/*
   * 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.
   * 

   * 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/capability.h>

  #include <linux/quotaops.h>

  #include "../internal.h" /* ugh */

  
  #include <asm/uaccess.h>

  /*

   * There are three quota SMP locks. dq_list_lock protects all lists with quotas

   * and quota formats.

   * 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(). dq_state_lock protects
   * modifications of quota state (on quotaon and quotaoff) and readers who care
   * about latest values take it as well.

   *

   * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
   *   dq_list_lock > dq_state_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.
   * Special care needs to be taken about S_NOQUOTA inode flag (marking that
   * inode is a quota file). Functions adding pointers from inode to dquots have
   * to check this flag under dqptr_sem and then (if S_NOQUOTA is not set) they
   * have to do all pointer modifications before dropping dqptr_sem. This makes
   * sure they cannot race with quotaon which first sets S_NOQUOTA flag and
   * then drops all pointers to dquots from an inode.

   *

   * 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

   * The lock ordering of dqptr_sem imposed by quota code is only dqonoff_sem >
   * dqptr_sem. But filesystem has to count with the fact that functions such as
   * dquot_alloc_space() acquire dqptr_sem and they usually have to be called
   * from inside a transaction to keep filesystem consistency after a crash. Also
   * filesystems usually want to do some IO on dquot from ->mark_dirty which is
   * called with dqptr_sem held.

   * i_mutex on quota files is special (it's below dqio_mutex)

   */

  static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
  static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
  __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);

  EXPORT_SYMBOL(dq_data_lock);

  void __quota_error(struct super_block *sb, const char *func,

  		   const char *fmt, ...)

  {

  	if (printk_ratelimit()) {

  		va_list args;
  		struct va_format vaf;

  		va_start(args, fmt);

  
  		vaf.fmt = fmt;
  		vaf.va = &args;
  
  		printk(KERN_ERR "Quota error (device %s): %s: %pV
  ",
  		       sb->s_id, func, &vaf);

  		va_end(args);
  	}
  }
  EXPORT_SYMBOL(__quota_error);

  #if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)

  static char *quotatypes[] = INITQFNAMES;

  #endif

  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;
  }

  EXPORT_SYMBOL(register_quota_format);

  
  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);
  }

  EXPORT_SYMBOL(unregister_quota_format);

  
  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;

  EXPORT_SYMBOL(dqstats);

  static qsize_t inode_get_rsv_space(struct inode *inode);

  static void __dquot_initialize(struct inode *inode, int type);

  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;
  	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 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 NULL;

  }
  
  /* 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_inc(DQST_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_dec(DQST_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_inc(DQST_ALLOC_DQUOTS);

  }
  
  static inline void remove_inuse(struct dquot *dquot)
  {

  	dqstats_dec(DQST_ALLOC_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);

  }

  static inline int dquot_dirty(struct dquot *dquot)
  {
  	return test_bit(DQ_MOD_B, &dquot->dq_flags);
  }
  
  static inline int mark_dquot_dirty(struct dquot *dquot)
  {
  	return dquot->dq_sb->dq_op->mark_dirty(dquot);
  }

  /* Mark dquot dirty in atomic manner, and return it's old dirty flag state */

  int dquot_mark_dquot_dirty(struct dquot *dquot)
  {

  	int ret = 1;
  
  	/* If quota is dirty already, we don't have to acquire dq_list_lock */
  	if (test_bit(DQ_MOD_B, &dquot->dq_flags))
  		return 1;

  	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);

  		ret = 0;
  	}

  	spin_unlock(&dq_list_lock);

  	return ret;

  }

  EXPORT_SYMBOL(dquot_mark_dquot_dirty);

  /* Dirtify all the dquots - this can block when journalling */
  static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
  {
  	int ret, err, cnt;
  
  	ret = err = 0;
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (dquot[cnt])
  			/* Even in case of error we have to continue */
  			ret = mark_dquot_dirty(dquot[cnt]);
  		if (!err)
  			err = ret;
  	}
  	return err;
  }
  
  static inline void dqput_all(struct dquot **dquot)
  {
  	unsigned int cnt;
  
