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;
18 6cd6f689 2006-05-05 devnull int vttracelevel;
21 056fe1ba 2003-11-23 devnull BioLocal = 1,
22 056fe1ba 2003-11-23 devnull BioVenti,
23 056fe1ba 2003-11-23 devnull BioReading,
24 056fe1ba 2003-11-23 devnull BioWriting,
25 056fe1ba 2003-11-23 devnull BioEmpty,
26 cbeb0b26 2006-04-01 devnull BioVentiError
29 cbeb0b26 2006-04-01 devnull BadHeap = ~0
31 056fe1ba 2003-11-23 devnull struct VtCache
33 056fe1ba 2003-11-23 devnull QLock lk;
34 056fe1ba 2003-11-23 devnull VtConn *z;
35 056fe1ba 2003-11-23 devnull u32int blocksize;
36 056fe1ba 2003-11-23 devnull u32int now; /* ticks for usage time stamps */
37 056fe1ba 2003-11-23 devnull VtBlock **hash; /* hash table for finding addresses */
38 056fe1ba 2003-11-23 devnull int nhash;
39 056fe1ba 2003-11-23 devnull VtBlock **heap; /* heap for finding victims */
40 056fe1ba 2003-11-23 devnull int nheap;
41 056fe1ba 2003-11-23 devnull VtBlock *block; /* all allocated blocks */
42 056fe1ba 2003-11-23 devnull int nblock;
43 056fe1ba 2003-11-23 devnull uchar *mem; /* memory for all blocks and data */
44 a1882dc1 2004-06-17 devnull int (*write)(VtConn*, uchar[VtScoreSize], uint, uchar*, int);
47 056fe1ba 2003-11-23 devnull static void cachecheck(VtCache*);
50 e87f5d7c 2005-07-13 devnull vtcachealloc(VtConn *z, int blocksize, ulong nblock)
52 056fe1ba 2003-11-23 devnull uchar *p;
53 056fe1ba 2003-11-23 devnull VtCache *c;
55 056fe1ba 2003-11-23 devnull VtBlock *b;
57 056fe1ba 2003-11-23 devnull c = vtmallocz(sizeof(VtCache));
59 056fe1ba 2003-11-23 devnull c->z = z;
60 056fe1ba 2003-11-23 devnull c->blocksize = (blocksize + 127) & ~127;
61 056fe1ba 2003-11-23 devnull c->nblock = nblock;
62 056fe1ba 2003-11-23 devnull c->nhash = nblock;
63 056fe1ba 2003-11-23 devnull c->hash = vtmallocz(nblock*sizeof(VtBlock*));
64 056fe1ba 2003-11-23 devnull c->heap = vtmallocz(nblock*sizeof(VtBlock*));
65 056fe1ba 2003-11-23 devnull c->block = vtmallocz(nblock*sizeof(VtBlock));
66 056fe1ba 2003-11-23 devnull c->mem = vtmallocz(nblock*c->blocksize);
67 a1882dc1 2004-06-17 devnull c->write = vtwrite;
69 056fe1ba 2003-11-23 devnull p = c->mem;
70 056fe1ba 2003-11-23 devnull for(i=0; i<nblock; i++){
71 056fe1ba 2003-11-23 devnull b = &c->block[i];
72 056fe1ba 2003-11-23 devnull b->addr = NilBlock;
73 056fe1ba 2003-11-23 devnull b->c = c;
74 056fe1ba 2003-11-23 devnull b->data = p;
75 056fe1ba 2003-11-23 devnull b->heap = i;
76 056fe1ba 2003-11-23 devnull c->heap[i] = b;
77 056fe1ba 2003-11-23 devnull p += c->blocksize;
79 056fe1ba 2003-11-23 devnull c->nheap = nblock;
80 056fe1ba 2003-11-23 devnull cachecheck(c);
81 056fe1ba 2003-11-23 devnull return c;
85 a1882dc1 2004-06-17 devnull * BUG This is here so that vbackup can override it and do some
86 a1882dc1 2004-06-17 devnull * pipelining of writes. Arguably vtwrite or vtwritepacket or the
87 a1882dc1 2004-06-17 devnull * cache itself should be providing this functionality.
