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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 "../internal.h" /* ugh */
 82 
 83 #include <linux/uaccess.h>
 84 
 85 /*
 86  * There are five quota SMP locks:
 87  * * dq_list_lock protects all lists with quotas and quota formats.
 88  * * dquot->dq_dqb_lock protects data from dq_dqb
 89  * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
 90  *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
 91  *   dquot_transfer() can stabilize amount it transfers
 92  * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
 93  *   pointers in the inode
 94  * * dq_state_lock protects modifications of quota state (on quotaon and
 95  *   quotaoff) and readers who care about latest values take it as well.
 96  *
 97  * The spinlock ordering is hence:
 98  *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
 99  *   dq_list_lock > dq_state_lock
100  *
101  * Note that some things (eg. sb pointer, type, id) doesn't change during
102  * the life of the dquot structure and so needn't to be protected by a lock
103  *
104  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
105  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
106  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
107  * inode and before dropping dquot references to avoid use of dquots after
108  * they are freed. dq_data_lock is used to serialize the pointer setting and
109  * clearing operations.
110  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
111  * inode is a quota file). Functions adding pointers from inode to dquots have
112  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
113  * have to do all pointer modifications before dropping dq_data_lock. This makes
114  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
115  * then drops all pointers to dquots from an inode.
116  *
117  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
118  * memory (or space for it is being allocated) on the first dqget(), when it is
119  * being written out, and when it is being released on the last dqput(). The
120  * allocation and release operations are serialized by the dq_lock and by
121  * checking the use count in dquot_release().
122  *
123  * Lock ordering (including related VFS locks) is the following:
124  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
125  */
126 
127 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
129 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
130 EXPORT_SYMBOL(dq_data_lock);
131 DEFINE_STATIC_SRCU(dquot_srcu);
132 
133 static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
134 
135 void __quota_error(struct super_block *sb, const char *func,
136                    const char *fmt, ...)
137 {
138         if (printk_ratelimit()) {
139                 va_list args;
140                 struct va_format vaf;
141 
142                 va_start(args, fmt);
143 
144                 vaf.fmt = fmt;
145                 vaf.va = &args;
146 
147                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
148                        sb->s_id, func, &vaf);
149 
150                 va_end(args);
151         }
152 }
153 EXPORT_SYMBOL(__quota_error);
154 
155 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
156 static char *quotatypes[] = INITQFNAMES;
157 #endif
158 static struct quota_format_type *quota_formats; /* List of registered formats */
159 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
160 
161 /* SLAB cache for dquot structures */
162 static struct kmem_cache *dquot_cachep;
163 
164 int register_quota_format(struct quota_format_type *fmt)
165 {
166         spin_lock(&dq_list_lock);
167         fmt->qf_next = quota_formats;
168         quota_formats = fmt;
169         spin_unlock(&dq_list_lock);
170         return 0;
171 }
172 EXPORT_SYMBOL(register_quota_format);
173 
174 void unregister_quota_format(struct quota_format_type *fmt)
175 {
176         struct quota_format_type **actqf;
177 
178         spin_lock(&dq_list_lock);
179         for (actqf = &quota_formats; *actqf && *actqf != fmt;
180              actqf = &(*actqf)->qf_next)
181                 ;
182         if (*actqf)
183                 *actqf = (*actqf)->qf_next;
184         spin_unlock(&dq_list_lock);
185 }
186 EXPORT_SYMBOL(unregister_quota_format);
187 
188 static struct quota_format_type *find_quota_format(int id)
189 {
190         struct quota_format_type *actqf;
191 
192         spin_lock(&dq_list_lock);
193         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
194              actqf = actqf->qf_next)
195                 ;
196         if (!actqf || !try_module_get(actqf->qf_owner)) {
197                 int qm;
198 
199                 spin_unlock(&dq_list_lock);
200 
201                 for (qm = 0; module_names[qm].qm_fmt_id &&
202                              module_names[qm].qm_fmt_id != id; qm++)
203                         ;
204                 if (!module_names[qm].qm_fmt_id ||
205                     request_module(module_names[qm].qm_mod_name))
206                         return NULL;
207 
208                 spin_lock(&dq_list_lock);
209                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
210                      actqf = actqf->qf_next)
211                         ;
212                 if (actqf && !try_module_get(actqf->qf_owner))
213                         actqf = NULL;
214         }
215         spin_unlock(&dq_list_lock);
216         return actqf;
217 }
218 
219 static void put_quota_format(struct quota_format_type *fmt)
220 {
221         module_put(fmt->qf_owner);
222 }
223 
224 /*
225  * Dquot List Management:
226  * The quota code uses four lists for dquot management: the inuse_list,
227  * free_dquots, dqi_dirty_list, and dquot_hash[] array. A single dquot
228  * structure may be on some of those lists, depending on its current state.
229  *
230  * All dquots are placed to the end of inuse_list when first created, and this
231  * list is used for invalidate operation, which must look at every dquot.
232  *
233  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
234  * and this list is searched whenever we need an available dquot.  Dquots are
235  * removed from the list as soon as they are used again, and
236  * dqstats.free_dquots gives the number of dquots on the list. When
237  * dquot is invalidated it's completely released from memory.
238  *
239  * Dirty dquots are added to the dqi_dirty_list of quota_info when mark
240  * dirtied, and this list is searched when writing dirty dquots back to
241  * quota file. Note that some filesystems do dirty dquot tracking on their
242  * own (e.g. in a journal) and thus don't use dqi_dirty_list.
243  *
244  * Dquots with a specific identity (device, type and id) are placed on
245  * one of the dquot_hash[] hash chains. The provides an efficient search
246  * mechanism to locate a specific dquot.
