[Ocfs2-devel] [RFC] [PATCH] OCFS2

[Ocfs2-devel] [RFC] [PATCH] OCFS2

[Mark Fasheh]

Hello,

This is OCFS2, a shared disk cluster file system which we hope will be
included in the kernel.

We think OCFS2 has many qualities which make it particularly
interesting as a cluster file system:

-We've tried very hard to avoid the abstraction layers which tend to
 plague other cluster file systems. Wherever possible, OCFS2 sits directly
 atop the VFS. Journaling is done via JBD, including node recovery.

-Though OCFS2 is an extent based file system, much of the disk layout
 design has been taken from Ext3. As mentioned before, journal formats
 are JBD. Though OCFS2 does not yet support htree, directory data
 looks nearly identical to that of Ext3, with the exception that OCFS2
 inode numbers are 64 bits wide. Data and meta data are allocated from
 dynamically growable "chain allocators" whose chain items look very
 similar to block groups.

-OCFS2 has a strong data locking model, which includes a shared mmap
 implementation (shared writeable mappings are not yet supported) and
 full AIO support.

-OCFS2 has a very low overhead direct I/O path.

Within the file system, the cluster stack below us has been abstracted
out as much as possible:

-Heartbeat events are delivered to us via a simple callback mechanism.

-File system network communication has only minimal knowledge of node
 information.

-File system cluster locking, including lock caching, is handled
 through a "dlm glue" layer which abstracts away the actual dlm
 implementation beneath (though it assumes a VMS-like API with a
 minimal set of features).

Included in OCFS2 is a small cluster stack. It should be noted that we
do *not* propose this as a generic cluster stack. While we hope the
cluster stack can be useful to other projects it was certainly
implemented with only the requirements of a cluster file system in
mind. Looking towards the future, we would like to either extend this
stack to be more generic or plug in a more generic stack - assuming it
gives us similar ease of use and performance and has undergone the
appropriate community discussion. For now the cluster stack and dlm
components have been placed in their respective directories within the
"ocfs2" subdirectory.

A major goal in the design of OCFS2 was to make configuration of the
entire stack as painless as possible. There is only one configuration
file required which describes all nodes in an OCFS2 cluster
(/etc/ocfs2/cluster.conf). The cluster.conf file is the same for all
nodes so that it can be easily re-copied when changed.

Anyone wanting to use OCFS2 should download the tool chain from
http://oss.oracle.com/projects/ocfs2-tools/source.html The current
OCFS2-tools package includes a full set of standard file system
utilities (mkfs.ocfs2, fsck.ocfs2, mount.ocfs2, tunefs.ocfs2,
debugfs.ocfs). Pulling down the latest subversion tree is usually
best. Setup is quite simple, after software installation, either hand
create a configuration or use the "ocfs2console" program to generate
one for you.

Currently the code should be considered beta quality. The OCFS2 team
is deep in a cycle of bug fixing and performance evaluation. As a
proof of concept, we've been able to bring up a 12 node shared root
cluster.  Already, performance on the file system looks promising. A
parallel kernel build (make -j4 bzImage on each node within their own
trees) compares well with ext3:

        Ext3           OCFS2
node1   13m4s          13m16s
node2   10m27s         10m38s

In case there is any concern about code size, a quick comparison shows
the file system and cluster stacks combined size to be not
significantly larger than reiserfs and 1/3 the size of xfs.

For people using git, these changes can be pulled from:
http://oss.oracle.com/git/ocfs2.git/

A full patch can be downloaded from:
http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch

Broken out versions of the patches can be found at:
http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/

A short description of each patch follows. The same descriptions can be
found at the top of each patch file.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/01_configfs.patch
Configfs, a file system for userspace-driven kernel object configuration.
The OCFS2 stack makes extensive use of this for propagation of cluster
configuration information into kernel.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/02_mlog.patch
Very simple printk wrapper which adds the ability to enable various
sets of debug messages at run-time.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/03_nm.patch
A simple node information service, filled and updated from
userspace. The rest of the stack queries this service for simple node
information.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/04_heartbeat.patch
Disk based heartbeat. Configured and started from userspace, the
kernel component handles I/O submission and event generation via
callback mechanism.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/05_messaging.patch
Node messaging via tcp. Used by the dlm and the file system for point
to point communication between nodes.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/06_dlm.patch
A distributed lock manager built with the cluster file system use case
in mind. The OCFS2 dlm exposes a VMS style API, though things have
been simplified internally. The only lock levels implemented currently
are NLMODE, PRMODE and EXMODE.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/07_dlmfs.patch
dlmfs: A minimal dlm userspace interface implemented via a virtual
file system.
Most of the OCFS2 tools make use of this to take cluster locks when
doing operations on the file system.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/08_ocfs2.patch
The OCFS2 file system module.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/09_build.patch
Link the code into the kernel build system. OCFS2 is marked as
experimental and we only enable builds on x86, x86-64 and ia64 -
endianness consistency is a work in progress.

