fix sscanf %n match at end of input string
[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/capability.h>
81 #include <linux/quotaops.h>
82 #include <linux/writeback.h> /* for inode_lock, oddly enough.. */
83
84 #include <asm/uaccess.h>
85
86 #define __DQUOT_PARANOIA
87
88 /*
89  * There are two quota SMP locks. dq_list_lock protects all lists with quotas
90  * and quota formats and also dqstats structure containing statistics about the
91  * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
92  * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
93  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
94  * in inode_add_bytes() and inode_sub_bytes().
95  *
96  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
97  *
98  * Note that some things (eg. sb pointer, type, id) doesn't change during
99  * the life of the dquot structure and so needn't to be protected by a lock
100  *
101  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
102  * operation is just reading pointers from inode (or not using them at all) the
103  * read lock is enough. If pointers are altered function must hold write lock
104  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
105  * for altering the flag i_mutex is also needed).  If operation is holding
106  * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
107  * dqonoff_mutex.
108  * This locking assures that:
109  *   a) update/access to dquot pointers in inode is serialized
110  *   b) everyone is guarded against invalidate_dquots()
111  *
112  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
113  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
114  * Currently dquot is locked only when it is being read to memory (or space for
115  * it is being allocated) on the first dqget() and when it is being released on
116  * the last dqput(). The allocation and release oparations are serialized by
117  * the dq_lock and by checking the use count in dquot_release().  Write
118  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
119  * spinlock to internal buffers before writing.
120  *
121  * Lock ordering (including related VFS locks) is the following:
122  *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
123  *   dqio_mutex
124  * i_mutex on quota files is special (it's below dqio_mutex)
125  */
126
127 static DEFINE_SPINLOCK(dq_list_lock);
128 DEFINE_SPINLOCK(dq_data_lock);
129
130 static char *quotatypes[] = INITQFNAMES;
131 static struct quota_format_type *quota_formats; /* List of registered formats */
132 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
133
134 /* SLAB cache for dquot structures */
135 static struct kmem_cache *dquot_cachep;
136
137 int register_quota_format(struct quota_format_type *fmt)
138 {
139         spin_lock(&dq_list_lock);
140         fmt->qf_next = quota_formats;
141         quota_formats = fmt;
142         spin_unlock(&dq_list_lock);
143         return 0;
144 }
145
146 void unregister_quota_format(struct quota_format_type *fmt)
147 {
148         struct quota_format_type **actqf;
149
150         spin_lock(&dq_list_lock);
151         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
152         if (*actqf)
153                 *actqf = (*actqf)->qf_next;
154         spin_unlock(&dq_list_lock);
155 }
156
157 static struct quota_format_type *find_quota_format(int id)
158 {
159         struct quota_format_type *actqf;
160
161         spin_lock(&dq_list_lock);
162         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
163         if (!actqf || !try_module_get(actqf->qf_owner)) {
164                 int qm;
165
166                 spin_unlock(&dq_list_lock);
167                 
168                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
169                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
170                         return NULL;
171
172                 spin_lock(&dq_list_lock);
173                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
174                 if (actqf && !try_module_get(actqf->qf_owner))
175                         actqf = NULL;
176         }
177         spin_unlock(&dq_list_lock);
178         return actqf;
179 }
180
181 static void put_quota_format(struct quota_format_type *fmt)
182 {
183         module_put(fmt->qf_owner);
184 }
185
186 /*
187  * Dquot List Management:
188  * The quota code uses three lists for dquot management: the inuse_list,
189  * free_dquots, and dquot_hash[] array. A single dquot structure may be
190  * on all three lists, depending on its current state.
191  *
192  * All dquots are placed to the end of inuse_list when first created, and this
193  * list is used for invalidate operation, which must look at every dquot.
194  *
195  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
196  * and this list is searched whenever we need an available dquot.  Dquots are
197  * removed from the list as soon as they are used again, and
198  * dqstats.free_dquots gives the number of dquots on the list. When
199  * dquot is invalidated it's completely released from memory.
200  *
201  * Dquots with a specific identity (device, type and id) are placed on
202  * one of the dquot_hash[] hash chains. The provides an efficient search
203  * mechanism to locate a specific dquot.
204  */
205
206 static LIST_HEAD(inuse_list);
207 static LIST_HEAD(free_dquots);
208 static unsigned int dq_hash_bits, dq_hash_mask;
209 static struct hlist_head *dquot_hash;
210
211 struct dqstats dqstats;
212
213 static void dqput(struct dquot *dquot);
214
215 static inline unsigned int
216 hashfn(const struct super_block *sb, unsigned int id, int type)
217 {
218         unsigned long tmp;
219
220         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
221         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
222 }
223
224 /*
225  * Following list functions expect dq_list_lock to be held
226  */
227 static inline void insert_dquot_hash(struct dquot *dquot)
228 {
229         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
230         hlist_add_head(&dquot->dq_hash, head);
231 }
232
233 static inline void remove_dquot_hash(struct dquot *dquot)
234 {
235         hlist_del_init(&dquot->dq_hash);
236 }
237
238 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
239 {
240         struct hlist_node *node;
241         struct dquot *dquot;
242
243         hlist_for_each (node, dquot_hash+hashent) {
244                 dquot = hlist_entry(node, struct dquot, dq_hash);
245                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
246                         return dquot;
247         }
248         return NODQUOT;
249 }
250
251 /* Add a dquot to the tail of the free list */
252 static inline void put_dquot_last(struct dquot *dquot)
253 {
254         list_add_tail(&dquot->dq_free, &free_dquots);
255         dqstats.free_dquots++;
256 }
257
258 static inline void remove_free_dquot(struct dquot *dquot)
259 {
260         if (list_empty(&dquot->dq_free))
261                 return;
262         list_del_init(&dquot->dq_free);
263         dqstats.free_dquots--;
264 }
265
266 static inline void put_inuse(struct dquot *dquot)
267 {
268         /* We add to the back of inuse list so we don't have to restart
269          * when traversing this list and we block */
270         list_add_tail(&dquot->dq_inuse, &inuse_list);
271         dqstats.allocated_dquots++;
272 }
273
274 static inline void remove_inuse(struct dquot *dquot)
275 {
276         dqstats.allocated_dquots--;
277         list_del(&dquot->dq_inuse);
278 }
279 /*
280  * End of list functions needing dq_list_lock
281  */
282
283 static void wait_on_dquot(struct dquot *dquot)
284 {
285         mutex_lock(&dquot->dq_lock);
286         mutex_unlock(&dquot->dq_lock);
287 }
288
289 #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
290
291 int dquot_mark_dquot_dirty(struct dquot *dquot)
292 {
293         spin_lock(&dq_list_lock);
294         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
295                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
296                                 info[dquot->dq_type].dqi_dirty_list);
297         spin_unlock(&dq_list_lock);
298         return 0;
299 }
300
301 /* This function needs dq_list_lock */
302 static inline int clear_dquot_dirty(struct dquot *dquot)
303 {
304         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
305                 return 0;
306         list_del_init(&dquot->dq_dirty);
307         return 1;
308 }
309
310 void mark_info_dirty(struct super_block *sb, int type)
311 {
312         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
313 }
314 EXPORT_SYMBOL(mark_info_dirty);
315
316 /*
317  *      Read dquot from disk and alloc space for it
318  */
319
320 int dquot_acquire(struct dquot *dquot)
321 {
322         int ret = 0, ret2 = 0;
323         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
324
325         mutex_lock(&dquot->dq_lock);
326         mutex_lock(&dqopt->dqio_mutex);
