From edd23b38148bf7bddc3727adda8f33f43e0d3287 Mon Sep 17 00:00:00 2001
From: shadow <shadow>
Date: Thu, 17 Sep 2009 09:27:06 +0000
Subject: [PATCH] Don't allow make backward step on assiging osc next id.

Branch b_release_1_8_1
b=19557
i=tappro
i=jay
---
 lustre/ChangeLog         |  6 ++++++
 lustre/osc/osc_request.c | 16 ++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index 85d146d..adb076d 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -15,6 +15,12 @@ TBD Sun Microsystems, Inc.
 	* ext4 support for RHEL5 is experimental and thus should not be
 	  used in production.
 
+Severity   : normal
+Bugzilla   : 19557
+Description: Don't allow make backward step on assiging osc next id.
+Details    : race between allocation next id and ll_sync thread can be cause
+             of set wrong osc next id and can be kill valid ost objects.
+
 Severity   : enhancement
 Bugzilla   : 20400
 Description: Update kernel to RHEL5 2.6.18-128.7.1.el5.
diff --git a/lustre/osc/osc_request.c b/lustre/osc/osc_request.c
index 31de776..eec906b 100644
--- a/lustre/osc/osc_request.c
+++ b/lustre/osc/osc_request.c
@@ -3945,18 +3945,30 @@ static int osc_set_info_async(struct obd_export *exp, obd_count keylen,
         OBD_FAIL_TIMEOUT(OBD_FAIL_OSC_SHUTDOWN, 10);
 
         if (KEY_IS(KEY_NEXT_ID)) {
+                obd_id new_val;
+                struct osc_creator *oscc = &obd->u.cli.cl_oscc;
+
                 if (vallen != sizeof(obd_id))
                         RETURN(-EINVAL);
-                obd->u.cli.cl_oscc.oscc_next_id = *((obd_id*)val) + 1;
+
+                /* avoid race between allocate new object and set next id
+                 * from ll_sync thread */
+                spin_lock(&oscc->oscc_lock);
+                new_val = *((obd_id*)val) + 1;
+                if (new_val >= oscc->oscc_next_id);
+                        oscc->oscc_next_id = new_val;
+                spin_unlock(&oscc->oscc_lock);
+
                 CDEBUG(D_HA, "%s: set oscc_next_id = "LPU64"\n",
                        exp->exp_obd->obd_name,
-                       obd->u.cli.cl_oscc.oscc_next_id);
+                       oscc->oscc_next_id);
 
                 RETURN(0);
         }
 
         if (KEY_IS(KEY_UNLINKED)) {
                 struct osc_creator *oscc = &obd->u.cli.cl_oscc;
+
                 spin_lock(&oscc->oscc_lock);
                 oscc->oscc_flags &= ~OSCC_FLAG_NOSPC;
                 spin_unlock(&oscc->oscc_lock);
-- 
1.8.3.1