Re: Directory Leases

[Ralph Boehme <slow@samba.org>]

Hi Steve,

On 10/28/24 10:11 PM, Steve French wrote:
> Doing some additional experiments to Windows and also to the updated
> Samba branch from Ralph, I see the directory lease request, and
> I see that after ls (which will cache the directory contents for about
> 30 second) we do get a big benefit from the metadata of the directory
> entries being cached e.g. "ls /mnt ; sleep 10; stat /mnt/file ; sleep
> 15 stat /mnt/file2 ; sleep 10 /mnt/file"  - we only get the roundtrips
> for the initial ls - the stat calls don't cause any network traffic
> since the directory is cached.
indeed, I can confirm that some cache is used for stat. Unfortunately it 
isn't used for readddir.

Also, coming back on the issue that the client is deferring a close on 
the directory with having a H lease:

In my understanding that's at least going to cause problems if other 
clients want to do anything on the server that is not allowed if there 
are conflicting opens like renaming a directory (which is not allowed if 
there are any opens below recursively). Unlinks will also be deferred as 
long as the client sticks to its handle.

The client should acquire a RH lease on directories if it wants to cache 
the handle and that's a prerequisite in order to cache readdir.

Afair the kernel is currently caching for 30 seconds. Increasing this 
time should not be done without also having a H lease.

-slow