Introduce path_put()
[linux-3.10.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/init.h>
73 #include <linux/module.h>
74 #include <linux/proc_fs.h>
75 #include <linux/security.h>
76 #include <linux/kmod.h>
77 #include <linux/namei.h>
78 #include <linux/buffer_head.h>
79 #include <linux/capability.h>
80 #include <linux/quotaops.h>
81 #include <linux/writeback.h> /* for inode_lock, oddly enough.. */
82 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
83 #include <net/netlink.h>
84 #include <net/genetlink.h>
85 #endif
86
87 #include <asm/uaccess.h>
88
89 #define __DQUOT_PARANOIA
90
91 /*
92  * There are two quota SMP locks. dq_list_lock protects all lists with quotas
93  * and quota formats and also dqstats structure containing statistics about the
94  * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
95  * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
96  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
97  * in inode_add_bytes() and inode_sub_bytes().
98  *
99  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
100  *
101  * Note that some things (eg. sb pointer, type, id) doesn't change during
102  * the life of the dquot structure and so needn't to be protected by a lock
103  *
104  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
105  * operation is just reading pointers from inode (or not using them at all) the
106  * read lock is enough. If pointers are altered function must hold write lock
107  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
108  * for altering the flag i_mutex is also needed).  If operation is holding
109  * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
110  * dqonoff_mutex.
111  * This locking assures that:
112  *   a) update/access to dquot pointers in inode is serialized
113  *   b) everyone is guarded against invalidate_dquots()
114  *
115  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
116  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
117  * Currently dquot is locked only when it is being read to memory (or space for
118  * it is being allocated) on the first dqget() and when it is being released on
119  * the last dqput(). The allocation and release oparations are serialized by
120  * the dq_lock and by checking the use count in dquot_release().  Write
121  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
122  * spinlock to internal buffers before writing.
123  *
124  * Lock ordering (including related VFS locks) is the following:
125  *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
126  *   dqio_mutex
127  * i_mutex on quota files is special (it's below dqio_mutex)
128  */
129
130 static DEFINE_SPINLOCK(dq_list_lock);
131 DEFINE_SPINLOCK(dq_data_lock);
132
133 static char *quotatypes[] = INITQFNAMES;
134 static struct quota_format_type *quota_formats; /* List of registered formats */
135 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
136
137 /* SLAB cache for dquot structures */
138 static struct kmem_cache *dquot_cachep;
139
140 int register_quota_format(struct quota_format_type *fmt)
141 {
142         spin_lock(&dq_list_lock);
143         fmt->qf_next = quota_formats;
144         quota_formats = fmt;
145         spin_unlock(&dq_list_lock);
146         return 0;
147 }
148
149 void unregister_quota_format(struct quota_format_type *fmt)
150 {
151         struct quota_format_type **actqf;
152
153         spin_lock(&dq_list_lock);
154         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
155         if (*actqf)
156                 *actqf = (*actqf)->qf_next;
157         spin_unlock(&dq_list_lock);
158 }
159
160 static struct quota_format_type *find_quota_format(int id)
161 {
162         struct quota_format_type *actqf;
163
164         spin_lock(&dq_list_lock);
165         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
166         if (!actqf || !try_module_get(actqf->qf_owner)) {
167                 int qm;
168
169                 spin_unlock(&dq_list_lock);
170                 
171                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
172                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
173                         return NULL;
174
175                 spin_lock(&dq_list_lock);
176                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
177                 if (actqf && !try_module_get(actqf->qf_owner))
178                         actqf = NULL;
179         }
180         spin_unlock(&dq_list_lock);
181         return actqf;
182 }
183
184 static void put_quota_format(struct quota_format_type *fmt)
185 {
186         module_put(fmt->qf_owner);
187 }
188
189 /*
190  * Dquot List Management:
191  * The quota code uses three lists for dquot management: the inuse_list,
192  * free_dquots, and dquot_hash[] array. A single dquot structure may be
193  * on all three lists, depending on its current state.
194  *
195  * All dquots are placed to the end of inuse_list when first created, and this
196  * list is used for invalidate operation, which must look at every dquot.
197  *
198  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
199  * and this list is searched whenever we need an available dquot.  Dquots are
200  * removed from the list as soon as they are used again, and
201  * dqstats.free_dquots gives the number of dquots on the list. When
202  * dquot is invalidated it's completely released from memory.
203  *
204  * Dquots with a specific identity (device, type and id) are placed on
205  * one of the dquot_hash[] hash chains. The provides an efficient search
206  * mechanism to locate a specific dquot.
207  */
208
209 static LIST_HEAD(inuse_list);
210 static LIST_HEAD(free_dquots);
211 static unsigned int dq_hash_bits, dq_hash_mask;
212 static struct hlist_head *dquot_hash;
213
214 struct dqstats dqstats;
215
216 static void dqput(struct dquot *dquot);
217
218 static inline unsigned int
219 hashfn(const struct super_block *sb, unsigned int id, int type)
220 {
221         unsigned long tmp;
222
223         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
224         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
225 }
226
227 /*
228  * Following list functions expect dq_list_lock to be held
229  */
230 static inline void insert_dquot_hash(struct dquot *dquot)
231 {
232         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
233         hlist_add_head(&dquot->dq_hash, head);
234 }
235
236 static inline void remove_dquot_hash(struct dquot *dquot)
237 {
238         hlist_del_init(&dquot->dq_hash);
239 }
240
241 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
242 {
243         struct hlist_node *node;
244         struct dquot *dquot;
245
246         hlist_for_each (node, dquot_hash+hashent) {
247                 dquot = hlist_entry(node, struct dquot, dq_hash);
248                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
249                         return dquot;
250         }
251         return NODQUOT;
252 }
253
254 /* Add a dquot to the tail of the free list */
255 static inline void put_dquot_last(struct dquot *dquot)
256 {
257         list_add_tail(&dquot->dq_free, &free_dquots);
258         dqstats.free_dquots++;
259 }
260
261 static inline void remove_free_dquot(struct dquot *dquot)
262 {
263         if (list_empty(&dquot->dq_free))
264                 return;
265         list_del_init(&dquot->dq_free);
266         dqstats.free_dquots--;
267 }
268
269 static inline void put_inuse(struct dquot *dquot)
270 {
271         /* We add to the back of inuse list so we don't have to restart
272          * when traversing this list and we block */
273         list_add_tail(&dquot->dq_inuse, &inuse_list);
274         dqstats.allocated_dquots++;
275 }
276
277 static inline void remove_inuse(struct dquot *dquot)
278 {
279         dqstats.allocated_dquots--;
280         list_del(&dquot->dq_inuse);
281 }
282 /*
283  * End of list functions needing dq_list_lock
284  */
285
286 static void wait_on_dquot(struct dquot *dquot)
287 {
288         mutex_lock(&dquot->dq_lock);
289         mutex_unlock(&dquot->dq_lock);
290 }
291
292 #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
293
294 int dquot_mark_dquot_dirty(struct dquot *dquot)
295 {
296         spin_lock(&dq_list_lock);
297         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
298                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
299                                 info[dquot->dq_type].dqi_dirty_list);
300         spin_unlock(&dq_list_lock);
301         return 0;
302 }
303
304 /* This function needs dq_list_lock */
305 static inline int clear_dquot_dirty(struct dquot *dquot)
306 {
307         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
308                 return 0;
309         list_del_init(&dquot->dq_dirty);
310         return 1;
311 }
312
313 void mark_info_dirty(struct super_block *sb, int type)
314 {
315         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
316 }
317 EXPORT_SYMBOL(mark_info_dirty);
318
319 /*
320  *      Read dquot from disk and alloc space for it
321  */
322
323 int dquot_acquire(struct dquot *dquot)
324 {
325         int ret = 0, ret2 = 0;
326         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
