journal: print a useful error message if we hit the journal file open limit

See: #20921
(cherry picked from commit 763c46defa)
(cherry picked from commit 1187340c9d)
(cherry picked from commit 2c984010bc)

src/libsystemd/sd-journal/journal-internal.h

@@ -14,6 +14,8 @@
 #include "list.h"
 #include "set.h"
 
+#define JOURNAL_FILES_MAX 7168u
+
 typedef struct Match Match;
 typedef struct Location Location;
 typedef struct Directory Directory;

src/libsystemd/sd-journal/sd-journal.c

@@ -42,8 +42,6 @@
 #include "strv.h"
 #include "syslog-util.h"
 
-#define JOURNAL_FILES_MAX 7168
-
 #define JOURNAL_FILES_RECHECK_USEC (2 * USEC_PER_SEC)
 
 /* The maximum size of variable values we'll expand in catalog entries. We bind this to PATH_MAX for now, as

src/shared/journal-util.c

@@ -129,6 +129,10 @@ int journal_access_check_and_warn(sd_journal *j, bool quiet, bool want_other_use
                         log_warning_errno(err, "Journal file %s corrupted, ignoring file.", path);
                         break;
 
+                case ETOOMANYREFS:
+                        log_warning_errno(err, "Too many journal files (limit is at %u) in scope, ignoring file '%s'.", JOURNAL_FILES_MAX, path);
+                        break;
+
                 default:
                         log_warning_errno(err, "An error was encountered while opening journal file or directory %s, ignoring file: %m", path);
                         break;