~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

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

Version: ~ [ linux-5.13-rc5 ] ~ [ linux-5.12.9 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.42 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.124 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.193 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.235 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.271 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.271 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Implementation of the diskquota system for the LINUX operating system. QUOTA
  4  * is implemented using the BSD system call interface as the means of
  5  * communication with the user level. This file contains the generic routines
  6  * called by the different filesystems on allocation of an inode or block.
  7  * These routines take care of the administration needed to have a consistent
  8  * diskquota tracking system. The ideas of both user and group quotas are based
  9  * on the Melbourne quota system as used on BSD derived systems. The internal
 10  * implementation is based on one of the several variants of the LINUX
 11  * inode-subsystem with added complexity of the diskquota system.
 12  *
 13  * Author:      Marco van Wieringen <mvw@planets.elm.net>
 14  *
 15  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
 16  *
 17  *              Revised list management to avoid races
 18  *              -- Bill Hawes, <whawes@star.net>, 9/98
 19  *
 20  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
 21  *              As the consequence the locking was moved from dquot_decr_...(),
 22  *              dquot_incr_...() to calling functions.
 23  *              invalidate_dquots() now writes modified dquots.
 24  *              Serialized quota_off() and quota_on() for mount point.
 25  *              Fixed a few bugs in grow_dquots().
 26  *              Fixed deadlock in write_dquot() - we no longer account quotas on
 27  *              quota files
 28  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
 29  *              add_dquot_ref() restarts after blocking
 30  *              Added check for bogus uid and fixed check for group in quotactl.
 31  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
 32  *
 33  *              Used struct list_head instead of own list struct
 34  *              Invalidation of referenced dquots is no longer possible
 35  *              Improved free_dquots list management
 36  *              Quota and i_blocks are now updated in one place to avoid races
 37  *              Warnings are now delayed so we won't block in critical section
 38  *              Write updated not to require dquot lock
 39  *              Jan Kara, <jack@suse.cz>, 9/2000
 40  *
 41  *              Added dynamic quota structure allocation
 42  *              Jan Kara <jack@suse.cz> 12/2000
 43  *
 44  *              Rewritten quota interface. Implemented new quota format and
 45  *              formats registering.
 46  *              Jan Kara, <jack@suse.cz>, 2001,2002
 47  *
 48  *              New SMP locking.
 49  *              Jan Kara, <jack@suse.cz>, 10/2002
 50  *
 51  *              Added journalled quota support, fix lock inversion problems
 52  *              Jan Kara, <jack@suse.cz>, 2003,2004
 53  *
 54  * (C) Copyright 1994 - 1997 Marco van Wieringen
 55  */
 56 
 57 #include <linux/errno.h>
 58 #include <linux/kernel.h>
 59 #include <linux/fs.h>
 60 #include <linux/mount.h>
 61 #include <linux/mm.h>
 62 #include <linux/time.h>
 63 #include <linux/types.h>
 64 #include <linux/string.h>
 65 #include <linux/fcntl.h>
 66 #include <linux/stat.h>
 67 #include <linux/tty.h>
 68 #include <linux/file.h>
 69 #include <linux/slab.h>
 70 #include <linux/sysctl.h>
 71 #include <linux/init.h>
 72 #include <linux/module.h>
 73 #include <linux/proc_fs.h>
 74 #include <linux/security.h>
 75 #include <linux/sched.h>
 76 #include <linux/cred.h>
 77 #include <linux/kmod.h>
 78 #include <linux/namei.h>
 79 #include <linux/capability.h>
 80 #include <linux/quotaops.h>
 81 #include "../internal.h" /* ugh */
 82 
 83 #include <linux/uaccess.h>
 84 
 85 /*
 86  * There are five quota SMP locks:
 87  * * dq_list_lock protects all lists with quotas and quota formats.
 88  * * dquot->dq_dqb_lock protects data from dq_dqb
 89  * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
 90  *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
 91  *   dquot_transfer() can stabilize amount it transfers
 92  * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
 93  *   pointers in the inode
 94  * * dq_state_lock protects modifications of quota state (on quotaon and
 95  *   quotaoff) and readers who care about latest values take it as well.
 96  *
 97  * The spinlock ordering is hence:
 98  *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
 99  *   dq_list_lock > dq_state_lock
100  *
101  * Note that some things (eg. sb pointer, type, id) doesn't change during
102  * the life of the dquot structure and so needn't to be protected by a lock
103  *
104  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
105  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
106  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
107  * inode and before dropping dquot references to avoid use of dquots after
108  * they are freed. dq_data_lock is used to serialize the pointer setting and
109  * clearing operations.
110  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
111  * inode is a quota file). Functions adding pointers from inode to dquots have
112  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
113  * have to do all pointer modifications before dropping dq_data_lock. This makes
114  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
115  * then drops all pointers to dquots from an inode.
116  *
117  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
118  * memory (or space for it is being allocated) on the first dqget(), when it is
119  * being written out, and when it is being released on the last dqput(). The
120  * allocation and release operations are serialized by the dq_lock and by
121  * checking the use count in dquot_release().
122  *
123  * Lock ordering (including related VFS locks) is the following:
124  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
125  */
126 
127 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
129 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
130 EXPORT_SYMBOL(dq_data_lock);
131 DEFINE_STATIC_SRCU(dquot_srcu);
132 
133 static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
134 
135 void __quota_error(struct super_block *sb, const char *func,
136                    const char *fmt, ...)
137 {
138         if (printk_ratelimit()) {
139                 va_list args;
140                 struct va_format vaf;
141 
142                 va_start(args, fmt);
143 
144                 vaf.fmt = fmt;
145                 vaf.va = &args;
146 
147                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
148                        sb->s_id, func, &vaf);
149 
150                 va_end(args);
151         }
152 }
153 EXPORT_SYMBOL(__quota_error);
154 
155 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
156 static char *quotatypes[] = INITQFNAMES;
157 #endif
158 static struct quota_format_type *quota_formats; /* List of registered formats */
159 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
160 
161 /* SLAB cache for dquot structures */
162 static struct kmem_cache *dquot_cachep;
163 
164 int register_quota_format(struct quota_format_type *fmt)
165 {
166         spin_lock(&dq_list_lock);
167         fmt->qf_next = quota_formats;
168         quota_formats = fmt;
169         spin_unlock(&dq_list_lock);
170         return 0;
171 }
172 EXPORT_SYMBOL(register_quota_format);
173 
174 void unregister_quota_format(struct quota_format_type *fmt)
175 {
176         struct quota_format_type **actqf;
177 
178         spin_lock(&dq_list_lock);
179         for (actqf = &quota_formats; *actqf && *actqf != fmt;
180              actqf = &(*actqf)->qf_next)
181                 ;
182         if (*actqf)
183                 *actqf = (*actqf)->qf_next;
184         spin_unlock(&dq_list_lock);
185 }
186 EXPORT_SYMBOL(unregister_quota_format);
187 
188 static struct quota_format_type *find_quota_format(int id)
189 {
190         struct quota_format_type *actqf;
191 
192         spin_lock(&dq_list_lock);
193         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
194              actqf = actqf->qf_next)
195                 ;
196         if (!actqf || !try_module_get(actqf->qf_owner)) {
197                 int qm;
198 
199                 spin_unlock(&dq_list_lock);
200 
201                 for (qm = 0; module_names[qm].qm_fmt_id &&
202                              module_names[qm].qm_fmt_id != id; qm++)
203                         ;
204                 if (!module_names[qm].qm_fmt_id ||
205                     request_module(module_names[qm].qm_mod_name))
206                         return NULL;
207 
208                 spin_lock(&dq_list_lock);
209                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
210                      actqf = actqf->qf_next)
211                         ;
212                 if (actqf && !try_module_get(actqf->qf_owner))
213                         actqf = NULL;
214         }
215         spin_unlock(&dq_list_lock);
216         return actqf;
217 }
218 
219 static void put_quota_format(struct quota_format_type *fmt)
220 {
221         module_put(fmt->qf_owner);
222 }
223 
224 /*
225  * Dquot List Management:
226  * The quota code uses four lists for dquot management: the inuse_list,
227  * free_dquots, dqi_dirty_list, and dquot_hash[] array. A single dquot
228  * structure may be on some of those lists, depending on its current state.
229  *
230  * All dquots are placed to the end of inuse_list when first created, and this
231  * list is used for invalidate operation, which must look at every dquot.
232  *
233  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
234  * and this list is searched whenever we need an available dquot.  Dquots are
235  * removed from the list as soon as they are used again, and
236  * dqstats.free_dquots gives the number of dquots on the list. When
237  * dquot is invalidated it's completely released from memory.
238  *
239  * Dirty dquots are added to the dqi_dirty_list of quota_info when mark
240  * dirtied, and this list is searched when writing dirty dquots back to
241  * quota file. Note that some filesystems do dirty dquot tracking on their
242  * own (e.g. in a journal) and thus don't use dqi_dirty_list.
243  *
244  * Dquots with a specific identity (device, type and id) are placed on
245  * one of the dquot_hash[] hash chains. The provides an efficient search
246  * mechanism to locate a specific dquot.
247  */
248 
249 static LIST_HEAD(inuse_list);
250 static LIST_HEAD(free_dquots);
251 static unsigned int dq_hash_bits, dq_hash_mask;
252 static struct hlist_head *dquot_hash;
253 
254 struct dqstats dqstats;
255 EXPORT_SYMBOL(dqstats);
256 
257 static qsize_t inode_get_rsv_space(struct inode *inode);
258 static qsize_t __inode_get_rsv_space(struct inode *inode);
259 static int __dquot_initialize(struct inode *inode, int type);
260 
261 static inline unsigned int
262 hashfn(const struct super_block *sb, struct kqid qid)
263 {
264         unsigned int id = from_kqid(&init_user_ns, qid);
265         int type = qid.type;
266         unsigned long tmp;
267 
268         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
269         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
270 }
271 
272 /*
273  * Following list functions expect dq_list_lock to be held
274  */
275 static inline void insert_dquot_hash(struct dquot *dquot)
276 {
277         struct hlist_head *head;
278         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
279         hlist_add_head(&dquot->dq_hash, head);
280 }
281 
282 static inline void remove_dquot_hash(struct dquot *dquot)
283 {
284         hlist_del_init(&dquot->dq_hash);
285 }
286 
287 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
288                                 struct kqid qid)
289 {
290         struct hlist_node *node;
291         struct dquot *dquot;
292 
293         hlist_for_each (node, dquot_hash+hashent) {
294                 dquot = hlist_entry(node, struct dquot, dq_hash);
295                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
296                         return dquot;
297         }
298         return NULL;
299 }
300 
301 /* Add a dquot to the tail of the free list */
302 static inline void put_dquot_last(struct dquot *dquot)
303 {
304         list_add_tail(&dquot->dq_free, &free_dquots);
305         dqstats_inc(DQST_FREE_DQUOTS);
306 }
307 
308 static inline void remove_free_dquot(struct dquot *dquot)
309 {
310         if (list_empty(&dquot->dq_free))
311                 return;
312         list_del_init(&dquot->dq_free);
313         dqstats_dec(DQST_FREE_DQUOTS);
314 }
315 
316 static inline void put_inuse(struct dquot *dquot)
317 {
318         /* We add to the back of inuse list so we don't have to restart
319          * when traversing this list and we block */
320         list_add_tail(&dquot->dq_inuse, &inuse_list);
321         dqstats_inc(DQST_ALLOC_DQUOTS);
322 }
323 
324 static inline void remove_inuse(struct dquot *dquot)
325 {
326         dqstats_dec(DQST_ALLOC_DQUOTS);
327         list_del(&dquot->dq_inuse);
328 }
329 /*
330  * End of list functions needing dq_list_lock
331  */
332 
333 static void wait_on_dquot(struct dquot *dquot)
334 {
335         mutex_lock(&dquot->dq_lock);
336         mutex_unlock(&dquot->dq_lock);
337 }
338 
339 static inline int dquot_dirty(struct dquot *dquot)
340 {
341         return test_bit(DQ_MOD_B, &dquot->dq_flags);
342 }
343 
344 static inline int mark_dquot_dirty(struct dquot *dquot)
345 {
346         return dquot->dq_sb->dq_op->mark_dirty(dquot);
347 }
348 
349 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
350 int dquot_mark_dquot_dirty(struct dquot *dquot)
351 {
352         int ret = 1;
353 
354         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
355                 return 0;
356 
357         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
358                 return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
359 
360         /* If quota is dirty already, we don't have to acquire dq_list_lock */
361         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
362                 return 1;
363 
364         spin_lock(&dq_list_lock);
365         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
366                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
367                                 info[dquot->dq_id.type].dqi_dirty_list);
368                 ret = 0;
369         }
370         spin_unlock(&dq_list_lock);
371         return ret;
372 }
373 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
374 
375 /* Dirtify all the dquots - this can block when journalling */
376 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
377 {
378         int ret, err, cnt;
379 
380         ret = err = 0;
381         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
382                 if (dquot[cnt])
383                         /* Even in case of error we have to continue */
384                         ret = mark_dquot_dirty(dquot[cnt]);
385                 if (!err)
386                         err = ret;
387         }
388         return err;
389 }
390 
391 static inline void dqput_all(struct dquot **dquot)
392 {
393         unsigned int cnt;
394 
395         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
396                 dqput(dquot[cnt]);
397 }
398 
399 static inline int clear_dquot_dirty(struct dquot *dquot)
400 {
401         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
402                 return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
403 
404         spin_lock(&dq_list_lock);
405         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
406                 spin_unlock(&dq_list_lock);
407                 return 0;
408         }
409         list_del_init(&dquot->dq_dirty);
410         spin_unlock(&dq_list_lock);
411         return 1;
412 }
413 
414 void mark_info_dirty(struct super_block *sb, int type)
415 {
416         spin_lock(&dq_data_lock);
417         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
418         spin_unlock(&dq_data_lock);
419 }
420 EXPORT_SYMBOL(mark_info_dirty);
421 
422 /*
423  *      Read dquot from disk and alloc space for it
424  */
425 
426 int dquot_acquire(struct dquot *dquot)
427 {
428         int ret = 0, ret2 = 0;
429         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
430 
431         mutex_lock(&dquot->dq_lock);
432         if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
433                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
434                 if (ret < 0)
435                         goto out_iolock;
436         }
437         /* Make sure flags update is visible after dquot has been filled */
438         smp_mb__before_atomic();
439         set_bit(DQ_READ_B, &dquot->dq_flags);
440         /* Instantiate dquot if needed */
441         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
442                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
443                 /* Write the info if needed */
444                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
445                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
446                                         dquot->dq_sb, dquot->dq_id.type);
447                 }
448                 if (ret < 0)
449                         goto out_iolock;
450                 if (ret2 < 0) {
451                         ret = ret2;
452                         goto out_iolock;
453                 }
454         }
455         /*
456          * Make sure flags update is visible after on-disk struct has been
457          * allocated. Paired with smp_rmb() in dqget().
