From d9c1039158d022977b141a2880fe9724a697de84 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Thu, 10 Apr 2014 14:15:44 +0000
Subject: [PATCH 03/14] Omit needless locking in ffs_vget and ext2fs_vget.

---
 sys/ufs/ext2fs/ext2fs_vfsops.c | 13 +++++--------
 sys/ufs/ffs/ffs_vfsops.c       | 11 ++++-------
 sys/ufs/ufs/ufs_extern.h       |  2 +-
 sys/ufs/ufs/ufs_ihash.c        | 11 +++--------
 4 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/sys/ufs/ext2fs/ext2fs_vfsops.c b/sys/ufs/ext2fs/ext2fs_vfsops.c
index a48f931..a04e51b 100644
--- a/sys/ufs/ext2fs/ext2fs_vfsops.c
+++ b/sys/ufs/ext2fs/ext2fs_vfsops.c
@@ -961,10 +961,8 @@ ext2fs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 	ump = VFSTOUFS(mp);
 	dev = ump->um_dev;
 retry:
-	if ((*vpp = ufs_ihashget(dev, ino, LK_EXCLUSIVE)) != NULL) {
-		VOP_UNLOCK(*vpp);
+	if ((*vpp = ufs_ihashget(dev, ino, 0, true)) != NULL)
 		return (0);
-	}
 
 	/* Allocate a new vnode/inode. */
 	error = getnewvnode(VT_EXT2FS, mp, ext2fs_vnodeop_p, NULL, 0, &vp);
@@ -975,7 +973,7 @@ retry:
 	ip = pool_get(&ext2fs_inode_pool, PR_WAITOK);
 
 	mutex_enter(&ufs_hashlock);
-	if ((*vpp = ufs_ihashget(dev, ino, 0)) != NULL) {
+	if ((*vpp = ufs_ihashget(dev, ino, 0, false)) != NULL) {
 		mutex_exit(&ufs_hashlock);
 		ungetnewvnode(vp);
 		pool_put(&ext2fs_inode_pool, ip);
@@ -1014,11 +1012,11 @@ retry:
 		 * The inode does not contain anything useful, so it would
 		 * be misleading to leave it on its hash chain. With mode
 		 * still zero, it will be unlinked and returned to the free
-		 * list by vput().
+		 * list by vrele().
 		 */
 
 		vready_fail(vp);
-		vput(vp);
+		vrele(vp);
 		*vpp = NULL;
 		return (error);
 	}
@@ -1043,7 +1041,7 @@ retry:
 	error = ext2fs_vinit(mp, ext2fs_specop_p, ext2fs_fifoop_p, &vp);
 	if (error) {
 		vready_fail(vp);
-		vput(vp);
+		vrele(vp);
 		*vpp = NULL;
 		return (error);
 	}
@@ -1068,7 +1066,6 @@ retry:
 	}
 	uvm_vnp_setsize(vp, ext2fs_size(ip));
 	vready(vp);
-	VOP_UNLOCK(vp);
 	*vpp = vp;
 	return (0);
 }
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 9db6ab7..c0d5d21 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -1743,10 +1743,8 @@ ffs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 	dev = ump->um_dev;
 
  retry:
-	if ((*vpp = ufs_ihashget(dev, ino, LK_EXCLUSIVE)) != NULL) {
-		VOP_UNLOCK(*vpp);
+	if ((*vpp = ufs_ihashget(dev, ino, 0, true)) != NULL)
 		return (0);
-	}
 
 	/* Allocate a new vnode/inode. */
 	error = getnewvnode(VT_UFS, mp, ffs_vnodeop_p, NULL, 0, &vp);
@@ -1761,7 +1759,7 @@ ffs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 	 * vnode/inode pair and retry.
 	 */
 	mutex_enter(&ufs_hashlock);
-	if (ufs_ihashget(dev, ino, 0) != NULL) {
+	if (ufs_ihashget(dev, ino, 0, false) != NULL) {
 		mutex_exit(&ufs_hashlock);
 		ungetnewvnode(vp);
 		pool_cache_put(ffs_inode_cache, ip);
@@ -1811,11 +1809,11 @@ ffs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 		 * The inode does not contain anything useful, so it would
 		 * be misleading to leave it on its hash chain. With mode
 		 * still zero, it will be unlinked and returned to the free
-		 * list by vput().
+		 * list by vrele().
 		 */
 
 		vready_fail(vp);
-		vput(vp);
+		vrele(vp);
 		*vpp = NULL;
 		return (error);
 	}
@@ -1853,7 +1851,6 @@ ffs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 	}							/* XXX */
 	uvm_vnp_setsize(vp, ip->i_size);
 	vready(vp);
-	VOP_UNLOCK(vp);
 	*vpp = vp;
 	return (0);
 }
diff --git a/sys/ufs/ufs/ufs_extern.h b/sys/ufs/ufs/ufs_extern.h
index db91181..4413c3b 100644
--- a/sys/ufs/ufs/ufs_extern.h
+++ b/sys/ufs/ufs/ufs_extern.h
@@ -113,7 +113,7 @@ void	ufs_ihashinit(void);
 void	ufs_ihashreinit(void);
 void	ufs_ihashdone(void);
 struct vnode *ufs_ihashlookup(dev_t, ino_t);
-struct vnode *ufs_ihashget(dev_t, ino_t, int);
+struct vnode *ufs_ihashget(dev_t, ino_t, int, bool);
 void	ufs_ihashins(struct inode *);
 void	ufs_ihashrem(struct inode *);
 
diff --git a/sys/ufs/ufs/ufs_ihash.c b/sys/ufs/ufs/ufs_ihash.c
index c604555..d363f9e0 100644
--- a/sys/ufs/ufs/ufs_ihash.c
+++ b/sys/ufs/ufs/ufs_ihash.c
@@ -133,7 +133,7 @@ ufs_ihashlookup(dev_t dev, ino_t inum)
  * to it. If it is in core, but locked, wait for it.
  */
 struct vnode *
-ufs_ihashget(dev_t dev, ino_t inum, int flags)
+ufs_ihashget(dev_t dev, ino_t inum, int flags, bool do_vget)
 {
 	struct ihashhead *ipp;
 	struct inode *ip;
@@ -145,7 +145,7 @@ ufs_ihashget(dev_t dev, ino_t inum, int flags)
 	LIST_FOREACH(ip, ipp, i_hash) {
 		if (inum == ip->i_number && dev == ip->i_dev) {
 			vp = ITOV(ip);
-			if (flags == 0) {
+			if (!do_vget) {
 				mutex_exit(&ufs_ihash_lock);
 			} else {
 				mutex_enter(vp->v_interlock);
@@ -161,20 +161,15 @@ ufs_ihashget(dev_t dev, ino_t inum, int flags)
 }
 
 /*
- * Insert the inode into the hash table, and return it locked.
+ * Insert the inode into the hash table.
  */
 void
 ufs_ihashins(struct inode *ip)
 {
 	struct ihashhead *ipp;
-	int error __diagused;
 
 	KASSERT(mutex_owned(&ufs_hashlock));
 
-	/* lock the inode, then put it on the appropriate hash list */
-	error = VOP_LOCK(ITOV(ip), LK_EXCLUSIVE);
-	KASSERT(error == 0);
-
 	mutex_enter(&ufs_ihash_lock);
 	ipp = &ihashtbl[INOHASH(ip->i_dev, ip->i_number)];
 	LIST_INSERT_HEAD(ipp, ip, i_hash);
-- 
1.8.3.1