quota: Do not dirty bad dquots
[sfrench/cifs-2.6.git] / fs / quota / dquot.c
1 /*
2  * Implementation of the diskquota system for the LINUX operating system. QUOTA
3  * is implemented using the BSD system call interface as the means of
4  * communication with the user level. This file contains the generic routines
5  * called by the different filesystems on allocation of an inode or block.
6  * These routines take care of the administration needed to have a consistent
7  * diskquota tracking system. The ideas of both user and group quotas are based
8  * on the Melbourne quota system as used on BSD derived systems. The internal
9  * implementation is based on one of the several variants of the LINUX
10  * inode-subsystem with added complexity of the diskquota system.
11  * 
12  * Author:      Marco van Wieringen <mvw@planets.elm.net>
13  *
14  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
15  *
16  *              Revised list management to avoid races
17  *              -- Bill Hawes, <whawes@star.net>, 9/98
18  *
19  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
20  *              As the consequence the locking was moved from dquot_decr_...(),
21  *              dquot_incr_...() to calling functions.
22  *              invalidate_dquots() now writes modified dquots.
23  *              Serialized quota_off() and quota_on() for mount point.
24  *              Fixed a few bugs in grow_dquots().
25  *              Fixed deadlock in write_dquot() - we no longer account quotas on
26  *              quota files
27  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
28  *              add_dquot_ref() restarts after blocking
29  *              Added check for bogus uid and fixed check for group in quotactl.
30  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
31  *
32  *              Used struct list_head instead of own list struct
33  *              Invalidation of referenced dquots is no longer possible
34  *              Improved free_dquots list management
35  *              Quota and i_blocks are now updated in one place to avoid races
36  *              Warnings are now delayed so we won't block in critical section
37  *              Write updated not to require dquot lock
38  *              Jan Kara, <jack@suse.cz>, 9/2000
39  *
40  *              Added dynamic quota structure allocation
41  *              Jan Kara <jack@suse.cz> 12/2000
42  *
43  *              Rewritten quota interface. Implemented new quota format and
44  *              formats registering.
45  *              Jan Kara, <jack@suse.cz>, 2001,2002
46  *
47  *              New SMP locking.
48  *              Jan Kara, <jack@suse.cz>, 10/2002
49  *
50  *              Added journalled quota support, fix lock inversion problems
51  *              Jan Kara, <jack@suse.cz>, 2003,2004
52  *
53  * (C) Copyright 1994 - 1997 Marco van Wieringen 
54  */
55
56 #include <linux/errno.h>
57 #include <linux/kernel.h>
58 #include <linux/fs.h>
59 #include <linux/mount.h>
60 #include <linux/mm.h>
61 #include <linux/time.h>
62 #include <linux/types.h>
63 #include <linux/string.h>
64 #include <linux/fcntl.h>
65 #include <linux/stat.h>
66 #include <linux/tty.h>
67 #include <linux/file.h>
68 #include <linux/slab.h>
69 #include <linux/sysctl.h>
70 #include <linux/init.h>
71 #include <linux/module.h>
72 #include <linux/proc_fs.h>
73 #include <linux/security.h>
74 #include <linux/sched.h>
75 #include <linux/cred.h>
76 #include <linux/kmod.h>
77 #include <linux/namei.h>
78 #include <linux/capability.h>
79 #include <linux/quotaops.h>
80 #include "../internal.h" /* ugh */
81
82 #include <linux/uaccess.h>
83
84 /*
85  * There are three quota SMP locks. dq_list_lock protects all lists with quotas
86  * and quota formats.
87  * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
88  * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
89  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
90  * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
91  * modifications of quota state (on quotaon and quotaoff) and readers who care
92  * about latest values take it as well.
93  *
94  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
95  *   dq_list_lock > dq_state_lock
96  *
97  * Note that some things (eg. sb pointer, type, id) doesn't change during
98  * the life of the dquot structure and so needn't to be protected by a lock
99  *
100  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
101  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
102  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
103  * inode and before dropping dquot references to avoid use of dquots after
104  * they are freed. dq_data_lock is used to serialize the pointer setting and
105  * clearing operations.
106  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
107  * inode is a quota file). Functions adding pointers from inode to dquots have
108  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
109  * have to do all pointer modifications before dropping dq_data_lock. This makes
110  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
111  * then drops all pointers to dquots from an inode.
112  *
113  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
114  * memory (or space for it is being allocated) on the first dqget(), when it is
115  * being written out, and when it is being released on the last dqput(). The
116  * allocation and release operations are serialized by the dq_lock and by
117  * checking the use count in dquot_release().
118  *
119  * Lock ordering (including related VFS locks) is the following:
120  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
121  */
122
123 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
124 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
125 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
126 EXPORT_SYMBOL(dq_data_lock);
127 DEFINE_STATIC_SRCU(dquot_srcu);
128
129 void __quota_error(struct super_block *sb, const char *func,
130                    const char *fmt, ...)
131 {
132         if (printk_ratelimit()) {
133                 va_list args;
134                 struct va_format vaf;
135
136                 va_start(args, fmt);
137
138                 vaf.fmt = fmt;
139                 vaf.va = &args;
140
141                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
142                        sb->s_id, func, &vaf);
143
144                 va_end(args);
145         }
146 }
147 EXPORT_SYMBOL(__quota_error);
148
149 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
150 static char *quotatypes[] = INITQFNAMES;
151 #endif
152 static struct quota_format_type *quota_formats; /* List of registered formats */
153 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
154
155 /* SLAB cache for dquot structures */
156 static struct kmem_cache *dquot_cachep;
157
158 int register_quota_format(struct quota_format_type *fmt)
159 {
160         spin_lock(&dq_list_lock);
161         fmt->qf_next = quota_formats;
162         quota_formats = fmt;
163         spin_unlock(&dq_list_lock);
164         return 0;
165 }
166 EXPORT_SYMBOL(register_quota_format);
167
168 void unregister_quota_format(struct quota_format_type *fmt)
169 {
170         struct quota_format_type **actqf;
171
172         spin_lock(&dq_list_lock);
173         for (actqf = &quota_formats; *actqf && *actqf != fmt;
174              actqf = &(*actqf)->qf_next)
175                 ;
176         if (*actqf)
177                 *actqf = (*actqf)->qf_next;
178         spin_unlock(&dq_list_lock);
179 }
180 EXPORT_SYMBOL(unregister_quota_format);
181
182 static struct quota_format_type *find_quota_format(int id)
183 {
184         struct quota_format_type *actqf;
185
186         spin_lock(&dq_list_lock);
187         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
188              actqf = actqf->qf_next)
189                 ;
190         if (!actqf || !try_module_get(actqf->qf_owner)) {
191                 int qm;
192
193                 spin_unlock(&dq_list_lock);
194                 
195                 for (qm = 0; module_names[qm].qm_fmt_id &&
196                              module_names[qm].qm_fmt_id != id; qm++)
197                         ;
198                 if (!module_names[qm].qm_fmt_id ||
199                     request_module(module_names[qm].qm_mod_name))
200                         return NULL;
201
202                 spin_lock(&dq_list_lock);
203                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
204                      actqf = actqf->qf_next)
205                         ;
206                 if (actqf && !try_module_get(actqf->qf_owner))
207                         actqf = NULL;
208         }
209         spin_unlock(&dq_list_lock);
210         return actqf;
211 }
212
213 static void put_quota_format(struct quota_format_type *fmt)
214 {
215         module_put(fmt->qf_owner);
216 }
217
218 /*
219  * Dquot List Management:
220  * The quota code uses three lists for dquot management: the inuse_list,
221  * free_dquots, and dquot_hash[] array. A single dquot structure may be
222  * on all three lists, depending on its current state.
223  *
224  * All dquots are placed to the end of inuse_list when first created, and this
225  * list is used for invalidate operation, which must look at every dquot.
226  *
227  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
228  * and this list is searched whenever we need an available dquot.  Dquots are
229  * removed from the list as soon as they are used again, and
230  * dqstats.free_dquots gives the number of dquots on the list. When
231  * dquot is invalidated it's completely released from memory.
232  *
233  * Dquots with a specific identity (device, type and id) are placed on
234  * one of the dquot_hash[] hash chains. The provides an efficient search
235  * mechanism to locate a specific dquot.
236  */
237
238 static LIST_HEAD(inuse_list);
239 static LIST_HEAD(free_dquots);
240 static unsigned int dq_hash_bits, dq_hash_mask;
241 static struct hlist_head *dquot_hash;
242
243 struct dqstats dqstats;
244 EXPORT_SYMBOL(dqstats);
245
246 static qsize_t inode_get_rsv_space(struct inode *inode);
247 static int __dquot_initialize(struct inode *inode, int type);
248
249 static inline unsigned int
250 hashfn(const struct super_block *sb, struct kqid qid)
251 {
252         unsigned int id = from_kqid(&init_user_ns, qid);
253         int type = qid.type;
254         unsigned long tmp;
255
256         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
257         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
258 }
259
260 /*
261  * Following list functions expect dq_list_lock to be held
262  */
263 static inline void insert_dquot_hash(struct dquot *dquot)
264 {
265         struct hlist_head *head;
266         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
267         hlist_add_head(&dquot->dq_hash, head);
268 }
269
270 static inline void remove_dquot_hash(struct dquot *dquot)
271 {
272         hlist_del_init(&dquot->dq_hash);
273 }
274
275 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
276                                 struct kqid qid)
277 {
278         struct hlist_node *node;
279         struct dquot *dquot;
280
281         hlist_for_each (node, dquot_hash+hashent) {
282                 dquot = hlist_entry(node, struct dquot, dq_hash);
283                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
284                         return dquot;
285         }
286         return NULL;
287 }
288
289 /* Add a dquot to the tail of the free list */
290 static inline void put_dquot_last(struct dquot *dquot)
291 {
292         list_add_tail(&dquot->dq_free, &free_dquots);
293         dqstats_inc(DQST_FREE_DQUOTS);
294 }
295
296 static inline void remove_free_dquot(struct dquot *dquot)
297 {
298         if (list_empty(&dquot->dq_free))
299                 return;
300         list_del_init(&dquot->dq_free);
301         dqstats_dec(DQST_FREE_DQUOTS);
302 }
303
304 static inline void put_inuse(struct dquot *dquot)
305 {
306         /* We add to the back of inuse list so we don't have to restart
307          * when traversing this list and we block */
308         list_add_tail(&dquot->dq_inuse, &inuse_list);
309         dqstats_inc(DQST_ALLOC_DQUOTS);
310 }
311
312 static inline void remove_inuse(struct dquot *dquot)
313 {
314         dqstats_dec(DQST_ALLOC_DQUOTS);
315         list_del(&dquot->dq_inuse);
316 }
317 /*
318  * End of list functions needing dq_list_lock
319  */
320
321 static void wait_on_dquot(struct dquot *dquot)
322 {
323         mutex_lock(&dquot->dq_lock);
324         mutex_unlock(&dquot->dq_lock);
325 }
326
327 static inline int dquot_dirty(struct dquot *dquot)
328 {
329         return test_bit(DQ_MOD_B, &dquot->dq_flags);
330 }
331
332 static inline int mark_dquot_dirty(struct dquot *dquot)
333 {
334         return dquot->dq_sb->dq_op->mark_dirty(dquot);
335 }
336
337 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
338 int dquot_mark_dquot_dirty(struct dquot *dquot)
339 {
340         int ret = 1;
341
342         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
343                 return 0;
344
345         /* If quota is dirty already, we don't have to acquire dq_list_lock */
346         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
347                 return 1;
348
349         spin_lock(&dq_list_lock);
350         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
351                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
352                                 info[dquot->dq_id.type].dqi_dirty_list);
353                 ret = 0;
354         }
355         spin_unlock(&dq_list_lock);
356         return ret;
357 }
358 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
359
360 /* Dirtify all the dquots - this can block when journalling */
361 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
362 {
363         int ret, err, cnt;
364
365         ret = err = 0;
366         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
367                 if (dquot[cnt])
368                         /* Even in case of error we have to continue */
369                         ret = mark_dquot_dirty(dquot[cnt]);
370                 if (!err)
371                         err = ret;
372         }
373         return err;
374 }
375
376 static inline void dqput_all(struct dquot **dquot)
377 {
378         unsigned int cnt;
379
380         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
381                 dqput(dquot[cnt]);
382 }
383
384 /* This function needs dq_list_lock */
385 static inline int clear_dquot_dirty(struct dquot *dquot)
386 {
387         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
388                 return 0;
389         list_del_init(&dquot->dq_dirty);
390         return 1;
391 }
392
393 void mark_info_dirty(struct super_block *sb, int type)
394 {
395         spin_lock(&dq_data_lock);
396         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
397         spin_unlock(&dq_data_lock);
398 }
399 EXPORT_SYMBOL(mark_info_dirty);
400
401 /*
402  *      Read dquot from disk and alloc space for it
403  */
404
405 int dquot_acquire(struct dquot *dquot)
406 {
407         int ret = 0, ret2 = 0;
408         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
409
410         mutex_lock(&dquot->dq_lock);
411         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
412                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
413         if (ret < 0)
414                 goto out_iolock;
415         /* Make sure flags update is visible after dquot has been filled */
416         smp_mb__before_atomic();
417         set_bit(DQ_READ_B, &dquot->dq_flags);
418         /* Instantiate dquot if needed */
419         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
420                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
421                 /* Write the info if needed */
422                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
423                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
424                                         dquot->dq_sb, dquot->dq_id.type);
425                 }
426                 if (ret < 0)
427                         goto out_iolock;
428                 if (ret2 < 0) {
429                         ret = ret2;
430                         goto out_iolock;
431                 }
432         }
433         /*
434          * Make sure flags update is visible after on-disk struct has been
435          * allocated. Paired with smp_rmb() in dqget().
