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