Btrfs-progs: output the error reason when qgroup_show fails

The original code forgot to output the reason why the commands failed,
fix it.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>

diff --git a/cmds-qgroup.c b/cmds-qgroup.c
index 79888c8..275f00f 100644 (file)
--- a/cmds-qgroup.c
+++ b/cmds-qgroup.c
@@ -298,6 +298,7 @@ static int cmd_qgroup_show(int argc, char **argv)
 {
        int ret = 0;
        int fd;
+       int e;
        char *path = argv[1];
 
        if (check_argc_exact(argc, 2))
@@ -310,9 +311,11 @@ static int cmd_qgroup_show(int argc, char **argv)
        }
 
        ret = list_qgroups(fd);
+       e = errno;
        close(fd);
        if (ret < 0) {
-               fprintf(stderr, "ERROR: can't list qgroups\n");
+               fprintf(stderr, "ERROR: can't list qgroups: %s\n",
+                               strerror(e));
                return 30;
        }