436          */
437         smp_mb__before_atomic();
438         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
439 out_iolock:
440         mutex_unlock(&dquot->dq_lock);
441         return ret;
442 }
443 EXPORT_SYMBOL(dquot_acquire);
444
445 /*
446  *      Write dquot to disk
447  */
448 int dquot_commit(struct dquot *dquot)
449 {
450         int ret = 0;
451         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
452
453         mutex_lock(&dquot->dq_lock);
454         spin_lock(&dq_list_lock);
455         if (!clear_dquot_dirty(dquot)) {
456                 spin_unlock(&dq_list_lock);
457                 goto out_lock;
458         }
459         spin_unlock(&dq_list_lock);
460         /* Inactive dquot can be only if there was error during read/init
461          * => we have better not writing it */
462         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
463                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
464         else
465                 ret = -EIO;
466 out_lock:
467         mutex_unlock(&dquot->dq_lock);
468         return ret;
469 }
470 EXPORT_SYMBOL(dquot_commit);
471
472 /*
473  *      Release dquot
474  */
475 int dquot_release(struct dquot *dquot)
476 {
477         int ret = 0, ret2 = 0;
478         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
479
480         mutex_lock(&dquot->dq_lock);
481         /* Check whether we are not racing with some other dqget() */
482         if (atomic_read(&dquot->dq_count) > 1)
483                 goto out_dqlock;
484         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
485                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
486                 /* Write the info */
487                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
488                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
489                                                 dquot->dq_sb, dquot->dq_id.type);
490                 }
491                 if (ret >= 0)
492                         ret = ret2;
493         }
494         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
495 out_dqlock:
496         mutex_unlock(&dquot->dq_lock);
497         return ret;
498 }
499 EXPORT_SYMBOL(dquot_release);
500
501 void dquot_destroy(struct dquot *dquot)
502 {
503         kmem_cache_free(dquot_cachep, dquot);
504 }
505 EXPORT_SYMBOL(dquot_destroy);
506
507 static inline void do_destroy_dquot(struct dquot *dquot)
508 {
509         dquot->dq_sb->dq_op->destroy_dquot(dquot);
510 }
511
512 /* Invalidate all dquots on the list. Note that this function is called after
513  * quota is disabled and pointers from inodes removed so there cannot be new
514  * quota users. There can still be some users of quotas due to inodes being
515  * just deleted or pruned by prune_icache() (those are not attached to any
516  * list) or parallel quotactl call. We have to wait for such users.
517  */
518 static void invalidate_dquots(struct super_block *sb, int type)
519 {
520         struct dquot *dquot, *tmp;
521
522 restart:
523         spin_lock(&dq_list_lock);
524         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
525                 if (dquot->dq_sb != sb)
526                         continue;
527                 if (dquot->dq_id.type != type)
528                         continue;
529                 /* Wait for dquot users */
530                 if (atomic_read(&dquot->dq_count)) {
531                         DEFINE_WAIT(wait);
532
533                         dqgrab(dquot);
534                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
535                                         TASK_UNINTERRUPTIBLE);
536                         spin_unlock(&dq_list_lock);
537                         /* Once dqput() wakes us up, we know it's time to free
538                          * the dquot.
539                          * IMPORTANT: we rely on the fact that there is always
540                          * at most one process waiting for dquot to free.
541                          * Otherwise dq_count would be > 1 and we would never
542                          * wake up.
543                          */
544                         if (atomic_read(&dquot->dq_count) > 1)
545                                 schedule();
546                         finish_wait(&dquot->dq_wait_unused, &wait);
547                         dqput(dquot);
548                         /* At this moment dquot() need not exist (it could be
549                          * reclaimed by prune_dqcache(). Hence we must
550                          * restart. */
551                         goto restart;
552                 }
553                 /*
554                  * Quota now has no users and it has been written on last
555                  * dqput()
556                  */
557                 remove_dquot_hash(dquot);
558                 remove_free_dquot(dquot);
559                 remove_inuse(dquot);
560                 do_destroy_dquot(dquot);
561         }
562         spin_unlock(&dq_list_lock);
563 }
564
565 /* Call callback for every active dquot on given filesystem */
566 int dquot_scan_active(struct super_block *sb,
567                       int (*fn)(struct dquot *dquot, unsigned long priv),
568                       unsigned long priv)
569 {
570         struct dquot *dquot, *old_dquot = NULL;
571         int ret = 0;
572
573         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
574
575         spin_lock(&dq_list_lock);
576         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
577                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
578                         continue;
579                 if (dquot->dq_sb != sb)
580                         continue;
581                 /* Now we have active dquot so we can just increase use count */
582                 atomic_inc(&dquot->dq_count);
583                 spin_unlock(&dq_list_lock);
584                 dqstats_inc(DQST_LOOKUPS);
585                 dqput(old_dquot);
586                 old_dquot = dquot;
587                 /*
588                  * ->release_dquot() can be racing with us. Our reference
589                  * protects us from new calls to it so just wait for any
590                  * outstanding call and recheck the DQ_ACTIVE_B after that.
591                  */
592                 wait_on_dquot(dquot);
593                 if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
594                         ret = fn(dquot, priv);
595                         if (ret < 0)
596                                 goto out;
597                 }
598                 spin_lock(&dq_list_lock);
599                 /* We are safe to continue now because our dquot could not
600                  * be moved out of the inuse list while we hold the reference */
601         }
602         spin_unlock(&dq_list_lock);
603 out:
604         dqput(old_dquot);
605         return ret;
606 }
607 EXPORT_SYMBOL(dquot_scan_active);
608
609 /* Write all dquot structures to quota files */
610 int dquot_writeback_dquots(struct super_block *sb, int type)
611 {
612         struct list_head *dirty;
613         struct dquot *dquot;
614         struct quota_info *dqopt = sb_dqopt(sb);
615         int cnt;
616         int err, ret = 0;
617
618         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
619
620         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
621                 if (type != -1 && cnt != type)
622                         continue;
623                 if (!sb_has_quota_active(sb, cnt))
624                         continue;
625                 spin_lock(&dq_list_lock);
626                 dirty = &dqopt->info[cnt].dqi_dirty_list;
627                 while (!list_empty(dirty)) {
628                         dquot = list_first_entry(dirty, struct dquot,
629                                                  dq_dirty);
630
631                         WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
632
633                         /* Now we have active dquot from which someone is
634                          * holding reference so we can safely just increase
635                          * use count */
636                         dqgrab(dquot);
637                         spin_unlock(&dq_list_lock);
638                         dqstats_inc(DQST_LOOKUPS);
639                         err = sb->dq_op->write_dquot(dquot);
640                         if (!ret && err)
641                                 ret = err;
642                         dqput(dquot);
643                         spin_lock(&dq_list_lock);
644                 }
645                 spin_unlock(&dq_list_lock);
646         }
647
648         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
649                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
650                     && info_dirty(&dqopt->info[cnt]))
651                         sb->dq_op->write_info(sb, cnt);
652         dqstats_inc(DQST_SYNCS);
653
654         return ret;
655 }
656 EXPORT_SYMBOL(dquot_writeback_dquots);
657
658 /* Write all dquot structures to disk and make them visible from userspace */
659 int dquot_quota_sync(struct super_block *sb, int type)
660 {
661         struct quota_info *dqopt = sb_dqopt(sb);
662         int cnt;
663         int ret;
664
665         ret = dquot_writeback_dquots(sb, type);
666         if (ret)
667                 return ret;
668         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
669                 return 0;
670
671         /* This is not very clever (and fast) but currently I don't know about
672          * any other simple way of getting quota data to disk and we must get
673          * them there for userspace to be visible... */
674         if (sb->s_op->sync_fs)
675                 sb->s_op->sync_fs(sb, 1);
676         sync_blockdev(sb->s_bdev);
677
678         /*
679          * Now when everything is written we can discard the pagecache so
680          * that userspace sees the changes.
