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Remove the concept of recursive vnode locks by eliminating 

vn_setrecurse(), vn_restorerecurse() and LK_CANRECURSE.
Welcome to 5.99.31

Discussed on tech-kern.
This commit is contained in:
hannken 2010-06-18 16:29:01 +00:00
parent 339c26b8f0
commit 2c090918c7
10 changed files with 32 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
distrib/sets/lists/comp/mi
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@ -1,4 +1,4 @@
# $NetBSD: mi,v 1.1467 2010/06/18 04:21:22 mrg Exp $
# $NetBSD: mi,v 1.1468 2010/06/18 16:29:01 hannken Exp $
#
# Note: don't delete entries from here - mark them as "obsolete" instead.
#
@ -9880,8 +9880,8 @@
./usr/share/man/cat9/vn_poll.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_rdwr.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_read.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_restorerecurse.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_setrecurse.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_restorerecurse.0 comp-sys-catman obsolete
./usr/share/man/cat9/vn_setrecurse.0 comp-sys-catman obsolete
./usr/share/man/cat9/vn_start_write.0 comp-obsolete obsolete
./usr/share/man/cat9/vn_stat.0 comp-sys-catman .cat
./usr/share/man/cat9/vn_statfile.0 comp-sys-catman .cat
@ -15582,8 +15582,8 @@
./usr/share/man/html9/vn_poll.html comp-sys-htmlman html
./usr/share/man/html9/vn_rdwr.html comp-sys-htmlman html
./usr/share/man/html9/vn_read.html comp-sys-htmlman html
./usr/share/man/html9/vn_restorerecurse.html comp-sys-htmlman html
./usr/share/man/html9/vn_setrecurse.html comp-sys-htmlman html
./usr/share/man/html9/vn_restorerecurse.html comp-sys-htmlman obsolete
./usr/share/man/html9/vn_setrecurse.html comp-sys-htmlman obsolete
./usr/share/man/html9/vn_stat.html comp-sys-htmlman html
./usr/share/man/html9/vn_statfile.html comp-sys-htmlman html
./usr/share/man/html9/vn_write.html comp-sys-htmlman html
@ -21537,8 +21537,8 @@
./usr/share/man/man9/vn_poll.9 comp-sys-man .man
./usr/share/man/man9/vn_rdwr.9 comp-sys-man .man
./usr/share/man/man9/vn_read.9 comp-sys-man .man
./usr/share/man/man9/vn_restorerecurse.9 comp-sys-man .man
./usr/share/man/man9/vn_setrecurse.9 comp-sys-man .man
./usr/share/man/man9/vn_restorerecurse.9 comp-sys-man obsolete
./usr/share/man/man9/vn_setrecurse.9 comp-sys-man obsolete
./usr/share/man/man9/vn_start_write.9 comp-obsolete obsolete
./usr/share/man/man9/vn_stat.9 comp-sys-man .man
./usr/share/man/man9/vn_statfile.9 comp-sys-man .man

3
doc/CHANGES
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@ -1,4 +1,4 @@
# LIST OF CHANGES FROM LAST RELEASE: <$Revision: 1.1404 $>
# LIST OF CHANGES FROM LAST RELEASE: <$Revision: 1.1405 $>
#
#
# [Note: This file does not mention every change made to the NetBSD source tree.
@ -633,3 +633,4 @@ Changes from NetBSD 5.0 to NetBSD 6.0:
ofppc: Support Gigabit Ethernet Controller for MV64361 on PegasosII
by mvgbe@gt. [kiyohara 20100609]
arm: Added support for Cortex-A8 CPUs. [jmcneill 20100616]
vnsubr(9): Remove recursive vnode locks. [hannken 20100618]

4
share/man/man9/Makefile
View File

@ -1,4 +1,4 @@
# $NetBSD: Makefile,v 1.332 2010/06/08 05:40:27 jruoho Exp $
# $NetBSD: Makefile,v 1.333 2010/06/18 16:29:01 hannken Exp $
# Makefile for section 9 (kernel function and variable) manual pages.
@ -868,9 +868,7 @@ MLINKS+=vnsubr.9 vn_bwrite.9 \
vnsubr.9 vn_lock.9 \
vnsubr.9 vn_markexec.9 \
vnsubr.9 vn_marktext.9 \
vnsubr.9 vn_restorerecurse.9 \
vnsubr.9 vn_rdwr.9 \
vnsubr.9 vn_setrecurse.9 \
vnsubr.9 vn_stat.9 \
vnsubr.9 vn_open.9 \
vnsubr.9 vn_writechk.9

