2 056fe1ba 2003-11-23 devnull * Memory-only VtBlock cache.
4 056fe1ba 2003-11-23 devnull * The cached Venti blocks are in the hash chains.
5 056fe1ba 2003-11-23 devnull * The cached local blocks are only in the blocks array.
6 056fe1ba 2003-11-23 devnull * The free blocks are in the heap, which is supposed to
7 056fe1ba 2003-11-23 devnull * be indexed by second-to-last use but actually
8 056fe1ba 2003-11-23 devnull * appears to be last use.
11 056fe1ba 2003-11-23 devnull #include <u.h>
12 056fe1ba 2003-11-23 devnull #include <libc.h>
13 056fe1ba 2003-11-23 devnull #include <venti.h>
15 7252036f 2005-11-02 devnull int vtcachenread;
16 7252036f 2005-11-02 devnull int vtcachencopy;
17 7252036f 2005-11-02 devnull int vtcachenwrite;
20 056fe1ba 2003-11-23 devnull BioLocal = 1,
21 056fe1ba 2003-11-23 devnull BioVenti,
22 056fe1ba 2003-11-23 devnull BioReading,
23 056fe1ba 2003-11-23 devnull BioWriting,
24 056fe1ba 2003-11-23 devnull BioEmpty,
25 056fe1ba 2003-11-23 devnull BioVentiError,
28 056fe1ba 2003-11-23 devnull BadHeap = ~0,
30 056fe1ba 2003-11-23 devnull struct VtCache
32 056fe1ba 2003-11-23 devnull QLock lk;
33 056fe1ba 2003-11-23 devnull VtConn *z;
34 056fe1ba 2003-11-23 devnull u32int blocksize;
35 056fe1ba 2003-11-23 devnull u32int now; /* ticks for usage time stamps */
36 056fe1ba 2003-11-23 devnull VtBlock **hash; /* hash table for finding addresses */
37 056fe1ba 2003-11-23 devnull int nhash;
38 056fe1ba 2003-11-23 devnull VtBlock **heap; /* heap for finding victims */
39 056fe1ba 2003-11-23 devnull int nheap;
40 056fe1ba 2003-11-23 devnull VtBlock *block; /* all allocated blocks */
41 056fe1ba 2003-11-23 devnull int nblock;
42 056fe1ba 2003-11-23 devnull uchar *mem; /* memory for all blocks and data */
43 a1882dc1 2004-06-17 devnull int (*write)(VtConn*, uchar[VtScoreSize], uint, uchar*, int);
46 056fe1ba 2003-11-23 devnull static void cachecheck(VtCache*);
49 e87f5d7c 2005-07-13 devnull vtcachealloc(VtConn *z, int blocksize, ulong nblock)
51 056fe1ba 2003-11-23 devnull uchar *p;
52 056fe1ba 2003-11-23 devnull VtCache *c;
54 056fe1ba 2003-11-23 devnull VtBlock *b;
56 056fe1ba 2003-11-23 devnull c = vtmallocz(sizeof(VtCache));
58 056fe1ba 2003-11-23 devnull c->z = z;
59 056fe1ba 2003-11-23 devnull c->blocksize = (blocksize + 127) & ~127;
60 056fe1ba 2003-11-23 devnull c->nblock = nblock;
61 056fe1ba 2003-11-23 devnull c->nhash = nblock;
62 056fe1ba 2003-11-23 devnull c->hash = vtmallocz(nblock*sizeof(VtBlock*));
63 056fe1ba 2003-11-23 devnull c->heap = vtmallocz(nblock*sizeof(VtBlock*));
64 056fe1ba 2003-11-23 devnull c->block = vtmallocz(nblock*sizeof(VtBlock));
65 056fe1ba 2003-11-23 devnull c->mem = vtmallocz(nblock*c->blocksize);
66 a1882dc1 2004-06-17 devnull c->write = vtwrite;
68 056fe1ba 2003-11-23 devnull p = c->mem;
69 056fe1ba 2003-11-23 devnull for(i=0; i<nblock; i++){
70 056fe1ba 2003-11-23 devnull b = &c->block[i];
71 056fe1ba 2003-11-23 devnull b->addr = NilBlock;
72 056fe1ba 2003-11-23 devnull b->c = c;
73 056fe1ba 2003-11-23 devnull b->data = p;
74 056fe1ba 2003-11-23 devnull b->heap = i;
75 056fe1ba 2003-11-23 devnull c->heap[i] = b;
76 056fe1ba 2003-11-23 devnull p += c->blocksize;
78 056fe1ba 2003-11-23 devnull c->nheap = nblock;
79 056fe1ba 2003-11-23 devnull cachecheck(c);
80 056fe1ba 2003-11-23 devnull return c;
84 a1882dc1 2004-06-17 devnull * BUG This is here so that vbackup can override it and do some
85 a1882dc1 2004-06-17 devnull * pipelining of writes. Arguably vtwrite or vtwritepacket or the
86 a1882dc1 2004-06-17 devnull * cache itself should be providing this functionality.