247  */
248 
249 static LIST_HEAD(inuse_list);
250 static LIST_HEAD(free_dquots);
251 static unsigned int dq_hash_bits, dq_hash_mask;
252 static struct hlist_head *dquot_hash;
253 
254 struct dqstats dqstats;
255 EXPORT_SYMBOL(dqstats);
256 
257 static qsize_t inode_get_rsv_space(struct inode *inode);
258 static qsize_t __inode_get_rsv_space(struct inode *inode);
259 static int __dquot_initialize(struct inode *inode, int type);
260 
261 static inline unsigned int
262 hashfn(const struct super_block *sb, struct kqid qid)
263 {
264         unsigned int id = from_kqid(&init_user_ns, qid);
265         int type = qid.type;
266         unsigned long tmp;
267 
268         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
269         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
270 }
271 
272 /*
273  * Following list functions expect dq_list_lock to be held
274  */
275 static inline void insert_dquot_hash(struct dquot *dquot)
276 {
277         struct hlist_head *head;
278         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
279         hlist_add_head(&dquot->dq_hash, head);
280 }
281 
282 static inline void remove_dquot_hash(struct dquot *dquot)
283 {
284         hlist_del_init(&dquot->dq_hash);
285 }
286 
287 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
288                                 struct kqid qid)
289 {
290         struct hlist_node *node;
291         struct dquot *dquot;
292 
293         hlist_for_each (node, dquot_hash+hashent) {
294                 dquot = hlist_entry(node, struct dquot, dq_hash);
295                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
296                         return dquot;
297         }
298         return NULL;
299 }
300 
301 /* Add a dquot to the tail of the free list */
302 static inline void put_dquot_last(struct dquot *dquot)
303 {
304         list_add_tail(&dquot->dq_free, &free_dquots);
305         dqstats_inc(DQST_FREE_DQUOTS);
306 }
307 
308 static inline void remove_free_dquot(struct dquot *dquot)
309 {
310         if (list_empty(&dquot->dq_free))
311                 return;
312         list_del_init(&dquot->dq_free);
313         dqstats_dec(DQST_FREE_DQUOTS);
314 }
315 
316 static inline void put_inuse(struct dquot *dquot)
317 {
318         /* We add to the back of inuse list so we don't have to restart
319          * when traversing this list and we block */
320         list_add_tail(&dquot->dq_inuse, &inuse_list);
321         dqstats_inc(DQST_ALLOC_DQUOTS);
322 }
323 
324 static inline void remove_inuse(struct dquot *dquot)
325 {
326         dqstats_dec(DQST_ALLOC_DQUOTS);
327         list_del(&dquot->dq_inuse);
328 }
329 /*
330  * End of list functions needing dq_list_lock
331  */
332 
333 static void wait_on_dquot(struct dquot *dquot)
334 {
335         mutex_lock(&dquot->dq_lock);
336         mutex_unlock(&dquot->dq_lock);
337 }
338 
339 static inline int dquot_dirty(struct dquot *dquot)
340 {
341         return test_bit(DQ_MOD_B, &dquot->dq_flags);
342 }
343 
344 static inline int mark_dquot_dirty(struct dquot *dquot)
345 {
346         return dquot->dq_sb->dq_op->mark_dirty(dquot);
347 }
348 
349 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
350 int dquot_mark_dquot_dirty(struct dquot *dquot)
351 {
352         int ret = 1;
353 
354         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
355                 return 0;
356 
357         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
358                 return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
359 
360         /* If quota is dirty already, we don't have to acquire dq_list_lock */
361         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
362                 return 1;
363 
364         spin_lock(&dq_list_lock);
365         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
366                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
367                                 info[dquot->dq_id.type].dqi_dirty_list);
368                 ret = 0;
369         }
370         spin_unlock(&dq_list_lock);
371         return ret;
372 }
373 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
374 
375 /* Dirtify all the dquots - this can block when journalling */
376 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
377 {
378         int ret, err, cnt;
379 
380         ret = err = 0;
381         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
382                 if (dquot[cnt])
383                         /* Even in case of error we have to continue */
384                         ret = mark_dquot_dirty(dquot[cnt]);
385                 if (!err)
386                         err = ret;
387         }
388         return err;
389 }
390 
391 static inline void dqput_all(struct dquot **dquot)
392 {
393         unsigned int cnt;
394 
395         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
396                 dqput(dquot[cnt]);
397 }
398 
399 static inline int clear_dquot_dirty(struct dquot *dquot)
400 {
401         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
402                 return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
403 
404         spin_lock(&dq_list_lock);
405         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
406                 spin_unlock(&dq_list_lock);
407                 return 0;
408         }
409         list_del_init(&dquot->dq_dirty);
410         spin_unlock(&dq_list_lock);
411         return 1;
412 }
413 
414 void mark_info_dirty(struct super_block *sb, int type)
415 {
416         spin_lock(&dq_data_lock);
417         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
418         spin_unlock(&dq_data_lock);
419 }
420 EXPORT_SYMBOL(mark_info_dirty);
421 
422 /*
423  *      Read dquot from disk and alloc space for it
424  */
425 
426 int dquot_acquire(struct dquot *dquot)
427 {
428         int ret = 0, ret2 = 0;
429         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
430 
431         mutex_lock(&dquot->dq_lock);
432         if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
433                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
434                 if (ret < 0)
435                         goto out_iolock;
436         }
437         /* Make sure flags update is visible after dquot has been filled */
438         smp_mb__before_atomic();
439         set_bit(DQ_READ_B, &dquot->dq_flags);
440         /* Instantiate dquot if needed */
441         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
442                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
443                 /* Write the info if needed */
444                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
445                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
446                                         dquot->dq_sb, dquot->dq_id.type);
447                 }
448                 if (ret < 0)
449                         goto out_iolock;
450                 if (ret2 < 0) {
451                         ret = ret2;
452                         goto out_iolock;
453                 }
454         }
455         /*
456          * Make sure flags update is visible after on-disk struct has been
457          * allocated. Paired with smp_rmb() in dqget().
458          */
459         smp_mb__before_atomic();
460         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
461 out_iolock:
462         mutex_unlock(&dquot->dq_lock);
463         return ret;
464 }
465 EXPORT_SYMBOL(dquot_acquire);
466 
467 /*
468  *      Write dquot to disk
469  */
470 int dquot_commit(struct dquot *dquot)
471 {
472         int ret = 0;
473         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
474 
475         mutex_lock(&dquot->dq_lock);
476         if (!clear_dquot_dirty(dquot))
477                 goto out_lock;
478         /* Inactive dquot can be only if there was error during read/init
479          * => we have better not writing it */
480         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
481                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
482         else
483                 ret = -EIO;
484 out_lock:
485         mutex_unlock(&dquot->dq_lock);
486         return ret;
487 }
488 EXPORT_SYMBOL(dquot_commit);
489 
490 /*
491  *      Release dquot
492  */
493 int dquot_release(struct dquot *dquot)
494 {
495         int ret = 0, ret2 = 0;
496         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
497 
498         mutex_lock(&dquot->dq_lock);
499         /* Check whether we are not racing with some other dqget() */
500         if (dquot_is_busy(dquot))
501                 goto out_dqlock;
502         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
503                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
504                 /* Write the info */
505                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
506                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
507                                                 dquot->dq_sb, dquot->dq_id.type);
508                 }
509                 if (ret >= 0)
510                         ret = ret2;
511         }
512         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
513 out_dqlock:
514         mutex_unlock(&dquot->dq_lock);
515         return ret;
516 }
517 EXPORT_SYMBOL(dquot_release);
518 
519 void dquot_destroy(struct dquot *dquot)
520 {
521         kmem_cache_free(dquot_cachep, dquot);
522 }
523 EXPORT_SYMBOL(dquot_destroy);
524 
525 static inline void do_destroy_dquot(struct dquot *dquot)
526 {
527         dquot->dq_sb->dq_op->destroy_dquot(dquot);
528 }
529 
530 /* Invalidate all dquots on the list. Note that this function is called after
531  * quota is disabled and pointers from inodes removed so there cannot be new
532  * quota users. There can still be some users of quotas due to inodes being
533  * just deleted or pruned by prune_icache() (those are not attached to any
534  * list) or parallel quotactl call. We have to wait for such users.
