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)->hash \
36 +(offsetp)->LowPart) / cm_data.buf_blockSize) \
37 % cm_data.buf_hashSize)
40 #define BUF_FILEHASH(fidp) ((fidp)->hash % cm_data.buf_hashSize)
42 /* backup over pointer to the buffer */
43 #define BUF_OVERTOBUF(op) ((cm_buf_t *)(((char *)op) - ((long)(&((cm_buf_t *)0)->over))))
45 #define CM_BUF_MAGIC ('B' | 'U' <<8 | 'F'<<16 | 'F'<<24)
47 #define CM_BUF_VERSION_BAD 0xFFFFFFFFFFFFFFFF
49 /* represents a single buffer */
50 typedef struct cm_buf {
51 osi_queue_t q; /* queue of all zero-refcount buffers */
53 struct cm_buf *allp; /* next in all list */
54 struct cm_buf *hashp; /* hash bucket pointer */
55 struct cm_buf *fileHashp; /* file hash bucket pointer */
56 struct cm_buf *fileHashBackp; /* file hash bucket back pointer */
58 * The file hash chain is doubly linked, since
59 * these chains can get rather long. The
60 * regular hash chain is only singly linked,
61 * since the chains should be short if the
62 * hash function is good and if there are
63 * enough buckets for the size of the cache.
65 struct cm_buf *dirtyp; /* next in the dirty list */
66 osi_mutex_t mx; /* mutex protecting structure except refcount */
67 afs_int32 refCount; /* reference count (buf_globalLock) */
68 long idCounter; /* counter for softrefs; bumped at each recycle */
69 long dirtyCounter; /* bumped at each dirty->clean transition */
70 osi_hyper_t offset; /* offset */
71 cm_fid_t fid; /* file ID */
72 afs_uint32 flags; /* flags we're using */
73 char *datap; /* data in this buffer */
74 unsigned long error; /* last error code, if CM_BUF_ERROR is set */
75 cm_user_t *userp; /* user who wrote to the buffer last */
77 /* fields added for the CM; locked by scp->mx */
78 afs_uint64 dataVersion; /* data version of this page */
79 afs_uint32 cmFlags; /* flags for cm */
82 afs_uint32 waitCount; /* number of threads waiting */
83 afs_uint32 waitRequests; /* num of thread wait requests */
85 afs_uint32 dirty_offset; /* offset from beginning of buffer containing dirty bytes */
86 afs_uint32 dirty_length; /* number of dirty bytes within the buffer */
89 cm_diskcache_t *dcp; /* diskcache structure */
90 #endif /* DISKCACHE95 */
92 cm_scache_t *scp; /* for debugging, the scache object belonging to */
93 /* the fid at the time of fid assignment. */
99 /* values for cmFlags */
100 #define CM_BUF_CMFETCHING 1 /* fetching this buffer */
101 #define CM_BUF_CMSTORING 2 /* storing this buffer */
102 #define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
103 #define CM_BUF_CMWRITING 8 /* writing to this buffer */
104 /* waiting is done based on scp->flags. Removing bits from cmFlags
105 should be followed by waking the scp. */
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 from 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 extern long buf_Init(int newFile, cm_buf_ops_t *, afs_uint64 nbuffers);
136 extern void buf_Shutdown(void);
138 extern long buf_CountFreeList(void);
140 extern void buf_Release(cm_buf_t *);
142 extern void buf_Hold(cm_buf_t *);
144 extern void buf_WaitIO(cm_scache_t *, cm_buf_t *);
146 extern void buf_ReleaseLocked(cm_buf_t *, afs_uint32);
148 extern void buf_HoldLocked(cm_buf_t *);
150 extern cm_buf_t *buf_FindLocked(struct cm_scache *, osi_hyper_t *);
152 extern cm_buf_t *buf_Find(struct cm_scache *, osi_hyper_t *);
154 extern long buf_GetNewLocked(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
156 extern long buf_Get(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
158 extern long buf_GetNew(struct cm_scache *, osi_hyper_t *, cm_buf_t **);
160 extern long buf_CleanAsyncLocked(cm_buf_t *, cm_req_t *);
162 extern long buf_CleanAsync(cm_buf_t *, cm_req_t *);
164 extern void buf_CleanWait(cm_scache_t *, cm_buf_t *, afs_uint32 locked);
166 extern void buf_SetDirty(cm_buf_t *, afs_uint32 offset, afs_uint32 length);
168 extern long buf_CleanAndReset(void);
170 extern void buf_ReserveBuffers(afs_uint64);
172 extern int buf_TryReserveBuffers(afs_uint64);
174 extern void buf_UnreserveBuffers(afs_uint64);
177 extern void buf_ValidateBufQueues(void);
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(afs_uint64 nbuffers);
193 extern long buf_ValidateBuffers(void);
195 extern void buf_ForceTrace(BOOL flush);
197 extern long buf_DirtyBuffersExist(cm_fid_t * fidp);
199 extern long buf_CleanDirtyBuffers(cm_scache_t *scp);
201 extern long buf_ForceDataVersion(cm_scache_t * scp, afs_uint64 fromVersion, afs_uint64 toVersion);
204 #define CM_BUF_EXISTS 1 /* buffer exists, and shouldn't */
205 #endif /* _BUF_H__ENV_ */