[linux-cifs-client] tail -f /mounted/share/filename is not working

[Suresh Jayaraman]

� wrote:
> Hi Steve, Jeff,
> 
> this one is on my todo list for more than a year now.

May be this behavior has changed now?  I tried to reproduce this on
2.6.27.19 with directio option against a Samba-3.0.26 server. I could
not reproduce this at all (I used tail instead of statgk). I'm
seeing the stuff written with negligible delay on the client.

Are you able to reproduce this with the recent kernels? If yes, are you
getting more clues as to what is happening with a tcpdump/cifsFYI ?

> 
> How to test:
>   server side: use "./wrt filename" or "./wrt -s 100 filename"
>                to start writing/appending to a file on a (samba) exported share
>                (regarding the '-s' option, I though writing large data would/could
>                 trigger some cifs "re-read server" internals (page dirty...))
>   cifs client side: (one might use 'tail -f /mnt/xyz/filename' as well)
>                     use ./statgk /mnt/xyz/filename
> 
> On the cifs client side "statgk" uses fstat() to get possible _updated_
> file info from the server (filesize, times, ...) - cifs *realizes* (!) the size (times) change,
> but no "read additional data" from the server is done.
> 

Thanks,

-- 
Suresh Jayaraman