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TOMOYO Linux Cross Reference
Linux/fs/quota/dquot.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Implementation of the diskquota system for the LINUX operating system. QUOTA
  4  * is implemented using the BSD system call interface as the means of
  5  * communication with the user level. This file contains the generic routines
  6  * called by the different filesystems on allocation of an inode or block.
  7  * These routines take care of the administration needed to have a consistent
  8  * diskquota tracking system. The ideas of both user and group quotas are based
  9  * on the Melbourne quota system as used on BSD derived systems. The internal
 10  * implementation is based on one of the several variants of the LINUX
 11  * inode-subsystem with added complexity of the diskquota system.
 12  *
 13  * Author:      Marco van Wieringen <mvw@planets.elm.net>
 14  *
 15  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
 16  *
 17  *              Revised list management to avoid races
 18  *              -- Bill Hawes, <whawes@star.net>, 9/98
 19  *
 20  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
 21  *              As the consequence the locking was moved from dquot_decr_...(),
 22  *              dquot_incr_...() to calling functions.
 23  *              invalidate_dquots() now writes modified dquots.
 24  *              Serialized quota_off() and quota_on() for mount point.
 25  *              Fixed a few bugs in grow_dquots().
 26  *              Fixed deadlock in write_dquot() - we no longer account quotas on
 27  *              quota files
 28  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
 29  *              add_dquot_ref() restarts after blocking
 30  *              Added check for bogus uid and fixed check for group in quotactl.
 31  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
 32  *
 33  *              Used struct list_head instead of own list struct
 34  *              Invalidation of referenced dquots is no longer possible
 35  *              Improved free_dquots list management
 36  *              Quota and i_blocks are now updated in one place to avoid races
 37  *              Warnings are now delayed so we won't block in critical section
 38  *              Write updated not to require dquot lock
 39  *              Jan Kara, <jack@suse.cz>, 9/2000
 40  *
 41  *              Added dynamic quota structure allocation
 42  *              Jan Kara <jack@suse.cz> 12/2000
 43  *
 44  *              Rewritten quota interface. Implemented new quota format and
 45  *              formats registering.
 46  *              Jan Kara, <jack@suse.cz>, 2001,2002
 47  *
 48  *              New SMP locking.
 49  *              Jan Kara, <jack@suse.cz>, 10/2002
 50  *
 51  *              Added journalled quota support, fix lock inversion problems
 52  *              Jan Kara, <jack@suse.cz>, 2003,2004
 53  *
 54  * (C) Copyright 1994 - 1997 Marco van Wieringen
 55  */
 56 
 57 #include <linux/errno.h>
 58 #include <linux/kernel.h>
 59 #include <linux/fs.h>
 60 #include <linux/mount.h>
 61 #include <linux/mm.h>
 62 #include <linux/time.h>
 63 #include <linux/types.h>
 64 #include <linux/string.h>
 65 #include <linux/fcntl.h>
 66 #include <linux/stat.h>
 67 #include <linux/tty.h>
 68 #include <linux/file.h>
 69 #include <linux/slab.h>
 70 #include <linux/sysctl.h>
 71 #include <linux/init.h>
 72 #include <linux/module.h>
 73 #include <linux/proc_fs.h>
 74 #include <linux/security.h>
 75 #include <linux/sched.h>
 76 #include <linux/cred.h>
 77 #include <linux/kmod.h>
 78 #include <linux/namei.h>
 79 #include <linux/capability.h>
 80 #include <linux/quotaops.h>
 81 #include <linux/blkdev.h>
 82 #include "../internal.h" /* ugh */
 83 
 84 #include <linux/uaccess.h>
 85 
 86 /*
 87  * There are five quota SMP locks:
 88  * * dq_list_lock protects all lists with quotas and quota formats.
 89  * * dquot->dq_dqb_lock protects data from dq_dqb
 90  * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
 91  *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
 92  *   dquot_transfer() can stabilize amount it transfers
 93  * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
 94  *   pointers in the inode
 95  * * dq_state_lock protects modifications of quota state (on quotaon and
 96  *   quotaoff) and readers who care about latest values take it as well.
 97  *
 98  * The spinlock ordering is hence:
 99  *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
100  *   dq_list_lock > dq_state_lock
101  *
102  * Note that some things (eg. sb pointer, type, id) doesn't change during
103  * the life of the dquot structure and so needn't to be protected by a lock
104  *
105  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
106  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
107  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
108  * inode and before dropping dquot references to avoid use of dquots after
109  * they are freed. dq_data_lock is used to serialize the pointer setting and
110  * clearing operations.
111  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
112  * inode is a quota file). Functions adding pointers from inode to dquots have
113  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
114  * have to do all pointer modifications before dropping dq_data_lock. This makes
115  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
116  * then drops all pointers to dquots from an inode.
117  *
118  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
119  * memory (or space for it is being allocated) on the first dqget(), when it is
120  * being written out, and when it is being released on the last dqput(). The
121  * allocation and release operations are serialized by the dq_lock and by
122  * checking the use count in dquot_release().
123  *
124  * Lock ordering (including related VFS locks) is the following:
125  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
126  */
127 
128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
129 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
130 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
131 EXPORT_SYMBOL(dq_data_lock);
132 DEFINE_STATIC_SRCU(dquot_srcu);
133 
134 static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
135 
136 void __quota_error(struct super_block *sb, const char *func,
137                    const char *fmt, ...)
138 {
139         if (printk_ratelimit()) {
140                 va_list args;
141                 struct va_format vaf;
142 
143                 va_start(args, fmt);
144 
145                 vaf.fmt = fmt;
146                 vaf.va = &args;
147 
148                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
149                        sb->s_id, func, &vaf);
150 
151                 va_end(args);
152         }
153 }
154 EXPORT_SYMBOL(__quota_error);
155 
156 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
157 static char *quotatypes[] = INITQFNAMES;
158 #endif
159 static struct quota_format_type *quota_formats; /* List of registered formats */
160 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
161 
162 /* SLAB cache for dquot structures */
163 static struct kmem_cache *dquot_cachep;
164 
165 int register_quota_format(struct quota_format_type *fmt)
166 {
167         spin_lock(&dq_list_lock);
168         fmt->qf_next = quota_formats;
169         quota_formats = fmt;
170         spin_unlock(&dq_list_lock);
171         return 0;
172 }
173 EXPORT_SYMBOL(register_quota_format);
174 
175 void unregister_quota_format(struct quota_format_type *fmt)
176 {
177         struct quota_format_type **actqf;
178 
179         spin_lock(&dq_list_lock);
180         for (actqf = &quota_formats; *actqf && *actqf != fmt;
181              actqf = &(*actqf)->qf_next)
182                 ;
183         if (*actqf)
184                 *actqf = (*actqf)->qf_next;
185         spin_unlock(&dq_list_lock);
186 }
187 EXPORT_SYMBOL(unregister_quota_format);
188 
189 static struct quota_format_type *find_quota_format(int id)
190 {
191         struct quota_format_type *actqf;
192 
193         spin_lock(&dq_list_lock);
194         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
195              actqf = actqf->qf_next)
196                 ;
197         if (!actqf || !try_module_get(actqf->qf_owner)) {
198                 int qm;
199 
200                 spin_unlock(&dq_list_lock);
201 
202                 for (qm = 0; module_names[qm].qm_fmt_id &&
203                              module_names[qm].qm_fmt_id != id; qm++)
204                         ;
205                 if (!module_names[qm].qm_fmt_id ||
206                     request_module(module_names[qm].qm_mod_name))
207                         return NULL;
208 
209                 spin_lock(&dq_list_lock);
210                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
211                      actqf = actqf->qf_next)
212                         ;
213                 if (actqf && !try_module_get(actqf->qf_owner))
214                         actqf = NULL;
215         }
216         spin_unlock(&dq_list_lock);
217         return actqf;
218 }
219 
220 static void put_quota_format(struct quota_format_type *fmt)
221 {
222         module_put(fmt->qf_owner);
223 }
224 
225 /*
226  * Dquot List Management:
227  * The quota code uses four lists for dquot management: the inuse_list,
228  * free_dquots, dqi_dirty_list, and dquot_hash[] array. A single dquot
229  * structure may be on some of those lists, depending on its current state.
230  *
231  * All dquots are placed to the end of inuse_list when first created, and this
232  * list is used for invalidate operation, which must look at every dquot.
233  *
234  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
235  * and this list is searched whenever we need an available dquot.  Dquots are
236  * removed from the list as soon as they are used again, and
237  * dqstats.free_dquots gives the number of dquots on the list. When
238  * dquot is invalidated it's completely released from memory.
239  *
240  * Dirty dquots are added to the dqi_dirty_list of quota_info when mark
241  * dirtied, and this list is searched when writing dirty dquots back to
242  * quota file. Note that some filesystems do dirty dquot tracking on their
243  * own (e.g. in a journal) and thus don't use dqi_dirty_list.
244  *
245  * Dquots with a specific identity (device, type and id) are placed on
246  * one of the dquot_hash[] hash chains. The provides an efficient search
247  * mechanism to locate a specific dquot.
248  */
249 
250 static LIST_HEAD(inuse_list);
251 static LIST_HEAD(free_dquots);
252 static unsigned int dq_hash_bits, dq_hash_mask;
253 static struct hlist_head *dquot_hash;
254 
255 struct dqstats dqstats;
256 EXPORT_SYMBOL(dqstats);
257 
258 static qsize_t inode_get_rsv_space(struct inode *inode);
259 static qsize_t __inode_get_rsv_space(struct inode *inode);
260 static int __dquot_initialize(struct inode *inode, int type);
261 
262 static inline unsigned int
263 hashfn(const struct super_block *sb, struct kqid qid)
264 {
265         unsigned int id = from_kqid(&init_user_ns, qid);
266         int type = qid.type;
267         unsigned long tmp;
268 
269         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
270         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
271 }
272 
273 /*
274  * Following list functions expect dq_list_lock to be held
275  */
276 static inline void insert_dquot_hash(struct dquot *dquot)
277 {
278         struct hlist_head *head;
279         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
280         hlist_add_head(&dquot->dq_hash, head);
281 }
282 
283 static inline void remove_dquot_hash(struct dquot *dquot)
284 {
285         hlist_del_init(&dquot->dq_hash);
286 }
287 
288 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
289                                 struct kqid qid)
290 {
291         struct hlist_node *node;
292         struct dquot *dquot;
293 
294         hlist_for_each (node, dquot_hash+hashent) {
295                 dquot = hlist_entry(node, struct dquot, dq_hash);
296                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
297                         return dquot;
298         }
299         return NULL;
300 }
301 
302 /* Add a dquot to the tail of the free list */
303 static inline void put_dquot_last(struct dquot *dquot)
304 {
305         list_add_tail(&dquot->dq_free, &free_dquots);
306         dqstats_inc(DQST_FREE_DQUOTS);
307 }
308 
309 static inline void remove_free_dquot(struct dquot *dquot)
310 {
311         if (list_empty(&dquot->dq_free))
312                 return;
313         list_del_init(&dquot->dq_free);
314         dqstats_dec(DQST_FREE_DQUOTS);
315 }
316 
317 static inline void put_inuse(struct dquot *dquot)
318 {
319         /* We add to the back of inuse list so we don't have to restart
320          * when traversing this list and we block */
321         list_add_tail(&dquot->dq_inuse, &inuse_list);
322         dqstats_inc(DQST_ALLOC_DQUOTS);
323 }
324 
325 static inline void remove_inuse(struct dquot *dquot)
326 {
327         dqstats_dec(DQST_ALLOC_DQUOTS);
328         list_del(&dquot->dq_inuse);
329 }
330 /*
331  * End of list functions needing dq_list_lock
332  */
333 
334 static void wait_on_dquot(struct dquot *dquot)
335 {
336         mutex_lock(&dquot->dq_lock);
337         mutex_unlock(&dquot->dq_lock);
338 }
339 
340 static inline int dquot_dirty(struct dquot *dquot)
341 {
342         return test_bit(DQ_MOD_B, &dquot->dq_flags);
343 }
344 
345 static inline int mark_dquot_dirty(struct dquot *dquot)
346 {
347         return dquot->dq_sb->dq_op->mark_dirty(dquot);
348 }
349 
350 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
351 int dquot_mark_dquot_dirty(struct dquot *dquot)
352 {
353         int ret = 1;
354 
355         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
356                 return 0;
357 
358         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
359                 return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
360 
361         /* If quota is dirty already, we don't have to acquire dq_list_lock */
362         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
363                 return 1;
364 
365         spin_lock(&dq_list_lock);
366         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
367                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
368                                 info[dquot->dq_id.type].dqi_dirty_list);
369                 ret = 0;
370         }
371         spin_unlock(&dq_list_lock);
372         return ret;
373 }
374 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
375 
376 /* Dirtify all the dquots - this can block when journalling */
377 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
378 {
379         int ret, err, cnt;
380 
381         ret = err = 0;
382         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
383                 if (dquot[cnt])
384                         /* Even in case of error we have to continue */
385                         ret = mark_dquot_dirty(dquot[cnt]);
386                 if (!err)
387                         err = ret;
388         }
389         return err;
390 }
391 
392 static inline void dqput_all(struct dquot **dquot)
393 {
394         unsigned int cnt;
395 
396         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
397                 dqput(dquot[cnt]);
398 }
399 
400 static inline int clear_dquot_dirty(struct dquot *dquot)
401 {
402         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
403                 return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
404 
405         spin_lock(&dq_list_lock);
406         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
407                 spin_unlock(&dq_list_lock);
408                 return 0;
409         }
410         list_del_init(&dquot->dq_dirty);
411         spin_unlock(&dq_list_lock);
412         return 1;
413 }
414 
415 void mark_info_dirty(struct super_block *sb, int type)
416 {
417         spin_lock(&dq_data_lock);
418         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
419         spin_unlock(&dq_data_lock);
420 }
421 EXPORT_SYMBOL(mark_info_dirty);
422 
423 /*
424  *      Read dquot from disk and alloc space for it
425  */
426 
427 int dquot_acquire(struct dquot *dquot)
428 {
429         int ret = 0, ret2 = 0;
430         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
431 
432         mutex_lock(&dquot->dq_lock);
433         if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
434                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
435                 if (ret < 0)
436                         goto out_iolock;
437         }
438         /* Make sure flags update is visible after dquot has been filled */
439         smp_mb__before_atomic();
440         set_bit(DQ_READ_B, &dquot->dq_flags);
441         /* Instantiate dquot if needed */
442         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
443                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
444                 /* Write the info if needed */
445                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
446                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
447                                         dquot->dq_sb, dquot->dq_id.type);
448                 }
449                 if (ret < 0)
450                         goto out_iolock;
451                 if (ret2 < 0) {
452                         ret = ret2;
453                         goto out_iolock;
454                 }
455         }
456         /*
457          * Make sure flags update is visible after on-disk struct has been
458          * allocated. Paired with smp_rmb() in dqget().
