ref: c8b187f9db503465460d8bafa2d7a758bbcf59ca
dir: /liblogfs/sweep.c/
#include "logfsos.h" #include "logfs.h" #include "local.h" enum { ThrowAway, Keep, Repack, Error, }; #define setaction(a) if(*actionp < (a)) *actionp = a #define REPACK setaction(Repack) #define KEEP setaction(Keep) #define OPTCOPYEX(name, etag, stag) \ if(e->etag != s->stag) { \ s->stag = e->etag; \ REPACK; \ } #define OPTSTRCOPYEX(name, etag, stag) \ if(strcmp(e->etag, s->stag) != 0) { \ s->stag = e->etag; \ REPACK; \ } #define OPTCOPY(name, tag, sunion) OPTCOPYEX(name, tag, u.sunion.tag) #define OPTSTRCOPY(name, tag, sunion) OPTSTRCOPYEX(name, tag, u.sunion.tag) static char * sweepcreate(LogfsServer *server, LogMessage *s, int *actionp) { Entry *pe, *e; e = logfspathmapfinde(server->pathmap, s->u.create.newpath); if(e == nil) /* file no longer exists */ return nil; pe = logfspathmapfinde(server->pathmap, s->path); if(pe == nil) /* file exists but parent doesn't - not good, but can continue */ return "parent missing"; if((pe->perm & DMDIR) == 0 || (e->perm & DMDIR) != (s->u.create.perm & DMDIR)) /* parent must be a directory, and * the directory mode cannot change */ return logfseinternal; if((e->perm & DMDIR) == 0) { OPTCOPYEX("cvers", u.file.cvers, u.create.cvers); } OPTSTRCOPY("name", name, create); OPTCOPY("mtime", mtime, create); OPTCOPY("perm", perm, create); OPTSTRCOPY("uid", uid, create); OPTSTRCOPY("gid", gid, create); KEEP; return nil; } static char * sweepwrite(LogfsServer *server, LogMessage *s, int readoffset, Entry **ep, int *trimp, int *actionp) { Entry *e; Extent extent; Extent *ext; *ep = nil; e = logfspathmapfinde(server->pathmap, s->path); if(e == nil) /* gone, gone */ return nil; if(e->perm & DMDIR) return logfseinternal; if(e->u.file.cvers != s->u.write.cvers) /* trunced more recently */ return nil; extent.min = s->u.write.offset; extent.max = extent.min + s->u.write.count; extent.flashaddr = s->u.write.flashaddr; ext = logfsextentlistmatch(e->u.file.extent, &extent); if(ext == nil) return nil; if(s->u.write.data) { /* * trim the front of the data so that when fixing up extents, * flashaddr refers to the first byte */ int offset; logfsflashaddr2o(server, ext->flashaddr, &offset); *trimp = offset - readoffset; *ep = e; } KEEP; return nil; } typedef struct FixupState { LogfsServer *server; int oldoffset; u32 newflashaddr; } FixupState; static int fixup(void *magic, Extent *e) { FixupState *state = magic; int offset; logfsflashaddr2o(state->server, e->flashaddr, &offset); e->flashaddr = state->newflashaddr + (offset - state->oldoffset); return 1; } static char * sweepblock(LogfsServer *server, uchar *buf) { char *errmsg; LogSegment *active = server->activelog; LogSegment *swept = server->sweptlog; int pagesize, ppb, page; LogfsLowLevel *ll = server->ll; LogfsLowLevelReadResult llrr; int markedbad; long oblock; if(active == nil) return nil; if(swept == nil) { errmsg = logfslogsegmentnew(server, loggensucc(active->gen), &server->sweptlog); if(errmsg) return errmsg; swept = server->sweptlog; } /* * if this is last block in the active log, flush it, so that the read of the last page works */ if(active->unsweptblockindex == active->curblockindex) logfslogsegmentflush(server, 1); ppb = (1 << ll->l2pagesperblock); pagesize = (1 << ll->l2pagesize); for(page = 0; page < ppb; page++) { uchar *p, *bufend; errmsg = (*ll->readpagerange)(ll, buf, active->blockmap[active->unsweptblockindex], page, 0, pagesize, &llrr); if(errmsg) goto fail; if(llrr != LogfsLowLevelReadResultOk) logfsserverreplacelogblock(server, active, active->unsweptblockindex); p = buf; if(*p == 0xff) break; bufend = p + pagesize; while(p < bufend) { int action; uint size; LogMessage s; Entry *e; int trim; size = logfsconvM2S(p, bufend - p, &s); if(size == 0) return "parse failure"; if(server->trace > 1) { print("A>> "); logfsdumpS(&s); print("\n"); } if(s.type == LogfsLogTend) break; action = ThrowAway; switch(s.type) { case LogfsLogTstart: break; case LogfsLogTcreate: errmsg = sweepcreate(server, &s, &action); break; case LogfsLogTremove: /* always obsolete; might check that path really doesn't exist */ break; case LogfsLogTtrunc: /* always obsolete, unless collecting out of order */ break; case LogfsLogTwrite: errmsg = sweepwrite(server, &s, s.u.write.data ? s.u.write.data - buf : 0, &e, &trim, &action); break; case LogfsLogTwstat: /* always obsolete, unless collecting out of order */ break; default: return "bad tag in log page"; } if(action == Error) return errmsg; if(errmsg) print("bad sweep: %s\n", errmsg); if(action == Keep) action = Repack; /* input buffer has been wrecked, so can't just copy it */ if(action == Keep) { /* write 'size' bytes to log */ errmsg = logfslogbytes(server, 0, p, size); if(errmsg) goto fail; } else if(action == Repack) { /* TODO - handle writes */ if(s.type == LogfsLogTwrite && s.u.write.data) { FixupState state; errmsg = logfslogwrite(server, 0, s.path, s.u.write.offset + trim, s.u.write.count - trim, s.u.write.mtime, s.u.write.cvers, s.u.write.muid, s.u.write.data + trim, &state.newflashaddr); if(errmsg == nil && s.u.write.data != nil) { Extent extent; /* TODO - deal with a failure to write the changes */ state.oldoffset = s.u.write.data - buf + trim; state.server = server; extent.min = s.u.write.offset; extent.max = extent.min + s.u.write.count; extent.flashaddr = s.u.write.flashaddr; logfsextentlistmatchall(e->u.file.extent, fixup, &state, &extent); } } else errmsg = logfslog(server, 0, &s); if(errmsg) goto fail; } p += size; } } /* * this log block is no longer needed */ oblock = active->blockmap[active->unsweptblockindex++]; errmsg = logfsbootfettleblock(server->lb, oblock, LogfsTnone, ~0, &markedbad); if(errmsg) goto fail; if(active->unsweptblockindex > active->curblockindex) { /* * the activelog is now empty, so make the sweptlog the active one */ logfslogsegmentfree(&active); server->activelog = swept; server->sweptlog = nil; swept->dirty = 0; } return nil; fail: return errmsg; } char * logfsserverlogsweep(LogfsServer *server, int justone, int *didsomething) { uchar *buf; char *errmsg; /* * TODO - is it even worth doing? */ *didsomething = 0; if(!server->activelog->dirty) return nil; buf = logfsrealloc(nil, (1 << server->ll->l2pagesize)); if(buf == nil) return Enomem; errmsg = nil; while(server->activelog->unsweptblockindex <= server->activelog->curblockindex) { errmsg = sweepblock(server, buf); if(errmsg) break; if(server->sweptlog == nil || justone) break; } logfsfreemem(buf); *didsomething = 1; return errmsg; }