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
  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/pagemap.h>
  79
  80 #include <asm/uaccess.h>
  81
  82 #define __DQUOT_PARANOIA
  83
  84 /*
  85  * There are two quota SMP locks. dq_list_lock protects all lists with quotas
  86  * and quota formats and also dqstats structure containing statistics about the
  87  * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
  88  * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
  89  * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
  90  * in inode_add_bytes() and inode_sub_bytes().
  91  *
  92  * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
  93  *
  94  * Note that some things (eg. sb pointer, type, id) doesn't change during
  95  * the life of the dquot structure and so needn't to be protected by a lock
  96  *
  97  * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
  98  * operation is just reading pointers from inode (or not using them at all) the
  99  * read lock is enough. If pointers are altered function must hold write lock.
 100  * If operation is holding reference to dquot in other way (e.g. quotactl ops)
 101  * it must be guarded by dqonoff_sem.
 102  * This locking assures that:
 103  *   a) update/access to dquot pointers in inode is serialized
 104  *   b) everyone is guarded against invalidate_dquots()
 105  *
 106  * Each dquot has its dq_lock semaphore. Locked dquots might not be referenced
 107  * from inodes (dquot_alloc_space() and such don't check the dq_lock).
 108  * Currently dquot is locked only when it is being read to memory (or space for
 109  * it is being allocated) on the first dqget() and when it is being released on
 110  * the last dqput(). The allocation and release oparations are serialized by
 111  * the dq_lock and by checking the use count in dquot_release().  Write
 112  * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
 113  * spinlock to internal buffers before writing.
 114  *
 115  * Lock ordering (including journal_lock) is following:
 116  *  dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock > dqio_sem
 117  */
 118
 119 spinlock_t dq_list_lock = SPIN_LOCK_UNLOCKED;
 120 spinlock_t dq_data_lock = SPIN_LOCK_UNLOCKED;
 121
 122 static char *quotatypes[] = INITQFNAMES;
 123 static struct quota_format_type *quota_formats; /* List of registered formats */
 124 static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
 125
 126 int register_quota_format(struct quota_format_type *fmt)
 127 {
 128         spin_lock(&dq_list_lock);
 129         fmt->qf_next = quota_formats;
 130         quota_formats = fmt;
 131         spin_unlock(&dq_list_lock);
 132         return 0;
 133 }
 134
 135 void unregister_quota_format(struct quota_format_type *fmt)
 136 {
 137         struct quota_format_type **actqf;
 138
 139         spin_lock(&dq_list_lock);
 140         for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
 141         if (*actqf)
 142                 *actqf = (*actqf)->qf_next;
 143         spin_unlock(&dq_list_lock);
 144 }
 145
 146 static struct quota_format_type *find_quota_format(int id)
 147 {
 148         struct quota_format_type *actqf;
 149
 150         spin_lock(&dq_list_lock);
 151         for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 152         if (!actqf || !try_module_get(actqf->qf_owner)) {
 153                 int qm;
 154
 155                 spin_unlock(&dq_list_lock);
 156
 157                 for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
 158                 if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
 159                         return NULL;
 160
 161                 spin_lock(&dq_list_lock);
 162                 for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
 163                 if (actqf && !try_module_get(actqf->qf_owner))
 164                         actqf = NULL;
 165         }
 166         spin_unlock(&dq_list_lock);
 167         return actqf;
 168 }
 169
 170 static void put_quota_format(struct quota_format_type *fmt)
 171 {
 172         module_put(fmt->qf_owner);
 173 }
 174
 175 /*
 176  * Dquot List Management:
 177  * The quota code uses three lists for dquot management: the inuse_list,
 178  * free_dquots, and dquot_hash[] array. A single dquot structure may be
 179  * on all three lists, depending on its current state.
 180  *
 181  * All dquots are placed to the end of inuse_list when first created, and this
 182  * list is used for the sync and invalidate operations, which must look
 183  * at every dquot.
 184  *
 185  * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 186  * and this list is searched whenever we need an available dquot.  Dquots are
 187  * removed from the list as soon as they are used again, and
 188  * dqstats.free_dquots gives the number of dquots on the list. When
 189  * dquot is invalidated it's completely released from memory.
 190  *
 191  * Dquots with a specific identity (device, type and id) are placed on
 192  * one of the dquot_hash[] hash chains. The provides an efficient search
 193  * mechanism to locate a specific dquot.
 194  */
 195
 196 static LIST_HEAD(inuse_list);
 197 static LIST_HEAD(free_dquots);
 198 unsigned int dq_hash_bits, dq_hash_mask;
 199 static struct hlist_head *dquot_hash;
 200
 201 struct dqstats dqstats;
 202
 203 static void dqput(struct dquot *dquot);
 204
 205 static inline int const hashfn(struct super_block *sb, unsigned int id, int type)
 206 {
 207         unsigned long tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
 208         return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
 209 }
 210
 211 /*
 212  * Following list functions expect dq_list_lock to be held
 213  */
 214 static inline void insert_dquot_hash(struct dquot *dquot)
 215 {
 216         struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
 217         hlist_add_head(&dquot->dq_hash, head);
 218 }
 219
 220 static inline void remove_dquot_hash(struct dquot *dquot)
 221 {
 222         hlist_del_init(&dquot->dq_hash);
 223 }
 224
 225 static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
 226 {
 227         struct hlist_node *node;
 228         struct dquot *dquot;
 229
 230         hlist_for_each (node, dquot_hash+hashent) {
 231                 dquot = hlist_entry(node, struct dquot, dq_hash);
 232                 if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
 233                         return dquot;
 234         }
 235         return NODQUOT;
 236 }
 237
 238 /* Add a dquot to the tail of the free list */
 239 static inline void put_dquot_last(struct dquot *dquot)
 240 {
 241         list_add(&dquot->dq_free, free_dquots.prev);
 242         dqstats.free_dquots++;
 243 }
 244
 245 static inline void remove_free_dquot(struct dquot *dquot)
 246 {
 247         if (list_empty(&dquot->dq_free))
 248                 return;
 249         list_del_init(&dquot->dq_free);
 250         dqstats.free_dquots--;
 251 }
 252
 253 static inline void put_inuse(struct dquot *dquot)
 254 {
 255         /* We add to the back of inuse list so we don't have to restart
 256          * when traversing this list and we block */
 257         list_add(&dquot->dq_inuse, inuse_list.prev);
 258         dqstats.allocated_dquots++;
 259 }
 260
 261 static inline void remove_inuse(struct dquot *dquot)
 262 {
 263         dqstats.allocated_dquots--;
 264         list_del(&dquot->dq_inuse);
 265 }
 266 /*
 267  * End of list functions needing dq_list_lock
 268  */
 269
 270 static void wait_on_dquot(struct dquot *dquot)
 271 {
 272         down(&dquot->dq_lock);
 273         up(&dquot->dq_lock);
 274 }
 275
 276 #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
 277
 278 int dquot_mark_dquot_dirty(struct dquot *dquot)
 279 {
 280         spin_lock(&dq_list_lock);
 281         if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
 282                 list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
 283                                 info[dquot->dq_type].dqi_dirty_list);
 284         spin_unlock(&dq_list_lock);
 285         return 0;
 286 }
 287
 288 /* This function needs dq_list_lock */
 289 static inline int clear_dquot_dirty(struct dquot *dquot)
 290 {
 291         if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
 292                 return 0;
 293         list_del_init(&dquot->dq_dirty);
