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Tomasz Majchrzak d82dd0e34d raid1: prefer disk without bad blocks
If an array consists of two drives and the first drive has the bad
block, the read request to the region overlapping the bad block chooses
the same disk (with bad block) as device to read from over and over and
the request gets stuck. If the first disk only partially overlaps with
bad block, it becomes a candidate ("best disk") for shorter range of
sectors. The second disk is capable of reading the entire requested
range and it is updated accordingly, however it is not recorded as a
best device for the request. In the end the request is sent to the first
disk to read entire range of sectors. It fails and is re-tried in a
moment but with the same outcome.

Actually it is quite likely scenario but it had little exposure in my
test until commit 715d40b93b10 ("md/raid1: add failfast handling for
reads.") removed preference for idle disk. Such scenario had been
passing as second disk was always chosen when idle.

Reset a candidate ("best disk") to read from if disk can read entire
range. Do it only if other disk has already been chosen as a candidate
for a smaller range. The head position / disk type logic will select
the best disk to read from - it is fine as disk with bad block won't be
considered for it.

Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2017-05-12 14:41:15 -07:00
arch platform-drivers-x86 for v4.12-1 2017-05-04 11:56:59 -07:00
block Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-05-03 10:05:38 -07:00
certs KEYS: Use structure to capture key restriction function and data 2017-04-04 14:10:10 -07:00
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
Documentation SCSI misc on 20170503 2017-05-04 12:19:44 -07:00
drivers raid1: prefer disk without bad blocks 2017-05-12 14:41:15 -07:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Merge branch 'akpm' (patches from Andrew) 2017-05-03 17:55:59 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-04 12:26:43 -07:00
init New features for this release: 2017-05-03 18:41:21 -07:00
ipc kernel-api.rst: fix a series of errors when parsing C files 2017-04-02 14:31:49 -06:00
kernel Modules updates for v4.12 2017-05-03 19:12:27 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-04 12:26:43 -07:00
mm New features for this release: 2017-05-03 18:41:21 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-04 12:26:43 -07:00
samples samples/bpf: export map_data[] for more info on maps 2017-05-03 09:30:24 -04:00
scripts Modules updates for v4.12 2017-05-03 19:12:27 -07:00
security Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
sound sound updates for 4.12-rc1 2017-05-03 11:58:59 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-04 12:26:43 -07:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-04 12:26:43 -07:00
Makefile A reasonably busy cycle for documentation this time around. There is a new 2017-05-02 10:21:17 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.