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Date:      Mon, 8 Jun 2009 21:23:54 +0000 (UTC)
From:      Paul Saab <ps@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r193762 - in head/sys: kern sys
Message-ID:  <200906082123.n58LNsdd044147@svn.freebsd.org>
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Author: ps
Date: Mon Jun  8 21:23:54 2009
New Revision: 193762
URL: http://svn.freebsd.org/changeset/base/193762

Log:
  Simply shared vnode locking and extend it to also include fsync.
  Also, in vop_write, no longer assert for exclusive locks on the
  vnode.
  
  Reviewed by:	jhb, kmacy, jeffr

Modified:
  head/sys/kern/vfs_syscalls.c
  head/sys/kern/vfs_vnops.c
  head/sys/kern/vnode_if.src
  head/sys/sys/mount.h

Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c	Mon Jun  8 21:16:06 2009	(r193761)
+++ head/sys/kern/vfs_syscalls.c	Mon Jun  8 21:23:54 2009	(r193762)
@@ -3476,7 +3476,7 @@ fsync(td, uap)
 	struct mount *mp;
 	struct file *fp;
 	int vfslocked;
-	int error;
+	int error, lock_flags;
 
 	AUDIT_ARG(fd, uap->fd);
 	if ((error = getvnode(td->td_proc->p_fd, uap->fd, &fp)) != 0)
@@ -3485,7 +3485,13 @@ fsync(td, uap)
 	vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 	if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
 		goto drop;
-	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+	if (MNT_SHARED_WRITES(mp) ||
+	    ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) {
+		lock_flags = LK_SHARED;
+	} else {
+		lock_flags = LK_EXCLUSIVE;
+	}
+	vn_lock(vp, lock_flags | LK_RETRY);
 	AUDIT_ARG(vnode, vp, ARG_VNODE1);
 	if (vp->v_object != NULL) {
 		VM_OBJECT_LOCK(vp->v_object);

Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c	Mon Jun  8 21:16:06 2009	(r193761)
+++ head/sys/kern/vfs_vnops.c	Mon Jun  8 21:23:54 2009	(r193762)
@@ -376,8 +376,8 @@ vn_rdwr(rw, vp, base, len, offset, segfl
 			    (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
 			    != 0)
 				return (error);
-			if (mp != NULL &&
-			    (mp->mnt_kern_flag & MNTK_SHARED_WRITES)) {
+			if (MNT_SHARED_WRITES(mp) ||
+			    ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) {
 				lock_flags = LK_SHARED;
 			} else {
 				lock_flags = LK_EXCLUSIVE;
@@ -592,7 +592,8 @@ vn_write(fp, uio, active_cred, flags, td
 	    (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
 		goto unlock;
  
-	if (mp != NULL && (mp->mnt_kern_flag & MNTK_SHARED_WRITES) &&
+	if ((MNT_SHARED_WRITES(mp) ||
+	    ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) &&
 	    (flags & FOF_OFFSET) != 0) {
 		lock_flags = LK_SHARED;
 	} else {

Modified: head/sys/kern/vnode_if.src
==============================================================================
--- head/sys/kern/vnode_if.src	Mon Jun  8 21:16:06 2009	(r193761)
+++ head/sys/kern/vnode_if.src	Mon Jun  8 21:23:54 2009	(r193762)
@@ -197,7 +197,7 @@ vop_read {
 };
 
 
-%% write	vp	E E E
+%% write	vp	L L L
 %! write	pre	VOP_WRITE_PRE
 %! write	post	VOP_WRITE_POST
 

Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h	Mon Jun  8 21:16:06 2009	(r193761)
+++ head/sys/sys/mount.h	Mon Jun  8 21:23:54 2009	(r193762)
@@ -336,6 +336,9 @@ void          __mnt_vnode_markerfree(str
 #define MNTK_LOOKUP_SHARED	0x40000000 /* FS supports shared lock lookups */
 #define	MNTK_NOKNOTE	0x80000000	/* Don't send KNOTEs from VOP hooks */
 
+#define	MNT_SHARED_WRITES(mp) (((mp) != NULL) && 	\
+				((mp)->mnt_kern_flag & MNTK_SHARED_WRITES))
+
 /*
  * Sysctl CTL_VFS definitions.
  *

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