text: /*
   * 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/sched.h>
  #include <linux/kmod.h>
  #include <linux/namei.h>
  #include <linux/capability.h>
  #include <linux/quotaops.h>
  #include "../internal.h" /* ugh */
  
  #include <linux/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
   *
   * Operation accessing dquots via inode pointers are protected by dquot_srcu.
   * Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
   * synchronize_srcu(&dquot_srcu) is called after clearing pointers from
   * inode and before dropping dquot references to avoid use of dquots after
   * they are freed. dq_data_lock is used to serialize the pointer setting and
   * clearing operations.
   * 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 dq_data_lock and then (if S_NOQUOTA is not set) they
   * have to do all pointer modifications before dropping dq_data_lock. 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:
   *   dqonoff_mutex > i_mutex > journal_lock > dquot->dq_lock > dqio_mutex
   * dqonoff_mutex > i_mutex comes from dquot_quota_sync, dquot_enable, etc.
   */
  
  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);
  DEFINE_STATIC_SRCU(dquot_srcu);
  
  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\n",
  		       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 int __dquot_initialize(struct inode *inode, int type);
  
  static inline unsigned int
  hashfn(const struct super_block *sb, struct kqid qid)
  {
  	unsigned int id = from_kqid(&init_user_ns, qid);
  	int type = qid.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);
  	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,
  				struct kqid qid)
  {
  	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 && qid_eq(dquot->dq_id, qid))
  			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_id.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_id.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_id.type]->commit_dqblk(dquot);
  		/* Write the info if needed */
  		if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
  			ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
  					dquot->dq_sb, dquot->dq_id.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_id.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_id.type]->release_dqblk) {
  		ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
  		/* Write the info */
  		if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
  			ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
  						dquot->dq_sb, dquot->dq_id.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_id.type != type)
  			continue;
  		/* Wait for dquot users */
  		if (atomic_read(&dquot->dq_count)) {
  			DEFINE_WAIT(wait);
  
  			dqgrab(dquot);
  			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;
  		/*
  		 * ->release_dquot() can be racing with us. Our reference
  		 * protects us from new calls to it so just wait for any
  		 * outstanding call and recheck the DQ_ACTIVE_B after that.
  		 */
  		wait_on_dquot(dquot);
  		if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
  			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);
  
  /* Write all dquot structures to quota files */
  int dquot_writeback_dquots(struct super_block *sb, int type)
  {
  	struct list_head *dirty;
  	struct dquot *dquot;
  	struct quota_info *dqopt = sb_dqopt(sb);
  	int cnt;
  	int err, ret = 0;
  
  	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 */
  			dqgrab(dquot);
  			spin_unlock(&dq_list_lock);
  			dqstats_inc(DQST_LOOKUPS);
  			err = sb->dq_op->write_dquot(dquot);
  			if (!ret && err)
  				ret = err;
  			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);
  
  	return ret;
  }
  EXPORT_SYMBOL(dquot_writeback_dquots);
  
  /* Write all dquot structures to disk and make them visible from userspace */
  int dquot_quota_sync(struct super_block *sb, int type)
  {
  	struct quota_info *dqopt = sb_dqopt(sb);
  	int cnt;
  	int ret;
  
  	ret = dquot_writeback_dquots(sb, type);
  	if (ret)
  		return ret;
  	if (dqopt->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(&dqopt->dqonoff_mutex);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (type != -1 && cnt != type)
  			continue;
  		if (!sb_has_quota_active(sb, cnt))
  			continue;
  		mutex_lock(&dqopt->files[cnt]->i_mutex);
  		truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
  		mutex_unlock(&dqopt->files[cnt]->i_mutex);
  	}
  	mutex_unlock(&dqopt->dqonoff_mutex);
  
  	return 0;
  }
  EXPORT_SYMBOL(dquot_quota_sync);
  
  static unsigned long
  dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
  {
  	struct list_head *head;
  	struct dquot *dquot;
  	unsigned long freed = 0;
  
  	spin_lock(&dq_list_lock);
  	head = free_dquots.prev;
  	while (head != &free_dquots && sc->nr_to_scan) {
  		dquot = list_entry(head, struct dquot, dq_free);
  		remove_dquot_hash(dquot);
  		remove_free_dquot(dquot);
  		remove_inuse(dquot);
  		do_destroy_dquot(dquot);
  		sc->nr_to_scan--;
  		freed++;
  		head = free_dquots.prev;
  	}
  	spin_unlock(&dq_list_lock);
  	return freed;
  }
  
  static unsigned long
  dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
  {
  	return vfs_pressure_ratio(
  	percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
  }
  
  static struct shrinker dqcache_shrinker = {
  	.count_objects = dqcache_shrink_count,
  	.scan_objects = dqcache_shrink_scan,
  	.seeks = DEFAULT_SEEKS,
  };
  
  /*
   * Put reference to dquot
   */
  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_id.type],
  			    from_kqid(&init_user_ns, 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_id.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_id = make_kqid_invalid(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, struct kqid qid)
  {
  	unsigned int hashent = hashfn(sb, qid);
  	struct dquot *dquot, *empty = NULL;
  
          if (!sb_has_quota_active(sb, qid.type))
  		return ERR_PTR(-ESRCH);
  we_slept:
  	spin_lock(&dq_list_lock);
  	spin_lock(&dq_state_lock);
  	if (!sb_has_quota_active(sb, qid.type)) {
  		spin_unlock(&dq_state_lock);
  		spin_unlock(&dq_list_lock);
  		dquot = ERR_PTR(-ESRCH);
  		goto out;
  	}
  	spin_unlock(&dq_state_lock);
  
  	dquot = find_dquot(hashent, sb, qid);
  	if (!dquot) {
  		if (!empty) {
  			spin_unlock(&dq_list_lock);
  			empty = get_empty_dquot(sb, qid.type);
  			if (!empty)
  				schedule();	/* Try to wait for a moment... */
  			goto we_slept;
  		}
  		dquot = empty;
  		empty = NULL;
  		dquot->dq_id = qid;
  		/* 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)) {
  		int err;
  
  		err = sb->dq_op->acquire_dquot(dquot);
  		if (err < 0) {
  			dqput(dquot);
  			dquot = ERR_PTR(err);
  			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 inline struct dquot **i_dquot(struct inode *inode)
  {
  	return inode->i_sb->s_op->get_dquots(inode);
  }
  
  static int dqinit_needed(struct inode *inode, int type)
  {
  	struct dquot * const *dquots;
  	int cnt;
  
  	if (IS_NOQUOTA(inode))
  		return 0;
  
  	dquots = i_dquot(inode);
  	if (type != -1)
  		return !dquots[type];
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		if (!dquots[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(&sb->s_inode_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;
  		}
  		__iget(inode);
  		spin_unlock(&inode->i_lock);
  		spin_unlock(&sb->s_inode_list_lock);
  
