Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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         mutex_t           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         mutex_t          q_qlock;       /* quota lock */
 85         sema_t           q_flock;       /* flush lock */
 86         uint             q_pincount;    /* pin count for this dquot */
 87         sv_t             q_pinwait;     /* sync var for pinning */
 88 #ifdef XFS_DQUOT_TRACE
 89         struct ktrace   *q_trace;       /* trace header structure */
 90 #endif
 91 } xfs_dquot_t;
 92 
 93 
 94 #define dq_flnext       q_lists.dqm_flnext
 95 #define dq_flprev       q_lists.dqm_flprev
 96 #define dq_mplist       q_lists.dqm_mplist
 97 #define dq_hashlist     q_lists.dqm_hashlist
 98 #define dq_flags        q_lists.dqm_flags
 99 
100 #define XFS_DQHOLD(dqp)         ((dqp)->q_nrefs++)
101 
102 #ifdef DEBUG
103 static inline int
104 XFS_DQ_IS_LOCKED(xfs_dquot_t *dqp)
105 {
106         if (mutex_trylock(&dqp->q_qlock)) {
107                 mutex_unlock(&dqp->q_qlock);
108                 return 0;
109         }
110         return 1;
111 }
112 #endif
113 
114 
115 /*
116  * The following three routines simply manage the q_flock
117  * semaphore embedded in the dquot.  This semaphore synchronizes
118  * processes attempting to flush the in-core dquot back to disk.
119  */
120 #define xfs_dqflock(dqp)         { psema(&((dqp)->q_flock), PINOD | PRECALC);\
121                                    (dqp)->dq_flags |= XFS_DQ_FLOCKED; }
122 #define xfs_dqfunlock(dqp)       { ASSERT(issemalocked(&((dqp)->q_flock))); \
123                                    vsema(&((dqp)->q_flock)); \
124                                    (dqp)->dq_flags &= ~(XFS_DQ_FLOCKED); }
125 
126 #define XFS_DQ_IS_FLUSH_LOCKED(dqp) (issemalocked(&((dqp)->q_flock)))
127 #define XFS_DQ_IS_ON_FREELIST(dqp)  ((dqp)->dq_flnext != (dqp))
128 #define XFS_DQ_IS_DIRTY(dqp)    ((dqp)->dq_flags & XFS_DQ_DIRTY)
129 #define XFS_QM_ISUDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_USER)
130 #define XFS_QM_ISPDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_PROJ)
131 #define XFS_QM_ISGDQ(dqp)       ((dqp)->dq_flags & XFS_DQ_GROUP)
132 #define XFS_DQ_TO_QINF(dqp)     ((dqp)->q_mount->m_quotainfo)
133 #define XFS_DQ_TO_QIP(dqp)      (XFS_QM_ISUDQ(dqp) ? \
134                                  XFS_DQ_TO_QINF(dqp)->qi_uquotaip : \
135                                  XFS_DQ_TO_QINF(dqp)->qi_gquotaip)
136 
137 #define XFS_IS_THIS_QUOTA_OFF(d) (! (XFS_QM_ISUDQ(d) ? \
138                                      (XFS_IS_UQUOTA_ON((d)->q_mount)) : \
139                                      (XFS_IS_OQUOTA_ON((d)->q_mount))))
140 
141 #ifdef XFS_DQUOT_TRACE
142 /*
143  * Dquot Tracing stuff.
144  */
145 #define DQUOT_TRACE_SIZE        64
146 #define DQUOT_KTRACE_ENTRY      1
147 
148 extern void             __xfs_dqtrace_entry(xfs_dquot_t *dqp, char *func,
149                                             void *, xfs_inode_t *);
150 #define xfs_dqtrace_entry_ino(a,b,ip) \
151                 __xfs_dqtrace_entry((a), (b), (void*)__return_address, (ip))
152 #define xfs_dqtrace_entry(a,b) \
153                 __xfs_dqtrace_entry((a), (b), (void*)__return_address, NULL)
154 #else
155 #define xfs_dqtrace_entry(a,b)
156 #define xfs_dqtrace_entry_ino(a,b,ip)
157 #endif
158 
159 #ifdef QUOTADEBUG
160 extern void             xfs_qm_dqprint(xfs_dquot_t *);
161 #else
162 #define xfs_qm_dqprint(a)
163 #endif
164 
165 extern void             xfs_qm_dqdestroy(xfs_dquot_t *);
166 extern int              xfs_qm_dqflush(xfs_dquot_t *, uint);
167 extern int              xfs_qm_dqpurge(xfs_dquot_t *, uint);
168 extern void             xfs_qm_dqunpin_wait(xfs_dquot_t *);
169 extern int              xfs_qm_dqlock_nowait(xfs_dquot_t *);
170 extern int              xfs_qm_dqflock_nowait(xfs_dquot_t *);
171 extern void             xfs_qm_dqflock_pushbuf_wait(xfs_dquot_t *dqp);
172 extern void             xfs_qm_adjust_dqtimers(xfs_mount_t *,
173                                         xfs_disk_dquot_t *);
174 extern void             xfs_qm_adjust_dqlimits(xfs_mount_t *,
175                                         xfs_disk_dquot_t *);
176 extern int              xfs_qm_dqget(xfs_mount_t *, xfs_inode_t *,
177                                         xfs_dqid_t, uint, uint, xfs_dquot_t **);
178 extern void             xfs_qm_dqput(xfs_dquot_t *);
179 extern void             xfs_qm_dqrele(xfs_dquot_t *);
180 extern void             xfs_dqlock(xfs_dquot_t *);
181 extern void             xfs_dqlock2(xfs_dquot_t *, xfs_dquot_t *);
182 extern void             xfs_dqunlock(xfs_dquot_t *);
183 extern void             xfs_dqunlock_nonotify(xfs_dquot_t *);
184 
185 #endif /* __XFS_DQUOT_H__ */
186 
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