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[J-linux.git] / fs / quota / dquot.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Implementation of the diskquota system for the LINUX operating system. QUOTA
4  * is implemented using the BSD system call interface as the means of
5  * communication with the user level. This file contains the generic routines
6  * called by the different filesystems on allocation of an inode or block.
7  * These routines take care of the administration needed to have a consistent
8  * diskquota tracking system. The ideas of both user and group quotas are based
9  * on the Melbourne quota system as used on BSD derived systems. The internal
10  * implementation is based on one of the several variants of the LINUX
11  * inode-subsystem with added complexity of the diskquota system.
12  *
13  * Author:      Marco van Wieringen <[email protected]>
14  *
15  * Fixes:   Dmitry Gorodchanin <[email protected]>, 11 Feb 96
16  *
17  *              Revised list management to avoid races
18  *              -- Bill Hawes, <[email protected]>, 9/98
19  *
20  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
21  *              As the consequence the locking was moved from dquot_decr_...(),
22  *              dquot_incr_...() to calling functions.
23  *              invalidate_dquots() now writes modified dquots.
24  *              Serialized quota_off() and quota_on() for mount point.
25  *              Fixed a few bugs in grow_dquots().
26  *              Fixed deadlock in write_dquot() - we no longer account quotas on
27  *              quota files
28  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
29  *              add_dquot_ref() restarts after blocking
30  *              Added check for bogus uid and fixed check for group in quotactl.
31  *              Jan Kara, <[email protected]>, sponsored by SuSE CR, 10-11/99
32  *
33  *              Used struct list_head instead of own list struct
34  *              Invalidation of referenced dquots is no longer possible
35  *              Improved free_dquots list management
36  *              Quota and i_blocks are now updated in one place to avoid races
37  *              Warnings are now delayed so we won't block in critical section
38  *              Write updated not to require dquot lock
39  *              Jan Kara, <[email protected]>, 9/2000
40  *
41  *              Added dynamic quota structure allocation
42  *              Jan Kara <[email protected]> 12/2000
43  *
44  *              Rewritten quota interface. Implemented new quota format and
45  *              formats registering.
46  *              Jan Kara, <[email protected]>, 2001,2002
47  *
48  *              New SMP locking.
49  *              Jan Kara, <[email protected]>, 10/2002
50  *
51  *              Added journalled quota support, fix lock inversion problems
52  *              Jan Kara, <[email protected]>, 2003,2004
53  *
54  * (C) Copyright 1994 - 1997 Marco van Wieringen
55  */
56
57 #include <linux/errno.h>
58 #include <linux/kernel.h>
59 #include <linux/fs.h>
60 #include <linux/mount.h>
61 #include <linux/mm.h>
62 #include <linux/time.h>
63 #include <linux/types.h>
64 #include <linux/string.h>
65 #include <linux/fcntl.h>
66 #include <linux/stat.h>
67 #include <linux/tty.h>
68 #include <linux/file.h>
69 #include <linux/slab.h>
70 #include <linux/sysctl.h>
71 #include <linux/init.h>
72 #include <linux/module.h>
73 #include <linux/proc_fs.h>
74 #include <linux/security.h>
75 #include <linux/sched.h>
76 #include <linux/cred.h>
77 #include <linux/kmod.h>
78 #include <linux/namei.h>
79 #include <linux/capability.h>
80 #include <linux/quotaops.h>
81 #include <linux/blkdev.h>
82 #include <linux/sched/mm.h>
83
84 #include <linux/uaccess.h>
85
86 /*
87  * There are five quota SMP locks:
88  * * dq_list_lock protects all lists with quotas and quota formats.
89  * * dquot->dq_dqb_lock protects data from dq_dqb
90  * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
91  *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
92  *   dquot_transfer() can stabilize amount it transfers
93  * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
94  *   pointers in the inode
95  * * dq_state_lock protects modifications of quota state (on quotaon and
96  *   quotaoff) and readers who care about latest values take it as well.
97  *
98  * The spinlock ordering is hence:
99  *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
100  *   dq_list_lock > dq_state_lock
101  *
102  * Note that some things (eg. sb pointer, type, id) doesn't change during
103  * the life of the dquot structure and so needn't to be protected by a lock
104  *
105  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
106  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
107  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
108  * inode and before dropping dquot references to avoid use of dquots after
109  * they are freed. dq_data_lock is used to serialize the pointer setting and
110  * clearing operations.
111  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
112  * inode is a quota file). Functions adding pointers from inode to dquots have
113  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
114  * have to do all pointer modifications before dropping dq_data_lock. This makes
115  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
116  * then drops all pointers to dquots from an inode.
117  *
118  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
119  * memory (or space for it is being allocated) on the first dqget(), when it is
120  * being written out, and when it is being released on the last dqput(). The
121  * allocation and release operations are serialized by the dq_lock and by
122  * checking the use count in dquot_release().
123  *
124  * Lock ordering (including related VFS locks) is the following:
125  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
126  */
127
128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
129 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
130 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
131 EXPORT_SYMBOL(dq_data_lock);
132 DEFINE_STATIC_SRCU(dquot_srcu);
133
134 static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
135
136 void __quota_error(struct super_block *sb, const char *func,
137                    const char *fmt, ...)
138 {
139         if (printk_ratelimit()) {
140                 va_list args;
141                 struct va_format vaf;
142
143                 va_start(args, fmt);
144
145                 vaf.fmt = fmt;
146                 vaf.va = &args;
147
148                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
149                        sb->s_id, func, &vaf);
150
151                 va_end(args);
152         }
153 }
154 EXPORT_SYMBOL(__quota_error);
155
156 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
157 static char *quotatypes[] = INITQFNAMES;
158 #endif
159 static struct quota_format_type *quota_formats; /* List of registered formats */
160 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
161
162 /* SLAB cache for dquot structures */
163 static struct kmem_cache *dquot_cachep;
164
165 void register_quota_format(struct quota_format_type *fmt)
166 {
167         spin_lock(&dq_list_lock);
168         fmt->qf_next = quota_formats;
169         quota_formats = fmt;
170         spin_unlock(&dq_list_lock);
171 }
172 EXPORT_SYMBOL(register_quota_format);
173
174 void unregister_quota_format(struct quota_format_type *fmt)
175 {
176         struct quota_format_type **actqf;
177
178         spin_lock(&dq_list_lock);
179         for (actqf = &quota_formats; *actqf && *actqf != fmt;
180              actqf = &(*actqf)->qf_next)
181                 ;
182         if (*actqf)
183                 *actqf = (*actqf)->qf_next;
184         spin_unlock(&dq_list_lock);
185 }
186 EXPORT_SYMBOL(unregister_quota_format);
187
188 static struct quota_format_type *find_quota_format(int id)
189 {
190         struct quota_format_type *actqf;
191
192         spin_lock(&dq_list_lock);
193         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
194              actqf = actqf->qf_next)
195                 ;
196         if (!actqf || !try_module_get(actqf->qf_owner)) {
197                 int qm;
198
199                 spin_unlock(&dq_list_lock);
200
201                 for (qm = 0; module_names[qm].qm_fmt_id &&
202                              module_names[qm].qm_fmt_id != id; qm++)
203                         ;
204                 if (!module_names[qm].qm_fmt_id ||
205                     request_module(module_names[qm].qm_mod_name))
206                         return NULL;
207
208                 spin_lock(&dq_list_lock);
209                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
210                      actqf = actqf->qf_next)
211                         ;
212                 if (actqf && !try_module_get(actqf->qf_owner))
213                         actqf = NULL;
214         }
215         spin_unlock(&dq_list_lock);
216         return actqf;
217 }
218
219 static void put_quota_format(struct quota_format_type *fmt)
220 {
221         module_put(fmt->qf_owner);
222 }
223
224 /*
225  * Dquot List Management:
226  * The quota code uses five lists for dquot management: the inuse_list,
227  * releasing_dquots, free_dquots, dqi_dirty_list, and dquot_hash[] array.
228  * A single dquot structure may be on some of those lists, depending on
229  * its current state.
230  *
231  * All dquots are placed to the end of inuse_list when first created, and this
232  * list is used for invalidate operation, which must look at every dquot.
233  *
234  * When the last reference of a dquot is dropped, the dquot is added to
235  * releasing_dquots. We'll then queue work item which will call
236  * synchronize_srcu() and after that perform the final cleanup of all the
237  * dquots on the list. Each cleaned up dquot is moved to free_dquots list.
238  * Both releasing_dquots and free_dquots use the dq_free list_head in the dquot
239  * struct.
240  *
241  * Unused and cleaned up dquots are in the free_dquots list and this list is
242  * searched whenever we need an available dquot. Dquots are removed from the
243  * list as soon as they are used again and dqstats.free_dquots gives the number
244  * of dquots on the list. When dquot is invalidated it's completely released
245  * from memory.
246  *
247  * Dirty dquots are added to the dqi_dirty_list of quota_info when mark
248  * dirtied, and this list is searched when writing dirty dquots back to
249  * quota file. Note that some filesystems do dirty dquot tracking on their
250  * own (e.g. in a journal) and thus don't use dqi_dirty_list.
251  *
252  * Dquots with a specific identity (device, type and id) are placed on
253  * one of the dquot_hash[] hash chains. The provides an efficient search
254  * mechanism to locate a specific dquot.
255  */
256
257 static LIST_HEAD(inuse_list);
258 static LIST_HEAD(free_dquots);
259 static LIST_HEAD(releasing_dquots);
260 static unsigned int dq_hash_bits, dq_hash_mask;
261 static struct hlist_head *dquot_hash;
262
263 struct dqstats dqstats;
264 EXPORT_SYMBOL(dqstats);
265
266 static qsize_t inode_get_rsv_space(struct inode *inode);
267 static qsize_t __inode_get_rsv_space(struct inode *inode);
268 static int __dquot_initialize(struct inode *inode, int type);
269
270 static void quota_release_workfn(struct work_struct *work);
271 static DECLARE_DELAYED_WORK(quota_release_work, quota_release_workfn);
272
273 static inline unsigned int
274 hashfn(const struct super_block *sb, struct kqid qid)
275 {
276         unsigned int id = from_kqid(&init_user_ns, qid);
277         int type = qid.type;
278         unsigned long tmp;
279
280         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
281         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
282 }
283
284 /*
285  * Following list functions expect dq_list_lock to be held
286  */
287 static inline void insert_dquot_hash(struct dquot *dquot)
288 {
289         struct hlist_head *head;
290         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
291         hlist_add_head(&dquot->dq_hash, head);
292 }
293
294 static inline void remove_dquot_hash(struct dquot *dquot)
295 {
296         hlist_del_init(&dquot->dq_hash);
297 }
298
299 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
300                                 struct kqid qid)
301 {
302         struct dquot *dquot;
303
304         hlist_for_each_entry(dquot, dquot_hash+hashent, dq_hash)
305                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
306                         return dquot;
307
308         return NULL;
309 }
310
311 /* Add a dquot to the tail of the free list */
312 static inline void put_dquot_last(struct dquot *dquot)
313 {
314         list_add_tail(&dquot->dq_free, &free_dquots);
315         dqstats_inc(DQST_FREE_DQUOTS);
316 }
317
318 static inline void put_releasing_dquots(struct dquot *dquot)
319 {
320         list_add_tail(&dquot->dq_free, &releasing_dquots);
321         set_bit(DQ_RELEASING_B, &dquot->dq_flags);
322 }
323
324 static inline void remove_free_dquot(struct dquot *dquot)
325 {
326         if (list_empty(&dquot->dq_free))
327                 return;
328         list_del_init(&dquot->dq_free);
329         if (!test_bit(DQ_RELEASING_B, &dquot->dq_flags))
330                 dqstats_dec(DQST_FREE_DQUOTS);
331         else
332                 clear_bit(DQ_RELEASING_B, &dquot->dq_flags);
333 }
334
335 static inline void put_inuse(struct dquot *dquot)
336 {
337         /* We add to the back of inuse list so we don't have to restart
338          * when traversing this list and we block */
339         list_add_tail(&dquot->dq_inuse, &inuse_list);
340         dqstats_inc(DQST_ALLOC_DQUOTS);
341 }
342
343 static inline void remove_inuse(struct dquot *dquot)
344 {
345         dqstats_dec(DQST_ALLOC_DQUOTS);
346         list_del(&dquot->dq_inuse);
347 }
348 /*
349  * End of list functions needing dq_list_lock
350  */
351
352 static void wait_on_dquot(struct dquot *dquot)
353 {
354         mutex_lock(&dquot->dq_lock);
355         mutex_unlock(&dquot->dq_lock);
356 }
357
358 static inline int dquot_active(struct dquot *dquot)
359 {
360         return test_bit(DQ_ACTIVE_B, &dquot->dq_flags);
361 }
362
363 static inline int dquot_dirty(struct dquot *dquot)
364 {
365         return test_bit(DQ_MOD_B, &dquot->dq_flags);
366 }
367
368 static inline int mark_dquot_dirty(struct dquot *dquot)
369 {
370         return dquot->dq_sb->dq_op->mark_dirty(dquot);
371 }
372
373 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
374 int dquot_mark_dquot_dirty(struct dquot *dquot)
375 {
376         int ret = 1;
377
378         if (!dquot_active(dquot))
379                 return 0;
380
381         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
382                 return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
383
384         /* If quota is dirty already, we don't have to acquire dq_list_lock */
385         if (dquot_dirty(dquot))
386                 return 1;
387
388         spin_lock(&dq_list_lock);
389         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
390                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
391                                 info[dquot->dq_id.type].dqi_dirty_list);
392                 ret = 0;
393         }
394         spin_unlock(&dq_list_lock);
395         return ret;
396 }
397 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
398
399 /* Dirtify all the dquots - this can block when journalling */
400 static inline int mark_all_dquot_dirty(struct dquot __rcu * const *dquots)
401 {
402         int ret, err, cnt;
403         struct dquot *dquot;
404
405         ret = err = 0;
406         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
407                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
408                 if (dquot)
409                         /* Even in case of error we have to continue */
410                         ret = mark_dquot_dirty(dquot);
411                 if (!err && ret < 0)
412                         err = ret;
413         }
414         return err;
415 }
416
417 static inline void dqput_all(struct dquot **dquot)
418 {
419         unsigned int cnt;
420
421         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
422                 dqput(dquot[cnt]);
423 }
424
425 static inline int clear_dquot_dirty(struct dquot *dquot)
426 {
427         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
428                 return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
429
430         spin_lock(&dq_list_lock);
431         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
432                 spin_unlock(&dq_list_lock);
433                 return 0;
434         }
435         list_del_init(&dquot->dq_dirty);
436         spin_unlock(&dq_list_lock);
437         return 1;
438 }
439
440 void mark_info_dirty(struct super_block *sb, int type)
441 {
442         spin_lock(&dq_data_lock);
443         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
444         spin_unlock(&dq_data_lock);
445 }
446 EXPORT_SYMBOL(mark_info_dirty);
447
448 /*
449  *      Read dquot from disk and alloc space for it
450  */
451
452 int dquot_acquire(struct dquot *dquot)
453 {
454         int ret = 0, ret2 = 0;
455         unsigned int memalloc;
456         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
457
458         mutex_lock(&dquot->dq_lock);
459         memalloc = memalloc_nofs_save();
460         if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
461                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
462                 if (ret < 0)
463                         goto out_iolock;
464         }
465         /* Make sure flags update is visible after dquot has been filled */
466         smp_mb__before_atomic();
467         set_bit(DQ_READ_B, &dquot->dq_flags);
468         /* Instantiate dquot if needed */
469         if (!dquot_active(dquot) && !dquot->dq_off) {
470                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
471                 /* Write the info if needed */
472                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
473                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
474                                         dquot->dq_sb, dquot->dq_id.type);
475                 }
476                 if (ret < 0)
477                         goto out_iolock;
478                 if (ret2 < 0) {
479                         ret = ret2;
480                         goto out_iolock;
481                 }
482         }
483         /*
484          * Make sure flags update is visible after on-disk struct has been
485          * allocated. Paired with smp_rmb() in dqget().