 294         return 1;
 295 }
 296
 297 void mark_info_dirty(struct super_block *sb, int type)
 298 {
 299         set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
 300 }
 301 EXPORT_SYMBOL(mark_info_dirty);
 302
 303 /*
 304  *      Read dquot from disk and alloc space for it
 305  */
 306
 307 int dquot_acquire(struct dquot *dquot)
 308 {
 309         int ret = 0, ret2 = 0;
 310         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 311
 312         down(&dquot->dq_lock);
 313         down(&dqopt->dqio_sem);
 314         if (!test_bit(DQ_READ_B, &dquot->dq_flags))
 315                 ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
 316         if (ret < 0)
 317                 goto out_iolock;
 318         set_bit(DQ_READ_B, &dquot->dq_flags);
 319         /* Instantiate dquot if needed */
 320         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
 321                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 322                 /* Write the info if needed */
 323                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 324                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 325                 if (ret < 0)
 326                         goto out_iolock;
 327                 if (ret2 < 0) {
 328                         ret = ret2;
 329                         goto out_iolock;
 330                 }
 331         }
 332         set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 333 out_iolock:
 334         up(&dqopt->dqio_sem);
 335         up(&dquot->dq_lock);
 336         return ret;
 337 }
 338
 339 /*
 340  *      Write dquot to disk
 341  */
 342 int dquot_commit(struct dquot *dquot)
 343 {
 344         int ret = 0, ret2 = 0;
 345         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 346
 347         down(&dqopt->dqio_sem);
 348         spin_lock(&dq_list_lock);
 349         if (!clear_dquot_dirty(dquot)) {
 350                 spin_unlock(&dq_list_lock);
 351                 goto out_sem;
 352         }
 353         spin_unlock(&dq_list_lock);
 354         /* Inactive dquot can be only if there was error during read/init
 355          * => we have better not writing it */
 356         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 357                 ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
 358                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 359                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 360                 if (ret >= 0)
 361                         ret = ret2;
 362         }
 363 out_sem:
 364         up(&dqopt->dqio_sem);
 365         return ret;
 366 }
 367
 368 /*
 369  *      Release dquot
 370  */
 371 int dquot_release(struct dquot *dquot)
 372 {
 373         int ret = 0, ret2 = 0;
 374         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 375
 376         down(&dquot->dq_lock);
 377         /* Check whether we are not racing with some other dqget() */
 378         if (atomic_read(&dquot->dq_count) > 1)
 379                 goto out_dqlock;
 380         down(&dqopt->dqio_sem);
 381         if (dqopt->ops[dquot->dq_type]->release_dqblk) {
 382                 ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
 383                 /* Write the info */
 384                 if (info_dirty(&dqopt->info[dquot->dq_type]))
 385                         ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
 386                 if (ret >= 0)
 387                         ret = ret2;
 388         }
 389         clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
 390         up(&dqopt->dqio_sem);
 391 out_dqlock:
 392         up(&dquot->dq_lock);
 393         return ret;
 394 }
 395
 396 /* Invalidate all dquots on the list. Note that this function is called after
 397  * quota is disabled and pointers from inodes removed so there cannot be new
 398  * quota users. Also because we hold dqonoff_sem there can be no quota users
 399  * for this sb+type at all. */
 400 static void invalidate_dquots(struct super_block *sb, int type)
 401 {
 402         struct dquot *dquot;
 403         struct list_head *head;
 404
 405         spin_lock(&dq_list_lock);
 406         for (head = inuse_list.next; head != &inuse_list;) {
 407                 dquot = list_entry(head, struct dquot, dq_inuse);
 408                 head = head->next;
 409                 if (dquot->dq_sb != sb)
 410                         continue;
 411                 if (dquot->dq_type != type)
 412                         continue;
 413 #ifdef __DQUOT_PARANOIA
 414                 if (atomic_read(&dquot->dq_count))
 415                         BUG();
 416 #endif
 417                 /* Quota now has no users and it has been written on last dqput() */
 418                 remove_dquot_hash(dquot);
 419                 remove_free_dquot(dquot);
 420                 remove_inuse(dquot);
 421                 kmem_cache_free(dquot_cachep, dquot);
 422         }
 423         spin_unlock(&dq_list_lock);
 424 }
 425
 426 int vfs_quota_sync(struct super_block *sb, int type)
 427 {
 428         struct list_head *dirty;
 429         struct dquot *dquot;
 430         struct quota_info *dqopt = sb_dqopt(sb);
 431         int cnt;
 432
 433         down(&dqopt->dqonoff_sem);
 434         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 435                 if (type != -1 && cnt != type)
 436                         continue;
 437                 if (!sb_has_quota_enabled(sb, cnt))
 438                         continue;
 439                 spin_lock(&dq_list_lock);
 440                 dirty = &dqopt->info[cnt].dqi_dirty_list;
 441                 while (!list_empty(dirty)) {
 442                         dquot = list_entry(dirty->next, struct dquot, dq_dirty);
 443                         /* Dirty and inactive can be only bad dquot... */
 444                         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 445                                 clear_dquot_dirty(dquot);
 446                                 continue;
 447                         }
 448                         /* Now we have active dquot from which someone is
 449                          * holding reference so we can safely just increase
 450                          * use count */
 451                         atomic_inc(&dquot->dq_count);
 452                         dqstats.lookups++;
 453                         spin_unlock(&dq_list_lock);
 454                         sb->dq_op->write_dquot(dquot);
 455                         dqput(dquot);
 456                         spin_lock(&dq_list_lock);
 457                 }
 458                 spin_unlock(&dq_list_lock);
 459         }
 460
 461         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 462                 if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
 463                         && info_dirty(&dqopt->info[cnt]))
 464                         sb->dq_op->write_info(sb, cnt);
 465         spin_lock(&dq_list_lock);
 466         dqstats.syncs++;
 467         spin_unlock(&dq_list_lock);
 468         up(&dqopt->dqonoff_sem);
 469
 470         return 0;
 471 }
 472
 473 /* Free unused dquots from cache */
 474 static void prune_dqcache(int count)
 475 {
 476         struct list_head *head;
 477         struct dquot *dquot;
 478
 479         head = free_dquots.prev;
 480         while (head != &free_dquots && count) {
 481                 dquot = list_entry(head, struct dquot, dq_free);
 482                 remove_dquot_hash(dquot);
 483                 remove_free_dquot(dquot);
 484                 remove_inuse(dquot);
 485                 kmem_cache_free(dquot_cachep, dquot);
 486                 count--;
 487                 head = free_dquots.prev;
 488         }
 489 }
 490
 491 /*
 492  * This is called from kswapd when we think we need some
 493  * more memory
 494  */
 495
 496 static int shrink_dqcache_memory(int nr, unsigned int gfp_mask)
 497 {
 498         int ret;
 499
 500         spin_lock(&dq_list_lock);
 501         if (nr)
 502                 prune_dqcache(nr);
 503         ret = dqstats.allocated_dquots;
 504         spin_unlock(&dq_list_lock);
 505         return ret;
 506 }
 507
 508 /*
 509  * Put reference to dquot
 510  * NOTE: If you change this function please check whether dqput_blocks() works right...
