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;
35 /* force it to be signed so that mod comes out positive or 0 */
36 #define BUF_HASH(fidp,offsetp) ((((fidp)->vnode+((fidp)->unique << 5) \
37 +(fidp)->volume+(fidp)->cell \
38 +((offsetp)->LowPart / buf_bufferSize)) \
43 #define BUF_FILEHASH(fidp) ((((fidp)->vnode+((fidp)->unique << 5) \
44 +(fidp)->volume+(fidp)->cell) \
48 /* backup over pointer to the buffer */
49 #define BUF_OVERTOBUF(op) ((cm_buf_t *)(((char *)op) - ((long)(&((cm_buf_t *)0)->over))))
51 /* pretend we have logs, too */
52 typedef char cm_log_t;
54 /* represents a single buffer */
55 typedef struct cm_buf {
56 osi_queue_t q; /* queue of all zero-refcount buffers */
57 struct cm_buf *hashp; /* hash bucket pointer */
58 struct cm_buf *fileHashp; /* file hash bucket pointer */
59 struct cm_buf *fileHashBackp; /* file hash bucket back pointer */
61 * The file hash chain is doubly linked, since
62 * these chains can get rather long. The
63 * regular hash chain is only singly linked,
64 * since the chains should be short if the
65 * hash function is good and if there are
66 * enough buckets for the size of the cache.
68 struct cm_buf *allp; /* next in all list */
69 osi_mutex_t mx; /* mutex protecting structure except refcount */
70 int refCount; /* reference count */
71 long idCounter; /* counter for softrefs; bumped at each recycle */
72 long dirtyCounter; /* bumped at each dirty->clean transition */
74 struct cm_log *logp; /* log for this buffer, if any */
75 osi_hyper_t lsn; /* lsn to force to (last LSN changing this buffer) */
77 osi_hyper_t offset; /* offset */
78 cm_fid_t fid; /* file ID */
79 long flags; /* flags we're using */
80 long size; /* size in bytes of this buffer */
81 char *datap; /* data in this buffer */
82 unsigned long error; /* last error code, if CM_BUF_ERROR is set */
83 struct cm_user *userp; /* user who wrote to the buffer last */
85 OVERLAPPED over; /* overlapped structure for I/O */
88 /* fields added for the CM; locked by scp->mx */
89 long dataVersion; /* data version of this page */
90 long cmFlags; /* flags for cm */
92 cm_diskcache_t *dcp; /* diskcache structure */
93 #endif /* DISKCACHE95 */
96 /* values for cmFlags */
97 #define CM_BUF_CMFETCHING 1 /* fetching this buffer */
98 #define CM_BUF_CMSTORING 2 /* storing this buffer */
99 #define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
100 /* waiting is done based on scp->flags */
102 /* represents soft reference which is OK to lose on a recycle */
103 typedef struct cm_softRef {
104 cm_buf_t *bufp; /* buffer (may get reused) */
105 long counter; /* counter of changes to identity */
108 #define CM_BUF_READING 1 /* now reading buffer to the disk */
109 #define CM_BUF_WRITING 2 /* now writing buffer to the disk */
110 #define CM_BUF_INHASH 4 /* in the hash table */
111 #define CM_BUF_DIRTY 8 /* buffer is dirty */
112 #define CM_BUF_INLRU 0x10 /* in lru queue */
113 #define CM_BUF_ERROR 0x20 /* something went wrong on delayed write */
114 #define CM_BUF_WAITING 0x40 /* someone's waiting for a flag to change */
115 #define CM_BUF_EVWAIT 0x80 /* someone's waiting for the buffer event */
116 #define CM_BUF_EOF 0x100 /* read 0 bytes; used for detecting EOF */
118 typedef struct cm_buf_ops {
119 long (*Writep)(void *, osi_hyper_t *, long, long, struct cm_user *,
121 long (*Readp)(cm_buf_t *, long, long *, struct cm_user *);
122 long (*Stabilizep)(void *, struct cm_user *, struct cm_req *);
123 long (*Unstabilizep)(void *, struct cm_user *);
127 extern osi_rwlock_t buf_globalLock;
129 /* buffer free list */
130 extern cm_buf_t *buf_freeListp;
132 /* pointer to hash table */
133 extern cm_buf_t **buf_hashTablepp;
135 /* another hash table */
136 extern cm_buf_t **buf_fileHashTablepp;
138 extern long buf_Init(cm_buf_ops_t *);
140 extern long buf_CountFreeList(void);
142 extern void buf_Release(cm_buf_t *);
144 extern void buf_Hold(cm_buf_t *);
146 extern void buf_WaitIO(cm_buf_t *);
148 extern void buf_LockedRelease(cm_buf_t *);
150 extern cm_buf_t *buf_LockedFind(struct cm_scache *, osi_hyper_t *);
152 extern cm_buf_t *buf_Find(struct cm_scache *, osi_hyper_t *);
155 extern HANDLE buf_GetFileHandle(long);
158 extern void buf_LockedCleanAsync(cm_buf_t *, cm_req_t *);
160 extern long buf_GetNewLocked(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
162 extern long buf_Get(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
164 extern long buf_GetNew(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
166 extern void buf_CleanAsync(cm_buf_t *, cm_req_t *);
168 extern void buf_CleanWait(cm_buf_t *);
170 extern void buf_SetDirty(cm_buf_t *);
172 extern long buf_CleanAndReset(void);
174 extern void buf_ReserveBuffers(long);
176 extern int buf_TryReserveBuffers(long);
178 extern void buf_UnreserveBuffers(long);
180 extern osi_log_t *buf_logp;
182 extern long buf_Truncate(struct cm_scache *scp, cm_user_t *userp,
183 cm_req_t *reqp, osi_hyper_t *sizep);
185 extern long buf_CleanVnode(struct cm_scache *scp, cm_user_t *userp,
188 extern long buf_FlushCleanPages(cm_scache_t *scp, cm_user_t *userp,
191 extern long buf_SetNBuffers(long nbuffers);
194 #define CM_BUF_EXISTS 1 /* buffer exists, and shouldn't */
195 #define CM_ERROR_BASEBUF 0x33333333
196 #define CM_ERROR_TOOFEWBUFS (CM_ERROR_BASEBUF+0)
197 #define CM_ERROR_TOOMANYBUFS (CM_ERROR_BASEBUF+1)
198 #endif /* _BUF_H__ENV_ */