Merge branch 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc mount API conversions from Al Viro:
 "Conversions to new API for shmem and friends and for mount_mtd()-using
  filesystems.

  As for the rest of the mount API conversions in -next, some of them
  belong in the individual trees (e.g. binderfs one should definitely go
  through android folks, after getting redone on top of their changes).
  I'm going to drop those and send the rest (trivial ones + stuff ACKed
  by maintainers) in a separate series - by that point they are
  independent from each other.

  Some stuff has already migrated into individual trees (NFS conversion,
  for example, or FUSE stuff, etc.); those presumably will go through
  the regular merges from corresponding trees."

* 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Make fs_parse() handle fs_param_is_fd-type params better
  vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API
  shmem_parse_one(): switch to use of fs_parse()
  shmem_parse_options(): take handling a single option into a helper
  shmem_parse_options(): don't bother with mpol in separate variable
  shmem_parse_options(): use a separate structure to keep the results
  make shmem_fill_super() static
  make ramfs_fill_super() static
  devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()
  vfs: Convert squashfs to use the new mount API
  mtd: Kill mount_mtd()
  vfs: Convert jffs2 to use the new mount API
  vfs: Convert cramfs to use the new mount API
  vfs: Convert romfs to use the new mount API
  vfs: Add a single-or-reconfig keying to vfs_get_super()

9 files changed, 320 insertions, 244 deletions

diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 4d1d8b7761ed..d12ea28836a5 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -24,6 +24,7 @@
 #include <linux/blkdev.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/super.h>
+#include <linux/fs_context.h>
 #include <linux/slab.h>
 #include <linux/vfs.h>
 #include <linux/mutex.h>
@@ -506,18 +507,19 @@ static void cramfs_kill_sb(struct super_block *sb)
 	kfree(sbi);
 }
 
-static int cramfs_remount(struct super_block *sb, int *flags, char *data)
+static int cramfs_reconfigure(struct fs_context *fc)
 {
-	sync_filesystem(sb);
-	*flags |= SB_RDONLY;
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_RDONLY;
 	return 0;
 }
 
-static int cramfs_read_super(struct super_block *sb,
-			     struct cramfs_super *super, int silent)
+static int cramfs_read_super(struct super_block *sb, struct fs_context *fc,
+			     struct cramfs_super *super)
 {
 	struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
 	unsigned long root_offset;
+	bool silent = fc->sb_flags & SB_SILENT;
 
 	/* We don't know the real size yet */
 	sbi->size = PAGE_SIZE;
@@ -532,7 +534,7 @@ static int cramfs_read_super(struct super_block *sb,
 		/* check for wrong endianness */
 		if (super->magic == CRAMFS_MAGIC_WEND) {
 			if (!silent)
-				pr_err("wrong endianness\n");
+				errorf(fc, "cramfs: wrong endianness");
 			return -EINVAL;
 		}
 
@@ -544,22 +546,22 @@ static int cramfs_read_super(struct super_block *sb,
 		mutex_unlock(&read_mutex);
 		if (super->magic != CRAMFS_MAGIC) {
 			if (super->magic == CRAMFS_MAGIC_WEND && !silent)
-				pr_err("wrong endianness\n");
+				errorf(fc, "cramfs: wrong endianness");
 			else if (!silent)
-				pr_err("wrong magic\n");
+				errorf(fc, "cramfs: wrong magic");
 			return -EINVAL;
 		}
 	}
 
 	/* get feature flags first */
 	if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
-		pr_err("unsupported filesystem features\n");
+		errorf(fc, "cramfs: unsupported filesystem features");
 		return -EINVAL;
 	}
 
