fs/quota/dquot.c

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This source file includes following definitions.
__quota_error
register_quota_format
unregister_quota_format
find_quota_format
put_quota_format
hashfn
insert_dquot_hash
remove_dquot_hash
find_dquot
put_dquot_last
remove_free_dquot
put_inuse
remove_inuse
wait_on_dquot
dquot_dirty
mark_dquot_dirty
dquot_mark_dquot_dirty
mark_all_dquot_dirty
dqput_all
clear_dquot_dirty
mark_info_dirty
dquot_acquire
dquot_commit
dquot_release
dquot_destroy
do_destroy_dquot
invalidate_dquots
dquot_scan_active
dquot_writeback_dquots
dquot_quota_sync
dqcache_shrink_scan
dqcache_shrink_count
dqput
dquot_alloc
get_empty_dquot
dqget
i_dquot
dqinit_needed
add_dquot_ref
remove_inode_dquot_ref
put_dquot_list
remove_dquot_ref
drop_dquot_ref
dquot_free_reserved_space
dquot_decr_inodes
dquot_decr_space
warning_issued
need_print_warning
print_warning
prepare_warning
flush_warnings
ignore_hardlimit
dquot_add_inodes
dquot_add_space
info_idq_free
info_bdq_free
dquot_active
__dquot_initialize
dquot_initialize
dquot_initialize_needed
__dquot_drop
dquot_drop
inode_reserved_space
__inode_get_rsv_space
inode_get_rsv_space
__dquot_alloc_space
dquot_alloc_inode
dquot_claim_space_nodirty
dquot_reclaim_space_nodirty
__dquot_free_space
dquot_free_inode
__dquot_transfer
dquot_transfer
dquot_commit_info
dquot_get_next_id
dquot_file_open
dquot_disable
dquot_quota_off
vfs_load_quota_inode
dquot_resume
dquot_quota_on
dquot_enable
dquot_quota_on_mount
dquot_quota_enable
dquot_quota_disable
do_get_dqblk
dquot_get_dqblk
dquot_get_next_dqblk
do_set_dqblk
dquot_set_dqblk
dquot_get_state
dquot_set_dqinfo
do_proc_dqstats
dquot_init
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Implementation of the diskquota system for the LINUX operating system. QUOTA
   4  * is implemented using the BSD system call interface as the means of
   5  * communication with the user level. This file contains the generic routines
   6  * called by the different filesystems on allocation of an inode or block.
   7  * These routines take care of the administration needed to have a consistent
   8  * diskquota tracking system. The ideas of both user and group quotas are based
   9  * on the Melbourne quota system as used on BSD derived systems. The internal
  10  * implementation is based on one of the several variants of the LINUX
  11  * inode-subsystem with added complexity of the diskquota system.
  12  *
  13  * Author:      Marco van Wieringen <mvw@planets.elm.net>
  14  *
  15  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
  16  *
  17  *              Revised list management to avoid races
  18  *              -- Bill Hawes, <whawes@star.net>, 9/98
  19  *
  20  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
  21  *              As the consequence the locking was moved from dquot_decr_...(),
  22  *              dquot_incr_...() to calling functions.
  23  *              invalidate_dquots() now writes modified dquots.
  24  *              Serialized quota_off() and quota_on() for mount point.
  25  *              Fixed a few bugs in grow_dquots().
  26  *              Fixed deadlock in write_dquot() - we no longer account quotas on
  27  *              quota files
  28  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
  29  *              add_dquot_ref() restarts after blocking
  30  *              Added check for bogus uid and fixed check for group in quotactl.
  31  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
  32  *
  33  *              Used struct list_head instead of own list struct
  34  *              Invalidation of referenced dquots is no longer possible
  35  *              Improved free_dquots list management
  36  *              Quota and i_blocks are now updated in one place to avoid races
  37  *              Warnings are now delayed so we won't block in critical section
  38  *              Write updated not to require dquot lock
  39  *              Jan Kara, <jack@suse.cz>, 9/2000
  40  *
  41  *              Added dynamic quota structure allocation
  42  *              Jan Kara <jack@suse.cz> 12/2000
  43  *
  44  *              Rewritten quota interface. Implemented new quota format and
  45  *              formats registering.
  46  *              Jan Kara, <jack@suse.cz>, 2001,2002
  47  *
  48  *              New SMP locking.
  49  *              Jan Kara, <jack@suse.cz>, 10/2002
  50  *
  51  *              Added journalled quota support, fix lock inversion problems
  52  *              Jan Kara, <jack@suse.cz>, 2003,2004
  53  *
  54  * (C) Copyright 1994 - 1997 Marco van Wieringen
  55  */
  56 
  57 #include <linux/errno.h>
  58 #include <linux/kernel.h>
  59 #include <linux/fs.h>
  60 #include <linux/mount.h>
  61 #include <linux/mm.h>
  62 #include <linux/time.h>
  63 #include <linux/types.h>
  64 #include <linux/string.h>
  65 #include <linux/fcntl.h>
  66 #include <linux/stat.h>
  67 #include <linux/tty.h>
  68 #include <linux/file.h>
  69 #include <linux/slab.h>
  70 #include <linux/sysctl.h>
  71 #include <linux/init.h>
  72 #include <linux/module.h>
  73 #include <linux/proc_fs.h>
  74 #include <linux/security.h>
  75 #include <linux/sched.h>
  76 #include <linux/cred.h>
  77 #include <linux/kmod.h>
  78 #include <linux/namei.h>
  79 #include <linux/capability.h>
  80 #include <linux/quotaops.h>
  81 #include "../internal.h" /* ugh */
  82 
  83 #include <linux/uaccess.h>
  84 
  85 /*
  86  * There are five quota SMP locks:
  87  * * dq_list_lock protects all lists with quotas and quota formats.
  88  * * dquot->dq_dqb_lock protects data from dq_dqb
  89  * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
  90  *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
  91  *   dquot_transfer() can stabilize amount it transfers
  92  * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
  93  *   pointers in the inode
  94  * * dq_state_lock protects modifications of quota state (on quotaon and
  95  *   quotaoff) and readers who care about latest values take it as well.
  96  *
  97  * The spinlock ordering is hence:
  98  *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
  99  *   dq_list_lock > dq_state_lock
 100  *
 101  * Note that some things (eg. sb pointer, type, id) doesn't change during
 102  * the life of the dquot structure and so needn't to be protected by a lock
 103  *
 104  * Operation accessing dquots via inode pointers are protected by dquot_srcu.
 105  * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
 106  * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
 107  * inode and before dropping dquot references to avoid use of dquots after
 108  * they are freed. dq_data_lock is used to serialize the pointer setting and
 109  * clearing operations.
 110  * Special care needs to be taken about S_NOQUOTA inode flag (marking that
 111  * inode is a quota file). Functions adding pointers from inode to dquots have
 112  * to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
 113  * have to do all pointer modifications before dropping dq_data_lock. This makes
 114  * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
 115  * then drops all pointers to dquots from an inode.
 116  *
 117  * Each dquot has its dq_lock mutex.  Dquot is locked when it is being read to
 118  * memory (or space for it is being allocated) on the first dqget(), when it is
 119  * being written out, and when it is being released on the last dqput(). The
 120  * allocation and release operations are serialized by the dq_lock and by
 121  * checking the use count in dquot_release().
 122  *
 123  * Lock ordering (including related VFS locks) is the following:
 124  *   s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
 125  */
 126 
 127 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
 128 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
 129 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
 130 EXPORT_SYMBOL(dq_data_lock);
 131 DEFINE_STATIC_SRCU(dquot_srcu);
 132 
 133 static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
 134 
 135 void __quota_error(struct super_block *sb, const char *func,
 136                    const char *fmt, ...)
 137 {
 138         if (printk_ratelimit()) {
 139                 va_list args;
 140                 struct va_format vaf;
 141 
 142                 va_start(args, fmt);
 143 
 144                 vaf.fmt = fmt;
 145                 vaf.va = &args;
 146 
 147                 printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
 148                        sb->s_id, func, &vaf);
 149 
 150                 va_end(args);
 151         }
 152 }
 153 EXPORT_SYMBOL(__quota_error);
 154 
 155 #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
 156 static char *quotatypes[] = INITQFNAMES;
 157 #endif
 158 static struct quota_format_type *quota_formats; /* List of registered formats */
 159 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
 160 
 161 /* SLAB cache for dquot structures */
 162 static struct kmem_cache *dquot_cachep;
 163 
 164 int register_quota_format(struct quota_format_type *fmt)
 165 {
 166         spin_lock(&dq_list_lock);
 167         fmt->qf_next = quota_formats;
 168         quota_formats = fmt;
 169         spin_unlock(&dq_list_lock);
 170         return 0;
 171 }
 172 EXPORT_SYMBOL(register_quota_format);
 173 
 174 void unregister_quota_format(struct quota_format_type *fmt)
 175 {
 176         struct quota_format_type **actqf;
 177 
 178         spin_lock(&dq_list_lock);
 179         for (actqf = &quota_formats; *actqf && *actqf != fmt;
 180              actqf = &(*actqf)->qf_next)
 181                 ;
 182         if (*actqf)
 183                 *actqf = (*actqf)->qf_next;
 184         spin_unlock(&dq_list_lock);
 185 }
 186 EXPORT_SYMBOL(unregister_quota_format);
 187 
 188 static struct quota_format_type *find_quota_format(int id)
 189 {
 190         struct quota_format_type *actqf;
 191 
 192         spin_lock(&dq_list_lock);
 193         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
 194              actqf = actqf->qf_next)
 195                 ;
 196         if (!actqf || !try_module_get(actqf->qf_owner)) {
 197                 int qm;
 198 
 199                 spin_unlock(&dq_list_lock);
 200 
 201                 for (qm = 0; module_names[qm].qm_fmt_id &&
 202                              module_names[qm].qm_fmt_id != id; qm++)
 203                         ;
 204                 if (!module_names[qm].qm_fmt_id ||
 205                     request_module(module_names[qm].qm_mod_name))
 206                         return NULL;
 207 
 208                 spin_lock(&dq_list_lock);
 209                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id;
 210                      actqf = actqf->qf_next)
 211                         ;
 212                 if (actqf && !try_module_get(actqf->qf_owner))
 213                         actqf = NULL;
 214         }
 215         spin_unlock(&dq_list_lock);
 216         return actqf;
 217 }
 218 
 219 static void put_quota_format(struct quota_format_type *fmt)
 220 {
 221         module_put(fmt->qf_owner);
 222 }
 223 
 224 /*
 225  * Dquot List Management:
 226  * The quota code uses four lists for dquot management: the inuse_list,
 227  * free_dquots, dqi_dirty_list, and dquot_hash[] array. A single dquot
 228  * structure may be on some of those lists, depending on its current state.
 229  *
 230  * All dquots are placed to the end of inuse_list when first created, and this
 231  * list is used for invalidate operation, which must look at every dquot.
 232  *
 233  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 234  * and this list is searched whenever we need an available dquot.  Dquots are
 235  * removed from the list as soon as they are used again, and
 236  * dqstats.free_dquots gives the number of dquots on the list. When
 237  * dquot is invalidated it's completely released from memory.
 238  *
 239  * Dirty dquots are added to the dqi_dirty_list of quota_info when mark
 240  * dirtied, and this list is searched when writing dirty dquots back to
 241  * quota file. Note that some filesystems do dirty dquot tracking on their
 242  * own (e.g. in a journal) and thus don't use dqi_dirty_list.
 243  *
 244  * Dquots with a specific identity (device, type and id) are placed on
 245  * one of the dquot_hash[] hash chains. The provides an efficient search
 246  * mechanism to locate a specific dquot.
