Index: dbfile.scm
==================================================================
--- dbfile.scm
+++ dbfile.scm
@@ -495,13 +495,20 @@
 		(dbfile:print-err "INFO: forcing journal rollup "busy-file)
 		(dbfile:brute-force-salvage-db fname)))
 	  (dbfile:cautious-open-database fname init-proc (- tries-left 1)))
 	(let* ((db-exists (file-exists? fname))
 	       (result (condition-case
-			   (let* ((db (sqlite3:open-database fname)))
+			   (let* ((nosyncdb *no-sync-db*)
+				  (lockname (conc fname ".lock"))
+				  (db (begin
+					(dbfile:simple-file-lock-and-wait lockname expire-time: 5)
+					(if nosyncdb (db:no-sync-get-lock nosyncdb fname))
+					(sqlite3:open-database fname))))
 			     (if (and init-proc (not db-exists))
 				 (init-proc db))
+			     (if nosyncdb (db:no-sync-del! nosyncdb fname))
+			     (dbfile:simple-file-release-lock lockname)
 			     db)
 			(exn (io-error)
 			     (dbfile:print-err exn "ERROR: i/o error with " fname ". Check permissions, disk space etc. and try again.")
 			     (retry))
 			(exn (corrupt)