smb3: add trace point for SMB2_set_eof

In order to debug problems with file size being reported incorrectly
temporarily (in this case xfstest generic/584 intermittent failure)
we need to add trace point for the non-compounded code path where
we set the file size (SMB2_set_eof).  The new trace point is:
   "smb3_set_eof"

Here is sample output from the tracepoint:

            TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
              | |         |   |||||     |         |
          xfs_io-75403   [002] ..... 95219.189835: smb3_set_eof: xid=221 sid=0xeef1cbd2 tid=0x27079ee6 fid=0x52edb58c offset=0x100000
 aio-dio-append--75418   [010] ..... 95219.242402: smb3_set_eof: xid=226 sid=0xeef1cbd2 tid=0x27079ee6 fid=0xae89852d offset=0x0
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.c

@@ -5154,6 +5154,8 @@ SMB2_set_eof(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	data = &info;
 	size = sizeof(struct smb2_file_eof_info);
 
+	trace_smb3_set_eof(xid, persistent_fid, tcon->tid, tcon->ses->Suid, le64_to_cpu(*eof));
+
 	return send_set_info(xid, tcon, persistent_fid, volatile_fid,
 			pid, FILE_END_OF_FILE_INFORMATION, SMB2_O_INFO_FILE,
 			0, 1, &data, &size);

fs/cifs/trace.h

@@ -121,6 +121,44 @@ DEFINE_SMB3_RW_DONE_EVENT(query_dir_done);
 DEFINE_SMB3_RW_DONE_EVENT(zero_done);
 DEFINE_SMB3_RW_DONE_EVENT(falloc_done);
 
+/* For logging successful set EOF (truncate) */
+DECLARE_EVENT_CLASS(smb3_eof_class,
+	TP_PROTO(unsigned int xid,
+		__u64	fid,
+		__u32	tid,
+		__u64	sesid,
+		__u64	offset),
+	TP_ARGS(xid, fid, tid, sesid, offset),
+	TP_STRUCT__entry(
+		__field(unsigned int, xid)
+		__field(__u64, fid)
+		__field(__u32, tid)
+		__field(__u64, sesid)
+		__field(__u64, offset)
+	),
+	TP_fast_assign(
+		__entry->xid = xid;
+		__entry->fid = fid;
+		__entry->tid = tid;
+		__entry->sesid = sesid;
+		__entry->offset = offset;
+	),
+	TP_printk("xid=%u sid=0x%llx tid=0x%x fid=0x%llx offset=0x%llx",
+		__entry->xid, __entry->sesid, __entry->tid, __entry->fid,
+		__entry->offset)
+)
+
+#define DEFINE_SMB3_EOF_EVENT(name)         \
+DEFINE_EVENT(smb3_eof_class, smb3_##name,   \
+	TP_PROTO(unsigned int xid,		\
+		__u64	fid,			\
+		__u32	tid,			\
+		__u64	sesid,			\
+		__u64	offset),		\
+	TP_ARGS(xid, fid, tid, sesid, offset))
+
+DEFINE_SMB3_EOF_EVENT(set_eof);
+
 /*
  * For handle based calls other than read and write, and get/set info
  */