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

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  1 /*
  2  * Implementation of the diskquota system for the LINUX operating system. QUOTA
  3  * is implemented using the BSD system call interface as the means of
  4  * communication with the user level. This file contains the generic routines
  5  * called by the different filesystems on allocation of an inode or block.
  6  * These routines take care of the administration needed to have a consistent
  7  * diskquota tracking system. The ideas of both user and group quotas are based
  8  * on the Melbourne quota system as used on BSD derived systems. The internal
  9  * implementation is based on one of the several variants of the LINUX
 10  * inode-subsystem with added complexity of the diskquota system.
 11  * 
 12  * Author:      Marco van Wieringen <mvw@planets.elm.net>
 13  *
 14  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
 15  *
 16  *              Revised list management to avoid races
 17  *              -- Bill Hawes, <whawes@star.net>, 9/98
 18  *
 19  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
 20  *              As the consequence the locking was moved from dquot_decr_...(),
 21  *              dquot_incr_...() to calling functions.
 22  *              invalidate_dquots() now writes modified dquots.
 23  *              Serialized quota_off() and quota_on() for mount point.
 24  *              Fixed a few bugs in grow_dquots().
 25  *              Fixed deadlock in write_dquot() - we no longer account quotas on
 26  *              quota files
 27  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
 28  *              add_dquot_ref() restarts after blocking
 29  *              Added check for bogus uid and fixed check for group in quotactl.
 30  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
 31  *
 32  *              Used struct list_head instead of own list struct
 33  *              Invalidation of referenced dquots is no longer possible
 34  *              Improved free_dquots list management
 35  *              Quota and i_blocks are now updated in one place to avoid races
 36  *              Warnings are now delayed so we won't block in critical section
 37  *              Write updated not to require dquot lock
 38  *              Jan Kara, <jack@suse.cz>, 9/2000
 39  *
 40  *              Added dynamic quota structure allocation
 41  *              Jan Kara <jack@suse.cz> 12/2000
 42  *
 43  *              Rewritten quota interface. Implemented new quota format and
 44  *              formats registering.
 45  *              Jan Kara, <jack@suse.cz>, 2001,2002
 46  *
 47  *              New SMP locking.
 48  *              Jan Kara, <jack@suse.cz>, 10/2002
 49  *
 50  *              Added journalled quota support, fix lock inversion problems
 51  *              Jan Kara, <jack@suse.cz>, 2003,2004
 52  *
 53  * (C) Copyright 1994 - 1997 Marco van Wieringen 
 54  */
 55 
 56 #include <linux/errno.h>
 57 #include <linux/kernel.h>
 58 #include <linux/fs.h>
 59 #include <linux/mount.h>
 60 #include <linux/mm.h>
 61 #include <linux/time.h>
 62 #include <linux/types.h>
 63 #include <linux/string.h>
 64 #include <linux/fcntl.h>
 65 #include <linux/stat.h>
 66 #include <linux/tty.h>
 67 #include <linux/file.h>
 68 #include <linux/slab.h>
 69 #include <linux/sysctl.h>
 70 #include <linux/init.h>
 71 #include <linux/module.h>
 72 #include <linux/proc_fs.h>
 73 #include <linux/security.h>
 74 #include <linux/sched.h>
 75 #include <linux/kmod.h>
 76 #include <linux/namei.h>
 77 #include <linux/capability.h>
 78 #include <linux/quotaops.h>
 79 #include "../internal.h" /* ugh */
 80 
 81 #include <linux/uaccess.h>
 82 
 83 /*
 84  * There are three quota SMP locks. dq_list_lock protects all lists with quotas
 85  * and quota formats.
 86  * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
 87  * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
 88  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
 89  * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
 90  * modifications of quota state (on quotaon and quotaoff) and readers who care
 91  * about latest values take it as well.
 92  *
 93  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
 94  *   dq_list_lock > dq_state_lock
 95  *
 96  * Note that some things (eg. sb pointer, type, id) doesn't change during
 97  * the life of the dquot structure and so needn't to be protected by a lock
 98  *
 99  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
100  * operation is just reading pointers from inode (or not using them at all) the
101  * read lock is enough. If pointers are altered function must hold write lock.
102  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
103  * inode is a quota file). Functions adding pointers from inode to dquots have
104  * to check this flag under dqptr_sem and then (if S_NOQUOTA is not set) they
105  * have to do all pointer modifications before dropping dqptr_sem. This makes
106  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
107  * then drops all pointers to dquots from an inode.
108  *
109  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
110  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
111  * Currently dquot is locked only when it is being read to memory (or space for
112  * it is being allocated) on the first dqget() and when it is being released on
113  * the last dqput(). The allocation and release oparations are serialized by
114  * the dq_lock and by checking the use count in dquot_release().  Write
115  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
116  * spinlock to internal buffers before writing.
117  *
118  * Lock ordering (including related VFS locks) is the following:
119  *   dqonoff_mutex > i_mutex > journal_lock > dqptr_sem > dquot->dq_lock >
120  *   dqio_mutex
121  * dqonoff_mutex > i_mutex comes from dquot_quota_sync, dquot_enable, etc.
122  * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
123  * dqptr_sem. But filesystem has to count with the fact that functions such as
124  * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
125  * from inside a transaction to keep filesystem consistency after a crash. Also
126  * filesystems usually want to do some IO on dquot from ->mark_dirty which is
127  * called with dqptr_sem held.
128  */
129 
130 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
131 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
132 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
133 EXPORT_SYMBOL(dq_data_lock);
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 three lists for dquot management: the inuse_list,
227  * free_dquots, and dquot_hash[] array. A single dquot structure may be
228  * on all three 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  * Dquots with a specific identity (device, type and id) are placed on
240  * one of the dquot_hash[] hash chains. The provides an efficient search
241  * mechanism to locate a specific dquot.
242  */
243 
244 static LIST_HEAD(inuse_list);
245 static LIST_HEAD(free_dquots);
246 static unsigned int dq_hash_bits, dq_hash_mask;
247 static struct hlist_head *dquot_hash;
248 
249 struct dqstats dqstats;
250 EXPORT_SYMBOL(dqstats);
251 
252 static qsize_t inode_get_rsv_space(struct inode *inode);
253 static void __dquot_initialize(struct inode *inode, int type);
254 
255 static inline unsigned int
256 hashfn(const struct super_block *sb, struct kqid qid)
257 {
258         unsigned int id = from_kqid(&init_user_ns, qid);
259         int type = qid.type;
260         unsigned long tmp;
261 
262         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
263         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
264 }
265 
266 /*
267  * Following list functions expect dq_list_lock to be held
268  */
269 static inline void insert_dquot_hash(struct dquot *dquot)
270 {
271         struct hlist_head *head;
272         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
273         hlist_add_head(&dquot->dq_hash, head);
274 }
275 
276 static inline void remove_dquot_hash(struct dquot *dquot)
277 {
278         hlist_del_init(&dquot->dq_hash);
279 }
280 
281 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
282                                 struct kqid qid)
283 {
284         struct hlist_node *node;
285         struct dquot *dquot;
286 
287         hlist_for_each (node, dquot_hash+hashent) {
288                 dquot = hlist_entry(node, struct dquot, dq_hash);
289                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
290                         return dquot;
291         }
292         return NULL;
293 }
294 
295 /* Add a dquot to the tail of the free list */
296 static inline void put_dquot_last(struct dquot *dquot)
297 {
298         list_add_tail(&dquot->dq_free, &free_dquots);
299         dqstats_inc(DQST_FREE_DQUOTS);
300 }
301 
302 static inline void remove_free_dquot(struct dquot *dquot)
303 {
304         if (list_empty(&dquot->dq_free))
305                 return;
306         list_del_init(&dquot->dq_free);
307         dqstats_dec(DQST_FREE_DQUOTS);
308 }
309 
310 static inline void put_inuse(struct dquot *dquot)
311 {
312         /* We add to the back of inuse list so we don't have to restart
313          * when traversing this list and we block */
314         list_add_tail(&dquot->dq_inuse, &inuse_list);
315         dqstats_inc(DQST_ALLOC_DQUOTS);
316 }
317 
318 static inline void remove_inuse(struct dquot *dquot)
319 {
320         dqstats_dec(DQST_ALLOC_DQUOTS);
321         list_del(&dquot->dq_inuse);
322 }
323 /*
324  * End of list functions needing dq_list_lock
325  */
326 
327 static void wait_on_dquot(struct dquot *dquot)
328 {
329         mutex_lock(&dquot->dq_lock);
330         mutex_unlock(&dquot->dq_lock);
331 }
332 
333 static inline int dquot_dirty(struct dquot *dquot)
334 {
335         return test_bit(DQ_MOD_B, &dquot->dq_flags);
336 }
337 
338 static inline int mark_dquot_dirty(struct dquot *dquot)
339 {
340         return dquot->dq_sb->dq_op->mark_dirty(dquot);
341 }
342 
343 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
344 int dquot_mark_dquot_dirty(struct dquot *dquot)
345 {
346         int ret = 1;
347 
348         /* If quota is dirty already, we don't have to acquire dq_list_lock */
349         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
350                 return 1;
351 
352         spin_lock(&dq_list_lock);
353         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
354                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
355                                 info[dquot->dq_id.type].dqi_dirty_list);
356                 ret = 0;
357         }
358         spin_unlock(&dq_list_lock);
359         return ret;
360 }
361 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
362 
363 /* Dirtify all the dquots - this can block when journalling */
364 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
365 {
366         int ret, err, cnt;
367 
368         ret = err = 0;
369         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
370                 if (dquot[cnt])
371                         /* Even in case of error we have to continue */
372                         ret = mark_dquot_dirty(dquot[cnt]);
373                 if (!err)
374                         err = ret;
375         }
376         return err;
377 }
378 
379 static inline void dqput_all(struct dquot **dquot)
380 {
381         unsigned int cnt;
382 
383         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
384                 dqput(dquot[cnt]);
385 }
386 
387 /* This function needs dq_list_lock */
388 static inline int clear_dquot_dirty(struct dquot *dquot)
389 {
390         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
391                 return 0;
392         list_del_init(&dquot->dq_dirty);
393         return 1;
394 }
395 
396 void mark_info_dirty(struct super_block *sb, int type)
397 {
398         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
399 }
400 EXPORT_SYMBOL(mark_info_dirty);
401 
402 /*
403  *      Read dquot from disk and alloc space for it
404  */
405 
406 int dquot_acquire(struct dquot *dquot)
407 {
408         int ret = 0, ret2 = 0;
409         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
410 
411         mutex_lock(&dquot->dq_lock);
412         mutex_lock(&dqopt->dqio_mutex);
413         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
414                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
415         if (ret < 0)
416                 goto out_iolock;
417         set_bit(DQ_READ_B, &dquot->dq_flags);
418         /* Instantiate dquot if needed */
419         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
420                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
421                 /* Write the info if needed */
422                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
423                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
424                                         dquot->dq_sb, dquot->dq_id.type);
425                 }
426                 if (ret < 0)
427                         goto out_iolock;
428                 if (ret2 < 0) {
429                         ret = ret2;
430                         goto out_iolock;
431                 }
432         }
433         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
434 out_iolock:
435         mutex_unlock(&dqopt->dqio_mutex);
436         mutex_unlock(&dquot->dq_lock);
437         return ret;
438 }
439 EXPORT_SYMBOL(dquot_acquire);
440 
441 /*
442  *      Write dquot to disk
443  */
444 int dquot_commit(struct dquot *dquot)
445 {
446         int ret = 0;
447         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
448 
449         mutex_lock(&dqopt->dqio_mutex);
450         spin_lock(&dq_list_lock);
451         if (!clear_dquot_dirty(dquot)) {
452                 spin_unlock(&dq_list_lock);
453                 goto out_sem;
454         }
455         spin_unlock(&dq_list_lock);
456         /* Inactive dquot can be only if there was error during read/init
457          * => we have better not writing it */
458         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
459                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
460         else
461                 ret = -EIO;
462 out_sem:
463         mutex_unlock(&dqopt->dqio_mutex);
464         return ret;
465 }
466 EXPORT_SYMBOL(dquot_commit);
467 
468 /*
469  *      Release dquot
470  */
471 int dquot_release(struct dquot *dquot)
472 {
473         int ret = 0, ret2 = 0;
474         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
475 
476         mutex_lock(&dquot->dq_lock);
477         /* Check whether we are not racing with some other dqget() */
478         if (atomic_read(&dquot->dq_count) > 1)
479                 goto out_dqlock;
480         mutex_lock(&dqopt->dqio_mutex);
481         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
482                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
483                 /* Write the info */
484                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
485                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
486                                                 dquot->dq_sb, dquot->dq_id.type);
487                 }
488                 if (ret >= 0)
489                         ret = ret2;
490         }
491         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
492         mutex_unlock(&dqopt->dqio_mutex);
493 out_dqlock:
494         mutex_unlock(&dquot->dq_lock);
495         return ret;
496 }
497 EXPORT_SYMBOL(dquot_release);
498 
499 void dquot_destroy(struct dquot *dquot)
500 {
501         kmem_cache_free(dquot_cachep, dquot);
502 }
503 EXPORT_SYMBOL(dquot_destroy);
504 
505 static inline void do_destroy_dquot(struct dquot *dquot)
506 {
507         dquot->dq_sb->dq_op->destroy_dquot(dquot);
508 }
509 
510 /* Invalidate all dquots on the list. Note that this function is called after
511  * quota is disabled and pointers from inodes removed so there cannot be new
512  * quota users. There can still be some users of quotas due to inodes being
513  * just deleted or pruned by prune_icache() (those are not attached to any
514  * list) or parallel quotactl call. We have to wait for such users.
