svn commit: r299413 - head/sys/fs/nfsclient

[Konstantin Belousov]

Author: kib
Date: Wed May 11 06:35:46 2016
New Revision: 299413
URL: https://svnweb.freebsd.org/changeset/base/299413

Log:
  Use vfs_hash_ref(9) to eliminate LK_EXCLOTHER kludge.  As a
  consequence, the nfs client override of VOP_LOCK1() is no longer
  needed.
  
  Reviewed and tested by:	rmacklem
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/fs/nfsclient/nfs_clport.c
  head/sys/fs/nfsclient/nfs_clvnops.c

Modified: head/sys/fs/nfsclient/nfs_clport.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clport.c	Wed May 11 06:32:22 2016	(r299412)
+++ head/sys/fs/nfsclient/nfs_clport.c	Wed May 11 06:35:46 2016	(r299413)
@@ -293,7 +293,7 @@ nfscl_nget(struct mount *mntp, struct vn
 }
 
 /*
- * Anothe variant of nfs_nget(). This one is only used by reopen. It
+ * Another variant of nfs_nget(). This one is only used by reopen. It
  * takes almost the same args as nfs_nget(), but only succeeds if an entry
  * exists in the cache. (Since files should already be "open" with a
  * vnode ref cnt on the node when reopen calls this, it should always
@@ -332,21 +332,24 @@ nfscl_ngetreopen(struct mount *mntp, u_i
 		NFSVOPUNLOCK(nvp, 0);
 	} else if (error == EBUSY) {
 		/*
-		 * The LK_EXCLOTHER lock type tells nfs_lock1() to not try
-		 * and lock the vnode, but just get a v_usecount on it.
-		 * LK_NOWAIT is set so that when vget() returns ENOENT,
-		 * vfs_hash_get() fails instead of looping.
-		 * If this succeeds, it is safe so long as a vflush() with
+		 * It is safe so long as a vflush() with
 		 * FORCECLOSE has not been done. Since the Renew thread is
 		 * stopped and the MNTK_UNMOUNTF flag is set before doing
 		 * a vflush() with FORCECLOSE, we should be ok here.
 		 */
 		if ((mntp->mnt_kern_flag & MNTK_UNMOUNTF))
 			error = EINTR;
-		else
-			error = vfs_hash_get(mntp, hash,
-			    (LK_EXCLOTHER | LK_NOWAIT), td, &nvp,
-			    newnfs_vncmpf, nfhp);
+		else {
+			vfs_hash_ref(mntp, hash, td, &nvp, newnfs_vncmpf, nfhp);
+			if (nvp == NULL) {
+				error = ENOENT;
+			} else if ((nvp->v_iflag & VI_DOOMED) != 0) {
+				error = ENOENT;
+				vrele(nvp);
+			} else {
+				error = 0;
+			}
+		}
 	}
 	FREE(nfhp, M_NFSFH);
 	if (error)

Modified: head/sys/fs/nfsclient/nfs_clvnops.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clvnops.c	Wed May 11 06:32:22 2016	(r299412)
+++ head/sys/fs/nfsclient/nfs_clvnops.c	Wed May 11 06:35:46 2016	(r299413)
@@ -138,7 +138,6 @@ static vop_rmdir_t	nfs_rmdir;
 static vop_symlink_t	nfs_symlink;
 static vop_readdir_t	nfs_readdir;
 static vop_strategy_t	nfs_strategy;
-static vop_lock1_t	nfs_lock1;
 static	int	nfs_lookitup(struct vnode *, char *, int,
 		    struct ucred *, struct thread *, struct nfsnode **);
 static	int	nfs_sillyrename(struct vnode *, struct vnode *,
@@ -167,7 +166,6 @@ struct vop_vector newnfs_vnodeops = {
 	.vop_putpages =		ncl_putpages,
 	.vop_inactive =		ncl_inactive,
 	.vop_link =		nfs_link,
-	.vop_lock1 = 		nfs_lock1,
 	.vop_lookup =		nfs_lookup,
 	.vop_mkdir =		nfs_mkdir,
 	.vop_mknod =		nfs_mknod,
@@ -3349,37 +3347,6 @@ struct buf_ops buf_ops_newnfs = {
 	.bop_bdflush	=	bufbdflush,
 };
 
-/*
- * Cloned from vop_stdlock(), and then the ugly hack added.
- */
-static int
-nfs_lock1(struct vop_lock1_args *ap)
-{
-	struct vnode *vp = ap->a_vp;
-	int error = 0;
-
-	/*
-	 * Since vfs_hash_get() calls vget() and it will no longer work
-	 * for FreeBSD8 with flags == 0, I can only think of this horrible
-	 * hack to work around it. I call vfs_hash_get() with LK_EXCLOTHER
-	 * and then handle it here. All I want for this case is a v_usecount
-	 * on the vnode to use for recovery, while another thread might
-	 * hold a lock on the vnode. I have the other threads blocked, so
-	 * there isn't any race problem.
-	 */
-	if ((ap->a_flags & LK_TYPE_MASK) == LK_EXCLOTHER) {
-		if ((ap->a_flags & LK_INTERLOCK) == 0)
-			panic("ncllock1");
-		if ((vp->v_iflag & VI_DOOMED))
-			error = ENOENT;
-		VI_UNLOCK(vp);
-		return (error);
-	}
-	return (_lockmgr_args(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
-	    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, ap->a_file,
-	    ap->a_line));
-}
-
 static int
 nfs_getacl(struct vop_getacl_args *ap)
 {