459          */
460         smp_mb__before_atomic();
461         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
462 out_iolock:
463         mutex_unlock(&dquot->dq_lock);
464         return ret;
465 }
466 EXPORT_SYMBOL(dquot_acquire);
467 
468 /*
469  *      Write dquot to disk
470  */
471 int dquot_commit(struct dquot *dquot)
472 {
473         int ret = 0;
474         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
475 
476         mutex_lock(&dquot->dq_lock);
477         if (!clear_dquot_dirty(dquot))
478                 goto out_lock;
479         /* Inactive dquot can be only if there was error during read/init
480          * => we have better not writing it */
481         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
482                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
483         else
484                 ret = -EIO;
485 out_lock:
486         mutex_unlock(&dquot->dq_lock);
487         return ret;
488 }
489 EXPORT_SYMBOL(dquot_commit);
490 
491 /*
492  *      Release dquot
493  */
494 int dquot_release(struct dquot *dquot)
495 {
496         int ret = 0, ret2 = 0;
497         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
498 
499         mutex_lock(&dquot->dq_lock);
500         /* Check whether we are not racing with some other dqget() */
501         if (dquot_is_busy(dquot))
502                 goto out_dqlock;
503         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
504                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
505                 /* Write the info */
506                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
507                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
508                                                 dquot->dq_sb, dquot->dq_id.type);
509                 }
510                 if (ret >= 0)
511                         ret = ret2;
512         }
513         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
514 out_dqlock:
515         mutex_unlock(&dquot->dq_lock);
516         return ret;
517 }
518 EXPORT_SYMBOL(dquot_release);
519 
520 void dquot_destroy(struct dquot *dquot)
521 {
522         kmem_cache_free(dquot_cachep, dquot);
523 }
524 EXPORT_SYMBOL(dquot_destroy);
525 
526 static inline void do_destroy_dquot(struct dquot *dquot)
527 {
528         dquot->dq_sb->dq_op->destroy_dquot(dquot);
529 }
530 
531 /* Invalidate all dquots on the list. Note that this function is called after
532  * quota is disabled and pointers from inodes removed so there cannot be new
533  * quota users. There can still be some users of quotas due to inodes being
534  * just deleted or pruned by prune_icache() (those are not attached to any
535  * list) or parallel quotactl call. We have to wait for such users.
536  */
537 static void invalidate_dquots(struct super_block *sb, int type)
538 {
539         struct dquot *dquot, *tmp;
540 
541 restart:
542         spin_lock(&dq_list_lock);
543         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
544                 if (dquot->dq_sb != sb)
545                         continue;
546                 if (dquot->dq_id.type != type)
547                         continue;
548                 /* Wait for dquot users */
549                 if (atomic_read(&dquot->dq_count)) {
550                         dqgrab(dquot);
551                         spin_unlock(&dq_list_lock);
552                         /*
553                          * Once dqput() wakes us up, we know it's time to free
554                          * the dquot.
555                          * IMPORTANT: we rely on the fact that there is always
556                          * at most one process waiting for dquot to free.
557                          * Otherwise dq_count would be > 1 and we would never
558                          * wake up.
559                          */
560                         wait_event(dquot_ref_wq,
561                                    atomic_read(&dquot->dq_count) == 1);
562                         dqput(dquot);
563                         /* At this moment dquot() need not exist (it could be
564                          * reclaimed by prune_dqcache(). Hence we must
565                          * restart. */
566                         goto restart;
567                 }
568                 /*
569                  * Quota now has no users and it has been written on last
570                  * dqput()
571                  */
572                 remove_dquot_hash(dquot);
573                 remove_free_dquot(dquot);
574                 remove_inuse(dquot);
575                 do_destroy_dquot(dquot);
576         }
577         spin_unlock(&dq_list_lock);
578 }
579 
580 /* Call callback for every active dquot on given filesystem */
581 int dquot_scan_active(struct super_block *sb,
582                       int (*fn)(struct dquot *dquot, unsigned long priv),
583                       unsigned long priv)
584 {
585         struct dquot *dquot, *old_dquot = NULL;
586         int ret = 0;
587 
588         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
589 
590         spin_lock(&dq_list_lock);
591         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
592                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
593                         continue;
594                 if (dquot->dq_sb != sb)
595                         continue;
596                 /* Now we have active dquot so we can just increase use count */
597                 atomic_inc(&dquot->dq_count);
598                 spin_unlock(&dq_list_lock);
599                 dqput(old_dquot);
600                 old_dquot = dquot;
601                 /*
602                  * ->release_dquot() can be racing with us. Our reference
603                  * protects us from new calls to it so just wait for any
604                  * outstanding call and recheck the DQ_ACTIVE_B after that.
605                  */
606                 wait_on_dquot(dquot);
607                 if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
608                         ret = fn(dquot, priv);
609                         if (ret < 0)
610                                 goto out;
611                 }
612                 spin_lock(&dq_list_lock);
613                 /* We are safe to continue now because our dquot could not
614                  * be moved out of the inuse list while we hold the reference */
615         }
616         spin_unlock(&dq_list_lock);
617 out:
618         dqput(old_dquot);
619         return ret;
620 }
621 EXPORT_SYMBOL(dquot_scan_active);
622 
623 /* Write all dquot structures to quota files */
624 int dquot_writeback_dquots(struct super_block *sb, int type)
625 {
626         struct list_head dirty;
627         struct dquot *dquot;
628         struct quota_info *dqopt = sb_dqopt(sb);
629         int cnt;
630         int err, ret = 0;
631 
632         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
633 
634         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
635                 if (type != -1 && cnt != type)
636                         continue;
637                 if (!sb_has_quota_active(sb, cnt))
638                         continue;
639                 spin_lock(&dq_list_lock);
640                 /* Move list away to avoid livelock. */
641                 list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty);
642                 while (!list_empty(&dirty)) {
643                         dquot = list_first_entry(&dirty, struct dquot,
644                                                  dq_dirty);
645 
646                         WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
647 
648                         /* Now we have active dquot from which someone is
649                          * holding reference so we can safely just increase
650                          * use count */
651                         dqgrab(dquot);
652                         spin_unlock(&dq_list_lock);
653                         err = sb->dq_op->write_dquot(dquot);
654                         if (err) {
655                                 /*
656                                  * Clear dirty bit anyway to avoid infinite
657                                  * loop here.
658                                  */
659                                 clear_dquot_dirty(dquot);
660                                 if (!ret)
661                                         ret = err;
662                         }
663                         dqput(dquot);
664                         spin_lock(&dq_list_lock);
665                 }
666                 spin_unlock(&dq_list_lock);
667         }
668 
669         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
670                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
671                     && info_dirty(&dqopt->info[cnt]))
672                         sb->dq_op->write_info(sb, cnt);
673         dqstats_inc(DQST_SYNCS);
674 
675         return ret;
676 }
677 EXPORT_SYMBOL(dquot_writeback_dquots);
678 
679 /* Write all dquot structures to disk and make them visible from userspace */
680 int dquot_quota_sync(struct super_block *sb, int type)
681 {
682         struct quota_info *dqopt = sb_dqopt(sb);
683         int cnt;
684         int ret;
685 
686         ret = dquot_writeback_dquots(sb, type);
687         if (ret)
688                 return ret;
689         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
690                 return 0;
691 
692         /* This is not very clever (and fast) but currently I don't know about
693          * any other simple way of getting quota data to disk and we must get
694          * them there for userspace to be visible... */
695         if (sb->s_op->sync_fs)
696                 sb->s_op->sync_fs(sb, 1);
697         sync_blockdev(sb->s_bdev);
698 
699         /*
700          * Now when everything is written we can discard the pagecache so
701          * that userspace sees the changes.