515  */
516 static void invalidate_dquots(struct super_block *sb, int type)
517 {
518         struct dquot *dquot, *tmp;
519 
520 restart:
521         spin_lock(&dq_list_lock);
522         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
523                 if (dquot->dq_sb != sb)
524                         continue;
525                 if (dquot->dq_id.type != type)
526                         continue;
527                 /* Wait for dquot users */
528                 if (atomic_read(&dquot->dq_count)) {
529                         DEFINE_WAIT(wait);
530 
531                         atomic_inc(&dquot->dq_count);
532                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
533                                         TASK_UNINTERRUPTIBLE);
534                         spin_unlock(&dq_list_lock);
535                         /* Once dqput() wakes us up, we know it's time to free
536                          * the dquot.
537                          * IMPORTANT: we rely on the fact that there is always
538                          * at most one process waiting for dquot to free.
539                          * Otherwise dq_count would be > 1 and we would never
540                          * wake up.
541                          */
542                         if (atomic_read(&dquot->dq_count) > 1)
543                                 schedule();
544                         finish_wait(&dquot->dq_wait_unused, &wait);
545                         dqput(dquot);
546                         /* At this moment dquot() need not exist (it could be
547                          * reclaimed by prune_dqcache(). Hence we must
548                          * restart. */
549                         goto restart;
550                 }
551                 /*
552                  * Quota now has no users and it has been written on last
553                  * dqput()
554                  */
555                 remove_dquot_hash(dquot);
556                 remove_free_dquot(dquot);
557                 remove_inuse(dquot);
558                 do_destroy_dquot(dquot);
559         }
560         spin_unlock(&dq_list_lock);
561 }
562 
563 /* Call callback for every active dquot on given filesystem */
564 int dquot_scan_active(struct super_block *sb,
565                       int (*fn)(struct dquot *dquot, unsigned long priv),
566                       unsigned long priv)
567 {
568         struct dquot *dquot, *old_dquot = NULL;
569         int ret = 0;
570 
571         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
572         spin_lock(&dq_list_lock);
573         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
574                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
575                         continue;
576                 if (dquot->dq_sb != sb)
577                         continue;
578                 /* Now we have active dquot so we can just increase use count */
579                 atomic_inc(&dquot->dq_count);
580                 spin_unlock(&dq_list_lock);
581                 dqstats_inc(DQST_LOOKUPS);
582                 dqput(old_dquot);
583                 old_dquot = dquot;
584                 /*
585                  * ->release_dquot() can be racing with us. Our reference
586                  * protects us from new calls to it so just wait for any
587                  * outstanding call and recheck the DQ_ACTIVE_B after that.
588                  */
589                 wait_on_dquot(dquot);
590                 if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
591                         ret = fn(dquot, priv);
592                         if (ret < 0)
593                                 goto out;
594                 }
595                 spin_lock(&dq_list_lock);
596                 /* We are safe to continue now because our dquot could not
597                  * be moved out of the inuse list while we hold the reference */
598         }
599         spin_unlock(&dq_list_lock);
600 out:
601         dqput(old_dquot);
602         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
603         return ret;
604 }
605 EXPORT_SYMBOL(dquot_scan_active);
606 
607 /* Write all dquot structures to quota files */
608 int dquot_writeback_dquots(struct super_block *sb, int type)
609 {
610         struct list_head *dirty;
611         struct dquot *dquot;
612         struct quota_info *dqopt = sb_dqopt(sb);
613         int cnt;
614         int err, ret = 0;
615 
616         mutex_lock(&dqopt->dqonoff_mutex);
617         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
618                 if (type != -1 && cnt != type)
619                         continue;
620                 if (!sb_has_quota_active(sb, cnt))
621                         continue;
622                 spin_lock(&dq_list_lock);
623                 dirty = &dqopt->info[cnt].dqi_dirty_list;
624                 while (!list_empty(dirty)) {
625                         dquot = list_first_entry(dirty, struct dquot,
626                                                  dq_dirty);
627                         /* Dirty and inactive can be only bad dquot... */
628                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
629                                 clear_dquot_dirty(dquot);
630                                 continue;
631                         }
632                         /* Now we have active dquot from which someone is
633                          * holding reference so we can safely just increase
634                          * use count */
635                         atomic_inc(&dquot->dq_count);
636                         spin_unlock(&dq_list_lock);
637                         dqstats_inc(DQST_LOOKUPS);
638                         err = sb->dq_op->write_dquot(dquot);
639                         if (!ret && err)
640                                 ret = err;
641                         dqput(dquot);
642                         spin_lock(&dq_list_lock);
643                 }
644                 spin_unlock(&dq_list_lock);
645         }
646 
647         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
648                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
649                     && info_dirty(&dqopt->info[cnt]))
650                         sb->dq_op->write_info(sb, cnt);
651         dqstats_inc(DQST_SYNCS);
652         mutex_unlock(&dqopt->dqonoff_mutex);
653 
654         return ret;
655 }
656 EXPORT_SYMBOL(dquot_writeback_dquots);
657 
658 /* Write all dquot structures to disk and make them visible from userspace */
659 int dquot_quota_sync(struct super_block *sb, int type)
660 {
661         struct quota_info *dqopt = sb_dqopt(sb);
662         int cnt;
663         int ret;
664 
665         ret = dquot_writeback_dquots(sb, type);
666         if (ret)
667                 return ret;
668         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
669                 return 0;
670 
671         /* This is not very clever (and fast) but currently I don't know about
672          * any other simple way of getting quota data to disk and we must get
673          * them there for userspace to be visible... */
674         if (sb->s_op->sync_fs)
675                 sb->s_op->sync_fs(sb, 1);
676         sync_blockdev(sb->s_bdev);
677 
678         /*
679          * Now when everything is written we can discard the pagecache so
680          * that userspace sees the changes.
681          */
682         mutex_lock(&dqopt->dqonoff_mutex);
683         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
684                 if (type != -1 && cnt != type)
685                         continue;
686                 if (!sb_has_quota_active(sb, cnt))
687                         continue;
688                 mutex_lock(&dqopt->files[cnt]->i_mutex);
689                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
690                 mutex_unlock(&dqopt->files[cnt]->i_mutex);
691         }
692         mutex_unlock(&dqopt->dqonoff_mutex);
693 
694         return 0;
695 }
696 EXPORT_SYMBOL(dquot_quota_sync);
697 
698 /* Free unused dquots from cache */
699 static void prune_dqcache(int count)
700 {
701         struct list_head *head;
702         struct dquot *dquot;
703 
704         head = free_dquots.prev;
705         while (head != &free_dquots && count) {
706                 dquot = list_entry(head, struct dquot, dq_free);
707                 remove_dquot_hash(dquot);
708                 remove_free_dquot(dquot);
709                 remove_inuse(dquot);
710                 do_destroy_dquot(dquot);
711                 count--;
712                 head = free_dquots.prev;
713         }
714 }
715 
716 /*
717  * This is called from kswapd when we think we need some
718  * more memory
719  */
720 static int shrink_dqcache_memory(struct shrinker *shrink,
721                                  struct shrink_control *sc)
722 {
723         int nr = sc->nr_to_scan;
724 
725         if (nr) {
726                 spin_lock(&dq_list_lock);
727                 prune_dqcache(nr);
728                 spin_unlock(&dq_list_lock);
729         }
730         return ((unsigned)
731                 percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS])
732                 /100) * sysctl_vfs_cache_pressure;
733 }
734 
735 static struct shrinker dqcache_shrinker = {
736         .shrink = shrink_dqcache_memory,
737         .seeks = DEFAULT_SEEKS,
738 };
739 
740 /*
741  * Put reference to dquot
742  * NOTE: If you change this function please check whether dqput_blocks() works right...
