fs/dquot.c

   1 /*
   2  * Implementation of the diskquota system for the LINUX operating system. QUOTA
   3  * is implemented using the BSD system call interface as the means of
   4  * communication with the user level. This file contains the generic routines
   5  * called by the different filesystems on allocation of an inode or block.
   6  * These routines take care of the administration needed to have a consistent
   7  * diskquota tracking system. The ideas of both user and group quotas are based
   8  * on the Melbourne quota system as used on BSD derived systems. The internal
   9  * implementation is based on one of the several variants of the LINUX
  10  * inode-subsystem with added complexity of the diskquota system.
  11  *
  12  * Author:      Marco van Wieringen <mvw@planets.elm.net>
  13  *
  14  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
  15  *
  16  *              Revised list management to avoid races
  17  *              -- Bill Hawes, <whawes@star.net>, 9/98
  18  *
  19  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
  20  *              As the consequence the locking was moved from dquot_decr_...(),
  21  *              dquot_incr_...() to calling functions.
  22  *              invalidate_dquots() now writes modified dquots.
  23  *              Serialized quota_off() and quota_on() for mount point.
  24  *              Fixed a few bugs in grow_dquots().
  25  *              Fixed deadlock in write_dquot() - we no longer account quotas on
  26  *              quota files
  27  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
  28  *              add_dquot_ref() restarts after blocking
  29  *              Added check for bogus uid and fixed check for group in quotactl.
  30  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
  31  *
  32  *              Used struct list_head instead of own list struct
  33  *              Invalidation of referenced dquots is no longer possible
  34  *              Improved free_dquots list management
  35  *              Quota and i_blocks are now updated in one place to avoid races
  36  *              Warnings are now delayed so we won't block in critical section
  37  *              Write updated not to require dquot lock
  38  *              Jan Kara, <jack@suse.cz>, 9/2000
  39  *
  40  *              Added dynamic quota structure allocation
  41  *              Jan Kara <jack@suse.cz> 12/2000
  42  *
  43  *              Rewritten quota interface. Implemented new quota format and
  44  *              formats registering.
  45  *              Jan Kara, <jack@suse.cz>, 2001,2002
  46  *
  47  *              New SMP locking.
  48  *              Jan Kara, <jack@suse.cz>, 10/2002
  49  *
  50  *              Added journalled quota support, fix lock inversion problems
  51  *              Jan Kara, <jack@suse.cz>, 2003,2004
  52  *
  53  * (C) Copyright 1994 - 1997 Marco van Wieringen
  54  */
  55
  56 #include <linux/errno.h>
  57 #include <linux/kernel.h>
  58 #include <linux/fs.h>
  59 #include <linux/mount.h>
  60 #include <linux/mm.h>
  61 #include <linux/time.h>
  62 #include <linux/types.h>
  63 #include <linux/string.h>
  64 #include <linux/fcntl.h>
  65 #include <linux/stat.h>
  66 #include <linux/tty.h>
  67 #include <linux/file.h>
  68 #include <linux/slab.h>
  69 #include <linux/sysctl.h>
  70 #include <linux/init.h>
  71 #include <linux/module.h>
  72 #include <linux/proc_fs.h>
  73 #include <linux/security.h>
  74 #include <linux/kmod.h>
  75 #include <linux/namei.h>
  76 #include <linux/buffer_head.h>
  77 #include <linux/capability.h>
  78 #include <linux/quotaops.h>
  79 #include <linux/writeback.h> /* for inode_lock, oddly enough.. */
  80 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
  81 #include <net/netlink.h>
  82 #include <net/genetlink.h>
  83 #endif
  84
  85 #include <asm/uaccess.h>
  86
  87 #define __DQUOT_PARANOIA
  88
  89 /*
  90  * There are three quota SMP locks. dq_list_lock protects all lists with quotas
  91  * and quota formats, dqstats structure containing statistics about the lists
  92  * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
  93  * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
  94  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
  95  * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
  96  * modifications of quota state (on quotaon and quotaoff) and readers who care
  97  * about latest values take it as well.
  98  *
  99  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
 100  *   dq_list_lock > dq_state_lock
 101  *
 102  * Note that some things (eg. sb pointer, type, id) doesn't change during
 103  * the life of the dquot structure and so needn't to be protected by a lock
 104  *
 105  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
 106  * operation is just reading pointers from inode (or not using them at all) the
 107  * read lock is enough. If pointers are altered function must hold write lock
 108  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
 109  * for altering the flag i_mutex is also needed).
 110  *
 111  * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
 112  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
 113  * Currently dquot is locked only when it is being read to memory (or space for
 114  * it is being allocated) on the first dqget() and when it is being released on
 115  * the last dqput(). The allocation and release oparations are serialized by
 116  * the dq_lock and by checking the use count in dquot_release().  Write
 117  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
 118  * spinlock to internal buffers before writing.
 119  *
 120  * Lock ordering (including related VFS locks) is the following:
 121  *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
 122  *   dqio_mutex
 123  * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
 124  * dqptr_sem. But filesystem has to count with the fact that functions such as
 125  * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
 126  * from inside a transaction to keep filesystem consistency after a crash. Also
 127  * filesystems usually want to do some IO on dquot from ->mark_dirty which is
 128  * called with dqptr_sem held.
 129  * i_mutex on quota files is special (it's below dqio_mutex)
 130  */
 131
 132 static DEFINE_SPINLOCK(dq_list_lock);
 133 static DEFINE_SPINLOCK(dq_state_lock);
 134 DEFINE_SPINLOCK(dq_data_lock);
 135
 136 static char *quotatypes[] = INITQFNAMES;
 137 static struct quota_format_type *quota_formats; /* List of registered formats */
 138 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
 139
 140 /* SLAB cache for dquot structures */
 141 static struct kmem_cache *dquot_cachep;
 142
 143 int register_quota_format(struct quota_format_type *fmt)
 144 {
 145         spin_lock(&dq_list_lock);
 146         fmt->qf_next = quota_formats;
 147         quota_formats = fmt;
 148         spin_unlock(&dq_list_lock);
 149         return 0;
 150 }
 151
 152 void unregister_quota_format(struct quota_format_type *fmt)
 153 {
 154         struct quota_format_type **actqf;
 155
 156         spin_lock(&dq_list_lock);
 157         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
 158         if (*actqf)
 159                 *actqf = (*actqf)->qf_next;
 160         spin_unlock(&dq_list_lock);
 161 }
 162
 163 static struct quota_format_type *find_quota_format(int id)
 164 {
 165         struct quota_format_type *actqf;
 166
 167         spin_lock(&dq_list_lock);
 168         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 169         if (!actqf || !try_module_get(actqf->qf_owner)) {
 170                 int qm;
 171
 172                 spin_unlock(&dq_list_lock);
 173
 174                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
 175                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
 176                         return NULL;
 177
 178                 spin_lock(&dq_list_lock);
 179                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 180                 if (actqf && !try_module_get(actqf->qf_owner))
 181                         actqf = NULL;
 182         }
 183         spin_unlock(&dq_list_lock);
 184         return actqf;
 185 }
 186
 187 static void put_quota_format(struct quota_format_type *fmt)
 188 {
 189         module_put(fmt->qf_owner);
 190 }
 191
 192 /*
 193  * Dquot List Management:
 194  * The quota code uses three lists for dquot management: the inuse_list,
 195  * free_dquots, and dquot_hash[] array. A single dquot structure may be
 196  * on all three lists, depending on its current state.
 197  *
 198  * All dquots are placed to the end of inuse_list when first created, and this
 199  * list is used for invalidate operation, which must look at every dquot.
 200  *
 201  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 202  * and this list is searched whenever we need an available dquot.  Dquots are
 203  * removed from the list as soon as they are used again, and
 204  * dqstats.free_dquots gives the number of dquots on the list. When
 205  * dquot is invalidated it's completely released from memory.
 206  *
 207  * Dquots with a specific identity (device, type and id) are placed on
 208  * one of the dquot_hash[] hash chains. The provides an efficient search
 209  * mechanism to locate a specific dquot.