458          */
459         smp_mb__before_atomic();
460         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
461 out_iolock:
462         mutex_unlock(&dquot->dq_lock);
463         return ret;
464 }
465 EXPORT_SYMBOL(dquot_acquire);
466 
467 /*
468  *      Write dquot to disk
469  */
470 int dquot_commit(struct dquot *dquot)
471 {
472         int ret = 0;
473         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
474 
475         mutex_lock(&dquot->dq_lock);
476         if (!clear_dquot_dirty(dquot))
477                 goto out_lock;
478         /* Inactive dquot can be only if there was error during read/init
479          * => we have better not writing it */
480         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
481                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
482         else
483                 ret = -EIO;
484 out_lock:
485         mutex_unlock(&dquot->dq_lock);
486         return ret;
487 }
488 EXPORT_SYMBOL(dquot_commit);
489 
490 /*
491  *      Release dquot
492  */
493 int dquot_release(struct dquot *dquot)
494 {
495         int ret = 0, ret2 = 0;
496         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
497 
498         mutex_lock(&dquot->dq_lock);
499         /* Check whether we are not racing with some other dqget() */
500         if (dquot_is_busy(dquot))
501                 goto out_dqlock;
502         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
503                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
504                 /* Write the info */
505                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
506                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
507                                                 dquot->dq_sb, dquot->dq_id.type);
508                 }
509                 if (ret >= 0)
510                         ret = ret2;
511         }
512         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
513 out_dqlock:
514         mutex_unlock(&dquot->dq_lock);
515         return ret;
516 }
517 EXPORT_SYMBOL(dquot_release);
518 
519 void dquot_destroy(struct dquot *dquot)
520 {
521         kmem_cache_free(dquot_cachep, dquot);
522 }
523 EXPORT_SYMBOL(dquot_destroy);
524 
525 static inline void do_destroy_dquot(struct dquot *dquot)
526 {
527         dquot->dq_sb->dq_op->destroy_dquot(dquot);
528 }
529 
530 /* Invalidate all dquots on the list. Note that this function is called after
531  * quota is disabled and pointers from inodes removed so there cannot be new
532  * quota users. There can still be some users of quotas due to inodes being
533  * just deleted or pruned by prune_icache() (those are not attached to any
534  * list) or parallel quotactl call. We have to wait for such users.
535  */
536 static void invalidate_dquots(struct super_block *sb, int type)
537 {
538         struct dquot *dquot, *tmp;
539 
540 restart:
541         spin_lock(&dq_list_lock);
542         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
543                 if (dquot->dq_sb != sb)
544                         continue;
545                 if (dquot->dq_id.type != type)
546                         continue;
547                 /* Wait for dquot users */
548                 if (atomic_read(&dquot->dq_count)) {
549                         dqgrab(dquot);
550                         spin_unlock(&dq_list_lock);
551                         /*
552                          * Once dqput() wakes us up, we know it's time to free
553                          * the dquot.
554                          * IMPORTANT: we rely on the fact that there is always
555                          * at most one process waiting for dquot to free.
556                          * Otherwise dq_count would be > 1 and we would never
557                          * wake up.
558                          */
559                         wait_event(dquot_ref_wq,
560                                    atomic_read(&dquot->dq_count) == 1);
561                         dqput(dquot);
562                         /* At this moment dquot() need not exist (it could be
563                          * reclaimed by prune_dqcache(). Hence we must
564                          * restart. */
565                         goto restart;
566                 }
567                 /*
568                  * Quota now has no users and it has been written on last
569                  * dqput()
570                  */
571                 remove_dquot_hash(dquot);
572                 remove_free_dquot(dquot);
573                 remove_inuse(dquot);
574                 do_destroy_dquot(dquot);
575         }
576         spin_unlock(&dq_list_lock);
577 }
578 
579 /* Call callback for every active dquot on given filesystem */
580 int dquot_scan_active(struct super_block *sb,
581                       int (*fn)(struct dquot *dquot, unsigned long priv),
582                       unsigned long priv)
583 {
584         struct dquot *dquot, *old_dquot = NULL;
585         int ret = 0;
586 
587         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
588 
589         spin_lock(&dq_list_lock);
590         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
591                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
592                         continue;
593                 if (dquot->dq_sb != sb)
594                         continue;
595                 /* Now we have active dquot so we can just increase use count */
596                 atomic_inc(&dquot->dq_count);
597                 spin_unlock(&dq_list_lock);
598                 dqput(old_dquot);
599                 old_dquot = dquot;
600                 /*
601                  * ->release_dquot() can be racing with us. Our reference
602                  * protects us from new calls to it so just wait for any
603                  * outstanding call and recheck the DQ_ACTIVE_B after that.
604                  */
605                 wait_on_dquot(dquot);
606                 if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
607                         ret = fn(dquot, priv);
608                         if (ret < 0)
609                                 goto out;
610                 }
611                 spin_lock(&dq_list_lock);
612                 /* We are safe to continue now because our dquot could not
613                  * be moved out of the inuse list while we hold the reference */
614         }
615         spin_unlock(&dq_list_lock);
616 out:
617         dqput(old_dquot);
618         return ret;
619 }
620 EXPORT_SYMBOL(dquot_scan_active);
621 
622 /* Write all dquot structures to quota files */
623 int dquot_writeback_dquots(struct super_block *sb, int type)
624 {
625         struct list_head dirty;
626         struct dquot *dquot;
627         struct quota_info *dqopt = sb_dqopt(sb);
628         int cnt;
629         int err, ret = 0;
630 
631         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
632 
633         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
634                 if (type != -1 && cnt != type)
635                         continue;
636                 if (!sb_has_quota_active(sb, cnt))
637                         continue;
638                 spin_lock(&dq_list_lock);
639                 /* Move list away to avoid livelock. */
640                 list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty);
641                 while (!list_empty(&dirty)) {
642                         dquot = list_first_entry(&dirty, struct dquot,
643                                                  dq_dirty);
644 
645                         WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
646 
647                         /* Now we have active dquot from which someone is
648                          * holding reference so we can safely just increase
649                          * use count */
650                         dqgrab(dquot);
651                         spin_unlock(&dq_list_lock);
652                         err = sb->dq_op->write_dquot(dquot);
653                         if (err) {
654                                 /*
655                                  * Clear dirty bit anyway to avoid infinite
656                                  * loop here.
657                                  */
658                                 clear_dquot_dirty(dquot);
659                                 if (!ret)
660                                         ret = err;
661                         }
662                         dqput(dquot);
663                         spin_lock(&dq_list_lock);
664                 }
665                 spin_unlock(&dq_list_lock);
666         }
667 
668         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
669                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
670                     && info_dirty(&dqopt->info[cnt]))
671                         sb->dq_op->write_info(sb, cnt);
672         dqstats_inc(DQST_SYNCS);
673 
674         return ret;
675 }
676 EXPORT_SYMBOL(dquot_writeback_dquots);
677 
678 /* Write all dquot structures to disk and make them visible from userspace */
679 int dquot_quota_sync(struct super_block *sb, int type)
680 {
681         struct quota_info *dqopt = sb_dqopt(sb);
682         int cnt;
683         int ret;
684 
685         ret = dquot_writeback_dquots(sb, type);
686         if (ret)
687                 return ret;
688         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
689                 return 0;
690 
691         /* This is not very clever (and fast) but currently I don't know about
692          * any other simple way of getting quota data to disk and we must get
693          * them there for userspace to be visible... */
694         if (sb->s_op->sync_fs)
695                 sb->s_op->sync_fs(sb, 1);
696         sync_blockdev(sb->s_bdev);
697 
698         /*
699          * Now when everything is written we can discard the pagecache so
700          * that userspace sees the changes.
