SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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  * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
  13  *
  14  * Author:      Marco van Wieringen <mvw@planets.elm.net>
  15  *
  16  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
  17  *
  18  *              Revised list management to avoid races
  19  *              -- Bill Hawes, <whawes@star.net>, 9/98
  20  *
  21  *              Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
  22  *              As the consequence the locking was moved from dquot_decr_...(),
  23  *              dquot_incr_...() to calling functions.
  24  *              invalidate_dquots() now writes modified dquots.
  25  *              Serialized quota_off() and quota_on() for mount point.
  26  *              Fixed a few bugs in grow_dquots().
  27  *              Fixed deadlock in write_dquot() - we no longer account quotas on
  28  *              quota files
  29  *              remove_dquot_ref() moved to inode.c - it now traverses through inodes
  30  *              add_dquot_ref() restarts after blocking
  31  *              Added check for bogus uid and fixed check for group in quotactl.
  32  *              Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
  33  *
  34  *              Used struct list_head instead of own list struct
  35  *              Invalidation of referenced dquots is no longer possible
  36  *              Improved free_dquots list management
  37  *              Quota and i_blocks are now updated in one place to avoid races
  38  *              Warnings are now delayed so we won't block in critical section
  39  *              Write updated not to require dquot lock
  40  *              Jan Kara, <jack@suse.cz>, 9/2000
  41  *
  42  *              Added dynamic quota structure allocation
  43  *              Jan Kara <jack@suse.cz> 12/2000
  44  *
  45  *              Rewritten quota interface. Implemented new quota format and
  46  *              formats registering.
  47  *              Jan Kara, <jack@suse.cz>, 2001,2002
  48  *
  49  *              New SMP locking.
  50  *              Jan Kara, <jack@suse.cz>, 10/2002
  51  *
  52  *              Added journalled quota support, fix lock inversion problems
  53  *              Jan Kara, <jack@suse.cz>, 2003,2004
  54  *
  55  * (C) Copyright 1994 - 1997 Marco van Wieringen
  56  */
  57
  58 #include <linux/errno.h>
  59 #include <linux/kernel.h>
  60 #include <linux/fs.h>
  61 #include <linux/mount.h>
  62 #include <linux/mm.h>
  63 #include <linux/time.h>
  64 #include <linux/types.h>
  65 #include <linux/string.h>
  66 #include <linux/fcntl.h>
  67 #include <linux/stat.h>
  68 #include <linux/tty.h>
  69 #include <linux/file.h>
  70 #include <linux/slab.h>
  71 #include <linux/sysctl.h>
  72 #include <linux/smp_lock.h>
  73 #include <linux/init.h>
  74 #include <linux/module.h>
  75 #include <linux/proc_fs.h>
  76 #include <linux/security.h>
  77 #include <linux/kmod.h>
  78 #include <linux/namei.h>
  79 #include <linux/buffer_head.h>
  80 #include <linux/capability.h>
  81 #include <linux/quotaops.h>
  82
  83 #include <asm/uaccess.h>
  84
  85 #define __DQUOT_PARANOIA
  86
  87 /*
  88  * There are two quota SMP locks. dq_list_lock protects all lists with quotas
  89  * and quota formats and also dqstats structure containing statistics about the
  90  * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
  91  * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
  92  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
  93  * in inode_add_bytes() and inode_sub_bytes().
  94  *
  95  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
  96  *
  97  * Note that some things (eg. sb pointer, type, id) doesn't change during
  98  * the life of the dquot structure and so needn't to be protected by a lock
  99  *
 100  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
 101  * operation is just reading pointers from inode (or not using them at all) the
 102  * read lock is enough. If pointers are altered function must hold write lock
 103  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
 104  * for altering the flag i_mutex is also needed).  If operation is holding
 105  * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
 106  * dqonoff_sem.
 107  * This locking assures that:
 108  *   a) update/access to dquot pointers in inode is serialized
 109  *   b) everyone is guarded against invalidate_dquots()
 110  *
 111  * Each dquot has its dq_lock semaphore. 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 > dqio_sem
 122  * i_mutex on quota files is special (it's below dqio_sem)
 123  */
 124
 125 static DEFINE_SPINLOCK(dq_list_lock);
 126 DEFINE_SPINLOCK(dq_data_lock);
 127
 128 static char *quotatypes[] = INITQFNAMES;
 129 static struct quota_format_type *quota_formats; /* List of registered formats */
 130 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
 131
 132 /* SLAB cache for dquot structures */
 133 static kmem_cache_t *dquot_cachep;
 134
 135 int register_quota_format(struct quota_format_type *fmt)
 136 {
 137         spin_lock(&dq_list_lock);
 138         fmt->qf_next = quota_formats;
 139         quota_formats = fmt;
 140         spin_unlock(&dq_list_lock);
 141         return 0;
 142 }
 143
 144 void unregister_quota_format(struct quota_format_type *fmt)
 145 {
 146         struct quota_format_type **actqf;
 147
 148         spin_lock(&dq_list_lock);
 149         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
 150         if (*actqf)
 151                 *actqf = (*actqf)->qf_next;
 152         spin_unlock(&dq_list_lock);
 153 }
 154
 155 static struct quota_format_type *find_quota_format(int id)
 156 {
 157         struct quota_format_type *actqf;
 158
 159         spin_lock(&dq_list_lock);
 160         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 161         if (!actqf || !try_module_get(actqf->qf_owner)) {
 162                 int qm;
 163
 164                 spin_unlock(&dq_list_lock);
 165
 166                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
 167                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
 168                         return NULL;
 169
 170                 spin_lock(&dq_list_lock);
 171                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 172                 if (actqf && !try_module_get(actqf->qf_owner))
 173                         actqf = NULL;
 174         }
 175         spin_unlock(&dq_list_lock);
 176         return actqf;
 177 }
 178
 179 static void put_quota_format(struct quota_format_type *fmt)
 180 {
 181         module_put(fmt->qf_owner);
 182 }
 183
 184 /*
 185  * Dquot List Management:
 186  * The quota code uses three lists for dquot management: the inuse_list,
 187  * free_dquots, and dquot_hash[] array. A single dquot structure may be
 188  * on all three lists, depending on its current state.
 189  *
 190  * All dquots are placed to the end of inuse_list when first created, and this
 191  * list is used for invalidate operation, which must look at every dquot.
 192  *
 193  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 194  * and this list is searched whenever we need an available dquot.  Dquots are
 195  * removed from the list as soon as they are used again, and
 196  * dqstats.free_dquots gives the number of dquots on the list. When
 197  * dquot is invalidated it's completely released from memory.
 198  *
 199  * Dquots with a specific identity (device, type and id) are placed on
 200  * one of the dquot_hash[] hash chains. The provides an efficient search
 201  * mechanism to locate a specific dquot.
