From d66bbd441c08fe00ed2add1cf70cb243ebc2b27e Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@newdream.net>
Date: Fri, 21 Jan 2011 21:16:46 -0800
Subject: [PATCH] ceph: avoid picking MDS that is not active

Ignore replication or auth frag data if it indicates an MDS that is not
active.  This can happen if the MDS shuts down and the client has stale
data about the namespace distribution across the MDS cluster.  If that's
the case, fall back to directing the request based on the auth cap (which
should always be accurate).

Signed-off-by: Sage Weil <sage@newdream.net>
---
 fs/ceph/mds_client.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 509339ceef72..a6949cc7c69a 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -693,9 +693,11 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 				dout("choose_mds %p %llx.%llx "
 				     "frag %u mds%d (%d/%d)\n",
 				     inode, ceph_vinop(inode),
-				     frag.frag, frag.mds,
+				     frag.frag, mds,
 				     (int)r, frag.ndist);
-				return mds;
+				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
+				    CEPH_MDS_STATE_ACTIVE)
+					return mds;
 			}
 
 			/* since this file/dir wasn't known to be
@@ -708,7 +710,9 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 				dout("choose_mds %p %llx.%llx "
 				     "frag %u mds%d (auth)\n",
 				     inode, ceph_vinop(inode), frag.frag, mds);
-				return mds;
+				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
+				    CEPH_MDS_STATE_ACTIVE)
+					return mds;
 			}
 		}
 	}
-- 
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