Re: hfsplus mount regression in 2.6.38

From: Christoph Hellwig
Date: Fri May 27 2011 - 05:46:40 EST


On Wed, May 25, 2011 at 09:25:21AM -0500, Seth Forshee wrote:
> Reverting commits 52399b1 (hfsplus: use raw bio access for the volume
> headers) and 358f26d5 (hfsplus: use raw bio access for partition tables)
> fixes the problems. It appears the problems are due to hfsplus
> submitting 512 byte bios to a block device whose sector size is larger
> than 512 byts (2 KB in the log above), and the block driver is quite
> reasonably rejecting any requests without proper sector alignment.
>
> How would you suggest fixing this? Most file systems are using
> sb_bread() for this sort of thing, but since the offending patches are
> intended to stop using buffer_heads I'm assuming that's not an option.

Basically all hardcoded uses of HFSPLUS_SECTOR_SIZE need to be replaced
with a use of bdev_logical_block_size, or a per-sb variable derived from
it, and the addressing needs to be accomodated to fit it. I'd need to
look into a bit more detail in what form the sectors we pass into it
are in - we might have to convert them from 512byte to large units,
or they might already be in it. If they happen to be in 512 byte units
we might have to do read-modify write cycles.

What large sector size device do you have, a CDROM?
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