90 a1882dc1 2004-06-17 devnull vtcachesetwrite(VtCache *c, int (*write)(VtConn*, uchar[VtScoreSize], uint, uchar*, int))
92 a1882dc1 2004-06-17 devnull if(write == nil)
93 a1882dc1 2004-06-17 devnull write = vtwrite;
94 a1882dc1 2004-06-17 devnull c->write = write;
98 056fe1ba 2003-11-23 devnull vtcachefree(VtCache *c)
102 056fe1ba 2003-11-23 devnull qlock(&c->lk);
104 056fe1ba 2003-11-23 devnull cachecheck(c);
105 056fe1ba 2003-11-23 devnull for(i=0; i<c->nblock; i++)
106 056fe1ba 2003-11-23 devnull assert(c->block[i].ref == 0);
108 056fe1ba 2003-11-23 devnull vtfree(c->hash);
109 056fe1ba 2003-11-23 devnull vtfree(c->heap);
110 056fe1ba 2003-11-23 devnull vtfree(c->block);
111 056fe1ba 2003-11-23 devnull vtfree(c->mem);
112 056fe1ba 2003-11-23 devnull vtfree(c);
115 056fe1ba 2003-11-23 devnull static void
116 056fe1ba 2003-11-23 devnull vtcachedump(VtCache *c)
119 056fe1ba 2003-11-23 devnull VtBlock *b;
121 056fe1ba 2003-11-23 devnull for(i=0; i<c->nblock; i++){
122 056fe1ba 2003-11-23 devnull b = &c->block[i];
123 056fe1ba 2003-11-23 devnull print("cache block %d: type %d score %V iostate %d addr %d ref %d nlock %d\n",
124 056fe1ba 2003-11-23 devnull i, b->type, b->score, b->iostate, b->addr, b->ref, b->nlock);
128 056fe1ba 2003-11-23 devnull static void
129 056fe1ba 2003-11-23 devnull cachecheck(VtCache *c)
131 056fe1ba 2003-11-23 devnull u32int size, now;
132 056fe1ba 2003-11-23 devnull int i, k, refed;
133 056fe1ba 2003-11-23 devnull VtBlock *b;
135 056fe1ba 2003-11-23 devnull size = c->blocksize;
136 056fe1ba 2003-11-23 devnull now = c->now;
138 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nheap; i++){
139 056fe1ba 2003-11-23 devnull if(c->heap[i]->heap != i)
140 056fe1ba 2003-11-23 devnull sysfatal("mis-heaped at %d: %d", i, c->heap[i]->heap);
141 056fe1ba 2003-11-23 devnull if(i > 0 && c->heap[(i - 1) >> 1]->used - now > c->heap[i]->used - now)
142 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
143 056fe1ba 2003-11-23 devnull k = (i << 1) + 1;
144 056fe1ba 2003-11-23 devnull if(k < c->nheap && c->heap[i]->used - now > c->heap[k]->used - now)
145 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
147 056fe1ba 2003-11-23 devnull if(k < c->nheap && c->heap[i]->used - now > c->heap[k]->used - now)
148 056fe1ba 2003-11-23 devnull sysfatal("bad heap ordering");
151 056fe1ba 2003-11-23 devnull refed = 0;
152 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nblock; i++){
153 056fe1ba 2003-11-23 devnull b = &c->block[i];
154 056fe1ba 2003-11-23 devnull if(b->data != &c->mem[i * size])
155 056fe1ba 2003-11-23 devnull sysfatal("mis-blocked at %d", i);
156 056fe1ba 2003-11-23 devnull if(b->ref && b->heap == BadHeap)