486          */
487         smp_mb__before_atomic();
488         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
489 out_iolock:
490         memalloc_nofs_restore(memalloc);
491         mutex_unlock(&dquot->dq_lock);
492         return ret;
493 }
494 EXPORT_SYMBOL(dquot_acquire);
495
496 /*
497  *      Write dquot to disk
498  */
499 int dquot_commit(struct dquot *dquot)
500 {
501         int ret = 0;
502         unsigned int memalloc;
503         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
504
505         mutex_lock(&dquot->dq_lock);
506         memalloc = memalloc_nofs_save();
507         if (!clear_dquot_dirty(dquot))
508                 goto out_lock;
509         /* Inactive dquot can be only if there was error during read/init
510          * => we have better not writing it */
511         if (dquot_active(dquot))
512                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
513         else
514                 ret = -EIO;
515 out_lock:
516         memalloc_nofs_restore(memalloc);
517         mutex_unlock(&dquot->dq_lock);
518         return ret;
519 }
520 EXPORT_SYMBOL(dquot_commit);
521
522 /*
523  *      Release dquot
524  */
525 int dquot_release(struct dquot *dquot)
526 {
527         int ret = 0, ret2 = 0;
528         unsigned int memalloc;
529         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
530
531         mutex_lock(&dquot->dq_lock);
532         memalloc = memalloc_nofs_save();
533         /* Check whether we are not racing with some other dqget() */
534         if (dquot_is_busy(dquot))
535                 goto out_dqlock;
536         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
537                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
538                 /* Write the info */
539                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
540                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
541                                                 dquot->dq_sb, dquot->dq_id.type);
542                 }
543                 if (ret >= 0)
544                         ret = ret2;
545         }
546         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
547 out_dqlock:
548         memalloc_nofs_restore(memalloc);
549         mutex_unlock(&dquot->dq_lock);
550         return ret;
551 }
552 EXPORT_SYMBOL(dquot_release);
553
554 void dquot_destroy(struct dquot *dquot)
555 {
556         kmem_cache_free(dquot_cachep, dquot);
557 }
558 EXPORT_SYMBOL(dquot_destroy);
559
560 static inline void do_destroy_dquot(struct dquot *dquot)
561 {
562         dquot->dq_sb->dq_op->destroy_dquot(dquot);
563 }
564
565 /* Invalidate all dquots on the list. Note that this function is called after
566  * quota is disabled and pointers from inodes removed so there cannot be new
567  * quota users. There can still be some users of quotas due to inodes being
568  * just deleted or pruned by prune_icache() (those are not attached to any
569  * list) or parallel quotactl call. We have to wait for such users.
570  */
571 static void invalidate_dquots(struct super_block *sb, int type)
572 {
573         struct dquot *dquot, *tmp;
574
575 restart:
576         flush_delayed_work(&quota_release_work);
577
578         spin_lock(&dq_list_lock);
579         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
580                 if (dquot->dq_sb != sb)
581                         continue;
582                 if (dquot->dq_id.type != type)
583                         continue;
584                 /* Wait for dquot users */
585                 if (atomic_read(&dquot->dq_count)) {
586                         atomic_inc(&dquot->dq_count);
587                         spin_unlock(&dq_list_lock);
588                         /*
589                          * Once dqput() wakes us up, we know it's time to free
590                          * the dquot.
591                          * IMPORTANT: we rely on the fact that there is always
592                          * at most one process waiting for dquot to free.
593                          * Otherwise dq_count would be > 1 and we would never
594                          * wake up.
595                          */
596                         wait_event(dquot_ref_wq,
597                                    atomic_read(&dquot->dq_count) == 1);
598                         dqput(dquot);
599                         /* At this moment dquot() need not exist (it could be
600                          * reclaimed by prune_dqcache(). Hence we must
601                          * restart. */
602                         goto restart;
603                 }
604                 /*
605                  * The last user already dropped its reference but dquot didn't
606                  * get fully cleaned up yet. Restart the scan which flushes the
607                  * work cleaning up released dquots.
608                  */
609                 if (test_bit(DQ_RELEASING_B, &dquot->dq_flags)) {
610                         spin_unlock(&dq_list_lock);
611                         goto restart;
612                 }
613                 /*
614                  * Quota now has no users and it has been written on last
615                  * dqput()
616                  */
617                 remove_dquot_hash(dquot);
618                 remove_free_dquot(dquot);
619                 remove_inuse(dquot);
620                 do_destroy_dquot(dquot);
621         }
622         spin_unlock(&dq_list_lock);
623 }
624
625 /* Call callback for every active dquot on given filesystem */
626 int dquot_scan_active(struct super_block *sb,
627                       int (*fn)(struct dquot *dquot, unsigned long priv),
628                       unsigned long priv)
629 {
630         struct dquot *dquot, *old_dquot = NULL;
631         int ret = 0;
632
633         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
634
635         spin_lock(&dq_list_lock);
636         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
637                 if (!dquot_active(dquot))
638                         continue;
639                 if (dquot->dq_sb != sb)
640                         continue;
641                 /* Now we have active dquot so we can just increase use count */
642                 atomic_inc(&dquot->dq_count);
643                 spin_unlock(&dq_list_lock);
644                 dqput(old_dquot);
645                 old_dquot = dquot;
646                 /*
647                  * ->release_dquot() can be racing with us. Our reference
648                  * protects us from new calls to it so just wait for any
649                  * outstanding call and recheck the DQ_ACTIVE_B after that.
650                  */
651                 wait_on_dquot(dquot);
652                 if (dquot_active(dquot)) {
653                         ret = fn(dquot, priv);
654                         if (ret < 0)
655                                 goto out;
656                 }
657                 spin_lock(&dq_list_lock);
658                 /* We are safe to continue now because our dquot could not
659                  * be moved out of the inuse list while we hold the reference */
660         }
661         spin_unlock(&dq_list_lock);
662 out:
663         dqput(old_dquot);
664         return ret;
665 }
666 EXPORT_SYMBOL(dquot_scan_active);
667
668 static inline int dquot_write_dquot(struct dquot *dquot)
669 {
670         int ret = dquot->dq_sb->dq_op->write_dquot(dquot);
671         if (ret < 0) {
672                 quota_error(dquot->dq_sb, "Can't write quota structure "
673                             "(error %d). Quota may get out of sync!", ret);
674                 /* Clear dirty bit anyway to avoid infinite loop. */
675                 clear_dquot_dirty(dquot);
676         }
677         return ret;
678 }
679
680 /* Write all dquot structures to quota files */
681 int dquot_writeback_dquots(struct super_block *sb, int type)
682 {
683         struct list_head dirty;
684         struct dquot *dquot;
685         struct quota_info *dqopt = sb_dqopt(sb);
686         int cnt;
687         int err, ret = 0;
688
689         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
690
691         flush_delayed_work(&quota_release_work);
692
693         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
694                 if (type != -1 && cnt != type)
695                         continue;
696                 if (!sb_has_quota_active(sb, cnt))
697                         continue;
698                 spin_lock(&dq_list_lock);
699                 /* Move list away to avoid livelock. */
700                 list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty);
701                 while (!list_empty(&dirty)) {
702                         dquot = list_first_entry(&dirty, struct dquot,
703                                                  dq_dirty);
704
705                         WARN_ON(!dquot_active(dquot));
706                         /* If the dquot is releasing we should not touch it */
707                         if (test_bit(DQ_RELEASING_B, &dquot->dq_flags)) {
708                                 spin_unlock(&dq_list_lock);
709                                 flush_delayed_work(&quota_release_work);
710                                 spin_lock(&dq_list_lock);
711                                 continue;
712                         }
713
714                         /* Now we have active dquot from which someone is
715                          * holding reference so we can safely just increase
716                          * use count */
717                         dqgrab(dquot);
718                         spin_unlock(&dq_list_lock);
719                         err = dquot_write_dquot(dquot);
720                         if (err && !ret)
721                                 ret = err;
722                         dqput(dquot);
723                         spin_lock(&dq_list_lock);
724                 }
725                 spin_unlock(&dq_list_lock);
726         }
727
728         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
729                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
730                     && info_dirty(&dqopt->info[cnt]))
731                         sb->dq_op->write_info(sb, cnt);
732         dqstats_inc(DQST_SYNCS);
733
734         return ret;
735 }
736 EXPORT_SYMBOL(dquot_writeback_dquots);
737
738 /* Write all dquot structures to disk and make them visible from userspace */
739 int dquot_quota_sync(struct super_block *sb, int type)
740 {
741         struct quota_info *dqopt = sb_dqopt(sb);
742         int cnt;
743         int ret;
744
745         ret = dquot_writeback_dquots(sb, type);
746         if (ret)
747                 return ret;
748         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
749                 return 0;
750
751         /* This is not very clever (and fast) but currently I don't know about
752          * any other simple way of getting quota data to disk and we must get
753          * them there for userspace to be visible... */
754         if (sb->s_op->sync_fs) {
755                 ret = sb->s_op->sync_fs(sb, 1);
756                 if (ret)
757                         return ret;
758         }
759         ret = sync_blockdev(sb->s_bdev);
760         if (ret)
761                 return ret;
762
763         /*
764          * Now when everything is written we can discard the pagecache so
765          * that userspace sees the changes.
766          */
767         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
768                 if (type != -1 && cnt != type)
769                         continue;
770                 if (!sb_has_quota_active(sb, cnt))
771                         continue;
772                 inode_lock(dqopt->files[cnt]);
773                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
774                 inode_unlock(dqopt->files[cnt]);
775         }
776
777         return 0;
778 }
779 EXPORT_SYMBOL(dquot_quota_sync);
780
781 static unsigned long
782 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
783 {
784         struct dquot *dquot;
785         unsigned long freed = 0;
786
787         spin_lock(&dq_list_lock);
788         while (!list_empty(&free_dquots) && sc->nr_to_scan) {
789                 dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
790                 remove_dquot_hash(dquot);
791                 remove_free_dquot(dquot);
792                 remove_inuse(dquot);
793                 do_destroy_dquot(dquot);
794                 sc->nr_to_scan--;
795                 freed++;
796         }
797         spin_unlock(&dq_list_lock);
798         return freed;
799 }
800
801 static unsigned long
802 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
803 {
804         return vfs_pressure_ratio(
805         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
806 }
807
808 /*
809  * Safely release dquot and put reference to dquot.