327         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
328                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
329         if (ret < 0)
330                 goto out_iolock;
331         set_bit(DQ_READ_B, &dquot->dq_flags);
332         /* Instantiate dquot if needed */
333         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
334                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
335                 /* Write the info if needed */
336                 if (info_dirty(&dqopt->info[dquot->dq_type]))
337                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
338                 if (ret < 0)
339                         goto out_iolock;
340                 if (ret2 < 0) {
341                         ret = ret2;
342                         goto out_iolock;
343                 }
344         }
345         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
346 out_iolock:
347         mutex_unlock(&dqopt->dqio_mutex);
348         mutex_unlock(&dquot->dq_lock);
349         return ret;
350 }
351
352 /*
353  *      Write dquot to disk
354  */
355 int dquot_commit(struct dquot *dquot)
356 {
357         int ret = 0, ret2 = 0;
358         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
359
360         mutex_lock(&dqopt->dqio_mutex);
361         spin_lock(&dq_list_lock);
362         if (!clear_dquot_dirty(dquot)) {
363                 spin_unlock(&dq_list_lock);
364                 goto out_sem;
365         }
366         spin_unlock(&dq_list_lock);
367         /* Inactive dquot can be only if there was error during read/init
368          * => we have better not writing it */
369         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
370                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
371                 if (info_dirty(&dqopt->info[dquot->dq_type]))
372                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
373                 if (ret >= 0)
374                         ret = ret2;
375         }
376 out_sem:
377         mutex_unlock(&dqopt->dqio_mutex);
378         return ret;
379 }
380
381 /*
382  *      Release dquot
383  */
384 int dquot_release(struct dquot *dquot)
385 {
386         int ret = 0, ret2 = 0;
387         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
388
389         mutex_lock(&dquot->dq_lock);
390         /* Check whether we are not racing with some other dqget() */
391         if (atomic_read(&dquot->dq_count) > 1)
392                 goto out_dqlock;
393         mutex_lock(&dqopt->dqio_mutex);
394         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
395                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
396                 /* Write the info */
397                 if (info_dirty(&dqopt->info[dquot->dq_type]))
398                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
399                 if (ret >= 0)
400                         ret = ret2;
401         }
402         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
403         mutex_unlock(&dqopt->dqio_mutex);
404 out_dqlock:
405         mutex_unlock(&dquot->dq_lock);
406         return ret;
407 }
408
409 /* Invalidate all dquots on the list. Note that this function is called after
410  * quota is disabled and pointers from inodes removed so there cannot be new
411  * quota users. There can still be some users of quotas due to inodes being
412  * just deleted or pruned by prune_icache() (those are not attached to any
413  * list). We have to wait for such users.
414  */
415 static void invalidate_dquots(struct super_block *sb, int type)
416 {
417         struct dquot *dquot, *tmp;
418
419 restart:
420         spin_lock(&dq_list_lock);
421         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
422                 if (dquot->dq_sb != sb)
423                         continue;
424                 if (dquot->dq_type != type)
425                         continue;
426                 /* Wait for dquot users */
427                 if (atomic_read(&dquot->dq_count)) {
428                         DEFINE_WAIT(wait);
429
430                         atomic_inc(&dquot->dq_count);
431                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
432                                         TASK_UNINTERRUPTIBLE);
433                         spin_unlock(&dq_list_lock);
434                         /* Once dqput() wakes us up, we know it's time to free
435                          * the dquot.
436                          * IMPORTANT: we rely on the fact that there is always
437                          * at most one process waiting for dquot to free.
438                          * Otherwise dq_count would be > 1 and we would never
439                          * wake up.
440                          */
441                         if (atomic_read(&dquot->dq_count) > 1)
442                                 schedule();
443                         finish_wait(&dquot->dq_wait_unused, &wait);
444                         dqput(dquot);
445                         /* At this moment dquot() need not exist (it could be
446                          * reclaimed by prune_dqcache(). Hence we must
447                          * restart. */
448                         goto restart;
449                 }
450                 /*
451                  * Quota now has no users and it has been written on last
452                  * dqput()
453                  */
454                 remove_dquot_hash(dquot);
455                 remove_free_dquot(dquot);
456                 remove_inuse(dquot);
457                 kmem_cache_free(dquot_cachep, dquot);
458         }
459         spin_unlock(&dq_list_lock);
460 }
461
462 int vfs_quota_sync(struct super_block *sb, int type)
463 {
464         struct list_head *dirty;
465         struct dquot *dquot;
466         struct quota_info *dqopt = sb_dqopt(sb);
467         int cnt;
468
469         mutex_lock(&dqopt->dqonoff_mutex);
470         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
471                 if (type != -1 && cnt != type)
472                         continue;
473                 if (!sb_has_quota_enabled(sb, cnt))
474                         continue;
475                 spin_lock(&dq_list_lock);
476                 dirty = &dqopt->info[cnt].dqi_dirty_list;
477                 while (!list_empty(dirty)) {
478                         dquot = list_entry(dirty->next, struct dquot, dq_dirty);
479                         /* Dirty and inactive can be only bad dquot... */
480                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
481                                 clear_dquot_dirty(dquot);
482                                 continue;
483                         }
484                         /* Now we have active dquot from which someone is
485                          * holding reference so we can safely just increase
486                          * use count */
487                         atomic_inc(&dquot->dq_count);
488                         dqstats.lookups++;
489                         spin_unlock(&dq_list_lock);
490                         sb->dq_op->write_dquot(dquot);
491                         dqput(dquot);
492                         spin_lock(&dq_list_lock);
493                 }
494                 spin_unlock(&dq_list_lock);
495         }
496
497         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
498                 if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
499                         && info_dirty(&dqopt->info[cnt]))
500                         sb->dq_op->write_info(sb, cnt);
501         spin_lock(&dq_list_lock);
502         dqstats.syncs++;
503         spin_unlock(&dq_list_lock);
504         mutex_unlock(&dqopt->dqonoff_mutex);
505
506         return 0;
507 }
508
509 /* Free unused dquots from cache */
510 static void prune_dqcache(int count)
511 {
512         struct list_head *head;
513         struct dquot *dquot;
514
515         head = free_dquots.prev;
516         while (head != &free_dquots && count) {
517                 dquot = list_entry(head, struct dquot, dq_free);
518                 remove_dquot_hash(dquot);
519                 remove_free_dquot(dquot);
520                 remove_inuse(dquot);
521                 kmem_cache_free(dquot_cachep, dquot);
522                 count--;
523                 head = free_dquots.prev;
524         }
525 }
526
527 /*
528  * This is called from kswapd when we think we need some
529  * more memory
530  */
531
532 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
533 {
534         if (nr) {
535                 spin_lock(&dq_list_lock);
536                 prune_dqcache(nr);
537                 spin_unlock(&dq_list_lock);
538         }
539         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
540 }
541
542 /*
543  * Put reference to dquot
544  * NOTE: If you change this function please check whether dqput_blocks() works right...
