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diff --git a/user/scolobb.mdwn b/user/scolobb.mdwn new file mode 100644 index 00000000..017936e5 --- /dev/null +++ b/user/scolobb.mdwn @@ -0,0 +1,364 @@ +[[!meta copyright="Copyright © 2008, 2009 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU Free Documentation License|/fdl]]."]]"""]] + + +Sergiu Ivanov + +Mail: <mailto:unlimitedscolobb@gmail.com> + +# Current Activity + +I am currently busy finishing the university semester, this is why I +am rather passive. + +## Roadmap + +* **Build `nsmux` under the Hurd tree** -- **antrik** has been urging + me to do this for a long time, so I definitely have to give it a + try. + +* **Try Thomas's `nsmux-notify` branch** -- To support his stance + against including `nsmux` in the Hurd source tree, Thomas added to + `nsmux` the ability to listen to port notification (as I understand + it). I have to try that, too. + +* **Make proxy nodes go away when the proxied translator goes away** + -- This should be done by listening to notifications on the ports to + the proxied translators. A similar functionality is already + implemented in `unionmount`, but it was decided that `nsmux` should + use standard notification interfaces, as opposed to the custom + demuxer and handler implemented in `unionmount`. + +* **Don't attach anonymous translators** -- There is no special point + in attaching anonymous (formerly known as dynamic) translators to + specific nodes. Keeping them orphan should simplify the design of + `nsmux` by eliminating the need for shadow nodes, whose main purpose + was to serve as virtual locations to attach translators to. + +* **Setup a list of nodes proxying static translators** -- This list + is needed when for the filter, which should also be able to go down + the static translator stack, not only the stack of anonymous + translators. + +* **Cleanup `nsmux`** -- When I was writing `nsmux` my acquaintance + with good coding and code formatting practices was very basic, which + resulted in messy and sometimes ugly code. + +* **Implement recursive propagation of translators down directories** + -- This task was planned long ago and is fascinating, but I won't be + working on it in the near future. + +--- + +# Google Summer of Code: 2009 Project + +**Unionmount**: The goal of this project is to make it possible to set +translators in unionmount mode, which means that the filesystem +published by the mounted translator will get merged with the directory +tree of the node the translator is mounted onto. + +For documentation, see [[hurd/translator/unionmount]]. + +At the Final Evaluation, this project was given a passing evaluation +by **antrik**. This means that the union-mount functionality is +working and has been tested normally to collaborate with +`eth-multiplexer`. + +--- + +## Roadmap + +### DONE + +(Dates in brackets show the completion date) + +* **Make `unionfs` build.** *(24 May)* For reasons unknown to me, + `unionfs` Makefile was configured to search for include files from + under `$(prefix)/include`, while `$(prefix)` was never + defined. Setting `$(prefix)` to `/usr` solved the problem. + +* **Change the command line parsing in `unionfs` to comply with the + requirements of `unionmount`.** *(25 May)* Although the core + functionality of `unionmount` heavily relies on `unionfs`, the + command line interface of these two programs is completely + different: `unionfs` operates on directories, the list of which is + explicitly specified, while `unionmount` *always* merges the + underlying filesystem and the filesystem published by the + mountee. Therefore, options like `--add`, `--remove`, `--underlying` + (specific to `unionfs`) make little sense in `unionmount` + context. These options have been removed. Also, `unionmount` must be + able to pass some switches to the mountee, which means that it + should stop parsing the command line arguments immediately after + having encountered the path to the mountee (very similar to how + `settrans` works). This functionality has also been implemented. + +* **Make `unionmount` capable of starting the mountee.