702          */
703         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
704                 if (type != -1 && cnt != type)
705                         continue;
706                 if (!sb_has_quota_active(sb, cnt))
707                         continue;
708                 inode_lock(dqopt->files[cnt]);
709                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
710                 inode_unlock(dqopt->files[cnt]);
711         }
712 
713         return 0;
714 }
715 EXPORT_SYMBOL(dquot_quota_sync);
716 
717 static unsigned long
718 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
719 {
720         struct dquot *dquot;
721         unsigned long freed = 0;
722 
723         spin_lock(&dq_list_lock);
724         while (!list_empty(&free_dquots) && sc->nr_to_scan) {
725                 dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
726                 remove_dquot_hash(dquot);
727                 remove_free_dquot(dquot);
728                 remove_inuse(dquot);
729                 do_destroy_dquot(dquot);
730                 sc->nr_to_scan--;
731                 freed++;
732         }
733         spin_unlock(&dq_list_lock);
734         return freed;
735 }
736 
737 static unsigned long
738 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
739 {
740         return vfs_pressure_ratio(
741         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
742 }
743 
744 static struct shrinker dqcache_shrinker = {
745         .count_objects = dqcache_shrink_count,
746         .scan_objects = dqcache_shrink_scan,
747         .seeks = DEFAULT_SEEKS,
748 };
749 
750 /*
751  * Put reference to dquot
752  */
753 void dqput(struct dquot *dquot)
754 {
755         int ret;
756 
757         if (!dquot)
758                 return;
759 #ifdef CONFIG_QUOTA_DEBUG
760         if (!atomic_read(&dquot->dq_count)) {
761                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
762                             quotatypes[dquot->dq_id.type],
763                             from_kqid(&init_user_ns, dquot->dq_id));
764                 BUG();
765         }
766 #endif
767         dqstats_inc(DQST_DROPS);
768 we_slept:
769         spin_lock(&dq_list_lock);
770         if (atomic_read(&dquot->dq_count) > 1) {
771                 /* We have more than one user... nothing to do */
772                 atomic_dec(&dquot->dq_count);
773                 /* Releasing dquot during quotaoff phase? */
774                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
775                     atomic_read(&dquot->dq_count) == 1)
776                         wake_up(&dquot_ref_wq);
777                 spin_unlock(&dq_list_lock);
778                 return;
779         }
780         /* Need to release dquot? */
781         if (dquot_dirty(dquot)) {
782                 spin_unlock(&dq_list_lock);
783                 /* Commit dquot before releasing */
784                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
785                 if (ret < 0) {
786                         quota_error(dquot->dq_sb, "Can't write quota structure"
787                                     " (error %d). Quota may get out of sync!",
788                                     ret);
789                         /*
790                          * We clear dirty bit anyway, so that we avoid
791                          * infinite loop here
792                          */
793                         clear_dquot_dirty(dquot);
794                 }
795                 goto we_slept;
796         }
797         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
798                 spin_unlock(&dq_list_lock);
799                 dquot->dq_sb->dq_op->release_dquot(dquot);
800                 goto we_slept;
801         }
802         atomic_dec(&dquot->dq_count);
803 #ifdef CONFIG_QUOTA_DEBUG
804         /* sanity check */
805         BUG_ON(!list_empty(&dquot->dq_free));
806 #endif
807         put_dquot_last(dquot);
808         spin_unlock(&dq_list_lock);
809 }
810 EXPORT_SYMBOL(dqput);
811 
812 struct dquot *dquot_alloc(struct super_block *sb, int type)
813 {
814         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
815 }
816 EXPORT_SYMBOL(dquot_alloc);
817 
818 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
819 {
820         struct dquot *dquot;
821 
822         dquot = sb->dq_op->alloc_dquot(sb, type);
823         if(!dquot)
824                 return NULL;
825 
826         mutex_init(&dquot->dq_lock);
827         INIT_LIST_HEAD(&dquot->dq_free);
828         INIT_LIST_HEAD(&dquot->dq_inuse);
829         INIT_HLIST_NODE(&dquot->dq_hash);
830         INIT_LIST_HEAD(&dquot->dq_dirty);
831         dquot->dq_sb = sb;
832         dquot->dq_id = make_kqid_invalid(type);
833         atomic_set(&dquot->dq_count, 1);
834         spin_lock_init(&dquot->dq_dqb_lock);
835 
836         return dquot;
837 }
838 
839 /*
840  * Get reference to dquot
841  *
842  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
843  * destroying our dquot by:
844  *   a) checking for quota flags under dq_list_lock and
845  *   b) getting a reference to dquot before we release dq_list_lock
846  */
847 struct dquot *dqget(struct super_block *sb, struct kqid qid)
848 {
849         unsigned int hashent = hashfn(sb, qid);
850         struct dquot *dquot, *empty = NULL;
851 
852         if (!qid_has_mapping(sb->s_user_ns, qid))
853                 return ERR_PTR(-EINVAL);
854 
855         if (!sb_has_quota_active(sb, qid.type))
856                 return ERR_PTR(-ESRCH);
857 we_slept:
858         spin_lock(&dq_list_lock);
859         spin_lock(&dq_state_lock);
860         if (!sb_has_quota_active(sb, qid.type)) {
861                 spin_unlock(&dq_state_lock);
862                 spin_unlock(&dq_list_lock);
863                 dquot = ERR_PTR(-ESRCH);
864                 goto out;
865         }
866         spin_unlock(&dq_state_lock);
867 
868         dquot = find_dquot(hashent, sb, qid);
869         if (!dquot) {
870                 if (!empty) {
871                         spin_unlock(&dq_list_lock);
872                         empty = get_empty_dquot(sb, qid.type);
873                         if (!empty)
874                                 schedule();     /* Try to wait for a moment... */
875                         goto we_slept;
876                 }
877                 dquot = empty;
878                 empty = NULL;
879                 dquot->dq_id = qid;
880                 /* all dquots go on the inuse_list */
881                 put_inuse(dquot);
882                 /* hash it first so it can be found */
883                 insert_dquot_hash(dquot);
884                 spin_unlock(&dq_list_lock);
885                 dqstats_inc(DQST_LOOKUPS);
886         } else {
887                 if (!atomic_read(&dquot->dq_count))
888                         remove_free_dquot(dquot);
889                 atomic_inc(&dquot->dq_count);
890                 spin_unlock(&dq_list_lock);
891                 dqstats_inc(DQST_CACHE_HITS);
892                 dqstats_inc(DQST_LOOKUPS);
893         }
894         /* Wait for dq_lock - after this we know that either dquot_release() is
895          * already finished or it will be canceled due to dq_count > 1 test */
896         wait_on_dquot(dquot);
897         /* Read the dquot / allocate space in quota file */
898         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
899                 int err;
900 
901                 err = sb->dq_op->acquire_dquot(dquot);
902                 if (err < 0) {
903                         dqput(dquot);
904                         dquot = ERR_PTR(err);
905                         goto out;
906                 }
907         }
908         /*
909          * Make sure following reads see filled structure - paired with
910          * smp_mb__before_atomic() in dquot_acquire().
911          */
912         smp_rmb();
913 #ifdef CONFIG_QUOTA_DEBUG
914         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
915 #endif
916 out:
917         if (empty)
918                 do_destroy_dquot(empty);
919 
920         return dquot;
921 }
922 EXPORT_SYMBOL(dqget);
923 
924 static inline struct dquot **i_dquot(struct inode *inode)
925 {
926         return inode->i_sb->s_op->get_dquots(inode);
927 }
928 
929 static int dqinit_needed(struct inode *inode, int type)
930 {
931         struct dquot * const *dquots;
932         int cnt;
933 
934         if (IS_NOQUOTA(inode))
935                 return 0;
936 
937         dquots = i_dquot(inode);
938         if (type != -1)
939                 return !dquots[type];
940         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
941                 if (!dquots[cnt])
942                         return 1;
943         return 0;
944 }
945 
946 /* This routine is guarded by s_umount semaphore */
947 static int add_dquot_ref(struct super_block *sb, int type)
948 {
949         struct inode *inode, *old_inode = NULL;
950 #ifdef CONFIG_QUOTA_DEBUG
951         int reserved = 0;
952 #endif
953         int err = 0;
954 
955         spin_lock(&sb->s_inode_list_lock);
956         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
957                 spin_lock(&inode->i_lock);
958                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
959                     !atomic_read(&inode->i_writecount) ||
960                     !dqinit_needed(inode, type)) {
961                         spin_unlock(&inode->i_lock);
962                         continue;
963                 }
964                 __iget(inode);
965                 spin_unlock(&inode->i_lock);
966                 spin_unlock(&sb->s_inode_list_lock);
967 
968 #ifdef CONFIG_QUOTA_DEBUG
969                 if (unlikely(inode_get_rsv_space(inode) > 0))
970                         reserved = 1;
971 #endif
972                 iput(old_inode);
973                 err = __dquot_initialize(inode, type);
974                 if (err) {
975                         iput(inode);
976                         goto out;
977                 }
978 
979                 /*
980                  * We hold a reference to 'inode' so it couldn't have been
981                  * removed from s_inodes list while we dropped the
982                  * s_inode_list_lock. We cannot iput the inode now as we can be
983                  * holding the last reference and we cannot iput it under
984                  * s_inode_list_lock. So we keep the reference and iput it
985                  * later.
986                  */
987                 old_inode = inode;
988                 cond_resched();
989                 spin_lock(&sb->s_inode_list_lock);
990         }
991         spin_unlock(&sb->s_inode_list_lock);
992         iput(old_inode);
993 out:
994 #ifdef CONFIG_QUOTA_DEBUG
995         if (reserved) {
996                 quota_error(sb, "Writes happened before quota was turned on "
997                         "thus quota information is probably inconsistent. "
998                         "Please run quotacheck(8)");
999         }
1000 #endif
1001         return err;
1002 }
1003 
1004 /*
1005  * Remove references to dquots from inode and add dquot to list for freeing
1006  * if we have the last reference to dquot
1007  */
1008 static void remove_inode_dquot_ref(struct inode *inode, int type,
1009                                    struct list_head *tofree_head)
1010 {
1011         struct dquot **dquots = i_dquot(inode);
1012         struct dquot *dquot = dquots[type];
1013 
1014         if (!dquot)
1015                 return;
1016 
1017         dquots[type] = NULL;
1018         if (list_empty(&dquot->dq_free)) {
1019                 /*
1020                  * The inode still has reference to dquot so it can't be in the
1021                  * free list
1022                  */
1023                 spin_lock(&dq_list_lock);
1024                 list_add(&dquot->dq_free, tofree_head);
1025                 spin_unlock(&dq_list_lock);
1026         } else {
1027                 /*
1028                  * Dquot is already in a list to put so we won't drop the last
1029                  * reference here.
1030                  */
1031                 dqput(dquot);
1032         }
1033 }
1034 
1035 /*
1036  * Free list of dquots
1037  * Dquots are removed from inodes and no new references can be got so we are
1038  * the only ones holding reference
1039  */
1040 static void put_dquot_list(struct list_head *tofree_head)
1041 {
1042         struct list_head *act_head;
1043         struct dquot *dquot;
1044 
1045         act_head = tofree_head->next;
1046         while (act_head != tofree_head) {
1047                 dquot = list_entry(act_head, struct dquot, dq_free);
1048                 act_head = act_head->next;
1049                 /* Remove dquot from the list so we won't have problems... */
1050                 list_del_init(&dquot->dq_free);
1051                 dqput(dquot);
1052         }
1053 }
1054 
1055 static void remove_dquot_ref(struct super_block *sb, int type,
1056                 struct list_head *tofree_head)
1057 {
1058         struct inode *inode;
1059 #ifdef CONFIG_QUOTA_DEBUG
1060         int reserved = 0;
1061 #endif
1062 
1063         spin_lock(&sb->s_inode_list_lock);
1064         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1065                 /*
1066                  *  We have to scan also I_NEW inodes because they can already
1067                  *  have quota pointer initialized. Luckily, we need to touch
1068                  *  only quota pointers and these have separate locking
1069                  *  (dq_data_lock).
