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36 lines
1.3 KiB
Diff
36 lines
1.3 KiB
Diff
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From b136bff25e93be6f11de74aca03569022364b973 Mon Sep 17 00:00:00 2001
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From: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
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Date: Mon, 25 Feb 2019 20:50:48 +0100
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Subject: [PATCH] pam_tally2: Remove unnecessary fsync()
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pam_tally2 does fsync() after writing to a tally file.
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This causes hard drive cache flushes on every failed SSH login on many
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(if not most) filesystems.
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And an internet-exposed machine can have a lot of these failed logins.
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This operation however doesn't seem to be necessary - the pam_tally2
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module does not do any operation which would need explicit post-crash
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ordering, it just does simple file reads and writes.
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And doing a fsync() after them doesn't close any race if the system happens
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to crash between a write being posted and its fsync() completion.
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Let's remove this operation to get rid of all these extra cache flushes.
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---
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modules/pam_tally2/pam_tally2.c | 4 ----
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1 file changed, 4 deletions(-)
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diff --git a/modules/pam_tally2/pam_tally2.c b/modules/pam_tally2/pam_tally2.c
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index 984edf6a..ce7f5aee 100644
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--- a/modules/pam_tally2/pam_tally2.c
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+++ b/modules/pam_tally2/pam_tally2.c
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@@ -484,10 +484,6 @@ set_tally(pam_handle_t *pamh, uid_t uid,
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}
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}
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- if (fsync(*tfile)) {
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- pam_syslog(pamh, LOG_ALERT, "update (fsync) failed for %s: %m", filename);
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- return PAM_AUTH_ERR;
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- }
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return PAM_SUCCESS;
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}
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