 247  */
 248 
 249 static LIST_HEAD(inuse_list);
 250 static LIST_HEAD(free_dquots);
 251 static unsigned int dq_hash_bits, dq_hash_mask;
 252 static struct hlist_head *dquot_hash;
 253 
 254 struct dqstats dqstats;
 255 EXPORT_SYMBOL(dqstats);
 256 
 257 static qsize_t inode_get_rsv_space(struct inode *inode);
 258 static qsize_t __inode_get_rsv_space(struct inode *inode);
 259 static int __dquot_initialize(struct inode *inode, int type);
 260 
 261 static inline unsigned int
 262 hashfn(const struct super_block *sb, struct kqid qid)
 263 {
 264         unsigned int id = from_kqid(&init_user_ns, qid);
 265         int type = qid.type;
 266         unsigned long tmp;
 267 
 268         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
 269         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
 270 }
 271 
 272 /*
 273  * Following list functions expect dq_list_lock to be held
 274  */
 275 static inline void insert_dquot_hash(struct dquot *dquot)
 276 {
 277         struct hlist_head *head;
 278         head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
 279         hlist_add_head(&dquot->dq_hash, head);
 280 }
 281 
 282 static inline void remove_dquot_hash(struct dquot *dquot)
 283 {
 284         hlist_del_init(&dquot->dq_hash);
 285 }
 286 
 287 static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
 288                                 struct kqid qid)
 289 {
 290         struct hlist_node *node;
 291         struct dquot *dquot;
 292 
 293         hlist_for_each (node, dquot_hash+hashent) {
 294                 dquot = hlist_entry(node, struct dquot, dq_hash);
 295                 if (dquot->dq_sb == sb && qid_eq(dquot->dq_id, qid))
 296                         return dquot;
 297         }
 298         return NULL;
 299 }
 300 
 301 /* Add a dquot to the tail of the free list */
 302 static inline void put_dquot_last(struct dquot *dquot)
 303 {
 304         list_add_tail(&dquot->dq_free, &free_dquots);
 305         dqstats_inc(DQST_FREE_DQUOTS);
 306 }
 307 
 308 static inline void remove_free_dquot(struct dquot *dquot)
 309 {
 310         if (list_empty(&dquot->dq_free))
 311                 return;
 312         list_del_init(&dquot->dq_free);
 313         dqstats_dec(DQST_FREE_DQUOTS);
 314 }
 315 
 316 static inline void put_inuse(struct dquot *dquot)
 317 {
 318         /* We add to the back of inuse list so we don't have to restart
 319          * when traversing this list and we block */
 320         list_add_tail(&dquot->dq_inuse, &inuse_list);
 321         dqstats_inc(DQST_ALLOC_DQUOTS);
 322 }
 323 
 324 static inline void remove_inuse(struct dquot *dquot)
 325 {
 326         dqstats_dec(DQST_ALLOC_DQUOTS);
 327         list_del(&dquot->dq_inuse);
 328 }
 329 /*
 330  * End of list functions needing dq_list_lock
 331  */
 332 
 333 static void wait_on_dquot(struct dquot *dquot)
 334 {
 335         mutex_lock(&dquot->dq_lock);
 336         mutex_unlock(&dquot->dq_lock);
 337 }
 338 
 339 static inline int dquot_dirty(struct dquot *dquot)
 340 {
 341         return test_bit(DQ_MOD_B, &dquot->dq_flags);
 342 }
 343 
 344 static inline int mark_dquot_dirty(struct dquot *dquot)
 345 {
 346         return dquot->dq_sb->dq_op->mark_dirty(dquot);
 347 }
 348 
 349 /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
 350 int dquot_mark_dquot_dirty(struct dquot *dquot)
 351 {
 352         int ret = 1;
 353 
 354         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
 355                 return 0;
 356 
 357         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
 358                 return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
 359 
 360         /* If quota is dirty already, we don't have to acquire dq_list_lock */
 361         if (test_bit(DQ_MOD_B, &dquot->dq_flags))
 362                 return 1;
 363 
 364         spin_lock(&dq_list_lock);
 365         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) {
 366                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
 367                                 info[dquot->dq_id.type].dqi_dirty_list);
 368                 ret = 0;
 369         }
 370         spin_unlock(&dq_list_lock);
 371         return ret;
 372 }
 373 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
 374 
 375 /* Dirtify all the dquots - this can block when journalling */
 376 static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
 377 {
 378         int ret, err, cnt;
 379 
 380         ret = err = 0;
 381         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 382                 if (dquot[cnt])
 383                         /* Even in case of error we have to continue */
 384                         ret = mark_dquot_dirty(dquot[cnt]);
 385                 if (!err)
 386                         err = ret;
 387         }
 388         return err;
 389 }
 390 
 391 static inline void dqput_all(struct dquot **dquot)
 392 {
 393         unsigned int cnt;
 394 
 395         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 396                 dqput(dquot[cnt]);
 397 }
 398 
 399 static inline int clear_dquot_dirty(struct dquot *dquot)
 400 {
 401         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
 402                 return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
 403 
 404         spin_lock(&dq_list_lock);
 405         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
 406                 spin_unlock(&dq_list_lock);
 407                 return 0;
 408         }
 409         list_del_init(&dquot->dq_dirty);
 410         spin_unlock(&dq_list_lock);
 411         return 1;
 412 }
 413 
 414 void mark_info_dirty(struct super_block *sb, int type)
 415 {
 416         spin_lock(&dq_data_lock);
 417         sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
 418         spin_unlock(&dq_data_lock);
 419 }
 420 EXPORT_SYMBOL(mark_info_dirty);
 421 
 422 /*
 423  *      Read dquot from disk and alloc space for it
 424  */
 425 
 426 int dquot_acquire(struct dquot *dquot)
 427 {
 428         int ret = 0, ret2 = 0;
 429         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 430 
 431         mutex_lock(&dquot->dq_lock);
 432         if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
 433                 ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
 434                 if (ret < 0)
 435                         goto out_iolock;
 436         }
 437         /* Make sure flags update is visible after dquot has been filled */
 438         smp_mb__before_atomic();
 439         set_bit(DQ_READ_B, &dquot->dq_flags);
 440         /* Instantiate dquot if needed */
 441         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
 442                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
 443                 /* Write the info if needed */
 444                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
 445                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
 446                                         dquot->dq_sb, dquot->dq_id.type);
 447                 }
 448                 if (ret < 0)
 449                         goto out_iolock;
 450                 if (ret2 < 0) {
 451                         ret = ret2;
 452                         goto out_iolock;
 453                 }
 454         }
 455         /*
 456          * Make sure flags update is visible after on-disk struct has been
 457          * allocated. Paired with smp_rmb() in dqget().
 458          */
 459         smp_mb__before_atomic();
 460         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 461 out_iolock:
 462         mutex_unlock(&dquot->dq_lock);
 463         return ret;
 464 }
 465 EXPORT_SYMBOL(dquot_acquire);
 466 
 467 /*
 468  *      Write dquot to disk
 469  */
 470 int dquot_commit(struct dquot *dquot)
 471 {
 472         int ret = 0;
 473         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 474 
 475         mutex_lock(&dquot->dq_lock);
 476         if (!clear_dquot_dirty(dquot))
 477                 goto out_lock;
 478         /* Inactive dquot can be only if there was error during read/init
 479          * => we have better not writing it */
 480         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
 481                 ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot);
 482         else
 483                 ret = -EIO;
 484 out_lock:
 485         mutex_unlock(&dquot->dq_lock);
 486         return ret;
 487 }
 488 EXPORT_SYMBOL(dquot_commit);
 489 
 490 /*
 491  *      Release dquot
 492  */
 493 int dquot_release(struct dquot *dquot)
 494 {
 495         int ret = 0, ret2 = 0;
 496         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 497 
 498         mutex_lock(&dquot->dq_lock);
 499         /* Check whether we are not racing with some other dqget() */
 500         if (dquot_is_busy(dquot))
 501                 goto out_dqlock;
 502         if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
 503                 ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
 504                 /* Write the info */
 505                 if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
 506                         ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
 507                                                 dquot->dq_sb, dquot->dq_id.type);
 508                 }
 509                 if (ret >= 0)
 510                         ret = ret2;
 511         }
 512         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 513 out_dqlock:
 514         mutex_unlock(&dquot->dq_lock);
 515         return ret;
 516 }
 517 EXPORT_SYMBOL(dquot_release);
 518 
 519 void dquot_destroy(struct dquot *dquot)
 520 {
 521         kmem_cache_free(dquot_cachep, dquot);
 522 }
 523 EXPORT_SYMBOL(dquot_destroy);
 524 
 525 static inline void do_destroy_dquot(struct dquot *dquot)
 526 {
 527         dquot->dq_sb->dq_op->destroy_dquot(dquot);
 528 }
 529 
 530 /* Invalidate all dquots on the list. Note that this function is called after
 531  * quota is disabled and pointers from inodes removed so there cannot be new
 532  * quota users. There can still be some users of quotas due to inodes being
 533  * just deleted or pruned by prune_icache() (those are not attached to any
 534  * list) or parallel quotactl call. We have to wait for such users.
 535  */
 536 static void invalidate_dquots(struct super_block *sb, int type)
 537 {
 538         struct dquot *dquot, *tmp;
 539 
 540 restart:
 541         spin_lock(&dq_list_lock);
 542         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
 543                 if (dquot->dq_sb != sb)
 544                         continue;
 545                 if (dquot->dq_id.type != type)
 546                         continue;
 547                 /* Wait for dquot users */
 548                 if (atomic_read(&dquot->dq_count)) {
 549                         dqgrab(dquot);
 550                         spin_unlock(&dq_list_lock);
 551                         /*
 552                          * Once dqput() wakes us up, we know it's time to free
 553                          * the dquot.
 554                          * IMPORTANT: we rely on the fact that there is always
 555                          * at most one process waiting for dquot to free.
 556                          * Otherwise dq_count would be > 1 and we would never
 557                          * wake up.
 558                          */
 559                         wait_event(dquot_ref_wq,
 560                                    atomic_read(&dquot->dq_count) == 1);
 561                         dqput(dquot);
 562                         /* At this moment dquot() need not exist (it could be
 563                          * reclaimed by prune_dqcache(). Hence we must
 564                          * restart. */
 565                         goto restart;
 566                 }
 567                 /*
 568                  * Quota now has no users and it has been written on last
 569                  * dqput()
 570                  */
 571                 remove_dquot_hash(dquot);
 572                 remove_free_dquot(dquot);
 573                 remove_inuse(dquot);
 574                 do_destroy_dquot(dquot);
 575         }
 576         spin_unlock(&dq_list_lock);
 577 }
 578 
 579 /* Call callback for every active dquot on given filesystem */
 580 int dquot_scan_active(struct super_block *sb,
 581                       int (*fn)(struct dquot *dquot, unsigned long priv),
 582                       unsigned long priv)
 583 {
 584         struct dquot *dquot, *old_dquot = NULL;
 585         int ret = 0;
 586 
 587         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
 588 
 589         spin_lock(&dq_list_lock);
 590         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
 591                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
 592                         continue;
 593                 if (dquot->dq_sb != sb)
 594                         continue;
 595                 /* Now we have active dquot so we can just increase use count */
 596                 atomic_inc(&dquot->dq_count);
 597                 spin_unlock(&dq_list_lock);
 598                 dqstats_inc(DQST_LOOKUPS);
 599                 dqput(old_dquot);
 600                 old_dquot = dquot;
 601                 /*
 602                  * ->release_dquot() can be racing with us. Our reference
 603                  * protects us from new calls to it so just wait for any
 604                  * outstanding call and recheck the DQ_ACTIVE_B after that.
 605                  */
 606                 wait_on_dquot(dquot);
 607                 if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 608                         ret = fn(dquot, priv);
 609                         if (ret < 0)
 610                                 goto out;
 611                 }
 612                 spin_lock(&dq_list_lock);
 613                 /* We are safe to continue now because our dquot could not
 614                  * be moved out of the inuse list while we hold the reference */
 615         }
 616         spin_unlock(&dq_list_lock);
 617 out:
 618         dqput(old_dquot);
 619         return ret;
 620 }
 621 EXPORT_SYMBOL(dquot_scan_active);
 622 
 623 /* Write all dquot structures to quota files */
 624 int dquot_writeback_dquots(struct super_block *sb, int type)
 625 {
 626         struct list_head dirty;
 627         struct dquot *dquot;
 628         struct quota_info *dqopt = sb_dqopt(sb);
 629         int cnt;
 630         int err, ret = 0;
 631 
 632         WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
 633 
 634         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 635                 if (type != -1 && cnt != type)
 636                         continue;
 637                 if (!sb_has_quota_active(sb, cnt))
 638                         continue;
 639                 spin_lock(&dq_list_lock);
 640                 /* Move list away to avoid livelock. */
 641                 list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty);
 642                 while (!list_empty(&dirty)) {
 643                         dquot = list_first_entry(&dirty, struct dquot,
 644                                                  dq_dirty);
 645 
 646                         WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
 647 
 648                         /* Now we have active dquot from which someone is
 649                          * holding reference so we can safely just increase
 650                          * use count */
 651                         dqgrab(dquot);
 652                         spin_unlock(&dq_list_lock);
 653                         dqstats_inc(DQST_LOOKUPS);
 654                         err = sb->dq_op->write_dquot(dquot);
 655                         if (err) {
 656                                 /*
 657                                  * Clear dirty bit anyway to avoid infinite
 658                                  * loop here.
 659                                  */
 660                                 clear_dquot_dirty(dquot);
 661                                 if (!ret)
 662                                         ret = err;
 663                         }
 664                         dqput(dquot);
 665                         spin_lock(&dq_list_lock);
 666                 }
 667                 spin_unlock(&dq_list_lock);
 668         }
 669 
 670         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 671                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
 672                     && info_dirty(&dqopt->info[cnt]))
 673                         sb->dq_op->write_info(sb, cnt);
 674         dqstats_inc(DQST_SYNCS);
 675 
 676         return ret;
 677 }
 678 EXPORT_SYMBOL(dquot_writeback_dquots);
 679 
 680 /* Write all dquot structures to disk and make them visible from userspace */
 681 int dquot_quota_sync(struct super_block *sb, int type)
 682 {
 683         struct quota_info *dqopt = sb_dqopt(sb);
 684         int cnt;
 685         int ret;
 686 
 687         ret = dquot_writeback_dquots(sb, type);
 688         if (ret)
 689                 return ret;
 690         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
 691                 return 0;
 692 
 693         /* This is not very clever (and fast) but currently I don't know about
 694          * any other simple way of getting quota data to disk and we must get
 695          * them there for userspace to be visible... */
 696         if (sb->s_op->sync_fs)
 697                 sb->s_op->sync_fs(sb, 1);
 698         sync_blockdev(sb->s_bdev);
 699 
 700         /*
 701          * Now when everything is written we can discard the pagecache so
 702          * that userspace sees the changes.
