From: Chengguang Xu <cgxu519@icloud.com>
Date: Fri, 23 Feb 2018 17:09:38 +0800
Subject: ceph: adding protection for showing cap reservation info
Git-commit: b884014a91a49ed0e7198d276b28887cc48363bd
Patch-mainline: v4.17-rc1
References: bsc#1089115

Adding spinlock protection during getting cap reservation
ralated fields so that the numbers match below BUG_ON condition
in the code.

BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
				 mdsc->caps_reserve_count +
				 mdsc->caps_avail_count);

Signed-off-by: Chengguang Xu <cgxu519@icloud.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/caps.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -340,6 +340,8 @@ void ceph_reservation_status(struct ceph
 {
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 
+	spin_lock(&mdsc->caps_list_lock);
+
 	if (total)
 		*total = mdsc->caps_total_count;
 	if (avail)
@@ -350,6 +352,8 @@ void ceph_reservation_status(struct ceph
 		*reserved = mdsc->caps_reserve_count;
 	if (min)
 		*min = mdsc->caps_min_count;
+
+	spin_unlock(&mdsc->caps_list_lock);
 }
 
 /*