fs/xfs/xfs_dquot.h

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_DQUOT_H__
  19 #define __XFS_DQUOT_H__
  20
  21 /*
  22  * Dquots are structures that hold quota information about a user or a group,
  23  * much like inodes are for files. In fact, dquots share many characteristics
  24  * with inodes. However, dquots can also be a centralized resource, relative
  25  * to a collection of inodes. In this respect, dquots share some characteristics
  26  * of the superblock.
  27  * XFS dquots exploit both those in its algorithms. They make every attempt
  28  * to not be a bottleneck when quotas are on and have minimal impact, if any,
  29  * when quotas are off.
  30  */
  31
  32 /*
  33  * The hash chain headers (hash buckets)
  34  */
  35 typedef struct xfs_dqhash {
  36         struct list_head  qh_list;
  37         struct mutex      qh_lock;
  38         uint              qh_version;   /* ever increasing version */
  39         uint              qh_nelems;    /* number of dquots on the list */
  40 } xfs_dqhash_t;
  41
  42 struct xfs_mount;
  43 struct xfs_trans;
  44
  45 /*
  46  * The incore dquot structure
  47  */
  48 typedef struct xfs_dquot {
  49         uint             dq_flags;      /* various flags (XFS_DQ_*) */
  50         struct list_head q_freelist;    /* global free list of dquots */
  51         struct list_head q_mplist;      /* mount's list of dquots */
  52         struct list_head q_hashlist;    /* gloabl hash list of dquots */
  53         xfs_dqhash_t    *q_hash;        /* the hashchain header */
  54         struct xfs_mount*q_mount;       /* filesystem this relates to */
  55         struct xfs_trans*q_transp;      /* trans this belongs to currently */
  56         uint             q_nrefs;       /* # active refs from inodes */
  57         xfs_daddr_t      q_blkno;       /* blkno of dquot buffer */
  58         int              q_bufoffset;   /* off of dq in buffer (# dquots) */
  59         xfs_fileoff_t    q_fileoffset;  /* offset in quotas file */
  60
  61         struct xfs_dquot*q_gdquot;      /* group dquot, hint only */
  62         xfs_disk_dquot_t q_core;        /* actual usage & quotas */
  63         xfs_dq_logitem_t q_logitem;     /* dquot log item */
  64         xfs_qcnt_t       q_res_bcount;  /* total regular nblks used+reserved */
  65         xfs_qcnt_t       q_res_icount;  /* total inos allocd+reserved */
  66         xfs_qcnt_t       q_res_rtbcount;/* total realtime blks used+reserved */
  67         struct mutex     q_qlock;       /* quota lock */
  68         struct completion q_flush;      /* flush completion queue */
  69         atomic_t          q_pincount;   /* dquot pin count */
  70         wait_queue_head_t q_pinwait;    /* dquot pinning wait queue */
  71 } xfs_dquot_t;
  72
  73 /*
  74  * Lock hierarchy for q_qlock:
  75  *      XFS_QLOCK_NORMAL is the implicit default,
  76  *      XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
  77  */
  78 enum {
  79         XFS_QLOCK_NORMAL = 0,
  80         XFS_QLOCK_NESTED,
  81 };
  82
  83 /*
  84  * Manage the q_flush completion queue embedded in the dquot.  This completion
  85  * queue synchronizes processes attempting to flush the in-core dquot back to
  86  * disk.
  87  */
  88 static inline void xfs_dqflock(xfs_dquot_t *dqp)
  89 {
  90         wait_for_completion(&dqp->q_flush);
  91 }
  92
  93 static inline int xfs_dqflock_nowait(xfs_dquot_t *dqp)
  94 {
  95         return try_wait_for_completion(&dqp->q_flush);
  96 }
  97
  98 static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
  99 {
 100         complete(&dqp->q_flush);
 101 }
 102
 103 static inline int xfs_dqlock_nowait(struct xfs_dquot *dqp)
 104 {
 105         return mutex_trylock(&dqp->q_qlock);
 106 }
 107
 108 static inline void xfs_dqlock(struct xfs_dquot *dqp)
 109 {
 110         mutex_lock(&dqp->q_qlock);
 111 }
 112
 113 static inline void xfs_dqunlock_nonotify(struct xfs_dquot *dqp)
 114 {
 115         mutex_unlock(&dqp->q_qlock);
 116 }
 117
 118 #define XFS_DQ_IS_LOCKED(dqp)   (mutex_is_locked(&((dqp)->q_qlock)))
 119 #define XFS_DQ_IS_DIRTY(dqp)    ((dqp)->dq_flags & XFS_DQ_DIRTY)
 120 #define XFS_QM_ISUDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_USER)
 121 #define XFS_QM_ISPDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_PROJ)
 122 #define XFS_QM_ISGDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_GROUP)
 123 #define XFS_DQ_TO_QINF(dqp)     ((dqp)->q_mount->m_quotainfo)
 124 #define XFS_DQ_TO_QIP(dqp)      (XFS_QM_ISUDQ(dqp) ? \
 125                                  XFS_DQ_TO_QINF(dqp)->qi_uquotaip : \
 126                                  XFS_DQ_TO_QINF(dqp)->qi_gquotaip)
 127
 128 #define XFS_IS_THIS_QUOTA_OFF(d) (! (XFS_QM_ISUDQ(d) ? \
 129                                      (XFS_IS_UQUOTA_ON((d)->q_mount)) : \
 130                                      (XFS_IS_OQUOTA_ON((d)->q_mount))))
 131
 132 extern int              xfs_qm_dqread(struct xfs_mount *, xfs_dqid_t, uint,
 133                                         uint, struct xfs_dquot  **);
 134 extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
 135 extern int              xfs_qm_dqflush(xfs_dquot_t *, uint);
 136 extern void             xfs_qm_dqpurge(xfs_dquot_t *);
 137 extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
 138 extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
 139                                         xfs_disk_dquot_t *);
 140 extern void             xfs_qm_adjust_dqlimits(xfs_mount_t *,
 141                                         xfs_disk_dquot_t *);
 142 extern int              xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
 143                                         xfs_dqid_t, uint, uint, xfs_dquot_t **);
 144 extern void             xfs_qm_dqput(xfs_dquot_t *);
 145
 146 extern void             xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
 147 extern void             xfs_dqunlock(struct xfs_dquot *);
 148 extern void             xfs_dqflock_pushbuf_wait(struct xfs_dquot *dqp);
 149
 150 static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
 151 {
 152         xfs_dqlock(dqp);
 153         dqp->q_nrefs++;
 154         xfs_dqunlock(dqp);
 155         return dqp;
 156 }
 157
 158 #endif /* __XFS_DQUOT_H__ */