  #ifdef CONFIG_QUOTA_DEBUG
  		if (unlikely(inode_get_rsv_space(inode) > 0))
  			reserved = 1;
  #endif
  		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
  		 * s_inode_list_lock. We cannot iput the inode now as we can be
  		 * holding the last reference and we cannot iput it under
  		 * s_inode_list_lock. So we keep the reference and iput it
  		 * later.
  		 */
  		old_inode = inode;
  		spin_lock(&sb->s_inode_list_lock);
  	}
  	spin_unlock(&sb->s_inode_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
  }
  
  /*
   * Remove references to dquots from inode and add dquot to list for freeing
   * if we have the last reference to dquot
   */
  static void remove_inode_dquot_ref(struct inode *inode, int type,
  				   struct list_head *tofree_head)
  {
  	struct dquot **dquots = i_dquot(inode);
  	struct dquot *dquot = dquots[type];
  
  	if (!dquot)
  		return;
  
  	dquots[type] = NULL;
  	if (list_empty(&dquot->dq_free)) {
  		/*
  		 * The inode still has reference to dquot so it can't be in the
  		 * free list
  		 */
  		spin_lock(&dq_list_lock);
  		list_add(&dquot->dq_free, tofree_head);
  		spin_unlock(&dq_list_lock);
  	} else {
  		/*
  		 * Dquot is already in a list to put so we won't drop the last
  		 * reference here.
  		 */
  		dqput(dquot);
  	}
  }
  
  /*
   * 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(&sb->s_inode_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
  		 *  (dq_data_lock).
  		 */
  		spin_lock(&dq_data_lock);
  		if (!IS_NOQUOTA(inode)) {
  			if (unlikely(inode_get_rsv_space(inode) > 0))
  				reserved = 1;
  			remove_inode_dquot_ref(inode, type, tofree_head);
  		}
  		spin_unlock(&dq_data_lock);
  	}
  	spin_unlock(&sb->s_inode_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).\n", 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) {
  		remove_dquot_ref(sb, type, &tofree_head);
  		synchronize_srcu(&dquot_srcu);
  		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 void dquot_reclaim_reserved_space(struct dquot *dquot, qsize_t number)
  {
  	if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
  		number = dquot->dq_dqb.dqb_curspace;
  	dquot->dq_dqb.dqb_rsvspace += number;
  	dquot->dq_dqb.dqb_curspace -= 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);
  }
  
  struct dquot_warn {
  	struct super_block *w_sb;
  	struct kqid w_dq_id;
  	short w_type;
  };
  
  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_warn *warn)
  {
  	if (!flag_print_warnings)
  		return 0;
  
  	switch (warn->w_dq_id.type) {
  		case USRQUOTA:
  			return uid_eq(current_fsuid(), warn->w_dq_id.uid);
  		case GRPQUOTA:
  			return in_group_p(warn->w_dq_id.gid);
  		case PRJQUOTA:
  			return 1;
  	}
  	return 0;
  }
  
  /* Print warning to user which exceeded quota */
  static void print_warning(struct dquot_warn *warn)
  {
  	char *msg = NULL;
  	struct tty_struct *tty;
  	int warntype = warn->w_type;
  
  	if (warntype == QUOTA_NL_IHARDBELOW ||
  	    warntype == QUOTA_NL_ISOFTBELOW ||
  	    warntype == QUOTA_NL_BHARDBELOW ||
  	    warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
  		return;
  
  	tty = get_current_tty();
  	if (!tty)
  		return;
  	tty_write_message(tty, warn->w_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[warn->w_dq_id.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);
  	tty_kref_put(tty);
  }
  #endif
  
  static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
  			    int warntype)
  {
  	if (warning_issued(dquot, warntype))
  		return;
  	warn->w_type = warntype;
  	warn->w_sb = dquot->dq_sb;
  	warn->w_dq_id = dquot->dq_id;
  }
  
  /*
   * Write warnings to the console and send warning messages over netlink.
   *
   * Note that this function can call into tty and networking code.
   */
  static void flush_warnings(struct dquot_warn *warn)
  {
  	int i;
  
  	for (i = 0; i < MAXQUOTAS; i++) {
  		if (warn[i].w_type == QUOTA_NL_NOWARN)
  			continue;
  #ifdef CONFIG_PRINT_QUOTA_WARNING
  		print_warning(&warn[i]);
  #endif
  		quota_send_warning(warn[i].w_dq_id,
  				   warn[i].w_sb->s_dev, warn[i].w_type);
  	}
  }
  
  static int ignore_hardlimit(struct dquot *dquot)
  {
  	struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
  
  	return capable(CAP_SYS_RESOURCE) &&
  	       (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
  		!(info->dqi_flags & DQF_ROOT_SQUASH));
  }
  
  /* needs dq_data_lock */
  static int check_idq(struct dquot *dquot, qsize_t inodes,
  		     struct dquot_warn *warn)
  {
  	qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
  
  	if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.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)) {
  		prepare_warning(warn, dquot, 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)) {
  		prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
  		return -EDQUOT;
  	}
  
  	if (dquot->dq_dqb.dqb_isoftlimit &&
  	    newinodes > dquot->dq_dqb.dqb_isoftlimit &&
  	    dquot->dq_dqb.dqb_itime == 0) {
  		prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
  		dquot->dq_dqb.dqb_itime = get_seconds() +
  		    sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
  	}
  
  	return 0;
  }
  
  /* needs dq_data_lock */
  static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc,
  		     struct dquot_warn *warn)
  {
  	qsize_t tspace;
  	struct super_block *sb = dquot->dq_sb;
  
  	if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.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)
  			prepare_warning(warn, dquot, 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)
  			prepare_warning(warn, dquot, 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) {
  			prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
  			dquot->dq_dqb.dqb_btime = get_seconds() +
  			    sb_dqopt(sb)->info[dquot->dq_id.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_id.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
   *
   * 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 int __dquot_initialize(struct inode *inode, int type)
  {
  	int cnt, init_needed = 0;
  	struct dquot **dquots, *got[MAXQUOTAS] = {};
  	struct super_block *sb = inode->i_sb;
  	qsize_t rsv;
  	int ret = 0;
  
  	if (!dquot_active(inode))
  		return 0;
  
  	dquots = i_dquot(inode);
  
