Commit a1e6aaa3 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

fs: refactor do_mount 



Factor out a path_mount helper that takes a struct path * instead of the
actual file name.  This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 38b08223

fs/namespace.c

+35 −32
Original line number Diff line number Diff line
@@ -3115,12 +3115,11 @@ char *copy_mount_string(const void __user *data) 
 * Therefore, if this magic number is present, it carries no information

 * and must be discarded.

 */

long do_mount(const char *dev_name, const char __user *dir_name,

static int path_mount(const char *dev_name, struct path *path,

		const char *type_page, unsigned long flags, void *data_page)

{

	struct path path;

	unsigned int mnt_flags = 0, sb_flags;

	int retval = 0;

	int ret;



	/* Discard magic */

	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
@@ -3133,19 +3132,13 @@ long do_mount(const char *dev_name, const char __user *dir_name, 
	if (flags & MS_NOUSER)

		return -EINVAL;



	/* ... and get the mountpoint */

	retval = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path);

	if (retval)

		return retval;



	retval = security_sb_mount(dev_name, &path,

				   type_page, flags, data_page);

	if (!retval && !may_mount())

		retval = -EPERM;

	if (!retval && (flags & SB_MANDLOCK) && !may_mandlock())

		retval = -EPERM;

	if (retval)

		goto dput_out;

	ret = security_sb_mount(dev_name, path, type_page, flags, data_page);

	if (ret)

		return ret;

	if (!may_mount())

		return -EPERM;

	if ((flags & SB_MANDLOCK) && !may_mandlock())

		return -EPERM;



	/* Default to relatime unless overriden */

	if (!(flags & MS_NOATIME))
@@ -3172,7 +3165,7 @@ long do_mount(const char *dev_name, const char __user *dir_name, 
	    ((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME |

		       MS_STRICTATIME)) == 0)) {

		mnt_flags &= ~MNT_ATIME_MASK;

		mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK;

		mnt_flags |= path->mnt->mnt_flags & MNT_ATIME_MASK;

	}



	sb_flags = flags & (SB_RDONLY |
@@ -3185,22 +3178,32 @@ long do_mount(const char *dev_name, const char __user *dir_name, 
			    SB_I_VERSION);



	if ((flags & (MS_REMOUNT | MS_BIND)) == (MS_REMOUNT | MS_BIND))

		retval = do_reconfigure_mnt(&path, mnt_flags);

	else if (flags & MS_REMOUNT)

		retval = do_remount(&path, flags, sb_flags, mnt_flags,

		return do_reconfigure_mnt(path, mnt_flags);

	if (flags & MS_REMOUNT)

		return do_remount(path, flags, sb_flags, mnt_flags, data_page);

	if (flags & MS_BIND)

		return do_loopback(path, dev_name, flags & MS_REC);

	if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))

		return do_change_type(path, flags);

	if (flags & MS_MOVE)

		return do_move_mount_old(path, dev_name);



	return do_new_mount(path, type_page, sb_flags, mnt_flags, dev_name,

			    data_page);

	else if (flags & MS_BIND)

		retval = do_loopback(&path, dev_name, flags & MS_REC);

	else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))

		retval = do_change_type(&path, flags);

	else if (flags & MS_MOVE)

		retval = do_move_mount_old(&path, dev_name);

	else

		retval = do_new_mount(&path, type_page, sb_flags, mnt_flags,

				      dev_name, data_page);

dput_out:

}



long do_mount(const char *dev_name, const char __user *dir_name,

		const char *type_page, unsigned long flags, void *data_page)

{

	struct path path;

	int ret;



	ret = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path);

	if (ret)

		return ret;

	ret = path_mount(dev_name, &path, type_page, flags, data_page);

	path_put(&path);

	return retval;

	return ret;

}



static struct ucounts *inc_mnt_namespaces(struct user_namespace *ns)

CRA Git | Maintained and supported by SUSTech CRA and CCSE