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		dqput(dquot[cnt]);
  }

  /* 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;
  }

  EXPORT_SYMBOL(dquot_acquire);

  
  /*
   *	Write dquot to disk
   */
  int dquot_commit(struct dquot *dquot)
  {

  	int ret = 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);

  	else
  		ret = -EIO;

  out_sem:

  	mutex_unlock(&dqopt->dqio_mutex);

  	return ret;
  }

  EXPORT_SYMBOL(dquot_commit);

  
  /*
   *	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;
  }

  EXPORT_SYMBOL(dquot_release);

  void dquot_destroy(struct dquot *dquot)

  {
  	kmem_cache_free(dquot_cachep, dquot);
  }

  EXPORT_SYMBOL(dquot_destroy);

  
  static inline void do_destroy_dquot(struct dquot *dquot)
  {
  	dquot->dq_sb->dq_op->destroy_dquot(dquot);
  }

  /* 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) or parallel quotactl call. 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);

  		do_destroy_dquot(dquot);

  	}
  	spin_unlock(&dq_list_lock);
  }

  /* Call callback for every active dquot on given filesystem */
  int dquot_scan_active(struct super_block *sb,
  		      int (*fn)(struct dquot *dquot, unsigned long priv),
  		      unsigned long priv)
  {
  	struct dquot *dquot, *old_dquot = NULL;
  	int ret = 0;
  
  	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  	spin_lock(&dq_list_lock);
  	list_for_each_entry(dquot, &inuse_list, dq_inuse) {
  		if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
  			continue;
  		if (dquot->dq_sb != sb)
  			continue;
  		/* Now we have active dquot so we can just increase use count */
  		atomic_inc(&dquot->dq_count);

  		spin_unlock(&dq_list_lock);

  		dqstats_inc(DQST_LOOKUPS);

  		dqput(old_dquot);
  		old_dquot = dquot;
  		ret = fn(dquot, priv);
  		if (ret < 0)
  			goto out;
  		spin_lock(&dq_list_lock);
  		/* We are safe to continue now because our dquot could not
  		 * be moved out of the inuse list while we hold the reference */
  	}
  	spin_unlock(&dq_list_lock);
  out:
  	dqput(old_dquot);
  	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
  	return ret;
  }

  EXPORT_SYMBOL(dquot_scan_active);

  int dquot_quota_sync(struct super_block *sb, int type, int wait)

  {
  	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_active(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);

  			spin_unlock(&dq_list_lock);

  			dqstats_inc(DQST_LOOKUPS);

  			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_active(sb, cnt)
  		    && info_dirty(&dqopt->info[cnt]))

  			sb->dq_op->write_info(sb, cnt);

  	dqstats_inc(DQST_SYNCS);

  	mutex_unlock(&dqopt->dqonoff_mutex);

  	if (!wait || (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE))
  		return 0;
  
  	/* This is not very clever (and fast) but currently I don't know about
  	 * any other simple way of getting quota data to disk and we must get
  	 * them there for userspace to be visible... */
  	if (sb->s_op->sync_fs)
  		sb->s_op->sync_fs(sb, 1);
  	sync_blockdev(sb->s_bdev);
  
  	/*
  	 * Now when everything is written we can discard the pagecache so
  	 * that userspace sees the changes.
  	 */
  	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (type != -1 && cnt != type)
  			continue;
  		if (!sb_has_quota_active(sb, cnt))
  			continue;
  		mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
  				  I_MUTEX_QUOTA);
  		truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
  		mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
  	}
  	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);

  	return 0;
  }

  EXPORT_SYMBOL(dquot_quota_sync);

  
  /* 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);

  		do_destroy_dquot(dquot);

  		count--;
  		head = free_dquots.prev;
  	}
  }
  
  /*
   * This is called from kswapd when we think we need some
   * more memory
   */

  static int shrink_dqcache_memory(struct shrinker *shrink,
  				 struct shrink_control *sc)

  {

  	int nr = sc->nr_to_scan;

  	if (nr) {
  		spin_lock(&dq_list_lock);
  		prune_dqcache(nr);
  		spin_unlock(&dq_list_lock);
  	}

  	return ((unsigned)
  		percpu_counter_read_positive(&dqstats.counter[DQST_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...

