Module Name: src
Committed By: hannken
Date: Sun Feb 16 09:50:25 UTC 2014
Modified Files:
src/sys/fs/union: union_subr.c union_vfsops.c union_vnops.c
Log Message:
Change union_allocvp() to take an unlocked uppervp and to return the
union node unlocked. Another VI_XLOCK hack is gone.
To generate a diff of this commit:
cvs rdiff -u -r1.62 -r1.63 src/sys/fs/union/union_subr.c
cvs rdiff -u -r1.68 -r1.69 src/sys/fs/union/union_vfsops.c
cvs rdiff -u -r1.55 -r1.56 src/sys/fs/union/union_vnops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/union/union_subr.c
diff -u src/sys/fs/union/union_subr.c:1.62 src/sys/fs/union/union_subr.c:1.63
--- src/sys/fs/union/union_subr.c:1.62 Fri Feb 14 08:50:27 2014
+++ src/sys/fs/union/union_subr.c Sun Feb 16 09:50:25 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: union_subr.c,v 1.62 2014/02/14 08:50:27 hannken Exp $ */
+/* $NetBSD: union_subr.c,v 1.63 2014/02/16 09:50:25 hannken Exp $ */
/*
* Copyright (c) 1994
@@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.62 2014/02/14 08:50:27 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.63 2014/02/16 09:50:25 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -291,7 +291,7 @@ union_newsize(struct vnode *vp, off_t up
/*
* allocate a union_node/vnode pair. the vnode is
- * referenced and locked. the new vnode is returned
+ * referenced and unlocked. the new vnode is returned
* via (vpp). (mp) is the mountpoint of the union filesystem,
* (dvp) is the parent directory where the upper layer object
* should exist (but doesn't) and (cnp) is the componentname
@@ -299,7 +299,7 @@ union_newsize(struct vnode *vp, off_t up
* layer object to be created at a later time. (uppervp)
* and (lowervp) reference the upper and lower layer objects
* being mapped. either, but not both, can be nil.
- * if supplied, (uppervp) is locked.
+ * both, if supplied, are unlocked.
* the reference is either maintained in the new union_node
* object which is allocated, or they are vrele'd.
*
@@ -339,11 +339,11 @@ union_allocvp(
voff_t uppersz, lowersz;
dev_t rdev;
u_long hash[3];
- int vflag, iflag, lflag;
+ int vflag, iflag;
int try;
+ bool is_dotdot;
- if (uppervp)
- KASSERT(VOP_ISLOCKED(uppervp) == LK_EXCLUSIVE);
+ is_dotdot = (dvp != NULL && cnp != NULL && (cnp->cn_flags & ISDOTDOT));
if (uppervp == NULLVP && lowervp == NULLVP)
panic("union: unidentifiable allocation");
@@ -396,28 +396,10 @@ loop:
UNIONTOV(un)->v_mount != mp)
continue;
- if (uppervp != NULL &&
- (uppervp == dvp || uppervp == un->un_uppervp))
- /* "." or already locked. */
- lflag = 0;
- else
- lflag = LK_EXCLUSIVE;
vp = UNIONTOV(un);
mutex_enter(vp->v_interlock);
- /*
- * If this node being cleaned out and our caller
- * holds a lock, then ignore it and continue. To
- * allow the cleaning to succeed the current thread
- * must make progress. For a brief time the cache
- * may contain more than one vnode referring to
- * a lower node.
- */
- if ((vp->v_iflag & VI_XLOCK) != 0 && lflag == 0) {
- mutex_exit(vp->v_interlock);
- continue;
- }
mutex_exit(&uhash_lock);
- if (vget(vp, lflag))
+ if (vget(vp, 0))
goto loop;
goto found;
}
@@ -427,9 +409,13 @@ loop:
found:
if (un) {
- KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
- KASSERT(uppervp == NULL ||
- VOP_ISLOCKED(uppervp) == LK_EXCLUSIVE);
+ if (uppervp != dvp) {
+ if (is_dotdot)
+ VOP_UNLOCK(dvp);
+ vn_lock(UNIONTOV(un), LK_EXCLUSIVE | LK_RETRY);
+ if (is_dotdot)
+ vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
+ }
/*
* Save information about the upper layer.
*/
@@ -460,19 +446,23 @@ found:
vrele(lowervp);
}
*vpp = UNIONTOV(un);
+ if (uppervp != dvp)
+ VOP_UNLOCK(*vpp);
return (0);
}
uppersz = lowersz = VNOVAL;
- if (uppervp != NULLVP)
+ if (uppervp != NULLVP) {
+ vn_lock(uppervp, LK_SHARED | LK_RETRY);
if (VOP_GETATTR(uppervp, &va, FSCRED) == 0)
uppersz = va.va_size;
+ VOP_UNLOCK(uppervp);
+ }
if (lowervp != NULLVP) {
vn_lock(lowervp, LK_SHARED | LK_RETRY);
- error = VOP_GETATTR(lowervp, &va, FSCRED);
- VOP_UNLOCK(lowervp);
- if (error == 0)
+ if (VOP_GETATTR(lowervp, &va, FSCRED) == 0)
lowersz = va.va_size;
+ VOP_UNLOCK(lowervp);
}
/*
@@ -483,12 +473,8 @@ found:
error = getnewvnode(VT_UNION, mp, union_vnodeop_p,
svp->v_interlock, vpp);
if (error) {
- if (uppervp) {
- if (dvp == uppervp)
- vrele(uppervp);
- else
- vput(uppervp);
- }
+ if (uppervp)
+ vrele(uppervp);
if (lowervp)
vrele(lowervp);
@@ -501,17 +487,6 @@ found:
if (un1->un_lowervp == lowervp &&
un1->un_uppervp == uppervp &&
UNIONTOV(un1)->v_mount == mp) {
- vp = UNIONTOV(un1);
- mutex_enter(vp->v_interlock);
- /*
- * Ignore nodes being cleaned out.
