {
1763                 .ctl_name       = FS_DQ_WARNINGS,
1764                 .procname       = "warnings",
1765                 .data           = &flag_print_warnings,
1766                 .maxlen         = sizeof(int),
1767                 .mode           = 0644,
1768                 .proc_handler   = &proc_dointvec,
1769         },
1770         { .ctl_name = 0 },
1771 };
1772
1773 static ctl_table fs_table[] = {
1774         {
1775                 .ctl_name       = FS_DQSTATS,
1776                 .procname       = "quota",
1777                 .mode           = 0555,
1778                 .child          = fs_dqstats_table,
1779         },
1780         { .ctl_name = 0 },
1781 };
1782
1783 static ctl_table sys_table[] = {
1784         {
1785                 .ctl_name       = CTL_FS,
1786                 .procname       = "fs",
1787                 .mode           = 0555,
1788                 .child          = fs_table,
1789         },
1790         { .ctl_name = 0 },
1791 };
1792
1793 static int __init dquot_init(void)
1794 {
1795         int i;
1796         unsigned long nr_hash, order;
1797
1798         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
1799
1800         register_sysctl_table(sys_table, 0);
1801
1802         dquot_cachep = kmem_cache_create("dquot", 
1803                         sizeof(struct dquot), sizeof(unsigned long) * 4,
1804                         SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
1805                         NULL, NULL);
1806
1807         order = 0;
1808         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
1809         if (!dquot_hash)
1810                 panic("Cannot create dquot hash table");
1811
1812         /* Find power-of-two hlist_heads which can fit into allocation */
1813         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
1814         dq_hash_bits = 0;
1815         do {
1816                 dq_hash_bits++;
1817         } while (nr_hash >> dq_hash_bits);
1818         dq_hash_bits--;
1819
1820         nr_hash = 1UL << dq_hash_bits;
1821         dq_hash_mask = nr_hash - 1;
1822         for (i = 0; i < nr_hash; i++)
1823                 INIT_HLIST_HEAD(dquot_hash + i);
1824
1825         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
1826                         nr_hash, order, (PAGE_SIZE << order));
1827
1828         set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
1829
1830         return 0;
1831 }
1832 module_init(dquot_init);
1833
1834 EXPORT_SYMBOL(register_quota_format);
1835 EXPORT_SYMBOL(unregister_quota_format);
1836 EXPORT_SYMBOL(dqstats);
1837 EXPORT_SYMBOL(dq_data_lock);
1838 EXPORT_SYMBOL(vfs_quota_on);
1839 EXPORT_SYMBOL(vfs_quota_on_mount);
1840 EXPORT_SYMBOL(vfs_quota_off);
1841 EXPORT_SYMBOL(vfs_quota_sync);
1842 EXPORT_SYMBOL(vfs_get_dqinfo);
1843 EXPORT_SYMBOL(vfs_set_dqinfo);
1844 EXPORT_SYMBOL(vfs_get_dqblk);
1845 EXPORT_SYMBOL(vfs_set_dqblk);
1846 EXPORT_SYMBOL(dquot_commit);
1847 EXPORT_SYMBOL(dquot_commit_info);
1848 EXPORT_SYMBOL(dquot_acquire);
1849 EXPORT_SYMBOL(dquot_release);
1850 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
1851 EXPORT_SYMBOL(dquot_initialize);
1852 EXPORT_SYMBOL(dquot_drop);
1853 EXPORT_SYMBOL(dquot_alloc_space);
1854 EXPORT_SYMBOL(dquot_alloc_inode);
1855 EXPORT_SYMBOL(dquot_free_space);
1856 EXPORT_SYMBOL(dquot_free_inode);
1857 EXPORT_SYMBOL(dquot_transfer);