svn commit: r202810 - in stable/7/sys: kern sys

[John Baldwin]

Author: jhb
Date: Fri Jan 22 14:44:15 2010
New Revision: 202810
URL: http://svn.freebsd.org/changeset/base/202810

Log:
  MFC 193440,193442,193762,194019:
  - Support shared vnode locks for write operations when the offset is
    provided on filesystems that support it.  This really improves mysql
    + innodb performance on ZFS.
  - When checking for shared writes, use the struct mount returned from
    vn_start_write.
  - Simply shared vnode locking and extend it to also include fsync.
    Also, in vop_write, no longer assert for exclusive locks on the
    vnode.
  - Stop asserting on exclusive locks in fsync since it can now support
    shared vnode locking on ZFS.

Modified:
  stable/7/sys/kern/vfs_syscalls.c
  stable/7/sys/kern/vfs_vnops.c
  stable/7/sys/kern/vnode_if.src
  stable/7/sys/sys/mount.h
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/kern/vfs_syscalls.c
==============================================================================
--- stable/7/sys/kern/vfs_syscalls.c	Fri Jan 22 14:25:17 2010	(r202809)
+++ stable/7/sys/kern/vfs_syscalls.c	Fri Jan 22 14:44:15 2010	(r202810)
@@ -3267,7 +3267,7 @@ 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)
@@ -3276,7 +3276,13 @@ 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, td);
+	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, td);
 	AUDIT_ARG(vnode, vp, ARG_VNODE1);
 	if (vp->v_object != NULL) {
 		VM_OBJECT_LOCK(vp->v_object);

Modified: stable/7/sys/kern/vfs_vnops.c
==============================================================================
--- stable/7/sys/kern/vfs_vnops.c	Fri Jan 22 14:25:17 2010	(r202809)
+++ stable/7/sys/kern/vfs_vnops.c	Fri Jan 22 14:44:15 2010	(r202810)
@@ -370,13 +370,9 @@ 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)) {
-				/*
-				 * XXX See the next comment what should
-				 * be done here too.
-				 */
-				lock_flags = LK_EXCLUSIVE;
+			if (MNT_SHARED_WRITES(mp) ||
+			    ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) {
+				lock_flags = LK_SHARED;
 			} else {
 				lock_flags = LK_EXCLUSIVE;
 			}
@@ -594,15 +590,10 @@ vn_write(fp, uio, active_cred, flags, td
 	    (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
 		goto unlock;
  
-	if (vp->v_mount != NULL &&
-	    (vp->v_mount->mnt_kern_flag & MNTK_SHARED_WRITES) &&
+	if ((MNT_SHARED_WRITES(mp) ||
+	    ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) &&
 	    (flags & FOF_OFFSET) != 0) {
-		/*
-		 * XXX This should be LK_SHARED but the VFS in releng7
-		 * needs some patches before this can be done.
-		 * See the similar comment above.
-		 */
-		lock_flags = LK_EXCLUSIVE;
+		lock_flags = LK_SHARED;
 	} else {
 		lock_flags = LK_EXCLUSIVE;
 	}

Modified: stable/7/sys/kern/vnode_if.src
==============================================================================
--- stable/7/sys/kern/vnode_if.src	Fri Jan 22 14:25:17 2010	(r202809)
+++ stable/7/sys/kern/vnode_if.src	Fri Jan 22 14:44:15 2010	(r202810)
@@ -185,7 +185,7 @@ vop_read {
 };
 
 
-%% write	vp	E E E
+%% write	vp	L L L
 %! write	pre	VOP_WRITE_PRE
 %! write	post	VOP_WRITE_POST
 
@@ -245,7 +245,7 @@ vop_revoke {
 };
 
 
-%% fsync	vp	E E E
+%% fsync	vp	L L L
 
 vop_fsync {
 	IN struct vnode *vp;

Modified: stable/7/sys/sys/mount.h
==============================================================================
--- stable/7/sys/sys/mount.h	Fri Jan 22 14:25:17 2010	(r202809)
+++ stable/7/sys/sys/mount.h	Fri Jan 22 14:44:15 2010	(r202810)
@@ -339,6 +339,9 @@ 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.
  *