ls internal API works faster than smb_stat

[Puran Chand]

Hi all,

Raised a PR which addresses this.
https://github.com/samba-team/samba/pull/94

P.S notification script is broken hence sending the mail

On Wed, Feb 15, 2017 at 12:17 AM, Jeremy Allison <jra at samba.org> wrote:

> On Tue, Feb 14, 2017 at 11:11:10PM +0530, shravan a wrote:
> > Hi,
> >
> >
> > LibSmbClient exposes an api  *int **smbc_opendir*(*const* *char* *durl)
> which
> > accepts the parent folder path and fetches metadata about all its
> immediate
> > children and returns the directory handle to the parent folder. The api
> > *struct* smbc_dirent **smbc_readdir*(*unsigned* *int* dh) accepts this
> > directory handle(dh) and returns metadata as a structure (smbc_dirent)
> that
> > contains limited info such as smbc_type, dirlen, commentlen,comment,
> > namelen, name. Repetitive calls to this API fetches the next child
> metadata
> > in sequence and returns the structure. Unfortunately, it doesn’t give any
> > information regarding the resource size(important in case of files),
> > create/modified date time. To get these info, this library exposes two
> > API’s,
> >
> > *int* *smbc_stat*(*const* *char* *url, *struct* stat *st) - that accepts
> > the url and
> >
> > *int **smbc_fstat*(*int* fd, *struct* stat *st) that accepts the file
> > descriptor.
> >
> >      Both returns the required metadata as a structure ‘stat’ which
> > contains all the time stamps(create, modified, access) and the size.
> Both
> > needs to be invoked once for every child resource within the parent
> > resource. smbc_stat() is found to be an expensive task since it makes an
> > extra SMB call to the resource , while smbc_fstat() is found to be faster
> > since it accepts the file descriptor. But this still requires the file
> > descriptor which can be obtained only via another smbc_opendir(resource
> > url) or smbc_open(resource url).
> >
> >   Another API I tried out is –
> >
> > *Int **smbc_getxattr*(*const* *char* *fname,
> >
> >               *const* *char* *name,
> >
> >               *const* *void* *value,
> >
> >               size_t size)
> >
> >      This accepts the resourceurl, and the attribute name, returns the
> > attribute value. But this API also needs to be invoked once per child
> > resource within the parent folder which again is expensive.
> >
> >
> >
> > This extra API call for every child resource still makes the whole
> process
> > expensive.
> >
> >
> > However, when I open a smb session from the shell "ls" command performs
> > very fast. The function that "ls" internally calls in "list_dir".
> >
> > I would like to write a public API that would call the internal
> > implementation of "ls". Thoughts?
>
> What you need is readdirplus - a readdir that also returns
> stat info.
>
> Add a new call to libsmbclient called smbc_readdirplus().
>
> The internal call to cli_list gets most of the info you
> want (except for the EA values) so you will need to change
> the SMBC_opendir_ctx() function to use an internal callback
> that does more with the info returned by cli_list.
>
>


-- 

*RegardsPuran Chand*
*Member of Technical Staff*