 202  */
 203
 204 static LIST_HEAD(inuse_list);
 205 static LIST_HEAD(free_dquots);
 206 static unsigned int dq_hash_bits, dq_hash_mask;
 207 static struct hlist_head *dquot_hash;
 208
 209 struct dqstats dqstats;
 210
 211 static void dqput(struct dquot *dquot);
 212
 213 static inline unsigned int
 214 hashfn(const struct super_block *sb, unsigned int id, int type)
 215 {
 216         unsigned long tmp;
 217
 218         tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
 219         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
 220 }
 221
 222 /*
 223  * Following list functions expect dq_list_lock to be held
 224  */
 225 static inline void insert_dquot_hash(struct dquot *dquot)
 226 {
 227         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
 228         hlist_add_head(&dquot->dq_hash, head);
 229 }
 230
 231 static inline void remove_dquot_hash(struct dquot *dquot)
 232 {
 233         hlist_del_init(&dquot->dq_hash);
 234 }
 235
 236 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
 237 {
 238         struct hlist_node *node;
 239         struct dquot *dquot;
 240
 241         hlist_for_each (node, dquot_hash+hashent) {
 242                 dquot = hlist_entry(node, struct dquot, dq_hash);
 243                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
 244                         return dquot;
 245         }
 246         return NODQUOT;
 247 }
 248
 249 /* Add a dquot to the tail of the free list */
 250 static inline void put_dquot_last(struct dquot *dquot)
 251 {
 252         list_add(&dquot->dq_free, free_dquots.prev);
 253         dqstats.free_dquots++;
 254 }
 255
 256 static inline void remove_free_dquot(struct dquot *dquot)
 257 {
 258         if (list_empty(&dquot->dq_free))
 259                 return;
 260         list_del_init(&dquot->dq_free);
 261         dqstats.free_dquots--;
 262 }
 263
 264 static inline void put_inuse(struct dquot *dquot)
 265 {
 266         /* We add to the back of inuse list so we don't have to restart
 267          * when traversing this list and we block */
 268         list_add(&dquot->dq_inuse, inuse_list.prev);
 269         dqstats.allocated_dquots++;
 270 }
 271
 272 static inline void remove_inuse(struct dquot *dquot)
 273 {
 274         dqstats.allocated_dquots--;
 275         list_del(&dquot->dq_inuse);
 276 }
 277 /*
 278  * End of list functions needing dq_list_lock
 279  */
 280
 281 static void wait_on_dquot(struct dquot *dquot)
 282 {
 283         down(&dquot->dq_lock);
 284         up(&dquot->dq_lock);
 285 }
 286
 287 #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
 288
 289 int dquot_mark_dquot_dirty(struct dquot *dquot)
 290 {
 291         spin_lock(&dq_list_lock);
 292         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
 293                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
 294                                 info[dquot->dq_type].dqi_dirty_list);
 295         spin_unlock(&dq_list_lock);
 296         return 0;
 297 }
 298
 299 /* This function needs dq_list_lock */
 300 static inline int clear_dquot_dirty(struct dquot *dquot)
 301 {
 302         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
 303                 return 0;
 304         list_del_init(&dquot->dq_dirty);
 305         return 1;
 306 }
 307
 308 void mark_info_dirty(struct super_block *sb, int type)
 309 {
 310         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
 311 }
 312 EXPORT_SYMBOL(mark_info_dirty);
 313
 314 /*
 315  *      Read dquot from disk and alloc space for it
 316  */
 317
 318 int dquot_acquire(struct dquot *dquot)
 319 {
 320         int ret = 0, ret2 = 0;
 321         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 322
 323         down(&dquot->dq_lock);
 324         down(&dqopt->dqio_sem);
 325         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
 326                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
 327         if (ret < 0)
 328                 goto out_iolock;
 329         set_bit(DQ_READ_B, &dquot->dq_flags);
 330         /* Instantiate dquot if needed */
 331         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
 332                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 333                 /* Write the info if needed */
 334                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 335                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 336                 if (ret < 0)
 337                         goto out_iolock;
 338                 if (ret2 < 0) {
 339                         ret = ret2;
 340                         goto out_iolock;
 341                 }
 342         }
 343         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 344 out_iolock:
 345         up(&dqopt->dqio_sem);
 346         up(&dquot->dq_lock);
 347         return ret;
 348 }
 349
 350 /*
 351  *      Write dquot to disk
 352  */
 353 int dquot_commit(struct dquot *dquot)
 354 {
 355         int ret = 0, ret2 = 0;
 356         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 357
 358         down(&dqopt->dqio_sem);
 359         spin_lock(&dq_list_lock);
 360         if (!clear_dquot_dirty(dquot)) {
 361                 spin_unlock(&dq_list_lock);
 362                 goto out_sem;
 363         }
 364         spin_unlock(&dq_list_lock);
 365         /* Inactive dquot can be only if there was error during read/init
 366          * => we have better not writing it */
 367         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 368                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 369                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 370                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 371                 if (ret >= 0)
 372                         ret = ret2;
 373         }
 374 out_sem:
 375         up(&dqopt->dqio_sem);
 376         return ret;
 377 }
 378
 379 /*
 380  *      Release dquot
 381  */
 382 int dquot_release(struct dquot *dquot)
 383 {
 384         int ret = 0, ret2 = 0;
 385         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 386
 387         down(&dquot->dq_lock);
 388         /* Check whether we are not racing with some other dqget() */
 389         if (atomic_read(&dquot->dq_count) > 1)
 390                 goto out_dqlock;
 391         down(&dqopt->dqio_sem);
 392         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
 393                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
 394                 /* Write the info */
 395                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 396                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 397                 if (ret >= 0)
 398                         ret = ret2;
 399         }
 400         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 401         up(&dqopt->dqio_sem);
 402 out_dqlock:
 403         up(&dquot->dq_lock);
 404         return ret;
 405 }
 406
 407 /* Invalidate all dquots on the list. Note that this function is called after
 408  * quota is disabled and pointers from inodes removed so there cannot be new
 409  * quota users. There can still be some users of quotas due to inodes being
 410  * just deleted or pruned by prune_icache() (those are not attached to any
 411  * list). We have to wait for such users.
 412  */
 413 static void invalidate_dquots(struct super_block *sb, int type)
 414 {
 415         struct dquot *dquot, *tmp;
 416
 417 restart:
 418         spin_lock(&dq_list_lock);
 419         list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
 420                 if (dquot->dq_sb != sb)
 421                         continue;
 422                 if (dquot->dq_type != type)
 423                         continue;
 424                 /* Wait for dquot users */
 425                 if (atomic_read(&dquot->dq_count)) {
 426                         DEFINE_WAIT(wait);
 427
 428                         atomic_inc(&dquot->dq_count);
 429                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
 430                                         TASK_UNINTERRUPTIBLE);
 431                         spin_unlock(&dq_list_lock);
 432                         /* Once dqput() wakes us up, we know it's time to free
 433                          * the dquot.
 434                          * IMPORTANT: we rely on the fact that there is always
 435                          * at most one process waiting for dquot to free.
 436                          * Otherwise dq_count would be > 1 and we would never
 437                          * wake up.
 438                          */
 439                         if (atomic_read(&dquot->dq_count) > 1)
 440                                 schedule();
 441                         finish_wait(&dquot->dq_wait_unused, &wait);
 442                         dqput(dquot);
 443                         /* At this moment dquot() need not exist (it could be
 444                          * reclaimed by prune_dqcache(). Hence we must
 445                          * restart. */
 446                         goto restart;
 447                 }
 448                 /*
 449                  * Quota now has no users and it has been written on last
 450                  * dqput()
 451                  */
 452                 remove_dquot_hash(dquot);
 453                 remove_free_dquot(dquot);
 454                 remove_inuse(dquot);
 455                 kmem_cache_free(dquot_cachep, dquot);
 456         }
 457         spin_unlock(&dq_list_lock);
 458 }
 459
 460 int vfs_quota_sync(struct super_block *sb, int type)
 461 {
 462         struct list_head *dirty;
 463         struct dquot *dquot;
 464         struct quota_info *dqopt = sb_dqopt(sb);
 465         int cnt;
 466
 467         down(&dqopt->dqonoff_sem);
 468         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 469                 if (type != -1 && cnt != type)
 470                         continue;
 471                 if (!sb_has_quota_enabled(sb, cnt))
 472                         continue;
 473                 spin_lock(&dq_list_lock);
 474                 dirty = &dqopt->info[cnt].dqi_dirty_list;
 475                 while (!list_empty(dirty)) {
 476                         dquot = list_entry(dirty->next, struct dquot, dq_dirty);
 477                         /* Dirty and inactive can be only bad dquot... */
 478                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 479                                 clear_dquot_dirty(dquot);
 480                                 continue;
 481                         }
 482                         /* Now we have active dquot from which someone is
 483                          * holding reference so we can safely just increase
 484                          * use count */
 485                         atomic_inc(&dquot->dq_count);
 486                         dqstats.lookups++;
 487                         spin_unlock(&dq_list_lock);
 488                         sb->dq_op->write_dquot(dquot);
 489                         dqput(dquot);
 490                         spin_lock(&dq_list_lock);
 491                 }
 492                 spin_unlock(&dq_list_lock);
 493         }
 494
 495         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 496                 if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
 497                         && info_dirty(&dqopt->info[cnt]))
 498                         sb->dq_op->write_info(sb, cnt);
 499         spin_lock(&dq_list_lock);
 500         dqstats.syncs++;
 501         spin_unlock(&dq_list_lock);
 502         up(&dqopt->dqonoff_sem);
 503
 504         return 0;
 505 }
 506
 507 /* Free unused dquots from cache */
 508 static void prune_dqcache(int count)
 509 {
 510         struct list_head *head;
 511         struct dquot *dquot;
 512
 513         head = free_dquots.prev;
 514         while (head != &free_dquots && count) {
 515                 dquot = list_entry(head, struct dquot, dq_free);
 516                 remove_dquot_hash(dquot);
 517                 remove_free_dquot(dquot);
 518                 remove_inuse(dquot);
 519                 kmem_cache_free(dquot_cachep, dquot);
 520                 count--;
 521                 head = free_dquots.prev;
 522         }
 523 }
 524
 525 /*
 526  * This is called from kswapd when we think we need some
 527  * more memory
 528  */
 529
 530 static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
 531 {
 532         if (nr) {
 533                 spin_lock(&dq_list_lock);
 534                 prune_dqcache(nr);
 535                 spin_unlock(&dq_list_lock);
 536         }
 537         return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
 538 }
 539
 540 /*
 541  * Put reference to dquot
 542  * NOTE: If you change this function please check whether dqput_blocks() works right...
