/*
   * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   * All Rights Reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #ifndef __XFS_DQUOT_H__
  #define __XFS_DQUOT_H__
  
  /*
   * Dquots are structures that hold quota information about a user or a group,
   * much like inodes are for files. In fact, dquots share many characteristics
   * with inodes. However, dquots can also be a centralized resource, relative
   * to a collection of inodes. In this respect, dquots share some characteristics
   * of the superblock.
   * XFS dquots exploit both those in its algorithms. They make every attempt
   * to not be a bottleneck when quotas are on and have minimal impact, if any,
   * when quotas are off.
   */
  
  struct xfs_mount;
  struct xfs_trans;
  
  enum {
  	XFS_QLOWSP_1_PCNT = 0,
  	XFS_QLOWSP_3_PCNT,
  	XFS_QLOWSP_5_PCNT,
  	XFS_QLOWSP_MAX
  };
  
  /*
   * The incore dquot structure
   */
  typedef struct xfs_dquot {
  	uint		 dq_flags;	/* various flags (XFS_DQ_*) */
  	struct list_head q_lru;		/* global free list of dquots */
  	struct xfs_mount*q_mount;	/* filesystem this relates to */
  	struct xfs_trans*q_transp;	/* trans this belongs to currently */
  	uint		 q_nrefs;	/* # active refs from inodes */
  	xfs_daddr_t	 q_blkno;	/* blkno of dquot buffer */
  	int		 q_bufoffset;	/* off of dq in buffer (# dquots) */
  	xfs_fileoff_t	 q_fileoffset;	/* offset in quotas file */
  
  	struct xfs_dquot*q_gdquot;	/* group dquot, hint only */
  	struct xfs_dquot*q_pdquot;	/* project dquot, hint only */
  	xfs_disk_dquot_t q_core;	/* actual usage & quotas */
  	xfs_dq_logitem_t q_logitem;	/* dquot log item */
  	xfs_qcnt_t	 q_res_bcount;	/* total regular nblks used+reserved */
  	xfs_qcnt_t	 q_res_icount;	/* total inos allocd+reserved */
  	xfs_qcnt_t	 q_res_rtbcount;/* total realtime blks used+reserved */
  	xfs_qcnt_t	 q_prealloc_lo_wmark;/* prealloc throttle wmark */
  	xfs_qcnt_t	 q_prealloc_hi_wmark;/* prealloc disabled wmark */
  	int64_t		 q_low_space[XFS_QLOWSP_MAX];
  	struct mutex	 q_qlock;	/* quota lock */
  	struct completion q_flush;	/* flush completion queue */
  	atomic_t          q_pincount;	/* dquot pin count */
  	wait_queue_head_t q_pinwait;	/* dquot pinning wait queue */
  } xfs_dquot_t;
  
  /*
   * Lock hierarchy for q_qlock:
   *	XFS_QLOCK_NORMAL is the implicit default,
   * 	XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
   */
  enum {
  	XFS_QLOCK_NORMAL = 0,
  	XFS_QLOCK_NESTED,
  };
  
  /*
   * Manage the q_flush completion queue embedded in the dquot.  This completion
   * queue synchronizes processes attempting to flush the in-core dquot back to
   * disk.
   */
  static inline void xfs_dqflock(xfs_dquot_t *dqp)
  {
  	wait_for_completion(&dqp->q_flush);
  }
  
  static inline int xfs_dqflock_nowait(xfs_dquot_t *dqp)
  {
  	return try_wait_for_completion(&dqp->q_flush);
  }
  
  static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
  {
  	complete(&dqp->q_flush);
  }
  
  static inline int xfs_dqlock_nowait(struct xfs_dquot *dqp)
  {
  	return mutex_trylock(&dqp->q_qlock);
  }
  
  static inline void xfs_dqlock(struct xfs_dquot *dqp)
  {
  	mutex_lock(&dqp->q_qlock);
  }
  
  static inline void xfs_dqunlock(struct xfs_dquot *dqp)
  {
  	mutex_unlock(&dqp->q_qlock);
  }
  
  static inline int xfs_this_quota_on(struct xfs_mount *mp, int type)
  {
  	switch (type & XFS_DQ_ALLTYPES) {
  	case XFS_DQ_USER:
  		return XFS_IS_UQUOTA_ON(mp);
  	case XFS_DQ_GROUP:
  		return XFS_IS_GQUOTA_ON(mp);
  	case XFS_DQ_PROJ:
  		return XFS_IS_PQUOTA_ON(mp);
  	default:
  		return 0;
  	}
  }
  
  static inline xfs_dquot_t *xfs_inode_dquot(struct xfs_inode *ip, int type)
  {
  	switch (type & XFS_DQ_ALLTYPES) {
  	case XFS_DQ_USER:
  		return ip->i_udquot;
  	case XFS_DQ_GROUP:
  		return ip->i_gdquot;
  	case XFS_DQ_PROJ:
  		return ip->i_pdquot;
  	default:
  		return NULL;
  	}
  }
  
  #define XFS_DQ_IS_LOCKED(dqp)	(mutex_is_locked(&((dqp)->q_qlock)))
  #define XFS_DQ_IS_DIRTY(dqp)	((dqp)->dq_flags & XFS_DQ_DIRTY)
  #define XFS_QM_ISUDQ(dqp)	((dqp)->dq_flags & XFS_DQ_USER)
  #define XFS_QM_ISPDQ(dqp)	((dqp)->dq_flags & XFS_DQ_PROJ)
  #define XFS_QM_ISGDQ(dqp)	((dqp)->dq_flags & XFS_DQ_GROUP)
  
  extern int		xfs_qm_dqread(struct xfs_mount *, xfs_dqid_t, uint,
  					uint, struct xfs_dquot	**);
  extern void		xfs_qm_dqdestroy(xfs_dquot_t *);
  extern int		xfs_qm_dqflush(struct xfs_dquot *, struct xfs_buf **);
  extern void		xfs_qm_dqunpin_wait(xfs_dquot_t *);
  extern void		xfs_qm_adjust_dqtimers(xfs_mount_t *,
  					xfs_disk_dquot_t *);
  extern void		xfs_qm_adjust_dqlimits(struct xfs_mount *,
  					       struct xfs_dquot *);
  extern int		xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
  					xfs_dqid_t, uint, uint, xfs_dquot_t **);
  extern void		xfs_qm_dqput(xfs_dquot_t *);
  
  extern void		xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
  
  extern void		xfs_dquot_set_prealloc_limits(struct xfs_dquot *);
  
  static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
  {
  	xfs_dqlock(dqp);
  	dqp->q_nrefs++;
  	xfs_dqunlock(dqp);
  	return dqp;
  }
  
  #endif /* __XFS_DQUOT_H__ */