hfsplus: convert hfsplus to use the new mount api

Convert the hfsplus filesystem to use the new mount API.
Tested by comparing random mount & remount options before and after
the change.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/20240916172735.866916-6-sandeen@redhat.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

3 files changed, 149 insertions, 202 deletions

diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 59ce81dca73f..b733ef0c1547 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -21,6 +21,7 @@
 #include <linux/mutex.h>
 #include <linux/buffer_head.h>
 #include <linux/blkdev.h>
+#include <linux/fs_context.h>
 #include "hfsplus_raw.h"
 
 #define DBG_BNODE_REFS	0x00000001
@@ -496,8 +497,7 @@ long hfsplus_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
 
 /* options.c */
 void hfsplus_fill_defaults(struct hfsplus_sb_info *opts);
-int hfsplus_parse_options_remount(char *input, int *force);
-int hfsplus_parse_options(char *input, struct hfsplus_sb_info *sbi);
+int hfsplus_parse_param(struct fs_context *fc, struct fs_parameter *param);
 int hfsplus_show_options(struct seq_file *seq, struct dentry *root);
 
 /* part_tbl.c */
diff --git a/fs/hfsplus/options.c b/fs/hfsplus/options.c
index c94a58762ad6..a66a09a56bf7 100644
--- a/fs/hfsplus/options.c
+++ b/fs/hfsplus/options.c
@@ -12,7 +12,8 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/nls.h>
 #include <linux/mount.h>
 #include <linux/seq_file.h>
@@ -23,26 +24,23 @@ enum {
 	opt_creator, opt_type,
 	opt_umask, opt_uid, opt_gid,
 	opt_part, opt_session, opt_nls,
-	opt_nodecompose, opt_decompose,
-	opt_barrier, opt_nobarrier,
-	opt_force, opt_err
+	opt_decompose, opt_barrier,
+	opt_force,
 };
 
-static const match_table_t tokens = {
-	{ opt_creator, "creator=%s" },
-	{ opt_type, "type=%s" },
-	{ opt_umask, "umask=%o" },
-	{ opt_uid, "uid=%u" },
-	{ opt_gid, "gid=%u" },
-	{ opt_part, "part=%u" },
-	{ opt_session, "session=%u" },
-	{ opt_nls, "nls=%s" },
-	{ opt_decompose, "decompose" },
-	{ opt_nodecompose, "nodecompose" },
-	{ opt_barrier, "barrier" },
-	{ opt_nobarrier, "nobarrier" },
-	{ opt_force, "force" },
-	{ opt_err, NULL }
+static const struct fs_parameter_spec hfs_param_spec[] = {
+	fsparam_string	("creator",	opt_creator),
+	fsparam_string	("type",	opt_type),
+	fsparam_u32oct	("umask",	opt_umask),
+	fsparam_u32	("uid",		opt_uid),
+	fsparam_u32	("gid",		opt_gid),
+	fsparam_u32	("part",	opt_part),
+	fsparam_u32	("session",	opt_session),
+	fsparam_string	("nls",		opt_nls),
+	fsparam_flag_no	("decompose",	opt_decompose),
+	fsparam_flag_no	("barrier",	opt_barrier),
+	fsparam_flag	("force",	opt_force),
+	{}
 };
 
 /* Initialize an options object to reasonable defaults */
@@ -60,162 +58,89 @@ void hfsplus_fill_defaults(struct hfsplus_sb_info *opts)
 	opts->session = -1;
 }
 
