tree 4f2d9dc0f9070ce829d03097542e7968e02df41a
parent 97178b7b6c84bd14660b89474d27931a1ea65c66
author bharrosh@panasas.com <bharrosh@panasas.com> 1286476098 -0400
committer Boaz Harrosh <bharrosh@panasas.com> 1300194170 +0200

exofs: Override read-ahead to align on stripe_size

* Set all inode->i_mapping->backing_dev_info to point to
  the per super-block sb->s_bdi.

* Calculating a read_ahead that is:
  - preferable 2 stripes long
    (Future patch will add a mount option to override this)
  - Minimum 128K aligned up to stripe-size
  - Caped to maximum-IO-sizes round down to stripe_size.
    (Max sizes are governed by max bio-size that fits in a page
     times number-of-devices)

CC: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>