535  */
536 static void invalidate_dquots(struct super_block *sb, int type)
537 {
538         struct dquot *dquot, *tmp;
539 
540 restart:
541         spin_lock(&dq_list_lock);
542         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
543                 if (dquot->dq_sb != sb)
544                         continue;
545                 if (dquot->dq_id.type != type)
546                         continue;
547                 /* Wait for dquot users */
548                 if (atomic_read(&dquot->dq_count)) {
549                         dqgrab(dquot);
550                         spin_unlock(&dq_list_lock);
551                         /*
552                          * Once dqput() wakes us up, we know it's time to free
553                          * the dquot.
554                          * IMPORTANT: we rely on the fact that there is always
555                          * at most one process waiting for dquot to free.
556                          * Otherwise dq_count would be > 1 and we would never
557                          * wake up.
558                          */
559                         wait_event(dquot_ref_wq,
560                                    atomic_read(&dquot->dq_count) == 1);
561                         dqput(dquot);
562                         /* At this moment dquot() need not exist (it could be
563                          * reclaimed by prune_dqcache(). Hence we must
564                          * restart. */
565                         goto restart;
566                 }
567                 /*
568                  * Quota now has no users and it has been written on last
569                  * dqput()
570                  */
571                 remove_dquot_hash(dquot);
572                 remove_free_dquot(dquot);
573                 remove_inuse(dquot);
574                 do_destroy_dquot(dquot);
575         }
576         spin_unlock(&dq_list_lock);
577 }
578 
579 /* Call callback for every active dquot on given filesystem */
580 int dquot_scan_active(struct super_block *sb,
581                       int (*fn)(struct dquot *dquot, unsigned long priv),
582                       unsigned long priv)
583 {
584         struct dquot *dquot, *old_dquot = NULL;
585         int ret = 0;
586 
587         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
588 
589         spin_lock(&dq_list_lock);
590         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
591                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
592                         continue;
593                 if (dquot->dq_sb != sb)
594                         continue;
595                 /* Now we have active dquot so we can just increase use count */
596                 atomic_inc(&dquot->dq_count);
597                 spin_unlock(&dq_list_lock);
598                 dqstats_inc(DQST_LOOKUPS);
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                         dqstats_inc(DQST_LOOKUPS);
654                         err = sb->dq_op->write_dquot(dquot);
655                         if (err) {
656                                 /*
657                                  * Clear dirty bit anyway to avoid infinite
658                                  * loop here.
659                                  */
660                                 clear_dquot_dirty(dquot);
661                                 if (!ret)
662                                         ret = err;
663                         }
664                         dqput(dquot);
665                         spin_lock(&dq_list_lock);
666                 }
667                 spin_unlock(&dq_list_lock);
668         }
669 
670         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
671                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
672                     && info_dirty(&dqopt->info[cnt]))
673                         sb->dq_op->write_info(sb, cnt);
674         dqstats_inc(DQST_SYNCS);
675 
676         return ret;
677 }
678 EXPORT_SYMBOL(dquot_writeback_dquots);
679 
680 /* Write all dquot structures to disk and make them visible from userspace */
681 int dquot_quota_sync(struct super_block *sb, int type)
682 {
683         struct quota_info *dqopt = sb_dqopt(sb);
684         int cnt;
685         int ret;
686 
687         ret = dquot_writeback_dquots(sb, type);
688         if (ret)
689                 return ret;
690         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
691                 return 0;
692 
693         /* This is not very clever (and fast) but currently I don't know about
694          * any other simple way of getting quota data to disk and we must get
695          * them there for userspace to be visible... */
696         if (sb->s_op->sync_fs)
697                 sb->s_op->sync_fs(sb, 1);
698         sync_blockdev(sb->s_bdev);
699 
700         /*
701          * Now when everything is written we can discard the pagecache so
702          * that userspace sees the changes.
703          */
704         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
705                 if (type != -1 && cnt != type)
706                         continue;
707                 if (!sb_has_quota_active(sb, cnt))
708                         continue;
709                 inode_lock(dqopt->files[cnt]);
710                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
711                 inode_unlock(dqopt->files[cnt]);
712         }
713 
714         return 0;
715 }
716 EXPORT_SYMBOL(dquot_quota_sync);
717 
718 static unsigned long
719 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
720 {
721         struct dquot *dquot;
722         unsigned long freed = 0;
723 
724         spin_lock(&dq_list_lock);
725         while (!list_empty(&free_dquots) && sc->nr_to_scan) {
726                 dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
727                 remove_dquot_hash(dquot);
728                 remove_free_dquot(dquot);
729                 remove_inuse(dquot);
730                 do_destroy_dquot(dquot);
731                 sc->nr_to_scan--;
732                 freed++;
733         }
734         spin_unlock(&dq_list_lock);
735         return freed;
736 }
737 
738 static unsigned long
739 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
740 {
741         return vfs_pressure_ratio(
742         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
743 }
744 
745 static struct shrinker dqcache_shrinker = {
746         .count_objects = dqcache_shrink_count,
747         .scan_objects = dqcache_shrink_scan,
748         .seeks = DEFAULT_SEEKS,
749 };
750 
751 /*
752  * Put reference to dquot
753  */
754 void dqput(struct dquot *dquot)
755 {
756         int ret;
757 
758         if (!dquot)
759                 return;
760 #ifdef CONFIG_QUOTA_DEBUG
761         if (!atomic_read(&dquot->dq_count)) {
762                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
763                             quotatypes[dquot->dq_id.type],
764                             from_kqid(&init_user_ns, dquot->dq_id));
765                 BUG();
766         }
767 #endif
768         dqstats_inc(DQST_DROPS);
769 we_slept:
770         spin_lock(&dq_list_lock);
771         if (atomic_read(&dquot->dq_count) > 1) {
772                 /* We have more than one user... nothing to do */
773                 atomic_dec(&dquot->dq_count);
774                 /* Releasing dquot during quotaoff phase? */
775                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
776                     atomic_read(&dquot->dq_count) == 1)
777                         wake_up(&dquot_ref_wq);
778                 spin_unlock(&dq_list_lock);
779                 return;
780         }
781         /* Need to release dquot? */
782         if (dquot_dirty(dquot)) {
783                 spin_unlock(&dq_list_lock);
784                 /* Commit dquot before releasing */
785                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
786                 if (ret < 0) {
787                         quota_error(dquot->dq_sb, "Can't write quota structure"
788                                     " (error %d). Quota may get out of sync!",
789                                     ret);
790                         /*
791                          * We clear dirty bit anyway, so that we avoid