545  * MUST be called with either dqptr_sem or dqonoff_mutex held
546  */
547 static void dqput(struct dquot *dquot)
548 {
549         if (!dquot)
550                 return;
551 #ifdef __DQUOT_PARANOIA
552         if (!atomic_read(&dquot->dq_count)) {
553                 printk("VFS: dqput: trying to free free dquot\n");
554                 printk("VFS: device %s, dquot of %s %d\n",
555                         dquot->dq_sb->s_id,
556                         quotatypes[dquot->dq_type],
557                         dquot->dq_id);
558                 BUG();
559         }
560 #endif
561         
562         spin_lock(&dq_list_lock);
563         dqstats.drops++;
564         spin_unlock(&dq_list_lock);
565 we_slept:
566         spin_lock(&dq_list_lock);
567         if (atomic_read(&dquot->dq_count) > 1) {
568                 /* We have more than one user... nothing to do */
569                 atomic_dec(&dquot->dq_count);
570                 /* Releasing dquot during quotaoff phase? */
571                 if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
572                     atomic_read(&dquot->dq_count) == 1)
573                         wake_up(&dquot->dq_wait_unused);
574                 spin_unlock(&dq_list_lock);
575                 return;
576         }
577         /* Need to release dquot? */
578         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
579                 spin_unlock(&dq_list_lock);
580                 /* Commit dquot before releasing */
581                 dquot->dq_sb->dq_op->write_dquot(dquot);
582                 goto we_slept;
583         }
584         /* Clear flag in case dquot was inactive (something bad happened) */
585         clear_dquot_dirty(dquot);
586         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
587                 spin_unlock(&dq_list_lock);
588                 dquot->dq_sb->dq_op->release_dquot(dquot);
589                 goto we_slept;
590         }
591         atomic_dec(&dquot->dq_count);
592 #ifdef __DQUOT_PARANOIA
593         /* sanity check */
594         BUG_ON(!list_empty(&dquot->dq_free));
595 #endif
596         put_dquot_last(dquot);
597         spin_unlock(&dq_list_lock);
598 }
599
600 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
601 {
602         struct dquot *dquot;
603
604         dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
605         if(!dquot)
606                 return NODQUOT;
607
608         mutex_init(&dquot->dq_lock);
609         INIT_LIST_HEAD(&dquot->dq_free);
610         INIT_LIST_HEAD(&dquot->dq_inuse);
611         INIT_HLIST_NODE(&dquot->dq_hash);
612         INIT_LIST_HEAD(&dquot->dq_dirty);
613         init_waitqueue_head(&dquot->dq_wait_unused);
614         dquot->dq_sb = sb;
615         dquot->dq_type = type;
616         atomic_set(&dquot->dq_count, 1);
617
618         return dquot;
619 }
620
621 /*
622  * Get reference to dquot
623  * MUST be called with either dqptr_sem or dqonoff_mutex held
624  */
625 static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
626 {
627         unsigned int hashent = hashfn(sb, id, type);
628         struct dquot *dquot, *empty = NODQUOT;
629
630         if (!sb_has_quota_enabled(sb, type))
631                 return NODQUOT;
632 we_slept:
633         spin_lock(&dq_list_lock);
634         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
635                 if (empty == NODQUOT) {
636                         spin_unlock(&dq_list_lock);
637                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
638                                 schedule();     /* Try to wait for a moment... */
639                         goto we_slept;
640                 }
641                 dquot = empty;
642                 dquot->dq_id = id;
643                 /* all dquots go on the inuse_list */
644                 put_inuse(dquot);
645                 /* hash it first so it can be found */
646                 insert_dquot_hash(dquot);
647                 dqstats.lookups++;
648                 spin_unlock(&dq_list_lock);
649         } else {
650                 if (!atomic_read(&dquot->dq_count))
651                         remove_free_dquot(dquot);
652                 atomic_inc(&dquot->dq_count);
653                 dqstats.cache_hits++;
654                 dqstats.lookups++;
655                 spin_unlock(&dq_list_lock);
656                 if (empty)
657                         kmem_cache_free(dquot_cachep, empty);
658         }
659         /* Wait for dq_lock - after this we know that either dquot_release() is already
660          * finished or it will be canceled due to dq_count > 1 test */
661         wait_on_dquot(dquot);
662         /* Read the dquot and instantiate it (everything done only if needed) */
663         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
664                 dqput(dquot);
665                 return NODQUOT;
666         }
667 #ifdef __DQUOT_PARANOIA
668         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
669 #endif
670
671         return dquot;
672 }
673
674 static int dqinit_needed(struct inode *inode, int type)
675 {
676         int cnt;
677
678         if (IS_NOQUOTA(inode))
679                 return 0;
680         if (type != -1)
681                 return inode->i_dquot[type] == NODQUOT;
682         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
683                 if (inode->i_dquot[cnt] == NODQUOT)
684                         return 1;
685         return 0;
686 }
687
688 /* This routine is guarded by dqonoff_mutex mutex */
689 static void add_dquot_ref(struct super_block *sb, int type)
690 {
691         struct inode *inode;
692
693 restart:
694         spin_lock(&inode_lock);
695         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
696                 if (!atomic_read(&inode->i_writecount))
697                         continue;
698                 if (!dqinit_needed(inode, type))
699                         continue;
700                 if (inode->i_state & (I_FREEING|I_WILL_FREE))
701                         continue;
702
703                 __iget(inode);
704                 spin_unlock(&inode_lock);
705
706                 sb->dq_op->initialize(inode, type);
707                 iput(inode);
708                 /* As we may have blocked we had better restart... */
709                 goto restart;
710         }
711         spin_unlock(&inode_lock);
712 }
713
714 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
715 static inline int dqput_blocks(struct dquot *dquot)
716 {
717         if (atomic_read(&dquot->dq_count) <= 1)
718                 return 1;
719         return 0;
720 }
721
722 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
723 /* We can't race with anybody because we hold dqptr_sem for writing... */
724 int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
725 {
726         struct dquot *dquot = inode->i_dquot[type];
727
728         inode->i_dquot[type] = NODQUOT;
729         if (dquot != NODQUOT) {
730                 if (dqput_blocks(dquot)) {
731 #ifdef __DQUOT_PARANOIA
732                         if (atomic_read(&dquot->dq_count) != 1)
733                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
734 #endif
735                         spin_lock(&dq_list_lock);
736                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
737                         spin_unlock(&dq_list_lock);
738                         return 1;
739                 }
740                 else
741                         dqput(dquot);   /* We have guaranteed we won't block */
742         }
743         return 0;
744 }
745
746 /* Free list of dquots - called from inode.c */
747 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
748 static void put_dquot_list(struct list_head *tofree_head)
749 {
750         struct list_head *act_head;
751         struct dquot *dquot;
752
753         act_head = tofree_head->next;
754         /* So now we have dquots on the list... Just free them */
755         while (act_head != tofree_head) {
756                 dquot = list_entry(act_head, struct dquot, dq_free);
757                 act_head = act_head->next;
758                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
759                 dqput(dquot);
760         }
761 }
762
763 static void remove_dquot_ref(struct super_block *sb, int type,
764                 struct list_head *tofree_head)
765 {
766         struct inode *inode;
767
768         spin_lock(&inode_lock);
769         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
770                 if (!IS_NOQUOTA(inode))
771                         remove_inode_dquot_ref(inode, type, tofree_head);
772         }
773         spin_unlock(&inode_lock);
774 }
775
776 /* Gather all references from inodes and drop them */
777 static void drop_dquot_ref(struct super_block *sb, int type)
778 {
779         LIST_HEAD(tofree_head);
780
781         if (sb->dq_op) {
782                 down_write(&sb_dqopt(sb)->dqptr_sem);
783                 remove_dquot_ref(sb, type, &tofree_head);
784                 up_write(&sb_dqopt(sb)->dqptr_sem);
785                 put_dquot_list(&tofree_head);
786         }
787 }
788
789 static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
790 {
791         dquot->dq_dqb.dqb_curinodes += number;
792 }
793
794 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
795 {