743  */
744 void dqput(struct dquot *dquot)
745 {
746         int ret;
747 
748         if (!dquot)
749                 return;
750 #ifdef CONFIG_QUOTA_DEBUG
751         if (!atomic_read(&dquot->dq_count)) {
752                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
753                             quotatypes[dquot->dq_id.type],
754                             from_kqid(&init_user_ns, dquot->dq_id));
755                 BUG();
756         }
757 #endif
758         dqstats_inc(DQST_DROPS);
759 we_slept:
760         spin_lock(&dq_list_lock);
761         if (atomic_read(&dquot->dq_count) > 1) {
762                 /* We have more than one user... nothing to do */
763                 atomic_dec(&dquot->dq_count);
764                 /* Releasing dquot during quotaoff phase? */
765                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
766                     atomic_read(&dquot->dq_count) == 1)
767                         wake_up(&dquot->dq_wait_unused);
768                 spin_unlock(&dq_list_lock);
769                 return;
770         }
771         /* Need to release dquot? */
772         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
773                 spin_unlock(&dq_list_lock);
774                 /* Commit dquot before releasing */
775                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
776                 if (ret < 0) {
777                         quota_error(dquot->dq_sb, "Can't write quota structure"
778                                     " (error %d). Quota may get out of sync!",
779                                     ret);
780                         /*
781                          * We clear dirty bit anyway, so that we avoid
782                          * infinite loop here
783                          */
784                         spin_lock(&dq_list_lock);
785                         clear_dquot_dirty(dquot);
786                         spin_unlock(&dq_list_lock);
787                 }
788                 goto we_slept;
789         }
790         /* Clear flag in case dquot was inactive (something bad happened) */
791         clear_dquot_dirty(dquot);
792         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
793                 spin_unlock(&dq_list_lock);
794                 dquot->dq_sb->dq_op->release_dquot(dquot);
795                 goto we_slept;
796         }
797         atomic_dec(&dquot->dq_count);
798 #ifdef CONFIG_QUOTA_DEBUG
799         /* sanity check */
800         BUG_ON(!list_empty(&dquot->dq_free));
801 #endif
802         put_dquot_last(dquot);
803         spin_unlock(&dq_list_lock);
804 }
805 EXPORT_SYMBOL(dqput);
806 
807 struct dquot *dquot_alloc(struct super_block *sb, int type)
808 {
809         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
810 }
811 EXPORT_SYMBOL(dquot_alloc);
812 
813 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
814 {
815         struct dquot *dquot;
816 
817         dquot = sb->dq_op->alloc_dquot(sb, type);
818         if(!dquot)
819                 return NULL;
820 
821         mutex_init(&dquot->dq_lock);
822         INIT_LIST_HEAD(&dquot->dq_free);
823         INIT_LIST_HEAD(&dquot->dq_inuse);
824         INIT_HLIST_NODE(&dquot->dq_hash);
825         INIT_LIST_HEAD(&dquot->dq_dirty);
826         init_waitqueue_head(&dquot->dq_wait_unused);
827         dquot->dq_sb = sb;
828         dquot->dq_id = make_kqid_invalid(type);
829         atomic_set(&dquot->dq_count, 1);
830 
831         return dquot;
832 }
833 
834 /*
835  * Get reference to dquot
836  *
837  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
838  * destroying our dquot by:
839  *   a) checking for quota flags under dq_list_lock and
840  *   b) getting a reference to dquot before we release dq_list_lock
841  */
842 struct dquot *dqget(struct super_block *sb, struct kqid qid)
843 {
844         unsigned int hashent = hashfn(sb, qid);
845         struct dquot *dquot = NULL, *empty = NULL;
846 
847         if (!sb_has_quota_active(sb, qid.type))
848                 return NULL;
849 we_slept:
850         spin_lock(&dq_list_lock);
851         spin_lock(&dq_state_lock);
852         if (!sb_has_quota_active(sb, qid.type)) {
853                 spin_unlock(&dq_state_lock);
854                 spin_unlock(&dq_list_lock);
855                 goto out;
856         }
857         spin_unlock(&dq_state_lock);
858 
859         dquot = find_dquot(hashent, sb, qid);
860         if (!dquot) {
861                 if (!empty) {
862                         spin_unlock(&dq_list_lock);
863                         empty = get_empty_dquot(sb, qid.type);
864                         if (!empty)
865                                 schedule();     /* Try to wait for a moment... */
866                         goto we_slept;
867                 }
868                 dquot = empty;
869                 empty = NULL;
870                 dquot->dq_id = qid;
871                 /* all dquots go on the inuse_list */
872                 put_inuse(dquot);
873                 /* hash it first so it can be found */
874                 insert_dquot_hash(dquot);
875                 spin_unlock(&dq_list_lock);
876                 dqstats_inc(DQST_LOOKUPS);
877         } else {
878                 if (!atomic_read(&dquot->dq_count))
879                         remove_free_dquot(dquot);
880                 atomic_inc(&dquot->dq_count);
881                 spin_unlock(&dq_list_lock);
882                 dqstats_inc(DQST_CACHE_HITS);
883                 dqstats_inc(DQST_LOOKUPS);
884         }
885         /* Wait for dq_lock - after this we know that either dquot_release() is
886          * already finished or it will be canceled due to dq_count > 1 test */
887         wait_on_dquot(dquot);
888         /* Read the dquot / allocate space in quota file */
889         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) &&
890             sb->dq_op->acquire_dquot(dquot) < 0) {
891                 dqput(dquot);
892                 dquot = NULL;
893                 goto out;
894         }
895 #ifdef CONFIG_QUOTA_DEBUG
896         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
897 #endif
898 out:
899         if (empty)
900                 do_destroy_dquot(empty);
901 
902         return dquot;
903 }
904 EXPORT_SYMBOL(dqget);
905 
906 static int dqinit_needed(struct inode *inode, int type)
907 {
908         int cnt;
909 
910         if (IS_NOQUOTA(inode))
911                 return 0;
912         if (type != -1)
913                 return !inode->i_dquot[type];
914         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
915                 if (!inode->i_dquot[cnt])
916                         return 1;
917         return 0;
918 }
919 
920 /* This routine is guarded by dqonoff_mutex mutex */
921 static void add_dquot_ref(struct super_block *sb, int type)
922 {
923         struct inode *inode, *old_inode = NULL;
924 #ifdef CONFIG_QUOTA_DEBUG
925         int reserved = 0;
926 #endif
927 
928         spin_lock(&inode_sb_list_lock);
929         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
930                 spin_lock(&inode->i_lock);
931                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
932                     !atomic_read(&inode->i_writecount) ||
933                     !dqinit_needed(inode, type)) {
934                         spin_unlock(&inode->i_lock);
935                         continue;
936                 }
937                 __iget(inode);
938                 spin_unlock(&inode->i_lock);
939                 spin_unlock(&inode_sb_list_lock);
940 
941 #ifdef CONFIG_QUOTA_DEBUG
942                 if (unlikely(inode_get_rsv_space(inode) > 0))
943                         reserved = 1;
944 #endif
945                 iput(old_inode);
946                 __dquot_initialize(inode, type);
947 
948                 /*
949                  * We hold a reference to 'inode' so it couldn't have been
950                  * removed from s_inodes list while we dropped the
951                  * inode_sb_list_lock We cannot iput the inode now as we can be
952                  * holding the last reference and we cannot iput it under
953                  * inode_sb_list_lock. So we keep the reference and iput it
954                  * later.
955                  */
956                 old_inode = inode;
957                 spin_lock(&inode_sb_list_lock);
958         }
959         spin_unlock(&inode_sb_list_lock);
960         iput(old_inode);
961 
962 #ifdef CONFIG_QUOTA_DEBUG
963         if (reserved) {
964                 quota_error(sb, "Writes happened before quota was turned on "
965                         "thus quota information is probably inconsistent. "
966                         "Please run quotacheck(8)");
967         }
968 #endif
969 }
970 
971 /*
972  * Return 0 if dqput() won't block.
973  * (note that 1 doesn't necessarily mean blocking)
974  */
975 static inline int dqput_blocks(struct dquot *dquot)
976 {
977         if (atomic_read(&dquot->dq_count) <= 1)
978                 return 1;
979         return 0;
980 }
981 
982 /*
983  * Remove references to dquots from inode and add dquot to list for freeing
984  * if we have the last reference to dquot
985  * We can't race with anybody because we hold dqptr_sem for writing...
986  */
987 static int remove_inode_dquot_ref(struct inode *inode, int type,
988                                   struct list_head *tofree_head)
989 {
990         struct dquot *dquot = inode->i_dquot[type];
991 
992         inode->i_dquot[type] = NULL;
993         if (dquot) {
994                 if (dqput_blocks(dquot)) {
995 #ifdef CONFIG_QUOTA_DEBUG
996                         if (atomic_read(&dquot->dq_count) != 1)
997                                 quota_error(inode->i_sb, "Adding dquot with "
998                                             "dq_count %d to dispose list",
999                                             atomic_read(&dquot->dq_count));
1000 #endif
1001                         spin_lock(&dq_list_lock);
1002                         /* As dquot must have currently users it can't be on
1003                          * the free list... */
1004                         list_add(&dquot->dq_free, tofree_head);
1005                         spin_unlock(&dq_list_lock);
1006                         return 1;
1007                 }
1008                 else
1009                         dqput(dquot);   /* We have guaranteed we won't block */
1010         }
1011         return 0;
1012 }
1013 
1014 /*
1015  * Free list of dquots
1016  * Dquots are removed from inodes and no new references can be got so we are
1017  * the only ones holding reference
1018  */
1019 static void put_dquot_list(struct list_head *tofree_head)
1020 {
1021         struct list_head *act_head;
1022         struct dquot *dquot;
1023 
1024         act_head = tofree_head->next;
1025         while (act_head != tofree_head) {
1026                 dquot = list_entry(act_head, struct dquot, dq_free);
1027                 act_head = act_head->next;
1028                 /* Remove dquot from the list so we won't have problems... */
1029                 list_del_init(&dquot->dq_free);
1030                 dqput(dquot);
1031         }
1032 }
1033 
1034 static void remove_dquot_ref(struct super_block *sb, int type,
1035                 struct list_head *tofree_head)
1036 {
1037         struct inode *inode;
1038         int reserved = 0;
1039 
1040         spin_lock(&inode_sb_list_lock);
1041         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1042                 /*
1043                  *  We have to scan also I_NEW inodes because they can already
1044                  *  have quota pointer initialized. Luckily, we need to touch
1045                  *  only quota pointers and these have separate locking
1046                  *  (dqptr_sem).
