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dquot.c

/*
 * Implementation of the diskquota system for the LINUX operating system. QUOTA
 * is implemented using the BSD system call interface as the means of
 * communication with the user level. This file contains the generic routines
 * called by the different filesystems on allocation of an inode or block.
 * These routines take care of the administration needed to have a consistent
 * diskquota tracking system. The ideas of both user and group quotas are based
 * on the Melbourne quota system as used on BSD derived systems. The internal
 * implementation is based on one of the several variants of the LINUX
 * inode-subsystem with added complexity of the diskquota system.
 * 
 * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
 * 
 * Author:  Marco van Wieringen <mvw@planets.elm.net>
 *
 * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
 *
 *          Revised list management to avoid races
 *          -- Bill Hawes, <whawes@star.net>, 9/98
 *
 *          Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
 *          As the consequence the locking was moved from dquot_decr_...(),
 *          dquot_incr_...() to calling functions.
 *          invalidate_dquots() now writes modified dquots.
 *          Serialized quota_off() and quota_on() for mount point.
 *          Fixed a few bugs in grow_dquots().
 *          Fixed deadlock in write_dquot() - we no longer account quotas on
 *          quota files
 *          remove_dquot_ref() moved to inode.c - it now traverses through inodes
 *          add_dquot_ref() restarts after blocking
 *          Added check for bogus uid and fixed check for group in quotactl.
 *          Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
 *
 *          Used struct list_head instead of own list struct
 *          Invalidation of referenced dquots is no longer possible
 *          Improved free_dquots list management
 *          Quota and i_blocks are now updated in one place to avoid races
 *          Warnings are now delayed so we won't block in critical section
 *          Write updated not to require dquot lock
 *          Jan Kara, <jack@suse.cz>, 9/2000
 *
 *          Added dynamic quota structure allocation
 *          Jan Kara <jack@suse.cz> 12/2000
 *
 *          Rewritten quota interface. Implemented new quota format and
 *          formats registering.
 *          Jan Kara, <jack@suse.cz>, 2001,2002
 *
 *          New SMP locking.
 *          Jan Kara, <jack@suse.cz>, 10/2002
 *
 *          Added journalled quota support, fix lock inversion problems
 *          Jan Kara, <jack@suse.cz>, 2003,2004
 *
 * (C) Copyright 1994 - 1997 Marco van Wieringen 
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/kmod.h>
#include <linux/namei.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/writeback.h> /* for inode_lock, oddly enough.. */
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
#include <net/netlink.h>
#include <net/genetlink.h>
#endif

#include <asm/uaccess.h>

#define __DQUOT_PARANOIA

/*
 * There are two quota SMP locks. dq_list_lock protects all lists with quotas
 * and quota formats and also dqstats structure containing statistics about the
 * lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
 * and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
 * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
 * in inode_add_bytes() and inode_sub_bytes().
 *
 * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
 *
 * Note that some things (eg. sb pointer, type, id) doesn't change during
 * the life of the dquot structure and so needn't to be protected by a lock
 *
 * Any operation working on dquots via inode pointers must hold dqptr_sem.  If
 * operation is just reading pointers from inode (or not using them at all) the
 * read lock is enough. If pointers are altered function must hold write lock
 * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
 * for altering the flag i_mutex is also needed).  If operation is holding
 * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
 * dqonoff_mutex.
 * This locking assures that:
 *   a) update/access to dquot pointers in inode is serialized
 *   b) everyone is guarded against invalidate_dquots()
 *
 * Each dquot has its dq_lock mutex. Locked dquots might not be referenced
 * from inodes (dquot_alloc_space() and such don't check the dq_lock).
 * Currently dquot is locked only when it is being read to memory (or space for
 * it is being allocated) on the first dqget() and when it is being released on
 * the last dqput(). The allocation and release oparations are serialized by
 * the dq_lock and by checking the use count in dquot_release().  Write
 * operations on dquots don't hold dq_lock as they copy data under dq_data_lock
 * spinlock to internal buffers before writing.
 *
 * Lock ordering (including related VFS locks) is the following:
 *   i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
 *   dqio_mutex
 * i_mutex on quota files is special (it's below dqio_mutex)
 */

static DEFINE_SPINLOCK(dq_list_lock);
DEFINE_SPINLOCK(dq_data_lock);

static char *quotatypes[] = INITQFNAMES;
static struct quota_format_type *quota_formats; /* List of registered formats */
static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;

/* SLAB cache for dquot structures */
static struct kmem_cache *dquot_cachep;

int register_quota_format(struct quota_format_type *fmt)
{
      spin_lock(&dq_list_lock);
      fmt->qf_next = quota_formats;
      quota_formats = fmt;
      spin_unlock(&dq_list_lock);
      return 0;
}

void unregister_quota_format(struct quota_format_type *fmt)
{
      struct quota_format_type **actqf;

      spin_lock(&dq_list_lock);
      for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
      if (*actqf)
            *actqf = (*actqf)->qf_next;
      spin_unlock(&dq_list_lock);
}

static struct quota_format_type *find_quota_format(int id)
{
      struct quota_format_type *actqf;

      spin_lock(&dq_list_lock);
      for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
      if (!actqf || !try_module_get(actqf->qf_owner)) {
            int qm;

            spin_unlock(&dq_list_lock);
            
            for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
            if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
                  return NULL;

            spin_lock(&dq_list_lock);
            for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
            if (actqf && !try_module_get(actqf->qf_owner))
                  actqf = NULL;
      }
      spin_unlock(&dq_list_lock);
      return actqf;
}

static void put_quota_format(struct quota_format_type *fmt)
{
      module_put(fmt->qf_owner);
}

/*
 * Dquot List Management:
 * The quota code uses three lists for dquot management: the inuse_list,
 * free_dquots, and dquot_hash[] array. A single dquot structure may be
 * on all three lists, depending on its current state.
 *
 * All dquots are placed to the end of inuse_list when first created, and this
 * list is used for invalidate operation, which must look at every dquot.
 *
 * Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
 * and this list is searched whenever we need an available dquot.  Dquots are
 * removed from the list as soon as they are used again, and
 * dqstats.free_dquots gives the number of dquots on the list. When
 * dquot is invalidated it's completely released from memory.
 *
 * Dquots with a specific identity (device, type and id) are placed on
 * one of the dquot_hash[] hash chains. The provides an efficient search
 * mechanism to locate a specific dquot.
 */

static LIST_HEAD(inuse_list);
static LIST_HEAD(free_dquots);
static unsigned int dq_hash_bits, dq_hash_mask;
static struct hlist_head *dquot_hash;

struct dqstats dqstats;

static void dqput(struct dquot *dquot);

static inline unsigned int
hashfn(const struct super_block *sb, unsigned int id, int type)
{
      unsigned long tmp;

      tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
      return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
}