796         dquot->dq_dqb.dqb_curspace += number;
797 }
798
799 static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
800 {
801         if (dquot->dq_dqb.dqb_curinodes > number)
802                 dquot->dq_dqb.dqb_curinodes -= number;
803         else
804                 dquot->dq_dqb.dqb_curinodes = 0;
805         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
806                 dquot->dq_dqb.dqb_itime = (time_t) 0;
807         clear_bit(DQ_INODES_B, &dquot->dq_flags);
808 }
809
810 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
811 {
812         if (dquot->dq_dqb.dqb_curspace > number)
813                 dquot->dq_dqb.dqb_curspace -= number;
814         else
815                 dquot->dq_dqb.dqb_curspace = 0;
816         if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
817                 dquot->dq_dqb.dqb_btime = (time_t) 0;
818         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
819 }
820
821 static int flag_print_warnings = 1;
822
823 static inline int need_print_warning(struct dquot *dquot)
824 {
825         if (!flag_print_warnings)
826                 return 0;
827
828         switch (dquot->dq_type) {
829                 case USRQUOTA:
830                         return current->fsuid == dquot->dq_id;
831                 case GRPQUOTA:
832                         return in_group_p(dquot->dq_id);
833         }
834         return 0;
835 }
836
837 /* Values of warnings */
838 #define NOWARN 0
839 #define IHARDWARN 1
840 #define ISOFTLONGWARN 2
841 #define ISOFTWARN 3
842 #define BHARDWARN 4
843 #define BSOFTLONGWARN 5
844 #define BSOFTWARN 6
845
846 /* Print warning to user which exceeded quota */
847 static void print_warning(struct dquot *dquot, const char warntype)
848 {
849         char *msg = NULL;
850         struct tty_struct *tty;
851         int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
852           ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
853
854         if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
855                 return;
856
857         mutex_lock(&tty_mutex);
858         tty = get_current_tty();
859         if (!tty)
860                 goto out_lock;
861         tty_write_message(tty, dquot->dq_sb->s_id);
862         if (warntype == ISOFTWARN || warntype == BSOFTWARN)
863                 tty_write_message(tty, ": warning, ");
864         else
865                 tty_write_message(tty, ": write failed, ");
866         tty_write_message(tty, quotatypes[dquot->dq_type]);
867         switch (warntype) {
868                 case IHARDWARN:
869                         msg = " file limit reached.\r\n";
870                         break;
871                 case ISOFTLONGWARN:
872                         msg = " file quota exceeded too long.\r\n";
873                         break;
874                 case ISOFTWARN:
875                         msg = " file quota exceeded.\r\n";
876                         break;
877                 case BHARDWARN:
878                         msg = " block limit reached.\r\n";
879                         break;
880                 case BSOFTLONGWARN:
881                         msg = " block quota exceeded too long.\r\n";
882                         break;
883                 case BSOFTWARN:
884                         msg = " block quota exceeded.\r\n";
885                         break;
886         }
887         tty_write_message(tty, msg);
888 out_lock:
889         mutex_unlock(&tty_mutex);
890 }
891
892 static inline void flush_warnings(struct dquot **dquots, char *warntype)
893 {
894         int i;
895
896         for (i = 0; i < MAXQUOTAS; i++)
897                 if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
898                         print_warning(dquots[i], warntype[i]);
899 }
900
901 static inline char ignore_hardlimit(struct dquot *dquot)
902 {
903         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
904
905         return capable(CAP_SYS_RESOURCE) &&
906             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
907 }
908
909 /* needs dq_data_lock */
910 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
911 {
912         *warntype = NOWARN;
913         if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
914                 return QUOTA_OK;
915
916         if (dquot->dq_dqb.dqb_ihardlimit &&
917            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
918             !ignore_hardlimit(dquot)) {
919                 *warntype = IHARDWARN;
920                 return NO_QUOTA;
921         }
922
923         if (dquot->dq_dqb.dqb_isoftlimit &&
924            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
925             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
926             !ignore_hardlimit(dquot)) {
927                 *warntype = ISOFTLONGWARN;
928                 return NO_QUOTA;
929         }
930
931         if (dquot->dq_dqb.dqb_isoftlimit &&
932            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
933             dquot->dq_dqb.dqb_itime == 0) {
934                 *warntype = ISOFTWARN;
935                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
936         }
937
938         return QUOTA_OK;
939 }
940
941 /* needs dq_data_lock */
942 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
943 {
944         *warntype = 0;
945         if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
946                 return QUOTA_OK;
947
948         if (dquot->dq_dqb.dqb_bhardlimit &&
949            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
950             !ignore_hardlimit(dquot)) {
951                 if (!prealloc)
952                         *warntype = BHARDWARN;
953                 return NO_QUOTA;
954         }
955
956         if (dquot->dq_dqb.dqb_bsoftlimit &&
957            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
958             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
959             !ignore_hardlimit(dquot)) {
960                 if (!prealloc)
961                         *warntype = BSOFTLONGWARN;
962                 return NO_QUOTA;
963         }
964
965         if (dquot->dq_dqb.dqb_bsoftlimit &&
966            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
967             dquot->dq_dqb.dqb_btime == 0) {
968                 if (!prealloc) {
969                         *warntype = BSOFTWARN;
970                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
971                 }
972                 else
973                         /*
974                          * We don't allow preallocation to exceed softlimit so exceeding will
975                          * be always printed
976                          */
977                         return NO_QUOTA;
978         }
979
980         return QUOTA_OK;
981 }
982
983 /*
984  *      Initialize quota pointers in inode
985  *      Transaction must be started at entry
986  */
987 int dquot_initialize(struct inode *inode, int type)
988 {
989         unsigned int id = 0;
990         int cnt, ret = 0;
991
992         /* First test before acquiring mutex - solves deadlocks when we
993          * re-enter the quota code and are already holding the mutex */
994         if (IS_NOQUOTA(inode))
995                 return 0;
996         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
997         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
998         if (IS_NOQUOTA(inode))
999                 goto out_err;
1000         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1001                 if (type != -1 && cnt != type)
1002                         continue;
1003                 if (inode->i_dquot[cnt] == NODQUOT) {
1004                         switch (cnt) {
1005                                 case USRQUOTA:
1006                                         id = inode->i_uid;
1007                                         break;
1008                                 case GRPQUOTA:
1009                                         id = inode->i_gid;
1010                                         break;
1011                         }
1012                         inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
1013                 }
1014         }
1015 out_err:
1016         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1017         return ret;
1018 }
1019
1020 /*
1021  *      Release all quotas referenced by inode
1022  *      Transaction must be started at an entry
1023  */
1024 int dquot_drop(struct inode *inode)
1025 {
1026         int cnt;
1027
1028         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1029         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1030                 if (inode->i_dquot[cnt] != NODQUOT) {
1031                         dqput(inode->i_dquot[cnt]);
1032                         inode->i_dquot[cnt] = NODQUOT;
1033                 }
1034         }
1035         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1036         return 0;
1037 }
1038
1039 /*
1040  * Following four functions update i_blocks+i_bytes fields and
1041  * quota information (together with appropriate checks)
1042  * NOTE: We absolutely rely on the fact that caller dirties
1043  * the inode (usually macros in quotaops.h care about this) and
1044  * holds a handle for the current transaction so that dquot write and
1045  * inode write go into the same transaction.
