Merge tag 'vfs-6.15-rc1.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs mount API updates from Christian Brauner:
 "This converts the remaining pseudo filesystems to the new mount api.

  The sysv conversion is a bit gratuitous because we remove sysv in
  another pull request. But if we have to revert the removal we at least
  will have it converted to the new mount api already"

* tag 'vfs-6.15-rc1.mount.api' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  sysv: convert sysv to use the new mount api
  vfs: remove some unused old mount api code
  devtmpfs: replace ->mount with ->get_tree in public instance
  vfs: Convert devpts to use the new mount API
  pstore: convert to the new mount API

7 files changed, 287 insertions, 271 deletions

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index b848764ef018..03a7c7902fcd 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -63,22 +63,6 @@ __setup("devtmpfs.mount=", mount_param);
 
 static struct vfsmount *mnt;
 
-static struct dentry *public_dev_mount(struct file_system_type *fs_type, int flags,
-		      const char *dev_name, void *data)
-{
-	struct super_block *s = mnt->mnt_sb;
-	int err;
-
-	atomic_inc(&s->s_active);
-	down_write(&s->s_umount);
-	err = reconfigure_single(s, flags, data);
-	if (err < 0) {
-		deactivate_locked_super(s);
-		return ERR_PTR(err);
-	}
-	return dget(s->s_root);
-}
-
 static struct file_system_type internal_fs_type = {
 	.name = "devtmpfs",
 #ifdef CONFIG_TMPFS
@@ -89,9 +73,40 @@ static struct file_system_type internal_fs_type = {
 	.kill_sb = kill_litter_super,
 };
 
+/* Simply take a ref on the existing mount */
+static int devtmpfs_get_tree(struct fs_context *fc)
+{
+	struct super_block *sb = mnt->mnt_sb;
+
+	atomic_inc(&sb->s_active);
+	down_write(&sb->s_umount);
+	fc->root = dget(sb->s_root);
+	return 0;
+}
+
+/* Ops are filled in during init depending on underlying shmem or ramfs type */
+struct fs_context_operations devtmpfs_context_ops = {};
+
+/* Call the underlying initialization and set to our ops */
+static int devtmpfs_init_fs_context(struct fs_context *fc)
+{
+	int ret;
+#ifdef CONFIG_TMPFS
+	ret = shmem_init_fs_context(fc);
+#else
+	ret = ramfs_init_fs_context(fc);
+#endif
+	if (ret < 0)
+		return ret;
+
+	fc->ops = &devtmpfs_context_ops;
+
+	return 0;
+}
+
 static struct file_system_type dev_fs_type = {
 	.name = "devtmpfs",
-	.mount = public_dev_mount,
+	.init_fs_context = devtmpfs_init_fs_context,
 };
 
 static int devtmpfs_submit_req(struct req *req, const char *tmp)
@@ -443,6 +458,31 @@ static int __ref devtmpfsd(void *p)
 }
 
 /*
+ * Get the underlying (shmem/ramfs) context ops to build ours
+ */
+static int devtmpfs_configure_context(void)
+{
+	struct fs_context *fc;
+
+	fc = fs_context_for_reconfigure(mnt->mnt_root, mnt->mnt_sb->s_flags,
+					MS_RMT_MASK);
+	if (IS_ERR(fc))
+		return PTR_ERR(fc);
+
+	/* Set up devtmpfs_context_ops based on underlying type */
+	devtmpfs_context_ops.free	      = fc->ops->free;
+	devtmpfs_context_ops.dup	      = fc->ops->dup;
+	devtmpfs_context_ops.parse_param      = fc->ops->parse_param;
+	devtmpfs_context_ops.parse_monolithic = fc->ops->parse_monolithic;
+	devtmpfs_context_ops.get_tree	      = &devtmpfs_get_tree;
+	devtmpfs_context_ops.reconfigure      = fc->ops->reconfigure;
+
+	put_fs_context(fc);
+
+	return 0;
+}
+
+/*
  * Create devtmpfs instance, driver-core devices will add their device
  * nodes here.
  */
@@ -456,6 +496,13 @@ int __init devtmpfs_init(void)
 		pr_err("unable to create devtmpfs %ld\n", PTR_ERR(mnt));
 		return PTR_ERR(mnt);
 	}
+
+	err = devtmpfs_configure_context();
+	if (err) {
+		pr_err("unable to configure devtmpfs type %d\n", err);
+		return err;
+	}
+
 	err = register_filesystem(&dev_fs_type);
 	if (err) {
 		pr_err("unable to register devtmpfs type %d\n", err);
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 1096ff8562fa..42e4d6eeb29f 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -12,6 +12,8 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/sched.h>
 #include <linux/namei.h>
 #include <linux/slab.h>
@@ -21,7 +23,6 @@
 #include <linux/magic.h>
 #include <linux/idr.h>
 #include <linux/devpts_fs.h>
-#include <linux/parser.h>
 #include <linux/fsnotify.h>
 #include <linux/seq_file.h>
 