 210  */
 211
 212 static LIST_HEAD(inuse_list);
 213 static LIST_HEAD(free_dquots);
 214 static unsigned int dq_hash_bits, dq_hash_mask;
 215 static struct hlist_head *dquot_hash;
 216
 217 struct dqstats dqstats;
 218
 219 static inline unsigned int
 220 hashfn(const struct super_block *sb, unsigned int id, int type)
 221 {
 222         unsigned long tmp;
 223
 224         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
 225         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
 226 }
 227
 228 /*
 229  * Following list functions expect dq_list_lock to be held
 230  */
 231 static inline void insert_dquot_hash(struct dquot *dquot)
 232 {
 233         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
 234         hlist_add_head(&dquot->dq_hash, head);
 235 }
 236
 237 static inline void remove_dquot_hash(struct dquot *dquot)
 238 {
 239         hlist_del_init(&dquot->dq_hash);
 240 }
 241
 242 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
 243 {
 244         struct hlist_node *node;
 245         struct dquot *dquot;
 246
 247         hlist_for_each (node, dquot_hash+hashent) {
 248                 dquot = hlist_entry(node, struct dquot, dq_hash);
 249                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
 250                         return dquot;
 251         }
 252         return NODQUOT;
 253 }
 254
 255 /* Add a dquot to the tail of the free list */
 256 static inline void put_dquot_last(struct dquot *dquot)
 257 {
 258         list_add_tail(&dquot->dq_free, &free_dquots);
 259         dqstats.free_dquots++;
 260 }
 261
 262 static inline void remove_free_dquot(struct dquot *dquot)
 263 {
 264         if (list_empty(&dquot->dq_free))
 265                 return;
 266         list_del_init(&dquot->dq_free);
 267         dqstats.free_dquots--;
 268 }
 269
 270 static inline void put_inuse(struct dquot *dquot)
 271 {
 272         /* We add to the back of inuse list so we don't have to restart
 273          * when traversing this list and we block */
 274         list_add_tail(&dquot->dq_inuse, &inuse_list);
 275         dqstats.allocated_dquots++;
 276 }
 277
 278 static inline void remove_inuse(struct dquot *dquot)
 279 {
 280         dqstats.allocated_dquots--;
 281         list_del(&dquot->dq_inuse);
 282 }
 283 /*
 284  * End of list functions needing dq_list_lock
 285  */
 286
 287 static void wait_on_dquot(struct dquot *dquot)
 288 {
 289         mutex_lock(&dquot->dq_lock);
 290         mutex_unlock(&dquot->dq_lock);
 291 }
 292
 293 static inline int dquot_dirty(struct dquot *dquot)
 294 {
 295         return test_bit(DQ_MOD_B, &dquot->dq_flags);
 296 }
 297
 298 static inline int mark_dquot_dirty(struct dquot *dquot)
 299 {
 300         return dquot->dq_sb->dq_op->mark_dirty(dquot);
 301 }
 302
 303 int dquot_mark_dquot_dirty(struct dquot *dquot)
 304 {
 305         spin_lock(&dq_list_lock);
 306         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
 307                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
 308                                 info[dquot->dq_type].dqi_dirty_list);
 309         spin_unlock(&dq_list_lock);
 310         return 0;
 311 }
 312
 313 /* This function needs dq_list_lock */
 314 static inline int clear_dquot_dirty(struct dquot *dquot)
 315 {
 316         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
 317                 return 0;
 318         list_del_init(&dquot->dq_dirty);
 319         return 1;
 320 }
 321
 322 void mark_info_dirty(struct super_block *sb, int type)
 323 {
 324         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
 325 }
 326 EXPORT_SYMBOL(mark_info_dirty);
 327
 328 /*
 329  *      Read dquot from disk and alloc space for it
 330  */
 331
 332 int dquot_acquire(struct dquot *dquot)
 333 {
 334         int ret = 0, ret2 = 0;
 335         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 336
 337         mutex_lock(&dquot->dq_lock);
 338         mutex_lock(&dqopt->dqio_mutex);
 339         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
 340                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
 341         if (ret < 0)
 342                 goto out_iolock;
 343         set_bit(DQ_READ_B, &dquot->dq_flags);
 344         /* Instantiate dquot if needed */
 345         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
 346                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 347                 /* Write the info if needed */
 348                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 349                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 350                 if (ret < 0)
 351                         goto out_iolock;
 352                 if (ret2 < 0) {
 353                         ret = ret2;
 354                         goto out_iolock;
 355                 }
 356         }
 357         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 358 out_iolock:
 359         mutex_unlock(&dqopt->dqio_mutex);
 360         mutex_unlock(&dquot->dq_lock);
 361         return ret;
 362 }
 363
 364 /*
 365  *      Write dquot to disk
 366  */
 367 int dquot_commit(struct dquot *dquot)
 368 {
 369         int ret = 0, ret2 = 0;
 370         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 371
 372         mutex_lock(&dqopt->dqio_mutex);
 373         spin_lock(&dq_list_lock);
 374         if (!clear_dquot_dirty(dquot)) {
 375                 spin_unlock(&dq_list_lock);
 376                 goto out_sem;
 377         }
 378         spin_unlock(&dq_list_lock);
 379         /* Inactive dquot can be only if there was error during read/init
 380          * => we have better not writing it */
 381         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 382                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 383                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 384                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 385                 if (ret >= 0)
 386                         ret = ret2;
 387         }
 388 out_sem:
 389         mutex_unlock(&dqopt->dqio_mutex);
 390         return ret;
 391 }
 392
 393 /*
 394  *      Release dquot
 395  */
 396 int dquot_release(struct dquot *dquot)
 397 {
 398         int ret = 0, ret2 = 0;
 399         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 400
 401         mutex_lock(&dquot->dq_lock);
 402         /* Check whether we are not racing with some other dqget() */
 403         if (atomic_read(&dquot->dq_count) > 1)
 404                 goto out_dqlock;
 405         mutex_lock(&dqopt->dqio_mutex);
 406         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
 407                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
 408                 /* Write the info */
 409                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 410                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 411                 if (ret >= 0)
 412                         ret = ret2;
 413         }
 414         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 415         mutex_unlock(&dqopt->dqio_mutex);
 416 out_dqlock:
 417         mutex_unlock(&dquot->dq_lock);
 418         return ret;
 419 }
 420
 421 void dquot_destroy(struct dquot *dquot)
 422 {
 423         kmem_cache_free(dquot_cachep, dquot);
 424 }
 425 EXPORT_SYMBOL(dquot_destroy);
 426
 427 static inline void do_destroy_dquot(struct dquot *dquot)
 428 {
 429         dquot->dq_sb->dq_op->destroy_dquot(dquot);
 430 }
 431
 432 /* Invalidate all dquots on the list. Note that this function is called after
 433  * quota is disabled and pointers from inodes removed so there cannot be new
 434  * quota users. There can still be some users of quotas due to inodes being
 435  * just deleted or pruned by prune_icache() (those are not attached to any
 436  * list) or parallel quotactl call. We have to wait for such users.
 437  */
 438 static void invalidate_dquots(struct super_block *sb, int type)
 439 {
 440         struct dquot *dquot, *tmp;
 441
 442 restart:
 443         spin_lock(&dq_list_lock);
 444         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
 445                 if (dquot->dq_sb != sb)
 446                         continue;
 447                 if (dquot->dq_type != type)
 448                         continue;
 449                 /* Wait for dquot users */
 450                 if (atomic_read(&dquot->dq_count)) {
 451                         DEFINE_WAIT(wait);
 452
 453                         atomic_inc(&dquot->dq_count);
 454                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
 455                                         TASK_UNINTERRUPTIBLE);
 456                         spin_unlock(&dq_list_lock);
 457                         /* Once dqput() wakes us up, we know it's time to free
 458                          * the dquot.
 459                          * IMPORTANT: we rely on the fact that there is always
 460                          * at most one process waiting for dquot to free.
 461                          * Otherwise dq_count would be > 1 and we would never
 462                          * wake up.
 463                          */
 464                         if (atomic_read(&dquot->dq_count) > 1)
 465                                 schedule();
 466                         finish_wait(&dquot->dq_wait_unused, &wait);
 467                         dqput(dquot);
 468                         /* At this moment dquot() need not exist (it could be
 469                          * reclaimed by prune_dqcache(). Hence we must
 470                          * restart. */
 471                         goto restart;
 472                 }
 473                 /*
 474                  * Quota now has no users and it has been written on last
 475                  * dqput()
 476                  */
 477                 remove_dquot_hash(dquot);
 478                 remove_free_dquot(dquot);
 479                 remove_inuse(dquot);
 480                 do_destroy_dquot(dquot);
 481         }
 482         spin_unlock(&dq_list_lock);
 483 }
 484
 485 /* Call callback for every active dquot on given filesystem */
 486 int dquot_scan_active(struct super_block *sb,
 487                       int (*fn)(struct dquot *dquot, unsigned long priv),
 488                       unsigned long priv)
 489 {
 490         struct dquot *dquot, *old_dquot = NULL;
 491         int ret = 0;
 492
 493         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
 494         spin_lock(&dq_list_lock);
 495         list_for_each_entry(dquot, &inuse_list, dq_inuse) {
 496                 if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
 497                         continue;
 498                 if (dquot->dq_sb != sb)
 499                         continue;
 500                 /* Now we have active dquot so we can just increase use count */
 501                 atomic_inc(&dquot->dq_count);
 502                 dqstats.lookups++;
 503                 spin_unlock(&dq_list_lock);
 504                 dqput(old_dquot);
 505                 old_dquot = dquot;
 506                 ret = fn(dquot, priv);
 507                 if (ret < 0)
 508                         goto out;
 509                 spin_lock(&dq_list_lock);
 510                 /* We are safe to continue now because our dquot could not
 511                  * be moved out of the inuse list while we hold the reference */
 512         }
 513         spin_unlock(&dq_list_lock);
 514 out:
 515         dqput(old_dquot);
 516         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 517         return ret;
 518 }
 519
 520 int vfs_quota_sync(struct super_block *sb, int type)
 521 {
 522         struct list_head *dirty;
 523         struct dquot *dquot;
 524         struct quota_info *dqopt = sb_dqopt(sb);
 525         int cnt;
 526
 527         mutex_lock(&dqopt->dqonoff_mutex);
 528         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 529                 if (type != -1 && cnt != type)
 530                         continue;
 531                 if (!sb_has_quota_active(sb, cnt))
 532                         continue;
 533                 spin_lock(&dq_list_lock);
 534                 dirty = &dqopt->info[cnt].dqi_dirty_list;
 535                 while (!list_empty(dirty)) {
 536                         dquot = list_first_entry(dirty, struct dquot, dq_dirty);
 537                         /* Dirty and inactive can be only bad dquot... */
 538                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 539                                 clear_dquot_dirty(dquot);
 540                                 continue;
 541                         }
 542                         /* Now we have active dquot from which someone is
 543                          * holding reference so we can safely just increase
 544                          * use count */
 545                         atomic_inc(&dquot->dq_count);
 546                         dqstats.lookups++;
 547                         spin_unlock(&dq_list_lock);
 548                         sb->dq_op->write_dquot(dquot);
 549                         dqput(dquot);
 550                         spin_lock(&dq_list_lock);
 551                 }
 552                 spin_unlock(&dq_list_lock);
 553         }
 554
 555         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 556                 if ((cnt == type || type == -1) && sb_has_quota_active(sb, cnt)
 557                     && info_dirty(&dqopt->info[cnt]))
 558                         sb->dq_op->write_info(sb, cnt);
 559         spin_lock(&dq_list_lock);
 560         dqstats.syncs++;
 561         spin_unlock(&dq_list_lock);
 562         mutex_unlock(&dqopt->dqonoff_mutex);
 563
 564         return 0;
 565 }
 566
 567 /* Free unused dquots from cache */
 568 static void prune_dqcache(int count)
 569 {
 570         struct list_head *head;
 571         struct dquot *dquot;
 572
 573         head = free_dquots.prev;
 574         while (head != &free_dquots && count) {
 575                 dquot = list_entry(head, struct dquot, dq_free);
 576                 remove_dquot_hash(dquot);
 577                 remove_free_dquot(dquot);
 578                 remove_inuse(dquot);
 579                 do_destroy_dquot(dquot);
 580                 count--;
 581                 head = free_dquots.prev;
 582         }
 583 }
 584
 585 /*
 586  * This is called from kswapd when we think we need some
 587  * more memory
 588  */
 589
 590 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
 591 {
 592         if (nr) {
 593                 spin_lock(&dq_list_lock);
 594                 prune_dqcache(nr);
 595                 spin_unlock(&dq_list_lock);
 596         }
 597         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
 598 }
 599
 600 static struct shrinker dqcache_shrinker = {
 601         .shrink = shrink_dqcache_memory,
 602         .seeks = DEFAULT_SEEKS,
 603 };
 604
 605 /*
 606  * Put reference to dquot
 607  * NOTE: If you change this function please check whether dqput_blocks() works right...
