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Date: Mon, 30 Oct 2006 21:46:09 -0600
From: Eric Sandeen <sandeen@redhat.com>
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To: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
CC: Evgeniy Dushistov <dushistov@mail.ru>
Subject: [PATCH] fix UFS superblock alignment issues
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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@redhat.com>

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 {