1046  */
1047
1048 /*
1049  * This operation can block, but only after everything is updated
1050  */
1051 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1052 {
1053         int cnt, ret = NO_QUOTA;
1054         char warntype[MAXQUOTAS];
1055
1056         /* First test before acquiring mutex - solves deadlocks when we
1057          * re-enter the quota code and are already holding the mutex */
1058         if (IS_NOQUOTA(inode)) {
1059 out_add:
1060                 inode_add_bytes(inode, number);
1061                 return QUOTA_OK;
1062         }
1063         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1064                 warntype[cnt] = NOWARN;
1065
1066         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1067         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1068                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1069                 goto out_add;
1070         }
1071         spin_lock(&dq_data_lock);
1072         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1073                 if (inode->i_dquot[cnt] == NODQUOT)
1074                         continue;
1075                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1076                         goto warn_put_all;
1077         }
1078         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1079                 if (inode->i_dquot[cnt] == NODQUOT)
1080                         continue;
1081                 dquot_incr_space(inode->i_dquot[cnt], number);
1082         }
1083         inode_add_bytes(inode, number);
1084         ret = QUOTA_OK;
1085 warn_put_all:
1086         spin_unlock(&dq_data_lock);
1087         if (ret == QUOTA_OK)
1088                 /* Dirtify all the dquots - this can block when journalling */
1089                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1090                         if (inode->i_dquot[cnt])
1091                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1092         flush_warnings(inode->i_dquot, warntype);
1093         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1094         return ret;
1095 }
1096
1097 /*
1098  * This operation can block, but only after everything is updated
1099  */
1100 int dquot_alloc_inode(const struct inode *inode, unsigned long number)
1101 {
1102         int cnt, ret = NO_QUOTA;
1103         char warntype[MAXQUOTAS];
1104
1105         /* First test before acquiring mutex - solves deadlocks when we
1106          * re-enter the quota code and are already holding the mutex */
1107         if (IS_NOQUOTA(inode))
1108                 return QUOTA_OK;
1109         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1110                 warntype[cnt] = NOWARN;
1111         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1112         if (IS_NOQUOTA(inode)) {
1113                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1114                 return QUOTA_OK;
1115         }
1116         spin_lock(&dq_data_lock);
1117         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1118                 if (inode->i_dquot[cnt] == NODQUOT)
1119                         continue;
1120                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1121                         goto warn_put_all;
1122         }
1123
1124         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1125                 if (inode->i_dquot[cnt] == NODQUOT)
1126                         continue;
1127                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1128         }
1129         ret = QUOTA_OK;
1130 warn_put_all:
1131         spin_unlock(&dq_data_lock);
1132         if (ret == QUOTA_OK)
1133                 /* Dirtify all the dquots - this can block when journalling */
1134                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1135                         if (inode->i_dquot[cnt])
1136                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1137         flush_warnings((struct dquot **)inode->i_dquot, warntype);
1138         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1139         return ret;
1140 }
1141
1142 /*
1143  * This operation can block, but only after everything is updated
1144  */
1145 int dquot_free_space(struct inode *inode, qsize_t number)
1146 {
1147         unsigned int cnt;
1148
1149         /* First test before acquiring mutex - solves deadlocks when we
1150          * re-enter the quota code and are already holding the mutex */
1151         if (IS_NOQUOTA(inode)) {
1152 out_sub:
1153                 inode_sub_bytes(inode, number);
1154                 return QUOTA_OK;
1155         }
1156         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1157         /* Now recheck reliably when holding dqptr_sem */
1158         if (IS_NOQUOTA(inode)) {
1159                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1160                 goto out_sub;
1161         }
1162         spin_lock(&dq_data_lock);
1163         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1164                 if (inode->i_dquot[cnt] == NODQUOT)
1165                         continue;
1166                 dquot_decr_space(inode->i_dquot[cnt], number);
1167         }
1168         inode_sub_bytes(inode, number);
1169         spin_unlock(&dq_data_lock);
1170         /* Dirtify all the dquots - this can block when journalling */
1171         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1172                 if (inode->i_dquot[cnt])
1173                         mark_dquot_dirty(inode->i_dquot[cnt]);
1174         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1175         return QUOTA_OK;
1176 }
1177
1178 /*
1179  * This operation can block, but only after everything is updated
1180  */
1181 int dquot_free_inode(const struct inode *inode, unsigned long number)
1182 {
1183         unsigned int cnt;
1184
1185         /* First test before acquiring mutex - solves deadlocks when we
1186          * re-enter the quota code and are already holding the mutex */
1187         if (IS_NOQUOTA(inode))
1188                 return QUOTA_OK;
1189         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1190         /* Now recheck reliably when holding dqptr_sem */
1191         if (IS_NOQUOTA(inode)) {
1192                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1193                 return QUOTA_OK;
1194         }
1195         spin_lock(&dq_data_lock);
1196         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1197                 if (inode->i_dquot[cnt] == NODQUOT)
1198                         continue;
1199                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1200         }
1201         spin_unlock(&dq_data_lock);
1202         /* Dirtify all the dquots - this can block when journalling */
1203         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1204                 if (inode->i_dquot[cnt])
1205                         mark_dquot_dirty(inode->i_dquot[cnt]);
1206         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1207         return QUOTA_OK;
1208 }
1209
1210 /*
1211  * Transfer the number of inode and blocks from one diskquota to an other.
1212  *
1213  * This operation can block, but only after everything is updated
1214  * A transaction must be started when entering this function.
1215  */
1216 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1217 {
1218         qsize_t space;
1219         struct dquot *transfer_from[MAXQUOTAS];
1220         struct dquot *transfer_to[MAXQUOTAS];
1221         int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
1222             chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
1223         char warntype[MAXQUOTAS];
1224
1225         /* First test before acquiring mutex - solves deadlocks when we
1226          * re-enter the quota code and are already holding the mutex */
1227         if (IS_NOQUOTA(inode))
1228                 return QUOTA_OK;
1229         /* Clear the arrays */
1230         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1231                 transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
1232                 warntype[cnt] = NOWARN;
1233         }
1234         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1235         /* Now recheck reliably when holding dqptr_sem */
1236         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1237                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1238                 return QUOTA_OK;
1239         }
1240         /* First build the transfer_to list - here we can block on
1241          * reading/instantiating of dquots.  We know that the transaction for
1242          * us was already started so we don't violate lock ranking here */
1243         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1244                 switch (cnt) {
1245                         case USRQUOTA:
1246                                 if (!chuid)
1247                                         continue;
1248                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1249                                 break;
1250                         case GRPQUOTA:
1251                                 if (!chgid)
1252                                         continue;
1253                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1254                                 break;
1255                 }
1256         }
1257         spin_lock(&dq_data_lock);
1258         space = inode_get_bytes(inode);
1259         /* Build the transfer_from list and check the limits */
1260         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1261                 if (transfer_to[cnt] == NODQUOT)
1262                         continue;
1263                 transfer_from[cnt] = inode->i_dquot[cnt];
1264                 if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
1265                     check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
1266                         goto warn_put_all;
1267         }
1268
1269         /*
1270          * Finally perform the needed transfer from transfer_from to transfer_to
1271          */
1272         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1273                 /*
1274                  * Skip changes for same uid or gid or for turned off quota-type.