  	/* First get references to structures we might need. */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		struct kqid qid;
  		kprojid_t projid;
  		int rc;
  		struct dquot *dquot;
  
  		if (type != -1 && cnt != type)
  			continue;
  		/*
  		 * The i_dquot should have been initialized in most cases,
  		 * we check it without locking here to avoid unnecessary
  		 * dqget()/dqput() calls.
  		 */
  		if (dquots[cnt])
  			continue;
  
  		if (!sb_has_quota_active(sb, cnt))
  			continue;
  
  		init_needed = 1;
  
  		switch (cnt) {
  		case USRQUOTA:
  			qid = make_kqid_uid(inode->i_uid);
  			break;
  		case GRPQUOTA:
  			qid = make_kqid_gid(inode->i_gid);
  			break;
  		case PRJQUOTA:
  			rc = inode->i_sb->dq_op->get_projid(inode, &projid);
  			if (rc)
  				continue;
  			qid = make_kqid_projid(projid);
  			break;
  		}
  		dquot = dqget(sb, qid);
  		if (IS_ERR(dquot)) {
  			/* We raced with somebody turning quotas off... */
  			if (PTR_ERR(dquot) != -ESRCH) {
  				ret = PTR_ERR(dquot);
  				goto out_put;
  			}
  			dquot = NULL;
  		}
  		got[cnt] = dquot;
  	}
  
  	/* All required i_dquot has been initialized */
  	if (!init_needed)
  		return 0;
  
  	spin_lock(&dq_data_lock);
  	if (IS_NOQUOTA(inode))
  		goto out_lock;
  	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 (!dquots[cnt]) {
  			dquots[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(dquots[cnt], rsv);
  		}
  	}
  out_lock:
  	spin_unlock(&dq_data_lock);
  out_put:
  	/* Drop unused references */
  	dqput_all(got);
  
  	return ret;
  }
  
  int dquot_initialize(struct inode *inode)
  {
  	return __dquot_initialize(inode, -1);
  }
  EXPORT_SYMBOL(dquot_initialize);
  
  /*
   * Release all quotas referenced by inode.
   *
   * This function only be called on inode free or converting
   * a file to quota file, no other users for the i_dquot in
   * both cases, so we needn't call synchronize_srcu() after
   * clearing i_dquot.
   */
  static void __dquot_drop(struct inode *inode)
  {
  	int cnt;
  	struct dquot **dquots = i_dquot(inode);
  	struct dquot *put[MAXQUOTAS];
  
  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		put[cnt] = dquots[cnt];
  		dquots[cnt] = NULL;
  	}
  	spin_unlock(&dq_data_lock);
  	dqput_all(put);
  }
  
  void dquot_drop(struct inode *inode)
  {
  	struct dquot * const *dquots;
  	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.
  	 */
  	dquots = i_dquot(inode);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (dquots[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_reclaim_rsv_space(struct inode *inode, qsize_t number)
  {
  	spin_lock(&inode->i_lock);
  	*inode_reserved_space(inode) += number;
  	__inode_sub_bytes(inode, number);
  	spin_unlock(&inode->i_lock);
  }
  EXPORT_SYMBOL(inode_reclaim_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, index;
  	struct dquot_warn warn[MAXQUOTAS];
  	int reserve = flags & DQUOT_SPACE_RESERVE;
  	struct dquot **dquots;
  
  	if (!dquot_active(inode)) {
  		inode_incr_space(inode, number, reserve);
  		goto out;
  	}
  
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		warn[cnt].w_type = QUOTA_NL_NOWARN;
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (!dquots[cnt])
  			continue;
  		ret = check_bdq(dquots[cnt], number,
  				!(flags & DQUOT_SPACE_WARN), &warn[cnt]);
  		if (ret && !(flags & DQUOT_SPACE_NOFAIL)) {
  			spin_unlock(&dq_data_lock);
  			goto out_flush_warn;
  		}
  	}
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (!dquots[cnt])
  			continue;
  		if (reserve)
  			dquot_resv_space(dquots[cnt], number);
  		else
  			dquot_incr_space(dquots[cnt], number);
  	}
  	inode_incr_space(inode, number, reserve);
  	spin_unlock(&dq_data_lock);
  
  	if (reserve)
  		goto out_flush_warn;
  	mark_all_dquot_dirty(dquots);
  out_flush_warn:
  	srcu_read_unlock(&dquot_srcu, index);
  	flush_warnings(warn);
  out:
  	return ret;
  }
  EXPORT_SYMBOL(__dquot_alloc_space);
  
  /*
   * This operation can block, but only after everything is updated
   */
  int dquot_alloc_inode(struct inode *inode)
  {
  	int cnt, ret = 0, index;
  	struct dquot_warn warn[MAXQUOTAS];
  	struct dquot * const *dquots;
  
  	if (!dquot_active(inode))
  		return 0;
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		warn[cnt].w_type = QUOTA_NL_NOWARN;
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (!dquots[cnt])
  			continue;
  		ret = check_idq(dquots[cnt], 1, &warn[cnt]);
  		if (ret)
  			goto warn_put_all;
  	}
  
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (!dquots[cnt])
  			continue;
  		dquot_incr_inodes(dquots[cnt], 1);
  	}
  
  warn_put_all:
  	spin_unlock(&dq_data_lock);
  	if (ret == 0)
  		mark_all_dquot_dirty(dquots);
  	srcu_read_unlock(&dquot_srcu, index);
  	flush_warnings(warn);
  	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)
  {
  	struct dquot **dquots;
  	int cnt, index;
  
  	if (!dquot_active(inode)) {
  		inode_claim_rsv_space(inode, number);
  		return 0;
  	}
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	/* Claim reserved quotas to allocated quotas */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (dquots[cnt])
  			dquot_claim_reserved_space(dquots[cnt], number);
  	}
  	/* Update inode bytes */
  	inode_claim_rsv_space(inode, number);
  	spin_unlock(&dq_data_lock);
  	mark_all_dquot_dirty(dquots);
  	srcu_read_unlock(&dquot_srcu, index);
  	return 0;
  }
  EXPORT_SYMBOL(dquot_claim_space_nodirty);
  
