LXR linux/fs/xfs/xfs

   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
  32struct xfs_mount;
  33struct xfs_trans;
  34
  35/*
  36 * The incore dquot structure
  37 */
  38typedef struct xfs_dquot {
  39        uint             dq_flags;      /* various flags (XFS_DQ_*) */
  40        struct list_head q_lru;         /* global free list of dquots */
  41        struct xfs_mount*q_mount;       /* filesystem this relates to */
  42        struct xfs_trans*q_transp;      /* trans this belongs to currently */
  43        uint             q_nrefs;       /* # active refs from inodes */
  44        xfs_daddr_t      q_blkno;       /* blkno of dquot buffer */
  45        int              q_bufoffset;   /* off of dq in buffer (# dquots) */
  46        xfs_fileoff_t    q_fileoffset;  /* offset in quotas file */
  47
  48        struct xfs_dquot*q_gdquot;      /* group dquot, hint only */
  49        xfs_disk_dquot_t q_core;        /* actual usage & quotas */
  50        xfs_dq_logitem_t q_logitem;     /* dquot log item */
  51        xfs_qcnt_t       q_res_bcount;  /* total regular nblks used+reserved */
  52        xfs_qcnt_t       q_res_icount;  /* total inos allocd+reserved */
  53        xfs_qcnt_t       q_res_rtbcount;/* total realtime blks used+reserved */
  54        struct mutex     q_qlock;       /* quota lock */
  55        struct completion q_flush;      /* flush completion queue */
  56        atomic_t          q_pincount;   /* dquot pin count */
  57        wait_queue_head_t q_pinwait;    /* dquot pinning wait queue */
  58} xfs_dquot_t;
  59
  60/*
  61 * Lock hierarchy for q_qlock:
  62 *      XFS_QLOCK_NORMAL is the implicit default,
  63 *      XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
  64 */
  65enum {
  66        XFS_QLOCK_NORMAL = 0,
  67        XFS_QLOCK_NESTED,
  68};
  69
  70/*
  71 * Manage the q_flush completion queue embedded in the dquot.  This completion
  72 * queue synchronizes processes attempting to flush the in-core dquot back to
  73 * disk.
  74 */
  75static inline void xfs_dqflock(xfs_dquot_t *dqp)
  76{
  77        wait_for_completion(&dqp->q_flush);
  78}
  79
  80static inline int xfs_dqflock_nowait(xfs_dquot_t *dqp)
  81{
  82        return try_wait_for_completion(&dqp->q_flush);
  83}
  84
  85static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
  86{
  87        complete(&dqp->q_flush);
  88}
  89
  90static inline int xfs_dqlock_nowait(struct xfs_dquot *dqp)
  91{
  92        return mutex_trylock(&dqp->q_qlock);
  93}
  94
  95static inline void xfs_dqlock(struct xfs_dquot *dqp)
  96{
  97        mutex_lock(&dqp->q_qlock);
  98}
  99
 100static inline void xfs_dqunlock(struct xfs_dquot *dqp)
 101{
 102        mutex_unlock(&dqp->q_qlock);
 103}
 104
 105static inline int xfs_this_quota_on(struct xfs_mount *mp, int type)
 106{
 107        switch (type & XFS_DQ_ALLTYPES) {
 108        case XFS_DQ_USER:
 109                return XFS_IS_UQUOTA_ON(mp);
 110        case XFS_DQ_GROUP:
 111        case XFS_DQ_PROJ:
 112                return XFS_IS_OQUOTA_ON(mp);
 113        default:
 114                return 0;
 115        }
 116}
 117
 118static inline xfs_dquot_t *xfs_inode_dquot(struct xfs_inode *ip, int type)
 119{
 120        switch (type & XFS_DQ_ALLTYPES) {
 121        case XFS_DQ_USER:
 122                return ip->i_udquot;
 123        case XFS_DQ_GROUP:
 124        case XFS_DQ_PROJ:
 125                return ip->i_gdquot;
 126        default:
 127                return NULL;
 128        }
 129}
 130
 131#define XFS_DQ_IS_LOCKED(dqp)   (mutex_is_locked(&((dqp)->q_qlock)))
 132#define XFS_DQ_IS_DIRTY(dqp)    ((dqp)->dq_flags & XFS_DQ_DIRTY)
 133#define XFS_QM_ISUDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_USER)
 134#define XFS_QM_ISPDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_PROJ)
 135#define XFS_QM_ISGDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_GROUP)
 136#define XFS_DQ_TO_QINF(dqp)     ((dqp)->q_mount->m_quotainfo)
 137#define XFS_DQ_TO_QIP(dqp)      (XFS_QM_ISUDQ(dqp) ? \
 138                                 XFS_DQ_TO_QINF(dqp)->qi_uquotaip : \
 139                                 XFS_DQ_TO_QINF(dqp)->qi_gquotaip)
 140
 141extern int              xfs_qm_dqread(struct xfs_mount *, xfs_dqid_t, uint,
 142                                        uint, struct xfs_dquot  **);
 143extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
 144extern int              xfs_qm_dqflush(struct xfs_dquot *, struct xfs_buf **);
 145extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
 146extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
 147                                        xfs_disk_dquot_t *);
 148extern void             xfs_qm_adjust_dqlimits(xfs_mount_t *,
 149                                        xfs_disk_dquot_t *);
 150extern int              xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
 151                                        xfs_dqid_t, uint, uint, xfs_dquot_t **);
 152extern void             xfs_qm_dqput(xfs_dquot_t *);
 153
 154extern void             xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
 155
 156static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
 157{
 158        xfs_dqlock(dqp);
 159        dqp->q_nrefs++;
 160        xfs_dqunlock(dqp);
 161        return dqp;
 162}
 163
 164#endif /* __XFS_DQUOT_H__ */
 165