   */

  void dqput(struct dquot *dquot)

  {

  	int ret;

  	if (!dquot)
  		return;

  #ifdef CONFIG_QUOTA_DEBUG

  	if (!atomic_read(&dquot->dq_count)) {

  		quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
  			    quotatypes[dquot->dq_type], dquot->dq_id);

  		BUG();
  	}
  #endif

  	dqstats_inc(DQST_DROPS);

  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_active(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 */

  		ret = dquot->dq_sb->dq_op->write_dquot(dquot);
  		if (ret < 0) {

  			quota_error(dquot->dq_sb, "Can't write quota structure"
  				    " (error %d). Quota may get out of sync!",
  				    ret);

  			/*
  			 * We clear dirty bit anyway, so that we avoid
  			 * infinite loop here
  			 */
  			spin_lock(&dq_list_lock);
  			clear_dquot_dirty(dquot);
  			spin_unlock(&dq_list_lock);
  		}

  		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 CONFIG_QUOTA_DEBUG

  	/* sanity check */

  	BUG_ON(!list_empty(&dquot->dq_free));

  #endif
  	put_dquot_last(dquot);
  	spin_unlock(&dq_list_lock);
  }

  EXPORT_SYMBOL(dqput);

  struct dquot *dquot_alloc(struct super_block *sb, int type)

  {
  	return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
  }

  EXPORT_SYMBOL(dquot_alloc);

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

  	dquot = sb->dq_op->alloc_dquot(sb, type);

  	if(!dquot)

  		return NULL;

  	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

   *
   * Locking is slightly tricky here. We are guarded from parallel quotaoff()
   * destroying our dquot by:
   *   a) checking for quota flags under dq_list_lock and
   *   b) getting a reference to dquot before we release dq_list_lock

   */

  struct dquot *dqget(struct super_block *sb, unsigned int id, int type)

  {
  	unsigned int hashent = hashfn(sb, id, type);

  	struct dquot *dquot = NULL, *empty = NULL;

          if (!sb_has_quota_active(sb, type))

  		return NULL;

  we_slept:
  	spin_lock(&dq_list_lock);

  	spin_lock(&dq_state_lock);
  	if (!sb_has_quota_active(sb, type)) {
  		spin_unlock(&dq_state_lock);
  		spin_unlock(&dq_list_lock);
  		goto out;
  	}
  	spin_unlock(&dq_state_lock);

  	dquot = find_dquot(hashent, sb, id, type);
  	if (!dquot) {
  		if (!empty) {

  			spin_unlock(&dq_list_lock);

  			empty = get_empty_dquot(sb, type);
  			if (!empty)

  				schedule();	/* Try to wait for a moment... */
  			goto we_slept;
  		}
  		dquot = empty;

  		empty = NULL;

  		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);

  		spin_unlock(&dq_list_lock);

  		dqstats_inc(DQST_LOOKUPS);

  	} else {
  		if (!atomic_read(&dquot->dq_count))
  			remove_free_dquot(dquot);
  		atomic_inc(&dquot->dq_count);

  		spin_unlock(&dq_list_lock);

  		dqstats_inc(DQST_CACHE_HITS);
  		dqstats_inc(DQST_LOOKUPS);

  	}

  	/* 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 / allocate space in quota file */
  	if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) &&
  	    sb->dq_op->acquire_dquot(dquot) < 0) {

  		dqput(dquot);

  		dquot = NULL;

  		goto out;

  	}

  #ifdef CONFIG_QUOTA_DEBUG

  	BUG_ON(!dquot->dq_sb);	/* Has somebody invalidated entry under us? */

  #endif

  out:
  	if (empty)
  		do_destroy_dquot(empty);

  
  	return dquot;
  }

  EXPORT_SYMBOL(dqget);

  
  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];

  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)

  		if (!inode->i_dquot[cnt])

  			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, *old_inode = NULL;

