We were incorrectly calculationing of object offset.  If we have multiple
stripe units per object, we need to shift to the start of the current
su in addition to the offset within the su.

Also rename bno to ono (object number) to avoid some variable naming
confusion.
Signed-off-by: NSage Weil <sage@newdream.net>

The object extent offset is the file offset _modulo_ the stripe unit.
The code was correct, the comment was wrong.
Reported-by: NNoah Watkins <jayhawk@soe.ucsc.edu>
Signed-off-by: NSage Weil <sage@newdream.net>

Using stripe unit size calculated and saved on the stack to avoid
a redundant call to le32_to_cpu.
Signed-off-by: NNoah Watkins <noah@noahdesu.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Mix the preferred osd (if any) into the placement seed that is fed into
the CRUSH object placement calculation.  This prevents all the placement
pgs from peering with the same osds.

Rev the osd client protocol with this change.
Signed-off-by: NSage Weil <sage@newdream.net>

This avoids the fugly pass by reference and makes the code a bit easier
to read.
Signed-off-by: NSage Weil <sage@newdream.net>

Return an error and report a corrupt map instead of crying BUG().
Signed-off-by: NSage Weil <sage@newdream.net>

The OSD client is responsible for reading and writing data from/to the
object storage pool.  This includes determining where objects are
stored in the cluster, and ensuring that requests are retried or
redirected in the event of a node failure or data migration.

If an OSD does not respond before a timeout expires, keepalive
messages are sent across the lossless, ordered communications channel
to ensure that any break in the TCP is discovered.  If the session
does reset, a reconnection is attempted and affected requests are
resent (by the message transport layer).
Signed-off-by: NSage Weil <sage@newdream.net>