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Change null_hashlock into null_hashmtx, because there is no need for

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lockmgr and this helps to vget() vnode from hash without a race.

Reviewed by:	bp
MFC after:	2 weeks
This commit is contained in:
Semen Ustimenko 2002-06-13 20:18:50 +00:00
parent 08720e34b0
commit 1542003115
1 changed files with 15 additions and 22 deletions
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37
sys/fs/nullfs/null_subr.c
View file

@ -42,6 +42,7 @@
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
@ -65,7 +66,7 @@
static LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
static u_long null_node_hash;
struct lock null_hashlock;
struct mtx null_hashmtx;
static MALLOC_DEFINE(M_NULLFSHASH, "NULLFS hash", "NULLFS hash table");
MALLOC_DEFINE(M_NULLFSNODE, "NULLFS node", "NULLFS vnode private part");
@ -85,7 +86,7 @@ nullfs_init(vfsp)
NULLFSDEBUG("nullfs_init\n"); /* printed during system boot */
null_node_hashtbl = hashinit(NNULLNODECACHE, M_NULLFSHASH, &null_node_hash);
lockinit(&null_hashlock, PVFS, "nullhs", 0, 0);
mtx_init(&null_hashmtx, "nullhs", NULL, MTX_DEF);
return (0);
}
@ -94,10 +95,8 @@ nullfs_uninit(vfsp)
struct vfsconf *vfsp;
{
if (null_node_hashtbl) {
lockdestroy(&null_hashlock);
free(null_node_hashtbl, M_NULLFSHASH);
}
mtx_destroy(&null_hashmtx);
free(null_node_hashtbl, M_NULLFSHASH);
return (0);
}
@ -123,29 +122,24 @@ null_node_find(mp, lowervp)
*/
hd = NULL_NHASH(lowervp);
loop:
lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, td);
mtx_lock(&null_hashmtx);
LIST_FOREACH(a, hd, null_hash) {
if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
vp = NULLTOV(a);
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
mtx_lock(&vp->v_interlock);
mtx_unlock(&null_hashmtx);
/*
* We need vget for the VXLOCK
* stuff, but we don't want to lock
* the lower node.
*/
if (vget(vp, LK_EXCLUSIVE | LK_CANRECURSE, td)) {
printf ("null_node_find: vget failed.\n");
if (vget(vp, LK_EXCLUSIVE | LK_THISLAYER | LK_INTERLOCK, td))
goto loop;
};
/*
* Now we got both vnodes locked, so release the
* lower one.
*/
VOP_UNLOCK(lowervp, 0, td);
return (vp);
}
}
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
mtx_unlock(&null_hashmtx);
return NULLVP;
}
@ -214,7 +208,6 @@ null_node_alloc(mp, lowervp, vpp)
* NULL, then we copy that up and manually lock the new vnode.
*/
lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, td);
vp->v_vnlock = lowervp->v_vnlock;
error = VOP_LOCK(vp, LK_EXCLUSIVE | LK_THISLAYER, td);
if (error)
@ -222,8 +215,9 @@ null_node_alloc(mp, lowervp, vpp)
VREF(lowervp);
hd = NULL_NHASH(lowervp);
mtx_lock(&null_hashmtx);
LIST_INSERT_HEAD(hd, xp, null_hash);
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
mtx_unlock(&null_hashmtx);
return 0;
}
@ -293,11 +287,10 @@ void
null_hashrem(xp)
struct null_node *xp;
{
struct thread *td = curthread; /* XXX */
lockmgr(&null_hashlock, LK_EXCLUSIVE, NULL, td);
mtx_lock(&null_hashmtx);
LIST_REMOVE(xp, null_hash);
lockmgr(&null_hashlock, LK_RELEASE, NULL, td);
mtx_unlock(&null_hashmtx);
}
#ifdef DIAGNOSTIC