[ros-dev] IFS wrapper project proposal draft

Tue Apr 5 08:02:14 UTC 2011

I would also recommend looking at porting JFS - the sources are available.  
This is the file system that IBM originally used in OS/2 Warp 4.5X (and  
also AIX if I am not mistaken) and is a very solid file system. Something  
IBM seemed to be doing right.

I am not sure about all the details of it, but AFAIK it also supports  
things like ACLs too.

On Tue, 05 Apr 2011 17:56:40 +1000, Love Nystrom <love.nystrom at gmail.com>  
wrote:

> Hi Bryan,
>
> Just like Aleksey, I would welcome an effort to simplify IFS  
> implementation.
>
> Seen as NTFS is (and always will be?) not well documented, I've been
> thinking about
> supporting some alternative, OSS, journaling file system in ReactOS, e.g.
> ReiserFS,
> to allow us to provide the (relative) fail-safety of file transaction
> journaling that NTFS has.
> Also, hopefully, to enable us to implement NT's access privilege
> system (Security) on files.
>
> So far, it remains just a thought, since I can't allocate the time to  
> adapt
> e.g ReiserFS to
> an NT IFS, and if I'm not mistaken, our IFS implementation has  
> shortcomings
> of it's own
> which You may need to address as well in implementing Your proposal.
>
> In addition to "Windows NT File System Internals" I would also recommend
> "Windows Internals, 4th Edition" for additional/complementary insight.
> Especially Ch.12 "File Systems", but Ch.8-12 are all relevant, and the  
> whole
> book is strongly recommended (by everyone, I think).
>
> It will be a BIG job I think (thesis big), and I hope You have the
> structural
> "common sense" to make it a success, and not a mess ;).
> It would be most welcome !
>
> Comment Your code scrupulously :)
>
> Best Regards
> // Love
>
> On Sun, Apr 3, 2011 at 1:55 PM, <ros-dev-request at reactos.org> wrote:
>
>> ---------- Forwarded message ----------
>> From: Bryan Donlan <bdonlan at gmail.com>
>> To: ReactOS Development List <ros-dev at reactos.org>
>> Date: Sat, 2 Apr 2011 18:26:23 -0400
>> Subject: [ros-dev] [GSoC] IFS wrapper project proposal draft
>> Hello,
>>
>> After reading the ReactOS GSoC ideas page, I became interested in the
>> IFS wrapper driver project idea[1], and would appreciate any comments
>> on my project proposal before I formally submit it.
>>
>> First, a bit about me. I am a student in a dual-major program,
>> studying Computer Science and Japanese at the University of
>> Massachusetts at Amherst. I have had some experience in kernel
>> development previously; as part of an internship at a research project
>> at my University, I wrote some network flow analysis code running in
>> the Linux kernel. While filesystem work will be a first for me, I
>> think it will be an interesting leaning experience. I am fluent in
>> English and Japanese, and am in the UTC-0400 timezone (TZ=US/Eastern).
>> My freenode username is bd_, and my myReactOS username is bdonlan.
>>
>> In preparation for writing this proposal, I obtained a copy of the
>> "Windows NT File System Internals: A Developer's Guide" book from
>> O'Reilly. Although a bit dated, it has been enourmously helpful in
>> helping me get an idea of what I'm getting into.
>>
>> My goal in this project will be to write a library to significantly
>> simplify writing a NT File System Driver. Although writing a
>> kernel-mode filesystem will never be as easy as with, eg, FUSE, it
>> should be possible to abstract away many of the idiosyncracies of the
>> NT filesystem API, at least. For example, the wrapper library may
>> handle:
>> * Automatically queueing asynchronous filesystem operations on a worker
>> thread
>> * Parsing paths and invoking a FS-supplied traversal function for each
>> directory element
>> * Interfacing with the NT cache manager, including flushing data from
>> the cache when a non-cached operation is performed on a cached file,
>> and establishing cache maps for the underlying device for a disk-based
>> file system
>> * Providing a common implementation of byte range locks and oplocks,
>> and disabling fast I/O when they are in use
>> * Caching directory entry lookups
>> * Performing typical input validation/security checks needed by all NT
>> filesystems
>> * Helper tools may also be provided to load pseudo-filesystems
>> (filesystems with neither network nor disk backing) on an ad-hoc basis
>>
>> Essentially, the library should make it easy for the filesystem
>> designer to focus on the actual filesystem, rather than the NT IFS
>> interfaces - a read call would be able to skip all the preparation and
>> checks, and directly go to perform the actual I/O.
>>
>> Major milestones for the project may include:
>> - Prepare a sketch of the API and callbacks for the IFS helper library
>> (subject to change if necessary)
>> - Implement enough of the wrapper library to implement a simple
>> pseudo-filesystem demonstrating non-cached reads and writes
>> - Add support for cached reads/writes (interaction with the cache
>> manager, caching for on-disk metadata)
>> - Demonstrate a disk-based filesystem without metadata update support
>> (MINIX FS or FAT?)
>> - Demonstrate a disk-based filesystem with full read-write support
>> - If time allows, add support for ancillary features, such as byte
>> locks, oplocks, and notify watchers.
>>
>> The interfaces exposed by the filesystem library will of course be
>> clearly documented. Filesystems needing more advanced support will
>> also be able to override any IFS callbacks they choose.
>>
>> I have an existing consulting commitment that will take some of my
>> time, but I expect to be able to put in 20-30 hours of work per week
>> into this project. Further, I hereby swear that I have not used nor
>> seen the source code to any version of the Windows operating system
>> nor any Microsoft product that may be related to the proposed project
>> that is under a license incompatible with contribution to ReactOS,
>> including but not limited to the leaked Windows 2000 source code and
>> the Windows Research Kernel.
>>
>> I would appreciate any comments on my proposal before formally
>> submitting it to the GSoC site.
>>
>> Thanks,
>>
>> Bryan Donlan
>>
>>

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