When built, the stack will result in 5 modules: configfs.ko,
ocfs2_nodemanager.ko, ocfs2_dlm.ko, ocfs2.ko and ocfs2_dlmfs.ko


--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Hans Reiser]

Mark Fasheh wrote:

>In case there is any concern about code size, a quick comparison shows
>the file system and cluster stacks combined size to be not
>significantly larger than reiserfs and 1/3 the size of xfs.
>
>  
>
I too am quick to cite XFS when anyone complains about the code size of
anything we write.;-)

Congrats on getting a filesystem to start to work, I know how long that
road is, and  best of luck to you all,

Hans

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Adrian Bunk]

On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
>...
> A full patch can be downloaded from:
> http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
>...

Some comments on this patch:
- there's no reason to make JBD user-visible
- is there any reason why CONFIGFS_FS is user-visible?
- some global code might become static:
  run "make namespacecheck" after compiling the kernel and check
  the configfs and ocfs2 parts of the output

> Mark Fasheh

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Manish Singh]

On Thu, May 19, 2005 at 01:40:22AM +0200, Adrian Bunk wrote:
> On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
> >...
> > A full patch can be downloaded from:
> > http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
> >...
> 
> Some comments on this patch:
> - there's no reason to make JBD user-visible

Sure, the only reason I made it visible was because of the comment in
there:

# CONFIG_JBD could be its own option (even modular), but until there are
# other users than ext3, we will simply make it be the same as CONFIG_EXT3_FS

I don't really have a preference either way.

> - is there any reason why CONFIGFS_FS is user-visible?

It's a generic mechanism for userspace driven configuration of kernel
functionality. There's nothing specific to OCFS2 about it. Other kernel
subsystems/projects could use it too, for their own configuration
mechanisms. More details are in configfs.txt, which is included in the
above patch. Note the example used in the documentation text is an NBD
driver.

> - some global code might become static:
>   run "make namespacecheck" after compiling the kernel and check
>   the configfs and ocfs2 parts of the output

Yeah, there's some stuff that that scripts catches. Thanks.

-Manish

[RFC] [PATCH] OCFS2

[Mark Fasheh]

Hello,

This is OCFS2, a shared disk cluster file system which we hope will be
included in the kernel.

We think OCFS2 has many qualities which make it particularly
interesting as a cluster file system:

-We've tried very hard to avoid the abstraction layers which tend to
 plague other cluster file systems. Wherever possible, OCFS2 sits directly
 atop the VFS. Journaling is done via JBD, including node recovery.

-Though OCFS2 is an extent based file system, much of the disk layout
 design has been taken from Ext3. As mentioned before, journal formats
 are JBD. Though OCFS2 does not yet support htree, directory data
 looks nearly identical to that of Ext3, with the exception that OCFS2
 inode numbers are 64 bits wide. Data and meta data are allocated from
 dynamically growable "chain allocators" whose chain items look very
 similar to block groups.

-OCFS2 has a strong data locking model, which includes a shared mmap
 implementation (shared writeable mappings are not yet supported) and
 full AIO support.

-OCFS2 has a very low overhead direct I/O path.

Within the file system, the cluster stack below us has been abstracted
out as much as possible:

-Heartbeat events are delivered to us via a simple callback mechanism.

-File system network communication has only minimal knowledge of node
 information.

-File system cluster locking, including lock caching, is handled
 through a "dlm glue" layer which abstracts away the actual dlm
 implementation beneath (though it assumes a VMS-like API with a
 minimal set of features).

Included in OCFS2 is a small cluster stack. It should be noted that we
do *not* propose this as a generic cluster stack. While we hope the
cluster stack can be useful to other projects it was certainly
implemented with only the requirements of a cluster file system in
mind. Looking towards the future, we would like to either extend this
stack to be more generic or plug in a more generic stack - assuming it
gives us similar ease of use and performance and has undergone the
appropriate community discussion. For now the cluster stack and dlm
components have been placed in their respective directories within the
"ocfs2" subdirectory.

A major goal in the design of OCFS2 was to make configuration of the
entire stack as painless as possible. There is only one configuration
file required which describes all nodes in an OCFS2 cluster
(/etc/ocfs2/cluster.conf). The cluster.conf file is the same for all
nodes so that it can be easily re-copied when changed.

Anyone wanting to use OCFS2 should download the tool chain from
http://oss.oracle.com/projects/ocfs2-tools/source.html The current
OCFS2-tools package includes a full set of standard file system
utilities (mkfs.ocfs2, fsck.ocfs2, mount.ocfs2, tunefs.ocfs2,
debugfs.ocfs). Pulling down the latest subversion tree is usually
best. Setup is quite simple, after software installation, either hand
create a configuration or use the "ocfs2console" program to generate
one for you.