 703          */
 704         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 705                 if (type != -1 && cnt != type)
 706                         continue;
 707                 if (!sb_has_quota_active(sb, cnt))
 708                         continue;
 709                 inode_lock(dqopt->files[cnt]);
 710                 truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
 711                 inode_unlock(dqopt->files[cnt]);
 712         }
 713 
 714         return 0;
 715 }
 716 EXPORT_SYMBOL(dquot_quota_sync);
 717 
 718 static unsigned long
 719 dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 720 {
 721         struct dquot *dquot;
 722         unsigned long freed = 0;
 723 
 724         spin_lock(&dq_list_lock);
 725         while (!list_empty(&free_dquots) && sc->nr_to_scan) {
 726                 dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
 727                 remove_dquot_hash(dquot);
 728                 remove_free_dquot(dquot);
 729                 remove_inuse(dquot);
 730                 do_destroy_dquot(dquot);
 731                 sc->nr_to_scan--;
 732                 freed++;
 733         }
 734         spin_unlock(&dq_list_lock);
 735         return freed;
 736 }
 737 
 738 static unsigned long
 739 dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 740 {
 741         return vfs_pressure_ratio(
 742         percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
 743 }
 744 
 745 static struct shrinker dqcache_shrinker = {
 746         .count_objects = dqcache_shrink_count,
 747         .scan_objects = dqcache_shrink_scan,
 748         .seeks = DEFAULT_SEEKS,
 749 };
 750 
 751 /*
 752  * Put reference to dquot
 753  */
 754 void dqput(struct dquot *dquot)
 755 {
 756         int ret;
 757 
 758         if (!dquot)
 759                 return;
 760 #ifdef CONFIG_QUOTA_DEBUG
 761         if (!atomic_read(&dquot->dq_count)) {
 762                 quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
 763                             quotatypes[dquot->dq_id.type],
 764                             from_kqid(&init_user_ns, dquot->dq_id));
 765                 BUG();
 766         }
 767 #endif
 768         dqstats_inc(DQST_DROPS);
 769 we_slept:
 770         spin_lock(&dq_list_lock);
 771         if (atomic_read(&dquot->dq_count) > 1) {
 772                 /* We have more than one user... nothing to do */
 773                 atomic_dec(&dquot->dq_count);
 774                 /* Releasing dquot during quotaoff phase? */
 775                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_id.type) &&
 776                     atomic_read(&dquot->dq_count) == 1)
 777                         wake_up(&dquot_ref_wq);
 778                 spin_unlock(&dq_list_lock);
 779                 return;
 780         }
 781         /* Need to release dquot? */
 782         if (dquot_dirty(dquot)) {
 783                 spin_unlock(&dq_list_lock);
 784                 /* Commit dquot before releasing */
 785                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
 786                 if (ret < 0) {
 787                         quota_error(dquot->dq_sb, "Can't write quota structure"
 788                                     " (error %d). Quota may get out of sync!",
 789                                     ret);
 790                         /*
 791                          * We clear dirty bit anyway, so that we avoid
 792                          * infinite loop here
 793                          */
 794                         clear_dquot_dirty(dquot);
 795                 }
 796                 goto we_slept;
 797         }
 798         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 799                 spin_unlock(&dq_list_lock);
 800                 dquot->dq_sb->dq_op->release_dquot(dquot);
 801                 goto we_slept;
 802         }
 803         atomic_dec(&dquot->dq_count);
 804 #ifdef CONFIG_QUOTA_DEBUG
 805         /* sanity check */
 806         BUG_ON(!list_empty(&dquot->dq_free));
 807 #endif
 808         put_dquot_last(dquot);
 809         spin_unlock(&dq_list_lock);
 810 }
 811 EXPORT_SYMBOL(dqput);
 812 
 813 struct dquot *dquot_alloc(struct super_block *sb, int type)
 814 {
 815         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
 816 }
 817 EXPORT_SYMBOL(dquot_alloc);
 818 
 819 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 820 {
 821         struct dquot *dquot;
 822 
 823         dquot = sb->dq_op->alloc_dquot(sb, type);
 824         if(!dquot)
 825                 return NULL;
 826 
 827         mutex_init(&dquot->dq_lock);
 828         INIT_LIST_HEAD(&dquot->dq_free);
 829         INIT_LIST_HEAD(&dquot->dq_inuse);
 830         INIT_HLIST_NODE(&dquot->dq_hash);
 831         INIT_LIST_HEAD(&dquot->dq_dirty);
 832         dquot->dq_sb = sb;
 833         dquot->dq_id = make_kqid_invalid(type);
 834         atomic_set(&dquot->dq_count, 1);
 835         spin_lock_init(&dquot->dq_dqb_lock);
 836 
 837         return dquot;
 838 }
 839 
 840 /*
 841  * Get reference to dquot
 842  *
 843  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
 844  * destroying our dquot by:
 845  *   a) checking for quota flags under dq_list_lock and
 846  *   b) getting a reference to dquot before we release dq_list_lock
 847  */
 848 struct dquot *dqget(struct super_block *sb, struct kqid qid)
 849 {
 850         unsigned int hashent = hashfn(sb, qid);
 851         struct dquot *dquot, *empty = NULL;
 852 
 853         if (!qid_has_mapping(sb->s_user_ns, qid))
 854                 return ERR_PTR(-EINVAL);
 855 
 856         if (!sb_has_quota_active(sb, qid.type))
 857                 return ERR_PTR(-ESRCH);
 858 we_slept:
 859         spin_lock(&dq_list_lock);
 860         spin_lock(&dq_state_lock);
 861         if (!sb_has_quota_active(sb, qid.type)) {
 862                 spin_unlock(&dq_state_lock);
 863                 spin_unlock(&dq_list_lock);
 864                 dquot = ERR_PTR(-ESRCH);
 865                 goto out;
 866         }
 867         spin_unlock(&dq_state_lock);
 868 
 869         dquot = find_dquot(hashent, sb, qid);
 870         if (!dquot) {
 871                 if (!empty) {
 872                         spin_unlock(&dq_list_lock);
 873                         empty = get_empty_dquot(sb, qid.type);
 874                         if (!empty)
 875                                 schedule();     /* Try to wait for a moment... */
 876                         goto we_slept;
 877                 }
 878                 dquot = empty;
 879                 empty = NULL;
 880                 dquot->dq_id = qid;
 881                 /* all dquots go on the inuse_list */
 882                 put_inuse(dquot);
 883                 /* hash it first so it can be found */
 884                 insert_dquot_hash(dquot);
 885                 spin_unlock(&dq_list_lock);
 886                 dqstats_inc(DQST_LOOKUPS);
 887         } else {
 888                 if (!atomic_read(&dquot->dq_count))
 889                         remove_free_dquot(dquot);
 890                 atomic_inc(&dquot->dq_count);
 891                 spin_unlock(&dq_list_lock);
 892                 dqstats_inc(DQST_CACHE_HITS);
 893                 dqstats_inc(DQST_LOOKUPS);
 894         }
 895         /* Wait for dq_lock - after this we know that either dquot_release() is
 896          * already finished or it will be canceled due to dq_count > 1 test */
 897         wait_on_dquot(dquot);
 898         /* Read the dquot / allocate space in quota file */
 899         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 900                 int err;
 901 
 902                 err = sb->dq_op->acquire_dquot(dquot);
 903                 if (err < 0) {
 904                         dqput(dquot);
 905                         dquot = ERR_PTR(err);
 906                         goto out;
 907                 }
 908         }
 909         /*
 910          * Make sure following reads see filled structure - paired with
 911          * smp_mb__before_atomic() in dquot_acquire().
 912          */
 913         smp_rmb();
 914 #ifdef CONFIG_QUOTA_DEBUG
 915         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
 916 #endif
 917 out:
 918         if (empty)
 919                 do_destroy_dquot(empty);
 920 
 921         return dquot;
 922 }
 923 EXPORT_SYMBOL(dqget);
 924 
 925 static inline struct dquot **i_dquot(struct inode *inode)
 926 {
 927         return inode->i_sb->s_op->get_dquots(inode);
 928 }
 929 
 930 static int dqinit_needed(struct inode *inode, int type)
 931 {
 932         struct dquot * const *dquots;
 933         int cnt;
 934 
 935         if (IS_NOQUOTA(inode))
 936                 return 0;
 937 
 938         dquots = i_dquot(inode);
 939         if (type != -1)
 940                 return !dquots[type];
 941         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 942                 if (!dquots[cnt])
 943                         return 1;
 944         return 0;
 945 }
 946 
 947 /* This routine is guarded by s_umount semaphore */
 948 static int add_dquot_ref(struct super_block *sb, int type)
 949 {
 950         struct inode *inode, *old_inode = NULL;
 951 #ifdef CONFIG_QUOTA_DEBUG
 952         int reserved = 0;
 953 #endif
 954         int err = 0;
 955 
 956         spin_lock(&sb->s_inode_list_lock);
 957         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 958                 spin_lock(&inode->i_lock);
 959                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
 960                     !atomic_read(&inode->i_writecount) ||
 961                     !dqinit_needed(inode, type)) {
 962                         spin_unlock(&inode->i_lock);
 963                         continue;
 964                 }
 965                 __iget(inode);
 966                 spin_unlock(&inode->i_lock);
 967                 spin_unlock(&sb->s_inode_list_lock);
 968 
 969 #ifdef CONFIG_QUOTA_DEBUG
 970                 if (unlikely(inode_get_rsv_space(inode) > 0))
 971                         reserved = 1;
 972 #endif
 973                 iput(old_inode);
 974                 err = __dquot_initialize(inode, type);
 975                 if (err) {
 976                         iput(inode);
 977                         goto out;
 978                 }
 979 
 980                 /*
 981                  * We hold a reference to 'inode' so it couldn't have been
 982                  * removed from s_inodes list while we dropped the
 983                  * s_inode_list_lock. We cannot iput the inode now as we can be
 984                  * holding the last reference and we cannot iput it under
 985                  * s_inode_list_lock. So we keep the reference and iput it
 986                  * later.
 987                  */
 988                 old_inode = inode;
 989                 cond_resched();
 990                 spin_lock(&sb->s_inode_list_lock);
 991         }
 992         spin_unlock(&sb->s_inode_list_lock);
 993         iput(old_inode);
 994 out:
 995 #ifdef CONFIG_QUOTA_DEBUG
 996         if (reserved) {
 997                 quota_error(sb, "Writes happened before quota was turned on "
 998                         "thus quota information is probably inconsistent. "
 999                         "Please run quotacheck(8)");
1000         }
1001 #endif
1002         return err;
1003 }
1004 
1005 /*
1006  * Remove references to dquots from inode and add dquot to list for freeing
1007  * if we have the last reference to dquot
1008  */
1009 static void remove_inode_dquot_ref(struct inode *inode, int type,
1010                                    struct list_head *tofree_head)
1011 {
1012         struct dquot **dquots = i_dquot(inode);
1013         struct dquot *dquot = dquots[type];
1014 
1015         if (!dquot)
1016                 return;
1017 
1018         dquots[type] = NULL;
1019         if (list_empty(&dquot->dq_free)) {
1020                 /*
1021                  * The inode still has reference to dquot so it can't be in the
1022                  * free list
1023                  */
1024                 spin_lock(&dq_list_lock);
1025                 list_add(&dquot->dq_free, tofree_head);
1026                 spin_unlock(&dq_list_lock);
1027         } else {
1028                 /*
1029                  * Dquot is already in a list to put so we won't drop the last
1030                  * reference here.
1031                  */
1032                 dqput(dquot);
1033         }
1034 }
1035 
1036 /*
1037  * Free list of dquots
1038  * Dquots are removed from inodes and no new references can be got so we are
1039  * the only ones holding reference
1040  */
1041 static void put_dquot_list(struct list_head *tofree_head)
1042 {
1043         struct list_head *act_head;
1044         struct dquot *dquot;
1045 
1046         act_head = tofree_head->next;
1047         while (act_head != tofree_head) {
1048                 dquot = list_entry(act_head, struct dquot, dq_free);
1049                 act_head = act_head->next;
1050                 /* Remove dquot from the list so we won't have problems... */
1051                 list_del_init(&dquot->dq_free);
1052                 dqput(dquot);
1053         }
1054 }
1055 
1056 static void remove_dquot_ref(struct super_block *sb, int type,
1057                 struct list_head *tofree_head)
1058 {
1059         struct inode *inode;
1060 #ifdef CONFIG_QUOTA_DEBUG
1061         int reserved = 0;
1062 #endif
1063 
1064         spin_lock(&sb->s_inode_list_lock);
1065         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
1066                 /*
1067                  *  We have to scan also I_NEW inodes because they can already
1068                  *  have quota pointer initialized. Luckily, we need to touch
1069                  *  only quota pointers and these have separate locking
1070                  *  (dq_data_lock).
