- check for stale locks when opening write-cursors (#860500, #962750...)

rpm-4.11.x-cursor-failchk.patch

@@ -0,0 +1,56 @@
+commit 452553111b9929074bcbb77a49c041582daae0e8
+Author: Panu Matilainen <pmatilai@redhat.com>
+Date:   Tue Feb 5 10:11:19 2013 +0200
+
+    Check for stale db locks when opening write-cursors
+    
+    - During long-running transactions its entirely possible for some
+      other player to come and go leaving stale locks behind and cause
+      the transaction to get stuck until the cavalry comes along in the
+      form of somebody else opening the rpmdb, clearing the blockage.
+    - Presumably dbenv->failchk() is not entirely free of cost so we only
+      do this for writes which are way more critical and also more prone to
+      getting stuck.
+    - dbenv->failchk() could return DB_RUNRECOVER in which case we should
+      abort everything but we lack a mechanism to do it... just add
+      a reminder comment for now.
+
+diff --git a/lib/backend/db3.c b/lib/backend/db3.c
+index 656486b..de8071b 100644
+--- a/lib/backend/db3.c
++++ b/lib/backend/db3.c
+@@ -248,7 +248,7 @@ dbiCursor dbiCursorInit(dbiIndex dbi, unsigned int flags)
+ 	DB * db = dbi->dbi_db;
+ 	DBC * cursor;
+ 	int cflags;
+-	int rc;
++	int rc = 0;
+ 	uint32_t eflags = db_envflags(db);
+ 	
+        /* DB_WRITECURSOR requires CDB and writable db */
+@@ -259,8 +259,23 @@ dbiCursor dbiCursorInit(dbiIndex dbi, unsigned int flags)
+ 	} else
+ 	    cflags = 0;
+ 
+-	rc = db->cursor(db, NULL, &cursor, cflags);
+-	rc = cvtdberr(dbi, "db->cursor", rc, _debug);
++	/*
++	 * Check for stale locks which could block writes "forever".
++	 * XXX: Should we also do this on reads? Reads are less likely
++	 *      to get blocked so it seems excessive...
++	 * XXX: On DB_RUNRECOVER, we should abort everything. Now
++	 *      we'll just fail to open a cursor again and again and again.
++	 */
++	if (cflags & DB_WRITECURSOR) {
++	    DB_ENV *dbenv = db->get_env(db);
++	    rc = dbenv->failchk(dbenv, 0);
++	    rc = cvtdberr(dbi, "dbenv->failchk", rc, _debug);
++	}
++
++	if (rc == 0) {
++	    rc = db->cursor(db, NULL, &cursor, cflags);
++	    rc = cvtdberr(dbi, "db->cursor", rc, _debug);
++	}
+ 
+ 	if (rc == 0) {
+ 	    dbc = xcalloc(1, sizeof(*dbc));

rpm.spec

@@ -21,7 +21,7 @@
 Summary: The RPM package management system
 Name: rpm
 Version: %{rpmver}
-Release: %{?snapver:0.%{snapver}.}3%{?dist}
+Release: %{?snapver:0.%{snapver}.}4%{?dist}
 Group: System Environment/Base
 Url: http://www.rpm.org/
 Source0: http://rpm.org/releases/testing/%{name}-%{srcver}.tar.bz2
@@ -47,6 +47,8 @@ Patch6: rpm-4.9.0-armhfp-logic.patch
 # Patches already in upstream
 # http://www.rpm.org/ticket/865
 Patch100: 0001-Finish-lua-5.2-support-trac-865.patch
+# Check for stale locks when opening write-cursors
+Patch101: rpm-4.11.x-cursor-failchk.patch
 
 # These are not yet upstream
 Patch301: rpm-4.6.0-niagara.patch
@@ -226,6 +228,7 @@ packages on a system.
 %patch4 -p1 -b .use-gpg2
 
 %patch100 -p1 -b .lua-5.2
+%patch101 -p1 -b .cursor-failchk
 
 %patch301 -p1 -b .niagara
 %patch302 -p1 -b .geode
@@ -459,6 +462,9 @@ exit 0
 %doc COPYING doc/librpm/html/*
 
 %changelog
+* Thu May 16 2013 Panu Matilainen <pmatilai@redhat.com> - - 4.11.0.1-4
+- check for stale locks when opening write-cursors (#860500, #962750...)
+
 * Fri May 10 2013 Tom Callaway <spot@fedoraproject.org> - 4.11.0.1-3
 - lua 5.2 fix from upstream