Commit 3a054014e8 replaced our modprobe
with busybox's modprobe. Unfortunately, busybox's modprobe appears to be
unable to properly load modules with more than 1 level of dependencies.
The zfs and zpool commands will invoke modprobe if /dev/zvol is missing,
which concealed this problem. However, this caused problems because some
invocations would fail and under certain circumstances, init would be
killed, causing a kernel panic. This issue was made clear by commit
c812c35100771bb527f6b03853fa6d8ef66a48fe, which ensured that the zpool
and zfs commands were not run until the ZFS module was loaded.
busybox modprobe's failure to load module dependencies correctly appears
to occur because busybox modprobe does not wait until until a module is
loaded before loading a module that depends on it, which is a race. It
would be best to correct this race by waiting until the module has
properly loaded, but it is not clear that the race is the only thing
going wrong and developer time is a premium.
We implement a workaround by modifying the busy loop added in the
previous commit to explicit call `modprobe zfs` on each iteration. While
the first few calls fail due to bugs in busybox modprobe, it will
eventually work, after which each call is a noop. This lets us keep
looping until either the loop exit condition that /dev/zvol exist is
reached or the 5 second timeout is reached.
Once the busybox modprobe issue is fixed, this workaround should be safe
to revert.
Signed-off-by: Richard Yao <ryao@gentoo.org>
udev may still be processing rules and this can cause very bad
things. For instance, modules_load may have loaded an usb host
controller driver and we must wait for the udev rules to terminate.
However, this may lead to other race conditions, but we have
observed that adding scandelay=n where n >= 5 actually fixes the
issue of booting off USB under certain scenarios.
"quiet" is already used by the kernel to avoid printing messages on the
console unless they are errors or warnings. Genkernel should do the same
wrt its initramfs initialization code.
This has also the advantage of improving the boot speed.
scandelay=<secs> should be always preferred. Moreover, nowadays
automatically sleeping waiting for USB storage to come up in
the way we were used to do it doesn't work as one expects, because
USB is very common and USB storage devices are very likely to be
present on a system.
Furthermore, the initialization code after setup_slowusb is already
waiting for devices to come up.
Nearly every general documentation including the one in the
kernel tree and the scripts for GRUB2 all expects this flag
to work.
Signed-off-by: Peter Hjalmarsson <xake@rymdraket.net>
If INIT_OPTS='' is not specified before the argument loop, scoping rules
will prevent it from being seen by the switch_root invocation.
Signed-off-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Clean up documentation and functionality of "part" argument to
initramfs. It is meant to imitate the same option to the kernel.
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
We do not support ramdisk, only initramfs nowdays.
So init= is a dead command, and we may as well have it do the same as
it does for dracut and in the Linux kernel documentation.
(Use rdinit to choose the initramfs init file)
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Somewhere in the mists of time we lost part of the multipath patch, so
we were bundling the userspace, but not the kernel modules, or ever
using it.
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Running `mdev -s` will ensure that device nodes are properly initialized.
It does not function as a netlink hotplug daemon. We must run it after
the modules are loaded to ensure that /dev/zfs has been created before
userland programs attempt to use it.
Effective for genkernel's modprobe script or busybox "not small"
modprobe.
Signed-off-by: Dzianis Kahanovich <mahatma@eu.by>
Updated-by: Richard Yao <ryao@cs.stonybrook.edu>
Fabio Erculiani
Richard Yao
Peter Hjalmarsson
Toralf Förster
Robin H. Johnson
Dustin Frisch
Richard Yao
Dzianis Kahanovich
Kenny Cheng
Sebastian Pipping