1275                  */
1276                 if (transfer_to[cnt] == NODQUOT)
1277                         continue;
1278
1279                 /* Due to IO error we might not have transfer_from[] structure */
1280                 if (transfer_from[cnt]) {
1281                         dquot_decr_inodes(transfer_from[cnt], 1);
1282                         dquot_decr_space(transfer_from[cnt], space);
1283                 }
1284
1285                 dquot_incr_inodes(transfer_to[cnt], 1);
1286                 dquot_incr_space(transfer_to[cnt], space);
1287
1288                 inode->i_dquot[cnt] = transfer_to[cnt];
1289         }
1290         ret = QUOTA_OK;
1291 warn_put_all:
1292         spin_unlock(&dq_data_lock);
1293         /* Dirtify all the dquots - this can block when journalling */
1294         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1295                 if (transfer_from[cnt])
1296                         mark_dquot_dirty(transfer_from[cnt]);
1297                 if (transfer_to[cnt])
1298                         mark_dquot_dirty(transfer_to[cnt]);
1299         }
1300         flush_warnings(transfer_to, warntype);
1301         
1302         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1303                 if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
1304                         dqput(transfer_from[cnt]);
1305                 if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
1306                         dqput(transfer_to[cnt]);
1307         }
1308         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1309         return ret;
1310 }
1311
1312 /*
1313  * Write info of quota file to disk
1314  */
1315 int dquot_commit_info(struct super_block *sb, int type)
1316 {
1317         int ret;
1318         struct quota_info *dqopt = sb_dqopt(sb);
1319
1320         mutex_lock(&dqopt->dqio_mutex);
1321         ret = dqopt->ops[type]->write_file_info(sb, type);
1322         mutex_unlock(&dqopt->dqio_mutex);
1323         return ret;
1324 }
1325
1326 /*
1327  * Definitions of diskquota operations.
1328  */
1329 struct dquot_operations dquot_operations = {
1330         .initialize     = dquot_initialize,
1331         .drop           = dquot_drop,
1332         .alloc_space    = dquot_alloc_space,
1333         .alloc_inode    = dquot_alloc_inode,
1334         .free_space     = dquot_free_space,
1335         .free_inode     = dquot_free_inode,
1336         .transfer       = dquot_transfer,
1337         .write_dquot    = dquot_commit,
1338         .acquire_dquot  = dquot_acquire,
1339         .release_dquot  = dquot_release,
1340         .mark_dirty     = dquot_mark_dquot_dirty,
1341         .write_info     = dquot_commit_info
1342 };
1343
1344 static inline void set_enable_flags(struct quota_info *dqopt, int type)
1345 {
1346         switch (type) {
1347                 case USRQUOTA:
1348                         dqopt->flags |= DQUOT_USR_ENABLED;
1349                         break;
1350                 case GRPQUOTA:
1351                         dqopt->flags |= DQUOT_GRP_ENABLED;
1352                         break;
1353         }
1354 }
1355
1356 static inline void reset_enable_flags(struct quota_info *dqopt, int type)
1357 {
1358         switch (type) {
1359                 case USRQUOTA:
1360                         dqopt->flags &= ~DQUOT_USR_ENABLED;
1361                         break;
1362                 case GRPQUOTA:
1363                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
1364                         break;
1365         }
1366 }
1367
1368 /*
1369  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1370  */
1371 int vfs_quota_off(struct super_block *sb, int type)
1372 {
1373         int cnt;
1374         struct quota_info *dqopt = sb_dqopt(sb);
1375         struct inode *toputinode[MAXQUOTAS];
1376
1377         /* We need to serialize quota_off() for device */
1378         mutex_lock(&dqopt->dqonoff_mutex);
1379         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1380                 toputinode[cnt] = NULL;
1381                 if (type != -1 && cnt != type)
1382                         continue;
1383                 if (!sb_has_quota_enabled(sb, cnt))
1384                         continue;
1385                 reset_enable_flags(dqopt, cnt);
1386
1387                 /* Note: these are blocking operations */
1388                 drop_dquot_ref(sb, cnt);
1389                 invalidate_dquots(sb, cnt);
1390                 /*
1391                  * Now all dquots should be invalidated, all writes done so we should be only
1392                  * users of the info. No locks needed.
1393                  */
1394                 if (info_dirty(&dqopt->info[cnt]))
1395                         sb->dq_op->write_info(sb, cnt);
1396                 if (dqopt->ops[cnt]->free_file_info)
1397                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1398                 put_quota_format(dqopt->info[cnt].dqi_format);
1399
1400                 toputinode[cnt] = dqopt->files[cnt];
1401                 dqopt->files[cnt] = NULL;
1402                 dqopt->info[cnt].dqi_flags = 0;
1403                 dqopt->info[cnt].dqi_igrace = 0;
1404                 dqopt->info[cnt].dqi_bgrace = 0;
1405                 dqopt->ops[cnt] = NULL;
1406         }
1407         mutex_unlock(&dqopt->dqonoff_mutex);
1408         /* Sync the superblock so that buffers with quota data are written to
1409          * disk (and so userspace sees correct data afterwards). */
1410         if (sb->s_op->sync_fs)
1411                 sb->s_op->sync_fs(sb, 1);
1412         sync_blockdev(sb->s_bdev);
1413         /* Now the quota files are just ordinary files and we can set the
1414          * inode flags back. Moreover we discard the pagecache so that
1415          * userspace sees the writes we did bypassing the pagecache. We
1416          * must also discard the blockdev buffers so that we see the
1417          * changes done by userspace on the next quotaon() */
1418         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1419                 if (toputinode[cnt]) {
1420                         mutex_lock(&dqopt->dqonoff_mutex);
1421                         /* If quota was reenabled in the meantime, we have
1422                          * nothing to do */
1423                         if (!sb_has_quota_enabled(sb, cnt)) {
1424                                 mutex_lock(&toputinode[cnt]->i_mutex);
1425                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1426                                   S_NOATIME | S_NOQUOTA);
1427                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1428                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1429                                 mark_inode_dirty(toputinode[cnt]);
1430                                 iput(toputinode[cnt]);
1431                         }
1432                         mutex_unlock(&dqopt->dqonoff_mutex);
1433                 }
1434         if (sb->s_bdev)
1435                 invalidate_bdev(sb->s_bdev);
1436         return 0;
1437 }
1438
1439 /*
1440  *      Turn quotas on on a device
1441  */
1442
1443 /* Helper function when we already have the inode */
1444 static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
1445 {
1446         struct quota_format_type *fmt = find_quota_format(format_id);
1447         struct super_block *sb = inode->i_sb;
1448         struct quota_info *dqopt = sb_dqopt(sb);
1449         int error;
1450         int oldflags = -1;
1451
1452         if (!fmt)
1453                 return -ESRCH;
1454         if (!S_ISREG(inode->i_mode)) {
1455                 error = -EACCES;
1456                 goto out_fmt;
1457         }
1458         if (IS_RDONLY(inode)) {
1459                 error = -EROFS;
1460                 goto out_fmt;
1461         }
1462         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1463                 error = -EINVAL;
1464                 goto out_fmt;
1465         }
1466
1467         /* As we bypass the pagecache we must now flush the inode so that
1468          * we see all the changes from userspace... */
1469         write_inode_now(inode, 1);
1470         /* And now flush the block cache so that kernel sees the changes */
1471         invalidate_bdev(sb->s_bdev);
1472         mutex_lock(&inode->i_mutex);
