[PATCH v1 1/3] nfsdctl: report NFSv4 grace state

[Prabhakar Pujeri <prabhakar.pujeri@dell.com>]

The threads command reports the server's thread configuration, but an
operator also needs to know whether the NFSv4 server is accepting normal
state operations or only recovery requests.

Display the kernel's new in-grace value when the attribute is present.
Checking its presence prevents a new nfsdctl from reporting an older
kernel's lack of the attribute as "no".

Signed-off-by: Prabhakar Pujeri <prabhakar.pujeri@dell.com>
---
 configure.ac                   | 2 +-
 support/include/nfsd_netlink.h | 1 +
 utils/nfsdctl/nfsdctl.8        | 3 ++-
 utils/nfsdctl/nfsdctl.adoc     | 3 ++-
 utils/nfsdctl/nfsdctl.c        | 8 ++++++++
 5 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 2ce1e12..96aa82c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -259,7 +259,7 @@ AC_CHECK_HEADERS(linux/nfsd_netlink.h)
 
 # ensure the system netlink headers have the latest features
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <linux/nfsd_netlink.h>]],
-			                   [[int foo = NFSD_CMD_SERVER_STATS_GET;]])],
+			                   [[int foo = NFSD_A_SERVER_IN_GRACE;]])],
 			   [AC_DEFINE([USE_SYSTEM_NFSD_NETLINK_H], 1,
 				      ["Use system's linux/nfsd_netlink.h"])])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <linux/lockd_netlink.h>]],
diff --git a/support/include/nfsd_netlink.h b/support/include/nfsd_netlink.h
index 87da1d0..e1fc2db 100644
--- a/support/include/nfsd_netlink.h
+++ b/support/include/nfsd_netlink.h
@@ -84,6 +84,7 @@ enum {
 	NFSD_A_SERVER_SCOPE,
 	NFSD_A_SERVER_MIN_THREADS,
 	NFSD_A_SERVER_FH_KEY,
+	NFSD_A_SERVER_IN_GRACE,
 
 	__NFSD_A_SERVER_MAX,
 	NFSD_A_SERVER_MAX = (__NFSD_A_SERVER_MAX - 1)
diff --git a/utils/nfsdctl/nfsdctl.8 b/utils/nfsdctl/nfsdctl.8
index 1f526e7..58d5cd9 100644
--- a/utils/nfsdctl/nfsdctl.8
+++ b/utils/nfsdctl/nfsdctl.8
@@ -144,7 +144,8 @@ takes no arguments.
 Get/set the number of running nfsd threads in each pool. Pass a list of
 integers to change the currently active number of threads. Passing it a
 value of 0 will shut down the NFS server. Run this without arguments to
-get the current number of running threads in each pool.
+get the current number of running threads in each pool and whether the
+NFSv4 server is in its recovery grace period.
 .RE
 .sp
 .if n .RS 4
diff --git a/utils/nfsdctl/nfsdctl.adoc b/utils/nfsdctl/nfsdctl.adoc
index e85348e..7e03933 100644
--- a/utils/nfsdctl/nfsdctl.adoc
+++ b/utils/nfsdctl/nfsdctl.adoc
@@ -82,7 +82,8 @@ Each subcommand can also accept its own set of options and arguments. The
   Get/set the number of running nfsd threads in each pool. Pass a list of
   integers to change the currently active number of threads. Passing it a
   value of 0 will shut down the NFS server. Run this without arguments to
-  get the current number of running threads in each pool.
+  get the current number of running threads in each pool and whether the
+  NFSv4 server is in its recovery grace period.
 
 [source,bash]
 ----
diff --git a/utils/nfsdctl/nfsdctl.c b/utils/nfsdctl/nfsdctl.c
index c712674..2b1faef 100644
--- a/utils/nfsdctl/nfsdctl.c
+++ b/utils/nfsdctl/nfsdctl.c
@@ -311,6 +311,8 @@ static void parse_threads_get(struct genlmsghdr *gnlh)
 	struct nlattr *attr;
 	int rem, pools = 0, i = 0;
 	uint32_t *pool_threads = NULL;
+	bool in_grace = false;
+	bool have_in_grace = false;
 
 	nla_for_each_attr(attr, genlmsg_attrdata(gnlh, 0),
 			  genlmsg_attrlen(gnlh, 0), rem)
@@ -337,6 +339,10 @@ static void parse_threads_get(struct genlmsghdr *gnlh)
 		case NFSD_A_SERVER_MIN_THREADS:
 			printf("min-threads: %u\n", nla_get_u32(attr));
 			break;
+		case NFSD_A_SERVER_IN_GRACE:
+			in_grace = nla_get_u8(attr);
+			have_in_grace = true;
+			break;
 		default:
 			break;
 		}
@@ -346,6 +352,8 @@ static void parse_threads_get(struct genlmsghdr *gnlh)
 	for (i = 0; i < pools; ++i)
 		printf(" %d", pool_threads[i]);
 	putchar('\n');
+	if (have_in_grace)
+		printf("in-grace: %s\n", in_grace ? "yes" : "no");
 }
 
 static void parse_pool_mode_get(struct genlmsghdr *gnlh)
-- 
2.54.0