[PATCH 4/4] fs: Warn about writing !uptodate buffers

[Jan Kara <jack@suse.cz>]

Make submit_bh() warn about writing !uptodate buffers. Hopefully this
warns us about writing garbage (although bugs in write EIO handling
are going to trigger this as well as they already trigger the warning
in mark_buffer_dirty()).

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 22c0144..985f617 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2997,6 +2997,8 @@ int submit_bh(int rw, struct buffer_head * bh)
 	BUG_ON(!buffer_locked(bh));
 	BUG_ON(!buffer_mapped(bh));
 	BUG_ON(!bh->b_end_io);
+	if (rw & WRITE)
+		WARN_ON_ONCE(!buffer_uptodate(bh));
 
 	/*
 	 * Mask in barrier bit for a write (could be either a WRITE or a
-- 
1.6.0.2