1473         mutex_lock(&dqopt->dqonoff_mutex);
1474         if (sb_has_quota_enabled(sb, type)) {
1475                 error = -EBUSY;
1476                 goto out_lock;
1477         }
1478         /* We don't want quota and atime on quota files (deadlocks possible)
1479          * Also nobody should write to the file - we use special IO operations
1480          * which ignore the immutable bit. */
1481         down_write(&dqopt->dqptr_sem);
1482         oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1483         inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1484         up_write(&dqopt->dqptr_sem);
1485         sb->dq_op->drop(inode);
1486
1487         error = -EIO;
1488         dqopt->files[type] = igrab(inode);
1489         if (!dqopt->files[type])
1490                 goto out_lock;
1491         error = -EINVAL;
1492         if (!fmt->qf_ops->check_quota_file(sb, type))
1493                 goto out_file_init;
1494
1495         dqopt->ops[type] = fmt->qf_ops;
1496         dqopt->info[type].dqi_format = fmt;
1497         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1498         mutex_lock(&dqopt->dqio_mutex);
1499         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1500                 mutex_unlock(&dqopt->dqio_mutex);
1501                 goto out_file_init;
1502         }
1503         mutex_unlock(&dqopt->dqio_mutex);
1504         mutex_unlock(&inode->i_mutex);
1505         set_enable_flags(dqopt, type);
1506
1507         add_dquot_ref(sb, type);
1508         mutex_unlock(&dqopt->dqonoff_mutex);
1509
1510         return 0;
1511
1512 out_file_init:
1513         dqopt->files[type] = NULL;
1514         iput(inode);
1515 out_lock:
1516         mutex_unlock(&dqopt->dqonoff_mutex);
1517         if (oldflags != -1) {
1518                 down_write(&dqopt->dqptr_sem);
1519                 /* Set the flags back (in the case of accidental quotaon()
1520                  * on a wrong file we don't want to mess up the flags) */
1521                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1522                 inode->i_flags |= oldflags;
1523                 up_write(&dqopt->dqptr_sem);
1524         }
1525         mutex_unlock(&inode->i_mutex);
1526 out_fmt:
1527         put_quota_format(fmt);
1528
1529         return error; 
1530 }
1531
1532 /* Actual function called from quotactl() */
1533 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
1534 {
1535         struct nameidata nd;
1536         int error;
1537
1538         error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1539         if (error < 0)
1540                 return error;
1541         error = security_quota_on(nd.dentry);
1542         if (error)
1543                 goto out_path;
1544         /* Quota file not on the same filesystem? */
1545         if (nd.mnt->mnt_sb != sb)
1546                 error = -EXDEV;
1547         else
1548                 error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
1549 out_path:
1550         path_release(&nd);
1551         return error;
1552 }
1553
1554 /*
1555  * This function is used when filesystem needs to initialize quotas
1556  * during mount time.
1557  */
1558 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
1559                 int format_id, int type)
1560 {
1561         struct dentry *dentry;
1562         int error;
1563
1564         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
1565         if (IS_ERR(dentry))
1566                 return PTR_ERR(dentry);
1567
1568         if (!dentry->d_inode) {
1569                 error = -ENOENT;
1570                 goto out;
1571         }
1572
1573         error = security_quota_on(dentry);
1574         if (!error)
1575                 error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
1576
1577 out:
1578         dput(dentry);
1579         return error;
1580 }
1581
1582 /* Generic routine for getting common part of quota structure */
1583 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
1584 {
1585         struct mem_dqblk *dm = &dquot->dq_dqb;
1586
1587         spin_lock(&dq_data_lock);
1588         di->dqb_bhardlimit = dm->dqb_bhardlimit;
1589         di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
1590         di->dqb_curspace = dm->dqb_curspace;
1591         di->dqb_ihardlimit = dm->dqb_ihardlimit;
1592         di->dqb_isoftlimit = dm->dqb_isoftlimit;
1593         di->dqb_curinodes = dm->dqb_curinodes;
1594         di->dqb_btime = dm->dqb_btime;
1595         di->dqb_itime = dm->dqb_itime;
1596         di->dqb_valid = QIF_ALL;
1597         spin_unlock(&dq_data_lock);
1598 }
1599
1600 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1601 {
1602         struct dquot *dquot;
1603
1604         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1605         if (!(dquot = dqget(sb, id, type))) {
1606                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1607                 return -ESRCH;
1608         }
1609         do_get_dqblk(dquot, di);
1610         dqput(dquot);
1611         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1612         return 0;
1613 }
1614
1615 /* Generic routine for setting common part of quota structure */
1616 static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
1617 {
1618         struct mem_dqblk *dm = &dquot->dq_dqb;
1619         int check_blim = 0, check_ilim = 0;
1620
1621         spin_lock(&dq_data_lock);
1622         if (di->dqb_valid & QIF_SPACE) {
1623                 dm->dqb_curspace = di->dqb_curspace;
1624                 check_blim = 1;
1625         }
1626         if (di->dqb_valid & QIF_BLIMITS) {
1627                 dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
1628                 dm->dqb_bhardlimit = di->dqb_bhardlimit;
1629                 check_blim = 1;
1630         }
1631         if (di->dqb_valid & QIF_INODES) {
1632                 dm->dqb_curinodes = di->dqb_curinodes;
1633                 check_ilim = 1;
1634         }
1635         if (di->dqb_valid & QIF_ILIMITS) {
1636                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
1637                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
1638                 check_ilim = 1;
1639         }
1640         if (di->dqb_valid & QIF_BTIME)
1641                 dm->dqb_btime = di->dqb_btime;
1642         if (di->dqb_valid & QIF_ITIME)
1643                 dm->dqb_itime = di->dqb_itime;
1644
1645         if (check_blim) {
1646                 if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
1647                         dm->dqb_btime = 0;
1648                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1649                 }
1650                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
1651                         dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1652         }
1653         if (check_ilim) {
1654                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
1655                         dm->dqb_itime = 0;
1656                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1657                 }
1658                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
1659                         dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1660         }
1661         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
1662                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
1663         else
1664                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
1665         spin_unlock(&dq_data_lock);
1666         mark_dquot_dirty(dquot);
1667 }
1668
1669 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1670 {
1671         struct dquot *dquot;
1672
1673         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1674         if (!(dquot = dqget(sb, id, type))) {
1675                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1676                 return -ESRCH;
1677         }
1678         do_set_dqblk(dquot, di);
1679         dqput(dquot);
1680         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1681         return 0;
1682 }
1683
1684 /* Generic routine for getting common part of quota file information */
1685 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1686 {
1687         struct mem_dqinfo *mi;
1688   