157 056fe1ba 2003-11-23 devnull refed++;
158 056fe1ba 2003-11-23 devnull else if(b->addr != NilBlock)
159 056fe1ba 2003-11-23 devnull refed++;
161 056fe1ba 2003-11-23 devnull if(c->nheap + refed != c->nblock){
162 056fe1ba 2003-11-23 devnull fprint(2, "cachecheck: nheap %d refed %d nblocks %d\n", c->nheap, refed, c->nblock);
163 cbeb0b26 2006-04-01 devnull /*vtcachedump(c); */
165 056fe1ba 2003-11-23 devnull assert(c->nheap + refed == c->nblock);
166 056fe1ba 2003-11-23 devnull refed = 0;
167 056fe1ba 2003-11-23 devnull for(i = 0; i < c->nblock; i++){
168 056fe1ba 2003-11-23 devnull b = &c->block[i];
169 056fe1ba 2003-11-23 devnull if(b->ref){
170 056fe1ba 2003-11-23 devnull if(1)fprint(2, "a=%ud %V ref=%d\n", b->addr, b->score, b->ref);
171 056fe1ba 2003-11-23 devnull refed++;
174 056fe1ba 2003-11-23 devnull if(refed > 0)fprint(2, "cachecheck: in used %d\n", refed);
177 056fe1ba 2003-11-23 devnull static int
178 056fe1ba 2003-11-23 devnull upheap(int i, VtBlock *b)
180 056fe1ba 2003-11-23 devnull VtBlock *bb;
181 056fe1ba 2003-11-23 devnull u32int now;
183 056fe1ba 2003-11-23 devnull VtCache *c;
185 056fe1ba 2003-11-23 devnull c = b->c;
186 056fe1ba 2003-11-23 devnull now = c->now;
187 056fe1ba 2003-11-23 devnull for(; i != 0; i = p){
188 056fe1ba 2003-11-23 devnull p = (i - 1) >> 1;
189 056fe1ba 2003-11-23 devnull bb = c->heap[p];
190 056fe1ba 2003-11-23 devnull if(b->used - now >= bb->used - now)
192 056fe1ba 2003-11-23 devnull c->heap[i] = bb;
193 056fe1ba 2003-11-23 devnull bb->heap = i;
195 056fe1ba 2003-11-23 devnull c->heap[i] = b;
196 056fe1ba 2003-11-23 devnull b->heap = i;
198 056fe1ba 2003-11-23 devnull return i;
201 056fe1ba 2003-11-23 devnull static int
202 056fe1ba 2003-11-23 devnull downheap(int i, VtBlock *b)
204 056fe1ba 2003-11-23 devnull VtBlock *bb;
205 056fe1ba 2003-11-23 devnull u32int now;
207 056fe1ba 2003-11-23 devnull VtCache *c;
209 056fe1ba 2003-11-23 devnull c = b->c;
210 056fe1ba 2003-11-23 devnull now = c->now;
211 056fe1ba 2003-11-23 devnull for(; ; i = k){
212 056fe1ba 2003-11-23 devnull k = (i << 1) + 1;
213 056fe1ba 2003-11-23 devnull if(k >= c->nheap)
215 056fe1ba 2003-11-23 devnull if(k + 1 < c->nheap && c->heap[k]->used - now > c->heap[k + 1]->used - now)
217 056fe1ba 2003-11-23 devnull bb = c->heap[k];
218 056fe1ba 2003-11-23 devnull if(b->used - now <= bb->used - now)
220 056fe1ba 2003-11-23 devnull c->heap[i] = bb;
221 056fe1ba 2003-11-23 devnull bb->heap = i;
223 056fe1ba 2003-11-23 devnull c->heap[i] = b;
224 056fe1ba 2003-11-23 devnull b->heap = i;
225 056fe1ba 2003-11-23 devnull return i;
229 056fe1ba 2003-11-23 devnull * Delete a block from the heap.