1071                  */
1072                 spin_lock(&dq_data_lock);
1073                 if (!IS_NOQUOTA(inode)) {
1074 #ifdef CONFIG_QUOTA_DEBUG
1075                         if (unlikely(inode_get_rsv_space(inode) > 0))
1076                                 reserved = 1;
1077 #endif
1078                         remove_inode_dquot_ref(inode, type, tofree_head);
1079                 }
1080                 spin_unlock(&dq_data_lock);
1081         }
1082         spin_unlock(&sb->s_inode_list_lock);
1083 #ifdef CONFIG_QUOTA_DEBUG
1084         if (reserved) {
1085                 printk(KERN_WARNING "VFS (%s): Writes happened after quota"
1086                         " was disabled thus quota information is probably "
1087                         "inconsistent. Please run quotacheck(8).\n", sb->s_id);
1088         }
1089 #endif
1090 }
1091 
1092 /* Gather all references from inodes and drop them */
1093 static void drop_dquot_ref(struct super_block *sb, int type)
1094 {
1095         LIST_HEAD(tofree_head);
1096 
1097         if (sb->dq_op) {
1098                 remove_dquot_ref(sb, type, &tofree_head);
1099                 synchronize_srcu(&dquot_srcu);
1100                 put_dquot_list(&tofree_head);
1101         }
1102 }
1103 
1104 static inline
1105 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
1106 {
1107         if (dquot->dq_dqb.dqb_rsvspace >= number)
1108                 dquot->dq_dqb.dqb_rsvspace -= number;
1109         else {
1110                 WARN_ON_ONCE(1);
1111                 dquot->dq_dqb.dqb_rsvspace = 0;
1112         }
1113         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1114             dquot->dq_dqb.dqb_bsoftlimit)
1115                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1116         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1117 }
1118 
1119 static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
1120 {
1121         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1122             dquot->dq_dqb.dqb_curinodes >= number)
1123                 dquot->dq_dqb.dqb_curinodes -= number;
1124         else
1125                 dquot->dq_dqb.dqb_curinodes = 0;
1126         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
1127                 dquot->dq_dqb.dqb_itime = (time64_t) 0;
1128         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1129 }
1130 
1131 static void dquot_decr_space(struct dquot *dquot, qsize_t number)
1132 {
1133         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
1134             dquot->dq_dqb.dqb_curspace >= number)
1135                 dquot->dq_dqb.dqb_curspace -= number;
1136         else
1137                 dquot->dq_dqb.dqb_curspace = 0;
1138         if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
1139             dquot->dq_dqb.dqb_bsoftlimit)
1140                 dquot->dq_dqb.dqb_btime = (time64_t) 0;
1141         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1142 }
1143 
1144 struct dquot_warn {
1145         struct super_block *w_sb;
1146         struct kqid w_dq_id;
1147         short w_type;
1148 };
1149 
1150 static int warning_issued(struct dquot *dquot, const int warntype)
1151 {
1152         int flag = (warntype == QUOTA_NL_BHARDWARN ||
1153                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
1154                 ((warntype == QUOTA_NL_IHARDWARN ||
1155                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
1156 
1157         if (!flag)
1158                 return 0;
1159         return test_and_set_bit(flag, &dquot->dq_flags);
1160 }
1161 
1162 #ifdef CONFIG_PRINT_QUOTA_WARNING
1163 static int flag_print_warnings = 1;
1164 
1165 static int need_print_warning(struct dquot_warn *warn)
1166 {
1167         if (!flag_print_warnings)
1168                 return 0;
1169 
1170         switch (warn->w_dq_id.type) {
1171                 case USRQUOTA:
1172                         return uid_eq(current_fsuid(), warn->w_dq_id.uid);
1173                 case GRPQUOTA:
1174                         return in_group_p(warn->w_dq_id.gid);
1175                 case PRJQUOTA:
1176                         return 1;
1177         }
1178         return 0;
1179 }
1180 
1181 /* Print warning to user which exceeded quota */
1182 static void print_warning(struct dquot_warn *warn)
1183 {
1184         char *msg = NULL;
1185         struct tty_struct *tty;
1186         int warntype = warn->w_type;
1187 
1188         if (warntype == QUOTA_NL_IHARDBELOW ||
1189             warntype == QUOTA_NL_ISOFTBELOW ||
1190             warntype == QUOTA_NL_BHARDBELOW ||
1191             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
1192                 return;
1193 
1194         tty = get_current_tty();
1195         if (!tty)
1196                 return;
1197         tty_write_message(tty, warn->w_sb->s_id);
1198         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
1199                 tty_write_message(tty, ": warning, ");
1200         else
1201                 tty_write_message(tty, ": write failed, ");
1202         tty_write_message(tty, quotatypes[warn->w_dq_id.type]);
1203         switch (warntype) {
1204                 case QUOTA_NL_IHARDWARN:
1205                         msg = " file limit reached.\r\n";
1206                         break;
1207                 case QUOTA_NL_ISOFTLONGWARN:
1208                         msg = " file quota exceeded too long.\r\n";
1209                         break;
1210                 case QUOTA_NL_ISOFTWARN:
1211                         msg = " file quota exceeded.\r\n";
1212                         break;
1213                 case QUOTA_NL_BHARDWARN:
1214                         msg = " block limit reached.\r\n";
1215                         break;
1216                 case QUOTA_NL_BSOFTLONGWARN:
1217                         msg = " block quota exceeded too long.\r\n";
1218                         break;
1219                 case QUOTA_NL_BSOFTWARN:
1220                         msg = " block quota exceeded.\r\n";
1221                         break;
1222         }
1223         tty_write_message(tty, msg);
1224         tty_kref_put(tty);
1225 }
1226 #endif
1227 
1228 static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
1229                             int warntype)
1230 {
1231         if (warning_issued(dquot, warntype))
1232                 return;
1233         warn->w_type = warntype;
1234         warn->w_sb = dquot->dq_sb;
1235         warn->w_dq_id = dquot->dq_id;
1236 }
1237 
1238 /*
1239  * Write warnings to the console and send warning messages over netlink.
1240  *
1241  * Note that this function can call into tty and networking code.
1242  */
1243 static void flush_warnings(struct dquot_warn *warn)
1244 {
1245         int i;
1246 
1247         for (i = 0; i < MAXQUOTAS; i++) {
1248                 if (warn[i].w_type == QUOTA_NL_NOWARN)
1249                         continue;
1250 #ifdef CONFIG_PRINT_QUOTA_WARNING
1251                 print_warning(&warn[i]);
1252 #endif
1253                 quota_send_warning(warn[i].w_dq_id,
1254                                    warn[i].w_sb->s_dev, warn[i].w_type);
1255         }
1256 }
1257 
1258 static int ignore_hardlimit(struct dquot *dquot)
1259 {
1260         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
1261 
1262         return capable(CAP_SYS_RESOURCE) &&
1263                (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
1264                 !(info->dqi_flags & DQF_ROOT_SQUASH));
1265 }
1266 
1267 static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
1268                             struct dquot_warn *warn)
1269 {
1270         qsize_t newinodes;
1271         int ret = 0;
1272 
1273         spin_lock(&dquot->dq_dqb_lock);
1274         newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
1275         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
1276             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1277                 goto add;
1278 
1279         if (dquot->dq_dqb.dqb_ihardlimit &&
1280             newinodes > dquot->dq_dqb.dqb_ihardlimit &&
1281             !ignore_hardlimit(dquot)) {
1282                 prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
1283                 ret = -EDQUOT;
1284                 goto out;
1285         }
1286 
1287         if (dquot->dq_dqb.dqb_isoftlimit &&
1288             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1289             dquot->dq_dqb.dqb_itime &&
1290             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
1291             !ignore_hardlimit(dquot)) {
1292                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
1293                 ret = -EDQUOT;
1294                 goto out;
1295         }
1296 
1297         if (dquot->dq_dqb.dqb_isoftlimit &&
1298             newinodes > dquot->dq_dqb.dqb_isoftlimit &&
1299             dquot->dq_dqb.dqb_itime == 0) {
1300                 prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
1301                 dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
1302                     sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
1303         }
1304 add:
1305         dquot->dq_dqb.dqb_curinodes = newinodes;
1306 
1307 out:
1308         spin_unlock(&dquot->dq_dqb_lock);
1309         return ret;
1310 }
1311 
1312 static int dquot_add_space(struct dquot *dquot, qsize_t space,
1313                            qsize_t rsv_space, unsigned int flags,
1314                            struct dquot_warn *warn)
1315 {
1316         qsize_t tspace;
1317         struct super_block *sb = dquot->dq_sb;
1318         int ret = 0;
1319 
1320         spin_lock(&dquot->dq_dqb_lock);
1321         if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
1322             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1323                 goto finish;
1324 
1325         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
1326                 + space + rsv_space;
1327 
1328         if (dquot->dq_dqb.dqb_bhardlimit &&
1329             tspace > dquot->dq_dqb.dqb_bhardlimit &&
1330             !ignore_hardlimit(dquot)) {
1331                 if (flags & DQUOT_SPACE_WARN)
1332                         prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
1333                 ret = -EDQUOT;
1334                 goto finish;
1335         }
1336 
1337         if (dquot->dq_dqb.dqb_bsoftlimit &&
1338             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1339             dquot->dq_dqb.dqb_btime &&
1340             ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
1341             !ignore_hardlimit(dquot)) {
1342                 if (flags & DQUOT_SPACE_WARN)
1343                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
1344                 ret = -EDQUOT;
1345                 goto finish;
1346         }
1347 
1348         if (dquot->dq_dqb.dqb_bsoftlimit &&
1349             tspace > dquot->dq_dqb.dqb_bsoftlimit &&
1350             dquot->dq_dqb.dqb_btime == 0) {
1351                 if (flags & DQUOT_SPACE_WARN) {
1352                         prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
1353                         dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
1354                             sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
1355                 } else {
1356                         /*
1357                          * We don't allow preallocation to exceed softlimit so exceeding will
1358                          * be always printed
1359                          */
1360                         ret = -EDQUOT;
1361                         goto finish;
1362                 }
1363         }
1364 finish:
1365         /*
1366          * We have to be careful and go through warning generation & grace time
1367          * setting even if DQUOT_SPACE_NOFAIL is set. That's why we check it
1368          * only here...
1369          */
1370         if (flags & DQUOT_SPACE_NOFAIL)
1371                 ret = 0;
1372         if (!ret) {
1373                 dquot->dq_dqb.dqb_rsvspace += rsv_space;
1374                 dquot->dq_dqb.dqb_curspace += space;
1375         }
1376         spin_unlock(&dquot->dq_dqb_lock);
1377         return ret;
1378 }
1379 
1380 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1381 {
1382         qsize_t newinodes;
1383 
1384         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1385             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1386             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
1387                 return QUOTA_NL_NOWARN;
1388 
1389         newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
1390         if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
1391                 return QUOTA_NL_ISOFTBELOW;
1392         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1393             newinodes < dquot->dq_dqb.dqb_ihardlimit)
1394                 return QUOTA_NL_IHARDBELOW;
1395         return QUOTA_NL_NOWARN;
1396 }
1397 
1398 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1399 {
1400         qsize_t tspace;
1401 
1402         tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace;
1403 
1404         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1405             tspace <= dquot->dq_dqb.dqb_bsoftlimit)
1406                 return QUOTA_NL_NOWARN;
1407 
1408         if (tspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1409                 return QUOTA_NL_BSOFTBELOW;
1410         if (tspace >= dquot->dq_dqb.dqb_bhardlimit &&
1411             tspace - space < dquot->dq_dqb.dqb_bhardlimit)
1412                 return QUOTA_NL_BHARDBELOW;
1413         return QUOTA_NL_NOWARN;
1414 }
1415 
1416 static int dquot_active(const struct inode *inode)
1417 {
1418         struct super_block *sb = inode->i_sb;
1419 
1420         if (IS_NOQUOTA(inode))
1421                 return 0;
1422         return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
1423 }
1424 
1425 /*
1426  * Initialize quota pointers in inode
1427  *
1428  * It is better to call this function outside of any transaction as it
1429  * might need a lot of space in journal for dquot structure allocation.
1430  */
1431 static int __dquot_initialize(struct inode *inode, int type)
1432 {
1433         int cnt, init_needed = 0;
1434         struct dquot **dquots, *got[MAXQUOTAS] = {};
1435         struct super_block *sb = inode->i_sb;
1436         qsize_t rsv;
1437         int ret = 0;
1438 
1439         if (!dquot_active(inode))
1440                 return 0;
1441 
1442         dquots = i_dquot(inode);
1443 
1444         /* First get references to structures we might need. */
1445         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1446                 struct kqid qid;
1447                 kprojid_t projid;
1448                 int rc;
1449                 struct dquot *dquot;
1450 
1451                 if (type != -1 && cnt != type)
1452                         continue;
1453                 /*
1454                  * The i_dquot should have been initialized in most cases,
1455                  * we check it without locking here to avoid unnecessary
1456                  * dqget()/dqput() calls.
1457                  */
1458                 if (dquots[cnt])
1459                         continue;
1460 
1461                 if (!sb_has_quota_active(sb, cnt))
1462                         continue;
1463 
1464                 init_needed = 1;
1465 
1466                 switch (cnt) {
1467                 case USRQUOTA:
1468                         qid = make_kqid_uid(inode->i_uid);
1469                         break;
1470                 case GRPQUOTA:
1471                         qid = make_kqid_gid(inode->i_gid);
1472                         break;
1473                 case PRJQUOTA:
1474                         rc = inode->i_sb->dq_op->get_projid(inode, &projid);
1475                         if (rc)
1476                                 continue;
1477                         qid = make_kqid_projid(projid);
1478                         break;
1479                 }
1480                 dquot = dqget(sb, qid);
1481                 if (IS_ERR(dquot)) {
1482                         /* We raced with somebody turning quotas off... */
1483                         if (PTR_ERR(dquot) != -ESRCH) {
1484                                 ret = PTR_ERR(dquot);
1485                                 goto out_put;
1486                         }
1487                         dquot = NULL;
1488                 }
1489                 got[cnt] = dquot;
1490         }
1491 
1492         /* All required i_dquot has been initialized */
1493         if (!init_needed)
1494                 return 0;
1495 
1496         spin_lock(&dq_data_lock);
1497         if (IS_NOQUOTA(inode))
1498                 goto out_lock;
1499         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1500                 if (type != -1 && cnt != type)
1501                         continue;
1502                 /* Avoid races with quotaoff() */
1503                 if (!sb_has_quota_active(sb, cnt))
1504                         continue;
1505                 /* We could race with quotaon or dqget() could have failed */
1506                 if (!got[cnt])
1507                         continue;
1508                 if (!dquots[cnt]) {
1509                         dquots[cnt] = got[cnt];
1510                         got[cnt] = NULL;
1511                         /*
1512                          * Make quota reservation system happy if someone
1513                          * did a write before quota was turned on
1514                          */
1515                         rsv = inode_get_rsv_space(inode);
1516                         if (unlikely(rsv)) {
1517                                 spin_lock(&inode->i_lock);
1518                                 /* Get reservation again under proper lock */
1519                                 rsv = __inode_get_rsv_space(inode);
1520                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1521                                 dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
1522                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1523                                 spin_unlock(&inode->i_lock);
1524                         }
1525                 }
1526         }
1527 out_lock:
1528         spin_unlock(&dq_data_lock);
1529 out_put:
1530         /* Drop unused references */
1531         dqput_all(got);
1532 
1533         return ret;
1534 }
1535 
1536 int dquot_initialize(struct inode *inode)
1537 {
1538         return __dquot_initialize(inode, -1);
1539 }
1540 EXPORT_SYMBOL(dquot_initialize);
1541 
1542 bool dquot_initialize_needed(struct inode *inode)
1543 {
1544         struct dquot **dquots;
1545         int i;
1546 
1547         if (!dquot_active(inode))
1548                 return false;
1549 
1550         dquots = i_dquot(inode);
1551         for (i = 0; i < MAXQUOTAS; i++)
1552                 if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
1553                         return true;
1554         return false;
1555 }
1556 EXPORT_SYMBOL(dquot_initialize_needed);
1557 
1558 /*
1559  * Release all quotas referenced by inode.