** *(28 May)* + The idea behind implementation of this goal is that `unionmount` + should provide a proxy node on which to set the mountee. The main + issue about this goal was the fact that the mountee *cannot* be + started during the initialization of `unionmount`, because in this + phase `unionmount` is not capable of responding to RPCs, while many + translators try to `io_stat` their underlying node or do other + interesting things on startup. The solution to this problem is, + obviously, *lazy* startup, i.e. the mountee is started at the first + attempt to access (via `dir_lookup` or `dir_readdir`) the merged + filesystem published by `unionmount`. + +* **Include the filesystem published by the mountee in the list of + merged filesystems.** *(1 Jun)* `unionfs` operates on a list of + ports to the underlying filesystems, therefore, to finish the + unionmount functionality, I had to include the port to the mountee + in this list. + +* **Learn Texinfo.** *(Jun 4)* In order to produce canonical + documentation I had to learn the Texinfo documentation format. + +* **Write documentation for `unionmount`.** *(Jun 5)* The basic + unionmount functionality being finished, it has to be documented + properly, lest it should lag behind and remain unfinished + eventually. + +* **Write documentation for `unionfs`.** *(Jun 5)* `unionfs` is not + exactly well-documented at the moment, the only help being provided + by the comments in the sources. The goal is to write a more coherent + documentation. + +* **Start with a clean unionfs and implement the `--mount` argument** + *(11 Jun)* It was suggested to implement the union mount + functionality first, instead of doing some partial adaptation of + `unionfs` to `unionmount` and leaving the complete adaptation for + the future. + +* **Compile GNU/Hurd from source to be able to study + eth-multiplexer.** *(16 Jun)* On my way to getting a working + instance of eth-multiplexer I learnt how I could compile GNU/Hurd in + a Debian GNU/Hurd system. + +* **Setup the `devnode`--`eth-multiplexer`--`pfinet chain`.** *(30 + Jun)* Due to the fact that I was trying to build everything using + `gcc-4.3`, I got strange behaviour of pfinet and spend a week trying + to figure out the reason. + +* **Try to start the mountee during initialization of `unionfs`** *(4 + Jul)* Initially the mountee was started at the first lookup. Now it + is started immediately after initialization of `unionmount`. + +* **Fix the patches in `--mount` option series** *(5 Jul)* The patches + have been reviewed by **antrik**. I corrected them and posted them + to the ML for final reviews. + +* **Orphan the mountee after starting it** *(7 Jul)* Orphaning the + mountee after starting it up seems to be a nice work-around for the + necessity of keeping a proxy node in unionmount in simple + use-cases. It is possible that this functionality will provided as a + separate patch (without inclusion in master) should it turn out that + orphaning the mountee is a bad idea. + +* **Decide which RPCs should be forwarded to the mountee and how this + should happen** *(10 Jul)* This is the primary requirement in being + able to proxy the control port of `unionmount`. + +* **Fix the patches the have already been commented on** *(14 Jul)* + The new patches I have submitted have been reviewed; also, the older + patches have been reviewed again, which required correcting them. + +* **Add the `--no-mount` option** *(14 Jul)* Using the `--no-mount` + and `--mount` options, the user can decide whether unionmount should + be completely transparent (i.e. most control-port RPCs forwarded to + the mountee) or not. + +* **Make `unionmount` go away when the mountee goes away** *(14 Jul)* + `unionmount` makes sense only while the mountee is running, so it + has to go away as soon as the mountee has been shut down for some + reason. + +* **Proxy the control port of `unionmount`** *(14 Jul)* For + `unionmount` to become transparent, most of the RPCs invoked on the + its control port should be forwarded to the mountee. + +* **Fix adding filesystems to `unionmount`** *(16 Jul)* `settrans -a + foo unionfs -a <dir> -u -t <translator>` worked, but `settrans -a + foo unionfs -u -t <translator> -a <dir>` didn't. The problem was + that in a series of rebase operations I accidentally left the + "Orphan the mountee" commit out and the problem appeared when the + `start_mountee` function tried to attach the mountee. Of course, + this is not the definite solution, since I don't know why should