[tip:perf/core] perf data: Fail check_backup in case of error

[tip-bot for Jiri Olsa <tipbot@xxxxxxxxx>]

Commit-ID:  ccb7a71dcea071c7fd68192909c4e54561c88043
Gitweb:     https://git.kernel.org/tip/ccb7a71dcea071c7fd68192909c4e54561c88043
Author:     Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Sun, 24 Feb 2019 20:06:43 +0100
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 25 Feb 2019 10:37:01 -0300

perf data: Fail check_backup in case of error

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.

  $ perf record ls
  Can't remove old data: Unknown file found (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.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20190224190656.30163-8-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/data.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index bbf9a299615e..d008c3973012 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -41,12 +41,27 @@ 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];
+		int ret;
+
 		snprintf(oldname, sizeof(oldname), "%s.old",
 			 data->path);
-		rm_rf_perf_data(oldname);
-		rename(data->path, oldname);
+
+		ret = rm_rf_perf_data(oldname);
+		if (ret) {
+			pr_err("Can't remove old data: %s (%s)\n",
+			       ret == -2 ?
+			       "Unknown file found" : 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;