The patch titled
Subject: autofs: update autofs.txt for strictexpire mount option
has been added to the -mm tree. Its filename is
autofs-update-autofstxt-for-strictexpire-mount-option.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/autofs-update-autofstxt-for-strictexpire-mount-option.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/autofs-update-autofstxt-for-strictexpire-mount-option.patch
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------------------------------------------------------
From: Ian Kent <raven@xxxxxxxxxx>
Subject: autofs: update autofs.txt for strictexpire mount option
A "strictexpire" mount option has been added to the autofs file system.
It is meant to be used in cases where a GUI continually accesses or an
application frquently scans an automount directory tree causing an
accumulation of otherwise unused mounts.
Link: http://lkml.kernel.org/r/155287083000.12593.2722713092537666885.stgit@xxxxxxxxxxxxxxxx
Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/autofs.txt | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/Documentation/filesystems/autofs.txt~autofs-update-autofstxt-for-strictexpire-mount-option
+++ a/Documentation/filesystems/autofs.txt
@@ -240,11 +240,18 @@ Normally the daemon only wants to remove
used for a while. For this purpose autofs maintains a "`last_used`"
time stamp on each directory or symlink. For symlinks it genuinely
does record the last time the symlink was "used" or followed to find
-out where it points to. For directories the field is a slight
-misnomer. It actually records the last time that autofs checked if
-the directory or one of its descendants was busy and found that it
-was. This is just as useful and doesn't require updating the field so
-often.
+out where it points to. For directories the field is used slightly
+differently. The field is updated at mount time and during expire
+checks if it is found to be in use (ie. open file descriptor or
+process working directory) and during path walks. The update done
+during path walks prevents frequent expire and immediate mount of
+frequently accessed automounts. But in the case where a GUI continually
+access or an application frequently scans an autofs directory tree
+there can be an accumulation of mounts that aren't actually being
+used. To cater for this case the "`strictexpire`" autofs mount option
+can be used to avoid the "`last_used`" update on path walk thereby
+preventing this apparent inability to expire mounts that aren't
+really in use.
The daemon is able to ask autofs if anything is due to be expired,
using an `ioctl` as discussed later. For a *direct* mount, autofs
_
Patches currently in -mm which might be from raven@xxxxxxxxxx are
autofs-fix-some-word-usage-odities-in-autofstxt.patch
autofs-update-autofstxt-for-strictexpire-mount-option.patch
autofs-update-autofs_exp_leaves-description.patch
autofs-update-mount-control-expire-desription-with-autofs_exp_forced.patch
autofs-add-description-of-ignore-pseudo-mount-option.patch
