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cwfs: handle worm exhaustion more gracefully

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don't deadlock when cwgrow() detects we'r out of worm space
by releasing the cache superblock buffer.

don't allocate space beyond the worm device when dumping by
having slit() check. after cwrecur(), we check if there are
enougth blocks remaining to write the dump date directories
and superblocks.
This commit is contained in:
cinap_lenrek 2017-01-30 23:17:18 +01:00
parent 5171a0ac52
commit d643cf2fe6
1 changed files with 17 additions and 6 deletions
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23
sys/src/cmd/cwfs/cw.c
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@ -55,6 +55,7 @@ struct Cw
* following are cached variables for dumps
*/
Off fsize;
Off wsize;
Off ndump;
int depth;
int all; /* local flag to recur on modified dirs */
@ -440,6 +441,7 @@ cwinit(Device *dev)
h->wsize = l;
cb->flags |= Bmod;
}
cw->wsize = l;
for(m=0; m<h->msize; m++) {
p = getbuf(cw->cdev, h->maddr + m/BKPERBLK, Brd);
@ -768,8 +770,10 @@ cwgrow(Device *dev, Superb *sb, int)
h = (Cache*)cb->iobuf;
ws = h->wsize;
fs = h->fsize;
if(fs >= ws)
if(fs >= ws){
putbuf(cb);
return 0;
}
nfs = fs + ADDFREE;
if(nfs >= ws)
nfs = ws;
@ -1259,6 +1263,10 @@ split(Cw *cw, Iobuf *p, Off addr)
case Cdump1:
case Cwrite:
/* worm full */
if(cw->fsize >= cw->wsize)
break;
/*
* botch.. could be done by relabeling
*/
@ -1269,9 +1277,7 @@ split(Cw *cw, Iobuf *p, Off addr)
break;
}
}
na = cw->fsize;
cw->fsize = na+1;
na = cw->fsize++;
cwio(cw->dev, na, 0, Ogrow);
cwio(cw->dev, na, p->iobuf, Owrite);
cwio(cw->dev, na, 0, Odump);
@ -1523,6 +1529,11 @@ cfsdump(Filsys *fs)
h->cwraddr = rba;
putbuf(p);
if(cw->fsize+50 > cw->wsize){
fprint(2, "dump: worm full after dump\n");
goto done;
}
/*
* ro root
*/
@ -1642,8 +1653,7 @@ found:
s = (Superb*)p->iobuf;
s->last = a;
sba = s->next;
s->next = cw->fsize;
cw->fsize++;
s->next = cw->fsize++;
s->fsize = cw->fsize;
s->roraddr = roa;
@ -1667,6 +1677,7 @@ found:
h->sbaddr = sba;
putbuf(p);
done:
rewalk(cw);
sync("all done");