1560  *
1561  * This function only be called on inode free or converting
1562  * a file to quota file, no other users for the i_dquot in
1563  * both cases, so we needn't call synchronize_srcu() after
1564  * clearing i_dquot.
1565  */
1566 static void __dquot_drop(struct inode *inode)
1567 {
1568         int cnt;
1569         struct dquot **dquots = i_dquot(inode);
1570         struct dquot *put[MAXQUOTAS];
1571 
1572         spin_lock(&dq_data_lock);
1573         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1574                 put[cnt] = dquots[cnt];
1575                 dquots[cnt] = NULL;
1576         }
1577         spin_unlock(&dq_data_lock);
1578         dqput_all(put);
1579 }
1580 
1581 void dquot_drop(struct inode *inode)
1582 {
1583         struct dquot * const *dquots;
1584         int cnt;
1585 
1586         if (IS_NOQUOTA(inode))
1587                 return;
1588 
1589         /*
1590          * Test before calling to rule out calls from proc and such
1591          * where we are not allowed to block. Note that this is
1592          * actually reliable test even without the lock - the caller
1593          * must assure that nobody can come after the DQUOT_DROP and
1594          * add quota pointers back anyway.
1595          */
1596         dquots = i_dquot(inode);
1597         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1598                 if (dquots[cnt])
1599                         break;
1600         }
1601 
1602         if (cnt < MAXQUOTAS)
1603                 __dquot_drop(inode);
1604 }
1605 EXPORT_SYMBOL(dquot_drop);
1606 
1607 /*
1608  * inode_reserved_space is managed internally by quota, and protected by
1609  * i_lock similar to i_blocks+i_bytes.
1610  */
1611 static qsize_t *inode_reserved_space(struct inode * inode)
1612 {
1613         /* Filesystem must explicitly define it's own method in order to use
1614          * quota reservation interface */
1615         BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
1616         return inode->i_sb->dq_op->get_reserved_space(inode);
1617 }
1618 
1619 static qsize_t __inode_get_rsv_space(struct inode *inode)
1620 {
1621         if (!inode->i_sb->dq_op->get_reserved_space)
1622                 return 0;
1623         return *inode_reserved_space(inode);
1624 }
1625 
1626 static qsize_t inode_get_rsv_space(struct inode *inode)
1627 {
1628         qsize_t ret;
1629 
1630         if (!inode->i_sb->dq_op->get_reserved_space)
1631                 return 0;
1632         spin_lock(&inode->i_lock);
1633         ret = __inode_get_rsv_space(inode);
1634         spin_unlock(&inode->i_lock);
1635         return ret;
1636 }
1637 
1638 /*
1639  * This functions updates i_blocks+i_bytes fields and quota information
1640  * (together with appropriate checks).
1641  *
1642  * NOTE: We absolutely rely on the fact that caller dirties the inode
1643  * (usually helpers in quotaops.h care about this) and holds a handle for
1644  * the current transaction so that dquot write and inode write go into the
1645  * same transaction.
1646  */
1647 
1648 /*
1649  * This operation can block, but only after everything is updated
1650  */
1651 int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
1652 {
1653         int cnt, ret = 0, index;
1654         struct dquot_warn warn[MAXQUOTAS];
1655         int reserve = flags & DQUOT_SPACE_RESERVE;
1656         struct dquot **dquots;
1657 
1658         if (!dquot_active(inode)) {
1659                 if (reserve) {
1660                         spin_lock(&inode->i_lock);
1661                         *inode_reserved_space(inode) += number;
1662                         spin_unlock(&inode->i_lock);
1663                 } else {
1664                         inode_add_bytes(inode, number);
1665                 }
1666                 goto out;
1667         }
1668 
1669         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1670                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1671 
1672         dquots = i_dquot(inode);
1673         index = srcu_read_lock(&dquot_srcu);
1674         spin_lock(&inode->i_lock);
1675         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1676                 if (!dquots[cnt])
1677                         continue;
1678                 if (reserve) {
1679                         ret = dquot_add_space(dquots[cnt], 0, number, flags,
1680                                               &warn[cnt]);
1681                 } else {
1682                         ret = dquot_add_space(dquots[cnt], number, 0, flags,
1683                                               &warn[cnt]);
1684                 }
1685                 if (ret) {
1686                         /* Back out changes we already did */
1687                         for (cnt--; cnt >= 0; cnt--) {
1688                                 if (!dquots[cnt])
1689                                         continue;
1690                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1691                                 if (reserve)
1692                                         dquot_free_reserved_space(dquots[cnt],
1693                                                                   number);
1694                                 else
1695                                         dquot_decr_space(dquots[cnt], number);
1696                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1697                         }
1698                         spin_unlock(&inode->i_lock);
1699                         goto out_flush_warn;
1700                 }
1701         }
1702         if (reserve)
1703                 *inode_reserved_space(inode) += number;
1704         else
1705                 __inode_add_bytes(inode, number);
1706         spin_unlock(&inode->i_lock);
1707 
1708         if (reserve)
1709                 goto out_flush_warn;
1710         mark_all_dquot_dirty(dquots);
1711 out_flush_warn:
1712         srcu_read_unlock(&dquot_srcu, index);
1713         flush_warnings(warn);
1714 out:
1715         return ret;
1716 }
1717 EXPORT_SYMBOL(__dquot_alloc_space);
1718 
1719 /*
1720  * This operation can block, but only after everything is updated
1721  */
1722 int dquot_alloc_inode(struct inode *inode)
1723 {
1724         int cnt, ret = 0, index;
1725         struct dquot_warn warn[MAXQUOTAS];
1726         struct dquot * const *dquots;
1727 
1728         if (!dquot_active(inode))
1729                 return 0;
1730         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1731                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1732 
1733         dquots = i_dquot(inode);
1734         index = srcu_read_lock(&dquot_srcu);
1735         spin_lock(&inode->i_lock);
1736         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1737                 if (!dquots[cnt])
1738                         continue;
1739                 ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
1740                 if (ret) {
1741                         for (cnt--; cnt >= 0; cnt--) {
1742                                 if (!dquots[cnt])
1743                                         continue;
1744                                 /* Back out changes we already did */
1745                                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1746                                 dquot_decr_inodes(dquots[cnt], 1);
1747                                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1748                         }
1749                         goto warn_put_all;
1750                 }
1751         }
1752 
1753 warn_put_all:
1754         spin_unlock(&inode->i_lock);
1755         if (ret == 0)
1756                 mark_all_dquot_dirty(dquots);
1757         srcu_read_unlock(&dquot_srcu, index);
1758         flush_warnings(warn);
1759         return ret;
1760 }
1761 EXPORT_SYMBOL(dquot_alloc_inode);
1762 
1763 /*
1764  * Convert in-memory reserved quotas to real consumed quotas
1765  */
1766 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
1767 {
1768         struct dquot **dquots;
1769         int cnt, index;
1770 
1771         if (!dquot_active(inode)) {
1772                 spin_lock(&inode->i_lock);
1773                 *inode_reserved_space(inode) -= number;
1774                 __inode_add_bytes(inode, number);
1775                 spin_unlock(&inode->i_lock);
1776                 return 0;
1777         }
1778 
1779         dquots = i_dquot(inode);
1780         index = srcu_read_lock(&dquot_srcu);
1781         spin_lock(&inode->i_lock);
1782         /* Claim reserved quotas to allocated quotas */
1783         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1784                 if (dquots[cnt]) {
1785                         struct dquot *dquot = dquots[cnt];
1786 
1787                         spin_lock(&dquot->dq_dqb_lock);
1788                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
1789                                 number = dquot->dq_dqb.dqb_rsvspace;
1790                         dquot->dq_dqb.dqb_curspace += number;
1791                         dquot->dq_dqb.dqb_rsvspace -= number;
1792                         spin_unlock(&dquot->dq_dqb_lock);
1793                 }
1794         }
1795         /* Update inode bytes */
1796         *inode_reserved_space(inode) -= number;
1797         __inode_add_bytes(inode, number);
1798         spin_unlock(&inode->i_lock);
1799         mark_all_dquot_dirty(dquots);
1800         srcu_read_unlock(&dquot_srcu, index);
1801         return 0;
1802 }
1803 EXPORT_SYMBOL(dquot_claim_space_nodirty);
1804 
1805 /*
1806  * Convert allocated space back to in-memory reserved quotas
1807  */
1808 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
1809 {
1810         struct dquot **dquots;
1811         int cnt, index;
1812 
1813         if (!dquot_active(inode)) {
1814                 spin_lock(&inode->i_lock);
1815                 *inode_reserved_space(inode) += number;
1816                 __inode_sub_bytes(inode, number);
1817                 spin_unlock(&inode->i_lock);
1818                 return;
1819         }
1820 
1821         dquots = i_dquot(inode);
1822         index = srcu_read_lock(&dquot_srcu);
1823         spin_lock(&inode->i_lock);
1824         /* Claim reserved quotas to allocated quotas */
1825         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1826                 if (dquots[cnt]) {
1827                         struct dquot *dquot = dquots[cnt];
1828 
1829                         spin_lock(&dquot->dq_dqb_lock);
1830                         if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
1831                                 number = dquot->dq_dqb.dqb_curspace;
1832                         dquot->dq_dqb.dqb_rsvspace += number;
1833                         dquot->dq_dqb.dqb_curspace -= number;
1834                         spin_unlock(&dquot->dq_dqb_lock);
1835                 }
1836         }
1837         /* Update inode bytes */
1838         *inode_reserved_space(inode) += number;
1839         __inode_sub_bytes(inode, number);
1840         spin_unlock(&inode->i_lock);
1841         mark_all_dquot_dirty(dquots);
1842         srcu_read_unlock(&dquot_srcu, index);
1843         return;
1844 }
1845 EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
1846 
1847 /*
1848  * This operation can block, but only after everything is updated
1849  */
1850 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
1851 {
1852         unsigned int cnt;
1853         struct dquot_warn warn[MAXQUOTAS];
1854         struct dquot **dquots;
1855         int reserve = flags & DQUOT_SPACE_RESERVE, index;
1856 
1857         if (!dquot_active(inode)) {
1858                 if (reserve) {
1859                         spin_lock(&inode->i_lock);
1860                         *inode_reserved_space(inode) -= number;
1861                         spin_unlock(&inode->i_lock);
1862                 } else {
1863                         inode_sub_bytes(inode, number);
1864                 }
1865                 return;
1866         }
1867 
1868         dquots = i_dquot(inode);
1869         index = srcu_read_lock(&dquot_srcu);
1870         spin_lock(&inode->i_lock);
1871         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1872                 int wtype;
1873 
1874                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1875                 if (!dquots[cnt])
1876                         continue;
1877                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1878                 wtype = info_bdq_free(dquots[cnt], number);
1879                 if (wtype != QUOTA_NL_NOWARN)
1880                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1881                 if (reserve)
1882                         dquot_free_reserved_space(dquots[cnt], number);
1883                 else
1884                         dquot_decr_space(dquots[cnt], number);
1885                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1886         }
1887         if (reserve)
1888                 *inode_reserved_space(inode) -= number;
1889         else
1890                 __inode_sub_bytes(inode, number);
1891         spin_unlock(&inode->i_lock);
1892 
1893         if (reserve)
1894                 goto out_unlock;
1895         mark_all_dquot_dirty(dquots);
1896 out_unlock:
1897         srcu_read_unlock(&dquot_srcu, index);
1898         flush_warnings(warn);
1899 }
1900 EXPORT_SYMBOL(__dquot_free_space);
1901 
1902 /*
1903  * This operation can block, but only after everything is updated
1904  */
1905 void dquot_free_inode(struct inode *inode)
1906 {
1907         unsigned int cnt;
1908         struct dquot_warn warn[MAXQUOTAS];
1909         struct dquot * const *dquots;
1910         int index;
1911 
1912         if (!dquot_active(inode))
1913                 return;
1914 
1915         dquots = i_dquot(inode);
1916         index = srcu_read_lock(&dquot_srcu);
1917         spin_lock(&inode->i_lock);
1918         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1919                 int wtype;
1920 
1921                 warn[cnt].w_type = QUOTA_NL_NOWARN;
1922                 if (!dquots[cnt])
1923                         continue;
1924                 spin_lock(&dquots[cnt]->dq_dqb_lock);
1925                 wtype = info_idq_free(dquots[cnt], 1);
1926                 if (wtype != QUOTA_NL_NOWARN)
1927                         prepare_warning(&warn[cnt], dquots[cnt], wtype);
1928                 dquot_decr_inodes(dquots[cnt], 1);
1929                 spin_unlock(&dquots[cnt]->dq_dqb_lock);
1930         }
1931         spin_unlock(&inode->i_lock);
1932         mark_all_dquot_dirty(dquots);
1933         srcu_read_unlock(&dquot_srcu, index);
1934         flush_warnings(warn);
1935 }
1936 EXPORT_SYMBOL(dquot_free_inode);
1937 
1938 /*
1939  * Transfer the number of inode and blocks from one diskquota to an other.