 608  */
 609 void dqput(struct dquot *dquot)
 610 {
 611         int ret;
 612
 613         if (!dquot)
 614                 return;
 615 #ifdef __DQUOT_PARANOIA
 616         if (!atomic_read(&dquot->dq_count)) {
 617                 printk("VFS: dqput: trying to free free dquot\n");
 618                 printk("VFS: device %s, dquot of %s %d\n",
 619                         dquot->dq_sb->s_id,
 620                         quotatypes[dquot->dq_type],
 621                         dquot->dq_id);
 622                 BUG();
 623         }
 624 #endif
 625
 626         spin_lock(&dq_list_lock);
 627         dqstats.drops++;
 628         spin_unlock(&dq_list_lock);
 629 we_slept:
 630         spin_lock(&dq_list_lock);
 631         if (atomic_read(&dquot->dq_count) > 1) {
 632                 /* We have more than one user... nothing to do */
 633                 atomic_dec(&dquot->dq_count);
 634                 /* Releasing dquot during quotaoff phase? */
 635                 if (!sb_has_quota_active(dquot->dq_sb, dquot->dq_type) &&
 636                     atomic_read(&dquot->dq_count) == 1)
 637                         wake_up(&dquot->dq_wait_unused);
 638                 spin_unlock(&dq_list_lock);
 639                 return;
 640         }
 641         /* Need to release dquot? */
 642         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
 643                 spin_unlock(&dq_list_lock);
 644                 /* Commit dquot before releasing */
 645                 ret = dquot->dq_sb->dq_op->write_dquot(dquot);
 646                 if (ret < 0) {
 647                         printk(KERN_ERR "VFS: cannot write quota structure on "
 648                                 "device %s (error %d). Quota may get out of "
 649                                 "sync!\n", dquot->dq_sb->s_id, ret);
 650                         /*
 651                          * We clear dirty bit anyway, so that we avoid
 652                          * infinite loop here
 653                          */
 654                         spin_lock(&dq_list_lock);
 655                         clear_dquot_dirty(dquot);
 656                         spin_unlock(&dq_list_lock);
 657                 }
 658                 goto we_slept;
 659         }
 660         /* Clear flag in case dquot was inactive (something bad happened) */
 661         clear_dquot_dirty(dquot);
 662         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 663                 spin_unlock(&dq_list_lock);
 664                 dquot->dq_sb->dq_op->release_dquot(dquot);
 665                 goto we_slept;
 666         }
 667         atomic_dec(&dquot->dq_count);
 668 #ifdef __DQUOT_PARANOIA
 669         /* sanity check */
 670         BUG_ON(!list_empty(&dquot->dq_free));
 671 #endif
 672         put_dquot_last(dquot);
 673         spin_unlock(&dq_list_lock);
 674 }
 675
 676 struct dquot *dquot_alloc(struct super_block *sb, int type)
 677 {
 678         return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
 679 }
 680 EXPORT_SYMBOL(dquot_alloc);
 681
 682 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 683 {
 684         struct dquot *dquot;
 685
 686         dquot = sb->dq_op->alloc_dquot(sb, type);
 687         if(!dquot)
 688                 return NODQUOT;
 689
 690         mutex_init(&dquot->dq_lock);
 691         INIT_LIST_HEAD(&dquot->dq_free);
 692         INIT_LIST_HEAD(&dquot->dq_inuse);
 693         INIT_HLIST_NODE(&dquot->dq_hash);
 694         INIT_LIST_HEAD(&dquot->dq_dirty);
 695         init_waitqueue_head(&dquot->dq_wait_unused);
 696         dquot->dq_sb = sb;
 697         dquot->dq_type = type;
 698         atomic_set(&dquot->dq_count, 1);
 699
 700         return dquot;
 701 }
 702
 703 /*
 704  * Get reference to dquot
 705  *
 706  * Locking is slightly tricky here. We are guarded from parallel quotaoff()
 707  * destroying our dquot by:
 708  *   a) checking for quota flags under dq_list_lock and
 709  *   b) getting a reference to dquot before we release dq_list_lock
 710  */
 711 struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
 712 {
 713         unsigned int hashent = hashfn(sb, id, type);
 714         struct dquot *dquot = NODQUOT, *empty = NODQUOT;
 715
 716         if (!sb_has_quota_active(sb, type))
 717                 return NODQUOT;
 718 we_slept:
 719         spin_lock(&dq_list_lock);
 720         spin_lock(&dq_state_lock);
 721         if (!sb_has_quota_active(sb, type)) {
 722                 spin_unlock(&dq_state_lock);
 723                 spin_unlock(&dq_list_lock);
 724                 goto out;
 725         }
 726         spin_unlock(&dq_state_lock);
 727
 728         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
 729                 if (empty == NODQUOT) {
 730                         spin_unlock(&dq_list_lock);
 731                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
 732                                 schedule();     /* Try to wait for a moment... */
 733                         goto we_slept;
 734                 }
 735                 dquot = empty;
 736                 empty = NODQUOT;
 737                 dquot->dq_id = id;
 738                 /* all dquots go on the inuse_list */
 739                 put_inuse(dquot);
 740                 /* hash it first so it can be found */
 741                 insert_dquot_hash(dquot);
 742                 dqstats.lookups++;
 743                 spin_unlock(&dq_list_lock);
 744         } else {
 745                 if (!atomic_read(&dquot->dq_count))
 746                         remove_free_dquot(dquot);
 747                 atomic_inc(&dquot->dq_count);
 748                 dqstats.cache_hits++;
 749                 dqstats.lookups++;
 750                 spin_unlock(&dq_list_lock);
 751         }
 752         /* Wait for dq_lock - after this we know that either dquot_release() is already
 753          * finished or it will be canceled due to dq_count > 1 test */
 754         wait_on_dquot(dquot);
 755         /* Read the dquot and instantiate it (everything done only if needed) */
 756         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
 757                 dqput(dquot);
 758                 dquot = NODQUOT;
 759                 goto out;
 760         }
 761 #ifdef __DQUOT_PARANOIA
 762         BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
 763 #endif
 764 out:
 765         if (empty)
 766                 do_destroy_dquot(empty);
 767
 768         return dquot;
 769 }
 770
 771 static int dqinit_needed(struct inode *inode, int type)
 772 {
 773         int cnt;
 774
 775         if (IS_NOQUOTA(inode))
 776                 return 0;
 777         if (type != -1)
 778                 return inode->i_dquot[type] == NODQUOT;
 779         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 780                 if (inode->i_dquot[cnt] == NODQUOT)
 781                         return 1;
 782         return 0;
 783 }
 784
 785 /* This routine is guarded by dqonoff_mutex mutex */
 786 static void add_dquot_ref(struct super_block *sb, int type)
 787 {
 788         struct inode *inode, *old_inode = NULL;
 789
 790         spin_lock(&inode_lock);
 791         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 792                 if (!atomic_read(&inode->i_writecount))
 793                         continue;
 794                 if (!dqinit_needed(inode, type))
 795                         continue;
 796                 if (inode->i_state & (I_FREEING|I_WILL_FREE))
 797                         continue;
 798
 799                 __iget(inode);
 800                 spin_unlock(&inode_lock);
 801
 802                 iput(old_inode);
 803                 sb->dq_op->initialize(inode, type);
 804                 /* We hold a reference to 'inode' so it couldn't have been
 805                  * removed from s_inodes list while we dropped the inode_lock.
 806                  * We cannot iput the inode now as we can be holding the last
 807                  * reference and we cannot iput it under inode_lock. So we
 808                  * keep the reference and iput it later. */
 809                 old_inode = inode;
 810                 spin_lock(&inode_lock);
 811         }
 812         spin_unlock(&inode_lock);
 813         iput(old_inode);
 814 }
 815
 816 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
 817 static inline int dqput_blocks(struct dquot *dquot)
 818 {
 819         if (atomic_read(&dquot->dq_count) <= 1)
 820                 return 1;
 821         return 0;
 822 }
 823
 824 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
 825 /* We can't race with anybody because we hold dqptr_sem for writing... */
 826 static int remove_inode_dquot_ref(struct inode *inode, int type,
 827                                   struct list_head *tofree_head)
 828 {
 829         struct dquot *dquot = inode->i_dquot[type];
 830
 831         inode->i_dquot[type] = NODQUOT;
 832         if (dquot != NODQUOT) {
 833                 if (dqput_blocks(dquot)) {
 834 #ifdef __DQUOT_PARANOIA
 835                         if (atomic_read(&dquot->dq_count) != 1)
 836                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
 837 #endif
 838                         spin_lock(&dq_list_lock);
 839                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
 840                         spin_unlock(&dq_list_lock);
 841                         return 1;
 842                 }
 843                 else
 844                         dqput(dquot);   /* We have guaranteed we won't block */
 845         }
 846         return 0;
 847 }
 848
 849 /* Free list of dquots - called from inode.c */
 850 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
 851 static void put_dquot_list(struct list_head *tofree_head)
 852 {
 853         struct list_head *act_head;
 854         struct dquot *dquot;
 855
 856         act_head = tofree_head->next;
 857         /* So now we have dquots on the list... Just free them */
 858         while (act_head != tofree_head) {
 859                 dquot = list_entry(act_head, struct dquot, dq_free);
 860                 act_head = act_head->next;
 861                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
 862                 dqput(dquot);
 863         }
 864 }
 865
 866 static void remove_dquot_ref(struct super_block *sb, int type,
 867                 struct list_head *tofree_head)
 868 {
 869         struct inode *inode;
 870
 871         spin_lock(&inode_lock);
 872         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 873                 if (!IS_NOQUOTA(inode))
 874                         remove_inode_dquot_ref(inode, type, tofree_head);
 875         }
 876         spin_unlock(&inode_lock);
 877 }
 878
 879 /* Gather all references from inodes and drop them */
 880 static void drop_dquot_ref(struct super_block *sb, int type)
 881 {
 882         LIST_HEAD(tofree_head);
 883
 884         if (sb->dq_op) {
 885                 down_write(&sb_dqopt(sb)->dqptr_sem);
 886                 remove_dquot_ref(sb, type, &tofree_head);
 887                 up_write(&sb_dqopt(sb)->dqptr_sem);
 888                 put_dquot_list(&tofree_head);
 889         }
 890 }
 891
 892 static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
 893 {
 894         dquot->dq_dqb.dqb_curinodes += number;
 895 }
 896
 897 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
 898 {
 899         dquot->dq_dqb.dqb_curspace += number;
 900 }
 901
 902 static inline void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
 903 {
 904         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
 905             dquot->dq_dqb.dqb_curinodes >= number)
 906                 dquot->dq_dqb.dqb_curinodes -= number;
 907         else
 908                 dquot->dq_dqb.dqb_curinodes = 0;
 909         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