327
328         mutex_lock(&dquot->dq_lock);
329         mutex_lock(&dqopt->dqio_mutex);
330         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
331                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
332         if (ret < 0)
333                 goto out_iolock;
334         set_bit(DQ_READ_B, &dquot->dq_flags);
335         /* Instantiate dquot if needed */
336         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
337                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
338                 /* Write the info if needed */
339                 if (info_dirty(&dqopt->info[dquot->dq_type]))
340                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
341                 if (ret < 0)
342                         goto out_iolock;
343                 if (ret2 < 0) {
344                         ret = ret2;
345                         goto out_iolock;
346                 }
347         }
348         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
349 out_iolock:
350         mutex_unlock(&dqopt->dqio_mutex);
351         mutex_unlock(&dquot->dq_lock);
352         return ret;
353 }
354
355 /*
356  *      Write dquot to disk
357  */
358 int dquot_commit(struct dquot *dquot)
359 {
360         int ret = 0, ret2 = 0;
361         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
362
363         mutex_lock(&dqopt->dqio_mutex);
364         spin_lock(&dq_list_lock);
365         if (!clear_dquot_dirty(dquot)) {
366                 spin_unlock(&dq_list_lock);
367                 goto out_sem;
368         }
369         spin_unlock(&dq_list_lock);
370         /* Inactive dquot can be only if there was error during read/init
371          * => we have better not writing it */
372         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
373                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
374                 if (info_dirty(&dqopt->info[dquot->dq_type]))
375                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
376                 if (ret >= 0)
377                         ret = ret2;
378         }
379 out_sem:
380         mutex_unlock(&dqopt->dqio_mutex);
381         return ret;
382 }
383
384 /*
385  *      Release dquot
386  */
387 int dquot_release(struct dquot *dquot)
388 {
389         int ret = 0, ret2 = 0;
390         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
391
392         mutex_lock(&dquot->dq_lock);
393         /* Check whether we are not racing with some other dqget() */
394         if (atomic_read(&dquot->dq_count) > 1)
395                 goto out_dqlock;
396         mutex_lock(&dqopt->dqio_mutex);
397         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
398                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
399                 /* Write the info */
400                 if (info_dirty(&dqopt->info[dquot->dq_type]))
401                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
402                 if (ret >= 0)
403                         ret = ret2;
404         }
405         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
406         mutex_unlock(&dqopt->dqio_mutex);
407 out_dqlock:
408         mutex_unlock(&dquot->dq_lock);
409         return ret;
410 }
411
412 /* Invalidate all dquots on the list. Note that this function is called after
413  * quota is disabled and pointers from inodes removed so there cannot be new
414  * quota users. There can still be some users of quotas due to inodes being
415  * just deleted or pruned by prune_icache() (those are not attached to any
416  * list). We have to wait for such users.
417  */
418 static void invalidate_dquots(struct super_block *sb, int type)
419 {
420         struct dquot *dquot, *tmp;
421
422 restart:
423         spin_lock(&dq_list_lock);
424         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
425                 if (dquot->dq_sb != sb)
426                         continue;
427                 if (dquot->dq_type != type)
428                         continue;
429                 /* Wait for dquot users */
430                 if (atomic_read(&dquot->dq_count)) {
431                         DEFINE_WAIT(wait);
432
433                         atomic_inc(&dquot->dq_count);
434                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
435                                         TASK_UNINTERRUPTIBLE);
436                         spin_unlock(&dq_list_lock);
437                         /* Once dqput() wakes us up, we know it's time to free
438                          * the dquot.
439                          * IMPORTANT: we rely on the fact that there is always
440                          * at most one process waiting for dquot to free.
441                          * Otherwise dq_count would be > 1 and we would never
442                          * wake up.
443                          */
444                         if (atomic_read(&dquot->dq_count) > 1)
445                                 schedule();
446                         finish_wait(&dquot->dq_wait_unused, &wait);
447                         dqput(dquot);
448                         /* At this moment dquot() need not exist (it could be
449                          * reclaimed by prune_dqcache(). Hence we must
450                          * restart. */
451                         goto restart;
452                 }
453                 /*
454                  * Quota now has no users and it has been written on last
455                  * dqput()
456                  */
457                 remove_dquot_hash(dquot);
458                 remove_free_dquot(dquot);
459                 remove_inuse(dquot);
460                 kmem_cache_free(dquot_cachep, dquot);
461         }
462         spin_unlock(&dq_list_lock);
463 }
464
465 int vfs_quota_sync(struct super_block *sb, int type)
466 {
467         struct list_head *dirty;
468         struct dquot *dquot;
469         struct quota_info *dqopt = sb_dqopt(sb);
470         int cnt;
471
472         mutex_lock(&dqopt->dqonoff_mutex);
473         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
474                 if (type != -1 && cnt != type)
475                         continue;
476                 if (!sb_has_quota_enabled(sb, cnt))
477                         continue;
478                 spin_lock(&dq_list_lock);
479                 dirty = &dqopt->info[cnt].dqi_dirty_list;
480                 while (!list_empty(dirty)) {
481                         dquot = list_first_entry(dirty, struct dquot, dq_dirty);
482                         /* Dirty and inactive can be only bad dquot... */
483                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
484                                 clear_dquot_dirty(dquot);
485                                 continue;
486                         }
487                         /* Now we have active dquot from which someone is
488                          * holding reference so we can safely just increase
489                          * use count */
490                         atomic_inc(&dquot->dq_count);
491                         dqstats.lookups++;
492                         spin_unlock(&dq_list_lock);
493                         sb->dq_op->write_dquot(dquot);
494                         dqput(dquot);
495                         spin_lock(&dq_list_lock);
496                 }
497                 spin_unlock(&dq_list_lock);
498         }
499
500         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
501                 if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
502                         && info_dirty(&dqopt->info[cnt]))
503                         sb->dq_op->write_info(sb, cnt);
504         spin_lock(&dq_list_lock);
505         dqstats.syncs++;
506         spin_unlock(&dq_list_lock);
507         mutex_unlock(&dqopt->dqonoff_mutex);
508
509         return 0;
510 }
511
512 /* Free unused dquots from cache */
513 static void prune_dqcache(int count)
514 {
515         struct list_head *head;
516         struct dquot *dquot;
517
518         head = free_dquots.prev;
519         while (head != &free_dquots && count) {
520                 dquot = list_entry(head, struct dquot, dq_free);
521                 remove_dquot_hash(dquot);
522                 remove_free_dquot(dquot);
523                 remove_inuse(dquot);
524                 kmem_cache_free(dquot_cachep, dquot);
525                 count--;
526                 head = free_dquots.prev;
527         }
528 }
529
530 /*
531  * This is called from kswapd when we think we need some
532  * more memory
533  */
534
535 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
536 {
537         if (nr) {
538                 spin_lock(&dq_list_lock);
539                 prune_dqcache(nr);
540                 spin_unlock(&dq_list_lock);
541         }
542         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
543 }
544
545 static struct shrinker dqcache_shrinker = {
546         .shrink = shrink_dqcache_memory,
547         .seeks = DEFAULT_SEEKS,
548 };
549
550 /*
551  * Put reference to dquot
552  * NOTE: If you change this function please check whether dqput_blocks() works right...