1047                  */
1048                 if (!IS_NOQUOTA(inode)) {
1049                         if (unlikely(inode_get_rsv_space(inode) > 0))
1050                                 reserved = 1;
1051                         remove_inode_dquot_ref(inode, type, tofree_head);
1052                 }
1053         }
1054         spin_unlock(&inode_sb_list_lock);
1055 #ifdef CONFIG_QUOTA_DEBUG
1056         if (reserved) {
1057                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1058                         " was disabled thus quota information is probably "
1059                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1060         }
1061 #endif
1062 }
1063 
1064 /* Gather all references from inodes and drop them */
1065 static void drop_dquot_ref(struct super_block *sb, int type)
1066 {
1067         LIST_HEAD(tofree_head);
1068 
1069         if (sb->dq_op) {
1070                 down_write(&sb_dqopt(sb)->dqptr_sem);
1071                 remove_dquot_ref(sb, type, &tofree_head);
1072                 up_write(&sb_dqopt(sb)->dqptr_sem);
1073                 put_dquot_list(&tofree_head);
1074         }
1075 }
1076 
1077 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
1078 {
1079         dquot->dq_dqb.dqb_curinodes += number;
1080 }
1081 
1082 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
1083 {
1084         dquot->dq_dqb.dqb_curspace += number;
1085 }
1086 
1087 static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
1088 {
1089         dquot->dq_dqb.dqb_rsvspace += number;
1090 }
1091 
1092 /*
1093  * Claim reserved quota space
1094  */
1095 static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number)
1096 {
1097         if (dquot->dq_dqb.dqb_rsvspace < number) {
1098                 WARN_ON_ONCE(1);
1099                 number = dquot->dq_dqb.dqb_rsvspace;
1100         }
1101         dquot->dq_dqb.dqb_curspace += number;
1102         dquot->dq_dqb.dqb_rsvspace -= number;
1103 }
1104 
1105 static void dquot_reclaim_reserved_space(struct dquot *dquot, qsize_t number)
1106 {
1107         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1108                 number = dquot->dq_dqb.dqb_curspace;
1109         dquot->dq_dqb.dqb_rsvspace += number;
1110         dquot->dq_dqb.dqb_curspace -= number;
1111 }
1112 
1113 static inline
1114 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1115 {
1116         if (dquot->dq_dqb.dqb_rsvspace >= number)
1117                 dquot->dq_dqb.dqb_rsvspace -= number;
1118         else {
1119                 WARN_ON_ONCE(1);
1120                 dquot->dq_dqb.dqb_rsvspace = 0;
1121         }
1122 }
1123 
1124 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1125 {
1126         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1127             dquot->dq_dqb.dqb_curinodes >= number)
1128                 dquot->dq_dqb.dqb_curinodes -= number;
1129         else
1130                 dquot->dq_dqb.dqb_curinodes = 0;
1131         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1132                 dquot->dq_dqb.dqb_itime = (time_t) 0;
1133         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1134 }
1135 
1136 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1137 {
1138         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1139             dquot->dq_dqb.dqb_curspace >= number)
1140                 dquot->dq_dqb.dqb_curspace -= number;
1141         else
1142                 dquot->dq_dqb.dqb_curspace = 0;
1143         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1144                 dquot->dq_dqb.dqb_btime = (time_t) 0;
1145         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1146 }
1147 
1148 struct dquot_warn {
1149         struct super_block *w_sb;
1150         struct kqid w_dq_id;
1151         short w_type;
1152 };
1153 
1154 static int warning_issued(struct dquot *dquot, const int warntype)
1155 {
1156         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1157                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1158                 ((warntype == QUOTA_NL_IHARDWARN ||
1159                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1160 
1161         if (!flag)
1162                 return 0;
1163         return test_and_set_bit(flag, &dquot->dq_flags);
1164 }
1165 
1166 #ifdef CONFIG_PRINT_QUOTA_WARNING
1167 static int flag_print_warnings = 1;
1168 
1169 static int need_print_warning(struct dquot_warn *warn)
1170 {
1171         if (!flag_print_warnings)
1172                 return 0;
1173 
1174         switch (warn->w_dq_id.type) {
1175                 case USRQUOTA:
1176                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1177                 case GRPQUOTA:
1178                         return in_group_p(warn->w_dq_id.gid);
1179                 case PRJQUOTA:  /* Never taken... Just make gcc happy */
1180                         return 0;
1181         }
1182         return 0;
1183 }
1184 
1185 /* Print warning to user which exceeded quota */
1186 static void print_warning(struct dquot_warn *warn)
1187 {
1188         char *msg = NULL;
1189         struct tty_struct *tty;
1190         int warntype = warn->w_type;
1191 
1192         if (warntype == QUOTA_NL_IHARDBELOW ||
1193             warntype == QUOTA_NL_ISOFTBELOW ||
1194             warntype == QUOTA_NL_BHARDBELOW ||
1195             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1196                 return;
1197 
1198         tty = get_current_tty();
1199         if (!tty)
1200                 return;
1201         tty_write_message(tty, warn->w_sb->s_id);
1202         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1203                 tty_write_message(tty, ": warning, ");
1204         else
1205                 tty_write_message(tty, ": write failed, ");
1206         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1207         switch (warntype) {
1208                 case QUOTA_NL_IHARDWARN:
1209                         msg = " file limit reached.\r\n";
1210                         break;
1211                 case QUOTA_NL_ISOFTLONGWARN:
1212                         msg = " file quota exceeded too long.\r\n";
1213                         break;
1214                 case QUOTA_NL_ISOFTWARN:
1215                         msg = " file quota exceeded.\r\n";
1216                         break;
1217                 case QUOTA_NL_BHARDWARN:
1218                         msg = " block limit reached.\r\n";
1219                         break;
1220                 case QUOTA_NL_BSOFTLONGWARN:
1221                         msg = " block quota exceeded too long.\r\n";
1222                         break;
1223                 case QUOTA_NL_BSOFTWARN:
1224                         msg = " block quota exceeded.\r\n";
1225                         break;
1226         }
1227         tty_write_message(tty, msg);
1228         tty_kref_put(tty);
1229 }
1230 #endif
1231 
1232 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1233                             int warntype)
1234 {
1235         if (warning_issued(dquot, warntype))
1236                 return;
1237         warn->w_type = warntype;
1238         warn->w_sb = dquot->dq_sb;
1239         warn->w_dq_id = dquot->dq_id;
1240 }
1241 
1242 /*
1243  * Write warnings to the console and send warning messages over netlink.
1244  *
1245  * Note that this function can call into tty and networking code.
1246  */
1247 static void flush_warnings(struct dquot_warn *warn)
1248 {
1249         int i;
1250 
1251         for (i = 0; i < MAXQUOTAS; i++) {
1252                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1253                         continue;
1254 #ifdef CONFIG_PRINT_QUOTA_WARNING
1255                 print_warning(&warn[i]);
1256 #endif
1257                 quota_send_warning(warn[i].w_dq_id,
1258                                    warn[i].w_sb->s_dev, warn[i].w_type);
1259         }
1260 }
1261 
1262 static int ignore_hardlimit(struct dquot *dquot)
1263 {
1264         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1265 
1266         return capable(CAP_SYS_RESOURCE) &&
1267                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1268                 !(info->dqi_flags & V1_DQF_RSQUASH));
1269 }
1270 
1271 /* needs dq_data_lock */
1272 static int check_idq(struct dquot *dquot, qsize_t inodes,
1273                      struct dquot_warn *warn)
1274 {
1275         qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1276 
1277         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1278             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1279                 return 0;
1280 
1281         if (dquot->dq_dqb.dqb_ihardlimit &&
1282             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1283             !ignore_hardlimit(dquot)) {
1284                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1285                 return -EDQUOT;
1286         }
1287 
1288         if (dquot->dq_dqb.dqb_isoftlimit &&
1289             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1290             dquot->dq_dqb.dqb_itime &&
1291             get_seconds() >= dquot->dq_dqb.dqb_itime &&
1292             !ignore_hardlimit(dquot)) {
1293                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1294                 return -EDQUOT;
1295         }
1296 
1297         if (dquot->dq_dqb.dqb_isoftlimit &&
1298             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1299             dquot->dq_dqb.dqb_itime == 0) {
1300                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
1301                 dquot->dq_dqb.dqb_itime = get_seconds() +
1302                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
1303         }
1304 
1305         return 0;
1306 }
1307 
1308 /* needs dq_data_lock */
1309 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc,
1310                      struct dquot_warn *warn)
1311 {
1312         qsize_t tspace;
1313         struct super_block *sb = dquot->dq_sb;
1314 
1315         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1316             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1317                 return 0;
1318 
1319         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1320                 + space;
1321 
1322         if (dquot->dq_dqb.dqb_bhardlimit &&
1323             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1324             !ignore_hardlimit(dquot)) {
1325                 if (!prealloc)
1326                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1327                 return -EDQUOT;
1328         }
1329 
1330         if (dquot->dq_dqb.dqb_bsoftlimit &&
1331             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1332             dquot->dq_dqb.dqb_btime &&
1333             get_seconds() >= dquot->dq_dqb.dqb_btime &&
1334             !ignore_hardlimit(dquot)) {
1335                 if (!prealloc)
1336                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1337                 return -EDQUOT;
1338         }
1339 
1340         if (dquot->dq_dqb.dqb_bsoftlimit &&
1341             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1342             dquot->dq_dqb.dqb_btime == 0) {
1343                 if (!prealloc) {
1344                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1345                         dquot->dq_dqb.dqb_btime = get_seconds() +
1346                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1347                 }
1348                 else
1349                         /*
1350                          * We don't allow preallocation to exceed softlimit so exceeding will
1351                          * be always printed
1352                          */
1353                         return -EDQUOT;
1354         }
1355 
1356         return 0;
1357 }
1358 
1359 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1360 {
1361         qsize_t newinodes;
1362 
1363         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1364             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1365             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1366                 return QUOTA_NL_NOWARN;
1367 
1368         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1369         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1370                 return QUOTA_NL_ISOFTBELOW;
1371         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1372             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1373                 return QUOTA_NL_IHARDBELOW;
1374         return QUOTA_NL_NOWARN;
1375 }
1376 
1377 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1378 {
1379         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1380             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1381                 return QUOTA_NL_NOWARN;
1382 
1383         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1384                 return QUOTA_NL_BSOFTBELOW;
1385         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1386             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1387                 return QUOTA_NL_BHARDBELOW;
1388         return QUOTA_NL_NOWARN;
1389 }
1390 
1391 static int dquot_active(const struct inode *inode)
1392 {
1393         struct super_block *sb = inode->i_sb;
1394 
1395         if (IS_NOQUOTA(inode))
1396                 return 0;
1397         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1398 }
1399 
1400 /*
1401  * Initialize quota pointers in inode
1402  *
1403  * We do things in a bit complicated way but by that we avoid calling
1404  * dqget() and thus filesystem callbacks under dqptr_sem.
1405  *
1406  * It is better to call this function outside of any transaction as it
1407  * might need a lot of space in journal for dquot structure allocation.
1408  */
1409 static void __dquot_initialize(struct inode *inode, int type)
1410 {
1411         int cnt;
1412         struct dquot *got[MAXQUOTAS];
1413         struct super_block *sb = inode->i_sb;
1414         qsize_t rsv;
1415 
1416         /* First test before acquiring mutex - solves deadlocks when we
1417          * re-enter the quota code and are already holding the mutex */
1418         if (!dquot_active(inode))
1419                 return;
1420 
1421         /* First get references to structures we might need. */
1422         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1423                 struct kqid qid;
1424                 got[cnt] = NULL;
1425                 if (type != -1 && cnt != type)
1426                         continue;
1427                 switch (cnt) {
1428                 case USRQUOTA:
1429                         qid = make_kqid_uid(inode->i_uid);
1430                         break;
1431                 case GRPQUOTA:
1432                         qid = make_kqid_gid(inode->i_gid);
1433                         break;
1434                 }
1435                 got[cnt] = dqget(sb, qid);
1436         }
1437 
1438         down_write(&sb_dqopt(sb)->dqptr_sem);
1439         if (IS_NOQUOTA(inode))
1440                 goto out_err;
1441         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1442                 if (type != -1 && cnt != type)
1443                         continue;
1444                 /* Avoid races with quotaoff() */
1445                 if (!sb_has_quota_active(sb, cnt))
1446                         continue;
1447                 /* We could race with quotaon or dqget() could have failed */
1448                 if (!got[cnt])
1449                         continue;
1450                 if (!inode->i_dquot[cnt]) {
1451                         inode->i_dquot[cnt] = got[cnt];
1452                         got[cnt] = NULL;
1453                         /*
1454                          * Make quota reservation system happy if someone
1455                          * did a write before quota was turned on
1456                          */
1457                         rsv = inode_get_rsv_space(inode);
1458                         if (unlikely(rsv)) {
1459                                 spin_lock(&dq_data_lock);
1460                                 dquot_resv_space(inode->i_dquot[cnt], rsv);
1461                                 spin_unlock(&dq_data_lock);
1462                         }
1463                 }
1464         }
1465 out_err:
1466         up_write(&sb_dqopt(sb)->dqptr_sem);
1467         /* Drop unused references */
1468         dqput_all(got);
1469 }
1470 
1471 void dquot_initialize(struct inode *inode)
1472 {
1473         __dquot_initialize(inode, -1);
1474 }
1475 EXPORT_SYMBOL(dquot_initialize);
1476 
1477 /*
1478  *      Release all quotas referenced by inode
1479  */
1480 static void __dquot_drop(struct inode *inode)
1481 {
1482         int cnt;
1483         struct dquot *put[MAXQUOTAS];
1484 
1485         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1486         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1487                 put[cnt] = inode->i_dquot[cnt];
1488                 inode->i_dquot[cnt] = NULL;
1489         }
1490         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1491         dqput_all(put);
1492 }
1493 
1494 void dquot_drop(struct inode *inode)
1495 {
1496         int cnt;
1497 
1498         if (IS_NOQUOTA(inode))
1499                 return;
1500 
1501         /*
1502          * Test before calling to rule out calls from proc and such
1503          * where we are not allowed to block. Note that this is
1504          * actually reliable test even without the lock - the caller
1505          * must assure that nobody can come after the DQUOT_DROP and
1506          * add quota pointers back anyway.
