Module Name: src
Committed By: riastradh
Date: Fri Oct 19 02:07:23 UTC 2012
Modified Files:
src/sys/kern: vfs_syscalls.c
Log Message:
No, we can't elide the fs-wide rename lock for same-directory rename.
rename("a/b", "a/c") and rename("a/c/x", "a/b/y") will deadlock.
Darn.
To generate a diff of this commit:
cvs rdiff -u -r1.458 -r1.459 src/sys/kern/vfs_syscalls.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/kern/vfs_syscalls.c
diff -u src/sys/kern/vfs_syscalls.c:1.458 src/sys/kern/vfs_syscalls.c:1.459
--- src/sys/kern/vfs_syscalls.c:1.458 Fri Oct 12 02:37:20 2012
+++ src/sys/kern/vfs_syscalls.c Fri Oct 19 02:07:22 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_syscalls.c,v 1.458 2012/10/12 02:37:20 riastradh Exp $ */
+/* $NetBSD: vfs_syscalls.c,v 1.459 2012/10/19 02:07:22 riastradh Exp $ */
/*-
* Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.458 2012/10/12 02:37:20 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.459 2012/10/19 02:07:22 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_fileassoc.h"
@@ -4041,11 +4041,9 @@ do_sys_rename(const char *from, const ch
* Take the vfs rename lock to avoid cross-directory screw cases.
* Nothing is locked currently, so taking this lock is safe.
*/
- if (fdvp != tdvp) {
- error = VFS_RENAMELOCK_ENTER(mp);
- if (error)
- goto abort1;
- }
+ error = VFS_RENAMELOCK_ENTER(mp);
+ if (error)
+ goto abort1;
/*
* Now fdvp, fvp, tdvp, and (if nonnull) tvp are referenced,
@@ -4186,15 +4184,13 @@ do_sys_rename(const char *from, const ch
* So all we have left to do is to drop the rename lock and
* destroy the pathbufs.
*/
- if (fdvp != tdvp)
- VFS_RENAMELOCK_EXIT(mp);
+ VFS_RENAMELOCK_EXIT(mp);
goto out2;
abort3: if ((tvp != NULL) && (tvp != tdvp))
VOP_UNLOCK(tvp);
abort2: VOP_UNLOCK(tdvp);
- if (fdvp != tdvp)
- VFS_RENAMELOCK_EXIT(mp);
+ VFS_RENAMELOCK_EXIT(mp);
abort1: VOP_ABORTOP(tdvp, &tnd.ni_cnd);
vrele(tdvp);
if (tvp != NULL)
