From: Fan Yong <fan.yong@intel.com>
Date: Tue, 8 Nov 2016 16:47:59 +0000 (+0800)
Subject: LU-9224 fid: race between client_fid_fini and seq_client_flush
X-Git-Tag: 2.9.55~3
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=c0d30fc79be0788fca19bfa7e3b5048881195fc6

LU-9224 fid: race between client_fid_fini and seq_client_flush

When the client mount failed or umount, the client_fid_fini() will
be called. At that time, the async connection failure will trigger
seq_client_flush() which parameter may have been released by the
client_fid_fini() by race.

Introduce client_obd::cl_seq_rwsem to protect client_obd::cl_seq.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I96b195676b0d1356a8ae7438cdf69d2e258abd23
Reviewed-on: https://review.whamcloud.com/26079
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/fid/fid_request.c b/lustre/fid/fid_request.c
index 4e34794..28a6b1e 100644
--- a/lustre/fid/fid_request.c
+++ b/lustre/fid/fid_request.c
@@ -544,26 +544,30 @@ int client_fid_init(struct obd_device *obd,
 	int rc;
 	ENTRY;
 
+	down_write(&cli->cl_seq_rwsem);
 	OBD_ALLOC_PTR(cli->cl_seq);
-	if (cli->cl_seq == NULL)
-		RETURN(-ENOMEM);
+	if (!cli->cl_seq)
+		GOTO(out, rc = -ENOMEM);
 
 	OBD_ALLOC(prefix, MAX_OBD_NAME + 5);
-	if (prefix == NULL)
-		GOTO(out_free_seq, rc = -ENOMEM);
+	if (!prefix)
+		GOTO(out, rc = -ENOMEM);
 
 	snprintf(prefix, MAX_OBD_NAME + 5, "cli-%s", obd->obd_name);
 
 	/* Init client side sequence-manager */
 	rc = seq_client_init(cli->cl_seq, exp, type, prefix, NULL);
 	OBD_FREE(prefix, MAX_OBD_NAME + 5);
-	if (rc)
-		GOTO(out_free_seq, rc);
 
-	RETURN(rc);
-out_free_seq:
-	OBD_FREE_PTR(cli->cl_seq);
-	cli->cl_seq = NULL;
+	GOTO(out, rc);
+
+out:
+	if (rc && cli->cl_seq) {
+		OBD_FREE_PTR(cli->cl_seq);
+		cli->cl_seq = NULL;
+	}
+	up_write(&cli->cl_seq_rwsem);
+
 	return rc;
 }
 EXPORT_SYMBOL(client_fid_init);
@@ -573,11 +577,13 @@ int client_fid_fini(struct obd_device *obd)
 	struct client_obd *cli = &obd->u.cli;
 	ENTRY;
 
-	if (cli->cl_seq != NULL) {
+	down_write(&cli->cl_seq_rwsem);
+	if (cli->cl_seq) {
 		seq_client_fini(cli->cl_seq);
 		OBD_FREE_PTR(cli->cl_seq);
 		cli->cl_seq = NULL;
 	}
+	up_write(&cli->cl_seq_rwsem);
 
 	RETURN(0);
 }
diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 77c61b3..b399149 100644
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -323,6 +323,7 @@ struct client_obd {
 
 	/* sequence manager */
 	struct lu_client_seq    *cl_seq;
+	struct rw_semaphore	 cl_seq_rwsem;
 
 	atomic_t             cl_resends; /* resend count */
 
diff --git a/lustre/ldlm/ldlm_lib.c b/lustre/ldlm/ldlm_lib.c
index 3677da1..ced1198 100644
--- a/lustre/ldlm/ldlm_lib.c
+++ b/lustre/ldlm/ldlm_lib.c
@@ -350,10 +350,12 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
 
 	init_rwsem(&cli->cl_sem);
 	mutex_init(&cli->cl_mgc_mutex);
-        cli->cl_conn_count = 0;
-        memcpy(server_uuid.uuid, lustre_cfg_buf(lcfg, 2),
-               min_t(unsigned int, LUSTRE_CFG_BUFLEN(lcfg, 2),
-                     sizeof(server_uuid)));
+	cli->cl_seq = NULL;
+	init_rwsem(&cli->cl_seq_rwsem);
+	cli->cl_conn_count = 0;
+	memcpy(server_uuid.uuid, lustre_cfg_buf(lcfg, 2),
+	       min_t(unsigned int, LUSTRE_CFG_BUFLEN(lcfg, 2),
+		     sizeof(server_uuid)));
 
 	cli->cl_dirty_pages = 0;
 	cli->cl_avail_grant = 0;
diff --git a/lustre/mdc/mdc_request.c b/lustre/mdc/mdc_request.c
index 2426ce8..2c45545 100644
--- a/lustre/mdc/mdc_request.c
+++ b/lustre/mdc/mdc_request.c
@@ -2516,8 +2516,10 @@ static int mdc_import_event(struct obd_device *obd, struct obd_import *imp,
 		 * Flush current sequence to make client obtain new one
 		 * from server in case of disconnect/reconnect.
 		 */
-		if (cli->cl_seq != NULL)
+		down_read(&cli->cl_seq_rwsem);
+		if (cli->cl_seq)
 			seq_client_flush(cli->cl_seq);
+		up_read(&cli->cl_seq_rwsem);
 
 		rc = obd_notify_observer(obd, obd, OBD_NOTIFY_INACTIVE);
 		break;
@@ -2553,9 +2555,16 @@ int mdc_fid_alloc(const struct lu_env *env, struct obd_export *exp,
 		  struct lu_fid *fid, struct md_op_data *op_data)
 {
 	struct client_obd *cli = &exp->exp_obd->u.cli;
-	struct lu_client_seq *seq = cli->cl_seq;
+	int rc = -EIO;
+
 	ENTRY;
-	RETURN(seq_client_alloc_fid(env, seq, fid));
+
+	down_read(&cli->cl_seq_rwsem);
+	if (cli->cl_seq)
+		rc = seq_client_alloc_fid(env, cli->cl_seq, fid);
+	up_read(&cli->cl_seq_rwsem);
+
+	RETURN(rc);
 }
 
 static struct obd_uuid *mdc_get_uuid(struct obd_export *exp)