[PATCH 01/17] uml: make 64-bit COW files compatible with 32-bit ones.

From: "Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it>
To: Andrew Morton <akpm@osdl.org>
Cc: Jeff Dike <jdike@addtoit.com>,
	linux-kernel@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net
Subject: [PATCH 01/17] uml: make 64-bit COW files compatible with 32-bit ones.
Date: Fri, 07 Apr 2006 16:30:48 +0200	[thread overview]
Message-ID: <20060407143048.19201.78081.stgit@zion.home.lan> (raw)
In-Reply-To: <20060407142709.19201.99196.stgit@zion.home.lan>

From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

This is the minimal fix to make 64-bit UML binaries create 32-bit
compatible COW files and read them.
I've indeed tested that current code doesn't do this - the code gets SIGFPE for
a division by a value read at the wrong place, where 0 is found.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 arch/um/drivers/cow_user.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index 61951b7..afdf1ea 100644
--- a/arch/um/drivers/cow_user.c
+++ b/arch/um/drivers/cow_user.c
@@ -75,7 +75,7 @@ struct cow_header_v3 {
 	__u32 alignment;
 	__u32 cow_format;
 	char backing_file[PATH_LEN_V3];
-};
+} __attribute__((packed));
 
 /* COW format definitions - for now, we have only the usual COW bitmap */
 #define COW_BITMAP 0
