[PATCH 4.9 011/102] partitions/msdos: Unable to mount UFS 44bsd partitions

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Richard Narron <comet.berkeley@gmail.com>

commit 5f15684bd5e5ef39d4337988864fec8012471dda upstream.

UFS partitions from newer versions of FreeBSD 10 and 11 use relative
addressing for their subpartitions. But older versions of FreeBSD still
use absolute addressing just like OpenBSD and NetBSD.

Instead of simply testing for a FreeBSD partition, the code needs to
also test if the starting offset of the C subpartition is zero.

https://bugzilla.kernel.org/show_bug.cgi?id=197733

Signed-off-by: Richard Narron <comet.berkeley@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 block/partitions/msdos.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/block/partitions/msdos.c
+++ b/block/partitions/msdos.c
@@ -300,7 +300,9 @@ static void parse_bsd(struct parsed_part
 			continue;
 		bsd_start = le32_to_cpu(p->p_offset);
 		bsd_size = le32_to_cpu(p->p_size);
-		if (memcmp(flavour, "bsd\0", 4) == 0)
+		/* FreeBSD has relative offset if C partition offset is zero */
+		if (memcmp(flavour, "bsd\0", 4) == 0 &&
+		    le32_to_cpu(l->d_partitions[2].p_offset) == 0)
 			bsd_start += offset;
 		if (offset == bsd_start && size == bsd_size)
 			/* full parent partition, we have it already */