 511  * MUST be called with either dqptr_sem or dqonoff_sem held
 512  */
 513 static void dqput(struct dquot *dquot)
 514 {
 515         if (!dquot)
 516                 return;
 517 #ifdef __DQUOT_PARANOIA
 518         if (!atomic_read(&dquot->dq_count)) {
 519                 printk("VFS: dqput: trying to free free dquot\n");
 520                 printk("VFS: device %s, dquot of %s %d\n",
 521                         dquot->dq_sb->s_id,
 522                         quotatypes[dquot->dq_type],
 523                         dquot->dq_id);
 524                 BUG();
 525         }
 526 #endif
 527
 528         spin_lock(&dq_list_lock);
 529         dqstats.drops++;
 530         spin_unlock(&dq_list_lock);
 531 we_slept:
 532         spin_lock(&dq_list_lock);
 533         if (atomic_read(&dquot->dq_count) > 1) {
 534                 /* We have more than one user... nothing to do */
 535                 atomic_dec(&dquot->dq_count);
 536                 spin_unlock(&dq_list_lock);
 537                 return;
 538         }
 539         /* Need to release dquot? */
 540         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
 541                 spin_unlock(&dq_list_lock);
 542                 /* Commit dquot before releasing */
 543                 dquot->dq_sb->dq_op->write_dquot(dquot);
 544                 goto we_slept;
 545         }
 546         /* Clear flag in case dquot was inactive (something bad happened) */
 547         clear_dquot_dirty(dquot);
 548         if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
 549                 spin_unlock(&dq_list_lock);
 550                 dquot->dq_sb->dq_op->release_dquot(dquot);
 551                 goto we_slept;
 552         }
 553         atomic_dec(&dquot->dq_count);
 554 #ifdef __DQUOT_PARANOIA
 555         /* sanity check */
 556         if (!list_empty(&dquot->dq_free))
 557                 BUG();
 558 #endif
 559         put_dquot_last(dquot);
 560         spin_unlock(&dq_list_lock);
 561 }
 562
 563 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 564 {
 565         struct dquot *dquot;
 566
 567         dquot = kmem_cache_alloc(dquot_cachep, SLAB_NOFS);
 568         if(!dquot)
 569                 return NODQUOT;
 570
 571         memset((caddr_t)dquot, 0, sizeof(struct dquot));
 572         sema_init(&dquot->dq_lock, 1);
 573         INIT_LIST_HEAD(&dquot->dq_free);
 574         INIT_LIST_HEAD(&dquot->dq_inuse);
 575         INIT_HLIST_NODE(&dquot->dq_hash);
 576         INIT_LIST_HEAD(&dquot->dq_dirty);
 577         dquot->dq_sb = sb;
 578         dquot->dq_type = type;
 579         atomic_set(&dquot->dq_count, 1);
 580
 581         return dquot;
 582 }
 583
 584 /*
 585  * Get reference to dquot
 586  * MUST be called with either dqptr_sem or dqonoff_sem held
 587  */
 588 static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
 589 {
 590         unsigned int hashent = hashfn(sb, id, type);
 591         struct dquot *dquot, *empty = NODQUOT;
 592
 593         if (!sb_has_quota_enabled(sb, type))
 594                 return NODQUOT;
 595 we_slept:
 596         spin_lock(&dq_list_lock);
 597         if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
 598                 if (empty == NODQUOT) {
 599                         spin_unlock(&dq_list_lock);
 600                         if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
 601                                 schedule();     /* Try to wait for a moment... */
 602                         goto we_slept;
 603                 }
 604                 dquot = empty;
 605                 dquot->dq_id = id;
 606                 /* all dquots go on the inuse_list */
 607                 put_inuse(dquot);
 608                 /* hash it first so it can be found */
 609                 insert_dquot_hash(dquot);
 610                 dqstats.lookups++;
 611                 spin_unlock(&dq_list_lock);
 612         } else {
 613                 if (!atomic_read(&dquot->dq_count))
 614                         remove_free_dquot(dquot);
 615                 atomic_inc(&dquot->dq_count);
 616                 dqstats.cache_hits++;
 617                 dqstats.lookups++;
 618                 spin_unlock(&dq_list_lock);
 619                 if (empty)
 620                         kmem_cache_free(dquot_cachep, empty);
 621         }
 622         /* Wait for dq_lock - after this we know that either dquot_release() is already
 623          * finished or it will be canceled due to dq_count > 1 test */
 624         wait_on_dquot(dquot);
 625         /* Read the dquot and instantiate it (everything done only if needed) */
 626         if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
 627                 dqput(dquot);
 628                 return NODQUOT;
 629         }
 630 #ifdef __DQUOT_PARANOIA
 631         if (!dquot->dq_sb)      /* Has somebody invalidated entry under us? */
 632                 BUG();
 633 #endif
 634
 635         return dquot;
 636 }
 637
 638 static int dqinit_needed(struct inode *inode, int type)
 639 {
 640         int cnt;
 641
 642         if (IS_NOQUOTA(inode))
 643                 return 0;
 644         if (type != -1)
 645                 return inode->i_dquot[type] == NODQUOT;
 646         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
 647                 if (inode->i_dquot[cnt] == NODQUOT)
 648                         return 1;
 649         return 0;
 650 }
 651
 652 /* This routine is guarded by dqonoff_sem semaphore */
 653 static void add_dquot_ref(struct super_block *sb, int type)
 654 {
 655         struct list_head *p;
 656
 657 restart:
 658         file_list_lock();
 659         list_for_each(p, &sb->s_files) {
 660                 struct file *filp = list_entry(p, struct file, f_list);
 661                 struct inode *inode = filp->f_dentry->d_inode;
 662                 if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
 663                         struct dentry *dentry = dget(filp->f_dentry);
 664                         file_list_unlock();
 665                         sb->dq_op->initialize(inode, type);
 666                         dput(dentry);
 667                         /* As we may have blocked we had better restart... */
 668                         goto restart;
 669                 }
 670         }
 671         file_list_unlock();
 672 }
 673
 674 /* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
 675 static inline int dqput_blocks(struct dquot *dquot)
 676 {
 677         if (atomic_read(&dquot->dq_count) <= 1)
 678                 return 1;
 679         return 0;
 680 }
 681
 682 /* Remove references to dquots from inode - add dquot to list for freeing if needed */
 683 /* We can't race with anybody because we hold dqptr_sem for writing... */
 684 int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
 685 {
 686         struct dquot *dquot = inode->i_dquot[type];
 687         int cnt;
 688
 689         inode->i_dquot[type] = NODQUOT;
 690         /* any other quota in use? */
 691         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 692                 if (inode->i_dquot[cnt] != NODQUOT)
 693                         goto put_it;
 694         }
 695         inode->i_flags &= ~S_QUOTA;
 696 put_it:
 697         if (dquot != NODQUOT) {
 698                 if (dqput_blocks(dquot)) {
 699 #ifdef __DQUOT_PARANOIA
 700                         if (atomic_read(&dquot->dq_count) != 1)
 701                                 printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
 702 #endif
 703                         spin_lock(&dq_list_lock);
 704                         list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
 705                         spin_unlock(&dq_list_lock);
 706                         return 1;
 707                 }
 708                 else
 709                         dqput(dquot);   /* We have guaranteed we won't block */
 710         }
 711         return 0;
 712 }
 713
 714 /* Free list of dquots - called from inode.c */
 715 /* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
 716 static void put_dquot_list(struct list_head *tofree_head)
 717 {
 718         struct list_head *act_head;
 719         struct dquot *dquot;
 720
 721         act_head = tofree_head->next;
 722         /* So now we have dquots on the list... Just free them */
 723         while (act_head != tofree_head) {
 724                 dquot = list_entry(act_head, struct dquot, dq_free);
 725                 act_head = act_head->next;
 726                 list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
 727                 dqput(dquot);
 728         }
 729 }
 730
 731 /* Function in inode.c - remove pointers to dquots in icache */
 732 extern void remove_dquot_ref(struct super_block *, int, struct list_head *);
 733
 734 /* Gather all references from inodes and drop them */