 543  * MUST be called with either dqptr_sem or dqonoff_sem held
 544  */
 545 static void dqput(struct dquot *dquot)
 546 {
 547         if (!dquot)
 548                 return;
 549 #ifdef __DQUOT_PARANOIA
 550         if (!atomic_read(&dquot->dq_count)) {
 551                 printk("VFS: dqput: trying to free free dquot\n");
 552                 printk("VFS: device %s, dquot of %s %d\n",
 553                         dquot->dq_sb->s_id,
 554                         quotatypes[dquot->dq_type],
 555                         dquot->dq_id);
 556                 BUG();
 557         }
 558 #endif
 559
 560         spin_lock(&dq_list_lock);
 561         dqstats.drops++;
 562         spin_unlock(&dq_list_lock);
 563 we_slept:
 564         spin_lock(&dq_list_lock);
 565         if (atomic_read(&dquot->dq_count) > 1) {
 566                 /* We have more than one user... nothing to do */
 567                 atomic_dec(&dquot->dq_count);
 568                 /* Releasing dquot during quotaoff phase? */
 569                 if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
 570                     atomic_read(&dquot->dq_count) == 1)
 571                         wake_up(&dquot->dq_wait_unused);
 572                 spin_unlock(&dq_list_lock);
 573                 return;
 574         }
 575         /* Need to release dquot? */
 576         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
 577                 spin_unlock(&dq_list_lock);
 578                 /* Commit dquot before releasing */
 579                 dquot->dq_sb->dq_op->write_dquot(dquot);
 580                 goto we_slept;
 581         }
 582         /* Clear flag in case dquot was inactive (something bad happened) */
 583         clear_dquot_dirty(dquot);
 584         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 585                 spin_unlock(&dq_list_lock);
 586                 dquot->dq_sb->dq_op->release_dquot(dquot);
 587                 goto we_slept;
 588         }
 589         atomic_dec(&dquot->dq_count);
 590 #ifdef __DQUOT_PARANOIA
 591         /* sanity check */
 592         if (!list_empty(&dquot->dq_free))
 593                 BUG();
 594 #endif
 595         put_dquot_last(dquot);
 596         spin_unlock(&dq_list_lock);
 597 }
 598
 599 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 600 {
 601         struct dquot *dquot;
 602
 603         dquot = kmem_cache_alloc(dquot_cachep, SLAB_NOFS);
 604         if(!dquot)
 605                 return NODQUOT;
 606
 607         memset((caddr_t)dquot, 0, sizeof(struct dquot));
 608         sema_init(&dquot->dq_lock, 1);
 609         INIT_LIST_HEAD(&dquot->dq_free);
 610         INIT_LIST_HEAD(&dquot->dq_inuse);
 611         INIT_HLIST_NODE(&dquot->dq_hash);
 612         INIT_LIST_HEAD(&dquot->dq_dirty);
 613         init_waitqueue_head(&dquot->dq_wait_unused);
 614         dquot->dq_sb = sb;
 615         dquot->dq_type = type;
 616         atomic_set(&dquot->dq_count, 1);
 617
 618         return dquot;
 619 }
 620
 621 /*
 622  * Get reference to dquot
 623  * MUST be called with either dqptr_sem or dqonoff_sem held
 624  */
 625 static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
 626 {
 627         unsigned int hashent = hashfn(sb, id, type);
 628         struct dquot *dquot, *empty = NODQUOT;
 629
 630         if (!sb_has_quota_enabled(sb, type))
 631                 return NODQUOT;
 632 we_slept:
 633         spin_lock(&dq_list_lock);
 634         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
 635                 if (empty == NODQUOT) {
 636                         spin_unlock(&dq_list_lock);
 637                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
 638                                 schedule();     /* Try to wait for a moment... */
 639                         goto we_slept;
 640                 }
 641                 dquot = empty;
 642                 dquot->dq_id = id;
 643                 /* all dquots go on the inuse_list */
 644                 put_inuse(dquot);
 645                 /* hash it first so it can be found */
 646                 insert_dquot_hash(dquot);
 647                 dqstats.lookups++;
 648                 spin_unlock(&dq_list_lock);
 649         } else {
 650                 if (!atomic_read(&dquot->dq_count))
 651                         remove_free_dquot(dquot);
 652                 atomic_inc(&dquot->dq_count);
 653                 dqstats.cache_hits++;
 654                 dqstats.lookups++;
 655                 spin_unlock(&dq_list_lock);
 656                 if (empty)
 657                         kmem_cache_free(dquot_cachep, empty);
 658         }
 659         /* Wait for dq_lock - after this we know that either dquot_release() is already
 660          * finished or it will be canceled due to dq_count > 1 test */
 661         wait_on_dquot(dquot);
 662         /* Read the dquot and instantiate it (everything done only if needed) */
 663         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
 664                 dqput(dquot);
 665                 return NODQUOT;
 666         }
 667 #ifdef __DQUOT_PARANOIA
 668         if (!dquot->dq_sb)      /* Has somebody invalidated entry under us? */
 669                 BUG();
 670 #endif
 671
 672         return dquot;
 673 }
 674
 675 static int dqinit_needed(struct inode *inode, int type)
 676 {
 677         int cnt;
 678
 679         if (IS_NOQUOTA(inode))
 680                 return 0;
 681         if (type != -1)
 682                 return inode->i_dquot[type] == NODQUOT;
 683         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 684                 if (inode->i_dquot[cnt] == NODQUOT)
 685                         return 1;
 686         return 0;
 687 }
 688
 689 /* This routine is guarded by dqonoff_sem semaphore */
 690 static void add_dquot_ref(struct super_block *sb, int type)
 691 {
 692         struct list_head *p;
 693
 694 restart:
 695         file_list_lock();
 696         list_for_each(p, &sb->s_files) {
 697                 struct file *filp = list_entry(p, struct file, f_u.fu_list);
 698                 struct inode *inode = filp->f_dentry->d_inode;
 699                 if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
 700                         struct dentry *dentry = dget(filp->f_dentry);
 701                         file_list_unlock();
 702                         sb->dq_op->initialize(inode, type);
 703                         dput(dentry);
 704                         /* As we may have blocked we had better restart... */
 705                         goto restart;
 706                 }
 707         }
 708         file_list_unlock();
 709 }
 710
 711 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
 712 static inline int dqput_blocks(struct dquot *dquot)
 713 {
 714         if (atomic_read(&dquot->dq_count) <= 1)
 715                 return 1;
 716         return 0;
 717 }
 718
 719 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
 720 /* We can't race with anybody because we hold dqptr_sem for writing... */
 721 int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
 722 {
 723         struct dquot *dquot = inode->i_dquot[type];
 724
 725         inode->i_dquot[type] = NODQUOT;
 726         if (dquot != NODQUOT) {
 727                 if (dqput_blocks(dquot)) {
 728 #ifdef __DQUOT_PARANOIA
 729                         if (atomic_read(&dquot->dq_count) != 1)
 730                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
 731 #endif
 732                         spin_lock(&dq_list_lock);
 733                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
 734                         spin_unlock(&dq_list_lock);
 735                         return 1;
 736                 }
 737                 else
 738                         dqput(dquot);   /* We have guaranteed we won't block */
 739         }
 740         return 0;
 741 }
 742
 743 /* Free list of dquots - called from inode.c */
 744 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
 745 static void put_dquot_list(struct list_head *tofree_head)
 746 {
 747         struct list_head *act_head;
 748         struct dquot *dquot;
 749
 750         act_head = tofree_head->next;
 751         /* So now we have dquots on the list... Just free them */
 752         while (act_head != tofree_head) {
 753                 dquot = list_entry(act_head, struct dquot, dq_free);
 754                 act_head = act_head->next;
 755                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
 756                 dqput(dquot);
 757         }
 758 }
 759
 760 /* Gather all references from inodes and drop them */
 761 static void drop_dquot_ref(struct super_block *sb, int type)
 762 {
 763         LIST_HEAD(tofree_head);
 764
 765         down_write(&sb_dqopt(sb)->dqptr_sem);
 766         remove_dquot_ref(sb, type, &tofree_head);
 767         up_write(&sb_dqopt(sb)->dqptr_sem);
 768         put_dquot_list(&tofree_head);
 769 }
 770
 771 static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
 772 {
 773         dquot->dq_dqb.dqb_curinodes += number;
 774 }
 775
 776 static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
 777 {
 778         dquot->dq_dqb.dqb_curspace += number;
 779 }
 780
 781 static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
 782 {
