smdb warp-around after 4 GB

[HeadTechnican at Mathco.com]

Unfortunately most users never see this problem due
to not many has files over 4 GB, actually files with size
over 700 MB is uncommon. Man this would meen my boss couln't
store his 11 GB video DV files on the server *sniff sniff*.

But I also feel that this needs to be researched.

Matt

> -----Original Message-----
> From: samba-admin at lists.samba.org [mailto:samba-admin at lists.samba.org]On
> Behalf Of Ivan Fernandez
> Sent: Thursday, November 08, 2001 8:42 AM
> To: Andreas Karrer; samba at lists.samba.org
> Subject: RE: smdb warp-around after 4 GB
> 
> 
> Hi Andreas,
> 
> 	I posted this very same problem a month ago, but no one could
> tell me any workaround. I also posted a level 10 log from the smbd
> daemon in the exact point of break. What I found there was that 1 smb
> packet before reaching 4 Gb. everything was ok, and the next smb packet
> reported a 0 byte and slowly growing corrupted file.
> 
> 	I hope someone will help this time, since using linux as a
> backup storage system is ideal. (What if a FIFO file redirected to bzip2
> is used to receive the backup stream?... but this is another war to
> fight..)
> 
> Cheers!
> 
> -----Mensaje original-----
> De: samba-admin at lists.samba.org [mailto:samba-admin at lists.samba.org]En
> nombre de Andreas Karrer
> Enviado el: lunes, 05 de noviembre de 2001 15:58
> Para: samba at lists.samba.org
> Asunto: smdb warp-around after 4 GB
> 
> 
> 
> I run Samba 2.2.2 on any of there vendors/osversions/filesystems:
> 
>   o Solaris 8 / ufs
>   o Tru64 Unix V5.0A / advfs
>   o RedHat 7.1 / Kernel 2.4.2 / ext2fs
> 
> all these are capable of handling large files (files with a
> 64-bit-offset larger than 4GB). At configure time, samba selects the
> proper compile flags (-D_LARGEFILE_SOURCE, -D_FILE_OFFSET_BITS=64)
> for use with large files.
> 
> The problem: When I back up a Win2000 machine using ntbackup onto a
>   file on a samba share, and the backup file is bigger than 4GB, the
>   backup is corrupted. This has also been reported by others in the
>   comp.protocols.smb newsgroup.
> 
> When I run tests using:
> 
>   smbclient //127.1/myshare
>   smb: \> put 4200MB 4200remote
> 
> where `4200MB' is a plain file of 4200 MB, the resulting file will
> be only a little bit bigger than 4GB. When I use "truss" or "strace"
> on the smbd server, near the 4GB limit I get:
> 
>         _llseek(19, 18446744073709406208, [4294821888], SEEK_SET) = 0
>         write(19, "UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"..., 64512) = 64512
>         _llseek(19, 18446744073709470720, [4294886400], SEEK_SET) = 0
>         write(19, "UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"..., 64512) = 64512
>   [1]   _llseek(19, 18446744073709535232, [4294950912], SEEK_SET) = 0
>   [2]   write(19, "UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"..., 64512) = 64512
>  ![3]   _llseek(19, 48128, [48128], SEEK_SET)   = 0
>         write(19, "UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"..., 64512) = 64512
>         _llseek(19, 112640, [112640], SEEK_SET) = 0
>         write(19, "UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU"..., 64512) = 64512
> 
>  [1] seek to (4GB - 16384 bytes)
>  [2] write 64512, offset now (4GB + 48128 bytes) = 4295015424
>  [3] seek to 48128 instead of (4GB + 48128 bytes) !!!!
> 
> This looks very much like a wrap-around of some offset variable that
> was declared `unsigned long' instead of `off_t'. By looking at the
> source, I cannot find an obvious point where this would happen, though.
> 
> 
> When I read a file from a samba server bigger than 4GB with something
> like:
> 
>   smbclient //127.1/myshare 
>   smb: \> get 4200MB 4200local
> 
> the file `4200local' grows without bounds. Using "truss", I find that
> there is a similar
> warp-around after 4 GB.
> 
> 
> Questions :
>   o Is smbd supposed to be large-file-proof, e.g. capable of handling
> files
>     larger than 4 GB?
>       *  On Solaris 8?
>       *  On Tru64 Unix?
>       *  On RedHat 7.1 / Kernel 2.4.2 / ext2?
> 
>   o Is smbclient supposed to be large-file-proof? (I see a few minor
>     problems in the source; the variables get_total_size,
>     put_total_size, nread in client/client.c should be declared
>     as off_t.
> 
>   o Am I missing something really obvious, such as a smb.conf file
> option?
> 
> 
> 
> 
> Regards,
> 
>  - Andi Karrer
> 
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