89 a1882dc1 2004-06-17 devnull vtcachesetwrite(VtCache *c, int (*write)(VtConn*, uchar[VtScoreSize], uint, uchar*, int))
91 a1882dc1 2004-06-17 devnull if(write == nil)
92 a1882dc1 2004-06-17 devnull write = vtwrite;
93 a1882dc1 2004-06-17 devnull c->write = write;
97 056fe1ba 2003-11-23 devnull vtcachefree(VtCache *c)
101 056fe1ba 2003-11-23 devnull qlock(&c->lk);
103 056fe1ba 2003-11-23 devnull cachecheck(c);
104 056fe1ba 2003-11-23 devnull for(i=0; i<c->nblock; i++)
105 056fe1ba 2003-11-23 devnull assert(c->block[i].ref == 0);
107 056fe1ba 2003-11-23 devnull vtfree(c->hash);
108 056fe1ba 2003-11-23 devnull vtfree(c->heap);
109 056fe1ba 2003-11-23 devnull vtfree(c->block);
110 056fe1ba 2003-11-23 devnull vtfree(c->mem);
111 056fe1ba 2003-11-23 devnull vtfree(c);
114 056fe1ba 2003-11-23 devnull static void
115 056fe1ba 2003-11-23 devnull vtcachedump(VtCache *c)
118 056fe1ba 2003-11-23 devnull VtBlock *b;
120 056fe1ba 2003-11-23 devnull for(i=0; i<c->nblock; i++){
121 056fe1ba 2003-11-23 devnull b = &c->block[i];
122 056fe1ba 2003-11-23 devnull print("cache block %d: type %d score %V iostate %d addr %d ref %d nlock %d\n",
123 056fe1ba 2003-11-23 devnull i, b->type, b->score, b->iostate, b->addr, b->ref, b->nlock);
127 056fe1ba 2003-11-23 devnull static void
128 056fe1ba 2003-11-23 devnull cachecheck(VtCache *c)
130 056fe1ba 2003-11-23 devnull u32int size, now;
131 056fe1ba 2003-11-23 devnull int i, k, refed;
132 056fe1ba 2003-11-23 devnull VtBlock *b;
134 056fe1ba 2003-11-23 devnull size = c->blocksize;
135 056fe1ba 2003-11-23 devnull now = c->now;
137 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nheap; i++){
138 056fe1ba 2003-11-23 devnull if(c->heap[i]->heap != i)
139 056fe1ba 2003-11-23 devnull sysfatal("mis-heaped at %d: %d", i, c->heap[i]->heap);
140 056fe1ba 2003-11-23 devnull if(i > 0 && c->heap[(i - 1) >> 1]->used - now > c->heap[i]->used - now)
141 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
142 056fe1ba 2003-11-23 devnull k = (i << 1) + 1;
143 056fe1ba 2003-11-23 devnull if(k < c->nheap && c->heap[i]->used - now > c->heap[k]->used - now)
144 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
146 056fe1ba 2003-11-23 devnull if(k < c->nheap && c->heap[i]->used - now > c->heap[k]->used - now)
147 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
150 056fe1ba 2003-11-23 devnull refed = 0;
151 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nblock; i++){
152 056fe1ba 2003-11-23 devnull b = &c->block[i];
153 056fe1ba 2003-11-23 devnull if(b->data != &c->mem[i * size])
154 056fe1ba 2003-11-23 devnull sysfatal("mis-blocked at %d", i);
155 056fe1ba 2003-11-23 devnull if(b->ref && b->heap == BadHeap)
156 056fe1ba 2003-11-23 devnull refed++;
157 056fe1ba 2003-11-23 devnull else if(b->addr != NilBlock)
158 056fe1ba 2003-11-23 devnull refed++;
160 056fe1ba 2003-11-23 devnull if(c->nheap + refed != c->nblock){
161 056fe1ba 2003-11-23 devnull fprint(2, "cachecheck: nheap %d refed %d nblocks %d\n", c->nheap, refed, c->nblock);
162 056fe1ba 2003-11-23 devnull //vtcachedump(c);