681          */
682         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
683                 if (type != -1 && cnt != type)
684                         continue;
685                 if (!sb_has_quota_active(sb, cnt))
686                         continue;
687                 inode_lock(dqopt->files[cnt]);
688                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
689                 inode_unlock(dqopt->files[cnt]);
690         }
691
692         return 0;
693 }
694 EXPORT_SYMBOL(dquot_quota_sync);
695
696 static unsigned long
697 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
698 {
699         struct list_head *head;
700         struct dquot *dquot;
701         unsigned long freed = 0;
702
703         spin_lock(&dq_list_lock);
704         head = free_dquots.prev;
705         while (head != &free_dquots && sc->nr_to_scan) {
706                 dquot = list_entry(head, struct dquot, dq_free);
707                 remove_dquot_hash(dquot);
708                 remove_free_dquot(dquot);
709                 remove_inuse(dquot);
710                 do_destroy_dquot(dquot);
711                 sc->nr_to_scan--;
712                 freed++;
713                 head = free_dquots.prev;
714         }
715         spin_unlock(&dq_list_lock);
716         return freed;
717 }
718
719 static unsigned long
720 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
721 {
722         return vfs_pressure_ratio(
723         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
724 }
725
726 static struct shrinker dqcache_shrinker = {
727         .count_objects = dqcache_shrink_count,
728         .scan_objects = dqcache_shrink_scan,
729         .seeks = DEFAULT_SEEKS,
730 };
731
732 /*
733  * Put reference to dquot
734  */
735 void dqput(struct dquot *dquot)
736 {
737         int ret;
738
739         if (!dquot)
740                 return;
741 #ifdef CONFIG_QUOTA_DEBUG
742         if (!atomic_read(&dquot->dq_count)) {
743                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
744                             quotatypes[dquot->dq_id.type],
745                             from_kqid(&init_user_ns, dquot->dq_id));
746                 BUG();
747         }
748 #endif
749         dqstats_inc(DQST_DROPS);
750 we_slept:
751         spin_lock(&dq_list_lock);
752         if (atomic_read(&dquot->dq_count) > 1) {
753                 /* We have more than one user... nothing to do */
754                 atomic_dec(&dquot->dq_count);
755                 /* Releasing dquot during quotaoff phase? */
756                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
757                     atomic_read(&dquot->dq_count) == 1)
758                         wake_up(&dquot->dq_wait_unused);
759                 spin_unlock(&dq_list_lock);
760                 return;
761         }
762         /* Need to release dquot? */
763         if (dquot_dirty(dquot)) {
764                 spin_unlock(&dq_list_lock);
765                 /* Commit dquot before releasing */
766                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
767                 if (ret < 0) {
768                         quota_error(dquot->dq_sb, "Can't write quota structure"
769                                     " (error %d). Quota may get out of sync!",
770                                     ret);
771                         /*
772                          * We clear dirty bit anyway, so that we avoid
773                          * infinite loop here
774                          */
775                         spin_lock(&dq_list_lock);
776                         clear_dquot_dirty(dquot);
777                         spin_unlock(&dq_list_lock);
778                 }
779                 goto we_slept;
780         }
781         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
782                 spin_unlock(&dq_list_lock);
783                 dquot->dq_sb->dq_op->release_dquot(dquot);
784                 goto we_slept;
785         }
786         atomic_dec(&dquot->dq_count);
787 #ifdef CONFIG_QUOTA_DEBUG
788         /* sanity check */
789         BUG_ON(!list_empty(&dquot->dq_free));
790 #endif
791         put_dquot_last(dquot);
792         spin_unlock(&dq_list_lock);
793 }
794 EXPORT_SYMBOL(dqput);
795
796 struct dquot *dquot_alloc(struct super_block *sb, int type)
797 {
798         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
799 }
800 EXPORT_SYMBOL(dquot_alloc);
801
802 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
803 {
804         struct dquot *dquot;
805
806         dquot = sb->dq_op->alloc_dquot(sb, type);
807         if(!dquot)
808                 return NULL;
809
810         mutex_init(&dquot->dq_lock);
811         INIT_LIST_HEAD(&dquot->dq_free);
812         INIT_LIST_HEAD(&dquot->dq_inuse);
813         INIT_HLIST_NODE(&dquot->dq_hash);
814         INIT_LIST_HEAD(&dquot->dq_dirty);
815         init_waitqueue_head(&dquot->dq_wait_unused);
816         dquot->dq_sb = sb;
817         dquot->dq_id = make_kqid_invalid(type);
818         atomic_set(&dquot->dq_count, 1);
819
820         return dquot;
821 }
822
823 /*
824  * Get reference to dquot
825  *
826  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
827  * destroying our dquot by:
828  *   a) checking for quota flags under dq_list_lock and
829  *   b) getting a reference to dquot before we release dq_list_lock
830  */
831 struct dquot *dqget(struct super_block *sb, struct kqid qid)
832 {
833         unsigned int hashent = hashfn(sb, qid);
834         struct dquot *dquot, *empty = NULL;
835
836         if (!qid_has_mapping(sb->s_user_ns, qid))
837                 return ERR_PTR(-EINVAL);
838
839         if (!sb_has_quota_active(sb, qid.type))
840                 return ERR_PTR(-ESRCH);
841 we_slept:
842         spin_lock(&dq_list_lock);
843         spin_lock(&dq_state_lock);
844         if (!sb_has_quota_active(sb, qid.type)) {
845                 spin_unlock(&dq_state_lock);
846                 spin_unlock(&dq_list_lock);
847                 dquot = ERR_PTR(-ESRCH);
848                 goto out;
849         }
850         spin_unlock(&dq_state_lock);
851
852         dquot = find_dquot(hashent, sb, qid);
853         if (!dquot) {
854                 if (!empty) {
855                         spin_unlock(&dq_list_lock);
856                         empty = get_empty_dquot(sb, qid.type);
857                         if (!empty)
858                                 schedule();     /* Try to wait for a moment... */
859                         goto we_slept;
860                 }
861                 dquot = empty;
862                 empty = NULL;
863                 dquot->dq_id = qid;
864                 /* all dquots go on the inuse_list */
865                 put_inuse(dquot);
866                 /* hash it first so it can be found */
867                 insert_dquot_hash(dquot);
868                 spin_unlock(&dq_list_lock);
869                 dqstats_inc(DQST_LOOKUPS);
870         } else {
871                 if (!atomic_read(&dquot->dq_count))
872                         remove_free_dquot(dquot);
873                 atomic_inc(&dquot->dq_count);
874                 spin_unlock(&dq_list_lock);
875                 dqstats_inc(DQST_CACHE_HITS);
876                 dqstats_inc(DQST_LOOKUPS);
877         }
878         /* Wait for dq_lock - after this we know that either dquot_release() is
879          * already finished or it will be canceled due to dq_count > 1 test */
880         wait_on_dquot(dquot);
881         /* Read the dquot / allocate space in quota file */
882         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
883                 int err;
884
885                 err = sb->dq_op->acquire_dquot(dquot);
886                 if (err < 0) {
887                         dqput(dquot);
888                         dquot = ERR_PTR(err);
889                         goto out;
890                 }
891         }
892         /*
893          * Make sure following reads see filled structure - paired with
894          * smp_mb__before_atomic() in dquot_acquire().
895          */
896         smp_rmb();
897 #ifdef CONFIG_QUOTA_DEBUG
898         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
899 #endif
900 out:
901         if (empty)
902                 do_destroy_dquot(empty);
903
904         return dquot;
905 }
906 EXPORT_SYMBOL(dqget);
907
908 static inline struct dquot **i_dquot(struct inode *inode)
909 {
910         return inode->i_sb->s_op->get_dquots(inode);
911 }
912
913 static int dqinit_needed(struct inode *inode, int type)
914 {
915         struct dquot * const *dquots;
916         int cnt;
917
918         if (IS_NOQUOTA(inode))
919                 return 0;
920
921         dquots = i_dquot(inode);
922         if (type != -1)
923                 return !dquots[type];
924         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
925                 if (!dquots[cnt])
926                         return 1;
927         return 0;
928 }
929
930 /* This routine is guarded by s_umount semaphore */
931 static void add_dquot_ref(struct super_block *sb, int type)
932 {
933         struct inode *inode, *old_inode = NULL;
934 #ifdef CONFIG_QUOTA_DEBUG
935         int reserved = 0;
936 #endif
937
938         spin_lock(&sb->s_inode_list_lock);
939         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
940                 spin_lock(&inode->i_lock);
941                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
942                     !atomic_read(&inode->i_writecount) ||
943                     !dqinit_needed(inode, type)) {
944                         spin_unlock(&inode->i_lock);
945                         continue;
946                 }
947                 __iget(inode);
948                 spin_unlock(&inode->i_lock);
949                 spin_unlock(&sb->s_inode_list_lock);
950
951 #ifdef CONFIG_QUOTA_DEBUG
952                 if (unlikely(inode_get_rsv_space(inode) > 0))
953                         reserved = 1;
954 #endif
955                 iput(old_inode);
956                 __dquot_initialize(inode, type);
957
958                 /*
959                  * We hold a reference to 'inode' so it couldn't have been
960                  * removed from s_inodes list while we dropped the
961                  * s_inode_list_lock. We cannot iput the inode now as we can be
962                  * holding the last reference and we cannot iput it under
963                  * s_inode_list_lock. So we keep the reference and iput it
964                  * later.
965                  */
966                 old_inode = inode;
967                 spin_lock(&sb->s_inode_list_lock);
968         }
969         spin_unlock(&sb->s_inode_list_lock);
970         iput(old_inode);
971
972 #ifdef CONFIG_QUOTA_DEBUG
973         if (reserved) {
974                 quota_error(sb, "Writes happened before quota was turned on "
975                         "thus quota information is probably inconsistent. "
976                         "Please run quotacheck(8)");
977         }
978 #endif
979 }
980
981 /*
982  * Remove references to dquots from inode and add dquot to list for freeing
983  * if we have the last reference to dquot
984  */
985 static void remove_inode_dquot_ref(struct inode *inode, int type,
986                                    struct list_head *tofree_head)
987 {
988         struct dquot **dquots = i_dquot(inode);
989         struct dquot *dquot = dquots[type];
990
991         if (!dquot)
992                 return;
993
994         dquots[type] = NULL;
995         if (list_empty(&dquot->dq_free)) {
996                 /*
997                  * The inode still has reference to dquot so it can't be in the
998                  * free list
999                  */
1000                 spin_lock(&dq_list_lock);
1001                 list_add(&dquot->dq_free, tofree_head);
1002                 spin_unlock(&dq_list_lock);
1003         } else {
1004                 /*
1005                  * Dquot is already in a list to put so we won't drop the last
1006                  * reference here.
1007                  */
1008                 dqput(dquot);
1009         }
1010 }
1011
1012 /*
1013  * Free list of dquots
1014  * Dquots are removed from inodes and no new references can be got so we are
1015  * the only ones holding reference
1016  */
1017 static void put_dquot_list(struct list_head *tofree_head)
1018 {
1019         struct list_head *act_head;
1020         struct dquot *dquot;
1021
1022         act_head = tofree_head->next;
1023         while (act_head != tofree_head) {
1024                 dquot = list_entry(act_head, struct dquot, dq_free);
1025                 act_head = act_head->next;
1026                 /* Remove dquot from the list so we won't have problems... */
1027                 list_del_init(&dquot->dq_free);
1028                 dqput(dquot);
1029         }
1030 }
1031
1032 static void remove_dquot_ref(struct super_block *sb, int type,
1033                 struct list_head *tofree_head)
1034 {
1035         struct inode *inode;
1036         int reserved = 0;
1037
1038         spin_lock(&sb->s_inode_list_lock);
1039         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1040                 /*
1041                  *  We have to scan also I_NEW inodes because they can already
1042                  *  have quota pointer initialized. Luckily, we need to touch
1043                  *  only quota pointers and these have separate locking
1044                  *  (dq_data_lock).