810  */
811 static void quota_release_workfn(struct work_struct *work)
812 {
813         struct dquot *dquot;
814         struct list_head rls_head;
815
816         spin_lock(&dq_list_lock);
817         /* Exchange the list head to avoid livelock. */
818         list_replace_init(&releasing_dquots, &rls_head);
819         spin_unlock(&dq_list_lock);
820         synchronize_srcu(&dquot_srcu);
821
822 restart:
823         spin_lock(&dq_list_lock);
824         while (!list_empty(&rls_head)) {
825                 dquot = list_first_entry(&rls_head, struct dquot, dq_free);
826                 WARN_ON_ONCE(atomic_read(&dquot->dq_count));
827                 /*
828                  * Note that DQ_RELEASING_B protects us from racing with
829                  * invalidate_dquots() calls so we are safe to work with the
830                  * dquot even after we drop dq_list_lock.
831                  */
832                 if (dquot_dirty(dquot)) {
833                         spin_unlock(&dq_list_lock);
834                         /* Commit dquot before releasing */
835                         dquot_write_dquot(dquot);
836                         goto restart;
837                 }
838                 if (dquot_active(dquot)) {
839                         spin_unlock(&dq_list_lock);
840                         dquot->dq_sb->dq_op->release_dquot(dquot);
841                         goto restart;
842                 }
843                 /* Dquot is inactive and clean, now move it to free list */
844                 remove_free_dquot(dquot);
845                 put_dquot_last(dquot);
846         }
847         spin_unlock(&dq_list_lock);
848 }
849
850 /*
851  * Put reference to dquot
852  */
853 void dqput(struct dquot *dquot)
854 {
855         if (!dquot)
856                 return;
857 #ifdef CONFIG_QUOTA_DEBUG
858         if (!atomic_read(&dquot->dq_count)) {
859                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
860                             quotatypes[dquot->dq_id.type],
861                             from_kqid(&init_user_ns, dquot->dq_id));
862                 BUG();
863         }
864 #endif
865         dqstats_inc(DQST_DROPS);
866
867         spin_lock(&dq_list_lock);
868         if (atomic_read(&dquot->dq_count) > 1) {
869                 /* We have more than one user... nothing to do */
870                 atomic_dec(&dquot->dq_count);
871                 /* Releasing dquot during quotaoff phase? */
872                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
873                     atomic_read(&dquot->dq_count) == 1)
874                         wake_up(&dquot_ref_wq);
875                 spin_unlock(&dq_list_lock);
876                 return;
877         }
878
879         /* Need to release dquot? */
880         WARN_ON_ONCE(!list_empty(&dquot->dq_free));
881         put_releasing_dquots(dquot);
882         atomic_dec(&dquot->dq_count);
883         spin_unlock(&dq_list_lock);
884         queue_delayed_work(system_unbound_wq, &quota_release_work, 1);
885 }
886 EXPORT_SYMBOL(dqput);
887
888 struct dquot *dquot_alloc(struct super_block *sb, int type)
889 {
890         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
891 }
892 EXPORT_SYMBOL(dquot_alloc);
893
894 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
895 {
896         struct dquot *dquot;
897
898         dquot = sb->dq_op->alloc_dquot(sb, type);
899         if(!dquot)
900                 return NULL;
901
902         mutex_init(&dquot->dq_lock);
903         INIT_LIST_HEAD(&dquot->dq_free);
904         INIT_LIST_HEAD(&dquot->dq_inuse);
905         INIT_HLIST_NODE(&dquot->dq_hash);
906         INIT_LIST_HEAD(&dquot->dq_dirty);
907         dquot->dq_sb = sb;
908         dquot->dq_id = make_kqid_invalid(type);
909         atomic_set(&dquot->dq_count, 1);
910         spin_lock_init(&dquot->dq_dqb_lock);
911
912         return dquot;
913 }
914
915 /*
916  * Get reference to dquot
917  *
918  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
919  * destroying our dquot by:
920  *   a) checking for quota flags under dq_list_lock and
921  *   b) getting a reference to dquot before we release dq_list_lock
922  */
923 struct dquot *dqget(struct super_block *sb, struct kqid qid)
924 {
925         unsigned int hashent = hashfn(sb, qid);
926         struct dquot *dquot, *empty = NULL;
927
928         if (!qid_has_mapping(sb->s_user_ns, qid))
929                 return ERR_PTR(-EINVAL);
930
931         if (!sb_has_quota_active(sb, qid.type))
932                 return ERR_PTR(-ESRCH);
933 we_slept:
934         spin_lock(&dq_list_lock);
935         spin_lock(&dq_state_lock);
936         if (!sb_has_quota_active(sb, qid.type)) {
937                 spin_unlock(&dq_state_lock);
938                 spin_unlock(&dq_list_lock);
939                 dquot = ERR_PTR(-ESRCH);
940                 goto out;
941         }
942         spin_unlock(&dq_state_lock);
943
944         dquot = find_dquot(hashent, sb, qid);
945         if (!dquot) {
946                 if (!empty) {
947                         spin_unlock(&dq_list_lock);
948                         empty = get_empty_dquot(sb, qid.type);
949                         if (!empty)
950                                 schedule();     /* Try to wait for a moment... */
951                         goto we_slept;
952                 }
953                 dquot = empty;
954                 empty = NULL;
955                 dquot->dq_id = qid;
956                 /* all dquots go on the inuse_list */
957                 put_inuse(dquot);
958                 /* hash it first so it can be found */
959                 insert_dquot_hash(dquot);
960                 spin_unlock(&dq_list_lock);
961                 dqstats_inc(DQST_LOOKUPS);
962         } else {
963                 if (!atomic_read(&dquot->dq_count))
964                         remove_free_dquot(dquot);
965                 atomic_inc(&dquot->dq_count);
966                 spin_unlock(&dq_list_lock);
967                 dqstats_inc(DQST_CACHE_HITS);
968                 dqstats_inc(DQST_LOOKUPS);
969         }
970         /* Wait for dq_lock - after this we know that either dquot_release() is
971          * already finished or it will be canceled due to dq_count > 0 test */
972         wait_on_dquot(dquot);
973         /* Read the dquot / allocate space in quota file */
974         if (!dquot_active(dquot)) {
975                 int err;
976
977                 err = sb->dq_op->acquire_dquot(dquot);
978                 if (err < 0) {
979                         dqput(dquot);
980                         dquot = ERR_PTR(err);
981                         goto out;
982                 }
983         }
984         /*
985          * Make sure following reads see filled structure - paired with
986          * smp_mb__before_atomic() in dquot_acquire().
987          */
988         smp_rmb();
989         /* Has somebody invalidated entry under us? */
990         WARN_ON_ONCE(hlist_unhashed(&dquot->dq_hash));
991 out:
992         if (empty)
993                 do_destroy_dquot(empty);
994
995         return dquot;
996 }
997 EXPORT_SYMBOL(dqget);
998
999 static inline struct dquot __rcu **i_dquot(struct inode *inode)
1000 {
1001         return inode->i_sb->s_op->get_dquots(inode);
1002 }
1003
1004 static int dqinit_needed(struct inode *inode, int type)
1005 {
1006         struct dquot __rcu * const *dquots;
1007         int cnt;
1008
1009         if (IS_NOQUOTA(inode))
1010                 return 0;
1011
1012         dquots = i_dquot(inode);
1013         if (type != -1)
1014                 return !dquots[type];
1015         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1016                 if (!dquots[cnt])
1017                         return 1;
1018         return 0;
1019 }
1020
1021 /* This routine is guarded by s_umount semaphore */
1022 static int add_dquot_ref(struct super_block *sb, int type)
1023 {
1024         struct inode *inode, *old_inode = NULL;
1025 #ifdef CONFIG_QUOTA_DEBUG
1026         int reserved = 0;
1027 #endif
1028         int err = 0;
1029
1030         spin_lock(&sb->s_inode_list_lock);
1031         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1032                 spin_lock(&inode->i_lock);
1033                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
1034                     !atomic_read(&inode->i_writecount) ||
1035                     !dqinit_needed(inode, type)) {
1036                         spin_unlock(&inode->i_lock);
1037                         continue;
1038                 }
1039                 __iget(inode);
1040                 spin_unlock(&inode->i_lock);
1041                 spin_unlock(&sb->s_inode_list_lock);
1042
1043 #ifdef CONFIG_QUOTA_DEBUG
1044                 if (unlikely(inode_get_rsv_space(inode) > 0))
1045                         reserved = 1;
1046 #endif
1047                 iput(old_inode);
1048                 err = __dquot_initialize(inode, type);
1049                 if (err) {
1050                         iput(inode);
1051                         goto out;
1052                 }
1053
1054                 /*
1055                  * We hold a reference to 'inode' so it couldn't have been
1056                  * removed from s_inodes list while we dropped the
1057                  * s_inode_list_lock. We cannot iput the inode now as we can be
1058                  * holding the last reference and we cannot iput it under
1059                  * s_inode_list_lock. So we keep the reference and iput it
1060                  * later.
1061                  */
1062                 old_inode = inode;
1063                 cond_resched();
1064                 spin_lock(&sb->s_inode_list_lock);
1065         }
1066         spin_unlock(&sb->s_inode_list_lock);
1067         iput(old_inode);
1068 out:
1069 #ifdef CONFIG_QUOTA_DEBUG
1070         if (reserved) {
1071                 quota_error(sb, "Writes happened before quota was turned on "
1072                         "thus quota information is probably inconsistent. "
1073                         "Please run quotacheck(8)");
1074         }
1075 #endif
1076         return err;
1077 }
1078
1079 static void remove_dquot_ref(struct super_block *sb, int type)
1080 {
1081         struct inode *inode;
1082 #ifdef CONFIG_QUOTA_DEBUG
1083         int reserved = 0;
1084 #endif
1085
1086         spin_lock(&sb->s_inode_list_lock);
1087         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1088                 /*
1089                  *  We have to scan also I_NEW inodes because they can already
1090                  *  have quota pointer initialized. Luckily, we need to touch
1091                  *  only quota pointers and these have separate locking
1092                  *  (dq_data_lock).
