ref: 1018d7a7091fd5e0433f501a3474cdc3fec322cc
dir: /liblogfs/replace.c/
#include "logfsos.h" #include "logfs.h" #include "local.h" #include "fcall.h" static char * copypages(LogfsServer *server, long newb, long oldb, Pageset copymask, LogfsLowLevelReadResult *llrrp, int *markedbadp) { char *errmsg; int page; LogfsLowLevel *ll; int ppb; int pagesize; uchar *buf; if(copymask == 0) return nil; ll = server->ll; ppb = 1 << ll->l2pagesperblock; pagesize = 1 << ll->l2pagesize; *markedbadp = 0; *llrrp = LogfsLowLevelReadResultOk; errmsg = nil; buf = logfsrealloc(nil, 1 << ll->l2pagesize); if(buf == nil) return Enomem; for(page = ppb - 1; page >= 0; page--) { Pageset m; m = logfsdatapagemask(1, page); if(copymask & m) { LogfsLowLevelReadResult llrr; if(server->trace > 1) print("copypages read page %d\n", page); errmsg = (*ll->readpagerange)(ll, buf, oldb, page, 0, pagesize, &llrr); if(errmsg != nil) break; if(llrr > *llrrp) *llrrp = llrr; if(server->trace > 1) print("copypages write page %d\n", page); errmsg = (*ll->writepage)(ll, buf, newb, page); if(errmsg) { if(strcmp(errmsg, Eio) == 0) { (*ll->markblockbad)(ll, newb); *markedbadp = 1; } break; } if(server->trace > 1) print("copypages end page %d\n", page); } } logfsfreemem(buf); return errmsg; } char * logfsservercopyactivedata(LogfsServer *server, long newb, long oldblockindex, int forcepage0, LogfsLowLevelReadResult *llrrp, int *markedbadp) { LogfsLowLevel *ll = server->ll; ulong newpath; DataBlock *ob; char *errmsg; Pageset copymask; ob = server->datablock + oldblockindex; copymask = ~ob->free; if(forcepage0) copymask |= logfsdatapagemask(1, 0); if(server->trace > 1) print("copyactivedata %ld: (%ld -> %ld)\n", oldblockindex, ob->block, newb); newpath = mkdatapath(dataseqof(ob->path), copygensucc(copygenof(ob->path))); (*ll->setblocktag)(ll, newb, LogfsTdata); (*ll->setblockpath)(ll, newb, newpath); errmsg = copypages(server, newb, ob->block, copymask, llrrp, markedbadp); if(errmsg) return errmsg; /* * anything not copied is now not dirty */ ob->dirty &= copymask; ob->block = newb; ob->path = newpath; return nil; } /* * unconditionally replace a datablock, and mark the old one bad * NB: if page 0 is apparently unused, force it to be copied, and mark * it free and dirty afterwards */ char * logfsserverreplacedatablock(LogfsServer *server, long index) { long newb; LogfsLowLevel *ll = server->ll; newb = logfsfindfreeblock(ll, AllocReasonReplace); /* TODO - recover space by scavenging other blocks, or recycling the log */ while(newb >= 0) { char *errmsg; LogfsLowLevelReadResult llrr; long oldblock; int markedbad; DataBlock *db; db = server->datablock + index; oldblock = db->block; errmsg = logfsservercopyactivedata(server, newb, index, 1, &llrr, &markedbad); if(errmsg) { if(!markedbad) return errmsg; newb = logfsfindfreeblock(ll, AllocReasonReplace); continue; } (*ll->markblockbad)(ll, oldblock); return nil; } return logfsefullreplacing; } char * logfsserverreplacelogblock(LogfsServer *server, LogSegment *seg, long index) { ulong opath; LogfsLowLevel *ll = server->ll; long oldb = seg->blockmap[index]; opath = (*ll->getblockpath)(ll, oldb); for(;;) { long newb; int pages; char *errmsg; LogfsLowLevelReadResult llrr; int markedbad; newb = logfsfindfreeblock(ll, AllocReasonReplace); if(newb < 0) return "full replacing log block"; /* TODO - scavenge data space for a spare block */ (*ll->setblocktag)(ll, newb, LogfsTlog); (*ll->setblockpath)(ll, newb, mklogpath(seg->gen, index, copygensucc(copygenof(opath)))); if(index == seg->curblockindex) pages = seg->curpage; else pages = 1 << server->ll->l2pagesperblock; errmsg = copypages(server, newb, oldb, logfsdatapagemask(pages, 0), &llrr, &markedbad); if(errmsg == nil) { (*ll->markblockbad)(ll, seg->blockmap[index]); seg->blockmap[index] = newb; return nil; } if(!markedbad) return errmsg; } } char * logfsserverreplaceblock(LogfsServer *server, LogSegment *seg, long index) { if(seg) return logfsserverreplacelogblock(server, seg, index); else return logfsserverreplacedatablock(server, index); }