230 056fe1ba 2003-11-23 devnull * Called with c->lk held.
232 056fe1ba 2003-11-23 devnull static void
233 056fe1ba 2003-11-23 devnull heapdel(VtBlock *b)
235 056fe1ba 2003-11-23 devnull int i, si;
236 056fe1ba 2003-11-23 devnull VtCache *c;
238 056fe1ba 2003-11-23 devnull c = b->c;
240 056fe1ba 2003-11-23 devnull si = b->heap;
241 056fe1ba 2003-11-23 devnull if(si == BadHeap)
243 056fe1ba 2003-11-23 devnull b->heap = BadHeap;
244 056fe1ba 2003-11-23 devnull c->nheap--;
245 056fe1ba 2003-11-23 devnull if(si == c->nheap)
247 056fe1ba 2003-11-23 devnull b = c->heap[c->nheap];
248 056fe1ba 2003-11-23 devnull i = upheap(si, b);
249 056fe1ba 2003-11-23 devnull if(i == si)
250 056fe1ba 2003-11-23 devnull downheap(i, b);
254 056fe1ba 2003-11-23 devnull * Insert a block into the heap.
255 056fe1ba 2003-11-23 devnull * Called with c->lk held.
257 056fe1ba 2003-11-23 devnull static void
258 056fe1ba 2003-11-23 devnull heapins(VtBlock *b)
260 056fe1ba 2003-11-23 devnull assert(b->heap == BadHeap);
261 056fe1ba 2003-11-23 devnull upheap(b->c->nheap++, b);
265 056fe1ba 2003-11-23 devnull * locate the vtBlock with the oldest second to last use.
266 056fe1ba 2003-11-23 devnull * remove it from the heap, and fix up the heap.
268 056fe1ba 2003-11-23 devnull /* called with c->lk held */
269 056fe1ba 2003-11-23 devnull static VtBlock*
270 056fe1ba 2003-11-23 devnull vtcachebumpblock(VtCache *c)
272 056fe1ba 2003-11-23 devnull VtBlock *b;
275 056fe1ba 2003-11-23 devnull * locate the vtBlock with the oldest second to last use.
276 056fe1ba 2003-11-23 devnull * remove it from the heap, and fix up the heap.
278 056fe1ba 2003-11-23 devnull if(c->nheap == 0){
279 056fe1ba 2003-11-23 devnull vtcachedump(c);
280 7cb74894 2004-06-17 devnull fprint(2, "vtcachebumpblock: no free blocks in vtCache");
281 7cb74894 2004-06-17 devnull abort();
283 056fe1ba 2003-11-23 devnull b = c->heap[0];
284 056fe1ba 2003-11-23 devnull heapdel(b);
286 056fe1ba 2003-11-23 devnull assert(b->heap == BadHeap);
287 056fe1ba 2003-11-23 devnull assert(b->ref == 0);
290 056fe1ba 2003-11-23 devnull * unchain the vtBlock from hash chain if any
292 056fe1ba 2003-11-23 devnull if(b->prev){
293 056fe1ba 2003-11-23 devnull *(b->prev) = b->next;
294 056fe1ba 2003-11-23 devnull if(b->next)
295 056fe1ba 2003-11-23 devnull b->next->prev = b->prev;
296 056fe1ba 2003-11-23 devnull b->prev = nil;
300 056fe1ba 2003-11-23 devnull if(0)fprint(2, "droping %x:%V\n", b->addr, b->score);
301 056fe1ba 2003-11-23 devnull /* set vtBlock to a reasonable state */
302 056fe1ba 2003-11-23 devnull b->ref = 1;
303 056fe1ba 2003-11-23 devnull b->iostate = BioEmpty;
304 056fe1ba 2003-11-23 devnull return b;
308 056fe1ba 2003-11-23 devnull * fetch a local block from the memory cache.