553  * MUST be called with either dqptr_sem or dqonoff_mutex held
554  */
555 static void dqput(struct dquot *dquot)
556 {
557         if (!dquot)
558                 return;
559 #ifdef __DQUOT_PARANOIA
560         if (!atomic_read(&dquot->dq_count)) {
561                 printk("VFS: dqput: trying to free free dquot\n");
562                 printk("VFS: device %s, dquot of %s %d\n",
563                         dquot->dq_sb->s_id,
564                         quotatypes[dquot->dq_type],
565                         dquot->dq_id);
566                 BUG();
567         }
568 #endif
569         
570         spin_lock(&dq_list_lock);
571         dqstats.drops++;
572         spin_unlock(&dq_list_lock);
573 we_slept:
574         spin_lock(&dq_list_lock);
575         if (atomic_read(&dquot->dq_count) > 1) {
576                 /* We have more than one user... nothing to do */
577                 atomic_dec(&dquot->dq_count);
578                 /* Releasing dquot during quotaoff phase? */
579                 if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
580                     atomic_read(&dquot->dq_count) == 1)
581                         wake_up(&dquot->dq_wait_unused);
582                 spin_unlock(&dq_list_lock);
583                 return;
584         }
585         /* Need to release dquot? */
586         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
587                 spin_unlock(&dq_list_lock);
588                 /* Commit dquot before releasing */
589                 dquot->dq_sb->dq_op->write_dquot(dquot);
590                 goto we_slept;
591         }
592         /* Clear flag in case dquot was inactive (something bad happened) */
593         clear_dquot_dirty(dquot);
594         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
595                 spin_unlock(&dq_list_lock);
596                 dquot->dq_sb->dq_op->release_dquot(dquot);
597                 goto we_slept;
598         }
599         atomic_dec(&dquot->dq_count);
600 #ifdef __DQUOT_PARANOIA
601         /* sanity check */
602         BUG_ON(!list_empty(&dquot->dq_free));
603 #endif
604         put_dquot_last(dquot);
605         spin_unlock(&dq_list_lock);
606 }
607
608 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
609 {
610         struct dquot *dquot;
611
612         dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
613         if(!dquot)
614                 return NODQUOT;
615
616         mutex_init(&dquot->dq_lock);
617         INIT_LIST_HEAD(&dquot->dq_free);
618         INIT_LIST_HEAD(&dquot->dq_inuse);
619         INIT_HLIST_NODE(&dquot->dq_hash);
620         INIT_LIST_HEAD(&dquot->dq_dirty);
621         init_waitqueue_head(&dquot->dq_wait_unused);
622         dquot->dq_sb = sb;
623         dquot->dq_type = type;
624         atomic_set(&dquot->dq_count, 1);
625
626         return dquot;
627 }
628
629 /*
630  * Get reference to dquot
631  * MUST be called with either dqptr_sem or dqonoff_mutex held
632  */
633 static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
634 {
635         unsigned int hashent = hashfn(sb, id, type);
636         struct dquot *dquot, *empty = NODQUOT;
637
638         if (!sb_has_quota_enabled(sb, type))
639                 return NODQUOT;
640 we_slept:
641         spin_lock(&dq_list_lock);
642         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
643                 if (empty == NODQUOT) {
644                         spin_unlock(&dq_list_lock);
645                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
646                                 schedule();     /* Try to wait for a moment... */
647                         goto we_slept;
648                 }
649                 dquot = empty;
650                 dquot->dq_id = id;
651                 /* all dquots go on the inuse_list */
652                 put_inuse(dquot);
653                 /* hash it first so it can be found */
654                 insert_dquot_hash(dquot);
655                 dqstats.lookups++;
656                 spin_unlock(&dq_list_lock);
657         } else {
658                 if (!atomic_read(&dquot->dq_count))
659                         remove_free_dquot(dquot);
660                 atomic_inc(&dquot->dq_count);
661                 dqstats.cache_hits++;
662                 dqstats.lookups++;
663                 spin_unlock(&dq_list_lock);
664                 if (empty)
665                         kmem_cache_free(dquot_cachep, empty);
666         }
667         /* Wait for dq_lock - after this we know that either dquot_release() is already
668          * finished or it will be canceled due to dq_count > 1 test */
669         wait_on_dquot(dquot);
670         /* Read the dquot and instantiate it (everything done only if needed) */
671         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
672                 dqput(dquot);
673                 return NODQUOT;
674         }
675 #ifdef __DQUOT_PARANOIA
676         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
677 #endif
678
679         return dquot;
680 }
681
682 static int dqinit_needed(struct inode *inode, int type)
683 {
684         int cnt;
685
686         if (IS_NOQUOTA(inode))
687                 return 0;
688         if (type != -1)
689                 return inode->i_dquot[type] == NODQUOT;
690         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
691                 if (inode->i_dquot[cnt] == NODQUOT)
692                         return 1;
693         return 0;
694 }
695
696 /* This routine is guarded by dqonoff_mutex mutex */
697 static void add_dquot_ref(struct super_block *sb, int type)
698 {
699         struct inode *inode, *old_inode = NULL;
700
701         spin_lock(&inode_lock);
702         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
703                 if (!atomic_read(&inode->i_writecount))
704                         continue;
705                 if (!dqinit_needed(inode, type))
706                         continue;
707                 if (inode->i_state & (I_FREEING|I_WILL_FREE))
708                         continue;
709
710                 __iget(inode);
711                 spin_unlock(&inode_lock);
712
713                 iput(old_inode);
714                 sb->dq_op->initialize(inode, type);
715                 /* We hold a reference to 'inode' so it couldn't have been
716                  * removed from s_inodes list while we dropped the inode_lock.
717                  * We cannot iput the inode now as we can be holding the last
718                  * reference and we cannot iput it under inode_lock. So we
719                  * keep the reference and iput it later. */
720                 old_inode = inode;
721                 spin_lock(&inode_lock);
722         }
723         spin_unlock(&inode_lock);
724         iput(old_inode);
725 }
726
727 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
728 static inline int dqput_blocks(struct dquot *dquot)
729 {
730         if (atomic_read(&dquot->dq_count) <= 1)
731                 return 1;
732         return 0;
733 }
734
735 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
736 /* We can't race with anybody because we hold dqptr_sem for writing... */
737 static int remove_inode_dquot_ref(struct inode *inode, int type,
738                                   struct list_head *tofree_head)
739 {
740         struct dquot *dquot = inode->i_dquot[type];
741
742         inode->i_dquot[type] = NODQUOT;
743         if (dquot != NODQUOT) {
744                 if (dqput_blocks(dquot)) {
745 #ifdef __DQUOT_PARANOIA
746                         if (atomic_read(&dquot->dq_count) != 1)
747                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
748 #endif
749                         spin_lock(&dq_list_lock);
750                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
751                         spin_unlock(&dq_list_lock);
752                         return 1;
753                 }
754                 else
755                         dqput(dquot);   /* We have guaranteed we won't block */
756         }
757         return 0;
758 }
759
760 /* Free list of dquots - called from inode.c */
761 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
762 static void put_dquot_list(struct list_head *tofree_head)
763 {
764         struct list_head *act_head;
765         struct dquot *dquot;
766
767         act_head = tofree_head->next;
768         /* So now we have dquots on the list... Just free them */
769         while (act_head != tofree_head) {
770                 dquot = list_entry(act_head, struct dquot, dq_free);
771                 act_head = act_head->next;
772                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
773                 dqput(dquot);
774         }
775 }
776
777 static void remove_dquot_ref(struct super_block *sb, int type,
778                 struct list_head *tofree_head)
779 {
780         struct inode *inode;
781
782         spin_lock(&inode_lock);
783         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
784                 if (!IS_NOQUOTA(inode))
785                         remove_inode_dquot_ref(inode, type, tofree_head);
786         }
787         spin_unlock(&inode_lock);
788 }
789
790 /* Gather all references from inodes and drop them */
791 static void drop_dquot_ref(struct super_block *sb, int type)
792 {
793         LIST_HEAD(tofree_head);
794
795         if (sb->dq_op) {
796                 down_write(&sb_dqopt(sb)->dqptr_sem);
797                 remove_dquot_ref(sb, type, &tofree_head);
798                 up_write(&sb_dqopt(sb)->dqptr_sem);
799                 put_dquot_list(&tofree_head);
800         }
801 }
802
803 static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
804 {
805         dquot->dq_dqb.dqb_curinodes += number;
806 }
807
808 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
809 {
810         dquot->dq_dqb.dqb_curspace += number;
811 }
812
813 static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
814 {
815         if (dquot->dq_dqb.dqb_curinodes > number)
816                 dquot->dq_dqb.dqb_curinodes -= number;
817         else
818                 dquot->dq_dqb.dqb_curinodes = 0;
819         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
820                 dquot->dq_dqb.dqb_itime = (time_t) 0;
821         clear_bit(DQ_INODES_B, &dquot->dq_flags);
822 }
823
824 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
825 {
826         if (dquot->dq_dqb.dqb_curspace > number)
827                 dquot->dq_dqb.dqb_curspace -= number;
828         else
829                 dquot->dq_dqb.dqb_curspace = 0;
830         if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
831                 dquot->dq_dqb.dqb_btime = (time_t) 0;
832         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
833 }
834
835 static int warning_issued(struct dquot *dquot, const int warntype)
836 {
837         int flag = (warntype == QUOTA_NL_BHARDWARN ||
838                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
839                 ((warntype == QUOTA_NL_IHARDWARN ||
840                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
841
842         if (!flag)
843                 return 0;
844         return test_and_set_bit(flag, &dquot->dq_flags);
845 }
846
847 #ifdef CONFIG_PRINT_QUOTA_WARNING
848 static int flag_print_warnings = 1;
849