 910                 dquot->dq_dqb.dqb_itime = (time_t) 0;
 911         clear_bit(DQ_INODES_B, &dquot->dq_flags);
 912 }
 913
 914 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
 915 {
 916         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
 917             dquot->dq_dqb.dqb_curspace >= number)
 918                 dquot->dq_dqb.dqb_curspace -= number;
 919         else
 920                 dquot->dq_dqb.dqb_curspace = 0;
 921         if (dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
 922                 dquot->dq_dqb.dqb_btime = (time_t) 0;
 923         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
 924 }
 925
 926 static int warning_issued(struct dquot *dquot, const int warntype)
 927 {
 928         int flag = (warntype == QUOTA_NL_BHARDWARN ||
 929                 warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
 930                 ((warntype == QUOTA_NL_IHARDWARN ||
 931                 warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
 932
 933         if (!flag)
 934                 return 0;
 935         return test_and_set_bit(flag, &dquot->dq_flags);
 936 }
 937
 938 #ifdef CONFIG_PRINT_QUOTA_WARNING
 939 static int flag_print_warnings = 1;
 940
 941 static inline int need_print_warning(struct dquot *dquot)
 942 {
 943         if (!flag_print_warnings)
 944                 return 0;
 945
 946         switch (dquot->dq_type) {
 947                 case USRQUOTA:
 948                         return current_fsuid() == dquot->dq_id;
 949                 case GRPQUOTA:
 950                         return in_group_p(dquot->dq_id);
 951         }
 952         return 0;
 953 }
 954
 955 /* Print warning to user which exceeded quota */
 956 static void print_warning(struct dquot *dquot, const int warntype)
 957 {
 958         char *msg = NULL;
 959         struct tty_struct *tty;
 960
 961         if (warntype == QUOTA_NL_IHARDBELOW ||
 962             warntype == QUOTA_NL_ISOFTBELOW ||
 963             warntype == QUOTA_NL_BHARDBELOW ||
 964             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
 965                 return;
 966
 967         tty = get_current_tty();
 968         if (!tty)
 969                 return;
 970         tty_write_message(tty, dquot->dq_sb->s_id);
 971         if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
 972                 tty_write_message(tty, ": warning, ");
 973         else
 974                 tty_write_message(tty, ": write failed, ");
 975         tty_write_message(tty, quotatypes[dquot->dq_type]);
 976         switch (warntype) {
 977                 case QUOTA_NL_IHARDWARN:
 978                         msg = " file limit reached.\r\n";
 979                         break;
 980                 case QUOTA_NL_ISOFTLONGWARN:
 981                         msg = " file quota exceeded too long.\r\n";
 982                         break;
 983                 case QUOTA_NL_ISOFTWARN:
 984                         msg = " file quota exceeded.\r\n";
 985                         break;
 986                 case QUOTA_NL_BHARDWARN:
 987                         msg = " block limit reached.\r\n";
 988                         break;
 989                 case QUOTA_NL_BSOFTLONGWARN:
 990                         msg = " block quota exceeded too long.\r\n";
 991                         break;
 992                 case QUOTA_NL_BSOFTWARN:
 993                         msg = " block quota exceeded.\r\n";
 994                         break;
 995         }
 996         tty_write_message(tty, msg);
 997         tty_kref_put(tty);
 998 }
 999 #endif
1000
1001 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
1002
1003 /* Netlink family structure for quota */
1004 static struct genl_family quota_genl_family = {
1005         .id = GENL_ID_GENERATE,
1006         .hdrsize = 0,
1007         .name = "VFS_DQUOT",
1008         .version = 1,
1009         .maxattr = QUOTA_NL_A_MAX,
1010 };
1011
1012 /* Send warning to userspace about user which exceeded quota */
1013 static void send_warning(const struct dquot *dquot, const char warntype)
1014 {
1015         static atomic_t seq;
1016         struct sk_buff *skb;
1017         void *msg_head;
1018         int ret;
1019         int msg_size = 4 * nla_total_size(sizeof(u32)) +
1020                        2 * nla_total_size(sizeof(u64));
1021
1022         /* We have to allocate using GFP_NOFS as we are called from a
1023          * filesystem performing write and thus further recursion into
1024          * the fs to free some data could cause deadlocks. */
1025         skb = genlmsg_new(msg_size, GFP_NOFS);
1026         if (!skb) {
1027                 printk(KERN_ERR
1028                   "VFS: Not enough memory to send quota warning.\n");
1029                 return;
1030         }
1031         msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
1032                         &quota_genl_family, 0, QUOTA_NL_C_WARNING);
1033         if (!msg_head) {
1034                 printk(KERN_ERR
1035                   "VFS: Cannot store netlink header in quota warning.\n");
1036                 goto err_out;
1037         }
1038         ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, dquot->dq_type);
1039         if (ret)
1040                 goto attr_err_out;
1041         ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_id);
1042         if (ret)
1043                 goto attr_err_out;
1044         ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
1045         if (ret)
1046                 goto attr_err_out;
1047         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR,
1048                 MAJOR(dquot->dq_sb->s_dev));
1049         if (ret)
1050                 goto attr_err_out;
1051         ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,
1052                 MINOR(dquot->dq_sb->s_dev));
1053         if (ret)
1054                 goto attr_err_out;
1055         ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
1056         if (ret)
1057                 goto attr_err_out;
1058         genlmsg_end(skb, msg_head);
1059
1060         genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
1061         return;
1062 attr_err_out:
1063         printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
1064 err_out:
1065         kfree_skb(skb);
1066 }
1067 #endif
1068
1069 static inline void flush_warnings(struct dquot * const *dquots, char *warntype)
1070 {
1071         int i;
1072
1073         for (i = 0; i < MAXQUOTAS; i++)
1074                 if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN &&
1075                     !warning_issued(dquots[i], warntype[i])) {
1076 #ifdef CONFIG_PRINT_QUOTA_WARNING
1077                         print_warning(dquots[i], warntype[i]);
1078 #endif
1079 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
1080                         send_warning(dquots[i], warntype[i]);
1081 #endif
1082                 }
1083 }
1084
1085 static inline char ignore_hardlimit(struct dquot *dquot)
1086 {
1087         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
1088
1089         return capable(CAP_SYS_RESOURCE) &&
1090             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
1091 }
1092
1093 /* needs dq_data_lock */
1094 static int check_idq(struct dquot *dquot, qsize_t inodes, char *warntype)
1095 {
1096         *warntype = QUOTA_NL_NOWARN;
1097         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1098             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1099                 return QUOTA_OK;
1100
1101         if (dquot->dq_dqb.dqb_ihardlimit &&
1102            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
1103             !ignore_hardlimit(dquot)) {
1104                 *warntype = QUOTA_NL_IHARDWARN;
1105                 return NO_QUOTA;
1106         }
1107
1108         if (dquot->dq_dqb.dqb_isoftlimit &&
1109            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1110             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
1111             !ignore_hardlimit(dquot)) {
1112                 *warntype = QUOTA_NL_ISOFTLONGWARN;
1113                 return NO_QUOTA;
1114         }
1115
1116         if (dquot->dq_dqb.dqb_isoftlimit &&
1117            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
1118             dquot->dq_dqb.dqb_itime == 0) {
1119                 *warntype = QUOTA_NL_ISOFTWARN;
1120                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1121         }
1122
1123         return QUOTA_OK;
1124 }
1125
1126 /* needs dq_data_lock */
1127 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
1128 {
1129         *warntype = QUOTA_NL_NOWARN;
1130         if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
1131             test_bit(DQ_FAKE_B, &dquot->dq_flags))
1132                 return QUOTA_OK;
1133
1134         if (dquot->dq_dqb.dqb_bhardlimit &&
1135             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bhardlimit &&
1136             !ignore_hardlimit(dquot)) {
1137                 if (!prealloc)
1138                         *warntype = QUOTA_NL_BHARDWARN;
1139                 return NO_QUOTA;
1140         }
1141
1142         if (dquot->dq_dqb.dqb_bsoftlimit &&
1143             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bsoftlimit &&
1144             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
1145             !ignore_hardlimit(dquot)) {
1146                 if (!prealloc)
1147                         *warntype = QUOTA_NL_BSOFTLONGWARN;
1148                 return NO_QUOTA;
1149         }
1150
1151         if (dquot->dq_dqb.dqb_bsoftlimit &&
1152             dquot->dq_dqb.dqb_curspace + space > dquot->dq_dqb.dqb_bsoftlimit &&
1153             dquot->dq_dqb.dqb_btime == 0) {
1154                 if (!prealloc) {
1155                         *warntype = QUOTA_NL_BSOFTWARN;
1156                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1157                 }
1158                 else
1159                         /*
1160                          * We don't allow preallocation to exceed softlimit so exceeding will
1161                          * be always printed
1162                          */
1163                         return NO_QUOTA;
1164         }
1165
1166         return QUOTA_OK;
1167 }
1168
1169 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
1170 {
1171         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1172             dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
1173             !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type))
1174                 return QUOTA_NL_NOWARN;
1175
1176         if (dquot->dq_dqb.dqb_curinodes - inodes <= dquot->dq_dqb.dqb_isoftlimit)
1177                 return QUOTA_NL_ISOFTBELOW;
1178         if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
1179             dquot->dq_dqb.dqb_curinodes - inodes < dquot->dq_dqb.dqb_ihardlimit)
1180                 return QUOTA_NL_IHARDBELOW;
1181         return QUOTA_NL_NOWARN;
1182 }
1183
1184 static int info_bdq_free(struct dquot *dquot, qsize_t space)
1185 {
1186         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
1187             dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)
1188                 return QUOTA_NL_NOWARN;
1189
1190         if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
1191                 return QUOTA_NL_BSOFTBELOW;
1192         if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
1193             dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)
1194                 return QUOTA_NL_BHARDBELOW;
1195         return QUOTA_NL_NOWARN;
1196 }
1197 /*
1198  *      Initialize quota pointers in inode
1199  *      We do things in a bit complicated way but by that we avoid calling
1200  *      dqget() and thus filesystem callbacks under dqptr_sem.
