Change the new NFS server so that it returns 0 when the f_bavail

or f_ffree fields of "struct statfs" are negative, since the
values that go on the wire are unsigned and will appear to be
very large positive values otherwise. This makes the handling
of a negative f_bavail compatible with the old/regular NFS server.

MFC after:	2 weeks

1 files changed, 16 insertions, 1 deletions

diff --git a/sys/fs/nfsserver/nfs_nfsdport.c b/sys/fs/nfsserver/nfs_nfsdport.c
index 90e7d4f..9ea077d 100644
--- a/sys/fs/nfsserver/nfs_nfsdport.c
+++ b/sys/fs/nfsserver/nfs_nfsdport.c
@@ -1280,8 +1280,23 @@ nfsvno_fsync(struct vnode *vp, u_int64_t off, int cnt, struct ucred *cred,
 int
 nfsvno_statfs(struct vnode *vp, struct statfs *sf)
 {
+	int error;
 
-	return (VFS_STATFS(vp->v_mount, sf));
+	error = VFS_STATFS(vp->v_mount, sf);
+	if (error == 0) {
+		/*
+		 * Since NFS handles these values as unsigned on the
+		 * wire, there is no way to represent negative values,
+		 * so set them to 0. Without this, they will appear
+		 * to be very large positive values for clients like
+		 * Solaris10.
+		 */
+		if (sf->f_bavail < 0)
+			sf->f_bavail = 0;
+		if (sf->f_ffree < 0)
+			sf->f_ffree = 0;
+	}
+	return (error);
 }
 
 /*