850 static inline int need_print_warning(struct dquot *dquot)
851 {
852         if (!flag_print_warnings)
853                 return 0;
854
855         switch (dquot->dq_type) {
856                 case USRQUOTA:
857                         return current->fsuid == dquot->dq_id;
858                 case GRPQUOTA:
859                         return in_group_p(dquot->dq_id);
860         }
861         return 0;
862 }
863
864 /* Print warning to user which exceeded quota */
865 static void print_warning(struct dquot *dquot, const int warntype)
866 {
867         char *msg = NULL;
868         struct tty_struct *tty;
869
870         if (!need_print_warning(dquot))
871                 return;
872
873         mutex_lock(&tty_mutex);
874         tty = get_current_tty();
875         if (!tty)
876                 goto out_lock;
877         tty_write_message(tty, dquot->dq_sb->s_id);
878         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
879                 tty_write_message(tty, ": warning, ");
880         else
881                 tty_write_message(tty, ": write failed, ");
882         tty_write_message(tty, quotatypes[dquot->dq_type]);
883         switch (warntype) {
884                 case QUOTA_NL_IHARDWARN:
885                         msg = " file limit reached.\r\n";
886                         break;
887                 case QUOTA_NL_ISOFTLONGWARN:
888                         msg = " file quota exceeded too long.\r\n";
889                         break;
890                 case QUOTA_NL_ISOFTWARN:
891                         msg = " file quota exceeded.\r\n";
892                         break;
893                 case QUOTA_NL_BHARDWARN:
894                         msg = " block limit reached.\r\n";
895                         break;
896                 case QUOTA_NL_BSOFTLONGWARN:
897                         msg = " block quota exceeded too long.\r\n";
898                         break;
899                 case QUOTA_NL_BSOFTWARN:
900                         msg = " block quota exceeded.\r\n";
901                         break;
902         }
903         tty_write_message(tty, msg);
904 out_lock:
905         mutex_unlock(&tty_mutex);
906 }
907 #endif
908
909 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
910
911 /* Netlink family structure for quota */
912 static struct genl_family quota_genl_family = {
913         .id = GENL_ID_GENERATE,
914         .hdrsize = 0,
915         .name = "VFS_DQUOT",
916         .version = 1,
917         .maxattr = QUOTA_NL_A_MAX,
918 };
919
920 /* Send warning to userspace about user which exceeded quota */
921 static void send_warning(const struct dquot *dquot, const char warntype)
922 {
923         static atomic_t seq;
924         struct sk_buff *skb;
925         void *msg_head;
926         int ret;
927         int msg_size = 4 * nla_total_size(sizeof(u32)) +
928                        2 * nla_total_size(sizeof(u64));
929
930         /* We have to allocate using GFP_NOFS as we are called from a
931          * filesystem performing write and thus further recursion into
932          * the fs to free some data could cause deadlocks. */
933         skb = genlmsg_new(msg_size, GFP_NOFS);
934         if (!skb) {
935                 printk(KERN_ERR
936                   "VFS: Not enough memory to send quota warning.\n");
937                 return;
938         }
939         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
940                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
941         if (!msg_head) {
942                 printk(KERN_ERR
943                   "VFS: Cannot store netlink header in quota warning.\n");
944                 goto err_out;
945         }
946         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, dquot->dq_type);
947         if (ret)
948                 goto attr_err_out;
949         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_id);
950         if (ret)
951                 goto attr_err_out;
952         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
953         if (ret)
954                 goto attr_err_out;
955         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR,
956                 MAJOR(dquot->dq_sb->s_dev));
957         if (ret)
958                 goto attr_err_out;
959         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,
960                 MINOR(dquot->dq_sb->s_dev));
961         if (ret)
962                 goto attr_err_out;
963         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current->user->uid);
964         if (ret)
965                 goto attr_err_out;
966         genlmsg_end(skb, msg_head);
967
968         ret = genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
969         if (ret < 0 && ret != -ESRCH)
970                 printk(KERN_ERR
971                         "VFS: Failed to send notification message: %d\n", ret);
972         return;
973 attr_err_out:
974         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
975 err_out:
976         kfree_skb(skb);
977 }
978 #endif
979
980 static inline void flush_warnings(struct dquot * const *dquots, char *warntype)
981 {
982         int i;
983
984         for (i = 0; i < MAXQUOTAS; i++)
985                 if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN &&
986                     !warning_issued(dquots[i], warntype[i])) {
987 #ifdef CONFIG_PRINT_QUOTA_WARNING
988                         print_warning(dquots[i], warntype[i]);
989 #endif
990 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
991                         send_warning(dquots[i], warntype[i]);
992 #endif
993                 }
994 }
995
996 static inline char ignore_hardlimit(struct dquot *dquot)
997 {
998         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
999
1000         return capable(CAP_SYS_RESOURCE) &&
1001             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
1002 }
1003
1004 /* needs dq_data_lock */
1005 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
1006 {
1007         *warntype = QUOTA_NL_NOWARN;
1008         if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
1009                 return QUOTA_OK;
1010
1011         if (dquot->dq_dqb.dqb_ihardlimit &&
1012            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
1013             !ignore_hardlimit(dquot)) {
1014                 *warntype = QUOTA_NL_IHARDWARN;
1015                 return NO_QUOTA;
1016         }
1017
1018         if (dquot->dq_dqb.dqb_isoftlimit &&
1019            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1020             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
1021             !ignore_hardlimit(dquot)) {
1022                 *warntype = QUOTA_NL_ISOFTLONGWARN;
1023                 return NO_QUOTA;
1024         }
1025
1026         if (dquot->dq_dqb.dqb_isoftlimit &&
1027            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1028             dquot->dq_dqb.dqb_itime == 0) {
1029                 *warntype = QUOTA_NL_ISOFTWARN;
1030                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1031         }
1032
1033         return QUOTA_OK;
1034 }
1035
1036 /* needs dq_data_lock */
1037 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
1038 {
1039         *warntype = QUOTA_NL_NOWARN;
1040         if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
1041                 return QUOTA_OK;
1042
1043         if (dquot->dq_dqb.dqb_bhardlimit &&
1044            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
1045             !ignore_hardlimit(dquot)) {
1046                 if (!prealloc)
1047                         *warntype = QUOTA_NL_BHARDWARN;
1048                 return NO_QUOTA;
1049         }
1050
1051         if (dquot->dq_dqb.dqb_bsoftlimit &&
1052            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
1053             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
1054             !ignore_hardlimit(dquot)) {
1055                 if (!prealloc)
1056                         *warntype = QUOTA_NL_BSOFTLONGWARN;
1057                 return NO_QUOTA;
1058         }
1059
1060         if (dquot->dq_dqb.dqb_bsoftlimit &&
1061            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
1062             dquot->dq_dqb.dqb_btime == 0) {
1063                 if (!prealloc) {
1064                         *warntype = QUOTA_NL_BSOFTWARN;
1065                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1066                 }
1067                 else
1068                         /*
1069                          * We don't allow preallocation to exceed softlimit so exceeding will
1070                          * be always printed
1071                          */
1072                         return NO_QUOTA;
1073         }
1074
1075         return QUOTA_OK;
1076 }
1077
1078 /*
1079  *      Initialize quota pointers in inode
1080  *      Transaction must be started at entry
1081  */
1082 int dquot_initialize(struct inode *inode, int type)
1083 {
1084         unsigned int id = 0;
1085         int cnt, ret = 0;
1086
1087         /* First test before acquiring mutex - solves deadlocks when we
1088          * re-enter the quota code and are already holding the mutex */
1089         if (IS_NOQUOTA(inode))
1090                 return 0;
1091         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1092         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
1093         if (IS_NOQUOTA(inode))
1094                 goto out_err;
1095         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1096                 if (type != -1 && cnt != type)
1097                         continue;
1098                 if (inode->i_dquot[cnt] == NODQUOT) {
1099                         switch (cnt) {
1100                                 case USRQUOTA:
1101                                         id = inode->i_uid;
1102                                         break;
1103                                 case GRPQUOTA:
1104                                         id = inode->i_gid;
1105                                         break;
1106                         }
1107                         inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
1108                 }
1109         }
1110 out_err:
1111         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1112         return ret;
1113 }
1114
1115 /*
1116  *      Release all quotas referenced by inode
1117  *      Transaction must be started at an entry
1118  */
1119 int dquot_drop(struct inode *inode)
1120 {
1121         int cnt;
1122
1123         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1124         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1125                 if (inode->i_dquot[cnt] != NODQUOT) {
1126                         dqput(inode->i_dquot[cnt]);
1127                         inode->i_dquot[cnt] = NODQUOT;
1128                 }
1129         }
1130         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1131         return 0;
1132 }
1133
1134 /*
1135  * Following four functions update i_blocks+i_bytes fields and
1136  * quota information (together with appropriate checks)
1137  * NOTE: We absolutely rely on the fact that caller dirties
1138  * the inode (usually macros in quotaops.h care about this) and
1139  * holds a handle for the current transaction so that dquot write and
1140  * inode write go into the same transaction.