/*
 * Following list functions expect dq_list_lock to be held
 */
static inline void insert_dquot_hash(struct dquot *dquot)
{
      struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
      hlist_add_head(&dquot->dq_hash, head);
}

static inline void remove_dquot_hash(struct dquot *dquot)
{
      hlist_del_init(&dquot->dq_hash);
}

static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
{
      struct hlist_node *node;
      struct dquot *dquot;

      hlist_for_each (node, dquot_hash+hashent) {
            dquot = hlist_entry(node, struct dquot, dq_hash);
            if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
                  return dquot;
      }
      return NODQUOT;
}

/* Add a dquot to the tail of the free list */
static inline void put_dquot_last(struct dquot *dquot)
{
      list_add_tail(&dquot->dq_free, &free_dquots);
      dqstats.free_dquots++;
}

static inline void remove_free_dquot(struct dquot *dquot)
{
      if (list_empty(&dquot->dq_free))
            return;
      list_del_init(&dquot->dq_free);
      dqstats.free_dquots--;
}

static inline void put_inuse(struct dquot *dquot)
{
      /* We add to the back of inuse list so we don't have to restart
       * when traversing this list and we block */
      list_add_tail(&dquot->dq_inuse, &inuse_list);
      dqstats.allocated_dquots++;
}

static inline void remove_inuse(struct dquot *dquot)
{
      dqstats.allocated_dquots--;
      list_del(&dquot->dq_inuse);
}
/*
 * End of list functions needing dq_list_lock
 */

static void wait_on_dquot(struct dquot *dquot)
{
      mutex_lock(&dquot->dq_lock);
      mutex_unlock(&dquot->dq_lock);
}

#define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))

int dquot_mark_dquot_dirty(struct dquot *dquot)
{
      spin_lock(&dq_list_lock);
      if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
            list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
                        info[dquot->dq_type].dqi_dirty_list);
      spin_unlock(&dq_list_lock);
      return 0;
}

/* This function needs dq_list_lock */
static inline int clear_dquot_dirty(struct dquot *dquot)
{
      if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
            return 0;
      list_del_init(&dquot->dq_dirty);
      return 1;
}

void mark_info_dirty(struct super_block *sb, int type)
{
      set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
}
EXPORT_SYMBOL(mark_info_dirty);

/*
 *    Read dquot from disk and alloc space for it
 */

int dquot_acquire(struct dquot *dquot)
{
      int ret = 0, ret2 = 0;
      struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

      mutex_lock(&dquot->dq_lock);
      mutex_lock(&dqopt->dqio_mutex);
      if (!test_bit(DQ_READ_B, &dquot->dq_flags))
            ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
      if (ret < 0)
            goto out_iolock;
      set_bit(DQ_READ_B, &dquot->dq_flags);
      /* Instantiate dquot if needed */
      if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
            ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
            /* Write the info if needed */
            if (info_dirty(&dqopt->info[dquot->dq_type]))
                  ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
            if (ret < 0)
                  goto out_iolock;
            if (ret2 < 0) {
                  ret = ret2;
                  goto out_iolock;
            }
      }
      set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_iolock:
      mutex_unlock(&dqopt->dqio_mutex);
      mutex_unlock(&dquot->dq_lock);
      return ret;
}

/*
 *    Write dquot to disk
 */
int dquot_commit(struct dquot *dquot)
{
      int ret = 0, ret2 = 0;
      struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

      mutex_lock(&dqopt->dqio_mutex);
      spin_lock(&dq_list_lock);
      if (!clear_dquot_dirty(dquot)) {
            spin_unlock(&dq_list_lock);
            goto out_sem;
      }
      spin_unlock(&dq_list_lock);
      /* Inactive dquot can be only if there was error during read/init
       * => we have better not writing it */
      if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
            ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
            if (info_dirty(&dqopt->info[dquot->dq_type]))
                  ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
            if (ret >= 0)
                  ret = ret2;
      }
out_sem:
      mutex_unlock(&dqopt->dqio_mutex);
      return ret;
}

/*
 *    Release dquot
 */
int dquot_release(struct dquot *dquot)
{
      int ret = 0, ret2 = 0;
      struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);

      mutex_lock(&dquot->dq_lock);
      /* Check whether we are not racing with some other dqget() */
      if (atomic_read(&dquot->dq_count) > 1)
            goto out_dqlock;
      mutex_lock(&dqopt->dqio_mutex);
      if (dqopt->ops[dquot->dq_type]->release_dqblk) {
            ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
            /* Write the info */
            if (info_dirty(&dqopt->info[dquot->dq_type]))
                  ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
            if (ret >= 0)
                  ret = ret2;
      }
      clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
      mutex_unlock(&dqopt->dqio_mutex);
out_dqlock:
      mutex_unlock(&dquot->dq_lock);
      return ret;
}

/* Invalidate all dquots on the list. Note that this function is called after
 * quota is disabled and pointers from inodes removed so there cannot be new
 * quota users. There can still be some users of quotas due to inodes being
 * just deleted or pruned by prune_icache() (those are not attached to any
 * list). We have to wait for such users.
 */
static void invalidate_dquots(struct super_block *sb, int type)
{
      struct dquot *dquot, *tmp;

restart:
      spin_lock(&dq_list_lock);
      list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
            if (dquot->dq_sb != sb)
                  continue;
            if (dquot->dq_type != type)
                  continue;
            /* Wait for dquot users */
            if (atomic_read(&dquot->dq_count)) {
                  DEFINE_WAIT(wait);

                  atomic_inc(&dquot->dq_count);
                  prepare_to_wait(&dquot->dq_wait_unused, &wait,
                              TASK_UNINTERRUPTIBLE);
                  spin_unlock(&dq_list_lock);
                  /* Once dqput() wakes us up, we know it's time to free
                   * the dquot.
                   * IMPORTANT: we rely on the fact that there is always
                   * at most one process waiting for dquot to free.
                   * Otherwise dq_count would be > 1 and we would never
                   * wake up.
                   */
                  if (atomic_read(&dquot->dq_count) > 1)
                        schedule();
                  finish_wait(&dquot->dq_wait_unused, &wait);
                  dqput(dquot);
                  /* At this moment dquot() need not exist (it could be
                   * reclaimed by prune_dqcache(). Hence we must
                   * restart. */
                  goto restart;
            }
            /*
             * Quota now has no users and it has been written on last
             * dqput()
             */
            remove_dquot_hash(dquot);
            remove_free_dquot(dquot);
            remove_inuse(dquot);
            kmem_cache_free(dquot_cachep, dquot);
      }
      spin_unlock(&dq_list_lock);
}

int vfs_quota_sync(struct super_block *sb, int type)
{
      struct list_head *dirty;
      struct dquot *dquot;
      struct quota_info *dqopt = sb_dqopt(sb);
      int cnt;

      mutex_lock(&dqopt->dqonoff_mutex);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (type != -1 && cnt != type)
                  continue;
            if (!sb_has_quota_enabled(sb, cnt))
                  continue;
            spin_lock(&dq_list_lock);
            dirty = &dqopt->info[cnt].dqi_dirty_list;
            while (!list_empty(dirty)) {
                  dquot = list_first_entry(dirty, struct dquot, dq_dirty);
                  /* Dirty and inactive can be only bad dquot... */
                  if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
                        clear_dquot_dirty(dquot);
                        continue;
                  }
                  /* Now we have active dquot from which someone is
                   * holding reference so we can safely just increase
                   * use count */
                  atomic_inc(&dquot->dq_count);
                  dqstats.lookups++;
                  spin_unlock(&dq_list_lock);
                  sb->dq_op->write_dquot(dquot);
                  dqput(dquot);
                  spin_lock(&dq_list_lock);
            }
            spin_unlock(&dq_list_lock);
      }