164 056fe1ba 2003-11-23 devnull assert(c->nheap + refed == c->nblock);
165 056fe1ba 2003-11-23 devnull refed = 0;
166 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nblock; i++){
167 056fe1ba 2003-11-23 devnull b = &c->block[i];
168 056fe1ba 2003-11-23 devnull if(b->ref){
169 056fe1ba 2003-11-23 devnull if(1)fprint(2, "a=%ud %V ref=%d\n", b->addr, b->score, b->ref);
170 056fe1ba 2003-11-23 devnull refed++;
173 056fe1ba 2003-11-23 devnull if(refed > 0)fprint(2, "cachecheck: in used %d\n", refed);
176 056fe1ba 2003-11-23 devnull static int
177 056fe1ba 2003-11-23 devnull upheap(int i, VtBlock *b)
179 056fe1ba 2003-11-23 devnull VtBlock *bb;
180 056fe1ba 2003-11-23 devnull u32int now;
182 056fe1ba 2003-11-23 devnull VtCache *c;
184 056fe1ba 2003-11-23 devnull c = b->c;
185 056fe1ba 2003-11-23 devnull now = c->now;
186 056fe1ba 2003-11-23 devnull for(; i != 0; i = p){
187 056fe1ba 2003-11-23 devnull p = (i - 1) >> 1;
188 056fe1ba 2003-11-23 devnull bb = c->heap[p];
189 056fe1ba 2003-11-23 devnull if(b->used - now >= bb->used - now)
191 056fe1ba 2003-11-23 devnull c->heap[i] = bb;
192 056fe1ba 2003-11-23 devnull bb->heap = i;
194 056fe1ba 2003-11-23 devnull c->heap[i] = b;
195 056fe1ba 2003-11-23 devnull b->heap = i;
197 056fe1ba 2003-11-23 devnull return i;
200 056fe1ba 2003-11-23 devnull static int
201 056fe1ba 2003-11-23 devnull downheap(int i, VtBlock *b)
203 056fe1ba 2003-11-23 devnull VtBlock *bb;
204 056fe1ba 2003-11-23 devnull u32int now;
206 056fe1ba 2003-11-23 devnull VtCache *c;
208 056fe1ba 2003-11-23 devnull c = b->c;
209 056fe1ba 2003-11-23 devnull now = c->now;
210 056fe1ba 2003-11-23 devnull for(; ; i = k){
211 056fe1ba 2003-11-23 devnull k = (i << 1) + 1;
212 056fe1ba 2003-11-23 devnull if(k >= c->nheap)
214 056fe1ba 2003-11-23 devnull if(k + 1 < c->nheap && c->heap[k]->used - now > c->heap[k + 1]->used - now)
216 056fe1ba 2003-11-23 devnull bb = c->heap[k];
217 056fe1ba 2003-11-23 devnull if(b->used - now <= bb->used - now)
219 056fe1ba 2003-11-23 devnull c->heap[i] = bb;
220 056fe1ba 2003-11-23 devnull bb->heap = i;
222 056fe1ba 2003-11-23 devnull c->heap[i] = b;
223 056fe1ba 2003-11-23 devnull b->heap = i;
224 056fe1ba 2003-11-23 devnull return i;
228 056fe1ba 2003-11-23 devnull * Delete a block from the heap.
229 056fe1ba 2003-11-23 devnull * Called with c->lk held.
231 056fe1ba 2003-11-23 devnull static void
232 056fe1ba 2003-11-23 devnull heapdel(VtBlock *b)
234 056fe1ba 2003-11-23 devnull int i, si;
235 056fe1ba 2003-11-23 devnull VtCache *c;
237 056fe1ba 2003-11-23 devnull c = b->c;
239 056fe1ba 2003-11-23 devnull si = b->heap;
240 056fe1ba 2003-11-23 devnull if(si == BadHeap)
242 056fe1ba 2003-11-23 devnull b->heap = BadHeap;
243 056fe1ba 2003-11-23 devnull c->nheap--;
244 056fe1ba 2003-11-23 devnull if(si == c->nheap)
246 056fe1ba 2003-11-23 devnull b = c->heap[c->nheap];
247 056fe1ba 2003-11-23 devnull i = upheap(si, b);
248 056fe1ba 2003-11-23 devnull if(i == si)
249 056fe1ba 2003-11-23 devnull downheap(i, b);
253 056fe1ba 2003-11-23 devnull * Insert a block into the heap.
