From: Chengguang Xu <cgxu519@gmx.com>
Date: Thu, 19 Jul 2018 22:15:24 +0800
Subject: ceph: add new field max_file_size in ceph_fs_client
Git-commit: 719784ba706cdbb47ef87483950f0a4594d36e87
Patch-mainline: v4.19-rc1
References: FATE#324714

In order to not bother to VFS and other specific filesystems,
we decided to do offset validation inside ceph kernel client,
so just simply set sb->s_maxbytes to MAX_LFS_FILESIZE so that
it can successfully pass VFS check. We add new field max_file_size
in ceph_fs_client to store real file size limit and doing proper
check based on it.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
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 |    3 ++-
 fs/ceph/super.c      |    3 ++-
 fs/ceph/super.h      |    1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4014,7 +4014,8 @@ void ceph_mdsc_handle_mdsmap(struct ceph
 	} else {
 		mdsc->mdsmap = newmap;  /* first mds map */
 	}
-	mdsc->fsc->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
+	mdsc->fsc->max_file_size = min((loff_t)mdsc->mdsmap->m_max_file_size,
+					MAX_LFS_FILESIZE);
 
 	__wake_requests(mdsc, &mdsc->waiting_for_map);
 	ceph_monc_got_map(&mdsc->fsc->client->monc, CEPH_SUB_MDSMAP,
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -940,11 +940,12 @@ static int ceph_set_super(struct super_b
 	dout("set_super %p data %p\n", s, data);
 
 	s->s_flags = fsc->mount_options->sb_flags;
-	s->s_maxbytes = 1ULL << 40;  /* temp value until we get mdsmap */
+	s->s_maxbytes = MAX_LFS_FILESIZE;
 
 	s->s_xattr = ceph_xattr_handlers;
 	s->s_fs_info = fsc;
 	fsc->sb = s;
+	fsc->max_file_size = 1ULL << 40; /* temp value until we get mdsmap */
 
 	s->s_op = &ceph_super_ops;
 	s->s_d_op = &ceph_dentry_ops;
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -97,6 +97,7 @@ struct ceph_fs_client {
 
 	unsigned long mount_state;
 	int min_caps;                  /* min caps i added */
+	loff_t max_file_size;
 
 	struct ceph_mds_client *mdsc;