1141  */
1142
1143 /*
1144  * This operation can block, but only after everything is updated
1145  */
1146 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1147 {
1148         int cnt, ret = NO_QUOTA;
1149         char warntype[MAXQUOTAS];
1150
1151         /* First test before acquiring mutex - solves deadlocks when we
1152          * re-enter the quota code and are already holding the mutex */
1153         if (IS_NOQUOTA(inode)) {
1154 out_add:
1155                 inode_add_bytes(inode, number);
1156                 return QUOTA_OK;
1157         }
1158         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1159                 warntype[cnt] = QUOTA_NL_NOWARN;
1160
1161         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1162         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1163                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1164                 goto out_add;
1165         }
1166         spin_lock(&dq_data_lock);
1167         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1168                 if (inode->i_dquot[cnt] == NODQUOT)
1169                         continue;
1170                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1171                         goto warn_put_all;
1172         }
1173         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1174                 if (inode->i_dquot[cnt] == NODQUOT)
1175                         continue;
1176                 dquot_incr_space(inode->i_dquot[cnt], number);
1177         }
1178         inode_add_bytes(inode, number);
1179         ret = QUOTA_OK;
1180 warn_put_all:
1181         spin_unlock(&dq_data_lock);
1182         if (ret == QUOTA_OK)
1183                 /* Dirtify all the dquots - this can block when journalling */
1184                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1185                         if (inode->i_dquot[cnt])
1186                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1187         flush_warnings(inode->i_dquot, warntype);
1188         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1189         return ret;
1190 }
1191
1192 /*
1193  * This operation can block, but only after everything is updated
1194  */
1195 int dquot_alloc_inode(const struct inode *inode, unsigned long number)
1196 {
1197         int cnt, ret = NO_QUOTA;
1198         char warntype[MAXQUOTAS];
1199
1200         /* First test before acquiring mutex - solves deadlocks when we
1201          * re-enter the quota code and are already holding the mutex */
1202         if (IS_NOQUOTA(inode))
1203                 return QUOTA_OK;
1204         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1205                 warntype[cnt] = QUOTA_NL_NOWARN;
1206         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1207         if (IS_NOQUOTA(inode)) {
1208                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1209                 return QUOTA_OK;
1210         }
1211         spin_lock(&dq_data_lock);
1212         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1213                 if (inode->i_dquot[cnt] == NODQUOT)
1214                         continue;
1215                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1216                         goto warn_put_all;
1217         }
1218
1219         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1220                 if (inode->i_dquot[cnt] == NODQUOT)
1221                         continue;
1222                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1223         }
1224         ret = QUOTA_OK;
1225 warn_put_all:
1226         spin_unlock(&dq_data_lock);
1227         if (ret == QUOTA_OK)
1228                 /* Dirtify all the dquots - this can block when journalling */
1229                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1230                         if (inode->i_dquot[cnt])
1231                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1232         flush_warnings(inode->i_dquot, warntype);
1233         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1234         return ret;
1235 }
1236
1237 /*
1238  * This operation can block, but only after everything is updated
1239  */
1240 int dquot_free_space(struct inode *inode, qsize_t number)
1241 {
1242         unsigned int cnt;
1243
1244         /* First test before acquiring mutex - solves deadlocks when we
1245          * re-enter the quota code and are already holding the mutex */
1246         if (IS_NOQUOTA(inode)) {
1247 out_sub:
1248                 inode_sub_bytes(inode, number);
1249                 return QUOTA_OK;
1250         }
1251         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1252         /* Now recheck reliably when holding dqptr_sem */
1253         if (IS_NOQUOTA(inode)) {
1254                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1255                 goto out_sub;
1256         }
1257         spin_lock(&dq_data_lock);
1258         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1259                 if (inode->i_dquot[cnt] == NODQUOT)
1260                         continue;
1261                 dquot_decr_space(inode->i_dquot[cnt], number);
1262         }
1263         inode_sub_bytes(inode, number);
1264         spin_unlock(&dq_data_lock);
1265         /* Dirtify all the dquots - this can block when journalling */
1266         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1267                 if (inode->i_dquot[cnt])
1268                         mark_dquot_dirty(inode->i_dquot[cnt]);
1269         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1270         return QUOTA_OK;
1271 }
1272
1273 /*
1274  * This operation can block, but only after everything is updated
1275  */
1276 int dquot_free_inode(const struct inode *inode, unsigned long number)
1277 {
1278         unsigned int cnt;
1279
1280         /* First test before acquiring mutex - solves deadlocks when we
1281          * re-enter the quota code and are already holding the mutex */
1282         if (IS_NOQUOTA(inode))
1283                 return QUOTA_OK;
1284         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1285         /* Now recheck reliably when holding dqptr_sem */
1286         if (IS_NOQUOTA(inode)) {
1287                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1288                 return QUOTA_OK;
1289         }
1290         spin_lock(&dq_data_lock);
1291         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1292                 if (inode->i_dquot[cnt] == NODQUOT)
1293                         continue;
1294                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1295         }
1296         spin_unlock(&dq_data_lock);
1297         /* Dirtify all the dquots - this can block when journalling */
1298         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1299                 if (inode->i_dquot[cnt])
1300                         mark_dquot_dirty(inode->i_dquot[cnt]);
1301         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1302         return QUOTA_OK;
1303 }
1304
1305 /*
1306  * Transfer the number of inode and blocks from one diskquota to an other.
1307  *
1308  * This operation can block, but only after everything is updated
1309  * A transaction must be started when entering this function.