1507          */
1508         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1509                 if (inode->i_dquot[cnt])
1510                         break;
1511         }
1512 
1513         if (cnt < MAXQUOTAS)
1514                 __dquot_drop(inode);
1515 }
1516 EXPORT_SYMBOL(dquot_drop);
1517 
1518 /*
1519  * inode_reserved_space is managed internally by quota, and protected by
1520  * i_lock similar to i_blocks+i_bytes.
1521  */
1522 static qsize_t *inode_reserved_space(struct inode * inode)
1523 {
1524         /* Filesystem must explicitly define it's own method in order to use
1525          * quota reservation interface */
1526         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1527         return inode->i_sb->dq_op->get_reserved_space(inode);
1528 }
1529 
1530 void inode_add_rsv_space(struct inode *inode, qsize_t number)
1531 {
1532         spin_lock(&inode->i_lock);
1533         *inode_reserved_space(inode) += number;
1534         spin_unlock(&inode->i_lock);
1535 }
1536 EXPORT_SYMBOL(inode_add_rsv_space);
1537 
1538 void inode_claim_rsv_space(struct inode *inode, qsize_t number)
1539 {
1540         spin_lock(&inode->i_lock);
1541         *inode_reserved_space(inode) -= number;
1542         __inode_add_bytes(inode, number);
1543         spin_unlock(&inode->i_lock);
1544 }
1545 EXPORT_SYMBOL(inode_claim_rsv_space);
1546 
1547 void inode_reclaim_rsv_space(struct inode *inode, qsize_t number)
1548 {
1549         spin_lock(&inode->i_lock);
1550         *inode_reserved_space(inode) += number;
1551         __inode_sub_bytes(inode, number);
1552         spin_unlock(&inode->i_lock);
1553 }
1554 EXPORT_SYMBOL(inode_reclaim_rsv_space);
1555 
1556 void inode_sub_rsv_space(struct inode *inode, qsize_t number)
1557 {
1558         spin_lock(&inode->i_lock);
1559         *inode_reserved_space(inode) -= number;
1560         spin_unlock(&inode->i_lock);
1561 }
1562 EXPORT_SYMBOL(inode_sub_rsv_space);
1563 
1564 static qsize_t inode_get_rsv_space(struct inode *inode)
1565 {
1566         qsize_t ret;
1567 
1568         if (!inode->i_sb->dq_op->get_reserved_space)
1569                 return 0;
1570         spin_lock(&inode->i_lock);
1571         ret = *inode_reserved_space(inode);
1572         spin_unlock(&inode->i_lock);
1573         return ret;
1574 }
1575 
1576 static void inode_incr_space(struct inode *inode, qsize_t number,
1577                                 int reserve)
1578 {
1579         if (reserve)
1580                 inode_add_rsv_space(inode, number);
1581         else
1582                 inode_add_bytes(inode, number);
1583 }
1584 
1585 static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
1586 {
1587         if (reserve)
1588                 inode_sub_rsv_space(inode, number);
1589         else
1590                 inode_sub_bytes(inode, number);
1591 }
1592 
1593 /*
1594  * This functions updates i_blocks+i_bytes fields and quota information
1595  * (together with appropriate checks).
1596  *
1597  * NOTE: We absolutely rely on the fact that caller dirties the inode
1598  * (usually helpers in quotaops.h care about this) and holds a handle for
1599  * the current transaction so that dquot write and inode write go into the
1600  * same transaction.
1601  */
1602 
1603 /*
1604  * This operation can block, but only after everything is updated
1605  */
1606 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1607 {
1608         int cnt, ret = 0;
1609         struct dquot_warn warn[MAXQUOTAS];
1610         struct dquot **dquots = inode->i_dquot;
1611         int reserve = flags & DQUOT_SPACE_RESERVE;
1612 
1613         /*
1614          * First test before acquiring mutex - solves deadlocks when we
1615          * re-enter the quota code and are already holding the mutex
1616          */
1617         if (!dquot_active(inode)) {
1618                 inode_incr_space(inode, number, reserve);
1619                 goto out;
1620         }
1621 
1622         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1623                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1624 
1625         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1626         spin_lock(&dq_data_lock);
1627         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1628                 if (!dquots[cnt])
1629                         continue;
1630                 ret = check_bdq(dquots[cnt], number,
1631                                 !(flags & DQUOT_SPACE_WARN), &warn[cnt]);
1632                 if (ret && !(flags & DQUOT_SPACE_NOFAIL)) {
1633                         spin_unlock(&dq_data_lock);
1634                         goto out_flush_warn;
1635                 }
1636         }
1637         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1638                 if (!dquots[cnt])
1639                         continue;
1640                 if (reserve)
1641                         dquot_resv_space(dquots[cnt], number);
1642                 else
1643                         dquot_incr_space(dquots[cnt], number);
1644         }
1645         inode_incr_space(inode, number, reserve);
1646         spin_unlock(&dq_data_lock);
1647 
1648         if (reserve)
1649                 goto out_flush_warn;
1650         mark_all_dquot_dirty(dquots);
1651 out_flush_warn:
1652         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1653         flush_warnings(warn);
1654 out:
1655         return ret;
1656 }
1657 EXPORT_SYMBOL(__dquot_alloc_space);
1658 
1659 /*
1660  * This operation can block, but only after everything is updated
1661  */
1662 int dquot_alloc_inode(const struct inode *inode)
1663 {
1664         int cnt, ret = 0;
1665         struct dquot_warn warn[MAXQUOTAS];
1666         struct dquot * const *dquots = inode->i_dquot;
1667 
1668         /* First test before acquiring mutex - solves deadlocks when we
1669          * re-enter the quota code and are already holding the mutex */
1670         if (!dquot_active(inode))
1671                 return 0;
1672         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1673                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1674         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1675         spin_lock(&dq_data_lock);
1676         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1677                 if (!dquots[cnt])
1678                         continue;
1679                 ret = check_idq(dquots[cnt], 1, &warn[cnt]);
1680                 if (ret)
1681                         goto warn_put_all;
1682         }
1683 
1684         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1685                 if (!dquots[cnt])
1686                         continue;
1687                 dquot_incr_inodes(dquots[cnt], 1);
1688         }
1689 
1690 warn_put_all:
1691         spin_unlock(&dq_data_lock);
1692         if (ret == 0)
1693                 mark_all_dquot_dirty(dquots);
1694         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1695         flush_warnings(warn);
1696         return ret;
1697 }
1698 EXPORT_SYMBOL(dquot_alloc_inode);
1699 
1700 /*
1701  * Convert in-memory reserved quotas to real consumed quotas
1702  */
1703 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1704 {
1705         int cnt;
1706 
1707         if (!dquot_active(inode)) {
1708                 inode_claim_rsv_space(inode, number);
1709                 return 0;
1710         }
1711 
1712         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1713         spin_lock(&dq_data_lock);
1714         /* Claim reserved quotas to allocated quotas */
1715         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1716                 if (inode->i_dquot[cnt])
1717                         dquot_claim_reserved_space(inode->i_dquot[cnt],
1718                                                         number);
1719         }
1720         /* Update inode bytes */
1721         inode_claim_rsv_space(inode, number);
1722         spin_unlock(&dq_data_lock);
1723         mark_all_dquot_dirty(inode->i_dquot);
1724         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1725         return 0;
1726 }
1727 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1728 
1729 /*
1730  * Convert allocated space back to in-memory reserved quotas
1731  */
1732 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1733 {
1734         int cnt;
1735 
1736         if (!dquot_active(inode)) {
1737                 inode_reclaim_rsv_space(inode, number);
1738                 return;
1739         }
1740 
1741         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1742         spin_lock(&dq_data_lock);
1743         /* Claim reserved quotas to allocated quotas */
1744         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1745                 if (inode->i_dquot[cnt])
1746                         dquot_reclaim_reserved_space(inode->i_dquot[cnt],
1747                                                      number);
1748         }
1749         /* Update inode bytes */
1750         inode_reclaim_rsv_space(inode, number);
1751         spin_unlock(&dq_data_lock);
1752         mark_all_dquot_dirty(inode->i_dquot);
1753         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1754         return;
1755 }
1756 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1757 
1758 /*
1759  * This operation can block, but only after everything is updated
1760  */
1761 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1762 {
1763         unsigned int cnt;
1764         struct dquot_warn warn[MAXQUOTAS];
1765         struct dquot **dquots = inode->i_dquot;
1766         int reserve = flags & DQUOT_SPACE_RESERVE;
1767 
1768         /* First test before acquiring mutex - solves deadlocks when we
1769          * re-enter the quota code and are already holding the mutex */
1770         if (!dquot_active(inode)) {
1771                 inode_decr_space(inode, number, reserve);
1772                 return;
1773         }
1774 
1775         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1776         spin_lock(&dq_data_lock);
1777         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1778                 int wtype;
1779 
1780                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1781                 if (!dquots[cnt])
1782                         continue;
1783                 wtype = info_bdq_free(dquots[cnt], number);
1784                 if (wtype != QUOTA_NL_NOWARN)
1785                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1786                 if (reserve)
1787                         dquot_free_reserved_space(dquots[cnt], number);
1788                 else
1789                         dquot_decr_space(dquots[cnt], number);
1790         }
1791         inode_decr_space(inode, number, reserve);
1792         spin_unlock(&dq_data_lock);
1793 
1794         if (reserve)
1795                 goto out_unlock;
1796         mark_all_dquot_dirty(dquots);
1797 out_unlock:
1798         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1799         flush_warnings(warn);
1800 }
1801 EXPORT_SYMBOL(__dquot_free_space);
1802 
1803 /*
1804  * This operation can block, but only after everything is updated
1805  */
1806 void dquot_free_inode(const struct inode *inode)
1807 {
1808         unsigned int cnt;
1809         struct dquot_warn warn[MAXQUOTAS];
1810         struct dquot * const *dquots = inode->i_dquot;
1811 
1812         /* First test before acquiring mutex - solves deadlocks when we
1813          * re-enter the quota code and are already holding the mutex */
1814         if (!dquot_active(inode))
1815                 return;
1816 
1817         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1818         spin_lock(&dq_data_lock);
1819         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1820                 int wtype;
1821 
1822                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1823                 if (!dquots[cnt])
1824                         continue;
1825                 wtype = info_idq_free(dquots[cnt], 1);
1826                 if (wtype != QUOTA_NL_NOWARN)
1827                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1828                 dquot_decr_inodes(dquots[cnt], 1);
1829         }
1830         spin_unlock(&dq_data_lock);
1831         mark_all_dquot_dirty(dquots);
1832         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1833         flush_warnings(warn);
1834 }
1835 EXPORT_SYMBOL(dquot_free_inode);
1836 
1837 /*
1838  * Transfer the number of inode and blocks from one diskquota to an other.
1839  * On success, dquot references in transfer_to are consumed and references
1840  * to original dquots that need to be released are placed there. On failure,
1841  * references are kept untouched.
1842  *
1843  * This operation can block, but only after everything is updated
1844  * A transaction must be started when entering this function.