 735 static void drop_dquot_ref(struct super_block *sb, int type)
 736 {
 737         LIST_HEAD(tofree_head);
 738
 739         down_write(&sb_dqopt(sb)->dqptr_sem);
 740         remove_dquot_ref(sb, type, &tofree_head);
 741         up_write(&sb_dqopt(sb)->dqptr_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 inline int need_print_warning(struct dquot *dquot)
 778 {
 779         switch (dquot->dq_type) {
 780                 case USRQUOTA:
 781                         return current->fsuid == dquot->dq_id;
 782                 case GRPQUOTA:
 783                         return in_group_p(dquot->dq_id);
 784         }
 785         return 0;
 786 }
 787
 788 /* Values of warnings */
 789 #define NOWARN 0
 790 #define IHARDWARN 1
 791 #define ISOFTLONGWARN 2
 792 #define ISOFTWARN 3
 793 #define BHARDWARN 4
 794 #define BSOFTLONGWARN 5
 795 #define BSOFTWARN 6
 796
 797 /* Print warning to user which exceeded quota */
 798 static void print_warning(struct dquot *dquot, const char warntype)
 799 {
 800         char *msg = NULL;
 801         int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
 802           ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
 803
 804         if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
 805                 return;
 806         tty_write_message(current->signal->tty, dquot->dq_sb->s_id);
 807         if (warntype == ISOFTWARN || warntype == BSOFTWARN)
 808                 tty_write_message(current->signal->tty, ": warning, ");
 809         else
 810                 tty_write_message(current->signal->tty, ": write failed, ");
 811         tty_write_message(current->signal->tty, quotatypes[dquot->dq_type]);
 812         switch (warntype) {
 813                 case IHARDWARN:
 814                         msg = " file limit reached.\n";
 815                         break;
 816                 case ISOFTLONGWARN:
 817                         msg = " file quota exceeded too long.\n";
 818                         break;
 819                 case ISOFTWARN:
 820                         msg = " file quota exceeded.\n";
 821                         break;
 822                 case BHARDWARN:
 823                         msg = " block limit reached.\n";
 824                         break;
 825                 case BSOFTLONGWARN:
 826                         msg = " block quota exceeded too long.\n";
 827                         break;
 828                 case BSOFTWARN:
 829                         msg = " block quota exceeded.\n";
 830                         break;
 831         }
 832         tty_write_message(current->signal->tty, msg);
 833 }
 834
 835 static inline void flush_warnings(struct dquot **dquots, char *warntype)
 836 {
 837         int i;
 838
 839         for (i = 0; i < MAXQUOTAS; i++)
 840                 if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
 841                         print_warning(dquots[i], warntype[i]);
 842 }
 843
 844 static inline char ignore_hardlimit(struct dquot *dquot)
 845 {
 846         struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
 847
 848         return capable(CAP_SYS_RESOURCE) &&
 849             (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
 850 }
 851
 852 /* needs dq_data_lock */
 853 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
 854 {
 855         *warntype = NOWARN;
 856         if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
 857                 return QUOTA_OK;
 858
 859         if (dquot->dq_dqb.dqb_ihardlimit &&
 860            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
 861             !ignore_hardlimit(dquot)) {
 862                 *warntype = IHARDWARN;
 863                 return NO_QUOTA;
 864         }
 865
 866         if (dquot->dq_dqb.dqb_isoftlimit &&
 867            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
 868             dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
 869             !ignore_hardlimit(dquot)) {
 870                 *warntype = ISOFTLONGWARN;
 871                 return NO_QUOTA;
 872         }
 873
 874         if (dquot->dq_dqb.dqb_isoftlimit &&
 875            (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
 876             dquot->dq_dqb.dqb_itime == 0) {
 877                 *warntype = ISOFTWARN;
 878                 dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
 879         }
 880
 881         return QUOTA_OK;
 882 }
 883
 884 /* needs dq_data_lock */
 885 static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
 886 {
 887         *warntype = 0;
 888         if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
 889                 return QUOTA_OK;
 890
 891         if (dquot->dq_dqb.dqb_bhardlimit &&
 892            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
 893             !ignore_hardlimit(dquot)) {
 894                 if (!prealloc)
 895                         *warntype = BHARDWARN;
 896                 return NO_QUOTA;
 897         }
 898
 899         if (dquot->dq_dqb.dqb_bsoftlimit &&
 900            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
 901             dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
 902             !ignore_hardlimit(dquot)) {
 903                 if (!prealloc)
 904                         *warntype = BSOFTLONGWARN;
 905                 return NO_QUOTA;
 906         }
 907
 908         if (dquot->dq_dqb.dqb_bsoftlimit &&
 909            toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
 910             dquot->dq_dqb.dqb_btime == 0) {
 911                 if (!prealloc) {
 912                         *warntype = BSOFTWARN;
 913                         dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
 914                 }
 915                 else
 916                         /*
 917                          * We don't allow preallocation to exceed softlimit so exceeding will
 918                          * be always printed
 919                          */
 920                         return NO_QUOTA;
 921         }
 922
 923         return QUOTA_OK;
 924 }
 925
 926 /*
 927  *      Initialize quota pointers in inode
 928  *      Transaction must be started at entry
 929  */
 930 int dquot_initialize(struct inode *inode, int type)
 931 {
 932         unsigned int id = 0;
 933         int cnt, ret = 0;
 934
 935         /* First test before acquiring semaphore - solves deadlocks when we
 936          * re-enter the quota code and are already holding the semaphore */
 937         if (IS_NOQUOTA(inode))
 938                 return 0;
 939         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 940         /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
 941         if (IS_NOQUOTA(inode))
 942                 goto out_err;
 943         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 944                 if (type != -1 && cnt != type)
 945                         continue;
 946                 if (inode->i_dquot[cnt] == NODQUOT) {
 947                         switch (cnt) {
 948                                 case USRQUOTA:
 949                                         id = inode->i_uid;
 950                                         break;
 951                                 case GRPQUOTA:
 952                                         id = inode->i_gid;
 953                                         break;
 954                         }
 955                         inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
 956                         if (inode->i_dquot[cnt])
 957                                 inode->i_flags |= S_QUOTA;
 958                 }
 959         }
 960 out_err:
 961         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 962         return ret;
 963 }
 964
 965 /*
 966  *      Release all quotas referenced by inode
 967  *      Transaction must be started at an entry
 968  */
 969 int dquot_drop(struct inode *inode)
 970 {
 971         int cnt;
 972
 973         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 974         inode->i_flags &= ~S_QUOTA;
 975         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 976                 if (inode->i_dquot[cnt] != NODQUOT) {
 977                         dqput(inode->i_dquot[cnt]);
 978                         inode->i_dquot[cnt] = NODQUOT;
 979                 }
 980         }
 981         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
 982         return 0;
 983 }
 984
 985 /*
 986  * Following four functions update i_blocks+i_bytes fields and
 987  * quota information (together with appropriate checks)
 988  * NOTE: We absolutely rely on the fact that caller dirties
 989  * the inode (usually macros in quotaops.h care about this) and
 990  * holds a handle for the current transaction so that dquot write and
 991  * inode write go into the same transaction.
