1 /*
2  * Archiver.  In charge of sending blocks to Venti.
3  */
4 
5 #include "stdinc.h"
6 #include "dat.h"
7 #include "fns.h"
8 #include "error.h"
9 
10 #include "9.h"	/* for consPrint */
11 
12 #define DEBUG 0
13 
14 static void archThread(void*);
15 
16 struct Arch
17 {
18 	int ref;
19 	uint blockSize;
20 	uint diskSize;
21 	Cache *c;
22 	Fs *fs;
23 	VtConn *z;
24 
25 	QLock lk;
26 	Rendez starve;
27 	Rendez die;
28 };
29 
30 Arch *
31 archInit(Cache *c, Disk *disk, Fs *fs, VtConn *z)
32 {
33 	Arch *a;
34 
35 	a = vtmallocz(sizeof(Arch));
36 
37 	a->c = c;
38 	a->z = z;
39 	a->fs = fs;
40 	a->blockSize = diskBlockSize(disk);
41 	a->starve.l = &a->lk;
42 
43 	a->ref = 2;
44 	proccreate(archThread, a, STACK);
45 
46 	return a;
47 }
48 
49 void
50 archFree(Arch *a)
51 {
52 	/* kill slave */
53 	qlock(&a->lk);
54 	a->die.l = &a->lk;
55 	rwakeup(&a->starve);
56 	while(a->ref > 1)
57 		rsleep(&a->die);
58 	qunlock(&a->lk);
59 	vtfree(a);
60 }
61 
62 static int
63 ventiSend(Arch *a, Block *b, uchar *data)
64 {
65 	uint n;
66 	uchar score[VtScoreSize];
67 
68 	if(DEBUG > 1)
69 		fprint(2, "ventiSend: sending %#ux %L to venti\n", b->addr, &b->l);
70 	n = vtzerotruncate(vtType[b->l.type], data, a->blockSize);
71 	if(DEBUG > 1)
72 		fprint(2, "ventiSend: truncate %d to %d\n", a->blockSize, n);
73 	if(vtwrite(a->z, score, vtType[b->l.type], data, n) < 0){
74 		fprint(2, "ventiSend: vtwrite block %#ux failed: %r\n", b->addr);
75 		return 0;
76 	}
77 	if(vtsha1check(score, data, n) < 0){
78 		uchar score2[VtScoreSize];
79 		vtsha1(score2, data, n);
80 		fprint(2, "ventiSend: vtwrite block %#ux failed vtsha1check %V %V\n",
81 			b->addr, score, score2);
82 		return 0;
83 	}
84 	if(vtsync(a->z) < 0)
85 		return 0;
86 	return 1;
87 }
88 
89 /*
90  * parameters for recursion; there are so many,
91  * and some only change occasionally.  this is
92  * easier than spelling things out at each call.
93  */
94 typedef struct Param Param;
95 struct Param
96 {
97 	/* these never change */
98 	uint snapEpoch;	/* epoch for snapshot being archived */
99 	uint blockSize;
100 	Cache *c;
101 	Arch *a;
102 
103 	/* changes on every call */
104 	uint depth;
105 
106 	/* statistics */
107 	uint nfixed;
108 	uint nsend;
109 	uint nvisit;
110 	uint nfailsend;
111 	uint maxdepth;
112 	uint nreclaim;
113 	uint nfake;
114 	uint nreal;
115 
116 	/* these occasionally change (must save old values and put back) */
117 	uint dsize;
118 	uint psize;
119 
120 	/* return value; avoids using stack space */
121 	Label l;
122 	uchar score[VtScoreSize];
123 };
124 
125 static void
126 shaBlock(uchar score[VtScoreSize], Block *b, uchar *data, uint bsize)
127 {
128 	vtsha1(score, data, vtzerotruncate(vtType[b->l.type], data, bsize));
129 }
130 
131 static uchar*
132 copyBlock(Block *b, u32int blockSize)
133 {
134 	uchar *data;
135 
136 	data = vtmalloc(blockSize);
137 	if(data == nil)
138 		return nil;
139 	memmove(data, b->data, blockSize);
140 	return data;
141 }
142 
143 /*
144  * Walk over the block tree, archiving it to Venti.
145  *
146  * We don't archive the snapshots. Instead we zero the
147  * entries in a temporary copy of the block and archive that.
