Flush and reset any current filter before applying new filter (#1135)

As per systemd man: sd_journal_flush_matches() may be used to flush all matches, disjunction and conjunction terms again. After this call all filtering is removed and all entries in the journal will be iterated again.

Signed-off-by: David Howell <[email protected]>

Author: dbhowell

lib/journald/src/lib.rs

@@ -159,13 +159,13 @@ impl Journal {
 
         // Journald does not guarantee that the following records are
         // only from the current boot, so a filter is also needed.
+        self.lib.sd_journal_flush_matches(self.journal);
         let filter = format!("_BOOT_ID={}", boot_str);
         sd_result(self.lib.sd_journal_add_match(
             self.journal,
             filter.as_ptr() as *const c_void,
             filter.len(),
         ))?;
-        self.lib.sd_journal_flush_matches(self.journal);
 
         Ok(())
     }