 992  */
 993
 994 /*
 995  * This operation can block, but only after everything is updated
 996  */
 997 int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
 998 {
 999         int cnt, ret = NO_QUOTA;
1000         char warntype[MAXQUOTAS];
1001
1002         /* First test before acquiring semaphore - solves deadlocks when we
1003          * re-enter the quota code and are already holding the semaphore */
1004         if (IS_NOQUOTA(inode)) {
1005 out_add:
1006                 inode_add_bytes(inode, number);
1007                 return QUOTA_OK;
1008         }
1009         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1010                 warntype[cnt] = NOWARN;
1011
1012         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1013         if (IS_NOQUOTA(inode)) {        /* Now we can do reliable test... */
1014                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1015                 goto out_add;
1016         }
1017         spin_lock(&dq_data_lock);
1018         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1019                 if (inode->i_dquot[cnt] == NODQUOT)
1020                         continue;
1021                 if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
1022                         goto warn_put_all;
1023         }
1024         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1025                 if (inode->i_dquot[cnt] == NODQUOT)
1026                         continue;
1027                 dquot_incr_space(inode->i_dquot[cnt], number);
1028         }
1029         inode_add_bytes(inode, number);
1030         ret = QUOTA_OK;
1031 warn_put_all:
1032         spin_unlock(&dq_data_lock);
1033         if (ret == QUOTA_OK)
1034                 /* Dirtify all the dquots - this can block when journalling */
1035                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1036                         if (inode->i_dquot[cnt])
1037                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1038         flush_warnings(inode->i_dquot, warntype);
1039         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1040         return ret;
1041 }
1042
1043 /*
1044  * This operation can block, but only after everything is updated
1045  */
1046 int dquot_alloc_inode(const struct inode *inode, unsigned long number)
1047 {
1048         int cnt, ret = NO_QUOTA;
1049         char warntype[MAXQUOTAS];
1050
1051         /* First test before acquiring semaphore - solves deadlocks when we
1052          * re-enter the quota code and are already holding the semaphore */
1053         if (IS_NOQUOTA(inode))
1054                 return QUOTA_OK;
1055         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1056                 warntype[cnt] = NOWARN;
1057         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1058         if (IS_NOQUOTA(inode)) {
1059                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1060                 return QUOTA_OK;
1061         }
1062         spin_lock(&dq_data_lock);
1063         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1064                 if (inode->i_dquot[cnt] == NODQUOT)
1065                         continue;
1066                 if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
1067                         goto warn_put_all;
1068         }
1069
1070         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1071                 if (inode->i_dquot[cnt] == NODQUOT)
1072                         continue;
1073                 dquot_incr_inodes(inode->i_dquot[cnt], number);
1074         }
1075         ret = QUOTA_OK;
1076 warn_put_all:
1077         spin_unlock(&dq_data_lock);
1078         if (ret == QUOTA_OK)
1079                 /* Dirtify all the dquots - this can block when journalling */
1080                 for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1081                         if (inode->i_dquot[cnt])
1082                                 mark_dquot_dirty(inode->i_dquot[cnt]);
1083         flush_warnings((struct dquot **)inode->i_dquot, warntype);
1084         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1085         return ret;
1086 }
1087
1088 /*
1089  * This is a non-blocking operation.
1090  */
1091 int dquot_free_space(struct inode *inode, qsize_t number)
1092 {
1093         unsigned int cnt;
1094
1095         /* First test before acquiring semaphore - solves deadlocks when we
1096          * re-enter the quota code and are already holding the semaphore */
1097         if (IS_NOQUOTA(inode)) {
1098 out_sub:
1099                 inode_sub_bytes(inode, number);
1100                 return QUOTA_OK;
1101         }
1102         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1103         /* Now recheck reliably when holding dqptr_sem */
1104         if (IS_NOQUOTA(inode)) {
1105                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1106                 goto out_sub;
1107         }
1108         spin_lock(&dq_data_lock);
1109         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1110                 if (inode->i_dquot[cnt] == NODQUOT)
1111                         continue;
1112                 dquot_decr_space(inode->i_dquot[cnt], number);
1113         }
1114         inode_sub_bytes(inode, number);
1115         spin_unlock(&dq_data_lock);
1116         /* Dirtify all the dquots - this can block when journalling */
1117         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1118                 if (inode->i_dquot[cnt])
1119                         mark_dquot_dirty(inode->i_dquot[cnt]);
1120         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1121         return QUOTA_OK;
1122 }
1123
1124 /*
1125  * This is a non-blocking operation.
1126  */
1127 int dquot_free_inode(const struct inode *inode, unsigned long number)
1128 {
1129         unsigned int cnt;
1130
1131         /* First test before acquiring semaphore - solves deadlocks when we
1132          * re-enter the quota code and are already holding the semaphore */
1133         if (IS_NOQUOTA(inode))
1134                 return QUOTA_OK;
1135         down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1136         /* Now recheck reliably when holding dqptr_sem */
1137         if (IS_NOQUOTA(inode)) {
1138                 up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1139                 return QUOTA_OK;
1140         }
1141         spin_lock(&dq_data_lock);
1142         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1143                 if (inode->i_dquot[cnt] == NODQUOT)
1144                         continue;
1145                 dquot_decr_inodes(inode->i_dquot[cnt], number);
1146         }
1147         spin_unlock(&dq_data_lock);
1148         /* Dirtify all the dquots - this can block when journalling */
1149         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
1150                 if (inode->i_dquot[cnt])
1151                         mark_dquot_dirty(inode->i_dquot[cnt]);
1152         up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
1153         return QUOTA_OK;
1154 }
1155
1156 /*
1157  * Transfer the number of inode and blocks from one diskquota to an other.
1158  *
1159  * This operation can block, but only after everything is updated
1160  */
1161 int dquot_transfer(struct inode *inode, struct iattr *iattr)
1162 {
1163         qsize_t space;
1164         struct dquot *transfer_from[MAXQUOTAS];
1165         struct dquot *transfer_to[MAXQUOTAS];
1166         int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
1167             chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
1168         char warntype[MAXQUOTAS];
1169
1170         /* First test before acquiring semaphore - solves deadlocks when we
1171          * re-enter the quota code and are already holding the semaphore */
1172         if (IS_NOQUOTA(inode))
1173                 return QUOTA_OK;
1174         /* Clear the arrays */
1175         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1176                 transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
1177                 warntype[cnt] = NOWARN;
1178         }
1179         down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1180         /* Now recheck reliably when holding dqptr_sem */
1181         if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
1182                 up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1183                 return QUOTA_OK;
1184         }
1185         /* First build the transfer_to list - here we can block on
1186          * reading/instantiating of dquots.  We know that the transaction for
1187          * us was already started so we don't violate lock ranking here */
1188         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1189                 switch (cnt) {
1190                         case USRQUOTA:
1191                                 if (!chuid)
1192                                         continue;
1193                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
1194                                 break;
1195                         case GRPQUOTA:
1196                                 if (!chgid)
1197                                         continue;
1198                                 transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
1199                                 break;
1200                 }
1201         }
1202         spin_lock(&dq_data_lock);
1203         space = inode_get_bytes(inode);
1204         /* Build the transfer_from list and check the limits */
1205         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1206                 if (transfer_to[cnt] == NODQUOT)
1207                         continue;
1208                 transfer_from[cnt] = inode->i_dquot[cnt];
1209                 if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
1210                     check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
1211                         goto warn_put_all;
1212         }
1213
1214         /*
1215          * Finally perform the needed transfer from transfer_from to transfer_to
1216          */
1217         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1218                 /*
1219                  * Skip changes for same uid or gid or for turned off quota-type.