701          */
702         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
703                 if (type != -1 && cnt != type)
704                         continue;
705                 if (!sb_has_quota_active(sb, cnt))
706                         continue;
707                 inode_lock(dqopt->files[cnt]);
708                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
709                 inode_unlock(dqopt->files[cnt]);
710         }
711 
712         return 0;
713 }
714 EXPORT_SYMBOL(dquot_quota_sync);
715 
716 static unsigned long
717 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
718 {
719         struct dquot *dquot;
720         unsigned long freed = 0;
721 
722         spin_lock(&dq_list_lock);
723         while (!list_empty(&free_dquots) && sc->nr_to_scan) {
724                 dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
725                 remove_dquot_hash(dquot);
726                 remove_free_dquot(dquot);
727                 remove_inuse(dquot);
728                 do_destroy_dquot(dquot);
729                 sc->nr_to_scan--;
730                 freed++;
731         }
732         spin_unlock(&dq_list_lock);
733         return freed;
734 }
735 
736 static unsigned long
737 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
738 {
739         return vfs_pressure_ratio(
740         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
741 }
742 
743 static struct shrinker dqcache_shrinker = {
744         .count_objects = dqcache_shrink_count,
745         .scan_objects = dqcache_shrink_scan,
746         .seeks = DEFAULT_SEEKS,
747 };
748 
749 /*
750  * Put reference to dquot
751  */
752 void dqput(struct dquot *dquot)
753 {
754         int ret;
755 
756         if (!dquot)
757                 return;
758 #ifdef CONFIG_QUOTA_DEBUG
759         if (!atomic_read(&dquot->dq_count)) {
760                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
761                             quotatypes[dquot->dq_id.type],
762                             from_kqid(&init_user_ns, dquot->dq_id));
763                 BUG();
764         }
765 #endif
766         dqstats_inc(DQST_DROPS);
767 we_slept:
768         spin_lock(&dq_list_lock);
769         if (atomic_read(&dquot->dq_count) > 1) {
770                 /* We have more than one user... nothing to do */
771                 atomic_dec(&dquot->dq_count);
772                 /* Releasing dquot during quotaoff phase? */
773                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
774                     atomic_read(&dquot->dq_count) == 1)
775                         wake_up(&dquot_ref_wq);
776                 spin_unlock(&dq_list_lock);
777                 return;
778         }
779         /* Need to release dquot? */
780         if (dquot_dirty(dquot)) {
781                 spin_unlock(&dq_list_lock);
782                 /* Commit dquot before releasing */
783                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
784                 if (ret < 0) {
785                         quota_error(dquot->dq_sb, "Can't write quota structure"
786                                     " (error %d). Quota may get out of sync!",
787                                     ret);
788                         /*
789                          * We clear dirty bit anyway, so that we avoid
790                          * infinite loop here
791                          */
792                         clear_dquot_dirty(dquot);
793                 }
794                 goto we_slept;
795         }
796         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
797                 spin_unlock(&dq_list_lock);
798                 dquot->dq_sb->dq_op->release_dquot(dquot);
799                 goto we_slept;
800         }
801         atomic_dec(&dquot->dq_count);
802 #ifdef CONFIG_QUOTA_DEBUG
803         /* sanity check */
804         BUG_ON(!list_empty(&dquot->dq_free));
805 #endif
806         put_dquot_last(dquot);
807         spin_unlock(&dq_list_lock);
808 }
809 EXPORT_SYMBOL(dqput);
810 
811 struct dquot *dquot_alloc(struct super_block *sb, int type)
812 {
813         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
814 }
815 EXPORT_SYMBOL(dquot_alloc);
816 
817 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
818 {
819         struct dquot *dquot;
820 
821         dquot = sb->dq_op->alloc_dquot(sb, type);
822         if(!dquot)
823                 return NULL;
824 
825         mutex_init(&dquot->dq_lock);
826         INIT_LIST_HEAD(&dquot->dq_free);
827         INIT_LIST_HEAD(&dquot->dq_inuse);
828         INIT_HLIST_NODE(&dquot->dq_hash);
829         INIT_LIST_HEAD(&dquot->dq_dirty);
830         dquot->dq_sb = sb;
831         dquot->dq_id = make_kqid_invalid(type);
832         atomic_set(&dquot->dq_count, 1);
833         spin_lock_init(&dquot->dq_dqb_lock);
834 
835         return dquot;
836 }
837 
838 /*
839  * Get reference to dquot
840  *
841  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
842  * destroying our dquot by:
843  *   a) checking for quota flags under dq_list_lock and
844  *   b) getting a reference to dquot before we release dq_list_lock
845  */
846 struct dquot *dqget(struct super_block *sb, struct kqid qid)
847 {
848         unsigned int hashent = hashfn(sb, qid);
849         struct dquot *dquot, *empty = NULL;
850 
851         if (!qid_has_mapping(sb->s_user_ns, qid))
852                 return ERR_PTR(-EINVAL);
853 
854         if (!sb_has_quota_active(sb, qid.type))
855                 return ERR_PTR(-ESRCH);
856 we_slept:
857         spin_lock(&dq_list_lock);
858         spin_lock(&dq_state_lock);
859         if (!sb_has_quota_active(sb, qid.type)) {
860                 spin_unlock(&dq_state_lock);
861                 spin_unlock(&dq_list_lock);
862                 dquot = ERR_PTR(-ESRCH);
863                 goto out;
864         }
865         spin_unlock(&dq_state_lock);
866 
867         dquot = find_dquot(hashent, sb, qid);
868         if (!dquot) {
869                 if (!empty) {
870                         spin_unlock(&dq_list_lock);
871                         empty = get_empty_dquot(sb, qid.type);
872                         if (!empty)
873                                 schedule();     /* Try to wait for a moment... */
874                         goto we_slept;
875                 }
876                 dquot = empty;
877                 empty = NULL;
878                 dquot->dq_id = qid;
879                 /* all dquots go on the inuse_list */
880                 put_inuse(dquot);
881                 /* hash it first so it can be found */
882                 insert_dquot_hash(dquot);
883                 spin_unlock(&dq_list_lock);
884                 dqstats_inc(DQST_LOOKUPS);
885         } else {
886                 if (!atomic_read(&dquot->dq_count))
887                         remove_free_dquot(dquot);
888                 atomic_inc(&dquot->dq_count);
889                 spin_unlock(&dq_list_lock);
890                 dqstats_inc(DQST_CACHE_HITS);
891                 dqstats_inc(DQST_LOOKUPS);
892         }
893         /* Wait for dq_lock - after this we know that either dquot_release() is
894          * already finished or it will be canceled due to dq_count > 1 test */
895         wait_on_dquot(dquot);
896         /* Read the dquot / allocate space in quota file */
897         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
898                 int err;
899 
900                 err = sb->dq_op->acquire_dquot(dquot);
901                 if (err < 0) {
902                         dqput(dquot);
903                         dquot = ERR_PTR(err);
904                         goto out;
905                 }
906         }
907         /*
908          * Make sure following reads see filled structure - paired with
909          * smp_mb__before_atomic() in dquot_acquire().
910          */
911         smp_rmb();
912 #ifdef CONFIG_QUOTA_DEBUG
913         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
914 #endif
915 out:
916         if (empty)
917                 do_destroy_dquot(empty);
918 
919         return dquot;
920 }
921 EXPORT_SYMBOL(dqget);
922 
923 static inline struct dquot **i_dquot(struct inode *inode)
924 {
925         return inode->i_sb->s_op->get_dquots(inode);
926 }
927 
928 static int dqinit_needed(struct inode *inode, int type)
929 {
930         struct dquot * const *dquots;
931         int cnt;
932 
933         if (IS_NOQUOTA(inode))
934                 return 0;
935 
936         dquots = i_dquot(inode);
937         if (type != -1)
938                 return !dquots[type];
939         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
940                 if (!dquots[cnt])
941                         return 1;
942         return 0;
943 }
944 
945 /* This routine is guarded by s_umount semaphore */
946 static int add_dquot_ref(struct super_block *sb, int type)
947 {
948         struct inode *inode, *old_inode = NULL;
949 #ifdef CONFIG_QUOTA_DEBUG
950         int reserved = 0;
951 #endif
952         int err = 0;
953 
954         spin_lock(&sb->s_inode_list_lock);
955         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
956                 spin_lock(&inode->i_lock);
957                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
958                     !atomic_read(&inode->i_writecount) ||
959                     !dqinit_needed(inode, type)) {
960                         spin_unlock(&inode->i_lock);
961                         continue;
962                 }
963                 __iget(inode);
964                 spin_unlock(&inode->i_lock);
965                 spin_unlock(&sb->s_inode_list_lock);
966 
967 #ifdef CONFIG_QUOTA_DEBUG
968                 if (unlikely(inode_get_rsv_space(inode) > 0))
969                         reserved = 1;
970 #endif
971                 iput(old_inode);
972                 err = __dquot_initialize(inode, type);
973                 if (err) {
974                         iput(inode);
975                         goto out;
976                 }
977 
978                 /*
979                  * We hold a reference to 'inode' so it couldn't have been
980                  * removed from s_inodes list while we dropped the
981                  * s_inode_list_lock. We cannot iput the inode now as we can be
982                  * holding the last reference and we cannot iput it under
983                  * s_inode_list_lock. So we keep the reference and iput it
984                  * later.
985                  */
986                 old_inode = inode;
987                 cond_resched();
988                 spin_lock(&sb->s_inode_list_lock);
989         }
990         spin_unlock(&sb->s_inode_list_lock);
991         iput(old_inode);
992 out:
993 #ifdef CONFIG_QUOTA_DEBUG
994         if (reserved) {
995                 quota_error(sb, "Writes happened before quota was turned on "
996                         "thus quota information is probably inconsistent. "
997                         "Please run quotacheck(8)");
998         }
999 #endif
1000         return err;
1001 }
1002 
1003 /*
1004  * Remove references to dquots from inode and add dquot to list for freeing
1005  * if we have the last reference to dquot
1006  */
1007 static void remove_inode_dquot_ref(struct inode *inode, int type,
1008                                    struct list_head *tofree_head)
1009 {
1010         struct dquot **dquots = i_dquot(inode);
1011         struct dquot *dquot = dquots[type];
1012 
1013         if (!dquot)
1014                 return;
1015 
1016         dquots[type] = NULL;
1017         if (list_empty(&dquot->dq_free)) {
1018                 /*
1019                  * The inode still has reference to dquot so it can't be in the
1020                  * free list
1021                  */
1022                 spin_lock(&dq_list_lock);
1023                 list_add(&dquot->dq_free, tofree_head);
1024                 spin_unlock(&dq_list_lock);
1025         } else {
1026                 /*
1027                  * Dquot is already in a list to put so we won't drop the last
1028                  * reference here.
1029                  */
1030                 dqput(dquot);
1031         }
1032 }
1033 
1034 /*
1035  * Free list of dquots
1036  * Dquots are removed from inodes and no new references can be got so we are
1037  * the only ones holding reference
1038  */
1039 static void put_dquot_list(struct list_head *tofree_head)
1040 {
1041         struct list_head *act_head;
1042         struct dquot *dquot;
1043 
1044         act_head = tofree_head->next;
1045         while (act_head != tofree_head) {
1046                 dquot = list_entry(act_head, struct dquot, dq_free);
1047                 act_head = act_head->next;
1048                 /* Remove dquot from the list so we won't have problems... */
1049                 list_del_init(&dquot->dq_free);
1050                 dqput(dquot);
1051         }
1052 }
1053 
1054 static void remove_dquot_ref(struct super_block *sb, int type,
1055                 struct list_head *tofree_head)
1056 {
1057         struct inode *inode;
1058 #ifdef CONFIG_QUOTA_DEBUG
1059         int reserved = 0;
1060 #endif
1061 
1062         spin_lock(&sb->s_inode_list_lock);
1063         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1064                 /*
1065                  *  We have to scan also I_NEW inodes because they can already
1066                  *  have quota pointer initialized. Luckily, we need to touch
1067                  *  only quota pointers and these have separate locking
1068                  *  (dq_data_lock).
