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ceph: initialize client debugfs outside of monc->mutex

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Initializing debufs under monc->mutex introduces a lock dependency for
sb->s_type->i_mutex_key, which (combined with several other dependencies)
leads to an annoying lockdep warning.  There's no particular reason to do
the debugfs setup under this lock, so move it out.

It used to be the case that our first monmap could come from the OSD; that
is no longer the case with recent servers, so we will reliably set up the
client entry during the initial authentication.

We don't have to worry about racing with debugfs teardown by
ceph_debugfs_client_cleanup() because ceph_destroy_client() calls
ceph_msgr_flush() first, which will wait for the message dispatch work
to complete (and the debugfs init to complete).

Fixes: #1940
Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2012-01-13 22:22:03 -08:00
parent 114fc47492
commit ab434b60ab
2 changed files with 12 additions and 3 deletions
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2
net/ceph/ceph_common.c
View file

@ -85,8 +85,6 @@ int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid)
} else {
pr_info("client%lld fsid %pU\n", ceph_client_id(client), fsid);
memcpy(&client->fsid, fsid, sizeof(*fsid));
ceph_debugfs_client_init(client);
client->have_fsid = true;
}
return 0;
}

13
net/ceph/mon_client.c
View file

@ -8,8 +8,8 @@
#include <linux/ceph/mon_client.h>
#include <linux/ceph/libceph.h>
#include <linux/ceph/debugfs.h>
#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>
/*
@ -340,8 +340,19 @@ static void ceph_monc_handle_map(struct ceph_mon_client *monc,
client->monc.monmap = monmap;
kfree(old);
if (!client->have_fsid) {
client->have_fsid = true;
mutex_unlock(&monc->mutex);
/*
* do debugfs initialization without mutex to avoid
* creating a locking dependency
*/
ceph_debugfs_client_init(client);
goto out_unlocked;
}
out:
mutex_unlock(&monc->mutex);
out_unlocked:
wake_up_all(&client->auth_wq);
}