      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
                  && info_dirty(&dqopt->info[cnt]))
                  sb->dq_op->write_info(sb, cnt);
      spin_lock(&dq_list_lock);
      dqstats.syncs++;
      spin_unlock(&dq_list_lock);
      mutex_unlock(&dqopt->dqonoff_mutex);

      return 0;
}

/* Free unused dquots from cache */
static void prune_dqcache(int count)
{
      struct list_head *head;
      struct dquot *dquot;

      head = free_dquots.prev;
      while (head != &free_dquots && count) {
            dquot = list_entry(head, struct dquot, dq_free);
            remove_dquot_hash(dquot);
            remove_free_dquot(dquot);
            remove_inuse(dquot);
            kmem_cache_free(dquot_cachep, dquot);
            count--;
            head = free_dquots.prev;
      }
}

/*
 * This is called from kswapd when we think we need some
 * more memory
 */

static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
{
      if (nr) {
            spin_lock(&dq_list_lock);
            prune_dqcache(nr);
            spin_unlock(&dq_list_lock);
      }
      return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
}

static struct shrinker dqcache_shrinker = {
      .shrink = shrink_dqcache_memory,
      .seeks = DEFAULT_SEEKS,
};

/*
 * Put reference to dquot
 * NOTE: If you change this function please check whether dqput_blocks() works right...
 * MUST be called with either dqptr_sem or dqonoff_mutex held
 */
static void dqput(struct dquot *dquot)
{
      if (!dquot)
            return;
#ifdef __DQUOT_PARANOIA
      if (!atomic_read(&dquot->dq_count)) {
            printk("VFS: dqput: trying to free free dquot\n");
            printk("VFS: device %s, dquot of %s %d\n",
                  dquot->dq_sb->s_id,
                  quotatypes[dquot->dq_type],
                  dquot->dq_id);
            BUG();
      }
#endif
      
      spin_lock(&dq_list_lock);
      dqstats.drops++;
      spin_unlock(&dq_list_lock);
we_slept:
      spin_lock(&dq_list_lock);
      if (atomic_read(&dquot->dq_count) > 1) {
            /* We have more than one user... nothing to do */
            atomic_dec(&dquot->dq_count);
            /* Releasing dquot during quotaoff phase? */
            if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
                atomic_read(&dquot->dq_count) == 1)
                  wake_up(&dquot->dq_wait_unused);
            spin_unlock(&dq_list_lock);
            return;
      }
      /* Need to release dquot? */
      if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
            spin_unlock(&dq_list_lock);
            /* Commit dquot before releasing */
            dquot->dq_sb->dq_op->write_dquot(dquot);
            goto we_slept;
      }
      /* Clear flag in case dquot was inactive (something bad happened) */
      clear_dquot_dirty(dquot);
      if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
            spin_unlock(&dq_list_lock);
            dquot->dq_sb->dq_op->release_dquot(dquot);
            goto we_slept;
      }
      atomic_dec(&dquot->dq_count);
#ifdef __DQUOT_PARANOIA
      /* sanity check */
      BUG_ON(!list_empty(&dquot->dq_free));
#endif
      put_dquot_last(dquot);
      spin_unlock(&dq_list_lock);
}

static struct dquot *get_empty_dquot(struct super_block *sb, int type)
{
      struct dquot *dquot;

      dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
      if(!dquot)
            return NODQUOT;

      mutex_init(&dquot->dq_lock);
      INIT_LIST_HEAD(&dquot->dq_free);
      INIT_LIST_HEAD(&dquot->dq_inuse);
      INIT_HLIST_NODE(&dquot->dq_hash);
      INIT_LIST_HEAD(&dquot->dq_dirty);
      init_waitqueue_head(&dquot->dq_wait_unused);
      dquot->dq_sb = sb;
      dquot->dq_type = type;
      atomic_set(&dquot->dq_count, 1);

      return dquot;
}

/*
 * Get reference to dquot
 * MUST be called with either dqptr_sem or dqonoff_mutex held
 */
static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
{
      unsigned int hashent = hashfn(sb, id, type);
      struct dquot *dquot, *empty = NODQUOT;

        if (!sb_has_quota_enabled(sb, type))
            return NODQUOT;
we_slept:
      spin_lock(&dq_list_lock);
      if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
            if (empty == NODQUOT) {
                  spin_unlock(&dq_list_lock);
                  if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
                        schedule(); /* Try to wait for a moment... */
                  goto we_slept;
            }
            dquot = empty;
            dquot->dq_id = id;
            /* all dquots go on the inuse_list */
            put_inuse(dquot);
            /* hash it first so it can be found */
            insert_dquot_hash(dquot);
            dqstats.lookups++;
            spin_unlock(&dq_list_lock);
      } else {
            if (!atomic_read(&dquot->dq_count))
                  remove_free_dquot(dquot);
            atomic_inc(&dquot->dq_count);
            dqstats.cache_hits++;
            dqstats.lookups++;
            spin_unlock(&dq_list_lock);
            if (empty)
                  kmem_cache_free(dquot_cachep, empty);
      }
      /* Wait for dq_lock - after this we know that either dquot_release() is already
       * finished or it will be canceled due to dq_count > 1 test */
      wait_on_dquot(dquot);
      /* Read the dquot and instantiate it (everything done only if needed) */
      if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
            dqput(dquot);
            return NODQUOT;
      }
#ifdef __DQUOT_PARANOIA
      BUG_ON(!dquot->dq_sb);  /* Has somebody invalidated entry under us? */
#endif

      return dquot;
}

static int dqinit_needed(struct inode *inode, int type)
{
      int cnt;

      if (IS_NOQUOTA(inode))
            return 0;
      if (type != -1)
            return inode->i_dquot[type] == NODQUOT;
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            if (inode->i_dquot[cnt] == NODQUOT)
                  return 1;
      return 0;
}

/* This routine is guarded by dqonoff_mutex mutex */
static void add_dquot_ref(struct super_block *sb, int type)
{
      struct inode *inode;

restart:
      spin_lock(&inode_lock);
      list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
            if (!atomic_read(&inode->i_writecount))
                  continue;
            if (!dqinit_needed(inode, type))
                  continue;
            if (inode->i_state & (I_FREEING|I_WILL_FREE))
                  continue;

            __iget(inode);
            spin_unlock(&inode_lock);

            sb->dq_op->initialize(inode, type);
            iput(inode);
            /* As we may have blocked we had better restart... */
            goto restart;
      }
      spin_unlock(&inode_lock);
}

/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
static inline int dqput_blocks(struct dquot *dquot)
{
      if (atomic_read(&dquot->dq_count) <= 1)
            return 1;
      return 0;
}

