From: Sage Weil <sage@newdream.net>
Date: Fri, 25 Mar 2011 20:27:48 +0000 (-0700)
Subject: ceph: flush msgr_wq during mds_client shutdown
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ef550f6f4f6c9345a27ec85d98f4f7de1adce79c;p=linux-beck.git

ceph: flush msgr_wq during mds_client shutdown

The release method for mds connections uses a backpointer to the
mds_client, so we need to flush the workqueue of any pending work (and
ceph_connection references) prior to freeing the mds_client.  This fixes
an oops easily triggered under UML by

 while true ; do mount ... ; umount ... ; done

Also fix an outdated comment: the flush in ceph_destroy_client only flushes
OSD connections out.  This bug is basically an artifact of the ceph ->
ceph+libceph conversion.

Signed-off-by: Sage Weil <sage@newdream.net>
---

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index a1ee8fa3a8e7..f60b07b0feb0 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3215,9 +3215,15 @@ void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
 {
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 
+	dout("mdsc_destroy %p\n", mdsc);
 	ceph_mdsc_stop(mdsc);
+
+	/* flush out any connection work with references to us */
+	ceph_msgr_flush();
+
 	fsc->mdsc = NULL;
 	kfree(mdsc);
+	dout("mdsc_destroy %p done\n", mdsc);
 }
 
 
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 95f96ab94bba..9bbb356b12e7 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -394,8 +394,8 @@ void ceph_destroy_client(struct ceph_client *client)
 	ceph_osdc_stop(&client->osdc);
 
 	/*
-	 * make sure mds and osd connections close out before destroying
-	 * the auth module, which is needed to free those connections'
+	 * make sure osd connections close out before destroying the
+	 * auth module, which is needed to free those connections'
 	 * ceph_authorizers.
 	 */
 	ceph_msgr_flush();