[PATCH v3 00/17] Fix some mkdir/rmdir races

Sorry, I forgot to send this re-roll to the mailing list.

This version differs only very slightly from v2:

* Rebased to the current master (there were no conflicts).

* Rename a couple of local variables from "attempts" to
  "attempts_remaining".

* Patches 13, 16, and 17 have slightly improved commit messages.

Michael Haggerty (17):
  safe_create_leading_directories(): fix format of "if" chaining
  safe_create_leading_directories(): reduce scope of local variable
  safe_create_leading_directories(): add explicit "slash" pointer
  safe_create_leading_directories(): rename local variable
  safe_create_leading_directories(): split on first of multiple slashes
  safe_create_leading_directories(): always restore slash at end of loop
  safe_create_leading_directories(): introduce enum for return values
  cmd_init_db(): when creating directories, handle errors conservatively
  safe_create_leading_directories(): add new error value SCLD_VANISHED
  lock_ref_sha1_basic(): on SCLD_VANISHED, retry
  lock_ref_sha1_basic(): if locking fails with ENOENT, retry
  remove_dir_recurse(): tighten condition for removing unreadable dir
  remove_dir_recurse(): handle disappearing files and directories
  rename_ref(): extract function rename_tmp_log()
  rename_tmp_log(): handle a possible mkdir/rmdir race
  rename_tmp_log(): limit the number of remote_empty_directories()
    attempts
  rename_tmp_log(): on SCLD_VANISHED, retry

 builtin/init-db.c |  9 +++---
 cache.h           | 25 +++++++++++++--
 dir.c             | 27 +++++++++++-----
 merge-recursive.c |  2 +-
 refs.c            | 92 ++++++++++++++++++++++++++++++++++++++++---------------
 sha1_file.c       | 67 ++++++++++++++++++++++------------------
 6 files changed, 155 insertions(+), 67 deletions(-)