linux-kernel - [PATCH 05/14] ramfs: Implement show

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Date:   Wed, 05 Jul 2017 16:24:42 +0100
From:   David Howells <dhowells@...hat.com>
To:     viro@...iv.linux.org.uk
Cc:     dhowells@...hat.com, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 05/14] ramfs: Implement show_options

Implement the show_options superblock op for ramfs as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Signed-off-by: David Howells <dhowells@...hat.com>
---

 fs/ramfs/inode.c |   32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 26e45863e499..11201b2d06b9 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -38,6 +38,14 @@
 #include <linux/uaccess.h>
 #include "internal.h"
 
+struct ramfs_mount_opts {
+	umode_t mode;
+};
+
+struct ramfs_fs_info {
+	struct ramfs_mount_opts mount_opts;
+};
+
 #define RAMFS_DEFAULT_MODE	0755
 
 static const struct super_operations ramfs_ops;
@@ -149,14 +157,22 @@ static const struct inode_operations ramfs_dir_inode_operations = {
 	.rename		= simple_rename,
 };
 
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int ramfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct ramfs_fs_info *fsi = root->d_sb->s_fs_info;
+
+	if (fsi->mount_opts.mode != RAMFS_DEFAULT_MODE)
+		seq_printf(m, ",mode=%o", fsi->mount_opts.mode);
+	return 0;
+}
+
 static const struct super_operations ramfs_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
-	.show_options	= generic_show_options,
-};
-
-struct ramfs_mount_opts {
-	umode_t mode;
+	.show_options	= ramfs_show_options,
 };
 
 enum {
@@ -169,10 +185,6 @@ static const match_table_t tokens = {
 	{Opt_err, NULL}
 };
 
-struct ramfs_fs_info {
-	struct ramfs_mount_opts mount_opts;
-};
-
 static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts)
 {
 	substring_t args[MAX_OPT_ARGS];
@@ -211,8 +223,6 @@ int ramfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *inode;
 	int err;
 
-	save_mount_options(sb, data);
-
 	fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
 	sb->s_fs_info = fsi;
 	if (!fsi)