1093                  */
1094                 spin_lock(&dq_data_lock);
1095                 if (!IS_NOQUOTA(inode)) {
1096                         struct dquot __rcu **dquots = i_dquot(inode);
1097                         struct dquot *dquot = srcu_dereference_check(
1098                                 dquots[type], &dquot_srcu,
1099                                 lockdep_is_held(&dq_data_lock));
1100
1101 #ifdef CONFIG_QUOTA_DEBUG
1102                         if (unlikely(inode_get_rsv_space(inode) > 0))
1103                                 reserved = 1;
1104 #endif
1105                         rcu_assign_pointer(dquots[type], NULL);
1106                         if (dquot)
1107                                 dqput(dquot);
1108                 }
1109                 spin_unlock(&dq_data_lock);
1110         }
1111         spin_unlock(&sb->s_inode_list_lock);
1112 #ifdef CONFIG_QUOTA_DEBUG
1113         if (reserved) {
1114                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1115                         " was disabled thus quota information is probably "
1116                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1117         }
1118 #endif
1119 }
1120
1121 /* Gather all references from inodes and drop them */
1122 static void drop_dquot_ref(struct super_block *sb, int type)
1123 {
1124         if (sb->dq_op)
1125                 remove_dquot_ref(sb, type);
1126 }
1127
1128 static inline
1129 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1130 {
1131         if (dquot->dq_dqb.dqb_rsvspace >= number)
1132                 dquot->dq_dqb.dqb_rsvspace -= number;
1133         else {
1134                 WARN_ON_ONCE(1);
1135                 dquot->dq_dqb.dqb_rsvspace = 0;
1136         }
1137         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1138             dquot->dq_dqb.dqb_bsoftlimit)
1139                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1140         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1141 }
1142
1143 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1144 {
1145         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1146             dquot->dq_dqb.dqb_curinodes >= number)
1147                 dquot->dq_dqb.dqb_curinodes -= number;
1148         else
1149                 dquot->dq_dqb.dqb_curinodes = 0;
1150         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1151                 dquot->dq_dqb.dqb_itime = (time64_t) 0;
1152         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1153 }
1154
1155 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1156 {
1157         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1158             dquot->dq_dqb.dqb_curspace >= number)
1159                 dquot->dq_dqb.dqb_curspace -= number;
1160         else
1161                 dquot->dq_dqb.dqb_curspace = 0;
1162         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1163             dquot->dq_dqb.dqb_bsoftlimit)
1164                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1165         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1166 }
1167
1168 struct dquot_warn {
1169         struct super_block *w_sb;
1170         struct kqid w_dq_id;
1171         short w_type;
1172 };
1173
1174 static int warning_issued(struct dquot *dquot, const int warntype)
1175 {
1176         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1177                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1178                 ((warntype == QUOTA_NL_IHARDWARN ||
1179                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1180
1181         if (!flag)
1182                 return 0;
1183         return test_and_set_bit(flag, &dquot->dq_flags);
1184 }
1185
1186 #ifdef CONFIG_PRINT_QUOTA_WARNING
1187 static int flag_print_warnings = 1;
1188
1189 static int need_print_warning(struct dquot_warn *warn)
1190 {
1191         if (!flag_print_warnings)
1192                 return 0;
1193
1194         switch (warn->w_dq_id.type) {
1195                 case USRQUOTA:
1196                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1197                 case GRPQUOTA:
1198                         return in_group_p(warn->w_dq_id.gid);
1199                 case PRJQUOTA:
1200                         return 1;
1201         }
1202         return 0;
1203 }
1204
1205 /* Print warning to user which exceeded quota */
1206 static void print_warning(struct dquot_warn *warn)
1207 {
1208         char *msg = NULL;
1209         struct tty_struct *tty;
1210         int warntype = warn->w_type;
1211
1212         if (warntype == QUOTA_NL_IHARDBELOW ||
1213             warntype == QUOTA_NL_ISOFTBELOW ||
1214             warntype == QUOTA_NL_BHARDBELOW ||
1215             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1216                 return;
1217
1218         tty = get_current_tty();
1219         if (!tty)
1220                 return;
1221         tty_write_message(tty, warn->w_sb->s_id);
1222         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1223                 tty_write_message(tty, ": warning, ");
1224         else
1225                 tty_write_message(tty, ": write failed, ");
1226         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1227         switch (warntype) {
1228                 case QUOTA_NL_IHARDWARN:
1229                         msg = " file limit reached.\r\n";
1230                         break;
1231                 case QUOTA_NL_ISOFTLONGWARN:
1232                         msg = " file quota exceeded too long.\r\n";
1233                         break;
1234                 case QUOTA_NL_ISOFTWARN:
1235                         msg = " file quota exceeded.\r\n";
1236                         break;
1237                 case QUOTA_NL_BHARDWARN:
1238                         msg = " block limit reached.\r\n";
1239                         break;
1240                 case QUOTA_NL_BSOFTLONGWARN:
1241                         msg = " block quota exceeded too long.\r\n";
1242                         break;
1243                 case QUOTA_NL_BSOFTWARN:
1244                         msg = " block quota exceeded.\r\n";
1245                         break;
1246         }
1247         tty_write_message(tty, msg);
1248         tty_kref_put(tty);
1249 }
1250 #endif
1251
1252 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1253                             int warntype)
1254 {
1255         if (warning_issued(dquot, warntype))
1256                 return;
1257         warn->w_type = warntype;
1258         warn->w_sb = dquot->dq_sb;
1259         warn->w_dq_id = dquot->dq_id;
1260 }
1261
1262 /*
1263  * Write warnings to the console and send warning messages over netlink.
1264  *
1265  * Note that this function can call into tty and networking code.
1266  */
1267 static void flush_warnings(struct dquot_warn *warn)
1268 {
1269         int i;
1270
1271         for (i = 0; i < MAXQUOTAS; i++) {
1272                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1273                         continue;
1274 #ifdef CONFIG_PRINT_QUOTA_WARNING
1275                 print_warning(&warn[i]);
1276 #endif
1277                 quota_send_warning(warn[i].w_dq_id,
1278                                    warn[i].w_sb->s_dev, warn[i].w_type);
1279         }
1280 }
1281
1282 static int ignore_hardlimit(struct dquot *dquot)
1283 {
1284         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1285
1286         return capable(CAP_SYS_RESOURCE) &&
1287                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1288                 !(info->dqi_flags & DQF_ROOT_SQUASH));
1289 }
1290
1291 static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
1292                             struct dquot_warn *warn)
1293 {
1294         qsize_t newinodes;
1295         int ret = 0;
1296
1297         spin_lock(&dquot->dq_dqb_lock);
1298         newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1299         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1300             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1301                 goto add;
1302
1303         if (dquot->dq_dqb.dqb_ihardlimit &&
1304             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1305             !ignore_hardlimit(dquot)) {
1306                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1307                 ret = -EDQUOT;
1308                 goto out;
1309         }
1310
1311         if (dquot->dq_dqb.dqb_isoftlimit &&
1312             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1313             dquot->dq_dqb.dqb_itime &&
1314             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
1315             !ignore_hardlimit(dquot)) {
1316                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1317                 ret = -EDQUOT;
1318                 goto out;
1319         }
1320
1321         if (dquot->dq_dqb.dqb_isoftlimit &&
1322             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1323             dquot->dq_dqb.dqb_itime == 0) {
1324                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
1325                 dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
1326                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
1327         }
1328 add:
1329         dquot->dq_dqb.dqb_curinodes = newinodes;
1330
1331 out:
1332         spin_unlock(&dquot->dq_dqb_lock);
1333         return ret;
1334 }
1335
1336 static int dquot_add_space(struct dquot *dquot, qsize_t space,
1337                            qsize_t rsv_space, unsigned int flags,
1338                            struct dquot_warn *warn)
1339 {
1340         qsize_t tspace;
1341         struct super_block *sb = dquot->dq_sb;
1342         int ret = 0;
1343
1344         spin_lock(&dquot->dq_dqb_lock);
1345         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1346             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1347                 goto finish;
1348
1349         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1350                 + space + rsv_space;
1351
1352         if (dquot->dq_dqb.dqb_bhardlimit &&
1353             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1354             !ignore_hardlimit(dquot)) {
1355                 if (flags & DQUOT_SPACE_WARN)
1356                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1357                 ret = -EDQUOT;
1358                 goto finish;
1359         }
1360
1361         if (dquot->dq_dqb.dqb_bsoftlimit &&
1362             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1363             dquot->dq_dqb.dqb_btime &&
1364             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
1365             !ignore_hardlimit(dquot)) {
1366                 if (flags & DQUOT_SPACE_WARN)
1367                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1368                 ret = -EDQUOT;
1369                 goto finish;
1370         }
1371
1372         if (dquot->dq_dqb.dqb_bsoftlimit &&
1373             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1374             dquot->dq_dqb.dqb_btime == 0) {
1375                 if (flags & DQUOT_SPACE_WARN) {
1376                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1377                         dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
1378                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1379                 } else {
1380                         /*
1381                          * We don't allow preallocation to exceed softlimit so exceeding will
1382                          * be always printed
1383                          */
1384                         ret = -EDQUOT;
1385                         goto finish;
1386                 }
1387         }
1388 finish:
1389         /*
1390          * We have to be careful and go through warning generation & grace time
1391          * setting even if DQUOT_SPACE_NOFAIL is set. That's why we check it
1392          * only here...
1393          */
1394         if (flags & DQUOT_SPACE_NOFAIL)
1395                 ret = 0;
1396         if (!ret) {
1397                 dquot->dq_dqb.dqb_rsvspace += rsv_space;
1398                 dquot->dq_dqb.dqb_curspace += space;
1399         }
1400         spin_unlock(&dquot->dq_dqb_lock);
1401         return ret;
1402 }
1403
1404 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1405 {
1406         qsize_t newinodes;
1407
1408         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1409             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1410             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1411                 return QUOTA_NL_NOWARN;
1412
1413         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1414         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1415                 return QUOTA_NL_ISOFTBELOW;
1416         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1417             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1418                 return QUOTA_NL_IHARDBELOW;
1419         return QUOTA_NL_NOWARN;
1420 }
1421
1422 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1423 {
1424         qsize_t tspace;
1425
1426         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace;
1427
1428         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1429             tspace <= dquot->dq_dqb.dqb_bsoftlimit)
1430                 return QUOTA_NL_NOWARN;
1431
1432         if (tspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1433                 return QUOTA_NL_BSOFTBELOW;
1434         if (tspace >= dquot->dq_dqb.dqb_bhardlimit &&
1435             tspace - space < dquot->dq_dqb.dqb_bhardlimit)
1436                 return QUOTA_NL_BHARDBELOW;
1437         return QUOTA_NL_NOWARN;
1438 }
1439
1440 static int inode_quota_active(const struct inode *inode)
1441 {
1442         struct super_block *sb = inode->i_sb;
1443
1444         if (IS_NOQUOTA(inode))
1445                 return 0;
1446         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1447 }
1448
1449 /*
1450  * Initialize quota pointers in inode
1451  *
1452  * It is better to call this function outside of any transaction as it
1453  * might need a lot of space in journal for dquot structure allocation.
1454  */
1455 static int __dquot_initialize(struct inode *inode, int type)
1456 {
1457         int cnt, init_needed = 0;
1458         struct dquot __rcu **dquots;
1459         struct dquot *got[MAXQUOTAS] = {};
1460         struct super_block *sb = inode->i_sb;
1461         qsize_t rsv;
1462         int ret = 0;
1463
1464         if (!inode_quota_active(inode))
1465                 return 0;
1466
1467         dquots = i_dquot(inode);
1468
1469         /* First get references to structures we might need. */
1470         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1471                 struct kqid qid;
1472                 kprojid_t projid;
1473                 int rc;
1474                 struct dquot *dquot;
1475
1476                 if (type != -1 && cnt != type)
1477                         continue;
1478                 /*
1479                  * The i_dquot should have been initialized in most cases,
1480                  * we check it without locking here to avoid unnecessary
1481                  * dqget()/dqput() calls.
1482                  */
1483                 if (dquots[cnt])
1484                         continue;
1485
1486                 if (!sb_has_quota_active(sb, cnt))
1487                         continue;
1488
1489                 init_needed = 1;
1490
1491                 switch (cnt) {
1492                 case USRQUOTA:
1493                         qid = make_kqid_uid(inode->i_uid);
1494                         break;
1495                 case GRPQUOTA:
1496                         qid = make_kqid_gid(inode->i_gid);
1497                         break;
1498                 case PRJQUOTA:
1499                         rc = inode->i_sb->dq_op->get_projid(inode, &projid);
1500                         if (rc)
1501                                 continue;
1502                         qid = make_kqid_projid(projid);
1503                         break;
1504                 }
1505                 dquot = dqget(sb, qid);
1506                 if (IS_ERR(dquot)) {
1507                         /* We raced with somebody turning quotas off... */
1508                         if (PTR_ERR(dquot) != -ESRCH) {
1509                                 ret = PTR_ERR(dquot);
1510                                 goto out_put;
1511                         }
1512                         dquot = NULL;
1513                 }
1514                 got[cnt] = dquot;
1515         }
1516
1517         /* All required i_dquot has been initialized */
1518         if (!init_needed)
1519                 return 0;
1520
1521         spin_lock(&dq_data_lock);
1522         if (IS_NOQUOTA(inode))
1523                 goto out_lock;
1524         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1525                 if (type != -1 && cnt != type)
1526                         continue;
1527                 /* Avoid races with quotaoff() */
1528                 if (!sb_has_quota_active(sb, cnt))
1529                         continue;
1530                 /* We could race with quotaon or dqget() could have failed */
1531                 if (!got[cnt])
1532                         continue;
1533                 if (!dquots[cnt]) {
1534                         rcu_assign_pointer(dquots[cnt], got[cnt]);
1535                         got[cnt] = NULL;
1536                         /*
1537                          * Make quota reservation system happy if someone
1538                          * did a write before quota was turned on
1539                          */
1540                         rsv = inode_get_rsv_space(inode);
1541                         if (unlikely(rsv)) {
1542                                 struct dquot *dquot = srcu_dereference_check(
1543                                         dquots[cnt], &dquot_srcu,
1544                                         lockdep_is_held(&dq_data_lock));
1545
1546                                 spin_lock(&inode->i_lock);
1547                                 /* Get reservation again under proper lock */
1548                                 rsv = __inode_get_rsv_space(inode);
1549                                 spin_lock(&dquot->dq_dqb_lock);
1550                                 dquot->dq_dqb.dqb_rsvspace += rsv;
1551                                 spin_unlock(&dquot->dq_dqb_lock);
1552                                 spin_unlock(&inode->i_lock);
1553                         }
1554                 }
1555         }
1556 out_lock:
1557         spin_unlock(&dq_data_lock);
1558 out_put:
1559         /* Drop unused references */
1560         dqput_all(got);
1561
1562         return ret;
1563 }
1564
1565 int dquot_initialize(struct inode *inode)
1566 {
1567         return __dquot_initialize(inode, -1);
1568 }
1569 EXPORT_SYMBOL(dquot_initialize);
1570
1571 bool dquot_initialize_needed(struct inode *inode)
1572 {
1573         struct dquot __rcu **dquots;
1574         int i;
1575
1576         if (!inode_quota_active(inode))
1577                 return false;
1578
1579         dquots = i_dquot(inode);
1580         for (i = 0; i < MAXQUOTAS; i++)
1581                 if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
1582                         return true;
1583         return false;
1584 }
1585 EXPORT_SYMBOL(dquot_initialize_needed);
1586
1587 /*
1588  * Release all quotas referenced by inode.
