linux_dsm_epyc7002/fs/nilfs2
Vyacheslav Dubeyko 8c26c4e269 nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption
The NILFS2 driver remounts itself in RO mode in the case of discovering
metadata corruption (for example, discovering a broken bmap).  But
usually, this takes place when there have been file system operations
before remounting in RO mode.

Thereby, NILFS2 driver can be in RO mode with presence of dirty pages in
modified inodes' address spaces.  It results in flush kernel thread's
infinite trying to flush dirty pages in RO mode.  As a result, it is
possible to see such side effects as: (1) flush kernel thread occupies
50% - 99% of CPU time; (2) system can't be shutdowned without manual
power switch off.

SYMPTOMS:
(1) System log contains error message: "Remounting filesystem read-only".
(2) The flush kernel thread occupies 50% - 99% of CPU time.
(3) The system can't be shutdowned without manual power switch off.

REPRODUCTION PATH:
(1) Create volume group with name "unencrypted" by means of vgcreate utility.
(2) Run script (prepared by Anthony Doggett <Anthony2486@interfaces.org.uk>):

  ----------------[BEGIN SCRIPT]--------------------
  #!/bin/bash

  VG=unencrypted
  #apt-get install nilfs-tools darcs
  lvcreate --size 2G --name ntest $VG
  mkfs.nilfs2 -b 1024 -B 8192 /dev/mapper/$VG-ntest
  mkdir /var/tmp/n
  mkdir /var/tmp/n/ntest
  mount /dev/mapper/$VG-ntest /var/tmp/n/ntest
  mkdir /var/tmp/n/ntest/thedir
  cd /var/tmp/n/ntest/thedir
  sleep 2
  date
  darcs init
  sleep 2
  dmesg|tail -n 5
  date
  darcs whatsnew || true
  date
  sleep 2
  dmesg|tail -n 5
  ----------------[END SCRIPT]--------------------

(3) Try to shutdown the system.

REPRODUCIBILITY: 100%

FIX:

This patch implements checking mount state of NILFS2 driver in
nilfs_writepage(), nilfs_writepages() and nilfs_mdt_write_page()
methods.  If it is detected the RO mount state then all dirty pages are
simply discarded with warning messages is written in system log.

[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Anthony Doggett <Anthony2486@interfaces.org.uk>
Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp>
Cc: Piotr Szymaniak <szarpaj@grubelek.pl>
Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com>
Cc: Elmer Zhang <freeboy6716@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 17:04:04 -07:00
..
alloc.c nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty 2011-05-10 22:21:57 +09:00
alloc.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
bmap.c nilfs2: get rid of NILFS_I_NILFS 2011-05-10 22:21:56 +09:00
bmap.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
btnode.c nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty 2011-05-10 22:21:57 +09:00
btnode.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
btree.c nilfs2: fix missing block address termination in btree node shrinking 2011-06-11 15:51:15 +09:00
btree.h
cpfile.c nilfs2: fix timing issue between rmcp and chcp ioctls 2012-07-30 17:25:19 -07:00
cpfile.h nilfs2: use iget for all metadata files 2010-10-23 09:24:38 +09:00
dat.c nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
dat.h nilfs2: use iget for all metadata files 2010-10-23 09:24:38 +09:00
dir.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
direct.c nilfs2: record used amount of each checkpoint in checkpoint list 2011-03-08 14:58:31 +09:00
direct.h
export.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
gcinode.c nilfs2: ensure proper cache clearing for gc-inodes 2012-06-20 14:39:35 -07:00
ifile.c nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
ifile.h nilfs2: use iget for all metadata files 2010-10-23 09:24:38 +09:00
inode.c nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
ioctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
Kconfig fs/nilfs2: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:04 -08:00
Makefile nilfs2: get rid of GCDAT inode 2010-10-23 09:24:38 +09:00
mdt.c nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
mdt.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
namei.c fs: encode_fh: return FILEID_INVALID if invalid fid_type 2013-02-26 02:46:10 -05:00
nilfs.h nilfs2: drop vmtruncate 2012-12-20 18:40:54 -05:00
page.c nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
page.h nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
recovery.c nilfs2: drop vmtruncate 2012-12-20 18:40:54 -05:00
segbuf.c nilfs2: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:24 +08:00
segbuf.h
segment.c nilfs2: Convert to new freezing mechanism 2012-07-31 09:45:52 +04:00
segment.h nilfs2: get rid of private page allocator 2011-05-10 22:21:44 +09:00
sufile.c nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
sufile.h nilfs2: get rid of NILFS_I_NILFS 2011-05-10 22:21:56 +09:00
super.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
the_nilfs.c nilfs2: fix deadlock issue between chcp and thaw ioctls 2012-07-30 17:25:19 -07:00
the_nilfs.h nilfs2: nuke write_super from comments 2012-08-04 12:15:38 +04:00