![cinap_lenrek](/assets/img/avatar_default.png)
getdent() introduced a bug as the qid check fails in the case when we walk to DUMPROOTQID, but get ROOTQID in the directory instead. newentry() getblk(..., GBCREATE) caused the whole directory to get dumped until it hit a free slot. we cannot do this because this changes the addresses of Dentries of files but doesnt update the loctree. this caused the bogus walks when we hit a different directory than we expected. what we do now is the following: newentry() was changed to never dump anything. it will just read the directory and return a the address of a free slot or create a new block having space for one. chancreat() then makes a loc in the loctree for the free slot, drops the dirent buffer and calls willmodify() on the new slot. this will dump the block containing the slot (and possible other slots) and updates the loctree to the new version. after that, chancreate() modifies the slot filling the Dentry. there should be no race, as newentry() skips slots that have a loc in the loctree. theres one case where newentry() can dump the block immidiately when it is called from dump. added new parameter for that and documented in the comment. createuserdir() was simplified by just calling chancreat(). to get arround the permission check, a new per channel flag CHFNOPERM was added.
197 lines
3.3 KiB
C
197 lines
3.3 KiB
C
#include <u.h>
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#include <libc.h>
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#include <thread.h>
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#include "dat.h"
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#include "fns.h"
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int
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copydentry(Fs *fs, FLoc *a, Loc *b, char *nname)
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{
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Buf *ba, *bb, *bc;
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Dentry *d;
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int i, rc;
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FLoc c;
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if(!namevalid(nname)){
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werrstr(Einval);
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return -1;
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}
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ba = getbuf(fs->d, a->blk, TDENTRY, 0);
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if(ba == nil)
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return -1;
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bb = getbuf(fs->d, b->blk, TDENTRY, 0);
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if(bb == nil){
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putbuf(ba);
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return -1;
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}
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rc = newentry(fs, b, bb, nname, &c, 1);
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if(rc < 0){
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err1:
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putbuf(bb);
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putbuf(ba);
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return -1;
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}
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bc = getbuf(fs->d, c.blk, TDENTRY, 0);
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if(bc == nil)
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goto err1;
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d = &bc->de[c.deind];
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memcpy(d, &ba->de[a->deind], sizeof(*d));
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strcpy(d->name, nname);
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for(i = 0; i < NDIRECT; i++)
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if(d->db[i] != 0)
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chref(fs, d->db[i], 1);
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for(i = 0; i < NINDIRECT; i++)
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if(d->ib[i] != 0)
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chref(fs, d->ib[i], 1);
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bc->op |= BDELWRI;
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putbuf(bc);
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putbuf(bb);
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putbuf(ba);
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return 0;
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}
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static void
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resetldumped(Fs *fs)
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{
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Loc *l;
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for(l = fs->rootloc->gnext; l != fs->rootloc; l = l->gnext)
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l->flags &= ~LDUMPED;
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}
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int
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fsdump(Fs *fs)
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{
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char buf[20], *p, *e;
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int n, rc;
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Tm *tm;
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Chan *ch, *chh;
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Buf *b;
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wlock(fs);
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tm = localtime(time(0));
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snprint(buf, sizeof(buf), "%.4d", tm->year + 1900);
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ch = chanattach(fs, CHFNOLOCK|CHFDUMP);
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ch->uid = -1;
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if(ch == nil){
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wunlock(fs);
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return -1;
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}
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if(chanwalk(ch, buf) < 0){
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chh = chanclone(ch);
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rc = chancreat(chh, buf, DMDIR|0555, OREAD);
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chanclunk(chh);
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if(rc < 0)
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goto err;
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if(chanwalk(ch, buf) < 0)
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goto err;
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}
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b = getbuf(fs->d, ch->loc->blk, TDENTRY, 0);
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if(b == nil)
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goto err;
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for(n = 0; ; n++){
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e = buf + sizeof(buf);
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p = seprint(buf, e, "%.2d%.2d", tm->mon + 1, tm->mday);
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if(n > 0)
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seprint(p, e, "%d", n);
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rc = findentry(fs, ch->loc, b, buf, nil, 1);
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if(rc < 0)
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goto err;
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if(rc == 0)
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break;
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}
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putbuf(b);
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rc = copydentry(fs, fs->rootloc, ch->loc, buf);
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chanclunk(ch);
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resetldumped(fs);
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wunlock(fs);
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return rc;
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err:
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chanclunk(ch);
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wunlock(fs);
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return -1;
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}
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int
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willmodify(Fs *fs, Loc *l, int nolock)
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{
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Buf *p;
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Loc *m;
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uvlong i, r;
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Dentry *d;
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int rc;
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if((l->flags & LDUMPED) != 0)
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return 1;
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if(!nolock){
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again:
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runlock(fs);
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wlock(fs);
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}
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if(l->next != nil && willmodify(fs, l->next, 1) < 0)
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goto err;
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rc = chref(fs, l->blk, 0);
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if(rc < 0)
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goto err;
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if(rc == 0){
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dprint("hjfs: willmodify: block %lld has refcount 0\n", l->blk);
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werrstr("phase error -- willmodify");
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goto err;
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}
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if(rc == 1)
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goto done;
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p = getbuf(fs->d, l->next->blk, TDENTRY, 0);
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if(p == nil)
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goto err;
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d = getdent(l->next, p);
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if(d != nil) for(i = 0; i < d->size; i++){
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rc = getblk(fs, l->next, p, i, &r, GBREAD);
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if(rc <= 0)
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continue;
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if(r == l->blk)
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goto found;
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}
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phase:
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werrstr("willmodify -- phase error");
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putbuf(p);
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goto err;
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found:
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rc = getblk(fs, l->next, p, i, &r, GBWRITE);
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if(rc < 0){
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putbuf(p);
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goto err;
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}
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if(rc == 0)
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goto phase;
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putbuf(p);
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if(r != l->blk){
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/*
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* block got dumped, update the loctree so locs
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* point to the new block.
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*/
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qlock(&fs->loctree);
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for(m = l->cnext; m != l; m = m->cnext)
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if(m->blk == l->blk)
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m->blk = r;
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l->blk = r;
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qunlock(&fs->loctree);
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}
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done:
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l->flags |= LDUMPED;
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if(!nolock){
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wunlock(fs);
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rlock(fs);
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if(chref(fs, l->blk, 0) != 1)
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goto again;
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}
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return 0;
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err:
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if(!nolock){
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wunlock(fs);
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rlock(fs);
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}
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return -1;
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}
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