1220                  */
1221                 if (transfer_to[cnt] == NODQUOT)
1222                         continue;
1223
1224                 /* Due to IO error we might not have transfer_from[] structure */
1225                 if (transfer_from[cnt]) {
1226                         dquot_decr_inodes(transfer_from[cnt], 1);
1227                         dquot_decr_space(transfer_from[cnt], space);
1228                 }
1229
1230                 dquot_incr_inodes(transfer_to[cnt], 1);
1231                 dquot_incr_space(transfer_to[cnt], space);
1232
1233                 inode->i_dquot[cnt] = transfer_to[cnt];
1234         }
1235         ret = QUOTA_OK;
1236 warn_put_all:
1237         spin_unlock(&dq_data_lock);
1238         /* Dirtify all the dquots - this can block when journalling */
1239         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1240                 if (transfer_from[cnt])
1241                         mark_dquot_dirty(transfer_from[cnt]);
1242                 if (transfer_to[cnt])
1243                         mark_dquot_dirty(transfer_to[cnt]);
1244         }
1245         flush_warnings(transfer_to, warntype);
1246
1247         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1248                 if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
1249                         dqput(transfer_from[cnt]);
1250                 if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
1251                         dqput(transfer_to[cnt]);
1252         }
1253         up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
1254         return ret;
1255 }
1256
1257 /*
1258  * Write info of quota file to disk
1259  */
1260 int dquot_commit_info(struct super_block *sb, int type)
1261 {
1262         int ret;
1263         struct quota_info *dqopt = sb_dqopt(sb);
1264
1265         down(&dqopt->dqio_sem);
1266         ret = dqopt->ops[type]->write_file_info(sb, type);
1267         up(&dqopt->dqio_sem);
1268         return ret;
1269 }
1270
1271 /*
1272  * Definitions of diskquota operations.
1273  */
1274 struct dquot_operations dquot_operations = {
1275         .initialize     = dquot_initialize,
1276         .drop           = dquot_drop,
1277         .alloc_space    = dquot_alloc_space,
1278         .alloc_inode    = dquot_alloc_inode,
1279         .free_space     = dquot_free_space,
1280         .free_inode     = dquot_free_inode,
1281         .transfer       = dquot_transfer,
1282         .write_dquot    = dquot_commit,
1283         .acquire_dquot  = dquot_acquire,
1284         .release_dquot  = dquot_release,
1285         .mark_dirty     = dquot_mark_dquot_dirty,
1286         .write_info     = dquot_commit_info
1287 };
1288
1289 static inline void set_enable_flags(struct quota_info *dqopt, int type)
1290 {
1291         switch (type) {
1292                 case USRQUOTA:
1293                         dqopt->flags |= DQUOT_USR_ENABLED;
1294                         break;
1295                 case GRPQUOTA:
1296                         dqopt->flags |= DQUOT_GRP_ENABLED;
1297                         break;
1298         }
1299 }
1300
1301 static inline void reset_enable_flags(struct quota_info *dqopt, int type)
1302 {
1303         switch (type) {
1304                 case USRQUOTA:
1305                         dqopt->flags &= ~DQUOT_USR_ENABLED;
1306                         break;
1307                 case GRPQUOTA:
1308                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
1309                         break;
1310         }
1311 }
1312
1313 /*
1314  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
1315  */
1316 int vfs_quota_off(struct super_block *sb, int type)
1317 {
1318         int cnt;
1319         struct quota_info *dqopt = sb_dqopt(sb);
1320
1321         /* We need to serialize quota_off() for device */
1322         down(&dqopt->dqonoff_sem);
1323         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1324                 if (type != -1 && cnt != type)
1325                         continue;
1326                 if (!sb_has_quota_enabled(sb, cnt))
1327                         continue;
1328                 reset_enable_flags(dqopt, cnt);
1329
1330                 /* Note: these are blocking operations */
1331                 drop_dquot_ref(sb, cnt);
1332                 invalidate_dquots(sb, cnt);
1333                 /*
1334                  * Now all dquots should be invalidated, all writes done so we should be only
1335                  * users of the info. No locks needed.
1336                  */
1337                 if (info_dirty(&dqopt->info[cnt]))
1338                         sb->dq_op->write_info(sb, cnt);
1339                 if (dqopt->ops[cnt]->free_file_info)
1340                         dqopt->ops[cnt]->free_file_info(sb, cnt);
1341                 put_quota_format(dqopt->info[cnt].dqi_format);
1342
1343                 fput(dqopt->files[cnt]);
1344                 dqopt->files[cnt] = NULL;
1345                 dqopt->info[cnt].dqi_flags = 0;
1346                 dqopt->info[cnt].dqi_igrace = 0;
1347                 dqopt->info[cnt].dqi_bgrace = 0;
1348                 dqopt->ops[cnt] = NULL;
1349         }
1350         up(&dqopt->dqonoff_sem);
1351         return 0;
1352 }
1353
1354 /*
1355  *      Turn quotas on on a device
1356  */
1357
1358 /* Helper function when we already have file open */
1359 static int vfs_quota_on_file(struct file *f, int type, int format_id)
1360 {
1361         struct quota_format_type *fmt = find_quota_format(format_id);
1362         struct inode *inode;
1363         struct super_block *sb = f->f_dentry->d_sb;
1364         struct quota_info *dqopt = sb_dqopt(sb);
1365         struct dquot *to_drop[MAXQUOTAS];
1366         int error, cnt;
1367         unsigned int oldflags;
1368
1369         if (!fmt)
1370                 return -ESRCH;
1371         error = -EIO;
1372         if (!f->f_op || !f->f_op->read || !f->f_op->write)
1373                 goto out_fmt;
1374         inode = f->f_dentry->d_inode;
1375         error = -EACCES;
1376         if (!S_ISREG(inode->i_mode))
1377                 goto out_fmt;
1378
1379         down(&dqopt->dqonoff_sem);
1380         if (sb_has_quota_enabled(sb, type)) {
1381                 error = -EBUSY;
1382                 goto out_lock;
1383         }
1384         oldflags = inode->i_flags;
1385         dqopt->files[type] = f;
1386         error = -EINVAL;
1387         if (!fmt->qf_ops->check_quota_file(sb, type))
1388                 goto out_file_init;
1389         /* We don't want quota and atime on quota files (deadlocks possible)
1390          * We also need to set GFP mask differently because we cannot recurse
1391          * into filesystem when allocating page for quota inode */
1392         down_write(&dqopt->dqptr_sem);
1393         inode->i_flags |= S_NOQUOTA | S_NOATIME;
1394
1395         /*
1396          * We write to quota files deep within filesystem code.  We don't want
1397          * the VFS to reenter filesystem code when it tries to allocate a
1398          * pagecache page for the quota file write.  So clear __GFP_FS in
1399          * the quota file's allocation flags.
