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