Currently the code should be considered beta quality. The OCFS2 team
is deep in a cycle of bug fixing and performance evaluation. As a
proof of concept, we've been able to bring up a 12 node shared root
cluster.  Already, performance on the file system looks promising. A
parallel kernel build (make -j4 bzImage on each node within their own
trees) compares well with ext3:

        Ext3           OCFS2
node1   13m4s          13m16s
node2   10m27s         10m38s

In case there is any concern about code size, a quick comparison shows
the file system and cluster stacks combined size to be not
significantly larger than reiserfs and 1/3 the size of xfs.

For people using git, these changes can be pulled from:
http://oss.oracle.com/git/ocfs2.git/

A full patch can be downloaded from:
http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch

Broken out versions of the patches can be found at:
http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/

A short description of each patch follows. The same descriptions can be
found at the top of each patch file.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/01_configfs.patch
Configfs, a file system for userspace-driven kernel object configuration.
The OCFS2 stack makes extensive use of this for propagation of cluster
configuration information into kernel.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/02_mlog.patch
Very simple printk wrapper which adds the ability to enable various
sets of debug messages at run-time.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/03_nm.patch
A simple node information service, filled and updated from
userspace. The rest of the stack queries this service for simple node
information.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/04_heartbeat.patch
Disk based heartbeat. Configured and started from userspace, the
kernel component handles I/O submission and event generation via
callback mechanism.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/05_messaging.patch
Node messaging via tcp. Used by the dlm and the file system for point
to point communication between nodes.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/06_dlm.patch
A distributed lock manager built with the cluster file system use case
in mind. The OCFS2 dlm exposes a VMS style API, though things have
been simplified internally. The only lock levels implemented currently
are NLMODE, PRMODE and EXMODE.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/07_dlmfs.patch
dlmfs: A minimal dlm userspace interface implemented via a virtual
file system.
Most of the OCFS2 tools make use of this to take cluster locks when
doing operations on the file system.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/08_ocfs2.patch
The OCFS2 file system module.

http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-out/09_build.patch
Link the code into the kernel build system. OCFS2 is marked as
experimental and we only enable builds on x86, x86-64 and ia64 -
endianness consistency is a work in progress.

When built, the stack will result in 5 modules: configfs.ko,
ocfs2_nodemanager.ko, ocfs2_dlm.ko, ocfs2.ko and ocfs2_dlmfs.ko


--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Kyle Moffett]

On May 18, 2005, at 18:33:03, Mark Fasheh wrote:
> Hello,
>
> This is OCFS2, a shared disk cluster file system which we hope will be
> included in the kernel.
>
> We think OCFS2 has many qualities which make it particularly
> interesting as a cluster file system:

[...snip...]

> -OCFS2 has a strong data locking model, which includes a shared mmap
>  implementation (shared writeable mappings are not yet supported) and
>  full AIO support.

Does this include support for UNIX sockets and named pipes?  One of
the issues I have with filesystems like AFS and NFS is that they
should theoretically make such things possible, but the code is not
implemented yet and does not appear it ever will be.  This is very
useful for home directories when using programs like "links" that
rely on being able to create UNIX sockets in .links/socket or
similar.


Cheers,
Kyle Moffett

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCM/CS/IT/U d- s++: a18 C++++>$ UB/L/X/*++++(+)>$ P+++(++++)>$
L++++(+++) E W++(+) N+++(++) o? K? w--- O? M++ V? PS+() PE+(-) Y+
PGP+++ t+(+++) 5 X R? tv-(--) b++++(++) DI+ D+ G e->++++$ h!*()>++$  
r  !y?(-)
------END GEEK CODE BLOCK------

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Wed, May 18, 2005 at 10:30:56PM -0400, Kyle Moffett wrote:
> Does this include support for UNIX sockets and named pipes?
Unfortunately no, at least not on a clustered level. Local node, those
should work as normal. If you absolutely need this functionality, I believe
OpenSSI currently supports it.

If you're looking for an easy way to share small amounts data between
applications in an OCFS2 cluster, you might be interested in looking at
dlmfs. Once mounted, it's quite trivial to create dlm domains and lock
resources between nodes via regular file system operations (open, close,
etc). File read and write will return and set the resource LVB for you,
currently 64 bytes. Though this can all be controlled from shell, a small
library (libo2cb) to take advantage of this is provided in the current
toolchain distribution.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Hans Reiser]

Mark Fasheh wrote:

>In case there is any concern about code size, a quick comparison shows
>the file system and cluster stacks combined size to be not
>significantly larger than reiserfs and 1/3 the size of xfs.
>
>  
>
I too am quick to cite XFS when anyone complains about the code size of
anything we write.;-)

Congrats on getting a filesystem to start to work, I know how long that
road is, and  best of luck to you all,

Hans

Re: [RFC] [PATCH] OCFS2

[Adrian Bunk]

On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
>...
> A full patch can be downloaded from:
> http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
>...

