Re: cifs large write performance improvements to Samba

[cliff white <cliffw@osdl.org>]

On Mon, 13 Dec 2004 10:56:45 -0600
Steve French <smfrench@austin.rr.com> wrote:

> The current mainline (very recent 2.6.10-rc Linux tree) should be fine 
> from memory leak perspective.  No such leaks have been reported AFAIK on 
> current cifs code and certainly none that I have detected in heavy 
> stress testing. 
> 
> I do need to add some additional filesystem tests to the regression test 
> mix soon, and I have asked one  of the guys here  with a ppc64 box to 
> run some more bigendian tests on it too.   The ltp has filesystems tests 
> scatterred in multiple directories which I need to track down and setup 
> scripts to automate (e.g. the sendfile tests are not in the same 
> directory with other tests in testcases/kernel/fs, nor is the very 
> useful "connectathon nfs" posix filesystem test suite)
> 
> The oops (referenced in your post) does need to be fixed of course, but 
> since the code that would cause it is disabled (and only is broken to 
> certain servers and is noted as broken in the TODO list, implying that 
> it should not be turned on in /proc/fs/cifs) - I was considering it 
> lower priority than the other issues recently fixed which have been 
> consuming my time.  Fixing/adding support for extended security is 
> getting closer to the top of the priority list now though.  If I can at 
> least prevent the oops with a small change (even if it does not fully 
> fix the spnego code) I will push that changeset in soon.   The userspace 
> piece should be -- much -- easier to communicate with now that the 
> kevents stuff is in.    Very high on the list as well is getting NTLMv2 
> tested and working as many environments require it.  Figuring out the 
> mysterious byte range lock failure which sometimes occurs on an unlock 
> in locktest 7 (I noticed it starting after the nfs changes for the vfs 
> posix locking a few months ago) and I have posted about before (Kernel 
> panic - not syncing: Attempting to free lock with active blocklist) is a 
> slightly higher priority.  Basically I need to figure out what is going 
> on with the line in fs/locks.c?
> 
>        if (!list_empty <http://lxr.linux.no/ident?v=2.6.8.1;i=list_empty>(&fl->fl_block)
> 		 panic <http://lxr.linux.no/ident?v=2.6.8.1;i=panic>(/"Attempting to free lock with active block list"/);
> 
> 
> Since I am not adding anything to the fl_block list intentionally, I 
> need to find out what causes items to be added to the fl_block list (ie 
> when the locks_insert_block and locks_delete_block call are made and why 
> they sometimes happen differently in lock test 7 then in other byte 
> range lock testcases in which unlock obviously works fine).
> 
> On the issue of regressing back to smbfs :)  There are a few things 
> which can be done that would help.
> 
> 1) Need to post an updated version of when to still use smbfs for an 
> occassional mount (there are only a couple of cases in which smbfs has 
> to be used now but they are important to some users - such as users who 
> have to access an occassional old OS/2 or DOS server, or who need 
> Kerberos), and I need to add it that chart to the fs/cifs/README and the 
> project page etc.
> 2) Public view of the status of testing - the raw data needs to be 
> posted regularly as kernel updated (and against five or six different 
> server types) so users see what is broken in smbfs (and so users can see 
> what posix issues are still being worked on cifs and any known 
> problems).   smbfs fails about half of the filesystem tests that I have 
> tried, due to stress issues, or because the tests requires better posix 
> compliance or because of various smbfs stability fixes.
> 
>   If only someone could roll all of the key fs tests into a set of 
> scripts which could generate one regularly updated set of test status 
> chart ... one for each of XFS, JFS, ext3, Reiser3, CIFS (against various 
> servers, Samba version etc), NFSv2, NFSv3, NFSv4 (against various 
> servers), AFS but that would be a lot of work (not to run) but the first 
> time writing/setup of the scripts to launch the tests in the right order 
> since some failures may be expected (at least for the network 
> filesystems) due to hard to implement features (missing fcntls, dnotify, 
> get/setlease, differences in byte range lock semantics, lack of flock 
> etc.) and also since the most sensible NFS, AFS and CIFS tests would 
> involve more than one client (to test caching/oplock/token management 
> semantics better) but no such fs tests AFAIK exist for Linux.

We ( OSDL ) would be very interested in this sort of testing. We have some fs tests
wrappered currently
cliffw
OSDL
> 
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