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authorDave Hansen <haveblue@us.ibm.com>2008-02-16 01:38:01 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-19 08:29:28 +0400
commitad775f5a8faa5845377f093ca11caf577404add9 (patch)
treef124ff1038672b8d2ef004d75c844f740d8fe52b /lib
parent2e4b7fcd926006531935a4c79a5e9349fe51125b (diff)
downloadlinux-ad775f5a8faa5845377f093ca11caf577404add9.tar.xz
[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 <haveblue@us.ibm.com> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug10
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 95de3102bc87..623ef24c2381 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