792                          * infinite loop here
793                          */
794                         clear_dquot_dirty(dquot);
795                 }
796                 goto we_slept;
797         }
798         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
799                 spin_unlock(&dq_list_lock);
800                 dquot->dq_sb->dq_op->release_dquot(dquot);
801                 goto we_slept;
802         }
803         atomic_dec(&dquot->dq_count);
804 #ifdef CONFIG_QUOTA_DEBUG
805         /* sanity check */
806         BUG_ON(!list_empty(&dquot->dq_free));
807 #endif
808         put_dquot_last(dquot);
809         spin_unlock(&dq_list_lock);
810 }
811 EXPORT_SYMBOL(dqput);
812 
813 struct dquot *dquot_alloc(struct super_block *sb, int type)
814 {
815         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
816 }
817 EXPORT_SYMBOL(dquot_alloc);
818 
819 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
820 {
821         struct dquot *dquot;
822 
823         dquot = sb->dq_op->alloc_dquot(sb, type);
824         if(!dquot)
825                 return NULL;
826 
827         mutex_init(&dquot->dq_lock);
828         INIT_LIST_HEAD(&dquot->dq_free);
829         INIT_LIST_HEAD(&dquot->dq_inuse);
830         INIT_HLIST_NODE(&dquot->dq_hash);
831         INIT_LIST_HEAD(&dquot->dq_dirty);
832         dquot->dq_sb = sb;
833         dquot->dq_id = make_kqid_invalid(type);
834         atomic_set(&dquot->dq_count, 1);
835         spin_lock_init(&dquot->dq_dqb_lock);
836 
837         return dquot;
838 }
839 
840 /*
841  * Get reference to dquot
842  *
843  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
844  * destroying our dquot by:
845  *   a) checking for quota flags under dq_list_lock and
846  *   b) getting a reference to dquot before we release dq_list_lock
847  */
848 struct dquot *dqget(struct super_block *sb, struct kqid qid)
849 {
850         unsigned int hashent = hashfn(sb, qid);
851         struct dquot *dquot, *empty = NULL;
852 
853         if (!qid_has_mapping(sb->s_user_ns, qid))
854                 return ERR_PTR(-EINVAL);
855 
856         if (!sb_has_quota_active(sb, qid.type))
857                 return ERR_PTR(-ESRCH);
858 we_slept:
859         spin_lock(&dq_list_lock);
860         spin_lock(&dq_state_lock);
861         if (!sb_has_quota_active(sb, qid.type)) {
862                 spin_unlock(&dq_state_lock);
863                 spin_unlock(&dq_list_lock);
864                 dquot = ERR_PTR(-ESRCH);
865                 goto out;
866         }
867         spin_unlock(&dq_state_lock);
868 
869         dquot = find_dquot(hashent, sb, qid);
870         if (!dquot) {
871                 if (!empty) {
872                         spin_unlock(&dq_list_lock);
873                         empty = get_empty_dquot(sb, qid.type);
874                         if (!empty)
875                                 schedule();     /* Try to wait for a moment... */
876                         goto we_slept;
877                 }
878                 dquot = empty;
879                 empty = NULL;
880                 dquot->dq_id = qid;
881                 /* all dquots go on the inuse_list */
882                 put_inuse(dquot);
883                 /* hash it first so it can be found */
884                 insert_dquot_hash(dquot);
885                 spin_unlock(&dq_list_lock);
886                 dqstats_inc(DQST_LOOKUPS);
887         } else {
888                 if (!atomic_read(&dquot->dq_count))
889                         remove_free_dquot(dquot);
890                 atomic_inc(&dquot->dq_count);
891                 spin_unlock(&dq_list_lock);
892                 dqstats_inc(DQST_CACHE_HITS);
893                 dqstats_inc(DQST_LOOKUPS);
894         }
895         /* Wait for dq_lock - after this we know that either dquot_release() is
896          * already finished or it will be canceled due to dq_count > 1 test */
897         wait_on_dquot(dquot);
898         /* Read the dquot / allocate space in quota file */
899         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
900                 int err;
901 
902                 err = sb->dq_op->acquire_dquot(dquot);
903                 if (err < 0) {
904                         dqput(dquot);
905                         dquot = ERR_PTR(err);
906                         goto out;
907                 }
908         }
909         /*
910          * Make sure following reads see filled structure - paired with
911          * smp_mb__before_atomic() in dquot_acquire().
912          */
913         smp_rmb();
914 #ifdef CONFIG_QUOTA_DEBUG
915         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
916 #endif
917 out:
918         if (empty)
919                 do_destroy_dquot(empty);
920 
921         return dquot;
922 }
923 EXPORT_SYMBOL(dqget);
924 
925 static inline struct dquot **i_dquot(struct inode *inode)
926 {
927         return inode->i_sb->s_op->get_dquots(inode);
928 }
929 
930 static int dqinit_needed(struct inode *inode, int type)
931 {
932         struct dquot * const *dquots;
933         int cnt;
934 
935         if (IS_NOQUOTA(inode))
936                 return 0;
937 
938         dquots = i_dquot(inode);
939         if (type != -1)
940                 return !dquots[type];
941         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
942                 if (!dquots[cnt])
943                         return 1;
944         return 0;
945 }
946 
947 /* This routine is guarded by s_umount semaphore */
948 static int add_dquot_ref(struct super_block *sb, int type)
949 {
950         struct inode *inode, *old_inode = NULL;
951 #ifdef CONFIG_QUOTA_DEBUG
952         int reserved = 0;
953 #endif
954         int err = 0;
955 
956         spin_lock(&sb->s_inode_list_lock);
957         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
958                 spin_lock(&inode->i_lock);
959                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
960                     !atomic_read(&inode->i_writecount) ||
961                     !dqinit_needed(inode, type)) {
962                         spin_unlock(&inode->i_lock);
963                         continue;
964                 }
965                 __iget(inode);
966                 spin_unlock(&inode->i_lock);
967                 spin_unlock(&sb->s_inode_list_lock);
968 
969 #ifdef CONFIG_QUOTA_DEBUG
970                 if (unlikely(inode_get_rsv_space(inode) > 0))
971                         reserved = 1;
972 #endif
973                 iput(old_inode);
974                 err = __dquot_initialize(inode, type);
975                 if (err) {
976                         iput(inode);
977                         goto out;
978                 }
979 
980                 /*
981                  * We hold a reference to 'inode' so it couldn't have been
982                  * removed from s_inodes list while we dropped the
983                  * s_inode_list_lock. We cannot iput the inode now as we can be
984                  * holding the last reference and we cannot iput it under
985                  * s_inode_list_lock. So we keep the reference and iput it
986                  * later.
987                  */
988                 old_inode = inode;
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 /*
2167  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2168  */
2169 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2170 {
2171         int cnt, ret = 0;
2172         struct quota_info *dqopt = sb_dqopt(sb);
2173         struct inode *toputinode[MAXQUOTAS];
2174 
2175         /* s_umount should be held in exclusive mode */
2176         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2177                 up_read(&sb->s_umount);
2178 
2179         /* Cannot turn off usage accounting without turning off limits, or
2180          * suspend quotas and simultaneously turn quotas off. */
2181         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2182             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2183             DQUOT_USAGE_ENABLED)))
2184                 return -EINVAL;
2185 
2186         /*
2187          * Skip everything if there's nothing to do. We have to do this because
2188          * sometimes we are called when fill_super() failed and calling
2189          * sync_fs() in such cases does no good.
