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
  35enum {
  36        XFS_QLOWSP_1_PCNT = 0,
  37        XFS_QLOWSP_3_PCNT,
  38        XFS_QLOWSP_5_PCNT,
  39        XFS_QLOWSP_MAX
  40};
  41
  42/*
  43 * The incore dquot structure
  44 */
  45typedef struct xfs_dquot {
  46        uint             dq_flags;      /* various flags (XFS_DQ_*) */
  47        struct list_head q_lru;         /* global free list of dquots */
  48        struct xfs_mount*q_mount;       /* filesystem this relates to */
  49        struct xfs_trans*q_transp;      /* trans this belongs to currently */
  50        uint             q_nrefs;       /* # active refs from inodes */
  51        xfs_daddr_t      q_blkno;       /* blkno of dquot buffer */
  52        int              q_bufoffset;   /* off of dq in buffer (# dquots) */
  53        xfs_fileoff_t    q_fileoffset;  /* offset in quotas file */
  54
  55        xfs_disk_dquot_t q_core;        /* actual usage & quotas */
  56        xfs_dq_logitem_t q_logitem;     /* dquot log item */
  57        xfs_qcnt_t       q_res_bcount;  /* total regular nblks used+reserved */
  58        xfs_qcnt_t       q_res_icount;  /* total inos allocd+reserved */
  59        xfs_qcnt_t       q_res_rtbcount;/* total realtime blks used+reserved */
  60        xfs_qcnt_t       q_prealloc_lo_wmark;/* prealloc throttle wmark */
  61        xfs_qcnt_t       q_prealloc_hi_wmark;/* prealloc disabled wmark */
  62        int64_t          q_low_space[XFS_QLOWSP_MAX];
  63        struct mutex     q_qlock;       /* quota lock */
  64        struct completion q_flush;      /* flush completion queue */
  65        atomic_t          q_pincount;   /* dquot pin count */
  66        wait_queue_head_t q_pinwait;    /* dquot pinning wait queue */
  67} xfs_dquot_t;
  68
  69/*
  70 * Lock hierarchy for q_qlock:
  71 *      XFS_QLOCK_NORMAL is the implicit default,
  72 *      XFS_QLOCK_NESTED is the dquot with the higher id in xfs_dqlock2
  73 */
  74enum {
  75        XFS_QLOCK_NORMAL = 0,
  76        XFS_QLOCK_NESTED,
  77};
  78
  79/*
  80 * Manage the q_flush completion queue embedded in the dquot.  This completion
  81 * queue synchronizes processes attempting to flush the in-core dquot back to
  82 * disk.
  83 */
  84static inline void xfs_dqflock(xfs_dquot_t *dqp)
  85{
  86        wait_for_completion(&dqp->q_flush);
  87}
  88
  89static inline bool xfs_dqflock_nowait(xfs_dquot_t *dqp)
  90{
  91        return try_wait_for_completion(&dqp->q_flush);
  92}
  93
  94static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
  95{
  96        complete(&dqp->q_flush);
  97}
  98
  99static inline int xfs_dqlock_nowait(struct xfs_dquot *dqp)
 100{
 101        return mutex_trylock(&dqp->q_qlock);
 102}
 103
 104static inline void xfs_dqlock(struct xfs_dquot *dqp)
 105{
 106        mutex_lock(&dqp->q_qlock);
 107}
 108
 109static inline void xfs_dqunlock(struct xfs_dquot *dqp)
 110{
 111        mutex_unlock(&dqp->q_qlock);
 112}
 113
 114static inline int xfs_this_quota_on(struct xfs_mount *mp, int type)
 115{
 116        switch (type & XFS_DQ_ALLTYPES) {
 117        case XFS_DQ_USER:
 118                return XFS_IS_UQUOTA_ON(mp);
 119        case XFS_DQ_GROUP:
 120                return XFS_IS_GQUOTA_ON(mp);
 121        case XFS_DQ_PROJ:
 122                return XFS_IS_PQUOTA_ON(mp);
 123        default:
 124                return 0;
 125        }
 126}
 127
 128static inline xfs_dquot_t *xfs_inode_dquot(struct xfs_inode *ip, int type)
 129{
 130        switch (type & XFS_DQ_ALLTYPES) {
 131        case XFS_DQ_USER:
 132                return ip->i_udquot;
 133        case XFS_DQ_GROUP:
 134                return ip->i_gdquot;
 135        case XFS_DQ_PROJ:
 136                return ip->i_pdquot;
 137        default:
 138                return NULL;
 139        }
 140}
 141
 142/*
 143 * Check whether a dquot is under low free space conditions. We assume the quota
 144 * is enabled and enforced.
 145 */
 146static inline bool xfs_dquot_lowsp(struct xfs_dquot *dqp)
 147{
 148        int64_t freesp;
 149
 150        freesp = be64_to_cpu(dqp->q_core.d_blk_hardlimit) - dqp->q_res_bcount;
 151        if (freesp < dqp->q_low_space[XFS_QLOWSP_1_PCNT])
 152                return true;
 153
 154        return false;
 155}
 156
 157#define XFS_DQ_IS_LOCKED(dqp)   (mutex_is_locked(&((dqp)->q_qlock)))
 158#define XFS_DQ_IS_DIRTY(dqp)    ((dqp)->dq_flags & XFS_DQ_DIRTY)
 159#define XFS_QM_ISUDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_USER)
 160#define XFS_QM_ISPDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_PROJ)
 161#define XFS_QM_ISGDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_GROUP)
 162
 163extern int              xfs_qm_dqread(struct xfs_mount *, xfs_dqid_t, uint,
 164                                        uint, struct xfs_dquot  **);
 165extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
 166extern int              xfs_qm_dqflush(struct xfs_dquot *, struct xfs_buf **);
 167extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
 168extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
 169                                        xfs_disk_dquot_t *);
 170extern void             xfs_qm_adjust_dqlimits(struct xfs_mount *,
 171                                               struct xfs_dquot *);
 172extern int              xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
 173                                        xfs_dqid_t, uint, uint, xfs_dquot_t **);
 174extern void             xfs_qm_dqput(xfs_dquot_t *);
 175
 176extern void             xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
 177
 178extern void             xfs_dquot_set_prealloc_limits(struct xfs_dquot *);
 179
 180static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
 181{
 182        xfs_dqlock(dqp);
 183        dqp->q_nrefs++;
 184        xfs_dqunlock(dqp);
 185        return dqp;
 186}
 187
 188#endif /* __XFS_DQUOT_H__ */
 189