148  *
149  * Return value is:
150  *
151  *	ArchFailure	some error occurred
152  *	ArchSuccess	block and all children archived
153  * 	ArchFaked	success, but block or children got copied
154  */
155 enum
156 {
157 	ArchFailure,
158 	ArchSuccess,
159 	ArchFaked,
160 };
161 static int
162 archWalk(Param *p, u32int addr, uchar type, u32int tag)
163 {
164 	int ret, i, x, psize, dsize;
165 	uchar *data, score[VtScoreSize];
166 	Block *b;
167 	Label l;
168 	Entry *e;
169 	WalkPtr w;
170 	char err[ERRMAX];
171 
172 	p->nvisit++;
173 
174 	b = cacheLocalData(p->c, addr, type, tag, OReadWrite,0);
175 	if(b == nil){
176 		fprint(2, "archive(%ud, %#ux): cannot find block: %r\n", p->snapEpoch, addr);
177 		rerrstr(err, sizeof err);
178 		if(strcmp(err, ELabelMismatch) == 0){
179 			/* might as well plod on so we write _something_ to Venti */
180 			memmove(p->score, vtzeroscore, VtScoreSize);
181 			return ArchFaked;
182 		}
183 		return ArchFailure;
184 	}
185 
186 	if(DEBUG) fprint(2, "%*sarchive(%ud, %#ux): block label %L\n",
187 		p->depth*2, "",  p->snapEpoch, b->addr, &b->l);
188 	p->depth++;
189 	if(p->depth > p->maxdepth)
190 		p->maxdepth = p->depth;
191 
192 	data = b->data;
193 	if((b->l.state&BsVenti) == 0){
194 		initWalk(&w, b, b->l.type==BtDir ? p->dsize : p->psize);
195 		for(i=0; nextWalk(&w, score, &type, &tag, &e); i++){
196 			if(e){
197 				if(!(e->flags&VtEntryActive))
198 					continue;
199 				if((e->snap && !e->archive)
200 				|| (e->flags&VtEntryNoArchive)){
201 					if(0) fprint(2, "snap; faking %#ux\n", b->addr);
202 					if(data == b->data){
203 						data = copyBlock(b, p->blockSize);
204 						if(data == nil){
205 							ret = ArchFailure;
206 							goto Out;
207 						}
208 						w.data = data;
209 					}
210 					memmove(e->score, vtzeroscore, VtScoreSize);
211 					e->depth = 0;
212 					e->size = 0;
213 					e->tag = 0;
214 					e->flags &= ~VtEntryLocal;
215 					entryPack(e, data, w.n-1);
216 					continue;
217 				}
218 			}
219 			addr = globalToLocal(score);
220 			if(addr == NilBlock)
221 				continue;
222 			dsize = p->dsize;
223 			psize = p->psize;
224 			if(e){
225 				p->dsize= e->dsize;
226 				p->psize = e->psize;
227 			}
228 			qunlock(&b->lk);
229 			x = archWalk(p, addr, type, tag);
230 			qlock(&b->lk);
231 			if(e){
232 				p->dsize = dsize;
233 				p->psize = psize;
234 			}
235 			while(b->iostate != BioClean && b->iostate != BioDirty)
236 				rsleep(&b->ioready);
237 			switch(x){
238 			case ArchFailure:
239 				fprint(2, "archWalk %#ux failed; ptr is in %#ux offset %d\n",
240 					addr, b->addr, i);
241 				ret = ArchFailure;
242 				goto Out;
243 			case ArchFaked:
244 				/*
245 				 * When we're writing the entry for an archive directory
246 				 * (like /archive/2003/1215) then even if we've faked
247 				 * any data, record the score unconditionally.
248 				 * This way, we will always record the Venti score here.
249 				 * Otherwise, temporary data or corrupted file system
250 				 * would cause us to keep holding onto the on-disk
251 				 * copy of the archive.
252 				 */
253 				if(e==nil || !e->archive)
254 				if(data == b->data){
255 if(0) fprint(2, "faked %#ux, faking %#ux (%V)\n", addr, b->addr, p->score);
256 					data = copyBlock(b, p->blockSize);
257 					if(data == nil){
258 						ret = ArchFailure;
259 						goto Out;
260 					}
261 					w.data = data;
262 				}
263 				/* fall through */
264 if(0) fprint(2, "falling\n");
265 			case ArchSuccess:
266 				if(e){
267 					memmove(e->score, p->score, VtScoreSize);
268 					e->flags &= ~VtEntryLocal;
269 					entryPack(e, data, w.n-1);
270 				}else
271 					memmove(data+(w.n-1)*VtScoreSize, p->score, VtScoreSize);
272 				if(data == b->data){
273 					blockDirty(b);
274 					/*
275 					 * If b is in the active tree, then we need to note that we've
276 					 * just removed addr from the active tree (replacing it with the 
277 					 * copy we just stored to Venti).  If addr is in other snapshots,
278 					 * this will close addr but not free it, since it has a non-empty
279 					 * epoch range.
280 					 *
281 					 * If b is in the active tree but has been copied (this can happen
282 					 * if we get killed at just the right moment), then we will
283 					 * mistakenly leak its kids.  
284 					 *
285 					 * The children of an archive directory (e.g., /archive/2004/0604)
286 					 * are not treated as in the active tree.