 783         if (dquot->dq_dqb.dqb_curinodes > number)
 784                 dquot->dq_dqb.dqb_curinodes -= number;
 785         else
 786                 dquot->dq_dqb.dqb_curinodes = 0;
 787         if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
 788                 dquot->dq_dqb.dqb_itime = (time_t) 0;
 789         clear_bit(DQ_INODES_B, &dquot->dq_flags);
 790 }
 791
 792 static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
 793 {
 794         if (dquot->dq_dqb.dqb_curspace > number)
 795                 dquot->dq_dqb.dqb_curspace -= number;
 796         else
 797                 dquot->dq_dqb.dqb_curspace = 0;
 798         if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
 799                 dquot->dq_dqb.dqb_btime = (time_t) 0;
 800         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
 801 }
 802
 803 static int flag_print_warnings = 1;
 804
 805 static inline int need_print_warning(struct dquot *dquot)
 806 {
 807         if (!flag_print_warnings)
 808                 return 0;
 809
 810         switch (dquot->dq_type) {
 811                 case USRQUOTA:
 812                         return current->fsuid == dquot->dq_id;
 813                 case GRPQUOTA:
 814                         return in_group_p(dquot->dq_id);
 815         }
 816         return 0;
 817 }
 818
 819 /* Values of warnings */
 820 #define NOWARN 0
 821 #define IHARDWARN 1
 822 #define ISOFTLONGWARN 2
 823 #define ISOFTWARN 3
 824 #define BHARDWARN 4
 825 #define BSOFTLONGWARN 5
 826 #define BSOFTWARN 6
 827
 828 /* Print warning to user which exceeded quota */
 829 static void print_warning(struct dquot *dquot, const char warntype)
 830 {
 831         char *msg = NULL;
 832         int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
 833           ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
 834
 835         if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
 836                 return;
 837
 838         tty_write_message(current->signal->tty, dquot->dq_sb->s_id);
 839         if (warntype == ISOFTWARN || warntype == BSOFTWARN)
 840                 tty_write_message(current->signal->tty, ": warning, ");
 841         else
 842                 tty_write_message(current->signal->tty, ": write failed, ");
 843         tty_write_message(current->signal->tty, quotatypes[dquot->dq_type]);
 844         switch (warntype) {
 845                 case IHARDWARN:
 846                         msg = " file limit reached.\r\n";
 847                         break;
 848                 case ISOFTLONGWARN:
 849                         msg = " file quota exceeded too long.\r\n";
 850                         break;
 851                 case ISOFTWARN:
 852                         msg = " file quota exceeded.\r\n";
 853                         break;
 854                 case BHARDWARN:
 855                         msg = " block limit reached.\r\n";
 856                         break;
 857                 case BSOFTLONGWARN:
 858                         msg = " block quota exceeded too long.\r\n";
 859                         break;
 860                 case BSOFTWARN:
 861                         msg = " block quota exceeded.\r\n";
 862                         break;
 863         }
 864         tty_write_message(current->signal->tty, msg);
 865 }
 866
 867 static inline void flush_warnings(struct dquot **dquots, char *warntype)
 868 {
 869         int i;
 870
 871         for (i = 0; i < MAXQUOTAS; i++)
 872                 if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
 873                         print_warning(dquots[i], warntype[i]);
 874 }
 875
 876 static inline char ignore_hardlimit(struct dquot *dquot)
 877 {
 878         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
 879
 880         return capable(CAP_SYS_RESOURCE) &&
 881             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
 882 }
 883
 884 /* needs dq_data_lock */
 885 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
 886 {
 887         *warntype = NOWARN;
 888         if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
 889                 return QUOTA_OK;
 890
 891         if (dquot->dq_dqb.dqb_ihardlimit &&
 892            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
 893             !ignore_hardlimit(dquot)) {
 894                 *warntype = IHARDWARN;
 895                 return NO_QUOTA;
 896         }
 897
 898         if (dquot->dq_dqb.dqb_isoftlimit &&
 899            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
 900             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
 901             !ignore_hardlimit(dquot)) {
 902                 *warntype = ISOFTLONGWARN;
 903                 return NO_QUOTA;
 904         }
 905
 906         if (dquot->dq_dqb.dqb_isoftlimit &&
 907            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
 908             dquot->dq_dqb.dqb_itime == 0) {
 909                 *warntype = ISOFTWARN;
 910                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
 911         }
 912
 913         return QUOTA_OK;
 914 }
 915
 916 /* needs dq_data_lock */
 917 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
 918 {
 919         *warntype = 0;
 920         if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
 921                 return QUOTA_OK;
 922
 923         if (dquot->dq_dqb.dqb_bhardlimit &&
 924            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
 925             !ignore_hardlimit(dquot)) {
 926                 if (!prealloc)
 927                         *warntype = BHARDWARN;
 928                 return NO_QUOTA;
 929         }
 930
 931         if (dquot->dq_dqb.dqb_bsoftlimit &&
 932            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
 933             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
 934             !ignore_hardlimit(dquot)) {
 935                 if (!prealloc)
 936                         *warntype = BSOFTLONGWARN;
 937                 return NO_QUOTA;
 938         }
 939
 940         if (dquot->dq_dqb.dqb_bsoftlimit &&
 941            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
 942             dquot->dq_dqb.dqb_btime == 0) {
 943                 if (!prealloc) {
 944                         *warntype = BSOFTWARN;
 945                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
 946                 }
 947                 else
 948                         /*
 949                          * We don't allow preallocation to exceed softlimit so exceeding will
 950                          * be always printed
 951                          */
 952                         return NO_QUOTA;
 953         }
 954
 955         return QUOTA_OK;
 956 }
 957
 958 /*
 959  *      Initialize quota pointers in inode
 960  *      Transaction must be started at entry
 961  */
 962 int dquot_initialize(struct inode *inode, int type)
 963 {
 964         unsigned int id = 0;
 965         int cnt, ret = 0;
 966
 967         /* First test before acquiring semaphore - solves deadlocks when we
 968          * re-enter the quota code and are already holding the semaphore */
 969         if (IS_NOQUOTA(inode))
 970                 return 0;
 971         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 972         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
 973         if (IS_NOQUOTA(inode))
 974                 goto out_err;
 975         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 976                 if (type != -1 && cnt != type)
 977                         continue;
 978                 if (inode->i_dquot[cnt] == NODQUOT) {
 979                         switch (cnt) {
 980                                 case USRQUOTA:
 981                                         id = inode->i_uid;
 982                                         break;
 983                                 case GRPQUOTA:
 984                                         id = inode->i_gid;
 985                                         break;
 986                         }
 987                         inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
 988                 }
 989         }
 990 out_err:
 991         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 992         return ret;
 993 }
 994
 995 /*
 996  *      Release all quotas referenced by inode
 997  *      Transaction must be started at an entry
 998  */
 999 int dquot_drop(struct inode *inode)
1000 {
1001         int cnt;
1002
1003         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1004         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1005                 if (inode->i_dquot[cnt] != NODQUOT) {
1006                         dqput(inode->i_dquot[cnt]);
1007                         inode->i_dquot[cnt] = NODQUOT;
1008                 }
1009         }
1010         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1011         return 0;
1012 }
1013
1014 /*
1015  * Following four functions update i_blocks+i_bytes fields and
1016  * quota information (together with appropriate checks)
1017  * NOTE: We absolutely rely on the fact that caller dirties
1018  * the inode (usually macros in quotaops.h care about this) and
1019  * holds a handle for the current transaction so that dquot write and
1020  * inode write go into the same transaction.
