vfs: Convert jffs2 to use the new mount API

Convert the jffs2 filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: David Woodhouse <dwmw2@infradead.org>
cc: linux-mtd@lists.infradead.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 83 insertions, 89 deletions

diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index af4aa6599473..cbe70637c117 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -19,7 +19,8 @@
 #include <linux/fs.h>
 #include <linux/err.h>
 #include <linux/mount.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/jffs2.h>
 #include <linux/pagemap.h>
 #include <linux/mtd/super.h>
@@ -157,96 +158,77 @@ static const struct export_operations jffs2_export_ops = {
 /*
  * JFFS2 mount options.
  *
+ * Opt_source: The source device
  * Opt_override_compr: override default compressor
  * Opt_rp_size: size of reserved pool in KiB
- * Opt_err: just end of array marker
  */
 enum {
+	Opt_source,
 	Opt_override_compr,
 	Opt_rp_size,
-	Opt_err,
 };
 
-static const match_table_t tokens = {
-	{Opt_override_compr, "compr=%s"},
-	{Opt_rp_size, "rp_size=%u"},
-	{Opt_err, NULL},
+static const struct fs_parameter_spec jffs2_param_specs[] = {
+	fsparam_string	("source",	Opt_source),
+	fsparam_enum	("compr",	Opt_override_compr),
+	fsparam_u32	("rp_size",	Opt_rp_size),
+	{}
 };
 
-static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
-{
-	substring_t args[MAX_OPT_ARGS];
-	char *p, *name;
-	unsigned int opt;
-
-	if (!data)
-		return 0;
-
-	while ((p = strsep(&data, ","))) {
-		int token;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_override_compr:
-			name = match_strdup(&args[0]);
-
-			if (!name)
-				return -ENOMEM;
-			if (!strcmp(name, "none"))
-				c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
+static const struct fs_parameter_enum jffs2_param_enums[] = {
+	{ Opt_override_compr,	"none",	JFFS2_COMPR_MODE_NONE },
 #ifdef CONFIG_JFFS2_LZO
-			else if (!strcmp(name, "lzo"))
-				c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
+	{ Opt_override_compr,	"lzo",	JFFS2_COMPR_MODE_FORCELZO },
 #endif
 #ifdef CONFIG_JFFS2_ZLIB
-			else if (!strcmp(name, "zlib"))
-				c->mount_opts.compr =
-						JFFS2_COMPR_MODE_FORCEZLIB;
+	{ Opt_override_compr,	"zlib",	JFFS2_COMPR_MODE_FORCEZLIB },
 #endif
-			else {
-				pr_err("Error: unknown compressor \"%s\"\n",
-				       name);
-				kfree(name);
-				return -EINVAL;
-			}
-			kfree(name);
-			c->mount_opts.override_compr = true;
-			break;
-		case Opt_rp_size:
-			if (match_int(&args[0], &opt))
-				return -EINVAL;
-			opt *= 1024;
-			if (opt > c->mtd->size) {
-				pr_warn("Too large reserve pool specified, max "
-					"is %llu KB\n", c->mtd->size / 1024);
-				return -EINVAL;
-			}
-			c->mount_opts.rp_size = opt;
-			break;
-		default:
-			pr_err("Error: unrecognized mount option '%s' or missing value\n",
-			       p);
-			return -EINVAL;
-		}
+	{}
+};
+
+const struct fs_parameter_description jffs2_fs_parameters = {
+	.name		= "jffs2",
+	.specs		= jffs2_param_specs,
+	.enums		= jffs2_param_enums,
+};
+
+static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct fs_parse_result result;
+	struct jffs2_sb_info *c = fc->s_fs_info;
+	int opt;
+
+	opt = fs_parse(fc, &jffs2_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_override_compr:
+		c->mount_opts.compr = result.uint_32;
+		c->mount_opts.override_compr = true;
+		break;
+	case Opt_rp_size:
+		if (result.uint_32 > UINT_MAX / 1024)
+			return invalf(fc, "jffs2: rp_size unrepresentable");
+		opt = result.uint_32 * 1024;
+		if (opt > c->mtd->size)
+			return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
+				      c->mtd->size / 1024);
+		c->mount_opts.rp_size = opt;
+		break;
+	default:
+		return -EINVAL;
 	}
 
 	return 0;
 }
 
-static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
+static int jffs2_reconfigure(struct fs_context *fc)
 {
-	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
-	int err;
+	struct super_block *sb = fc->root->d_sb;
 
 	sync_filesystem(sb);
-	err = jffs2_parse_options(c, data);
-	if (err)
-		return -EINVAL;
-
-	return jffs2_do_remount_fs(sb, flags, data);
+	return jffs2_do_remount_fs(sb, fc);
 }
 
 static const struct super_operations jffs2_super_operations =
@@ -255,7 +237,6 @@ static const struct super_operations jffs2_super_operations =
 	.free_inode =	jffs2_free_inode,
 	.put_super =	jffs2_put_super,
 	.statfs =	jffs2_statfs,
-	.remount_fs =	jffs2_remount_fs,
 	.evict_inode =	jffs2_evict_inode,
 	.dirty_inode =	jffs2_dirty_inode,
 	.show_options =	jffs2_show_options,
@@ -265,26 +246,16 @@ static const struct super_operations jffs2_super_operations =
 /*
  * fill in the superblock
  */
-static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
+static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
 {
-	struct jffs2_sb_info *c;
-	int ret;
+	struct jffs2_sb_info *c = sb->s_fs_info;
 
 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
 		  " New superblock for device %d (\"%s\")\n",
 		  sb->s_mtd->index, sb->s_mtd->name);
 
-	c = kzalloc(sizeof(*c), GFP_KERNEL);
-	if (!c)
-		return -ENOMEM;
-
 	c->mtd = sb->s_mtd;
 	c->os_priv = sb;
-	sb->s_fs_info = c;
-
-	ret = jffs2_parse_options(c, data);
-	if (ret)
-		return -EINVAL;
 
 	/* Initialize JFFS2 superblock locks, the further initialization will
 	 * be done later */
@@ -302,15 +273,37 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 	sb->s_flags |= SB_POSIXACL;
 #endif
-	ret = jffs2_do_fill_super(sb, data, silent);
-	return ret;
+	return jffs2_do_fill_super(sb, fc);
 }
 
-static struct dentry *jffs2_mount(struct file_system_type *fs_type,
-			int flags, const char *dev_name,
-			void *data)
+static int jffs2_get_tree(struct fs_context *fc)
 {
-	return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
+	return get_tree_mtd(fc, jffs2_fill_super);
+}
+
+static void jffs2_free_fc(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations jffs2_context_ops = {
+	.free		= jffs2_free_fc,
+	.parse_param	= jffs2_parse_param,
+	.get_tree	= jffs2_get_tree,
+	.reconfigure	= jffs2_reconfigure,
+};
+
+static int jffs2_init_fs_context(struct fs_context *fc)
+{
+	struct jffs2_sb_info *ctx;
+
+	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	fc->s_fs_info = ctx;
+	fc->ops = &jffs2_context_ops;
+	return 0;
 }
 
 static void jffs2_put_super (struct super_block *sb)
@@ -347,7 +340,8 @@ static void jffs2_kill_sb(struct super_block *sb)
 static struct file_system_type jffs2_fs_type = {
 	.owner =	THIS_MODULE,
 	.name =		"jffs2",
-	.mount =	jffs2_mount,
+	.init_fs_context = jffs2_init_fs_context,
+	.parameters =	&jffs2_fs_parameters,
 	.kill_sb =	jffs2_kill_sb,
 };
 MODULE_ALIAS_FS("jffs2");