ref: e51c4bc6e493a9cd0d9e9d7f1d24c57ae77bab65
dir: /sys/src/cmd/venti/srv/lump.c/
#include "stdinc.h" #include "dat.h" #include "fns.h" int syncwrites = 0; int queuewrites = 0; int writestodevnull = 0; int verifywrites = 0; static Packet *readilump(Lump *u, IAddr *ia, u8int *score); /* * Some of this logic is duplicated in hdisk.c */ Packet* readlump(u8int *score, int type, u32int size, int *cached) { Lump *u; Packet *p; IAddr ia; u32int n; trace(TraceLump, "readlump enter"); /* qlock(&stats.lock); stats.lumpreads++; qunlock(&stats.lock); */ if(scorecmp(score, zeroscore) == 0) return packetalloc(); u = lookuplump(score, type); if(u->data != nil){ trace(TraceLump, "readlump lookuplump hit"); if(cached) *cached = 1; n = packetsize(u->data); if(n > size){ seterr(EOk, "read too small: asked for %d need at least %d", size, n); putlump(u); return nil; } p = packetdup(u->data, 0, n); putlump(u); return p; } if(cached) *cached = 0; if(lookupscore(score, type, &ia) < 0){ /* ZZZ place to check for someone trying to guess scores */ seterr(EOk, "no block with score %V/%d exists", score, type); putlump(u); return nil; } if(ia.size > size){ seterr(EOk, "read too small 1: asked for %d need at least %d", size, ia.size); putlump(u); return nil; } trace(TraceLump, "readlump readilump"); p = readilump(u, &ia, score); putlump(u); trace(TraceLump, "readlump exit"); return p; } /* * save away a lump, and return it's score. * doesn't store duplicates, but checks that the data is really the same. */ int writelump(Packet *p, u8int *score, int type, u32int creator, uint ms) { Lump *u; int ok; /* qlock(&stats.lock); stats.lumpwrites++; qunlock(&stats.lock); */ packetsha1(p, score); if(packetsize(p) == 0 || writestodevnull==1){ packetfree(p); return 0; } u = lookuplump(score, type); if(u->data != nil){ ok = 0; if(packetcmp(p, u->data) != 0){ uchar nscore[VtScoreSize]; packetsha1(u->data, nscore); if(scorecmp(u->score, score) != 0) seterr(EStrange, "lookuplump returned bad score %V not %V", u->score, score); else if(scorecmp(u->score, nscore) != 0) seterr(EStrange, "lookuplump returned bad data %V not %V", nscore, u->score); else seterr(EStrange, "score collision %V", score); ok = -1; } packetfree(p); putlump(u); return ok; } if(writestodevnull==2){ packetfree(p); return 0; } if(queuewrites) return queuewrite(u, p, creator, ms); ok = writeqlump(u, p, creator, ms); putlump(u); return ok; } int writeqlump(Lump *u, Packet *p, int creator, uint ms) { ZBlock *flat; Packet *old; IAddr ia; int ok; if(lookupscore(u->score, u->type, &ia) == 0){ if(verifywrites == 0){ /* assume the data is here! */ packetfree(p); ms = msec() - ms; addstat2(StatRpcWriteOld, 1, StatRpcWriteOldTime, ms); return 0; } /* * if the read fails, * assume it was corrupted data and store the block again */ old = readilump(u, &ia, u->score); if(old != nil){ ok = 0; if(packetcmp(p, old) != 0){ uchar nscore[VtScoreSize]; packetsha1(old, nscore); if(scorecmp(u->score, nscore) != 0) seterr(EStrange, "readilump returned bad data %V not %V", nscore, u->score); else seterr(EStrange, "score collision %V", u->score); ok = -1; } packetfree(p); packetfree(old); ms = msec() - ms; addstat2(StatRpcWriteOld, 1, StatRpcWriteOldTime, ms); return ok; } logerr(EAdmin, "writelump: read %V failed, rewriting: %r\n", u->score); } flat = packet2zblock(p, packetsize(p)); ok = storeclump(mainindex, flat, u->score, u->type, creator, &ia); freezblock(flat); if(ok == 0) insertlump(u, p); else packetfree(p); if(syncwrites){ flushdcache(); flushicache(); flushdcache(); } ms = msec() - ms; addstat2(StatRpcWriteNew, 1, StatRpcWriteNewTime, ms); return ok; } static Packet* readilump(Lump *u, IAddr *ia, u8int *score) { Arena *arena; ZBlock *zb; Packet *p, *pp; Clump cl; u64int aa; u8int sc[VtScoreSize]; trace(TraceLump, "readilump enter"); arena = amapitoa(mainindex, ia->addr, &aa); if(arena == nil){ trace(TraceLump, "readilump amapitoa failed"); return nil; } trace(TraceLump, "readilump loadclump"); zb = loadclump(arena, aa, ia->blocks, &cl, sc, paranoid); if(zb == nil){ trace(TraceLump, "readilump loadclump failed"); return nil; } if(ia->size != cl.info.uncsize){ seterr(EInconsist, "index and clump size mismatch"); freezblock(zb); return nil; } if(ia->type != cl.info.type){ seterr(EInconsist, "index and clump type mismatch"); freezblock(zb); return nil; } if(scorecmp(score, sc) != 0){ seterr(ECrash, "score mismatch"); freezblock(zb); return nil; } trace(TraceLump, "readilump success"); p = zblock2packet(zb, cl.info.uncsize); freezblock(zb); pp = packetdup(p, 0, packetsize(p)); trace(TraceLump, "readilump insertlump"); insertlump(u, pp); trace(TraceLump, "readilump exit"); return p; }