1070                  */
1071                 spin_lock(&dq_data_lock);
1072                 if (!IS_NOQUOTA(inode)) {
1073 #ifdef CONFIG_QUOTA_DEBUG
1074                         if (unlikely(inode_get_rsv_space(inode) > 0))
1075                                 reserved = 1;
1076 #endif
1077                         remove_inode_dquot_ref(inode, type, tofree_head);
1078                 }
1079                 spin_unlock(&dq_data_lock);
1080         }
1081         spin_unlock(&sb->s_inode_list_lock);
1082 #ifdef CONFIG_QUOTA_DEBUG
1083         if (reserved) {
1084                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1085                         " was disabled thus quota information is probably "
1086                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1087         }
1088 #endif
1089 }
1090 
1091 /* Gather all references from inodes and drop them */
1092 static void drop_dquot_ref(struct super_block *sb, int type)
1093 {
1094         LIST_HEAD(tofree_head);
1095 
1096         if (sb->dq_op) {
1097                 remove_dquot_ref(sb, type, &tofree_head);
1098                 synchronize_srcu(&dquot_srcu);
1099                 put_dquot_list(&tofree_head);
1100         }
1101 }
1102 
1103 static inline
1104 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1105 {
1106         if (dquot->dq_dqb.dqb_rsvspace >= number)
1107                 dquot->dq_dqb.dqb_rsvspace -= number;
1108         else {
1109                 WARN_ON_ONCE(1);
1110                 dquot->dq_dqb.dqb_rsvspace = 0;
1111         }
1112         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1113             dquot->dq_dqb.dqb_bsoftlimit)
1114                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1115         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1116 }
1117 
1118 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1119 {
1120         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1121             dquot->dq_dqb.dqb_curinodes >= number)
1122                 dquot->dq_dqb.dqb_curinodes -= number;
1123         else
1124                 dquot->dq_dqb.dqb_curinodes = 0;
1125         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1126                 dquot->dq_dqb.dqb_itime = (time64_t) 0;
1127         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1128 }
1129 
1130 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1131 {
1132         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1133             dquot->dq_dqb.dqb_curspace >= number)
1134                 dquot->dq_dqb.dqb_curspace -= number;
1135         else
1136                 dquot->dq_dqb.dqb_curspace = 0;
1137         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1138             dquot->dq_dqb.dqb_bsoftlimit)
1139                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1140         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1141 }
1142 
1143 struct dquot_warn {
1144         struct super_block *w_sb;
1145         struct kqid w_dq_id;
1146         short w_type;
1147 };
1148 
1149 static int warning_issued(struct dquot *dquot, const int warntype)
1150 {
1151         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1152                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1153                 ((warntype == QUOTA_NL_IHARDWARN ||
1154                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1155 
1156         if (!flag)
1157                 return 0;
1158         return test_and_set_bit(flag, &dquot->dq_flags);
1159 }
1160 
1161 #ifdef CONFIG_PRINT_QUOTA_WARNING
1162 static int flag_print_warnings = 1;
1163 
1164 static int need_print_warning(struct dquot_warn *warn)
1165 {
1166         if (!flag_print_warnings)
1167                 return 0;
1168 
1169         switch (warn->w_dq_id.type) {
1170                 case USRQUOTA:
1171                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1172                 case GRPQUOTA:
1173                         return in_group_p(warn->w_dq_id.gid);
1174                 case PRJQUOTA:
1175                         return 1;
1176         }
1177         return 0;
1178 }
1179 
1180 /* Print warning to user which exceeded quota */
1181 static void print_warning(struct dquot_warn *warn)
1182 {
1183         char *msg = NULL;
1184         struct tty_struct *tty;
1185         int warntype = warn->w_type;
1186 
1187         if (warntype == QUOTA_NL_IHARDBELOW ||
1188             warntype == QUOTA_NL_ISOFTBELOW ||
1189             warntype == QUOTA_NL_BHARDBELOW ||
1190             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1191                 return;
1192 
1193         tty = get_current_tty();
1194         if (!tty)
1195                 return;
1196         tty_write_message(tty, warn->w_sb->s_id);
1197         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1198                 tty_write_message(tty, ": warning, ");
1199         else
1200                 tty_write_message(tty, ": write failed, ");
1201         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1202         switch (warntype) {
1203                 case QUOTA_NL_IHARDWARN:
1204                         msg = " file limit reached.\r\n";
1205                         break;
1206                 case QUOTA_NL_ISOFTLONGWARN:
1207                         msg = " file quota exceeded too long.\r\n";
1208                         break;
1209                 case QUOTA_NL_ISOFTWARN:
1210                         msg = " file quota exceeded.\r\n";
1211                         break;
1212                 case QUOTA_NL_BHARDWARN:
1213                         msg = " block limit reached.\r\n";
1214                         break;
1215                 case QUOTA_NL_BSOFTLONGWARN:
1216                         msg = " block quota exceeded too long.\r\n";
1217                         break;
1218                 case QUOTA_NL_BSOFTWARN:
1219                         msg = " block quota exceeded.\r\n";
1220                         break;
1221         }
1222         tty_write_message(tty, msg);
1223         tty_kref_put(tty);
1224 }
1225 #endif
1226 
1227 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1228                             int warntype)
1229 {
1230         if (warning_issued(dquot, warntype))
1231                 return;
1232         warn->w_type = warntype;
1233         warn->w_sb = dquot->dq_sb;
1234         warn->w_dq_id = dquot->dq_id;
1235 }
1236 
1237 /*
1238  * Write warnings to the console and send warning messages over netlink.
1239  *
1240  * Note that this function can call into tty and networking code.
1241  */
1242 static void flush_warnings(struct dquot_warn *warn)
1243 {
1244         int i;
1245 
1246         for (i = 0; i < MAXQUOTAS; i++) {
1247                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1248                         continue;
1249 #ifdef CONFIG_PRINT_QUOTA_WARNING
1250                 print_warning(&warn[i]);
1251 #endif
1252                 quota_send_warning(warn[i].w_dq_id,
1253                                    warn[i].w_sb->s_dev, warn[i].w_type);
1254         }
1255 }
1256 
1257 static int ignore_hardlimit(struct dquot *dquot)
1258 {
1259         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1260 
1261         return capable(CAP_SYS_RESOURCE) &&
1262                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1263                 !(info->dqi_flags & DQF_ROOT_SQUASH));
1264 }
1265 
1266 static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
1267                             struct dquot_warn *warn)
1268 {
1269         qsize_t newinodes;
1270         int ret = 0;
1271 
1272         spin_lock(&dquot->dq_dqb_lock);
1273         newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1274         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1275             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1276                 goto add;
1277 
1278         if (dquot->dq_dqb.dqb_ihardlimit &&
1279             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1280             !ignore_hardlimit(dquot)) {
1281                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1282                 ret = -EDQUOT;
1283                 goto out;
1284         }
1285 
1286         if (dquot->dq_dqb.dqb_isoftlimit &&
1287             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1288             dquot->dq_dqb.dqb_itime &&
1289             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
1290             !ignore_hardlimit(dquot)) {
1291                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1292                 ret = -EDQUOT;
1293                 goto out;
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 add:
1304         dquot->dq_dqb.dqb_curinodes = newinodes;
1305 
1306 out:
1307         spin_unlock(&dquot->dq_dqb_lock);
1308         return ret;
1309 }
1310 
1311 static int dquot_add_space(struct dquot *dquot, qsize_t space,
1312                            qsize_t rsv_space, unsigned int flags,
1313                            struct dquot_warn *warn)
1314 {
1315         qsize_t tspace;
1316         struct super_block *sb = dquot->dq_sb;
1317         int ret = 0;
1318 
1319         spin_lock(&dquot->dq_dqb_lock);
1320         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1321             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1322                 goto finish;
1323 
1324         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1325                 + space + rsv_space;
1326 
1327         if (dquot->dq_dqb.dqb_bhardlimit &&
1328             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1329             !ignore_hardlimit(dquot)) {
1330                 if (flags & DQUOT_SPACE_WARN)
1331                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1332                 ret = -EDQUOT;
1333                 goto finish;
1334         }
1335 
1336         if (dquot->dq_dqb.dqb_bsoftlimit &&
1337             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1338             dquot->dq_dqb.dqb_btime &&
1339             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
1340             !ignore_hardlimit(dquot)) {
1341                 if (flags & DQUOT_SPACE_WARN)
1342                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1343                 ret = -EDQUOT;
1344                 goto finish;
1345         }
1346 
1347         if (dquot->dq_dqb.dqb_bsoftlimit &&
1348             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1349             dquot->dq_dqb.dqb_btime == 0) {
1350                 if (flags & DQUOT_SPACE_WARN) {
1351                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1352                         dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
1353                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1354                 } else {
1355                         /*
1356                          * We don't allow preallocation to exceed softlimit so exceeding will
1357                          * be always printed
1358                          */
1359                         ret = -EDQUOT;
1360                         goto finish;
1361                 }
1362         }
1363 finish:
1364         /*
1365          * We have to be careful and go through warning generation & grace time
1366          * setting even if DQUOT_SPACE_NOFAIL is set. That's why we check it
1367          * only here...
1368          */
1369         if (flags & DQUOT_SPACE_NOFAIL)
1370                 ret = 0;
1371         if (!ret) {
1372                 dquot->dq_dqb.dqb_rsvspace += rsv_space;
1373                 dquot->dq_dqb.dqb_curspace += space;
1374         }
1375         spin_unlock(&dquot->dq_dqb_lock);
1376         return ret;
1377 }
1378 
1379 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1380 {
1381         qsize_t newinodes;
1382 
1383         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1384             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1385             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1386                 return QUOTA_NL_NOWARN;
1387 
1388         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1389         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1390                 return QUOTA_NL_ISOFTBELOW;
1391         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1392             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1393                 return QUOTA_NL_IHARDBELOW;
1394         return QUOTA_NL_NOWARN;
1395 }
1396 
1397 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1398 {
1399         qsize_t tspace;
1400 
1401         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace;
1402 
1403         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1404             tspace <= dquot->dq_dqb.dqb_bsoftlimit)
1405                 return QUOTA_NL_NOWARN;
1406 
1407         if (tspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1408                 return QUOTA_NL_BSOFTBELOW;
1409         if (tspace >= dquot->dq_dqb.dqb_bhardlimit &&
1410             tspace - space < dquot->dq_dqb.dqb_bhardlimit)
1411                 return QUOTA_NL_BHARDBELOW;
1412         return QUOTA_NL_NOWARN;
1413 }
1414 
1415 static int dquot_active(const struct inode *inode)
1416 {
1417         struct super_block *sb = inode->i_sb;
1418 
1419         if (IS_NOQUOTA(inode))
1420                 return 0;
1421         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1422 }
1423 
1424 /*
1425  * Initialize quota pointers in inode
1426  *
1427  * It is better to call this function outside of any transaction as it
1428  * might need a lot of space in journal for dquot structure allocation.
1429  */
1430 static int __dquot_initialize(struct inode *inode, int type)
1431 {
1432         int cnt, init_needed = 0;
1433         struct dquot **dquots, *got[MAXQUOTAS] = {};
1434         struct super_block *sb = inode->i_sb;
1435         qsize_t rsv;
1436         int ret = 0;
1437 
1438         if (!dquot_active(inode))
1439                 return 0;
1440 
1441         dquots = i_dquot(inode);
1442 
1443         /* First get references to structures we might need. */
1444         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1445                 struct kqid qid;
1446                 kprojid_t projid;
1447                 int rc;
1448                 struct dquot *dquot;
1449 
1450                 if (type != -1 && cnt != type)
1451                         continue;
1452                 /*
1453                  * The i_dquot should have been initialized in most cases,
1454                  * we check it without locking here to avoid unnecessary
1455                  * dqget()/dqput() calls.
1456                  */
1457                 if (dquots[cnt])
1458                         continue;
1459 
1460                 if (!sb_has_quota_active(sb, cnt))
1461                         continue;
1462 
1463                 init_needed = 1;
1464 
1465                 switch (cnt) {
1466                 case USRQUOTA:
1467                         qid = make_kqid_uid(inode->i_uid);
1468                         break;
1469                 case GRPQUOTA:
1470                         qid = make_kqid_gid(inode->i_gid);
1471                         break;
1472                 case PRJQUOTA:
1473                         rc = inode->i_sb->dq_op->get_projid(inode, &projid);
1474                         if (rc)
1475                                 continue;
1476                         qid = make_kqid_projid(projid);
1477                         break;
1478                 }
1479                 dquot = dqget(sb, qid);
1480                 if (IS_ERR(dquot)) {
1481                         /* We raced with somebody turning quotas off... */
1482                         if (PTR_ERR(dquot) != -ESRCH) {
1483                                 ret = PTR_ERR(dquot);
1484                                 goto out_put;
1485                         }
1486                         dquot = NULL;
1487                 }
1488                 got[cnt] = dquot;
1489         }
1490 
1491         /* All required i_dquot has been initialized */
1492         if (!init_needed)
1493                 return 0;
1494 
1495         spin_lock(&dq_data_lock);
1496         if (IS_NOQUOTA(inode))
1497                 goto out_lock;
1498         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1499                 if (type != -1 && cnt != type)
1500                         continue;
1501                 /* Avoid races with quotaoff() */
1502                 if (!sb_has_quota_active(sb, cnt))
1503                         continue;
1504                 /* We could race with quotaon or dqget() could have failed */
1505                 if (!got[cnt])
1506                         continue;
1507                 if (!dquots[cnt]) {
1508                         dquots[cnt] = got[cnt];
1509                         got[cnt] = NULL;
1510                         /*
1511                          * Make quota reservation system happy if someone
1512                          * did a write before quota was turned on
1513                          */
1514                         rsv = inode_get_rsv_space(inode);
1515                         if (unlikely(rsv)) {
1516                                 spin_lock(&inode->i_lock);
1517                                 /* Get reservation again under proper lock */
1518                                 rsv = __inode_get_rsv_space(inode);
1519                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1520                                 dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
1521                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1522                                 spin_unlock(&inode->i_lock);
1523                         }
1524                 }
1525         }
1526 out_lock:
1527         spin_unlock(&dq_data_lock);
1528 out_put:
1529         /* Drop unused references */
1530         dqput_all(got);
1531 
1532         return ret;
1533 }
1534 
1535 int dquot_initialize(struct inode *inode)
1536 {
1537         return __dquot_initialize(inode, -1);
1538 }
1539 EXPORT_SYMBOL(dquot_initialize);
1540 
1541 bool dquot_initialize_needed(struct inode *inode)
1542 {
1543         struct dquot **dquots;
1544         int i;
1545 
1546         if (!dquot_active(inode))
1547                 return false;
1548 
1549         dquots = i_dquot(inode);
1550         for (i = 0; i < MAXQUOTAS; i++)
1551                 if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
1552                         return true;
1553         return false;
1554 }
1555 EXPORT_SYMBOL(dquot_initialize_needed);
1556 
1557 /*
1558  * Release all quotas referenced by inode.
