From: Jeff Layton <jlayton@kernel.org>
Date: Tue, 28 Apr 2020 08:10:22 -0400
Subject: ceph: fix endianness bug when handling MDS session feature bits
Git-commit: 0fa8263367db9287aa0632f96c1a5f93cc478150
Patch-mainline: v5.7-rc5
References: jsc#SES-1134
Eduard reported a problem mounting cephfs on s390 arch. The feature
mask sent by the MDS is little-endian, so we need to convert it
before storing and testing against it.
Cc: stable@vger.kernel.org
Reported-and-Tested-by: Eduard Shishkin <edward6@linux.ibm.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/mds_client.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 486f91f9685b..7c63abf5bea9 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3251,8 +3251,7 @@ static void handle_session(struct ceph_mds_session *session,
void *end = p + msg->front.iov_len;
struct ceph_mds_session_head *h;
u32 op;
- u64 seq;
- unsigned long features = 0;
+ u64 seq, features = 0;
int wake = 0;
bool blacklisted = false;
@@ -3271,9 +3270,8 @@ static void handle_session(struct ceph_mds_session *session,
goto bad;
/* version >= 3, feature bits */
ceph_decode_32_safe(&p, end, len, bad);
- ceph_decode_need(&p, end, len, bad);
- memcpy(&features, p, min_t(size_t, len, sizeof(features)));
- p += len;
+ ceph_decode_64_safe(&p, end, features, bad);
+ p += len - sizeof(features);
}
mutex_lock(&mdsc->mutex);