1689         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1690         if (!sb_has_quota_enabled(sb, type)) {
1691                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1692                 return -ESRCH;
1693         }
1694         mi = sb_dqopt(sb)->info + type;
1695         spin_lock(&dq_data_lock);
1696         ii->dqi_bgrace = mi->dqi_bgrace;
1697         ii->dqi_igrace = mi->dqi_igrace;
1698         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
1699         ii->dqi_valid = IIF_ALL;
1700         spin_unlock(&dq_data_lock);
1701         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1702         return 0;
1703 }
1704
1705 /* Generic routine for setting common part of quota file information */
1706 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1707 {
1708         struct mem_dqinfo *mi;
1709
1710         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1711         if (!sb_has_quota_enabled(sb, type)) {
1712                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1713                 return -ESRCH;
1714         }
1715         mi = sb_dqopt(sb)->info + type;
1716         spin_lock(&dq_data_lock);
1717         if (ii->dqi_valid & IIF_BGRACE)
1718                 mi->dqi_bgrace = ii->dqi_bgrace;
1719         if (ii->dqi_valid & IIF_IGRACE)
1720                 mi->dqi_igrace = ii->dqi_igrace;
1721         if (ii->dqi_valid & IIF_FLAGS)
1722                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
1723         spin_unlock(&dq_data_lock);
1724         mark_info_dirty(sb, type);
1725         /* Force write to disk */
1726         sb->dq_op->write_info(sb, type);
1727         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1728         return 0;
1729 }
1730
1731 struct quotactl_ops vfs_quotactl_ops = {
1732         .quota_on       = vfs_quota_on,
1733         .quota_off      = vfs_quota_off,
1734         .quota_sync     = vfs_quota_sync,
1735         .get_info       = vfs_get_dqinfo,
1736         .set_info       = vfs_set_dqinfo,
1737         .get_dqblk      = vfs_get_dqblk,
1738         .set_dqblk      = vfs_set_dqblk
1739 };
1740
1741 static ctl_table fs_dqstats_table[] = {
1742         {
1743                 .ctl_name       = FS_DQ_LOOKUPS,
1744                 .procname       = "lookups",
1745                 .data           = &dqstats.lookups,
1746                 .maxlen         = sizeof(int),
1747                 .mode           = 0444,
1748                 .proc_handler   = &proc_dointvec,
1749         },
1750         {
1751                 .ctl_name       = FS_DQ_DROPS,
1752                 .procname       = "drops",
1753                 .data           = &dqstats.drops,
1754                 .maxlen         = sizeof(int),
1755                 .mode           = 0444,
1756                 .proc_handler   = &proc_dointvec,
1757         },
1758         {
1759                 .ctl_name       = FS_DQ_READS,
1760                 .procname       = "reads",
1761                 .data           = &dqstats.reads,
1762                 .maxlen         = sizeof(int),
1763                 .mode           = 0444,
1764                 .proc_handler   = &proc_dointvec,
1765         },
1766         {
1767                 .ctl_name       = FS_DQ_WRITES,
1768                 .procname       = "writes",
1769                 .data           = &dqstats.writes,
1770                 .maxlen         = sizeof(int),
1771                 .mode           = 0444,
1772                 .proc_handler   = &proc_dointvec,
1773         },
1774         {
1775                 .ctl_name       = FS_DQ_CACHE_HITS,
1776                 .procname       = "cache_hits",
1777                 .data           = &dqstats.cache_hits,
1778                 .maxlen         = sizeof(int),
1779                 .mode           = 0444,
1780                 .proc_handler   = &proc_dointvec,
1781         },
1782         {
1783                 .ctl_name       = FS_DQ_ALLOCATED,
1784                 .procname       = "allocated_dquots",
1785                 .data           = &dqstats.allocated_dquots,
1786                 .maxlen         = sizeof(int),
1787                 .mode           = 0444,
1788                 .proc_handler   = &proc_dointvec,
1789         },
1790         {
1791                 .ctl_name       = FS_DQ_FREE,
1792                 .procname       = "free_dquots",
1793                 .data           = &dqstats.free_dquots,
1794                 .maxlen         = sizeof(int),
1795                 .mode           = 0444,
1796                 .proc_handler   = &proc_dointvec,
1797         },
1798         {
1799                 .ctl_name       = FS_DQ_SYNCS,
1800                 .procname       = "syncs",
1801                 .data           = &dqstats.syncs,
1802                 .maxlen         = sizeof(int),
1803                 .mode           = 0444,
1804                 .proc_handler   = &proc_dointvec,
1805         },
1806         {
1807                 .ctl_name       = FS_DQ_WARNINGS,
1808                 .procname       = "warnings",
1809                 .data           = &flag_print_warnings,
1810                 .maxlen         = sizeof(int),
1811                 .mode           = 0644,
1812                 .proc_handler   = &proc_dointvec,
1813         },
1814         { .ctl_name = 0 },
1815 };
1816
1817 static ctl_table fs_table[] = {
1818         {
1819                 .ctl_name       = FS_DQSTATS,
1820                 .procname       = "quota",
1821                 .mode           = 0555,
1822                 .child          = fs_dqstats_table,
1823         },
1824         { .ctl_name = 0 },
1825 };
1826
1827 static ctl_table sys_table[] = {
1828         {
1829                 .ctl_name       = CTL_FS,
1830                 .procname       = "fs",
1831                 .mode           = 0555,
1832                 .child          = fs_table,
1833         },
1834         { .ctl_name = 0 },
1835 };
1836
1837 static int __init dquot_init(void)
1838 {
1839         int i;
1840         unsigned long nr_hash, order;
1841
1842         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
1843
1844         register_sysctl_table(sys_table);
1845
1846         dquot_cachep = kmem_cache_create("dquot", 
1847                         sizeof(struct dquot), sizeof(unsigned long) * 4,
1848                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1849                                 SLAB_MEM_SPREAD|SLAB_PANIC),
1850                         NULL, NULL);
1851
1852         order = 0;
1853         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
1854         if (!dquot_hash)
1855                 panic("Cannot create dquot hash table");
1856
1857         /* Find power-of-two hlist_heads which can fit into allocation */
1858         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
1859         dq_hash_bits = 0;
1860         do {
1861                 dq_hash_bits++;
1862         } while (nr_hash >> dq_hash_bits);
1863         dq_hash_bits--;
1864
1865         nr_hash = 1UL << dq_hash_bits;
1866         dq_hash_mask = nr_hash - 1;
1867         for (i = 0; i < nr_hash; i++)
1868                 INIT_HLIST_HEAD(dquot_hash + i);
1869
1870         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
1871                         nr_hash, order, (PAGE_SIZE << order));
1872
1873         set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
1874
1875         return 0;
1876 }
1877 module_init(dquot_init);
1878
1879 EXPORT_SYMBOL(register_quota_format);
1880 EXPORT_SYMBOL(unregister_quota_format);
1881 EXPORT_SYMBOL(dqstats);
1882 EXPORT_SYMBOL(dq_data_lock);
1883 EXPORT_SYMBOL(vfs_quota_on);
1884 EXPORT_SYMBOL(vfs_quota_on_mount);
1885 EXPORT_SYMBOL(vfs_quota_off);
1886 EXPORT_SYMBOL(vfs_quota_sync);
1887 EXPORT_SYMBOL(vfs_get_dqinfo);
1888 EXPORT_SYMBOL(vfs_set_dqinfo);
1889 EXPORT_SYMBOL(vfs_get_dqblk);
1890 EXPORT_SYMBOL(vfs_set_dqblk);
1891 EXPORT_SYMBOL(dquot_commit);
1892 EXPORT_SYMBOL(dquot_commit_info);
1893 EXPORT_SYMBOL(dquot_acquire);
1894 EXPORT_SYMBOL(dquot_release);
1895 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
1896 EXPORT_SYMBOL(dquot_initialize);
1897 EXPORT_SYMBOL(dquot_drop);
1898 EXPORT_SYMBOL(dquot_alloc_space);
1899 EXPORT_SYMBOL(dquot_alloc_inode);
1900 EXPORT_SYMBOL(dquot_free_space);
1901 EXPORT_SYMBOL(dquot_free_inode);
1902 EXPORT_SYMBOL(dquot_transfer);