xfs: clean up the initial read logic in xfs_readsb

The initial sb read is always for a device logical block size buffer.
The device logical block size is provided in the bt_logical_sectorsize in
struct buftarg, so use that instead of the confusingly named
xfs_getsize_buftarg buffer that reads it from the bdev.

Update the comments surrounding the code to better describe what is going
on.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Carlos Maiolino <[email protected]>

0 files changed, 0 insertions, 0 deletions