1069                  */
1070                 spin_lock(&dq_data_lock);
1071                 if (!IS_NOQUOTA(inode)) {
1072 #ifdef CONFIG_QUOTA_DEBUG
1073                         if (unlikely(inode_get_rsv_space(inode) > 0))
1074                                 reserved = 1;
1075 #endif
1076                         remove_inode_dquot_ref(inode, type, tofree_head);
1077                 }
1078                 spin_unlock(&dq_data_lock);
1079         }
1080         spin_unlock(&sb->s_inode_list_lock);
1081 #ifdef CONFIG_QUOTA_DEBUG
1082         if (reserved) {
1083                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1084                         " was disabled thus quota information is probably "
1085                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1086         }
1087 #endif
1088 }
1089 
1090 /* Gather all references from inodes and drop them */
1091 static void drop_dquot_ref(struct super_block *sb, int type)
1092 {
1093         LIST_HEAD(tofree_head);
1094 
1095         if (sb->dq_op) {
1096                 remove_dquot_ref(sb, type, &tofree_head);
1097                 synchronize_srcu(&dquot_srcu);
1098                 put_dquot_list(&tofree_head);
1099         }
1100 }
1101 
1102 static inline
1103 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1104 {
1105         if (dquot->dq_dqb.dqb_rsvspace >= number)
1106                 dquot->dq_dqb.dqb_rsvspace -= number;
1107         else {
1108                 WARN_ON_ONCE(1);
1109                 dquot->dq_dqb.dqb_rsvspace = 0;
1110         }
1111         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1112             dquot->dq_dqb.dqb_bsoftlimit)
1113                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1114         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1115 }
1116 
1117 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1118 {
1119         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1120             dquot->dq_dqb.dqb_curinodes >= number)
1121                 dquot->dq_dqb.dqb_curinodes -= number;
1122         else
1123                 dquot->dq_dqb.dqb_curinodes = 0;
1124         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1125                 dquot->dq_dqb.dqb_itime = (time64_t) 0;
1126         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1127 }
1128 
1129 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1130 {
1131         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1132             dquot->dq_dqb.dqb_curspace >= number)
1133                 dquot->dq_dqb.dqb_curspace -= number;
1134         else
1135                 dquot->dq_dqb.dqb_curspace = 0;
1136         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1137             dquot->dq_dqb.dqb_bsoftlimit)
1138                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1139         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1140 }
1141 
1142 struct dquot_warn {
1143         struct super_block *w_sb;
1144         struct kqid w_dq_id;
1145         short w_type;
1146 };
1147 
1148 static int warning_issued(struct dquot *dquot, const int warntype)
1149 {
1150         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1151                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1152                 ((warntype == QUOTA_NL_IHARDWARN ||
1153                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1154 
1155         if (!flag)
1156                 return 0;
1157         return test_and_set_bit(flag, &dquot->dq_flags);
1158 }
1159 
1160 #ifdef CONFIG_PRINT_QUOTA_WARNING
1161 static int flag_print_warnings = 1;
1162 
1163 static int need_print_warning(struct dquot_warn *warn)
1164 {
1165         if (!flag_print_warnings)
1166                 return 0;
1167 
1168         switch (warn->w_dq_id.type) {
1169                 case USRQUOTA:
1170                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1171                 case GRPQUOTA:
1172                         return in_group_p(warn->w_dq_id.gid);
1173                 case PRJQUOTA:
1174                         return 1;
1175         }
1176         return 0;
1177 }
1178 
1179 /* Print warning to user which exceeded quota */
1180 static void print_warning(struct dquot_warn *warn)
1181 {
1182         char *msg = NULL;
1183         struct tty_struct *tty;
1184         int warntype = warn->w_type;
1185 
1186         if (warntype == QUOTA_NL_IHARDBELOW ||
1187             warntype == QUOTA_NL_ISOFTBELOW ||
1188             warntype == QUOTA_NL_BHARDBELOW ||
1189             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1190                 return;
1191 
1192         tty = get_current_tty();
1193         if (!tty)
1194                 return;
1195         tty_write_message(tty, warn->w_sb->s_id);
1196         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1197                 tty_write_message(tty, ": warning, ");
1198         else
1199                 tty_write_message(tty, ": write failed, ");
1200         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1201         switch (warntype) {
1202                 case QUOTA_NL_IHARDWARN:
1203                         msg = " file limit reached.\r\n";
1204                         break;
1205                 case QUOTA_NL_ISOFTLONGWARN:
1206                         msg = " file quota exceeded too long.\r\n";
1207                         break;
1208                 case QUOTA_NL_ISOFTWARN:
1209                         msg = " file quota exceeded.\r\n";
1210                         break;
1211                 case QUOTA_NL_BHARDWARN:
1212                         msg = " block limit reached.\r\n";
1213                         break;
1214                 case QUOTA_NL_BSOFTLONGWARN:
1215                         msg = " block quota exceeded too long.\r\n";
1216                         break;
1217                 case QUOTA_NL_BSOFTWARN:
1218                         msg = " block quota exceeded.\r\n";
1219                         break;
1220         }
1221         tty_write_message(tty, msg);
1222         tty_kref_put(tty);
1223 }
1224 #endif
1225 
1226 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1227                             int warntype)
1228 {
1229         if (warning_issued(dquot, warntype))
1230                 return;
1231         warn->w_type = warntype;
1232         warn->w_sb = dquot->dq_sb;
1233         warn->w_dq_id = dquot->dq_id;
1234 }
1235 
1236 /*
1237  * Write warnings to the console and send warning messages over netlink.
1238  *
1239  * Note that this function can call into tty and networking code.
1240  */
1241 static void flush_warnings(struct dquot_warn *warn)
1242 {
1243         int i;
1244 
1245         for (i = 0; i < MAXQUOTAS; i++) {
1246                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1247                         continue;
1248 #ifdef CONFIG_PRINT_QUOTA_WARNING
1249                 print_warning(&warn[i]);
1250 #endif
1251                 quota_send_warning(warn[i].w_dq_id,
1252                                    warn[i].w_sb->s_dev, warn[i].w_type);
1253         }
1254 }
1255 
1256 static int ignore_hardlimit(struct dquot *dquot)
1257 {
1258         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1259 
1260         return capable(CAP_SYS_RESOURCE) &&
1261                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1262                 !(info->dqi_flags & DQF_ROOT_SQUASH));
1263 }
1264 
1265 static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
1266                             struct dquot_warn *warn)
1267 {
1268         qsize_t newinodes;
1269         int ret = 0;
1270 
1271         spin_lock(&dquot->dq_dqb_lock);
1272         newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1273         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1274             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1275                 goto add;
1276 
1277         if (dquot->dq_dqb.dqb_ihardlimit &&
1278             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1279             !ignore_hardlimit(dquot)) {
1280                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1281                 ret = -EDQUOT;
1282                 goto out;
1283         }
1284 
1285         if (dquot->dq_dqb.dqb_isoftlimit &&
1286             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1287             dquot->dq_dqb.dqb_itime &&
1288             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
1289             !ignore_hardlimit(dquot)) {
1290                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1291                 ret = -EDQUOT;
1292                 goto out;
1293         }
1294 
1295         if (dquot->dq_dqb.dqb_isoftlimit &&
1296             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1297             dquot->dq_dqb.dqb_itime == 0) {
1298                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
1299                 dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
1300                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
1301         }
1302 add:
1303         dquot->dq_dqb.dqb_curinodes = newinodes;
1304 
1305 out:
1306         spin_unlock(&dquot->dq_dqb_lock);
1307         return ret;
1308 }
1309 
1310 static int dquot_add_space(struct dquot *dquot, qsize_t space,
1311                            qsize_t rsv_space, unsigned int flags,
1312                            struct dquot_warn *warn)
1313 {
1314         qsize_t tspace;
1315         struct super_block *sb = dquot->dq_sb;
1316         int ret = 0;
1317 
1318         spin_lock(&dquot->dq_dqb_lock);
1319         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1320             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1321                 goto finish;
1322 
1323         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1324                 + space + rsv_space;
1325 
1326         if (dquot->dq_dqb.dqb_bhardlimit &&
1327             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1328             !ignore_hardlimit(dquot)) {
1329                 if (flags & DQUOT_SPACE_WARN)
1330                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1331                 ret = -EDQUOT;
1332                 goto finish;
1333         }
1334 
1335         if (dquot->dq_dqb.dqb_bsoftlimit &&
1336             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1337             dquot->dq_dqb.dqb_btime &&
1338             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
1339             !ignore_hardlimit(dquot)) {
1340                 if (flags & DQUOT_SPACE_WARN)
1341                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1342                 ret = -EDQUOT;
1343                 goto finish;
1344         }
1345 
1346         if (dquot->dq_dqb.dqb_bsoftlimit &&
1347             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1348             dquot->dq_dqb.dqb_btime == 0) {
1349                 if (flags & DQUOT_SPACE_WARN) {
1350                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1351                         dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
1352                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1353                 } else {
1354                         /*
1355                          * We don't allow preallocation to exceed softlimit so exceeding will
1356                          * be always printed
1357                          */
1358                         ret = -EDQUOT;
1359                         goto finish;
1360                 }
1361         }
1362 finish:
1363         /*
1364          * We have to be careful and go through warning generation & grace time
1365          * setting even if DQUOT_SPACE_NOFAIL is set. That's why we check it
1366          * only here...
1367          */
1368         if (flags & DQUOT_SPACE_NOFAIL)
1369                 ret = 0;
1370         if (!ret) {
1371                 dquot->dq_dqb.dqb_rsvspace += rsv_space;
1372                 dquot->dq_dqb.dqb_curspace += space;
1373         }
1374         spin_unlock(&dquot->dq_dqb_lock);
1375         return ret;
1376 }
1377 
1378 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1379 {
1380         qsize_t newinodes;
1381 
1382         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1383             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1384             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1385                 return QUOTA_NL_NOWARN;
1386 
1387         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1388         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1389                 return QUOTA_NL_ISOFTBELOW;
1390         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1391             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1392                 return QUOTA_NL_IHARDBELOW;
1393         return QUOTA_NL_NOWARN;
1394 }
1395 
1396 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1397 {
1398         qsize_t tspace;
1399 
1400         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace;
1401 
1402         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1403             tspace <= dquot->dq_dqb.dqb_bsoftlimit)
1404                 return QUOTA_NL_NOWARN;
1405 
1406         if (tspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1407                 return QUOTA_NL_BSOFTBELOW;
1408         if (tspace >= dquot->dq_dqb.dqb_bhardlimit &&
1409             tspace - space < dquot->dq_dqb.dqb_bhardlimit)
1410                 return QUOTA_NL_BHARDBELOW;
1411         return QUOTA_NL_NOWARN;
1412 }
1413 
1414 static int dquot_active(const struct inode *inode)
1415 {
1416         struct super_block *sb = inode->i_sb;
1417 
1418         if (IS_NOQUOTA(inode))
1419                 return 0;
1420         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1421 }
1422 
1423 /*
1424  * Initialize quota pointers in inode
1425  *
1426  * It is better to call this function outside of any transaction as it
1427  * might need a lot of space in journal for dquot structure allocation.
1428  */
1429 static int __dquot_initialize(struct inode *inode, int type)
1430 {
1431         int cnt, init_needed = 0;
1432         struct dquot **dquots, *got[MAXQUOTAS] = {};
1433         struct super_block *sb = inode->i_sb;
1434         qsize_t rsv;
1435         int ret = 0;
1436 
1437         if (!dquot_active(inode))
1438                 return 0;
1439 
1440         dquots = i_dquot(inode);
1441 
1442         /* First get references to structures we might need. */
1443         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1444                 struct kqid qid;
1445                 kprojid_t projid;
1446                 int rc;
1447                 struct dquot *dquot;
1448 
1449                 if (type != -1 && cnt != type)
1450                         continue;
1451                 /*
1452                  * The i_dquot should have been initialized in most cases,
1453                  * we check it without locking here to avoid unnecessary
1454                  * dqget()/dqput() calls.
1455                  */
1456                 if (dquots[cnt])
1457                         continue;
1458 
1459                 if (!sb_has_quota_active(sb, cnt))
1460                         continue;
1461 
1462                 init_needed = 1;
1463 
1464                 switch (cnt) {
1465                 case USRQUOTA:
1466                         qid = make_kqid_uid(inode->i_uid);
1467                         break;
1468                 case GRPQUOTA:
1469                         qid = make_kqid_gid(inode->i_gid);
1470                         break;
1471                 case PRJQUOTA:
1472                         rc = inode->i_sb->dq_op->get_projid(inode, &projid);
1473                         if (rc)
1474                                 continue;
1475                         qid = make_kqid_projid(projid);
1476                         break;
1477                 }
1478                 dquot = dqget(sb, qid);
1479                 if (IS_ERR(dquot)) {
1480                         /* We raced with somebody turning quotas off... */
1481                         if (PTR_ERR(dquot) != -ESRCH) {
1482                                 ret = PTR_ERR(dquot);
1483                                 goto out_put;
1484                         }
1485                         dquot = NULL;
1486                 }
1487                 got[cnt] = dquot;
1488         }
1489 
1490         /* All required i_dquot has been initialized */
1491         if (!init_needed)
1492                 return 0;
1493 
1494         spin_lock(&dq_data_lock);
1495         if (IS_NOQUOTA(inode))
1496                 goto out_lock;
1497         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1498                 if (type != -1 && cnt != type)
1499                         continue;
1500                 /* Avoid races with quotaoff() */
1501                 if (!sb_has_quota_active(sb, cnt))
1502                         continue;
1503                 /* We could race with quotaon or dqget() could have failed */
1504                 if (!got[cnt])
1505                         continue;
1506                 if (!dquots[cnt]) {
1507                         dquots[cnt] = got[cnt];
1508                         got[cnt] = NULL;
1509                         /*
1510                          * Make quota reservation system happy if someone
1511                          * did a write before quota was turned on
1512                          */
1513                         rsv = inode_get_rsv_space(inode);
1514                         if (unlikely(rsv)) {
1515                                 spin_lock(&inode->i_lock);
1516                                 /* Get reservation again under proper lock */
1517                                 rsv = __inode_get_rsv_space(inode);
1518                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1519                                 dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
1520                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1521                                 spin_unlock(&inode->i_lock);
1522                         }
1523                 }
1524         }
1525 out_lock:
1526         spin_unlock(&dq_data_lock);
1527 out_put:
1528         /* Drop unused references */
1529         dqput_all(got);
1530 
1531         return ret;
1532 }
1533 
1534 int dquot_initialize(struct inode *inode)
1535 {
1536         return __dquot_initialize(inode, -1);
1537 }
1538 EXPORT_SYMBOL(dquot_initialize);
1539 
1540 bool dquot_initialize_needed(struct inode *inode)
1541 {
1542         struct dquot **dquots;
1543         int i;
1544 
1545         if (!dquot_active(inode))
1546                 return false;
1547 
1548         dquots = i_dquot(inode);
1549         for (i = 0; i < MAXQUOTAS; i++)
1550                 if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
1551                         return true;
1552         return false;
1553 }
1554 EXPORT_SYMBOL(dquot_initialize_needed);
1555 
1556 /*
1557  * Release all quotas referenced by inode.
