Fix global (DB_PRIVATE) lock code: fix recursion counter, retry
failed lock operations for up to 3 minutes.

--- ./lib/backend/db3.c.orig	2017-01-19 14:59:01.432807649 +0000
+++ ./lib/backend/db3.c	2017-01-19 15:13:18.034716068 +0000
@@ -33,6 +33,8 @@ struct dbiCursor_s {
 static struct dbiConfig_s staticdbicfg;
 static struct dbConfig_s staticcfg;
 
+static int _lockdbfd = 0;
+
 /** \ingroup dbi
  */
 static const struct poptOption rdbOptions[] = {
@@ -744,6 +746,8 @@ static int db3_dbiClose(dbiIndex dbi, un
 
 	rpmlog(RPMLOG_DEBUG, "closed   db index       %s/%s\n",
 		dbhome, dbi->dbi_file);
+	if (dbi->cfg.dbi_lockdbfd && !(dbi->dbi_flags & DBI_VERIFYONLY) && _lockdbfd)
+	    _lockdbfd--;
     }
 
     db_fini(rdb, dbhome ? dbhome : "");
@@ -783,6 +787,7 @@ static int dbiFlock(dbiIndex dbi, int mo
 	rc = 1;
     } else {
 	const char *dbhome = rpmdbHome(dbi->dbi_rpmdb);
+	int tries;
 	struct flock l;
 	memset(&l, 0, sizeof(l));
 	l.l_whence = 0;
@@ -792,20 +797,38 @@ static int dbiFlock(dbiIndex dbi, int mo
 		    ? F_RDLCK : F_WRLCK;
 	l.l_pid = 0;
 
-	rc = fcntl(fdno, F_SETLK, (void *) &l);
-	if (rc) {
-	    uint32_t eflags = db_envflags(db);
-	    /* Warning iff using non-private CDB locking. */
-	    rc = (((eflags & DB_INIT_CDB) && !(eflags & DB_PRIVATE)) ? 0 : 1);
-	    rpmlog( (rc ? RPMLOG_ERR : RPMLOG_WARNING),
-		    _("cannot get %s lock on %s/%s\n"),
-		    ((mode & O_ACCMODE) == O_RDONLY)
-			    ? _("shared") : _("exclusive"),
-		    dbhome, dbi->dbi_file);
-	} else {
-	    rpmlog(RPMLOG_DEBUG,
-		    "locked   db index       %s/%s\n",
-		    dbhome, dbi->dbi_file);
+	for (tries = 0; ; tries++) {
+	    rc = fcntl(fdno, F_SETLK, (void *) &l);
+	    if (rc) {
+		uint32_t eflags = db_envflags(db);
+		/* Warning iff using non-private CDB locking. */
+		rc = (((eflags & DB_INIT_CDB) && !(eflags & DB_PRIVATE)) ? 0 : 1);
+		if (errno == EAGAIN && rc) {
+		    struct timespec ts;
+		    if (tries == 0)
+			rpmlog(RPMLOG_WARNING,
+				_("waiting for %s lock on %s/%s\n"),
+				((mode & O_ACCMODE) == O_RDONLY)
+					? _("shared") : _("exclusive"),
+				dbhome, dbi->dbi_file);
+		    ts.tv_sec = (time_t)0;
+		    ts.tv_nsec = 100000000;	/* .1 seconds */
+		    if (tries < 10*60*3) {	/* 3 minutes */
+			nanosleep(&ts, (struct timespec *)0);
+			continue;
+		    }
+		}
+		rpmlog( (rc ? RPMLOG_ERR : RPMLOG_WARNING),
+			_("cannot get %s lock on %s/%s\n"),
+			((mode & O_ACCMODE) == O_RDONLY)
+				? _("shared") : _("exclusive"),
+			dbhome, dbi->dbi_file);
+	    } else {
+		rpmlog(RPMLOG_DEBUG,
+			"locked   db index       %s/%s\n",
+			dbhome, dbi->dbi_file);
+	    }
+	    break;
 	}
     }
     return rc;
@@ -822,7 +845,6 @@ static int db3_dbiOpen(rpmdb rdb, rpmDbi
     DB * db = NULL;
     DBTYPE dbtype = DB_UNKNOWN;
     uint32_t oflags;
-    static int _lockdbfd = 0;
 
     if (dbip)
 	*dbip = NULL;
@@ -902,6 +924,8 @@ static int db3_dbiOpen(rpmdb rdb, rpmDbi
 	dbi->dbi_flags |= DBI_CREATED;
     if (oflags & DB_RDONLY)
 	dbi->dbi_flags |= DBI_RDONLY;
+    if (verifyonly)
+	dbi->dbi_flags |= DBI_VERIFYONLY;
 
     if (!verifyonly && rc == 0 && dbi->cfg.dbi_lockdbfd && _lockdbfd++ == 0) {
 	rc = dbiFlock(dbi, rdb->db_mode);
--- ./lib/backend/dbi.h.orig	2017-01-19 15:12:26.833899257 +0000
+++ ./lib/backend/dbi.h	2017-01-19 15:05:43.958347554 +0000
@@ -83,6 +83,7 @@ enum dbiFlags_e {
     DBI_NONE		= 0,
     DBI_CREATED		= (1 << 0),
     DBI_RDONLY		= (1 << 1),
+    DBI_VERIFYONLY	= (1 << 2),
 };
 
 enum dbcFlags_e {