1400          */
1401         mapping_set_gfp_mask(inode->i_mapping,
1402                 mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
1403
1404         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1405                 to_drop[cnt] = inode->i_dquot[cnt];
1406                 inode->i_dquot[cnt] = NODQUOT;
1407         }
1408         inode->i_flags &= ~S_QUOTA;
1409         up_write(&dqopt->dqptr_sem);
1410         /* We must put dquots outside of dqptr_sem because we may need to
1411          * start transaction for dquot_release() */
1412         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
1413                 if (to_drop[cnt])
1414                         dqput(to_drop[cnt]);
1415         }
1416
1417         dqopt->ops[type] = fmt->qf_ops;
1418         dqopt->info[type].dqi_format = fmt;
1419         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
1420         down(&dqopt->dqio_sem);
1421         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
1422                 up(&dqopt->dqio_sem);
1423                 goto out_file_init;
1424         }
1425         up(&dqopt->dqio_sem);
1426         set_enable_flags(dqopt, type);
1427
1428         add_dquot_ref(sb, type);
1429         up(&dqopt->dqonoff_sem);
1430
1431         return 0;
1432
1433 out_file_init:
1434         inode->i_flags = oldflags;
1435         dqopt->files[type] = NULL;
1436 out_lock:
1437         up_write(&dqopt->dqptr_sem);
1438         up(&dqopt->dqonoff_sem);
1439 out_fmt:
1440         put_quota_format(fmt);
1441
1442         return error;
1443 }
1444
1445 /* Actual function called from quotactl() */
1446 int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
1447 {
1448         struct file *f;
1449         int error;
1450
1451         f = filp_open(path, O_RDWR, 0600);
1452         if (IS_ERR(f))
1453                 return PTR_ERR(f);
1454         error = security_quota_on(f);
1455         if (error)
1456                 goto out_f;
1457         error = vfs_quota_on_file(f, type, format_id);
1458         if (!error)
1459                 return 0;
1460 out_f:
1461         filp_close(f, NULL);
1462         return error;
1463 }
1464
1465 /*
1466  * Function used by filesystems when filp_open() would fail (filesystem is
1467  * being mounted now). We will use a private file structure. Caller is
1468  * responsible that it's IO functions won't need vfsmnt structure or
1469  * some dentry tricks...
1470  */
1471 int vfs_quota_on_mount(int type, int format_id, struct dentry *dentry)
1472 {
1473         struct file *f;
1474         int error;
1475
1476         dget(dentry);   /* Get a reference for struct file */
1477         f = dentry_open(dentry, NULL, O_RDWR);
1478         if (IS_ERR(f)) {
1479                 error = PTR_ERR(f);
1480                 goto out_dentry;
1481         }
1482         error = vfs_quota_on_file(f, type, format_id);
1483         if (!error)
1484                 return 0;
1485         fput(f);
1486 out_dentry:
1487         dput(dentry);
1488         return error;
1489 }
1490
1491 /* Generic routine for getting common part of quota structure */
1492 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
1493 {
1494         struct mem_dqblk *dm = &dquot->dq_dqb;
1495
1496         spin_lock(&dq_data_lock);
1497         di->dqb_bhardlimit = dm->dqb_bhardlimit;
1498         di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
1499         di->dqb_curspace = dm->dqb_curspace;
1500         di->dqb_ihardlimit = dm->dqb_ihardlimit;
1501         di->dqb_isoftlimit = dm->dqb_isoftlimit;
1502         di->dqb_curinodes = dm->dqb_curinodes;
1503         di->dqb_btime = dm->dqb_btime;
1504         di->dqb_itime = dm->dqb_itime;
1505         di->dqb_valid = QIF_ALL;
1506         spin_unlock(&dq_data_lock);
1507 }
1508
1509 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1510 {
1511         struct dquot *dquot;
1512
1513         down(&sb_dqopt(sb)->dqonoff_sem);
1514         if (!(dquot = dqget(sb, id, type))) {
1515                 up(&sb_dqopt(sb)->dqonoff_sem);
1516                 return -ESRCH;
1517         }
1518         do_get_dqblk(dquot, di);
1519         dqput(dquot);
1520         up(&sb_dqopt(sb)->dqonoff_sem);
1521         return 0;
1522 }
1523
1524 /* Generic routine for setting common part of quota structure */
1525 static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
1526 {
1527         struct mem_dqblk *dm = &dquot->dq_dqb;
1528         int check_blim = 0, check_ilim = 0;
1529
1530         spin_lock(&dq_data_lock);
1531         if (di->dqb_valid & QIF_SPACE) {
1532                 dm->dqb_curspace = di->dqb_curspace;
1533                 check_blim = 1;
1534         }
1535         if (di->dqb_valid & QIF_BLIMITS) {
1536                 dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
1537                 dm->dqb_bhardlimit = di->dqb_bhardlimit;
1538                 check_blim = 1;
1539         }
1540         if (di->dqb_valid & QIF_INODES) {
1541                 dm->dqb_curinodes = di->dqb_curinodes;
1542                 check_ilim = 1;
1543         }
1544         if (di->dqb_valid & QIF_ILIMITS) {
1545                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
1546                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
1547                 check_ilim = 1;
1548         }
1549         if (di->dqb_valid & QIF_BTIME)
1550                 dm->dqb_btime = di->dqb_btime;
1551         if (di->dqb_valid & QIF_ITIME)
1552                 dm->dqb_itime = di->dqb_itime;
1553
1554         if (check_blim) {
1555                 if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
1556                         dm->dqb_btime = 0;
1557                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
1558                 }
1559                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
1560                         dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
1561         }
1562         if (check_ilim) {
1563                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
1564                         dm->dqb_itime = 0;
1565                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
1566                 }
1567                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
1568                         dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
1569         }
1570         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
1571                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
1572         else
1573                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
1574         spin_unlock(&dq_data_lock);
1575         mark_dquot_dirty(dquot);
1576 }
1577
1578 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
1579 {
1580         struct dquot *dquot;
1581
1582         down(&sb_dqopt(sb)->dqonoff_sem);
1583         if (!(dquot = dqget(sb, id, type))) {
1584                 up(&sb_dqopt(sb)->dqonoff_sem);
1585                 return -ESRCH;
1586         }
1587         do_set_dqblk(dquot, di);
1588         dqput(dquot);
1589         up(&sb_dqopt(sb)->dqonoff_sem);
1590         return 0;
1591 }
1592
1593 /* Generic routine for getting common part of quota file information */
1594 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1595 {
1596         struct mem_dqinfo *mi;
1597
1598         down(&sb_dqopt(sb)->dqonoff_sem);
1599         if (!sb_has_quota_enabled(sb, type)) {
1600                 up(&sb_dqopt(sb)->dqonoff_sem);
1601                 return -ESRCH;
1602         }
1603         mi = sb_dqopt(sb)->info + type;
1604         spin_lock(&dq_data_lock);
1605         ii->dqi_bgrace = mi->dqi_bgrace;
