Author: kib
Date: Sun May 31 14:54:20 2009
New Revision: 193173
URL: http://svn.freebsd.org/changeset/base/193173
Log:
Do not drop vnode interlock in null_checkvp(). null_lock() verifies that
v_data is not-null before calling NULLVPTOLOWERVP(), and dropping the
interlock allows for reclaim to clean v_data and free the memory.
While there, remove unneeded semicolons and convert the infinite loops
to panics. I have a will to remove null_checkvp() altogether, or leave
it as a trivial stub, but not now.
Reported and tested by: pho
Modified:
head/sys/fs/nullfs/null_subr.c
Modified: head/sys/fs/nullfs/null_subr.c
==============================================================================
--- head/sys/fs/nullfs/null_subr.c Sun May 31 14:52:45 2009
(r193172)
+++ head/sys/fs/nullfs/null_subr.c Sun May 31 14:54:20 2009
(r193173)
@@ -269,20 +269,14 @@ null_hashrem(xp)
#ifdef DIAGNOSTIC
-#ifdef KDB
-#define null_checkvp_barrier 1
-#else
-#define null_checkvp_barrier 0
-#endif
-
struct vnode *
null_checkvp(vp, fil, lno)
struct vnode *vp;
char *fil;
int lno;
{
- int interlock = 0;
struct null_node *a = VTONULL(vp);
+
#ifdef notyet
/*
* Can't do this check because vop_reclaim runs
@@ -290,9 +284,8 @@ null_checkvp(vp, fil, lno)
*/
if (vp->v_op != null_vnodeop_p) {
printf ("null_checkvp: on non-null-node\n");
- while (null_checkvp_barrier) /*WAIT*/ ;
panic("null_checkvp");
- };
+ }
#endif
if (a->null_lowervp == NULLVP) {
/* Should never happen */
@@ -301,32 +294,24 @@ null_checkvp(vp, fil, lno)
for (p = (u_long *) a, i = 0; i < 8; i++)
printf(" %lx", p[i]);
printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
panic("null_checkvp");
}
- if (mtx_owned(VI_MTX(vp)) != 0) {
- VI_UNLOCK(vp);
- interlock = 1;
- }
- if (vrefcnt(a->null_lowervp) < 1) {
+ VI_LOCK_FLAGS(a->null_lowervp, MTX_DUPOK);
+ if (a->null_lowervp->v_usecount < 1) {
int i; u_long *p;
printf("vp = %p, unref'ed lowervp\n", (void *)vp);
for (p = (u_long *) a, i = 0; i < 8; i++)
printf(" %lx", p[i]);
printf("\n");
- /* wait for debugger */
- while (null_checkvp_barrier) /*WAIT*/ ;
panic ("null with unref'ed lowervp");
- };
- if (interlock != 0)
- VI_LOCK(vp);
+ }
+ VI_UNLOCK(a->null_lowervp);
#ifdef notyet
printf("null %x/%d -> %x/%d [%s, %d]\n",
NULLTOV(a), vrefcnt(NULLTOV(a)),
a->null_lowervp, vrefcnt(a->null_lowervp),
fil, lno);
#endif
- return a->null_lowervp;
+ return (a->null_lowervp);
}
#endif
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