LU-13754 gss: open sptlrpc init channel in R+W mode

Linux 5.3 changed struct cache_detail readers to writers.
As this mechanism is used by GSS authentication in Lustre via SunRPC,
we need to make sure lsvcgssd daemon does open
/proc/net/rpc/auth.sptlrpc.init/channel in R+W mode.

It also affects CentOS/RHEL 7.8, as the kernel commit was ported to
these distros.

Lustre-commit: 0d59f1a2c1e88495d1d697acabb572f67ccc211e
Lustre-change: https://review.whamcloud.com/39297

Test-Parameters: trivial
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: If88802d4f2bc3168dda4f79fe57f2f44ac7ef39e
Reviewed-on: https://review.whamcloud.com/40367
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/utils/gss/svcgssd_main_loop.c b/lustre/utils/gss/svcgssd_main_loop.c
index 18f7985..bfd0624 100644 (file)
--- a/lustre/utils/gss/svcgssd_main_loop.c
+++ b/lustre/utils/gss/svcgssd_main_loop.c
@@ -73,7 +73,7 @@ svcgssd_run()
                int save_err;
 
                while (f == NULL) {
-                       f = fopen(gss_rpc_channel_path, "rw");
+                       f = fopen(gss_rpc_channel_path, "r+");
                        if (f == NULL) {
                                printerr(4, "failed to open %s: %s\n",
                                         gss_rpc_channel_path, strerror(errno));