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
23 /* default buffer size */
24 #define CM_BUF_BLOCKSIZE CM_CONFIGDEFAULT_BLOCKSIZE
26 /* default hash size */
27 #define CM_BUF_HASHSIZE 1024
30 #define CM_BUF_CACHETYPE_FILE 1
31 #define CM_BUF_CACHETYPE_VIRTUAL 2
32 extern int buf_cacheType;
34 /* force it to be signed so that mod comes out positive or 0 */
35 #define BUF_HASH(fidp,offsetp) ((((fidp)->vnode+((fidp)->unique << 5) \
36 +(fidp)->volume+(fidp)->cell \
37 +((offsetp)->LowPart / cm_data.buf_blockSize)) \
39 % cm_data.buf_hashSize)
42 #define BUF_FILEHASH(fidp) ((((fidp)->vnode+((fidp)->unique << 5) \
43 +(fidp)->volume+(fidp)->cell) \
45 % cm_data.buf_hashSize)
47 /* backup over pointer to the buffer */
48 #define BUF_OVERTOBUF(op) ((cm_buf_t *)(((char *)op) - ((long)(&((cm_buf_t *)0)->over))))
50 #define CM_BUF_MAGIC ('B' | 'U' <<8 | 'F'<<16 | 'F'<<24)
52 /* represents a single buffer */
53 typedef struct cm_buf {
54 osi_queue_t q; /* queue of all zero-refcount buffers */
56 struct cm_buf *allp; /* next in all list */
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 *dirtyp; /* next in the dirty list */
69 osi_mutex_t mx; /* mutex protecting structure except refcount */
70 unsigned long refCount; /* reference count (buf_globalLock) */
71 long idCounter; /* counter for softrefs; bumped at each recycle */
72 long dirtyCounter; /* bumped at each dirty->clean transition */
73 osi_hyper_t offset; /* offset */
74 cm_fid_t fid; /* file ID */
76 cm_scache_t *scp; /* for debugging, the scache object belonging to */
77 /* the fid at the time of fid assignment. */
79 long flags; /* flags we're using */
80 char *datap; /* data in this buffer */
81 unsigned long error; /* last error code, if CM_BUF_ERROR is set */
82 cm_user_t *userp; /* user who wrote to the buffer last */
83 OVERLAPPED over; /* overlapped structure for I/O */
85 /* fields added for the CM; locked by scp->mx */
86 long dataVersion; /* data version of this page */
87 long cmFlags; /* flags for cm */
89 cm_diskcache_t *dcp; /* diskcache structure */
90 #endif /* DISKCACHE95 */
93 afs_uint32 waitCount; /* number of threads waiting */
94 afs_uint32 waitRequests; /* num of thread wait requests */
97 /* values for cmFlags */
98 #define CM_BUF_CMFETCHING 1 /* fetching this buffer */
99 #define CM_BUF_CMSTORING 2 /* storing this buffer */
100 #define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
101 /* waiting is done based on scp->flags */
103 /* represents soft reference which is OK to lose on a recycle */
104 typedef struct cm_softRef {
105 cm_buf_t *bufp; /* buffer (may get reused) */
106 long counter; /* counter of changes to identity */
109 #define CM_BUF_READING 1 /* now reading buffer from the disk */
110 #define CM_BUF_WRITING 2 /* now writing buffer to the disk */
111 #define CM_BUF_INHASH 4 /* in the hash table */
112 #define CM_BUF_DIRTY 8 /* buffer is dirty */
113 #define CM_BUF_INLRU 0x10 /* in lru queue */
114 #define CM_BUF_ERROR 0x20 /* something went wrong on delayed write */
115 #define CM_BUF_WAITING 0x40 /* someone's waiting for a flag to change */
116 #define CM_BUF_EVWAIT 0x80 /* someone's waiting for the buffer event */
117 #define CM_BUF_EOF 0x100 /* read 0 bytes; used for detecting EOF */
119 typedef struct cm_buf_ops {
120 long (*Writep)(void *, osi_hyper_t *, long, long, struct cm_user *,
122 long (*Readp)(cm_buf_t *, long, long *, struct cm_user *);
123 long (*Stabilizep)(void *, struct cm_user *, struct cm_req *);
124 long (*Unstabilizep)(void *, struct cm_user *);
128 extern osi_rwlock_t buf_globalLock;
130 extern long buf_Init(int newFile, cm_buf_ops_t *, afs_uint64 nbuffers);
132 extern void buf_Shutdown(void);
134 extern long buf_CountFreeList(void);
136 extern void buf_Release(cm_buf_t *);
138 extern void buf_Hold(cm_buf_t *);
140 extern void buf_WaitIO(cm_scache_t *, cm_buf_t *);
142 extern void buf_ReleaseLocked(cm_buf_t *);
144 extern void buf_HoldLocked(cm_buf_t *);
146 extern cm_buf_t *buf_FindLocked(struct cm_scache *, osi_hyper_t *);
148 extern cm_buf_t *buf_Find(struct cm_scache *, osi_hyper_t *);
150 extern long buf_GetNewLocked(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
152 extern long buf_Get(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
154 extern long buf_GetNew(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
156 extern long buf_CleanAsyncLocked(cm_buf_t *, cm_req_t *);
158 extern long buf_CleanAsync(cm_buf_t *, cm_req_t *);
160 extern void buf_CleanWait(cm_scache_t *, cm_buf_t *);
162 extern void buf_SetDirty(cm_buf_t *);
164 extern long buf_CleanAndReset(void);
166 extern void buf_ReserveBuffers(afs_uint64);
168 extern int buf_TryReserveBuffers(afs_uint64);
170 extern void buf_UnreserveBuffers(afs_uint64);
173 extern void buf_ValidateBufQueues(void);
176 extern osi_log_t *buf_logp;
178 extern long buf_Truncate(struct cm_scache *scp, cm_user_t *userp,
179 cm_req_t *reqp, osi_hyper_t *sizep);
181 extern long buf_CleanVnode(struct cm_scache *scp, cm_user_t *userp,
184 extern long buf_FlushCleanPages(cm_scache_t *scp, cm_user_t *userp,
187 extern long buf_SetNBuffers(afs_uint64 nbuffers);
189 extern long buf_ValidateBuffers(void);
191 extern void buf_ForceTrace(BOOL flush);
193 extern long buf_DirtyBuffersExist(cm_fid_t * fidp);
195 extern long buf_CleanDirtyBuffers(cm_scache_t *scp);
198 #define CM_BUF_EXISTS 1 /* buffer exists, and shouldn't */
199 #endif /* _BUF_H__ENV_ */