1045                  */
1046                 spin_lock(&dq_data_lock);
1047                 if (!IS_NOQUOTA(inode)) {
1048                         if (unlikely(inode_get_rsv_space(inode) > 0))
1049                                 reserved = 1;
1050                         remove_inode_dquot_ref(inode, type, tofree_head);
1051                 }
1052                 spin_unlock(&dq_data_lock);
1053         }
1054         spin_unlock(&sb->s_inode_list_lock);
1055 #ifdef CONFIG_QUOTA_DEBUG
1056         if (reserved) {
1057                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1058                         " was disabled thus quota information is probably "
1059                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1060         }
1061 #endif
1062 }
1063
1064 /* Gather all references from inodes and drop them */
1065 static void drop_dquot_ref(struct super_block *sb, int type)
1066 {
1067         LIST_HEAD(tofree_head);
1068
1069         if (sb->dq_op) {
1070                 remove_dquot_ref(sb, type, &tofree_head);
1071                 synchronize_srcu(&dquot_srcu);
1072                 put_dquot_list(&tofree_head);
1073         }
1074 }
1075
1076 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
1077 {
1078         dquot->dq_dqb.dqb_curinodes += number;
1079 }
1080
1081 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
1082 {
1083         dquot->dq_dqb.dqb_curspace += number;
1084 }
1085
1086 static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
1087 {
1088         dquot->dq_dqb.dqb_rsvspace += number;
1089 }
1090
1091 /*
1092  * Claim reserved quota space
1093  */
1094 static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number)
1095 {
1096         if (dquot->dq_dqb.dqb_rsvspace < number) {
1097                 WARN_ON_ONCE(1);
1098                 number = dquot->dq_dqb.dqb_rsvspace;
1099         }
1100         dquot->dq_dqb.dqb_curspace += number;
1101         dquot->dq_dqb.dqb_rsvspace -= number;
1102 }
1103
1104 static void dquot_reclaim_reserved_space(struct dquot *dquot, qsize_t number)
1105 {
1106         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1107                 number = dquot->dq_dqb.dqb_curspace;
1108         dquot->dq_dqb.dqb_rsvspace += number;
1109         dquot->dq_dqb.dqb_curspace -= number;
1110 }
1111
1112 static inline
1113 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1114 {
1115         if (dquot->dq_dqb.dqb_rsvspace >= number)
1116                 dquot->dq_dqb.dqb_rsvspace -= number;
1117         else {
1118                 WARN_ON_ONCE(1);
1119                 dquot->dq_dqb.dqb_rsvspace = 0;
1120         }
1121 }
1122
1123 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1124 {
1125         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1126             dquot->dq_dqb.dqb_curinodes >= number)
1127                 dquot->dq_dqb.dqb_curinodes -= number;
1128         else
1129                 dquot->dq_dqb.dqb_curinodes = 0;
1130         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1131                 dquot->dq_dqb.dqb_itime = (time64_t) 0;
1132         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1133 }
1134
1135 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1136 {
1137         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1138             dquot->dq_dqb.dqb_curspace >= number)
1139                 dquot->dq_dqb.dqb_curspace -= number;
1140         else
1141                 dquot->dq_dqb.dqb_curspace = 0;
1142         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1143                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1144         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1145 }
1146
1147 struct dquot_warn {
1148         struct super_block *w_sb;
1149         struct kqid w_dq_id;
1150         short w_type;
1151 };
1152
1153 static int warning_issued(struct dquot *dquot, const int warntype)
1154 {
1155         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1156                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1157                 ((warntype == QUOTA_NL_IHARDWARN ||
1158                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1159
1160         if (!flag)
1161                 return 0;
1162         return test_and_set_bit(flag, &dquot->dq_flags);
1163 }
1164
1165 #ifdef CONFIG_PRINT_QUOTA_WARNING
1166 static int flag_print_warnings = 1;
1167
1168 static int need_print_warning(struct dquot_warn *warn)
1169 {
1170         if (!flag_print_warnings)
1171                 return 0;
1172
1173         switch (warn->w_dq_id.type) {
1174                 case USRQUOTA:
1175                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1176                 case GRPQUOTA:
1177                         return in_group_p(warn->w_dq_id.gid);
1178                 case PRJQUOTA:
1179                         return 1;
1180         }
1181         return 0;
1182 }
1183
1184 /* Print warning to user which exceeded quota */
1185 static void print_warning(struct dquot_warn *warn)
1186 {
1187         char *msg = NULL;
1188         struct tty_struct *tty;
1189         int warntype = warn->w_type;
1190
1191         if (warntype == QUOTA_NL_IHARDBELOW ||
1192             warntype == QUOTA_NL_ISOFTBELOW ||
1193             warntype == QUOTA_NL_BHARDBELOW ||
1194             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1195                 return;
1196
1197         tty = get_current_tty();
1198         if (!tty)
1199                 return;
1200         tty_write_message(tty, warn->w_sb->s_id);
1201         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1202                 tty_write_message(tty, ": warning, ");
1203         else
1204                 tty_write_message(tty, ": write failed, ");
1205         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1206         switch (warntype) {
1207                 case QUOTA_NL_IHARDWARN:
1208                         msg = " file limit reached.\r\n";
1209                         break;
1210                 case QUOTA_NL_ISOFTLONGWARN:
1211                         msg = " file quota exceeded too long.\r\n";
1212                         break;
1213                 case QUOTA_NL_ISOFTWARN:
1214                         msg = " file quota exceeded.\r\n";
1215                         break;
1216                 case QUOTA_NL_BHARDWARN:
1217                         msg = " block limit reached.\r\n";
1218                         break;
1219                 case QUOTA_NL_BSOFTLONGWARN:
1220                         msg = " block quota exceeded too long.\r\n";
1221                         break;
1222                 case QUOTA_NL_BSOFTWARN:
1223                         msg = " block quota exceeded.\r\n";
1224                         break;
1225         }
1226         tty_write_message(tty, msg);
1227         tty_kref_put(tty);
1228 }
1229 #endif
1230
1231 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1232                             int warntype)
1233 {
1234         if (warning_issued(dquot, warntype))
1235                 return;
1236         warn->w_type = warntype;
1237         warn->w_sb = dquot->dq_sb;
1238         warn->w_dq_id = dquot->dq_id;
1239 }
1240
1241 /*
1242  * Write warnings to the console and send warning messages over netlink.
1243  *
1244  * Note that this function can call into tty and networking code.
1245  */
1246 static void flush_warnings(struct dquot_warn *warn)
1247 {
1248         int i;
1249
1250         for (i = 0; i < MAXQUOTAS; i++) {
1251                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1252                         continue;
1253 #ifdef CONFIG_PRINT_QUOTA_WARNING
1254                 print_warning(&warn[i]);
1255 #endif
1256                 quota_send_warning(warn[i].w_dq_id,
1257                                    warn[i].w_sb->s_dev, warn[i].w_type);
1258         }
1259 }
1260
1261 static int ignore_hardlimit(struct dquot *dquot)
1262 {
1263         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1264
1265         return capable(CAP_SYS_RESOURCE) &&
1266                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1267                 !(info->dqi_flags & DQF_ROOT_SQUASH));
1268 }
1269
1270 /* needs dq_data_lock */
1271 static int check_idq(struct dquot *dquot, qsize_t inodes,
1272                      struct dquot_warn *warn)
1273 {
1274         qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1275
1276         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1277             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1278                 return 0;
1279
1280         if (dquot->dq_dqb.dqb_ihardlimit &&
1281             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1282             !ignore_hardlimit(dquot)) {
1283                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1284                 return -EDQUOT;
1285         }
1286
1287         if (dquot->dq_dqb.dqb_isoftlimit &&
1288             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1289             dquot->dq_dqb.dqb_itime &&
1290             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
1291             !ignore_hardlimit(dquot)) {
1292                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1293                 return -EDQUOT;
1294         }
1295
1296         if (dquot->dq_dqb.dqb_isoftlimit &&
1297             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1298             dquot->dq_dqb.dqb_itime == 0) {
1299                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
1300                 dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
1301                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
1302         }
1303
1304         return 0;
1305 }
1306
1307 /* needs dq_data_lock */
1308 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc,
1309                      struct dquot_warn *warn)
1310 {
1311         qsize_t tspace;
1312         struct super_block *sb = dquot->dq_sb;
1313
1314         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1315             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1316                 return 0;
1317
1318         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1319                 + space;
1320
1321         if (dquot->dq_dqb.dqb_bhardlimit &&
1322             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1323             !ignore_hardlimit(dquot)) {
1324                 if (!prealloc)
1325                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1326                 return -EDQUOT;
1327         }
1328
1329         if (dquot->dq_dqb.dqb_bsoftlimit &&
1330             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1331             dquot->dq_dqb.dqb_btime &&
1332             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
1333             !ignore_hardlimit(dquot)) {
1334                 if (!prealloc)
1335                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1336                 return -EDQUOT;
1337         }
1338
1339         if (dquot->dq_dqb.dqb_bsoftlimit &&
1340             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1341             dquot->dq_dqb.dqb_btime == 0) {
1342                 if (!prealloc) {
1343                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1344                         dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
1345                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1346                 }
1347                 else
1348                         /*
1349                          * We don't allow preallocation to exceed softlimit so exceeding will
1350                          * be always printed
1351                          */
1352                         return -EDQUOT;
1353         }
1354
1355         return 0;
1356 }
1357
1358 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1359 {
1360         qsize_t newinodes;
1361
1362         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1363             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1364             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1365                 return QUOTA_NL_NOWARN;
1366
1367         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1368         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1369                 return QUOTA_NL_ISOFTBELOW;
1370         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1371             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1372                 return QUOTA_NL_IHARDBELOW;
1373         return QUOTA_NL_NOWARN;
1374 }
1375
1376 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1377 {
1378         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1379             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1380                 return QUOTA_NL_NOWARN;
1381
1382         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1383                 return QUOTA_NL_BSOFTBELOW;
1384         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1385             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1386                 return QUOTA_NL_BHARDBELOW;
1387         return QUOTA_NL_NOWARN;
1388 }
1389
1390 static int dquot_active(const struct inode *inode)
1391 {
1392         struct super_block *sb = inode->i_sb;
1393
1394         if (IS_NOQUOTA(inode))
1395                 return 0;
1396         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1397 }
1398
1399 /*
1400  * Initialize quota pointers in inode
1401  *
1402  * It is better to call this function outside of any transaction as it
1403  * might need a lot of space in journal for dquot structure allocation.
1404  */
1405 static int __dquot_initialize(struct inode *inode, int type)
1406 {
1407         int cnt, init_needed = 0;
1408         struct dquot **dquots, *got[MAXQUOTAS] = {};
1409         struct super_block *sb = inode->i_sb;
1410         qsize_t rsv;
1411         int ret = 0;
1412
1413         if (!dquot_active(inode))
1414                 return 0;
1415
1416         dquots = i_dquot(inode);
1417
1418         /* First get references to structures we might need. */
1419         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1420                 struct kqid qid;
1421                 kprojid_t projid;
1422                 int rc;
1423                 struct dquot *dquot;
1424
1425                 if (type != -1 && cnt != type)
1426                         continue;
1427                 /*
1428                  * The i_dquot should have been initialized in most cases,
1429                  * we check it without locking here to avoid unnecessary
1430                  * dqget()/dqput() calls.
1431                  */
1432                 if (dquots[cnt])
1433                         continue;
1434
1435                 if (!sb_has_quota_active(sb, cnt))
1436                         continue;
1437
1438                 init_needed = 1;
1439
1440                 switch (cnt) {
1441                 case USRQUOTA:
1442                         qid = make_kqid_uid(inode->i_uid);
1443                         break;
1444                 case GRPQUOTA:
1445                         qid = make_kqid_gid(inode->i_gid);
1446                         break;
1447                 case PRJQUOTA:
1448                         rc = inode->i_sb->dq_op->get_projid(inode, &projid);
1449                         if (rc)
1450                                 continue;
1451                         qid = make_kqid_projid(projid);
1452                         break;
1453                 }
1454                 dquot = dqget(sb, qid);
1455                 if (IS_ERR(dquot)) {
1456                         /* We raced with somebody turning quotas off... */
1457                         if (PTR_ERR(dquot) != -ESRCH) {
1458                                 ret = PTR_ERR(dquot);
1459                                 goto out_put;
1460                         }
1461                         dquot = NULL;
1462                 }
1463                 got[cnt] = dquot;
1464         }
1465
1466         /* All required i_dquot has been initialized */
1467         if (!init_needed)
1468                 return 0;
1469
1470         spin_lock(&dq_data_lock);
1471         if (IS_NOQUOTA(inode))
1472                 goto out_lock;
1473         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1474                 if (type != -1 && cnt != type)
1475                         continue;
1476                 /* Avoid races with quotaoff() */
1477                 if (!sb_has_quota_active(sb, cnt))
1478                         continue;
1479                 /* We could race with quotaon or dqget() could have failed */
1480                 if (!got[cnt])
1481                         continue;
1482                 if (!dquots[cnt]) {
1483                         dquots[cnt] = got[cnt];
1484                         got[cnt] = NULL;
1485                         /*
1486                          * Make quota reservation system happy if someone
1487                          * did a write before quota was turned on
1488                          */
1489                         rsv = inode_get_rsv_space(inode);
1490                         if (unlikely(rsv))
1491                                 dquot_resv_space(dquots[cnt], rsv);
1492                 }
1493         }
1494 out_lock:
1495         spin_unlock(&dq_data_lock);
1496 out_put:
1497         /* Drop unused references */
1498         dqput_all(got);
1499
1500         return ret;
1501 }
1502
1503 int dquot_initialize(struct inode *inode)
1504 {
1505         return __dquot_initialize(inode, -1);
1506 }
1507 EXPORT_SYMBOL(dquot_initialize);
1508
1509 bool dquot_initialize_needed(struct inode *inode)
1510 {
1511         struct dquot **dquots;
1512         int i;
1513
1514         if (!dquot_active(inode))
1515                 return false;
1516
1517         dquots = i_dquot(inode);
1518         for (i = 0; i < MAXQUOTAS; i++)
1519                 if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
1520                         return true;
1521         return false;
1522 }
1523 EXPORT_SYMBOL(dquot_initialize_needed);
1524
1525 /*
1526  * Release all quotas referenced by inode.
1527  *
1528  * This function only be called on inode free or converting
1529  * a file to quota file, no other users for the i_dquot in
1530  * both cases, so we needn't call synchronize_srcu() after
1531  * clearing i_dquot.