-/* convert a "four byte character" to a 32 bit int with error checks */
-static inline int match_fourchar(substring_t *arg, u32 *result)
+/* Parse options from mount. Returns nonzero errno on failure */
+int hfsplus_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	if (arg->to - arg->from != 4)
-		return -EINVAL;
-	memcpy(result, arg->from, 4);
-	return 0;
-}
-
-int hfsplus_parse_options_remount(char *input, int *force)
-{
-	char *p;
-	substring_t args[MAX_OPT_ARGS];
-	int token;
-
-	if (!input)
-		return 1;
-
-	while ((p = strsep(&input, ",")) != NULL) {
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case opt_force:
-			*force = 1;
-			break;
-		default:
-			break;
+	struct hfsplus_sb_info *sbi = fc->s_fs_info;
+	struct fs_parse_result result;
+	int opt;
+
+	/*
+	 * Only the force option is examined during remount, all others
+	 * are ignored.
+	 */
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE &&
+	    strncmp(param->key, "force", 5))
+		return 0;
+
+	opt = fs_parse(fc, hfs_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case opt_creator:
+		if (strlen(param->string) != 4) {
+			pr_err("creator requires a 4 character value\n");
+			return -EINVAL;
 		}
-	}
-
-	return 1;
-}
-
-/* Parse options from mount. Returns 0 on failure */
-/* input is the options passed to mount() as a string */
-int hfsplus_parse_options(char *input, struct hfsplus_sb_info *sbi)
-{
-	char *p;
-	substring_t args[MAX_OPT_ARGS];
-	int tmp, token;
-
-	if (!input)
-		goto done;
-
-	while ((p = strsep(&input, ",")) != NULL) {
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case opt_creator:
-			if (match_fourchar(&args[0], &sbi->creator)) {
-				pr_err("creator requires a 4 character value\n");
-				return 0;
-			}
-			break;
-		case opt_type:
-			if (match_fourchar(&args[0], &sbi->type)) {
-				pr_err("type requires a 4 character value\n");
-				return 0;
-			}
-			break;
-		case opt_umask:
-			if (match_octal(&args[0], &tmp)) {
-				pr_err("umask requires a value\n");
-				return 0;
-			}
-			sbi->umask = (umode_t)tmp;
-			break;
-		case opt_uid:
-			if (match_int(&args[0], &tmp)) {
-				pr_err("uid requires an argument\n");
-				return 0;
-			}
-			sbi->uid = make_kuid(current_user_ns(), (uid_t)tmp);
-			if (!uid_valid(sbi->uid)) {
-				pr_err("invalid uid specified\n");
-				return 0;
-			} else {
-				set_bit(HFSPLUS_SB_UID, &sbi->flags);
-			}
-			break;
-		case opt_gid:
-			if (match_int(&args[0], &tmp)) {
-				pr_err("gid requires an argument\n");
-				return 0;
-			}
-			sbi->gid = make_kgid(current_user_ns(), (gid_t)tmp);
-			if (!gid_valid(sbi->gid)) {
-				pr_err("invalid gid specified\n");
-				return 0;
-			} else {
-				set_bit(HFSPLUS_SB_GID, &sbi->flags);
-			}
-			break;
-		case opt_part:
-			if (match_int(&args[0], &sbi->part)) {
-				pr_err("part requires an argument\n");
-				return 0;
-			}
-			break;
-		case opt_session:
-			if (match_int(&args[0], &sbi->session)) {
-				pr_err("session requires an argument\n");
-				return 0;
-			}
-			break;
-		case opt_nls:
-			if (sbi->nls) {
-				pr_err("unable to change nls mapping\n");
-				return 0;
-			}
-			p = match_strdup(&args[0]);
-			if (p)
-				sbi->nls = load_nls(p);
-			if (!sbi->nls) {
-				pr_err("unable to load nls mapping \"%s\"\n",
-				       p);
-				kfree(p);
-				return 0;
-			}
-			kfree(p);
-			break;
-		case opt_decompose:
-			clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
-			break;
-		case opt_nodecompose:
+		memcpy(&sbi->creator, param->string, 4);
+		break;
+	case opt_type:
+		if (strlen(param->string) != 4) {
+			pr_err("type requires a 4 character value\n");
+			return -EINVAL;
+		}
+		memcpy(&sbi->type, param->string, 4);
+		break;
+	case opt_umask:
+		sbi->umask = (umode_t)result.uint_32;
+		break;
+	case opt_uid:
+		sbi->uid = result.uid;
+		set_bit(HFSPLUS_SB_UID, &sbi->flags);
+		break;
+	case opt_gid:
+		sbi->gid = result.gid;
+		set_bit(HFSPLUS_SB_GID, &sbi->flags);
+		break;
+	case opt_part:
+		sbi->part = result.uint_32;
+		break;
+	case opt_session:
+		sbi->session = result.uint_32;
+		break;
+	case opt_nls:
+		if (sbi->nls) {
+			pr_err("unable to change nls mapping\n");
+			return -EINVAL;
+		}
+		sbi->nls = load_nls(param->string);
+		if (!sbi->nls) {
+			pr_err("unable to load nls mapping \"%s\"\n",
+			       param->string);
+			return -EINVAL;
+		}
+		break;
+	case opt_decompose:
+		if (result.negated)
 			set_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
-			break;
-		case opt_barrier:
-			clear_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
-			break;
-		case opt_nobarrier:
+		else
+			clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
+		break;
+	case opt_barrier:
+		if (result.negated)
 			set_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
-			break;
-		case opt_force:
-			set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
-			break;
-		default:
-			return 0;
-		}
-	}
-
-done:
-	if (!sbi->nls) {
-		/* try utf8 first, as this is the old default behaviour */
-		sbi->nls = load_nls("utf8");
-		if (!sbi->nls)
-			sbi->nls = load_nls_default();
-		if (!sbi->nls)
-			return 0;
+		else
+			clear_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
+		break;
+	case opt_force:
+		set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
+		break;
+	default:
+		return -EINVAL;
 	}
 
-	return 1;
+	return 0;
 }
 
 int hfsplus_show_options(struct seq_file *seq, struct dentry *root)
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 97920202790f..948b8aaee33e 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -14,6 +14,7 @@
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/slab.h>
 #include <linux/vfs.h>
 #include <linux/nls.h>
@@ -332,34 +333,33 @@ static int hfsplus_statfs(struct dentry *dentry, struct kstatfs *buf)
 	return 0;
 }
 
