vfs 3

From: Ted Unangst <tedu(at)Stanford.EDU>
Date: Sun Dec 29 2002 - 21:06:50 EST

This is patch 3. Fix locking for root vnode in kernfs and procfs. Remove a bogus VOP_UNLOCK from kernfs. This is meaningless without real locks, but it's less painful to fix this first. It also fixes a memory leak in procfs_umount. Only affects kernfs and procfs.

diff -ruNX nodiff vfs2/miscfs/kernfs/kernfs_vfsops.c vfs3/miscfs/kernfs/kernfs_vfsops.c
--- vfs2/miscfs/kernfs/kernfs_vfsops.c	Wed Dec 25 09:14:09 2002

+++ vfs3/miscfs/kernfs/kernfs_vfsops.c	Thu Dec 26 08:37:09 2002


@@ -102,7 +102,10 @@
 	struct nameidata *ndp;
 	struct proc *p;
 {

+	int error = 0;


 	size_t size;


+	struct vnode *rvp;

+	struct kern_target *kt;



 #ifdef KERNFS_DIAGNOSTIC
 	printf("kernfs_mount(mp = %p)\n", mp);
@@ -114,7 +117,17 @@
 	if (mp->mnt_flag & MNT_UPDATE)
 		return (EOPNOTSUPP);

+	kt = kernfs_findtarget(".", 1);

+	error = kernfs_allocvp(kt, mp, &rvp);

+	if (error)

+		return (error);

+

+	rvp->v_type = VDIR;

+	rvp->v_flag |= VROOT;


 	mp->mnt_flag |= MNT_LOCAL;


+	mp->mnt_data = (qaddr_t)rvp;


+	vrele(rvp);


 	vfs_getnewfsid(mp);

 	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);

@@ -158,8 +171,12 @@
 #ifdef KERNFS_DIAGNOSTIC

         printf("kernfs_unmount: calling vflush\n");  #endif
- if ((error = vflush(mp, 0, flags)) != 0)
+
+ if ((error = vflush(mp, 0, flags)) != 0) {

 		return (error);

+	}

+

+	mp->mnt_data = 0;



 	return (0);

 }
@@ -169,24 +186,16 @@

 	struct mount *mp;
 	struct vnode **vpp;
 {
-	struct kern_target *kt;
-	int error;


+	struct vnode *vp = (struct vnode *)mp->mnt_data;



 #ifdef KERNFS_DIAGNOSTIC
 	printf("kernfs_root(mp = %p)\n", mp);
 #endif
-	kt = kernfs_findtarget(".", 1);
-	/* this should never happen */
-	if (kt == NULL)
-		panic("kernfs_root: findtarget returned NULL");
-
-	error = kernfs_allocvp(kt, mp, vpp);
-	/* this should never happen */
-	if (error)
-		panic("kernfs_root: couldn't find root");

-	return(0);
-

+	vget(vp, LK_EXCLUSIVE | LK_RETRY, curproc);

+	*vpp = vp;

 }

 int

diff -ruNX nodiff vfs2/miscfs/kernfs/kernfs_vnops.c vfs3/miscfs/kernfs/kernfs_vnops.c
--- vfs2/miscfs/kernfs/kernfs_vnops.c	Wed Dec 25 09:43:26 2002

+++ vfs3/miscfs/kernfs/kernfs_vnops.c	Wed Dec 25 21:50:59 2002


@@ -287,7 +287,6 @@
 	struct kernfs_node *kf = VTOKERN(vp);

 	TAILQ_REMOVE(&kfshead, kf, list);
-	VOP_UNLOCK(vp, 0, p);
 	FREE(vp->v_data, M_TEMP);
 	vp->v_data = 0;
 	return(0);
diff -ruNX nodiff vfs2/miscfs/procfs/procfs.h vfs3/miscfs/procfs/procfs.h
--- vfs2/miscfs/procfs/procfs.h	Wed Dec 25 09:14:09 2002


+++ vfs3/miscfs/procfs/procfs.h	Wed Dec 25 21:57:52 2002

@@ -104,6 +104,7 @@
 struct procfsmount {

 	void *pmnt_exechook;
 	int pmnt_flags;


+	struct vnode *rvp;

 };

 #define VFSTOPROC(mp) ((struct procfsmount *)(mp)->mnt_data)

diff -ruNX nodiff vfs2/miscfs/procfs/procfs_vfsops.c vfs3/miscfs/procfs/procfs_vfsops.c
--- vfs2/miscfs/procfs/procfs_vfsops.c	Wed Dec 25 09:14:09 2002


+++ vfs3/miscfs/procfs/procfs_vfsops.c	Thu Dec 26 08:32:54 2002

@@ -82,6 +82,7 @@
 	size_t size;
 	struct procfsmount *pmnt;
 	struct procfs_args args;


+	struct vnode *rvp;


 	int error;

 	if (UIO_MX & (UIO_MX-1)) {
@@ -102,10 +103,18 @@
 	} else
 		args.flags = 0;

+	error = procfs_allocvp(mp, &rvp, 0, Proot);

+	if (error)

+		return (error);

+	rvp->v_type = VDIR;

+	rvp->v_flag |= VROOT;


 	mp->mnt_flag |= MNT_LOCAL;
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 	pmnt = (struct procfsmount *) malloc(sizeof(struct procfsmount),
 	    M_UFSMNT, M_WAITOK);	/* XXX need new malloc type */


+	pmnt->rvp = rvp;

+

 	mp->mnt_data = (qaddr_t)pmnt;
 	vfs_getnewfsid(mp);

@@ -134,6 +143,7 @@
 	int error;
 	extern int doforce;
 	int flags = 0;


+	struct vnode *rvp = VFSTOPROC(mp)->rvp;



 	if (mntflags & MNT_FORCE) {
 		/* procfs can never be rootfs so don't check for it */
@@ -142,8 +152,15 @@
 		flags |= FORCECLOSE;
 	}

-	if ((error = vflush(mp, 0, flags)) != 0)

+	vrele(rvp);

+

+	if ((error = vflush(mp, 0, flags)) != 0) {


+		vget(rvp, 0, curproc);


 		return (error);

+	}

+

+	free(VFSTOPROC(mp), M_UFSMNT);


+	mp->mnt_data = 0;



 	return (0);

 }
@@ -153,8 +170,13 @@

 	struct mount *mp;
 	struct vnode **vpp;
 {


+	struct vnode *vp = VFSTOPROC(mp)->rvp;

-	return (procfs_allocvp(mp, vpp, 0, Proot));

+	VREF(vp);

+	vn_lock(vp, LK_EXCLUSIVE, curproc);

+	*vpp = vp;

 }

 /* ARGSUSED */

--
"I promise you a police car on every sidewalk."
      - M. Barry, Mayor of Washington, DC

Received on Sun Dec 29 21:59:17 2002