From: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Date: Sat, 28 Sep 2013 13:58:45 +0000 (+0400)
Subject: LU-4019 ofd: setattr don't udpate lvbo with object referenced
X-Git-Tag: 2.5.0~19
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=a4e8e2f71fb64e293cbf8db07f4608646fd7acd4;hp=02a976b13d16fac7708fbd1827fcc6129b7e20f3

LU-4019 ofd: setattr don't udpate lvbo with object referenced

we shouldn't allow recursive lu_object_find() while object
can be destroyed. so release the reference to the object
before calling to ldlm_res_lvbo_update() which lookups the
object on its own.

Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Change-Id: If34d89834e352b6d0b8129a6fb4377317833a78a
Reviewed-on: http://review.whamcloud.com/7795
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/ofd/ofd_obd.c b/lustre/ofd/ofd_obd.c
index c0a6fcd..8bcbd06 100644
--- a/lustre/ofd/ofd_obd.c
+++ b/lustre/ofd/ofd_obd.c
@@ -887,12 +887,6 @@ int ofd_setattr(const struct lu_env *env, struct obd_export *exp,
 	if (rc)
 		GOTO(out_unlock, rc);
 
-	res = ldlm_resource_get(ns, NULL, &info->fti_resid, LDLM_EXTENT, 0);
-	if (res != NULL) {
-		ldlm_res_lvbo_update(res, NULL, 0);
-		ldlm_resource_putref(res);
-	}
-
 	ofd_info2oti(info, oti);
 
 	ofd_counter_incr(exp, LPROC_OFD_STATS_SETATTR, oti->oti_jobid, 1);
@@ -900,6 +894,19 @@ int ofd_setattr(const struct lu_env *env, struct obd_export *exp,
 out_unlock:
 	ofd_object_put(env, fo);
 out:
+	if (rc == 0) {
+		/* we do not call this before to avoid lu_object_find() in
+		 *  ->lvbo_update() holding another reference on the object.
+		 * otherwise concurrent destroy can make the object unavailable
+		 * for 2nd lu_object_find() waiting for the first reference
+		 * to go... deadlock! */
+		res = ldlm_resource_get(ns, NULL, &info->fti_resid, LDLM_EXTENT, 0);
+		if (res != NULL) {
+			ldlm_res_lvbo_update(res, NULL, 0);
+			ldlm_resource_putref(res);
+		}
+	}
+
 	return rc;
 }