code: mafs

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fixed the deadlock while getting a buffer and flush on close

--- a/9p.c

+++ b/9p.c

@@ -90,12 +90,17 @@

 		}

 		qunlock(&tlock);

 	}

-/*	dbuf = getmetachk(((Aux*)fid->aux)->dblkno,

-						Bwritable, Tdentry, fid->qid.path);

+

+	/* allocate on flush as many as possible */

+	dbuf = getmeta(((Aux*)fid->aux)->dblkno, Bwritable, Bused);

 	if(dbuf != nil){

-		writeallappend(dbuf, (Dentry*)dbuf->new, ((Aux*)fid->aux)->dblkno);

-		putbuf(dbuf, 1);

-	} */

+		if(p->xiobuf != nil &&

+			p->xiobuf[0] == Tdentry &&

+			p->append != nil)

+			flush(p);

+		else

+			putbuf(dbuf, 0);

+	}

 	freeaux(fid->aux);

 }

--- a/dentry.c

+++ b/dentry.c

@@ -1,5 +1,6 @@

 #include	"all.h"

+/* b shoud be wlock'ed */

 s8

 flush(Iobuf *b)

 {

--- a/iobuf.c

+++ b/iobuf.c

@@ -245,17 +245,11 @@

 Another:

 		do{

 			p = s->back;

-			if(p->ref == 0 && canwlock(p)){

-				if(p->ref > 0){

+			if(p->ref == 0 && p->append != nil && canwlock(p)){

+				if(p->ref > 0 || p->append != nil){

 					wunlock(p);

 					goto Another;

 				}

-				/* allocate on flush as many as possible */

-				if(p->xiobuf[0] == Tdentry &&

-					p->append != nil){

-					if(flush(p))

-						goto Another;

-				}

 				if(p->len != len){

 					freememunits(p->xiobuf, p->len);

 					p->xiobuf = allocmemunits(len);

@@ -430,7 +424,7 @@

 		}else if(p->xiobuf[0] > Tdata && p->xiobuf[0] < MAXTAG){

 			/*

 				make the new->ver below the cur->ver so the new gets

-				overwritten the next time instead of a memcpy() to

+				overwritten on the next access instead of a memcpy() to

 				copy the contents over.

 			 */

 			p->new->verd = p->cur->verd-1;