From 883430534fde5adb06d601e2808cff83ca499984 Mon Sep 17 00:00:00 2001
From: adilger <adilger>
Date: Wed, 24 Apr 2002 20:16:19 +0000
Subject: [PATCH] Add client RPC xid to per-client last_rcvd data.  If the MDS
 dies but the client lives, the on-disk xid tells the client which operations
 the MDS has completed, even if the client never got a reply (hence no
 last_rcvd #).

---
 lustre/include/linux/lustre_mds.h | 11 ++++++-----
 lustre/mds/mds_reint.c            |  1 +
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/lustre/include/linux/lustre_mds.h b/lustre/include/linux/lustre_mds.h
index 3f4b4c2..4f9e3e3b 100644
--- a/lustre/include/linux/lustre_mds.h
+++ b/lustre/include/linux/lustre_mds.h
@@ -65,22 +65,23 @@ struct mds_update_record {
 
 #define MDS_MOUNT_RECOV 2
 
-/* Data stored per server at the head of the last_rcvd file */
+/* Data stored per server at the head of the last_rcvd file.  In le32 order. */
 struct mds_server_data {
         __u8 msd_uuid[37];      /* server UUID */
-        __u8 uuid_padding[3];
+        __u8 uuid_padding[3];   /* unused */
         __u64 msd_last_rcvd;    /* last completed transaction ID */
         __u64 msd_mount_count;  /* MDS incarnation number */
         __u8 padding[512 - 56];
 };
 
-/* Data stored per client in the last_rcvd file */
+/* Data stored per client in the last_rcvd file.  In le32 order. */
 struct mds_client_data {
         __u8 mcd_uuid[37];      /* client UUID */
-        __u8 uuid_padding[3];   /* in case we decide to store UUIDs as ASCII */
+        __u8 uuid_padding[3];   /* unused */
         __u64 mcd_last_rcvd;    /* last completed transaction ID */
         __u64 mcd_mount_count;  /* MDS incarnation number */
-        __u8 padding[MDS_LR_SIZE - 56];
+        __u32 mcd_xid;          /* client RPC xid for the last transaction */
+        __u8 padding[MDS_LR_SIZE - 60];
 };
 
 /* In-memory access to client data from MDS struct */
diff --git a/lustre/mds/mds_reint.c b/lustre/mds/mds_reint.c
index d9c0dd2..a6bf9db 100644
--- a/lustre/mds/mds_reint.c
+++ b/lustre/mds/mds_reint.c
@@ -52,6 +52,7 @@ int mds_update_last_rcvd(struct mds_obd *mds, struct ptlrpc_request *req)
         ++mds->mds_last_rcvd;   /* lock this, or make it an LDLM function? */
         mci->mci_mcd->mcd_last_rcvd = cpu_to_le64(mds->mds_last_rcvd);
         mci->mci_mcd->mcd_mount_count = cpu_to_le64(mds->mds_mount_count);
+        mci->mci_mcd->mcd_xid = cpu_to_le32(req->rq_connection->c_xid_in);
         rc = lustre_fwrite(mds->mds_rcvd_filp, (char *)mci->mci_mcd,
                            sizeof(*mci->mci_mcd), &off);
         CDEBUG(D_INODE, "wrote trans #%Ld for client '%s' at %Ld: rc = %d\n",
-- 
1.8.3.1