254 056fe1ba 2003-11-23 devnull * Called with c->lk held.
256 056fe1ba 2003-11-23 devnull static void
257 056fe1ba 2003-11-23 devnull heapins(VtBlock *b)
259 056fe1ba 2003-11-23 devnull assert(b->heap == BadHeap);
260 056fe1ba 2003-11-23 devnull upheap(b->c->nheap++, b);
264 056fe1ba 2003-11-23 devnull * locate the vtBlock with the oldest second to last use.
265 056fe1ba 2003-11-23 devnull * remove it from the heap, and fix up the heap.
267 056fe1ba 2003-11-23 devnull /* called with c->lk held */
268 056fe1ba 2003-11-23 devnull static VtBlock*
269 056fe1ba 2003-11-23 devnull vtcachebumpblock(VtCache *c)
271 056fe1ba 2003-11-23 devnull VtBlock *b;
274 056fe1ba 2003-11-23 devnull * locate the vtBlock with the oldest second to last use.
275 056fe1ba 2003-11-23 devnull * remove it from the heap, and fix up the heap.
277 056fe1ba 2003-11-23 devnull if(c->nheap == 0){
278 056fe1ba 2003-11-23 devnull vtcachedump(c);
279 7cb74894 2004-06-17 devnull fprint(2, "vtcachebumpblock: no free blocks in vtCache");
280 7cb74894 2004-06-17 devnull abort();
282 056fe1ba 2003-11-23 devnull b = c->heap[0];
283 056fe1ba 2003-11-23 devnull heapdel(b);
285 056fe1ba 2003-11-23 devnull assert(b->heap == BadHeap);
286 056fe1ba 2003-11-23 devnull assert(b->ref == 0);
289 056fe1ba 2003-11-23 devnull * unchain the vtBlock from hash chain if any
291 056fe1ba 2003-11-23 devnull if(b->prev){
292 056fe1ba 2003-11-23 devnull *(b->prev) = b->next;
293 056fe1ba 2003-11-23 devnull if(b->next)
294 056fe1ba 2003-11-23 devnull b->next->prev = b->prev;
295 056fe1ba 2003-11-23 devnull b->prev = nil;
299 056fe1ba 2003-11-23 devnull if(0)fprint(2, "droping %x:%V\n", b->addr, b->score);
300 056fe1ba 2003-11-23 devnull /* set vtBlock to a reasonable state */
301 056fe1ba 2003-11-23 devnull b->ref = 1;
302 056fe1ba 2003-11-23 devnull b->iostate = BioEmpty;
303 056fe1ba 2003-11-23 devnull return b;
307 056fe1ba 2003-11-23 devnull * fetch a local block from the memory cache.
308 056fe1ba 2003-11-23 devnull * if it's not there, load it, bumping some other Block.
309 056fe1ba 2003-11-23 devnull * if we're out of free blocks, we're screwed.