Some comments on this patch:
- there's no reason to make JBD user-visible
- is there any reason why CONFIGFS_FS is user-visible?
- some global code might become static:
  run "make namespacecheck" after compiling the kernel and check
  the configfs and ocfs2 parts of the output

> Mark Fasheh

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Manish Singh]

On Thu, May 19, 2005 at 01:40:22AM +0200, Adrian Bunk wrote:
> On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
> >...
> > A full patch can be downloaded from:
> > http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
> >...
> 
> Some comments on this patch:
> - there's no reason to make JBD user-visible

Sure, the only reason I made it visible was because of the comment in
there:

# CONFIG_JBD could be its own option (even modular), but until there are
# other users than ext3, we will simply make it be the same as CONFIG_EXT3_FS

I don't really have a preference either way.

> - is there any reason why CONFIGFS_FS is user-visible?

It's a generic mechanism for userspace driven configuration of kernel
functionality. There's nothing specific to OCFS2 about it. Other kernel
subsystems/projects could use it too, for their own configuration
mechanisms. More details are in configfs.txt, which is included in the
above patch. Note the example used in the documentation text is an NBD
driver.

> - some global code might become static:
>   run "make namespacecheck" after compiling the kernel and check
>   the configfs and ocfs2 parts of the output

Yeah, there's some stuff that that scripts catches. Thanks.

-Manish

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Daniel Phillips]

On Wednesday 18 May 2005 18:33, Mark Fasheh wrote:
> http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-o
>ut/06_dlm.patch A distributed lock manager built with the cluster file
> system use case in mind. The OCFS2 dlm exposes a VMS style API, though
> things have been simplified internally. The only lock levels implemented
> currently are NLMODE, PRMODE and EXMODE.

+ if (recovery && 
+     (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
+  goto error;
+ }

Zero terminated strings for lock names is bad taste.  It generates a bunch of 
useless strlen executions and you force an ascii namespace for no apparent 
reason.  Add a 9th parameter, namelen, to the lock call maybe?

Regards,

Daniel 

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Thu, May 19, 2005 at 02:30:23AM -0400, Daniel Phillips wrote:
> Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> useless strlen executions and you force an ascii namespace for no apparent 
> reason.  Add a 9th parameter, namelen, to the lock call maybe?
Or perhaps pass in a qstr? Anyway I have to agree. That shouldn't be
difficult to fix up.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Kyle Moffett]

On May 18, 2005, at 18:33:03, Mark Fasheh wrote:
> Hello,
>
> This is OCFS2, a shared disk cluster file system which we hope will be
> included in the kernel.
>
> We think OCFS2 has many qualities which make it particularly
> interesting as a cluster file system:

[...snip...]

> -OCFS2 has a strong data locking model, which includes a shared mmap
>  implementation (shared writeable mappings are not yet supported) and
>  full AIO support.

Does this include support for UNIX sockets and named pipes?  One of
the issues I have with filesystems like AFS and NFS is that they
should theoretically make such things possible, but the code is not
implemented yet and does not appear it ever will be.  This is very
useful for home directories when using programs like "links" that
rely on being able to create UNIX sockets in .links/socket or
similar.


Cheers,
Kyle Moffett

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCM/CS/IT/U d- s++: a18 C++++>$ UB/L/X/*++++(+)>$ P+++(++++)>$
L++++(+++) E W++(+) N+++(++) o? K? w--- O? M++ V? PS+() PE+(-) Y+
PGP+++ t+(+++) 5 X R? tv-(--) b++++(++) DI+ D+ G e->++++$ h!*()>++$  
r  !y?(-)
------END GEEK CODE BLOCK------

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Wed, May 18, 2005 at 10:30:56PM -0400, Kyle Moffett wrote:
> Does this include support for UNIX sockets and named pipes?
Unfortunately no, at least not on a clustered level. Local node, those
should work as normal. If you absolutely need this functionality, I believe
OpenSSI currently supports it.

If you're looking for an easy way to share small amounts data between
applications in an OCFS2 cluster, you might be interested in looking at
dlmfs. Once mounted, it's quite trivial to create dlm domains and lock
resources between nodes via regular file system operations (open, close,
etc). File read and write will return and set the resource LVB for you,
currently 64 bytes. Though this can all be controlled from shell, a small
library (libo2cb) to take advantage of this is provided in the current
toolchain distribution.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Adrian Bunk]

On Wed, May 18, 2005 at 06:26:58PM -0700, Manish Singh wrote:
> On Thu, May 19, 2005 at 01:40:22AM +0200, Adrian Bunk wrote:
> > On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
> > >...
> > > A full patch can be downloaded from:
> > > http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
> > >...
> > 
> > Some comments on this patch:
> > - there's no reason to make JBD user-visible
> 
> Sure, the only reason I made it visible was because of the comment in
> there:
> 
> # CONFIG_JBD could be its own option (even modular), but until there are
> # other users than ext3, we will simply make it be the same as CONFIG_EXT3_FS
> 
> I don't really have a preference either way.

I'd say the comment is wrong.

> > - is there any reason why CONFIGFS_FS is user-visible?
> 
> It's a generic mechanism for userspace driven configuration of kernel
> functionality. There's nothing specific to OCFS2 about it. Other kernel
> subsystems/projects could use it too, for their own configuration
> mechanisms. More details are in configfs.txt, which is included in the
> above patch. Note the example used in the documentation text is an NBD
> driver.
>...