  #ifdef CONFIG_QUOTA_DEBUG

  	int reserved = 0;

  #endif

  	spin_lock(&inode_sb_list_lock);

  	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {

  		spin_lock(&inode->i_lock);
  		if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
  		    !atomic_read(&inode->i_writecount) ||
  		    !dqinit_needed(inode, type)) {
  			spin_unlock(&inode->i_lock);

  			continue;

  		}

  #ifdef CONFIG_QUOTA_DEBUG

  		if (unlikely(inode_get_rsv_space(inode) > 0))
  			reserved = 1;

  #endif

  		__iget(inode);

  		spin_unlock(&inode->i_lock);

  		spin_unlock(&inode_sb_list_lock);

  		iput(old_inode);

  		__dquot_initialize(inode, type);

  
  		/*
  		 * We hold a reference to 'inode' so it couldn't have been
  		 * removed from s_inodes list while we dropped the
  		 * inode_sb_list_lock We cannot iput the inode now as we can be
  		 * holding the last reference and we cannot iput it under
  		 * inode_sb_list_lock. So we keep the reference and iput it
  		 * later.
  		 */

  		old_inode = inode;

  		spin_lock(&inode_sb_list_lock);

  	}

  	spin_unlock(&inode_sb_list_lock);

  	iput(old_inode);

  #ifdef CONFIG_QUOTA_DEBUG

  	if (reserved) {

  		quota_error(sb, "Writes happened before quota was turned on "
  			"thus quota information is probably inconsistent. "
  			"Please run quotacheck(8)");

  	}

  #endif

  }

  /*
   * 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 and add dquot to list for freeing

   * if we have the last reference to dquot

   * 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] = NULL;
  	if (dquot) {

  		if (dqput_blocks(dquot)) {

  #ifdef CONFIG_QUOTA_DEBUG

  			if (atomic_read(&dquot->dq_count) != 1)

  				quota_error(inode->i_sb, "Adding dquot with "
  					    "dq_count %d to dispose list",
  					    atomic_read(&dquot->dq_count));

  #endif
  			spin_lock(&dq_list_lock);

  			/* As dquot must have currently users it can't be on
  			 * the free list... */
  			list_add(&dquot->dq_free, tofree_head);

  			spin_unlock(&dq_list_lock);
  			return 1;
  		}
  		else
  			dqput(dquot);   /* We have guaranteed we won't block */
  	}
  	return 0;
  }

  /*
   * Free list of dquots
   * Dquots are removed from inodes and 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;

  	while (act_head != tofree_head) {
  		dquot = list_entry(act_head, struct dquot, dq_free);
  		act_head = act_head->next;

  		/* Remove dquot from the list so we won't have problems... */
  		list_del_init(&dquot->dq_free);

  		dqput(dquot);
  	}
  }

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

  	int reserved = 0;

  	spin_lock(&inode_sb_list_lock);

  	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {

  		/*
  		 *  We have to scan also I_NEW inodes because they can already
  		 *  have quota pointer initialized. Luckily, we need to touch
  		 *  only quota pointers and these have separate locking
  		 *  (dqptr_sem).
  		 */

  		if (!IS_NOQUOTA(inode)) {
  			if (unlikely(inode_get_rsv_space(inode) > 0))
  				reserved = 1;

  			remove_inode_dquot_ref(inode, type, tofree_head);

  		}

  	}

  	spin_unlock(&inode_sb_list_lock);

  #ifdef CONFIG_QUOTA_DEBUG
  	if (reserved) {
  		printk(KERN_WARNING "VFS (%s): Writes happened after quota"
  			" was disabled thus quota information is probably "
  			"inconsistent. Please run quotacheck(8).
  ", sb->s_id);
  	}
  #endif

  }

  /* 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, qsize_t 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_resv_space(struct dquot *dquot, qsize_t number)
  {
  	dquot->dq_dqb.dqb_rsvspace += number;
  }

  /*
   * Claim reserved quota space
   */

  static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number)

  {

  	if (dquot->dq_dqb.dqb_rsvspace < number) {
  		WARN_ON_ONCE(1);
  		number = dquot->dq_dqb.dqb_rsvspace;
  	}

