From: Boaz Harrosh <bharrosh@panasas.com>
Date: Sun, 22 May 2011 16:52:19 +0000 (+0300)
Subject: pnfs-obj: osd raid engine read/write implementation
X-Git-Tag: v3.0-rc1~2^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=04f83450388e87d86b387cf4a27b81eb7e69de7d;p=pandora-kernel.git

pnfs-obj: osd raid engine read/write implementation

With the use of the in-kernel osd library. Implement read/write
of data from/to osd-objects according to information specified
in the objects-layout.

Support for stripping over mirrors with a received stripe_unit.
There are however a few constrains which are not supported:
 1. Stripe Unit must be a multiple of PAGE_SIZE
 2. stripe length (stripe_unit * number_of_stripes) can not be
    bigger then 32bit.

Also support raid-groups and partial-layout. Partial-layout is
when not all the groups are received on the line, addressing
only a partial range of the file.

TODO:
  Only raid0! raid 4/5/6 support will come at later stage

A none supported layout will send IO through the MDS

[Important fallout from the last rebase]
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
[gfp_flags]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
---

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