[PATCH] fix UFS superblock alignment issues

From: Eric Sandeen
Date: Mon Oct 30 2006 - 22:46:55 EST


ufs2 fails to mount on x86_64, claiming bad magic. This is because ufs_super_block_third's fs_un1 member is padded out by 4 bytes for
8-byte alignment, pushing down the rest of the struct.

Forcing this to be packed solves it. I took a quick look over
other on-disk structures and didn't immediately find other problems.
I was able to mount & ls a populated ufs2 filesystem w/ this change.

Thanks,
-Eric

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>

Index: linux-2.6.18/include/linux/ufs_fs.h
===================================================================
--- linux-2.6.18.orig/include/linux/ufs_fs.h
+++ linux-2.6.18/include/linux/ufs_fs.h
@@ -900,7 +900,7 @@ struct ufs_super_block_third {
__fs64 fs_csaddr; /* blk addr of cyl grp summary area */
__fs64 fs_pendingblocks;/* blocks in process of being freed */
__fs32 fs_pendinginodes;/*inodes in process of being freed */
- } fs_u2;
+ } __attribute__ ((packed)) fs_u2;
} fs_un1;
union {
struct {


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