1845  *
1846  */
1847 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1848 {
1849         qsize_t space, cur_space;
1850         qsize_t rsv_space = 0;
1851         struct dquot *transfer_from[MAXQUOTAS] = {};
1852         int cnt, ret = 0;
1853         char is_valid[MAXQUOTAS] = {};
1854         struct dquot_warn warn_to[MAXQUOTAS];
1855         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1856         struct dquot_warn warn_from_space[MAXQUOTAS];
1857 
1858         /* First test before acquiring mutex - solves deadlocks when we
1859          * re-enter the quota code and are already holding the mutex */
1860         if (IS_NOQUOTA(inode))
1861                 return 0;
1862         /* Initialize the arrays */
1863         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1864                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
1865                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
1866                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
1867         }
1868         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1869         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1870                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1871                 return 0;
1872         }
1873         spin_lock(&dq_data_lock);
1874         cur_space = inode_get_bytes(inode);
1875         rsv_space = inode_get_rsv_space(inode);
1876         space = cur_space + rsv_space;
1877         /* Build the transfer_from list and check the limits */
1878         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1879                 /*
1880                  * Skip changes for same uid or gid or for turned off quota-type.
1881                  */
1882                 if (!transfer_to[cnt])
1883                         continue;
1884                 /* Avoid races with quotaoff() */
1885                 if (!sb_has_quota_active(inode->i_sb, cnt))
1886                         continue;
1887                 is_valid[cnt] = 1;
1888                 transfer_from[cnt] = inode->i_dquot[cnt];
1889                 ret = check_idq(transfer_to[cnt], 1, &warn_to[cnt]);
1890                 if (ret)
1891                         goto over_quota;
1892                 ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
1893                 if (ret)
1894                         goto over_quota;
1895         }
1896 
1897         /*
1898          * Finally perform the needed transfer from transfer_from to transfer_to
1899          */
1900         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1901                 if (!is_valid[cnt])
1902                         continue;
1903                 /* Due to IO error we might not have transfer_from[] structure */
1904                 if (transfer_from[cnt]) {
1905                         int wtype;
1906                         wtype = info_idq_free(transfer_from[cnt], 1);
1907                         if (wtype != QUOTA_NL_NOWARN)
1908                                 prepare_warning(&warn_from_inodes[cnt],
1909                                                 transfer_from[cnt], wtype);
1910                         wtype = info_bdq_free(transfer_from[cnt], space);
1911                         if (wtype != QUOTA_NL_NOWARN)
1912                                 prepare_warning(&warn_from_space[cnt],
1913                                                 transfer_from[cnt], wtype);
1914                         dquot_decr_inodes(transfer_from[cnt], 1);
1915                         dquot_decr_space(transfer_from[cnt], cur_space);
1916                         dquot_free_reserved_space(transfer_from[cnt],
1917                                                   rsv_space);
1918                 }
1919 
1920                 dquot_incr_inodes(transfer_to[cnt], 1);
1921                 dquot_incr_space(transfer_to[cnt], cur_space);
1922                 dquot_resv_space(transfer_to[cnt], rsv_space);
1923 
1924                 inode->i_dquot[cnt] = transfer_to[cnt];
1925         }
1926         spin_unlock(&dq_data_lock);
1927         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1928 
1929         mark_all_dquot_dirty(transfer_from);
1930         mark_all_dquot_dirty(transfer_to);
1931         flush_warnings(warn_to);
1932         flush_warnings(warn_from_inodes);
1933         flush_warnings(warn_from_space);
1934         /* Pass back references to put */
1935         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1936                 if (is_valid[cnt])
1937                         transfer_to[cnt] = transfer_from[cnt];
1938         return 0;
1939 over_quota:
1940         spin_unlock(&dq_data_lock);
1941         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1942         flush_warnings(warn_to);
1943         return ret;
1944 }
1945 EXPORT_SYMBOL(__dquot_transfer);
1946 
1947 /* Wrapper for transferring ownership of an inode for uid/gid only
1948  * Called from FSXXX_setattr()
1949  */
1950 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1951 {
1952         struct dquot *transfer_to[MAXQUOTAS] = {};
1953         struct super_block *sb = inode->i_sb;
1954         int ret;
1955 
1956         if (!dquot_active(inode))
1957                 return 0;
1958 
1959         if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid))
1960                 transfer_to[USRQUOTA] = dqget(sb, make_kqid_uid(iattr->ia_uid));
1961         if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))
1962                 transfer_to[GRPQUOTA] = dqget(sb, make_kqid_gid(iattr->ia_gid));
1963 
1964         ret = __dquot_transfer(inode, transfer_to);
1965         dqput_all(transfer_to);
1966         return ret;
1967 }
1968 EXPORT_SYMBOL(dquot_transfer);
1969 
1970 /*
1971  * Write info of quota file to disk
1972  */
1973 int dquot_commit_info(struct super_block *sb, int type)
1974 {
1975         int ret;
1976         struct quota_info *dqopt = sb_dqopt(sb);
1977 
1978         mutex_lock(&dqopt->dqio_mutex);
1979         ret = dqopt->ops[type]->write_file_info(sb, type);
1980         mutex_unlock(&dqopt->dqio_mutex);
1981         return ret;
1982 }
1983 EXPORT_SYMBOL(dquot_commit_info);
1984 
1985 /*
1986  * Definitions of diskquota operations.
1987  */
1988 const struct dquot_operations dquot_operations = {
1989         .write_dquot    = dquot_commit,
1990         .acquire_dquot  = dquot_acquire,
1991         .release_dquot  = dquot_release,
1992         .mark_dirty     = dquot_mark_dquot_dirty,
1993         .write_info     = dquot_commit_info,
1994         .alloc_dquot    = dquot_alloc,
1995         .destroy_dquot  = dquot_destroy,
1996 };
1997 EXPORT_SYMBOL(dquot_operations);
1998 
1999 /*
2000  * Generic helper for ->open on filesystems supporting disk quotas.
2001  */
2002 int dquot_file_open(struct inode *inode, struct file *file)
2003 {
2004         int error;
2005 
2006         error = generic_file_open(inode, file);
2007         if (!error && (file->f_mode & FMODE_WRITE))
2008                 dquot_initialize(inode);
2009         return error;
2010 }
2011 EXPORT_SYMBOL(dquot_file_open);
2012 
2013 /*
2014  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2015  */
2016 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2017 {
2018         int cnt, ret = 0;
2019         struct quota_info *dqopt = sb_dqopt(sb);
2020         struct inode *toputinode[MAXQUOTAS];
2021 
2022         /* Cannot turn off usage accounting without turning off limits, or
2023          * suspend quotas and simultaneously turn quotas off. */
2024         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2025             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2026             DQUOT_USAGE_ENABLED)))
2027                 return -EINVAL;
2028 
2029         /* We need to serialize quota_off() for device */
2030         mutex_lock(&dqopt->dqonoff_mutex);
2031 
2032         /*
2033          * Skip everything if there's nothing to do. We have to do this because
2034          * sometimes we are called when fill_super() failed and calling
2035          * sync_fs() in such cases does no good.
2036          */
2037         if (!sb_any_quota_loaded(sb)) {
2038                 mutex_unlock(&dqopt->dqonoff_mutex);
2039                 return 0;
2040         }
2041         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2042                 toputinode[cnt] = NULL;
2043                 if (type != -1 && cnt != type)
2044                         continue;
2045                 if (!sb_has_quota_loaded(sb, cnt))
2046                         continue;
2047 
2048                 if (flags & DQUOT_SUSPENDED) {
2049                         spin_lock(&dq_state_lock);
2050                         dqopt->flags |=
2051                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2052                         spin_unlock(&dq_state_lock);
2053                 } else {
2054                         spin_lock(&dq_state_lock);
2055                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2056                         /* Turning off suspended quotas? */
2057                         if (!sb_has_quota_loaded(sb, cnt) &&
2058                             sb_has_quota_suspended(sb, cnt)) {
2059                                 dqopt->flags &= ~dquot_state_flag(
2060                                                         DQUOT_SUSPENDED, cnt);
2061                                 spin_unlock(&dq_state_lock);
2062                                 iput(dqopt->files[cnt]);
2063                                 dqopt->files[cnt] = NULL;
2064                                 continue;
2065                         }
2066                         spin_unlock(&dq_state_lock);
2067                 }
2068 
2069                 /* We still have to keep quota loaded? */
2070                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2071                         continue;
2072 
2073                 /* Note: these are blocking operations */
2074                 drop_dquot_ref(sb, cnt);
2075                 invalidate_dquots(sb, cnt);
2076                 /*
2077                  * Now all dquots should be invalidated, all writes done so we
2078                  * should be only users of the info. No locks needed.
2079                  */
2080                 if (info_dirty(&dqopt->info[cnt]))
2081                         sb->dq_op->write_info(sb, cnt);
2082                 if (dqopt->ops[cnt]->free_file_info)
2083                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2084                 put_quota_format(dqopt->info[cnt].dqi_format);
2085 
2086                 toputinode[cnt] = dqopt->files[cnt];
2087                 if (!sb_has_quota_loaded(sb, cnt))
2088                         dqopt->files[cnt] = NULL;
2089                 dqopt->info[cnt].dqi_flags = 0;
2090                 dqopt->info[cnt].dqi_igrace = 0;
2091                 dqopt->info[cnt].dqi_bgrace = 0;
2092                 dqopt->ops[cnt] = NULL;
2093         }
2094         mutex_unlock(&dqopt->dqonoff_mutex);
2095 
2096         /* Skip syncing and setting flags if quota files are hidden */
2097         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2098                 goto put_inodes;
2099 
2100         /* Sync the superblock so that buffers with quota data are written to
2101          * disk (and so userspace sees correct data afterwards). */
2102         if (sb->s_op->sync_fs)
2103                 sb->s_op->sync_fs(sb, 1);
2104         sync_blockdev(sb->s_bdev);
2105         /* Now the quota files are just ordinary files and we can set the
2106          * inode flags back. Moreover we discard the pagecache so that
2107          * userspace sees the writes we did bypassing the pagecache. We
2108          * must also discard the blockdev buffers so that we see the
2109          * changes done by userspace on the next quotaon() */
2110         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2111                 if (toputinode[cnt]) {
2112                         mutex_lock(&dqopt->dqonoff_mutex);
2113                         /* If quota was reenabled in the meantime, we have
2114                          * nothing to do */
2115                         if (!sb_has_quota_loaded(sb, cnt)) {
2116                                 mutex_lock(&toputinode[cnt]->i_mutex);
2117                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
2118                                   S_NOATIME | S_NOQUOTA);
2119                                 truncate_inode_pages(&toputinode[cnt]->i_data,
2120                                                      0);
2121                                 mutex_unlock(&toputinode[cnt]->i_mutex);
2122                                 mark_inode_dirty_sync(toputinode[cnt]);
2123                         }
2124                         mutex_unlock(&dqopt->dqonoff_mutex);
2125                 }
2126         if (sb->s_bdev)
2127                 invalidate_bdev(sb->s_bdev);
2128 put_inodes:
2129         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2130                 if (toputinode[cnt]) {
2131                         /* On remount RO, we keep the inode pointer so that we
2132                          * can reenable quota on the subsequent remount RW. We
2133                          * have to check 'flags' variable and not use sb_has_
2134                          * function because another quotaon / quotaoff could
2135                          * change global state before we got here. We refuse
2136                          * to suspend quotas when there is pending delete on
2137                          * the quota file... */
2138                         if (!(flags & DQUOT_SUSPENDED))
2139                                 iput(toputinode[cnt]);
2140                         else if (!toputinode[cnt]->i_nlink)
2141                                 ret = -EBUSY;
2142                 }
2143         return ret;
2144 }
2145 EXPORT_SYMBOL(dquot_disable);
2146 
2147 int dquot_quota_off(struct super_block *sb, int type)
2148 {
2149         return dquot_disable(sb, type,
2150                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2151 }
2152 EXPORT_SYMBOL(dquot_quota_off);
2153 
2154 /*
2155  *      Turn quotas on on a device
2156  */
2157 
2158 /*
2159  * Helper function to turn quotas on when we already have the inode of
2160  * quota file and no quota information is loaded.