If other subsystems use it, they should select it.

> -Manish

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [RFC] [PATCH] OCFS2

[Daniel Phillips]

On Wednesday 18 May 2005 18:33, Mark Fasheh wrote:
> http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/broken-o
>ut/06_dlm.patch A distributed lock manager built with the cluster file
> system use case in mind. The OCFS2 dlm exposes a VMS style API, though
> things have been simplified internally. The only lock levels implemented
> currently are NLMODE, PRMODE and EXMODE.

+ if (recovery && 
+     (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
+  goto error;
+ }

Zero terminated strings for lock names is bad taste.  It generates a bunch of 
useless strlen executions and you force an ascii namespace for no apparent 
reason.  Add a 9th parameter, namelen, to the lock call maybe?

Regards,

Daniel 

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Thu, May 19, 2005 at 02:30:23AM -0400, Daniel Phillips wrote:
> Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> useless strlen executions and you force an ascii namespace for no apparent 
> reason.  Add a 9th parameter, namelen, to the lock call maybe?
Or perhaps pass in a qstr? Anyway I have to agree. That shouldn't be
difficult to fix up.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Adrian Bunk]

On Wed, May 18, 2005 at 06:26:58PM -0700, Manish Singh wrote:
> On Thu, May 19, 2005 at 01:40:22AM +0200, Adrian Bunk wrote:
> > On Wed, May 18, 2005 at 03:33:03PM -0700, Mark Fasheh wrote:
> > >...
> > > A full patch can be downloaded from:
> > > http://oss.oracle.com/projects/ocfs2/dist/files/patches/2.6.12-rc4/complete/ocfs2-configfs-all.patch
> > >...
> > 
> > Some comments on this patch:
> > - there's no reason to make JBD user-visible
> 
> Sure, the only reason I made it visible was because of the comment in
> there:
> 
> # CONFIG_JBD could be its own option (even modular), but until there are
> # other users than ext3, we will simply make it be the same as CONFIG_EXT3_FS
> 
> I don't really have a preference either way.

I'd say the comment is wrong.

> > - is there any reason why CONFIGFS_FS is user-visible?
> 
> It's a generic mechanism for userspace driven configuration of kernel
> functionality. There's nothing specific to OCFS2 about it. Other kernel
> subsystems/projects could use it too, for their own configuration
> mechanisms. More details are in configfs.txt, which is included in the
> above patch. Note the example used in the documentation text is an NBD
> driver.
>...

If other subsystems use it, they should select it.

> -Manish

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

2.4 kernel threads

[linux]

While attempting to unload the kernel module which has created a kernel
thread whoch runs perfectly i get this oops:
Unable to handle kernel paging request at virtual address d08f364c
 printing eip:
c011d6ff
*pde = 01af0067
*pte = 00000000
Oops: 0002
parport_pc lp parport autofs pcnet_cs 8390 crc32 ds yenta_socket pcmcia_core
floppy microcode ext3 jbd
CPU:    0
EIP:    0060:[<c011d6ff>]    Not tainted
EFLAGS: 00010092

EIP is at interruptible_sleep_on_timeout [kernel] 0x4f (2.4.21-4.EL)
eax: d08f3648   ebx: 00000286   ecx: 00000286   edx: d08f3648
esi: 000001c3   edi: 00000000   ebp: cc445fdc   esp: cc445fb4
ds: 0068   es: 0068   ss: 0068
Process enigma (pid: 1622, stackpage=cc445000)
Stack: 00000000 cc444000 d08f3648 d08f3648 00000000 00000003 00000656
00000656
       d08f3060 00000000 cc445fec d08f310d 00000004 cc444000 00000000
c010945d
       d08f363c 00000000 00000000
Call Trace:   [<c010945d>] kernel_thread_helper [kernel] 0x5 (0xcc445ff0)

Code: 89 50 04 89 02 c7 45 e4 00 00 00 00 c7 45 e0 00 00 00 00 53

Kernel panic: Fatal exception



The module is being unloaded with the following procedure:
lock_kernel();
flag=1; /* This flag does a break in the for(;;) loop of the thread after
the interruptible_sleep_on_timeout , after the break current=NULL;*/
mb();
kill_proc(pid_thread,SIGKILL,1);
unlock_kernel();
kill_proc(2,SIGCHLD,1); /* assuming that keventd is running with PID 2 */

Re: [RFC] [PATCH] OCFS2

[Jeff Garzik]

Daniel Phillips wrote:
> Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> useless strlen executions and you force an ascii namespace for no apparent 
> reason.  Add a 9th parameter, namelen, to the lock call maybe?

What's wrong with ascii strings?

We call those 'UTF8' these days.

	Jeff

Re: 2.4 kernel threads

[Arjan van de Ven]

On Thu, 2005-05-19 at 13:24 +0300, linux wrote:
> While attempting to unload the kernel module which has created a kernel
> thread whoch runs perfectly i get this oops:

you failed to put in an URL to the sourcecode of your module.

