[Samba] Re: Re: File changed as we read it.....

Tue Dec 10 18:13:01 GMT 2002

Well, the silence towards my issue with the mtime thing was starting to make
me thing I was going about things all wrong or something, so I decided to
try smbtar. It is a script that wraps the smbclient connection and tar
command available within an smbclient session.

The first thing I checked was the timestamp reported in an smbclient
session, it was the 58 seconds timestamp that ls and a second or later stat
reports for the file via an smbfs mount instead of the 57 seconds timestamp
that windows, tar's first scan, and the first stat of a day report. The
smbclient tar command ran on the file without any complaints.

Using this tar does give me the ability to do 'windows style' incremental
backups, based on the state of the archive bit (set/checked = back me up,
I've been changed) bit. I dont see a verify option for the smbclient tar
(v2.2.7) which I will miss. I was also trying to work with the GNU tar
listed incremental option, but again perhapse I should just use the archive
bit. When in Rome...

Still, if someone knowledgeable with and working on the smbfs code (or
wherever the mtime code is) would look into the mtime drift, I'd appreciate
it. I have more details in my post from 5 Dec 2002: Re: SMBFS files
receiving incorrect timestamps

Jacob

<daveman at bellatlantic.net> wrote in message
news:20021206222744.GB5883 at bellatlantic.net...
> On Fri, Dec 06, 2002 at 10:11:37AM -0700, Jacob Anawalt wrote:
> > (I have sent this to dpsims at virtualdave.com as well)
> >
> > David,
> >
> > I'm dealing with the same thing. I just posted yesterday asking about
it.
> > I'll put the contents of my post here, but a quick summary of what I
found
> > is that sometimes the mtime reports itself as one value and sometimes as
> > another value for a few of the files I access. For whatever reason tar
is
> > getting the right value when it starts making the archive, but as it
reads
> > the file it sees that smbfs is reporting a new time (in my case the new
> > mtime was one second later than the correct mtime.) Hopefully someone
will
> > have an answer for one of our posts.
> > The error isn't critical, which is why tar finishes the archive and
gives an
> > exit delayed message, but it is frustrating because I don't know without
> > investigating if it is a file that hasn't been modified for months, or
if
> > some program realy did change the contents of the file as I was tarring
it.
> > Even if a program did though, I believe you get the copy of the file as
it
> > was before the mtime changed.
> I am having this exact same problem, doing the exact same thing: backups.
I simply assumed that it was just quirky, but it would be nice to be able to
fix this. Very interested in hearing what you find out...
>
> --David
>
> > Ps. I access the newsgroup using gmane.org (news.gmane.org :
> > gmane.network.samba.general). It's a nice way to read the posts you want
> > without getting tons of email all day like you do with a mailing list.
> >
> > "David Sims" <dpsims at virtualdave.com> wrote in message
> > news:Pine.LNX.4.21.0212060443490.2621-100000 at ernie.virtualdave.com...
> >
> > > Hi,
> > >
> > > This is probably a newbie question, but here goes. I am using samba
> > > to mount some windows box's hard drives to a linux box for the purpose
> > > of doing backups on the windows boxes. This is done late at night and
> > > I am SURE that no one is using the windows boxes....
> > >
> > > While backing up I often see tar complain as
> > > follows: "tar: IssRating/C4dll.dll: file changed as we read it" or
> > > "tar: MPLUTIL/AUTO/TXOLD/AUTOMENU.EXE: file changed as we read it"
> > >
> > >
> > > What is causing these files to change??? Why would an executable or a
> > > dll change???
> > >
> > > Please reply via e-mail as I am not a list subscriber.
> > >
> > > Tia.
> > >
> > > Dave
> > >
> > > --
> > > To unsubscribe from this list go to the following URL and read the
> > > instructions: http://lists.samba.org/mailman/listinfo/samba
> > >
> >
> > My Post:  Re: SMBFS files receiving incorrect timestamps (Dec 5 2002)
> >
> > Hi,
> >
> > My tar (GNU tar) 1.13.25 on a RedHat 7.3 Linux system has been giving me
non
> > fatal, but discouraging messages for some time now as I try to archive
files
> > across smb mounts to a Windows 2000 Server system. it doesn't happen
with
> > all files, fortunatly, but it does happen with a few files per archive.
> >
> > tar: <filename>: file changed as we read it
> >
> > The strange thing was when I would look at the files the mtime (on
either
> > system) was several months old. Today I dug deeper because I am
increasing