309 056fe1ba 2003-11-23 devnull * if it's not there, load it, bumping some other Block.
310 056fe1ba 2003-11-23 devnull * if we're out of free blocks, we're screwed.
312 056fe1ba 2003-11-23 devnull VtBlock*
313 056fe1ba 2003-11-23 devnull vtcachelocal(VtCache *c, u32int addr, int type)
315 056fe1ba 2003-11-23 devnull VtBlock *b;
317 23fb2edb 2005-07-24 devnull if(addr == 0)
318 23fb2edb 2005-07-24 devnull sysfatal("vtcachelocal: asked for nonexistent block 0");
319 23fb2edb 2005-07-24 devnull if(addr > c->nblock)
320 23fb2edb 2005-07-24 devnull sysfatal("vtcachelocal: asked for block #%ud; only %d blocks",
321 056fe1ba 2003-11-23 devnull addr, c->nblock);
323 23fb2edb 2005-07-24 devnull b = &c->block[addr-1];
324 056fe1ba 2003-11-23 devnull if(b->addr == NilBlock || b->iostate != BioLocal)
325 056fe1ba 2003-11-23 devnull sysfatal("vtcachelocal: block is not local");
327 056fe1ba 2003-11-23 devnull if(b->type != type)
328 056fe1ba 2003-11-23 devnull sysfatal("vtcachelocal: block has wrong type %d != %d", b->type, type);
330 056fe1ba 2003-11-23 devnull qlock(&c->lk);
331 056fe1ba 2003-11-23 devnull b->ref++;
332 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
334 056fe1ba 2003-11-23 devnull qlock(&b->lk);
335 056fe1ba 2003-11-23 devnull b->nlock = 1;
336 056fe1ba 2003-11-23 devnull return b;
339 056fe1ba 2003-11-23 devnull VtBlock*
340 056fe1ba 2003-11-23 devnull vtcacheallocblock(VtCache *c, int type)
342 056fe1ba 2003-11-23 devnull VtBlock *b;
344 056fe1ba 2003-11-23 devnull qlock(&c->lk);
345 056fe1ba 2003-11-23 devnull b = vtcachebumpblock(c);
346 056fe1ba 2003-11-23 devnull b->iostate = BioLocal;
347 056fe1ba 2003-11-23 devnull b->type = type;
348 23fb2edb 2005-07-24 devnull b->addr = (b - c->block)+1;
349 056fe1ba 2003-11-23 devnull vtzeroextend(type, b->data, 0, c->blocksize);
350 056fe1ba 2003-11-23 devnull vtlocaltoglobal(b->addr, b->score);
351 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
353 056fe1ba 2003-11-23 devnull qlock(&b->lk);
354 056fe1ba 2003-11-23 devnull b->nlock = 1;
356 056fe1ba 2003-11-23 devnull return b;
360 056fe1ba 2003-11-23 devnull * fetch a global (Venti) block from the memory cache.
361 056fe1ba 2003-11-23 devnull * if it's not there, load it, bumping some other block.