1606         ii->dqi_igrace = mi->dqi_igrace;
1607         ii->dqi_flags = mi->dqi_flags & DQF_MASK;
1608         ii->dqi_valid = IIF_ALL;
1609         spin_unlock(&dq_data_lock);
1610         up(&sb_dqopt(sb)->dqonoff_sem);
1611         return 0;
1612 }
1613
1614 /* Generic routine for setting common part of quota file information */
1615 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
1616 {
1617         struct mem_dqinfo *mi;
1618
1619         down(&sb_dqopt(sb)->dqonoff_sem);
1620         if (!sb_has_quota_enabled(sb, type)) {
1621                 up(&sb_dqopt(sb)->dqonoff_sem);
1622                 return -ESRCH;
1623         }
1624         mi = sb_dqopt(sb)->info + type;
1625         spin_lock(&dq_data_lock);
1626         if (ii->dqi_valid & IIF_BGRACE)
1627                 mi->dqi_bgrace = ii->dqi_bgrace;
1628         if (ii->dqi_valid & IIF_IGRACE)
1629                 mi->dqi_igrace = ii->dqi_igrace;
1630         if (ii->dqi_valid & IIF_FLAGS)
1631                 mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
1632         spin_unlock(&dq_data_lock);
1633         mark_info_dirty(sb, type);
1634         /* Force write to disk */
1635         sb->dq_op->write_info(sb, type);
1636         up(&sb_dqopt(sb)->dqonoff_sem);
1637         return 0;
1638 }
1639
1640 struct quotactl_ops vfs_quotactl_ops = {
1641         .quota_on       = vfs_quota_on,
1642         .quota_off      = vfs_quota_off,
1643         .quota_sync     = vfs_quota_sync,
1644         .get_info       = vfs_get_dqinfo,
1645         .set_info       = vfs_set_dqinfo,
1646         .get_dqblk      = vfs_get_dqblk,
1647         .set_dqblk      = vfs_set_dqblk
1648 };
1649
1650 static ctl_table fs_dqstats_table[] = {
1651         {
1652                 .ctl_name       = FS_DQ_LOOKUPS,
1653                 .procname       = "lookups",
1654                 .data           = &dqstats.lookups,
1655                 .maxlen         = sizeof(int),
1656                 .mode           = 0444,
1657                 .proc_handler   = &proc_dointvec,
1658         },
1659         {
1660                 .ctl_name       = FS_DQ_DROPS,
1661                 .procname       = "drops",
1662                 .data           = &dqstats.drops,
1663                 .maxlen         = sizeof(int),
1664                 .mode           = 0444,
1665                 .proc_handler   = &proc_dointvec,
1666         },
1667         {
1668                 .ctl_name       = FS_DQ_READS,
1669                 .procname       = "reads",
1670                 .data           = &dqstats.reads,
1671                 .maxlen         = sizeof(int),
1672                 .mode           = 0444,
1673                 .proc_handler   = &proc_dointvec,
1674         },
1675         {
1676                 .ctl_name       = FS_DQ_WRITES,
1677                 .procname       = "writes",
1678                 .data           = &dqstats.writes,
1679                 .maxlen         = sizeof(int),
1680                 .mode           = 0444,
1681                 .proc_handler   = &proc_dointvec,
1682         },
1683         {
1684                 .ctl_name       = FS_DQ_CACHE_HITS,
1685                 .procname       = "cache_hits",
1686                 .data           = &dqstats.cache_hits,
1687                 .maxlen         = sizeof(int),
1688                 .mode           = 0444,
1689                 .proc_handler   = &proc_dointvec,
1690         },
1691         {
1692                 .ctl_name       = FS_DQ_ALLOCATED,
1693                 .procname       = "allocated_dquots",
1694                 .data           = &dqstats.allocated_dquots,
1695                 .maxlen         = sizeof(int),
1696                 .mode           = 0444,
1697                 .proc_handler   = &proc_dointvec,
1698         },
1699         {
1700                 .ctl_name       = FS_DQ_FREE,
1701                 .procname       = "free_dquots",
1702                 .data           = &dqstats.free_dquots,
1703                 .maxlen         = sizeof(int),
1704                 .mode           = 0444,
1705                 .proc_handler   = &proc_dointvec,
1706         },
1707         {
1708                 .ctl_name       = FS_DQ_SYNCS,
1709                 .procname       = "syncs",
1710                 .data           = &dqstats.syncs,
1711                 .maxlen         = sizeof(int),
1712                 .mode           = 0444,
1713                 .proc_handler   = &proc_dointvec,
1714         },
1715         { .ctl_name = 0 },
1716 };
1717
1718 static ctl_table fs_table[] = {
1719         {
1720                 .ctl_name       = FS_DQSTATS,
1721                 .procname       = "quota",
1722                 .mode           = 0555,
1723                 .child          = fs_dqstats_table,
1724         },
1725         { .ctl_name = 0 },
1726 };
1727
1728 static ctl_table sys_table[] = {
1729         {
1730                 .ctl_name       = CTL_FS,
1731                 .procname       = "fs",
1732                 .mode           = 0555,
1733                 .child          = fs_table,
1734         },
1735         { .ctl_name = 0 },
1736 };
1737
1738 /* SLAB cache for dquot structures */
1739 kmem_cache_t *dquot_cachep;
1740
1741 static int __init dquot_init(void)
1742 {
1743         int i;
1744         unsigned long nr_hash, order;
1745
1746         printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
1747
1748         register_sysctl_table(sys_table, 0);
1749
1750         dquot_cachep = kmem_cache_create("dquot",
1751                         sizeof(struct dquot), sizeof(unsigned long) * 4,
1752                         SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
1753                         NULL, NULL);
1754
1755         order = 0;
1756         dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
1757         if (!dquot_hash)
1758                 panic("Cannot create dquot hash table");
1759
1760         /* Find power-of-two hlist_heads which can fit into allocation */
1761         nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
1762         dq_hash_bits = 0;
1763         do {
1764                 dq_hash_bits++;
1765         } while (nr_hash >> dq_hash_bits);
1766         dq_hash_bits--;
1767
1768         nr_hash = 1UL << dq_hash_bits;
1769         dq_hash_mask = nr_hash - 1;
1770         for (i = 0; i < nr_hash; i++)
1771                 INIT_HLIST_HEAD(dquot_hash + i);
1772
1773         printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
1774                         nr_hash, order, (PAGE_SIZE << order));
1775
1776         set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
1777
1778         return 0;
1779 }
1780 module_init(dquot_init);
1781
1782 EXPORT_SYMBOL(register_quota_format);
1783 EXPORT_SYMBOL(unregister_quota_format);
1784 EXPORT_SYMBOL(dqstats);
1785 EXPORT_SYMBOL(dq_list_lock);
1786 EXPORT_SYMBOL(dq_data_lock);
1787 EXPORT_SYMBOL(vfs_quota_on);
1788 EXPORT_SYMBOL(vfs_quota_on_mount);
1789 EXPORT_SYMBOL(vfs_quota_off);
1790 EXPORT_SYMBOL(vfs_quota_sync);
1791 EXPORT_SYMBOL(vfs_get_dqinfo);
1792 EXPORT_SYMBOL(vfs_set_dqinfo);
1793 EXPORT_SYMBOL(vfs_get_dqblk);
1794 EXPORT_SYMBOL(vfs_set_dqblk);
1795 EXPORT_SYMBOL(dquot_commit);
1796 EXPORT_SYMBOL(dquot_commit_info);
1797 EXPORT_SYMBOL(dquot_acquire);
1798 EXPORT_SYMBOL(dquot_release);
1799 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
1800 EXPORT_SYMBOL(dquot_initialize);
1801 EXPORT_SYMBOL(dquot_drop);
1802 EXPORT_SYMBOL(dquot_alloc_space);
1803 EXPORT_SYMBOL(dquot_alloc_inode);
1804 EXPORT_SYMBOL(dquot_free_space);
1805 EXPORT_SYMBOL(dquot_free_inode);
1806 EXPORT_SYMBOL(dquot_transfer);