287 					 */
288 					if((b->l.state&BsCopied)==0 && (e==nil || e->snap==0))
289 						blockRemoveLink(b, addr, p->l.type, p->l.tag, 0);
290 				}
291 				break;
292 			}
293 		}
294 
295 		if(!ventiSend(p->a, b, data)){
296 			p->nfailsend++;
297 			ret = ArchFailure;
298 			goto Out;
299 		}
300 		p->nsend++;
301 		if(data != b->data)
302 			p->nfake++;
303 		if(data == b->data){	/* not faking it, so update state */
304 			p->nreal++;
305 			l = b->l;
306 			l.state |= BsVenti;
307 			if(!blockSetLabel(b, &l, 0)){
308 				ret = ArchFailure;
309 				goto Out;
310 			}
311 		}
312 	}
313 
314 	shaBlock(p->score, b, data, p->blockSize);
315 if(0) fprint(2, "ventisend %V %p %p %p\n", p->score, data, b->data, w.data);
316 	ret = data!=b->data ? ArchFaked : ArchSuccess;
317 	p->l = b->l;
318 Out:
319 	if(data != b->data)
320 		vtfree(data);
321 	p->depth--;
322 	blockPut(b);
323 	return ret;
324 }
325 
326 static void
327 archThread(void *v)
328 {
329 	Arch *a = v;
330 	Block *b;
331 	Param p;
332 	Super super;
333 	int ret;
334 	u32int addr;
335 	uchar rbuf[VtRootSize];
336 	VtRoot root;
337 
338 	threadsetname("arch");
339 
340 	for(;;){
341 		/* look for work */
342 		wlock(&a->fs->elk);
343 		b = superGet(a->c, &super);
344 		if(b == nil){
345 			wunlock(&a->fs->elk);
346 			fprint(2, "archThread: superGet: %r\n");
347 			sleep(60*1000);
348 			continue;
349 		}
350 		addr = super.next;
351 		if(addr != NilBlock && super.current == NilBlock){
352 			super.current = addr;
353 			super.next = NilBlock;
354 			superPack(&super, b->data);
355 			blockDirty(b);
356 		}else
357 			addr = super.current;
358 		blockPut(b);
359 		wunlock(&a->fs->elk);
360 
361 		if(addr == NilBlock){
362 			/* wait for work */
363 			qlock(&a->lk);
364 			rsleep(&a->starve);
365 			if(a->die.l != nil)
366 				goto Done;
367 			qunlock(&a->lk);
368 			continue;
369 		}
370 
371 sleep(10*1000);	/* window of opportunity to provoke races */
372 
373 		/* do work */
374 		memset(&p, 0, sizeof p);
375 		p.blockSize = a->blockSize;
376 		p.dsize = 3*VtEntrySize;	/* root has three Entries */
377 		p.c = a->c;
378 		p.a = a;
379 
380 		ret = archWalk(&p, addr, BtDir, RootTag);
381 		switch(ret){
382 		default:
383 			abort();
384 		case ArchFailure:
385 			fprint(2, "archiveBlock %#ux: %r\n", addr);
386 			sleep(60*1000);
387 			continue;
388 		case ArchSuccess:
389 		case ArchFaked:
390 			break;
391 		}
392 
393 		if(0) fprint(2, "archiveSnapshot 0x%#ux: maxdepth %ud nfixed %ud"
394 			" send %ud nfailsend %ud nvisit %ud"
395 			" nreclaim %ud nfake %ud nreal %ud\n",
396 			addr, p.maxdepth, p.nfixed,
397 			p.nsend, p.nfailsend, p.nvisit,
398 			p.nreclaim, p.nfake, p.nreal);
399 		if(0) fprint(2, "archiveBlock %V (%ud)\n", p.score, p.blockSize);
400 
401 		/* tie up vac root */
402 		memset(&root, 0, sizeof root);
403 		strecpy(root.type, root.type+sizeof root.type, "vac");
404 		strecpy(root.name, root.name+sizeof root.name, "fossil");
405 		memmove(root.score, p.score, VtScoreSize);
406 		memmove(root.prev, super.last, VtScoreSize);
407 		root.blocksize = a->blockSize;
408 		vtrootpack(&root, rbuf);
409 		if(vtwrite(a->z, p.score, VtRootType, rbuf, VtRootSize) < 0
410 		|| vtsha1check(p.score, rbuf, VtRootSize) < 0){
411 			fprint(2, "vtWriteBlock %#ux: %r\n", addr);
412 			sleep(60*1000);
413 			continue;
414 		}
415 
416 		/* record success */
417 		wlock(&a->fs->elk);
418 		b = superGet(a->c, &super);
419 		if(b == nil){
420 			wunlock(&a->fs->elk);
421 			fprint(2, "archThread: superGet: %r\n");
422 			sleep(60*1000);
423 			continue;
424 		}
425 		super.current = NilBlock;
426 		memmove(super.last, p.score, VtScoreSize);
427 		superPack(&super, b->data);
428 		blockDirty(b);
429 		blockPut(b);
430 		wunlock(&a->fs->elk);
431 
432 		consPrint("archive vac:%V\n", p.score);
433 	}
434 
435 Done:
436 	a->ref--;
437 	rwakeup(&a->die);
438 	qunlock(&a->lk);
439 }
440 
441 void
442 archKick(Arch *a)
443 {
444 	if(a == nil){
445 		fprint(2, "warning: archKick nil\n");
446 		return;
447 	}
448 	qlock(&a->lk);
449 	rwakeup(&a->starve);
450 	qunlock(&a->lk);
451 }