1310  */
1311 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1312 {
1313         qsize_t space;
1314         struct dquot *transfer_from[MAXQUOTAS];
1315         struct dquot *transfer_to[MAXQUOTAS];
1316         int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
1317             chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
1318         char warntype[MAXQUOTAS];
1319
1320         /* First test before acquiring mutex - solves deadlocks when we
1321          * re-enter the quota code and are already holding the mutex */
1322         if (IS_NOQUOTA(inode))
1323                 return QUOTA_OK;
1324         /* Clear the arrays */
1325         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1326                 transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
1327                 warntype[cnt] = QUOTA_NL_NOWARN;
1328         }
1329         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1330         /* Now recheck reliably when holding dqptr_sem */
1331         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1332                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1333                 return QUOTA_OK;
1334         }
1335         /* First build the transfer_to list - here we can block on
1336          * reading/instantiating of dquots.  We know that the transaction for
1337          * us was already started so we don't violate lock ranking here */
1338         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1339                 switch (cnt) {
1340                         case USRQUOTA:
1341                                 if (!chuid)
1342                                         continue;
1343                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1344                                 break;
1345                         case GRPQUOTA:
1346                                 if (!chgid)
1347                                         continue;
1348                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1349                                 break;
1350                 }
1351         }
1352         spin_lock(&dq_data_lock);
1353         space = inode_get_bytes(inode);
1354         /* Build the transfer_from list and check the limits */
1355         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1356                 if (transfer_to[cnt] == NODQUOT)
1357                         continue;
1358                 transfer_from[cnt] = inode->i_dquot[cnt];
1359                 if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
1360                     check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
1361                         goto warn_put_all;
1362         }
1363
1364         /*
1365          * Finally perform the needed transfer from transfer_from to transfer_to
1366          */
1367         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1368                 /*
1369                  * Skip changes for same uid or gid or for turned off quota-type.
1370                  */
1371                 if (transfer_to[cnt] == NODQUOT)
1372                         continue;
1373
1374                 /* Due to IO error we might not have transfer_from[] structure */
1375                 if (transfer_from[cnt]) {
1376                         dquot_decr_inodes(transfer_from[cnt], 1);
1377                         dquot_decr_space(transfer_from[cnt], space);
1378                 }
1379
1380                 dquot_incr_inodes(transfer_to[cnt], 1);
1381                 dquot_incr_space(transfer_to[cnt], space);
1382
1383                 inode->i_dquot[cnt] = transfer_to[cnt];
1384         }
1385         ret = QUOTA_OK;
1386 warn_put_all:
1387         spin_unlock(&dq_data_lock);
1388         /* Dirtify all the dquots - this can block when journalling */
1389         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1390                 if (transfer_from[cnt])
1391                         mark_dquot_dirty(transfer_from[cnt]);
1392                 if (transfer_to[cnt])
1393                         mark_dquot_dirty(transfer_to[cnt]);
1394         }
1395         flush_warnings(transfer_to, warntype);
1396         
1397         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1398                 if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
1399                         dqput(transfer_from[cnt]);
1400                 if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
1401                         dqput(transfer_to[cnt]);
1402         }
1403         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1404         return ret;
1405 }
1406
1407 /*
1408  * Write info of quota file to disk
1409  */
1410 int dquot_commit_info(struct super_block *sb, int type)
1411 {
1412         int ret;
1413         struct quota_info *dqopt = sb_dqopt(sb);
1414
1415         mutex_lock(&dqopt->dqio_mutex);
1416         ret = dqopt->ops[type]->write_file_info(sb, type);
1417         mutex_unlock(&dqopt->dqio_mutex);
1418         return ret;
1419 }
1420
1421 /*
1422  * Definitions of diskquota operations.
1423  */
1424 struct dquot_operations dquot_operations = {
1425         .initialize     = dquot_initialize,
1426         .drop           = dquot_drop,
1427         .alloc_space    = dquot_alloc_space,
1428         .alloc_inode    = dquot_alloc_inode,
1429         .free_space     = dquot_free_space,
1430         .free_inode     = dquot_free_inode,
1431         .transfer       = dquot_transfer,
1432         .write_dquot    = dquot_commit,
1433         .acquire_dquot  = dquot_acquire,
1434         .release_dquot  = dquot_release,
1435         .mark_dirty     = dquot_mark_dquot_dirty,
1436         .write_info     = dquot_commit_info
1437 };
1438
1439 static inline void set_enable_flags(struct quota_info *dqopt, int type)
1440 {
1441         switch (type) {
1442                 case USRQUOTA:
1443                         dqopt->flags |= DQUOT_USR_ENABLED;
1444                         break;
1445                 case GRPQUOTA:
1446                         dqopt->flags |= DQUOT_GRP_ENABLED;
1447                         break;
1448         }
1449 }
1450
1451 static inline void reset_enable_flags(struct quota_info *dqopt, int type)
1452 {
1453         switch (type) {
1454                 case USRQUOTA:
1455                         dqopt->flags &= ~DQUOT_USR_ENABLED;
1456                         break;
1457                 case GRPQUOTA:
1458                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
1459                         break;
1460         }
1461 }
1462
1463 /*
1464  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1465  */
1466 int vfs_quota_off(struct super_block *sb, int type)
1467 {
1468         int cnt;
1469         struct quota_info *dqopt = sb_dqopt(sb);
1470         struct inode *toputinode[MAXQUOTAS];
1471
1472         /* We need to serialize quota_off() for device */
1473         mutex_lock(&dqopt->dqonoff_mutex);
1474         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1475                 toputinode[cnt] = NULL;
1476                 if (type != -1 && cnt != type)
1477                         continue;
1478                 if (!sb_has_quota_enabled(sb, cnt))
1479                         continue;
1480                 reset_enable_flags(dqopt, cnt);
1481
1482                 /* Note: these are blocking operations */
1483                 drop_dquot_ref(sb, cnt);
1484                 invalidate_dquots(sb, cnt);
1485                 /*
1486                  * Now all dquots should be invalidated, all writes done so we should be only
1487                  * users of the info. No locks needed.
1488                  */
1489                 if (info_dirty(&dqopt->info[cnt]))
1490                         sb->dq_op->write_info(sb, cnt);
1491                 if (dqopt->ops[cnt]->free_file_info)
1492                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1493                 put_quota_format(dqopt->info[cnt].dqi_format);
1494
1495                 toputinode[cnt] = dqopt->files[cnt];
1496                 dqopt->files[cnt] = NULL;
1497                 dqopt->info[cnt].dqi_flags = 0;
1498                 dqopt->info[cnt].dqi_igrace = 0;
1499                 dqopt->info[cnt].dqi_bgrace = 0;
1500                 dqopt->ops[cnt] = NULL;
1501         }
1502         mutex_unlock(&dqopt->dqonoff_mutex);
1503         /* Sync the superblock so that buffers with quota data are written to
1504          * disk (and so userspace sees correct data afterwards). */
1505         if (sb->s_op->sync_fs)
1506                 sb->s_op->sync_fs(sb, 1);
1507         sync_blockdev(sb->s_bdev);
1508         /* Now the quota files are just ordinary files and we can set the
1509          * inode flags back. Moreover we discard the pagecache so that
1510          * userspace sees the writes we did bypassing the pagecache. We
1511          * must also discard the blockdev buffers so that we see the
1512          * changes done by userspace on the next quotaon() */
1513         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1514                 if (toputinode[cnt]) {
1515                         mutex_lock(&dqopt->dqonoff_mutex);
1516                         /* If quota was reenabled in the meantime, we have
1517                          * nothing to do */
1518                         if (!sb_has_quota_enabled(sb, cnt)) {
1519                                 mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