 	/* Check that the root inode is in a sane state */
 	if (!S_ISDIR(super->root.mode)) {
-		pr_err("root is not a directory\n");
+		errorf(fc, "cramfs: root is not a directory");
 		return -EINVAL;
 	}
 	/* correct strange, hard-coded permissions of mkcramfs */
@@ -578,12 +580,12 @@ static int cramfs_read_super(struct super_block *sb,
 	sbi->magic = super->magic;
 	sbi->flags = super->flags;
 	if (root_offset == 0)
-		pr_info("empty filesystem");
+		infof(fc, "cramfs: empty filesystem");
 	else if (!(super->flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
 		 ((root_offset != sizeof(struct cramfs_super)) &&
 		  (root_offset != 512 + sizeof(struct cramfs_super))))
 	{
-		pr_err("bad root offset %lu\n", root_offset);
+		errorf(fc, "cramfs: bad root offset %lu", root_offset);
 		return -EINVAL;
 	}
 
@@ -609,8 +611,7 @@ static int cramfs_finalize_super(struct super_block *sb,
 	return 0;
 }
 
-static int cramfs_blkdev_fill_super(struct super_block *sb, void *data,
-				    int silent)
+static int cramfs_blkdev_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct cramfs_sb_info *sbi;
 	struct cramfs_super super;
@@ -625,14 +626,13 @@ static int cramfs_blkdev_fill_super(struct super_block *sb, void *data,
 	for (i = 0; i < READ_BUFFERS; i++)
 		buffer_blocknr[i] = -1;
 
-	err = cramfs_read_super(sb, &super, silent);
+	err = cramfs_read_super(sb, fc, &super);
 	if (err)
 		return err;
 	return cramfs_finalize_super(sb, &super.root);
 }
 
-static int cramfs_mtd_fill_super(struct super_block *sb, void *data,
-				 int silent)
+static int cramfs_mtd_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct cramfs_sb_info *sbi;
 	struct cramfs_super super;
@@ -654,7 +654,7 @@ static int cramfs_mtd_fill_super(struct super_block *sb, void *data,
 
 	pr_info("checking physical address %pap for linear cramfs image\n",
 		&sbi->linear_phys_addr);
-	err = cramfs_read_super(sb, &super, silent);
+	err = cramfs_read_super(sb, fc, &super);
 	if (err)
 		return err;
 
@@ -949,32 +949,41 @@ static const struct inode_operations cramfs_dir_inode_operations = {
 };
 
 static const struct super_operations cramfs_ops = {
-	.remount_fs	= cramfs_remount,
 	.statfs		= cramfs_statfs,
 };
 
-static struct dentry *cramfs_mount(struct file_system_type *fs_type, int flags,
-				   const char *dev_name, void *data)
+static int cramfs_get_tree(struct fs_context *fc)
 {
-	struct dentry *ret = ERR_PTR(-ENOPROTOOPT);
+	int ret = -ENOPROTOOPT;
 
 	if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
-		ret = mount_mtd(fs_type, flags, dev_name, data,
-				cramfs_mtd_fill_super);
-		if (!IS_ERR(ret))
+		ret = get_tree_mtd(fc, cramfs_mtd_fill_super);
+		if (ret < 0)
 			return ret;
 	}
-	if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV)) {
-		ret = mount_bdev(fs_type, flags, dev_name, data,
-				 cramfs_blkdev_fill_super);
-	}
+	if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
+		ret = get_tree_bdev(fc, cramfs_blkdev_fill_super);
 	return ret;
 }
 
+static const struct fs_context_operations cramfs_context_ops = {
+	.get_tree	= cramfs_get_tree,
+	.reconfigure	= cramfs_reconfigure,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int cramfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &cramfs_context_ops;
+	return 0;
+}
+
 static struct file_system_type cramfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "cramfs",
-	.mount		= cramfs_mount,
+	.init_fs_context = cramfs_init_fs_context,
 	.kill_sb	= cramfs_kill_sb,
 	.fs_flags	= FS_REQUIRES_DEV,
 };
diff --git a/fs/fs_parser.c b/fs/fs_parser.c
index 460ea4206fa2..d1930adce68d 100644
--- a/fs/fs_parser.c
+++ b/fs/fs_parser.c
@@ -204,9 +204,23 @@ int fs_parse(struct fs_context *fc,
 		goto okay;
 