1589  *
1590  * This function only be called on inode free or converting
1591  * a file to quota file, no other users for the i_dquot in
1592  * both cases, so we needn't call synchronize_srcu() after
1593  * clearing i_dquot.
1594  */
1595 static void __dquot_drop(struct inode *inode)
1596 {
1597         int cnt;
1598         struct dquot __rcu **dquots = i_dquot(inode);
1599         struct dquot *put[MAXQUOTAS];
1600
1601         spin_lock(&dq_data_lock);
1602         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1603                 put[cnt] = srcu_dereference_check(dquots[cnt], &dquot_srcu,
1604                                         lockdep_is_held(&dq_data_lock));
1605                 rcu_assign_pointer(dquots[cnt], NULL);
1606         }
1607         spin_unlock(&dq_data_lock);
1608         dqput_all(put);
1609 }
1610
1611 void dquot_drop(struct inode *inode)
1612 {
1613         struct dquot __rcu * const *dquots;
1614         int cnt;
1615
1616         if (IS_NOQUOTA(inode))
1617                 return;
1618
1619         /*
1620          * Test before calling to rule out calls from proc and such
1621          * where we are not allowed to block. Note that this is
1622          * actually reliable test even without the lock - the caller
1623          * must assure that nobody can come after the DQUOT_DROP and
1624          * add quota pointers back anyway.
1625          */
1626         dquots = i_dquot(inode);
1627         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1628                 if (dquots[cnt])
1629                         break;
1630         }
1631
1632         if (cnt < MAXQUOTAS)
1633                 __dquot_drop(inode);
1634 }
1635 EXPORT_SYMBOL(dquot_drop);
1636
1637 /*
1638  * inode_reserved_space is managed internally by quota, and protected by
1639  * i_lock similar to i_blocks+i_bytes.
1640  */
1641 static qsize_t *inode_reserved_space(struct inode * inode)
1642 {
1643         /* Filesystem must explicitly define it's own method in order to use
1644          * quota reservation interface */
1645         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1646         return inode->i_sb->dq_op->get_reserved_space(inode);
1647 }
1648
1649 static qsize_t __inode_get_rsv_space(struct inode *inode)
1650 {
1651         if (!inode->i_sb->dq_op->get_reserved_space)
1652                 return 0;
1653         return *inode_reserved_space(inode);
1654 }
1655
1656 static qsize_t inode_get_rsv_space(struct inode *inode)
1657 {
1658         qsize_t ret;
1659
1660         if (!inode->i_sb->dq_op->get_reserved_space)
1661                 return 0;
1662         spin_lock(&inode->i_lock);
1663         ret = __inode_get_rsv_space(inode);
1664         spin_unlock(&inode->i_lock);
1665         return ret;
1666 }
1667
1668 /*
1669  * This functions updates i_blocks+i_bytes fields and quota information
1670  * (together with appropriate checks).
1671  *
1672  * NOTE: We absolutely rely on the fact that caller dirties the inode
1673  * (usually helpers in quotaops.h care about this) and holds a handle for
1674  * the current transaction so that dquot write and inode write go into the
1675  * same transaction.
1676  */
1677
1678 /*
1679  * This operation can block, but only after everything is updated
1680  */
1681 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1682 {
1683         int cnt, ret = 0, index;
1684         struct dquot_warn warn[MAXQUOTAS];
1685         int reserve = flags & DQUOT_SPACE_RESERVE;
1686         struct dquot __rcu **dquots;
1687         struct dquot *dquot;
1688
1689         if (!inode_quota_active(inode)) {
1690                 if (reserve) {
1691                         spin_lock(&inode->i_lock);
1692                         *inode_reserved_space(inode) += number;
1693                         spin_unlock(&inode->i_lock);
1694                 } else {
1695                         inode_add_bytes(inode, number);
1696                 }
1697                 goto out;
1698         }
1699
1700         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1701                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1702
1703         dquots = i_dquot(inode);
1704         index = srcu_read_lock(&dquot_srcu);
1705         spin_lock(&inode->i_lock);
1706         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1707                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1708                 if (!dquot)
1709                         continue;
1710                 if (reserve) {
1711                         ret = dquot_add_space(dquot, 0, number, flags, &warn[cnt]);
1712                 } else {
1713                         ret = dquot_add_space(dquot, number, 0, flags, &warn[cnt]);
1714                 }
1715                 if (ret) {
1716                         /* Back out changes we already did */
1717                         for (cnt--; cnt >= 0; cnt--) {
1718                                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1719                                 if (!dquot)
1720                                         continue;
1721                                 spin_lock(&dquot->dq_dqb_lock);
1722                                 if (reserve)
1723                                         dquot_free_reserved_space(dquot, number);
1724                                 else
1725                                         dquot_decr_space(dquot, number);
1726                                 spin_unlock(&dquot->dq_dqb_lock);
1727                         }
1728                         spin_unlock(&inode->i_lock);
1729                         goto out_flush_warn;
1730                 }
1731         }
1732         if (reserve)
1733                 *inode_reserved_space(inode) += number;
1734         else
1735                 __inode_add_bytes(inode, number);
1736         spin_unlock(&inode->i_lock);
1737
1738         if (reserve)
1739                 goto out_flush_warn;
1740         ret = mark_all_dquot_dirty(dquots);
1741 out_flush_warn:
1742         srcu_read_unlock(&dquot_srcu, index);
1743         flush_warnings(warn);
1744 out:
1745         return ret;
1746 }
1747 EXPORT_SYMBOL(__dquot_alloc_space);
1748
1749 /*
1750  * This operation can block, but only after everything is updated
1751  */
1752 int dquot_alloc_inode(struct inode *inode)
1753 {
1754         int cnt, ret = 0, index;
1755         struct dquot_warn warn[MAXQUOTAS];
1756         struct dquot __rcu * const *dquots;
1757         struct dquot *dquot;
1758
1759         if (!inode_quota_active(inode))
1760                 return 0;
1761         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1762                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1763
1764         dquots = i_dquot(inode);
1765         index = srcu_read_lock(&dquot_srcu);
1766         spin_lock(&inode->i_lock);
1767         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1768                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1769                 if (!dquot)
1770                         continue;
1771                 ret = dquot_add_inodes(dquot, 1, &warn[cnt]);
1772                 if (ret) {
1773                         for (cnt--; cnt >= 0; cnt--) {
1774                                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1775                                 if (!dquot)
1776                                         continue;
1777                                 /* Back out changes we already did */
1778                                 spin_lock(&dquot->dq_dqb_lock);
1779                                 dquot_decr_inodes(dquot, 1);
1780                                 spin_unlock(&dquot->dq_dqb_lock);
1781                         }
1782                         goto warn_put_all;
1783                 }
1784         }
1785
1786 warn_put_all:
1787         spin_unlock(&inode->i_lock);
1788         if (ret == 0)
1789                 ret = mark_all_dquot_dirty(dquots);
1790         srcu_read_unlock(&dquot_srcu, index);
1791         flush_warnings(warn);
1792         return ret;
1793 }
1794 EXPORT_SYMBOL(dquot_alloc_inode);
1795
1796 /*
1797  * Convert in-memory reserved quotas to real consumed quotas
1798  */
1799 void dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1800 {
1801         struct dquot __rcu **dquots;
1802         struct dquot *dquot;
1803         int cnt, index;
1804
1805         if (!inode_quota_active(inode)) {
1806                 spin_lock(&inode->i_lock);
1807                 *inode_reserved_space(inode) -= number;
1808                 __inode_add_bytes(inode, number);
1809                 spin_unlock(&inode->i_lock);
1810                 return;
1811         }
1812
1813         dquots = i_dquot(inode);
1814         index = srcu_read_lock(&dquot_srcu);
1815         spin_lock(&inode->i_lock);
1816         /* Claim reserved quotas to allocated quotas */
1817         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1818                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1819                 if (dquot) {
1820                         spin_lock(&dquot->dq_dqb_lock);
1821                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
1822                                 number = dquot->dq_dqb.dqb_rsvspace;
1823                         dquot->dq_dqb.dqb_curspace += number;
1824                         dquot->dq_dqb.dqb_rsvspace -= number;
1825                         spin_unlock(&dquot->dq_dqb_lock);
1826                 }
1827         }
1828         /* Update inode bytes */
1829         *inode_reserved_space(inode) -= number;
1830         __inode_add_bytes(inode, number);
1831         spin_unlock(&inode->i_lock);
1832         mark_all_dquot_dirty(dquots);
1833         srcu_read_unlock(&dquot_srcu, index);
1834 }
1835 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1836
1837 /*
1838  * Convert allocated space back to in-memory reserved quotas
1839  */
1840 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1841 {
1842         struct dquot __rcu **dquots;
1843         struct dquot *dquot;
1844         int cnt, index;
1845
1846         if (!inode_quota_active(inode)) {
1847                 spin_lock(&inode->i_lock);
1848                 *inode_reserved_space(inode) += number;
1849                 __inode_sub_bytes(inode, number);
1850                 spin_unlock(&inode->i_lock);
1851                 return;
1852         }
1853
1854         dquots = i_dquot(inode);
1855         index = srcu_read_lock(&dquot_srcu);
1856         spin_lock(&inode->i_lock);
1857         /* Claim reserved quotas to allocated quotas */
1858         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1859                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1860                 if (dquot) {
1861                         spin_lock(&dquot->dq_dqb_lock);
1862                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1863                                 number = dquot->dq_dqb.dqb_curspace;
1864                         dquot->dq_dqb.dqb_rsvspace += number;
1865                         dquot->dq_dqb.dqb_curspace -= number;
1866                         spin_unlock(&dquot->dq_dqb_lock);
1867                 }
1868         }
1869         /* Update inode bytes */
1870         *inode_reserved_space(inode) += number;
1871         __inode_sub_bytes(inode, number);
1872         spin_unlock(&inode->i_lock);
1873         mark_all_dquot_dirty(dquots);
1874         srcu_read_unlock(&dquot_srcu, index);
1875 }
1876 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1877
1878 /*
1879  * This operation can block, but only after everything is updated
1880  */
1881 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1882 {
1883         unsigned int cnt;
1884         struct dquot_warn warn[MAXQUOTAS];
1885         struct dquot __rcu **dquots;
1886         struct dquot *dquot;
1887         int reserve = flags & DQUOT_SPACE_RESERVE, index;
1888
1889         if (!inode_quota_active(inode)) {
1890                 if (reserve) {
1891                         spin_lock(&inode->i_lock);
1892                         *inode_reserved_space(inode) -= number;
1893                         spin_unlock(&inode->i_lock);
1894                 } else {
1895                         inode_sub_bytes(inode, number);
1896                 }
1897                 return;
1898         }
1899
1900         dquots = i_dquot(inode);
1901         index = srcu_read_lock(&dquot_srcu);
1902         spin_lock(&inode->i_lock);
1903         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1904                 int wtype;
1905
1906                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1907                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1908                 if (!dquot)
1909                         continue;
1910                 spin_lock(&dquot->dq_dqb_lock);
1911                 wtype = info_bdq_free(dquot, number);
1912                 if (wtype != QUOTA_NL_NOWARN)
1913                         prepare_warning(&warn[cnt], dquot, wtype);
1914                 if (reserve)
1915                         dquot_free_reserved_space(dquot, number);
1916                 else
1917                         dquot_decr_space(dquot, number);
1918                 spin_unlock(&dquot->dq_dqb_lock);
1919         }
1920         if (reserve)
1921                 *inode_reserved_space(inode) -= number;
1922         else
1923                 __inode_sub_bytes(inode, number);
1924         spin_unlock(&inode->i_lock);
1925
1926         if (reserve)
1927                 goto out_unlock;
1928         mark_all_dquot_dirty(dquots);
1929 out_unlock:
1930         srcu_read_unlock(&dquot_srcu, index);
1931         flush_warnings(warn);
1932 }
1933 EXPORT_SYMBOL(__dquot_free_space);
1934
1935 /*
1936  * This operation can block, but only after everything is updated
1937  */
1938 void dquot_free_inode(struct inode *inode)
1939 {
1940         unsigned int cnt;
1941         struct dquot_warn warn[MAXQUOTAS];
1942         struct dquot __rcu * const *dquots;
1943         struct dquot *dquot;
1944         int index;
1945
1946         if (!inode_quota_active(inode))
1947                 return;
1948
1949         dquots = i_dquot(inode);
1950         index = srcu_read_lock(&dquot_srcu);
1951         spin_lock(&inode->i_lock);
1952         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1953                 int wtype;
1954                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1955                 dquot = srcu_dereference(dquots[cnt], &dquot_srcu);
1956                 if (!dquot)
1957                         continue;
1958                 spin_lock(&dquot->dq_dqb_lock);
1959                 wtype = info_idq_free(dquot, 1);
1960                 if (wtype != QUOTA_NL_NOWARN)
1961                         prepare_warning(&warn[cnt], dquot, wtype);
1962                 dquot_decr_inodes(dquot, 1);
1963                 spin_unlock(&dquot->dq_dqb_lock);
1964         }
1965         spin_unlock(&inode->i_lock);
1966         mark_all_dquot_dirty(dquots);
1967         srcu_read_unlock(&dquot_srcu, index);
1968         flush_warnings(warn);
1969 }
1970 EXPORT_SYMBOL(dquot_free_inode);
1971
1972 /*
1973  * Transfer the number of inode and blocks from one diskquota to an other.