1559  *
1560  * This function only be called on inode free or converting
1561  * a file to quota file, no other users for the i_dquot in
1562  * both cases, so we needn't call synchronize_srcu() after
1563  * clearing i_dquot.
1564  */
1565 static void __dquot_drop(struct inode *inode)
1566 {
1567         int cnt;
1568         struct dquot **dquots = i_dquot(inode);
1569         struct dquot *put[MAXQUOTAS];
1570 
1571         spin_lock(&dq_data_lock);
1572         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1573                 put[cnt] = dquots[cnt];
1574                 dquots[cnt] = NULL;
1575         }
1576         spin_unlock(&dq_data_lock);
1577         dqput_all(put);
1578 }
1579 
1580 void dquot_drop(struct inode *inode)
1581 {
1582         struct dquot * const *dquots;
1583         int cnt;
1584 
1585         if (IS_NOQUOTA(inode))
1586                 return;
1587 
1588         /*
1589          * Test before calling to rule out calls from proc and such
1590          * where we are not allowed to block. Note that this is
1591          * actually reliable test even without the lock - the caller
1592          * must assure that nobody can come after the DQUOT_DROP and
1593          * add quota pointers back anyway.
1594          */
1595         dquots = i_dquot(inode);
1596         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1597                 if (dquots[cnt])
1598                         break;
1599         }
1600 
1601         if (cnt < MAXQUOTAS)
1602                 __dquot_drop(inode);
1603 }
1604 EXPORT_SYMBOL(dquot_drop);
1605 
1606 /*
1607  * inode_reserved_space is managed internally by quota, and protected by
1608  * i_lock similar to i_blocks+i_bytes.
1609  */
1610 static qsize_t *inode_reserved_space(struct inode * inode)
1611 {
1612         /* Filesystem must explicitly define it's own method in order to use
1613          * quota reservation interface */
1614         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1615         return inode->i_sb->dq_op->get_reserved_space(inode);
1616 }
1617 
1618 static qsize_t __inode_get_rsv_space(struct inode *inode)
1619 {
1620         if (!inode->i_sb->dq_op->get_reserved_space)
1621                 return 0;
1622         return *inode_reserved_space(inode);
1623 }
1624 
1625 static qsize_t inode_get_rsv_space(struct inode *inode)
1626 {
1627         qsize_t ret;
1628 
1629         if (!inode->i_sb->dq_op->get_reserved_space)
1630                 return 0;
1631         spin_lock(&inode->i_lock);
1632         ret = __inode_get_rsv_space(inode);
1633         spin_unlock(&inode->i_lock);
1634         return ret;
1635 }
1636 
1637 /*
1638  * This functions updates i_blocks+i_bytes fields and quota information
1639  * (together with appropriate checks).
1640  *
1641  * NOTE: We absolutely rely on the fact that caller dirties the inode
1642  * (usually helpers in quotaops.h care about this) and holds a handle for
1643  * the current transaction so that dquot write and inode write go into the
1644  * same transaction.
1645  */
1646 
1647 /*
1648  * This operation can block, but only after everything is updated
1649  */
1650 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1651 {
1652         int cnt, ret = 0, index;
1653         struct dquot_warn warn[MAXQUOTAS];
1654         int reserve = flags & DQUOT_SPACE_RESERVE;
1655         struct dquot **dquots;
1656 
1657         if (!dquot_active(inode)) {
1658                 if (reserve) {
1659                         spin_lock(&inode->i_lock);
1660                         *inode_reserved_space(inode) += number;
1661                         spin_unlock(&inode->i_lock);
1662                 } else {
1663                         inode_add_bytes(inode, number);
1664                 }
1665                 goto out;
1666         }
1667 
1668         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1669                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1670 
1671         dquots = i_dquot(inode);
1672         index = srcu_read_lock(&dquot_srcu);
1673         spin_lock(&inode->i_lock);
1674         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1675                 if (!dquots[cnt])
1676                         continue;
1677                 if (reserve) {
1678                         ret = dquot_add_space(dquots[cnt], 0, number, flags,
1679                                               &warn[cnt]);
1680                 } else {
1681                         ret = dquot_add_space(dquots[cnt], number, 0, flags,
1682                                               &warn[cnt]);
1683                 }
1684                 if (ret) {
1685                         /* Back out changes we already did */
1686                         for (cnt--; cnt >= 0; cnt--) {
1687                                 if (!dquots[cnt])
1688                                         continue;
1689                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1690                                 if (reserve)
1691                                         dquot_free_reserved_space(dquots[cnt],
1692                                                                   number);
1693                                 else
1694                                         dquot_decr_space(dquots[cnt], number);
1695                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1696                         }
1697                         spin_unlock(&inode->i_lock);
1698                         goto out_flush_warn;
1699                 }
1700         }
1701         if (reserve)
1702                 *inode_reserved_space(inode) += number;
1703         else
1704                 __inode_add_bytes(inode, number);
1705         spin_unlock(&inode->i_lock);
1706 
1707         if (reserve)
1708                 goto out_flush_warn;
1709         mark_all_dquot_dirty(dquots);
1710 out_flush_warn:
1711         srcu_read_unlock(&dquot_srcu, index);
1712         flush_warnings(warn);
1713 out:
1714         return ret;
1715 }
1716 EXPORT_SYMBOL(__dquot_alloc_space);
1717 
1718 /*
1719  * This operation can block, but only after everything is updated
1720  */
1721 int dquot_alloc_inode(struct inode *inode)
1722 {
1723         int cnt, ret = 0, index;
1724         struct dquot_warn warn[MAXQUOTAS];
1725         struct dquot * const *dquots;
1726 
1727         if (!dquot_active(inode))
1728                 return 0;
1729         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1730                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1731 
1732         dquots = i_dquot(inode);
1733         index = srcu_read_lock(&dquot_srcu);
1734         spin_lock(&inode->i_lock);
1735         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1736                 if (!dquots[cnt])
1737                         continue;
1738                 ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
1739                 if (ret) {
1740                         for (cnt--; cnt >= 0; cnt--) {
1741                                 if (!dquots[cnt])
1742                                         continue;
1743                                 /* Back out changes we already did */
1744                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1745                                 dquot_decr_inodes(dquots[cnt], 1);
1746                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1747                         }
1748                         goto warn_put_all;
1749                 }
1750         }
1751 
1752 warn_put_all:
1753         spin_unlock(&inode->i_lock);
1754         if (ret == 0)
1755                 mark_all_dquot_dirty(dquots);
1756         srcu_read_unlock(&dquot_srcu, index);
1757         flush_warnings(warn);
1758         return ret;
1759 }
1760 EXPORT_SYMBOL(dquot_alloc_inode);
1761 
1762 /*
1763  * Convert in-memory reserved quotas to real consumed quotas
1764  */
1765 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1766 {
1767         struct dquot **dquots;
1768         int cnt, index;
1769 
1770         if (!dquot_active(inode)) {
1771                 spin_lock(&inode->i_lock);
1772                 *inode_reserved_space(inode) -= number;
1773                 __inode_add_bytes(inode, number);
1774                 spin_unlock(&inode->i_lock);
1775                 return 0;
1776         }
1777 
1778         dquots = i_dquot(inode);
1779         index = srcu_read_lock(&dquot_srcu);
1780         spin_lock(&inode->i_lock);
1781         /* Claim reserved quotas to allocated quotas */
1782         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1783                 if (dquots[cnt]) {
1784                         struct dquot *dquot = dquots[cnt];
1785 
1786                         spin_lock(&dquot->dq_dqb_lock);
1787                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
1788                                 number = dquot->dq_dqb.dqb_rsvspace;
1789                         dquot->dq_dqb.dqb_curspace += number;
1790                         dquot->dq_dqb.dqb_rsvspace -= number;
1791                         spin_unlock(&dquot->dq_dqb_lock);
1792                 }
1793         }
1794         /* Update inode bytes */
1795         *inode_reserved_space(inode) -= number;
1796         __inode_add_bytes(inode, number);
1797         spin_unlock(&inode->i_lock);
1798         mark_all_dquot_dirty(dquots);
1799         srcu_read_unlock(&dquot_srcu, index);
1800         return 0;
1801 }
1802 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1803 
1804 /*
1805  * Convert allocated space back to in-memory reserved quotas
1806  */
1807 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1808 {
1809         struct dquot **dquots;
1810         int cnt, index;
1811 
1812         if (!dquot_active(inode)) {
1813                 spin_lock(&inode->i_lock);
1814                 *inode_reserved_space(inode) += number;
1815                 __inode_sub_bytes(inode, number);
1816                 spin_unlock(&inode->i_lock);
1817                 return;
1818         }
1819 
1820         dquots = i_dquot(inode);
1821         index = srcu_read_lock(&dquot_srcu);
1822         spin_lock(&inode->i_lock);
1823         /* Claim reserved quotas to allocated quotas */
1824         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1825                 if (dquots[cnt]) {
1826                         struct dquot *dquot = dquots[cnt];
1827 
1828                         spin_lock(&dquot->dq_dqb_lock);
1829                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1830                                 number = dquot->dq_dqb.dqb_curspace;
1831                         dquot->dq_dqb.dqb_rsvspace += number;
1832                         dquot->dq_dqb.dqb_curspace -= number;
1833                         spin_unlock(&dquot->dq_dqb_lock);
1834                 }
1835         }
1836         /* Update inode bytes */
1837         *inode_reserved_space(inode) += number;
1838         __inode_sub_bytes(inode, number);
1839         spin_unlock(&inode->i_lock);
1840         mark_all_dquot_dirty(dquots);
1841         srcu_read_unlock(&dquot_srcu, index);
1842         return;
1843 }
1844 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1845 
1846 /*
1847  * This operation can block, but only after everything is updated
1848  */
1849 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1850 {
1851         unsigned int cnt;
1852         struct dquot_warn warn[MAXQUOTAS];
1853         struct dquot **dquots;
1854         int reserve = flags & DQUOT_SPACE_RESERVE, index;
1855 
1856         if (!dquot_active(inode)) {
1857                 if (reserve) {
1858                         spin_lock(&inode->i_lock);
1859                         *inode_reserved_space(inode) -= number;
1860                         spin_unlock(&inode->i_lock);
1861                 } else {
1862                         inode_sub_bytes(inode, number);
1863                 }
1864                 return;
1865         }
1866 
1867         dquots = i_dquot(inode);
1868         index = srcu_read_lock(&dquot_srcu);
1869         spin_lock(&inode->i_lock);
1870         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1871                 int wtype;
1872 
1873                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1874                 if (!dquots[cnt])
1875                         continue;
1876                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1877                 wtype = info_bdq_free(dquots[cnt], number);
1878                 if (wtype != QUOTA_NL_NOWARN)
1879                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1880                 if (reserve)
1881                         dquot_free_reserved_space(dquots[cnt], number);
1882                 else
1883                         dquot_decr_space(dquots[cnt], number);
1884                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1885         }
1886         if (reserve)
1887                 *inode_reserved_space(inode) -= number;
1888         else
1889                 __inode_sub_bytes(inode, number);
1890         spin_unlock(&inode->i_lock);
1891 
1892         if (reserve)
1893                 goto out_unlock;
1894         mark_all_dquot_dirty(dquots);
1895 out_unlock:
1896         srcu_read_unlock(&dquot_srcu, index);
1897         flush_warnings(warn);
1898 }
1899 EXPORT_SYMBOL(__dquot_free_space);
1900 
1901 /*
1902  * This operation can block, but only after everything is updated
1903  */
1904 void dquot_free_inode(struct inode *inode)
1905 {
1906         unsigned int cnt;
1907         struct dquot_warn warn[MAXQUOTAS];
1908         struct dquot * const *dquots;
1909         int index;
1910 
1911         if (!dquot_active(inode))
1912                 return;
1913 
1914         dquots = i_dquot(inode);
1915         index = srcu_read_lock(&dquot_srcu);
1916         spin_lock(&inode->i_lock);
1917         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1918                 int wtype;
1919 
1920                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1921                 if (!dquots[cnt])
1922                         continue;
1923                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1924                 wtype = info_idq_free(dquots[cnt], 1);
1925                 if (wtype != QUOTA_NL_NOWARN)
1926                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1927                 dquot_decr_inodes(dquots[cnt], 1);
1928                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1929         }
1930         spin_unlock(&inode->i_lock);
1931         mark_all_dquot_dirty(dquots);
1932         srcu_read_unlock(&dquot_srcu, index);
1933         flush_warnings(warn);
1934 }
1935 EXPORT_SYMBOL(dquot_free_inode);
1936 
1937 /*
1938  * Transfer the number of inode and blocks from one diskquota to an other.
