vfs: split off vfsmount-related parts of vfs_kern_mount()

new function: mount_fs().  Does all work done by vfs_kern_mount()
except the allocation and filling of vfsmount; returns root dentry
or ERR_PTR().

vfs_kern_mount() switched to using it and taken to fs/namespace.c,
along with its wrappers.

alloc_vfsmnt()/free_vfsmnt() made static.

functions in namespace.c slightly reordered.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 16 insertions, 80 deletions

diff --git a/fs/super.c b/fs/super.c
index 4bae0ef6110..e8486490826 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -910,29 +910,18 @@ struct dentry *mount_single(struct file_system_type *fs_type,
 }
 EXPORT_SYMBOL(mount_single);
 
-struct vfsmount *
-vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
+struct dentry *
+mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 {
-	struct vfsmount *mnt;
 	struct dentry *root;
+	struct super_block *sb;
 	char *secdata = NULL;
-	int error;
-
-	if (!type)
-		return ERR_PTR(-ENODEV);
-
-	error = -ENOMEM;
-	mnt = alloc_vfsmnt(name);
-	if (!mnt)
-		goto out;
-
-	if (flags & MS_KERNMOUNT)
-		mnt->mnt_flags = MNT_INTERNAL;
+	int error = -ENOMEM;
 
 	if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
 		secdata = alloc_secdata();
 		if (!secdata)
-			goto out_mnt;
+			goto out;
 
 		error = security_sb_copy_data(data, secdata);
 		if (error)
@@ -944,13 +933,12 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
 		error = PTR_ERR(root);
 		goto out_free_secdata;
 	}
-	mnt->mnt_root = root;
-	mnt->mnt_sb = root->d_sb;
-	BUG_ON(!mnt->mnt_sb);
-	WARN_ON(!mnt->mnt_sb->s_bdi);
-	mnt->mnt_sb->s_flags |= MS_BORN;
+	sb = root->d_sb;
+	BUG_ON(!sb);
+	WARN_ON(!sb->s_bdi);
+	sb->s_flags |= MS_BORN;
 
-	error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
+	error = security_sb_kern_mount(sb, flags, secdata);
 	if (error)
 		goto out_sb;
 
@@ -961,27 +949,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
 	 * violate this rule. This warning should be either removed or
 	 * converted to a BUG() in 2.6.34.
 	 */
-	WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
-		"negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
+	WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
+		"negative value (%lld)\n", type->name, sb->s_maxbytes);
 
-	mnt->mnt_mountpoint = mnt->mnt_root;
-	mnt->mnt_parent = mnt;
-	up_write(&mnt->mnt_sb->s_umount);
+	up_write(&sb->s_umount);
 	free_secdata(secdata);
-	return mnt;
+	return root;
 out_sb:
-	dput(mnt->mnt_root);
-	deactivate_locked_super(mnt->mnt_sb);
+	dput(root);
+	deactivate_locked_super(sb);
 out_free_secdata:
 	free_secdata(secdata);
-out_mnt:
-	free_vfsmnt(mnt);
 out:
 	return ERR_PTR(error);
 }
 
-EXPORT_SYMBOL_GPL(vfs_kern_mount);
-
 /**
  * freeze_super - lock the filesystem and force it into a consistent state
  * @sb: the super to lock
@@ -1071,49 +1053,3 @@ out:
 	return 0;
 }
 EXPORT_SYMBOL(thaw_super);
-
-static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
-{
-	int err;
-	const char *subtype = strchr(fstype, '.');
-	if (subtype) {
-		subtype++;
-		err = -EINVAL;
-		if (!subtype[0])
-			goto err;
-	} else
-		subtype = "";
-
-	mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
-	err = -ENOMEM;
-	if (!mnt->mnt_sb->s_subtype)
-		goto err;
-	return mnt;
-
- err:
-	mntput(mnt);
-	return ERR_PTR(err);
-}
-
-struct vfsmount *
-do_kern_mount(const char *fstype, int flags, const char *name, void *data)
-{
-	struct file_system_type *type = get_fs_type(fstype);
-	struct vfsmount *mnt;
-	if (!type)
-		return ERR_PTR(-ENODEV);
-	mnt = vfs_kern_mount(type, flags, name, data);
-	if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
-	    !mnt->mnt_sb->s_subtype)
-		mnt = fs_set_subtype(mnt, fstype);
-	put_filesystem(type);
-	return mnt;
-}
-EXPORT_SYMBOL_GPL(do_kern_mount);
-
-struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
-{
-	return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
-}
-
-EXPORT_SYMBOL_GPL(kern_mount_data);