tree 9b0da640a8bea9a66a093ecf1623181db30cf68e
parent f70123c6d3accc024445eca6b9ee01c1fe2b80d8
author Chris Perl <cperl@janestreet.com> 1545062198 -0500
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1549997167 +0100

NFS: nfs_compare_mount_options always compare auth flavors.

[ Upstream commit 594d1644cd59447f4fceb592448d5cd09eb09b5e ]

This patch removes the check from nfs_compare_mount_options to see if a
`sec' option was passed for the current mount before comparing auth
flavors and instead just always compares auth flavors.

Consider the following scenario:

You have a server with the address 192.168.1.1 and two exports /export/a
and /export/b.  The first export supports `sys' and `krb5' security, the
second just `sys'.

Assume you start with no mounts from the server.

The following results in EIOs being returned as the kernel nfs client
incorrectly thinks it can share the underlying `struct nfs_server's:

$ mkdir /tmp/{a,b}
$ sudo mount -t nfs -o vers=3,sec=krb5 192.168.1.1:/export/a /tmp/a
$ sudo mount -t nfs -o vers=3          192.168.1.1:/export/b /tmp/b
$ df >/dev/null
df: ‘/tmp/b’: Input/output error

Signed-off-by: Chris Perl <cperl@janestreet.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>