1520                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1521                                   S_NOATIME | S_NOQUOTA);
1522                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1523                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1524                                 mark_inode_dirty(toputinode[cnt]);
1525                                 iput(toputinode[cnt]);
1526                         }
1527                         mutex_unlock(&dqopt->dqonoff_mutex);
1528                 }
1529         if (sb->s_bdev)
1530                 invalidate_bdev(sb->s_bdev);
1531         return 0;
1532 }
1533
1534 /*
1535  *      Turn quotas on on a device
1536  */
1537
1538 /* Helper function when we already have the inode */
1539 static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
1540 {
1541         struct quota_format_type *fmt = find_quota_format(format_id);
1542         struct super_block *sb = inode->i_sb;
1543         struct quota_info *dqopt = sb_dqopt(sb);
1544         int error;
1545         int oldflags = -1;
1546
1547         if (!fmt)
1548                 return -ESRCH;
1549         if (!S_ISREG(inode->i_mode)) {
1550                 error = -EACCES;
1551                 goto out_fmt;
1552         }
1553         if (IS_RDONLY(inode)) {
1554                 error = -EROFS;
1555                 goto out_fmt;
1556         }
1557         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1558                 error = -EINVAL;
1559                 goto out_fmt;
1560         }
1561
1562         /* As we bypass the pagecache we must now flush the inode so that
1563          * we see all the changes from userspace... */
1564         write_inode_now(inode, 1);
1565         /* And now flush the block cache so that kernel sees the changes */
1566         invalidate_bdev(sb->s_bdev);
1567         mutex_lock(&inode->i_mutex);
1568         mutex_lock(&dqopt->dqonoff_mutex);
1569         if (sb_has_quota_enabled(sb, type)) {
1570                 error = -EBUSY;
1571                 goto out_lock;
1572         }
1573         /* We don't want quota and atime on quota files (deadlocks possible)
1574          * Also nobody should write to the file - we use special IO operations
1575          * which ignore the immutable bit. */
1576         down_write(&dqopt->dqptr_sem);
1577         oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1578         inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1579         up_write(&dqopt->dqptr_sem);
1580         sb->dq_op->drop(inode);
1581
1582         error = -EIO;
1583         dqopt->files[type] = igrab(inode);
1584         if (!dqopt->files[type])
1585                 goto out_lock;
1586         error = -EINVAL;
1587         if (!fmt->qf_ops->check_quota_file(sb, type))
1588                 goto out_file_init;
1589
1590         dqopt->ops[type] = fmt->qf_ops;
1591         dqopt->info[type].dqi_format = fmt;
1592         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1593         mutex_lock(&dqopt->dqio_mutex);
1594         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1595                 mutex_unlock(&dqopt->dqio_mutex);
1596                 goto out_file_init;
1597         }
1598         mutex_unlock(&dqopt->dqio_mutex);
1599         mutex_unlock(&inode->i_mutex);
1600         set_enable_flags(dqopt, type);
1601
1602         add_dquot_ref(sb, type);
1603         mutex_unlock(&dqopt->dqonoff_mutex);
1604
1605         return 0;
1606
1607 out_file_init:
1608         dqopt->files[type] = NULL;
1609         iput(inode);
1610 out_lock:
1611         mutex_unlock(&dqopt->dqonoff_mutex);
1612         if (oldflags != -1) {
1613                 down_write(&dqopt->dqptr_sem);
1614                 /* Set the flags back (in the case of accidental quotaon()
1615                  * on a wrong file we don't want to mess up the flags) */
1616                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1617                 inode->i_flags |= oldflags;
1618                 up_write(&dqopt->dqptr_sem);
1619         }
1620         mutex_unlock(&inode->i_mutex);
1621 out_fmt:
1622         put_quota_format(fmt);
1623
1624         return error; 
1625 }
1626
1627 /* Actual function called from quotactl() */
1628 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
1629 {
1630         struct nameidata nd;
1631         int error;
1632
1633         error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1634         if (error < 0)
1635                 return error;
1636         error = security_quota_on(nd.path.dentry);
1637         if (error)
1638                 goto out_path;
1639         /* Quota file not on the same filesystem? */
1640         if (nd.path.mnt->mnt_sb != sb)
1641                 error = -EXDEV;
1642         else
1643                 error = vfs_quota_on_inode(nd.path.dentry->d_inode, type,
1644                                            format_id);
1645 out_path:
1646         path_put(&nd.path);
1647         return error;
1648 }
1649
1650 /*
1651  * This function is used when filesystem needs to initialize quotas
1652  * during mount time.
1653  */
1654 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
1655                 int format_id, int type)
1656 {
1657         struct dentry *dentry;
1658         int error;
1659
1660         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
1661         if (IS_ERR(dentry))
1662                 return PTR_ERR(dentry);
1663
1664         if (!dentry->d_inode) {
1665                 error = -ENOENT;
1666                 goto out;
1667         }
1668
1669         error = security_quota_on(dentry);
1670         if (!error)
1671                 error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
1672
1673 out:
1674         dput(dentry);
1675         return error;
1676 }
1677
1678 /* Generic routine for getting common part of quota structure */
1679 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
1680 {
1681         struct mem_dqblk *dm = &dquot->dq_dqb;
1682
1683         spin_lock(&dq_data_lock);
1684         di->dqb_bhardlimit = dm->dqb_bhardlimit;
1685         di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
1686         di->dqb_curspace = dm->dqb_curspace;
1687         di->dqb_ihardlimit = dm->dqb_ihardlimit;
1688         di->dqb_isoftlimit = dm->dqb_isoftlimit;
1689         di->dqb_curinodes = dm->dqb_curinodes;
1690         di->dqb_btime = dm->dqb_btime;
1691         di->dqb_itime = dm->dqb_itime;
1692         di->dqb_valid = QIF_ALL;
1693         spin_unlock(&dq_data_lock);
1694 }
1695
1696 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1697 {
1698         struct dquot *dquot;
1699
1700         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1701         if (!(dquot = dqget(sb, id, type))) {
1702                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1703                 return -ESRCH;
1704         }
1705         do_get_dqblk(dquot, di);
1706         dqput(dquot);
1707         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1708         return 0;
1709 }
1710
1711 /* Generic routine for setting common part of quota structure */
1712 static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
1713 {
1714         struct mem_dqblk *dm = &dquot->dq_dqb;
1715         int check_blim = 0, check_ilim = 0;
1716
1717         spin_lock(&dq_data_lock);
1718         if (di->dqb_valid & QIF_SPACE) {
1719                 dm->dqb_curspace = di->dqb_curspace;
1720                 check_blim = 1;
1721         }
1722         if (di->dqb_valid & QIF_BLIMITS) {
1723                 dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
1724                 dm->dqb_bhardlimit = di->dqb_bhardlimit;
1725                 check_blim = 1;
1726         }
1727         if (di->dqb_valid & QIF_INODES) {
1728                 dm->dqb_curinodes = di->dqb_curinodes;
1729                 check_ilim = 1;
1730         }
1731         if (di->dqb_valid & QIF_ILIMITS) {
1732                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
1733                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
1734                 check_ilim = 1;
1735         }
1736         if (di->dqb_valid & QIF_BTIME)
1737                 dm->dqb_btime = di->dqb_btime;
1738         if (di->dqb_valid & QIF_ITIME)
1739                 dm->dqb_itime = di->dqb_itime;
1740
1741         if (check_blim) {
1742                 if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
1743                         dm->dqb_btime = 0;
1744                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1745                 }
1746                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
1747                         dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1748         }
1749         if (check_ilim) {
1750                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
1751                         dm->dqb_itime = 0;
1752                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1753                 }
1754                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
1755                         dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1756         }
1757         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
1758                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
1759         else
1760                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