2190          */
2191         if (!sb_any_quota_loaded(sb))
2192                 return 0;
2193 
2194         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2195                 toputinode[cnt] = NULL;
2196                 if (type != -1 && cnt != type)
2197                         continue;
2198                 if (!sb_has_quota_loaded(sb, cnt))
2199                         continue;
2200 
2201                 if (flags & DQUOT_SUSPENDED) {
2202                         spin_lock(&dq_state_lock);
2203                         dqopt->flags |=
2204                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2205                         spin_unlock(&dq_state_lock);
2206                 } else {
2207                         spin_lock(&dq_state_lock);
2208                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2209                         /* Turning off suspended quotas? */
2210                         if (!sb_has_quota_loaded(sb, cnt) &&
2211                             sb_has_quota_suspended(sb, cnt)) {
2212                                 dqopt->flags &= ~dquot_state_flag(
2213                                                         DQUOT_SUSPENDED, cnt);
2214                                 spin_unlock(&dq_state_lock);
2215                                 iput(dqopt->files[cnt]);
2216                                 dqopt->files[cnt] = NULL;
2217                                 continue;
2218                         }
2219                         spin_unlock(&dq_state_lock);
2220                 }
2221 
2222                 /* We still have to keep quota loaded? */
2223                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2224                         continue;
2225 
2226                 /* Note: these are blocking operations */
2227                 drop_dquot_ref(sb, cnt);
2228                 invalidate_dquots(sb, cnt);
2229                 /*
2230                  * Now all dquots should be invalidated, all writes done so we
2231                  * should be only users of the info. No locks needed.
2232                  */
2233                 if (info_dirty(&dqopt->info[cnt]))
2234                         sb->dq_op->write_info(sb, cnt);
2235                 if (dqopt->ops[cnt]->free_file_info)
2236                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2237                 put_quota_format(dqopt->info[cnt].dqi_format);
2238 
2239                 toputinode[cnt] = dqopt->files[cnt];
2240                 if (!sb_has_quota_loaded(sb, cnt))
2241                         dqopt->files[cnt] = NULL;
2242                 dqopt->info[cnt].dqi_flags = 0;
2243                 dqopt->info[cnt].dqi_igrace = 0;
2244                 dqopt->info[cnt].dqi_bgrace = 0;
2245                 dqopt->ops[cnt] = NULL;
2246         }
2247 
2248         /* Skip syncing and setting flags if quota files are hidden */
2249         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2250                 goto put_inodes;
2251 
2252         /* Sync the superblock so that buffers with quota data are written to
2253          * disk (and so userspace sees correct data afterwards). */
2254         if (sb->s_op->sync_fs)
2255                 sb->s_op->sync_fs(sb, 1);
2256         sync_blockdev(sb->s_bdev);
2257         /* Now the quota files are just ordinary files and we can set the
2258          * inode flags back. Moreover we discard the pagecache so that
2259          * userspace sees the writes we did bypassing the pagecache. We
2260          * must also discard the blockdev buffers so that we see the
2261          * changes done by userspace on the next quotaon() */
2262         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2263                 /* This can happen when suspending quotas on remount-ro... */
2264                 if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {
2265                         inode_lock(toputinode[cnt]);
2266                         toputinode[cnt]->i_flags &= ~S_NOQUOTA;
2267                         truncate_inode_pages(&toputinode[cnt]->i_data, 0);
2268                         inode_unlock(toputinode[cnt]);
2269                         mark_inode_dirty_sync(toputinode[cnt]);
2270                 }
2271         if (sb->s_bdev)
2272                 invalidate_bdev(sb->s_bdev);
2273 put_inodes:
2274         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2275                 if (toputinode[cnt]) {
2276                         /* On remount RO, we keep the inode pointer so that we
2277                          * can reenable quota on the subsequent remount RW. We
2278                          * have to check 'flags' variable and not use sb_has_
2279                          * function because another quotaon / quotaoff could
2280                          * change global state before we got here. We refuse
2281                          * to suspend quotas when there is pending delete on
2282                          * the quota file... */
2283                         if (!(flags & DQUOT_SUSPENDED))
2284                                 iput(toputinode[cnt]);
2285                         else if (!toputinode[cnt]->i_nlink)
2286                                 ret = -EBUSY;
2287                 }
2288         return ret;
2289 }
2290 EXPORT_SYMBOL(dquot_disable);
2291 
2292 int dquot_quota_off(struct super_block *sb, int type)
2293 {
2294         return dquot_disable(sb, type,
2295                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2296 }
2297 EXPORT_SYMBOL(dquot_quota_off);
2298 
2299 /*
2300  *      Turn quotas on on a device
2301  */
2302 
2303 /*
2304  * Helper function to turn quotas on when we already have the inode of
2305  * quota file and no quota information is loaded.
2306  */
2307 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
2308         unsigned int flags)
2309 {
2310         struct quota_format_type *fmt = find_quota_format(format_id);
2311         struct super_block *sb = inode->i_sb;
2312         struct quota_info *dqopt = sb_dqopt(sb);
2313         int error;
2314 
2315         if (!fmt)
2316                 return -ESRCH;
2317         if (!S_ISREG(inode->i_mode)) {
2318                 error = -EACCES;
2319                 goto out_fmt;
2320         }
2321         if (IS_RDONLY(inode)) {
2322                 error = -EROFS;
2323                 goto out_fmt;
2324         }
2325         if (!sb->s_op->quota_write || !sb->s_op->quota_read ||
2326             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2327                 error = -EINVAL;
2328                 goto out_fmt;
2329         }
2330         /* Filesystems outside of init_user_ns not yet supported */
2331         if (sb->s_user_ns != &init_user_ns) {
2332                 error = -EINVAL;
2333                 goto out_fmt;
2334         }
2335         /* Usage always has to be set... */
2336         if (!(flags & DQUOT_USAGE_ENABLED)) {
2337                 error = -EINVAL;
2338                 goto out_fmt;
2339         }
2340         if (sb_has_quota_loaded(sb, type)) {
2341                 error = -EBUSY;
2342                 goto out_fmt;
2343         }
2344 
2345         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2346                 /* As we bypass the pagecache we must now flush all the
2347                  * dirty data and invalidate caches so that kernel sees
2348                  * changes from userspace. It is not enough to just flush
2349                  * the quota file since if blocksize < pagesize, invalidation
2350                  * of the cache could fail because of other unrelated dirty
2351                  * data */
2352                 sync_filesystem(sb);
2353                 invalidate_bdev(sb->s_bdev);
2354         }
2355 
2356         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2357                 /* We don't want quota and atime on quota files (deadlocks
2358                  * possible) Also nobody should write to the file - we use
2359                  * special IO operations which ignore the immutable bit. */
2360                 inode_lock(inode);
2361                 inode->i_flags |= S_NOQUOTA;
2362                 inode_unlock(inode);
2363                 /*
2364                  * When S_NOQUOTA is set, remove dquot references as no more