/* Remove references to dquots from inode - add dquot to list for freeing if needed */
/* We can't race with anybody because we hold dqptr_sem for writing... */
static int remove_inode_dquot_ref(struct inode *inode, int type,
                          struct list_head *tofree_head)
{
      struct dquot *dquot = inode->i_dquot[type];

      inode->i_dquot[type] = NODQUOT;
      if (dquot != NODQUOT) {
            if (dqput_blocks(dquot)) {
#ifdef __DQUOT_PARANOIA
                  if (atomic_read(&dquot->dq_count) != 1)
                        printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
#endif
                  spin_lock(&dq_list_lock);
                  list_add(&dquot->dq_free, tofree_head);   /* As dquot must have currently users it can't be on the free list... */
                  spin_unlock(&dq_list_lock);
                  return 1;
            }
            else
                  dqput(dquot);   /* We have guaranteed we won't block */
      }
      return 0;
}

/* Free list of dquots - called from inode.c */
/* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
static void put_dquot_list(struct list_head *tofree_head)
{
      struct list_head *act_head;
      struct dquot *dquot;

      act_head = tofree_head->next;
      /* So now we have dquots on the list... Just free them */
      while (act_head != tofree_head) {
            dquot = list_entry(act_head, struct dquot, dq_free);
            act_head = act_head->next;
            list_del_init(&dquot->dq_free);     /* Remove dquot from the list so we won't have problems... */
            dqput(dquot);
      }
}

static void remove_dquot_ref(struct super_block *sb, int type,
            struct list_head *tofree_head)
{
      struct inode *inode;

      spin_lock(&inode_lock);
      list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
            if (!IS_NOQUOTA(inode))
                  remove_inode_dquot_ref(inode, type, tofree_head);
      }
      spin_unlock(&inode_lock);
}

/* Gather all references from inodes and drop them */
static void drop_dquot_ref(struct super_block *sb, int type)
{
      LIST_HEAD(tofree_head);

      if (sb->dq_op) {
            down_write(&sb_dqopt(sb)->dqptr_sem);
            remove_dquot_ref(sb, type, &tofree_head);
            up_write(&sb_dqopt(sb)->dqptr_sem);
            put_dquot_list(&tofree_head);
      }
}

static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
{
      dquot->dq_dqb.dqb_curinodes += number;
}

static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
{
      dquot->dq_dqb.dqb_curspace += number;
}

static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
{
      if (dquot->dq_dqb.dqb_curinodes > number)
            dquot->dq_dqb.dqb_curinodes -= number;
      else
            dquot->dq_dqb.dqb_curinodes = 0;
      if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
            dquot->dq_dqb.dqb_itime = (time_t) 0;
      clear_bit(DQ_INODES_B, &dquot->dq_flags);
}

static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
{
      if (dquot->dq_dqb.dqb_curspace > number)
            dquot->dq_dqb.dqb_curspace -= number;
      else
            dquot->dq_dqb.dqb_curspace = 0;
      if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
            dquot->dq_dqb.dqb_btime = (time_t) 0;
      clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}

static int warning_issued(struct dquot *dquot, const int warntype)
{
      int flag = (warntype == QUOTA_NL_BHARDWARN ||
            warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
            ((warntype == QUOTA_NL_IHARDWARN ||
            warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);

      if (!flag)
            return 0;
      return test_and_set_bit(flag, &dquot->dq_flags);
}

#ifdef CONFIG_PRINT_QUOTA_WARNING
static int flag_print_warnings = 1;

static inline int need_print_warning(struct dquot *dquot)
{
      if (!flag_print_warnings)
            return 0;

      switch (dquot->dq_type) {
            case USRQUOTA:
                  return current->fsuid == dquot->dq_id;
            case GRPQUOTA:
                  return in_group_p(dquot->dq_id);
      }
      return 0;
}

/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const int warntype)
{
      char *msg = NULL;
      struct tty_struct *tty;

      if (!need_print_warning(dquot))
            return;

      mutex_lock(&tty_mutex);
      tty = get_current_tty();
      if (!tty)
            goto out_lock;
      tty_write_message(tty, dquot->dq_sb->s_id);
      if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
            tty_write_message(tty, ": warning, ");
      else
            tty_write_message(tty, ": write failed, ");
      tty_write_message(tty, quotatypes[dquot->dq_type]);
      switch (warntype) {
            case QUOTA_NL_IHARDWARN:
                  msg = " file limit reached.\r\n";
                  break;
            case QUOTA_NL_ISOFTLONGWARN:
                  msg = " file quota exceeded too long.\r\n";
                  break;
            case QUOTA_NL_ISOFTWARN:
                  msg = " file quota exceeded.\r\n";
                  break;
            case QUOTA_NL_BHARDWARN:
                  msg = " block limit reached.\r\n";
                  break;
            case QUOTA_NL_BSOFTLONGWARN:
                  msg = " block quota exceeded too long.\r\n";
                  break;
            case QUOTA_NL_BSOFTWARN:
                  msg = " block quota exceeded.\r\n";
                  break;
      }
      tty_write_message(tty, msg);
out_lock:
      mutex_unlock(&tty_mutex);
}
#endif

#ifdef CONFIG_QUOTA_NETLINK_INTERFACE

/* Netlink family structure for quota */
static struct genl_family quota_genl_family = {
      .id = GENL_ID_GENERATE,
      .hdrsize = 0,
      .name = "VFS_DQUOT",
      .version = 1,
      .maxattr = QUOTA_NL_A_MAX,
};

/* Send warning to userspace about user which exceeded quota */
static void send_warning(const struct dquot *dquot, const char warntype)
{
      static atomic_t seq;
      struct sk_buff *skb;
      void *msg_head;
      int ret;
      int msg_size = 4 * nla_total_size(sizeof(u32)) +
                   2 * nla_total_size(sizeof(u64));

      /* We have to allocate using GFP_NOFS as we are called from a
       * filesystem performing write and thus further recursion into
       * the fs to free some data could cause deadlocks. */
      skb = genlmsg_new(msg_size, GFP_NOFS);
      if (!skb) {
            printk(KERN_ERR
              "VFS: Not enough memory to send quota warning.\n");
            return;
      }
      msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
                  &quota_genl_family, 0, QUOTA_NL_C_WARNING);
      if (!msg_head) {
            printk(KERN_ERR
              "VFS: Cannot store netlink header in quota warning.\n");
            goto err_out;
      }
      ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, dquot->dq_type);
      if (ret)
            goto attr_err_out;
      ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_id);
      if (ret)
            goto attr_err_out;
      ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
      if (ret)
            goto attr_err_out;
      ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR,
            MAJOR(dquot->dq_sb->s_dev));
      if (ret)
            goto attr_err_out;
      ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,
            MINOR(dquot->dq_sb->s_dev));
      if (ret)
            goto attr_err_out;
      ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current->user->uid);
      if (ret)
            goto attr_err_out;
      genlmsg_end(skb, msg_head);

      ret = genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
      if (ret < 0 && ret != -ESRCH)
            printk(KERN_ERR
                  "VFS: Failed to send notification message: %d\n", ret);
      return;
attr_err_out:
      printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
err_out:
      kfree_skb(skb);
}
#endif

static inline void flush_warnings(struct dquot * const *dquots, char *warntype)
{
      int i;

      for (i = 0; i < MAXQUOTAS; i++)
            if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN &&
                !warning_issued(dquots[i], warntype[i])) {
#ifdef CONFIG_PRINT_QUOTA_WARNING
                  print_warning(dquots[i], warntype[i]);
#endif
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
                  send_warning(dquots[i], warntype[i]);
#endif
            }
}

static inline char ignore_hardlimit(struct dquot *dquot)
{
      struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];

      return capable(CAP_SYS_RESOURCE) &&
          (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
}