363 056fe1ba 2003-11-23 devnull VtBlock*
364 056fe1ba 2003-11-23 devnull vtcacheglobal(VtCache *c, uchar score[VtScoreSize], int type)
366 056fe1ba 2003-11-23 devnull VtBlock *b;
367 056fe1ba 2003-11-23 devnull ulong h;
369 056fe1ba 2003-11-23 devnull u32int addr;
371 6cd6f689 2006-05-05 devnull if(vttracelevel)
372 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d from %p\n", score, type, getcallerpc(&c));
373 056fe1ba 2003-11-23 devnull addr = vtglobaltolocal(score);
374 6cd6f689 2006-05-05 devnull if(addr != NilBlock){
375 6cd6f689 2006-05-05 devnull if(vttracelevel)
376 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => local\n", score, type);
377 056fe1ba 2003-11-23 devnull return vtcachelocal(c, addr, type);
380 056fe1ba 2003-11-23 devnull h = (u32int)(score[0]|(score[1]<<8)|(score[2]<<16)|(score[3]<<24)) % c->nhash;
383 056fe1ba 2003-11-23 devnull * look for the block in the cache
385 056fe1ba 2003-11-23 devnull qlock(&c->lk);
386 056fe1ba 2003-11-23 devnull for(b = c->hash[h]; b != nil; b = b->next){
387 056fe1ba 2003-11-23 devnull if(b->addr != NilBlock || memcmp(b->score, score, VtScoreSize) != 0 || b->type != type)
388 056fe1ba 2003-11-23 devnull continue;
389 056fe1ba 2003-11-23 devnull heapdel(b);
390 056fe1ba 2003-11-23 devnull b->ref++;
391 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
392 6cd6f689 2006-05-05 devnull if(vttracelevel)
393 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => found in cache %p; locking\n", score, type, b);
394 056fe1ba 2003-11-23 devnull qlock(&b->lk);
395 056fe1ba 2003-11-23 devnull b->nlock = 1;
396 0c148046 2004-06-16 devnull if(b->iostate == BioVentiError){
397 eacc220a 2004-06-17 devnull if(chattyventi)
398 eacc220a 2004-06-17 devnull fprint(2, "cached read error for %V\n", score);
399 6cd6f689 2006-05-05 devnull if(vttracelevel)
400 6df24754 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => cache read error\n", score, type);
401 0c148046 2004-06-16 devnull vtblockput(b);
402 6df24754 2006-05-05 devnull werrstr("venti i/o error");
403 0c148046 2004-06-16 devnull return nil;
405 6cd6f689 2006-05-05 devnull if(vttracelevel)
406 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => found in cache; returning\n", score, type);
407 056fe1ba 2003-11-23 devnull return b;
411 056fe1ba 2003-11-23 devnull * not found
413 056fe1ba 2003-11-23 devnull b = vtcachebumpblock(c);
414 056fe1ba 2003-11-23 devnull b->addr = NilBlock;
415 056fe1ba 2003-11-23 devnull b->type = type;
416 056fe1ba 2003-11-23 devnull memmove(b->score, score, VtScoreSize);
417 056fe1ba 2003-11-23 devnull /* chain onto correct hash */
418 056fe1ba 2003-11-23 devnull b->next = c->hash[h];
419 056fe1ba 2003-11-23 devnull c->hash[h] = b;
420 056fe1ba 2003-11-23 devnull if(b->next != nil)
421 056fe1ba 2003-11-23 devnull b->next->prev = &b->next;
422 056fe1ba 2003-11-23 devnull b->prev = &c->hash[h];
425 056fe1ba 2003-11-23 devnull * Lock b before unlocking c, so that others wait while we read.
427 056fe1ba 2003-11-23 devnull * You might think there is a race between this qlock(b) before qunlock(c)
428 056fe1ba 2003-11-23 devnull * and the qlock(c) while holding a qlock(b) in vtblockwrite. However,
429 056fe1ba 2003-11-23 devnull * the block here can never be the block in a vtblockwrite, so we're safe.
430 056fe1ba 2003-11-23 devnull * We're certainly living on the edge.