- * See the cache lookup above.
- */
- if ((vp->v_iflag & VI_XLOCK) != 0) {
- mutex_exit(vp->v_interlock);
- continue;
- }
- mutex_exit(vp->v_interlock);
/*
* Another thread beat us, push back freshly
* allocated vnode and retry.
@@ -552,15 +527,6 @@ found:
un->un_openl = 0;
un->un_cflags = 0;
- if (uppervp == NULL) {
- struct vop_lock_args ap;
-
- ap.a_vp = UNIONTOV(un);
- ap.a_flags = LK_EXCLUSIVE;
- error = genfs_lock(&ap);
- KASSERT(error == 0);
- }
-
mutex_enter(&un->un_lock);
un->un_uppersz = VNOVAL;
un->un_lowersz = VNOVAL;
@@ -1076,10 +1042,10 @@ union_dircache(struct vnode *vp, struct
if (*vpp == NULLVP)
goto out;
- vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
vref(*vpp);
error = union_allocvp(&nvp, vp->v_mount, NULLVP, NULLVP, 0, *vpp, NULLVP, 0);
if (!error) {
+ vn_lock(nvp, LK_EXCLUSIVE | LK_RETRY);
VTOUNION(vp)->un_dircache = 0;
VTOUNION(nvp)->un_dircache = dircache;
}
Index: src/sys/fs/union/union_vfsops.c
diff -u src/sys/fs/union/union_vfsops.c:1.68 src/sys/fs/union/union_vfsops.c:1.69
--- src/sys/fs/union/union_vfsops.c:1.68 Mon Apr 30 22:51:27 2012
+++ src/sys/fs/union/union_vfsops.c Sun Feb 16 09:50:25 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: union_vfsops.c,v 1.68 2012/04/30 22:51:27 rmind Exp $ */
+/* $NetBSD: union_vfsops.c,v 1.69 2014/02/16 09:50:25 hannken Exp $ */
/*
* Copyright (c) 1994 The Regents of the University of California.
@@ -77,7 +77,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.68 2012/04/30 22:51:27 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.69 2014/02/16 09:50:25 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -386,19 +386,21 @@ union_root(struct mount *mp, struct vnod
* Return locked reference to root.
*/
vref(um->um_uppervp);
- vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY);
if (um->um_lowervp)
vref(um->um_lowervp);
error = union_allocvp(vpp, mp, NULL, NULL, NULL,
um->um_uppervp, um->um_lowervp, 1);
if (error) {
- vput(um->um_uppervp);
+ vrele(um->um_uppervp);
if (um->um_lowervp)
vrele(um->um_lowervp);
+ return error;
}
- return (error);
+ vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
+
+ return 0;
}
int
Index: src/sys/fs/union/union_vnops.c
diff -u src/sys/fs/union/union_vnops.c:1.55 src/sys/fs/union/union_vnops.c:1.56
--- src/sys/fs/union/union_vnops.c:1.55 Thu Feb 13 21:05:26 2014
+++ src/sys/fs/union/union_vnops.c Sun Feb 16 09:50:25 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: union_vnops.c,v 1.55 2014/02/13 21:05:26 martin Exp $ */
+/* $NetBSD: union_vnops.c,v 1.56 2014/02/16 09:50:25 hannken Exp $ */
/*
* Copyright (c) 1992, 1993, 1994, 1995
@@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.55 2014/02/13 21:05:26 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.56 2014/02/16 09:50:25 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -467,11 +467,6 @@ start:
vput(lowervp);
goto start;
}
- /*
- * XXX: lock upper node until lookup returns
- * unlocked nodes.
- */
- vn_lock(uppervp, LK_EXCLUSIVE | LK_RETRY);
}
if (uerror) {
if (lowervp != NULLVP) {
@@ -481,6 +476,9 @@ start:
return (uerror);
}
}
+ } else { /* uerror == 0 */
+ if (uppervp != upperdvp)
+ VOP_UNLOCK(uppervp);
}
if (lowervp != NULLVP)
@@ -491,15 +489,12 @@ start:
if (error) {
if (uppervp != NULLVP)
- vput(uppervp);
+ vrele(uppervp);
if (lowervp != NULLVP)
vrele(lowervp);
return error;
}
- if (*ap->a_vpp != dvp)
- VOP_UNLOCK(*ap->a_vpp);
-
return 0;
}
@@ -526,11 +521,8 @@ union_create(void *v)
if (error)
return (error);
- /* XXX: lock upper node until lookup returns unlocked nodes. */
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP, cnp, vp,
NULLVP, 1);
- VOP_UNLOCK(vp);
if (error)
vrele(vp);
return (error);
@@ -579,11 +571,8 @@ union_mknod(void *v)
if (error)
return (error);
- /* XXX: lock upper node until lookup returns unlocked nodes. */
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = union_allocvp(ap->a_vpp, mp, NULLVP, NULLVP,
cnp, vp, NULLVP, 1);
- VOP_UNLOCK(vp);
if (error)
vrele(vp);
return (error);
@@ -1400,11 +1389,8 @@ union_mkdir(void *v)
return (error);
}
- /* XXX: lock upper node until lookup returns unlocked nodes. */
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = union_allocvp(ap->a_vpp, ap->a_dvp->v_mount, ap->a_dvp,
NULLVP, cnp, vp, NULLVP, 1);
- VOP_UNLOCK(vp);
if (error)
vrele(vp);
return (error);