1974  * On success, dquot references in transfer_to are consumed and references
1975  * to original dquots that need to be released are placed there. On failure,
1976  * references are kept untouched.
1977  *
1978  * This operation can block, but only after everything is updated
1979  * A transaction must be started when entering this function.
1980  *
1981  * We are holding reference on transfer_from & transfer_to, no need to
1982  * protect them by srcu_read_lock().
1983  */
1984 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1985 {
1986         qsize_t cur_space;
1987         qsize_t rsv_space = 0;
1988         qsize_t inode_usage = 1;
1989         struct dquot __rcu **dquots;
1990         struct dquot *transfer_from[MAXQUOTAS] = {};
1991         int cnt, index, ret = 0, err;
1992         char is_valid[MAXQUOTAS] = {};
1993         struct dquot_warn warn_to[MAXQUOTAS];
1994         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1995         struct dquot_warn warn_from_space[MAXQUOTAS];
1996
1997         if (IS_NOQUOTA(inode))
1998                 return 0;
1999
2000         if (inode->i_sb->dq_op->get_inode_usage) {
2001                 ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
2002                 if (ret)
2003                         return ret;
2004         }
2005
2006         /* Initialize the arrays */
2007         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2008                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
2009                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
2010                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
2011         }
2012
2013         spin_lock(&dq_data_lock);
2014         spin_lock(&inode->i_lock);
2015         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
2016                 spin_unlock(&inode->i_lock);
2017                 spin_unlock(&dq_data_lock);
2018                 return 0;
2019         }
2020         cur_space = __inode_get_bytes(inode);
2021         rsv_space = __inode_get_rsv_space(inode);
2022         dquots = i_dquot(inode);
2023         /*
2024          * Build the transfer_from list, check limits, and update usage in
2025          * the target structures.
2026          */
2027         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2028                 /*
2029                  * Skip changes for same uid or gid or for turned off quota-type.
2030                  */
2031                 if (!transfer_to[cnt])
2032                         continue;
2033                 /* Avoid races with quotaoff() */
2034                 if (!sb_has_quota_active(inode->i_sb, cnt))
2035                         continue;
2036                 is_valid[cnt] = 1;
2037                 transfer_from[cnt] = srcu_dereference_check(dquots[cnt],
2038                                 &dquot_srcu, lockdep_is_held(&dq_data_lock));
2039                 ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
2040                                        &warn_to[cnt]);
2041                 if (ret)
2042                         goto over_quota;
2043                 ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space,
2044                                       DQUOT_SPACE_WARN, &warn_to[cnt]);
2045                 if (ret) {
2046                         spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2047                         dquot_decr_inodes(transfer_to[cnt], inode_usage);
2048                         spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2049                         goto over_quota;
2050                 }
2051         }
2052
2053         /* Decrease usage for source structures and update quota pointers */
2054         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2055                 if (!is_valid[cnt])
2056                         continue;
2057                 /* Due to IO error we might not have transfer_from[] structure */
2058                 if (transfer_from[cnt]) {
2059                         int wtype;
2060
2061                         spin_lock(&transfer_from[cnt]->dq_dqb_lock);
2062                         wtype = info_idq_free(transfer_from[cnt], inode_usage);
2063                         if (wtype != QUOTA_NL_NOWARN)
2064                                 prepare_warning(&warn_from_inodes[cnt],
2065                                                 transfer_from[cnt], wtype);
2066                         wtype = info_bdq_free(transfer_from[cnt],
2067                                               cur_space + rsv_space);
2068                         if (wtype != QUOTA_NL_NOWARN)
2069                                 prepare_warning(&warn_from_space[cnt],
2070                                                 transfer_from[cnt], wtype);
2071                         dquot_decr_inodes(transfer_from[cnt], inode_usage);
2072                         dquot_decr_space(transfer_from[cnt], cur_space);
2073                         dquot_free_reserved_space(transfer_from[cnt],
2074                                                   rsv_space);
2075                         spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
2076                 }
2077                 rcu_assign_pointer(dquots[cnt], transfer_to[cnt]);
2078         }
2079         spin_unlock(&inode->i_lock);
2080         spin_unlock(&dq_data_lock);
2081
2082         /*
2083          * These arrays are local and we hold dquot references so we don't need
2084          * the srcu protection but still take dquot_srcu to avoid warning in
2085          * mark_all_dquot_dirty().
2086          */
2087         index = srcu_read_lock(&dquot_srcu);
2088         err = mark_all_dquot_dirty((struct dquot __rcu **)transfer_from);
2089         if (err < 0)
2090                 ret = err;
2091         err = mark_all_dquot_dirty((struct dquot __rcu **)transfer_to);
2092         if (err < 0)
2093                 ret = err;
2094         srcu_read_unlock(&dquot_srcu, index);
2095
2096         flush_warnings(warn_to);
2097         flush_warnings(warn_from_inodes);
2098         flush_warnings(warn_from_space);
2099         /* Pass back references to put */
2100         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2101                 if (is_valid[cnt])
2102                         transfer_to[cnt] = transfer_from[cnt];
2103         return ret;
2104 over_quota:
2105         /* Back out changes we already did */
2106         for (cnt--; cnt >= 0; cnt--) {
2107                 if (!is_valid[cnt])
2108                         continue;
2109                 spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2110                 dquot_decr_inodes(transfer_to[cnt], inode_usage);
2111                 dquot_decr_space(transfer_to[cnt], cur_space);
2112                 dquot_free_reserved_space(transfer_to[cnt], rsv_space);
2113                 spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2114         }
2115         spin_unlock(&inode->i_lock);
2116         spin_unlock(&dq_data_lock);
2117         flush_warnings(warn_to);
2118         return ret;
2119 }
2120 EXPORT_SYMBOL(__dquot_transfer);
2121
2122 /* Wrapper for transferring ownership of an inode for uid/gid only
2123  * Called from FSXXX_setattr()
2124  */
2125 int dquot_transfer(struct mnt_idmap *idmap, struct inode *inode,
2126                    struct iattr *iattr)
2127 {
2128         struct dquot *transfer_to[MAXQUOTAS] = {};
2129         struct dquot *dquot;
2130         struct super_block *sb = inode->i_sb;
2131         int ret;
2132
2133         if (!inode_quota_active(inode))
2134                 return 0;
2135
2136         if (i_uid_needs_update(idmap, iattr, inode)) {
2137                 kuid_t kuid = from_vfsuid(idmap, i_user_ns(inode),
2138                                           iattr->ia_vfsuid);
2139
2140                 dquot = dqget(sb, make_kqid_uid(kuid));
2141                 if (IS_ERR(dquot)) {
2142                         if (PTR_ERR(dquot) != -ESRCH) {
2143                                 ret = PTR_ERR(dquot);
2144                                 goto out_put;
2145                         }
2146                         dquot = NULL;
2147                 }
2148                 transfer_to[USRQUOTA] = dquot;
2149         }
2150         if (i_gid_needs_update(idmap, iattr, inode)) {
2151                 kgid_t kgid = from_vfsgid(idmap, i_user_ns(inode),
2152                                           iattr->ia_vfsgid);
2153
2154                 dquot = dqget(sb, make_kqid_gid(kgid));
2155                 if (IS_ERR(dquot)) {
2156                         if (PTR_ERR(dquot) != -ESRCH) {
2157                                 ret = PTR_ERR(dquot);
2158                                 goto out_put;
2159                         }
2160                         dquot = NULL;
2161                 }
2162                 transfer_to[GRPQUOTA] = dquot;
2163         }
2164         ret = __dquot_transfer(inode, transfer_to);
2165 out_put:
2166         dqput_all(transfer_to);
2167         return ret;
2168 }
2169 EXPORT_SYMBOL(dquot_transfer);
2170
2171 /*
2172  * Write info of quota file to disk
2173  */
2174 int dquot_commit_info(struct super_block *sb, int type)
2175 {
2176         struct quota_info *dqopt = sb_dqopt(sb);
2177
2178         return dqopt->ops[type]->write_file_info(sb, type);
2179 }
2180 EXPORT_SYMBOL(dquot_commit_info);
2181
2182 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
2183 {
2184         struct quota_info *dqopt = sb_dqopt(sb);
2185
2186         if (!sb_has_quota_active(sb, qid->type))
2187                 return -ESRCH;
2188         if (!dqopt->ops[qid->type]->get_next_id)
2189                 return -ENOSYS;
2190         return dqopt->ops[qid->type]->get_next_id(sb, qid);
2191 }
2192 EXPORT_SYMBOL(dquot_get_next_id);
2193
2194 /*
2195  * Definitions of diskquota operations.
2196  */
2197 const struct dquot_operations dquot_operations = {
2198         .write_dquot    = dquot_commit,
2199         .acquire_dquot  = dquot_acquire,
2200         .release_dquot  = dquot_release,
2201         .mark_dirty     = dquot_mark_dquot_dirty,
2202         .write_info     = dquot_commit_info,
2203         .alloc_dquot    = dquot_alloc,
2204         .destroy_dquot  = dquot_destroy,
2205         .get_next_id    = dquot_get_next_id,
2206 };
2207 EXPORT_SYMBOL(dquot_operations);
2208
2209 /*
2210  * Generic helper for ->open on filesystems supporting disk quotas.
2211  */
2212 int dquot_file_open(struct inode *inode, struct file *file)
2213 {
2214         int error;
2215
2216         error = generic_file_open(inode, file);
2217         if (!error && (file->f_mode & FMODE_WRITE))
2218                 error = dquot_initialize(inode);
2219         return error;
2220 }
2221 EXPORT_SYMBOL(dquot_file_open);
2222
2223 static void vfs_cleanup_quota_inode(struct super_block *sb, int type)
2224 {
2225         struct quota_info *dqopt = sb_dqopt(sb);
2226         struct inode *inode = dqopt->files[type];
2227
2228         if (!inode)
2229                 return;
2230         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2231                 inode_lock(inode);
2232                 inode->i_flags &= ~S_NOQUOTA;
2233                 inode_unlock(inode);
2234         }
2235         dqopt->files[type] = NULL;
2236         iput(inode);
2237 }
2238
2239 /*
2240  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2241  */
2242 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2243 {
2244         int cnt;
2245         struct quota_info *dqopt = sb_dqopt(sb);
2246
2247         rwsem_assert_held_write(&sb->s_umount);
2248
2249         /* Cannot turn off usage accounting without turning off limits, or
2250          * suspend quotas and simultaneously turn quotas off. */
2251         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2252             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2253             DQUOT_USAGE_ENABLED)))
2254                 return -EINVAL;
2255
2256         /*
2257          * Skip everything if there's nothing to do. We have to do this because
2258          * sometimes we are called when fill_super() failed and calling
2259          * sync_fs() in such cases does no good.
2260          */
2261         if (!sb_any_quota_loaded(sb))
2262                 return 0;
2263
2264         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2265                 if (type != -1 && cnt != type)
2266                         continue;
2267                 if (!sb_has_quota_loaded(sb, cnt))
2268                         continue;
2269
2270                 if (flags & DQUOT_SUSPENDED) {
2271                         spin_lock(&dq_state_lock);
2272                         dqopt->flags |=
2273                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2274                         spin_unlock(&dq_state_lock);
2275                 } else {
2276                         spin_lock(&dq_state_lock);
2277                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2278                         /* Turning off suspended quotas? */
2279                         if (!sb_has_quota_loaded(sb, cnt) &&
2280                             sb_has_quota_suspended(sb, cnt)) {
2281                                 dqopt->flags &= ~dquot_state_flag(
2282                                                         DQUOT_SUSPENDED, cnt);
2283                                 spin_unlock(&dq_state_lock);
2284                                 vfs_cleanup_quota_inode(sb, cnt);
2285                                 continue;
2286                         }
2287                         spin_unlock(&dq_state_lock);
2288                 }
2289
2290                 /* We still have to keep quota loaded? */
2291                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2292                         continue;
2293
2294                 /* Note: these are blocking operations */
2295                 drop_dquot_ref(sb, cnt);
2296                 invalidate_dquots(sb, cnt);
2297                 /*
2298                  * Now all dquots should be invalidated, all writes done so we
2299                  * should be only users of the info. No locks needed.