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Daniel Phillips]

Hi Mark,

On Thursday 19 May 2005 02:54, Mark Fasheh wrote:
> On Thu, May 19, 2005 at 02:30:23AM -0400, Daniel Phillips wrote:
> > Zero terminated strings for lock names is bad taste.  It generates a
> > bunch of useless strlen executions and you force an ascii namespace for
> > no apparent reason.  Add a 9th parameter, namelen, to the lock call
> > maybe?
>
> Or perhaps pass in a qstr? Anyway I have to agree. That shouldn't be
> difficult to fix up.

Qstr would be nice, either that or an explicit string length.  Either way, the 
compiler will catch any missed fixups.

Regards,

Daniel

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Jeff Garzik]

Daniel Phillips wrote:
> Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> useless strlen executions and you force an ascii namespace for no apparent 
> reason.  Add a 9th parameter, namelen, to the lock call maybe?

What's wrong with ascii strings?

We call those 'UTF8' these days.

	Jeff

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Lee Revell]

On Thu, 2005-05-19 at 06:26 -0400, Jeff Garzik wrote:
> Daniel Phillips wrote:
> > Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> > useless strlen executions and you force an ascii namespace for no apparent 
> > reason.  Add a 9th parameter, namelen, to the lock call maybe?
> 
> What's wrong with ascii strings?
> 
> We call those 'UTF8' these days.

I think you just answered your own question.

Lee

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Jeff Garzik]

Lee Revell wrote:
> On Thu, 2005-05-19 at 06:26 -0400, Jeff Garzik wrote:
> 
>>Daniel Phillips wrote:
>>
>>>Zero terminated strings for lock names is bad taste.  It generates a bunch of 
>>>useless strlen executions and you force an ascii namespace for no apparent 
>>>reason.  Add a 9th parameter, namelen, to the lock call maybe?
>>
>>What's wrong with ascii strings?
>>
>>We call those 'UTF8' these days.
> 
> 
> I think you just answered your own question.

Incorrect.  Read the quoted context.

	Jeff

Re: [RFC] [PATCH] OCFS2

[Lee Revell]

On Thu, 2005-05-19 at 06:26 -0400, Jeff Garzik wrote:
> Daniel Phillips wrote:
> > Zero terminated strings for lock names is bad taste.  It generates a bunch of 
> > useless strlen executions and you force an ascii namespace for no apparent 
> > reason.  Add a 9th parameter, namelen, to the lock call maybe?
> 
> What's wrong with ascii strings?
> 
> We call those 'UTF8' these days.

I think you just answered your own question.

Lee

Re: [RFC] [PATCH] OCFS2

[Jeff Garzik]

Lee Revell wrote:
> On Thu, 2005-05-19 at 06:26 -0400, Jeff Garzik wrote:
> 
>>Daniel Phillips wrote:
>>
>>>Zero terminated strings for lock names is bad taste.  It generates a bunch of 
>>>useless strlen executions and you force an ascii namespace for no apparent 
>>>reason.  Add a 9th parameter, namelen, to the lock call maybe?
>>
>>What's wrong with ascii strings?
>>
>>We call those 'UTF8' these days.
> 
> 
> I think you just answered your own question.

Incorrect.  Read the quoted context.

	Jeff

Re: 2.4 kernel threads

[Jesse Barnes]

On Thursday, May 19, 2005 3:24 am, you wrote:
> While attempting to unload the kernel module which has created a
> kernel thread whoch runs perfectly i get this oops:
> Unable to handle kernel paging request at virtual address d08f364c

Your messages keep showing up as replies to other threads.  It looks 
like you're just hitting 'reply' to the latest message in your lkml 
mailbox in order to post a new message (at least the headers of your 
mail contain references to unrelated messages).  Please don't do this.  
Just create a new message with 'linux-kernel@vger.kernel.org' in the To 
field.  People will be more likely to see your message this way since 
it won't be buried in a thread they may or may not be interested in.

Thanks,
Jesse

Re: [RFC] [PATCH] OCFS2

[Daniel Phillips]

Hi Mark,

On Thursday 19 May 2005 02:54, Mark Fasheh wrote:
> On Thu, May 19, 2005 at 02:30:23AM -0400, Daniel Phillips wrote:
> > Zero terminated strings for lock names is bad taste.  It generates a
> > bunch of useless strlen executions and you force an ascii namespace for
> > no apparent reason.  Add a 9th parameter, namelen, to the lock call
> > maybe?
>
> Or perhaps pass in a qstr? Anyway I have to agree. That shouldn't be
> difficult to fix up.

Qstr would be nice, either that or an explicit string length.  Either way, the 
compiler will catch any missed fixups.

Regards,

Daniel

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[James Morris]

On Wed, 18 May 2005, Mark Fasheh wrote:

> This is OCFS2, a shared disk cluster file system which we hope will be
> included in the kernel.

The masklog code looks potentially useful outside of ocfs2, as a general 
kernel facility.  Any chance of splitting it out?


