Commit 41525f56 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

fs: refactor ksys_umount 



Factor out a path_umount 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 a1e6aaa3

fs/namespace.c

+18 −22
Original line number Diff line number Diff line
@@ -1706,36 +1706,19 @@ static inline bool may_mandlock(void) 
}

#endif



/*

 * Now umount can handle mount points as well as block devices.

 * This is important for filesystems which use unnamed block devices.

 *

 * We now support a flag for forced unmount like the other 'big iron'

 * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD

 */



int ksys_umount(char __user *name, int flags)

static int path_umount(struct path *path, int flags)

{

	struct path path;

	struct mount *mnt;

	int retval;

	int lookup_flags = LOOKUP_MOUNTPOINT;



	if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))

		return -EINVAL;



	if (!may_mount())

		return -EPERM;



	if (!(flags & UMOUNT_NOFOLLOW))

		lookup_flags |= LOOKUP_FOLLOW;



	retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);

	if (retval)

		goto out;

	mnt = real_mount(path.mnt);

	mnt = real_mount(path->mnt);

	retval = -EINVAL;

	if (path.dentry != path.mnt->mnt_root)

	if (path->dentry != path->mnt->mnt_root)

		goto dput_and_out;

	if (!check_mnt(mnt))

		goto dput_and_out;
@@ -1748,12 +1731,25 @@ int ksys_umount(char __user *name, int flags) 
	retval = do_umount(mnt, flags);

dput_and_out:

	/* we mustn't call path_put() as that would clear mnt_expiry_mark */

	dput(path.dentry);

	dput(path->dentry);

	mntput_no_expire(mnt);

out:

	return retval;

}



int ksys_umount(char __user *name, int flags)

{

	int lookup_flags = LOOKUP_MOUNTPOINT;

	struct path path;

	int ret;



	if (!(flags & UMOUNT_NOFOLLOW))

		lookup_flags |= LOOKUP_FOLLOW;

	ret = user_path_at(AT_FDCWD, name, lookup_flags, &path);

	if (ret)

		return ret;

	return path_umount(&path, flags);

}



SYSCALL_DEFINE2(umount, char __user *, name, int, flags)

{

	return ksys_umount(name, flags);

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