311 056fe1ba 2003-11-23 devnull VtBlock*
312 056fe1ba 2003-11-23 devnull vtcachelocal(VtCache *c, u32int addr, int type)
314 056fe1ba 2003-11-23 devnull VtBlock *b;
316 23fb2edb 2005-07-24 devnull if(addr == 0)
317 23fb2edb 2005-07-24 devnull sysfatal("vtcachelocal: asked for nonexistent block 0");
318 23fb2edb 2005-07-24 devnull if(addr > c->nblock)
319 23fb2edb 2005-07-24 devnull sysfatal("vtcachelocal: asked for block #%ud; only %d blocks",
320 056fe1ba 2003-11-23 devnull addr, c->nblock);
322 23fb2edb 2005-07-24 devnull b = &c->block[addr-1];
323 056fe1ba 2003-11-23 devnull if(b->addr == NilBlock || b->iostate != BioLocal)
324 056fe1ba 2003-11-23 devnull sysfatal("vtcachelocal: block is not local");
326 056fe1ba 2003-11-23 devnull if(b->type != type)
327 056fe1ba 2003-11-23 devnull sysfatal("vtcachelocal: block has wrong type %d != %d", b->type, type);
329 056fe1ba 2003-11-23 devnull qlock(&c->lk);
330 056fe1ba 2003-11-23 devnull b->ref++;
331 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
333 056fe1ba 2003-11-23 devnull qlock(&b->lk);
334 056fe1ba 2003-11-23 devnull b->nlock = 1;
335 056fe1ba 2003-11-23 devnull return b;
338 056fe1ba 2003-11-23 devnull VtBlock*
339 056fe1ba 2003-11-23 devnull vtcacheallocblock(VtCache *c, int type)
341 056fe1ba 2003-11-23 devnull VtBlock *b;
343 056fe1ba 2003-11-23 devnull qlock(&c->lk);
344 056fe1ba 2003-11-23 devnull b = vtcachebumpblock(c);
345 056fe1ba 2003-11-23 devnull b->iostate = BioLocal;
346 056fe1ba 2003-11-23 devnull b->type = type;
347 23fb2edb 2005-07-24 devnull b->addr = (b - c->block)+1;
348 056fe1ba 2003-11-23 devnull vtzeroextend(type, b->data, 0, c->blocksize);
349 056fe1ba 2003-11-23 devnull vtlocaltoglobal(b->addr, b->score);
350 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
352 056fe1ba 2003-11-23 devnull qlock(&b->lk);
353 056fe1ba 2003-11-23 devnull b->nlock = 1;
355 056fe1ba 2003-11-23 devnull return b;
359 056fe1ba 2003-11-23 devnull * fetch a global (Venti) block from the memory cache.
360 056fe1ba 2003-11-23 devnull * if it's not there, load it, bumping some other block.
362 056fe1ba 2003-11-23 devnull VtBlock*
363 056fe1ba 2003-11-23 devnull vtcacheglobal(VtCache *c, uchar score[VtScoreSize], int type)
365 056fe1ba 2003-11-23 devnull VtBlock *b;
366 056fe1ba 2003-11-23 devnull ulong h;
368 056fe1ba 2003-11-23 devnull u32int addr;
370 056fe1ba 2003-11-23 devnull addr = vtglobaltolocal(score);
371 056fe1ba 2003-11-23 devnull if(addr != NilBlock)
372 056fe1ba 2003-11-23 devnull return vtcachelocal(c, addr, type);
374 056fe1ba 2003-11-23 devnull h = (u32int)(score[0]|(score[1]<<8)|(score[2]<<16)|(score[3]<<24)) % c->nhash;
377 056fe1ba 2003-11-23 devnull * look for the block in the cache
379 056fe1ba 2003-11-23 devnull qlock(&c->lk);
380 056fe1ba 2003-11-23 devnull for(b = c->hash[h]; b != nil; b = b->next){
381 056fe1ba 2003-11-23 devnull if(b->addr != NilBlock || memcmp(b->score, score, VtScoreSize) != 0 || b->type != type)
382 056fe1ba 2003-11-23 devnull continue;
383 056fe1ba 2003-11-23 devnull heapdel(b);
384 056fe1ba 2003-11-23 devnull b->ref++;
385 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
386 056fe1ba 2003-11-23 devnull qlock(&b->lk);
387 056fe1ba 2003-11-23 devnull b->nlock = 1;
388 0c148046 2004-06-16 devnull if(b->iostate == BioVentiError){
389 eacc220a 2004-06-17 devnull if(chattyventi)
390 eacc220a 2004-06-17 devnull fprint(2, "cached read error for %V\n", score);
391 0c148046 2004-06-16 devnull werrstr("venti i/o error");
392 0c148046 2004-06-16 devnull vtblockput(b);
393 0c148046 2004-06-16 devnull return nil;
395 056fe1ba 2003-11-23 devnull return b;
399 056fe1ba 2003-11-23 devnull * not found
401 056fe1ba 2003-11-23 devnull b = vtcachebumpblock(c);
402 056fe1ba 2003-11-23 devnull b->addr = NilBlock;
403 056fe1ba 2003-11-23 devnull b->type = type;
404 056fe1ba 2003-11-23 devnull memmove(b->score, score, VtScoreSize);
405 056fe1ba 2003-11-23 devnull /* chain onto correct hash */
406 056fe1ba 2003-11-23 devnull b->next = c->hash[h];
407 056fe1ba 2003-11-23 devnull c->hash[h] = b;
408 056fe1ba 2003-11-23 devnull if(b->next != nil)
409 056fe1ba 2003-11-23 devnull b->next->prev = &b->next;
410 056fe1ba 2003-11-23 devnull b->prev = &c->hash[h];
413 056fe1ba 2003-11-23 devnull * Lock b before unlocking c, so that others wait while we read.