2365                  * references can be added
2366                  */
2367                 __dquot_drop(inode);
2368         }
2369 
2370         error = -EIO;
2371         dqopt->files[type] = igrab(inode);
2372         if (!dqopt->files[type])
2373                 goto out_file_flags;
2374         error = -EINVAL;
2375         if (!fmt->qf_ops->check_quota_file(sb, type))
2376                 goto out_file_init;
2377 
2378         dqopt->ops[type] = fmt->qf_ops;
2379         dqopt->info[type].dqi_format = fmt;
2380         dqopt->info[type].dqi_fmt_id = format_id;
2381         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2382         error = dqopt->ops[type]->read_file_info(sb, type);
2383         if (error < 0)
2384                 goto out_file_init;
2385         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2386                 spin_lock(&dq_data_lock);
2387                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2388                 spin_unlock(&dq_data_lock);
2389         }
2390         spin_lock(&dq_state_lock);
2391         dqopt->flags |= dquot_state_flag(flags, type);
2392         spin_unlock(&dq_state_lock);
2393 
2394         error = add_dquot_ref(sb, type);
2395         if (error)
2396                 dquot_disable(sb, type, flags);
2397 
2398         return error;
2399 out_file_init:
2400         dqopt->files[type] = NULL;
2401         iput(inode);
2402 out_file_flags:
2403         inode_lock(inode);
2404         inode->i_flags &= ~S_NOQUOTA;
2405         inode_unlock(inode);
2406 out_fmt:
2407         put_quota_format(fmt);
2408 
2409         return error;
2410 }
2411 
2412 /* Reenable quotas on remount RW */
2413 int dquot_resume(struct super_block *sb, int type)
2414 {
2415         struct quota_info *dqopt = sb_dqopt(sb);
2416         struct inode *inode;
2417         int ret = 0, cnt;
2418         unsigned int flags;
2419 
2420         /* s_umount should be held in exclusive mode */
2421         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2422                 up_read(&sb->s_umount);
2423 
2424         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2425                 if (type != -1 && cnt != type)
2426                         continue;
2427                 if (!sb_has_quota_suspended(sb, cnt))
2428                         continue;
2429 
2430                 inode = dqopt->files[cnt];
2431                 dqopt->files[cnt] = NULL;
2432                 spin_lock(&dq_state_lock);
2433                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2434                                                         DQUOT_LIMITS_ENABLED,
2435                                                         cnt);
2436                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2437                 spin_unlock(&dq_state_lock);
2438 
2439                 flags = dquot_generic_flag(flags, cnt);
2440                 ret = vfs_load_quota_inode(inode, cnt,
2441                                 dqopt->info[cnt].dqi_fmt_id, flags);
2442                 iput(inode);
2443         }
2444 
2445         return ret;
2446 }
2447 EXPORT_SYMBOL(dquot_resume);
2448 
2449 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2450                    const struct path *path)
2451 {
2452         int error = security_quota_on(path->dentry);
2453         if (error)
2454                 return error;
2455         /* Quota file not on the same filesystem? */
2456         if (path->dentry->d_sb != sb)
2457                 error = -EXDEV;
2458         else
2459                 error = vfs_load_quota_inode(d_inode(path->dentry), type,
2460                                              format_id, DQUOT_USAGE_ENABLED |
2461                                              DQUOT_LIMITS_ENABLED);
2462         return error;
2463 }
2464 EXPORT_SYMBOL(dquot_quota_on);
2465 
2466 /*
2467  * More powerful function for turning on quotas allowing setting
2468  * of individual quota flags
2469  */
2470 int dquot_enable(struct inode *inode, int type, int format_id,
2471                  unsigned int flags)
2472 {
2473         struct super_block *sb = inode->i_sb;
2474 
2475         /* Just unsuspend quotas? */
2476         BUG_ON(flags & DQUOT_SUSPENDED);
2477         /* s_umount should be held in exclusive mode */
2478         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2479                 up_read(&sb->s_umount);
2480 
2481         if (!flags)
2482                 return 0;
2483         /* Just updating flags needed? */
2484         if (sb_has_quota_loaded(sb, type)) {
2485                 if (flags & DQUOT_USAGE_ENABLED &&
2486                     sb_has_quota_usage_enabled(sb, type))
2487                         return -EBUSY;
2488                 if (flags & DQUOT_LIMITS_ENABLED &&
2489                     sb_has_quota_limits_enabled(sb, type))
2490                         return -EBUSY;
2491                 spin_lock(&dq_state_lock);
2492                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2493                 spin_unlock(&dq_state_lock);
2494                 return 0;
2495         }
2496 
2497         return vfs_load_quota_inode(inode, type, format_id, flags);
2498 }
2499 EXPORT_SYMBOL(dquot_enable);
2500 
2501 /*
2502  * This function is used when filesystem needs to initialize quotas
2503  * during mount time.
2504  */
2505 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2506                 int format_id, int type)
2507 {
2508         struct dentry *dentry;
2509         int error;
2510 
2511         dentry = lookup_one_len_unlocked(qf_name, sb->s_root, strlen(qf_name));
2512         if (IS_ERR(dentry))
2513                 return PTR_ERR(dentry);
2514 
2515         if (d_really_is_negative(dentry)) {
2516                 error = -ENOENT;
2517                 goto out;
2518         }
2519 
2520         error = security_quota_on(dentry);
2521         if (!error)
2522                 error = vfs_load_quota_inode(d_inode(dentry), type, format_id,
2523                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2524 
2525 out:
2526         dput(dentry);
2527         return error;
2528 }
2529 EXPORT_SYMBOL(dquot_quota_on_mount);
2530 
2531 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2532 {
2533         int ret;
2534         int type;
2535         struct quota_info *dqopt = sb_dqopt(sb);
2536 
2537         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2538                 return -ENOSYS;
2539         /* Accounting cannot be turned on while fs is mounted */
2540         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2541         if (!flags)
2542                 return -EINVAL;
2543         for (type = 0; type < MAXQUOTAS; type++) {
2544                 if (!(flags & qtype_enforce_flag(type)))
2545                         continue;
2546                 /* Can't enforce without accounting */
2547                 if (!sb_has_quota_usage_enabled(sb, type))
2548                         return -EINVAL;
2549                 ret = dquot_enable(dqopt->files[type], type,
2550                                    dqopt->info[type].dqi_fmt_id,
2551                                    DQUOT_LIMITS_ENABLED);
2552                 if (ret < 0)
2553                         goto out_err;
2554         }
2555         return 0;
2556 out_err:
2557         /* Backout enforcement enablement we already did */
2558         for (type--; type >= 0; type--)  {
2559                 if (flags & qtype_enforce_flag(type))
2560                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2561         }
2562         /* Error code translation for better compatibility with XFS */
2563         if (ret == -EBUSY)
2564                 ret = -EEXIST;
2565         return ret;
2566 }
2567 
2568 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2569 {
2570         int ret;
2571         int type;
2572         struct quota_info *dqopt = sb_dqopt(sb);
2573 
2574         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2575                 return -ENOSYS;
2576         /*
2577          * We don't support turning off accounting via quotactl. In principle
2578          * quota infrastructure can do this but filesystems don't expect
2579          * userspace to be able to do it.