1532  */
1533 static void __dquot_drop(struct inode *inode)
1534 {
1535         int cnt;
1536         struct dquot **dquots = i_dquot(inode);
1537         struct dquot *put[MAXQUOTAS];
1538
1539         spin_lock(&dq_data_lock);
1540         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1541                 put[cnt] = dquots[cnt];
1542                 dquots[cnt] = NULL;
1543         }
1544         spin_unlock(&dq_data_lock);
1545         dqput_all(put);
1546 }
1547
1548 void dquot_drop(struct inode *inode)
1549 {
1550         struct dquot * const *dquots;
1551         int cnt;
1552
1553         if (IS_NOQUOTA(inode))
1554                 return;
1555
1556         /*
1557          * Test before calling to rule out calls from proc and such
1558          * where we are not allowed to block. Note that this is
1559          * actually reliable test even without the lock - the caller
1560          * must assure that nobody can come after the DQUOT_DROP and
1561          * add quota pointers back anyway.
1562          */
1563         dquots = i_dquot(inode);
1564         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1565                 if (dquots[cnt])
1566                         break;
1567         }
1568
1569         if (cnt < MAXQUOTAS)
1570                 __dquot_drop(inode);
1571 }
1572 EXPORT_SYMBOL(dquot_drop);
1573
1574 /*
1575  * inode_reserved_space is managed internally by quota, and protected by
1576  * i_lock similar to i_blocks+i_bytes.
1577  */
1578 static qsize_t *inode_reserved_space(struct inode * inode)
1579 {
1580         /* Filesystem must explicitly define it's own method in order to use
1581          * quota reservation interface */
1582         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1583         return inode->i_sb->dq_op->get_reserved_space(inode);
1584 }
1585
1586 void inode_add_rsv_space(struct inode *inode, qsize_t number)
1587 {
1588         spin_lock(&inode->i_lock);
1589         *inode_reserved_space(inode) += number;
1590         spin_unlock(&inode->i_lock);
1591 }
1592 EXPORT_SYMBOL(inode_add_rsv_space);
1593
1594 void inode_claim_rsv_space(struct inode *inode, qsize_t number)
1595 {
1596         spin_lock(&inode->i_lock);
1597         *inode_reserved_space(inode) -= number;
1598         __inode_add_bytes(inode, number);
1599         spin_unlock(&inode->i_lock);
1600 }
1601 EXPORT_SYMBOL(inode_claim_rsv_space);
1602
1603 void inode_reclaim_rsv_space(struct inode *inode, qsize_t number)
1604 {
1605         spin_lock(&inode->i_lock);
1606         *inode_reserved_space(inode) += number;
1607         __inode_sub_bytes(inode, number);
1608         spin_unlock(&inode->i_lock);
1609 }
1610 EXPORT_SYMBOL(inode_reclaim_rsv_space);
1611
1612 void inode_sub_rsv_space(struct inode *inode, qsize_t number)
1613 {
1614         spin_lock(&inode->i_lock);
1615         *inode_reserved_space(inode) -= number;
1616         spin_unlock(&inode->i_lock);
1617 }
1618 EXPORT_SYMBOL(inode_sub_rsv_space);
1619
1620 static qsize_t inode_get_rsv_space(struct inode *inode)
1621 {
1622         qsize_t ret;
1623
1624         if (!inode->i_sb->dq_op->get_reserved_space)
1625                 return 0;
1626         spin_lock(&inode->i_lock);
1627         ret = *inode_reserved_space(inode);
1628         spin_unlock(&inode->i_lock);
1629         return ret;
1630 }
1631
1632 static void inode_incr_space(struct inode *inode, qsize_t number,
1633                                 int reserve)
1634 {
1635         if (reserve)
1636                 inode_add_rsv_space(inode, number);
1637         else
1638                 inode_add_bytes(inode, number);
1639 }
1640
1641 static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
1642 {
1643         if (reserve)
1644                 inode_sub_rsv_space(inode, number);
1645         else
1646                 inode_sub_bytes(inode, number);
1647 }
1648
1649 /*
1650  * This functions updates i_blocks+i_bytes fields and quota information
1651  * (together with appropriate checks).
1652  *
1653  * NOTE: We absolutely rely on the fact that caller dirties the inode
1654  * (usually helpers in quotaops.h care about this) and holds a handle for
1655  * the current transaction so that dquot write and inode write go into the
1656  * same transaction.
1657  */
1658
1659 /*
1660  * This operation can block, but only after everything is updated
1661  */
1662 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1663 {
1664         int cnt, ret = 0, index;
1665         struct dquot_warn warn[MAXQUOTAS];
1666         int reserve = flags & DQUOT_SPACE_RESERVE;
1667         struct dquot **dquots;
1668
1669         if (!dquot_active(inode)) {
1670                 inode_incr_space(inode, number, reserve);
1671                 goto out;
1672         }
1673
1674         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1675                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1676
1677         dquots = i_dquot(inode);
1678         index = srcu_read_lock(&dquot_srcu);
1679         spin_lock(&dq_data_lock);
1680         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1681                 if (!dquots[cnt])
1682                         continue;
1683                 ret = check_bdq(dquots[cnt], number,
1684                                 !(flags & DQUOT_SPACE_WARN), &warn[cnt]);
1685                 if (ret && !(flags & DQUOT_SPACE_NOFAIL)) {
1686                         spin_unlock(&dq_data_lock);
1687                         goto out_flush_warn;
1688                 }
1689         }
1690         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1691                 if (!dquots[cnt])
1692                         continue;
1693                 if (reserve)
1694                         dquot_resv_space(dquots[cnt], number);
1695                 else
1696                         dquot_incr_space(dquots[cnt], number);
1697         }
1698         inode_incr_space(inode, number, reserve);
1699         spin_unlock(&dq_data_lock);
1700
1701         if (reserve)
1702                 goto out_flush_warn;
1703         mark_all_dquot_dirty(dquots);
1704 out_flush_warn:
1705         srcu_read_unlock(&dquot_srcu, index);
1706         flush_warnings(warn);
1707 out:
1708         return ret;
1709 }
1710 EXPORT_SYMBOL(__dquot_alloc_space);
1711
1712 /*
1713  * This operation can block, but only after everything is updated
1714  */
1715 int dquot_alloc_inode(struct inode *inode)
1716 {
1717         int cnt, ret = 0, index;
1718         struct dquot_warn warn[MAXQUOTAS];
1719         struct dquot * const *dquots;
1720
1721         if (!dquot_active(inode))
1722                 return 0;
1723         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1724                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1725
1726         dquots = i_dquot(inode);
1727         index = srcu_read_lock(&dquot_srcu);
1728         spin_lock(&dq_data_lock);
1729         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1730                 if (!dquots[cnt])
1731                         continue;
1732                 ret = check_idq(dquots[cnt], 1, &warn[cnt]);
1733                 if (ret)
1734                         goto warn_put_all;
1735         }
1736
1737         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1738                 if (!dquots[cnt])
1739                         continue;
1740                 dquot_incr_inodes(dquots[cnt], 1);
1741         }
1742
1743 warn_put_all:
1744         spin_unlock(&dq_data_lock);
1745         if (ret == 0)
1746                 mark_all_dquot_dirty(dquots);
1747         srcu_read_unlock(&dquot_srcu, index);
1748         flush_warnings(warn);
1749         return ret;
1750 }
1751 EXPORT_SYMBOL(dquot_alloc_inode);
1752
1753 /*
1754  * Convert in-memory reserved quotas to real consumed quotas
1755  */
1756 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1757 {
1758         struct dquot **dquots;
1759         int cnt, index;
1760
1761         if (!dquot_active(inode)) {
1762                 inode_claim_rsv_space(inode, number);
1763                 return 0;
1764         }
1765
1766         dquots = i_dquot(inode);
1767         index = srcu_read_lock(&dquot_srcu);
1768         spin_lock(&dq_data_lock);
1769         /* Claim reserved quotas to allocated quotas */
1770         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1771                 if (dquots[cnt])
1772                         dquot_claim_reserved_space(dquots[cnt], number);
1773         }
1774         /* Update inode bytes */
1775         inode_claim_rsv_space(inode, number);
1776         spin_unlock(&dq_data_lock);
1777         mark_all_dquot_dirty(dquots);
1778         srcu_read_unlock(&dquot_srcu, index);
1779         return 0;
1780 }
1781 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1782
1783 /*
1784  * Convert allocated space back to in-memory reserved quotas
1785  */
1786 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1787 {
1788         struct dquot **dquots;
1789         int cnt, index;
1790
1791         if (!dquot_active(inode)) {
1792                 inode_reclaim_rsv_space(inode, number);
1793                 return;
1794         }
1795
1796         dquots = i_dquot(inode);
1797         index = srcu_read_lock(&dquot_srcu);
1798         spin_lock(&dq_data_lock);
1799         /* Claim reserved quotas to allocated quotas */
1800         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1801                 if (dquots[cnt])
1802                         dquot_reclaim_reserved_space(dquots[cnt], number);
1803         }
1804         /* Update inode bytes */
1805         inode_reclaim_rsv_space(inode, number);
1806         spin_unlock(&dq_data_lock);
1807         mark_all_dquot_dirty(dquots);
1808         srcu_read_unlock(&dquot_srcu, index);
1809         return;
1810 }
1811 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1812
1813 /*
1814  * This operation can block, but only after everything is updated
1815  */
1816 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1817 {
1818         unsigned int cnt;
1819         struct dquot_warn warn[MAXQUOTAS];
1820         struct dquot **dquots;
1821         int reserve = flags & DQUOT_SPACE_RESERVE, index;
1822
1823         if (!dquot_active(inode)) {
1824                 inode_decr_space(inode, number, reserve);
1825                 return;
1826         }
1827
1828         dquots = i_dquot(inode);
1829         index = srcu_read_lock(&dquot_srcu);
1830         spin_lock(&dq_data_lock);
1831         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1832                 int wtype;
1833
1834                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1835                 if (!dquots[cnt])
1836                         continue;
1837                 wtype = info_bdq_free(dquots[cnt], number);
1838                 if (wtype != QUOTA_NL_NOWARN)
1839                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1840                 if (reserve)
1841                         dquot_free_reserved_space(dquots[cnt], number);
1842                 else
1843                         dquot_decr_space(dquots[cnt], number);
1844         }
1845         inode_decr_space(inode, number, reserve);
1846         spin_unlock(&dq_data_lock);
1847
1848         if (reserve)
1849                 goto out_unlock;
1850         mark_all_dquot_dirty(dquots);
1851 out_unlock:
1852         srcu_read_unlock(&dquot_srcu, index);
1853         flush_warnings(warn);
1854 }
1855 EXPORT_SYMBOL(__dquot_free_space);
1856
1857 /*
1858  * This operation can block, but only after everything is updated
1859  */
1860 void dquot_free_inode(struct inode *inode)
1861 {
1862         unsigned int cnt;
1863         struct dquot_warn warn[MAXQUOTAS];
1864         struct dquot * const *dquots;
1865         int index;
1866
1867         if (!dquot_active(inode))
1868                 return;
1869
1870         dquots = i_dquot(inode);
1871         index = srcu_read_lock(&dquot_srcu);
1872         spin_lock(&dq_data_lock);
1873         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1874                 int wtype;
1875
1876                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1877                 if (!dquots[cnt])
1878                         continue;
1879                 wtype = info_idq_free(dquots[cnt], 1);
1880                 if (wtype != QUOTA_NL_NOWARN)
1881                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1882                 dquot_decr_inodes(dquots[cnt], 1);
1883         }
1884         spin_unlock(&dq_data_lock);
1885         mark_all_dquot_dirty(dquots);
1886         srcu_read_unlock(&dquot_srcu, index);
1887         flush_warnings(warn);
1888 }
1889 EXPORT_SYMBOL(dquot_free_inode);
1890
1891 /*
1892  * Transfer the number of inode and blocks from one diskquota to an other.