2161  */
2162 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
2163         unsigned int flags)
2164 {
2165         struct quota_format_type *fmt = find_quota_format(format_id);
2166         struct super_block *sb = inode->i_sb;
2167         struct quota_info *dqopt = sb_dqopt(sb);
2168         int error;
2169         int oldflags = -1;
2170 
2171         if (!fmt)
2172                 return -ESRCH;
2173         if (!S_ISREG(inode->i_mode)) {
2174                 error = -EACCES;
2175                 goto out_fmt;
2176         }
2177         if (IS_RDONLY(inode)) {
2178                 error = -EROFS;
2179                 goto out_fmt;
2180         }
2181         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
2182                 error = -EINVAL;
2183                 goto out_fmt;
2184         }
2185         /* Usage always has to be set... */
2186         if (!(flags & DQUOT_USAGE_ENABLED)) {
2187                 error = -EINVAL;
2188                 goto out_fmt;
2189         }
2190 
2191         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2192                 /* As we bypass the pagecache we must now flush all the
2193                  * dirty data and invalidate caches so that kernel sees
2194                  * changes from userspace. It is not enough to just flush
2195                  * the quota file since if blocksize < pagesize, invalidation
2196                  * of the cache could fail because of other unrelated dirty
2197                  * data */
2198                 sync_filesystem(sb);
2199                 invalidate_bdev(sb->s_bdev);
2200         }
2201         mutex_lock(&dqopt->dqonoff_mutex);
2202         if (sb_has_quota_loaded(sb, type)) {
2203                 error = -EBUSY;
2204                 goto out_lock;
2205         }
2206 
2207         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2208                 /* We don't want quota and atime on quota files (deadlocks
2209                  * possible) Also nobody should write to the file - we use
2210                  * special IO operations which ignore the immutable bit. */
2211                 mutex_lock(&inode->i_mutex);
2212                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
2213                                              S_NOQUOTA);
2214                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
2215                 mutex_unlock(&inode->i_mutex);
2216                 /*
2217                  * When S_NOQUOTA is set, remove dquot references as no more
2218                  * references can be added
2219                  */
2220                 __dquot_drop(inode);
2221         }
2222 
2223         error = -EIO;
2224         dqopt->files[type] = igrab(inode);
2225         if (!dqopt->files[type])
2226                 goto out_lock;
2227         error = -EINVAL;
2228         if (!fmt->qf_ops->check_quota_file(sb, type))
2229                 goto out_file_init;
2230 
2231         dqopt->ops[type] = fmt->qf_ops;
2232         dqopt->info[type].dqi_format = fmt;
2233         dqopt->info[type].dqi_fmt_id = format_id;
2234         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2235         mutex_lock(&dqopt->dqio_mutex);
2236         error = dqopt->ops[type]->read_file_info(sb, type);
2237         if (error < 0) {
2238                 mutex_unlock(&dqopt->dqio_mutex);
2239                 goto out_file_init;
2240         }
2241         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2242                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2243         mutex_unlock(&dqopt->dqio_mutex);
2244         spin_lock(&dq_state_lock);
2245         dqopt->flags |= dquot_state_flag(flags, type);
2246         spin_unlock(&dq_state_lock);
2247 
2248         add_dquot_ref(sb, type);
2249         mutex_unlock(&dqopt->dqonoff_mutex);
2250 
2251         return 0;
2252 
2253 out_file_init:
2254         dqopt->files[type] = NULL;
2255         iput(inode);
2256 out_lock:
2257         if (oldflags != -1) {
2258                 mutex_lock(&inode->i_mutex);
2259                 /* Set the flags back (in the case of accidental quotaon()
2260                  * on a wrong file we don't want to mess up the flags) */
2261                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
2262                 inode->i_flags |= oldflags;
2263                 mutex_unlock(&inode->i_mutex);
2264         }
2265         mutex_unlock(&dqopt->dqonoff_mutex);
2266 out_fmt:
2267         put_quota_format(fmt);
2268 
2269         return error; 
2270 }
2271 
2272 /* Reenable quotas on remount RW */
2273 int dquot_resume(struct super_block *sb, int type)
2274 {
2275         struct quota_info *dqopt = sb_dqopt(sb);
2276         struct inode *inode;
2277         int ret = 0, cnt;
2278         unsigned int flags;
2279 
2280         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2281                 if (type != -1 && cnt != type)
2282                         continue;
2283 
2284                 mutex_lock(&dqopt->dqonoff_mutex);
2285                 if (!sb_has_quota_suspended(sb, cnt)) {
2286                         mutex_unlock(&dqopt->dqonoff_mutex);
2287                         continue;
2288                 }
2289                 inode = dqopt->files[cnt];
2290                 dqopt->files[cnt] = NULL;
2291                 spin_lock(&dq_state_lock);
2292                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2293                                                         DQUOT_LIMITS_ENABLED,
2294                                                         cnt);
2295                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2296                 spin_unlock(&dq_state_lock);
2297                 mutex_unlock(&dqopt->dqonoff_mutex);
2298 
2299                 flags = dquot_generic_flag(flags, cnt);
2300                 ret = vfs_load_quota_inode(inode, cnt,
2301                                 dqopt->info[cnt].dqi_fmt_id, flags);
2302                 iput(inode);
2303         }
2304 
2305         return ret;
2306 }
2307 EXPORT_SYMBOL(dquot_resume);
2308 
2309 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2310                    struct path *path)
2311 {
2312         int error = security_quota_on(path->dentry);
2313         if (error)
2314                 return error;
2315         /* Quota file not on the same filesystem? */
2316         if (path->dentry->d_sb != sb)
2317                 error = -EXDEV;
2318         else
2319                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
2320                                              format_id, DQUOT_USAGE_ENABLED |
2321                                              DQUOT_LIMITS_ENABLED);
2322         return error;
2323 }
2324 EXPORT_SYMBOL(dquot_quota_on);
2325 
2326 /*
2327  * More powerful function for turning on quotas allowing setting
2328  * of individual quota flags
2329  */
2330 int dquot_enable(struct inode *inode, int type, int format_id,
2331                  unsigned int flags)
2332 {
2333         int ret = 0;
2334         struct super_block *sb = inode->i_sb;
2335         struct quota_info *dqopt = sb_dqopt(sb);
2336 
2337         /* Just unsuspend quotas? */
2338         BUG_ON(flags & DQUOT_SUSPENDED);
2339 
2340         if (!flags)
2341                 return 0;
2342         /* Just updating flags needed? */
2343         if (sb_has_quota_loaded(sb, type)) {
2344                 mutex_lock(&dqopt->dqonoff_mutex);
2345                 /* Now do a reliable test... */
2346                 if (!sb_has_quota_loaded(sb, type)) {
2347                         mutex_unlock(&dqopt->dqonoff_mutex);
2348                         goto load_quota;
2349                 }
2350                 if (flags & DQUOT_USAGE_ENABLED &&
2351                     sb_has_quota_usage_enabled(sb, type)) {
2352                         ret = -EBUSY;
2353                         goto out_lock;
2354                 }
2355                 if (flags & DQUOT_LIMITS_ENABLED &&
2356                     sb_has_quota_limits_enabled(sb, type)) {
2357                         ret = -EBUSY;
2358                         goto out_lock;
2359                 }
2360                 spin_lock(&dq_state_lock);
2361                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2362                 spin_unlock(&dq_state_lock);
2363 out_lock:
2364                 mutex_unlock(&dqopt->dqonoff_mutex);
2365                 return ret;
2366         }
2367 
2368 load_quota:
2369         return vfs_load_quota_inode(inode, type, format_id, flags);
2370 }
2371 EXPORT_SYMBOL(dquot_enable);
2372 
2373 /*
2374  * This function is used when filesystem needs to initialize quotas
2375  * during mount time.
2376  */
2377 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2378                 int format_id, int type)
2379 {
2380         struct dentry *dentry;
2381         int error;
2382 
2383         mutex_lock(&sb->s_root->d_inode->i_mutex);
2384         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2385         mutex_unlock(&sb->s_root->d_inode->i_mutex);
2386         if (IS_ERR(dentry))
2387                 return PTR_ERR(dentry);
2388 
2389         if (!dentry->d_inode) {
2390                 error = -ENOENT;
2391                 goto out;
2392         }
2393 
2394         error = security_quota_on(dentry);
2395         if (!error)
2396                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2397                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2398 
2399 out:
2400         dput(dentry);
2401         return error;
2402 }
2403 EXPORT_SYMBOL(dquot_quota_on_mount);
2404 
2405 static inline qsize_t qbtos(qsize_t blocks)
2406 {
2407         return blocks << QIF_DQBLKSIZE_BITS;
2408 }
2409 
2410 static inline qsize_t stoqb(qsize_t space)
2411 {
2412         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2413 }
2414 
2415 /* Generic routine for getting common part of quota structure */
2416 static void do_get_dqblk(struct dquot *dquot, struct fs_disk_quota *di)
2417 {
2418         struct mem_dqblk *dm = &dquot->dq_dqb;
2419 
2420         memset(di, 0, sizeof(*di));
2421         di->d_version = FS_DQUOT_VERSION;
2422         di->d_flags = dquot->dq_id.type == USRQUOTA ?