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

  	if (dquot->dq_dqb.dqb_rsvspace >= number)
  		dquot->dq_dqb.dqb_rsvspace -= number;
  	else {
  		WARN_ON_ONCE(1);
  		dquot->dq_dqb.dqb_rsvspace = 0;
  	}

  }

  static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)

  {

  	if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
  	    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 void dquot_decr_space(struct dquot *dquot, qsize_t number)

  {

  	if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
  	    dquot->dq_dqb.dqb_curspace >= number)

  		dquot->dq_dqb.dqb_curspace -= number;
  	else
  		dquot->dq_dqb.dqb_curspace = 0;

  	if (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 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 (warntype == QUOTA_NL_IHARDBELOW ||
  	    warntype == QUOTA_NL_ISOFTBELOW ||
  	    warntype == QUOTA_NL_BHARDBELOW ||
  	    warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))

  		return;

  	tty = get_current_tty();
  	if (!tty)

  		return;

  	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
  ";
  			break;

  		case QUOTA_NL_ISOFTLONGWARN:

  			msg = " file quota exceeded too long.\r
  ";
  			break;

  		case QUOTA_NL_ISOFTWARN:

  			msg = " file quota exceeded.\r
  ";
  			break;

  		case QUOTA_NL_BHARDWARN:

  			msg = " block limit reached.\r
  ";
  			break;

  		case QUOTA_NL_BSOFTLONGWARN:

  			msg = " block quota exceeded too long.\r
  ";
  			break;

  		case QUOTA_NL_BSOFTWARN:

  			msg = " block quota exceeded.\r
  ";
  			break;
  	}

  	tty_write_message(tty, msg);

  	tty_kref_put(tty);

  }

  #endif

  /*
   * Write warnings to the console and send warning messages over netlink.
   *
   * Note that this function can sleep.
   */

  static void flush_warnings(struct dquot *const *dquots, char *warntype)

  {

  	struct dquot *dq;

  	int i;

  	for (i = 0; i < MAXQUOTAS; i++) {
  		dq = dquots[i];
  		if (dq && warntype[i] != QUOTA_NL_NOWARN &&
  		    !warning_issued(dq, warntype[i])) {

  #ifdef CONFIG_PRINT_QUOTA_WARNING

  			print_warning(dq, warntype[i]);

  #endif

  			quota_send_warning(dq->dq_type, dq->dq_id,
  					   dq->dq_sb->s_dev, warntype[i]);

  		}

  	}

  }

  static int 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, qsize_t inodes, char *warntype)

  {

  	qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;

  	*warntype = QUOTA_NL_NOWARN;

  	if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type) ||
  	    test_bit(DQ_FAKE_B, &dquot->dq_flags))

  		return 0;

  
  	if (dquot->dq_dqb.dqb_ihardlimit &&

  	    newinodes > dquot->dq_dqb.dqb_ihardlimit &&

              !ignore_hardlimit(dquot)) {

  		*warntype = QUOTA_NL_IHARDWARN;

  		return -EDQUOT;

  	}
  
  	if (dquot->dq_dqb.dqb_isoftlimit &&

  	    newinodes > 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 -EDQUOT;

  	}
  
  	if (dquot->dq_dqb.dqb_isoftlimit &&

  	    newinodes > 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 0;

  }
  
  /* needs dq_data_lock */
  static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
  {

  	qsize_t tspace;

  	struct super_block *sb = dquot->dq_sb;

  	*warntype = QUOTA_NL_NOWARN;

  	if (!sb_has_quota_limits_enabled(sb, dquot->dq_type) ||

  	    test_bit(DQ_FAKE_B, &dquot->dq_flags))

  		return 0;

  	tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
  		+ space;

  	if (dquot->dq_dqb.dqb_bhardlimit &&

  	    tspace > dquot->dq_dqb.dqb_bhardlimit &&

              !ignore_hardlimit(dquot)) {
  		if (!prealloc)

  			*warntype = QUOTA_NL_BHARDWARN;

  		return -EDQUOT;

