smbd keeps to change same permission 600 on smbpasswd if download lots of files

Jeremy Allison jra at samba.org
Fri Aug 15 12:10:42 MDT 2014


On Fri, Aug 15, 2014 at 04:53:53PM +0800, Jones wrote:
> Hello list,
> 
> Found a performance concern if download lots of files from linux box,
> with samba-4.0.5 and the 'passwd backend = smbpasswd'.
> 
> There are 1000 files in the linux box, each size is 5MB.
> If download these files from the linux box to my win7,
> smbd is heavily access the file smbpasswd.
> If upload these files from my win7 back to the linux box,
> smbd does not touch the file smbpasswd at all.
> 
> After digging further[1][2][3],
> found the smbd keeps to change permission on the smbpasswd to 600,
> even though it is already with mode 600,
> and this fchmod()/chmod() makes dirty.

This is probably a good thing to do (although I'd
only accept this if we have fchmod available, to prevent
race conditions).

But is there a reason you can't use a tdb passdb backend
instead ? That won't suffer from the same issue.

Jeremy.


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