2300                  */
2301                 if (info_dirty(&dqopt->info[cnt]))
2302                         sb->dq_op->write_info(sb, cnt);
2303                 if (dqopt->ops[cnt]->free_file_info)
2304                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2305                 put_quota_format(dqopt->info[cnt].dqi_format);
2306                 dqopt->info[cnt].dqi_flags = 0;
2307                 dqopt->info[cnt].dqi_igrace = 0;
2308                 dqopt->info[cnt].dqi_bgrace = 0;
2309                 dqopt->ops[cnt] = NULL;
2310         }
2311
2312         /* Skip syncing and setting flags if quota files are hidden */
2313         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2314                 goto put_inodes;
2315
2316         /* Sync the superblock so that buffers with quota data are written to
2317          * disk (and so userspace sees correct data afterwards). */
2318         if (sb->s_op->sync_fs)
2319                 sb->s_op->sync_fs(sb, 1);
2320         sync_blockdev(sb->s_bdev);
2321         /* Now the quota files are just ordinary files and we can set the
2322          * inode flags back. Moreover we discard the pagecache so that
2323          * userspace sees the writes we did bypassing the pagecache. We
2324          * must also discard the blockdev buffers so that we see the
2325          * changes done by userspace on the next quotaon() */
2326         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2327                 if (!sb_has_quota_loaded(sb, cnt) && dqopt->files[cnt]) {
2328                         inode_lock(dqopt->files[cnt]);
2329                         truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
2330                         inode_unlock(dqopt->files[cnt]);
2331                 }
2332         if (sb->s_bdev)
2333                 invalidate_bdev(sb->s_bdev);
2334 put_inodes:
2335         /* We are done when suspending quotas */
2336         if (flags & DQUOT_SUSPENDED)
2337                 return 0;
2338
2339         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2340                 if (!sb_has_quota_loaded(sb, cnt))
2341                         vfs_cleanup_quota_inode(sb, cnt);
2342         return 0;
2343 }
2344 EXPORT_SYMBOL(dquot_disable);
2345
2346 int dquot_quota_off(struct super_block *sb, int type)
2347 {
2348         return dquot_disable(sb, type,
2349                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2350 }
2351 EXPORT_SYMBOL(dquot_quota_off);
2352
2353 /*
2354  *      Turn quotas on on a device
2355  */
2356
2357 static int vfs_setup_quota_inode(struct inode *inode, int type)
2358 {
2359         struct super_block *sb = inode->i_sb;
2360         struct quota_info *dqopt = sb_dqopt(sb);
2361
2362         if (is_bad_inode(inode))
2363                 return -EUCLEAN;
2364         if (!S_ISREG(inode->i_mode))
2365                 return -EACCES;
2366         if (IS_RDONLY(inode))
2367                 return -EROFS;
2368         if (sb_has_quota_loaded(sb, type))
2369                 return -EBUSY;
2370
2371         /*
2372          * Quota files should never be encrypted.  They should be thought of as
2373          * filesystem metadata, not user data.  New-style internal quota files
2374          * cannot be encrypted by users anyway, but old-style external quota
2375          * files could potentially be incorrectly created in an encrypted
2376          * directory, hence this explicit check.  Some reasons why encrypted
2377          * quota files don't work include: (1) some filesystems that support
2378          * encryption don't handle it in their quota_read and quota_write, and
2379          * (2) cleaning up encrypted quota files at unmount would need special
2380          * consideration, as quota files are cleaned up later than user files.
2381          */
2382         if (IS_ENCRYPTED(inode))
2383                 return -EINVAL;
2384
2385         dqopt->files[type] = igrab(inode);
2386         if (!dqopt->files[type])
2387                 return -EIO;
2388         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2389                 /* We don't want quota and atime on quota files (deadlocks
2390                  * possible) Also nobody should write to the file - we use
2391                  * special IO operations which ignore the immutable bit. */
2392                 inode_lock(inode);
2393                 inode->i_flags |= S_NOQUOTA;
2394                 inode_unlock(inode);
2395                 /*
2396                  * When S_NOQUOTA is set, remove dquot references as no more
2397                  * references can be added
2398                  */
2399                 __dquot_drop(inode);
2400         }
2401         return 0;
2402 }
2403
2404 int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,
2405         unsigned int flags)
2406 {
2407         struct quota_format_type *fmt;
2408         struct quota_info *dqopt = sb_dqopt(sb);
2409         int error;
2410
2411         lockdep_assert_held_write(&sb->s_umount);
2412
2413         /* Just unsuspend quotas? */
2414         if (WARN_ON_ONCE(flags & DQUOT_SUSPENDED))
2415                 return -EINVAL;
2416
2417         fmt = find_quota_format(format_id);
2418         if (!fmt)
2419                 return -ESRCH;
2420         if (!sb->dq_op || !sb->s_qcop ||
2421             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2422                 error = -EINVAL;
2423                 goto out_fmt;
2424         }
2425         /* Filesystems outside of init_user_ns not yet supported */
2426         if (sb->s_user_ns != &init_user_ns) {
2427                 error = -EINVAL;
2428                 goto out_fmt;
2429         }
2430         /* Usage always has to be set... */
2431         if (!(flags & DQUOT_USAGE_ENABLED)) {
2432                 error = -EINVAL;
2433                 goto out_fmt;
2434         }
2435         if (sb_has_quota_loaded(sb, type)) {
2436                 error = -EBUSY;
2437                 goto out_fmt;
2438         }
2439
2440         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2441                 /* As we bypass the pagecache we must now flush all the
2442                  * dirty data and invalidate caches so that kernel sees
2443                  * changes from userspace. It is not enough to just flush
2444                  * the quota file since if blocksize < pagesize, invalidation
2445                  * of the cache could fail because of other unrelated dirty
2446                  * data */
2447                 sync_filesystem(sb);
2448                 invalidate_bdev(sb->s_bdev);
2449         }
2450
2451         error = -EINVAL;
2452         if (!fmt->qf_ops->check_quota_file(sb, type))
2453                 goto out_fmt;
2454
2455         dqopt->ops[type] = fmt->qf_ops;
2456         dqopt->info[type].dqi_format = fmt;
2457         dqopt->info[type].dqi_fmt_id = format_id;
2458         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2459         error = dqopt->ops[type]->read_file_info(sb, type);
2460         if (error < 0)
2461                 goto out_fmt;
2462         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2463                 spin_lock(&dq_data_lock);
2464                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2465                 spin_unlock(&dq_data_lock);
2466         }
2467         spin_lock(&dq_state_lock);
2468         dqopt->flags |= dquot_state_flag(flags, type);
2469         spin_unlock(&dq_state_lock);
2470
2471         error = add_dquot_ref(sb, type);
2472         if (error)
2473                 dquot_disable(sb, type,
2474                               DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2475
2476         return error;
2477 out_fmt:
2478         put_quota_format(fmt);
2479
2480         return error;
2481 }
2482 EXPORT_SYMBOL(dquot_load_quota_sb);
2483
2484 /*
2485  * More powerful function for turning on quotas on given quota inode allowing
2486  * setting of individual quota flags
2487  */
2488 int dquot_load_quota_inode(struct inode *inode, int type, int format_id,
2489         unsigned int flags)
2490 {
2491         int err;
2492
2493         err = vfs_setup_quota_inode(inode, type);
2494         if (err < 0)
2495                 return err;
2496         err = dquot_load_quota_sb(inode->i_sb, type, format_id, flags);
2497         if (err < 0)
2498                 vfs_cleanup_quota_inode(inode->i_sb, type);
2499         return err;
2500 }
2501 EXPORT_SYMBOL(dquot_load_quota_inode);
2502
2503 /* Reenable quotas on remount RW */
2504 int dquot_resume(struct super_block *sb, int type)
2505 {
2506         struct quota_info *dqopt = sb_dqopt(sb);
2507         int ret = 0, cnt;
2508         unsigned int flags;
2509
2510         rwsem_assert_held_write(&sb->s_umount);
2511
2512         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2513                 if (type != -1 && cnt != type)
2514                         continue;
2515                 if (!sb_has_quota_suspended(sb, cnt))
2516                         continue;
2517
2518                 spin_lock(&dq_state_lock);
2519                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2520                                                         DQUOT_LIMITS_ENABLED,
2521                                                         cnt);
2522                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2523                 spin_unlock(&dq_state_lock);
2524
2525                 flags = dquot_generic_flag(flags, cnt);
2526                 ret = dquot_load_quota_sb(sb, cnt, dqopt->info[cnt].dqi_fmt_id,
2527                                           flags);
2528                 if (ret < 0)
2529                         vfs_cleanup_quota_inode(sb, cnt);
2530         }
2531
2532         return ret;
2533 }
2534 EXPORT_SYMBOL(dquot_resume);
2535
2536 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2537                    const struct path *path)
2538 {
2539         int error = security_quota_on(path->dentry);
2540         if (error)
2541                 return error;
2542         /* Quota file not on the same filesystem? */
2543         if (path->dentry->d_sb != sb)
2544                 error = -EXDEV;
2545         else
2546                 error = dquot_load_quota_inode(d_inode(path->dentry), type,
2547                                              format_id, DQUOT_USAGE_ENABLED |
2548                                              DQUOT_LIMITS_ENABLED);
2549         return error;
2550 }
2551 EXPORT_SYMBOL(dquot_quota_on);
2552
2553 /*
2554  * This function is used when filesystem needs to initialize quotas
2555  * during mount time.
2556  */
2557 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2558                 int format_id, int type)
2559 {
2560         struct dentry *dentry;
2561         int error;
2562
2563         dentry = lookup_positive_unlocked(qf_name, sb->s_root, strlen(qf_name));
2564         if (IS_ERR(dentry))
2565                 return PTR_ERR(dentry);
2566
2567         error = security_quota_on(dentry);
2568         if (!error)
2569                 error = dquot_load_quota_inode(d_inode(dentry), type, format_id,
2570                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2571
2572         dput(dentry);
2573         return error;
2574 }
2575 EXPORT_SYMBOL(dquot_quota_on_mount);
2576
2577 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2578 {
2579         int ret;
2580         int type;
2581         struct quota_info *dqopt = sb_dqopt(sb);
2582
2583         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2584                 return -ENOSYS;
2585         /* Accounting cannot be turned on while fs is mounted */
2586         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2587         if (!flags)
2588                 return -EINVAL;
2589         for (type = 0; type < MAXQUOTAS; type++) {
2590                 if (!(flags & qtype_enforce_flag(type)))
2591                         continue;
2592                 /* Can't enforce without accounting */
2593                 if (!sb_has_quota_usage_enabled(sb, type)) {
2594                         ret = -EINVAL;
2595                         goto out_err;
2596                 }
2597                 if (sb_has_quota_limits_enabled(sb, type)) {
2598                         /* compatible with XFS */
2599                         ret = -EEXIST;
2600                         goto out_err;
2601                 }
2602                 spin_lock(&dq_state_lock);
2603                 dqopt->flags |= dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2604                 spin_unlock(&dq_state_lock);
2605         }
2606         return 0;
2607 out_err:
2608         /* Backout enforcement enablement we already did */
2609         for (type--; type >= 0; type--)  {
2610                 if (flags & qtype_enforce_flag(type))
2611                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2612         }
2613         return ret;
2614 }
2615
2616 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2617 {
2618         int ret;
2619         int type;
2620         struct quota_info *dqopt = sb_dqopt(sb);
2621
2622         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2623                 return -ENOSYS;
2624         /*
2625          * We don't support turning off accounting via quotactl. In principle
2626          * quota infrastructure can do this but filesystems don't expect
2627          * userspace to be able to do it.