/* needs dq_data_lock */
static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
      *warntype = QUOTA_NL_NOWARN;
      if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
            return QUOTA_OK;

      if (dquot->dq_dqb.dqb_ihardlimit &&
         (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
            !ignore_hardlimit(dquot)) {
            *warntype = QUOTA_NL_IHARDWARN;
            return NO_QUOTA;
      }

      if (dquot->dq_dqb.dqb_isoftlimit &&
         (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
          dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
            !ignore_hardlimit(dquot)) {
            *warntype = QUOTA_NL_ISOFTLONGWARN;
            return NO_QUOTA;
      }

      if (dquot->dq_dqb.dqb_isoftlimit &&
         (dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
          dquot->dq_dqb.dqb_itime == 0) {
            *warntype = QUOTA_NL_ISOFTWARN;
            dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
      }

      return QUOTA_OK;
}

/* needs dq_data_lock */
static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
{
      *warntype = QUOTA_NL_NOWARN;
      if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
            return QUOTA_OK;

      if (dquot->dq_dqb.dqb_bhardlimit &&
         toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
            !ignore_hardlimit(dquot)) {
            if (!prealloc)
                  *warntype = QUOTA_NL_BHARDWARN;
            return NO_QUOTA;
      }

      if (dquot->dq_dqb.dqb_bsoftlimit &&
         toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
          dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
            !ignore_hardlimit(dquot)) {
            if (!prealloc)
                  *warntype = QUOTA_NL_BSOFTLONGWARN;
            return NO_QUOTA;
      }

      if (dquot->dq_dqb.dqb_bsoftlimit &&
         toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
          dquot->dq_dqb.dqb_btime == 0) {
            if (!prealloc) {
                  *warntype = QUOTA_NL_BSOFTWARN;
                  dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
            }
            else
                  /*
                   * We don't allow preallocation to exceed softlimit so exceeding will
                   * be always printed
                   */
                  return NO_QUOTA;
      }

      return QUOTA_OK;
}

/*
 *    Initialize quota pointers in inode
 *    Transaction must be started at entry
 */
int dquot_initialize(struct inode *inode, int type)
{
      unsigned int id = 0;
      int cnt, ret = 0;

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode))
            return 0;
      down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      /* Having dqptr_sem we know NOQUOTA flags can't be altered... */
      if (IS_NOQUOTA(inode))
            goto out_err;
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (type != -1 && cnt != type)
                  continue;
            if (inode->i_dquot[cnt] == NODQUOT) {
                  switch (cnt) {
                        case USRQUOTA:
                              id = inode->i_uid;
                              break;
                        case GRPQUOTA:
                              id = inode->i_gid;
                              break;
                  }
                  inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
            }
      }
out_err:
      up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return ret;
}

/*
 *    Release all quotas referenced by inode
 *    Transaction must be started at an entry
 */
int dquot_drop(struct inode *inode)
{
      int cnt;

      down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] != NODQUOT) {
                  dqput(inode->i_dquot[cnt]);
                  inode->i_dquot[cnt] = NODQUOT;
            }
      }
      up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return 0;
}

/*
 * Following four functions update i_blocks+i_bytes fields and
 * quota information (together with appropriate checks)
 * NOTE: We absolutely rely on the fact that caller dirties
 * the inode (usually macros in quotaops.h care about this) and
 * holds a handle for the current transaction so that dquot write and
 * inode write go into the same transaction.
 */

/*
 * This operation can block, but only after everything is updated
 */
int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
{
      int cnt, ret = NO_QUOTA;
      char warntype[MAXQUOTAS];

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode)) {
out_add:
            inode_add_bytes(inode, number);
            return QUOTA_OK;
      }
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            warntype[cnt] = QUOTA_NL_NOWARN;

      down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      if (IS_NOQUOTA(inode)) {      /* Now we can do reliable test... */
            up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
            goto out_add;
      }
      spin_lock(&dq_data_lock);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
                  goto warn_put_all;
      }
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            dquot_incr_space(inode->i_dquot[cnt], number);
      }
      inode_add_bytes(inode, number);
      ret = QUOTA_OK;
warn_put_all:
      spin_unlock(&dq_data_lock);
      if (ret == QUOTA_OK)
            /* Dirtify all the dquots - this can block when journalling */
            for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                  if (inode->i_dquot[cnt])
                        mark_dquot_dirty(inode->i_dquot[cnt]);
      flush_warnings(inode->i_dquot, warntype);
      up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return ret;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_alloc_inode(const struct inode *inode, unsigned long number)
{
      int cnt, ret = NO_QUOTA;
      char warntype[MAXQUOTAS];

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode))
            return QUOTA_OK;
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            warntype[cnt] = QUOTA_NL_NOWARN;
      down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      if (IS_NOQUOTA(inode)) {
            up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
            return QUOTA_OK;
      }
      spin_lock(&dq_data_lock);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
                  goto warn_put_all;
      }

      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            dquot_incr_inodes(inode->i_dquot[cnt], number);
      }
      ret = QUOTA_OK;
warn_put_all:
      spin_unlock(&dq_data_lock);
      if (ret == QUOTA_OK)
            /* Dirtify all the dquots - this can block when journalling */
            for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                  if (inode->i_dquot[cnt])
                        mark_dquot_dirty(inode->i_dquot[cnt]);
      flush_warnings(inode->i_dquot, warntype);
      up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return ret;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_free_space(struct inode *inode, qsize_t number)
{
      unsigned int cnt;

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode)) {
out_sub:
            inode_sub_bytes(inode, number);
            return QUOTA_OK;
      }
      down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      /* Now recheck reliably when holding dqptr_sem */
      if (IS_NOQUOTA(inode)) {
            up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
            goto out_sub;
      }
      spin_lock(&dq_data_lock);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            dquot_decr_space(inode->i_dquot[cnt], number);
      }
      inode_sub_bytes(inode, number);
      spin_unlock(&dq_data_lock);
      /* Dirtify all the dquots - this can block when journalling */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            if (inode->i_dquot[cnt])
                  mark_dquot_dirty(inode->i_dquot[cnt]);
      up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return QUOTA_OK;
}

/*
 * This operation can block, but only after everything is updated
 */
int dquot_free_inode(const struct inode *inode, unsigned long number)
{
      unsigned int cnt;