@@ -87,14 +88,14 @@ enum {
 	Opt_err
 };
 
-static const match_table_t tokens = {
-	{Opt_uid, "uid=%u"},
-	{Opt_gid, "gid=%u"},
-	{Opt_mode, "mode=%o"},
-	{Opt_ptmxmode, "ptmxmode=%o"},
-	{Opt_newinstance, "newinstance"},
-	{Opt_max, "max=%d"},
-	{Opt_err, NULL}
+static const struct fs_parameter_spec devpts_param_specs[] = {
+	fsparam_u32	("gid",		Opt_gid),
+	fsparam_s32	("max",		Opt_max),
+	fsparam_u32oct	("mode",	Opt_mode),
+	fsparam_flag	("newinstance",	Opt_newinstance),
+	fsparam_u32oct	("ptmxmode",	Opt_ptmxmode),
+	fsparam_u32	("uid",		Opt_uid),
+	{}
 };
 
 struct pts_fs_info {
@@ -214,93 +215,48 @@ void devpts_release(struct pts_fs_info *fsi)
 	deactivate_super(fsi->sb);
 }
 
-#define PARSE_MOUNT	0
-#define PARSE_REMOUNT	1
-
 /*
- * parse_mount_options():
- *	Set @opts to mount options specified in @data. If an option is not
- *	specified in @data, set it to its default value.
- *
- * Note: @data may be NULL (in which case all options are set to default).
+ * devpts_parse_param - Parse mount parameters
  */
-static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
+static int devpts_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	char *p;
-	kuid_t uid;
-	kgid_t gid;
-
-	opts->setuid  = 0;
-	opts->setgid  = 0;
-	opts->uid     = GLOBAL_ROOT_UID;
-	opts->gid     = GLOBAL_ROOT_GID;
-	opts->mode    = DEVPTS_DEFAULT_MODE;
-	opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
-	opts->max     = NR_UNIX98_PTY_MAX;
-
-	/* Only allow instances mounted from the initial mount
-	 * namespace to tap the reserve pool of ptys.
-	 */
-	if (op == PARSE_MOUNT)
-		opts->reserve =
-			(current->nsproxy->mnt_ns == init_task.nsproxy->mnt_ns);
-
-	while ((p = strsep(&data, ",")) != NULL) {
-		substring_t args[MAX_OPT_ARGS];
-		int token;
-		int option;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, 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;
-			opts->uid = uid;
-			opts->setuid = 1;
-			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;
-			opts->gid = gid;
-			opts->setgid = 1;
-			break;
-		case Opt_mode:
-			if (match_octal(&args[0], &option))
-				return -EINVAL;
-			opts->mode = option & S_IALLUGO;
-			break;
-		case Opt_ptmxmode:
-			if (match_octal(&args[0], &option))
-				return -EINVAL;
-			opts->ptmxmode = option & S_IALLUGO;
-			break;
-		case Opt_newinstance:
-			break;
-		case Opt_max:
-			if (match_int(&args[0], &option) ||
-			    option < 0 || option > NR_UNIX98_PTY_MAX)
-				return -EINVAL;
-			opts->max = option;
-			break;
-		default:
-			pr_err("called with bogus options\n");
-			return -EINVAL;
-		}
+	struct pts_fs_info *fsi = fc->s_fs_info;
+	struct pts_mount_opts *opts = &fsi->mount_opts;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, devpts_param_specs, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		opts->uid = result.uid;
+		opts->setuid = 1;
+		break;
+	case Opt_gid:
+		opts->gid = result.gid;
+		opts->setgid = 1;
+		break;
+	case Opt_mode:
+		opts->mode = result.uint_32 & S_IALLUGO;
+		break;
+	case Opt_ptmxmode:
+		opts->ptmxmode = result.uint_32 & S_IALLUGO;
+		break;
+	case Opt_newinstance:
+		break;
+	case Opt_max:
+		if (result.uint_32 > NR_UNIX98_PTY_MAX)
+			return invalf(fc, "max out of range");
+		opts->max = result.uint_32;
+		break;
 	}
 
 	return 0;
 }
 
-static int mknod_ptmx(struct super_block *sb)
+static int mknod_ptmx(struct super_block *sb, struct fs_context *fc)
 {
 	int mode;
 	int rc = -ENOMEM;
@@ -362,13 +318,23 @@ static void update_ptmx_mode(struct pts_fs_info *fsi)
 	}
 }
 