1558  *
1559  * This function only be called on inode free or converting
1560  * a file to quota file, no other users for the i_dquot in
1561  * both cases, so we needn't call synchronize_srcu() after
1562  * clearing i_dquot.
1563  */
1564 static void __dquot_drop(struct inode *inode)
1565 {
1566         int cnt;
1567         struct dquot **dquots = i_dquot(inode);
1568         struct dquot *put[MAXQUOTAS];
1569 
1570         spin_lock(&dq_data_lock);
1571         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1572                 put[cnt] = dquots[cnt];
1573                 dquots[cnt] = NULL;
1574         }
1575         spin_unlock(&dq_data_lock);
1576         dqput_all(put);
1577 }
1578 
1579 void dquot_drop(struct inode *inode)
1580 {
1581         struct dquot * const *dquots;
1582         int cnt;
1583 
1584         if (IS_NOQUOTA(inode))
1585                 return;
1586 
1587         /*
1588          * Test before calling to rule out calls from proc and such
1589          * where we are not allowed to block. Note that this is
1590          * actually reliable test even without the lock - the caller
1591          * must assure that nobody can come after the DQUOT_DROP and
1592          * add quota pointers back anyway.
1593          */
1594         dquots = i_dquot(inode);
1595         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1596                 if (dquots[cnt])
1597                         break;
1598         }
1599 
1600         if (cnt < MAXQUOTAS)
1601                 __dquot_drop(inode);
1602 }
1603 EXPORT_SYMBOL(dquot_drop);
1604 
1605 /*
1606  * inode_reserved_space is managed internally by quota, and protected by
1607  * i_lock similar to i_blocks+i_bytes.
1608  */
1609 static qsize_t *inode_reserved_space(struct inode * inode)
1610 {
1611         /* Filesystem must explicitly define it's own method in order to use
1612          * quota reservation interface */
1613         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1614         return inode->i_sb->dq_op->get_reserved_space(inode);
1615 }
1616 
1617 static qsize_t __inode_get_rsv_space(struct inode *inode)
1618 {
1619         if (!inode->i_sb->dq_op->get_reserved_space)
1620                 return 0;
1621         return *inode_reserved_space(inode);
1622 }
1623 
1624 static qsize_t inode_get_rsv_space(struct inode *inode)
1625 {
1626         qsize_t ret;
1627 
1628         if (!inode->i_sb->dq_op->get_reserved_space)
1629                 return 0;
1630         spin_lock(&inode->i_lock);
1631         ret = __inode_get_rsv_space(inode);
1632         spin_unlock(&inode->i_lock);
1633         return ret;
1634 }
1635 
1636 /*
1637  * This functions updates i_blocks+i_bytes fields and quota information
1638  * (together with appropriate checks).
1639  *
1640  * NOTE: We absolutely rely on the fact that caller dirties the inode
1641  * (usually helpers in quotaops.h care about this) and holds a handle for
1642  * the current transaction so that dquot write and inode write go into the
1643  * same transaction.
1644  */
1645 
1646 /*
1647  * This operation can block, but only after everything is updated
1648  */
1649 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1650 {
1651         int cnt, ret = 0, index;
1652         struct dquot_warn warn[MAXQUOTAS];
1653         int reserve = flags & DQUOT_SPACE_RESERVE;
1654         struct dquot **dquots;
1655 
1656         if (!dquot_active(inode)) {
1657                 if (reserve) {
1658                         spin_lock(&inode->i_lock);
1659                         *inode_reserved_space(inode) += number;
1660                         spin_unlock(&inode->i_lock);
1661                 } else {
1662                         inode_add_bytes(inode, number);
1663                 }
1664                 goto out;
1665         }
1666 
1667         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1668                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1669 
1670         dquots = i_dquot(inode);
1671         index = srcu_read_lock(&dquot_srcu);
1672         spin_lock(&inode->i_lock);
1673         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1674                 if (!dquots[cnt])
1675                         continue;
1676                 if (reserve) {
1677                         ret = dquot_add_space(dquots[cnt], 0, number, flags,
1678                                               &warn[cnt]);
1679                 } else {
1680                         ret = dquot_add_space(dquots[cnt], number, 0, flags,
1681                                               &warn[cnt]);
1682                 }
1683                 if (ret) {
1684                         /* Back out changes we already did */
1685                         for (cnt--; cnt >= 0; cnt--) {
1686                                 if (!dquots[cnt])
1687                                         continue;
1688                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1689                                 if (reserve)
1690                                         dquot_free_reserved_space(dquots[cnt],
1691                                                                   number);
1692                                 else
1693                                         dquot_decr_space(dquots[cnt], number);
1694                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1695                         }
1696                         spin_unlock(&inode->i_lock);
1697                         goto out_flush_warn;
1698                 }
1699         }
1700         if (reserve)
1701                 *inode_reserved_space(inode) += number;
1702         else
1703                 __inode_add_bytes(inode, number);
1704         spin_unlock(&inode->i_lock);
1705 
1706         if (reserve)
1707                 goto out_flush_warn;
1708         mark_all_dquot_dirty(dquots);
1709 out_flush_warn:
1710         srcu_read_unlock(&dquot_srcu, index);
1711         flush_warnings(warn);
1712 out:
1713         return ret;
1714 }
1715 EXPORT_SYMBOL(__dquot_alloc_space);
1716 
1717 /*
1718  * This operation can block, but only after everything is updated
1719  */
1720 int dquot_alloc_inode(struct inode *inode)
1721 {
1722         int cnt, ret = 0, index;
1723         struct dquot_warn warn[MAXQUOTAS];
1724         struct dquot * const *dquots;
1725 
1726         if (!dquot_active(inode))
1727                 return 0;
1728         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1729                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1730 
1731         dquots = i_dquot(inode);
1732         index = srcu_read_lock(&dquot_srcu);
1733         spin_lock(&inode->i_lock);
1734         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1735                 if (!dquots[cnt])
1736                         continue;
1737                 ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
1738                 if (ret) {
1739                         for (cnt--; cnt >= 0; cnt--) {
1740                                 if (!dquots[cnt])
1741                                         continue;
1742                                 /* Back out changes we already did */
1743                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1744                                 dquot_decr_inodes(dquots[cnt], 1);
1745                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1746                         }
1747                         goto warn_put_all;
1748                 }
1749         }
1750 
1751 warn_put_all:
1752         spin_unlock(&inode->i_lock);
1753         if (ret == 0)
1754                 mark_all_dquot_dirty(dquots);
1755         srcu_read_unlock(&dquot_srcu, index);
1756         flush_warnings(warn);
1757         return ret;
1758 }
1759 EXPORT_SYMBOL(dquot_alloc_inode);
1760 
1761 /*
1762  * Convert in-memory reserved quotas to real consumed quotas
1763  */
1764 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1765 {
1766         struct dquot **dquots;
1767         int cnt, index;
1768 
1769         if (!dquot_active(inode)) {
1770                 spin_lock(&inode->i_lock);
1771                 *inode_reserved_space(inode) -= number;
1772                 __inode_add_bytes(inode, number);
1773                 spin_unlock(&inode->i_lock);
1774                 return 0;
1775         }
1776 
1777         dquots = i_dquot(inode);
1778         index = srcu_read_lock(&dquot_srcu);
1779         spin_lock(&inode->i_lock);
1780         /* Claim reserved quotas to allocated quotas */
1781         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1782                 if (dquots[cnt]) {
1783                         struct dquot *dquot = dquots[cnt];
1784 
1785                         spin_lock(&dquot->dq_dqb_lock);
1786                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
1787                                 number = dquot->dq_dqb.dqb_rsvspace;
1788                         dquot->dq_dqb.dqb_curspace += number;
1789                         dquot->dq_dqb.dqb_rsvspace -= number;
1790                         spin_unlock(&dquot->dq_dqb_lock);
1791                 }
1792         }
1793         /* Update inode bytes */
1794         *inode_reserved_space(inode) -= number;
1795         __inode_add_bytes(inode, number);
1796         spin_unlock(&inode->i_lock);
1797         mark_all_dquot_dirty(dquots);
1798         srcu_read_unlock(&dquot_srcu, index);
1799         return 0;
1800 }
1801 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1802 
1803 /*
1804  * Convert allocated space back to in-memory reserved quotas
1805  */
1806 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1807 {
1808         struct dquot **dquots;
1809         int cnt, index;
1810 
1811         if (!dquot_active(inode)) {
1812                 spin_lock(&inode->i_lock);
1813                 *inode_reserved_space(inode) += number;
1814                 __inode_sub_bytes(inode, number);
1815                 spin_unlock(&inode->i_lock);
1816                 return;
1817         }
1818 
1819         dquots = i_dquot(inode);
1820         index = srcu_read_lock(&dquot_srcu);
1821         spin_lock(&inode->i_lock);
1822         /* Claim reserved quotas to allocated quotas */
1823         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1824                 if (dquots[cnt]) {
1825                         struct dquot *dquot = dquots[cnt];
1826 
1827                         spin_lock(&dquot->dq_dqb_lock);
1828                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1829                                 number = dquot->dq_dqb.dqb_curspace;
1830                         dquot->dq_dqb.dqb_rsvspace += number;
1831                         dquot->dq_dqb.dqb_curspace -= number;
1832                         spin_unlock(&dquot->dq_dqb_lock);
1833                 }
1834         }
1835         /* Update inode bytes */
1836         *inode_reserved_space(inode) += number;
1837         __inode_sub_bytes(inode, number);
1838         spin_unlock(&inode->i_lock);
1839         mark_all_dquot_dirty(dquots);
1840         srcu_read_unlock(&dquot_srcu, index);
1841         return;
1842 }
1843 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1844 
1845 /*
1846  * This operation can block, but only after everything is updated
1847  */
1848 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1849 {
1850         unsigned int cnt;
1851         struct dquot_warn warn[MAXQUOTAS];
1852         struct dquot **dquots;
1853         int reserve = flags & DQUOT_SPACE_RESERVE, index;
1854 
1855         if (!dquot_active(inode)) {
1856                 if (reserve) {
1857                         spin_lock(&inode->i_lock);
1858                         *inode_reserved_space(inode) -= number;
1859                         spin_unlock(&inode->i_lock);
1860                 } else {
1861                         inode_sub_bytes(inode, number);
1862                 }
1863                 return;
1864         }
1865 
1866         dquots = i_dquot(inode);
1867         index = srcu_read_lock(&dquot_srcu);
1868         spin_lock(&inode->i_lock);
1869         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1870                 int wtype;
1871 
1872                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1873                 if (!dquots[cnt])
1874                         continue;
1875                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1876                 wtype = info_bdq_free(dquots[cnt], number);
1877                 if (wtype != QUOTA_NL_NOWARN)
1878                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1879                 if (reserve)
1880                         dquot_free_reserved_space(dquots[cnt], number);
1881                 else
1882                         dquot_decr_space(dquots[cnt], number);
1883                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1884         }
1885         if (reserve)
1886                 *inode_reserved_space(inode) -= number;
1887         else
1888                 __inode_sub_bytes(inode, number);
1889         spin_unlock(&inode->i_lock);
1890 
1891         if (reserve)
1892                 goto out_unlock;
1893         mark_all_dquot_dirty(dquots);
1894 out_unlock:
1895         srcu_read_unlock(&dquot_srcu, index);
1896         flush_warnings(warn);
1897 }
1898 EXPORT_SYMBOL(__dquot_free_space);
1899 
1900 /*
1901  * This operation can block, but only after everything is updated
1902  */
1903 void dquot_free_inode(struct inode *inode)
1904 {
1905         unsigned int cnt;
1906         struct dquot_warn warn[MAXQUOTAS];
1907         struct dquot * const *dquots;
1908         int index;
1909 
1910         if (!dquot_active(inode))
1911                 return;
1912 
1913         dquots = i_dquot(inode);
1914         index = srcu_read_lock(&dquot_srcu);
1915         spin_lock(&inode->i_lock);
1916         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1917                 int wtype;
1918 
1919                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1920                 if (!dquots[cnt])
1921                         continue;
1922                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1923                 wtype = info_idq_free(dquots[cnt], 1);
1924                 if (wtype != QUOTA_NL_NOWARN)
1925                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1926                 dquot_decr_inodes(dquots[cnt], 1);
1927                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1928         }
1929         spin_unlock(&inode->i_lock);
1930         mark_all_dquot_dirty(dquots);
1931         srcu_read_unlock(&dquot_srcu, index);
1932         flush_warnings(warn);
1933 }
1934 EXPORT_SYMBOL(dquot_free_inode);
1935 
1936 /*
1937  * Transfer the number of inode and blocks from one diskquota to an other.