> > the number of files that I am backing up across the smb mounts.
> >
> > What I found was that without fail, tar would get one mtime value when
it
> > started reading the file, but that time must have drifted while reading
the
> > file, hence the message.
> >
> > mtime tar puts into the archive: (no matter how many times I run tar)
> > 2002-01-30 13:41:57
> > This is the same value reported by the file properties on the Windows 2k
> > server.
> >
> > mtime ls -l --full-time reports
> > Wed Jan 30 13:41:58 2002
> >
> > The first time I ran stat (after tarring the file a few times) it
reported:
> > Wed Jan 30 13:41:57 2002
> > I ran it again, immediatly after that output, and it reported:
> > Wed Jan 30 13:41:58 2002
> >
> > stat continues to report this value no matter even after running tar
again,
> > which continues to put the (correct) Wed Jan 30 13:41:57 2002 value into
the
> > archive
> >
> > When I copied (cp -a) the file from the smb mount to the local ext3 fs,
the
> > mtime was Wed Jan 30 13:41:58 2002 (incorrect)
> >
> > Now, one second isn't any big deal except that tar sees it as a change
and
> > then I have to track down and see if tar realy got the right version of
the
> > file(s) (maybe the file wasn't months old).
> >
> > I have tried remounting, and that didn't help.
> >
> > Other program versions:
> > kernel 2.4.18-3
> > samba 2.2.7-1.7.3
> > stat: 2.5-5
> > ls (GNU fileutils) 4.1
> > mount 2.11n-12.7.3
> >
> > I found this thread in the archives in October 2002, and it seems
slightly
> > related. I gather from the reply that smbfs is actualy managing the
mtime
> > values instead of passing on what it reads from the remote file system?
If
> > so, is there one library call (the one tar uses for the archive headers)
> > that returns the right mtime, and another (the one tar uses to see the
file
> > has changed and that ls -l uses) that returns the wrong mtime? More
likely
> > by some wierd twist tar always gets smbfs to report the right time at
first
> > but then as the file is accessed (read by tar, ls) smbfs is then
reporting
> > the wrong mtime?
> >
> > Any suggested work-arounds in configuration settings are appreciated.
Maybe
> > when someone is going over the timestamp code, they might use this
> > information to fix the glitch (if it is in the smbfs/smb mount)
> >
> > Jacob Anawalt
> >
> > On Mon, 28 Oct 2002, Urban Widmark wrote:
> > smbfs sets the mtimes itself. Not really sure why it was done like that,
but
> > some comments claim that NT4 doesn't set mtime properly otherwise. It
would
> > be better to just let the server handle time.
> > The 1-hour diff is probably the daylight savings change. smbfs is told
by
> > smbmount what the server timezone is, as minutes from GMT. Of course
this
> > changes with the daylight savings ...
> > On Mon, 28 Oct 2002, Kris Kelley wrote:
> > Hello all.
> > Our system consists of two linux machines, each running Red Hat 7.1
(kernel
> > 2.4.9-34), using SMB to mount multiple shares hosted by a Windows 2000
> > Advance Server. smbclient from Samba 2.2.5 is used to do the actual
> > mounting.
> > Over the weekend, a number of files on these SMBFS shares were created
with
> > incorrect timestamps (modification times). In some cases, the timestamps
> > were off by as much as four days! Today, every file created by the linux
> > machines, even those created by "touch" called without any extra
arguments,
> > received timestamps that were one hour ahead.
> > When I discovered this was happening, I unmounted all SMBFS shares, and
> > remounted them. This fixed the problem; all files created now have the
> > correct timestamp.
> > The Windows host and the linux clients all have their system clocks set
> > correctly, and their system clocks were updated automatically during the
> > switch from daylight savings time. I suspect the 1-hour discrepancy I
saw
> > today has something to do with the daylight savings switch, but if that
is
> > the case, what caused some files created on Saturday (26
> > October) to receive timestamps for this coming Wednesday (30 October)?
> > Most importantly, how do I keep this from happening again? Please let me
> > know if more information is needed. Thank you.
> > ---Kris Kelley
> >
> >
> >
> > --
> > To unsubscribe from this list go to the following URL and read the
> > instructions: http://lists.samba.org/mailman/listinfo/samba
> >
> >
> >
> >
> > --
> > To unsubscribe from this list go to the following URL and read the
> > instructions:  http://lists.samba.org/mailman/listinfo/samba
>
> --
>  |\_/|
>  (\ /)
>   ) (//^\
>  ( M )
> (_)_(_)
> --
> To unsubscribe from this list go to the following URL and read the
> instructions:  http://lists.samba.org/mailman/listinfo/samba
>