 	case fs_param_is_fd: {
-		if (param->type != fs_value_is_file)
+		switch (param->type) {
+		case fs_value_is_string:
+			if (!result->has_value)
+				goto bad_value;
+
+			ret = kstrtouint(param->string, 0, &result->uint_32);
+			break;
+		case fs_value_is_file:
+			result->uint_32 = param->dirfd;
+			ret = 0;
+		default:
 			goto bad_value;
-		goto okay;
+		}
+
+		if (result->uint_32 > INT_MAX)
+			goto bad_value;
+		goto maybe_okay;
 	}
 
 	case fs_param_is_blockdev:
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index d0b59d03a7a9..05fe6cf5f1ac 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -17,6 +17,7 @@
 #include <linux/sched.h>
 #include <linux/cred.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/list.h>
 #include <linux/mtd/mtd.h>
 #include <linux/pagemap.h>
@@ -184,7 +185,7 @@ int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
 	if (ivalid & ATTR_SIZE && inode->i_size > iattr->ia_size) {
 		truncate_setsize(inode, iattr->ia_size);
 		inode->i_blocks = (inode->i_size + 511) >> 9;
-	}	
+	}
 
 	return 0;
 }
@@ -391,7 +392,7 @@ void jffs2_dirty_inode(struct inode *inode, int flags)
 	jffs2_do_setattr(inode, &iattr);
 }
 
-int jffs2_do_remount_fs(struct super_block *sb, int *flags, char *data)
+int jffs2_do_remount_fs(struct super_block *sb, struct fs_context *fc)
 {
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 
@@ -409,10 +410,10 @@ int jffs2_do_remount_fs(struct super_block *sb, int *flags, char *data)
 		mutex_unlock(&c->alloc_sem);
 	}
 
-	if (!(*flags & SB_RDONLY))
+	if (!(fc->sb_flags & SB_RDONLY))
 		jffs2_start_garbage_collect_thread(c);
 
-	*flags |= SB_NOATIME;
+	fc->sb_flags |= SB_NOATIME;
 	return 0;
 }
 
@@ -509,7 +510,7 @@ static int calculate_inocache_hashsize(uint32_t flash_size)
 	return hashsize;
 }
 
-int jffs2_do_fill_super(struct super_block *sb, void *data, int silent)
+int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct jffs2_sb_info *c;
 	struct inode *root_i;
@@ -524,11 +525,11 @@ int jffs2_do_fill_super(struct super_block *sb, void *data, int silent)
 
 #ifndef CONFIG_JFFS2_FS_WRITEBUFFER
 	if (c->mtd->type == MTD_NANDFLASH) {
-		pr_err("Cannot operate on NAND flash unless jffs2 NAND support is compiled in\n");
+		errorf(fc, "Cannot operate on NAND flash unless jffs2 NAND support is compiled in");
 		return -EINVAL;
 	}
 	if (c->mtd->type == MTD_DATAFLASH) {
-		pr_err("Cannot operate on DataFlash unless jffs2 DataFlash support is compiled in\n");
+		errorf(fc, "Cannot operate on DataFlash unless jffs2 DataFlash support is compiled in");
 		return -EINVAL;
 	}
 #endif
@@ -542,12 +543,12 @@ int jffs2_do_fill_super(struct super_block *sb, void *data, int silent)
 	 */
 	if ((c->sector_size * blocks) != c->flash_size) {
 		c->flash_size = c->sector_size * blocks;
-		pr_info("Flash size not aligned to erasesize, reducing to %dKiB\n",
-			c->flash_size / 1024);
+		infof(fc, "Flash size not aligned to erasesize, reducing to %dKiB",
+		      c->flash_size / 1024);
 	}
 