1940  * On success, dquot references in transfer_to are consumed and references
1941  * to original dquots that need to be released are placed there. On failure,
1942  * references are kept untouched.
1943  *
1944  * This operation can block, but only after everything is updated
1945  * A transaction must be started when entering this function.
1946  *
1947  * We are holding reference on transfer_from & transfer_to, no need to
1948  * protect them by srcu_read_lock().
1949  */
1950 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
1951 {
1952         qsize_t cur_space;
1953         qsize_t rsv_space = 0;
1954         qsize_t inode_usage = 1;
1955         struct dquot *transfer_from[MAXQUOTAS] = {};
1956         int cnt, ret = 0;
1957         char is_valid[MAXQUOTAS] = {};
1958         struct dquot_warn warn_to[MAXQUOTAS];
1959         struct dquot_warn warn_from_inodes[MAXQUOTAS];
1960         struct dquot_warn warn_from_space[MAXQUOTAS];
1961 
1962         if (IS_NOQUOTA(inode))
1963                 return 0;
1964 
1965         if (inode->i_sb->dq_op->get_inode_usage) {
1966                 ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
1967                 if (ret)
1968                         return ret;
1969         }
1970 
1971         /* Initialize the arrays */
1972         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1973                 warn_to[cnt].w_type = QUOTA_NL_NOWARN;
1974                 warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
1975                 warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
1976         }
1977 
1978         spin_lock(&dq_data_lock);
1979         spin_lock(&inode->i_lock);
1980         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1981                 spin_unlock(&inode->i_lock);
1982                 spin_unlock(&dq_data_lock);
1983                 return 0;
1984         }
1985         cur_space = __inode_get_bytes(inode);
1986         rsv_space = __inode_get_rsv_space(inode);
1987         /*
1988          * Build the transfer_from list, check limits, and update usage in
1989          * the target structures.
1990          */
1991         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1992                 /*
1993                  * Skip changes for same uid or gid or for turned off quota-type.
1994                  */
1995                 if (!transfer_to[cnt])
1996                         continue;
1997                 /* Avoid races with quotaoff() */
1998                 if (!sb_has_quota_active(inode->i_sb, cnt))
1999                         continue;
2000                 is_valid[cnt] = 1;
2001                 transfer_from[cnt] = i_dquot(inode)[cnt];
2002                 ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
2003                                        &warn_to[cnt]);
2004                 if (ret)
2005                         goto over_quota;
2006                 ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space,
2007                                       DQUOT_SPACE_WARN, &warn_to[cnt]);
2008                 if (ret) {
2009                         spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2010                         dquot_decr_inodes(transfer_to[cnt], inode_usage);
2011                         spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2012                         goto over_quota;
2013                 }
2014         }
2015 
2016         /* Decrease usage for source structures and update quota pointers */
2017         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2018                 if (!is_valid[cnt])
2019                         continue;
2020                 /* Due to IO error we might not have transfer_from[] structure */
2021                 if (transfer_from[cnt]) {
2022                         int wtype;
2023 
2024                         spin_lock(&transfer_from[cnt]->dq_dqb_lock);
2025                         wtype = info_idq_free(transfer_from[cnt], inode_usage);
2026                         if (wtype != QUOTA_NL_NOWARN)
2027                                 prepare_warning(&warn_from_inodes[cnt],
2028                                                 transfer_from[cnt], wtype);
2029                         wtype = info_bdq_free(transfer_from[cnt],
2030                                               cur_space + rsv_space);
2031                         if (wtype != QUOTA_NL_NOWARN)
2032                                 prepare_warning(&warn_from_space[cnt],
2033                                                 transfer_from[cnt], wtype);
2034                         dquot_decr_inodes(transfer_from[cnt], inode_usage);
2035                         dquot_decr_space(transfer_from[cnt], cur_space);
2036                         dquot_free_reserved_space(transfer_from[cnt],
2037                                                   rsv_space);
2038                         spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
2039                 }
2040                 i_dquot(inode)[cnt] = transfer_to[cnt];
2041         }
2042         spin_unlock(&inode->i_lock);
2043         spin_unlock(&dq_data_lock);
2044 
2045         mark_all_dquot_dirty(transfer_from);
2046         mark_all_dquot_dirty(transfer_to);
2047         flush_warnings(warn_to);
2048         flush_warnings(warn_from_inodes);
2049         flush_warnings(warn_from_space);
2050         /* Pass back references to put */
2051         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2052                 if (is_valid[cnt])
2053                         transfer_to[cnt] = transfer_from[cnt];
2054         return 0;
2055 over_quota:
2056         /* Back out changes we already did */
2057         for (cnt--; cnt >= 0; cnt--) {
2058                 if (!is_valid[cnt])
2059                         continue;
2060                 spin_lock(&transfer_to[cnt]->dq_dqb_lock);
2061                 dquot_decr_inodes(transfer_to[cnt], inode_usage);
2062                 dquot_decr_space(transfer_to[cnt], cur_space);
2063                 dquot_free_reserved_space(transfer_to[cnt], rsv_space);
2064                 spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
2065         }
2066         spin_unlock(&inode->i_lock);
2067         spin_unlock(&dq_data_lock);
2068         flush_warnings(warn_to);
2069         return ret;
2070 }
2071 EXPORT_SYMBOL(__dquot_transfer);
2072 
2073 /* Wrapper for transferring ownership of an inode for uid/gid only
2074  * Called from FSXXX_setattr()
2075  */
2076 int dquot_transfer(struct inode *inode, struct iattr *iattr)
2077 {
2078         struct dquot *transfer_to[MAXQUOTAS] = {};
2079         struct dquot *dquot;
2080         struct super_block *sb = inode->i_sb;
2081         int ret;
2082 
2083         if (!dquot_active(inode))
2084                 return 0;
2085 
2086         if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
2087                 dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
2088                 if (IS_ERR(dquot)) {
2089                         if (PTR_ERR(dquot) != -ESRCH) {
2090                                 ret = PTR_ERR(dquot);
2091                                 goto out_put;
2092                         }
2093                         dquot = NULL;
2094                 }
2095                 transfer_to[USRQUOTA] = dquot;
2096         }
2097         if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
2098                 dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
2099                 if (IS_ERR(dquot)) {
2100                         if (PTR_ERR(dquot) != -ESRCH) {
2101                                 ret = PTR_ERR(dquot);
2102                                 goto out_put;
2103                         }
2104                         dquot = NULL;
2105                 }
2106                 transfer_to[GRPQUOTA] = dquot;
2107         }
2108         ret = __dquot_transfer(inode, transfer_to);
2109 out_put:
2110         dqput_all(transfer_to);
2111         return ret;
2112 }
2113 EXPORT_SYMBOL(dquot_transfer);
2114 
2115 /*
2116  * Write info of quota file to disk
2117  */
2118 int dquot_commit_info(struct super_block *sb, int type)
2119 {
2120         struct quota_info *dqopt = sb_dqopt(sb);
2121 
2122         return dqopt->ops[type]->write_file_info(sb, type);
2123 }
2124 EXPORT_SYMBOL(dquot_commit_info);
2125 
2126 int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
2127 {
2128         struct quota_info *dqopt = sb_dqopt(sb);
2129 
2130         if (!sb_has_quota_active(sb, qid->type))
2131                 return -ESRCH;
2132         if (!dqopt->ops[qid->type]->get_next_id)
2133                 return -ENOSYS;
2134         return dqopt->ops[qid->type]->get_next_id(sb, qid);
2135 }
2136 EXPORT_SYMBOL(dquot_get_next_id);
2137 
2138 /*
2139  * Definitions of diskquota operations.
2140  */
2141 const struct dquot_operations dquot_operations = {
2142         .write_dquot    = dquot_commit,
2143         .acquire_dquot  = dquot_acquire,
2144         .release_dquot  = dquot_release,
2145         .mark_dirty     = dquot_mark_dquot_dirty,
2146         .write_info     = dquot_commit_info,
2147         .alloc_dquot    = dquot_alloc,
2148         .destroy_dquot  = dquot_destroy,
2149         .get_next_id    = dquot_get_next_id,
2150 };
2151 EXPORT_SYMBOL(dquot_operations);
2152 
2153 /*
2154  * Generic helper for ->open on filesystems supporting disk quotas.
2155  */
2156 int dquot_file_open(struct inode *inode, struct file *file)
2157 {
2158         int error;
2159 
2160         error = generic_file_open(inode, file);
2161         if (!error && (file->f_mode & FMODE_WRITE))
2162                 error = dquot_initialize(inode);
2163         return error;
2164 }
2165 EXPORT_SYMBOL(dquot_file_open);
2166 
2167 /*
2168  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
2169  */
2170 int dquot_disable(struct super_block *sb, int type, unsigned int flags)
2171 {
2172         int cnt, ret = 0;
2173         struct quota_info *dqopt = sb_dqopt(sb);
2174         struct inode *toputinode[MAXQUOTAS];
2175 
2176         /* s_umount should be held in exclusive mode */
2177         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2178                 up_read(&sb->s_umount);
2179 
2180         /* Cannot turn off usage accounting without turning off limits, or
2181          * suspend quotas and simultaneously turn quotas off. */
2182         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
2183             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
2184             DQUOT_USAGE_ENABLED)))
2185                 return -EINVAL;
2186 
2187         /*
2188          * Skip everything if there's nothing to do. We have to do this because
2189          * sometimes we are called when fill_super() failed and calling
2190          * sync_fs() in such cases does no good.
2191          */
2192         if (!sb_any_quota_loaded(sb))
2193                 return 0;
2194 
2195         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2196                 toputinode[cnt] = NULL;
2197                 if (type != -1 && cnt != type)
2198                         continue;
2199                 if (!sb_has_quota_loaded(sb, cnt))
2200                         continue;
2201 
2202                 if (flags & DQUOT_SUSPENDED) {
2203                         spin_lock(&dq_state_lock);
2204                         dqopt->flags |=
2205                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
2206                         spin_unlock(&dq_state_lock);
2207                 } else {
2208                         spin_lock(&dq_state_lock);
2209                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
2210                         /* Turning off suspended quotas? */
2211                         if (!sb_has_quota_loaded(sb, cnt) &&
2212                             sb_has_quota_suspended(sb, cnt)) {
2213                                 dqopt->flags &= ~dquot_state_flag(
2214                                                         DQUOT_SUSPENDED, cnt);
2215                                 spin_unlock(&dq_state_lock);
2216                                 iput(dqopt->files[cnt]);
2217                                 dqopt->files[cnt] = NULL;
2218                                 continue;
2219                         }
2220                         spin_unlock(&dq_state_lock);
2221                 }
2222 
2223                 /* We still have to keep quota loaded? */
2224                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
2225                         continue;
2226 
2227                 /* Note: these are blocking operations */
2228                 drop_dquot_ref(sb, cnt);
2229                 invalidate_dquots(sb, cnt);
2230                 /*
2231                  * Now all dquots should be invalidated, all writes done so we
2232                  * should be only users of the info. No locks needed.
