From 6cf3890ceb0ce907a5713f83b3af85ac247b1703 Mon Sep 17 00:00:00 2001
From: shadow <shadow>
Date: Thu, 17 Sep 2009 08:21:53 +0000
Subject: [PATCH] Don't allow make backward step on assigning osc next id.

Branch b1_8
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 2092d93..83796db 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -14,6 +14,12 @@ tbd Sun Microsystems, Inc.
 	  of Lustre filesystem with 4K stack may cause a stack overflow. For
 	  more information, please refer to bugzilla 17630.
 
+Severity   : normal
+Bugzilla   : 19557
+Description: Don't allow make backward step on assign 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   : 20200
 Description: Added sanity-quota test to for lfs(1) to work with numeric uid/gid.
diff --git a/lustre/osc/osc_request.c b/lustre/osc/osc_request.c
index 1285272..5ab3e72 100644
--- a/lustre/osc/osc_request.c
+++ b/lustre/osc/osc_request.c
@@ -3984,18 +3984,30 @@ 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