init: add an init_dup helper

Add a simple helper to grab a reference to a file and install it at
the next available fd, and switch the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

init: add an init_utimes helper

Add a simple helper to set timestamps with a kernel space file name and
switch the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_stat helper

Add a simple helper to stat with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_mknod helper

Add a simple helper to mknod with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mknod.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_mkdir helper

Add a simple helper to mkdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mkdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_symlink helper

Add a simple helper to symlink with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_symlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_link helper

Add a simple helper to link with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_link.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_eaccess helper

Add a simple helper to check if a file exists based on kernel space file
name and switch the early init code over to it. Note that this
theoretically changes behavior as it always is based on the effective
permissions. But during early init that doesn't make a difference.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_chmod helper

Add a simple helper to chmod with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_chown helper

Add a simple helper to chown with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_chroot helper

Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chroot.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_chdir helper

Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_chdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_rmdir helper

Add a simple helper to rmdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_rmdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_unlink helper

Add a simple helper to unlink with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_unlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_umount helper

Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>

init: add an init_mount helper

Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>