  /*
   * Convert allocated space back to in-memory reserved quotas
   */
  void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
  {
  	struct dquot **dquots;
  	int cnt, index;
  
  	if (!dquot_active(inode)) {
  		inode_reclaim_rsv_space(inode, number);
  		return;
  	}
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	/* Claim reserved quotas to allocated quotas */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (dquots[cnt])
  			dquot_reclaim_reserved_space(dquots[cnt], number);
  	}
  	/* Update inode bytes */
  	inode_reclaim_rsv_space(inode, number);
  	spin_unlock(&dq_data_lock);
  	mark_all_dquot_dirty(dquots);
  	srcu_read_unlock(&dquot_srcu, index);
  	return;
  }
  EXPORT_SYMBOL(dquot_reclaim_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;
  	struct dquot_warn warn[MAXQUOTAS];
  	struct dquot **dquots;
  	int reserve = flags & DQUOT_SPACE_RESERVE, index;
  
  	if (!dquot_active(inode)) {
  		inode_decr_space(inode, number, reserve);
  		return;
  	}
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		int wtype;
  
  		warn[cnt].w_type = QUOTA_NL_NOWARN;
  		if (!dquots[cnt])
  			continue;
  		wtype = info_bdq_free(dquots[cnt], number);
  		if (wtype != QUOTA_NL_NOWARN)
  			prepare_warning(&warn[cnt], dquots[cnt], wtype);
  		if (reserve)
  			dquot_free_reserved_space(dquots[cnt], number);
  		else
  			dquot_decr_space(dquots[cnt], number);
  	}
  	inode_decr_space(inode, number, reserve);
  	spin_unlock(&dq_data_lock);
  
  	if (reserve)
  		goto out_unlock;
  	mark_all_dquot_dirty(dquots);
  out_unlock:
  	srcu_read_unlock(&dquot_srcu, index);
  	flush_warnings(warn);
  }
  EXPORT_SYMBOL(__dquot_free_space);
  
  /*
   * This operation can block, but only after everything is updated
   */
  void dquot_free_inode(struct inode *inode)
  {
  	unsigned int cnt;
  	struct dquot_warn warn[MAXQUOTAS];
  	struct dquot * const *dquots;
  	int index;
  
  	if (!dquot_active(inode))
  		return;
  
  	dquots = i_dquot(inode);
  	index = srcu_read_lock(&dquot_srcu);
  	spin_lock(&dq_data_lock);
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		int wtype;
  
  		warn[cnt].w_type = QUOTA_NL_NOWARN;
  		if (!dquots[cnt])
  			continue;
  		wtype = info_idq_free(dquots[cnt], 1);
  		if (wtype != QUOTA_NL_NOWARN)
  			prepare_warning(&warn[cnt], dquots[cnt], wtype);
  		dquot_decr_inodes(dquots[cnt], 1);
  	}
  	spin_unlock(&dq_data_lock);
  	mark_all_dquot_dirty(dquots);
  	srcu_read_unlock(&dquot_srcu, index);
  	flush_warnings(warn);
  }
  EXPORT_SYMBOL(dquot_free_inode);
  
  /*
   * Transfer the number of inode and blocks from one diskquota to an other.
   * On success, dquot references in transfer_to are consumed and references
   * to original dquots that need to be released are placed there. On failure,
   * references are kept untouched.
   *
   * This operation can block, but only after everything is updated
   * A transaction must be started when entering this function.
   *
   * We are holding reference on transfer_from & transfer_to, no need to
   * protect them by srcu_read_lock().
   */
  int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
  {
  	qsize_t space, cur_space;
  	qsize_t rsv_space = 0;
  	struct dquot *transfer_from[MAXQUOTAS] = {};
  	int cnt, ret = 0;
  	char is_valid[MAXQUOTAS] = {};
  	struct dquot_warn warn_to[MAXQUOTAS];
  	struct dquot_warn warn_from_inodes[MAXQUOTAS];
  	struct dquot_warn warn_from_space[MAXQUOTAS];
  
  	if (IS_NOQUOTA(inode))
  		return 0;
  	/* Initialize the arrays */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		warn_to[cnt].w_type = QUOTA_NL_NOWARN;
  		warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
  		warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
  	}
  
  	spin_lock(&dq_data_lock);
  	if (IS_NOQUOTA(inode)) {	/* File without quota accounting? */
  		spin_unlock(&dq_data_lock);
  		return 0;
  	}
  	cur_space = inode_get_bytes(inode);
  	rsv_space = inode_get_rsv_space(inode);
  	space = cur_space + rsv_space;
  	/* Build the transfer_from list and check the limits */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		/*
  		 * Skip changes for same uid or gid or for turned off quota-type.
  		 */
  		if (!transfer_to[cnt])
  			continue;
  		/* Avoid races with quotaoff() */
  		if (!sb_has_quota_active(inode->i_sb, cnt))
  			continue;
  		is_valid[cnt] = 1;
  		transfer_from[cnt] = i_dquot(inode)[cnt];
  		ret = check_idq(transfer_to[cnt], 1, &warn_to[cnt]);
  		if (ret)
  			goto over_quota;
  		ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
  		if (ret)
  			goto over_quota;
  	}
  
  	/*
  	 * Finally perform the needed transfer from transfer_from to transfer_to
  	 */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (!is_valid[cnt])
  			continue;
  		/* Due to IO error we might not have transfer_from[] structure */
  		if (transfer_from[cnt]) {
  			int wtype;
  			wtype = info_idq_free(transfer_from[cnt], 1);
  			if (wtype != QUOTA_NL_NOWARN)
  				prepare_warning(&warn_from_inodes[cnt],
  						transfer_from[cnt], wtype);
  			wtype = info_bdq_free(transfer_from[cnt], space);
  			if (wtype != QUOTA_NL_NOWARN)
  				prepare_warning(&warn_from_space[cnt],
  						transfer_from[cnt], wtype);
  			dquot_decr_inodes(transfer_from[cnt], 1);
  			dquot_decr_space(transfer_from[cnt], cur_space);
  			dquot_free_reserved_space(transfer_from[cnt],
  						  rsv_space);
  		}
  
  		dquot_incr_inodes(transfer_to[cnt], 1);
  		dquot_incr_space(transfer_to[cnt], cur_space);
  		dquot_resv_space(transfer_to[cnt], rsv_space);
  
  		i_dquot(inode)[cnt] = transfer_to[cnt];
  	}
  	spin_unlock(&dq_data_lock);
  
  	mark_all_dquot_dirty(transfer_from);
  	mark_all_dquot_dirty(transfer_to);
  	flush_warnings(warn_to);
  	flush_warnings(warn_from_inodes);
  	flush_warnings(warn_from_space);
  	/* Pass back references to put */
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		if (is_valid[cnt])
  			transfer_to[cnt] = transfer_from[cnt];
  	return 0;
  over_quota:
  	spin_unlock(&dq_data_lock);
  	flush_warnings(warn_to);
  	return ret;
  }
  EXPORT_SYMBOL(__dquot_transfer);
  
