[PATCH] uml: make 64-bit COW files compatible with 32-bit ones

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>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index 61951b7..afdf1ea 100644 (file)
--- 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