1938  * On success, dquot references in transfer_to are consumed and references
1939  * to original dquots that need to be released are placed there. On failure,
1940  * references are kept untouched.
1941  *
1942  * This operation can block, but only after everything is updated
1943  * A transaction must be started when entering this function.
1944  *
1945  * We are holding reference on transfer_from & transfer_to, no need to
1946  * protect them by srcu_read_lock().
1947  */
1948 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1949 {
1950         qsize_t cur_space;
1951         qsize_t rsv_space = 0;
1952         qsize_t inode_usage = 1;
1953         struct dquot *transfer_from[MAXQUOTAS] = {};
1954         int cnt, ret = 0;
1955         char is_valid[MAXQUOTAS] = {};
1956         struct dquot_warn warn_to[MAXQUOTAS];
1957         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1958         struct dquot_warn warn_from_space[MAXQUOTAS];
1959 
1960         if (IS_NOQUOTA(inode))
1961                 return 0;
1962 
1963         if (inode->i_sb->dq_op->get_inode_usage) {
1964                 ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
1965                 if (ret)
1966                         return ret;
1967         }
1968 
1969         /* Initialize the arrays */
1970         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1971                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
1972                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
1973                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
1974         }
1975 
1976         spin_lock(&dq_data_lock);
1977         spin_lock(&inode->i_lock);
1978         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1979                 spin_unlock(&inode->i_lock);
1980                 spin_unlock(&dq_data_lock);
1981                 return 0;
1982         }
1983         cur_space = __inode_get_bytes(inode);
1984         rsv_space = __inode_get_rsv_space(inode);
1985         /*
1986          * Build the transfer_from list, check limits, and update usage in
1987          * the target structures.
1988          */
1989         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1990                 /*
1991                  * Skip changes for same uid or gid or for turned off quota-type.
1992                  */
1993                 if (!transfer_to[cnt])
1994                         continue;
1995                 /* Avoid races with quotaoff() */
1996                 if (!sb_has_quota_active(inode->i_sb, cnt))
1997                         continue;
1998                 is_valid[cnt] = 1;
1999                 transfer_from[cnt] = i_dquot(inode)[cnt];
2000                 ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
2001                                        &warn_to[cnt]);
2002                 if (ret)
2003                         goto over_quota;
2004                 ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space,
2005                                       DQUOT_SPACE_WARN, &warn_to[cnt]);
2006                 if (ret) {
2007                         spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2008                         dquot_decr_inodes(transfer_to[cnt], inode_usage);
2009                         spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2010                         goto over_quota;
2011                 }
2012         }
2013 
2014         /* Decrease usage for source structures and update quota pointers */
2015         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2016                 if (!is_valid[cnt])
2017                         continue;
2018                 /* Due to IO error we might not have transfer_from[] structure */
2019                 if (transfer_from[cnt]) {
2020                         int wtype;
2021 
2022                         spin_lock(&transfer_from[cnt]->dq_dqb_lock);
2023                         wtype = info_idq_free(transfer_from[cnt], inode_usage);
2024                         if (wtype != QUOTA_NL_NOWARN)
2025                                 prepare_warning(&warn_from_inodes[cnt],
2026                                                 transfer_from[cnt], wtype);
2027                         wtype = info_bdq_free(transfer_from[cnt],
2028                                               cur_space + rsv_space);
2029                         if (wtype != QUOTA_NL_NOWARN)
2030                                 prepare_warning(&warn_from_space[cnt],
2031                                                 transfer_from[cnt], wtype);
2032                         dquot_decr_inodes(transfer_from[cnt], inode_usage);
2033                         dquot_decr_space(transfer_from[cnt], cur_space);
2034                         dquot_free_reserved_space(transfer_from[cnt],
2035                                                   rsv_space);
2036                         spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
2037                 }
2038                 i_dquot(inode)[cnt] = transfer_to[cnt];
2039         }
2040         spin_unlock(&inode->i_lock);
2041         spin_unlock(&dq_data_lock);
2042 
2043         mark_all_dquot_dirty(transfer_from);
2044         mark_all_dquot_dirty(transfer_to);
2045         flush_warnings(warn_to);
2046         flush_warnings(warn_from_inodes);
2047         flush_warnings(warn_from_space);
2048         /* Pass back references to put */
2049         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2050                 if (is_valid[cnt])
2051                         transfer_to[cnt] = transfer_from[cnt];
2052         return 0;
2053 over_quota:
2054         /* Back out changes we already did */
2055         for (cnt--; cnt >= 0; cnt--) {
2056                 if (!is_valid[cnt])
2057                         continue;
2058                 spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2059                 dquot_decr_inodes(transfer_to[cnt], inode_usage);
2060                 dquot_decr_space(transfer_to[cnt], cur_space);
2061                 dquot_free_reserved_space(transfer_to[cnt], rsv_space);
2062                 spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2063         }
2064         spin_unlock(&inode->i_lock);
2065         spin_unlock(&dq_data_lock);
2066         flush_warnings(warn_to);
2067         return ret;
2068 }
2069 EXPORT_SYMBOL(__dquot_transfer);
2070 
2071 /* Wrapper for transferring ownership of an inode for uid/gid only
2072  * Called from FSXXX_setattr()
2073  */
2074 int dquot_transfer(struct inode *inode, struct iattr *iattr)
2075 {
2076         struct dquot *transfer_to[MAXQUOTAS] = {};
2077         struct dquot *dquot;
2078         struct super_block *sb = inode->i_sb;
2079         int ret;
2080 
2081         if (!dquot_active(inode))
2082                 return 0;
2083 
2084         if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
2085                 dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
2086                 if (IS_ERR(dquot)) {
2087                         if (PTR_ERR(dquot) != -ESRCH) {
2088                                 ret = PTR_ERR(dquot);
2089                                 goto out_put;
2090                         }
2091                         dquot = NULL;
2092                 }
2093                 transfer_to[USRQUOTA] = dquot;
2094         }
2095         if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
2096                 dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
2097                 if (IS_ERR(dquot)) {
2098                         if (PTR_ERR(dquot) != -ESRCH) {
2099                                 ret = PTR_ERR(dquot);
2100                                 goto out_put;
2101                         }
2102                         dquot = NULL;
2103                 }
2104                 transfer_to[GRPQUOTA] = dquot;
2105         }
2106         ret = __dquot_transfer(inode, transfer_to);
2107 out_put:
2108         dqput_all(transfer_to);
2109         return ret;
2110 }
2111 EXPORT_SYMBOL(dquot_transfer);
2112 
2113 /*
2114  * Write info of quota file to disk
2115  */
2116 int dquot_commit_info(struct super_block *sb, int type)
2117 {
2118         struct quota_info *dqopt = sb_dqopt(sb);
2119 
2120         return dqopt->ops[type]->write_file_info(sb, type);
2121 }
2122 EXPORT_SYMBOL(dquot_commit_info);
2123 
2124 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
2125 {
2126         struct quota_info *dqopt = sb_dqopt(sb);
2127 
2128         if (!sb_has_quota_active(sb, qid->type))
2129                 return -ESRCH;
2130         if (!dqopt->ops[qid->type]->get_next_id)
2131                 return -ENOSYS;
2132         return dqopt->ops[qid->type]->get_next_id(sb, qid);
2133 }
2134 EXPORT_SYMBOL(dquot_get_next_id);
2135 
2136 /*
2137  * Definitions of diskquota operations.
2138  */
2139 const struct dquot_operations dquot_operations = {
2140         .write_dquot    = dquot_commit,
2141         .acquire_dquot  = dquot_acquire,
2142         .release_dquot  = dquot_release,
2143         .mark_dirty     = dquot_mark_dquot_dirty,
2144         .write_info     = dquot_commit_info,
2145         .alloc_dquot    = dquot_alloc,
2146         .destroy_dquot  = dquot_destroy,
2147         .get_next_id    = dquot_get_next_id,
2148 };
2149 EXPORT_SYMBOL(dquot_operations);
2150 
2151 /*
2152  * Generic helper for ->open on filesystems supporting disk quotas.
2153  */
2154 int dquot_file_open(struct inode *inode, struct file *file)
2155 {
2156         int error;
2157 
2158         error = generic_file_open(inode, file);
2159         if (!error && (file->f_mode & FMODE_WRITE))
2160                 error = dquot_initialize(inode);
2161         return error;
2162 }
2163 EXPORT_SYMBOL(dquot_file_open);
2164 
2165 static void vfs_cleanup_quota_inode(struct super_block *sb, int type)
2166 {
2167         struct quota_info *dqopt = sb_dqopt(sb);
2168         struct inode *inode = dqopt->files[type];
2169 
2170         if (!inode)
2171                 return;
2172         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2173                 inode_lock(inode);
2174                 inode->i_flags &= ~S_NOQUOTA;
2175                 inode_unlock(inode);
2176         }
2177         dqopt->files[type] = NULL;
2178         iput(inode);
2179 }
2180 
2181 /*
2182  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2183  */
2184 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2185 {
2186         int cnt;
2187         struct quota_info *dqopt = sb_dqopt(sb);
2188 
2189         /* s_umount should be held in exclusive mode */
2190         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2191                 up_read(&sb->s_umount);
2192 
2193         /* Cannot turn off usage accounting without turning off limits, or
2194          * suspend quotas and simultaneously turn quotas off. */
2195         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2196             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2197             DQUOT_USAGE_ENABLED)))
2198                 return -EINVAL;
2199 
2200         /*
2201          * Skip everything if there's nothing to do. We have to do this because
2202          * sometimes we are called when fill_super() failed and calling
2203          * sync_fs() in such cases does no good.
2204          */
2205         if (!sb_any_quota_loaded(sb))
2206                 return 0;
2207 
2208         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2209                 if (type != -1 && cnt != type)
2210                         continue;
2211                 if (!sb_has_quota_loaded(sb, cnt))
2212                         continue;
2213 
2214                 if (flags & DQUOT_SUSPENDED) {
2215                         spin_lock(&dq_state_lock);
2216                         dqopt->flags |=
2217                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2218                         spin_unlock(&dq_state_lock);
2219                 } else {
2220                         spin_lock(&dq_state_lock);
2221                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2222                         /* Turning off suspended quotas? */
2223                         if (!sb_has_quota_loaded(sb, cnt) &&
2224                             sb_has_quota_suspended(sb, cnt)) {
2225                                 dqopt->flags &= ~dquot_state_flag(
2226                                                         DQUOT_SUSPENDED, cnt);
2227                                 spin_unlock(&dq_state_lock);
2228                                 vfs_cleanup_quota_inode(sb, cnt);
2229                                 continue;
2230                         }
2231                         spin_unlock(&dq_state_lock);
2232                 }
2233 
2234                 /* We still have to keep quota loaded? */
2235                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2236                         continue;
2237 
2238                 /* Note: these are blocking operations */
2239                 drop_dquot_ref(sb, cnt);
2240                 invalidate_dquots(sb, cnt);
2241                 /*
2242                  * Now all dquots should be invalidated, all writes done so we
2243                  * should be only users of the info. No locks needed.