  /* Wrapper for transferring ownership of an inode for uid/gid only
   * Called from FSXXX_setattr()
   */
  int dquot_transfer(struct inode *inode, struct iattr *iattr)
  {
  	struct dquot *transfer_to[MAXQUOTAS] = {};
  	struct dquot *dquot;
  	struct super_block *sb = inode->i_sb;
  	int ret;
  
  	if (!dquot_active(inode))
  		return 0;
  
  	if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
  		dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
  		if (IS_ERR(dquot)) {
  			if (PTR_ERR(dquot) != -ESRCH) {
  				ret = PTR_ERR(dquot);
  				goto out_put;
  			}
  			dquot = NULL;
  		}
  		transfer_to[USRQUOTA] = dquot;
  	}
  	if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
  		dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
  		if (IS_ERR(dquot)) {
  			if (PTR_ERR(dquot) != -ESRCH) {
  				ret = PTR_ERR(dquot);
  				goto out_put;
  			}
  			dquot = NULL;
  		}
  		transfer_to[GRPQUOTA] = dquot;
  	}
  	ret = __dquot_transfer(inode, transfer_to);
  out_put:
  	dqput_all(transfer_to);
  	return ret;
  }
  EXPORT_SYMBOL(dquot_transfer);
  
  /*
   * 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;
  }
  EXPORT_SYMBOL(dquot_commit_info);
  
  /*
   * Definitions of diskquota operations.
   */
  const struct dquot_operations dquot_operations = {
  	.write_dquot	= dquot_commit,
  	.acquire_dquot	= dquot_acquire,
  	.release_dquot	= dquot_release,
  	.mark_dirty	= dquot_mark_dquot_dirty,
  	.write_info	= dquot_commit_info,
  	.alloc_dquot	= dquot_alloc,
  	.destroy_dquot	= dquot_destroy,
  };
  EXPORT_SYMBOL(dquot_operations);
  
  /*
   * Generic helper for ->open on filesystems supporting disk quotas.
   */
  int dquot_file_open(struct inode *inode, struct file *file)
  {
  	int error;
  
  	error = generic_file_open(inode, file);
  	if (!error && (file->f_mode & FMODE_WRITE))
  		dquot_initialize(inode);
  	return error;
  }
  EXPORT_SYMBOL(dquot_file_open);
  
  /*
   * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
   */
  int dquot_disable(struct super_block *sb, int type, unsigned int flags)
  {
  	int cnt, ret = 0;
  	struct quota_info *dqopt = sb_dqopt(sb);
  	struct inode *toputinode[MAXQUOTAS];
  
  	/* Cannot turn off usage accounting without turning off limits, or
  	 * suspend quotas and simultaneously turn quotas off. */
  	if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
  	    || (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
  	    DQUOT_USAGE_ENABLED)))
  		return -EINVAL;
  
  	/* We need to serialize quota_off() for device */
  	mutex_lock(&dqopt->dqonoff_mutex);
  
  	/*
  	 * Skip everything if there's nothing to do. We have to do this because
  	 * sometimes we are called when fill_super() failed and calling
  	 * sync_fs() in such cases does no good.
  	 */
  	if (!sb_any_quota_loaded(sb)) {
  		mutex_unlock(&dqopt->dqonoff_mutex);
  		return 0;
  	}
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		toputinode[cnt] = NULL;
  		if (type != -1 && cnt != type)
  			continue;
  		if (!sb_has_quota_loaded(sb, cnt))
  			continue;
  
  		if (flags & DQUOT_SUSPENDED) {
  			spin_lock(&dq_state_lock);
  			dqopt->flags |=
  				dquot_state_flag(DQUOT_SUSPENDED, cnt);
  			spin_unlock(&dq_state_lock);
  		} else {
  			spin_lock(&dq_state_lock);
  			dqopt->flags &= ~dquot_state_flag(flags, cnt);
  			/* Turning off suspended quotas? */
  			if (!sb_has_quota_loaded(sb, cnt) &&
  			    sb_has_quota_suspended(sb, cnt)) {
  				dqopt->flags &=	~dquot_state_flag(
  							DQUOT_SUSPENDED, cnt);
  				spin_unlock(&dq_state_lock);
  				iput(dqopt->files[cnt]);
  				dqopt->files[cnt] = NULL;
  				continue;
  			}
  			spin_unlock(&dq_state_lock);
  		}
  
  		/* We still have to keep quota loaded? */
  		if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
  			continue;
  
  		/* 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];
  		if (!sb_has_quota_loaded(sb, 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);
  
  	/* Skip syncing and setting flags if quota files are hidden */
  	if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
  		goto put_inodes;
  
  	/* 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_loaded(sb, cnt)) {
  				mutex_lock(&toputinode[cnt]->i_mutex);
  				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_sync(toputinode[cnt]);
  			}
  			mutex_unlock(&dqopt->dqonoff_mutex);
  		}
  	if (sb->s_bdev)
  		invalidate_bdev(sb->s_bdev);
  put_inodes:
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
  		if (toputinode[cnt]) {
  			/* On remount RO, we keep the inode pointer so that we
  			 * can reenable quota on the subsequent remount RW. We
  			 * have to check 'flags' variable and not use sb_has_
  			 * function because another quotaon / quotaoff could
  			 * change global state before we got here. We refuse
  			 * to suspend quotas when there is pending delete on
  			 * the quota file... */
  			if (!(flags & DQUOT_SUSPENDED))
  				iput(toputinode[cnt]);
  			else if (!toputinode[cnt]->i_nlink)
  				ret = -EBUSY;
  		}
  	return ret;
  }
  EXPORT_SYMBOL(dquot_disable);
  
  int dquot_quota_off(struct super_block *sb, int type)
  {
  	return dquot_disable(sb, type,
  			     DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
  }
  EXPORT_SYMBOL(dquot_quota_off);
  
  /*
   *	Turn quotas on on a device
   */
  
  /*
   * Helper function to turn quotas on when we already have the inode of
   * quota file and no quota information is loaded.
   */
  static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
  	unsigned int flags)
  {
  	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 ||
  	    (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
  		error = -EINVAL;
  		goto out_fmt;
  	}
  	/* Usage always has to be set... */
  	if (!(flags & DQUOT_USAGE_ENABLED)) {
  		error = -EINVAL;
  		goto out_fmt;
  	}
  