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode))
            return QUOTA_OK;
      down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      /* Now recheck reliably when holding dqptr_sem */
      if (IS_NOQUOTA(inode)) {
            up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
            return QUOTA_OK;
      }
      spin_lock(&dq_data_lock);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (inode->i_dquot[cnt] == NODQUOT)
                  continue;
            dquot_decr_inodes(inode->i_dquot[cnt], number);
      }
      spin_unlock(&dq_data_lock);
      /* Dirtify all the dquots - this can block when journalling */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            if (inode->i_dquot[cnt])
                  mark_dquot_dirty(inode->i_dquot[cnt]);
      up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return QUOTA_OK;
}

/*
 * Transfer the number of inode and blocks from one diskquota to an other.
 *
 * This operation can block, but only after everything is updated
 * A transaction must be started when entering this function.
 */
int dquot_transfer(struct inode *inode, struct iattr *iattr)
{
      qsize_t space;
      struct dquot *transfer_from[MAXQUOTAS];
      struct dquot *transfer_to[MAXQUOTAS];
      int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
          chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
      char warntype[MAXQUOTAS];

      /* First test before acquiring mutex - solves deadlocks when we
         * re-enter the quota code and are already holding the mutex */
      if (IS_NOQUOTA(inode))
            return QUOTA_OK;
      /* Clear the arrays */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
            warntype[cnt] = QUOTA_NL_NOWARN;
      }
      down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      /* Now recheck reliably when holding dqptr_sem */
      if (IS_NOQUOTA(inode)) {      /* File without quota accounting? */
            up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
            return QUOTA_OK;
      }
      /* First build the transfer_to list - here we can block on
       * reading/instantiating of dquots.  We know that the transaction for
       * us was already started so we don't violate lock ranking here */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            switch (cnt) {
                  case USRQUOTA:
                        if (!chuid)
                              continue;
                        transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
                        break;
                  case GRPQUOTA:
                        if (!chgid)
                              continue;
                        transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
                        break;
            }
      }
      spin_lock(&dq_data_lock);
      space = inode_get_bytes(inode);
      /* Build the transfer_from list and check the limits */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (transfer_to[cnt] == NODQUOT)
                  continue;
            transfer_from[cnt] = inode->i_dquot[cnt];
            if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
                check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
                  goto warn_put_all;
      }

      /*
       * Finally perform the needed transfer from transfer_from to transfer_to
       */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            /*
             * Skip changes for same uid or gid or for turned off quota-type.
             */
            if (transfer_to[cnt] == NODQUOT)
                  continue;

            /* Due to IO error we might not have transfer_from[] structure */
            if (transfer_from[cnt]) {
                  dquot_decr_inodes(transfer_from[cnt], 1);
                  dquot_decr_space(transfer_from[cnt], space);
            }

            dquot_incr_inodes(transfer_to[cnt], 1);
            dquot_incr_space(transfer_to[cnt], space);

            inode->i_dquot[cnt] = transfer_to[cnt];
      }
      ret = QUOTA_OK;
warn_put_all:
      spin_unlock(&dq_data_lock);
      /* Dirtify all the dquots - this can block when journalling */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (transfer_from[cnt])
                  mark_dquot_dirty(transfer_from[cnt]);
            if (transfer_to[cnt])
                  mark_dquot_dirty(transfer_to[cnt]);
      }
      flush_warnings(transfer_to, warntype);
      
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
                  dqput(transfer_from[cnt]);
            if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
                  dqput(transfer_to[cnt]);
      }
      up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
      return ret;
}

/*
 * Write info of quota file to disk
 */
int dquot_commit_info(struct super_block *sb, int type)
{
      int ret;
      struct quota_info *dqopt = sb_dqopt(sb);

      mutex_lock(&dqopt->dqio_mutex);
      ret = dqopt->ops[type]->write_file_info(sb, type);
      mutex_unlock(&dqopt->dqio_mutex);
      return ret;
}

/*
 * Definitions of diskquota operations.
 */
struct dquot_operations dquot_operations = {
      .initialize = dquot_initialize,
      .drop       = dquot_drop,
      .alloc_space      = dquot_alloc_space,
      .alloc_inode      = dquot_alloc_inode,
      .free_space = dquot_free_space,
      .free_inode = dquot_free_inode,
      .transfer   = dquot_transfer,
      .write_dquot      = dquot_commit,
      .acquire_dquot    = dquot_acquire,
      .release_dquot    = dquot_release,
      .mark_dirty = dquot_mark_dquot_dirty,
      .write_info = dquot_commit_info
};

static inline void set_enable_flags(struct quota_info *dqopt, int type)
{
      switch (type) {
            case USRQUOTA:
                  dqopt->flags |= DQUOT_USR_ENABLED;
                  break;
            case GRPQUOTA:
                  dqopt->flags |= DQUOT_GRP_ENABLED;
                  break;
      }
}

static inline void reset_enable_flags(struct quota_info *dqopt, int type)
{
      switch (type) {
            case USRQUOTA:
                  dqopt->flags &= ~DQUOT_USR_ENABLED;
                  break;
            case GRPQUOTA:
                  dqopt->flags &= ~DQUOT_GRP_ENABLED;
                  break;
      }
}

/*
 * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
 */
int vfs_quota_off(struct super_block *sb, int type)
{
      int cnt;
      struct quota_info *dqopt = sb_dqopt(sb);
      struct inode *toputinode[MAXQUOTAS];

      /* We need to serialize quota_off() for device */
      mutex_lock(&dqopt->dqonoff_mutex);
      for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
            toputinode[cnt] = NULL;
            if (type != -1 && cnt != type)
                  continue;
            if (!sb_has_quota_enabled(sb, cnt))
                  continue;
            reset_enable_flags(dqopt, cnt);

            /* Note: these are blocking operations */
            drop_dquot_ref(sb, cnt);
            invalidate_dquots(sb, cnt);
            /*
             * Now all dquots should be invalidated, all writes done so we should be only
             * users of the info. No locks needed.
             */
            if (info_dirty(&dqopt->info[cnt]))
                  sb->dq_op->write_info(sb, cnt);
            if (dqopt->ops[cnt]->free_file_info)
                  dqopt->ops[cnt]->free_file_info(sb, cnt);
            put_quota_format(dqopt->info[cnt].dqi_format);

            toputinode[cnt] = dqopt->files[cnt];
            dqopt->files[cnt] = NULL;
            dqopt->info[cnt].dqi_flags = 0;
            dqopt->info[cnt].dqi_igrace = 0;
            dqopt->info[cnt].dqi_bgrace = 0;
            dqopt->ops[cnt] = NULL;
      }
      mutex_unlock(&dqopt->dqonoff_mutex);
      /* Sync the superblock so that buffers with quota data are written to
       * disk (and so userspace sees correct data afterwards). */
      if (sb->s_op->sync_fs)
            sb->s_op->sync_fs(sb, 1);
      sync_blockdev(sb->s_bdev);
      /* Now the quota files are just ordinary files and we can set the
       * inode flags back. Moreover we discard the pagecache so that
       * userspace sees the writes we did bypassing the pagecache. We
       * must also discard the blockdev buffers so that we see the
       * changes done by userspace on the next quotaon() */
      for (cnt = 0; cnt < MAXQUOTAS; cnt++)
            if (toputinode[cnt]) {
                  mutex_lock(&dqopt->dqonoff_mutex);
                  /* If quota was reenabled in the meantime, we have
                   * nothing to do */
                  if (!sb_has_quota_enabled(sb, cnt)) {
                        mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
                        toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
                          S_NOATIME | S_NOQUOTA);
                        truncate_inode_pages(&toputinode[cnt]->i_data, 0);
                        mutex_unlock(&toputinode[cnt]->i_mutex);
                        mark_inode_dirty(toputinode[cnt]);
                        iput(toputinode[cnt]);
                  }
                  mutex_unlock(&dqopt->dqonoff_mutex);
            }
      if (sb->s_bdev)
            invalidate_bdev(sb->s_bdev);
      return 0;
}