2628          */
2629         if (flags &
2630                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2631                 return -EOPNOTSUPP;
2632
2633         /* Filter out limits not enabled */
2634         for (type = 0; type < MAXQUOTAS; type++)
2635                 if (!sb_has_quota_limits_enabled(sb, type))
2636                         flags &= ~qtype_enforce_flag(type);
2637         /* Nothing left? */
2638         if (!flags)
2639                 return -EEXIST;
2640         for (type = 0; type < MAXQUOTAS; type++) {
2641                 if (flags & qtype_enforce_flag(type)) {
2642                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2643                         if (ret < 0)
2644                                 goto out_err;
2645                 }
2646         }
2647         return 0;
2648 out_err:
2649         /* Backout enforcement disabling we already did */
2650         for (type--; type >= 0; type--)  {
2651                 if (flags & qtype_enforce_flag(type)) {
2652                         spin_lock(&dq_state_lock);
2653                         dqopt->flags |=
2654                                 dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2655                         spin_unlock(&dq_state_lock);
2656                 }
2657         }
2658         return ret;
2659 }
2660
2661 /* Generic routine for getting common part of quota structure */
2662 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2663 {
2664         struct mem_dqblk *dm = &dquot->dq_dqb;
2665
2666         memset(di, 0, sizeof(*di));
2667         spin_lock(&dquot->dq_dqb_lock);
2668         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2669         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2670         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2671         di->d_ino_softlimit = dm->dqb_isoftlimit;
2672         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2673         di->d_ino_count = dm->dqb_curinodes;
2674         di->d_spc_timer = dm->dqb_btime;
2675         di->d_ino_timer = dm->dqb_itime;
2676         spin_unlock(&dquot->dq_dqb_lock);
2677 }
2678
2679 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2680                     struct qc_dqblk *di)
2681 {
2682         struct dquot *dquot;
2683
2684         dquot = dqget(sb, qid);
2685         if (IS_ERR(dquot))
2686                 return PTR_ERR(dquot);
2687         do_get_dqblk(dquot, di);
2688         dqput(dquot);
2689
2690         return 0;
2691 }
2692 EXPORT_SYMBOL(dquot_get_dqblk);
2693
2694 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2695                          struct qc_dqblk *di)
2696 {
2697         struct dquot *dquot;
2698         int err;
2699
2700         if (!sb->dq_op->get_next_id)
2701                 return -ENOSYS;
2702         err = sb->dq_op->get_next_id(sb, qid);
2703         if (err < 0)
2704                 return err;
2705         dquot = dqget(sb, *qid);
2706         if (IS_ERR(dquot))
2707                 return PTR_ERR(dquot);
2708         do_get_dqblk(dquot, di);
2709         dqput(dquot);
2710
2711         return 0;
2712 }
2713 EXPORT_SYMBOL(dquot_get_next_dqblk);
2714
2715 #define VFS_QC_MASK \
2716         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2717          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2718          QC_SPC_TIMER | QC_INO_TIMER)
2719
2720 /* Generic routine for setting common part of quota structure */
2721 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2722 {
2723         struct mem_dqblk *dm = &dquot->dq_dqb;
2724         int check_blim = 0, check_ilim = 0;
2725         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2726         int ret;
2727
2728         if (di->d_fieldmask & ~VFS_QC_MASK)
2729                 return -EINVAL;
2730
2731         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2732              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2733             ((di->d_fieldmask & QC_SPC_HARD) &&
2734              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2735             ((di->d_fieldmask & QC_INO_SOFT) &&
2736              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2737             ((di->d_fieldmask & QC_INO_HARD) &&
2738              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2739                 return -ERANGE;
2740
2741         spin_lock(&dquot->dq_dqb_lock);
2742         if (di->d_fieldmask & QC_SPACE) {
2743                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2744                 check_blim = 1;
2745                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2746         }
2747
2748         if (di->d_fieldmask & QC_SPC_SOFT)
2749                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2750         if (di->d_fieldmask & QC_SPC_HARD)
2751                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2752         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2753                 check_blim = 1;
2754                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2755         }
2756
2757         if (di->d_fieldmask & QC_INO_COUNT) {
2758                 dm->dqb_curinodes = di->d_ino_count;
2759                 check_ilim = 1;
2760                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2761         }
2762
2763         if (di->d_fieldmask & QC_INO_SOFT)
2764                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2765         if (di->d_fieldmask & QC_INO_HARD)
2766                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2767         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2768                 check_ilim = 1;
2769                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2770         }
2771
2772         if (di->d_fieldmask & QC_SPC_TIMER) {
2773                 dm->dqb_btime = di->d_spc_timer;
2774                 check_blim = 1;
2775                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2776         }
2777
2778         if (di->d_fieldmask & QC_INO_TIMER) {
2779                 dm->dqb_itime = di->d_ino_timer;
2780                 check_ilim = 1;
2781                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2782         }
2783
2784         if (check_blim) {
2785                 if (!dm->dqb_bsoftlimit ||
2786                     dm->dqb_curspace + dm->dqb_rsvspace <= dm->dqb_bsoftlimit) {
2787                         dm->dqb_btime = 0;
2788                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2789                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2790                         /* Set grace only if user hasn't provided his own... */
2791                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2792         }
2793         if (check_ilim) {
2794                 if (!dm->dqb_isoftlimit ||
2795                     dm->dqb_curinodes <= dm->dqb_isoftlimit) {
2796                         dm->dqb_itime = 0;
2797                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2798                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2799                         /* Set grace only if user hasn't provided his own... */
2800                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2801         }
2802         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2803             dm->dqb_isoftlimit)
2804                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2805         else
2806                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2807         spin_unlock(&dquot->dq_dqb_lock);
2808         ret = mark_dquot_dirty(dquot);
2809         if (ret < 0)
2810                 return ret;
2811         return 0;
2812 }
2813
2814 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2815                   struct qc_dqblk *di)
2816 {
2817         struct dquot *dquot;
2818         int rc;
2819
2820         dquot = dqget(sb, qid);
2821         if (IS_ERR(dquot)) {
2822                 rc = PTR_ERR(dquot);
2823                 goto out;
2824         }
2825         rc = do_set_dqblk(dquot, di);
2826         dqput(dquot);
2827 out:
2828         return rc;
2829 }
2830 EXPORT_SYMBOL(dquot_set_dqblk);
2831
2832 /* Generic routine for getting common part of quota file information */
2833 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2834 {
2835         struct mem_dqinfo *mi;
2836         struct qc_type_state *tstate;
2837         struct quota_info *dqopt = sb_dqopt(sb);
2838         int type;
2839
2840         memset(state, 0, sizeof(*state));
2841         for (type = 0; type < MAXQUOTAS; type++) {
2842                 if (!sb_has_quota_active(sb, type))
2843                         continue;
2844                 tstate = state->s_state + type;
2845                 mi = sb_dqopt(sb)->info + type;
2846                 tstate->flags = QCI_ACCT_ENABLED;
2847                 spin_lock(&dq_data_lock);
2848                 if (mi->dqi_flags & DQF_SYS_FILE)
2849                         tstate->flags |= QCI_SYSFILE;
2850                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2851                         tstate->flags |= QCI_ROOT_SQUASH;
2852                 if (sb_has_quota_limits_enabled(sb, type))
2853                         tstate->flags |= QCI_LIMITS_ENFORCED;
2854                 tstate->spc_timelimit = mi->dqi_bgrace;
2855                 tstate->ino_timelimit = mi->dqi_igrace;
2856                 if (dqopt->files[type]) {
2857                         tstate->ino = dqopt->files[type]->i_ino;
2858                         tstate->blocks = dqopt->files[type]->i_blocks;
2859                 }
2860                 tstate->nextents = 1;   /* We don't know... */
2861                 spin_unlock(&dq_data_lock);
2862         }
2863         return 0;
2864 }
2865 EXPORT_SYMBOL(dquot_get_state);
2866
2867 /* Generic routine for setting common part of quota file information */
2868 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2869 {
2870         struct mem_dqinfo *mi;
2871
2872         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2873             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2874                 return -EINVAL;
2875         if (!sb_has_quota_active(sb, type))
2876                 return -ESRCH;
2877         mi = sb_dqopt(sb)->info + type;
2878         if (ii->i_fieldmask & QC_FLAGS) {
2879                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2880                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2881                         return -EINVAL;
2882         }
2883         spin_lock(&dq_data_lock);
2884         if (ii->i_fieldmask & QC_SPC_TIMER)
2885                 mi->dqi_bgrace = ii->i_spc_timelimit;
2886         if (ii->i_fieldmask & QC_INO_TIMER)
2887                 mi->dqi_igrace = ii->i_ino_timelimit;
2888         if (ii->i_fieldmask & QC_FLAGS) {
2889                 if (ii->i_flags & QCI_ROOT_SQUASH)
2890                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2891                 else
2892                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2893         }
2894         spin_unlock(&dq_data_lock);
2895         mark_info_dirty(sb, type);
2896         /* Force write to disk */
2897         return sb->dq_op->write_info(sb, type);
2898 }
2899 EXPORT_SYMBOL(dquot_set_dqinfo);
2900
2901 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2902         .quota_enable   = dquot_quota_enable,
2903         .quota_disable  = dquot_quota_disable,
2904         .quota_sync     = dquot_quota_sync,
2905         .get_state      = dquot_get_state,
2906         .set_info       = dquot_set_dqinfo,
2907         .get_dqblk      = dquot_get_dqblk,
2908         .get_nextdqblk  = dquot_get_next_dqblk,
2909         .set_dqblk      = dquot_set_dqblk
2910 };
2911 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2912
2913 static int do_proc_dqstats(const struct ctl_table *table, int write,
2914                      void *buffer, size_t *lenp, loff_t *ppos)
2915 {
2916         unsigned int type = (unsigned long *)table->data - dqstats.stat;
2917         s64 value = percpu_counter_sum(&dqstats.counter[type]);
2918
2919         /* Filter negative values for non-monotonic counters */
2920         if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
2921                           type == DQST_FREE_DQUOTS))
2922                 value = 0;
2923
2924         /* Update global table */
2925         dqstats.stat[type] = value;
2926         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
2927 }
2928
2929 static struct ctl_table fs_dqstats_table[] = {
2930         {
2931                 .procname       = "lookups",
2932                 .data           = &dqstats.stat[DQST_LOOKUPS],
2933                 .maxlen         = sizeof(unsigned long),
2934                 .mode           = 0444,
2935                 .proc_handler   = do_proc_dqstats,
2936         },
2937         {
2938                 .procname       = "drops",
2939                 .data           = &dqstats.stat[DQST_DROPS],
2940                 .maxlen         = sizeof(unsigned long),
2941                 .mode           = 0444,
2942                 .proc_handler   = do_proc_dqstats,
2943         },
2944         {
2945                 .procname       = "reads",
2946                 .data           = &dqstats.stat[DQST_READS],
2947                 .maxlen         = sizeof(unsigned long),
2948                 .mode           = 0444,
2949                 .proc_handler   = do_proc_dqstats,
2950         },
2951         {
2952                 .procname       = "writes",
2953                 .data           = &dqstats.stat[DQST_WRITES],
2954                 .maxlen         = sizeof(unsigned long),
2955                 .mode           = 0444,
2956                 .proc_handler   = do_proc_dqstats,
2957         },
2958         {
2959                 .procname       = "cache_hits",
2960                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2961                 .maxlen         = sizeof(unsigned long),
2962                 .mode           = 0444,
2963                 .proc_handler   = do_proc_dqstats,
2964         },
2965         {
2966                 .procname       = "allocated_dquots",
2967                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2968                 .maxlen         = sizeof(unsigned long),
2969                 .mode           = 0444,
2970                 .proc_handler   = do_proc_dqstats,
2971         },
2972         {
2973                 .procname       = "free_dquots",
2974                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2975                 .maxlen         = sizeof(unsigned long),
2976                 .mode           = 0444,
2977                 .proc_handler   = do_proc_dqstats,
2978         },
2979         {
2980                 .procname       = "syncs",
2981                 .data           = &dqstats.stat[DQST_SYNCS],
2982                 .maxlen         = sizeof(unsigned long),
2983                 .mode           = 0444,
2984                 .proc_handler   = do_proc_dqstats,
2985         },
2986 #ifdef CONFIG_PRINT_QUOTA_WARNING
2987         {
2988                 .procname       = "warnings",
2989                 .data           = &flag_print_warnings,
2990                 .maxlen         = sizeof(int),
2991                 .mode           = 0644,
2992                 .proc_handler   = proc_dointvec,
2993         },
2994 #endif
2995 };
2996
2997 static int __init dquot_init(void)
2998 {
2999         int i, ret;
3000         unsigned long nr_hash, order;
3001         struct shrinker *dqcache_shrinker;
3002
3003         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
3004
3005         register_sysctl_init("fs/quota", fs_dqstats_table);
3006
3007         dquot_cachep = kmem_cache_create("dquot",
3008                         sizeof(struct dquot), sizeof(unsigned long) * 4,
3009                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
3010                                 SLAB_PANIC),
3011                         NULL);
3012
3013         order = 0;
3014         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_KERNEL, order);
3015         if (!dquot_hash)
3016                 panic("Cannot create dquot hash table");
3017
3018         ret = percpu_counter_init_many(dqstats.counter, 0, GFP_KERNEL,
3019                                        _DQST_DQSTAT_LAST);
3020         if (ret)
3021                 panic("Cannot create dquot stat counters");
3022
3023         /* Find power-of-two hlist_heads which can fit into allocation */
3024         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
3025         dq_hash_bits = ilog2(nr_hash);
3026
3027         nr_hash = 1UL << dq_hash_bits;
3028         dq_hash_mask = nr_hash - 1;
3029         for (i = 0; i < nr_hash; i++)
3030                 INIT_HLIST_HEAD(dquot_hash + i);
3031
3032         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
3033                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
3034
3035         dqcache_shrinker = shrinker_alloc(0, "dquota-cache");
3036         if (!dqcache_shrinker)
3037                 panic("Cannot allocate dquot shrinker");
3038
3039         dqcache_shrinker->count_objects = dqcache_shrink_count;
3040         dqcache_shrinker->scan_objects = dqcache_shrink_scan;
3041
3042         shrinker_register(dqcache_shrinker);
3043
3044         return 0;
3045 }
3046 fs_initcall(dquot_init);
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