1939  * On success, dquot references in transfer_to are consumed and references
1940  * to original dquots that need to be released are placed there. On failure,
1941  * references are kept untouched.
1942  *
1943  * This operation can block, but only after everything is updated
1944  * A transaction must be started when entering this function.
1945  *
1946  * We are holding reference on transfer_from & transfer_to, no need to
1947  * protect them by srcu_read_lock().
1948  */
1949 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1950 {
1951         qsize_t cur_space;
1952         qsize_t rsv_space = 0;
1953         qsize_t inode_usage = 1;
1954         struct dquot *transfer_from[MAXQUOTAS] = {};
1955         int cnt, ret = 0;
1956         char is_valid[MAXQUOTAS] = {};
1957         struct dquot_warn warn_to[MAXQUOTAS];
1958         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1959         struct dquot_warn warn_from_space[MAXQUOTAS];
1960 
1961         if (IS_NOQUOTA(inode))
1962                 return 0;
1963 
1964         if (inode->i_sb->dq_op->get_inode_usage) {
1965                 ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
1966                 if (ret)
1967                         return ret;
1968         }
1969 
1970         /* Initialize the arrays */
1971         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1972                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
1973                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
1974                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
1975         }
1976 
1977         spin_lock(&dq_data_lock);
1978         spin_lock(&inode->i_lock);
1979         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1980                 spin_unlock(&inode->i_lock);
1981                 spin_unlock(&dq_data_lock);
1982                 return 0;
1983         }
1984         cur_space = __inode_get_bytes(inode);
1985         rsv_space = __inode_get_rsv_space(inode);
1986         /*
1987          * Build the transfer_from list, check limits, and update usage in
1988          * the target structures.
1989          */
1990         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1991                 /*
1992                  * Skip changes for same uid or gid or for turned off quota-type.
1993                  */
1994                 if (!transfer_to[cnt])
1995                         continue;
1996                 /* Avoid races with quotaoff() */
1997                 if (!sb_has_quota_active(inode->i_sb, cnt))
1998                         continue;
1999                 is_valid[cnt] = 1;
2000                 transfer_from[cnt] = i_dquot(inode)[cnt];
2001                 ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
2002                                        &warn_to[cnt]);
2003                 if (ret)
2004                         goto over_quota;
2005                 ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space,
2006                                       DQUOT_SPACE_WARN, &warn_to[cnt]);
2007                 if (ret) {
2008                         spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2009                         dquot_decr_inodes(transfer_to[cnt], inode_usage);
2010                         spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2011                         goto over_quota;
2012                 }
2013         }
2014 
2015         /* Decrease usage for source structures and update quota pointers */
2016         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2017                 if (!is_valid[cnt])
2018                         continue;
2019                 /* Due to IO error we might not have transfer_from[] structure */
2020                 if (transfer_from[cnt]) {
2021                         int wtype;
2022 
2023                         spin_lock(&transfer_from[cnt]->dq_dqb_lock);
2024                         wtype = info_idq_free(transfer_from[cnt], inode_usage);
2025                         if (wtype != QUOTA_NL_NOWARN)
2026                                 prepare_warning(&warn_from_inodes[cnt],
2027                                                 transfer_from[cnt], wtype);
2028                         wtype = info_bdq_free(transfer_from[cnt],
2029                                               cur_space + rsv_space);
2030                         if (wtype != QUOTA_NL_NOWARN)
2031                                 prepare_warning(&warn_from_space[cnt],
2032                                                 transfer_from[cnt], wtype);
2033                         dquot_decr_inodes(transfer_from[cnt], inode_usage);
2034                         dquot_decr_space(transfer_from[cnt], cur_space);
2035                         dquot_free_reserved_space(transfer_from[cnt],
2036                                                   rsv_space);
2037                         spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
2038                 }
2039                 i_dquot(inode)[cnt] = transfer_to[cnt];
2040         }
2041         spin_unlock(&inode->i_lock);
2042         spin_unlock(&dq_data_lock);
2043 
2044         mark_all_dquot_dirty(transfer_from);
2045         mark_all_dquot_dirty(transfer_to);
2046         flush_warnings(warn_to);
2047         flush_warnings(warn_from_inodes);
2048         flush_warnings(warn_from_space);
2049         /* Pass back references to put */
2050         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2051                 if (is_valid[cnt])
2052                         transfer_to[cnt] = transfer_from[cnt];
2053         return 0;
2054 over_quota:
2055         /* Back out changes we already did */
2056         for (cnt--; cnt >= 0; cnt--) {
2057                 if (!is_valid[cnt])
2058                         continue;
2059                 spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2060                 dquot_decr_inodes(transfer_to[cnt], inode_usage);
2061                 dquot_decr_space(transfer_to[cnt], cur_space);
2062                 dquot_free_reserved_space(transfer_to[cnt], rsv_space);
2063                 spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2064         }
2065         spin_unlock(&inode->i_lock);
2066         spin_unlock(&dq_data_lock);
2067         flush_warnings(warn_to);
2068         return ret;
2069 }
2070 EXPORT_SYMBOL(__dquot_transfer);
2071 
2072 /* Wrapper for transferring ownership of an inode for uid/gid only
2073  * Called from FSXXX_setattr()
2074  */
2075 int dquot_transfer(struct inode *inode, struct iattr *iattr)
2076 {
2077         struct dquot *transfer_to[MAXQUOTAS] = {};
2078         struct dquot *dquot;
2079         struct super_block *sb = inode->i_sb;
2080         int ret;
2081 
2082         if (!dquot_active(inode))
2083                 return 0;
2084 
2085         if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
2086                 dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
2087                 if (IS_ERR(dquot)) {
2088                         if (PTR_ERR(dquot) != -ESRCH) {
2089                                 ret = PTR_ERR(dquot);
2090                                 goto out_put;
2091                         }
2092                         dquot = NULL;
2093                 }
2094                 transfer_to[USRQUOTA] = dquot;
2095         }
2096         if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
2097                 dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
2098                 if (IS_ERR(dquot)) {
2099                         if (PTR_ERR(dquot) != -ESRCH) {
2100                                 ret = PTR_ERR(dquot);
2101                                 goto out_put;
2102                         }
2103                         dquot = NULL;
2104                 }
2105                 transfer_to[GRPQUOTA] = dquot;
2106         }
2107         ret = __dquot_transfer(inode, transfer_to);
2108 out_put:
2109         dqput_all(transfer_to);
2110         return ret;
2111 }
2112 EXPORT_SYMBOL(dquot_transfer);
2113 
2114 /*
2115  * Write info of quota file to disk
2116  */
2117 int dquot_commit_info(struct super_block *sb, int type)
2118 {
2119         struct quota_info *dqopt = sb_dqopt(sb);
2120 
2121         return dqopt->ops[type]->write_file_info(sb, type);
2122 }
2123 EXPORT_SYMBOL(dquot_commit_info);
2124 
2125 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
2126 {
2127         struct quota_info *dqopt = sb_dqopt(sb);
2128 
2129         if (!sb_has_quota_active(sb, qid->type))
2130                 return -ESRCH;
2131         if (!dqopt->ops[qid->type]->get_next_id)
2132                 return -ENOSYS;
2133         return dqopt->ops[qid->type]->get_next_id(sb, qid);
2134 }
2135 EXPORT_SYMBOL(dquot_get_next_id);
2136 
2137 /*
2138  * Definitions of diskquota operations.
2139  */
2140 const struct dquot_operations dquot_operations = {
2141         .write_dquot    = dquot_commit,
2142         .acquire_dquot  = dquot_acquire,
2143         .release_dquot  = dquot_release,
2144         .mark_dirty     = dquot_mark_dquot_dirty,
2145         .write_info     = dquot_commit_info,
2146         .alloc_dquot    = dquot_alloc,
2147         .destroy_dquot  = dquot_destroy,
2148         .get_next_id    = dquot_get_next_id,
2149 };
2150 EXPORT_SYMBOL(dquot_operations);
2151 
2152 /*
2153  * Generic helper for ->open on filesystems supporting disk quotas.
2154  */
2155 int dquot_file_open(struct inode *inode, struct file *file)
2156 {
2157         int error;
2158 
2159         error = generic_file_open(inode, file);
2160         if (!error && (file->f_mode & FMODE_WRITE))
2161                 error = dquot_initialize(inode);
2162         return error;
2163 }
2164 EXPORT_SYMBOL(dquot_file_open);
2165 
2166 static void vfs_cleanup_quota_inode(struct super_block *sb, int type)
2167 {
2168         struct quota_info *dqopt = sb_dqopt(sb);
2169         struct inode *inode = dqopt->files[type];
2170 
2171         if (!inode)
2172                 return;
2173         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2174                 inode_lock(inode);
2175                 inode->i_flags &= ~S_NOQUOTA;
2176                 inode_unlock(inode);
2177         }
2178         dqopt->files[type] = NULL;
2179         iput(inode);
2180 }
2181 
2182 /*
2183  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2184  */
2185 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2186 {
2187         int cnt;
2188         struct quota_info *dqopt = sb_dqopt(sb);
2189 
2190         /* s_umount should be held in exclusive mode */
2191         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2192                 up_read(&sb->s_umount);
2193 
2194         /* Cannot turn off usage accounting without turning off limits, or
2195          * suspend quotas and simultaneously turn quotas off. */
2196         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2197             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2198             DQUOT_USAGE_ENABLED)))
2199                 return -EINVAL;
2200 
2201         /*
2202          * Skip everything if there's nothing to do. We have to do this because
2203          * sometimes we are called when fill_super() failed and calling
2204          * sync_fs() in such cases does no good.
2205          */
2206         if (!sb_any_quota_loaded(sb))
2207                 return 0;
2208 
2209         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2210                 if (type != -1 && cnt != type)
2211                         continue;
2212                 if (!sb_has_quota_loaded(sb, cnt))
2213                         continue;
2214 
2215                 if (flags & DQUOT_SUSPENDED) {
2216                         spin_lock(&dq_state_lock);
2217                         dqopt->flags |=
2218                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2219                         spin_unlock(&dq_state_lock);
2220                 } else {
2221                         spin_lock(&dq_state_lock);
2222                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2223                         /* Turning off suspended quotas? */
2224                         if (!sb_has_quota_loaded(sb, cnt) &&
2225                             sb_has_quota_suspended(sb, cnt)) {
2226                                 dqopt->flags &= ~dquot_state_flag(
2227                                                         DQUOT_SUSPENDED, cnt);
2228                                 spin_unlock(&dq_state_lock);
2229                                 vfs_cleanup_quota_inode(sb, cnt);
2230                                 continue;
2231                         }
2232                         spin_unlock(&dq_state_lock);
2233                 }
2234 
2235                 /* We still have to keep quota loaded? */
2236                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2237                         continue;
2238 
2239                 /* Note: these are blocking operations */
2240                 drop_dquot_ref(sb, cnt);
2241                 invalidate_dquots(sb, cnt);
2242                 /*
2243                  * Now all dquots should be invalidated, all writes done so we
2244                  * should be only users of the info. No locks needed.
