75 lines
3.0 KiB
Diff
75 lines
3.0 KiB
Diff
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From 53113dc8254cae9a27e321e539d2d876677e61b9 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
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Date: Fri, 7 Jun 2013 22:01:03 -0400
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Subject: [PATCH] journal: letting (interleaved) seqnums go
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In the following scenario:
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server creates system.journal
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server creates user-1000.journal
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both journals share the same seqnum_id.
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Then
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server writes to user-1000.journal first,
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and server writes to system.journal a bit later,
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and everything is fine.
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The server then terminates (crash, reboot, rsyslog testing,
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whatever), and user-1000.journal has entries which end with
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a lower seqnum than system.journal. Now
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server is restarted
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server opens user-1000.journal and writes entries to it...
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BAM! duplicate seqnums for the same seqnum_id.
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Now, we usually don't see that happen, because system.journal
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is closed last, and opened first. Since usually at least one
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message is written during boot and lands in the system.journal,
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the seqnum is initialized from it, and is set to a number higher
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than than anything found in user journals. Nevertheless, if
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system.journal is corrupted and is rotated, it can happen that
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an entry is written to the user journal with a seqnum that is
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a duplicate with an entry found in the corrupted system.journal~.
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When browsing the journal, journalctl can fall into a loop
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where it tries to follow the seqnums, and tries to go the
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next location by seqnum, and is transported back in time to
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to the older duplicate seqnum. There is not way to find
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out the maximum seqnum used in a multiple files, without
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actually looking at all of them. But we don't want to do
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that because it would be slow, and actually it isn't really
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possible, because a file might e.g. be temporarily unaccessible.
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Fix the problem by using different seqnum series for user
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journals. Using the same seqnum series for rotated journals
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is still fine, because we know that nothing will write
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to the rotated journal anymore.
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Likely related:
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https://bugs.freedesktop.org/show_bug.cgi?id=64566
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https://bugs.freedesktop.org/show_bug.cgi?id=59856
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https://bugs.freedesktop.org/show_bug.cgi?id=64296
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https://bugs.archlinux.org/task/35581
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https://bugzilla.novell.com/show_bug.cgi?id=817778
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Possibly related:
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https://bugs.freedesktop.org/show_bug.cgi?id=64293
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Conflicts:
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src/journal/journald-server.c
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---
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src/journal/journald-server.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
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index cc52b8a..cde63c8 100644
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--- a/src/journal/journald-server.c
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+++ b/src/journal/journald-server.c
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@@ -280,7 +280,7 @@ static JournalFile* find_journal(Server *s, uid_t uid) {
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journal_file_close(f);
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}
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- r = journal_file_open_reliably(p, O_RDWR|O_CREAT, 0640, s->compress, s->seal, &s->system_metrics, s->mmap, s->system_journal, &f);
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+ r = journal_file_open_reliably(p, O_RDWR|O_CREAT, 0640, s->compress, s->seal, &s->system_metrics, s->mmap, NULL, &f);
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free(p);
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if (r < 0)
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--
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1.8.2.1
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