vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API

Convert the ramfs, shmem, tmpfs, devtmpfs and rootfs filesystems 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.

Note that tmpfs is slightly tricky as it can contain embedded commas, so it
can't be trivially split up using strsep() to break on commas in
generic_parse_monolithic().  Instead, tmpfs has to supply its own generic
parser.

However, if tmpfs changes, then devtmpfs and rootfs, which are wrappers
around tmpfs or ramfs, must change too - and thus so must ramfs, so these
had to be converted also.

[AV: rewritten]

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hugh Dickins <hughd@google.com>
cc: linux-mm@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 5 deletions

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 16c29e57f224..9634ecf3743d 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -627,18 +627,17 @@ out:
 }
 
 static bool is_tmpfs;
-static struct dentry *rootfs_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int rootfs_init_fs_context(struct fs_context *fc)
 {
 	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
-		return shmem_mount(fs_type, flags, dev_name, data);
+		return shmem_init_fs_context(fc);
 
-	return ramfs_mount(fs_type, flags, dev_name, data);
+	return ramfs_init_fs_context(fc);
 }
 
 struct file_system_type rootfs_fs_type = {
 	.name		= "rootfs",
-	.mount		= rootfs_mount,
+	.init_fs_context = rootfs_init_fs_context,
 	.kill_sb	= kill_litter_super,
 };