[PATCH] r/o bind mounts: debugging for missed calls
authorDave Hansen <haveblue@us.ibm.com>
Fri, 15 Feb 2008 22:38:01 +0000 (14:38 -0800)
committerAl Viro <viro@zeniv.linux.org.uk>
Sat, 19 Apr 2008 04:29:28 +0000 (00:29 -0400)
commitad775f5a8faa5845377f093ca11caf577404add9
treef124ff1038672b8d2ef004d75c844f740d8fe52b
parent2e4b7fcd926006531935a4c79a5e9349fe51125b
[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>
fs/file_table.c
fs/open.c
fs/super.c
include/linux/fs.h
lib/Kconfig.debug