samba - May 2010 - extra readdir operation when writing to a non-existent file

hi samba fellows,

It is my first time to ask questions in samba mail list. Very sorry if
my question is very naive.

The problem is when I write to
a non-existent file from windows to a linux export, there will be an
extra readdir operation triggered. If I write to an existent file, no
readdir operation will be triggered.

How could I avoid the extra readdir operation in all cases when I am just
writing to a file?

Very much appreciate your help!

I used samba
(3.4.0) to export a FUSE mount from Ubuntu with the following smb.cnf:

----------------------------------------------------------------
[global]
  security = share
  guest account = nobody

[mofs]
  path = /mnt/mofs
  public = yes
  guest ok = yes
  guest only = yes
  guest account = nobody
  writeable = yes
  browseable = yes
----------------------------------------------------------------

On 12/05/10 10:16, Zhang Bingjun (Eddy) wrote:
> hi samba fellows,
> 
> It is my first time to ask questions in samba mail list. Very sorry if
> my question is very naive.
> 
> The problem is when I write to
> a non-existent file from windows to a linux export, there will be an
> extra readdir operation triggered. If I write to an existent file, no
> readdir operation will be triggered.
I'm still pretty knew on this list too, but let me take a guess about
what may be going on:

Windows (by default) is case-insensitive, Unix is case-sensitive. So, if
you write to a non existant file (let's call it "test.txt"), the
kernel
will tell samba that the file "test.txt" doesn't exist. However,
there
could be a file called "Test.txt" or "TEST.TXT", ... The
open call won't
tell that, the only way for samba to find out is to do a readdir and
manually go through the list to see whether anything matches in a
case-insensitive way.
> 
> How could I avoid the extra readdir operation in all cases when I am just
> writing to a file?
Switching samba to a case-sensitive mode might help, try putting the
following into your smb.conf:

case sensitive = yes


if that alone doesn't help, you might try setting all 4 of the following:

default case = lower
sensitive = yes
preserve case = no
short preserve case = No

Indeed, the smb.conf says the following:

default case = upper/lower
    controls what the default case is for new filenames (ie. files that
    don?t currently exist in the filesystem). Default lower. IMPORTANT
    NOTE: This option will be used to modify the case of all incoming
    client filenames, not just new filenames if the options case
    sensitive = yes, preserve case = No, short preserve case = No are
    set. This change is needed as part of the optimisations for
    directories containing large numbers of files.
> 
> Very much appreciate your help!
Regards,

Alain

On 12/05/10 10:16, Zhang Bingjun (Eddy) wrote:
> hi samba fellows,
> 
> It is my first time to ask questions in samba mail list. Very sorry if
> my question is very naive.
> 
> The problem is when I write to
> a non-existent file from windows to a linux export, there will be an
> extra readdir operation triggered. If I write to an existent file, no
> readdir operation will be triggered.
I'm still pretty knew on this list too, but let me take a guess about
what may be going on:

Windows (by default) is case-insensitive, Unix is case-sensitive. So, if
you write to a non existant file (let's call it "test.txt"), the
kernel
will tell samba that the file "test.txt" doesn't exist. However,
there
could be a file called "Test.txt" or "TEST.TXT", ... The
open call won't
tell that, the only way for samba to find out is to do a readdir and
manually go through the list to see whether anything matches in a
case-insensitive way.
> 
> How could I avoid the extra readdir operation in all cases when I am just
> writing to a file?
Switching samba to a case-sensitive mode might help, try putting the
following into your smb.conf:

case sensitive = yes


if that alone doesn't help, you might try setting all 4 of the following:

default case = lower
sensitive = yes
preserve case = no
short preserve case = No

Indeed, the smb.conf says the following:

default case = upper/lower
    controls what the default case is for new filenames (ie. files that
    don?t currently exist in the filesystem). Default lower. IMPORTANT
    NOTE: This option will be used to modify the case of all incoming
    client filenames, not just new filenames if the options case
    sensitive = yes, preserve case = No, short preserve case = No are
    set. This change is needed as part of the optimisations for
    directories containing large numbers of files.
> 
> Very much appreciate your help!
Regards,

Alain

Hi Alain,

Your suggestion works. Thank you very much!

Best regards,
Zhang Bingjun, Eddy



On Wed, May 12, 2010 at 4:33 PM, Alain Knaff <alain at knaff.lu> wrote:
> On 12/05/10 10:16, Zhang Bingjun (Eddy) wrote:
> > hi samba fellows,
> >
> > It is my first time to ask questions in samba mail list. Very sorry if
> > my question is very naive.
> >
> > The problem is when I write to
> > a non-existent file from windows to a linux export, there will be an
> > extra readdir operation triggered. If I write to an existent file, no
> > readdir operation will be triggered.
>
> I'm still pretty knew on this list too, but let me take a guess about
> what may be going on:
>
> Windows (by default) is case-insensitive, Unix is case-sensitive. So, if
> you write to a non existant file (let's call it "test.txt"),
the kernel
> will tell samba that the file "test.txt" doesn't exist.
However, there
> could be a file called "Test.txt" or "TEST.TXT", ...
The open call won't
> tell that, the only way for samba to find out is to do a readdir and
> manually go through the list to see whether anything matches in a
> case-insensitive way.
>
> >
> > How could I avoid the extra readdir operation in all cases when I am
just
> > writing to a file?
>
> Switching samba to a case-sensitive mode might help, try putting the
> following into your smb.conf:
>
> case sensitive = yes
>
>
> if that alone doesn't help, you might try setting all 4 of the
following:
>
> default case = lower
> sensitive = yes
> preserve case = no
> short preserve case = No
>
> Indeed, the smb.conf says the following:
>
> default case = upper/lower
>    controls what the default case is for new filenames (ie. files that
>    don?t currently exist in the filesystem). Default lower. IMPORTANT
>    NOTE: This option will be used to modify the case of all incoming
>    client filenames, not just new filenames if the options case
>    sensitive = yes, preserve case = No, short preserve case = No are
>    set. This change is needed as part of the optimisations for
>    directories containing large numbers of files.
>
> >
> > Very much appreciate your help!
>
> Regards,
>
> Alain
>