svn commit: r184600 - head/sys/kern

[John Baldwin]

Author: jhb
Date: Mon Nov  3 20:31:00 2008
New Revision: 184600
URL: http://svn.freebsd.org/changeset/base/184600

Log:
  Use shared vnode locks instead of exclusive vnode locks for the access(),
  chdir(), chroot(), eaccess(), fpathconf(), fstat(), fstatfs(), lseek()
  (when figuring out the current size of the file in the SEEK_END case),
  pathconf(), readlink(), and statfs() system calls.
  
  Submitted by:	ups (mostly)
  Tested by:	pho
  MFC after:	1 month

Modified:
  head/sys/kern/kern_descrip.c
  head/sys/kern/vfs_syscalls.c
  head/sys/kern/vfs_vnops.c

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Mon Nov  3 20:00:35 2008	(r184599)
+++ head/sys/kern/kern_descrip.c	Mon Nov  3 20:31:00 2008	(r184600)
@@ -1241,7 +1241,7 @@ fpathconf(struct thread *td, struct fpat
 	if (vp != NULL) {
 		int vfslocked;
 		vfslocked = VFS_LOCK_GIANT(vp->v_mount);
-		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+		vn_lock(vp, LK_SHARED | LK_RETRY);
 		error = VOP_PATHCONF(vp, uap->name, td->td_retval);
 		VOP_UNLOCK(vp, 0);
 		VFS_UNLOCK_GIANT(vfslocked);

Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c	Mon Nov  3 20:00:35 2008	(r184599)
+++ head/sys/kern/vfs_syscalls.c	Mon Nov  3 20:31:00 2008	(r184600)
@@ -286,8 +286,8 @@ kern_statfs(struct thread *td, char *pat
 	int error;
 	struct nameidata nd;
 
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
-	    pathseg, path, td);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | MPSAFE |
+	    AUDITVNODE1, pathseg, path, td);
 	error = namei(&nd);
 	if (error)
 		return (error);
@@ -368,7 +368,7 @@ kern_fstatfs(struct thread *td, int fd, 
 		return (error);
 	vp = fp->f_vnode;
 	vfslocked = VFS_LOCK_GIANT(vp->v_mount);
-	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+	vn_lock(vp, LK_SHARED | LK_RETRY);
 #ifdef AUDIT
 	AUDIT_ARG(vnode, vp, ARG_VNODE1);
 #endif
@@ -800,8 +800,8 @@ kern_chdir(struct thread *td, char *path
 	struct vnode *vp;
 	int vfslocked;
 
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1 | MPSAFE,
-	    pathseg, path, td);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | AUDITVNODE1 |
+	    MPSAFE, pathseg, path, td);
 	if ((error = namei(&nd)) != 0)
 		return (error);
 	vfslocked = NDHASGIANT(&nd);
@@ -886,8 +886,8 @@ chroot(td, uap)
 	error = priv_check(td, PRIV_VFS_CHROOT);
 	if (error)
 		return (error);
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
-	    UIO_USERSPACE, uap->path, td);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | MPSAFE |
+	    AUDITVNODE1, UIO_USERSPACE, uap->path, td);
 	error = namei(&nd);
 	if (error)
 		goto error;
@@ -1938,7 +1938,7 @@ lseek(td, uap)
 		offset += fp->f_offset;
 		break;
 	case L_XTND:
-		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+		vn_lock(vp, LK_SHARED | LK_RETRY);
 		error = VOP_GETATTR(vp, &vattr, cred);
 		VOP_UNLOCK(vp, 0);
 		if (error)
@@ -2125,8 +2125,8 @@ kern_accessat(struct thread *td, int fd,
 		td->td_ucred = tmpcred;
 	} else
 		cred = tmpcred = td->td_ucred;
-	NDINIT_AT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
-	    pathseg, path, fd, td);
+	NDINIT_AT(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | MPSAFE |
+	    AUDITVNODE1, pathseg, path, fd, td);
 	if ((error = namei(&nd)) != 0)
 		goto out1;
 	vfslocked = NDHASGIANT(&nd);
@@ -2492,8 +2492,8 @@ kern_pathconf(struct thread *td, char *p
 	struct nameidata nd;
 	int error, vfslocked;
 
-	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
-	    pathseg, path, td);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | MPSAFE |
+	    AUDITVNODE1, pathseg, path, td);
 	if ((error = namei(&nd)) != 0)
 		return (error);
 	vfslocked = NDHASGIANT(&nd);
@@ -2568,8 +2568,8 @@ kern_readlinkat(struct thread *td, int f
 	struct nameidata nd;
 	int vfslocked;
 
-	NDINIT_AT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
-	    pathseg, path, fd, td);
+	NDINIT_AT(&nd, LOOKUP, NOFOLLOW | LOCKSHARED | LOCKLEAF | MPSAFE |
+	    AUDITVNODE1, pathseg, path, fd, td);
 
 	if ((error = namei(&nd)) != 0)
 		return (error);

Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c	Mon Nov  3 20:00:35 2008	(r184599)
+++ head/sys/kern/vfs_vnops.c	Mon Nov  3 20:31:00 2008	(r184600)
@@ -673,7 +673,7 @@ vn_statfile(fp, sb, active_cred, td)
 	int error;
 
 	vfslocked = VFS_LOCK_GIANT(vp->v_mount);
-	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+	vn_lock(vp, LK_SHARED | LK_RETRY);
 	error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
 	VOP_UNLOCK(vp, 0);
 	VFS_UNLOCK_GIANT(vfslocked);