1021  */
1022
1023 /*
1024  * This operation can block, but only after everything is updated
1025  */
1026 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
1027 {
1028         int cnt, ret = NO_QUOTA;
1029         char warntype[MAXQUOTAS];
1030
1031         /* First test before acquiring semaphore - solves deadlocks when we
1032          * re-enter the quota code and are already holding the semaphore */
1033         if (IS_NOQUOTA(inode)) {
1034 out_add:
1035                 inode_add_bytes(inode, number);
1036                 return QUOTA_OK;
1037         }
1038         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1039                 warntype[cnt] = NOWARN;
1040
1041         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1042         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1043                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1044                 goto out_add;
1045         }
1046         spin_lock(&dq_data_lock);
1047         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1048                 if (inode->i_dquot[cnt] == NODQUOT)
1049                         continue;
1050                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1051                         goto warn_put_all;
1052         }
1053         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1054                 if (inode->i_dquot[cnt] == NODQUOT)
1055                         continue;
1056                 dquot_incr_space(inode->i_dquot[cnt], number);
1057         }
1058         inode_add_bytes(inode, number);
1059         ret = QUOTA_OK;
1060 warn_put_all:
1061         spin_unlock(&dq_data_lock);
1062         if (ret == QUOTA_OK)
1063                 /* Dirtify all the dquots - this can block when journalling */
1064                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1065                         if (inode->i_dquot[cnt])
1066                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1067         flush_warnings(inode->i_dquot, warntype);
1068         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1069         return ret;
1070 }
1071
1072 /*
1073  * This operation can block, but only after everything is updated
1074  */
1075 int dquot_alloc_inode(const struct inode *inode, unsigned long number)
1076 {
1077         int cnt, ret = NO_QUOTA;
1078         char warntype[MAXQUOTAS];
1079
1080         /* First test before acquiring semaphore - solves deadlocks when we
1081          * re-enter the quota code and are already holding the semaphore */
1082         if (IS_NOQUOTA(inode))
1083                 return QUOTA_OK;
1084         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1085                 warntype[cnt] = NOWARN;
1086         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1087         if (IS_NOQUOTA(inode)) {
1088                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1089                 return QUOTA_OK;
1090         }
1091         spin_lock(&dq_data_lock);
1092         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1093                 if (inode->i_dquot[cnt] == NODQUOT)
1094                         continue;
1095                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1096                         goto warn_put_all;
1097         }
1098
1099         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1100                 if (inode->i_dquot[cnt] == NODQUOT)
1101                         continue;
1102                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1103         }
1104         ret = QUOTA_OK;
1105 warn_put_all:
1106         spin_unlock(&dq_data_lock);
1107         if (ret == QUOTA_OK)
1108                 /* Dirtify all the dquots - this can block when journalling */
1109                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1110                         if (inode->i_dquot[cnt])
1111                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1112         flush_warnings((struct dquot **)inode->i_dquot, warntype);
1113         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1114         return ret;
1115 }
1116
1117 /*
1118  * This operation can block, but only after everything is updated
1119  */
1120 int dquot_free_space(struct inode *inode, qsize_t number)
1121 {
1122         unsigned int cnt;
1123
1124         /* First test before acquiring semaphore - solves deadlocks when we
1125          * re-enter the quota code and are already holding the semaphore */
1126         if (IS_NOQUOTA(inode)) {
1127 out_sub:
1128                 inode_sub_bytes(inode, number);
1129                 return QUOTA_OK;
1130         }
1131         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1132         /* Now recheck reliably when holding dqptr_sem */
1133         if (IS_NOQUOTA(inode)) {
1134                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1135                 goto out_sub;
1136         }
1137         spin_lock(&dq_data_lock);
1138         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1139                 if (inode->i_dquot[cnt] == NODQUOT)
1140                         continue;
1141                 dquot_decr_space(inode->i_dquot[cnt], number);
1142         }
1143         inode_sub_bytes(inode, number);
1144         spin_unlock(&dq_data_lock);
1145         /* Dirtify all the dquots - this can block when journalling */
1146         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1147                 if (inode->i_dquot[cnt])
1148                         mark_dquot_dirty(inode->i_dquot[cnt]);
1149         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1150         return QUOTA_OK;
1151 }
1152
1153 /*
1154  * This operation can block, but only after everything is updated
1155  */
1156 int dquot_free_inode(const struct inode *inode, unsigned long number)
1157 {
1158         unsigned int cnt;
1159
1160         /* First test before acquiring semaphore - solves deadlocks when we
1161          * re-enter the quota code and are already holding the semaphore */
1162         if (IS_NOQUOTA(inode))
1163                 return QUOTA_OK;
1164         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1165         /* Now recheck reliably when holding dqptr_sem */
1166         if (IS_NOQUOTA(inode)) {
1167                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1168                 return QUOTA_OK;
1169         }
1170         spin_lock(&dq_data_lock);
1171         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1172                 if (inode->i_dquot[cnt] == NODQUOT)
1173                         continue;
1174                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1175         }
1176         spin_unlock(&dq_data_lock);
1177         /* Dirtify all the dquots - this can block when journalling */
1178         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1179                 if (inode->i_dquot[cnt])
1180                         mark_dquot_dirty(inode->i_dquot[cnt]);
1181         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1182         return QUOTA_OK;
1183 }
1184
1185 /*
1186  * Transfer the number of inode and blocks from one diskquota to an other.
1187  *
1188  * This operation can block, but only after everything is updated
1189  * A transaction must be started when entering this function.