2233                  */
2234                 if (info_dirty(&dqopt->info[cnt]))
2235                         sb->dq_op->write_info(sb, cnt);
2236                 if (dqopt->ops[cnt]->free_file_info)
2237                         dqopt->ops[cnt]->free_file_info(sb, cnt);
2238                 put_quota_format(dqopt->info[cnt].dqi_format);
2239 
2240                 toputinode[cnt] = dqopt->files[cnt];
2241                 if (!sb_has_quota_loaded(sb, cnt))
2242                         dqopt->files[cnt] = NULL;
2243                 dqopt->info[cnt].dqi_flags = 0;
2244                 dqopt->info[cnt].dqi_igrace = 0;
2245                 dqopt->info[cnt].dqi_bgrace = 0;
2246                 dqopt->ops[cnt] = NULL;
2247         }
2248 
2249         /* Skip syncing and setting flags if quota files are hidden */
2250         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
2251                 goto put_inodes;
2252 
2253         /* Sync the superblock so that buffers with quota data are written to
2254          * disk (and so userspace sees correct data afterwards). */
2255         if (sb->s_op->sync_fs)
2256                 sb->s_op->sync_fs(sb, 1);
2257         sync_blockdev(sb->s_bdev);
2258         /* Now the quota files are just ordinary files and we can set the
2259          * inode flags back. Moreover we discard the pagecache so that
2260          * userspace sees the writes we did bypassing the pagecache. We
2261          * must also discard the blockdev buffers so that we see the
2262          * changes done by userspace on the next quotaon() */
2263         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2264                 /* This can happen when suspending quotas on remount-ro... */
2265                 if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {
2266                         inode_lock(toputinode[cnt]);
2267                         toputinode[cnt]->i_flags &= ~S_NOQUOTA;
2268                         truncate_inode_pages(&toputinode[cnt]->i_data, 0);
2269                         inode_unlock(toputinode[cnt]);
2270                         mark_inode_dirty_sync(toputinode[cnt]);
2271                 }
2272         if (sb->s_bdev)
2273                 invalidate_bdev(sb->s_bdev);
2274 put_inodes:
2275         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
2276                 if (toputinode[cnt]) {
2277                         /* On remount RO, we keep the inode pointer so that we
2278                          * can reenable quota on the subsequent remount RW. We
2279                          * have to check 'flags' variable and not use sb_has_
2280                          * function because another quotaon / quotaoff could
2281                          * change global state before we got here. We refuse
2282                          * to suspend quotas when there is pending delete on
2283                          * the quota file... */
2284                         if (!(flags & DQUOT_SUSPENDED))
2285                                 iput(toputinode[cnt]);
2286                         else if (!toputinode[cnt]->i_nlink)
2287                                 ret = -EBUSY;
2288                 }
2289         return ret;
2290 }
2291 EXPORT_SYMBOL(dquot_disable);
2292 
2293 int dquot_quota_off(struct super_block *sb, int type)
2294 {
2295         return dquot_disable(sb, type,
2296                              DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2297 }
2298 EXPORT_SYMBOL(dquot_quota_off);
2299 
2300 /*
2301  *      Turn quotas on on a device
2302  */
2303 
2304 /*
2305  * Helper function to turn quotas on when we already have the inode of
2306  * quota file and no quota information is loaded.
2307  */
2308 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
2309         unsigned int flags)
2310 {
2311         struct quota_format_type *fmt = find_quota_format(format_id);
2312         struct super_block *sb = inode->i_sb;
2313         struct quota_info *dqopt = sb_dqopt(sb);
2314         int error;
2315 
2316         if (!fmt)
2317                 return -ESRCH;
2318         if (!S_ISREG(inode->i_mode)) {
2319                 error = -EACCES;
2320                 goto out_fmt;
2321         }
2322         if (IS_RDONLY(inode)) {
2323                 error = -EROFS;
2324                 goto out_fmt;
2325         }
2326         if (!sb->s_op->quota_write || !sb->s_op->quota_read ||
2327             (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
2328                 error = -EINVAL;
2329                 goto out_fmt;
2330         }
2331         /* Filesystems outside of init_user_ns not yet supported */
2332         if (sb->s_user_ns != &init_user_ns) {
2333                 error = -EINVAL;
2334                 goto out_fmt;
2335         }
2336         /* Usage always has to be set... */
2337         if (!(flags & DQUOT_USAGE_ENABLED)) {
2338                 error = -EINVAL;
2339                 goto out_fmt;
2340         }
2341         if (sb_has_quota_loaded(sb, type)) {
2342                 error = -EBUSY;
2343                 goto out_fmt;
2344         }
2345 
2346         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2347                 /* As we bypass the pagecache we must now flush all the
2348                  * dirty data and invalidate caches so that kernel sees
2349                  * changes from userspace. It is not enough to just flush
2350                  * the quota file since if blocksize < pagesize, invalidation
2351                  * of the cache could fail because of other unrelated dirty
2352                  * data */
2353                 sync_filesystem(sb);
2354                 invalidate_bdev(sb->s_bdev);
2355         }
2356 
2357         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
2358                 /* We don't want quota and atime on quota files (deadlocks
2359                  * possible) Also nobody should write to the file - we use
2360                  * special IO operations which ignore the immutable bit. */
2361                 inode_lock(inode);
2362                 inode->i_flags |= S_NOQUOTA;
2363                 inode_unlock(inode);
2364                 /*
2365                  * When S_NOQUOTA is set, remove dquot references as no more
2366                  * references can be added
2367                  */
2368                 __dquot_drop(inode);
2369         }
2370 
2371         error = -EIO;
2372         dqopt->files[type] = igrab(inode);
2373         if (!dqopt->files[type])
2374                 goto out_file_flags;
2375         error = -EINVAL;
2376         if (!fmt->qf_ops->check_quota_file(sb, type))
2377                 goto out_file_init;
2378 
2379         dqopt->ops[type] = fmt->qf_ops;
2380         dqopt->info[type].dqi_format = fmt;
2381         dqopt->info[type].dqi_fmt_id = format_id;
2382         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
2383         error = dqopt->ops[type]->read_file_info(sb, type);
2384         if (error < 0)
2385                 goto out_file_init;
2386         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
2387                 spin_lock(&dq_data_lock);
2388                 dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
2389                 spin_unlock(&dq_data_lock);
2390         }
2391         spin_lock(&dq_state_lock);
2392         dqopt->flags |= dquot_state_flag(flags, type);
2393         spin_unlock(&dq_state_lock);
2394 
2395         error = add_dquot_ref(sb, type);
2396         if (error)
2397                 dquot_disable(sb, type, flags);
2398 
2399         return error;
2400 out_file_init:
2401         dqopt->files[type] = NULL;
2402         iput(inode);
2403 out_file_flags:
2404         inode_lock(inode);
2405         inode->i_flags &= ~S_NOQUOTA;
2406         inode_unlock(inode);
2407 out_fmt:
2408         put_quota_format(fmt);
2409 
2410         return error;
2411 }
2412 
2413 /* Reenable quotas on remount RW */
2414 int dquot_resume(struct super_block *sb, int type)
2415 {
2416         struct quota_info *dqopt = sb_dqopt(sb);
2417         struct inode *inode;
2418         int ret = 0, cnt;
2419         unsigned int flags;
2420 
2421         /* s_umount should be held in exclusive mode */
2422         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2423                 up_read(&sb->s_umount);
2424 
2425         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2426                 if (type != -1 && cnt != type)
2427                         continue;
2428                 if (!sb_has_quota_suspended(sb, cnt))
2429                         continue;
2430 
2431                 inode = dqopt->files[cnt];
2432                 dqopt->files[cnt] = NULL;
2433                 spin_lock(&dq_state_lock);
2434                 flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
2435                                                         DQUOT_LIMITS_ENABLED,
2436                                                         cnt);
2437                 dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
2438                 spin_unlock(&dq_state_lock);
2439 
2440                 flags = dquot_generic_flag(flags, cnt);
2441                 ret = vfs_load_quota_inode(inode, cnt,
2442                                 dqopt->info[cnt].dqi_fmt_id, flags);
2443                 iput(inode);
2444         }
2445 
2446         return ret;
2447 }
2448 EXPORT_SYMBOL(dquot_resume);
2449 
2450 int dquot_quota_on(struct super_block *sb, int type, int format_id,
2451                    const struct path *path)
2452 {
2453         int error = security_quota_on(path->dentry);
2454         if (error)
2455                 return error;
2456         /* Quota file not on the same filesystem? */
2457         if (path->dentry->d_sb != sb)
2458                 error = -EXDEV;
2459         else
2460                 error = vfs_load_quota_inode(d_inode(path->dentry), type,
2461                                              format_id, DQUOT_USAGE_ENABLED |
2462                                              DQUOT_LIMITS_ENABLED);
2463         return error;
2464 }
2465 EXPORT_SYMBOL(dquot_quota_on);
2466 
2467 /*
2468  * More powerful function for turning on quotas allowing setting
2469  * of individual quota flags
2470  */
2471 int dquot_enable(struct inode *inode, int type, int format_id,
2472                  unsigned int flags)
2473 {
2474         struct super_block *sb = inode->i_sb;
2475 
2476         /* Just unsuspend quotas? */
2477         BUG_ON(flags & DQUOT_SUSPENDED);
2478         /* s_umount should be held in exclusive mode */
2479         if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
2480                 up_read(&sb->s_umount);
2481 
2482         if (!flags)
2483                 return 0;
2484         /* Just updating flags needed? */
2485         if (sb_has_quota_loaded(sb, type)) {
2486                 if (flags & DQUOT_USAGE_ENABLED &&
2487                     sb_has_quota_usage_enabled(sb, type))
2488                         return -EBUSY;
2489                 if (flags & DQUOT_LIMITS_ENABLED &&
2490                     sb_has_quota_limits_enabled(sb, type))
2491                         return -EBUSY;
2492                 spin_lock(&dq_state_lock);
2493                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
2494                 spin_unlock(&dq_state_lock);
2495                 return 0;
2496         }
2497 
2498         return vfs_load_quota_inode(inode, type, format_id, flags);
2499 }
2500 EXPORT_SYMBOL(dquot_enable);
2501 
2502 /*
2503  * This function is used when filesystem needs to initialize quotas
2504  * during mount time.
2505  */
2506 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
2507                 int format_id, int type)
2508 {
2509         struct dentry *dentry;
2510         int error;
2511 
2512         dentry = lookup_one_len_unlocked(qf_name, sb->s_root, strlen(qf_name));
2513         if (IS_ERR(dentry))
2514                 return PTR_ERR(dentry);
2515 
2516         if (d_really_is_negative(dentry)) {
2517                 error = -ENOENT;
2518                 goto out;
2519         }
2520 
2521         error = security_quota_on(dentry);
2522         if (!error)
2523                 error = vfs_load_quota_inode(d_inode(dentry), type, format_id,
2524                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2525 
2526 out:
2527         dput(dentry);
2528         return error;
2529 }
2530 EXPORT_SYMBOL(dquot_quota_on_mount);
2531 
2532 static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
2533 {
2534         int ret;
2535         int type;
2536         struct quota_info *dqopt = sb_dqopt(sb);
2537 
2538         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2539                 return -ENOSYS;
2540         /* Accounting cannot be turned on while fs is mounted */
2541         flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
2542         if (!flags)
2543                 return -EINVAL;
2544         for (type = 0; type < MAXQUOTAS; type++) {
2545                 if (!(flags & qtype_enforce_flag(type)))
2546                         continue;
2547                 /* Can't enforce without accounting */
2548                 if (!sb_has_quota_usage_enabled(sb, type))
2549                         return -EINVAL;
2550                 ret = dquot_enable(dqopt->files[type], type,
2551                                    dqopt->info[type].dqi_fmt_id,
2552                                    DQUOT_LIMITS_ENABLED);
2553                 if (ret < 0)
2554                         goto out_err;
2555         }
2556         return 0;
2557 out_err:
2558         /* Backout enforcement enablement we already did */
2559         for (type--; type >= 0; type--)  {
2560                 if (flags & qtype_enforce_flag(type))
2561                         dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2562         }
2563         /* Error code translation for better compatibility with XFS */
2564         if (ret == -EBUSY)
2565                 ret = -EEXIST;
2566         return ret;
2567 }
2568 
2569 static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
2570 {
2571         int ret;
2572         int type;
2573         struct quota_info *dqopt = sb_dqopt(sb);
2574 
2575         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
2576                 return -ENOSYS;
2577         /*
2578          * We don't support turning off accounting via quotactl. In principle
2579          * quota infrastructure can do this but filesystems don't expect
2580          * userspace to be able to do it.