2244                  */
2245                 if (info_dirty(&dqopt->info[cnt]))
2246                         sb->dq_op->write_info(sb, cnt);
2247                 if (dqopt->ops[cnt]->free_file_info)
2248                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2249                 put_quota_format(dqopt->info[cnt].dqi_format);
2250                 dqopt->info[cnt].dqi_flags = 0;
2251                 dqopt->info[cnt].dqi_igrace = 0;
2252                 dqopt->info[cnt].dqi_bgrace = 0;
2253                 dqopt->ops[cnt] = NULL;
2254         }
2255 
2256         /* Skip syncing and setting flags if quota files are hidden */
2257         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2258                 goto put_inodes;
2259 
2260         /* Sync the superblock so that buffers with quota data are written to
2261          * disk (and so userspace sees correct data afterwards). */
2262         if (sb->s_op->sync_fs)
2263                 sb->s_op->sync_fs(sb, 1);
2264         sync_blockdev(sb->s_bdev);
2265         /* Now the quota files are just ordinary files and we can set the
2266          * inode flags back. Moreover we discard the pagecache so that
2267          * userspace sees the writes we did bypassing the pagecache. We
2268          * must also discard the blockdev buffers so that we see the
2269          * changes done by userspace on the next quotaon() */
2270         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2271                 if (!sb_has_quota_loaded(sb, cnt) && dqopt->files[cnt]) {
2272                         inode_lock(dqopt->files[cnt]);
2273                         truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
2274                         inode_unlock(dqopt->files[cnt]);
2275                 }
2276         if (sb->s_bdev)
2277                 invalidate_bdev(sb->s_bdev);
2278 put_inodes:
2279         /* We are done when suspending quotas */
2280         if (flags & DQUOT_SUSPENDED)
2281                 return 0;
2282 
2283         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2284                 if (!sb_has_quota_loaded(sb, cnt))
2285                         vfs_cleanup_quota_inode(sb, cnt);
2286         return 0;
2287 }
2288 EXPORT_SYMBOL(dquot_disable);
2289 
2290 int dquot_quota_off(struct super_block *sb, int type)
2291 {
2292         return dquot_disable(sb, type,
2293                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2294 }
2295 EXPORT_SYMBOL(dquot_quota_off);
2296 
2297 /*
2298  *      Turn quotas on on a device
2299  */
2300 
2301 static int vfs_setup_quota_inode(struct inode *inode, int type)
2302 {
2303         struct super_block *sb = inode->i_sb;
2304         struct quota_info *dqopt = sb_dqopt(sb);
2305 
2306         if (!S_ISREG(inode->i_mode))
2307                 return -EACCES;
2308         if (IS_RDONLY(inode))
2309                 return -EROFS;
2310         if (sb_has_quota_loaded(sb, type))
2311                 return -EBUSY;
2312 
2313         dqopt->files[type] = igrab(inode);
2314         if (!dqopt->files[type])
2315                 return -EIO;
2316         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2317                 /* We don't want quota and atime on quota files (deadlocks
2318                  * possible) Also nobody should write to the file - we use
2319                  * special IO operations which ignore the immutable bit. */
2320                 inode_lock(inode);
2321                 inode->i_flags |= S_NOQUOTA;
2322                 inode_unlock(inode);
2323                 /*
2324                  * When S_NOQUOTA is set, remove dquot references as no more
2325                  * references can be added
2326                  */
2327                 __dquot_drop(inode);
2328         }
2329         return 0;
2330 }
2331 
2332 int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,
2333         unsigned int flags)
2334 {
2335         struct quota_format_type *fmt = find_quota_format(format_id);
2336         struct quota_info *dqopt = sb_dqopt(sb);
2337         int error;
2338 
2339         /* Just unsuspend quotas? */
2340         BUG_ON(flags & DQUOT_SUSPENDED);
2341         /* s_umount should be held in exclusive mode */
2342         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2343                 up_read(&sb->s_umount);
2344 
2345         if (!fmt)
2346                 return -ESRCH;
2347         if (!sb->s_op->quota_write || !sb->s_op->quota_read ||
2348             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2349                 error = -EINVAL;
2350                 goto out_fmt;
2351         }
2352         /* Filesystems outside of init_user_ns not yet supported */
2353         if (sb->s_user_ns != &init_user_ns) {
2354                 error = -EINVAL;
2355                 goto out_fmt;
2356         }
2357         /* Usage always has to be set... */
2358         if (!(flags & DQUOT_USAGE_ENABLED)) {
2359                 error = -EINVAL;
2360                 goto out_fmt;
2361         }
2362         if (sb_has_quota_loaded(sb, type)) {
2363                 error = -EBUSY;
2364                 goto out_fmt;
2365         }
2366 
2367         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2368                 /* As we bypass the pagecache we must now flush all the
2369                  * dirty data and invalidate caches so that kernel sees
2370                  * changes from userspace. It is not enough to just flush
2371                  * the quota file since if blocksize < pagesize, invalidation
2372                  * of the cache could fail because of other unrelated dirty
2373                  * data */
2374                 sync_filesystem(sb);
2375                 invalidate_bdev(sb->s_bdev);
2376         }
2377 
2378         error = -EINVAL;
2379         if (!fmt->qf_ops->check_quota_file(sb, type))
2380                 goto out_fmt;
2381 
2382         dqopt->ops[type] = fmt->qf_ops;
2383         dqopt->info[type].dqi_format = fmt;
2384         dqopt->info[type].dqi_fmt_id = format_id;
2385         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2386         error = dqopt->ops[type]->read_file_info(sb, type);
2387         if (error < 0)
2388                 goto out_fmt;
2389         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2390                 spin_lock(&dq_data_lock);
2391                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2392                 spin_unlock(&dq_data_lock);
2393         }
2394         spin_lock(&dq_state_lock);
2395         dqopt->flags |= dquot_state_flag(flags, type);
2396         spin_unlock(&dq_state_lock);
2397 
2398         error = add_dquot_ref(sb, type);
2399         if (error)
2400                 dquot_disable(sb, type, flags);
2401 
2402         return error;
2403 out_fmt:
2404         put_quota_format(fmt);
2405 
2406         return error;
2407 }
2408 EXPORT_SYMBOL(dquot_load_quota_sb);
2409 
2410 /*
2411  * More powerful function for turning on quotas on given quota inode allowing
2412  * setting of individual quota flags
2413  */
2414 int dquot_load_quota_inode(struct inode *inode, int type, int format_id,
2415         unsigned int flags)
2416 {
2417         int err;
2418 
2419         err = vfs_setup_quota_inode(inode, type);
2420         if (err < 0)
2421                 return err;
2422         err = dquot_load_quota_sb(inode->i_sb, type, format_id, flags);
2423         if (err < 0)
2424                 vfs_cleanup_quota_inode(inode->i_sb, type);
2425         return err;
2426 }
2427 EXPORT_SYMBOL(dquot_load_quota_inode);
2428 
2429 /* Reenable quotas on remount RW */
2430 int dquot_resume(struct super_block *sb, int type)
2431 {
2432         struct quota_info *dqopt = sb_dqopt(sb);
2433         int ret = 0, cnt;
2434         unsigned int flags;
2435 
2436         /* s_umount should be held in exclusive mode */
2437         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2438                 up_read(&sb->s_umount);
2439 
2440         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2441                 if (type != -1 && cnt != type)
2442                         continue;
2443                 if (!sb_has_quota_suspended(sb, cnt))
2444                         continue;
2445 
2446                 spin_lock(&dq_state_lock);
2447                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2448                                                         DQUOT_LIMITS_ENABLED,
2449                                                         cnt);
2450                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2451                 spin_unlock(&dq_state_lock);
2452 
2453                 flags = dquot_generic_flag(flags, cnt);
2454                 ret = dquot_load_quota_sb(sb, cnt, dqopt->info[cnt].dqi_fmt_id,
2455                                           flags);
2456                 if (ret < 0)
2457                         vfs_cleanup_quota_inode(sb, type);
2458         }
2459 
2460         return ret;
2461 }
2462 EXPORT_SYMBOL(dquot_resume);
2463 
2464 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2465                    const struct path *path)
2466 {
2467         int error = security_quota_on(path->dentry);
2468         if (error)
2469                 return error;
2470         /* Quota file not on the same filesystem? */
2471         if (path->dentry->d_sb != sb)
2472                 error = -EXDEV;
2473         else
2474                 error = dquot_load_quota_inode(d_inode(path->dentry), type,
2475                                              format_id, DQUOT_USAGE_ENABLED |
2476                                              DQUOT_LIMITS_ENABLED);
2477         return error;
2478 }
2479 EXPORT_SYMBOL(dquot_quota_on);
2480 
2481 /*
2482  * This function is used when filesystem needs to initialize quotas
2483  * during mount time.
2484  */
2485 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2486                 int format_id, int type)
2487 {
2488         struct dentry *dentry;
2489         int error;
2490 
2491         dentry = lookup_positive_unlocked(qf_name, sb->s_root, strlen(qf_name));
2492         if (IS_ERR(dentry))
2493                 return PTR_ERR(dentry);
2494 
2495         error = security_quota_on(dentry);
2496         if (!error)
2497                 error = dquot_load_quota_inode(d_inode(dentry), type, format_id,
2498                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2499 
2500         dput(dentry);
2501         return error;
2502 }
2503 EXPORT_SYMBOL(dquot_quota_on_mount);
2504 
2505 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2506 {
2507         int ret;
2508         int type;
2509         struct quota_info *dqopt = sb_dqopt(sb);
2510 
2511         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2512                 return -ENOSYS;
2513         /* Accounting cannot be turned on while fs is mounted */
2514         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2515         if (!flags)
2516                 return -EINVAL;
2517         for (type = 0; type < MAXQUOTAS; type++) {
2518                 if (!(flags & qtype_enforce_flag(type)))
2519                         continue;
2520                 /* Can't enforce without accounting */
2521                 if (!sb_has_quota_usage_enabled(sb, type)) {
2522                         ret = -EINVAL;
2523                         goto out_err;
2524                 }
2525                 if (sb_has_quota_limits_enabled(sb, type)) {
2526                         ret = -EBUSY;
2527                         goto out_err;
2528                 }
2529                 spin_lock(&dq_state_lock);
2530                 dqopt->flags |= dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2531                 spin_unlock(&dq_state_lock);
2532         }
2533         return 0;
2534 out_err:
2535         /* Backout enforcement enablement we already did */
2536         for (type--; type >= 0; type--)  {
2537                 if (flags & qtype_enforce_flag(type))
2538                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2539         }
2540         /* Error code translation for better compatibility with XFS */
2541         if (ret == -EBUSY)
2542                 ret = -EEXIST;
2543         return ret;
2544 }
2545 
2546 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2547 {
2548         int ret;
2549         int type;
2550         struct quota_info *dqopt = sb_dqopt(sb);
2551 
2552         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2553                 return -ENOSYS;
2554         /*
2555          * We don't support turning off accounting via quotactl. In principle
2556          * quota infrastructure can do this but filesystems don't expect
2557          * userspace to be able to do it.