1190  */
1191 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1192 {
1193         qsize_t space;
1194         struct dquot *transfer_from[MAXQUOTAS];
1195         struct dquot *transfer_to[MAXQUOTAS];
1196         int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
1197             chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
1198         char warntype[MAXQUOTAS];
1199
1200         /* First test before acquiring semaphore - solves deadlocks when we
1201          * re-enter the quota code and are already holding the semaphore */
1202         if (IS_NOQUOTA(inode))
1203                 return QUOTA_OK;
1204         /* Clear the arrays */
1205         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1206                 transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
1207                 warntype[cnt] = NOWARN;
1208         }
1209         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1210         /* Now recheck reliably when holding dqptr_sem */
1211         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1212                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1213                 return QUOTA_OK;
1214         }
1215         /* First build the transfer_to list - here we can block on
1216          * reading/instantiating of dquots.  We know that the transaction for
1217          * us was already started so we don't violate lock ranking here */
1218         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1219                 switch (cnt) {
1220                         case USRQUOTA:
1221                                 if (!chuid)
1222                                         continue;
1223                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1224                                 break;
1225                         case GRPQUOTA:
1226                                 if (!chgid)
1227                                         continue;
1228                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1229                                 break;
1230                 }
1231         }
1232         spin_lock(&dq_data_lock);
1233         space = inode_get_bytes(inode);
1234         /* Build the transfer_from list and check the limits */
1235         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1236                 if (transfer_to[cnt] == NODQUOT)
1237                         continue;
1238                 transfer_from[cnt] = inode->i_dquot[cnt];
1239                 if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
1240                     check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
1241                         goto warn_put_all;
1242         }
1243
1244         /*
1245          * Finally perform the needed transfer from transfer_from to transfer_to
1246          */
1247         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1248                 /*
1249                  * Skip changes for same uid or gid or for turned off quota-type.
1250                  */
1251                 if (transfer_to[cnt] == NODQUOT)
1252                         continue;
1253
1254                 /* Due to IO error we might not have transfer_from[] structure */
1255                 if (transfer_from[cnt]) {
1256                         dquot_decr_inodes(transfer_from[cnt], 1);
1257                         dquot_decr_space(transfer_from[cnt], space);
1258                 }
1259
1260                 dquot_incr_inodes(transfer_to[cnt], 1);
1261                 dquot_incr_space(transfer_to[cnt], space);
1262
1263                 inode->i_dquot[cnt] = transfer_to[cnt];
1264         }
1265         ret = QUOTA_OK;
1266 warn_put_all:
1267         spin_unlock(&dq_data_lock);
1268         /* Dirtify all the dquots - this can block when journalling */
1269         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1270                 if (transfer_from[cnt])
1271                         mark_dquot_dirty(transfer_from[cnt]);
1272                 if (transfer_to[cnt])
1273                         mark_dquot_dirty(transfer_to[cnt]);
1274         }
1275         flush_warnings(transfer_to, warntype);
1276
1277         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1278                 if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
1279                         dqput(transfer_from[cnt]);
1280                 if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
1281                         dqput(transfer_to[cnt]);
1282         }
1283         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1284         return ret;
1285 }
1286
1287 /*
1288  * Write info of quota file to disk
1289  */
1290 int dquot_commit_info(struct super_block *sb, int type)
1291 {
1292         int ret;
1293         struct quota_info *dqopt = sb_dqopt(sb);
1294
1295         down(&dqopt->dqio_sem);
1296         ret = dqopt->ops[type]->write_file_info(sb, type);
1297         up(&dqopt->dqio_sem);
1298         return ret;
1299 }
1300
1301 /*
1302  * Definitions of diskquota operations.
1303  */
1304 struct dquot_operations dquot_operations = {
1305         .initialize     = dquot_initialize,
1306         .drop           = dquot_drop,
1307         .alloc_space    = dquot_alloc_space,
1308         .alloc_inode    = dquot_alloc_inode,
1309         .free_space     = dquot_free_space,
1310         .free_inode     = dquot_free_inode,
1311         .transfer       = dquot_transfer,
1312         .write_dquot    = dquot_commit,
1313         .acquire_dquot  = dquot_acquire,
1314         .release_dquot  = dquot_release,
1315         .mark_dirty     = dquot_mark_dquot_dirty,
1316         .write_info     = dquot_commit_info
1317 };
1318
1319 static inline void set_enable_flags(struct quota_info *dqopt, int type)
1320 {
1321         switch (type) {
1322                 case USRQUOTA:
1323                         dqopt->flags |= DQUOT_USR_ENABLED;
1324                         break;
1325                 case GRPQUOTA:
1326                         dqopt->flags |= DQUOT_GRP_ENABLED;
1327                         break;
1328         }
1329 }
1330
1331 static inline void reset_enable_flags(struct quota_info *dqopt, int type)
1332 {
1333         switch (type) {
1334                 case USRQUOTA:
1335                         dqopt->flags &= ~DQUOT_USR_ENABLED;
1336                         break;
1337                 case GRPQUOTA:
1338                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
1339                         break;
1340         }
1341 }
1342
1343 /*
1344  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1345  */
1346 int vfs_quota_off(struct super_block *sb, int type)
1347 {
1348         int cnt;
1349         struct quota_info *dqopt = sb_dqopt(sb);
1350         struct inode *toputinode[MAXQUOTAS];
1351
1352         /* We need to serialize quota_off() for device */
1353         down(&dqopt->dqonoff_sem);
1354         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1355                 toputinode[cnt] = NULL;
1356                 if (type != -1 && cnt != type)
1357                         continue;
1358                 if (!sb_has_quota_enabled(sb, cnt))
1359                         continue;
1360                 reset_enable_flags(dqopt, cnt);
1361
1362                 /* Note: these are blocking operations */
1363                 drop_dquot_ref(sb, cnt);
1364                 invalidate_dquots(sb, cnt);
1365                 /*
1366                  * Now all dquots should be invalidated, all writes done so we should be only
1367                  * users of the info. No locks needed.
1368                  */
1369                 if (info_dirty(&dqopt->info[cnt]))
1370                         sb->dq_op->write_info(sb, cnt);
1371                 if (dqopt->ops[cnt]->free_file_info)
1372                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1373                 put_quota_format(dqopt->info[cnt].dqi_format);
1374
1375                 toputinode[cnt] = dqopt->files[cnt];
1376                 dqopt->files[cnt] = NULL;
1377                 dqopt->info[cnt].dqi_flags = 0;
1378                 dqopt->info[cnt].dqi_igrace = 0;
1379                 dqopt->info[cnt].dqi_bgrace = 0;
1380                 dqopt->ops[cnt] = NULL;
1381         }
1382         up(&dqopt->dqonoff_sem);
1383         /* Sync the superblock so that buffers with quota data are written to
1384          * disk (and so userspace sees correct data afterwards). */
1385         if (sb->s_op->sync_fs)
1386                 sb->s_op->sync_fs(sb, 1);
1387         sync_blockdev(sb->s_bdev);
1388         /* Now the quota files are just ordinary files and we can set the
1389          * inode flags back. Moreover we discard the pagecache so that
1390          * userspace sees the writes we did bypassing the pagecache. We
1391          * must also discard the blockdev buffers so that we see the
1392          * changes done by userspace on the next quotaon() */
1393         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1394                 if (toputinode[cnt]) {
1395                         down(&dqopt->dqonoff_sem);
1396                         /* If quota was reenabled in the meantime, we have
