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 */
75 long flags; /* flags we're using */
76 char *datap; /* data in this buffer */
77 unsigned long error; /* last error code, if CM_BUF_ERROR is set */
78 cm_user_t *userp; /* user who wrote to the buffer last */
80 /* fields added for the CM; locked by scp->mx */
81 long dataVersion; /* data version of this page */
82 long cmFlags; /* flags for cm */
85 afs_uint32 waitCount; /* number of threads waiting */
86 afs_uint32 waitRequests; /* num of thread wait requests */
88 afs_uint32 dirty_offset; /* offset from beginning of buffer containing dirty bytes */
89 afs_uint32 dirty_length; /* number of dirty bytes within the buffer */
92 cm_diskcache_t *dcp; /* diskcache structure */
93 #endif /* DISKCACHE95 */
95 cm_scache_t *scp; /* for debugging, the scache object belonging to */
96 /* the fid at the time of fid assignment. */
102 /* values for cmFlags */
103 #define CM_BUF_CMFETCHING 1 /* fetching this buffer */
104 #define CM_BUF_CMSTORING 2 /* storing this buffer */
105 #define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
106 #define CM_BUF_CMWRITING 8 /* writing to this buffer */
107 /* waiting is done based on scp->flags. Removing bits from cmFlags
108 should be followed by waking the scp. */
110 /* represents soft reference which is OK to lose on a recycle */
111 typedef struct cm_softRef {
112 cm_buf_t *bufp; /* buffer (may get reused) */
113 long counter; /* counter of changes to identity */
116 #define CM_BUF_READING 1 /* now reading buffer from the disk */
117 #define CM_BUF_WRITING 2 /* now writing buffer to the disk */
118 #define CM_BUF_INHASH 4 /* in the hash table */
119 #define CM_BUF_DIRTY 8 /* buffer is dirty */
120 #define CM_BUF_INLRU 0x10 /* in lru queue */
121 #define CM_BUF_ERROR 0x20 /* something went wrong on delayed write */
122 #define CM_BUF_WAITING 0x40 /* someone's waiting for a flag to change */
123 #define CM_BUF_EVWAIT 0x80 /* someone's waiting for the buffer event */
124 #define CM_BUF_EOF 0x100 /* read 0 bytes; used for detecting EOF */
126 typedef struct cm_buf_ops {
127 long (*Writep)(void *, osi_hyper_t *, long, long, struct cm_user *,
129 long (*Readp)(cm_buf_t *, long, long *, struct cm_user *);
130 long (*Stabilizep)(void *, struct cm_user *, struct cm_req *);
131 long (*Unstabilizep)(void *, struct cm_user *);
135 extern osi_rwlock_t buf_globalLock;
137 extern long buf_Init(int newFile, cm_buf_ops_t *, afs_uint64 nbuffers);
139 extern void buf_Shutdown(void);
141 extern long buf_CountFreeList(void);
143 extern void buf_Release(cm_buf_t *);
145 extern void buf_Hold(cm_buf_t *);
147 extern void buf_WaitIO(cm_scache_t *, cm_buf_t *);
149 extern void buf_ReleaseLocked(cm_buf_t *);
151 extern void buf_HoldLocked(cm_buf_t *);
153 extern cm_buf_t *buf_FindLocked(struct cm_scache *, osi_hyper_t *);
155 extern cm_buf_t *buf_Find(struct cm_scache *, osi_hyper_t *);
157 extern long buf_GetNewLocked(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
159 extern long buf_Get(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
161 extern long buf_GetNew(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
163 extern long buf_CleanAsyncLocked(cm_buf_t *, cm_req_t *);
165 extern long buf_CleanAsync(cm_buf_t *, cm_req_t *);
167 extern void buf_CleanWait(cm_scache_t *, cm_buf_t *);
169 extern void buf_SetDirty(cm_buf_t *, afs_uint32 offset, afs_uint32 length);
171 extern long buf_CleanAndReset(void);
173 extern void buf_ReserveBuffers(afs_uint64);
175 extern int buf_TryReserveBuffers(afs_uint64);
177 extern void buf_UnreserveBuffers(afs_uint64);
180 extern void buf_ValidateBufQueues(void);
183 extern osi_log_t *buf_logp;
185 extern long buf_Truncate(struct cm_scache *scp, cm_user_t *userp,
186 cm_req_t *reqp, osi_hyper_t *sizep);
188 extern long buf_CleanVnode(struct cm_scache *scp, cm_user_t *userp,
191 extern long buf_FlushCleanPages(cm_scache_t *scp, cm_user_t *userp,
194 extern long buf_SetNBuffers(afs_uint64 nbuffers);
196 extern long buf_ValidateBuffers(void);
198 extern void buf_ForceTrace(BOOL flush);
200 extern long buf_DirtyBuffersExist(cm_fid_t * fidp);
202 extern long buf_CleanDirtyBuffers(cm_scache_t *scp);
204 extern long buf_ForceDataVersion(cm_scache_t * scp, afs_uint32 fromVersion, afs_uint32 toVersion);
207 #define CM_BUF_EXISTS 1 /* buffer exists, and shouldn't */
208 #endif /* _BUF_H__ENV_ */