From c02e565656ad806e1390b3054c2bc73828220040 Mon Sep 17 00:00:00 2001
From: bwzhou <bwzhou>
Date: Tue, 10 Jun 2008 07:42:25 +0000
Subject: [PATCH] Branch HEAD b=15759 r=rread, green

Description: MDS or OSS service threads fail startup with -24 (-EMFILE)
Details    : During startup under recovery, it is possible for service
             thread startup to fail in ptlrpc_start_threads() if one
             of the threads begins processing a request and then starts
             an additional thread.  This causes ptlrpc_start_threads()
             to try and start 1 too many threads and get an error.
---
 lustre/include/obd_support.h |  1 +
 lustre/ptlrpc/service.c      |  7 ++++++-
 lustre/tests/conf-sanity.sh  | 13 +++++++++++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/lustre/include/obd_support.h b/lustre/include/obd_support.h
index 26e5eb7..853e7a8 100644
--- a/lustre/include/obd_support.h
+++ b/lustre/include/obd_support.h
@@ -243,6 +243,7 @@ int obd_alloc_fail(const void *ptr, const char *name, const char *type,
 #define OBD_FAIL_TGT_DELAY_CONNECT       0x703
 #define OBD_FAIL_TGT_DELAY_RECONNECT     0x704
 #define OBD_FAIL_TGT_DELAY_PRECREATE     0x705
+#define OBD_FAIL_TGT_TOOMANY_THREADS     0x706
 
 #define OBD_FAIL_MDC_REVALIDATE_PAUSE    0x800
 #define OBD_FAIL_MDC_ENQUEUE_PAUSE       0x801
diff --git a/lustre/ptlrpc/service.c b/lustre/ptlrpc/service.c
index 4cda095..46cb740 100644
--- a/lustre/ptlrpc/service.c
+++ b/lustre/ptlrpc/service.c
@@ -1165,6 +1165,9 @@ int ptlrpc_start_threads(struct obd_device *dev, struct ptlrpc_service *svc)
         LASSERT(svc->srv_threads_min > 0);
         for (i = 0; i < svc->srv_threads_min; i++) {
                 rc = ptlrpc_start_thread(dev, svc);
+                /* We have enough threads, don't start more.  b=15759 */
+                if (rc == -EMFILE)
+                        break;
                 if (rc) {
                         CERROR("cannot start %s thread #%d: rc %d\n", 
                                svc->srv_thread_name, i, rc);
@@ -1186,7 +1189,9 @@ int ptlrpc_start_thread(struct obd_device *dev, struct ptlrpc_service *svc)
         CDEBUG(D_RPCTRACE, "%s started %d min %d max %d running %d\n",
                svc->srv_name, svc->srv_threads_started, svc->srv_threads_min,
                svc->srv_threads_max, svc->srv_threads_running);
-        if (svc->srv_threads_started >= svc->srv_threads_max)
+        if (unlikely(svc->srv_threads_started >= svc->srv_threads_max) ||
+            (OBD_FAIL_CHECK(OBD_FAIL_TGT_TOOMANY_THREADS) &&
+             svc->srv_threads_started == svc->srv_threads_min - 1))
                 RETURN(-EMFILE);
 
         OBD_ALLOC_PTR(thread);
diff --git a/lustre/tests/conf-sanity.sh b/lustre/tests/conf-sanity.sh
index 06b00ec..b51b187 100644
--- a/lustre/tests/conf-sanity.sh
+++ b/lustre/tests/conf-sanity.sh
@@ -1559,7 +1559,16 @@ test_39() {
 }
 run_test 39 "leak_finder recognizes both LUSTRE and LNET malloc messages"
 
-test_40() { #bug 14134
+test_40() { # bug 15759
+	start_ost
+	#define OBD_FAIL_TGT_TOOMANY_THREADS     0x706
+	do_facet mds "sysctl -w lustre.fail_loc=0x80000706"
+	start_mds
+	cleanup
+}
+run_test 40 "race during service thread startup"
+
+test_41() { #bug 14134
         local rc
         start mds $MDSDEV $MDS_MOUNT_OPTS -o nosvc
         start ost `ostdevname 1` $OST_MOUNT_OPTS
@@ -1578,7 +1587,7 @@ test_40() { #bug 14134
         unload_modules || return 204
         return $rc
 }
-run_test 40 "mount mds with --nosvc and --nomgs"
+run_test 41 "mount mds with --nosvc and --nomgs"
 
 umount_client $MOUNT
 cleanup_nocli
-- 
1.8.3.1