1201  */
1202 int dquot_initialize(struct inode *inode, int type)
1203 {
1204         unsigned int id = 0;
1205         int cnt, ret = 0;
1206         struct dquot *got[MAXQUOTAS] = { NODQUOT, NODQUOT };
1207         struct super_block *sb = inode->i_sb;
1208
1209         /* First test before acquiring mutex - solves deadlocks when we
1210          * re-enter the quota code and are already holding the mutex */
1211         if (IS_NOQUOTA(inode))
1212                 return 0;
1213
1214         /* First get references to structures we might need. */
1215         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1216                 if (type != -1 && cnt != type)
1217                         continue;
1218                 switch (cnt) {
1219                 case USRQUOTA:
1220                         id = inode->i_uid;
1221                         break;
1222                 case GRPQUOTA:
1223                         id = inode->i_gid;
1224                         break;
1225                 }
1226                 got[cnt] = dqget(sb, id, cnt);
1227         }
1228
1229         down_write(&sb_dqopt(sb)->dqptr_sem);
1230         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
1231         if (IS_NOQUOTA(inode))
1232                 goto out_err;
1233         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1234                 if (type != -1 && cnt != type)
1235                         continue;
1236                 /* Avoid races with quotaoff() */
1237                 if (!sb_has_quota_active(sb, cnt))
1238                         continue;
1239                 if (inode->i_dquot[cnt] == NODQUOT) {
1240                         inode->i_dquot[cnt] = got[cnt];
1241                         got[cnt] = NODQUOT;
1242                 }
1243         }
1244 out_err:
1245         up_write(&sb_dqopt(sb)->dqptr_sem);
1246         /* Drop unused references */
1247         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1248                 dqput(got[cnt]);
1249         return ret;
1250 }
1251
1252 /*
1253  *      Release all quotas referenced by inode
1254  */
1255 int dquot_drop(struct inode *inode)
1256 {
1257         int cnt;
1258         struct dquot *put[MAXQUOTAS];
1259
1260         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1261         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1262                 put[cnt] = inode->i_dquot[cnt];
1263                 inode->i_dquot[cnt] = NODQUOT;
1264         }
1265         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1266
1267         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1268                 dqput(put[cnt]);
1269         return 0;
1270 }
1271
1272 /* Wrapper to remove references to quota structures from inode */
1273 void vfs_dq_drop(struct inode *inode)
1274 {
1275         /* Here we can get arbitrary inode from clear_inode() so we have
1276          * to be careful. OTOH we don't need locking as quota operations
1277          * are allowed to change only at mount time */
1278         if (!IS_NOQUOTA(inode) && inode->i_sb && inode->i_sb->dq_op
1279             && inode->i_sb->dq_op->drop) {
1280                 int cnt;
1281                 /* Test before calling to rule out calls from proc and such
1282                  * where we are not allowed to block. Note that this is
1283                  * actually reliable test even without the lock - the caller
1284                  * must assure that nobody can come after the DQUOT_DROP and
1285                  * add quota pointers back anyway */
1286                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1287                         if (inode->i_dquot[cnt] != NODQUOT)
1288                                 break;
1289                 if (cnt < MAXQUOTAS)
1290                         inode->i_sb->dq_op->drop(inode);
1291         }
1292 }
1293
1294 /*
1295  * Following four functions update i_blocks+i_bytes fields and
1296  * quota information (together with appropriate checks)
1297  * NOTE: We absolutely rely on the fact that caller dirties
1298  * the inode (usually macros in quotaops.h care about this) and
1299  * holds a handle for the current transaction so that dquot write and
1300  * inode write go into the same transaction.
1301  */
1302
1303 /*
1304  * This operation can block, but only after everything is updated
1305  */
1306 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1307 {
1308         int cnt, ret = NO_QUOTA;
1309         char warntype[MAXQUOTAS];
1310
1311         /* First test before acquiring mutex - solves deadlocks when we
1312          * re-enter the quota code and are already holding the mutex */
1313         if (IS_NOQUOTA(inode)) {
1314 out_add:
1315                 inode_add_bytes(inode, number);
1316                 return QUOTA_OK;
1317         }
1318         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1319                 warntype[cnt] = QUOTA_NL_NOWARN;
1320
1321         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1322         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1323                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1324                 goto out_add;
1325         }
1326         spin_lock(&dq_data_lock);
1327         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1328                 if (inode->i_dquot[cnt] == NODQUOT)
1329                         continue;
1330                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1331                         goto warn_put_all;
1332         }
1333         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1334                 if (inode->i_dquot[cnt] == NODQUOT)
1335                         continue;
1336                 dquot_incr_space(inode->i_dquot[cnt], number);
1337         }
1338         inode_add_bytes(inode, number);
1339         ret = QUOTA_OK;
1340 warn_put_all:
1341         spin_unlock(&dq_data_lock);
1342         if (ret == QUOTA_OK)
1343                 /* Dirtify all the dquots - this can block when journalling */
1344                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1345                         if (inode->i_dquot[cnt])
1346                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1347         flush_warnings(inode->i_dquot, warntype);
1348         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1349         return ret;
1350 }
1351
1352 /*
1353  * This operation can block, but only after everything is updated
1354  */
1355 int dquot_alloc_inode(const struct inode *inode, qsize_t number)
1356 {
1357         int cnt, ret = NO_QUOTA;
1358         char warntype[MAXQUOTAS];
1359
1360         /* First test before acquiring mutex - solves deadlocks when we
1361          * re-enter the quota code and are already holding the mutex */
1362         if (IS_NOQUOTA(inode))
1363                 return QUOTA_OK;
1364         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1365                 warntype[cnt] = QUOTA_NL_NOWARN;
1366         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1367         if (IS_NOQUOTA(inode)) {
1368                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1369                 return QUOTA_OK;
1370         }
1371         spin_lock(&dq_data_lock);
1372         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1373                 if (inode->i_dquot[cnt] == NODQUOT)
1374                         continue;
1375                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1376                         goto warn_put_all;
1377         }
1378
1379         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1380                 if (inode->i_dquot[cnt] == NODQUOT)
1381                         continue;
1382                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1383         }
1384         ret = QUOTA_OK;
1385 warn_put_all:
1386         spin_unlock(&dq_data_lock);
1387         if (ret == QUOTA_OK)
1388                 /* Dirtify all the dquots - this can block when journalling */
1389                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1390                         if (inode->i_dquot[cnt])
1391                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1392         flush_warnings(inode->i_dquot, warntype);
1393         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1394         return ret;
1395 }
1396
1397 /*
1398  * This operation can block, but only after everything is updated
1399  */
1400 int dquot_free_space(struct inode *inode, qsize_t number)
1401 {
1402         unsigned int cnt;
1403         char warntype[MAXQUOTAS];
1404
1405         /* First test before acquiring mutex - solves deadlocks when we
1406          * re-enter the quota code and are already holding the mutex */
1407         if (IS_NOQUOTA(inode)) {
1408 out_sub:
1409                 inode_sub_bytes(inode, number);
1410                 return QUOTA_OK;
1411         }
1412
1413         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1414         /* Now recheck reliably when holding dqptr_sem */
1415         if (IS_NOQUOTA(inode)) {
1416                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1417                 goto out_sub;
1418         }
1419         spin_lock(&dq_data_lock);
1420         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1421                 if (inode->i_dquot[cnt] == NODQUOT)
1422                         continue;
1423                 warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
1424                 dquot_decr_space(inode->i_dquot[cnt], number);
1425         }
1426         inode_sub_bytes(inode, number);
1427         spin_unlock(&dq_data_lock);
1428         /* Dirtify all the dquots - this can block when journalling */
1429         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1430                 if (inode->i_dquot[cnt])
1431                         mark_dquot_dirty(inode->i_dquot[cnt]);
1432         flush_warnings(inode->i_dquot, warntype);
1433         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1434         return QUOTA_OK;
1435 }
1436
1437 /*
1438  * This operation can block, but only after everything is updated
1439  */
1440 int dquot_free_inode(const struct inode *inode, qsize_t number)
1441 {
1442         unsigned int cnt;
1443         char warntype[MAXQUOTAS];
1444
1445         /* First test before acquiring mutex - solves deadlocks when we
1446          * re-enter the quota code and are already holding the mutex */
1447         if (IS_NOQUOTA(inode))
1448                 return QUOTA_OK;
1449
1450         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1451         /* Now recheck reliably when holding dqptr_sem */
1452         if (IS_NOQUOTA(inode)) {
1453                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1454                 return QUOTA_OK;
1455         }
1456         spin_lock(&dq_data_lock);
1457         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1458                 if (inode->i_dquot[cnt] == NODQUOT)
1459                         continue;
1460                 warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
1461                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1462         }
1463         spin_unlock(&dq_data_lock);
1464         /* Dirtify all the dquots - this can block when journalling */
1465         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1466                 if (inode->i_dquot[cnt])
1467                         mark_dquot_dirty(inode->i_dquot[cnt]);
1468         flush_warnings(inode->i_dquot, warntype);
1469         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1470         return QUOTA_OK;
1471 }
1472
1473 /*
1474  * Transfer the number of inode and blocks from one diskquota to an other.
1475  *
1476  * This operation can block, but only after everything is updated
1477  * A transaction must be started when entering this function.
1478  */
1479 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1480 {
1481         qsize_t space;
1482         struct dquot *transfer_from[MAXQUOTAS];
1483         struct dquot *transfer_to[MAXQUOTAS];
1484         int cnt, ret = QUOTA_OK;
1485         int chuid = iattr->ia_valid & ATTR_UID && inode->i_uid != iattr->ia_uid,
1486             chgid = iattr->ia_valid & ATTR_GID && inode->i_gid != iattr->ia_gid;
1487         char warntype_to[MAXQUOTAS];
1488         char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
1489
1490         /* First test before acquiring mutex - solves deadlocks when we
1491          * re-enter the quota code and are already holding the mutex */
1492         if (IS_NOQUOTA(inode))
1493                 return QUOTA_OK;
1494         /* Initialize the arrays */
1495         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1496                 transfer_from[cnt] = NODQUOT;
1497                 transfer_to[cnt] = NODQUOT;
1498                 warntype_to[cnt] = QUOTA_NL_NOWARN;
1499                 switch (cnt) {
1500                         case USRQUOTA:
1501                                 if (!chuid)
1502                                         continue;
1503                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1504                                 break;
1505                         case GRPQUOTA:
1506                                 if (!chgid)
1507                                         continue;
1508                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1509                                 break;
1510                 }
1511         }
1512
1513         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1514         /* Now recheck reliably when holding dqptr_sem */
1515         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1516                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1517                 goto put_all;
1518         }
1519         spin_lock(&dq_data_lock);
1520         space = inode_get_bytes(inode);
1521         /* Build the transfer_from list and check the limits */
1522         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1523                 if (transfer_to[cnt] == NODQUOT)
1524                         continue;
1525                 transfer_from[cnt] = inode->i_dquot[cnt];
1526                 if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
1527                     NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
1528                     warntype_to + cnt) == NO_QUOTA)
1529                         goto over_quota;
1530         }
1531
1532         /*
1533          * Finally perform the needed transfer from transfer_from to transfer_to
1534          */
1535         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1536                 /*
1537                  * Skip changes for same uid or gid or for turned off quota-type.