Quibbles:

- A lot of the macros should probably be replaced with static inlines, 
like OCFS2_IS_VALID_DINODE.

- Approx. 80 typedefs.  ouch.



-- 
James Morris
<jmorris@redhat.com>

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

Hi James,

Thanks for looking over this.

On Thu, Jun 23, 2005 at 02:03:35PM -0400, James Morris wrote:
> The masklog code looks potentially useful outside of ocfs2, as a general 
> kernel facility.  Any chance of splitting it out?
Absolutely. We've found that stuff invaluable in debugging issues for a
while now, and as far as I recall, Zach wrote it with the idea that it could
be useful to other folks too. I think the only issue to resolve there would
be how other subsystems reserve a debugging bit...

> Quibbles:
> 
> - A lot of the macros should probably be replaced with static inlines, 
> like OCFS2_IS_VALID_DINODE.
> 
> - Approx. 80 typedefs.  ouch.
Heh, we're slowly removing those :)
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[James Morris]

On Wed, 18 May 2005, Mark Fasheh wrote:

> This is OCFS2, a shared disk cluster file system which we hope will be
> included in the kernel.

The masklog code looks potentially useful outside of ocfs2, as a general 
kernel facility.  Any chance of splitting it out?


Quibbles:

- A lot of the macros should probably be replaced with static inlines, 
like OCFS2_IS_VALID_DINODE.

- Approx. 80 typedefs.  ouch.



-- 
James Morris
<jmorris@redhat.com>

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

Hi James,

Thanks for looking over this.

On Thu, Jun 23, 2005 at 02:03:35PM -0400, James Morris wrote:
> The masklog code looks potentially useful outside of ocfs2, as a general 
> kernel facility.  Any chance of splitting it out?
Absolutely. We've found that stuff invaluable in debugging issues for a
while now, and as far as I recall, Zach wrote it with the idea that it could
be useful to other folks too. I think the only issue to resolve there would
be how other subsystems reserve a debugging bit...

> Quibbles:
> 
> - A lot of the macros should probably be replaced with static inlines, 
> like OCFS2_IS_VALID_DINODE.
> 
> - Approx. 80 typedefs.  ouch.
Heh, we're slowly removing those :)
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Thu, Jun 23, 2005 at 08:05:24PM -0700, Paul Jackson wrote:
> These combine to make a 45 thousand line patch.  That's a big patch.
> Only the netdev and reiser4 patches (and the combined linus.patch)
> are bigger.
> 
> Shouldn't these be 3 patches, or more?
They are. I believe you're looking at the combined patch. If you want them
broken out, we keep those at
http://oss.oracle.com/projects/ocfs2/files/patches/

My original patch mail also had links to the broken out ones...
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

James wrote:
> Any chance of splitting it out?

Responding to your post, but I guess it's really Oracle I'm asking:

On my first glance just now at the git-ocfs patch, I was surprised that
what seemed to be separable facilities were combined into one patch.  I
see a file system, a lock manager (is that what DLM stands for - please
spell out acronyms)  and a configuration file system.


+configfs/
+       - directory containing configfs documentation and example code.
  ...
+dlmfs.txt
+       - info on the userspace interface to the OCFS2 DLM.
  ...
+ocfs2.txt
+       - info and mount options for the OCFS2 clustered filesystem.


These combine to make a 45 thousand line patch.  That's a big patch.
Only the netdev and reiser4 patches (and the combined linus.patch)
are bigger.

Shouldn't these be 3 patches, or more?

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

A couple more random questions:

 1) How does this lock manager relate to the Red Hat lock manager,
    the dlm-* patches?

    Note as an aside that dlm-* has 23 patches for a total of 14
    thousand lines, or about 600 lines per patch.  This is rather
    different than burying a lock manager into a 45 thousand line
    new file system patch ;)

 2) Would a diffstat be a useful addition to this patch?

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Thu, Jun 23, 2005 at 08:05:24PM -0700, Paul Jackson wrote:
> These combine to make a 45 thousand line patch.  That's a big patch.
> Only the netdev and reiser4 patches (and the combined linus.patch)
> are bigger.
> 
> Shouldn't these be 3 patches, or more?
They are. I believe you're looking at the combined patch. If you want them
broken out, we keep those at
http://oss.oracle.com/projects/ocfs2/files/patches/

My original patch mail also had links to the broken out ones...
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

Mark wrote:
> My original patch mail also had links to the broken out ones...

Ok - good.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

James wrote:
> Any chance of splitting it out?

Responding to your post, but I guess it's really Oracle I'm asking:

On my first glance just now at the git-ocfs patch, I was surprised that
what seemed to be separable facilities were combined into one patch.  I
see a file system, a lock manager (is that what DLM stands for - please
spell out acronyms)  and a configuration file system.


+configfs/
+       - directory containing configfs documentation and example code.
  ...
+dlmfs.txt
+       - info on the userspace interface to the OCFS2 DLM.
  ...
+ocfs2.txt
+       - info and mount options for the OCFS2 clustered filesystem.