-static int devpts_remount(struct super_block *sb, int *flags, char *data)
+static int devpts_reconfigure(struct fs_context *fc)
 {
-	int err;
-	struct pts_fs_info *fsi = DEVPTS_SB(sb);
-	struct pts_mount_opts *opts = &fsi->mount_opts;
+	struct pts_fs_info *fsi = DEVPTS_SB(fc->root->d_sb);
+	struct pts_fs_info *new = fc->s_fs_info;
 
-	err = parse_mount_options(data, PARSE_REMOUNT, opts);
+	/* Apply the revised options.  We don't want to change ->reserve.
+	 * Ideally, we'd update each option conditionally on it having been
+	 * explicitly changed, but the default is to reset everything so that
+	 * would break UAPI...
+	 */
+	fsi->mount_opts.setuid		= new->mount_opts.setuid;
+	fsi->mount_opts.setgid		= new->mount_opts.setgid;
+	fsi->mount_opts.uid		= new->mount_opts.uid;
+	fsi->mount_opts.gid		= new->mount_opts.gid;
+	fsi->mount_opts.mode		= new->mount_opts.mode;
+	fsi->mount_opts.ptmxmode	= new->mount_opts.ptmxmode;
+	fsi->mount_opts.max		= new->mount_opts.max;
 
 	/*
 	 * parse_mount_options() restores options to default values
@@ -378,7 +344,7 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
 	 */
 	update_ptmx_mode(fsi);
 
-	return err;
+	return 0;
 }
 
 static int devpts_show_options(struct seq_file *seq, struct dentry *root)
@@ -402,31 +368,13 @@ static int devpts_show_options(struct seq_file *seq, struct dentry *root)
 
 static const struct super_operations devpts_sops = {
 	.statfs		= simple_statfs,
-	.remount_fs	= devpts_remount,
 	.show_options	= devpts_show_options,
 };
 
-static void *new_pts_fs_info(struct super_block *sb)
-{
-	struct pts_fs_info *fsi;
-
-	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);
-	if (!fsi)
-		return NULL;
-
-	ida_init(&fsi->allocated_ptys);
-	fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
-	fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
-	fsi->sb = sb;
-
-	return fsi;
-}
-
-static int
-devpts_fill_super(struct super_block *s, void *data, int silent)
+static int devpts_fill_super(struct super_block *s, struct fs_context *fc)
 {
+	struct pts_fs_info *fsi = DEVPTS_SB(s);
 	struct inode *inode;
-	int error;
 
 	s->s_iflags &= ~SB_I_NODEV;
 	s->s_blocksize = 1024;
@@ -435,20 +383,11 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
 	s->s_op = &devpts_sops;
 	s->s_d_op = &simple_dentry_operations;
 	s->s_time_gran = 1;
+	fsi->sb = s;
 
-	error = -ENOMEM;
-	s->s_fs_info = new_pts_fs_info(s);
-	if (!s->s_fs_info)
-		goto fail;
-
-	error = parse_mount_options(data, PARSE_MOUNT, &DEVPTS_SB(s)->mount_opts);
-	if (error)
-		goto fail;
-
-	error = -ENOMEM;
 	inode = new_inode(s);
 	if (!inode)
-		goto fail;
+		return -ENOMEM;
 	inode->i_ino = 1;
 	simple_inode_init_ts(inode);
 	inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
@@ -459,31 +398,60 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
 	s->s_root = d_make_root(inode);
 	if (!s->s_root) {
 		pr_err("get root dentry failed\n");
-		goto fail;
+		return -ENOMEM;
 	}
 
-	error = mknod_ptmx(s);
-	if (error)
-		goto fail_dput;
-
-	return 0;
-fail_dput:
-	dput(s->s_root);
-	s->s_root = NULL;
-fail:
-	return error;
+	return mknod_ptmx(s, fc);
 }
 