 	if (c->flash_size < 5*c->sector_size) {
-		pr_err("Too few erase blocks (%d)\n",
+		errorf(fc, "Too few erase blocks (%d)",
 		       c->flash_size / c->sector_size);
 		return -EINVAL;
 	}
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index bd3d5f0ddc34..21071fc2975d 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -172,8 +172,8 @@ void jffs2_dirty_inode(struct inode *inode, int flags);
 struct inode *jffs2_new_inode (struct inode *dir_i, umode_t mode,
 			       struct jffs2_raw_inode *ri);
 int jffs2_statfs (struct dentry *, struct kstatfs *);
-int jffs2_do_remount_fs(struct super_block *, int *, char *);
-int jffs2_do_fill_super(struct super_block *sb, void *data, int silent);
+int jffs2_do_remount_fs(struct super_block *sb, struct fs_context *fc);
+int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc);
 void jffs2_gc_release_inode(struct jffs2_sb_info *c,
 			    struct jffs2_inode_info *f);
 struct jffs2_inode_info *jffs2_gc_fetch_inode(struct jffs2_sb_info *c,
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");
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 733c6b4193dc..d82636e8eb65 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -36,6 +36,8 @@
 #include <linux/magic.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include "internal.h"
 
 struct ramfs_mount_opts {
@@ -175,62 +177,52 @@ static const struct super_operations ramfs_ops = {
 	.show_options	= ramfs_show_options,
 };
 
-enum {
+enum ramfs_param {
 	Opt_mode,
-	Opt_err
 };
 
-static const match_table_t tokens = {
-	{Opt_mode, "mode=%o"},
-	{Opt_err, NULL}
+static const struct fs_parameter_spec ramfs_param_specs[] = {
+	fsparam_u32oct("mode",	Opt_mode),
+	{}
 };
 
-static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts)
+const struct fs_parameter_description ramfs_fs_parameters = {
+	.name		= "ramfs",
+	.specs		= ramfs_param_specs,
+};
+
+static int ramfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	substring_t args[MAX_OPT_ARGS];
-	int option;
-	int token;
-	char *p;
-
-	opts->mode = RAMFS_DEFAULT_MODE;
-
-	while ((p = strsep(&data, ",")) != NULL) {
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_mode:
-			if (match_octal(&args[0], &option))
-				return -EINVAL;
-			opts->mode = option & S_IALLUGO;
-			break;
+	struct fs_parse_result result;
+	struct ramfs_fs_info *fsi = fc->s_fs_info;
+	int opt;
+
+	opt = fs_parse(fc, &ramfs_fs_parameters, param, &result);
+	if (opt < 0) {
 		/*
 		 * We might like to report bad mount options here;
 		 * but traditionally ramfs has ignored all mount options,
 		 * and as it is used as a !CONFIG_SHMEM simple substitute
 		 * for tmpfs, better continue to ignore other mount options.
 		 */
-		}
+		if (opt == -ENOPARAM)
+			opt = 0;
+		return opt;
+	}
+
+	switch (opt) {
+	case Opt_mode:
+		fsi->mount_opts.mode = result.uint_32 & S_IALLUGO;
+		break;
 	}
 
 	return 0;
 }
 
-int ramfs_fill_super(struct super_block *sb, void *data, int silent)
+static int ramfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
-	struct ramfs_fs_info *fsi;
+	struct ramfs_fs_info *fsi = sb->s_fs_info;
 	struct inode *inode;
-	int err;
-
-	fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
-	sb->s_fs_info = fsi;
-	if (!fsi)
-		return -ENOMEM;
-
-	err = ramfs_parse_options(data, &fsi->mount_opts);
-	if (err)
-		return err;
 
 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
 	sb->s_blocksize		= PAGE_SIZE;
@@ -247,10 +239,34 @@ int ramfs_fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 }
 
