Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NSage Weil <sage@newdream.net>

If the force argument isn't valid, we should continue calculating a
mapping as if it weren't specified.
Signed-off-by: NSage Weil <sage@newdream.net>

This factors out protocol and low-level storage parts of ceph into a
separate libceph module living in net/ceph and include/linux/ceph.  This
is mostly a matter of moving files around.  However, a few key pieces
of the interface change as well:

 - ceph_client becomes ceph_fs_client and ceph_client, where the latter
   captures the mon and osd clients, and the fs_client gets the mds client
   and file system specific pieces.
 - Mount option parsing and debugfs setup is correspondingly broken into
   two pieces.
 - The mon client gets a generic handler callback for otherwise unknown
   messages (mds map, in this case).
 - The basic supported/required feature bits can be expanded (and are by
   ceph_fs_client).

No functional change, aside from some subtle error handling cases that got
cleaned up in the refactoring process.
Signed-off-by: NSage Weil <sage@newdream.net>

Fix a typo that made any OSD weighted between 0.1 and 1.0 effectively
weighted as 1.0 (fully in).
Signed-off-by: NSage Weil <sage@newdream.net>

We may not recurse for CHOOSE_LEAF if we start with a leaf node.  When
that happens, the out2 vector needs to be filled in with the result.
Signed-off-by: NSage Weil <sage@newdream.net>

There was a longstanding problem with recursion through intervening
bucket types on complex hierarchies.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

Make the integer hash function a property of the bucket it is used on.  This
allows us to gracefully add support for new hash functions without starting
from scatch.
Signed-off-by: NSage Weil <sage@newdream.net>

Even when we encounter a corrupt bucket.  We still BUG().  This fixes
the warning

fs/ceph/crush/mapper.c: In function 'crush_choose':
fs/ceph/crush/mapper.c:352: warning: control may reach end of non-void function
'crush_bucket_choose' being inlined
Signed-off-by: NSage Weil <sage@newdream.net>

This avoids a divide by zero when the input and/or map are
malformed.
Signed-off-by: NSage Weil <sage@newdream.net>

CRUSH is a pseudorandom data distribution function designed to map
inputs onto a dynamic hierarchy of devices, while minimizing the
extent to which inputs are remapped when the devices are added or
removed.  It includes some features that are specifically useful for
storage, most notably the ability to map each input onto a set of N
devices that are separated across administrator-defined failure
domains.  CRUSH is used to distribute data across the cluster of Ceph
storage nodes.

More information about CRUSH can be found in this paper:

    http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdfSigned-off-by: NSage Weil <sage@newdream.net>