diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst
index cbe542ad5233..960be64446cb 100644
--- a/Documentation/filesystems/nfs/exporting.rst
+++ b/Documentation/filesystems/nfs/exporting.rst
@@ -190,3 +190,15 @@ following flags are defined:
     this on filesystems that have an expensive ->getattr inode operation,
     or when atomicity between pre and post operation attribute collection
     is impossible to guarantee.
+
+  EXPORT_OP_NOSUBTREECHK - disallow subtree checking on this fs
+    Many NFS operations deal with filehandles, which the server must then
+    vet to ensure that they live inside of an exported tree. When the
+    export consists of an entire filesystem, this is trivial. nfsd can just
+    ensure that the filehandle live on the filesystem. When only part of a
+    filesystem is exported however, then nfsd must walk the ancestors of the
+    inode to ensure that it's within an exported subtree. This is an
+    expensive operation and not all filesystems can support it properly.
+    This flag exempts the filesystem from subtree checking and causes
+    exportfs to get back an error if it tries to enable subtree checking
+    on it.
diff --git a/fs/nfs/export.c b/fs/nfs/export.c
index 8f4c528865c5..b9ba306bf912 100644
--- a/fs/nfs/export.c
+++ b/fs/nfs/export.c
@@ -171,5 +171,5 @@ const struct export_operations nfs_export_ops = {
 	.encode_fh = nfs_encode_fh,
 	.fh_to_dentry = nfs_fh_to_dentry,
 	.get_parent = nfs_get_parent,
-	.flags = EXPORT_OP_NOWCC,
+	.flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK,
 };
diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 21e404e7cb68..81e7bb12aca6 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -408,6 +408,12 @@ static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
 		return -EINVAL;
 	}
 
+	if (inode->i_sb->s_export_op->flags & EXPORT_OP_NOSUBTREECHK &&
+	    !(*flags & NFSEXP_NOSUBTREECHECK)) {
+		dprintk("%s: %s does not support subtree checking!\n",
+			__func__, inode->i_sb->s_type->name);
+		return -EINVAL;
+	}
 	return 0;
 
 }
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index e7de0103a32e..2fcbab0f6b61 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -214,6 +214,7 @@ struct export_operations {
 	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
 			     int nr_iomaps, struct iattr *iattr);
 #define	EXPORT_OP_NOWCC		(0x1)	/* Don't collect wcc data for NFSv3 replies */
+#define	EXPORT_OP_NOSUBTREECHK	(0x2)	/* Subtree checking is not supported! */
 	unsigned long	flags;
 };