  	}
  
  	if (dquot->dq_dqb.dqb_bsoftlimit &&

  	    tspace > 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 -EDQUOT;

  	}
  
  	if (dquot->dq_dqb.dqb_bsoftlimit &&

  	    tspace > 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(sb)->info[dquot->dq_type].dqi_bgrace;

  		}
  		else
  			/*
  			 * We don't allow preallocation to exceed softlimit so exceeding will
  			 * be always printed
  			 */

  			return -EDQUOT;

  	}

  	return 0;

  }

  static int info_idq_free(struct dquot *dquot, qsize_t inodes)

  {

  	qsize_t newinodes;

  	if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||

  	    dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
  	    !sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_type))

  		return QUOTA_NL_NOWARN;

  	newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
  	if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)

  		return QUOTA_NL_ISOFTBELOW;
  	if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&

  	    newinodes < dquot->dq_dqb.dqb_ihardlimit)

  		return QUOTA_NL_IHARDBELOW;
  	return QUOTA_NL_NOWARN;
  }
  
  static int info_bdq_free(struct dquot *dquot, qsize_t space)
  {
  	if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||

  	    dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit)

  		return QUOTA_NL_NOWARN;

  	if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit)

  		return QUOTA_NL_BSOFTBELOW;

  	if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit &&
  	    dquot->dq_dqb.dqb_curspace - space < dquot->dq_dqb.dqb_bhardlimit)

  		return QUOTA_NL_BHARDBELOW;
  	return QUOTA_NL_NOWARN;
  }

  static int dquot_active(const struct inode *inode)
  {
  	struct super_block *sb = inode->i_sb;
  
  	if (IS_NOQUOTA(inode))
  		return 0;
  	return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
  }

  /*

   * Initialize quota pointers in inode
   *
   * We do things in a bit complicated way but by that we avoid calling
   * dqget() and thus filesystem callbacks under dqptr_sem.
   *
   * It is better to call this function outside of any transaction as it
   * might need a lot of space in journal for dquot structure allocation.

   */

  static void __dquot_initialize(struct inode *inode, int type)

  {
  	unsigned int id = 0;

  	int cnt;

  	struct dquot *got[MAXQUOTAS];

  	struct super_block *sb = inode->i_sb;

  	qsize_t rsv;

  	/* First test before acquiring mutex - solves deadlocks when we
           * re-enter the quota code and are already holding the mutex */

  	if (!dquot_active(inode))

  		return;

  
  	/* First get references to structures we might need. */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		got[cnt] = NULL;

  		if (type != -1 && cnt != type)
  			continue;
  		switch (cnt) {
  		case USRQUOTA:
  			id = inode->i_uid;
  			break;
  		case GRPQUOTA:
  			id = inode->i_gid;
  			break;
  		}
  		got[cnt] = dqget(sb, id, cnt);
  	}
  
  	down_write(&sb_dqopt(sb)->dqptr_sem);

  	if (IS_NOQUOTA(inode))
  		goto out_err;
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (type != -1 && cnt != type)
  			continue;

  		/* Avoid races with quotaoff() */
  		if (!sb_has_quota_active(sb, cnt))
  			continue;

  		/* We could race with quotaon or dqget() could have failed */
  		if (!got[cnt])
  			continue;

  		if (!inode->i_dquot[cnt]) {

  			inode->i_dquot[cnt] = got[cnt];

  			got[cnt] = NULL;

  			/*
  			 * Make quota reservation system happy if someone
  			 * did a write before quota was turned on
  			 */
  			rsv = inode_get_rsv_space(inode);
  			if (unlikely(rsv))
  				dquot_resv_space(inode->i_dquot[cnt], rsv);

  		}
  	}
  out_err:

  	up_write(&sb_dqopt(sb)->dqptr_sem);
  	/* Drop unused references */

  	dqput_all(got);

  }
  
  void dquot_initialize(struct inode *inode)
  {
  	__dquot_initialize(inode, -1);

  }

  EXPORT_SYMBOL(dquot_initialize);

  
  /*
   * 	Release all quotas referenced by inode

   */

  static void __dquot_drop(struct inode *inode)

