[PATCH 04/17] perf data: Fail check_backup in case of error

[Jiri Olsa <jolsa@kernel.org>]

And display the error message from removing
the old data file:

  $ perf record ls
  Can't remove old data: Permission denied (perf.data.old)
  Perf session creation failed.

Not sure how to make fail the rename (after we successfully
remove the destination file/dir) to show the message,
anyway let's have it there.

Link: http://lkml.kernel.org/n/tip-6k0tikvlyugms7xxqs794jxz@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/data.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 0a3051cc0ea0..18e5d94b0e97 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -41,12 +41,24 @@ static int check_backup(struct perf_data *data)
 		return 0;
 
 	if (!stat(data->path, &st) && st.st_size) {
-		/* TODO check errors properly */
 		char oldname[PATH_MAX];
+
 		snprintf(oldname, sizeof(oldname), "%s.old",
 			 data->path);
-		rm_rf(oldname);
-		rename(data->path, oldname);
+
+		if (rm_rf(oldname)) {
+			pr_err("Can't remove old data: %s (%s)\n",
+			       strerror(errno), oldname);
+
+			return -1;
+		}
+
+		if (rename(data->path, oldname)) {
+			pr_err("Can't move data: %s (%s to %s)\n",
+			       strerror(errno),
+			       data->path, oldname);
+			return -1;
+		}
 	}
 
 	return 0;
-- 
2.17.2