 /*
- * devpts_mount()
+ * devpts_get_tree()
  *
  *     Mount a new (private) instance of devpts.  PTYs created in this
  *     instance are independent of the PTYs in other devpts instances.
  */
-static struct dentry *devpts_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int devpts_get_tree(struct fs_context *fc)
+{
+	return get_tree_nodev(fc, devpts_fill_super);
+}
+
+static void devpts_free_fc(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations devpts_context_ops = {
+	.free		= devpts_free_fc,
+	.parse_param	= devpts_parse_param,
+	.get_tree	= devpts_get_tree,
+	.reconfigure	= devpts_reconfigure,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int devpts_init_fs_context(struct fs_context *fc)
 {
-	return mount_nodev(fs_type, flags, data, devpts_fill_super);
+	struct pts_fs_info *fsi;
+
+	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);
+	if (!fsi)
+		return -ENOMEM;
+
+	ida_init(&fsi->allocated_ptys);
+	fsi->mount_opts.uid     = GLOBAL_ROOT_UID;
+	fsi->mount_opts.gid     = GLOBAL_ROOT_GID;
+	fsi->mount_opts.mode    = DEVPTS_DEFAULT_MODE;
+	fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
+	fsi->mount_opts.max     = NR_UNIX98_PTY_MAX;
+
+	if (fc->purpose == FS_CONTEXT_FOR_MOUNT &&
+	    current->nsproxy->mnt_ns == init_task.nsproxy->mnt_ns)
+		fsi->mount_opts.reserve = true;
+
+	fc->s_fs_info = fsi;
+	fc->ops = &devpts_context_ops;
+	return 0;
 }
 
 static void devpts_kill_sb(struct super_block *sb)
@@ -498,7 +466,8 @@ static void devpts_kill_sb(struct super_block *sb)
 
 static struct file_system_type devpts_fs_type = {
 	.name		= "devpts",
-	.mount		= devpts_mount,
+	.init_fs_context = devpts_init_fs_context,
+	.parameters	= devpts_param_specs,
 	.kill_sb	= devpts_kill_sb,
 	.fs_flags	= FS_USERNS_MOUNT,
 };
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 56815799ce79..034143869421 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -14,10 +14,10 @@
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/string.h>
-#include <linux/mount.h>
 #include <linux/seq_file.h>
 #include <linux/ramfs.h>
-#include <linux/parser.h>
+#include <linux/fs_parser.h>
+#include <linux/fs_context.h>
 #include <linux/sched.h>
 #include <linux/magic.h>
 #include <linux/pstore.h>
@@ -226,37 +226,38 @@ static struct inode *pstore_get_inode(struct super_block *sb)
 }
 
 enum {
-	Opt_kmsg_bytes, Opt_err
+	Opt_kmsg_bytes
 };
 
-static const match_table_t tokens = {
-	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
-	{Opt_err, NULL}
+static const struct fs_parameter_spec pstore_param_spec[] = {
+	fsparam_u32	("kmsg_bytes",	Opt_kmsg_bytes),
+	{}
 };
 
-static void parse_options(char *options)
-{
-	char		*p;
-	substring_t	args[MAX_OPT_ARGS];
-	int		option;
-
-	if (!options)
-		return;
+struct pstore_context {
+	unsigned int kmsg_bytes;
+};
 
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
+static int pstore_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct pstore_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
 
-		if (!*p)
-			continue;
+	opt = fs_parse(fc, pstore_param_spec, param, &result);
+	/* pstore has historically ignored invalid kmsg_bytes param */
+	if (opt < 0)
+		return 0;
 
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_kmsg_bytes:
-			if (!match_int(&args[0], &option))
-				pstore_set_kmsg_bytes(option);
-			break;
-		}
+	switch (opt) {
+	case Opt_kmsg_bytes:
+		ctx->kmsg_bytes = result.uint_32;
+		break;
+	default:
+		return -EINVAL;
 	}
+
+	return 0;
 }
 
 /*
@@ -269,10 +270,12 @@ static int pstore_show_options(struct seq_file *m, struct dentry *root)
 	return 0;
 }
 
-static int pstore_remount(struct super_block *sb, int *flags, char *data)
+static int pstore_reconfigure(struct fs_context *fc)
 {
-	sync_filesystem(sb);
-	parse_options(data);
+	struct pstore_context *ctx = fc->fs_private;
+
+	sync_filesystem(fc->root->d_sb);
+	pstore_set_kmsg_bytes(ctx->kmsg_bytes);
 
 	return 0;
 }
@@ -281,7 +284,6 @@ static const struct super_operations pstore_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
 	.evict_inode	= pstore_evict_inode,
-	.remount_fs	= pstore_remount,
 	.show_options	= pstore_show_options,
 };
 
