ceph: drop support for preferred_osd pgs

This was an ill-conceived feature that has been removed from Ceph.  Do
this gracefully:

 - reject attempts to specify a preferred_osd via the ioctl
 - stop exposing this information via virtual xattrs
 - always fill in -1 for requests, in case we talk to an older server
 - don't calculate preferred_osd placements/pgids

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
ceph: refactor SETLAYOUT and SETDIRLAYOUT ioctl checks into common helper

Both of these methods perform similar checks; move that code to a helper
so that we can ensure the checks are consistent.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: clean up types, const-ness

Move various types from int -> __u32 (or similar), and add const as
appropriate.

This reflects changes that have been present in the userland implementation
for some time.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: adjust local retry threshold

This small adjustment reflects a change that was made in ceph.git commit
af6a9f30696c900a2a8bd7ae24e8ed15fb4964bb, about 6 months ago.  An N-1
search is not exhaustive.  Fixed ceph.git bug #1594.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: be more tolerant of nonsensical crush maps

If we get a map that doesn't make sense, error out or ignore the badness
instead of BUGging out.  This reflects the ceph.git commits
9895f0bff7dc68e9b49b572613d242315fb11b6c and
8ded26472058d5205803f244c2f33cb6cb10de79.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: use a temporary variable to simplify crush_do_rule

Use a temporary variable here to avoid repeated array lookups and clean up
the code a bit.

This reflects ceph.git commit 6b5be27634ad307b471a5bf0db85c4f5c834885f.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: remove forcefeed functionality

Remove forcefeed functionality from CRUSH.  This is an ugly misfeature that
is mostly useless and unused.  Remove it.

Reflects ceph.git commit ed974b5000f2851207d860a651809af4a1867942.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>

Conflicts:

	net/ceph/crush/mapper.c
crush: remove parent maps

These were used for the ill-fated forcefeed feature.  Remove them.

Reflects ceph.git commit ebdf80edfecfbd5a842b71fbe5732857994380c1.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: fix tree node weight lookup

Fix the node weight lookup for tree buckets by using a correct accessor.

Reflects ceph.git commit d287ade5bcbdca82a3aef145b92924cf1e856733.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: fix memory leak when destroying tree buckets

Reflects ceph.git commit 46d63d98434b3bc9dad2fc9ab23cbaedc3bcb0e4.

Reported-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>
crush: warn on do_rule failure

If we get an error code from crush_do_rule(), print an error to the
console.

Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Sage Weil <sage@inktank.com>