1538                  */
1539                 if (transfer_to[cnt] == NODQUOT)
1540                         continue;
1541
1542                 /* Due to IO error we might not have transfer_from[] structure */
1543                 if (transfer_from[cnt]) {
1544                         warntype_from_inodes[cnt] =
1545                                 info_idq_free(transfer_from[cnt], 1);
1546                         warntype_from_space[cnt] =
1547                                 info_bdq_free(transfer_from[cnt], space);
1548                         dquot_decr_inodes(transfer_from[cnt], 1);
1549                         dquot_decr_space(transfer_from[cnt], space);
1550                 }
1551
1552                 dquot_incr_inodes(transfer_to[cnt], 1);
1553                 dquot_incr_space(transfer_to[cnt], space);
1554
1555                 inode->i_dquot[cnt] = transfer_to[cnt];
1556         }
1557         spin_unlock(&dq_data_lock);
1558         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1559
1560         /* Dirtify all the dquots - this can block when journalling */
1561         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1562                 if (transfer_from[cnt])
1563                         mark_dquot_dirty(transfer_from[cnt]);
1564                 if (transfer_to[cnt]) {
1565                         mark_dquot_dirty(transfer_to[cnt]);
1566                         /* The reference we got is transferred to the inode */
1567                         transfer_to[cnt] = NODQUOT;
1568                 }
1569         }
1570 warn_put_all:
1571         flush_warnings(transfer_to, warntype_to);
1572         flush_warnings(transfer_from, warntype_from_inodes);
1573         flush_warnings(transfer_from, warntype_from_space);
1574 put_all:
1575         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1576                 dqput(transfer_from[cnt]);
1577                 dqput(transfer_to[cnt]);
1578         }
1579         return ret;
1580 over_quota:
1581         spin_unlock(&dq_data_lock);
1582         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1583         /* Clear dquot pointers we don't want to dqput() */
1584         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1585                 transfer_from[cnt] = NODQUOT;
1586         ret = NO_QUOTA;
1587         goto warn_put_all;
1588 }
1589
1590 /* Wrapper for transferring ownership of an inode */
1591 int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
1592 {
1593         if (sb_any_quota_active(inode->i_sb) && !IS_NOQUOTA(inode)) {
1594                 vfs_dq_init(inode);
1595                 if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
1596                         return 1;
1597         }
1598         return 0;
1599 }
1600
1601
1602 /*
1603  * Write info of quota file to disk
1604  */
1605 int dquot_commit_info(struct super_block *sb, int type)
1606 {
1607         int ret;
1608         struct quota_info *dqopt = sb_dqopt(sb);
1609
1610         mutex_lock(&dqopt->dqio_mutex);
1611         ret = dqopt->ops[type]->write_file_info(sb, type);
1612         mutex_unlock(&dqopt->dqio_mutex);
1613         return ret;
1614 }
1615
1616 /*
1617  * Definitions of diskquota operations.
1618  */
1619 struct dquot_operations dquot_operations = {
1620         .initialize     = dquot_initialize,
1621         .drop           = dquot_drop,
1622         .alloc_space    = dquot_alloc_space,
1623         .alloc_inode    = dquot_alloc_inode,
1624         .free_space     = dquot_free_space,
1625         .free_inode     = dquot_free_inode,
1626         .transfer       = dquot_transfer,
1627         .write_dquot    = dquot_commit,
1628         .acquire_dquot  = dquot_acquire,
1629         .release_dquot  = dquot_release,
1630         .mark_dirty     = dquot_mark_dquot_dirty,
1631         .write_info     = dquot_commit_info,
1632         .alloc_dquot    = dquot_alloc,
1633         .destroy_dquot  = dquot_destroy,
1634 };
1635
1636 /*
1637  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1638  */
1639 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
1640 {
1641         int cnt, ret = 0;
1642         struct quota_info *dqopt = sb_dqopt(sb);
1643         struct inode *toputinode[MAXQUOTAS];
1644
1645         /* Cannot turn off usage accounting without turning off limits, or
1646          * suspend quotas and simultaneously turn quotas off. */
1647         if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
1648             || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
1649             DQUOT_USAGE_ENABLED)))
1650                 return -EINVAL;
1651
1652         /* We need to serialize quota_off() for device */
1653         mutex_lock(&dqopt->dqonoff_mutex);
1654
1655         /*
1656          * Skip everything if there's nothing to do. We have to do this because
1657          * sometimes we are called when fill_super() failed and calling
1658          * sync_fs() in such cases does no good.
1659          */
1660         if (!sb_any_quota_loaded(sb)) {
1661                 mutex_unlock(&dqopt->dqonoff_mutex);
1662                 return 0;
1663         }
1664         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1665                 toputinode[cnt] = NULL;
1666                 if (type != -1 && cnt != type)
1667                         continue;
1668                 if (!sb_has_quota_loaded(sb, cnt))
1669                         continue;
1670
1671                 if (flags & DQUOT_SUSPENDED) {
1672                         spin_lock(&dq_state_lock);
1673                         dqopt->flags |=
1674                                 dquot_state_flag(DQUOT_SUSPENDED, cnt);
1675                         spin_unlock(&dq_state_lock);
1676                 } else {
1677                         spin_lock(&dq_state_lock);
1678                         dqopt->flags &= ~dquot_state_flag(flags, cnt);
1679                         /* Turning off suspended quotas? */
1680                         if (!sb_has_quota_loaded(sb, cnt) &&
1681                             sb_has_quota_suspended(sb, cnt)) {
1682                                 dqopt->flags &= ~dquot_state_flag(
1683                                                         DQUOT_SUSPENDED, cnt);
1684                                 spin_unlock(&dq_state_lock);
1685                                 iput(dqopt->files[cnt]);
1686                                 dqopt->files[cnt] = NULL;
1687                                 continue;
1688                         }
1689                         spin_unlock(&dq_state_lock);
1690                 }
1691
1692                 /* We still have to keep quota loaded? */
1693                 if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
1694                         continue;
1695
1696                 /* Note: these are blocking operations */
1697                 drop_dquot_ref(sb, cnt);
1698                 invalidate_dquots(sb, cnt);
1699                 /*
1700                  * Now all dquots should be invalidated, all writes done so we should be only
1701                  * users of the info. No locks needed.
1702                  */
1703                 if (info_dirty(&dqopt->info[cnt]))
1704                         sb->dq_op->write_info(sb, cnt);
1705                 if (dqopt->ops[cnt]->free_file_info)
1706                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1707                 put_quota_format(dqopt->info[cnt].dqi_format);
1708
1709                 toputinode[cnt] = dqopt->files[cnt];
1710                 if (!sb_has_quota_loaded(sb, cnt))
1711                         dqopt->files[cnt] = NULL;
1712                 dqopt->info[cnt].dqi_flags = 0;
1713                 dqopt->info[cnt].dqi_igrace = 0;
1714                 dqopt->info[cnt].dqi_bgrace = 0;
1715                 dqopt->ops[cnt] = NULL;
1716         }
1717         mutex_unlock(&dqopt->dqonoff_mutex);
1718
1719         /* Skip syncing and setting flags if quota files are hidden */
1720         if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
1721                 goto put_inodes;
1722
1723         /* Sync the superblock so that buffers with quota data are written to
1724          * disk (and so userspace sees correct data afterwards). */
1725         if (sb->s_op->sync_fs)
1726                 sb->s_op->sync_fs(sb, 1);
1727         sync_blockdev(sb->s_bdev);
1728         /* Now the quota files are just ordinary files and we can set the
1729          * inode flags back. Moreover we discard the pagecache so that
1730          * userspace sees the writes we did bypassing the pagecache. We
1731          * must also discard the blockdev buffers so that we see the
1732          * changes done by userspace on the next quotaon() */
1733         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1734                 if (toputinode[cnt]) {
1735                         mutex_lock(&dqopt->dqonoff_mutex);
1736                         /* If quota was reenabled in the meantime, we have
1737                          * nothing to do */
1738                         if (!sb_has_quota_loaded(sb, cnt)) {
1739                                 mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
1740                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1741                                   S_NOATIME | S_NOQUOTA);
1742                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1743                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1744                                 mark_inode_dirty(toputinode[cnt]);
1745                         }
1746                         mutex_unlock(&dqopt->dqonoff_mutex);
1747                 }
1748         if (sb->s_bdev)
1749                 invalidate_bdev(sb->s_bdev);
1750 put_inodes:
1751         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1752                 if (toputinode[cnt]) {
1753                         /* On remount RO, we keep the inode pointer so that we
1754                          * can reenable quota on the subsequent remount RW. We
1755                          * have to check 'flags' variable and not use sb_has_
1756                          * function because another quotaon / quotaoff could
1757                          * change global state before we got here. We refuse
1758                          * to suspend quotas when there is pending delete on
1759                          * the quota file... */
1760                         if (!(flags & DQUOT_SUSPENDED))
1761                                 iput(toputinode[cnt]);
1762                         else if (!toputinode[cnt]->i_nlink)
1763                                 ret = -EBUSY;
1764                 }
1765         return ret;
1766 }
1767
1768 int vfs_quota_off(struct super_block *sb, int type, int remount)
1769 {
1770         return vfs_quota_disable(sb, type, remount ? DQUOT_SUSPENDED :
1771                                  (DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED));
1772 }
1773
1774 /*
1775  *      Turn quotas on on a device
1776  */
1777
1778 /*
1779  * Helper function to turn quotas on when we already have the inode of
1780  * quota file and no quota information is loaded.
