SourceForge.net
2010-11-13 05:05:28 UTC
Bugs item #2010447, was opened at 2008-07-04 05:19
Message generated for change (Comment added) made by rogertsang
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=405834&aid=2010447&group_id=32541
Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Filesystem
Group: default
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: John Hughes (hughesj)
Initial Comment:
CFS doesn't keep the atime (last accessed time) field up to date.
This is a known limitation, I'm just reporting it here so it doesn't get forgotten about.
Maybe as a workaround we could pretend that cfs filesystems were mounted with the noatime option?
To reproduce:
$ cc tst-atime.c
$ ./a.out
atime has not changed
----------------------------------------------------------------------
Message:
Testing a patch. So far successfully tested at server.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-24 06:23
Message:
What's very bizarre is that this sometimes works on nodes other than the
one where the underlying filesystem is mounted, the access time seems to
get changed the first time a file is read, but not afterwards.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-19 12:04
Message:
Actually the:
rootfs / rootfs
stuff is not specific to OpenSSI.
What happens in statvfs is it looks for a mountpoint with the same
filesystem type as the file it's been given (so it's looking for ext2/ext3)
but from /proc our fs shows up as cfs, so it doesn't see that it's the same
one.
Later on it retries without the type, but this time around the "rootfs /
rootfs" one matches and that doesn't have the flags.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-19 11:32
Message:
Simple idea, just do this at user level by remounting the fs with an
explicit noatime option:
mount -o remount,noatime /
doesn't work because statvfs reads /proc/mounts to find the mount options
and some of the weird crud we have hanging around confuses it:
# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev2/root2 / cfs rw,noatime,chard,node=1 0 0
...
Which is the real root? Apparently statvfs thinks it's the first one.
----------------------------------------------------------------------
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=405834&aid=2010447&group_id=32541
Message generated for change (Comment added) made by rogertsang
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=405834&aid=2010447&group_id=32541
Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Filesystem
Group: default
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: John Hughes (hughesj)
Assigned to: Roger Tsang (rogertsang)
Summary: OpenSSI fails the glibc tst-atime testInitial Comment:
CFS doesn't keep the atime (last accessed time) field up to date.
This is a known limitation, I'm just reporting it here so it doesn't get forgotten about.
Maybe as a workaround we could pretend that cfs filesystems were mounted with the noatime option?
To reproduce:
$ cc tst-atime.c
$ ./a.out
atime has not changed
----------------------------------------------------------------------
Comment By: Roger Tsang (rogertsang)
Date: 2010-11-13 00:05Message:
Testing a patch. So far successfully tested at server.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-24 06:23
Message:
What's very bizarre is that this sometimes works on nodes other than the
one where the underlying filesystem is mounted, the access time seems to
get changed the first time a file is read, but not afterwards.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-19 12:04
Message:
Actually the:
rootfs / rootfs
stuff is not specific to OpenSSI.
What happens in statvfs is it looks for a mountpoint with the same
filesystem type as the file it's been given (so it's looking for ext2/ext3)
but from /proc our fs shows up as cfs, so it doesn't see that it's the same
one.
Later on it retries without the type, but this time around the "rootfs /
rootfs" one matches and that doesn't have the flags.
----------------------------------------------------------------------
Comment By: John Hughes (hughesj)
Date: 2008-10-19 11:32
Message:
Simple idea, just do this at user level by remounting the fs with an
explicit noatime option:
mount -o remount,noatime /
doesn't work because statvfs reads /proc/mounts to find the mount options
and some of the weird crud we have hanging around confuses it:
# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev2/root2 / cfs rw,noatime,chard,node=1 0 0
...
Which is the real root? Apparently statvfs thinks it's the first one.
----------------------------------------------------------------------
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=405834&aid=2010447&group_id=32541