qnx6: convert qnx6 to use the new mount api

Convert the qnx6 filesystem to use the new mount API.

Mostly untested, since there is no qnx6 fs image readily available.
Testing did include parsing of the mmi_fs option.

Signed-off-by: Bill O'Donnell <bodonnel@redhat.com>
Link: https://lore.kernel.org/r/20240302165714.859504-1-bodonnel@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/qnx6/inode.c

@@ -19,19 +19,19 @@
 #include <linux/buffer_head.h>
 #include <linux/writeback.h>
 #include <linux/statfs.h>
-#include <linux/parser.h>
 #include <linux/seq_file.h>
-#include <linux/mount.h>
 #include <linux/crc32.h>
 #include <linux/mpage.h>
+#include <linux/fs_parser.h>
+#include <linux/fs_context.h>
 #include "qnx6.h"
 
 static const struct super_operations qnx6_sops;
 
 static void qnx6_put_super(struct super_block *sb);
 static struct inode *qnx6_alloc_inode(struct super_block *sb);
 static void qnx6_free_inode(struct inode *inode);
-static int qnx6_remount(struct super_block *sb, int *flags, char *data);
+static int qnx6_reconfigure(struct fs_context *fc);
 static int qnx6_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int qnx6_show_options(struct seq_file *seq, struct dentry *root);
 
@@ -40,7 +40,6 @@ static const struct super_operations qnx6_sops = {
 	.free_inode	= qnx6_free_inode,
 	.put_super	= qnx6_put_super,
 	.statfs		= qnx6_statfs,
-	.remount_fs	= qnx6_remount,
 	.show_options	= qnx6_show_options,
 };
 
@@ -54,10 +53,12 @@ static int qnx6_show_options(struct seq_file *seq, struct dentry *root)
 	return 0;
 }
 
-static int qnx6_remount(struct super_block *sb, int *flags, char *data)
+static int qnx6_reconfigure(struct fs_context *fc)
 {
+	struct super_block *sb = fc->root->d_sb;
+
 	sync_filesystem(sb);
-	*flags |= SB_RDONLY;
+	fc->sb_flags |= SB_RDONLY;
 	return 0;
 }
 
@@ -218,39 +219,36 @@ void qnx6_superblock_debug(struct qnx6_super_block *sb, struct super_block *s)
 #endif
 
 enum {
-	Opt_mmifs,
-	Opt_err
+	Opt_mmifs
+};
+
+struct qnx6_context {
+	unsigned long s_mount_opts;
 };
 
-static const match_table_t tokens = {
-	{Opt_mmifs, "mmi_fs"},
-	{Opt_err, NULL}
+static const struct fs_parameter_spec qnx6_param_spec[] = {
+	fsparam_flag	("mmi_fs",	Opt_mmifs),
+	{}
 };
 
-static int qnx6_parse_options(char *options, struct super_block *sb)
+static int qnx6_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	char *p;
-	struct qnx6_sb_info *sbi = QNX6_SB(sb);
-	substring_t args[MAX_OPT_ARGS];
-
-	if (!options)
-		return 1;
-
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_mmifs:
-			set_opt(sbi->s_mount_opt, MMI_FS);
-			break;
-		default:
-			return 0;
-		}
+	struct qnx6_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, qnx6_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_mmifs:
+		ctx->s_mount_opts |= QNX6_MOUNT_MMI_FS;
+		break;
+	default:
+		return -EINVAL;
 	}
-	return 1;
+	return 0;
 }
 
 static struct buffer_head *qnx6_check_first_superblock(struct super_block *s,
@@ -293,35 +291,33 @@ static struct buffer_head *qnx6_check_first_superblock(struct super_block *s,
 static struct inode *qnx6_private_inode(struct super_block *s,
 					struct qnx6_root_node *p);
 
-static int qnx6_fill_super(struct super_block *s, void *data, int silent)
+static int qnx6_fill_super(struct super_block *s, struct fs_context *fc)
 {
 	struct buffer_head *bh1 = NULL, *bh2 = NULL;
 	struct qnx6_super_block *sb1 = NULL, *sb2 = NULL;
 	struct qnx6_sb_info *sbi;
+	struct qnx6_context *ctx = fc->fs_private;
 	struct inode *root;
 	const char *errmsg;
 	struct qnx6_sb_info *qs;
 	int ret = -EINVAL;
 	u64 offset;
 	int bootblock_offset = QNX6_BOOTBLOCK_SIZE;
+	int silent = fc->sb_flags & SB_SILENT;
 
 	qs = kzalloc(sizeof(struct qnx6_sb_info), GFP_KERNEL);
 	if (!qs)
 		return -ENOMEM;
 	s->s_fs_info = qs;
+	qs->s_mount_opt = ctx->s_mount_opts;
 
 	/* Superblock always is 512 Byte long */
 	if (!sb_set_blocksize(s, QNX6_SUPERBLOCK_SIZE)) {
 		pr_err("unable to set blocksize\n");
 		goto outnobh;
 	}
 
-	/* parse the mount-options */
-	if (!qnx6_parse_options((char *) data, s)) {
-		pr_err("invalid mount options.\n");
-		goto outnobh;
-	}
-	if (test_opt(s, MMI_FS)) {
+	if (qs->s_mount_opt == QNX6_MOUNT_MMI_FS) {
 		sb1 = qnx6_mmi_fill_super(s, silent);
 		if (sb1)
 			goto mmi_success;
@@ -632,18 +628,43 @@ static void destroy_inodecache(void)
 	kmem_cache_destroy(qnx6_inode_cachep);
 }
 
-static struct dentry *qnx6_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int qnx6_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, qnx6_fill_super);
+}
+
+static void qnx6_free_fc(struct fs_context *fc)
 {
-	return mount_bdev(fs_type, flags, dev_name, data, qnx6_fill_super);
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations qnx6_context_ops = {
+	.parse_param	= qnx6_parse_param,
+	.get_tree	= qnx6_get_tree,
+	.reconfigure	= qnx6_reconfigure,
+	.free		= qnx6_free_fc,
+};
+
+static int qnx6_init_fs_context(struct fs_context *fc)
+{
+	struct qnx6_context *ctx;
+
+	ctx = kzalloc(sizeof(struct qnx6_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	fc->ops = &qnx6_context_ops;
+	fc->fs_private = ctx;
+
+	return 0;
 }
 
 static struct file_system_type qnx6_fs_type = {
-	.owner		= THIS_MODULE,
-	.name		= "qnx6",
-	.mount		= qnx6_mount,
-	.kill_sb	= kill_block_super,
-	.fs_flags	= FS_REQUIRES_DEV,
+	.owner			= THIS_MODULE,
+	.name			= "qnx6",
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+	.init_fs_context	= qnx6_init_fs_context,
+	.parameters		= qnx6_param_spec,
 };
 MODULE_ALIAS_FS("qnx6");