1781  */
1782 static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
1783         unsigned int flags)
1784 {
1785         struct quota_format_type *fmt = find_quota_format(format_id);
1786         struct super_block *sb = inode->i_sb;
1787         struct quota_info *dqopt = sb_dqopt(sb);
1788         int error;
1789         int oldflags = -1;
1790
1791         if (!fmt)
1792                 return -ESRCH;
1793         if (!S_ISREG(inode->i_mode)) {
1794                 error = -EACCES;
1795                 goto out_fmt;
1796         }
1797         if (IS_RDONLY(inode)) {
1798                 error = -EROFS;
1799                 goto out_fmt;
1800         }
1801         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1802                 error = -EINVAL;
1803                 goto out_fmt;
1804         }
1805         /* Usage always has to be set... */
1806         if (!(flags & DQUOT_USAGE_ENABLED)) {
1807                 error = -EINVAL;
1808                 goto out_fmt;
1809         }
1810
1811         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1812                 /* As we bypass the pagecache we must now flush the inode so
1813                  * that we see all the changes from userspace... */
1814                 write_inode_now(inode, 1);
1815                 /* And now flush the block cache so that kernel sees the
1816                  * changes */
1817                 invalidate_bdev(sb->s_bdev);
1818         }
1819         mutex_lock(&inode->i_mutex);
1820         mutex_lock(&dqopt->dqonoff_mutex);
1821         if (sb_has_quota_loaded(sb, type)) {
1822                 error = -EBUSY;
1823                 goto out_lock;
1824         }
1825
1826         if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
1827                 /* We don't want quota and atime on quota files (deadlocks
1828                  * possible) Also nobody should write to the file - we use
1829                  * special IO operations which ignore the immutable bit. */
1830                 down_write(&dqopt->dqptr_sem);
1831                 oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1832                 inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1833                 up_write(&dqopt->dqptr_sem);
1834                 sb->dq_op->drop(inode);
1835         }
1836
1837         error = -EIO;
1838         dqopt->files[type] = igrab(inode);
1839         if (!dqopt->files[type])
1840                 goto out_lock;
1841         error = -EINVAL;
1842         if (!fmt->qf_ops->check_quota_file(sb, type))
1843                 goto out_file_init;
1844
1845         dqopt->ops[type] = fmt->qf_ops;
1846         dqopt->info[type].dqi_format = fmt;
1847         dqopt->info[type].dqi_fmt_id = format_id;
1848         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1849         mutex_lock(&dqopt->dqio_mutex);
1850         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1851                 mutex_unlock(&dqopt->dqio_mutex);
1852                 goto out_file_init;
1853         }
1854         mutex_unlock(&dqopt->dqio_mutex);
1855         mutex_unlock(&inode->i_mutex);
1856         spin_lock(&dq_state_lock);
1857         dqopt->flags |= dquot_state_flag(flags, type);
1858         spin_unlock(&dq_state_lock);
1859
1860         add_dquot_ref(sb, type);
1861         mutex_unlock(&dqopt->dqonoff_mutex);
1862
1863         return 0;
1864
1865 out_file_init:
1866         dqopt->files[type] = NULL;
1867         iput(inode);
1868 out_lock:
1869         mutex_unlock(&dqopt->dqonoff_mutex);
1870         if (oldflags != -1) {
1871                 down_write(&dqopt->dqptr_sem);
1872                 /* Set the flags back (in the case of accidental quotaon()
1873                  * on a wrong file we don't want to mess up the flags) */
1874                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1875                 inode->i_flags |= oldflags;
1876                 up_write(&dqopt->dqptr_sem);
1877         }
1878         mutex_unlock(&inode->i_mutex);
1879 out_fmt:
1880         put_quota_format(fmt);
1881
1882         return error;
1883 }
1884
1885 /* Reenable quotas on remount RW */
1886 static int vfs_quota_on_remount(struct super_block *sb, int type)
1887 {
1888         struct quota_info *dqopt = sb_dqopt(sb);
1889         struct inode *inode;
1890         int ret;
1891         unsigned int flags;
1892
1893         mutex_lock(&dqopt->dqonoff_mutex);
1894         if (!sb_has_quota_suspended(sb, type)) {
1895                 mutex_unlock(&dqopt->dqonoff_mutex);
1896                 return 0;
1897         }
1898         inode = dqopt->files[type];
1899         dqopt->files[type] = NULL;
1900         spin_lock(&dq_state_lock);
1901         flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
1902                                                 DQUOT_LIMITS_ENABLED, type);
1903         dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, type);
1904         spin_unlock(&dq_state_lock);
1905         mutex_unlock(&dqopt->dqonoff_mutex);
1906
1907         flags = dquot_generic_flag(flags, type);
1908         ret = vfs_load_quota_inode(inode, type, dqopt->info[type].dqi_fmt_id,
1909                                    flags);
1910         iput(inode);
1911
1912         return ret;
1913 }
1914
1915 int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
1916                       struct path *path)
1917 {
1918         int error = security_quota_on(path->dentry);
1919         if (error)
1920                 return error;
1921         /* Quota file not on the same filesystem? */
1922         if (path->mnt->mnt_sb != sb)
1923                 error = -EXDEV;
1924         else
1925                 error = vfs_load_quota_inode(path->dentry->d_inode, type,
1926                                              format_id, DQUOT_USAGE_ENABLED |
1927                                              DQUOT_LIMITS_ENABLED);
1928         return error;
1929 }
1930
1931 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
1932                  int remount)
1933 {
1934         struct path path;
1935         int error;
1936
1937         if (remount)
1938                 return vfs_quota_on_remount(sb, type);
1939
1940         error = kern_path(name, LOOKUP_FOLLOW, &path);
1941         if (!error) {
1942                 error = vfs_quota_on_path(sb, type, format_id, &path);
1943                 path_put(&path);
1944         }
1945         return error;
1946 }
1947
1948 /*
1949  * More powerful function for turning on quotas allowing setting
1950  * of individual quota flags
1951  */
1952 int vfs_quota_enable(struct inode *inode, int type, int format_id,
1953                 unsigned int flags)
1954 {
1955         int ret = 0;
1956         struct super_block *sb = inode->i_sb;
1957         struct quota_info *dqopt = sb_dqopt(sb);
1958
1959         /* Just unsuspend quotas? */
1960         if (flags & DQUOT_SUSPENDED)
1961                 return vfs_quota_on_remount(sb, type);
1962         if (!flags)
1963                 return 0;
1964         /* Just updating flags needed? */
1965         if (sb_has_quota_loaded(sb, type)) {
1966                 mutex_lock(&dqopt->dqonoff_mutex);
1967                 /* Now do a reliable test... */
1968                 if (!sb_has_quota_loaded(sb, type)) {
1969                         mutex_unlock(&dqopt->dqonoff_mutex);
1970                         goto load_quota;
1971                 }
1972                 if (flags & DQUOT_USAGE_ENABLED &&
1973                     sb_has_quota_usage_enabled(sb, type)) {
1974                         ret = -EBUSY;
1975                         goto out_lock;
1976                 }
1977                 if (flags & DQUOT_LIMITS_ENABLED &&
1978                     sb_has_quota_limits_enabled(sb, type)) {
1979                         ret = -EBUSY;
1980                         goto out_lock;
1981                 }
1982                 spin_lock(&dq_state_lock);
1983                 sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
1984                 spin_unlock(&dq_state_lock);
1985 out_lock:
1986                 mutex_unlock(&dqopt->dqonoff_mutex);
1987                 return ret;
1988         }
1989
1990 load_quota:
1991         return vfs_load_quota_inode(inode, type, format_id, flags);
1992 }
1993
1994 /*
1995  * This function is used when filesystem needs to initialize quotas
1996  * during mount time.
1997  */
1998 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
1999                 int format_id, int type)
2000 {
2001         struct dentry *dentry;
2002         int error;
2003
2004         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
2005         if (IS_ERR(dentry))
2006                 return PTR_ERR(dentry);
2007
2008         if (!dentry->d_inode) {
2009                 error = -ENOENT;
2010                 goto out;
2011         }
2012
2013         error = security_quota_on(dentry);
2014         if (!error)
2015                 error = vfs_load_quota_inode(dentry->d_inode, type, format_id,
2016                                 DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
2017
2018 out:
2019         dput(dentry);
2020         return error;
2021 }
2022
2023 /* Wrapper to turn on quotas when remounting rw */
2024 int vfs_dq_quota_on_remount(struct super_block *sb)
2025 {
2026         int cnt;
2027         int ret = 0, err;
2028
2029         if (!sb->s_qcop || !sb->s_qcop->quota_on)
2030                 return -ENOSYS;
2031         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
2032                 err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
2033                 if (err < 0 && !ret)
2034                         ret = err;
2035         }
2036         return ret;
2037 }
2038
2039 static inline qsize_t qbtos(qsize_t blocks)
2040 {
2041         return blocks << QIF_DQBLKSIZE_BITS;
2042 }
2043
2044 static inline qsize_t stoqb(qsize_t space)
2045 {
2046         return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
2047 }
2048
2049 /* Generic routine for getting common part of quota structure */
2050 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
2051 {
2052         struct mem_dqblk *dm = &dquot->dq_dqb;
2053
2054         spin_lock(&dq_data_lock);
2055         di->dqb_bhardlimit = stoqb(dm->dqb_bhardlimit);
2056         di->dqb_bsoftlimit = stoqb(dm->dqb_bsoftlimit);
2057         di->dqb_curspace = dm->dqb_curspace;
2058         di->dqb_ihardlimit = dm->dqb_ihardlimit;
2059         di->dqb_isoftlimit = dm->dqb_isoftlimit;
2060         di->dqb_curinodes = dm->dqb_curinodes;
2061         di->dqb_btime = dm->dqb_btime;
2062         di->dqb_itime = dm->dqb_itime;
2063         di->dqb_valid = QIF_ALL;
2064         spin_unlock(&dq_data_lock);
2065 }
2066
2067 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
2068 {
2069         struct dquot *dquot;
2070
2071         dquot = dqget(sb, id, type);
2072         if (dquot == NODQUOT)
2073                 return -ESRCH;
2074         do_get_dqblk(dquot, di);
2075         dqput(dquot);
2076
2077         return 0;
2078 }
2079
2080 /* Generic routine for setting common part of quota structure */
2081 static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
2082 {
2083         struct mem_dqblk *dm = &dquot->dq_dqb;
2084         int check_blim = 0, check_ilim = 0;
2085         struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
2086
2087         if ((di->dqb_valid & QIF_BLIMITS &&
2088              (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
2089               di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
2090             (di->dqb_valid & QIF_ILIMITS &&
2091              (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
2092               di->dqb_isoftlimit > dqi->dqi_maxilimit)))
2093                 return -ERANGE;
2094
2095         spin_lock(&dq_data_lock);
2096         if (di->dqb_valid & QIF_SPACE) {
2097                 dm->dqb_curspace = di->dqb_curspace;
2098                 check_blim = 1;
2099                 __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
