From ad775f5a8faa5845377f093ca11caf577404add9 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:38:01 -0800 Subject: [PATCH] r/o bind mounts: debugging for missed calls There have been a few oopses caused by 'struct file's with NULL f_vfsmnts. There was also a set of potentially missed mnt_want_write()s from dentry_open() calls. This patch provides a very simple debugging framework to catch these kinds of bugs. It will WARN_ON() them, but should stop us from having any oopses or mnt_writer count imbalances. I'm quite convinced that this is a good thing because it found bugs in the stuff I was working on as soon as I wrote it. [hch: made it conditional on a debug option. But it's still a little bit too ugly] [hch: merged forced remount r/o fix from Dave and akpm's fix for the fix] Signed-off-by: Dave Hansen Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- lib/Kconfig.debug | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib/Kconfig.debug') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 95de3102bc8..623ef24c238 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -427,6 +427,16 @@ config DEBUG_VM If unsure, say N. +config DEBUG_WRITECOUNT + bool "Debug filesystem writers count" + depends on DEBUG_KERNEL + help + Enable this to catch wrong use of the writers count in struct + vfsmount. This will increase the size of each file struct by + 32 bits. + + If unsure, say N. + config DEBUG_LIST bool "Debug linked list manipulation" depends on DEBUG_KERNEL -- cgit v1.2.3