git: hammer2 - major simplification of algorithms part 1/many

[Matthew Dillon]

commit da6f36f44bb9c76612e31b56cdfe4d787e53d61f
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Wed Jul 30 00:17:29 2014 -0700

    hammer2 - major simplification of algorithms part 1/many
    
    * Huge simplification of in-memory data structures and algorithms.
      Remove delete-duplicate, ownerq (shadow copies), dbq, dbtree, and most of
      the xid lo/hi sequencing.  Remove all the complexities related to
      managing the above elements.  Net removal of ~1500 lines of code or so.
    
    * Blockmap deletions are now handled by the frontend, so the backend doesn't
      need to deal with shadowed deletions.  This is still fairly optimal since
      insertions are still handled by the backend during flushes.  So for quick
      create/delete operations the blockmap is never even initialized which means
      that deletions don't have to remove anything.
    
    * Cleanup buffer cache on file removal / last-close, but allow file delete
      to simply wipe out the inode.  Don't bother iterating its indirect blocks
      or data blocks on-media but use the flush code to get rid of any chains
      still cached.
    
    * Buffer invalidation on permanent chain deletions for modified chains.
    
    * Major items still TODO: flush interlocks and meta-data updates.

Summary of changes:
 sys/vfs/hammer2/TODO              |    3 +-
 sys/vfs/hammer2/hammer2.h         |  253 +++---
 sys/vfs/hammer2/hammer2_chain.c   | 1667 ++++++++++---------------------------
 sys/vfs/hammer2/hammer2_cluster.c |  177 ++--
 sys/vfs/hammer2/hammer2_flush.c   | 1351 ++++++++----------------------
 sys/vfs/hammer2/hammer2_freemap.c |   14 +-
 sys/vfs/hammer2/hammer2_inode.c   |  368 ++++----
 sys/vfs/hammer2/hammer2_ioctl.c   |    2 +-
 sys/vfs/hammer2/hammer2_subr.c    |    6 +-
 sys/vfs/hammer2/hammer2_vfsops.c  |  198 ++---
 sys/vfs/hammer2/hammer2_vnops.c   |   75 +-
 11 files changed, 1270 insertions(+), 2844 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/da6f36f44bb9c76612e31b56cdfe4d787e53d61f


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