2100         }
2101         if (di->dqb_valid & QIF_BLIMITS) {
2102                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
2103                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
2104                 check_blim = 1;
2105                 __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
2106         }
2107         if (di->dqb_valid & QIF_INODES) {
2108                 dm->dqb_curinodes = di->dqb_curinodes;
2109                 check_ilim = 1;
2110                 __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
2111         }
2112         if (di->dqb_valid & QIF_ILIMITS) {
2113                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
2114                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
2115                 check_ilim = 1;
2116                 __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
2117         }
2118         if (di->dqb_valid & QIF_BTIME) {
2119                 dm->dqb_btime = di->dqb_btime;
2120                 check_blim = 1;
2121                 __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
2122         }
2123         if (di->dqb_valid & QIF_ITIME) {
2124                 dm->dqb_itime = di->dqb_itime;
2125                 check_ilim = 1;
2126                 __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
2127         }
2128
2129         if (check_blim) {
2130                 if (!dm->dqb_bsoftlimit || dm->dqb_curspace < dm->dqb_bsoftlimit) {
2131                         dm->dqb_btime = 0;
2132                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
2133                 }
2134                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
2135                         dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
2136         }
2137         if (check_ilim) {
2138                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
2139                         dm->dqb_itime = 0;
2140                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
2141                 }
2142                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
2143                         dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
2144         }
2145         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
2146                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
2147         else
2148                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
2149         spin_unlock(&dq_data_lock);
2150         mark_dquot_dirty(dquot);
2151
2152         return 0;
2153 }
2154
2155 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
2156 {
2157         struct dquot *dquot;
2158         int rc;
2159
2160         dquot = dqget(sb, id, type);
2161         if (!dquot) {
2162                 rc = -ESRCH;
2163                 goto out;
2164         }
2165         rc = do_set_dqblk(dquot, di);
2166         dqput(dquot);
2167 out:
2168         return rc;
2169 }
2170
2171 /* Generic routine for getting common part of quota file information */
2172 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2173 {
2174         struct mem_dqinfo *mi;
2175
2176         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2177         if (!sb_has_quota_active(sb, type)) {
2178                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2179                 return -ESRCH;
2180         }
2181         mi = sb_dqopt(sb)->info + type;
2182         spin_lock(&dq_data_lock);
2183         ii->dqi_bgrace = mi->dqi_bgrace;
2184         ii->dqi_igrace = mi->dqi_igrace;
2185         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
2186         ii->dqi_valid = IIF_ALL;
2187         spin_unlock(&dq_data_lock);
2188         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2189         return 0;
2190 }
2191
2192 /* Generic routine for setting common part of quota file information */
2193 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
2194 {
2195         struct mem_dqinfo *mi;
2196         int err = 0;
2197
2198         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
2199         if (!sb_has_quota_active(sb, type)) {
2200                 err = -ESRCH;
2201                 goto out;
2202         }
2203         mi = sb_dqopt(sb)->info + type;
2204         spin_lock(&dq_data_lock);
2205         if (ii->dqi_valid & IIF_BGRACE)
2206                 mi->dqi_bgrace = ii->dqi_bgrace;
2207         if (ii->dqi_valid & IIF_IGRACE)
2208                 mi->dqi_igrace = ii->dqi_igrace;
2209         if (ii->dqi_valid & IIF_FLAGS)
2210                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
2211         spin_unlock(&dq_data_lock);
2212         mark_info_dirty(sb, type);
2213         /* Force write to disk */
2214         sb->dq_op->write_info(sb, type);
2215 out:
2216         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
2217         return err;
2218 }
2219
2220 struct quotactl_ops vfs_quotactl_ops = {
2221         .quota_on       = vfs_quota_on,
2222         .quota_off      = vfs_quota_off,
2223         .quota_sync     = vfs_quota_sync,
2224         .get_info       = vfs_get_dqinfo,
2225         .set_info       = vfs_set_dqinfo,
2226         .get_dqblk      = vfs_get_dqblk,
2227         .set_dqblk      = vfs_set_dqblk
2228 };
2229
2230 static ctl_table fs_dqstats_table[] = {
2231         {
2232                 .ctl_name       = FS_DQ_LOOKUPS,
2233                 .procname       = "lookups",
2234                 .data           = &dqstats.lookups,
2235                 .maxlen         = sizeof(int),
2236                 .mode           = 0444,
2237                 .proc_handler   = &proc_dointvec,
2238         },
2239         {
2240                 .ctl_name       = FS_DQ_DROPS,
2241                 .procname       = "drops",
2242                 .data           = &dqstats.drops,
2243                 .maxlen         = sizeof(int),
2244                 .mode           = 0444,
2245                 .proc_handler   = &proc_dointvec,
2246         },
2247         {
2248                 .ctl_name       = FS_DQ_READS,
2249                 .procname       = "reads",
2250                 .data           = &dqstats.reads,
2251                 .maxlen         = sizeof(int),
2252                 .mode           = 0444,
2253                 .proc_handler   = &proc_dointvec,
2254         },
2255         {
2256                 .ctl_name       = FS_DQ_WRITES,
2257                 .procname       = "writes",
2258                 .data           = &dqstats.writes,
2259                 .maxlen         = sizeof(int),
2260                 .mode           = 0444,
2261                 .proc_handler   = &proc_dointvec,
2262         },
2263         {
2264                 .ctl_name       = FS_DQ_CACHE_HITS,
2265                 .procname       = "cache_hits",
2266                 .data           = &dqstats.cache_hits,
2267                 .maxlen         = sizeof(int),
2268                 .mode           = 0444,
2269                 .proc_handler   = &proc_dointvec,
2270         },
2271         {
2272                 .ctl_name       = FS_DQ_ALLOCATED,
2273                 .procname       = "allocated_dquots",
2274                 .data           = &dqstats.allocated_dquots,
2275                 .maxlen         = sizeof(int),
2276                 .mode           = 0444,
2277                 .proc_handler   = &proc_dointvec,
2278         },
2279         {
2280                 .ctl_name       = FS_DQ_FREE,
2281                 .procname       = "free_dquots",
2282                 .data           = &dqstats.free_dquots,
2283                 .maxlen         = sizeof(int),
2284                 .mode           = 0444,
2285                 .proc_handler   = &proc_dointvec,
2286         },
2287         {
2288                 .ctl_name       = FS_DQ_SYNCS,
2289                 .procname       = "syncs",
2290                 .data           = &dqstats.syncs,
2291                 .maxlen         = sizeof(int),
2292                 .mode           = 0444,
2293                 .proc_handler   = &proc_dointvec,
2294         },
2295 #ifdef CONFIG_PRINT_QUOTA_WARNING
2296         {
2297                 .ctl_name       = FS_DQ_WARNINGS,
2298                 .procname       = "warnings",
2299                 .data           = &flag_print_warnings,
2300                 .maxlen         = sizeof(int),
2301                 .mode           = 0644,
2302                 .proc_handler   = &proc_dointvec,
2303         },
2304 #endif
2305         { .ctl_name = 0 },
2306 };
2307
2308 static ctl_table fs_table[] = {
2309         {
2310                 .ctl_name       = FS_DQSTATS,
2311                 .procname       = "quota",
2312                 .mode           = 0555,
2313                 .child          = fs_dqstats_table,
2314         },
2315         { .ctl_name = 0 },
2316 };
2317
2318 static ctl_table sys_table[] = {
2319         {
2320                 .ctl_name       = CTL_FS,
2321                 .procname       = "fs",
2322                 .mode           = 0555,
2323                 .child          = fs_table,
2324         },
2325         { .ctl_name = 0 },
2326 };
2327
2328 static int __init dquot_init(void)
2329 {
2330         int i;
2331         unsigned long nr_hash, order;
2332
2333         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
2334
2335         register_sysctl_table(sys_table);
2336
2337         dquot_cachep = kmem_cache_create("dquot",
2338                         sizeof(struct dquot), sizeof(unsigned long) * 4,
2339                         (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
2340                                 SLAB_MEM_SPREAD|SLAB_PANIC),
2341                         NULL);
2342
2343         order = 0;
2344         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
2345         if (!dquot_hash)
2346                 panic("Cannot create dquot hash table");
2347
2348         /* Find power-of-two hlist_heads which can fit into allocation */
2349         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
2350         dq_hash_bits = 0;
2351         do {
2352                 dq_hash_bits++;
2353         } while (nr_hash >> dq_hash_bits);
2354         dq_hash_bits--;
2355
2356         nr_hash = 1UL << dq_hash_bits;
2357         dq_hash_mask = nr_hash - 1;
2358         for (i = 0; i < nr_hash; i++)
2359                 INIT_HLIST_HEAD(dquot_hash + i);
2360
2361         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
2362                         nr_hash, order, (PAGE_SIZE << order));
2363
2364         register_shrinker(&dqcache_shrinker);
2365
2366 #ifdef CONFIG_QUOTA_NETLINK_INTERFACE
2367         if (genl_register_family(&quota_genl_family) != 0)
2368                 printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
2369 #endif
2370
2371         return 0;
2372 }
2373 module_init(dquot_init);
2374
2375 EXPORT_SYMBOL(register_quota_format);
2376 EXPORT_SYMBOL(unregister_quota_format);
2377 EXPORT_SYMBOL(dqstats);
2378 EXPORT_SYMBOL(dq_data_lock);
2379 EXPORT_SYMBOL(vfs_quota_enable);
2380 EXPORT_SYMBOL(vfs_quota_on);
2381 EXPORT_SYMBOL(vfs_quota_on_path);
2382 EXPORT_SYMBOL(vfs_quota_on_mount);
2383 EXPORT_SYMBOL(vfs_quota_disable);
2384 EXPORT_SYMBOL(vfs_quota_off);
2385 EXPORT_SYMBOL(dquot_scan_active);
2386 EXPORT_SYMBOL(vfs_quota_sync);
2387 EXPORT_SYMBOL(vfs_get_dqinfo);
2388 EXPORT_SYMBOL(vfs_set_dqinfo);
2389 EXPORT_SYMBOL(vfs_get_dqblk);
2390 EXPORT_SYMBOL(vfs_set_dqblk);
2391 EXPORT_SYMBOL(dquot_commit);
2392 EXPORT_SYMBOL(dquot_commit_info);
2393 EXPORT_SYMBOL(dquot_acquire);
2394 EXPORT_SYMBOL(dquot_release);
2395 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
2396 EXPORT_SYMBOL(dquot_initialize);
2397 EXPORT_SYMBOL(dquot_drop);
2398 EXPORT_SYMBOL(vfs_dq_drop);
2399 EXPORT_SYMBOL(dqget);
2400 EXPORT_SYMBOL(dqput);
2401 EXPORT_SYMBOL(dquot_alloc_space);
2402 EXPORT_SYMBOL(dquot_alloc_inode);
2403 EXPORT_SYMBOL(dquot_free_space);
2404 EXPORT_SYMBOL(dquot_free_inode);
2405 EXPORT_SYMBOL(dquot_transfer);
2406 EXPORT_SYMBOL(vfs_dq_transfer);
2407 EXPORT_SYMBOL(vfs_dq_quota_on_remount);