2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
10 /* Copyright (C) 1994 Cazamar Systems, Inc. */
13 #define _BUF_H__ENV_ 1
17 #include "cm_diskcache.h"
18 #endif /* DISKCACHE95 */
20 /* default # of buffers if not changed */
21 #define CM_BUF_BUFFERS 100
22 extern long buf_nbuffers;
24 /* orig # of buffers */
25 extern long buf_nOrigBuffers;
27 /* default buffer size */
28 #define CM_BUF_SIZE 4096
29 extern long buf_bufferSize;
31 /* default hash size */
32 #define CM_BUF_HASHSIZE 1024
33 extern long buf_hashSize;
36 #define CM_BUF_CACHETYPE_FILE 1
37 #define CM_BUF_CACHETYPE_VIRTUAL 2
38 extern int buf_cacheType;
40 /* force it to be signed so that mod comes out positive or 0 */
41 #define BUF_HASH(fidp,offsetp) ((((fidp)->vnode+((fidp)->unique << 5) \
42 +(fidp)->volume+(fidp)->cell \
43 +((offsetp)->LowPart / buf_bufferSize)) \
48 #define BUF_FILEHASH(fidp) ((((fidp)->vnode+((fidp)->unique << 5) \
49 +(fidp)->volume+(fidp)->cell) \
53 /* backup over pointer to the buffer */
54 #define BUF_OVERTOBUF(op) ((cm_buf_t *)(((char *)op) - ((long)(&((cm_buf_t *)0)->over))))
56 /* pretend we have logs, too */
57 typedef char cm_log_t;
59 /* represents a single buffer */
60 typedef struct cm_buf {
61 osi_queue_t q; /* queue of all zero-refcount buffers */
62 struct cm_buf *hashp; /* hash bucket pointer */
63 struct cm_buf *fileHashp; /* file hash bucket pointer */
64 struct cm_buf *fileHashBackp; /* file hash bucket back pointer */
66 * The file hash chain is doubly linked, since
67 * these chains can get rather long. The
68 * regular hash chain is only singly linked,
69 * since the chains should be short if the
70 * hash function is good and if there are
71 * enough buckets for the size of the cache.
73 struct cm_buf *allp; /* next in all list */
74 osi_mutex_t mx; /* mutex protecting structure except refcount */
75 int refCount; /* reference count (buf_globalLock) */
76 long idCounter; /* counter for softrefs; bumped at each recycle */
77 long dirtyCounter; /* bumped at each dirty->clean transition */
79 struct cm_log *logp; /* log for this buffer, if any */
80 osi_hyper_t lsn; /* lsn to force to (last LSN changing this buffer) */
82 osi_hyper_t offset; /* offset */
83 cm_fid_t fid; /* file ID */
84 long flags; /* flags we're using */
85 long size; /* size in bytes of this buffer */
86 char *datap; /* data in this buffer */
87 unsigned long error; /* last error code, if CM_BUF_ERROR is set */
88 struct cm_user *userp; /* user who wrote to the buffer last */
90 OVERLAPPED over; /* overlapped structure for I/O */
93 /* fields added for the CM; locked by scp->mx */
94 long dataVersion; /* data version of this page */
95 long cmFlags; /* flags for cm */
97 cm_diskcache_t *dcp; /* diskcache structure */
98 #endif /* DISKCACHE95 */
101 /* values for cmFlags */
102 #define CM_BUF_CMFETCHING 1 /* fetching this buffer */
103 #define CM_BUF_CMSTORING 2 /* storing this buffer */
104 #define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
105 /* waiting is done based on scp->flags */
107 /* represents soft reference which is OK to lose on a recycle */
108 typedef struct cm_softRef {
109 cm_buf_t *bufp; /* buffer (may get reused) */
110 long counter; /* counter of changes to identity */
113 #define CM_BUF_READING 1 /* now reading buffer to the disk */
114 #define CM_BUF_WRITING 2 /* now writing buffer to the disk */
115 #define CM_BUF_INHASH 4 /* in the hash table */
116 #define CM_BUF_DIRTY 8 /* buffer is dirty */
117 #define CM_BUF_INLRU 0x10 /* in lru queue */
118 #define CM_BUF_ERROR 0x20 /* something went wrong on delayed write */
119 #define CM_BUF_WAITING 0x40 /* someone's waiting for a flag to change */
120 #define CM_BUF_EVWAIT 0x80 /* someone's waiting for the buffer event */
121 #define CM_BUF_EOF 0x100 /* read 0 bytes; used for detecting EOF */
123 typedef struct cm_buf_ops {
124 long (*Writep)(void *, osi_hyper_t *, long, long, struct cm_user *,
126 long (*Readp)(cm_buf_t *, long, long *, struct cm_user *);
127 long (*Stabilizep)(void *, struct cm_user *, struct cm_req *);
128 long (*Unstabilizep)(void *, struct cm_user *);
132 extern osi_rwlock_t buf_globalLock;
134 /* buffer free list */
135 extern cm_buf_t *buf_freeListp;
137 /* pointer to hash table */
138 extern cm_buf_t **buf_hashTablepp;
140 /* another hash table */
141 extern cm_buf_t **buf_fileHashTablepp;
143 extern long buf_Init(cm_buf_ops_t *);
145 extern long buf_CountFreeList(void);
147 extern void buf_Release(cm_buf_t *);
149 extern void buf_Hold(cm_buf_t *);
151 extern void buf_WaitIO(cm_buf_t *);
153 extern void buf_LockedRelease(cm_buf_t *);
155 extern cm_buf_t *buf_LockedFind(struct cm_scache *, osi_hyper_t *);
157 extern cm_buf_t *buf_Find(struct cm_scache *, osi_hyper_t *);
160 extern HANDLE buf_GetFileHandle(long);
163 extern void buf_LockedCleanAsync(cm_buf_t *, cm_req_t *);
165 extern long buf_GetNewLocked(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
167 extern long buf_Get(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
169 extern long buf_GetNew(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
171 extern void buf_CleanAsync(cm_buf_t *, cm_req_t *);
173 extern void buf_CleanWait(cm_buf_t *);
175 extern void buf_SetDirty(cm_buf_t *);
177 extern long buf_CleanAndReset(void);
179 extern void buf_ReserveBuffers(long);
181 extern int buf_TryReserveBuffers(long);
183 extern void buf_UnreserveBuffers(long);
185 extern osi_log_t *buf_logp;
187 extern long buf_Truncate(struct cm_scache *scp, cm_user_t *userp,
188 cm_req_t *reqp, osi_hyper_t *sizep);
190 extern long buf_CleanVnode(struct cm_scache *scp, cm_user_t *userp,
193 extern long buf_FlushCleanPages(cm_scache_t *scp, cm_user_t *userp,
196 extern long buf_SetNBuffers(long nbuffers);
199 #define CM_BUF_EXISTS 1 /* buffer exists, and shouldn't */
200 #define CM_ERROR_BASEBUF 0x33333333
201 #define CM_ERROR_TOOFEWBUFS (CM_ERROR_BASEBUF+0)
202 #define CM_ERROR_TOOMANYBUFS (CM_ERROR_BASEBUF+1)
203 #endif /* _BUF_H__ENV_ */