2245                  */
2246                 if (info_dirty(&dqopt->info[cnt]))
2247                         sb->dq_op->write_info(sb, cnt);
2248                 if (dqopt->ops[cnt]->free_file_info)
2249                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2250                 put_quota_format(dqopt->info[cnt].dqi_format);
2251                 dqopt->info[cnt].dqi_flags = 0;
2252                 dqopt->info[cnt].dqi_igrace = 0;
2253                 dqopt->info[cnt].dqi_bgrace = 0;
2254                 dqopt->ops[cnt] = NULL;
2255         }
2256 
2257         /* Skip syncing and setting flags if quota files are hidden */
2258         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2259                 goto put_inodes;
2260 
2261         /* Sync the superblock so that buffers with quota data are written to
2262          * disk (and so userspace sees correct data afterwards). */
2263         if (sb->s_op->sync_fs)
2264                 sb->s_op->sync_fs(sb, 1);
2265         sync_blockdev(sb->s_bdev);
2266         /* Now the quota files are just ordinary files and we can set the
2267          * inode flags back. Moreover we discard the pagecache so that
2268          * userspace sees the writes we did bypassing the pagecache. We
2269          * must also discard the blockdev buffers so that we see the
2270          * changes done by userspace on the next quotaon() */
2271         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2272                 if (!sb_has_quota_loaded(sb, cnt) && dqopt->files[cnt]) {
2273                         inode_lock(dqopt->files[cnt]);
2274                         truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
2275                         inode_unlock(dqopt->files[cnt]);
2276                 }
2277         if (sb->s_bdev)
2278                 invalidate_bdev(sb->s_bdev);
2279 put_inodes:
2280         /* We are done when suspending quotas */
2281         if (flags & DQUOT_SUSPENDED)
2282                 return 0;
2283 
2284         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2285                 if (!sb_has_quota_loaded(sb, cnt))
2286                         vfs_cleanup_quota_inode(sb, cnt);
2287         return 0;
2288 }
2289 EXPORT_SYMBOL(dquot_disable);
2290 
2291 int dquot_quota_off(struct super_block *sb, int type)
2292 {
2293         return dquot_disable(sb, type,
2294                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2295 }
2296 EXPORT_SYMBOL(dquot_quota_off);
2297 
2298 /*
2299  *      Turn quotas on on a device
2300  */
2301 
2302 static int vfs_setup_quota_inode(struct inode *inode, int type)
2303 {
2304         struct super_block *sb = inode->i_sb;
2305         struct quota_info *dqopt = sb_dqopt(sb);
2306 
2307         if (!S_ISREG(inode->i_mode))
2308                 return -EACCES;
2309         if (IS_RDONLY(inode))
2310                 return -EROFS;
2311         if (sb_has_quota_loaded(sb, type))
2312                 return -EBUSY;
2313 
2314         dqopt->files[type] = igrab(inode);
2315         if (!dqopt->files[type])
2316                 return -EIO;
2317         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2318                 /* We don't want quota and atime on quota files (deadlocks
2319                  * possible) Also nobody should write to the file - we use
2320                  * special IO operations which ignore the immutable bit. */
2321                 inode_lock(inode);
2322                 inode->i_flags |= S_NOQUOTA;
2323                 inode_unlock(inode);
2324                 /*
2325                  * When S_NOQUOTA is set, remove dquot references as no more
2326                  * references can be added
2327                  */
2328                 __dquot_drop(inode);
2329         }
2330         return 0;
2331 }
2332 
2333 int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,
2334         unsigned int flags)
2335 {
2336         struct quota_format_type *fmt = find_quota_format(format_id);
2337         struct quota_info *dqopt = sb_dqopt(sb);
2338         int error;
2339 
2340         /* Just unsuspend quotas? */
2341         BUG_ON(flags & DQUOT_SUSPENDED);
2342         /* s_umount should be held in exclusive mode */
2343         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2344                 up_read(&sb->s_umount);
2345 
2346         if (!fmt)
2347                 return -ESRCH;
2348         if (!sb->s_op->quota_write || !sb->s_op->quota_read ||
2349             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2350                 error = -EINVAL;
2351                 goto out_fmt;
2352         }
2353         /* Filesystems outside of init_user_ns not yet supported */
2354         if (sb->s_user_ns != &init_user_ns) {
2355                 error = -EINVAL;
2356                 goto out_fmt;
2357         }
2358         /* Usage always has to be set... */
2359         if (!(flags & DQUOT_USAGE_ENABLED)) {
2360                 error = -EINVAL;
2361                 goto out_fmt;
2362         }
2363         if (sb_has_quota_loaded(sb, type)) {
2364                 error = -EBUSY;
2365                 goto out_fmt;
2366         }
2367 
2368         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2369                 /* As we bypass the pagecache we must now flush all the
2370                  * dirty data and invalidate caches so that kernel sees
2371                  * changes from userspace. It is not enough to just flush
2372                  * the quota file since if blocksize < pagesize, invalidation
2373                  * of the cache could fail because of other unrelated dirty
2374                  * data */
2375                 sync_filesystem(sb);
2376                 invalidate_bdev(sb->s_bdev);
2377         }
2378 
2379         error = -EINVAL;
2380         if (!fmt->qf_ops->check_quota_file(sb, type))
2381                 goto out_fmt;
2382 
2383         dqopt->ops[type] = fmt->qf_ops;
2384         dqopt->info[type].dqi_format = fmt;
2385         dqopt->info[type].dqi_fmt_id = format_id;
2386         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2387         error = dqopt->ops[type]->read_file_info(sb, type);
2388         if (error < 0)
2389                 goto out_fmt;
2390         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2391                 spin_lock(&dq_data_lock);
2392                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2393                 spin_unlock(&dq_data_lock);
2394         }
2395         spin_lock(&dq_state_lock);
2396         dqopt->flags |= dquot_state_flag(flags, type);
2397         spin_unlock(&dq_state_lock);
2398 
2399         error = add_dquot_ref(sb, type);
2400         if (error)
2401                 dquot_disable(sb, type, flags);
2402 
2403         return error;
2404 out_fmt:
2405         put_quota_format(fmt);
2406 
2407         return error;
2408 }
2409 EXPORT_SYMBOL(dquot_load_quota_sb);
2410 
2411 /*
2412  * More powerful function for turning on quotas on given quota inode allowing
2413  * setting of individual quota flags
2414  */
2415 int dquot_load_quota_inode(struct inode *inode, int type, int format_id,
2416         unsigned int flags)
2417 {
2418         int err;
2419 
2420         err = vfs_setup_quota_inode(inode, type);
2421         if (err < 0)
2422                 return err;
2423         err = dquot_load_quota_sb(inode->i_sb, type, format_id, flags);
2424         if (err < 0)
2425                 vfs_cleanup_quota_inode(inode->i_sb, type);
2426         return err;
2427 }
2428 EXPORT_SYMBOL(dquot_load_quota_inode);
2429 
2430 /* Reenable quotas on remount RW */
2431 int dquot_resume(struct super_block *sb, int type)
2432 {
2433         struct quota_info *dqopt = sb_dqopt(sb);
2434         int ret = 0, cnt;
2435         unsigned int flags;
2436 
2437         /* s_umount should be held in exclusive mode */
2438         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2439                 up_read(&sb->s_umount);
2440 
2441         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2442                 if (type != -1 && cnt != type)
2443                         continue;
2444                 if (!sb_has_quota_suspended(sb, cnt))
2445                         continue;
2446 
2447                 spin_lock(&dq_state_lock);
2448                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2449                                                         DQUOT_LIMITS_ENABLED,
2450                                                         cnt);
2451                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2452                 spin_unlock(&dq_state_lock);
2453 
2454                 flags = dquot_generic_flag(flags, cnt);
2455                 ret = dquot_load_quota_sb(sb, cnt, dqopt->info[cnt].dqi_fmt_id,
2456                                           flags);
2457                 if (ret < 0)
2458                         vfs_cleanup_quota_inode(sb, cnt);
2459         }
2460 
2461         return ret;
2462 }
2463 EXPORT_SYMBOL(dquot_resume);
2464 
2465 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2466                    const struct path *path)
2467 {
2468         int error = security_quota_on(path->dentry);
2469         if (error)
2470                 return error;
2471         /* Quota file not on the same filesystem? */
2472         if (path->dentry->d_sb != sb)
2473                 error = -EXDEV;
2474         else
2475                 error = dquot_load_quota_inode(d_inode(path->dentry), type,
2476                                              format_id, DQUOT_USAGE_ENABLED |
2477                                              DQUOT_LIMITS_ENABLED);
2478         return error;
2479 }
2480 EXPORT_SYMBOL(dquot_quota_on);
2481 
2482 /*
2483  * This function is used when filesystem needs to initialize quotas
2484  * during mount time.
2485  */
2486 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2487                 int format_id, int type)
2488 {
2489         struct dentry *dentry;
2490         int error;
2491 
2492         dentry = lookup_positive_unlocked(qf_name, sb->s_root, strlen(qf_name));
2493         if (IS_ERR(dentry))
2494                 return PTR_ERR(dentry);
2495 
2496         error = security_quota_on(dentry);
2497         if (!error)
2498                 error = dquot_load_quota_inode(d_inode(dentry), type, format_id,
2499                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2500 
2501         dput(dentry);
2502         return error;
2503 }
2504 EXPORT_SYMBOL(dquot_quota_on_mount);
2505 
2506 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2507 {
2508         int ret;
2509         int type;
2510         struct quota_info *dqopt = sb_dqopt(sb);
2511 
2512         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2513                 return -ENOSYS;
2514         /* Accounting cannot be turned on while fs is mounted */
2515         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2516         if (!flags)
2517                 return -EINVAL;
2518         for (type = 0; type < MAXQUOTAS; type++) {
2519                 if (!(flags & qtype_enforce_flag(type)))
2520                         continue;
2521                 /* Can't enforce without accounting */
2522                 if (!sb_has_quota_usage_enabled(sb, type)) {
2523                         ret = -EINVAL;
2524                         goto out_err;
2525                 }
2526                 if (sb_has_quota_limits_enabled(sb, type)) {
2527                         ret = -EBUSY;
2528                         goto out_err;
2529                 }
2530                 spin_lock(&dq_state_lock);
2531                 dqopt->flags |= dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2532                 spin_unlock(&dq_state_lock);
2533         }
2534         return 0;
2535 out_err:
2536         /* Backout enforcement enablement we already did */
2537         for (type--; type >= 0; type--)  {
2538                 if (flags & qtype_enforce_flag(type))
2539                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2540         }
2541         /* Error code translation for better compatibility with XFS */
2542         if (ret == -EBUSY)
2543                 ret = -EEXIST;
2544         return ret;
2545 }
2546 
2547 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2548 {
2549         int ret;
2550         int type;
2551         struct quota_info *dqopt = sb_dqopt(sb);
2552 
2553         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2554                 return -ENOSYS;
2555         /*
2556          * We don't support turning off accounting via quotactl. In principle
2557          * quota infrastructure can do this but filesystems don't expect
2558          * userspace to be able to do it.