-static int hfsplus_remount(struct super_block *sb, int *flags, char *data)
+static int hfsplus_reconfigure(struct fs_context *fc)
 {
+	struct super_block *sb = fc->root->d_sb;
+
 	sync_filesystem(sb);
-	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
+	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
 		return 0;
-	if (!(*flags & SB_RDONLY)) {
-		struct hfsplus_vh *vhdr = HFSPLUS_SB(sb)->s_vhdr;
-		int force = 0;
-
-		if (!hfsplus_parse_options_remount(data, &force))
-			return -EINVAL;
+	if (!(fc->sb_flags & SB_RDONLY)) {
+		struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+		struct hfsplus_vh *vhdr = sbi->s_vhdr;
 
 		if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
 			pr_warn("filesystem was not cleanly unmounted, running fsck.hfsplus is recommended.  leaving read-only.\n");
 			sb->s_flags |= SB_RDONLY;
-			*flags |= SB_RDONLY;
-		} else if (force) {
+			fc->sb_flags |= SB_RDONLY;
+		} else if (test_bit(HFSPLUS_SB_FORCE, &sbi->flags)) {
 			/* nothing */
 		} else if (vhdr->attributes &
 				cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
 			pr_warn("filesystem is marked locked, leaving read-only.\n");
 			sb->s_flags |= SB_RDONLY;
-			*flags |= SB_RDONLY;
+			fc->sb_flags |= SB_RDONLY;
 		} else if (vhdr->attributes &
 				cpu_to_be32(HFSPLUS_VOL_JOURNALED)) {
 			pr_warn("filesystem is marked journaled, leaving read-only.\n");
 			sb->s_flags |= SB_RDONLY;
-			*flags |= SB_RDONLY;
+			fc->sb_flags |= SB_RDONLY;
 		}
 	}
 	return 0;
@@ -373,38 +373,33 @@ static const struct super_operations hfsplus_sops = {
 	.put_super	= hfsplus_put_super,
 	.sync_fs	= hfsplus_sync_fs,
 	.statfs		= hfsplus_statfs,
-	.remount_fs	= hfsplus_remount,
 	.show_options	= hfsplus_show_options,
 };
 
-static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
+static int hfsplus_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct hfsplus_vh *vhdr;
-	struct hfsplus_sb_info *sbi;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 	hfsplus_cat_entry entry;
 	struct hfs_find_data fd;
 	struct inode *root, *inode;
 	struct qstr str;
-	struct nls_table *nls = NULL;
+	struct nls_table *nls;
 	u64 last_fs_block, last_fs_page;
+	int silent = fc->sb_flags & SB_SILENT;
 	int err;
 
-	err = -ENOMEM;
-	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
-		goto out;
-
-	sb->s_fs_info = sbi;
 	mutex_init(&sbi->alloc_mutex);
 	mutex_init(&sbi->vh_mutex);
 	spin_lock_init(&sbi->work_lock);
 	INIT_DELAYED_WORK(&sbi->sync_work, delayed_sync_fs);
-	hfsplus_fill_defaults(sbi);
 
 	err = -EINVAL;
-	if (!hfsplus_parse_options(data, sbi)) {
-		pr_err("unable to parse mount options\n");
-		goto out_unload_nls;
+	if (!sbi->nls) {
+		/* try utf8 first, as this is the old default behaviour */
+		sbi->nls = load_nls("utf8");
+		if (!sbi->nls)
+			sbi->nls = load_nls_default();
 	}
 
 	/* temporarily use utf8 to correctly find the hidden dir below */
@@ -616,7 +611,6 @@ out_unload_nls:
 	unload_nls(sbi->nls);
 	unload_nls(nls);
 	kfree(sbi);
-out:
 	return err;
 }
 
@@ -641,18 +635,46 @@ static void hfsplus_free_inode(struct inode *inode)
 
 #define HFSPLUS_INODE_SIZE	sizeof(struct hfsplus_inode_info)
 
-static struct dentry *hfsplus_mount(struct file_system_type *fs_type,
-			  int flags, const char *dev_name, void *data)
+static int hfsplus_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, hfsplus_fill_super);
+}
+
+static void hfsplus_free_fc(struct fs_context *fc)
 {
-	return mount_bdev(fs_type, flags, dev_name, data, hfsplus_fill_super);
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations hfsplus_context_ops = {
+	.parse_param	= hfsplus_parse_param,
+	.get_tree	= hfsplus_get_tree,
+	.reconfigure	= hfsplus_reconfigure,
+	.free		= hfsplus_free_fc,
+};
+
+static int hfsplus_init_fs_context(struct fs_context *fc)
+{
+	struct hfsplus_sb_info *sbi;
+
+	sbi = kzalloc(sizeof(struct hfsplus_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
+		hfsplus_fill_defaults(sbi);
+
+	fc->s_fs_info = sbi;
+	fc->ops = &hfsplus_context_ops;
+
+	return 0;
 }
 
 static struct file_system_type hfsplus_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "hfsplus",
-	.mount		= hfsplus_mount,
 	.kill_sb	= kill_block_super,
 	.fs_flags	= FS_REQUIRES_DEV,
+	.init_fs_context = hfsplus_init_fs_context,
 };
 MODULE_ALIAS_FS("hfsplus");