2580          */
2581         if (flags &
2582                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2583                 return -EOPNOTSUPP;
2584 
2585         /* Filter out limits not enabled */
2586         for (type = 0; type < MAXQUOTAS; type++)
2587                 if (!sb_has_quota_limits_enabled(sb, type))
2588                         flags &= ~qtype_enforce_flag(type);
2589         /* Nothing left? */
2590         if (!flags)
2591                 return -EEXIST;
2592         for (type = 0; type < MAXQUOTAS; type++) {
2593                 if (flags & qtype_enforce_flag(type)) {
2594                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2595                         if (ret < 0)
2596                                 goto out_err;
2597                 }
2598         }
2599         return 0;
2600 out_err:
2601         /* Backout enforcement disabling we already did */
2602         for (type--; type >= 0; type--)  {
2603                 if (flags & qtype_enforce_flag(type))
2604                         dquot_enable(dqopt->files[type], type,
2605                                      dqopt->info[type].dqi_fmt_id,
2606                                      DQUOT_LIMITS_ENABLED);
2607         }
2608         return ret;
2609 }
2610 
2611 /* Generic routine for getting common part of quota structure */
2612 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2613 {
2614         struct mem_dqblk *dm = &dquot->dq_dqb;
2615 
2616         memset(di, 0, sizeof(*di));
2617         spin_lock(&dquot->dq_dqb_lock);
2618         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2619         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2620         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2621         di->d_ino_softlimit = dm->dqb_isoftlimit;
2622         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2623         di->d_ino_count = dm->dqb_curinodes;
2624         di->d_spc_timer = dm->dqb_btime;
2625         di->d_ino_timer = dm->dqb_itime;
2626         spin_unlock(&dquot->dq_dqb_lock);
2627 }
2628 
2629 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2630                     struct qc_dqblk *di)
2631 {
2632         struct dquot *dquot;
2633 
2634         dquot = dqget(sb, qid);
2635         if (IS_ERR(dquot))
2636                 return PTR_ERR(dquot);
2637         do_get_dqblk(dquot, di);
2638         dqput(dquot);
2639 
2640         return 0;
2641 }
2642 EXPORT_SYMBOL(dquot_get_dqblk);
2643 
2644 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2645                          struct qc_dqblk *di)
2646 {
2647         struct dquot *dquot;
2648         int err;
2649 
2650         if (!sb->dq_op->get_next_id)
2651                 return -ENOSYS;
2652         err = sb->dq_op->get_next_id(sb, qid);
2653         if (err < 0)
2654                 return err;
2655         dquot = dqget(sb, *qid);
2656         if (IS_ERR(dquot))
2657                 return PTR_ERR(dquot);
2658         do_get_dqblk(dquot, di);
2659         dqput(dquot);
2660 
2661         return 0;
2662 }
2663 EXPORT_SYMBOL(dquot_get_next_dqblk);
2664 
2665 #define VFS_QC_MASK \
2666         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2667          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2668          QC_SPC_TIMER | QC_INO_TIMER)
2669 
2670 /* Generic routine for setting common part of quota structure */
2671 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2672 {
2673         struct mem_dqblk *dm = &dquot->dq_dqb;
2674         int check_blim = 0, check_ilim = 0;
2675         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2676 
2677         if (di->d_fieldmask & ~VFS_QC_MASK)
2678                 return -EINVAL;
2679 
2680         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2681              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2682             ((di->d_fieldmask & QC_SPC_HARD) &&
2683              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2684             ((di->d_fieldmask & QC_INO_SOFT) &&
2685              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2686             ((di->d_fieldmask & QC_INO_HARD) &&
2687              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2688                 return -ERANGE;
2689 
2690         spin_lock(&dquot->dq_dqb_lock);
2691         if (di->d_fieldmask & QC_SPACE) {
2692                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2693                 check_blim = 1;
2694                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2695         }
2696 
2697         if (di->d_fieldmask & QC_SPC_SOFT)
2698                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2699         if (di->d_fieldmask & QC_SPC_HARD)
2700                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2701         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2702                 check_blim = 1;
2703                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2704         }
2705 
2706         if (di->d_fieldmask & QC_INO_COUNT) {
2707                 dm->dqb_curinodes = di->d_ino_count;
2708                 check_ilim = 1;
2709                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2710         }
2711 
2712         if (di->d_fieldmask & QC_INO_SOFT)
2713                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2714         if (di->d_fieldmask & QC_INO_HARD)
2715                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2716         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2717                 check_ilim = 1;
2718                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2719         }
2720 
2721         if (di->d_fieldmask & QC_SPC_TIMER) {
2722                 dm->dqb_btime = di->d_spc_timer;
2723                 check_blim = 1;
2724                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2725         }
2726 
2727         if (di->d_fieldmask & QC_INO_TIMER) {
2728                 dm->dqb_itime = di->d_ino_timer;
2729                 check_ilim = 1;
2730                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2731         }
2732 
2733         if (check_blim) {
2734                 if (!dm->dqb_bsoftlimit ||
2735                     dm->dqb_curspace + dm->dqb_rsvspace < dm->dqb_bsoftlimit) {
2736                         dm->dqb_btime = 0;
2737                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2738                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2739                         /* Set grace only if user hasn't provided his own... */
2740                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2741         }
2742         if (check_ilim) {
2743                 if (!dm->dqb_isoftlimit ||
2744                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2745                         dm->dqb_itime = 0;
2746                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2747                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2748                         /* Set grace only if user hasn't provided his own... */
2749                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2750         }
2751         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2752             dm->dqb_isoftlimit)
2753                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2754         else
2755                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2756         spin_unlock(&dquot->dq_dqb_lock);
2757         mark_dquot_dirty(dquot);
2758 
2759         return 0;
2760 }
2761 
2762 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2763                   struct qc_dqblk *di)
2764 {
2765         struct dquot *dquot;
2766         int rc;
2767 
2768         dquot = dqget(sb, qid);
2769         if (IS_ERR(dquot)) {
2770                 rc = PTR_ERR(dquot);
2771                 goto out;
2772         }
2773         rc = do_set_dqblk(dquot, di);
2774         dqput(dquot);
2775 out:
2776         return rc;
2777 }
2778 EXPORT_SYMBOL(dquot_set_dqblk);
2779 
2780 /* Generic routine for getting common part of quota file information */
2781 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2782 {
2783         struct mem_dqinfo *mi;
2784         struct qc_type_state *tstate;
2785         struct quota_info *dqopt = sb_dqopt(sb);
2786         int type;
2787 
2788         memset(state, 0, sizeof(*state));
2789         for (type = 0; type < MAXQUOTAS; type++) {
2790                 if (!sb_has_quota_active(sb, type))
2791                         continue;
2792                 tstate = state->s_state + type;
2793                 mi = sb_dqopt(sb)->info + type;
2794                 tstate->flags = QCI_ACCT_ENABLED;