@@ -406,8 +408,9 @@ void pstore_get_records(int quiet)
 	inode_unlock(d_inode(root));
 }
 
-static int pstore_fill_super(struct super_block *sb, void *data, int silent)
+static int pstore_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct pstore_context *ctx = fc->fs_private;
 	struct inode *inode;
 
 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
@@ -417,7 +420,7 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_op		= &pstore_ops;
 	sb->s_time_gran		= 1;
 
-	parse_options(data);
+	pstore_set_kmsg_bytes(ctx->kmsg_bytes);
 
 	inode = pstore_get_inode(sb);
 	if (inode) {
@@ -438,12 +441,26 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-static struct dentry *pstore_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int pstore_get_tree(struct fs_context *fc)
+{
+	if (fc->root)
+		return pstore_reconfigure(fc);
+
+	return get_tree_single(fc, pstore_fill_super);
+}
+
+static void pstore_free_fc(struct fs_context *fc)
 {
-	return mount_single(fs_type, flags, data, pstore_fill_super);
+	kfree(fc->fs_private);
 }
 
+static const struct fs_context_operations pstore_context_ops = {
+	.parse_param	= pstore_parse_param,
+	.get_tree	= pstore_get_tree,
+	.reconfigure	= pstore_reconfigure,
+	.free		= pstore_free_fc,
+};
+
 static void pstore_kill_sb(struct super_block *sb)
 {
 	guard(mutex)(&pstore_sb_lock);
@@ -456,11 +473,33 @@ static void pstore_kill_sb(struct super_block *sb)
 	INIT_LIST_HEAD(&records_list);
 }
 
+static int pstore_init_fs_context(struct fs_context *fc)
+{
+	struct pstore_context *ctx;
+
+	ctx = kzalloc(sizeof(struct pstore_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	/*
+	 * Global kmsg_bytes is initialized to default, and updated
+	 * every time we (re)mount the single-sb filesystem with the
+	 * option specified.
+	 */
+	ctx->kmsg_bytes = kmsg_bytes;
+
+	fc->fs_private = ctx;
+	fc->ops = &pstore_context_ops;
+
+	return 0;
+}
+
 static struct file_system_type pstore_fs_type = {
 	.owner          = THIS_MODULE,
 	.name		= "pstore",
-	.mount		= pstore_mount,
 	.kill_sb	= pstore_kill_sb,
+	.init_fs_context = pstore_init_fs_context,
+	.parameters	= pstore_param_spec,
 };
 
 int __init pstore_init_fs(void)
diff --git a/fs/super.c b/fs/super.c
index 5a7db4a556e3..723176dee229 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1737,61 +1737,6 @@ struct dentry *mount_nodev(struct file_system_type *fs_type,
 }
 EXPORT_SYMBOL(mount_nodev);
 
-int reconfigure_single(struct super_block *s,
-		       int flags, void *data)
-{
-	struct fs_context *fc;
-	int ret;
-
-	/* The caller really need to be passing fc down into mount_single(),
-	 * then a chunk of this can be removed.  [Bollocks -- AV]
-	 * Better yet, reconfiguration shouldn't happen, but rather the second
-	 * mount should be rejected if the parameters are not compatible.
-	 */
-	fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
-	if (IS_ERR(fc))
-		return PTR_ERR(fc);
-
-	ret = parse_monolithic_mount_data(fc, data);
-	if (ret < 0)
-		goto out;
-
-	ret = reconfigure_super(fc);
-out:
-	put_fs_context(fc);
-	return ret;
-}
-
-static int compare_single(struct super_block *s, void *p)
-{
-	return 1;
-}
-
-struct dentry *mount_single(struct file_system_type *fs_type,
-	int flags, void *data,
-	int (*fill_super)(struct super_block *, void *, int))
-{
-	struct super_block *s;
-	int error;
-
-	s = sget(fs_type, compare_single, set_anon_super, flags, NULL);
-	if (IS_ERR(s))
-		return ERR_CAST(s);
-	if (!s->s_root) {
-		error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
-		if (!error)
-			s->s_flags |= SB_ACTIVE;
-	} else {
-		error = reconfigure_single(s, flags, data);
-	}
-	if (unlikely(error)) {
-		deactivate_locked_super(s);
-		return ERR_PTR(error);
-	}
-	return dget(s->s_root);
-}
-EXPORT_SYMBOL(mount_single);
-
 /**
  * vfs_get_tree - Get the mountable root
  * @fc: The superblock configuration context.
diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 5c0d07ddbda2..03be9f1b7802 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/buffer_head.h>
+#include <linux/fs_context.h>
 #include "sysv.h"
 