  {
  	int cnt;

  	struct dquot *put[MAXQUOTAS];

  	down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		put[cnt] = inode->i_dquot[cnt];

  		inode->i_dquot[cnt] = NULL;

  	}
  	up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	dqput_all(put);

  }

  void dquot_drop(struct inode *inode)
  {
  	int cnt;
  
  	if (IS_NOQUOTA(inode))
  		return;
  
  	/*
  	 * Test before calling to rule out calls from proc and such
  	 * where we are not allowed to block. Note that this is
  	 * actually reliable test even without the lock - the caller
  	 * must assure that nobody can come after the DQUOT_DROP and
  	 * add quota pointers back anyway.
  	 */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (inode->i_dquot[cnt])
  			break;
  	}
  
  	if (cnt < MAXQUOTAS)
  		__dquot_drop(inode);
  }
  EXPORT_SYMBOL(dquot_drop);

  /*

   * inode_reserved_space is managed internally by quota, and protected by
   * i_lock similar to i_blocks+i_bytes.
   */
  static qsize_t *inode_reserved_space(struct inode * inode)
  {
  	/* Filesystem must explicitly define it's own method in order to use
  	 * quota reservation interface */
  	BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
  	return inode->i_sb->dq_op->get_reserved_space(inode);
  }

  void inode_add_rsv_space(struct inode *inode, qsize_t number)

  {
  	spin_lock(&inode->i_lock);
  	*inode_reserved_space(inode) += number;
  	spin_unlock(&inode->i_lock);
  }

  EXPORT_SYMBOL(inode_add_rsv_space);

  void inode_claim_rsv_space(struct inode *inode, qsize_t number)

  {
  	spin_lock(&inode->i_lock);
  	*inode_reserved_space(inode) -= number;
  	__inode_add_bytes(inode, number);
  	spin_unlock(&inode->i_lock);
  }

  EXPORT_SYMBOL(inode_claim_rsv_space);

  void inode_sub_rsv_space(struct inode *inode, qsize_t number)

  {
  	spin_lock(&inode->i_lock);
  	*inode_reserved_space(inode) -= number;
  	spin_unlock(&inode->i_lock);
  }

  EXPORT_SYMBOL(inode_sub_rsv_space);

  
  static qsize_t inode_get_rsv_space(struct inode *inode)
  {
  	qsize_t ret;

  
  	if (!inode->i_sb->dq_op->get_reserved_space)
  		return 0;

  	spin_lock(&inode->i_lock);
  	ret = *inode_reserved_space(inode);
  	spin_unlock(&inode->i_lock);
  	return ret;
  }
  
  static void inode_incr_space(struct inode *inode, qsize_t number,
  				int reserve)
  {
  	if (reserve)
  		inode_add_rsv_space(inode, number);
  	else
  		inode_add_bytes(inode, number);
  }
  
  static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
  {
  	if (reserve)
  		inode_sub_rsv_space(inode, number);
  	else
  		inode_sub_bytes(inode, number);
  }
  
  /*

   * This functions updates 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 helpers 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 flags)

  {

  	int cnt, ret = 0;

  	char warntype[MAXQUOTAS];

  	int warn = flags & DQUOT_SPACE_WARN;
  	int reserve = flags & DQUOT_SPACE_RESERVE;

  	int nofail = flags & DQUOT_SPACE_NOFAIL;

  	/*
  	 * First test before acquiring mutex - solves deadlocks when we
  	 * re-enter the quota code and are already holding the mutex
  	 */

  	if (!dquot_active(inode)) {

  		inode_incr_space(inode, number, reserve);
  		goto out;
  	}
  
  	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)

  		warntype[cnt] = QUOTA_NL_NOWARN;

  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		ret = check_bdq(inode->i_dquot[cnt], number, !warn,
  				warntype+cnt);

  		if (ret && !nofail) {

  			spin_unlock(&dq_data_lock);
  			goto out_flush_warn;

  		}

  	}
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		if (reserve)
  			dquot_resv_space(inode->i_dquot[cnt], number);
  		else
  			dquot_incr_space(inode->i_dquot[cnt], number);