  	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
  		/* As we bypass the pagecache we must now flush all the
  		 * dirty data and invalidate caches so that kernel sees
  		 * changes from userspace. It is not enough to just flush
  		 * the quota file since if blocksize < pagesize, invalidation
  		 * of the cache could fail because of other unrelated dirty
  		 * data */
  		sync_filesystem(sb);
  		invalidate_bdev(sb->s_bdev);
  	}
  	mutex_lock(&dqopt->dqonoff_mutex);
  	if (sb_has_quota_loaded(sb, type)) {
  		error = -EBUSY;
  		goto out_lock;
  	}
  
  	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
  		/* 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. */
  		mutex_lock(&inode->i_mutex);
  		oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE |
  					     S_NOQUOTA);
  		inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
  		mutex_unlock(&inode->i_mutex);
  		/*
  		 * When S_NOQUOTA is set, remove dquot references as no more
  		 * references can be added
  		 */
  		__dquot_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;
  	dqopt->info[type].dqi_fmt_id = format_id;
  	INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
  	mutex_lock(&dqopt->dqio_mutex);
  	error = dqopt->ops[type]->read_file_info(sb, type);
  	if (error < 0) {
  		mutex_unlock(&dqopt->dqio_mutex);
  		goto out_file_init;
  	}
  	if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
  		dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
  	mutex_unlock(&dqopt->dqio_mutex);
  	spin_lock(&dq_state_lock);
  	dqopt->flags |= dquot_state_flag(flags, type);
  	spin_unlock(&dq_state_lock);
  
  	add_dquot_ref(sb, type);
  	mutex_unlock(&dqopt->dqonoff_mutex);
  
  	return 0;
  
  out_file_init:
  	dqopt->files[type] = NULL;
  	iput(inode);
  out_lock:
  	if (oldflags != -1) {
  		mutex_lock(&inode->i_mutex);
  		/* 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;
  		mutex_unlock(&inode->i_mutex);
  	}
  	mutex_unlock(&dqopt->dqonoff_mutex);
  out_fmt:
  	put_quota_format(fmt);
  
  	return error; 
  }
  
  /* Reenable quotas on remount RW */
  int dquot_resume(struct super_block *sb, int type)
  {
  	struct quota_info *dqopt = sb_dqopt(sb);
  	struct inode *inode;
  	int ret = 0, cnt;
  	unsigned int flags;
  
  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
  		if (type != -1 && cnt != type)
  			continue;
  
  		mutex_lock(&dqopt->dqonoff_mutex);
  		if (!sb_has_quota_suspended(sb, cnt)) {
  			mutex_unlock(&dqopt->dqonoff_mutex);
  			continue;
  		}
  		inode = dqopt->files[cnt];
  		dqopt->files[cnt] = NULL;
  		spin_lock(&dq_state_lock);
  		flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
  							DQUOT_LIMITS_ENABLED,
  							cnt);
  		dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
  		spin_unlock(&dq_state_lock);
  		mutex_unlock(&dqopt->dqonoff_mutex);
  
  		flags = dquot_generic_flag(flags, cnt);
  		ret = vfs_load_quota_inode(inode, cnt,
  				dqopt->info[cnt].dqi_fmt_id, flags);
  		iput(inode);
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL(dquot_resume);
  
  int dquot_quota_on(struct super_block *sb, int type, int format_id,
  		   struct path *path)
  {
  	int error = security_quota_on(path->dentry);
  	if (error)
  		return error;
  	/* Quota file not on the same filesystem? */
  	if (path->dentry->d_sb != sb)
  		error = -EXDEV;
  	else
  		error = vfs_load_quota_inode(d_inode(path->dentry), type,
  					     format_id, DQUOT_USAGE_ENABLED |
  					     DQUOT_LIMITS_ENABLED);
  	return error;
  }
  EXPORT_SYMBOL(dquot_quota_on);
  
  /*
   * More powerful function for turning on quotas allowing setting
   * of individual quota flags
   */
  int dquot_enable(struct inode *inode, int type, int format_id,
  		 unsigned int flags)
  {
  	int ret = 0;
  	struct super_block *sb = inode->i_sb;
  	struct quota_info *dqopt = sb_dqopt(sb);
  
  	/* Just unsuspend quotas? */
  	BUG_ON(flags & DQUOT_SUSPENDED);
  
  	if (!flags)
  		return 0;
  	/* Just updating flags needed? */
  	if (sb_has_quota_loaded(sb, type)) {
  		mutex_lock(&dqopt->dqonoff_mutex);
  		/* Now do a reliable test... */
  		if (!sb_has_quota_loaded(sb, type)) {
  			mutex_unlock(&dqopt->dqonoff_mutex);
  			goto load_quota;
  		}
  		if (flags & DQUOT_USAGE_ENABLED &&
  		    sb_has_quota_usage_enabled(sb, type)) {
  			ret = -EBUSY;
  			goto out_lock;
  		}
  		if (flags & DQUOT_LIMITS_ENABLED &&
  		    sb_has_quota_limits_enabled(sb, type)) {
  			ret = -EBUSY;
  			goto out_lock;
  		}
  		spin_lock(&dq_state_lock);
  		sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
  		spin_unlock(&dq_state_lock);
  out_lock:
  		mutex_unlock(&dqopt->dqonoff_mutex);
  		return ret;
  	}
  
  load_quota:
  	return vfs_load_quota_inode(inode, type, format_id, flags);
  }
  EXPORT_SYMBOL(dquot_enable);
  
  /*
   * This function is used when filesystem needs to initialize quotas
   * during mount time.
   */
  int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
  		int format_id, int type)
  {
  	struct dentry *dentry;
  	int error;
  
  	mutex_lock(&d_inode(sb->s_root)->i_mutex);
  	dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
  	mutex_unlock(&d_inode(sb->s_root)->i_mutex);
  	if (IS_ERR(dentry))
  		return PTR_ERR(dentry);
  
  	if (d_really_is_negative(dentry)) {
  		error = -ENOENT;
  		goto out;
  	}
  
  	error = security_quota_on(dentry);
  	if (!error)
  		error = vfs_load_quota_inode(d_inode(dentry), type, format_id,
  				DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
  
  out:
  	dput(dentry);
  	return error;
  }
  EXPORT_SYMBOL(dquot_quota_on_mount);
  
  static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
  {
  	int ret;
  	int type;
  	struct quota_info *dqopt = sb_dqopt(sb);
  