415 056fe1ba 2003-11-23 devnull * You might think there is a race between this qlock(b) before qunlock(c)
416 056fe1ba 2003-11-23 devnull * and the qlock(c) while holding a qlock(b) in vtblockwrite. However,
417 056fe1ba 2003-11-23 devnull * the block here can never be the block in a vtblockwrite, so we're safe.
418 056fe1ba 2003-11-23 devnull * We're certainly living on the edge.
420 056fe1ba 2003-11-23 devnull qlock(&b->lk);
421 056fe1ba 2003-11-23 devnull b->nlock = 1;
422 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
424 7252036f 2005-11-02 devnull vtcachenread++;
425 056fe1ba 2003-11-23 devnull n = vtread(c->z, score, type, b->data, c->blocksize);
426 056fe1ba 2003-11-23 devnull if(n < 0){
427 a1882dc1 2004-06-17 devnull werrstr("vtread %V: %r", score);
428 eacc220a 2004-06-17 devnull if(chattyventi)
429 eacc220a 2004-06-17 devnull fprint(2, "read %V: %r\n", score);
430 056fe1ba 2003-11-23 devnull b->iostate = BioVentiError;
431 056fe1ba 2003-11-23 devnull vtblockput(b);
432 056fe1ba 2003-11-23 devnull return nil;
434 056fe1ba 2003-11-23 devnull vtzeroextend(type, b->data, n, c->blocksize);
435 056fe1ba 2003-11-23 devnull b->iostate = BioVenti;
436 056fe1ba 2003-11-23 devnull b->nlock = 1;
437 056fe1ba 2003-11-23 devnull return b;
441 056fe1ba 2003-11-23 devnull * The thread that has locked b may refer to it by
442 056fe1ba 2003-11-23 devnull * multiple names. Nlock counts the number of
443 056fe1ba 2003-11-23 devnull * references the locking thread holds. It will call
444 056fe1ba 2003-11-23 devnull * vtblockput once per reference.
447 056fe1ba 2003-11-23 devnull vtblockduplock(VtBlock *b)
449 056fe1ba 2003-11-23 devnull assert(b->nlock > 0);
450 056fe1ba 2003-11-23 devnull b->nlock++;
454 056fe1ba 2003-11-23 devnull * we're done with the block.
455 056fe1ba 2003-11-23 devnull * unlock it. can't use it after calling this.
458 056fe1ba 2003-11-23 devnull vtblockput(VtBlock* b)
460 056fe1ba 2003-11-23 devnull VtCache *c;
462 056fe1ba 2003-11-23 devnull if(b == nil)
465 056fe1ba 2003-11-23 devnull if(0)fprint(2, "vtblockput: %d: %x %d %d\n", getpid(), b->addr, c->nheap, b->iostate);
467 056fe1ba 2003-11-23 devnull if(--b->nlock > 0)
471 056fe1ba 2003-11-23 devnull * b->nlock should probably stay at zero while
472 056fe1ba 2003-11-23 devnull * the vtBlock is unlocked, but diskThread and vtSleep
473 056fe1ba 2003-11-23 devnull * conspire to assume that they can just qlock(&b->lk); vtblockput(b),
474 056fe1ba 2003-11-23 devnull * so we have to keep b->nlock set to 1 even
475 056fe1ba 2003-11-23 devnull * when the vtBlock is unlocked.
