Carsten Otte 0e4a9b5928 ext2/xip: refuse to change xip flag during remount with busy inodes ... For a reason that I was unable to understand in three months of debugging, mount ext2 -o remount stopped working properly when remounting from regular operation to xip, or the other way around. According to a git bisect search, the problem was introduced with the VM_MIXEDMAP/PTE_SPECIAL rework in the vm: commit 70688e4dd1 Author: Nick Piggin <npiggin@suse.de> Date: Mon Apr 28 02:13:02 2008 -0700 xip: support non-struct page backed memory In the failing scenario, the filesystem is mounted read only via root= kernel parameter on s390x. During remount (in rc.sysinit), the inodes of the bash binary and its libraries are busy and cannot be invalidated (the bash which is running rc.sysinit resides on subject filesystem). Afterwards, another bash process (running ifup-eth) recurses into a subshell, runs dup_mm (via fork). Some of the mappings in this bash process were created from inodes that could not be invalidated during remount. Both parent and child process crash some time later due to inconsistencies in their address spaces. The issue seems to be timing sensitive, various attempts to recreate it have failed. This patch refuses to change the xip flag during remount in case some inodes cannot be invalidated. This patch keeps users from running into that issue. [akpm@linux-foundation.org: cleanup] Signed-off-by: Carsten Otte <cotte@de.ibm.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2009-02-11 14:25:36 -08:00
..
acl.c	[PATCH] sanitize ->permission() prototype	2008-07-26 20:53:14 -04:00
acl.h	[PATCH] sanitize ->permission() prototype	2008-07-26 20:53:14 -04:00
balloc.c	CRED: Wrap task credential accesses in the Ext2 filesystem	2008-11-14 10:38:50 +11:00
dir.c	ext2: also update the inode on disk when dir is IS_DIRSYNC	2009-01-15 16:39:42 -08:00
ext2.h	[PATCH] get rid of on-stack dentry in ext2_get_parent()	2008-10-23 05:13:09 -04:00
file.c	generic block based fiemap implementation	2008-10-03 17:32:43 -04:00
fsync.c
ialloc.c	ext2: tighten restrictions on inode flags	2009-01-08 08:31:00 -08:00
inode.c	ext2: fix ext2_splice_branch() comments	2009-01-08 08:31:00 -08:00
ioctl.c	ext2: tighten restrictions on inode flags	2009-01-08 08:31:00 -08:00
Kconfig	fs/Kconfig: move ext2, ext3, ext4, JBD, JBD2 out	2008-10-20 11:43:59 -07:00
Makefile
namei.c	nfsd race fixes: ext2	2008-12-31 18:07:43 -05:00
super.c	ext2/xip: refuse to change xip flag during remount with busy inodes	2009-02-11 14:25:36 -08:00
symlink.c
xattr_security.c
xattr_trusted.c
xattr_user.c
xattr.c
xattr.h
xip.c	[PATCH] move block_device_operations to blkdev.h	2008-10-21 07:47:20 -04:00
xip.h