-struct dentry *ramfs_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int ramfs_get_tree(struct fs_context *fc)
 {
-	return mount_nodev(fs_type, flags, data, ramfs_fill_super);
+	return get_tree_nodev(fc, ramfs_fill_super);
+}
+
+static void ramfs_free_fc(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations ramfs_context_ops = {
+	.free		= ramfs_free_fc,
+	.parse_param	= ramfs_parse_param,
+	.get_tree	= ramfs_get_tree,
+};
+
+int ramfs_init_fs_context(struct fs_context *fc)
+{
+	struct ramfs_fs_info *fsi;
+
+	fsi = kzalloc(sizeof(*fsi), GFP_KERNEL);
+	if (!fsi)
+		return -ENOMEM;
+
+	fsi->mount_opts.mode = RAMFS_DEFAULT_MODE;
+	fc->s_fs_info = fsi;
+	fc->ops = &ramfs_context_ops;
+	return 0;
 }
 
 static void ramfs_kill_sb(struct super_block *sb)
@@ -261,7 +277,8 @@ static void ramfs_kill_sb(struct super_block *sb)
 
 static struct file_system_type ramfs_fs_type = {
 	.name		= "ramfs",
-	.mount		= ramfs_mount,
+	.init_fs_context = ramfs_init_fs_context,
+	.parameters	= &ramfs_fs_parameters,
 	.kill_sb	= ramfs_kill_sb,
 	.fs_flags	= FS_USERNS_MOUNT,
 };
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index a42c0e3079dc..e582d001f792 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -65,7 +65,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
 #include <linux/statfs.h>
@@ -423,10 +423,10 @@ static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 /*
  * remounting must involve read-only
  */
-static int romfs_remount(struct super_block *sb, int *flags, char *data)
+static int romfs_reconfigure(struct fs_context *fc)
 {
-	sync_filesystem(sb);
-	*flags |= SB_RDONLY;
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_RDONLY;
 	return 0;
 }
 
@@ -434,7 +434,6 @@ static const struct super_operations romfs_super_ops = {
 	.alloc_inode	= romfs_alloc_inode,
 	.free_inode	= romfs_free_inode,
 	.statfs		= romfs_statfs,
-	.remount_fs	= romfs_remount,
 };
 
 /*
@@ -457,7 +456,7 @@ static __u32 romfs_checksum(const void *data, int size)
 /*
  * fill in the superblock
  */
-static int romfs_fill_super(struct super_block *sb, void *data, int silent)
+static int romfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct romfs_super_block *rsb;
 	struct inode *root;
@@ -506,8 +505,8 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
 	    img_size < ROMFH_SIZE) {
-		if (!silent)
-			pr_warn("VFS: Can't find a romfs filesystem on dev %s.\n",
+		if (!(fc->sb_flags & SB_SILENT))
+			errorf(fc, "VFS: Can't find a romfs filesystem on dev %s.\n",
 			       sb->s_id);
 		goto error_rsb_inval;
 	}
@@ -520,7 +519,7 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 	storage = sb->s_mtd ? "MTD" : "the block layer";
 
 	len = strnlen(rsb->name, ROMFS_MAXFN);
-	if (!silent)
+	if (!(fc->sb_flags & SB_SILENT))
 		pr_notice("Mounting image '%*.*s' through %s\n",
 			  (unsigned) len, (unsigned) len, rsb->name, storage);
 
@@ -550,23 +549,34 @@ error_rsb:
 /*
  * get a superblock for mounting
  */
-static struct dentry *romfs_mount(struct file_system_type *fs_type,
-			int flags, const char *dev_name,
-			void *data)
+static int romfs_get_tree(struct fs_context *fc)
 {
-	struct dentry *ret = ERR_PTR(-EINVAL);
+	int ret = -EINVAL;
 
 #ifdef CONFIG_ROMFS_ON_MTD
-	ret = mount_mtd(fs_type, flags, dev_name, data, romfs_fill_super);
+	ret = get_tree_mtd(fc, romfs_fill_super);
 #endif
 #ifdef CONFIG_ROMFS_ON_BLOCK
-	if (ret == ERR_PTR(-EINVAL))
-		ret = mount_bdev(fs_type, flags, dev_name, data,
-				  romfs_fill_super);
+	if (ret == -EINVAL)
+		ret = get_tree_bdev(fc, romfs_fill_super);
 #endif
 	return ret;
 }
 
