[dovecot/core] 67654c: lib: Make file_lock_free(NULL) no-op

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 67654ca6848cdb83ef96be7a6584695f8a01535d
      https://github.com/dovecot/core/commit/67654ca6848cdb83ef96be7a6584695f8a01535d
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-12-28 (Thu, 28 Dec 2017)

  Changed paths:
    M src/lib/file-lock.c

  Log Message:
  -----------
  lib: Make file_lock_free(NULL) no-op


  Commit: c864fdd520b0c3f10a4b9bc5373368f4ae8faaff
      https://github.com/dovecot/core/commit/c864fdd520b0c3f10a4b9bc5373368f4ae8faaff
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-12-28 (Thu, 28 Dec 2017)

  Changed paths:
    M src/doveadm/dsync/dsync-brain-mailbox.c
    M src/doveadm/dsync/dsync-brain-private.h
    M src/doveadm/dsync/dsync-brain.c
    M src/doveadm/dsync/dsync-mailbox.c
    M src/doveadm/dsync/dsync-mailbox.h

  Log Message:
  -----------
  dsync: Add per-mailbox sync lock that is always used.

Both importing and exporting gets the lock before they even sync the
mailbox. The lock is kept until the import/export finishes. This guarantees
that no matter how dsync is run, two dsyncs can't be working on the same
mailbox at the same time.

This lock is in addition to the optional per-user lock enabled by the -l
parameter. If the -l parameter is used, the same lock timeout is used for
the per-mailbox lock. Otherwise 30s timeout is used.

This should help to avoid email duplication when replication is enabled for
public namespaces, and maybe in some other rare situations as well.


Compare: https://github.com/dovecot/core/compare/e5a90184beb2...c864fdd520b0