  	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
  		return -ENOSYS;
  	/* Accounting cannot be turned on while fs is mounted */
  	flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
  	if (!flags)
  		return -EINVAL;
  	for (type = 0; type < MAXQUOTAS; type++) {
  		if (!(flags & qtype_enforce_flag(type)))
  			continue;
  		/* Can't enforce without accounting */
  		if (!sb_has_quota_usage_enabled(sb, type))
  			return -EINVAL;
  		ret = dquot_enable(dqopt->files[type], type,
  				   dqopt->info[type].dqi_fmt_id,
  				   DQUOT_LIMITS_ENABLED);
  		if (ret < 0)
  			goto out_err;
  	}
  	return 0;
  out_err:
  	/* Backout enforcement enablement we already did */
  	for (type--; type >= 0; type--)  {
  		if (flags & qtype_enforce_flag(type))
  			dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
  	}
  	/* Error code translation for better compatibility with XFS */
  	if (ret == -EBUSY)
  		ret = -EEXIST;
  	return ret;
  }
  
  static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
  {
  	int ret;
  	int type;
  	struct quota_info *dqopt = sb_dqopt(sb);
  
  	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
  		return -ENOSYS;
  	/*
  	 * We don't support turning off accounting via quotactl. In principle
  	 * quota infrastructure can do this but filesystems don't expect
  	 * userspace to be able to do it.
  	 */
  	if (flags &
  		  (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
  		return -EOPNOTSUPP;
  
  	/* Filter out limits not enabled */
  	for (type = 0; type < MAXQUOTAS; type++)
  		if (!sb_has_quota_limits_enabled(sb, type))
  			flags &= ~qtype_enforce_flag(type);
  	/* Nothing left? */
  	if (!flags)
  		return -EEXIST;
  	for (type = 0; type < MAXQUOTAS; type++) {
  		if (flags & qtype_enforce_flag(type)) {
  			ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
  			if (ret < 0)
  				goto out_err;
  		}
  	}
  	return 0;
  out_err:
  	/* Backout enforcement disabling we already did */
  	for (type--; type >= 0; type--)  {
  		if (flags & qtype_enforce_flag(type))
  			dquot_enable(dqopt->files[type], type,
  				     dqopt->info[type].dqi_fmt_id,
  				     DQUOT_LIMITS_ENABLED);
  	}
  	return ret;
  }
  
  /* Generic routine for getting common part of quota structure */
  static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
  {
  	struct mem_dqblk *dm = &dquot->dq_dqb;
  
  	memset(di, 0, sizeof(*di));
  	spin_lock(&dq_data_lock);
  	di->d_spc_hardlimit = dm->dqb_bhardlimit;
  	di->d_spc_softlimit = dm->dqb_bsoftlimit;
  	di->d_ino_hardlimit = dm->dqb_ihardlimit;
  	di->d_ino_softlimit = dm->dqb_isoftlimit;
  	di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
  	di->d_ino_count = dm->dqb_curinodes;
  	di->d_spc_timer = dm->dqb_btime;
  	di->d_ino_timer = dm->dqb_itime;
  	spin_unlock(&dq_data_lock);
  }
  
  int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
  		    struct qc_dqblk *di)
  {
  	struct dquot *dquot;
  
  	dquot = dqget(sb, qid);
  	if (IS_ERR(dquot))
  		return PTR_ERR(dquot);
  	do_get_dqblk(dquot, di);
  	dqput(dquot);
  
  	return 0;
  }
  EXPORT_SYMBOL(dquot_get_dqblk);
  
  #define VFS_QC_MASK \
  	(QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
  	 QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
  	 QC_SPC_TIMER | QC_INO_TIMER)
  
  /* Generic routine for setting common part of quota structure */
  static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
  {
  	struct mem_dqblk *dm = &dquot->dq_dqb;
  	int check_blim = 0, check_ilim = 0;
  	struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
  
  	if (di->d_fieldmask & ~VFS_QC_MASK)
  		return -EINVAL;
  
  	if (((di->d_fieldmask & QC_SPC_SOFT) &&
  	     di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
  	    ((di->d_fieldmask & QC_SPC_HARD) &&
  	     di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
  	    ((di->d_fieldmask & QC_INO_SOFT) &&
  	     (di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
  	    ((di->d_fieldmask & QC_INO_HARD) &&
  	     (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
  		return -ERANGE;
  
  	spin_lock(&dq_data_lock);
  	if (di->d_fieldmask & QC_SPACE) {
  		dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
  		check_blim = 1;
  		set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
  	}
  
  	if (di->d_fieldmask & QC_SPC_SOFT)
  		dm->dqb_bsoftlimit = di->d_spc_softlimit;
  	if (di->d_fieldmask & QC_SPC_HARD)
  		dm->dqb_bhardlimit = di->d_spc_hardlimit;
  	if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
  		check_blim = 1;
  		set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
  	}
  
  	if (di->d_fieldmask & QC_INO_COUNT) {
  		dm->dqb_curinodes = di->d_ino_count;
  		check_ilim = 1;
  		set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
  	}
  
  	if (di->d_fieldmask & QC_INO_SOFT)
  		dm->dqb_isoftlimit = di->d_ino_softlimit;
  	if (di->d_fieldmask & QC_INO_HARD)
  		dm->dqb_ihardlimit = di->d_ino_hardlimit;
  	if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
  		check_ilim = 1;
  		set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
  	}
  
  	if (di->d_fieldmask & QC_SPC_TIMER) {
  		dm->dqb_btime = di->d_spc_timer;
  		check_blim = 1;
  		set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
  	}
  
  	if (di->d_fieldmask & QC_INO_TIMER) {
  		dm->dqb_itime = di->d_ino_timer;
  		check_ilim = 1;
  		set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
  	}
  
  	if (check_blim) {
  		if (!dm->dqb_bsoftlimit ||
  		    dm->dqb_curspace < dm->dqb_bsoftlimit) {
  			dm->dqb_btime = 0;
  			clear_bit(DQ_BLKS_B, &dquot->dq_flags);
  		} else if (!(di->d_fieldmask & QC_SPC_TIMER))
  			/* Set grace only if user hasn't provided his own... */
  			dm->dqb_btime = get_seconds() + dqi->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->d_fieldmask & QC_INO_TIMER))
  			/* Set grace only if user hasn't provided his own... */
  			dm->dqb_itime = get_seconds() + dqi->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);
  
  	return 0;
  }
  
  int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
  		  struct qc_dqblk *di)
  {
  	struct dquot *dquot;
  	int rc;
  
  	dquot = dqget(sb, qid);
  	if (IS_ERR(dquot)) {
  		rc = PTR_ERR(dquot);
  		goto out;
  	}
  	rc = do_set_dqblk(dquot, di);
  	dqput(dquot);
  out:
  	return rc;
  }
  EXPORT_SYMBOL(dquot_set_dqblk);
  