+static const struct fs_context_operations romfs_context_ops = {
+	.get_tree	= romfs_get_tree,
+	.reconfigure	= romfs_reconfigure,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int romfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &romfs_context_ops;
+	return 0;
+}
+
 /*
  * destroy a romfs superblock in the appropriate manner
  */
@@ -589,7 +599,7 @@ static void romfs_kill_sb(struct super_block *sb)
 static struct file_system_type romfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "romfs",
-	.mount		= romfs_mount,
+	.init_fs_context = romfs_init_fs_context,
 	.kill_sb	= romfs_kill_sb,
 	.fs_flags	= FS_REQUIRES_DEV,
 };
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index a9e9837617a9..0cc4ceec0562 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -17,6 +17,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/fs.h>
+#include <linux/fs_context.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
@@ -36,26 +37,27 @@
 static struct file_system_type squashfs_fs_type;
 static const struct super_operations squashfs_super_ops;
 
-static const struct squashfs_decompressor *supported_squashfs_filesystem(short
-	major, short minor, short id)
+static const struct squashfs_decompressor *supported_squashfs_filesystem(
+	struct fs_context *fc,
+	short major, short minor, short id)
 {
 	const struct squashfs_decompressor *decompressor;
 
 	if (major < SQUASHFS_MAJOR) {
-		ERROR("Major/Minor mismatch, older Squashfs %d.%d "
-			"filesystems are unsupported\n", major, minor);
+		errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d "
+		       "filesystems are unsupported", major, minor);
 		return NULL;
 	} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
-		ERROR("Major/Minor mismatch, trying to mount newer "
-			"%d.%d filesystem\n", major, minor);
-		ERROR("Please update your kernel\n");
+		errorf(fc, "Major/Minor mismatch, trying to mount newer "
+		       "%d.%d filesystem", major, minor);
+		errorf(fc, "Please update your kernel");
 		return NULL;
 	}
 
 	decompressor = squashfs_lookup_decompressor(id);
 	if (!decompressor->supported) {
-		ERROR("Filesystem uses \"%s\" compression. This is not "
-			"supported\n", decompressor->name);
+		errorf(fc, "Filesystem uses \"%s\" compression. This is not supported",
+		       decompressor->name);
 		return NULL;
 	}
 
@@ -63,7 +65,7 @@ static const struct squashfs_decompressor *supported_squashfs_filesystem(short
 }
 
 
-static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
+static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct squashfs_sb_info *msblk;
 	struct squashfs_super_block *sblk = NULL;
@@ -98,7 +100,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
 
 	if (IS_ERR(sblk)) {
-		ERROR("unable to read squashfs_super_block\n");
+		errorf(fc, "unable to read squashfs_super_block");
 		err = PTR_ERR(sblk);
 		sblk = NULL;
 		goto failed_mount;
@@ -109,14 +111,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	/* Check it is a SQUASHFS superblock */
 	sb->s_magic = le32_to_cpu(sblk->s_magic);
 	if (sb->s_magic != SQUASHFS_MAGIC) {
-		if (!silent)
-			ERROR("Can't find a SQUASHFS superblock on %pg\n",
-						sb->s_bdev);
+		if (!(fc->sb_flags & SB_SILENT))
+			errorf(fc, "Can't find a SQUASHFS superblock on %pg",
+			       sb->s_bdev);
 		goto failed_mount;
 	}
 
 	/* Check the MAJOR & MINOR versions and lookup compression type */
 	msblk->decompressor = supported_squashfs_filesystem(
+			fc,
 			le16_to_cpu(sblk->s_major),
 			le16_to_cpu(sblk->s_minor),
 			le16_to_cpu(sblk->compression));
@@ -133,15 +136,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	/* Check block size for sanity */
 	msblk->block_size = le32_to_cpu(sblk->block_size);
 	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
-		goto failed_mount;
+		goto insanity;
 