1397                          * nothing to do */
1398                         if (!sb_has_quota_enabled(sb, cnt)) {
1399                                 mutex_lock(&toputinode[cnt]->i_mutex);
1400                                 toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
1401                                   S_NOATIME | S_NOQUOTA);
1402                                 truncate_inode_pages(&toputinode[cnt]->i_data, 0);
1403                                 mutex_unlock(&toputinode[cnt]->i_mutex);
1404                                 mark_inode_dirty(toputinode[cnt]);
1405                                 iput(toputinode[cnt]);
1406                         }
1407                         up(&dqopt->dqonoff_sem);
1408                 }
1409         if (sb->s_bdev)
1410                 invalidate_bdev(sb->s_bdev, 0);
1411         return 0;
1412 }
1413
1414 /*
1415  *      Turn quotas on on a device
1416  */
1417
1418 /* Helper function when we already have the inode */
1419 static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
1420 {
1421         struct quota_format_type *fmt = find_quota_format(format_id);
1422         struct super_block *sb = inode->i_sb;
1423         struct quota_info *dqopt = sb_dqopt(sb);
1424         int error;
1425         int oldflags = -1;
1426
1427         if (!fmt)
1428                 return -ESRCH;
1429         if (!S_ISREG(inode->i_mode)) {
1430                 error = -EACCES;
1431                 goto out_fmt;
1432         }
1433         if (IS_RDONLY(inode)) {
1434                 error = -EROFS;
1435                 goto out_fmt;
1436         }
1437         if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
1438                 error = -EINVAL;
1439                 goto out_fmt;
1440         }
1441
1442         /* As we bypass the pagecache we must now flush the inode so that
1443          * we see all the changes from userspace... */
1444         write_inode_now(inode, 1);
1445         /* And now flush the block cache so that kernel sees the changes */
1446         invalidate_bdev(sb->s_bdev, 0);
1447         mutex_lock(&inode->i_mutex);
1448         down(&dqopt->dqonoff_sem);
1449         if (sb_has_quota_enabled(sb, type)) {
1450                 error = -EBUSY;
1451                 goto out_lock;
1452         }
1453         /* We don't want quota and atime on quota files (deadlocks possible)
1454          * Also nobody should write to the file - we use special IO operations
1455          * which ignore the immutable bit. */
1456         down_write(&dqopt->dqptr_sem);
1457         oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
1458         inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
1459         up_write(&dqopt->dqptr_sem);
1460         sb->dq_op->drop(inode);
1461
1462         error = -EIO;
1463         dqopt->files[type] = igrab(inode);
1464         if (!dqopt->files[type])
1465                 goto out_lock;
1466         error = -EINVAL;
1467         if (!fmt->qf_ops->check_quota_file(sb, type))
1468                 goto out_file_init;
1469
1470         dqopt->ops[type] = fmt->qf_ops;
1471         dqopt->info[type].dqi_format = fmt;
1472         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1473         down(&dqopt->dqio_sem);
1474         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1475                 up(&dqopt->dqio_sem);
1476                 goto out_file_init;
1477         }
1478         up(&dqopt->dqio_sem);
1479         mutex_unlock(&inode->i_mutex);
1480         set_enable_flags(dqopt, type);
1481
1482         add_dquot_ref(sb, type);
1483         up(&dqopt->dqonoff_sem);
1484
1485         return 0;
1486
1487 out_file_init:
1488         dqopt->files[type] = NULL;
1489         iput(inode);
1490 out_lock:
1491         up(&dqopt->dqonoff_sem);
1492         if (oldflags != -1) {
1493                 down_write(&dqopt->dqptr_sem);
1494                 /* Set the flags back (in the case of accidental quotaon()
1495                  * on a wrong file we don't want to mess up the flags) */
1496                 inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
1497                 inode->i_flags |= oldflags;
1498                 up_write(&dqopt->dqptr_sem);
1499         }
1500         mutex_unlock(&inode->i_mutex);
1501 out_fmt:
1502         put_quota_format(fmt);
1503
1504         return error;
1505 }
1506
1507 /* Actual function called from quotactl() */
1508 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
1509 {
1510         struct nameidata nd;
1511         int error;
1512
1513         error = path_lookup(path, LOOKUP_FOLLOW, &nd);
1514         if (error < 0)
1515                 return error;
1516         error = security_quota_on(nd.dentry);
1517         if (error)
1518                 goto out_path;
1519         /* Quota file not on the same filesystem? */
1520         if (nd.mnt->mnt_sb != sb)
1521                 error = -EXDEV;
1522         else
1523                 error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
1524 out_path:
1525         path_release(&nd);
1526         return error;
1527 }
1528
1529 /*
1530  * This function is used when filesystem needs to initialize quotas
1531  * during mount time.
1532  */
1533 int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
1534                 int format_id, int type)
1535 {
1536         struct dentry *dentry;
1537         int error;
1538
1539         dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
1540         if (IS_ERR(dentry))
1541                 return PTR_ERR(dentry);
1542
1543         if (!dentry->d_inode) {
1544                 error = -ENOENT;
1545                 goto out;
1546         }
1547
1548         error = security_quota_on(dentry);
1549         if (!error)
1550                 error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
1551
1552 out:
1553         dput(dentry);
1554         return error;
1555 }
1556
1557 /* Generic routine for getting common part of quota structure */
1558 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
1559 {
1560         struct mem_dqblk *dm = &dquot->dq_dqb;
1561
1562         spin_lock(&dq_data_lock);
1563         di->dqb_bhardlimit = dm->dqb_bhardlimit;
1564         di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
1565         di->dqb_curspace = dm->dqb_curspace;
1566         di->dqb_ihardlimit = dm->dqb_ihardlimit;
1567         di->dqb_isoftlimit = dm->dqb_isoftlimit;
1568         di->dqb_curinodes = dm->dqb_curinodes;
1569         di->dqb_btime = dm->dqb_btime;
1570         di->dqb_itime = dm->dqb_itime;
1571         di->dqb_valid = QIF_ALL;
1572         spin_unlock(&dq_data_lock);
1573 }
1574
1575 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1576 {
1577         struct dquot *dquot;
1578
1579         down(&sb_dqopt(sb)->dqonoff_sem);
1580         if (!(dquot = dqget(sb, id, type))) {
1581                 up(&sb_dqopt(sb)->dqonoff_sem);
1582                 return -ESRCH;
1583         }
1584         do_get_dqblk(dquot, di);
1585         dqput(dquot);
1586         up(&sb_dqopt(sb)->dqonoff_sem);
1587         return 0;
1588 }
1589
1590 /* Generic routine for setting common part of quota structure */
1591 static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
1592 {
1593         struct mem_dqblk *dm = &dquot->dq_dqb;
1594         int check_blim = 0, check_ilim = 0;
1595
1596         spin_lock(&dq_data_lock);
1597         if (di->dqb_valid & QIF_SPACE) {
1598                 dm->dqb_curspace = di->dqb_curspace;
1599                 check_blim = 1;
1600         }
1601         if (di->dqb_valid & QIF_BLIMITS) {
1602                 dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
1603                 dm->dqb_bhardlimit = di->dqb_bhardlimit;
1604                 check_blim = 1;
1605         }
1606         if (di->dqb_valid & QIF_INODES) {
1607                 dm->dqb_curinodes = di->dqb_curinodes;
1608                 check_ilim = 1;
1609         }
1610         if (di->dqb_valid & QIF_ILIMITS) {
1611                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
1612                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
1613                 check_ilim = 1;
1614         }
1615         if (di->dqb_valid & QIF_BTIME)
1616                 dm->dqb_btime = di->dqb_btime;
1617         if (di->dqb_valid & QIF_ITIME)
1618                 dm->dqb_itime = di->dqb_itime;
1619
1620         if (check_blim) {
1621                 if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
1622                         dm->dqb_btime = 0;
1623                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1624                 }
1625                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
1626                         dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1627         }
1628         if (check_ilim) {
1629                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
1630                         dm->dqb_itime = 0;
1631                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1632                 }
1633                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
1634                         dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1635         }