24
share/man/man9/vnsubr.9
View File

@ -1,4 +1,4 @@
.\" $NetBSD: vnsubr.9,v 1.38 2009/06/02 18:09:34 jnemeth Exp $
.\" $NetBSD: vnsubr.9,v 1.39 2010/06/18 16:29:01 hannken Exp $
.\"
.\" Copyright (c) 2001, 2005, 2006 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -27,7 +27,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd June 2, 2009
.Dd June 18, 2010
.Dt VNSUBR 9
.Os
.Sh NAME
@ -40,8 +40,6 @@
.Nm vn_markexec ,
.Nm vn_marktext ,
.Nm vn_rdwr ,
.Nm vn_restorerecurse ,
.Nm vn_setrecurse ,
.Nm vn_open ,
.Nm vn_stat ,
.Nm vn_writechk
@ -64,10 +62,6 @@
.Fn vn_markexec "struct vnode *vp"
.Ft void
.Fn vn_marktext "struct vnode *vp"
.Ft u_int
.Fn vn_setrecurse "struct vnode *vp"
.Ft void
.Fn vn_restorerecurse "struct vnode *vp" "u_int flags"
.Ft int
.Fn vn_open "struct nameidata *ndp" "int fmode" "int cmode"
.Ft int
@ -155,20 +149,6 @@ as containing executable code of a running process.
Common code to mark the vnode
.Fa vp
as being the text of a running process.
.It Fn vn_setrecurse "vp"
Common code to enable
.Dv LK_CANRECURSE
on the vnode lock for vnode
.Fa vp .
.Fn vn_setrecurse
returns the new
.Xr lockmgr 9
flags after the update.
.It Fn vn_restorerecurse "vp" "flags"
Common code to restore the vnode lock flags for the vnode
.Fa vp .
It is called when done with
.Fn vn_setrecurse .
.It Fn vn_open "ndp" "fmode" "cmode"
Common code for vnode open operations.
The pathname is described in the nameidata pointer (see

8
sys/fs/unionfs/unionfs_subr.c
View File

@ -473,7 +473,6 @@ unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp)
static void
unionfs_node_update(struct unionfs_node *unp, struct vnode *uvp)
{
int count, lockcnt;
struct vnode *vp;
struct vnode *lvp;
@ -485,13 +484,8 @@ unionfs_node_update(struct unionfs_node *unp, struct vnode *uvp)
*/
mutex_enter(&vp->v_interlock);
unp->un_uppervp = uvp;
lockcnt = lvp->v_lock.vl_recursecnt +
rw_write_held(&lvp->v_lock.vl_lock);
if (lockcnt <= 0)
panic("unionfs: no exclusive lock");
KASSERT(rw_write_held(&lvp->v_lock.vl_lock));
mutex_exit(&vp->v_interlock);
for (count = 1; count < lockcnt; count++)
vn_lock(uvp, LK_EXCLUSIVE | LK_CANRECURSE | LK_RETRY);
}
/*

40
sys/kern/vfs_subr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: vfs_subr.c,v 1.404 2010/06/06 08:01:31 hannken Exp $ */
/* $NetBSD: vfs_subr.c,v 1.405 2010/06/18 16:29:02 hannken Exp $ */
/*-
* Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008 The NetBSD Foundation, Inc.
@ -91,7 +91,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.404 2010/06/06 08:01:31 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.405 2010/06/18 16:29:02 hannken Exp $");
#include "opt_ddb.h"
#include "opt_compat_netbsd.h"
@ -2738,11 +2738,11 @@ vprint(const char *label, struct vnode *vp)
printf("%s: ", label);
printf("vnode @ %p, flags (%s)\n\ttag %s(%d), type %s(%d), "
"usecount %d, writecount %d, holdcount %d\n"
"\tfreelisthd %p, mount %p, data %p lock %p recursecnt %d\n",
"\tfreelisthd %p, mount %p, data %p lock %p\n",
vp, bf, ARRAY_PRINT(vp->v_tag, vnode_tags), vp->v_tag,
ARRAY_PRINT(vp->v_type, vnode_types), vp->v_type,
vp->v_usecount, vp->v_writecount, vp->v_holdcnt,
vp->v_freelisthd, vp->v_mount, vp->v_data, vl, vl->vl_recursecnt);
vp->v_freelisthd, vp->v_mount, vp->v_data, vl);
if (vp->v_data != NULL) {
printf("\t");
VOP_PRINT(vp);
@ -2928,40 +2928,24 @@ int
vlockmgr(struct vnlock *vl, int flags)
{
KASSERT((flags & ~(LK_CANRECURSE | LK_NOWAIT | LK_TYPE_MASK)) == 0);
KASSERT((flags & ~(LK_NOWAIT | LK_TYPE_MASK)) == 0);
switch (flags & LK_TYPE_MASK) {
switch (flags & (LK_NOWAIT | LK_TYPE_MASK)) {
case LK_SHARED:
if (rw_tryenter(&vl->vl_lock, RW_READER)) {
return 0;
}
if ((flags & LK_NOWAIT) != 0) {
return EBUSY;
}
rw_enter(&vl->vl_lock, RW_READER);
return 0;
case LK_SHARED | LK_NOWAIT:
return rw_tryenter(&vl->vl_lock, RW_READER) ? 0 : EBUSY;
case LK_EXCLUSIVE:
if (rw_tryenter(&vl->vl_lock, RW_WRITER)) {
return 0;
}
if ((vl->vl_canrecurse || (flags & LK_CANRECURSE) != 0) &&
rw_write_held(&vl->vl_lock)) {
vl->vl_recursecnt++;
return 0;
}
if ((flags & LK_NOWAIT) != 0) {
return EBUSY;
}
rw_enter(&vl->vl_lock, RW_WRITER);
return 0;
case LK_EXCLUSIVE | LK_NOWAIT:
return rw_tryenter(&vl->vl_lock, RW_WRITER) ? 0 : EBUSY;
case LK_RELEASE:
if (vl->vl_recursecnt != 0) {
KASSERT(rw_write_held(&vl->vl_lock));
vl->vl_recursecnt--;
return 0;
}
rw_exit(&vl->vl_lock);
return 0;