2795                 spin_lock(&dq_data_lock);
2796                 if (mi->dqi_flags & DQF_SYS_FILE)
2797                         tstate->flags |= QCI_SYSFILE;
2798                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2799                         tstate->flags |= QCI_ROOT_SQUASH;
2800                 if (sb_has_quota_limits_enabled(sb, type))
2801                         tstate->flags |= QCI_LIMITS_ENFORCED;
2802                 tstate->spc_timelimit = mi->dqi_bgrace;
2803                 tstate->ino_timelimit = mi->dqi_igrace;
2804                 tstate->ino = dqopt->files[type]->i_ino;
2805                 tstate->blocks = dqopt->files[type]->i_blocks;
2806                 tstate->nextents = 1;   /* We don't know... */
2807                 spin_unlock(&dq_data_lock);
2808         }
2809         return 0;
2810 }
2811 EXPORT_SYMBOL(dquot_get_state);
2812 
2813 /* Generic routine for setting common part of quota file information */
2814 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2815 {
2816         struct mem_dqinfo *mi;
2817         int err = 0;
2818 
2819         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2820             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2821                 return -EINVAL;
2822         if (!sb_has_quota_active(sb, type))
2823                 return -ESRCH;
2824         mi = sb_dqopt(sb)->info + type;
2825         if (ii->i_fieldmask & QC_FLAGS) {
2826                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2827                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2828                         return -EINVAL;
2829         }
2830         spin_lock(&dq_data_lock);
2831         if (ii->i_fieldmask & QC_SPC_TIMER)
2832                 mi->dqi_bgrace = ii->i_spc_timelimit;
2833         if (ii->i_fieldmask & QC_INO_TIMER)
2834                 mi->dqi_igrace = ii->i_ino_timelimit;
2835         if (ii->i_fieldmask & QC_FLAGS) {
2836                 if (ii->i_flags & QCI_ROOT_SQUASH)
2837                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2838                 else
2839                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2840         }
2841         spin_unlock(&dq_data_lock);
2842         mark_info_dirty(sb, type);
2843         /* Force write to disk */
2844         sb->dq_op->write_info(sb, type);
2845         return err;
2846 }
2847 EXPORT_SYMBOL(dquot_set_dqinfo);
2848 
2849 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2850         .quota_enable   = dquot_quota_enable,
2851         .quota_disable  = dquot_quota_disable,
2852         .quota_sync     = dquot_quota_sync,
2853         .get_state      = dquot_get_state,
2854         .set_info       = dquot_set_dqinfo,
2855         .get_dqblk      = dquot_get_dqblk,
2856         .get_nextdqblk  = dquot_get_next_dqblk,
2857         .set_dqblk      = dquot_set_dqblk
2858 };
2859 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2860 
2861 static int do_proc_dqstats(struct ctl_table *table, int write,
2862                      void __user *buffer, size_t *lenp, loff_t *ppos)
2863 {
2864         unsigned int type = (int *)table->data - dqstats.stat;
2865 
2866         /* Update global table */
2867         dqstats.stat[type] =
2868                         percpu_counter_sum_positive(&dqstats.counter[type]);
2869         return proc_dointvec(table, write, buffer, lenp, ppos);
2870 }
2871 
2872 static struct ctl_table fs_dqstats_table[] = {
2873         {
2874                 .procname       = "lookups",
2875                 .data           = &dqstats.stat[DQST_LOOKUPS],
2876                 .maxlen         = sizeof(int),
2877                 .mode           = 0444,
2878                 .proc_handler   = do_proc_dqstats,
2879         },
2880         {
2881                 .procname       = "drops",
2882                 .data           = &dqstats.stat[DQST_DROPS],
2883                 .maxlen         = sizeof(int),
2884                 .mode           = 0444,
2885                 .proc_handler   = do_proc_dqstats,
2886         },
2887         {
2888                 .procname       = "reads",
2889                 .data           = &dqstats.stat[DQST_READS],
2890                 .maxlen         = sizeof(int),
2891                 .mode           = 0444,
2892                 .proc_handler   = do_proc_dqstats,
2893         },
2894         {
2895                 .procname       = "writes",
2896                 .data           = &dqstats.stat[DQST_WRITES],
2897                 .maxlen         = sizeof(int),
2898                 .mode           = 0444,
2899                 .proc_handler   = do_proc_dqstats,
2900         },
2901         {
2902                 .procname       = "cache_hits",
2903                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2904                 .maxlen         = sizeof(int),
2905                 .mode           = 0444,
2906                 .proc_handler   = do_proc_dqstats,
2907         },
2908         {
2909                 .procname       = "allocated_dquots",
2910                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2911                 .maxlen         = sizeof(int),
2912                 .mode           = 0444,
2913                 .proc_handler   = do_proc_dqstats,
2914         },
2915         {
2916                 .procname       = "free_dquots",
2917                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2918                 .maxlen         = sizeof(int),
2919                 .mode           = 0444,
2920                 .proc_handler   = do_proc_dqstats,
2921         },
2922         {
2923                 .procname       = "syncs",
2924                 .data           = &dqstats.stat[DQST_SYNCS],
2925                 .maxlen         = sizeof(int),
2926                 .mode           = 0444,
2927                 .proc_handler   = do_proc_dqstats,
2928         },
2929 #ifdef CONFIG_PRINT_QUOTA_WARNING
2930         {
2931                 .procname       = "warnings",
2932                 .data           = &flag_print_warnings,
2933                 .maxlen         = sizeof(int),
2934                 .mode           = 0644,
2935                 .proc_handler   = proc_dointvec,
2936         },
2937 #endif
2938         { },
2939 };
2940 
2941 static struct ctl_table fs_table[] = {
2942         {
2943                 .procname       = "quota",
2944                 .mode           = 0555,
2945                 .child          = fs_dqstats_table,
2946         },
2947         { },
2948 };
2949 
2950 static struct ctl_table sys_table[] = {
2951         {
2952                 .procname       = "fs",
2953                 .mode           = 0555,
2954                 .child          = fs_table,
2955         },
2956         { },
2957 };
2958 
2959 static int __init dquot_init(void)
2960 {
2961         int i, ret;
2962         unsigned long nr_hash, order;
2963 
2964         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2965 
2966         register_sysctl_table(sys_table);
2967 
2968         dquot_cachep = kmem_cache_create("dquot",
2969                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2970                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2971                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2972                         NULL);
2973 
2974         order = 0;
2975         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_KERNEL, order);
2976         if (!dquot_hash)
2977                 panic("Cannot create dquot hash table");
2978 
2979         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2980                 ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
2981                 if (ret)
2982                         panic("Cannot create dquot stat counters");
2983         }
2984 
2985         /* Find power-of-two hlist_heads which can fit into allocation */
2986         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2987         dq_hash_bits = 0;
2988         do {
2989                 dq_hash_bits++;
2990         } while (nr_hash >> dq_hash_bits);
2991         dq_hash_bits--;
2992 
2993         nr_hash = 1UL << dq_hash_bits;
2994         dq_hash_mask = nr_hash - 1;
2995         for (i = 0; i < nr_hash; i++)
2996                 INIT_HLIST_HEAD(dquot_hash + i);
2997 
2998         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
2999                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
3000 
3001         if (register_shrinker(&dqcache_shrinker))
3002                 panic("Cannot register dquot shrinker");
3003 
3004         return 0;
3005 }
3006 fs_initcall(dquot_init);
3007 

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