[RFC PATCH 6/8] vfs: Convert hypfs to fs_context

[David Howells <dhowells@redhat.com>]

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
cc: Heiko Carstens <heiko.carstens@de.ibm.com>
cc: linux-s390@vger.kernel.org
---

 arch/s390/hypfs/inode.c |  128 ++++++++++++++++++++++++++---------------------
 1 file changed, 70 insertions(+), 58 deletions(-)

diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index b5cfcad953c2..d1b5f75334af 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -12,17 +12,17 @@
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/namei.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <linux/time.h>
-#include <linux/parser.h>
 #include <linux/sysfs.h>
 #include <linux/init.h>
 #include <linux/kobject.h>
 #include <linux/seq_file.h>
-#include <linux/mount.h>
 #include <linux/uio.h>
 #include <asm/ebcdic.h>
 #include "hypfs.h"
@@ -207,52 +207,44 @@ static int hypfs_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-enum { opt_uid, opt_gid, opt_err };
+enum { Opt_uid, Opt_gid, };
 
-static const match_table_t hypfs_tokens = {
-	{opt_uid, "uid=%u"},
-	{opt_gid, "gid=%u"},
-	{opt_err, NULL}
+static const struct fs_parameter_spec hypfs_param_specs[] = {
+	fsparam_u32("gid", Opt_gid),
+	fsparam_u32("uid", Opt_uid),
+	{}
 };
 
-static int hypfs_parse_options(char *options, struct super_block *sb)
+static const struct fs_parameter_description hypfs_fs_parameters = {
+	.name		= "hypfs",
+	.specs		= hypfs_param_specs,
+};
+
+static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	char *str;
-	substring_t args[MAX_OPT_ARGS];
+	struct hypfs_sb_info *hypfs_info = fc->s_fs_info;
+	struct fs_parse_result result;
 	kuid_t uid;
 	kgid_t gid;
-
-	if (!options)
-		return 0;
-	while ((str = strsep(&options, ",")) != NULL) {
-		int token, option;
-		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
-
-		if (!*str)
-			continue;
-		token = match_token(str, hypfs_tokens, args);
-		switch (token) {
-		case opt_uid:
-			if (match_int(&args[0], &option))
-				return -EINVAL;
-			uid = make_kuid(current_user_ns(), option);
-			if (!uid_valid(uid))
-				return -EINVAL;
-			hypfs_info->uid = uid;
-			break;
-		case opt_gid:
-			if (match_int(&args[0], &option))
-				return -EINVAL;
-			gid = make_kgid(current_user_ns(), option);
-			if (!gid_valid(gid))
-				return -EINVAL;
-			hypfs_info->gid = gid;
-			break;
-		case opt_err:
-		default:
-			pr_err("%s is not a valid mount option\n", str);
-			return -EINVAL;
-		}
+	int opt;
+
+	opt = fs_parse(fc, &hypfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		uid = make_kuid(current_user_ns(), result.uint_32);
+		if (!uid_valid(uid))
+			return invalf(fc, "Unknown uid");
+		hypfs_info->uid = uid;
+		break;
+	case Opt_gid:
+		gid = make_kgid(current_user_ns(), result.uint_32);
+		if (!gid_valid(gid))
+			return invalf(fc, "Unknown gid");
+		hypfs_info->gid = gid;
+		break;
 	}
 	return 0;
 }
@@ -266,26 +258,18 @@ static int hypfs_show_options(struct seq_file *s, struct dentry *root)
 	return 0;
 }
 
-static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
+static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct hypfs_sb_info *sbi = sb->s_fs_info;
 	struct inode *root_inode;
 	struct dentry *root_dentry, *update_file;
-	int rc = 0;
-	struct hypfs_sb_info *sbi;
+	int rc;
 
-	sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
-	if (!sbi)
-		return -ENOMEM;
-	mutex_init(&sbi->lock);
-	sbi->uid = current_uid();
-	sbi->gid = current_gid();
-	sb->s_fs_info = sbi;
 	sb->s_blocksize = PAGE_SIZE;
 	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = HYPFS_MAGIC;
 	sb->s_op = &hypfs_s_ops;
-	if (hypfs_parse_options(data, sb))
-		return -EINVAL;
+
 	root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
 	if (!root_inode)
 		return -ENOMEM;
@@ -309,10 +293,37 @@ static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
-			const char *devname, void *data)
+static int hypfs_get_tree(struct fs_context *fc)
+{
+	return vfs_get_super(fc, vfs_get_single_super, hypfs_fill_super);
+}
+
+static void hypfs_free_fc(struct fs_context *fc)
 {
-	return mount_single(fst, flags, data, hypfs_fill_super);
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations hypfs_context_ops = {
+	.free		= hypfs_free_fc,
+	.parse_param	= hypfs_parse_param,
+	.get_tree	= hypfs_get_tree,
+};
+
+static int hypfs_init_fs_context(struct fs_context *fc)
+{
+	struct hypfs_sb_info *sbi;
+
+	sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	mutex_init(&sbi->lock);
+	sbi->uid = current_uid();
+	sbi->gid = current_gid();
+
+	fc->s_fs_info = sbi;
+	fc->ops = &hypfs_context_ops;
+	return 0;
 }
 
 static void hypfs_kill_super(struct super_block *sb)
@@ -443,7 +454,8 @@ static const struct file_operations hypfs_file_ops = {
 static struct file_system_type hypfs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "s390_hypfs",
-	.mount		= hypfs_mount,
+	.init_fs_context = hypfs_init_fs_context,
+	.parameters	= &hypfs_fs_parameters,
 	.kill_sb	= hypfs_kill_super
 };