Ceph

commit 188f3ea6867eeb6e950f6efed18d53ff17522bbc
Author: David Zafman <david.zafman@inktank.com>
Date: Mon Feb 11 12:20:23 2013 -0800

osd/PG: store pg_info_t in leveldb (omap), purged_snaps separately

Separate the purged_snaps portion of pg_info_t (the one that gets big).

Feature #3891: osd: move purged_snaps out of info

Add a separate dirty_big_info flag so that we only update the pginfo
    "biginfo" file if that state changes.  This lets us avoid the cost in the
    general case, like a regular PG write.

Add LEVELDBINFO feature

Put info, biginfo in leveldb
    Move epoch to omap

Feature #3892: osd: move pg info into leveldb

Signed-off-by: Sage Weil <sage@inktank.com>
    Signed-off-by: David Zafman <david.zafman@inktank.com>
    Reviewed-by: Sage Weil <sage@inktank.com>
    Reviewed-by: Sam Just <sam.just@inktank.com>