/*
 *    Turn quotas on on a device
 */

/* Helper function when we already have the inode */
static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
{
      struct quota_format_type *fmt = find_quota_format(format_id);
      struct super_block *sb = inode->i_sb;
      struct quota_info *dqopt = sb_dqopt(sb);
      int error;
      int oldflags = -1;

      if (!fmt)
            return -ESRCH;
      if (!S_ISREG(inode->i_mode)) {
            error = -EACCES;
            goto out_fmt;
      }
      if (IS_RDONLY(inode)) {
            error = -EROFS;
            goto out_fmt;
      }
      if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
            error = -EINVAL;
            goto out_fmt;
      }

      /* As we bypass the pagecache we must now flush the inode so that
       * we see all the changes from userspace... */
      write_inode_now(inode, 1);
      /* And now flush the block cache so that kernel sees the changes */
      invalidate_bdev(sb->s_bdev);
      mutex_lock(&inode->i_mutex);
      mutex_lock(&dqopt->dqonoff_mutex);
      if (sb_has_quota_enabled(sb, type)) {
            error = -EBUSY;
            goto out_lock;
      }
      /* We don't want quota and atime on quota files (deadlocks possible)
       * Also nobody should write to the file - we use special IO operations
       * which ignore the immutable bit. */
      down_write(&dqopt->dqptr_sem);
      oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
      inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
      up_write(&dqopt->dqptr_sem);
      sb->dq_op->drop(inode);

      error = -EIO;
      dqopt->files[type] = igrab(inode);
      if (!dqopt->files[type])
            goto out_lock;
      error = -EINVAL;
      if (!fmt->qf_ops->check_quota_file(sb, type))
            goto out_file_init;

      dqopt->ops[type] = fmt->qf_ops;
      dqopt->info[type].dqi_format = fmt;
      INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
      mutex_lock(&dqopt->dqio_mutex);
      if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
            mutex_unlock(&dqopt->dqio_mutex);
            goto out_file_init;
      }
      mutex_unlock(&dqopt->dqio_mutex);
      mutex_unlock(&inode->i_mutex);
      set_enable_flags(dqopt, type);

      add_dquot_ref(sb, type);
      mutex_unlock(&dqopt->dqonoff_mutex);

      return 0;

out_file_init:
      dqopt->files[type] = NULL;
      iput(inode);
out_lock:
      mutex_unlock(&dqopt->dqonoff_mutex);
      if (oldflags != -1) {
            down_write(&dqopt->dqptr_sem);
            /* Set the flags back (in the case of accidental quotaon()
             * on a wrong file we don't want to mess up the flags) */
            inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
            inode->i_flags |= oldflags;
            up_write(&dqopt->dqptr_sem);
      }
      mutex_unlock(&inode->i_mutex);
out_fmt:
      put_quota_format(fmt);

      return error; 
}

/* Actual function called from quotactl() */
int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
{
      struct nameidata nd;
      int error;

      error = path_lookup(path, LOOKUP_FOLLOW, &nd);
      if (error < 0)
            return error;
      error = security_quota_on(nd.dentry);
      if (error)
            goto out_path;
      /* Quota file not on the same filesystem? */
      if (nd.mnt->mnt_sb != sb)
            error = -EXDEV;
      else
            error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
out_path:
      path_release(&nd);
      return error;
}

/*
 * This function is used when filesystem needs to initialize quotas
 * during mount time.
 */
int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
            int format_id, int type)
{
      struct dentry *dentry;
      int error;

      dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
      if (IS_ERR(dentry))
            return PTR_ERR(dentry);

      if (!dentry->d_inode) {
            error = -ENOENT;
            goto out;
      }

      error = security_quota_on(dentry);
      if (!error)
            error = vfs_quota_on_inode(dentry->d_inode, type, format_id);

out:
      dput(dentry);
      return error;
}

/* Generic routine for getting common part of quota structure */
static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
      struct mem_dqblk *dm = &dquot->dq_dqb;

      spin_lock(&dq_data_lock);
      di->dqb_bhardlimit = dm->dqb_bhardlimit;
      di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
      di->dqb_curspace = dm->dqb_curspace;
      di->dqb_ihardlimit = dm->dqb_ihardlimit;
      di->dqb_isoftlimit = dm->dqb_isoftlimit;
      di->dqb_curinodes = dm->dqb_curinodes;
      di->dqb_btime = dm->dqb_btime;
      di->dqb_itime = dm->dqb_itime;
      di->dqb_valid = QIF_ALL;
      spin_unlock(&dq_data_lock);
}

int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
      struct dquot *dquot;

      mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
      if (!(dquot = dqget(sb, id, type))) {
            mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
            return -ESRCH;
      }
      do_get_dqblk(dquot, di);
      dqput(dquot);
      mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
      return 0;
}

/* Generic routine for setting common part of quota structure */
static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
      struct mem_dqblk *dm = &dquot->dq_dqb;
      int check_blim = 0, check_ilim = 0;

      spin_lock(&dq_data_lock);
      if (di->dqb_valid & QIF_SPACE) {
            dm->dqb_curspace = di->dqb_curspace;
            check_blim = 1;
      }
      if (di->dqb_valid & QIF_BLIMITS) {
            dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
            dm->dqb_bhardlimit = di->dqb_bhardlimit;
            check_blim = 1;
      }
      if (di->dqb_valid & QIF_INODES) {
            dm->dqb_curinodes = di->dqb_curinodes;
            check_ilim = 1;
      }
      if (di->dqb_valid & QIF_ILIMITS) {
            dm->dqb_isoftlimit = di->dqb_isoftlimit;
            dm->dqb_ihardlimit = di->dqb_ihardlimit;
            check_ilim = 1;
      }
      if (di->dqb_valid & QIF_BTIME)
            dm->dqb_btime = di->dqb_btime;
      if (di->dqb_valid & QIF_ITIME)
            dm->dqb_itime = di->dqb_itime;

      if (check_blim) {
            if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
                  dm->dqb_btime = 0;
                  clear_bit(DQ_BLKS_B, &dquot->dq_flags);
            }
            else if (!(di->dqb_valid & QIF_BTIME))    /* Set grace only if user hasn't provided his own... */
                  dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
      }
      if (check_ilim) {
            if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
                  dm->dqb_itime = 0;
                  clear_bit(DQ_INODES_B, &dquot->dq_flags);
            }
            else if (!(di->dqb_valid & QIF_ITIME))    /* Set grace only if user hasn't provided his own... */
                  dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
      }
      if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
            clear_bit(DQ_FAKE_B, &dquot->dq_flags);
      else
            set_bit(DQ_FAKE_B, &dquot->dq_flags);
      spin_unlock(&dq_data_lock);
      mark_dquot_dirty(dquot);
}

int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
      struct dquot *dquot;

      mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
      if (!(dquot = dqget(sb, id, type))) {
            mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
            return -ESRCH;
      }
      do_set_dqblk(dquot, di);
      dqput(dquot);
      mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
      return 0;
}

