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root/fs/xfs/quota/xfs_dquot.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. XFS_DQ_IS_LOCKED
  2. xfs_dqflock
  3. xfs_dqflock_nowait
  4. xfs_dqfunlock

/*
 * 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.
 */

/*
 * The hash chain headers (hash buckets)
 */
typedef struct xfs_dqhash {
        struct xfs_dquot *qh_next;
        mutex_t           qh_lock;
        uint              qh_version;   /* ever increasing version */
        uint              qh_nelems;    /* number of dquots on the list */
} xfs_dqhash_t;

typedef struct xfs_dqlink {
        struct xfs_dquot  *ql_next;     /* forward link */
        struct xfs_dquot **ql_prevp;    /* pointer to prev ql_next */
} xfs_dqlink_t;

struct xfs_mount;
struct xfs_trans;

/*
 * This is the marker which is designed to occupy the first few
 * bytes of the xfs_dquot_t structure. Even inside this, the freelist pointers
 * must come first.
 * This serves as the marker ("sentinel") when we have to restart list
 * iterations because of locking considerations.
 */
typedef struct xfs_dqmarker {
        struct xfs_dquot*dqm_flnext;    /* link to freelist: must be first */
        struct xfs_dquot*dqm_flprev;
        xfs_dqlink_t     dqm_mplist;    /* link to mount's list of dquots */
        xfs_dqlink_t     dqm_hashlist;  /* link to the hash chain */
        uint             dqm_flags;     /* various flags (XFS_DQ_*) */
} xfs_dqmarker_t;

/*
 * The incore dquot structure
 */
typedef struct xfs_dquot {
        xfs_dqmarker_t   q_lists;       /* list ptrs, q_flags (marker) */
        xfs_dqhash_t    *q_hash;        /* the hashchain header */
        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 */
        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 */
        mutex_t          q_qlock;       /* quota lock */
        struct completion q_flush;      /* flush completion queue */
        uint             q_pincount;    /* pin count for this dquot */
        sv_t             q_pinwait;     /* sync var for pinning */
#ifdef XFS_DQUOT_TRACE
        struct ktrace   *q_trace;       /* trace header structure */
#endif
} xfs_dquot_t;


#define dq_flnext       q_lists.dqm_flnext
#define dq_flprev       q_lists.dqm_flprev
#define dq_mplist       q_lists.dqm_mplist
#define dq_hashlist     q_lists.dqm_hashlist
#define dq_flags        q_lists.dqm_flags

#define XFS_DQHOLD(dqp)         ((dqp)->q_nrefs++)

#ifdef DEBUG
static inline int
XFS_DQ_IS_LOCKED(xfs_dquot_t *dqp)
{
        if (mutex_trylock(&dqp->q_qlock)) {
                mutex_unlock(&dqp->q_qlock);
                return 0;
        }
        return 1;
}
#endif


/*
 * 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);
}

#define XFS_DQ_IS_ON_FREELIST(dqp)  ((dqp)->dq_flnext != (dqp))
#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)
#define XFS_DQ_TO_QINF(dqp)     ((dqp)->q_mount->m_quotainfo)
#define XFS_DQ_TO_QIP(dqp)      (XFS_QM_ISUDQ(dqp) ? \
                                 XFS_DQ_TO_QINF(dqp)->qi_uquotaip : \
                                 XFS_DQ_TO_QINF(dqp)->qi_gquotaip)

#define XFS_IS_THIS_QUOTA_OFF(d) (! (XFS_QM_ISUDQ(d) ? \
                                     (XFS_IS_UQUOTA_ON((d)->q_mount)) : \
                                     (XFS_IS_OQUOTA_ON((d)->q_mount))))

#ifdef XFS_DQUOT_TRACE
/*
 * Dquot Tracing stuff.
 */
#define DQUOT_TRACE_SIZE        64
#define DQUOT_KTRACE_ENTRY      1

extern void             __xfs_dqtrace_entry(xfs_dquot_t *dqp, char *func,
                                            void *, xfs_inode_t *);
#define xfs_dqtrace_entry_ino(a,b,ip) \
                __xfs_dqtrace_entry((a), (b), (void*)__return_address, (ip))
#define xfs_dqtrace_entry(a,b) \
                __xfs_dqtrace_entry((a), (b), (void*)__return_address, NULL)
#else
#define xfs_dqtrace_entry(a,b)
#define xfs_dqtrace_entry_ino(a,b,ip)
#endif

#ifdef QUOTADEBUG
extern void             xfs_qm_dqprint(xfs_dquot_t *);
#else
#define xfs_qm_dqprint(a)
#endif

extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
extern int              xfs_qm_dqflush(xfs_dquot_t *, uint);
extern int              xfs_qm_dqpurge(xfs_dquot_t *);
extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
extern int              xfs_qm_dqlock_nowait(xfs_dquot_t *);
extern void             xfs_qm_dqflock_pushbuf_wait(xfs_dquot_t *dqp);
extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
                                        xfs_disk_dquot_t *);
extern void             xfs_qm_adjust_dqlimits(xfs_mount_t *,
                                        xfs_disk_dquot_t *);
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_qm_dqrele(xfs_dquot_t *);
extern void             xfs_dqlock(xfs_dquot_t *);
extern void             xfs_dqlock2(xfs_dquot_t *, xfs_dquot_t *);
extern void             xfs_dqunlock(xfs_dquot_t *);
extern void             xfs_dqunlock_nonotify(xfs_dquot_t *);

#endif /* __XFS_DQUOT_H__ */

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