From a932c70a76846aa7dbb4b783291b44bfc8cbd76c Mon Sep 17 00:00:00 2001
From: Jan Synacek <jsynacek@redhat.com>
Date: Mon, 1 Feb 2016 09:25:22 +0100
Subject: [PATCH] journalctl: show friendly info when using -b on runtime
 journal only

Make it clear that specifing boot when there is actually only one has no
effect. This cosmetic patch improves user experience a bit.

Cherry-picked from: 0f1a9a830c87d8accdc3a44d0a93ad343e52a7bd
Resolves: #1082179
---
 src/journal/journalctl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 964f849ee0..836d7d2141 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -1905,6 +1905,13 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
+        if (arg_boot_offset != 0 &&
+            sd_journal_has_runtime_files(j) > 0 &&
+            sd_journal_has_persistent_files(j) == 0) {
+                log_info("Specifying boot ID has no effect, no persistent journal was found");
+                r = 0;
+                goto finish;
+        }
         /* add_boot() must be called first!
          * It may need to seek the journal to find parent boot IDs. */
         r = add_boot(j);