1761         spin_unlock(&dq_data_lock);
1762         mark_dquot_dirty(dquot);
1763 }
1764
1765 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1766 {
1767         struct dquot *dquot;
1768
1769         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1770         if (!(dquot = dqget(sb, id, type))) {
1771                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1772                 return -ESRCH;
1773         }
1774         do_set_dqblk(dquot, di);
1775         dqput(dquot);
1776         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1777         return 0;
1778 }
1779
1780 /* Generic routine for getting common part of quota file information */
1781 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1782 {
1783         struct mem_dqinfo *mi;
1784   
1785         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1786         if (!sb_has_quota_enabled(sb, type)) {
1787                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1788                 return -ESRCH;
1789         }
1790         mi = sb_dqopt(sb)->info + type;
1791         spin_lock(&dq_data_lock);
1792         ii->dqi_bgrace = mi->dqi_bgrace;
1793         ii->dqi_igrace = mi->dqi_igrace;
1794         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
1795         ii->dqi_valid = IIF_ALL;
1796         spin_unlock(&dq_data_lock);
1797         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1798         return 0;
1799 }
1800
1801 /* Generic routine for setting common part of quota file information */
1802 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1803 {
1804         struct mem_dqinfo *mi;
1805
1806         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
1807         if (!sb_has_quota_enabled(sb, type)) {
1808                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1809                 return -ESRCH;
1810         }
1811         mi = sb_dqopt(sb)->info + type;
1812         spin_lock(&dq_data_lock);
1813         if (ii->dqi_valid & IIF_BGRACE)
1814                 mi->dqi_bgrace = ii->dqi_bgrace;
1815         if (ii->dqi_valid & IIF_IGRACE)
1816                 mi->dqi_igrace = ii->dqi_igrace;
1817         if (ii->dqi_valid & IIF_FLAGS)
1818                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
1819         spin_unlock(&dq_data_lock);
1820         mark_info_dirty(sb, type);
1821         /* Force write to disk */
1822         sb->dq_op->write_info(sb, type);
1823         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
1824         return 0;
1825 }
1826
1827 struct quotactl_ops vfs_quotactl_ops = {
1828         .quota_on       = vfs_quota_on,
1829         .quota_off      = vfs_quota_off,
1830         .quota_sync     = vfs_quota_sync,
1831         .get_info       = vfs_get_dqinfo,
1832         .set_info       = vfs_set_dqinfo,
1833         .get_dqblk      = vfs_get_dqblk,
1834         .set_dqblk      = vfs_set_dqblk
1835 };
1836
1837 static ctl_table fs_dqstats_table[] = {
1838         {
1839                 .ctl_name       = FS_DQ_LOOKUPS,
1840                 .procname       = "lookups",
1841                 .data           = &dqstats.lookups,
1842                 .maxlen         = sizeof(int),
1843                 .mode           = 0444,
1844                 .proc_handler   = &proc_dointvec,
1845         },
1846         {
1847                 .ctl_name       = FS_DQ_DROPS,
1848                 .procname       = "drops",
1849                 .data           = &dqstats.drops,
1850                 .maxlen         = sizeof(int),
1851                 .mode           = 0444,
1852                 .proc_handler   = &proc_dointvec,
1853         },
1854         {
1855                 .ctl_name       = FS_DQ_READS,
1856                 .procname       = "reads",
1857                 .data           = &dqstats.reads,
1858                 .maxlen         = sizeof(int),
1859                 .mode           = 0444,
1860                 .proc_handler   = &proc_dointvec,
1861         },
1862         {
1863                 .ctl_name       = FS_DQ_WRITES,
1864                 .procname       = "writes",
1865                 .data           = &dqstats.writes,
1866                 .maxlen         = sizeof(int),
1867                 .mode           = 0444,
1868                 .proc_handler   = &proc_dointvec,
1869         },
1870         {
1871                 .ctl_name       = FS_DQ_CACHE_HITS,
1872                 .procname       = "cache_hits",
1873                 .data           = &dqstats.cache_hits,
1874                 .maxlen         = sizeof(int),
1875                 .mode           = 0444,
1876                 .proc_handler   = &proc_dointvec,
1877         },
1878         {
1879                 .ctl_name       = FS_DQ_ALLOCATED,
1880                 .procname       = "allocated_dquots",
1881                 .data           = &dqstats.allocated_dquots,
1882                 .maxlen         = sizeof(int),
1883                 .mode           = 0444,
1884                 .proc_handler   = &proc_dointvec,
1885         },
1886         {
1887                 .ctl_name       = FS_DQ_FREE,
1888                 .procname       = "free_dquots",
1889                 .data           = &dqstats.free_dquots,
1890                 .maxlen         = sizeof(int),
1891                 .mode           = 0444,
1892                 .proc_handler   = &proc_dointvec,
1893         },
1894         {
1895                 .ctl_name       = FS_DQ_SYNCS,
1896                 .procname       = "syncs",
1897                 .data           = &dqstats.syncs,
1898                 .maxlen         = sizeof(int),
1899                 .mode           = 0444,
1900                 .proc_handler   = &proc_dointvec,
1901         },
1902 #ifdef CONFIG_PRINT_QUOTA_WARNING
1903         {
1904                 .ctl_name       = FS_DQ_WARNINGS,
1905                 .procname       = "warnings",
1906                 .data           = &flag_print_warnings,
1907                 .maxlen         = sizeof(int),
1908                 .mode           = 0644,
1909                 .proc_handler   = &proc_dointvec,
1910         },
1911 #endif
1912         { .ctl_name = 0 },
1913 };
1914
1915 static ctl_table fs_table[] = {
1916         {
1917                 .ctl_name       = FS_DQSTATS,
1918                 .procname       = "quota",
1919                 .mode           = 0555,
1920                 .child          = fs_dqstats_table,
1921         },
1922         { .ctl_name = 0 },
1923 };
1924
1925 static ctl_table sys_table[] = {
1926         {
1927                 .ctl_name       = CTL_FS,
1928                 .procname       = "fs",
1929                 .mode           = 0555,
1930                 .child          = fs_table,
1931         },
1932         { .ctl_name = 0 },
1933 };
1934
1935 static int __init dquot_init(void)
1936 {
1937         int i;
1938         unsigned long nr_hash, order;
1939
1940         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
1941
1942         register_sysctl_table(sys_table);
1943
1944         dquot_cachep = kmem_cache_create("dquot",
1945                         sizeof(struct dquot), sizeof(unsigned long) * 4,
1946                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1947                                 SLAB_MEM_SPREAD|SLAB_PANIC),
1948                         NULL);
1949
1950         order = 0;
1951         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
1952         if (!dquot_hash)
1953                 panic("Cannot create dquot hash table");
1954
1955         /* Find power-of-two hlist_heads which can fit into allocation */
1956         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
1957         dq_hash_bits = 0;
1958         do {
1959                 dq_hash_bits++;
1960         } while (nr_hash >> dq_hash_bits);
1961         dq_hash_bits--;
1962
1963         nr_hash = 1UL << dq_hash_bits;
1964         dq_hash_mask = nr_hash - 1;
1965         for (i = 0; i < nr_hash; i++)
1966                 INIT_HLIST_HEAD(dquot_hash + i);
1967
1968         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
1969                         nr_hash, order, (PAGE_SIZE << order));
1970
1971         register_shrinker(&dqcache_shrinker);
1972
1973 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
1974         if (genl_register_family(&quota_genl_family) != 0)
1975                 printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
1976 #endif
1977
1978         return 0;
1979 }
1980 module_init(dquot_init);
1981
1982 EXPORT_SYMBOL(register_quota_format);
1983 EXPORT_SYMBOL(unregister_quota_format);
1984 EXPORT_SYMBOL(dqstats);
1985 EXPORT_SYMBOL(dq_data_lock);
1986 EXPORT_SYMBOL(vfs_quota_on);
1987 EXPORT_SYMBOL(vfs_quota_on_mount);
1988 EXPORT_SYMBOL(vfs_quota_off);
1989 EXPORT_SYMBOL(vfs_quota_sync);
1990 EXPORT_SYMBOL(vfs_get_dqinfo);
1991 EXPORT_SYMBOL(vfs_set_dqinfo);
1992 EXPORT_SYMBOL(vfs_get_dqblk);
1993 EXPORT_SYMBOL(vfs_set_dqblk);
1994 EXPORT_SYMBOL(dquot_commit);
1995 EXPORT_SYMBOL(dquot_commit_info);
1996 EXPORT_SYMBOL(dquot_acquire);
1997 EXPORT_SYMBOL(dquot_release);
1998 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
1999 EXPORT_SYMBOL(dquot_initialize);
2000 EXPORT_SYMBOL(dquot_drop);
2001 EXPORT_SYMBOL(dquot_alloc_space);
2002 EXPORT_SYMBOL(dquot_alloc_inode);
2003 EXPORT_SYMBOL(dquot_free_space);
2004 EXPORT_SYMBOL(dquot_free_inode);
2005 EXPORT_SYMBOL(dquot_transfer);