svn commit: r222886 - stable/8/sys/fs/nfsclient

[Rick Macklem]

Author: rmacklem
Date: Thu Jun  9 01:10:39 2011
New Revision: 222886
URL: http://svn.freebsd.org/changeset/base/222886

Log:
  MFC: r222329
  Add a check for MNTK_UNMOUNTF at the beginning of nfs_sync()
  in the new NFS client so that a forced dismount doesn't
  get stuck in the VFS_SYNC() call that happens before
  VFS_UNMOUNT() in dounmount().
  Additional changes are needed before forced dismounts will work.

Modified:
  stable/8/sys/fs/nfsclient/nfs_clvfsops.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)

Modified: stable/8/sys/fs/nfsclient/nfs_clvfsops.c
==============================================================================
--- stable/8/sys/fs/nfsclient/nfs_clvfsops.c	Thu Jun  9 00:34:56 2011	(r222885)
+++ stable/8/sys/fs/nfsclient/nfs_clvfsops.c	Thu Jun  9 01:10:39 2011	(r222886)
@@ -1454,10 +1454,20 @@ nfs_sync(struct mount *mp, int waitfor)
 
 	td = curthread;
 
+	MNT_ILOCK(mp);
+	/*
+	 * If a forced dismount is in progress, return from here so that
+	 * the umount(2) syscall doesn't get stuck in VFS_SYNC() before
+	 * calling VFS_UNMOUNT().
+	 */
+	if ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0) {
+		MNT_IUNLOCK(mp);
+		return (EBADF);
+	}
+
 	/*
 	 * Force stale buffer cache information to be flushed.
 	 */
-	MNT_ILOCK(mp);
 loop:
 	MNT_VNODE_FOREACH(vp, mp, mvp) {
 		VI_LOCK(vp);