[PATCH 00/20] ref transactions part 2

This is the next 20 patches from my originally big patch series and follow the previous 19 patches that is now in juns tree. These patches were numbered 20-39 in the original 48-patch series.

Changes since these patches were in the original series:

- Addressing concerns from mhagger's review

Ronnie Sahlberg (20):
  refs.c: change ref_transaction_create to do error checking and return
    status
  refs.c: update ref_transaction_delete to check for error and return
    status
  refs.c: make ref_transaction_begin take an err argument
  refs.c: add transaction.status and track OPEN/CLOSED/ERROR
  tag.c: use ref transactions when doing updates
  replace.c: use the ref transaction functions for updates
  commit.c: use ref transactions for updates
  sequencer.c: use ref transactions for all ref updates
  fast-import.c: change update_branch to use ref transactions
  branch.c: use ref transaction for all ref updates
  refs.c: change update_ref to use a transaction
  receive-pack.c: use a reference transaction for updating the refs
  fast-import.c: use a ref transaction when dumping tags
  walker.c: use ref transaction for ref updates
  refs.c: make lock_ref_sha1 static
  refs.c: remove the update_ref_lock function
  refs.c: remove the update_ref_write function
  refs.c: remove lock_ref_sha1
  refs.c: make prune_ref use a transaction to delete the ref
  refs.c: make delete_ref use a transaction

 branch.c               |  30 +++---
 builtin/commit.c       |  24 +++--
 builtin/receive-pack.c |  96 +++++++++++++-------
 builtin/replace.c      |  15 +--
 builtin/tag.c          |  15 +--
 builtin/update-ref.c   |  11 ++-
 fast-import.c          |  53 +++++++----
 refs.c                 | 242 ++++++++++++++++++++++++++++---------------------
 refs.h                 |  78 ++++++++++++----
 sequencer.c            |  27 ++++--
 walker.c               |  59 +++++++-----
 11 files changed, 403 insertions(+), 247 deletions(-)