 	/*
 	 * Check the system page size is not larger than the filesystem
 	 * block size (by default 128K).  This is currently not supported.
 	 */
 	if (PAGE_SIZE > msblk->block_size) {
-		ERROR("Page size > filesystem block size (%d).  This is "
-			"currently not supported!\n", msblk->block_size);
+		errorf(fc, "Page size > filesystem block size (%d).  This is "
+		       "currently not supported!", msblk->block_size);
 		goto failed_mount;
 	}
 
@@ -152,12 +155,12 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* Check that block_size and block_log match */
 	if (msblk->block_size != (1 << msblk->block_log))
-		goto failed_mount;
+		goto insanity;
 
 	/* Check the root inode for sanity */
 	root_inode = le64_to_cpu(sblk->root_inode);
 	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
-		goto failed_mount;
+		goto insanity;
 
 	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
 	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
@@ -199,7 +202,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	msblk->read_page = squashfs_cache_init("data",
 		squashfs_max_decompressors(), msblk->block_size);
 	if (msblk->read_page == NULL) {
-		ERROR("Failed to allocate read_page block\n");
+		errorf(fc, "Failed to allocate read_page block");
 		goto failed_mount;
 	}
 
@@ -207,7 +210,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (IS_ERR(msblk->stream)) {
 		err = PTR_ERR(msblk->stream);
 		msblk->stream = NULL;
-		goto failed_mount;
+		goto insanity;
 	}
 
 	/* Handle xattrs */
@@ -222,7 +225,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
 		xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
 	if (IS_ERR(msblk->xattr_id_table)) {
-		ERROR("unable to read xattr id index table\n");
+		errorf(fc, "unable to read xattr id index table");
 		err = PTR_ERR(msblk->xattr_id_table);
 		msblk->xattr_id_table = NULL;
 		if (err != -ENOTSUPP)
@@ -236,7 +239,7 @@ allocate_id_index_table:
 		le64_to_cpu(sblk->id_table_start), next_table,
 		le16_to_cpu(sblk->no_ids));
 	if (IS_ERR(msblk->id_table)) {
-		ERROR("unable to read id index table\n");
+		errorf(fc, "unable to read id index table");
 		err = PTR_ERR(msblk->id_table);
 		msblk->id_table = NULL;
 		goto failed_mount;
@@ -252,7 +255,7 @@ allocate_id_index_table:
 	msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
 		lookup_table_start, next_table, msblk->inodes);
 	if (IS_ERR(msblk->inode_lookup_table)) {
-		ERROR("unable to read inode lookup table\n");
+		errorf(fc, "unable to read inode lookup table");
 		err = PTR_ERR(msblk->inode_lookup_table);
 		msblk->inode_lookup_table = NULL;
 		goto failed_mount;
@@ -277,7 +280,7 @@ handle_fragments:
 	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
 		le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
 	if (IS_ERR(msblk->fragment_index)) {
-		ERROR("unable to read fragment index table\n");
+		errorf(fc, "unable to read fragment index table");
 		err = PTR_ERR(msblk->fragment_index);
 		msblk->fragment_index = NULL;
 		goto failed_mount;
@@ -288,13 +291,13 @@ check_directory_table:
 	/* Sanity check directory_table */
 	if (msblk->directory_table > next_table) {
 		err = -EINVAL;
-		goto failed_mount;
+		goto insanity;
 	}
 
 	/* Sanity check inode_table */
 	if (msblk->inode_table >= msblk->directory_table) {
 		err = -EINVAL;
-		goto failed_mount;
+		goto insanity;
 	}
 
 	/* allocate root */
@@ -323,6 +326,8 @@ check_directory_table:
 	kfree(sblk);
 	return 0;
 
+insanity:
+	errorf(fc, "squashfs image failed sanity check");
 failed_mount:
 	squashfs_cache_delete(msblk->block_cache);
 	squashfs_cache_delete(msblk->fragment_cache);
@@ -338,6 +343,28 @@ failed_mount:
 	return err;
 }
 