 /*
@@ -349,12 +350,13 @@ static int complete_read_super(struct super_block *sb, int silent, int size)
 	return 1;
 }
 
-static int sysv_fill_super(struct super_block *sb, void *data, int silent)
+static int sysv_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct buffer_head *bh1, *bh = NULL;
 	struct sysv_sb_info *sbi;
 	unsigned long blocknr;
 	int size = 0, i;
+	int silent = fc->sb_flags & SB_SILENT;
 	
 	BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block));
 	BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block));
@@ -471,10 +473,11 @@ static int v7_sanity_check(struct super_block *sb, struct buffer_head *bh)
 	return 1;
 }
 
-static int v7_fill_super(struct super_block *sb, void *data, int silent)
+static int v7_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct sysv_sb_info *sbi;
 	struct buffer_head *bh;
+	int silent = fc->sb_flags & SB_SILENT;
 
 	BUILD_BUG_ON(sizeof(struct v7_super_block) != 440);
 	BUILD_BUG_ON(sizeof(struct sysv_inode) != 64);
@@ -528,33 +531,51 @@ failed:
 
 /* Every kernel module contains stuff like this. */
 
-static struct dentry *sysv_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int sysv_get_tree(struct fs_context *fc)
 {
-	return mount_bdev(fs_type, flags, dev_name, data, sysv_fill_super);
+	return get_tree_bdev(fc, sysv_fill_super);
 }
 
-static struct dentry *v7_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int v7_get_tree(struct fs_context *fc)
 {
-	return mount_bdev(fs_type, flags, dev_name, data, v7_fill_super);
+	return get_tree_bdev(fc, v7_fill_super);
+}
+
+static const struct fs_context_operations sysv_context_ops = {
+	.get_tree	= sysv_get_tree,
+};
+
+static const struct fs_context_operations v7_context_ops = {
+	.get_tree	= v7_get_tree,
+};
+
+static int sysv_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &sysv_context_ops;
+	return 0;
+}
+
+static int v7_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &v7_context_ops;
+	return 0;
 }
 
 static struct file_system_type sysv_fs_type = {
-	.owner		= THIS_MODULE,
-	.name		= "sysv",
-	.mount		= sysv_mount,
-	.kill_sb	= kill_block_super,
-	.fs_flags	= FS_REQUIRES_DEV,
+	.owner			= THIS_MODULE,
+	.name			= "sysv",
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+	.init_fs_context	= sysv_init_fs_context,
 };
 MODULE_ALIAS_FS("sysv");
 
 static struct file_system_type v7_fs_type = {
-	.owner		= THIS_MODULE,
-	.name		= "v7",
-	.mount		= v7_mount,
-	.kill_sb	= kill_block_super,
-	.fs_flags	= FS_REQUIRES_DEV,
+	.owner			= THIS_MODULE,
+	.name			= "v7",
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+	.init_fs_context	= v7_init_fs_context,
 };
 MODULE_ALIAS_FS("v7");
 MODULE_ALIAS("v7");
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2788df98080f..b570138ff114 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2653,9 +2653,6 @@ static inline bool is_mgtime(const struct inode *inode)
 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data,
 	int (*fill_super)(struct super_block *, void *, int));
-extern struct dentry *mount_single(struct file_system_type *fs_type,
-	int flags, void *data,
-	int (*fill_super)(struct super_block *, void *, int));
 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
 	int flags, void *data,
 	int (*fill_super)(struct super_block *, void *, int));
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 4b4bfef6f053..a19e4bd32e4d 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -144,8 +144,6 @@ extern void put_fs_context(struct fs_context *fc);
 extern int vfs_parse_fs_param_source(struct fs_context *fc,
 				     struct fs_parameter *param);
 extern void fc_drop_locked(struct fs_context *fc);
-int reconfigure_single(struct super_block *s,
-		       int flags, void *data);
 
 extern int get_tree_nodev(struct fs_context *fc,
 			 int (*fill_super)(struct super_block *sb,