2559          */
2560         if (flags &
2561                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2562                 return -EOPNOTSUPP;
2563 
2564         /* Filter out limits not enabled */
2565         for (type = 0; type < MAXQUOTAS; type++)
2566                 if (!sb_has_quota_limits_enabled(sb, type))
2567                         flags &= ~qtype_enforce_flag(type);
2568         /* Nothing left? */
2569         if (!flags)
2570                 return -EEXIST;
2571         for (type = 0; type < MAXQUOTAS; type++) {
2572                 if (flags & qtype_enforce_flag(type)) {
2573                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2574                         if (ret < 0)
2575                                 goto out_err;
2576                 }
2577         }
2578         return 0;
2579 out_err:
2580         /* Backout enforcement disabling we already did */
2581         for (type--; type >= 0; type--)  {
2582                 if (flags & qtype_enforce_flag(type)) {
2583                         spin_lock(&dq_state_lock);
2584                         dqopt->flags |=
2585                                 dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2586                         spin_unlock(&dq_state_lock);
2587                 }
2588         }
2589         return ret;
2590 }
2591 
2592 /* Generic routine for getting common part of quota structure */
2593 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2594 {
2595         struct mem_dqblk *dm = &dquot->dq_dqb;
2596 
2597         memset(di, 0, sizeof(*di));
2598         spin_lock(&dquot->dq_dqb_lock);
2599         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2600         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2601         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2602         di->d_ino_softlimit = dm->dqb_isoftlimit;
2603         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2604         di->d_ino_count = dm->dqb_curinodes;
2605         di->d_spc_timer = dm->dqb_btime;
2606         di->d_ino_timer = dm->dqb_itime;
2607         spin_unlock(&dquot->dq_dqb_lock);
2608 }
2609 
2610 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2611                     struct qc_dqblk *di)
2612 {
2613         struct dquot *dquot;
2614 
2615         dquot = dqget(sb, qid);
2616         if (IS_ERR(dquot))
2617                 return PTR_ERR(dquot);
2618         do_get_dqblk(dquot, di);
2619         dqput(dquot);
2620 
2621         return 0;
2622 }
2623 EXPORT_SYMBOL(dquot_get_dqblk);
2624 
2625 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2626                          struct qc_dqblk *di)
2627 {
2628         struct dquot *dquot;
2629         int err;
2630 
2631         if (!sb->dq_op->get_next_id)
2632                 return -ENOSYS;
2633         err = sb->dq_op->get_next_id(sb, qid);
2634         if (err < 0)
2635                 return err;
2636         dquot = dqget(sb, *qid);
2637         if (IS_ERR(dquot))
2638                 return PTR_ERR(dquot);
2639         do_get_dqblk(dquot, di);
2640         dqput(dquot);
2641 
2642         return 0;
2643 }
2644 EXPORT_SYMBOL(dquot_get_next_dqblk);
2645 
2646 #define VFS_QC_MASK \
2647         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2648          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2649          QC_SPC_TIMER | QC_INO_TIMER)
2650 
2651 /* Generic routine for setting common part of quota structure */
2652 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2653 {
2654         struct mem_dqblk *dm = &dquot->dq_dqb;
2655         int check_blim = 0, check_ilim = 0;
2656         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2657 
2658         if (di->d_fieldmask & ~VFS_QC_MASK)
2659                 return -EINVAL;
2660 
2661         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2662              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2663             ((di->d_fieldmask & QC_SPC_HARD) &&
2664              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2665             ((di->d_fieldmask & QC_INO_SOFT) &&
2666              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2667             ((di->d_fieldmask & QC_INO_HARD) &&
2668              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2669                 return -ERANGE;
2670 
2671         spin_lock(&dquot->dq_dqb_lock);
2672         if (di->d_fieldmask & QC_SPACE) {
2673                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2674                 check_blim = 1;
2675                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2676         }
2677 
2678         if (di->d_fieldmask & QC_SPC_SOFT)
2679                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2680         if (di->d_fieldmask & QC_SPC_HARD)
2681                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2682         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2683                 check_blim = 1;
2684                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2685         }
2686 
2687         if (di->d_fieldmask & QC_INO_COUNT) {
2688                 dm->dqb_curinodes = di->d_ino_count;
2689                 check_ilim = 1;
2690                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2691         }
2692 
2693         if (di->d_fieldmask & QC_INO_SOFT)
2694                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2695         if (di->d_fieldmask & QC_INO_HARD)
2696                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2697         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2698                 check_ilim = 1;
2699                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2700         }
2701 
2702         if (di->d_fieldmask & QC_SPC_TIMER) {
2703                 dm->dqb_btime = di->d_spc_timer;
2704                 check_blim = 1;
2705                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2706         }
2707 
2708         if (di->d_fieldmask & QC_INO_TIMER) {
2709                 dm->dqb_itime = di->d_ino_timer;
2710                 check_ilim = 1;
2711                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2712         }
2713 
2714         if (check_blim) {
2715                 if (!dm->dqb_bsoftlimit ||
2716                     dm->dqb_curspace + dm->dqb_rsvspace <= dm->dqb_bsoftlimit) {
2717                         dm->dqb_btime = 0;
2718                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2719                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2720                         /* Set grace only if user hasn't provided his own... */
2721                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2722         }
2723         if (check_ilim) {
2724                 if (!dm->dqb_isoftlimit ||
2725                     dm->dqb_curinodes <= dm->dqb_isoftlimit) {
2726                         dm->dqb_itime = 0;
2727                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2728                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2729                         /* Set grace only if user hasn't provided his own... */
2730                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2731         }
2732         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2733             dm->dqb_isoftlimit)
2734                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2735         else
2736                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2737         spin_unlock(&dquot->dq_dqb_lock);
2738         mark_dquot_dirty(dquot);
2739 
2740         return 0;
2741 }
2742 
2743 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2744                   struct qc_dqblk *di)
2745 {
2746         struct dquot *dquot;
2747         int rc;
2748 
2749         dquot = dqget(sb, qid);
2750         if (IS_ERR(dquot)) {
2751                 rc = PTR_ERR(dquot);
2752                 goto out;
2753         }
2754         rc = do_set_dqblk(dquot, di);
2755         dqput(dquot);
2756 out:
2757         return rc;
2758 }
2759 EXPORT_SYMBOL(dquot_set_dqblk);
2760 
2761 /* Generic routine for getting common part of quota file information */
2762 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2763 {
2764         struct mem_dqinfo *mi;
2765         struct qc_type_state *tstate;
2766         struct quota_info *dqopt = sb_dqopt(sb);
2767         int type;
2768 
2769         memset(state, 0, sizeof(*state));
2770         for (type = 0; type < MAXQUOTAS; type++) {
2771                 if (!sb_has_quota_active(sb, type))
2772                         continue;
2773                 tstate = state->s_state + type;
2774                 mi = sb_dqopt(sb)->info + type;
2775                 tstate->flags = QCI_ACCT_ENABLED;
2776                 spin_lock(&dq_data_lock);
2777                 if (mi->dqi_flags & DQF_SYS_FILE)
2778                         tstate->flags |= QCI_SYSFILE;
2779                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2780                         tstate->flags |= QCI_ROOT_SQUASH;
2781                 if (sb_has_quota_limits_enabled(sb, type))
2782                         tstate->flags |= QCI_LIMITS_ENFORCED;
2783                 tstate->spc_timelimit = mi->dqi_bgrace;
2784                 tstate->ino_timelimit = mi->dqi_igrace;
2785                 if (dqopt->files[type]) {
2786                         tstate->ino = dqopt->files[type]->i_ino;
2787                         tstate->blocks = dqopt->files[type]->i_blocks;
2788                 }
2789                 tstate->nextents = 1;   /* We don't know... */
2790                 spin_unlock(&dq_data_lock);
2791         }
2792         return 0;
2793 }
2794 EXPORT_SYMBOL(dquot_get_state);
2795 
2796 /* Generic routine for setting common part of quota file information */
2797 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2798 {
2799         struct mem_dqinfo *mi;
2800         int err = 0;
2801 
2802         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2803             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2804                 return -EINVAL;
2805         if (!sb_has_quota_active(sb, type))
2806                 return -ESRCH;
2807         mi = sb_dqopt(sb)->info + type;
2808         if (ii->i_fieldmask & QC_FLAGS) {
2809                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2810                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2811                         return -EINVAL;
2812         }
2813         spin_lock(&dq_data_lock);
2814         if (ii->i_fieldmask & QC_SPC_TIMER)
2815                 mi->dqi_bgrace = ii->i_spc_timelimit;
2816         if (ii->i_fieldmask & QC_INO_TIMER)
2817                 mi->dqi_igrace = ii->i_ino_timelimit;
2818         if (ii->i_fieldmask & QC_FLAGS) {
2819                 if (ii->i_flags & QCI_ROOT_SQUASH)
2820                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2821                 else
2822                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2823         }
2824         spin_unlock(&dq_data_lock);
2825         mark_info_dirty(sb, type);
2826         /* Force write to disk */
2827         sb->dq_op->write_info(sb, type);
2828         return err;
2829 }
2830 EXPORT_SYMBOL(dquot_set_dqinfo);
2831 
2832 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2833         .quota_enable   = dquot_quota_enable,
2834         .quota_disable  = dquot_quota_disable,
2835         .quota_sync     = dquot_quota_sync,
2836         .get_state      = dquot_get_state,
2837         .set_info       = dquot_set_dqinfo,
2838         .get_dqblk      = dquot_get_dqblk,
2839         .get_nextdqblk  = dquot_get_next_dqblk,
2840         .set_dqblk      = dquot_set_dqblk
2841 };
2842 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2843 
2844 static int do_proc_dqstats(struct ctl_table *table, int write,
2845                      void *buffer, size_t *lenp, loff_t *ppos)
2846 {
2847         unsigned int type = (unsigned long *)table->data - dqstats.stat;
2848         s64 value = percpu_counter_sum(&dqstats.counter[type]);
2849 
2850         /* Filter negative values for non-monotonic counters */
2851         if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
2852                           type == DQST_FREE_DQUOTS))
2853                 value = 0;
2854 
2855         /* Update global table */
2856         dqstats.stat[type] = value;
2857         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
2858 }
2859 
2860 static struct ctl_table fs_dqstats_table[] = {
2861         {
2862                 .procname       = "lookups",
2863                 .data           = &dqstats.stat[DQST_LOOKUPS],
2864                 .maxlen         = sizeof(unsigned long),
2865                 .mode           = 0444,
2866                 .proc_handler   = do_proc_dqstats,
2867         },
2868         {
2869                 .procname       = "drops",
2870                 .data           = &dqstats.stat[DQST_DROPS],
2871                 .maxlen         = sizeof(unsigned long),
2872                 .mode           = 0444,
2873                 .proc_handler   = do_proc_dqstats,
2874         },
2875         {
2876                 .procname       = "reads",
2877                 .data           = &dqstats.stat[DQST_READS],
2878                 .maxlen         = sizeof(unsigned long),
2879                 .mode           = 0444,
2880                 .proc_handler   = do_proc_dqstats,
2881         },
2882         {
2883                 .procname       = "writes",
2884                 .data           = &dqstats.stat[DQST_WRITES],
2885                 .maxlen         = sizeof(unsigned long),
2886                 .mode           = 0444,
2887                 .proc_handler   = do_proc_dqstats,
2888         },
2889         {
2890                 .procname       = "cache_hits",
2891                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2892                 .maxlen         = sizeof(unsigned long),
2893                 .mode           = 0444,
2894                 .proc_handler   = do_proc_dqstats,
2895         },
2896         {
2897                 .procname       = "allocated_dquots",
2898                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2899                 .maxlen         = sizeof(unsigned long),
2900                 .mode           = 0444,
2901                 .proc_handler   = do_proc_dqstats,
2902         },
2903         {
2904                 .procname       = "free_dquots",
2905                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2906                 .maxlen         = sizeof(unsigned long),
2907                 .mode           = 0444,
2908                 .proc_handler   = do_proc_dqstats,
2909         },
2910         {
2911                 .procname       = "syncs",
2912                 .data           = &dqstats.stat[DQST_SYNCS],
2913                 .maxlen         = sizeof(unsigned long),
2914                 .mode           = 0444,
2915                 .proc_handler   = do_proc_dqstats,
2916         },
2917 #ifdef CONFIG_PRINT_QUOTA_WARNING
2918         {
2919                 .procname       = "warnings",
2920                 .data           = &flag_print_warnings,
2921                 .maxlen         = sizeof(int),
2922                 .mode           = 0644,
2923                 .proc_handler   = proc_dointvec,
2924         },
2925 #endif
2926         { },
2927 };
2928 
2929 static struct ctl_table fs_table[] = {
2930         {
2931                 .procname       = "quota",
2932                 .mode           = 0555,
2933                 .child          = fs_dqstats_table,
2934         },
2935         { },
2936 };
2937 
2938 static struct ctl_table sys_table[] = {
2939         {
2940                 .procname       = "fs",
2941                 .mode           = 0555,
2942                 .child          = fs_table,
2943         },
2944         { },
2945 };
2946 
2947 static int __init dquot_init(void)
2948 {
2949         int i, ret;
2950         unsigned long nr_hash, order;
2951 
2952         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2953 
2954         register_sysctl_table(sys_table);
2955 
2956         dquot_cachep = kmem_cache_create("dquot",
2957                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2958                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2959                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2960                         NULL);
2961 
2962         order = 0;
2963         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_KERNEL, order);
2964         if (!dquot_hash)
2965                 panic("Cannot create dquot hash table");
2966 
2967         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2968                 ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
2969                 if (ret)
2970                         panic("Cannot create dquot stat counters");
2971         }
2972 
2973         /* Find power-of-two hlist_heads which can fit into allocation */
2974         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2975         dq_hash_bits = ilog2(nr_hash);
2976 
2977         nr_hash = 1UL << dq_hash_bits;
2978         dq_hash_mask = nr_hash - 1;
2979         for (i = 0; i < nr_hash; i++)
2980                 INIT_HLIST_HEAD(dquot_hash + i);
2981 
2982         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
2983                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
2984 
2985         if (register_shrinker(&dqcache_shrinker))
2986                 panic("Cannot register dquot shrinker");
2987 
2988         return 0;
2989 }
2990 fs_initcall(dquot_init);
2991 

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