+static int squashfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, squashfs_fill_super);
+}
+
+static int squashfs_reconfigure(struct fs_context *fc)
+{
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_RDONLY;
+	return 0;
+}
+
+static const struct fs_context_operations squashfs_context_ops = {
+	.get_tree	= squashfs_get_tree,
+	.reconfigure	= squashfs_reconfigure,
+};
+
+static int squashfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &squashfs_context_ops;
+	return 0;
+}
 
 static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
@@ -360,14 +387,6 @@ static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 }
 
 
-static int squashfs_remount(struct super_block *sb, int *flags, char *data)
-{
-	sync_filesystem(sb);
-	*flags |= SB_RDONLY;
-	return 0;
-}
-
-
 static void squashfs_put_super(struct super_block *sb)
 {
 	if (sb->s_fs_info) {
@@ -386,14 +405,6 @@ static void squashfs_put_super(struct super_block *sb)
 	}
 }
 
-
-static struct dentry *squashfs_mount(struct file_system_type *fs_type,
-				int flags, const char *dev_name, void *data)
-{
-	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
-}
-
-
 static struct kmem_cache *squashfs_inode_cachep;
 
 
@@ -470,7 +481,7 @@ static void squashfs_free_inode(struct inode *inode)
 static struct file_system_type squashfs_fs_type = {
 	.owner = THIS_MODULE,
 	.name = "squashfs",
-	.mount = squashfs_mount,
+	.init_fs_context = squashfs_init_fs_context,
 	.kill_sb = kill_block_super,
 	.fs_flags = FS_REQUIRES_DEV
 };
@@ -481,7 +492,6 @@ static const struct super_operations squashfs_super_ops = {
 	.free_inode = squashfs_free_inode,
 	.statfs = squashfs_statfs,
 	.put_super = squashfs_put_super,
-	.remount_fs = squashfs_remount
 };
 
 module_init(init_squashfs_fs);
diff --git a/fs/super.c b/fs/super.c
index 2d679db9e8c7..8020974b2a68 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1164,9 +1164,11 @@ int vfs_get_super(struct fs_context *fc,
 {
 	int (*test)(struct super_block *, struct fs_context *);
 	struct super_block *sb;
+	int err;
 
 	switch (keying) {
 	case vfs_get_single_super:
+	case vfs_get_single_reconf_super:
 		test = test_single_super;
 		break;
 	case vfs_get_keyed_super:
@@ -1184,18 +1186,29 @@ int vfs_get_super(struct fs_context *fc,
 		return PTR_ERR(sb);
 
 	if (!sb->s_root) {
-		int err = fill_super(sb, fc);
-		if (err) {
-			deactivate_locked_super(sb);
-			return err;
-		}
+		err = fill_super(sb, fc);
+		if (err)
+			goto error;
 
 		sb->s_flags |= SB_ACTIVE;
+		fc->root = dget(sb->s_root);
+	} else {
+		fc->root = dget(sb->s_root);
+		if (keying == vfs_get_single_reconf_super) {
+			err = reconfigure_super(fc);
+			if (err < 0) {
+				dput(fc->root);
+				fc->root = NULL;
+				goto error;
+			}
+		}
 	}
 
-	BUG_ON(fc->root);
-	fc->root = dget(sb->s_root);
 	return 0;
+
+error:
+	deactivate_locked_super(sb);
+	return err;
 }
 EXPORT_SYMBOL(vfs_get_super);
 
@@ -1215,6 +1228,14 @@ int get_tree_single(struct fs_context *fc,
 }
 EXPORT_SYMBOL(get_tree_single);
 
+int get_tree_single_reconf(struct fs_context *fc,
+		  int (*fill_super)(struct super_block *sb,
+				    struct fs_context *fc))
+{
+	return vfs_get_super(fc, vfs_get_single_reconf_super, fill_super);
+}
+EXPORT_SYMBOL(get_tree_single_reconf);
+
 int get_tree_keyed(struct fs_context *fc,
 		  int (*fill_super)(struct super_block *sb,
 				    struct fs_context *fc),