commit 890883f12e8d8dd3309743eb95cf0b04f6e39ea0
Author: Aki Tuomi <aki.tuomi@dovecot.fi>
Date:   Mon Mar 19 18:39:27 2018 +0200

    dsync: Revert to /tmp if home does not exist
    
    Fixes doveadm: Error: Couldn't lock .dovecot-sync.lock: safe_mkstemp(.dovecot-sync.lock) failed: No such file or directory

diff --git a/src/doveadm/dsync/dsync-brain.c b/src/doveadm/dsync/dsync-brain.c
index c2b8169..1e84182 100644
--- a/src/doveadm/dsync/dsync-brain.c
+++ b/src/doveadm/dsync/dsync-brain.c
@@ -401,6 +401,7 @@ dsync_brain_lock(struct dsync_brain *brain, const char *remote_hostname)
                .lock_method = FILE_LOCK_METHOD_FCNTL,
        };
        const char *home, *error, *local_hostname = my_hostdomain();
+       struct stat st;
        bool created;
        int ret;
 
@@ -437,8 +438,21 @@ dsync_brain_lock(struct dsync_brain *brain, const char *remote_hostname)
 
        if (brain->verbose_proctitle)
                process_title_set(dsync_brain_get_proctitle_full(brain, DSYNC_BRAIN_TITLE_LOCKING));
-       brain->lock_path = p_strconcat(brain->pool, home,
-                                      "/"DSYNC_LOCK_FILENAME, NULL);
+
+       /* if homedir does not yet exist, create lock under tmpdir */
+       if (stat(home, &st) < 0) {
+               if (errno != ENOENT) {
+                       i_error("stat(%s) failed: %m", home);
+                       return -1;
+               }
+               brain->lock_path = p_strdup_printf(brain->pool, "%s/%s-%s",
+                                                  brain->user->set->mail_temp_dir,
+                                                  brain->user->username,
+                                                  "/"DSYNC_LOCK_FILENAME);
+       } else {
+               brain->lock_path = p_strconcat(brain->pool, home,
+                                              "/"DSYNC_LOCK_FILENAME, NULL);
+       }
        brain->lock_fd = file_create_locked(brain->lock_path, &lock_set,
                                            &brain->lock, &created, &error);
        if (brain->lock_fd == -1)