From 98169577b83b45a40105cf58e6cffe0272074817 Mon Sep 17 00:00:00 2001

From: Peter Portante <peter.a.portante@gmail.com>

Date: Sun, 28 Jan 2018 16:48:04 -0500

Subject: [PATCH] journalctl: Periodically call sd_journal_process in

 journalctl

If `journalctl` take a long time to process messages, and during that

time journal file rotation occurs, a `journalctl` client will keep

those rotated files open until it calls `sd_journal_process()`, which

typically happens as a result of calling `sd_journal_wait()` below in

the "following" case.  By periodically calling `sd_journal_process()`

during the processing loop we shrink the window of time a client

instance has open file descriptors for rotated (deleted) journal

files.

(Lennart: slightly reworked version, that dropped some of the commenting

which was solved otherwise)

(cherry picked from commit ec316d199a13d8db3f6550d60e369893de2fb417)

Related: #1540538

---

 src/journal/journalctl.c | 16 ++++++++++++++++

 1 file changed, 16 insertions(+)

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c

index 0be70764ef..1e6d0761c7 100644

--- a/src/journal/journalctl.c

+++ b/src/journal/journalctl.c

@@ -67,6 +67,8 @@

 #define DEFAULT_FSS_INTERVAL_USEC (15*USEC_PER_MINUTE)

+#define PROCESS_INOTIFY_INTERVAL 1024   /* Every 1,024 messages processed */

+

 enum {

         /* Special values for arg_lines */

         ARG_LINES_DEFAULT = -2,

@@ -2294,6 +2296,20 @@ int main(int argc, char *argv[]) {

                                 goto finish;

                         n_shown++;

+

+                        /* If journalctl take a long time to process messages, and during that time journal file

+                         * rotation occurs, a journalctl client will keep those rotated files open until it calls

+                         * sd_journal_process(), which typically happens as a result of calling sd_journal_wait() below

+                         * in the "following" case.  By periodically calling sd_journal_process() during the processing

+                         * loop we shrink the window of time a client instance has open file descriptors for rotated

+                         * (deleted) journal files. */

+                        if ((n_shown % PROCESS_INOTIFY_INTERVAL) == 0) {

+                                r = sd_journal_process(j);

+                                if (r < 0) {

+                                        log_error_errno(r, "Failed to process inotify events: %m");

+                                        goto finish;

+                                }

+                        }

                 }

                 if (!arg_follow) {