libext2fs: don't swap extent-based journal backup

The f_illitable_flexbg test was failing on ppc, because
e2fsck_move_ext3_journal is doing a direct memcmp of i_block with
s_jnl_blocks, and failing.

This is because we don't swap extent data on read from disk; rather
we do it when we access the extents.  However, ext2fs_swap_super
was swapping s_jnl_blocks unconditionally, so these didn't match.

Looks like we need to treat s_jnl_blocks the same as i_block, and
swap it on access, not on read.  Except for the last i_size bit...

Reviewed-by: Andreas Dilger <adilger@sun.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c
index 42bc01e..9964919 100644 (file)
--- a/lib/ext2fs/swapfs.c
+++ b/lib/ext2fs/swapfs.c
@@ -73,9 +73,19 @@ void ext2fs_swap_super(struct ext2_super_block * sb)
        sb->s_kbytes_written = ext2fs_swab64(sb->s_kbytes_written);
        for (i=0; i < 4; i++)
                sb->s_hash_seed[i] = ext2fs_swab32(sb->s_hash_seed[i]);
+
+       /* if journal backup is for a valid extent-based journal... */
+       if (!ext2fs_extent_header_verify(sb->s_jnl_blocks,
+                                        sizeof(sb->s_jnl_blocks))) {
+               /* ... swap only the journal i_size */
+               sb->s_jnl_blocks[16] = ext2fs_swab32(sb->s_jnl_blocks[16]);
+               /* and the extent data is not swapped on read */
+               return;
+       }
+
+       /* direct/indirect journal: swap it all */
        for (i=0; i < 17; i++)
                sb->s_jnl_blocks[i] = ext2fs_swab32(sb->s_jnl_blocks[i]);
-
 }
 
 void ext2fs_swap_group_desc(struct ext2_group_desc *gdp)