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Subject: [PATCH RFC 12/30] NFSD: Hook up the filecache stat file
From:   Chuck Lever <chuck.lever@oracle.com>
To:     linux-nfs@vger.kernel.org, netdev@vger.kernel.org
Cc:     david@fromorbit.com, tgraf@suug.ch, jlayton@redhat.com
Date:   Wed, 22 Jun 2022 10:14:05 -0400
Message-ID: <165590724513.75778.16837692771867171102.stgit@manet.1015granger.net>
In-Reply-To: <165590626293.75778.9843437418112335153.stgit@manet.1015granger.net>
References: <165590626293.75778.9843437418112335153.stgit@manet.1015granger.net>
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There has always been the capability of exporting filecache metrics
via /proc, but it was never hooked up. Let's surface these metrics
to enable better observability of the filecache.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfsctl.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 0621c2faf242..631bf8422c0f 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -25,6 +25,7 @@
 #include "state.h"
 #include "netns.h"
 #include "pnfs.h"
+#include "filecache.h"
 
 /*
  *	We have a single directory with several nodes in it.
@@ -46,6 +47,7 @@ enum {
 	NFSD_MaxBlkSize,
 	NFSD_MaxConnections,
 	NFSD_SupportedEnctypes,
+	NFSD_Filecache,
 	/*
 	 * The below MUST come last.  Otherwise we leave a hole in nfsd_files[]
 	 * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
@@ -229,6 +231,13 @@ static const struct file_operations reply_cache_stats_operations = {
 	.release	= single_release,
 };
 
+static const struct file_operations filecache_ops = {
+	.open		= nfsd_file_cache_stats_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 /*----------------------------------------------------------------------------*/
 /*
  * payload - write methods
@@ -1371,6 +1380,7 @@ static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
 		[NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
 		[NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},
 		[NFSD_MaxConnections] = {"max_connections", &transaction_ops, S_IWUSR|S_IRUGO},
+		[NFSD_Filecache] = {"filecache", &filecache_ops, S_IRUGO},
 #if defined(CONFIG_SUNRPC_GSS) || defined(CONFIG_SUNRPC_GSS_MODULE)
 		[NFSD_SupportedEnctypes] = {"supported_krb5_enctypes", &supported_enctypes_ops, S_IRUGO},
 #endif /* CONFIG_SUNRPC_GSS or CONFIG_SUNRPC_GSS_MODULE */