1893  * On success, dquot references in transfer_to are consumed and references
1894  * to original dquots that need to be released are placed there. On failure,
1895  * references are kept untouched.
1896  *
1897  * This operation can block, but only after everything is updated
1898  * A transaction must be started when entering this function.
1899  *
1900  * We are holding reference on transfer_from & transfer_to, no need to
1901  * protect them by srcu_read_lock().
1902  */
1903 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1904 {
1905         qsize_t space, cur_space;
1906         qsize_t rsv_space = 0;
1907         qsize_t inode_usage = 1;
1908         struct dquot *transfer_from[MAXQUOTAS] = {};
1909         int cnt, ret = 0;
1910         char is_valid[MAXQUOTAS] = {};
1911         struct dquot_warn warn_to[MAXQUOTAS];
1912         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1913         struct dquot_warn warn_from_space[MAXQUOTAS];
1914
1915         if (IS_NOQUOTA(inode))
1916                 return 0;
1917
1918         if (inode->i_sb->dq_op->get_inode_usage) {
1919                 ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
1920                 if (ret)
1921                         return ret;
1922         }
1923
1924         /* Initialize the arrays */
1925         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1926                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
1927                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
1928                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
1929         }
1930
1931         spin_lock(&dq_data_lock);
1932         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1933                 spin_unlock(&dq_data_lock);
1934                 return 0;
1935         }
1936         cur_space = inode_get_bytes(inode);
1937         rsv_space = inode_get_rsv_space(inode);
1938         space = cur_space + rsv_space;
1939         /* Build the transfer_from list and check the limits */
1940         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1941                 /*
1942                  * Skip changes for same uid or gid or for turned off quota-type.
1943                  */
1944                 if (!transfer_to[cnt])
1945                         continue;
1946                 /* Avoid races with quotaoff() */
1947                 if (!sb_has_quota_active(inode->i_sb, cnt))
1948                         continue;
1949                 is_valid[cnt] = 1;
1950                 transfer_from[cnt] = i_dquot(inode)[cnt];
1951                 ret = check_idq(transfer_to[cnt], inode_usage, &warn_to[cnt]);
1952                 if (ret)
1953                         goto over_quota;
1954                 ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
1955                 if (ret)
1956                         goto over_quota;
1957         }
1958
1959         /*
1960          * Finally perform the needed transfer from transfer_from to transfer_to
1961          */
1962         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1963                 if (!is_valid[cnt])
1964                         continue;
1965                 /* Due to IO error we might not have transfer_from[] structure */
1966                 if (transfer_from[cnt]) {
1967                         int wtype;
1968                         wtype = info_idq_free(transfer_from[cnt], inode_usage);
1969                         if (wtype != QUOTA_NL_NOWARN)
1970                                 prepare_warning(&warn_from_inodes[cnt],
1971                                                 transfer_from[cnt], wtype);
1972                         wtype = info_bdq_free(transfer_from[cnt], space);
1973                         if (wtype != QUOTA_NL_NOWARN)
1974                                 prepare_warning(&warn_from_space[cnt],
1975                                                 transfer_from[cnt], wtype);
1976                         dquot_decr_inodes(transfer_from[cnt], inode_usage);
1977                         dquot_decr_space(transfer_from[cnt], cur_space);
1978                         dquot_free_reserved_space(transfer_from[cnt],
1979                                                   rsv_space);
1980                 }
1981
1982                 dquot_incr_inodes(transfer_to[cnt], inode_usage);
1983                 dquot_incr_space(transfer_to[cnt], cur_space);
1984                 dquot_resv_space(transfer_to[cnt], rsv_space);
1985
1986                 i_dquot(inode)[cnt] = transfer_to[cnt];
1987         }
1988         spin_unlock(&dq_data_lock);
1989
1990         mark_all_dquot_dirty(transfer_from);
1991         mark_all_dquot_dirty(transfer_to);
1992         flush_warnings(warn_to);
1993         flush_warnings(warn_from_inodes);
1994         flush_warnings(warn_from_space);
1995         /* Pass back references to put */
1996         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1997                 if (is_valid[cnt])
1998                         transfer_to[cnt] = transfer_from[cnt];
1999         return 0;
2000 over_quota:
2001         spin_unlock(&dq_data_lock);
2002         flush_warnings(warn_to);
2003         return ret;
2004 }
2005 EXPORT_SYMBOL(__dquot_transfer);
2006
2007 /* Wrapper for transferring ownership of an inode for uid/gid only
2008  * Called from FSXXX_setattr()
2009  */
2010 int dquot_transfer(struct inode *inode, struct iattr *iattr)
2011 {
2012         struct dquot *transfer_to[MAXQUOTAS] = {};
2013         struct dquot *dquot;
2014         struct super_block *sb = inode->i_sb;
2015         int ret;
2016
2017         if (!dquot_active(inode))
2018                 return 0;
2019
2020         if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
2021                 dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
2022                 if (IS_ERR(dquot)) {
2023                         if (PTR_ERR(dquot) != -ESRCH) {
2024                                 ret = PTR_ERR(dquot);
2025                                 goto out_put;
2026                         }
2027                         dquot = NULL;
2028                 }
2029                 transfer_to[USRQUOTA] = dquot;
2030         }
2031         if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
2032                 dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
2033                 if (IS_ERR(dquot)) {
2034                         if (PTR_ERR(dquot) != -ESRCH) {
2035                                 ret = PTR_ERR(dquot);
2036                                 goto out_put;
2037                         }
2038                         dquot = NULL;
2039                 }
2040                 transfer_to[GRPQUOTA] = dquot;
2041         }
2042         ret = __dquot_transfer(inode, transfer_to);
2043 out_put:
2044         dqput_all(transfer_to);
2045         return ret;
2046 }
2047 EXPORT_SYMBOL(dquot_transfer);
2048
2049 /*
2050  * Write info of quota file to disk
2051  */
2052 int dquot_commit_info(struct super_block *sb, int type)
2053 {
2054         struct quota_info *dqopt = sb_dqopt(sb);
2055
2056         return dqopt->ops[type]->write_file_info(sb, type);
2057 }
2058 EXPORT_SYMBOL(dquot_commit_info);
2059
2060 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
2061 {
2062         struct quota_info *dqopt = sb_dqopt(sb);
2063
2064         if (!sb_has_quota_active(sb, qid->type))
2065                 return -ESRCH;
2066         if (!dqopt->ops[qid->type]->get_next_id)
2067                 return -ENOSYS;
2068         return dqopt->ops[qid->type]->get_next_id(sb, qid);
2069 }
2070 EXPORT_SYMBOL(dquot_get_next_id);
2071
2072 /*
2073  * Definitions of diskquota operations.
2074  */
2075 const struct dquot_operations dquot_operations = {
2076         .write_dquot    = dquot_commit,
2077         .acquire_dquot  = dquot_acquire,
2078         .release_dquot  = dquot_release,
2079         .mark_dirty     = dquot_mark_dquot_dirty,
2080         .write_info     = dquot_commit_info,
2081         .alloc_dquot    = dquot_alloc,
2082         .destroy_dquot  = dquot_destroy,
2083         .get_next_id    = dquot_get_next_id,
2084 };
2085 EXPORT_SYMBOL(dquot_operations);
2086
2087 /*
2088  * Generic helper for ->open on filesystems supporting disk quotas.
2089  */
2090 int dquot_file_open(struct inode *inode, struct file *file)
2091 {
2092         int error;
2093
2094         error = generic_file_open(inode, file);
2095         if (!error && (file->f_mode & FMODE_WRITE))
2096                 dquot_initialize(inode);
2097         return error;
2098 }
2099 EXPORT_SYMBOL(dquot_file_open);
2100
2101 /*
2102  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2103  */
2104 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2105 {
2106         int cnt, ret = 0;
2107         struct quota_info *dqopt = sb_dqopt(sb);
2108         struct inode *toputinode[MAXQUOTAS];
2109
2110         /* s_umount should be held in exclusive mode */
2111         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2112                 up_read(&sb->s_umount);
2113
2114         /* Cannot turn off usage accounting without turning off limits, or
2115          * suspend quotas and simultaneously turn quotas off. */
2116         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2117             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2118             DQUOT_USAGE_ENABLED)))
2119                 return -EINVAL;
2120
2121         /*
2122          * Skip everything if there's nothing to do. We have to do this because
2123          * sometimes we are called when fill_super() failed and calling
2124          * sync_fs() in such cases does no good.
2125          */
2126         if (!sb_any_quota_loaded(sb))
2127                 return 0;
2128
2129         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2130                 toputinode[cnt] = NULL;
2131                 if (type != -1 && cnt != type)
2132                         continue;
2133                 if (!sb_has_quota_loaded(sb, cnt))
2134                         continue;
2135
2136                 if (flags & DQUOT_SUSPENDED) {
2137                         spin_lock(&dq_state_lock);
2138                         dqopt->flags |=
2139                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2140                         spin_unlock(&dq_state_lock);
2141                 } else {
2142                         spin_lock(&dq_state_lock);
2143                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2144                         /* Turning off suspended quotas? */
2145                         if (!sb_has_quota_loaded(sb, cnt) &&
2146                             sb_has_quota_suspended(sb, cnt)) {
2147                                 dqopt->flags &= ~dquot_state_flag(
2148                                                         DQUOT_SUSPENDED, cnt);
2149                                 spin_unlock(&dq_state_lock);
2150                                 iput(dqopt->files[cnt]);
2151                                 dqopt->files[cnt] = NULL;
2152                                 continue;
2153                         }
2154                         spin_unlock(&dq_state_lock);
2155                 }
2156
2157                 /* We still have to keep quota loaded? */
2158                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2159                         continue;
2160
2161                 /* Note: these are blocking operations */
2162                 drop_dquot_ref(sb, cnt);
2163                 invalidate_dquots(sb, cnt);
2164                 /*
2165                  * Now all dquots should be invalidated, all writes done so we
2166                  * should be only users of the info. No locks needed.
2167                  */
2168                 if (info_dirty(&dqopt->info[cnt]))
2169                         sb->dq_op->write_info(sb, cnt);
2170                 if (dqopt->ops[cnt]->free_file_info)
2171                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2172                 put_quota_format(dqopt->info[cnt].dqi_format);
2173
2174                 toputinode[cnt] = dqopt->files[cnt];
2175                 if (!sb_has_quota_loaded(sb, cnt))
2176                         dqopt->files[cnt] = NULL;
2177                 dqopt->info[cnt].dqi_flags = 0;
2178                 dqopt->info[cnt].dqi_igrace = 0;
2179                 dqopt->info[cnt].dqi_bgrace = 0;
2180                 dqopt->ops[cnt] = NULL;
2181         }
2182
2183         /* Skip syncing and setting flags if quota files are hidden */
2184         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2185                 goto put_inodes;
2186
2187         /* Sync the superblock so that buffers with quota data are written to
2188          * disk (and so userspace sees correct data afterwards). */
2189         if (sb->s_op->sync_fs)
2190                 sb->s_op->sync_fs(sb, 1);
2191         sync_blockdev(sb->s_bdev);
2192         /* Now the quota files are just ordinary files and we can set the
2193          * inode flags back. Moreover we discard the pagecache so that
2194          * userspace sees the writes we did bypassing the pagecache. We
2195          * must also discard the blockdev buffers so that we see the
2196          * changes done by userspace on the next quotaon() */
2197         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2198                 /* This can happen when suspending quotas on remount-ro... */
2199                 if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {
2200                         inode_lock(toputinode[cnt]);
2201                         toputinode[cnt]->i_flags &= ~S_NOQUOTA;
2202                         truncate_inode_pages(&toputinode[cnt]->i_data, 0);
2203                         inode_unlock(toputinode[cnt]);
2204                         mark_inode_dirty_sync(toputinode[cnt]);
2205                 }
2206         if (sb->s_bdev)
2207                 invalidate_bdev(sb->s_bdev);
2208 put_inodes:
2209         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2210                 if (toputinode[cnt]) {
2211                         /* On remount RO, we keep the inode pointer so that we
2212                          * can reenable quota on the subsequent remount RW. We
2213                          * have to check 'flags' variable and not use sb_has_
2214                          * function because another quotaon / quotaoff could
2215                          * change global state before we got here. We refuse
2216                          * to suspend quotas when there is pending delete on
2217                          * the quota file... */
2218                         if (!(flags & DQUOT_SUSPENDED))
2219                                 iput(toputinode[cnt]);
2220                         else if (!toputinode[cnt]->i_nlink)
2221                                 ret = -EBUSY;
2222                 }
2223         return ret;
2224 }
2225 EXPORT_SYMBOL(dquot_disable);
2226
2227 int dquot_quota_off(struct super_block *sb, int type)
2228 {
2229         return dquot_disable(sb, type,
2230                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2231 }
2232 EXPORT_SYMBOL(dquot_quota_off);
2233
2234 /*
2235  *      Turn quotas on on a device
2236  */
2237
2238 /*
2239  * Helper function to turn quotas on when we already have the inode of
2240  * quota file and no quota information is loaded.