477 056fe1ba 2003-11-23 devnull assert(b->nlock == 0);
478 056fe1ba 2003-11-23 devnull b->nlock = 1;
480 056fe1ba 2003-11-23 devnull qunlock(&b->lk);
481 056fe1ba 2003-11-23 devnull c = b->c;
482 056fe1ba 2003-11-23 devnull qlock(&c->lk);
484 056fe1ba 2003-11-23 devnull if(--b->ref > 0){
485 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
489 056fe1ba 2003-11-23 devnull assert(b->ref == 0);
490 056fe1ba 2003-11-23 devnull switch(b->iostate){
491 056fe1ba 2003-11-23 devnull case BioVenti:
492 056fe1ba 2003-11-23 devnull //if(b->addr != NilBlock) print("blockput %d\n", b->addr);
493 056fe1ba 2003-11-23 devnull b->used = c->now++;
494 056fe1ba 2003-11-23 devnull case BioVentiError:
495 056fe1ba 2003-11-23 devnull heapins(b);
497 056fe1ba 2003-11-23 devnull case BioLocal:
500 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
504 056fe1ba 2003-11-23 devnull vtblockwrite(VtBlock *b)
506 056fe1ba 2003-11-23 devnull uchar score[VtScoreSize];
507 056fe1ba 2003-11-23 devnull VtCache *c;
511 056fe1ba 2003-11-23 devnull if(b->iostate != BioLocal){
512 0c148046 2004-06-16 devnull werrstr("vtblockwrite: not a local block");
513 0c148046 2004-06-16 devnull return -1;
516 056fe1ba 2003-11-23 devnull c = b->c;
517 056fe1ba 2003-11-23 devnull n = vtzerotruncate(b->type, b->data, c->blocksize);
518 7252036f 2005-11-02 devnull vtcachenwrite++;
519 a1882dc1 2004-06-17 devnull if(c->write(c->z, score, b->type, b->data, n) < 0)
520 056fe1ba 2003-11-23 devnull return -1;
522 056fe1ba 2003-11-23 devnull memmove(b->score, score, VtScoreSize);
524 056fe1ba 2003-11-23 devnull qlock(&c->lk);
525 056fe1ba 2003-11-23 devnull b->iostate = BioVenti;
526 056fe1ba 2003-11-23 devnull h = (u32int)(score[0]|(score[1]<<8)|(score[2]<<16)|(score[3]<<24)) % c->nhash;
527 056fe1ba 2003-11-23 devnull b->next = c->hash[h];
528 056fe1ba 2003-11-23 devnull c->hash[h] = b;
529 056fe1ba 2003-11-23 devnull if(b->next != nil)
530 056fe1ba 2003-11-23 devnull b->next->prev = &b->next;
531 056fe1ba 2003-11-23 devnull b->prev = &c->hash[h];
532 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
533 056fe1ba 2003-11-23 devnull return 0;
537 056fe1ba 2003-11-23 devnull vtcacheblocksize(VtCache *c)
539 056fe1ba 2003-11-23 devnull return c->blocksize;
542 056fe1ba 2003-11-23 devnull VtBlock*
543 056fe1ba 2003-11-23 devnull vtblockcopy(VtBlock *b)
545 056fe1ba 2003-11-23 devnull VtBlock *bb;
547 7252036f 2005-11-02 devnull vtcachencopy++;
548 056fe1ba 2003-11-23 devnull bb = vtcacheallocblock(b->c, b->type);
549 056fe1ba 2003-11-23 devnull if(bb == nil){
550 056fe1ba 2003-11-23 devnull vtblockput(b);
551 056fe1ba 2003-11-23 devnull return nil;
553 056fe1ba 2003-11-23 devnull memmove(bb->data, b->data, b->c->blocksize);
554 056fe1ba 2003-11-23 devnull vtblockput(b);
555 056fe1ba 2003-11-23 devnull return bb;
559 056fe1ba 2003-11-23 devnull vtlocaltoglobal(u32int addr, uchar score[VtScoreSize])
561 056fe1ba 2003-11-23 devnull memset(score, 0, 16);
562 056fe1ba 2003-11-23 devnull score[16] = addr>>24;
563 056fe1ba 2003-11-23 devnull score[17] = addr>>16;
564 056fe1ba 2003-11-23 devnull score[18] = addr>>8;
565 056fe1ba 2003-11-23 devnull score[19] = addr;
570 056fe1ba 2003-11-23 devnull vtglobaltolocal(uchar score[VtScoreSize])
572 056fe1ba 2003-11-23 devnull static uchar zero[16];
573 056fe1ba 2003-11-23 devnull if(memcmp(score, zero, 16) != 0)
574 056fe1ba 2003-11-23 devnull return NilBlock;
575 056fe1ba 2003-11-23 devnull return (score[16]<<24)|(score[17]<<16)|(score[18]<<8)|score[19];