/* Generic routine for getting common part of quota file information */
int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
      struct mem_dqinfo *mi;
  
      mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
      if (!sb_has_quota_enabled(sb, type)) {
            mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
            return -ESRCH;
      }
      mi = sb_dqopt(sb)->info + type;
      spin_lock(&dq_data_lock);
      ii->dqi_bgrace = mi->dqi_bgrace;
      ii->dqi_igrace = mi->dqi_igrace;
      ii->dqi_flags = mi->dqi_flags & DQF_MASK;
      ii->dqi_valid = IIF_ALL;
      spin_unlock(&dq_data_lock);
      mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
      return 0;
}

/* Generic routine for setting common part of quota file information */
int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
      struct mem_dqinfo *mi;

      mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
      if (!sb_has_quota_enabled(sb, type)) {
            mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
            return -ESRCH;
      }
      mi = sb_dqopt(sb)->info + type;
      spin_lock(&dq_data_lock);
      if (ii->dqi_valid & IIF_BGRACE)
            mi->dqi_bgrace = ii->dqi_bgrace;
      if (ii->dqi_valid & IIF_IGRACE)
            mi->dqi_igrace = ii->dqi_igrace;
      if (ii->dqi_valid & IIF_FLAGS)
            mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
      spin_unlock(&dq_data_lock);
      mark_info_dirty(sb, type);
      /* Force write to disk */
      sb->dq_op->write_info(sb, type);
      mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
      return 0;
}

struct quotactl_ops vfs_quotactl_ops = {
      .quota_on   = vfs_quota_on,
      .quota_off  = vfs_quota_off,
      .quota_sync = vfs_quota_sync,
      .get_info   = vfs_get_dqinfo,
      .set_info   = vfs_set_dqinfo,
      .get_dqblk  = vfs_get_dqblk,
      .set_dqblk  = vfs_set_dqblk
};

static ctl_table fs_dqstats_table[] = {
      {
            .ctl_name   = FS_DQ_LOOKUPS,
            .procname   = "lookups",
            .data       = &dqstats.lookups,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_DROPS,
            .procname   = "drops",
            .data       = &dqstats.drops,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_READS,
            .procname   = "reads",
            .data       = &dqstats.reads,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_WRITES,
            .procname   = "writes",
            .data       = &dqstats.writes,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_CACHE_HITS,
            .procname   = "cache_hits",
            .data       = &dqstats.cache_hits,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_ALLOCATED,
            .procname   = "allocated_dquots",
            .data       = &dqstats.allocated_dquots,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_FREE,
            .procname   = "free_dquots",
            .data       = &dqstats.free_dquots,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
      {
            .ctl_name   = FS_DQ_SYNCS,
            .procname   = "syncs",
            .data       = &dqstats.syncs,
            .maxlen           = sizeof(int),
            .mode       = 0444,
            .proc_handler     = &proc_dointvec,
      },
#ifdef CONFIG_PRINT_QUOTA_WARNING
      {
            .ctl_name   = FS_DQ_WARNINGS,
            .procname   = "warnings",
            .data       = &flag_print_warnings,
            .maxlen           = sizeof(int),
            .mode       = 0644,
            .proc_handler     = &proc_dointvec,
      },
#endif
      { .ctl_name = 0 },
};

static ctl_table fs_table[] = {
      {
            .ctl_name   = FS_DQSTATS,
            .procname   = "quota",
            .mode       = 0555,
            .child            = fs_dqstats_table,
      },
      { .ctl_name = 0 },
};

static ctl_table sys_table[] = {
      {
            .ctl_name   = CTL_FS,
            .procname   = "fs",
            .mode       = 0555,
            .child            = fs_table,
      },
      { .ctl_name = 0 },
};

static int __init dquot_init(void)
{
      int i;
      unsigned long nr_hash, order;

      printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);

      register_sysctl_table(sys_table);

      dquot_cachep = kmem_cache_create("dquot",
                  sizeof(struct dquot), sizeof(unsigned long) * 4,
                  (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
                        SLAB_MEM_SPREAD|SLAB_PANIC),
                  NULL);

      order = 0;
      dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
      if (!dquot_hash)
            panic("Cannot create dquot hash table");

      /* Find power-of-two hlist_heads which can fit into allocation */
      nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
      dq_hash_bits = 0;
      do {
            dq_hash_bits++;
      } while (nr_hash >> dq_hash_bits);
      dq_hash_bits--;

      nr_hash = 1UL << dq_hash_bits;
      dq_hash_mask = nr_hash - 1;
      for (i = 0; i < nr_hash; i++)
            INIT_HLIST_HEAD(dquot_hash + i);

      printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
                  nr_hash, order, (PAGE_SIZE << order));

      register_shrinker(&dqcache_shrinker);

#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
      if (genl_register_family(&quota_genl_family) != 0)
            printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
#endif

      return 0;
}
module_init(dquot_init);

EXPORT_SYMBOL(register_quota_format);
EXPORT_SYMBOL(unregister_quota_format);
EXPORT_SYMBOL(dqstats);
EXPORT_SYMBOL(dq_data_lock);
EXPORT_SYMBOL(vfs_quota_on);
EXPORT_SYMBOL(vfs_quota_on_mount);
EXPORT_SYMBOL(vfs_quota_off);
EXPORT_SYMBOL(vfs_quota_sync);
EXPORT_SYMBOL(vfs_get_dqinfo);
EXPORT_SYMBOL(vfs_set_dqinfo);
EXPORT_SYMBOL(vfs_get_dqblk);
EXPORT_SYMBOL(vfs_set_dqblk);
EXPORT_SYMBOL(dquot_commit);
EXPORT_SYMBOL(dquot_commit_info);
EXPORT_SYMBOL(dquot_acquire);
EXPORT_SYMBOL(dquot_release);
EXPORT_SYMBOL(dquot_mark_dquot_dirty);
EXPORT_SYMBOL(dquot_initialize);
EXPORT_SYMBOL(dquot_drop);
EXPORT_SYMBOL(dquot_alloc_space);
EXPORT_SYMBOL(dquot_alloc_inode);
EXPORT_SYMBOL(dquot_free_space);
EXPORT_SYMBOL(dquot_free_inode);
EXPORT_SYMBOL(dquot_transfer);

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