2581          */
2582         if (flags &
2583                   (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
2584                 return -EOPNOTSUPP;
2585 
2586         /* Filter out limits not enabled */
2587         for (type = 0; type < MAXQUOTAS; type++)
2588                 if (!sb_has_quota_limits_enabled(sb, type))
2589                         flags &= ~qtype_enforce_flag(type);
2590         /* Nothing left? */
2591         if (!flags)
2592                 return -EEXIST;
2593         for (type = 0; type < MAXQUOTAS; type++) {
2594                 if (flags & qtype_enforce_flag(type)) {
2595                         ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
2596                         if (ret < 0)
2597                                 goto out_err;
2598                 }
2599         }
2600         return 0;
2601 out_err:
2602         /* Backout enforcement disabling we already did */
2603         for (type--; type >= 0; type--)  {
2604                 if (flags & qtype_enforce_flag(type))
2605                         dquot_enable(dqopt->files[type], type,
2606                                      dqopt->info[type].dqi_fmt_id,
2607                                      DQUOT_LIMITS_ENABLED);
2608         }
2609         return ret;
2610 }
2611 
2612 /* Generic routine for getting common part of quota structure */
2613 static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2614 {
2615         struct mem_dqblk *dm = &dquot->dq_dqb;
2616 
2617         memset(di, 0, sizeof(*di));
2618         spin_lock(&dquot->dq_dqb_lock);
2619         di->d_spc_hardlimit = dm->dqb_bhardlimit;
2620         di->d_spc_softlimit = dm->dqb_bsoftlimit;
2621         di->d_ino_hardlimit = dm->dqb_ihardlimit;
2622         di->d_ino_softlimit = dm->dqb_isoftlimit;
2623         di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
2624         di->d_ino_count = dm->dqb_curinodes;
2625         di->d_spc_timer = dm->dqb_btime;
2626         di->d_ino_timer = dm->dqb_itime;
2627         spin_unlock(&dquot->dq_dqb_lock);
2628 }
2629 
2630 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
2631                     struct qc_dqblk *di)
2632 {
2633         struct dquot *dquot;
2634 
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_dqblk);
2644 
2645 int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
2646                          struct qc_dqblk *di)
2647 {
2648         struct dquot *dquot;
2649         int err;
2650 
2651         if (!sb->dq_op->get_next_id)
2652                 return -ENOSYS;
2653         err = sb->dq_op->get_next_id(sb, qid);
2654         if (err < 0)
2655                 return err;
2656         dquot = dqget(sb, *qid);
2657         if (IS_ERR(dquot))
2658                 return PTR_ERR(dquot);
2659         do_get_dqblk(dquot, di);
2660         dqput(dquot);
2661 
2662         return 0;
2663 }
2664 EXPORT_SYMBOL(dquot_get_next_dqblk);
2665 
2666 #define VFS_QC_MASK \
2667         (QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
2668          QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
2669          QC_SPC_TIMER | QC_INO_TIMER)
2670 
2671 /* Generic routine for setting common part of quota structure */
2672 static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
2673 {
2674         struct mem_dqblk *dm = &dquot->dq_dqb;
2675         int check_blim = 0, check_ilim = 0;
2676         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
2677 
2678         if (di->d_fieldmask & ~VFS_QC_MASK)
2679                 return -EINVAL;
2680 
2681         if (((di->d_fieldmask & QC_SPC_SOFT) &&
2682              di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
2683             ((di->d_fieldmask & QC_SPC_HARD) &&
2684              di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
2685             ((di->d_fieldmask & QC_INO_SOFT) &&
2686              (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
2687             ((di->d_fieldmask & QC_INO_HARD) &&
2688              (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
2689                 return -ERANGE;
2690 
2691         spin_lock(&dquot->dq_dqb_lock);
2692         if (di->d_fieldmask & QC_SPACE) {
2693                 dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
2694                 check_blim = 1;
2695                 set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2696         }
2697 
2698         if (di->d_fieldmask & QC_SPC_SOFT)
2699                 dm->dqb_bsoftlimit = di->d_spc_softlimit;
2700         if (di->d_fieldmask & QC_SPC_HARD)
2701                 dm->dqb_bhardlimit = di->d_spc_hardlimit;
2702         if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
2703                 check_blim = 1;
2704                 set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2705         }
2706 
2707         if (di->d_fieldmask & QC_INO_COUNT) {
2708                 dm->dqb_curinodes = di->d_ino_count;
2709                 check_ilim = 1;
2710                 set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2711         }
2712 
2713         if (di->d_fieldmask & QC_INO_SOFT)
2714                 dm->dqb_isoftlimit = di->d_ino_softlimit;
2715         if (di->d_fieldmask & QC_INO_HARD)
2716                 dm->dqb_ihardlimit = di->d_ino_hardlimit;
2717         if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
2718                 check_ilim = 1;
2719                 set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2720         }
2721 
2722         if (di->d_fieldmask & QC_SPC_TIMER) {
2723                 dm->dqb_btime = di->d_spc_timer;
2724                 check_blim = 1;
2725                 set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2726         }
2727 
2728         if (di->d_fieldmask & QC_INO_TIMER) {
2729                 dm->dqb_itime = di->d_ino_timer;
2730                 check_ilim = 1;
2731                 set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2732         }
2733 
2734         if (check_blim) {
2735                 if (!dm->dqb_bsoftlimit ||
2736                     dm->dqb_curspace + dm->dqb_rsvspace <= dm->dqb_bsoftlimit) {
2737                         dm->dqb_btime = 0;
2738                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2739                 } else if (!(di->d_fieldmask & QC_SPC_TIMER))
2740                         /* Set grace only if user hasn't provided his own... */
2741                         dm->dqb_btime = ktime_get_real_seconds() + dqi->dqi_bgrace;
2742         }
2743         if (check_ilim) {
2744                 if (!dm->dqb_isoftlimit ||
2745                     dm->dqb_curinodes <= dm->dqb_isoftlimit) {
2746                         dm->dqb_itime = 0;
2747                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2748                 } else if (!(di->d_fieldmask & QC_INO_TIMER))
2749                         /* Set grace only if user hasn't provided his own... */
2750                         dm->dqb_itime = ktime_get_real_seconds() + dqi->dqi_igrace;
2751         }
2752         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit ||
2753             dm->dqb_isoftlimit)
2754                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2755         else
2756                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2757         spin_unlock(&dquot->dq_dqb_lock);
2758         mark_dquot_dirty(dquot);
2759 
2760         return 0;
2761 }
2762 
2763 int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
2764                   struct qc_dqblk *di)
2765 {
2766         struct dquot *dquot;
2767         int rc;
2768 
2769         dquot = dqget(sb, qid);
2770         if (IS_ERR(dquot)) {
2771                 rc = PTR_ERR(dquot);
2772                 goto out;
2773         }
2774         rc = do_set_dqblk(dquot, di);
2775         dqput(dquot);
2776 out:
2777         return rc;
2778 }
2779 EXPORT_SYMBOL(dquot_set_dqblk);
2780 
2781 /* Generic routine for getting common part of quota file information */
2782 int dquot_get_state(struct super_block *sb, struct qc_state *state)
2783 {
2784         struct mem_dqinfo *mi;
2785         struct qc_type_state *tstate;
2786         struct quota_info *dqopt = sb_dqopt(sb);
2787         int type;
2788 
2789         memset(state, 0, sizeof(*state));
2790         for (type = 0; type < MAXQUOTAS; type++) {
2791                 if (!sb_has_quota_active(sb, type))
2792                         continue;
2793                 tstate = state->s_state + type;
2794                 mi = sb_dqopt(sb)->info + type;
2795                 tstate->flags = QCI_ACCT_ENABLED;
2796                 spin_lock(&dq_data_lock);
2797                 if (mi->dqi_flags & DQF_SYS_FILE)
2798                         tstate->flags |= QCI_SYSFILE;
2799                 if (mi->dqi_flags & DQF_ROOT_SQUASH)
2800                         tstate->flags |= QCI_ROOT_SQUASH;
2801                 if (sb_has_quota_limits_enabled(sb, type))
2802                         tstate->flags |= QCI_LIMITS_ENFORCED;
2803                 tstate->spc_timelimit = mi->dqi_bgrace;
2804                 tstate->ino_timelimit = mi->dqi_igrace;
2805                 tstate->ino = dqopt->files[type]->i_ino;
2806                 tstate->blocks = dqopt->files[type]->i_blocks;
2807                 tstate->nextents = 1;   /* We don't know... */
2808                 spin_unlock(&dq_data_lock);
2809         }
2810         return 0;
2811 }
2812 EXPORT_SYMBOL(dquot_get_state);
2813 
2814 /* Generic routine for setting common part of quota file information */
2815 int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
2816 {
2817         struct mem_dqinfo *mi;
2818         int err = 0;
2819 
2820         if ((ii->i_fieldmask & QC_WARNS_MASK) ||
2821             (ii->i_fieldmask & QC_RT_SPC_TIMER))
2822                 return -EINVAL;
2823         if (!sb_has_quota_active(sb, type))
2824                 return -ESRCH;
2825         mi = sb_dqopt(sb)->info + type;
2826         if (ii->i_fieldmask & QC_FLAGS) {
2827                 if ((ii->i_flags & QCI_ROOT_SQUASH &&
2828                      mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
2829                         return -EINVAL;
2830         }
2831         spin_lock(&dq_data_lock);
2832         if (ii->i_fieldmask & QC_SPC_TIMER)
2833                 mi->dqi_bgrace = ii->i_spc_timelimit;
2834         if (ii->i_fieldmask & QC_INO_TIMER)
2835                 mi->dqi_igrace = ii->i_ino_timelimit;
2836         if (ii->i_fieldmask & QC_FLAGS) {
2837                 if (ii->i_flags & QCI_ROOT_SQUASH)
2838                         mi->dqi_flags |= DQF_ROOT_SQUASH;
2839                 else
2840                         mi->dqi_flags &= ~DQF_ROOT_SQUASH;
2841         }
2842         spin_unlock(&dq_data_lock);
2843         mark_info_dirty(sb, type);
2844         /* Force write to disk */
2845         sb->dq_op->write_info(sb, type);
2846         return err;
2847 }
2848 EXPORT_SYMBOL(dquot_set_dqinfo);
2849 
2850 const struct quotactl_ops dquot_quotactl_sysfile_ops = {
2851         .quota_enable   = dquot_quota_enable,
2852         .quota_disable  = dquot_quota_disable,
2853         .quota_sync     = dquot_quota_sync,
2854         .get_state      = dquot_get_state,
2855         .set_info       = dquot_set_dqinfo,
2856         .get_dqblk      = dquot_get_dqblk,
2857         .get_nextdqblk  = dquot_get_next_dqblk,
2858         .set_dqblk      = dquot_set_dqblk
2859 };
2860 EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
2861 
2862 static int do_proc_dqstats(struct ctl_table *table, int write,
2863                      void __user *buffer, size_t *lenp, loff_t *ppos)
2864 {
2865         unsigned int type = (unsigned long *)table->data - dqstats.stat;
2866         s64 value = percpu_counter_sum(&dqstats.counter[type]);
2867 
2868         /* Filter negative values for non-monotonic counters */
2869         if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
2870                           type == DQST_FREE_DQUOTS))
2871                 value = 0;
2872 
2873         /* Update global table */
2874         dqstats.stat[type] = value;
2875         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
2876 }
2877 
2878 static struct ctl_table fs_dqstats_table[] = {
2879         {
2880                 .procname       = "lookups",
2881                 .data           = &dqstats.stat[DQST_LOOKUPS],
2882                 .maxlen         = sizeof(unsigned long),
2883                 .mode           = 0444,
2884                 .proc_handler   = do_proc_dqstats,
2885         },
2886         {
2887                 .procname       = "drops",
2888                 .data           = &dqstats.stat[DQST_DROPS],
2889                 .maxlen         = sizeof(unsigned long),
2890                 .mode           = 0444,
2891                 .proc_handler   = do_proc_dqstats,
2892         },
2893         {
2894                 .procname       = "reads",
2895                 .data           = &dqstats.stat[DQST_READS],
2896                 .maxlen         = sizeof(unsigned long),
2897                 .mode           = 0444,
2898                 .proc_handler   = do_proc_dqstats,
2899         },
2900         {
2901                 .procname       = "writes",
2902                 .data           = &dqstats.stat[DQST_WRITES],
2903                 .maxlen         = sizeof(unsigned long),
2904                 .mode           = 0444,
2905                 .proc_handler   = do_proc_dqstats,
2906         },
2907         {
2908                 .procname       = "cache_hits",
2909                 .data           = &dqstats.stat[DQST_CACHE_HITS],
2910                 .maxlen         = sizeof(unsigned long),
2911                 .mode           = 0444,
2912                 .proc_handler   = do_proc_dqstats,
2913         },
2914         {
2915                 .procname       = "allocated_dquots",
2916                 .data           = &dqstats.stat[DQST_ALLOC_DQUOTS],
2917                 .maxlen         = sizeof(unsigned long),
2918                 .mode           = 0444,
2919                 .proc_handler   = do_proc_dqstats,
2920         },
2921         {
2922                 .procname       = "free_dquots",
2923                 .data           = &dqstats.stat[DQST_FREE_DQUOTS],
2924                 .maxlen         = sizeof(unsigned long),
2925                 .mode           = 0444,
2926                 .proc_handler   = do_proc_dqstats,
2927         },
2928         {
2929                 .procname       = "syncs",
2930                 .data           = &dqstats.stat[DQST_SYNCS],
2931                 .maxlen         = sizeof(unsigned long),
2932                 .mode           = 0444,
2933                 .proc_handler   = do_proc_dqstats,
2934         },
2935 #ifdef CONFIG_PRINT_QUOTA_WARNING
2936         {
2937                 .procname       = "warnings",
2938                 .data           = &flag_print_warnings,
2939                 .maxlen         = sizeof(int),
2940                 .mode           = 0644,
2941                 .proc_handler   = proc_dointvec,
2942         },
2943 #endif
2944         { },
2945 };
2946 
2947 static struct ctl_table fs_table[] = {
2948         {
2949                 .procname       = "quota",
2950                 .mode           = 0555,
2951                 .child          = fs_dqstats_table,
2952         },
2953         { },
2954 };
2955 
2956 static struct ctl_table sys_table[] = {
2957         {
2958                 .procname       = "fs",
2959                 .mode           = 0555,
2960                 .child          = fs_table,
2961         },
2962         { },
2963 };
2964 
2965 static int __init dquot_init(void)
2966 {
2967         int i, ret;
2968         unsigned long nr_hash, order;
2969 
2970         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2971 
2972         register_sysctl_table(sys_table);
2973 
2974         dquot_cachep = kmem_cache_create("dquot",
2975                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2976                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2977                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2978                         NULL);
2979 
2980         order = 0;
2981         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_KERNEL, order);
2982         if (!dquot_hash)
2983                 panic("Cannot create dquot hash table");
2984 
2985         for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
2986                 ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
2987                 if (ret)
2988                         panic("Cannot create dquot stat counters");
2989         }
2990 
2991         /* Find power-of-two hlist_heads which can fit into allocation */
2992         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2993         dq_hash_bits = 0;
2994         do {
2995                 dq_hash_bits++;
2996         } while (nr_hash >> dq_hash_bits);
2997         dq_hash_bits--;
2998 
2999         nr_hash = 1UL << dq_hash_bits;
3000         dq_hash_mask = nr_hash - 1;
3001         for (i = 0; i < nr_hash; i++)
3002                 INIT_HLIST_HEAD(dquot_hash + i);
3003 
3004         pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
3005                 " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
3006 
3007         if (register_shrinker(&dqcache_shrinker))
3008                 panic("Cannot register dquot shrinker");
3009 
3010         return 0;
3011 }
3012 fs_initcall(dquot_init);
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root/fs/quota/dquot.c

DEFINITIONS