  	}

  	inode_incr_space(inode, number, reserve);

  	spin_unlock(&dq_data_lock);

  	if (reserve)
  		goto out_flush_warn;

  	mark_all_dquot_dirty(inode->i_dquot);

  out_flush_warn:
  	flush_warnings(inode->i_dquot, warntype);

  	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  out:
  	return ret;
  }

  EXPORT_SYMBOL(__dquot_alloc_space);

  
  /*
   * This operation can block, but only after everything is updated
   */

  int dquot_alloc_inode(const struct inode *inode)

  {

  	int cnt, ret = 0;

  	char warntype[MAXQUOTAS];

  	/* First test before acquiring mutex - solves deadlocks when we
           * re-enter the quota code and are already holding the mutex */

  	if (!dquot_active(inode))

  		return 0;

  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)

  		warntype[cnt] = QUOTA_NL_NOWARN;

  	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		ret = check_idq(inode->i_dquot[cnt], 1, warntype + cnt);
  		if (ret)

  			goto warn_put_all;
  	}
  
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		dquot_incr_inodes(inode->i_dquot[cnt], 1);

  	}

  warn_put_all:
  	spin_unlock(&dq_data_lock);

  	if (ret == 0)

  		mark_all_dquot_dirty(inode->i_dquot);

  	flush_warnings(inode->i_dquot, warntype);

  	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
  	return ret;
  }

  EXPORT_SYMBOL(dquot_alloc_inode);

  /*
   * Convert in-memory reserved quotas to real consumed quotas
   */
  int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)

  {
  	int cnt;

  	if (!dquot_active(inode)) {

  		inode_claim_rsv_space(inode, number);

  		return 0;

  	}
  
  	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	spin_lock(&dq_data_lock);
  	/* Claim reserved quotas to allocated quotas */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (inode->i_dquot[cnt])

  			dquot_claim_reserved_space(inode->i_dquot[cnt],
  							number);
  	}
  	/* Update inode bytes */

  	inode_claim_rsv_space(inode, number);

  	spin_unlock(&dq_data_lock);

  	mark_all_dquot_dirty(inode->i_dquot);

  	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	return 0;

  }

  EXPORT_SYMBOL(dquot_claim_space_nodirty);

  
  /*

   * This operation can block, but only after everything is updated
   */

  void __dquot_free_space(struct inode *inode, qsize_t number, int flags)

  {
  	unsigned int cnt;

  	char warntype[MAXQUOTAS];

  	int reserve = flags & DQUOT_SPACE_RESERVE;

  	/* First test before acquiring mutex - solves deadlocks when we
           * re-enter the quota code and are already holding the mutex */

  	if (!dquot_active(inode)) {

  		inode_decr_space(inode, number, reserve);

  		return;

  	}

  	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);

  		if (reserve)
  			dquot_free_reserved_space(inode->i_dquot[cnt], number);
  		else
  			dquot_decr_space(inode->i_dquot[cnt], number);

  	}

  	inode_decr_space(inode, number, reserve);

  	spin_unlock(&dq_data_lock);

  
  	if (reserve)
  		goto out_unlock;

  	mark_all_dquot_dirty(inode->i_dquot);

  out_unlock:

  	flush_warnings(inode->i_dquot, warntype);

  	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  }

  EXPORT_SYMBOL(__dquot_free_space);

  
  /*

   * This operation can block, but only after everything is updated
   */

  void dquot_free_inode(const struct inode *inode)

  {
  	unsigned int cnt;

  	char warntype[MAXQUOTAS];

  	/* First test before acquiring mutex - solves deadlocks when we
           * re-enter the quota code and are already holding the mutex */

  	if (!dquot_active(inode))

  		return;

  	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);

  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

  		if (!inode->i_dquot[cnt])

  			continue;

  		warntype[cnt] = info_idq_free(inode->i_dquot[cnt], 1);
  		dquot_decr_inodes(inode->i_dquot[cnt], 1);

  	}
  	spin_unlock(&dq_data_lock);