Bug#725845: linux: cached file timestamp is rounded when cache expires (re-occurrence of bug 366940)

[Simon <grotlek@hotmail.com>]

Package: src:linux
Version: 3.10.11-1
Severity: normal
File: linux

Dear Maintainer,

It seems that a previously-fixed bug has crept back into the system.

Bug #366940 (which I can't re-open because it's archived) is occurring with my shiny Debian Jessie.
Direct Link: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=366940

Specifically this is causing problems with file editors, which believe the files have been externally modified,
and thus are popping up dialogues requesting the file be re-loaded from disk a couple of seconds after every
save. This, as you can imagine, becomes very irritating, very quickly.

I have researched and done my own "hacking" and have found two ways of preventing this bug occurring:

1) echo 1 > /proc/fs/cifs/LookupCacheEnabled
2) add "actimeo=0" to the mount flags

Here is my output showing the problem occur:

	root@linux-dev64:/mnt/simon# uname -a
	Linux linux-dev64 3.10-3-amd64 #1 SMP Debian 3.10.11-1 (2013-09-10) x86_64 GNU/Linux

	root@linux-dev64:/mnt/simon# echo 0 > /proc/fs/cifs/LookupCacheEnabled 
	root@linux-dev64:/mnt/simon# touch test.txt; ls -la --full-time test.txt; sleep 10; ls -la --full-time test.txt
	-rwxr-xr-x 1 simon simon 0 2013-10-09 01:50:38.000000000 +0100 test.txt
	-rwxr-xr-x 1 simon simon 0 2013-10-09 01:50:38.000000000 +0100 test.txt

	root@linux-dev64:/mnt/simon# echo 1 > /proc/fs/cifs/LookupCacheEnabled 
	root@linux-dev64:/mnt/simon# touch test.txt; ls -la --full-time test.txt; sleep 10; ls -la --full-time test.txt
	-rwxr-xr-x 1 simon simon 0 2013-10-09 01:51:02.515999388 +0100 test.txt
	-rwxr-xr-x 1 simon simon 0 2013-10-09 01:51:02.000000000 +0100 test.txt

As I said, this is just an annoyance to me, there's no data loss associated with it or anything that'd justify a high
priority; and I've got workarounds.

I'm just reporting that a supposedly-fixed bug is actually still occurring.

I've removed some of the more pointless information below (like what PCI devices I have etc). No point filling a bug report
with useless tat :-).



-- Package-specific info:
** Version:
Linux version 3.10-3-amd64 (debian-kernel@lists.debian.org) (gcc version 4.7.3 (Debian 4.7.3-7) ) #1 SMP Debian 3.10.11-1 (2013-09-10)

** Command line:
BOOT_IMAGE=/boot/vmlinuz-3.10-3-amd64 root=/dev/sda3 ro quiet

** Not tainted

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 3.10-3-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages linux-image-3.10-3-amd64 depends on:
ii  debconf [debconf-2.0]                   1.5.51
ii  initramfs-tools [linux-initramfs-tool]  0.113
ii  kmod                                    9-3
ii  linux-base                              3.5
ii  module-init-tools                       9-3

Versions of packages linux-image-3.10-3-amd64 recommends:
ii  firmware-linux-free  3.2

Versions of packages linux-image-3.10-3-amd64 suggests:
pn  debian-kernel-handbook  <none>
ii  grub-pc                 1.99-27+deb7u1
pn  linux-doc-3.10          <none>

Versions of packages linux-image-3.10-3-amd64 is related to:
pn  firmware-atheros        <none>
pn  firmware-bnx2           <none>
pn  firmware-bnx2x          <none>
pn  firmware-brcm80211      <none>
pn  firmware-intelwimax     <none>
pn  firmware-ipw2x00        <none>
pn  firmware-ivtv           <none>
pn  firmware-iwlwifi        <none>
pn  firmware-libertas       <none>
pn  firmware-linux          <none>
ii  firmware-linux-nonfree  0.40
pn  firmware-myricom        <none>
pn  firmware-netxen         <none>
pn  firmware-qlogic         <none>
pn  firmware-ralink         <none>
pn  firmware-realtek        <none>
pn  xen-hypervisor          <none>

-- debconf-show failed