1636         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
1637                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
1638         else
1639                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
1640         spin_unlock(&dq_data_lock);
1641         mark_dquot_dirty(dquot);
1642 }
1643
1644 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1645 {
1646         struct dquot *dquot;
1647
1648         down(&sb_dqopt(sb)->dqonoff_sem);
1649         if (!(dquot = dqget(sb, id, type))) {
1650                 up(&sb_dqopt(sb)->dqonoff_sem);
1651                 return -ESRCH;
1652         }
1653         do_set_dqblk(dquot, di);
1654         dqput(dquot);
1655         up(&sb_dqopt(sb)->dqonoff_sem);
1656         return 0;
1657 }
1658
1659 /* Generic routine for getting common part of quota file information */
1660 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1661 {
1662         struct mem_dqinfo *mi;
1663
1664         down(&sb_dqopt(sb)->dqonoff_sem);
1665         if (!sb_has_quota_enabled(sb, type)) {
1666                 up(&sb_dqopt(sb)->dqonoff_sem);
1667                 return -ESRCH;
1668         }
1669         mi = sb_dqopt(sb)->info + type;
1670         spin_lock(&dq_data_lock);
1671         ii->dqi_bgrace = mi->dqi_bgrace;
1672         ii->dqi_igrace = mi->dqi_igrace;
1673         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
1674         ii->dqi_valid = IIF_ALL;
1675         spin_unlock(&dq_data_lock);
1676         up(&sb_dqopt(sb)->dqonoff_sem);
1677         return 0;
1678 }
1679
1680 /* Generic routine for setting common part of quota file information */
1681 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1682 {
1683         struct mem_dqinfo *mi;
1684
1685         down(&sb_dqopt(sb)->dqonoff_sem);
1686         if (!sb_has_quota_enabled(sb, type)) {
1687                 up(&sb_dqopt(sb)->dqonoff_sem);
1688                 return -ESRCH;
1689         }
1690         mi = sb_dqopt(sb)->info + type;
1691         spin_lock(&dq_data_lock);
1692         if (ii->dqi_valid & IIF_BGRACE)
1693                 mi->dqi_bgrace = ii->dqi_bgrace;
1694         if (ii->dqi_valid & IIF_IGRACE)
1695                 mi->dqi_igrace = ii->dqi_igrace;
1696         if (ii->dqi_valid & IIF_FLAGS)
1697                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
1698         spin_unlock(&dq_data_lock);
1699         mark_info_dirty(sb, type);
1700         /* Force write to disk */
1701         sb->dq_op->write_info(sb, type);
1702         up(&sb_dqopt(sb)->dqonoff_sem);
1703         return 0;
1704 }
1705
1706 struct quotactl_ops vfs_quotactl_ops = {
1707         .quota_on       = vfs_quota_on,
1708         .quota_off      = vfs_quota_off,
1709         .quota_sync     = vfs_quota_sync,
1710         .get_info       = vfs_get_dqinfo,
1711         .set_info       = vfs_set_dqinfo,
1712         .get_dqblk      = vfs_get_dqblk,
1713         .set_dqblk      = vfs_set_dqblk
1714 };
1715
1716 static ctl_table fs_dqstats_table[] = {
1717         {
1718                 .ctl_name       = FS_DQ_LOOKUPS,
1719                 .procname       = "lookups",
1720                 .data           = &dqstats.lookups,
1721                 .maxlen         = sizeof(int),
1722                 .mode           = 0444,
1723                 .proc_handler   = &proc_dointvec,
1724         },
1725         {
1726                 .ctl_name       = FS_DQ_DROPS,
1727                 .procname       = "drops",
1728                 .data           = &dqstats.drops,
1729                 .maxlen         = sizeof(int),
1730                 .mode           = 0444,
1731                 .proc_handler   = &proc_dointvec,
1732         },
1733         {
1734                 .ctl_name       = FS_DQ_READS,
1735                 .procname       = "reads",
1736                 .data           = &dqstats.reads,
1737                 .maxlen         = sizeof(int),
1738                 .mode           = 0444,
1739                 .proc_handler   = &proc_dointvec,
1740         },
1741         {
1742                 .ctl_name       = FS_DQ_WRITES,
1743                 .procname       = "writes",
1744                 .data           = &dqstats.writes,
1745                 .maxlen         = sizeof(int),
1746                 .mode           = 0444,
1747                 .proc_handler   = &proc_dointvec,
1748         },
1749         {
1750                 .ctl_name       = FS_DQ_CACHE_HITS,
1751                 .procname       = "cache_hits",
1752                 .data           = &dqstats.cache_hits,
1753                 .maxlen         = sizeof(int),
1754                 .mode           = 0444,
1755                 .proc_handler   = &proc_dointvec,
1756         },
1757         {
1758                 .ctl_name       = FS_DQ_ALLOCATED,
1759                 .procname       = "allocated_dquots",
1760                 .data           = &dqstats.allocated_dquots,
1761                 .maxlen         = sizeof(int),
1762                 .mode           = 0444,
1763                 .proc_handler   = &proc_dointvec,
1764         },
1765         {
1766                 .ctl_name       = FS_DQ_FREE,
1767                 .procname       = "free_dquots",
1768                 .data           = &dqstats.free_dquots,
1769                 .maxlen         = sizeof(int),
1770                 .mode           = 0444,
1771                 .proc_handler   = &proc_dointvec,
1772         },
1773         {
1774                 .ctl_name       = FS_DQ_SYNCS,
1775                 .procname       = "syncs",
1776                 .data           = &dqstats.syncs,
1777                 .maxlen         = sizeof(int),
1778                 .mode           = 0444,
1779                 .proc_handler   = &proc_dointvec,
1780         },
1781         {
1782                 .ctl_name       = FS_DQ_WARNINGS,
1783                 .procname       = "warnings",
1784                 .data           = &flag_print_warnings,
1785                 .maxlen         = sizeof(int),
1786                 .mode           = 0644,
1787                 .proc_handler   = &proc_dointvec,
1788         },
1789         { .ctl_name = 0 },
1790 };
1791
1792 static ctl_table fs_table[] = {
1793         {
1794                 .ctl_name       = FS_DQSTATS,
1795                 .procname       = "quota",
1796                 .mode           = 0555,
1797                 .child          = fs_dqstats_table,
1798         },
1799         { .ctl_name = 0 },
1800 };
1801
1802 static ctl_table sys_table[] = {
1803         {
1804                 .ctl_name       = CTL_FS,
1805                 .procname       = "fs",
1806                 .mode           = 0555,
1807                 .child          = fs_table,
1808         },
1809         { .ctl_name = 0 },
1810 };
1811
1812 static int __init dquot_init(void)
1813 {
1814         int i;
1815         unsigned long nr_hash, order;
1816
1817         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
1818
1819         register_sysctl_table(sys_table, 0);
1820
1821         dquot_cachep = kmem_cache_create("dquot",
1822                         sizeof(struct dquot), sizeof(unsigned long) * 4,
1823                         SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
1824                         NULL, NULL);
1825
1826         order = 0;
1827         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
1828         if (!dquot_hash)
1829                 panic("Cannot create dquot hash table");
1830
1831         /* Find power-of-two hlist_heads which can fit into allocation */
1832         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
1833         dq_hash_bits = 0;
1834         do {
1835                 dq_hash_bits++;
1836         } while (nr_hash >> dq_hash_bits);
1837         dq_hash_bits--;
1838
1839         nr_hash = 1UL << dq_hash_bits;
1840         dq_hash_mask = nr_hash - 1;
1841         for (i = 0; i < nr_hash; i++)
1842                 INIT_HLIST_HEAD(dquot_hash + i);
1843
1844         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
1845                         nr_hash, order, (PAGE_SIZE << order));
1846
1847         set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
1848
1849         return 0;
1850 }
1851 module_init(dquot_init);
1852
1853 EXPORT_SYMBOL(register_quota_format);
1854 EXPORT_SYMBOL(unregister_quota_format);
1855 EXPORT_SYMBOL(dqstats);
1856 EXPORT_SYMBOL(dq_data_lock);
1857 EXPORT_SYMBOL(vfs_quota_on);
1858 EXPORT_SYMBOL(vfs_quota_on_mount);
1859 EXPORT_SYMBOL(vfs_quota_off);
1860 EXPORT_SYMBOL(vfs_quota_sync);
1861 EXPORT_SYMBOL(vfs_get_dqinfo);
1862 EXPORT_SYMBOL(vfs_set_dqinfo);
1863 EXPORT_SYMBOL(vfs_get_dqblk);
1864 EXPORT_SYMBOL(vfs_set_dqblk);
1865 EXPORT_SYMBOL(dquot_commit);
1866 EXPORT_SYMBOL(dquot_commit_info);
1867 EXPORT_SYMBOL(dquot_acquire);
1868 EXPORT_SYMBOL(dquot_release);
1869 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
1870 EXPORT_SYMBOL(dquot_initialize);
1871 EXPORT_SYMBOL(dquot_drop);
1872 EXPORT_SYMBOL(dquot_alloc_space);
1873 EXPORT_SYMBOL(dquot_alloc_inode);
1874 EXPORT_SYMBOL(dquot_free_space);
1875 EXPORT_SYMBOL(dquot_free_inode);
1876 EXPORT_SYMBOL(dquot_transfer);