From: Eric Sandeen 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. Signed-off-by: Eric Sandeen Cc: Evgeniy Dushistov Signed-off-by: Andrew Morton --- include/linux/ufs_fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN include/linux/ufs_fs.h~fix-ufs-superblock-alignment-issues include/linux/ufs_fs.h --- a/include/linux/ufs_fs.h~fix-ufs-superblock-alignment-issues +++ a/include/linux/ufs_fs.h @@ -908,7 +908,7 @@ 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 { _