svn commit: r309209 - in head/sys: fs/nfsclient fs/nullfs sys

[Konstantin Belousov]

Author: kib
Date: Sun Nov 27 09:20:58 2016
New Revision: 309209
URL: https://svnweb.freebsd.org/changeset/base/309209

Log:
  NFSv4 client tracks opens, and the track records are only dropped when
  the vnode is inactivated.  This contradicts with the nullfs caching
  which keeps upper vnode around, as consequence keeping the use
  reference to lower vnode.
  
  Add a filesystem flag to request nullfs to not cache when mounted over
  that filesystem, and set the flag for nfs v4 mounts.
  
  Reported by:	asomers
  Reviewed by:	rmacklem
  Tested by:	asomers, rmacklem
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/fs/nfsclient/nfs_clvfsops.c
  head/sys/fs/nullfs/null_vfsops.c
  head/sys/sys/mount.h

Modified: head/sys/fs/nfsclient/nfs_clvfsops.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clvfsops.c	Sun Nov 27 09:14:52 2016	(r309208)
+++ head/sys/fs/nfsclient/nfs_clvfsops.c	Sun Nov 27 09:20:58 2016	(r309209)
@@ -1320,6 +1320,8 @@ out:
 		MNT_ILOCK(mp);
 		mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_NO_IOPF |
 		    MNTK_USES_BCACHE;
+		if ((VFSTONFS(mp)->nm_flag & NFSMNT_NFSV4) != 0)
+			mp->mnt_kern_flag |= MNTK_NULL_NOCACHE;
 		MNT_IUNLOCK(mp);
 	}
 	return (error);

Modified: head/sys/fs/nullfs/null_vfsops.c
==============================================================================
--- head/sys/fs/nullfs/null_vfsops.c	Sun Nov 27 09:14:52 2016	(r309208)
+++ head/sys/fs/nullfs/null_vfsops.c	Sun Nov 27 09:20:58 2016	(r309209)
@@ -188,7 +188,8 @@ nullfs_mount(struct mount *mp)
 	}
 
 	xmp->nullm_flags |= NULLM_CACHE;
-	if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0)
+	if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||
+	    (xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0)
 		xmp->nullm_flags &= ~NULLM_CACHE;
 
 	MNT_ILOCK(mp);

Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h	Sun Nov 27 09:14:52 2016	(r309208)
+++ head/sys/sys/mount.h	Sun Nov 27 09:20:58 2016	(r309209)
@@ -370,7 +370,8 @@ void          __mnt_vnode_markerfree_act
 #define	MNTK_SUSPEND	0x08000000	/* request write suspension */
 #define	MNTK_SUSPEND2	0x04000000	/* block secondary writes */
 #define	MNTK_SUSPENDED	0x10000000	/* write operations are suspended */
-#define	MNTK_UNUSED1	0x20000000
+#define	MNTK_NULL_NOCACHE	0x20000000 /* auto disable cache for nullfs
+					      mounts over this fs */
 #define MNTK_LOOKUP_SHARED	0x40000000 /* FS supports shared lock lookups */
 #define	MNTK_NOKNOTE	0x80000000	/* Don't send KNOTEs from VOP hooks */