These combine to make a 45 thousand line patch.  That's a big patch.
Only the netdev and reiser4 patches (and the combined linus.patch)
are bigger.

Shouldn't these be 3 patches, or more?

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

A couple more random questions:

 1) How does this lock manager relate to the Red Hat lock manager,
    the dlm-* patches?

    Note as an aside that dlm-* has 23 patches for a total of 14
    thousand lines, or about 600 lines per patch.  This is rather
    different than burying a lock manager into a 45 thousand line
    new file system patch ;)

 2) Would a diffstat be a useful addition to this patch?

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

[Ocfs2-devel] Re: [RFC] [PATCH] OCFS2

[Paul Jackson]

Mark wrote:
> My original patch mail also had links to the broken out ones...

Ok - good.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

On Tue, Jun 21, 2005 at 05:43:13PM -0500, Steve French wrote:
> The list is not wrong. I was just noting that it was too short, missing
> three items of particular interest for server filesystems (which seems
> to be the target environment). Support for:
> 	Directory change notification (F_NOTIFY)
> 	Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
> 	POSIX ACLs
Ahh, it seems I misread your earlier e-mail! In any case, I'll add those to
the list of missing features.

> The lack of support for lsattr/chattr (chflags) is less important, and
> the lack of support for the multipage operations (writepages and
> readpages) is not a compatability issue and is not critical, although it
> might hurt performance.
Yeah, I'm not sure how high a priority chflags are right now. Keeping in
mind that I'm mostly ignorant of cifs / samba, is there a particular set of
attributes there that it likes to use?

I'll have to look into why we don't currently support readpages /
writepages. I'm guessing it boiled down to lack of developer time :)
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Steve French]

On Tue, 2005-06-21 at 17:03, Mark Fasheh wrote:

> If you see anywhere our supported feature set is actually misstated, please
> let me know so I can correct that immediately.

The list is not wrong. I was just noting that it was too short, missing
three items of particular interest for server filesystems (which seems
to be the target environment). Support for:
	Directory change notification (F_NOTIFY)
	Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
	POSIX ACLs
The lack of support for lsattr/chattr (chflags) is less important, and
the lack of support for the multipage operations (writepages and
readpages) is not a compatability issue and is not critical, although it
might hurt performance.

I did see that you have aio - and that was interesting because there are
so few implementations and that as well as vectorio was something I
wanted to explore for the cifs vfs client.

Re: [RFC] [PATCH] OCFS2

[Mark Fasheh]

Hi Steve,
On Tue, Jun 21, 2005 at 04:14:29PM -0500, Steve French wrote:
> You list features which OCFS2 does not support yet in fs/Kconfig as:
>                - extended attributes
>                - readonly mount
>                - shared writeable mmap
>                - loopback is supported, but data written will not
>                  be cluster coherent.
>                - quotas
>                - cluster aware flock

I think you may have misread that... the latest patch at least has:
+	  Note: Features which OCFS2 does not support yet:

If you see anywhere our supported feature set is actually misstated, please
let me know so I can correct that immediately.

> The above three (notify/lease/acl) are particularly important for
> Samba.  Are those planned for an upcoming release?
Generally we want to be as useful as possible, so we've got a long list of
planned features. I'd need to look more closely at the issues involved with
supporting these in a clustered environment before giving you any more
specific of an answer :)

> What is the timestamp granularity in your inode on-disk format?  For
> Samba4 supporting at least a 100nanosecond time stamp (used for DCE and
> CIFS) is helpful due to the time rounding issues that can come up with
> the primitive 1 second timestamp.
OCFS2 supports subsecond timestamps via a u32 nsec fields on dinode, so I
think at least that should work for you.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com

Re: [RFC] [PATCH] OCFS2

[Steve French]

You list features which OCFS2 does not support yet in fs/Kconfig as:
               - extended attributes
               - readonly mount
               - shared writeable mmap
               - loopback is supported, but data written will not
                 be cluster coherent.
               - quotas
               - cluster aware flock

It also does not appear to support various fcntls, in particular
	F_NOTIFY (directory change notification, needed by Samba. Also
		for various file manager GUIs used by Linux desktops)
	GETLEASE/SETLEASE (also needed for file caching for Samba and	
		IIRC for NFSv4 as well)
and the source tree does not seem to support "POSIX ACLs" (support for
NTFS/CIFS ACLs or the somewhat similar NFSv4 ACLs could also be mapped
by Samba as an alternative, as we do with AFS ACLs today, if you do not
wish to support POSIX ACLs)

The above three (notify/lease/acl) are particularly important for
Samba.  Are those planned for an upcoming release?

You also do not seem to handle fs ioctls - in particular any of the
	chflags/lsattr "ext attributes" (which ext2/ext3/reiser etc.do)
although they are less important.


What is the timestamp granularity in your inode on-disk format?  For
Samba4 supporting at least a 100nanosecond time stamp (used for DCE and
CIFS) is helpful due to the time rounding issues that can come up with
the primitive 1 second timestamp.