samba - Oct 2006 - open(2) O_DIRECT on smbmount gives EINVAL

Does samba 3.0.23c not support the use of O_DIRECT?  When I try to open an 
smbmount'd file using O_DIRECT, I get EINVAL.  I am able to use O_DIRECT
with no
problems on a block device and nfs mounts, so I know the kernel supports it.

samba:  3.0.23c
kernel: 2.6.9-42.0.3.EL (32-bit)

I am using the below code for my test.  smb fails on open(2).

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <stdint.h>

#define SECTORSIZE 512

#define ALIGN_NUM(val, mult) (((val) + ((mult) - 1)) & ~(((mult) - 1)))
#define ALIGN_PTR(ptr, mult) (void *)ALIGN_NUM((uintptr_t)(ptr), mult)

#define DECL_ALIGNED_BUFFER(name, size) \
   char __##name[(size) + SECTORSIZE]; \
   char *name = (char *)ALIGN_PTR(__##name, SECTORSIZE)

#define TEST_FILE "test.txt"

int main(void)
{
   int fd;
   int len = SECTORSIZE;
   DECL_ALIGNED_BUFFER(buf, len);

   unlink(TEST_FILE);
   errno = 0;

   // smb fails here
   fd = open(TEST_FILE, O_WRONLY|O_CREAT|O_EXCL|O_DIRECT, 0777);
   if(fd == -1)
   {
     perror("open");
     return 1;
   }

   memset(buf, ' ', len);
   memcpy(buf, "hello\n", 6);

   if(write(fd, buf, len) == -1)
   {
     perror("write");
     close(fd);
     return 1;
   }

   close(fd);
   printf("success\n");
   return 0;
}


thanks

On Sat, Oct 14, 2006 at 09:32:05PM -0400, tupple wrote:
> Does samba 3.0.23c not support the use of O_DIRECT?  When I try to open an 
> smbmount'd file using O_DIRECT, I get EINVAL.  I am able to use
O_DIRECT
> with no problems on a block device and nfs mounts, so I know the kernel 
> supports it.
Are you using smbfs or cifsfs ? It isn't the Samba
server side that doesn't support the O_DIRECT, this
is a client side option. I would imagine cifsfs
supports this.

Jeremy.

>>not in the server.
I am aware that we are talking about a client mount and not a samba server.  Did
I post to the wrong list?  Is this for samba server questions?  That is the 
second time you mentioned the server although I never mentioned it?  Actually in
my setup, there is no samba server.  There is a win2k box and a linux box.  I am
trying to do directio from the linux box to the win2k box through a smb or cifs 
mount.

My goal is to have the metadata and data flushed out of the linux machine after 
each write/fs_transaction.  Whether the target machine on the network, in this 
case a win2k box, actually flushes that to disk, is not a requirement.  My only 
requirement is that the smb or cifs mount on the linux box does not buffer 
anything: reads, writes, find_files, mkdirs, etc...  Everything is flushed out 
to the target.

With that in mind, does the mount.cifs "directio" option meet this
requirement.
  Does the "directio" option behave/accomplish the same things as
open(2)'s
O_DIRECT or O_SYNC?  Is buffer alignment required when using mount.cifs's
directio?

thanks,
andrew

Jeremy Allison wrote:
> On Sat, Oct 14, 2006 at 11:20:57PM -0400, Andrew Chernow wrote:
>> I tried this but got the same results, EINVAL?
>>
>> mount.cifs //machine/share /cifstest \
>>   -o username=xxx,password=xxx,directio,rw,noperm,soft
>>
>> Is the samba client utils, like smbmount and mount.cifs, supposed to 
>> support O_DIRECT?  There is mention of it in release notes, mostly
samba4.
>> Wondering if I need a patch or something.
> 
> It's something that needs to be supported in the client
> redirector code I think, not in the server.
> 
> Jeremy.
> 
>

On Sun, Oct 15, 2006 at 07:59:40AM -0400, Andrew Chernow
wrote:
> >>not in the server.
> I am aware that we are talking about a client mount and not a samba server.
> Did I post to the wrong list?  Is this for samba server questions?  That is
> the second time you mentioned the server although I never mentioned it?  
Yes, this list is for Samba server questions.

There is a cifs client list for client questions.

Jeremy.