2241  */
2242 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
2243         unsigned int flags)
2244 {
2245         struct quota_format_type *fmt = find_quota_format(format_id);
2246         struct super_block *sb = inode->i_sb;
2247         struct quota_info *dqopt = sb_dqopt(sb);
2248         int error;
2249
2250         if (!fmt)
2251                 return -ESRCH;
2252         if (!S_ISREG(inode->i_mode)) {
2253                 error = -EACCES;
2254                 goto out_fmt;
2255         }
2256         if (IS_RDONLY(inode)) {
2257                 error = -EROFS;
2258                 goto out_fmt;
2259         }
2260         if (!sb->s_op->quota_write || !sb->s_op->quota_read ||
2261             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2262                 error = -EINVAL;
2263                 goto out_fmt;
2264         }
2265         /* Filesystems outside of init_user_ns not yet supported */
2266         if (sb->s_user_ns != &init_user_ns) {
2267                 error = -EINVAL;
2268                 goto out_fmt;
2269         }
2270         /* Usage always has to be set... */
2271         if (!(flags & DQUOT_USAGE_ENABLED)) {
2272                 error = -EINVAL;
2273                 goto out_fmt;
2274         }
2275         if (sb_has_quota_loaded(sb, type)) {
2276                 error = -EBUSY;
2277                 goto out_fmt;
2278         }
2279
2280         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2281                 /* As we bypass the pagecache we must now flush all the
2282                  * dirty data and invalidate caches so that kernel sees
2283                  * changes from userspace. It is not enough to just flush
2284                  * the quota file since if blocksize < pagesize, invalidation
2285                  * of the cache could fail because of other unrelated dirty
2286                  * data */
2287                 sync_filesystem(sb);
2288                 invalidate_bdev(sb->s_bdev);
2289         }
2290
2291         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2292                 /* We don't want quota and atime on quota files (deadlocks
2293                  * possible) Also nobody should write to the file - we use
2294                  * special IO operations which ignore the immutable bit. */
2295                 inode_lock(inode);
2296                 inode->i_flags |= S_NOQUOTA;
2297                 inode_unlock(inode);
2298                 /*
2299                  * When S_NOQUOTA is set, remove dquot references as no more
2300                  * references can be added
2301                  */
2302                 __dquot_drop(inode);
2303         }
2304
2305         error = -EIO;
2306         dqopt->files[type] = igrab(inode);
2307         if (!dqopt->files[type])
2308                 goto out_file_flags;
2309         error = -EINVAL;
2310         if (!fmt->qf_ops->check_quota_file(sb, type))
2311                 goto out_file_init;
2312
2313         dqopt->ops[type] = fmt->qf_ops;
2314         dqopt->info[type].dqi_format = fmt;
2315         dqopt->info[type].dqi_fmt_id = format_id;
2316         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2317         error = dqopt->ops[type]->read_file_info(sb, type);
2318         if (error < 0)
2319                 goto out_file_init;
2320         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2321                 spin_lock(&dq_data_lock);
2322                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2323                 spin_unlock(&dq_data_lock);
2324         }
2325         spin_lock(&dq_state_lock);
2326         dqopt->flags |= dquot_state_flag(flags, type);
2327         spin_unlock(&dq_state_lock);
2328
2329         add_dquot_ref(sb, type);
2330
2331         return 0;
2332
2333 out_file_init:
2334         dqopt->files[type] = NULL;
2335         iput(inode);
2336 out_file_flags:
2337         inode_lock(inode);
2338         inode->i_flags &= ~S_NOQUOTA;
2339         inode_unlock(inode);
2340 out_fmt:
2341         put_quota_format(fmt);
2342
2343         return error; 
2344 }
2345
2346 /* Reenable quotas on remount RW */
2347 int dquot_resume(struct super_block *sb, int type)
2348 {
2349         struct quota_info *dqopt = sb_dqopt(sb);
2350         struct inode *inode;
2351         int ret = 0, cnt;
2352         unsigned int flags;
2353
2354         /* s_umount should be held in exclusive mode */
2355         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2356                 up_read(&sb->s_umount);
2357
2358         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2359                 if (type != -1 && cnt != type)
2360                         continue;
2361                 if (!sb_has_quota_suspended(sb, cnt))
2362                         continue;
2363
2364                 inode = dqopt->files[cnt];
2365                 dqopt->files[cnt] = NULL;
2366                 spin_lock(&dq_state_lock);
2367                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2368                                                         DQUOT_LIMITS_ENABLED,
2369                                                         cnt);
2370                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2371                 spin_unlock(&dq_state_lock);
2372
2373                 flags = dquot_generic_flag(flags, cnt);
2374                 ret = vfs_load_quota_inode(inode, cnt,
2375                                 dqopt->info[cnt].dqi_fmt_id, flags);
2376                 iput(inode);
2377         }
2378
2379         return ret;
2380 }
2381 EXPORT_SYMBOL(dquot_resume);
2382
2383 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2384                    const struct path *path)
2385 {
2386         int error = security_quota_on(path->dentry);
2387         if (error)
2388                 return error;
2389         /* Quota file not on the same filesystem? */
2390         if (path->dentry->d_sb != sb)
2391                 error = -EXDEV;
2392         else
2393                 error = vfs_load_quota_inode(d_inode(path->dentry), type,
2394                                              format_id, DQUOT_USAGE_ENABLED |
2395                                              DQUOT_LIMITS_ENABLED);
2396         return error;
2397 }
2398 EXPORT_SYMBOL(dquot_quota_on);
2399
2400 /*
2401  * More powerful function for turning on quotas allowing setting
2402  * of individual quota flags
2403  */
2404 int dquot_enable(struct inode *inode, int type, int format_id,
2405                  unsigned int flags)
2406 {
2407         struct super_block *sb = inode->i_sb;
2408
2409         /* Just unsuspend quotas? */
2410         BUG_ON(flags & DQUOT_SUSPENDED);
2411         /* s_umount should be held in exclusive mode */
2412         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2413                 up_read(&sb->s_umount);
2414
2415         if (!flags)
2416                 return 0;
2417         /* Just updating flags needed? */
2418         if (sb_has_quota_loaded(sb, type)) {
2419                 if (flags & DQUOT_USAGE_ENABLED &&
2420                     sb_has_quota_usage_enabled(sb, type))
2421                         return -EBUSY;
2422                 if (flags & DQUOT_LIMITS_ENABLED &&
2423                     sb_has_quota_limits_enabled(sb, type))
2424                         return -EBUSY;
2425                 spin_lock(&dq_state_lock);
2426                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2427                 spin_unlock(&dq_state_lock);
2428                 return 0;
2429         }
2430
2431         return vfs_load_quota_inode(inode, type, format_id, flags);
2432 }
2433 EXPORT_SYMBOL(dquot_enable);
2434
2435 /*
2436  * This function is used when filesystem needs to initialize quotas
2437  * during mount time.
2438  */
2439 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2440                 int format_id, int type)
2441 {
2442         struct dentry *dentry;
2443         int error;
2444
2445         dentry = lookup_one_len_unlocked(qf_name, sb->s_root, strlen(qf_name));
2446         if (IS_ERR(dentry))
2447                 return PTR_ERR(dentry);
2448
2449         if (d_really_is_negative(dentry)) {
2450                 error = -ENOENT;
2451                 goto out;
2452         }
2453
2454         error = security_quota_on(dentry);
2455         if (!error)
2456                 error = vfs_load_quota_inode(d_inode(dentry), type, format_id,
2457                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2458
2459 out:
2460         dput(dentry);
2461         return error;
2462 }
2463 EXPORT_SYMBOL(dquot_quota_on_mount);
2464
2465 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2466 {
2467         int ret;
2468         int type;
2469         struct quota_info *dqopt = sb_dqopt(sb);
2470
2471         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2472                 return -ENOSYS;
2473         /* Accounting cannot be turned on while fs is mounted */
2474         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2475         if (!flags)
2476                 return -EINVAL;
2477         for (type = 0; type < MAXQUOTAS; type++) {
2478                 if (!(flags & qtype_enforce_flag(type)))
2479                         continue;
2480                 /* Can't enforce without accounting */
2481                 if (!sb_has_quota_usage_enabled(sb, type))
2482                         return -EINVAL;
2483                 ret = dquot_enable(dqopt->files[type], type,
2484                                    dqopt->info[type].dqi_fmt_id,
2485                                    DQUOT_LIMITS_ENABLED);
2486                 if (ret < 0)
2487                         goto out_err;
2488         }
2489         return 0;
2490 out_err:
2491         /* Backout enforcement enablement we already did */
2492         for (type--; type >= 0; type--)  {
2493                 if (flags & qtype_enforce_flag(type))
2494                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2495         }
2496         /* Error code translation for better compatibility with XFS */
2497         if (ret == -EBUSY)
2498                 ret = -EEXIST;
2499         return ret;
2500 }
2501
2502 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2503 {
2504         int ret;
2505         int type;
2506         struct quota_info *dqopt = sb_dqopt(sb);
2507
2508         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2509                 return -ENOSYS;
2510         /*
2511          * We don't support turning off accounting via quotactl. In principle
2512          * quota infrastructure can do this but filesystems don't expect
2513          * userspace to be able to do it.
