lp:~gpiccoli/+git/linux

Author: Guilherme G. Piccoli
Author Date: 2018-08-01 12:43:00 UTC

md/raid0: Introduce emergency stop for raid0 arrays

Currently the raid0 driver is not provided with any health checking
mechanism to verify its members are fine. So, if suddenly a member
is removed, for example, a STOP_ARRAY ioctl will be triggered from
userspace, i.e., all the logic for stopping an array relies in the
userspace tools, like mdadm/udev. Particularly, if a raid0 array is
mounted, this stop procedure will fail, since mdadm tries to open
the md block device with O_EXCL flag, which isn't allowed if md is
mounted.

That leads to the following situation: if a raid0 array member is
removed and the array is mounted, some user writing to this array
won't realize errors are happening unless they check kernel log.
In other words, no -EIO is returned and writes (except direct I/Os)
appear normal. Meaning this user might think the wrote data is stored
in the array, but instead garbage was written since raid0 does stripping
and require all members to be working in order not corrupt data.

This patch propose a change in this behavior: to emergency stop a
raid0 array in case one of its members are gone. The check happens
when I/O is queued to raid0 driver, so the driver will confirm if
the block device it plans to read/write has its queue healthy; in
case it's not fine (like a dying or dead queue), raid0 driver will
invoke an emergency removal routine that will mark the md device as
broken and trigger a delayed stop procedure. Also, raid0 will start
refusing new BIOs from this point, returning -EIO.
The emergency stop routine will mark the md request queue as dying
too, as a "flag" to indicate failure in case of a nested raid0 array
configuration (a raid0 composed of raid0 devices).

The delayed stop procedure then will perform the basic stop of the
md device, and will take care in case it holds mounted filesystems,
allowing the stop of a mounted raid0 array - which is common in
other regular block devices like NVMe and SCSI.

This emergency stop mechanism only affects raid0 arrays.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>

Author: Linus Torvalds
Author Date: 2018-07-10 00:16:11 UTC

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid

Pull HID fixes from Jiri Kosina:

 - spectrev1 pattern fix in hiddev from Gustavo A. R. Silva

 - bounds check fix for hid-debug from Daniel Rosenberg

 - regression fix for HID autobinding from Benjamin Tissoires

 - removal of excessive logging from i2c-hid driver from Jason Andryuk

 - fix specific to 2nd generation of Wacom Intuos devices from Jason
   Gerecke

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: hiddev: fix potential Spectre v1
  HID: i2c-hid: Fix "incomplete report" noise
  HID: wacom: Correct touch maximum XY of 2nd-gen Intuos
  HID: debug: check length before copy_to_user()
  HID: core: allow concurrent registration of drivers