432 6cd6f689 2006-05-05 devnull if(vttracelevel)
433 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => bumped; locking %p\n", score, type, b);
434 056fe1ba 2003-11-23 devnull qlock(&b->lk);
435 056fe1ba 2003-11-23 devnull b->nlock = 1;
436 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
438 7252036f 2005-11-02 devnull vtcachenread++;
439 056fe1ba 2003-11-23 devnull n = vtread(c->z, score, type, b->data, c->blocksize);
440 056fe1ba 2003-11-23 devnull if(n < 0){
441 eacc220a 2004-06-17 devnull if(chattyventi)
442 eacc220a 2004-06-17 devnull fprint(2, "read %V: %r\n", score);
443 6cd6f689 2006-05-05 devnull if(vttracelevel)
444 6cd6f689 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => bumped; read error\n", score, type);
445 056fe1ba 2003-11-23 devnull b->iostate = BioVentiError;
446 056fe1ba 2003-11-23 devnull vtblockput(b);
447 056fe1ba 2003-11-23 devnull return nil;
449 056fe1ba 2003-11-23 devnull vtzeroextend(type, b->data, n, c->blocksize);
450 056fe1ba 2003-11-23 devnull b->iostate = BioVenti;
451 056fe1ba 2003-11-23 devnull b->nlock = 1;
452 6cd6f689 2006-05-05 devnull if(vttracelevel)
453 6df24754 2006-05-05 devnull fprint(2, "vtcacheglobal %V %d => loaded into cache; returning\n", score, type);
454 6df24754 2006-05-05 devnull return b;
458 056fe1ba 2003-11-23 devnull * The thread that has locked b may refer to it by
459 056fe1ba 2003-11-23 devnull * multiple names. Nlock counts the number of
460 056fe1ba 2003-11-23 devnull * references the locking thread holds. It will call
461 056fe1ba 2003-11-23 devnull * vtblockput once per reference.
464 056fe1ba 2003-11-23 devnull vtblockduplock(VtBlock *b)
466 056fe1ba 2003-11-23 devnull assert(b->nlock > 0);
467 056fe1ba 2003-11-23 devnull b->nlock++;
471 056fe1ba 2003-11-23 devnull * we're done with the block.
472 056fe1ba 2003-11-23 devnull * unlock it. can't use it after calling this.
475 056fe1ba 2003-11-23 devnull vtblockput(VtBlock* b)
477 056fe1ba 2003-11-23 devnull VtCache *c;
479 056fe1ba 2003-11-23 devnull if(b == nil)
482 056fe1ba 2003-11-23 devnull if(0)fprint(2, "vtblockput: %d: %x %d %d\n", getpid(), b->addr, c->nheap, b->iostate);
483 6cd6f689 2006-05-05 devnull if(vttracelevel)
484 6cd6f689 2006-05-05 devnull fprint(2, "vtblockput %p from %p\n", b, getcallerpc(&b));
486 056fe1ba 2003-11-23 devnull if(--b->nlock > 0)
490 056fe1ba 2003-11-23 devnull * b->nlock should probably stay at zero while
491 056fe1ba 2003-11-23 devnull * the vtBlock is unlocked, but diskThread and vtSleep
492 056fe1ba 2003-11-23 devnull * conspire to assume that they can just qlock(&b->lk); vtblockput(b),
493 056fe1ba 2003-11-23 devnull * so we have to keep b->nlock set to 1 even
494 056fe1ba 2003-11-23 devnull * when the vtBlock is unlocked.