  /* Generic routine for getting common part of quota file information */
  int dquot_get_state(struct super_block *sb, struct qc_state *state)
  {
  	struct mem_dqinfo *mi;
  	struct qc_type_state *tstate;
  	struct quota_info *dqopt = sb_dqopt(sb);
  	int type;
    
  	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  	memset(state, 0, sizeof(*state));
  	for (type = 0; type < MAXQUOTAS; type++) {
  		if (!sb_has_quota_active(sb, type))
  			continue;
  		tstate = state->s_state + type;
  		mi = sb_dqopt(sb)->info + type;
  		tstate->flags = QCI_ACCT_ENABLED;
  		spin_lock(&dq_data_lock);
  		if (mi->dqi_flags & DQF_SYS_FILE)
  			tstate->flags |= QCI_SYSFILE;
  		if (mi->dqi_flags & DQF_ROOT_SQUASH)
  			tstate->flags |= QCI_ROOT_SQUASH;
  		if (sb_has_quota_limits_enabled(sb, type))
  			tstate->flags |= QCI_LIMITS_ENFORCED;
  		tstate->spc_timelimit = mi->dqi_bgrace;
  		tstate->ino_timelimit = mi->dqi_igrace;
  		tstate->ino = dqopt->files[type]->i_ino;
  		tstate->blocks = dqopt->files[type]->i_blocks;
  		tstate->nextents = 1;	/* We don't know... */
  		spin_unlock(&dq_data_lock);
  	}
  	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
  	return 0;
  }
  EXPORT_SYMBOL(dquot_get_state);
  
  /* Generic routine for setting common part of quota file information */
  int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
  {
  	struct mem_dqinfo *mi;
  	int err = 0;
  
  	if ((ii->i_fieldmask & QC_WARNS_MASK) ||
  	    (ii->i_fieldmask & QC_RT_SPC_TIMER))
  		return -EINVAL;
  	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  	if (!sb_has_quota_active(sb, type)) {
  		err = -ESRCH;
  		goto out;
  	}
  	mi = sb_dqopt(sb)->info + type;
  	if (ii->i_fieldmask & QC_FLAGS) {
  		if ((ii->i_flags & QCI_ROOT_SQUASH &&
  		     mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD)) {
  			err = -EINVAL;
  			goto out;
  		}
  	}
  	spin_lock(&dq_data_lock);
  	if (ii->i_fieldmask & QC_SPC_TIMER)
  		mi->dqi_bgrace = ii->i_spc_timelimit;
  	if (ii->i_fieldmask & QC_INO_TIMER)
  		mi->dqi_igrace = ii->i_ino_timelimit;
  	if (ii->i_fieldmask & QC_FLAGS) {
  		if (ii->i_flags & QCI_ROOT_SQUASH)
  			mi->dqi_flags |= DQF_ROOT_SQUASH;
  		else
  			mi->dqi_flags &= ~DQF_ROOT_SQUASH;
  	}
  	spin_unlock(&dq_data_lock);
  	mark_info_dirty(sb, type);
  	/* Force write to disk */
  	sb->dq_op->write_info(sb, type);
  out:
  	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
  	return err;
  }
  EXPORT_SYMBOL(dquot_set_dqinfo);
  
  const struct quotactl_ops dquot_quotactl_ops = {
  	.quota_on	= dquot_quota_on,
  	.quota_off	= dquot_quota_off,
  	.quota_sync	= dquot_quota_sync,
  	.get_state	= dquot_get_state,
  	.set_info	= dquot_set_dqinfo,
  	.get_dqblk	= dquot_get_dqblk,
  	.set_dqblk	= dquot_set_dqblk
  };
  EXPORT_SYMBOL(dquot_quotactl_ops);
  
  const struct quotactl_ops dquot_quotactl_sysfile_ops = {
  	.quota_enable	= dquot_quota_enable,
  	.quota_disable	= dquot_quota_disable,
  	.quota_sync	= dquot_quota_sync,
  	.get_state	= dquot_get_state,
  	.set_info	= dquot_set_dqinfo,
  	.get_dqblk	= dquot_get_dqblk,
  	.set_dqblk	= dquot_set_dqblk
  };
  EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
  
  static int do_proc_dqstats(struct ctl_table *table, int write,
  		     void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	unsigned int type = (int *)table->data - dqstats.stat;
  
  	/* Update global table */
  	dqstats.stat[type] =
  			percpu_counter_sum_positive(&dqstats.counter[type]);
  	return proc_dointvec(table, write, buffer, lenp, ppos);
  }
  
  static struct ctl_table fs_dqstats_table[] = {
  	{
  		.procname	= "lookups",
  		.data		= &dqstats.stat[DQST_LOOKUPS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "drops",
  		.data		= &dqstats.stat[DQST_DROPS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "reads",
  		.data		= &dqstats.stat[DQST_READS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "writes",
  		.data		= &dqstats.stat[DQST_WRITES],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "cache_hits",
  		.data		= &dqstats.stat[DQST_CACHE_HITS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "allocated_dquots",
  		.data		= &dqstats.stat[DQST_ALLOC_DQUOTS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "free_dquots",
  		.data		= &dqstats.stat[DQST_FREE_DQUOTS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  	{
  		.procname	= "syncs",
  		.data		= &dqstats.stat[DQST_SYNCS],
  		.maxlen		= sizeof(int),
  		.mode		= 0444,
  		.proc_handler	= do_proc_dqstats,
  	},
  #ifdef CONFIG_PRINT_QUOTA_WARNING
  	{
  		.procname	= "warnings",
  		.data		= &flag_print_warnings,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  #endif
  	{ },
  };
  
  static struct ctl_table fs_table[] = {
  	{
  		.procname	= "quota",
  		.mode		= 0555,
  		.child		= fs_dqstats_table,
  	},
  	{ },
  };
  
  static struct ctl_table sys_table[] = {
  	{
  		.procname	= "fs",
  		.mode		= 0555,
  		.child		= fs_table,
  	},
  	{ },
  };
  
  static int __init dquot_init(void)
  {
  	int i, ret;
  	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");
  
  	for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
  		ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
  		if (ret)
  			panic("Cannot create dquot stat counters");
  	}
  
  	/* 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);
  
  	pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
  		" %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
  
  	register_shrinker(&dqcache_shrinker);
  
  	return 0;
  }
  module_init(dquot_init);
  