29
sys/kern/vfs_vnops.c
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@ -1,4 +1,4 @@
/* $NetBSD: vfs_vnops.c,v 1.172 2010/06/06 08:01:31 hannken Exp $ */
/* $NetBSD: vfs_vnops.c,v 1.173 2010/06/18 16:29:02 hannken Exp $ */
/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.172 2010/06/06 08:01:31 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.173 2010/06/18 16:29:02 hannken Exp $");
#include "veriexec.h"
@ -772,8 +772,7 @@ vn_lock(struct vnode *vp, int flags)
|| (vp->v_iflag & VI_ONWORKLST) != 0);
#endif
KASSERT((flags &
~(LK_INTERLOCK|LK_SHARED|LK_EXCLUSIVE|LK_NOWAIT|LK_RETRY|
LK_CANRECURSE))
~(LK_INTERLOCK|LK_SHARED|LK_EXCLUSIVE|LK_NOWAIT|LK_RETRY))
== 0);
#ifdef DIAGNOSTIC
@ -821,28 +820,6 @@ vn_closefile(file_t *fp)
return vn_close(fp->f_data, fp->f_flag, fp->f_cred);
}
/*
* Enable LK_CANRECURSE on lock. Return prior status.
*/
u_int
vn_setrecurse(struct vnode *vp)
{
atomic_inc_uint(&vp->v_lock.vl_canrecurse);
return 0;
}
/*
* Called when done with locksetrecurse.
*/
void
vn_restorerecurse(struct vnode *vp, u_int flags)
{
atomic_dec_uint(&vp->v_lock.vl_canrecurse);
}
/*
* Simplified in-kernel wrapper calls for extended attribute access.
* Both calls pass in a NULL credential, authorizing a "kernel" access.

3
sys/sys/lock.h
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@ -1,4 +1,4 @@
/* $NetBSD: lock.h,v 1.83 2008/04/28 20:24:10 martin Exp $ */
/* $NetBSD: lock.h,v 1.84 2010/06/18 16:29:02 hannken Exp $ */
/*-
* Copyright (c) 1999, 2000, 2006, 2007 The NetBSD Foundation, Inc.
@ -80,7 +80,6 @@
#define LK_EXCLOTHER 0x00000008 /* other process holds lock */
#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
#define LK_CANRECURSE 0x00000040 /* this may be recursive lock attempt */
#define LK_INTERLOCK 0x00010000 /* unlock passed simple lock after
getting lk_interlock */
#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */

4
sys/sys/param.h
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@ -1,4 +1,4 @@
/* $NetBSD: param.h,v 1.365 2010/06/06 08:01:32 hannken Exp $ */
/* $NetBSD: param.h,v 1.366 2010/06/18 16:29:02 hannken Exp $ */
/*-
* Copyright (c) 1982, 1986, 1989, 1993
@ -63,7 +63,7 @@
* 2.99.9 (299000900)
*/
#define __NetBSD_Version__ 599003000 /* NetBSD 5.99.30 */
#define __NetBSD_Version__ 599003100 /* NetBSD 5.99.31 */
#define __NetBSD_Prereq__(M,m,p) (((((M) * 100000000) + \
(m) * 1000000) + (p) * 100) <= __NetBSD_Version__)

6
sys/sys/vnode.h
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@ -1,4 +1,4 @@
/* $NetBSD: vnode.h,v 1.219 2010/06/06 08:01:32 hannken Exp $ */
/* $NetBSD: vnode.h,v 1.220 2010/06/18 16:29:02 hannken Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@ -124,8 +124,6 @@ TAILQ_HEAD(vnodelst, vnode);
struct vnlock {
krwlock_t vl_lock;
u_int vl_canrecurse;
u_int vl_recursecnt;
};
/*
@ -616,8 +614,6 @@ int vn_rdwr(enum uio_rw, struct vnode *, void *, int, off_t, enum uio_seg,
int, kauth_cred_t, size_t *, struct lwp *);
int vn_readdir(struct file *, char *, int, u_int, int *, struct lwp *,
off_t **, int *);
void vn_restorerecurse(struct vnode *, u_int);
u_int vn_setrecurse(struct vnode *);
int vn_stat(struct vnode *, struct stat *);
int vn_kqfilter(struct file *, struct knote *);
int vn_writechk(struct vnode *);