496 056fe1ba 2003-11-23 devnull assert(b->nlock == 0);
497 056fe1ba 2003-11-23 devnull b->nlock = 1;
499 056fe1ba 2003-11-23 devnull qunlock(&b->lk);
500 056fe1ba 2003-11-23 devnull c = b->c;
501 056fe1ba 2003-11-23 devnull qlock(&c->lk);
503 056fe1ba 2003-11-23 devnull if(--b->ref > 0){
504 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
508 056fe1ba 2003-11-23 devnull assert(b->ref == 0);
509 056fe1ba 2003-11-23 devnull switch(b->iostate){
510 056fe1ba 2003-11-23 devnull case BioVenti:
511 cbeb0b26 2006-04-01 devnull /*if(b->addr != NilBlock) print("blockput %d\n", b->addr); */
512 056fe1ba 2003-11-23 devnull b->used = c->now++;
513 056fe1ba 2003-11-23 devnull case BioVentiError:
514 056fe1ba 2003-11-23 devnull heapins(b);
516 056fe1ba 2003-11-23 devnull case BioLocal:
519 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
523 056fe1ba 2003-11-23 devnull vtblockwrite(VtBlock *b)
525 056fe1ba 2003-11-23 devnull uchar score[VtScoreSize];
526 056fe1ba 2003-11-23 devnull VtCache *c;
530 056fe1ba 2003-11-23 devnull if(b->iostate != BioLocal){
531 0c148046 2004-06-16 devnull werrstr("vtblockwrite: not a local block");
532 0c148046 2004-06-16 devnull return -1;
535 056fe1ba 2003-11-23 devnull c = b->c;
536 056fe1ba 2003-11-23 devnull n = vtzerotruncate(b->type, b->data, c->blocksize);
537 7252036f 2005-11-02 devnull vtcachenwrite++;
538 a1882dc1 2004-06-17 devnull if(c->write(c->z, score, b->type, b->data, n) < 0)
539 056fe1ba 2003-11-23 devnull return -1;
541 056fe1ba 2003-11-23 devnull memmove(b->score, score, VtScoreSize);
543 056fe1ba 2003-11-23 devnull qlock(&c->lk);
544 056fe1ba 2003-11-23 devnull b->iostate = BioVenti;
545 056fe1ba 2003-11-23 devnull h = (u32int)(score[0]|(score[1]<<8)|(score[2]<<16)|(score[3]<<24)) % c->nhash;
546 056fe1ba 2003-11-23 devnull b->next = c->hash[h];
547 056fe1ba 2003-11-23 devnull c->hash[h] = b;
548 056fe1ba 2003-11-23 devnull if(b->next != nil)
549 056fe1ba 2003-11-23 devnull b->next->prev = &b->next;
550 056fe1ba 2003-11-23 devnull b->prev = &c->hash[h];
551 056fe1ba 2003-11-23 devnull qunlock(&c->lk);
552 056fe1ba 2003-11-23 devnull return 0;
556 056fe1ba 2003-11-23 devnull vtcacheblocksize(VtCache *c)
558 056fe1ba 2003-11-23 devnull return c->blocksize;
561 056fe1ba 2003-11-23 devnull VtBlock*
562 056fe1ba 2003-11-23 devnull vtblockcopy(VtBlock *b)
564 056fe1ba 2003-11-23 devnull VtBlock *bb;
566 7252036f 2005-11-02 devnull vtcachencopy++;
567 056fe1ba 2003-11-23 devnull bb = vtcacheallocblock(b->c, b->type);
568 056fe1ba 2003-11-23 devnull if(bb == nil){
569 056fe1ba 2003-11-23 devnull vtblockput(b);
570 056fe1ba 2003-11-23 devnull return nil;
572 056fe1ba 2003-11-23 devnull memmove(bb->data, b->data, b->c->blocksize);
573 056fe1ba 2003-11-23 devnull vtblockput(b);
574 056fe1ba 2003-11-23 devnull return bb;
578 056fe1ba 2003-11-23 devnull vtlocaltoglobal(u32int addr, uchar score[VtScoreSize])
580 056fe1ba 2003-11-23 devnull memset(score, 0, 16);
581 056fe1ba 2003-11-23 devnull score[16] = addr>>24;
582 056fe1ba 2003-11-23 devnull score[17] = addr>>16;
583 056fe1ba 2003-11-23 devnull score[18] = addr>>8;
584 056fe1ba 2003-11-23 devnull score[19] = addr;
589 056fe1ba 2003-11-23 devnull vtglobaltolocal(uchar score[VtScoreSize])
591 056fe1ba 2003-11-23 devnull static uchar zero[16];
592 056fe1ba 2003-11-23 devnull if(memcmp(score, zero, 16) != 0)
593 056fe1ba 2003-11-23 devnull return NilBlock;
594 056fe1ba 2003-11-23 devnull return (score[16]<<24)|(score[17]<<16)|(score[18]<<8)|score[19];