2423                         FS_USER_QUOTA : FS_GROUP_QUOTA;
2424         di->d_id = from_kqid_munged(current_user_ns(), dquot->dq_id);
2425 
2426         spin_lock(&dq_data_lock);
2427         di->d_blk_hardlimit = stoqb(dm->dqb_bhardlimit);
2428         di->d_blk_softlimit = stoqb(dm->dqb_bsoftlimit);
2429         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2430         di->d_ino_softlimit = dm->dqb_isoftlimit;
2431         di->d_bcount = dm->dqb_curspace + dm->dqb_rsvspace;
2432         di->d_icount = dm->dqb_curinodes;
2433         di->d_btimer = dm->dqb_btime;
2434         di->d_itimer = dm->dqb_itime;
2435         spin_unlock(&dq_data_lock);
2436 }
2437 
2438 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2439                     struct fs_disk_quota *di)
2440 {
2441         struct dquot *dquot;
2442 
2443         dquot = dqget(sb, qid);
2444         if (!dquot)
2445                 return -ESRCH;
2446         do_get_dqblk(dquot, di);
2447         dqput(dquot);
2448 
2449         return 0;
2450 }
2451 EXPORT_SYMBOL(dquot_get_dqblk);
2452 
2453 #define VFS_FS_DQ_MASK \
2454         (FS_DQ_BCOUNT | FS_DQ_BSOFT | FS_DQ_BHARD | \
2455          FS_DQ_ICOUNT | FS_DQ_ISOFT | FS_DQ_IHARD | \
2456          FS_DQ_BTIMER | FS_DQ_ITIMER)
2457 
2458 /* Generic routine for setting common part of quota structure */
2459 static int do_set_dqblk(struct dquot *dquot, struct fs_disk_quota *di)
2460 {
2461         struct mem_dqblk *dm = &dquot->dq_dqb;
2462         int check_blim = 0, check_ilim = 0;
2463         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2464 
2465         if (di->d_fieldmask & ~VFS_FS_DQ_MASK)
2466                 return -EINVAL;
2467 
2468         if (((di->d_fieldmask & FS_DQ_BSOFT) &&
2469              (di->d_blk_softlimit > dqi->dqi_maxblimit)) ||
2470             ((di->d_fieldmask & FS_DQ_BHARD) &&
2471              (di->d_blk_hardlimit > dqi->dqi_maxblimit)) ||
2472             ((di->d_fieldmask & FS_DQ_ISOFT) &&
2473              (di->d_ino_softlimit > dqi->dqi_maxilimit)) ||
2474             ((di->d_fieldmask & FS_DQ_IHARD) &&
2475              (di->d_ino_hardlimit > dqi->dqi_maxilimit)))
2476                 return -ERANGE;
2477 
2478         spin_lock(&dq_data_lock);
2479         if (di->d_fieldmask & FS_DQ_BCOUNT) {
2480                 dm->dqb_curspace = di->d_bcount - dm->dqb_rsvspace;
2481                 check_blim = 1;
2482                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2483         }
2484 
2485         if (di->d_fieldmask & FS_DQ_BSOFT)
2486                 dm->dqb_bsoftlimit = qbtos(di->d_blk_softlimit);
2487         if (di->d_fieldmask & FS_DQ_BHARD)
2488                 dm->dqb_bhardlimit = qbtos(di->d_blk_hardlimit);
2489         if (di->d_fieldmask & (FS_DQ_BSOFT | FS_DQ_BHARD)) {
2490                 check_blim = 1;
2491                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2492         }
2493 
2494         if (di->d_fieldmask & FS_DQ_ICOUNT) {
2495                 dm->dqb_curinodes = di->d_icount;
2496                 check_ilim = 1;
2497                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2498         }
2499 
2500         if (di->d_fieldmask & FS_DQ_ISOFT)
2501                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2502         if (di->d_fieldmask & FS_DQ_IHARD)
2503                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2504         if (di->d_fieldmask & (FS_DQ_ISOFT | FS_DQ_IHARD)) {
2505                 check_ilim = 1;
2506                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2507         }
2508 
2509         if (di->d_fieldmask & FS_DQ_BTIMER) {
2510                 dm->dqb_btime = di->d_btimer;
2511                 check_blim = 1;
2512                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2513         }
2514 
2515         if (di->d_fieldmask & FS_DQ_ITIMER) {
2516                 dm->dqb_itime = di->d_itimer;
2517                 check_ilim = 1;
2518                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2519         }
2520 
2521         if (check_blim) {
2522                 if (!dm->dqb_bsoftlimit ||
2523                     dm->dqb_curspace < dm->dqb_bsoftlimit) {
2524                         dm->dqb_btime = 0;
2525                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2526                 } else if (!(di->d_fieldmask & FS_DQ_BTIMER))
2527                         /* Set grace only if user hasn't provided his own... */
2528                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2529         }
2530         if (check_ilim) {
2531                 if (!dm->dqb_isoftlimit ||
2532                     dm->dqb_curinodes < dm->dqb_isoftlimit) {
2533                         dm->dqb_itime = 0;
2534                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2535                 } else if (!(di->d_fieldmask & FS_DQ_ITIMER))
2536                         /* Set grace only if user hasn't provided his own... */
2537                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2538         }
2539         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2540             dm->dqb_isoftlimit)
2541                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2542         else
2543                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2544         spin_unlock(&dq_data_lock);
2545         mark_dquot_dirty(dquot);
2546 
2547         return 0;
2548 }
2549 
2550 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2551                   struct fs_disk_quota *di)
2552 {
2553         struct dquot *dquot;
2554         int rc;
2555 
2556         dquot = dqget(sb, qid);
2557         if (!dquot) {
2558                 rc = -ESRCH;
2559                 goto out;
2560         }
2561         rc = do_set_dqblk(dquot, di);
2562         dqput(dquot);
2563 out:
2564         return rc;
2565 }
2566 EXPORT_SYMBOL(dquot_set_dqblk);
2567 
2568 /* Generic routine for getting common part of quota file information */
2569 int dquot_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2570 {
2571         struct mem_dqinfo *mi;
2572   
2573         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2574         if (!sb_has_quota_active(sb, type)) {
2575                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2576                 return -ESRCH;
2577         }
2578         mi = sb_dqopt(sb)->info + type;
2579         spin_lock(&dq_data_lock);
2580         ii->dqi_bgrace = mi->dqi_bgrace;
2581         ii->dqi_igrace = mi->dqi_igrace;
2582         ii->dqi_flags = mi->dqi_flags & DQF_GETINFO_MASK;
2583         ii->dqi_valid = IIF_ALL;
2584         spin_unlock(&dq_data_lock);
2585         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2586         return 0;
2587 }
2588 EXPORT_SYMBOL(dquot_get_dqinfo);
2589 
2590 /* Generic routine for setting common part of quota file information */
2591 int dquot_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2592 {
2593         struct mem_dqinfo *mi;
2594         int err = 0;
2595 
2596         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2597         if (!sb_has_quota_active(sb, type)) {
2598                 err = -ESRCH;
2599                 goto out;
2600         }
2601         mi = sb_dqopt(sb)->info + type;
2602         spin_lock(&dq_data_lock);
2603         if (ii->dqi_valid & IIF_BGRACE)
2604                 mi->dqi_bgrace = ii->dqi_bgrace;
2605         if (ii->dqi_valid & IIF_IGRACE)
2606                 mi->dqi_igrace = ii->dqi_igrace;
2607         if (ii->dqi_valid & IIF_FLAGS)
2608                 mi->dqi_flags = (mi->dqi_flags & ~DQF_SETINFO_MASK) |
2609                                 (ii->dqi_flags & DQF_SETINFO_MASK);
2610         spin_unlock(&dq_data_lock);
2611         mark_info_dirty(sb, type);
2612         /* Force write to disk */
2613         sb->dq_op->write_info(sb, type);
2614 out:
2615         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2616         return err;
2617 }
2618 EXPORT_SYMBOL(dquot_set_dqinfo);
2619 
2620 const struct quotactl_ops dquot_quotactl_ops = {
2621         .quota_on       = dquot_quota_on,
2622         .quota_off      = dquot_quota_off,
2623         .quota_sync     = dquot_quota_sync,
2624         .get_info       = dquot_get_dqinfo,
2625         .set_info       = dquot_set_dqinfo,
2626         .get_dqblk      = dquot_get_dqblk,
2627         .set_dqblk      = dquot_set_dqblk
2628 };
2629 EXPORT_SYMBOL(dquot_quotactl_ops);
2630 
2631 static int do_proc_dqstats(struct ctl_table *table, int write,
2632                      void __user *buffer, size_t *lenp, loff_t *ppos)
2633 {
2634         unsigned int type = (int *)table->data - dqstats.stat;
2635 
2636         /* Update global table */
2637         dqstats.stat[type] =
2638                         percpu_counter_sum_positive(&dqstats.counter[type]);
2639         return proc_dointvec(table, write, buffer, lenp, ppos);
2640 }
2641 
2642 static ctl_table fs_dqstats_table[] = {
2643         {
2644                 .procname       = "lookups",
2645                 .data           = &dqstats.stat[DQST_LOOKUPS],
2646                 .maxlen         = sizeof(int),
2647                 .mode           = 0444,
2648                 .proc_handler   = do_proc_dqstats,
2649         },
2650         {
2651                 .procname       = "drops",
2652                 .data           = &dqstats.stat[DQST_DROPS],
2653                 .maxlen         = sizeof(int),
2654                 .mode           = 0444,
2655                 .proc_handler   = do_proc_dqstats,
2656         },
2657         {
2658                 .procname       = "reads",
2659                 .data           = &dqstats.stat[DQST_READS],
2660                 .maxlen         = sizeof(int),
2661                 .mode           = 0444,
2662                 .proc_handler   = do_proc_dqstats,
2663         },
2664         {
2665                 .procname       = "writes",
2666                 .data           = &dqstats.stat[DQST_WRITES],
2667                 .maxlen         = sizeof(int),
2668                 .mode           = 0444,
2669                 .proc_handler   = do_proc_dqstats,
2670         },
2671         {
2672                 .procname       = "cache_hits",
2673                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2674                 .maxlen         = sizeof(int),
2675                 .mode           = 0444,
2676                 .proc_handler   = do_proc_dqstats,
2677         },
2678         {
2679                 .procname       = "allocated_dquots",
2680                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2681                 .maxlen         = sizeof(int),
2682                 .mode           = 0444,
2683                 .proc_handler   = do_proc_dqstats,
2684         },
2685         {
2686                 .procname       = "free_dquots",
2687                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2688                 .maxlen         = sizeof(int),
2689                 .mode           = 0444,
2690                 .proc_handler   = do_proc_dqstats,
2691         },
2692         {
2693                 .procname       = "syncs",
2694                 .data           = &dqstats.stat[DQST_SYNCS],
2695                 .maxlen         = sizeof(int),
2696                 .mode           = 0444,
2697                 .proc_handler   = do_proc_dqstats,
2698         },
2699 #ifdef CONFIG_PRINT_QUOTA_WARNING
2700         {
2701                 .procname       = "warnings",
2702                 .data           = &flag_print_warnings,
2703                 .maxlen         = sizeof(int),
2704                 .mode           = 0644,
2705                 .proc_handler   = proc_dointvec,
2706         },
2707 #endif
2708         { },
2709 };
2710 
2711 static ctl_table fs_table[] = {
2712         {
2713                 .procname       = "quota",
2714                 .mode           = 0555,
2715                 .child          = fs_dqstats_table,
2716         },
2717         { },
2718 };
2719 
2720 static ctl_table sys_table[] = {
2721         {
2722                 .procname       = "fs",
2723                 .mode           = 0555,
2724                 .child          = fs_table,
2725         },
2726         { },
2727 };
2728 
2729 static int __init dquot_init(void)
2730 {
2731         int i, ret;
2732         unsigned long nr_hash, order;
2733 
2734         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2735 
2736         register_sysctl_table(sys_table);
2737 
2738         dquot_cachep = kmem_cache_create("dquot",
2739                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2740                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2741                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2742                         NULL);
2743 
2744         order = 0;
2745         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2746         if (!dquot_hash)
2747                 panic("Cannot create dquot hash table");
2748 
2749         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2750                 ret = percpu_counter_init(&dqstats.counter[i], 0);
2751                 if (ret)
2752                         panic("Cannot create dquot stat counters");
2753         }
2754 
2755         /* Find power-of-two hlist_heads which can fit into allocation */
2756         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2757         dq_hash_bits = 0;
2758         do {
2759                 dq_hash_bits++;
2760         } while (nr_hash >> dq_hash_bits);
2761         dq_hash_bits--;
2762 
2763         nr_hash = 1UL << dq_hash_bits;
2764         dq_hash_mask = nr_hash - 1;
2765         for (i = 0; i < nr_hash; i++)
2766                 INIT_HLIST_HEAD(dquot_hash + i);
2767 
2768         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2769                         nr_hash, order, (PAGE_SIZE << order));
2770 
2771         register_shrinker(&dqcache_shrinker);
2772 
2773         return 0;
2774 }
2775 module_init(dquot_init);
2776 

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