2514          */
2515         if (flags &
2516                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2517                 return -EOPNOTSUPP;
2518
2519         /* Filter out limits not enabled */
2520         for (type = 0; type < MAXQUOTAS; type++)
2521                 if (!sb_has_quota_limits_enabled(sb, type))
2522                         flags &= ~qtype_enforce_flag(type);
2523         /* Nothing left? */
2524         if (!flags)
2525                 return -EEXIST;
2526         for (type = 0; type < MAXQUOTAS; type++) {
2527                 if (flags & qtype_enforce_flag(type)) {
2528                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2529                         if (ret < 0)
2530                                 goto out_err;
2531                 }
2532         }
2533         return 0;
2534 out_err:
2535         /* Backout enforcement disabling we already did */
2536         for (type--; type >= 0; type--)  {
2537                 if (flags & qtype_enforce_flag(type))
2538                         dquot_enable(dqopt->files[type], type,
2539                                      dqopt->info[type].dqi_fmt_id,
2540                                      DQUOT_LIMITS_ENABLED);
2541         }
2542         return ret;
2543 }
2544
2545 /* Generic routine for getting common part of quota structure */
2546 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2547 {
2548         struct mem_dqblk *dm = &dquot->dq_dqb;
2549
2550         memset(di, 0, sizeof(*di));
2551         spin_lock(&dq_data_lock);
2552         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2553         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2554         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2555         di->d_ino_softlimit = dm->dqb_isoftlimit;
2556         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2557         di->d_ino_count = dm->dqb_curinodes;
2558         di->d_spc_timer = dm->dqb_btime;
2559         di->d_ino_timer = dm->dqb_itime;
2560         spin_unlock(&dq_data_lock);
2561 }
2562
2563 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2564                     struct qc_dqblk *di)
2565 {
2566         struct dquot *dquot;
2567
2568         dquot = dqget(sb, qid);
2569         if (IS_ERR(dquot))
2570                 return PTR_ERR(dquot);
2571         do_get_dqblk(dquot, di);
2572         dqput(dquot);
2573
2574         return 0;
2575 }
2576 EXPORT_SYMBOL(dquot_get_dqblk);
2577
2578 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2579                          struct qc_dqblk *di)
2580 {
2581         struct dquot *dquot;
2582         int err;
2583
2584         if (!sb->dq_op->get_next_id)
2585                 return -ENOSYS;
2586         err = sb->dq_op->get_next_id(sb, qid);
2587         if (err < 0)
2588                 return err;
2589         dquot = dqget(sb, *qid);
2590         if (IS_ERR(dquot))
2591                 return PTR_ERR(dquot);
2592         do_get_dqblk(dquot, di);
2593         dqput(dquot);
2594
2595         return 0;
2596 }
2597 EXPORT_SYMBOL(dquot_get_next_dqblk);
2598
2599 #define VFS_QC_MASK \
2600         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2601          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2602          QC_SPC_TIMER | QC_INO_TIMER)
2603
2604 /* Generic routine for setting common part of quota structure */
2605 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2606 {
2607         struct mem_dqblk *dm = &dquot->dq_dqb;
2608         int check_blim = 0, check_ilim = 0;
2609         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2610
2611         if (di->d_fieldmask & ~VFS_QC_MASK)
2612                 return -EINVAL;
2613
2614         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2615              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2616             ((di->d_fieldmask & QC_SPC_HARD) &&
2617              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2618             ((di->d_fieldmask & QC_INO_SOFT) &&
2619              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2620             ((di->d_fieldmask & QC_INO_HARD) &&
2621              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2622                 return -ERANGE;
2623
2624         spin_lock(&dq_data_lock);
2625         if (di->d_fieldmask & QC_SPACE) {
2626                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2627                 check_blim = 1;
2628                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2629         }
2630
2631         if (di->d_fieldmask & QC_SPC_SOFT)
2632                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2633         if (di->d_fieldmask & QC_SPC_HARD)
2634                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2635         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2636                 check_blim = 1;
2637                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2638         }
2639
2640         if (di->d_fieldmask & QC_INO_COUNT) {
2641                 dm->dqb_curinodes = di->d_ino_count;
2642                 check_ilim = 1;
2643                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2644         }
2645
2646         if (di->d_fieldmask & QC_INO_SOFT)
2647                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2648         if (di->d_fieldmask & QC_INO_HARD)
2649                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2650         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2651                 check_ilim = 1;
2652                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2653         }
2654
2655         if (di->d_fieldmask & QC_SPC_TIMER) {
2656                 dm->dqb_btime = di->d_spc_timer;
2657                 check_blim = 1;
2658                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2659         }
2660
2661         if (di->d_fieldmask & QC_INO_TIMER) {
2662                 dm->dqb_itime = di->d_ino_timer;
2663                 check_ilim = 1;
2664                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2665         }
2666
2667         if (check_blim) {
2668                 if (!dm->dqb_bsoftlimit ||
2669                     dm->dqb_curspace < dm->dqb_bsoftlimit) {
2670                         dm->dqb_btime = 0;
2671                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2672                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2673                         /* Set grace only if user hasn't provided his own... */
2674                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2675         }
2676         if (check_ilim) {
2677                 if (!dm->dqb_isoftlimit ||
2678                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2679                         dm->dqb_itime = 0;
2680                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2681                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2682                         /* Set grace only if user hasn't provided his own... */
2683                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2684         }
2685         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2686             dm->dqb_isoftlimit)
2687                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2688         else
2689                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2690         spin_unlock(&dq_data_lock);
2691         mark_dquot_dirty(dquot);
2692
2693         return 0;
2694 }
2695
2696 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2697                   struct qc_dqblk *di)
2698 {
2699         struct dquot *dquot;
2700         int rc;
2701
2702         dquot = dqget(sb, qid);
2703         if (IS_ERR(dquot)) {
2704                 rc = PTR_ERR(dquot);
2705                 goto out;
2706         }
2707         rc = do_set_dqblk(dquot, di);
2708         dqput(dquot);
2709 out:
2710         return rc;
2711 }
2712 EXPORT_SYMBOL(dquot_set_dqblk);
2713
2714 /* Generic routine for getting common part of quota file information */
2715 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2716 {
2717         struct mem_dqinfo *mi;
2718         struct qc_type_state *tstate;
2719         struct quota_info *dqopt = sb_dqopt(sb);
2720         int type;
2721   
2722         memset(state, 0, sizeof(*state));
2723         for (type = 0; type < MAXQUOTAS; type++) {
2724                 if (!sb_has_quota_active(sb, type))
2725                         continue;
2726                 tstate = state->s_state + type;
2727                 mi = sb_dqopt(sb)->info + type;
2728                 tstate->flags = QCI_ACCT_ENABLED;
2729                 spin_lock(&dq_data_lock);
2730                 if (mi->dqi_flags & DQF_SYS_FILE)
2731                         tstate->flags |= QCI_SYSFILE;
2732                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2733                         tstate->flags |= QCI_ROOT_SQUASH;
2734                 if (sb_has_quota_limits_enabled(sb, type))
2735                         tstate->flags |= QCI_LIMITS_ENFORCED;
2736                 tstate->spc_timelimit = mi->dqi_bgrace;
2737                 tstate->ino_timelimit = mi->dqi_igrace;
2738                 tstate->ino = dqopt->files[type]->i_ino;
2739                 tstate->blocks = dqopt->files[type]->i_blocks;
2740                 tstate->nextents = 1;   /* We don't know... */
2741                 spin_unlock(&dq_data_lock);
2742         }
2743         return 0;
2744 }
2745 EXPORT_SYMBOL(dquot_get_state);
2746
2747 /* Generic routine for setting common part of quota file information */
2748 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2749 {
2750         struct mem_dqinfo *mi;
2751         int err = 0;
2752
2753         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2754             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2755                 return -EINVAL;
2756         if (!sb_has_quota_active(sb, type))
2757                 return -ESRCH;
2758         mi = sb_dqopt(sb)->info + type;
2759         if (ii->i_fieldmask & QC_FLAGS) {
2760                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2761                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2762                         return -EINVAL;
2763         }
2764         spin_lock(&dq_data_lock);
2765         if (ii->i_fieldmask & QC_SPC_TIMER)
2766                 mi->dqi_bgrace = ii->i_spc_timelimit;
2767         if (ii->i_fieldmask & QC_INO_TIMER)
2768                 mi->dqi_igrace = ii->i_ino_timelimit;
2769         if (ii->i_fieldmask & QC_FLAGS) {
2770                 if (ii->i_flags & QCI_ROOT_SQUASH)
2771                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2772                 else
2773                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2774         }
2775         spin_unlock(&dq_data_lock);
2776         mark_info_dirty(sb, type);
2777         /* Force write to disk */
2778         sb->dq_op->write_info(sb, type);
2779         return err;
2780 }
2781 EXPORT_SYMBOL(dquot_set_dqinfo);
2782
2783 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2784         .quota_enable   = dquot_quota_enable,
2785         .quota_disable  = dquot_quota_disable,
2786         .quota_sync     = dquot_quota_sync,
2787         .get_state      = dquot_get_state,
2788         .set_info       = dquot_set_dqinfo,
2789         .get_dqblk      = dquot_get_dqblk,
2790         .get_nextdqblk  = dquot_get_next_dqblk,
2791         .set_dqblk      = dquot_set_dqblk
2792 };
2793 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2794
2795 static int do_proc_dqstats(struct ctl_table *table, int write,
2796                      void __user *buffer, size_t *lenp, loff_t *ppos)
2797 {
2798         unsigned int type = (int *)table->data - dqstats.stat;
2799
2800         /* Update global table */
2801         dqstats.stat[type] =
2802                         percpu_counter_sum_positive(&dqstats.counter[type]);
2803         return proc_dointvec(table, write, buffer, lenp, ppos);
2804 }
2805
2806 static struct ctl_table fs_dqstats_table[] = {
2807         {
2808                 .procname       = "lookups",
2809                 .data           = &dqstats.stat[DQST_LOOKUPS],
2810                 .maxlen         = sizeof(int),
2811                 .mode           = 0444,
2812                 .proc_handler   = do_proc_dqstats,
2813         },
2814         {
2815                 .procname       = "drops",
2816                 .data           = &dqstats.stat[DQST_DROPS],
2817                 .maxlen         = sizeof(int),
2818                 .mode           = 0444,
2819                 .proc_handler   = do_proc_dqstats,
2820         },
2821         {
2822                 .procname       = "reads",
2823                 .data           = &dqstats.stat[DQST_READS],
2824                 .maxlen         = sizeof(int),
2825                 .mode           = 0444,
2826                 .proc_handler   = do_proc_dqstats,
2827         },
2828         {
2829                 .procname       = "writes",
2830                 .data           = &dqstats.stat[DQST_WRITES],
2831                 .maxlen         = sizeof(int),
2832                 .mode           = 0444,
2833                 .proc_handler   = do_proc_dqstats,
2834         },
2835         {
2836                 .procname       = "cache_hits",
2837                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2838                 .maxlen         = sizeof(int),
2839                 .mode           = 0444,
2840                 .proc_handler   = do_proc_dqstats,
2841         },
2842         {
2843                 .procname       = "allocated_dquots",
2844                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2845                 .maxlen         = sizeof(int),
2846                 .mode           = 0444,
2847                 .proc_handler   = do_proc_dqstats,
2848         },
2849         {
2850                 .procname       = "free_dquots",
2851                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2852                 .maxlen         = sizeof(int),
2853                 .mode           = 0444,
2854                 .proc_handler   = do_proc_dqstats,
2855         },
2856         {
2857                 .procname       = "syncs",
2858                 .data           = &dqstats.stat[DQST_SYNCS],
2859                 .maxlen         = sizeof(int),
2860                 .mode           = 0444,
2861                 .proc_handler   = do_proc_dqstats,
2862         },
2863 #ifdef CONFIG_PRINT_QUOTA_WARNING
2864         {
2865                 .procname       = "warnings",
2866                 .data           = &flag_print_warnings,
2867                 .maxlen         = sizeof(int),
2868                 .mode           = 0644,
2869                 .proc_handler   = proc_dointvec,
2870         },
2871 #endif
2872         { },
2873 };
2874
2875 static struct ctl_table fs_table[] = {
2876         {
2877                 .procname       = "quota",
2878                 .mode           = 0555,
2879                 .child          = fs_dqstats_table,
2880         },
2881         { },
2882 };
2883
2884 static struct ctl_table sys_table[] = {
2885         {
2886                 .procname       = "fs",
2887                 .mode           = 0555,
2888                 .child          = fs_table,
2889         },
2890         { },
2891 };
2892
2893 static int __init dquot_init(void)
2894 {
2895         int i, ret;
2896         unsigned long nr_hash, order;
2897
2898         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2899
2900         register_sysctl_table(sys_table);
2901
2902         dquot_cachep = kmem_cache_create("dquot",
2903                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2904                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2905                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2906                         NULL);
2907
2908         order = 0;
2909         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2910         if (!dquot_hash)
2911                 panic("Cannot create dquot hash table");
2912
2913         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2914                 ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
2915                 if (ret)
2916                         panic("Cannot create dquot stat counters");
2917         }
2918
2919         /* Find power-of-two hlist_heads which can fit into allocation */
2920         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2921         dq_hash_bits = 0;
2922         do {
2923                 dq_hash_bits++;
2924         } while (nr_hash >> dq_hash_bits);
2925         dq_hash_bits--;
2926
2927         nr_hash = 1UL << dq_hash_bits;
2928         dq_hash_mask = nr_hash - 1;
2929         for (i = 0; i < nr_hash; i++)
2930                 INIT_HLIST_HEAD(dquot_hash + i);
2931
2932         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
2933                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
2934
2935         register_shrinker(&dqcache_shrinker);
2936
2937         return 0;
2938 }
2939 fs_initcall(dquot_init);