2558          */
2559         if (flags &
2560                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2561                 return -EOPNOTSUPP;
2562 
2563         /* Filter out limits not enabled */
2564         for (type = 0; type < MAXQUOTAS; type++)
2565                 if (!sb_has_quota_limits_enabled(sb, type))
2566                         flags &= ~qtype_enforce_flag(type);
2567         /* Nothing left? */
2568         if (!flags)
2569                 return -EEXIST;
2570         for (type = 0; type < MAXQUOTAS; type++) {
2571                 if (flags & qtype_enforce_flag(type)) {
2572                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2573                         if (ret < 0)
2574                                 goto out_err;
2575                 }
2576         }
2577         return 0;
2578 out_err:
2579         /* Backout enforcement disabling we already did */
2580         for (type--; type >= 0; type--)  {
2581                 if (flags & qtype_enforce_flag(type)) {
2582                         spin_lock(&dq_state_lock);
2583                         dqopt->flags |=
2584                                 dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
2585                         spin_unlock(&dq_state_lock);
2586                 }
2587         }
2588         return ret;
2589 }
2590 
2591 /* Generic routine for getting common part of quota structure */
2592 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2593 {
2594         struct mem_dqblk *dm = &dquot->dq_dqb;
2595 
2596         memset(di, 0, sizeof(*di));
2597         spin_lock(&dquot->dq_dqb_lock);
2598         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2599         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2600         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2601         di->d_ino_softlimit = dm->dqb_isoftlimit;
2602         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2603         di->d_ino_count = dm->dqb_curinodes;
2604         di->d_spc_timer = dm->dqb_btime;
2605         di->d_ino_timer = dm->dqb_itime;
2606         spin_unlock(&dquot->dq_dqb_lock);
2607 }
2608 
2609 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2610                     struct qc_dqblk *di)
2611 {
2612         struct dquot *dquot;
2613 
2614         dquot = dqget(sb, qid);
2615         if (IS_ERR(dquot))
2616                 return PTR_ERR(dquot);
2617         do_get_dqblk(dquot, di);
2618         dqput(dquot);
2619 
2620         return 0;
2621 }
2622 EXPORT_SYMBOL(dquot_get_dqblk);
2623 
2624 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2625                          struct qc_dqblk *di)
2626 {
2627         struct dquot *dquot;
2628         int err;
2629 
2630         if (!sb->dq_op->get_next_id)
2631                 return -ENOSYS;
2632         err = sb->dq_op->get_next_id(sb, qid);
2633         if (err < 0)
2634                 return err;
2635         dquot = dqget(sb, *qid);
2636         if (IS_ERR(dquot))
2637                 return PTR_ERR(dquot);
2638         do_get_dqblk(dquot, di);
2639         dqput(dquot);
2640 
2641         return 0;
2642 }
2643 EXPORT_SYMBOL(dquot_get_next_dqblk);
2644 
2645 #define VFS_QC_MASK \
2646         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2647          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2648          QC_SPC_TIMER | QC_INO_TIMER)
2649 
2650 /* Generic routine for setting common part of quota structure */
2651 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2652 {
2653         struct mem_dqblk *dm = &dquot->dq_dqb;
2654         int check_blim = 0, check_ilim = 0;
2655         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2656 
2657         if (di->d_fieldmask & ~VFS_QC_MASK)
2658                 return -EINVAL;
2659 
2660         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2661              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2662             ((di->d_fieldmask & QC_SPC_HARD) &&
2663              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2664             ((di->d_fieldmask & QC_INO_SOFT) &&
2665              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2666             ((di->d_fieldmask & QC_INO_HARD) &&
2667              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2668                 return -ERANGE;
2669 
2670         spin_lock(&dquot->dq_dqb_lock);
2671         if (di->d_fieldmask & QC_SPACE) {
2672                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2673                 check_blim = 1;
2674                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2675         }
2676 
2677         if (di->d_fieldmask & QC_SPC_SOFT)
2678                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2679         if (di->d_fieldmask & QC_SPC_HARD)
2680                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2681         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2682                 check_blim = 1;
2683                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2684         }
2685 
2686         if (di->d_fieldmask & QC_INO_COUNT) {
2687                 dm->dqb_curinodes = di->d_ino_count;
2688                 check_ilim = 1;
2689                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2690         }
2691 
2692         if (di->d_fieldmask & QC_INO_SOFT)
2693                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2694         if (di->d_fieldmask & QC_INO_HARD)
2695                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2696         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2697                 check_ilim = 1;
2698                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2699         }
2700 
2701         if (di->d_fieldmask & QC_SPC_TIMER) {
2702                 dm->dqb_btime = di->d_spc_timer;
2703                 check_blim = 1;
2704                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2705         }
2706 
2707         if (di->d_fieldmask & QC_INO_TIMER) {
2708                 dm->dqb_itime = di->d_ino_timer;
2709                 check_ilim = 1;
2710                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2711         }
2712 
2713         if (check_blim) {
2714                 if (!dm->dqb_bsoftlimit ||
2715                     dm->dqb_curspace + dm->dqb_rsvspace <= dm->dqb_bsoftlimit) {
2716                         dm->dqb_btime = 0;
2717                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2718                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2719                         /* Set grace only if user hasn't provided his own... */
2720                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2721         }
2722         if (check_ilim) {
2723                 if (!dm->dqb_isoftlimit ||
2724                     dm->dqb_curinodes <= dm->dqb_isoftlimit) {
2725                         dm->dqb_itime = 0;
2726                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2727                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2728                         /* Set grace only if user hasn't provided his own... */
2729                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2730         }
2731         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2732             dm->dqb_isoftlimit)
2733                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2734         else
2735                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2736         spin_unlock(&dquot->dq_dqb_lock);
2737         mark_dquot_dirty(dquot);
2738 
2739         return 0;
2740 }
2741 
2742 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2743                   struct qc_dqblk *di)
2744 {
2745         struct dquot *dquot;
2746         int rc;
2747 
2748         dquot = dqget(sb, qid);
2749         if (IS_ERR(dquot)) {
2750                 rc = PTR_ERR(dquot);
2751                 goto out;
2752         }
2753         rc = do_set_dqblk(dquot, di);
2754         dqput(dquot);
2755 out:
2756         return rc;
2757 }
2758 EXPORT_SYMBOL(dquot_set_dqblk);
2759 
2760 /* Generic routine for getting common part of quota file information */
2761 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2762 {
2763         struct mem_dqinfo *mi;
2764         struct qc_type_state *tstate;
2765         struct quota_info *dqopt = sb_dqopt(sb);
2766         int type;
2767 
2768         memset(state, 0, sizeof(*state));
2769         for (type = 0; type < MAXQUOTAS; type++) {
2770                 if (!sb_has_quota_active(sb, type))
2771                         continue;
2772                 tstate = state->s_state + type;
2773                 mi = sb_dqopt(sb)->info + type;
2774                 tstate->flags = QCI_ACCT_ENABLED;
2775                 spin_lock(&dq_data_lock);
2776                 if (mi->dqi_flags & DQF_SYS_FILE)
2777                         tstate->flags |= QCI_SYSFILE;
2778                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2779                         tstate->flags |= QCI_ROOT_SQUASH;
2780                 if (sb_has_quota_limits_enabled(sb, type))
2781                         tstate->flags |= QCI_LIMITS_ENFORCED;
2782                 tstate->spc_timelimit = mi->dqi_bgrace;
2783                 tstate->ino_timelimit = mi->dqi_igrace;
2784                 if (dqopt->files[type]) {
2785                         tstate->ino = dqopt->files[type]->i_ino;
2786                         tstate->blocks = dqopt->files[type]->i_blocks;
2787                 }
2788                 tstate->nextents = 1;   /* We don't know... */
2789                 spin_unlock(&dq_data_lock);
2790         }
2791         return 0;
2792 }
2793 EXPORT_SYMBOL(dquot_get_state);
2794 
2795 /* Generic routine for setting common part of quota file information */
2796 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2797 {
2798         struct mem_dqinfo *mi;
2799         int err = 0;
2800 
2801         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2802             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2803                 return -EINVAL;
2804         if (!sb_has_quota_active(sb, type))
2805                 return -ESRCH;
2806         mi = sb_dqopt(sb)->info + type;
2807         if (ii->i_fieldmask & QC_FLAGS) {
2808                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2809                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2810                         return -EINVAL;
2811         }
2812         spin_lock(&dq_data_lock);
2813         if (ii->i_fieldmask & QC_SPC_TIMER)
2814                 mi->dqi_bgrace = ii->i_spc_timelimit;
2815         if (ii->i_fieldmask & QC_INO_TIMER)
2816                 mi->dqi_igrace = ii->i_ino_timelimit;
2817         if (ii->i_fieldmask & QC_FLAGS) {
2818                 if (ii->i_flags & QCI_ROOT_SQUASH)
2819                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2820                 else
2821                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2822         }
2823         spin_unlock(&dq_data_lock);
2824         mark_info_dirty(sb, type);
2825         /* Force write to disk */
2826         sb->dq_op->write_info(sb, type);
2827         return err;
2828 }
2829 EXPORT_SYMBOL(dquot_set_dqinfo);
2830 
2831 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2832         .quota_enable   = dquot_quota_enable,
2833         .quota_disable  = dquot_quota_disable,
2834         .quota_sync     = dquot_quota_sync,
2835         .get_state      = dquot_get_state,
2836         .set_info       = dquot_set_dqinfo,
2837         .get_dqblk      = dquot_get_dqblk,
2838         .get_nextdqblk  = dquot_get_next_dqblk,
2839         .set_dqblk      = dquot_set_dqblk
2840 };
2841 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2842 
2843 static int do_proc_dqstats(struct ctl_table *table, int write,
2844                      void __user *buffer, size_t *lenp, loff_t *ppos)
2845 {
2846         unsigned int type = (unsigned long *)table->data - dqstats.stat;
2847         s64 value = percpu_counter_sum(&dqstats.counter[type]);
2848 
2849         /* Filter negative values for non-monotonic counters */
2850         if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
2851                           type == DQST_FREE_DQUOTS))
2852                 value = 0;
2853 
2854         /* Update global table */
2855         dqstats.stat[type] = value;
2856         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
2857 }
2858 
2859 static struct ctl_table fs_dqstats_table[] = {
2860         {
2861                 .procname       = "lookups",
2862                 .data           = &dqstats.stat[DQST_LOOKUPS],
2863                 .maxlen         = sizeof(unsigned long),
2864                 .mode           = 0444,
2865                 .proc_handler   = do_proc_dqstats,
2866         },
2867         {
2868                 .procname       = "drops",
2869                 .data           = &dqstats.stat[DQST_DROPS],
2870                 .maxlen         = sizeof(unsigned long),
2871                 .mode           = 0444,
2872                 .proc_handler   = do_proc_dqstats,
2873         },
2874         {
2875                 .procname       = "reads",
2876                 .data           = &dqstats.stat[DQST_READS],
2877                 .maxlen         = sizeof(unsigned long),
2878                 .mode           = 0444,
2879                 .proc_handler   = do_proc_dqstats,
2880         },
2881         {
2882                 .procname       = "writes",
2883                 .data           = &dqstats.stat[DQST_WRITES],
2884                 .maxlen         = sizeof(unsigned long),
2885                 .mode           = 0444,
2886                 .proc_handler   = do_proc_dqstats,
2887         },
2888         {
2889                 .procname       = "cache_hits",
2890                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2891                 .maxlen         = sizeof(unsigned long),
2892                 .mode           = 0444,
2893                 .proc_handler   = do_proc_dqstats,
2894         },
2895         {
2896                 .procname       = "allocated_dquots",
2897                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2898                 .maxlen         = sizeof(unsigned long),
2899                 .mode           = 0444,
2900                 .proc_handler   = do_proc_dqstats,
2901         },
2902         {
2903                 .procname       = "free_dquots",
2904                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2905                 .maxlen         = sizeof(unsigned long),
2906                 .mode           = 0444,
2907                 .proc_handler   = do_proc_dqstats,
2908         },
2909         {
2910                 .procname       = "syncs",
2911                 .data           = &dqstats.stat[DQST_SYNCS],
2912                 .maxlen         = sizeof(unsigned long),
2913                 .mode           = 0444,
2914                 .proc_handler   = do_proc_dqstats,
2915         },
2916 #ifdef CONFIG_PRINT_QUOTA_WARNING
2917         {
2918                 .procname       = "warnings",
2919                 .data           = &flag_print_warnings,
2920                 .maxlen         = sizeof(int),
2921                 .mode           = 0644,
2922                 .proc_handler   = proc_dointvec,
2923         },
2924 #endif
2925         { },
2926 };
2927 
2928 static struct ctl_table fs_table[] = {
2929         {
2930                 .procname       = "quota",
2931                 .mode           = 0555,
2932                 .child          = fs_dqstats_table,
2933         },
2934         { },
2935 };
2936 
2937 static struct ctl_table sys_table[] = {
2938         {
2939                 .procname       = "fs",
2940                 .mode           = 0555,
2941                 .child          = fs_table,
2942         },
2943         { },
2944 };
2945 
2946 static int __init dquot_init(void)
2947 {
2948         int i, ret;
2949         unsigned long nr_hash, order;
2950 
2951         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2952 
2953         register_sysctl_table(sys_table);
2954 
2955         dquot_cachep = kmem_cache_create("dquot",
2956                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2957                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2958                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2959                         NULL);
2960 
2961         order = 0;
2962         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_KERNEL, order);
2963         if (!dquot_hash)
2964                 panic("Cannot create dquot hash table");
2965 
2966         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2967                 ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
2968                 if (ret)
2969                         panic("Cannot create dquot stat counters");
2970         }
2971 
2972         /* Find power-of-two hlist_heads which can fit into allocation */
2973         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2974         dq_hash_bits = ilog2(nr_hash);
2975 
2976         nr_hash = 1UL << dq_hash_bits;
2977         dq_hash_mask = nr_hash - 1;
2978         for (i = 0; i < nr_hash; i++)
2979                 INIT_HLIST_HEAD(dquot_hash + i);
2980 
2981         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
2982                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
2983 
2984         if (register_shrinker(&dqcache_shrinker))
2985                 panic("Cannot register dquot shrinker");
2986 
2987         return 0;
2988 }
2989 fs_initcall(dquot_init);
2990 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp