[PATCH v2 19/19] NFS: Record task, client ID, and XID in xdr_status trace points

[Chuck Lever <chuck.lever@oracle.com>]

When triggering an nfs_xdr_status trace point, record the task ID
and XID of the failing RPC to better pinpoint the problem.

This feels like a bit of a layering violation.

Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfs/nfs2xdr.c   |    2 +-
 fs/nfs/nfs3xdr.c   |    2 +-
 fs/nfs/nfs4trace.h |   15 +++++++++++++--
 fs/nfs/nfs4xdr.c   |    2 +-
 fs/nfs/nfstrace.h  |   15 +++++++++++++--
 5 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 572794d..cbc17a2 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -151,7 +151,7 @@ static int decode_stat(struct xdr_stream *xdr, enum nfs_stat *status)
 	return 0;
 out_status:
 	*status = be32_to_cpup(p);
-	trace_nfs_xdr_status((int)*status);
+	trace_nfs_xdr_status(xdr, (int)*status);
 	return 0;
 }
 
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index abbbdde..6027678 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -343,7 +343,7 @@ static int decode_nfsstat3(struct xdr_stream *xdr, enum nfs_stat *status)
 	return 0;
 out_status:
 	*status = be32_to_cpup(p);
-	trace_nfs_xdr_status((int)*status);
+	trace_nfs_xdr_status(xdr, (int)*status);
 	return 0;
 }
 
diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index 9a01731..6cba216 100644
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@@ -564,24 +564,35 @@
 
 TRACE_EVENT(nfs4_xdr_status,
 		TP_PROTO(
+			const struct xdr_stream *xdr,
 			u32 op,
 			int error
 		),
 
-		TP_ARGS(op, error),
+		TP_ARGS(xdr, op, error),
 
 		TP_STRUCT__entry(
+			__field(unsigned int, task_id)
+			__field(unsigned int, client_id)
+			__field(u32, xid)
 			__field(u32, op)
 			__field(unsigned long, error)
 		),
 
 		TP_fast_assign(
+			const struct rpc_rqst *rqstp = xdr->rqst;
+			const struct rpc_task *task = rqstp->rq_task;
+
+			__entry->task_id = task->tk_pid;
+			__entry->client_id = task->tk_client->cl_clid;
+			__entry->xid = be32_to_cpu(rqstp->rq_xid);
 			__entry->op = op;
 			__entry->error = error;
 		),
 
 		TP_printk(
-			"error=%lu (%s) operation %d:",
+			"task:%u@%d xid=0x%08x error=%lu (%s) operation=%d",
+			__entry->task_id, __entry->client_id, __entry->xid,
 			__entry->error, show_nfsv4_errors(__entry->error),
 			__entry->op
 		)
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 6024461..d974ff3 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3187,7 +3187,7 @@ static bool __decode_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 	return true;
 out_status:
 	nfserr = be32_to_cpup(p);
-	trace_nfs4_xdr_status(opnum, nfserr);
+	trace_nfs4_xdr_status(xdr, opnum, nfserr);
 	*nfs_retval = nfs4_stat_to_errno(nfserr);
 	return true;
 out_bad_operation:
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 3a0ed3d..84a79ba 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -1111,21 +1111,32 @@
 
 TRACE_EVENT(nfs_xdr_status,
 		TP_PROTO(
+			const struct xdr_stream *xdr,
 			int error
 		),
 
-		TP_ARGS(error),
+		TP_ARGS(xdr, error),
 
 		TP_STRUCT__entry(
+			__field(unsigned int, task_id)
+			__field(unsigned int, client_id)
+			__field(u32, xid)
 			__field(unsigned long, error)
 		),
 
 		TP_fast_assign(
+			const struct rpc_rqst *rqstp = xdr->rqst;
+			const struct rpc_task *task = rqstp->rq_task;
+
+			__entry->task_id = task->tk_pid;
+			__entry->client_id = task->tk_client->cl_clid;
+			__entry->xid = be32_to_cpu(rqstp->rq_xid);
 			__entry->error = error;
 		),
 
 		TP_printk(
-			"error=%lu (%s)",
+			"task:%u@%d xid=0x%08x error=%lu (%s)",
+			__entry->task_id, __entry->client_id, __entry->xid,
 			__entry->error, nfs_show_status(__entry->error)
 		)
 );