Samba performance issues: stat calls

[Steve Langasek]

On Fri, Apr 04, 2003 at 10:19:57AM -0800, Richard Sharpe wrote:
> On Fri, 4 Apr 2003, Simo Sorce wrote:

> > On Fri, 2003-04-04 at 19:53, Richard Sharpe wrote:
> > > On Fri, 4 Apr 2003, Andrew Bartlett wrote:
> > > 
> > > > On Thu, 2003-04-03 at 18:06, Michael B.Allen wrote:
> > > > > On Wed, 2 Apr 2003 19:26:36 -0800 (PST)
> > > > > Richard Sharpe <rsharpe at richardsharpe.com> wrote:
> > > > > 
> > > > > > That looks like an average of more than one stat call per SMB. Not good!
> > > > > 
> > > > > Don't you have to stat each label in a path as you walk it?
> > > > 
> > > > Yes, given how Samba works, one stat per smb is actually pretty low...
> > > 
> > > Well, stat just hit number 1 problem for me :-)
> > > 
> > > I have got to look at converting it to an IOCTL in our case, because our 
> > > file system keeps times a 64-bit quantities, but POSIX is so aweful that 
> > > we have to convert them to 32-bits in our POSIX subsystem and then back to 
> > > 64-bits in Samba.

> > even in 64bit systems??

> The standard POSIX stat call returns 32-bit times, I believe.

On my 64-bit Linux systems, I have:

struct stat
{ 
    [...]
    __time_t st_atime;          /* Time of last access.  */
    __time_t st_mtime;          /* Time of last modification.  */
    __time_t st_ctime;          /* Time of last status change.  */
    [...]
}

AFAIK (and I don't have a copy of the spec handy to confirm -- just
manpage references), POSIX only defines that these members should be
'time_t', it does not define the size of time_t itself.  I see __time_t
defined here as a 'long int', which makes it 64-bit on 64-bit
architectures.

So I don't think your hands are tied by POSIX zipties here, though of
course changing the size of a member of a published structure is
difficult in its own right.

-- 
Steve Langasek
postmodern programmer
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