fs/xfs/quota/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 xfs_dquot *qh_next;
  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 typedef struct xfs_dqlink {
  43         struct xfs_dquot  *ql_next;     /* forward link */
  44         struct xfs_dquot **ql_prevp;    /* pointer to prev ql_next */
  45 } xfs_dqlink_t;
  46
  47 struct xfs_mount;
  48 struct xfs_trans;
  49
  50 /*
  51  * This is the marker which is designed to occupy the first few
  52  * bytes of the xfs_dquot_t structure. Even inside this, the freelist pointers
  53  * must come first.
  54  * This serves as the marker ("sentinel") when we have to restart list
  55  * iterations because of locking considerations.
  56  */
  57 typedef struct xfs_dqmarker {
  58         struct xfs_dquot*dqm_flnext;    /* link to freelist: must be first */
  59         struct xfs_dquot*dqm_flprev;
  60         xfs_dqlink_t     dqm_mplist;    /* link to mount's list of dquots */
  61         xfs_dqlink_t     dqm_hashlist;  /* link to the hash chain */
  62         uint             dqm_flags;     /* various flags (XFS_DQ_*) */
  63 } xfs_dqmarker_t;
  64
  65 /*
  66  * The incore dquot structure
  67  */
  68 typedef struct xfs_dquot {
  69         xfs_dqmarker_t   q_lists;       /* list ptrs, q_flags (marker) */
  70         xfs_dqhash_t    *q_hash;        /* the hashchain header */
  71         struct xfs_mount*q_mount;       /* filesystem this relates to */
  72         struct xfs_trans*q_transp;      /* trans this belongs to currently */
  73         uint             q_nrefs;       /* # active refs from inodes */
  74         xfs_daddr_t      q_blkno;       /* blkno of dquot buffer */
  75         int              q_bufoffset;   /* off of dq in buffer (# dquots) */
  76         xfs_fileoff_t    q_fileoffset;  /* offset in quotas file */
  77
  78         struct xfs_dquot*q_gdquot;      /* group dquot, hint only */
  79         xfs_disk_dquot_t q_core;        /* actual usage & quotas */
  80         xfs_dq_logitem_t q_logitem;     /* dquot log item */
  81         xfs_qcnt_t       q_res_bcount;  /* total regular nblks used+reserved */
  82         xfs_qcnt_t       q_res_icount;  /* total inos allocd+reserved */
  83         xfs_qcnt_t       q_res_rtbcount;/* total realtime blks used+reserved */
  84         struct mutex     q_qlock;       /* quota lock */
  85         struct completion q_flush;      /* flush completion queue */
  86         atomic_t          q_pincount;   /* dquot pin count */
  87         wait_queue_head_t q_pinwait;    /* dquot pinning wait queue */
  88 } xfs_dquot_t;
  89
  90
  91 #define dq_flnext       q_lists.dqm_flnext
  92 #define dq_flprev       q_lists.dqm_flprev
  93 #define dq_mplist       q_lists.dqm_mplist
  94 #define dq_hashlist     q_lists.dqm_hashlist
  95 #define dq_flags        q_lists.dqm_flags
  96
  97 /*
  98  * Lock hierarchy for q_qlock:
  99  *      XFS_QLOCK_NORMAL is the implicit default,
 100  *      XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
 101  */
 102 enum {
 103         XFS_QLOCK_NORMAL = 0,
 104         XFS_QLOCK_NESTED,
 105 };
 106
 107 #define XFS_DQHOLD(dqp)         ((dqp)->q_nrefs++)
 108
 109 /*
 110  * Manage the q_flush completion queue embedded in the dquot.  This completion
 111  * queue synchronizes processes attempting to flush the in-core dquot back to
 112  * disk.
 113  */
 114 static inline void xfs_dqflock(xfs_dquot_t *dqp)
 115 {
 116         wait_for_completion(&dqp->q_flush);
 117 }
 118
 119 static inline int xfs_dqflock_nowait(xfs_dquot_t *dqp)
 120 {
 121         return try_wait_for_completion(&dqp->q_flush);
 122 }
 123
 124 static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
 125 {
 126         complete(&dqp->q_flush);
 127 }
 128
 129 #define XFS_DQ_IS_LOCKED(dqp)   (mutex_is_locked(&((dqp)->q_qlock)))
 130 #define XFS_DQ_IS_ON_FREELIST(dqp)  ((dqp)->dq_flnext != (dqp))
 131 #define XFS_DQ_IS_DIRTY(dqp)    ((dqp)->dq_flags & XFS_DQ_DIRTY)
 132 #define XFS_QM_ISUDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_USER)
 133 #define XFS_QM_ISPDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_PROJ)
 134 #define XFS_QM_ISGDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_GROUP)
 135 #define XFS_DQ_TO_QINF(dqp)     ((dqp)->q_mount->m_quotainfo)
 136 #define XFS_DQ_TO_QIP(dqp)      (XFS_QM_ISUDQ(dqp) ? \
 137                                  XFS_DQ_TO_QINF(dqp)->qi_uquotaip : \
 138                                  XFS_DQ_TO_QINF(dqp)->qi_gquotaip)
 139
 140 #define XFS_IS_THIS_QUOTA_OFF(d) (! (XFS_QM_ISUDQ(d) ? \
 141                                      (XFS_IS_UQUOTA_ON((d)->q_mount)) : \
 142                                      (XFS_IS_OQUOTA_ON((d)->q_mount))))
 143
 144 #ifdef QUOTADEBUG
 145 extern void             xfs_qm_dqprint(xfs_dquot_t *);
 146 #else
 147 #define xfs_qm_dqprint(a)
 148 #endif
 149
 150 extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
 151 extern int              xfs_qm_dqflush(xfs_dquot_t *, uint);
 152 extern int              xfs_qm_dqpurge(xfs_dquot_t *);
 153 extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
 154 extern int              xfs_qm_dqlock_nowait(xfs_dquot_t *);
 155 extern void             xfs_qm_dqflock_pushbuf_wait(xfs_dquot_t *dqp);
 156 extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
 157                                         xfs_disk_dquot_t *);
 158 extern void             xfs_qm_adjust_dqlimits(xfs_mount_t *,
 159                                         xfs_disk_dquot_t *);
 160 extern int              xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
 161                                         xfs_dqid_t, uint, uint, xfs_dquot_t **);
 162 extern void             xfs_qm_dqput(xfs_dquot_t *);
 163 extern void             xfs_dqlock(xfs_dquot_t *);
 164 extern void             xfs_dqlock2(xfs_dquot_t *, xfs_dquot_t *);
 165 extern void             xfs_dqunlock(xfs_dquot_t *);
 166 extern void             xfs_dqunlock_nonotify(xfs_dquot_t *);
 167
 168 #endif /* __XFS_DQUOT_H__ */