the + attempt to attach the mountee work in the former case and fail in + the latter, but I will leave the investigation for some future time. + +* **Create the patch for supplying the mountee with a port to the + underlying node of unionfs** *(17 Jul)* Such functionality makes + `unionmount` even more transparent. + +* **Try to make `eth-multiplexer` work with static instances of + `devnode`** *(3 Aug)* A static `devnode` translator is a `devnode` + translator which is told to use the eth-multiplexer's pseudo master + device port via the "-M" option. Technically it looks like + `settrans -a <node> devnode -M <dir> <device-name>`, where `<dir>` + is the node on which eth-multiplexer is running. + + The problem was in the fact that the root node of `eth-multiplexer` + was not treated completely similarly as other nodes; specifically no + device port was created for it. Minor modifications to some + conditions solved the problem. + +* **Add the `MASTER` node to `eth-multiplexer`** *(5 Aug)* The + `MASTER` node, published by eth-multiplexer, allows creating any + number of virtual devices. This node is mainly accessed by static + instances of `devnode` to setup their corresponding virtual devices. + +* **Add support for priorities** *(6 Aug)* Now the mountee's + filesystem can be configured to "lie" beneath other filesystems. + +* **Use `unionmount` to merge the virtual filesystem of + `eth-multiplexer` with its underlying filesystem** *(7 Aug)* + `eth-multiplexer` can is unionmounted to "lie beneath" it's + underlying filesystem. If, for example, the multiplexer is + unionmounted on `veth/`, the user can both set (static) `devnode` + translator on the nodes shown in `veth/` and belonging to the + underlying filesystem and create normal virtual multiplexer devices + by accessing any node (not present in the underlying filesystem) and + opening a device using the port to the node as a pseudo device port. + +* **Rename the `MASTER` node into `.MASTER`** (7 Aug) This name seems + more natural for a special-purpose node. + +* **Set the stat information for `eth-multiplexer` nodes in + `netfs_validate_stat`** (9 Aug) In the initial version the stat + information was set up properly only at device creation. Before + that the stat information was copied from the underlying node, which + baffled `unionmount`. Now the stat information is setup in + `netfs_validate_stat`. + +* **Supply the mountee with the real root.** *(14 Aug)* Since the + mountee is *not attached* to its underlying node, it is okay to + supply it with the real root node of `unionfs`. The mountee's + filesystem will not obscure the `unionfs`'s one because the mountee + is *not attached* to the root node. + +--- + +# Google Summer of Code: 2008 Project: Namespace-based translator selection + +--- + +## Current Task + +Write the filesystem proxy for namespace-based translator selection (*nsmux*). + +The code is at <http://github.com/scolobb/nsmux/tree/master>. + +--- + +###Did this week + +* Modified the node cache so that it maintains shadow nodes alive. + +###Plans for the next week + +* Implement the shutting down of translator stacks when *nsmux* is asked to go away (in case **antrik** considers that necessary). + +* Make *nsmux* provide the access to the translator stack of the real node, in case a translator (mainly, a filter) should ask for its underlying node to be opened in O_NOTRANS mode. + +--- + +###Current Status + +####DONE: + +* The skeleton which mirrors the filesystem. + +* Provide proxy nodes (modify the standard version of netfs_S_dir_lookup). + +####TODO: + +* Create the generic filtering translator. + +* Create the translator '0' (providing the untranslated version of the + node). + +* Create the "recursive wrappers" for one-node translators. + +* Create special translators for the main proxy so that its functionality + should be complete. + +* Implement sharing of dynamic translator stacks where possible. + +* Make dynamic translators go away as soon as they are not required. + +* Refine the skeleton in several places so that it should become faster + and more reliable. + +* Kill bugs. + +* Integrate nsmux upstream. + +* Solve the libtrivfs stacking issue. + +* Patch libnetfs (it does not support file_get_translator_cntl, for + instance). + +--- + +###Progress + +####8: Fri Sep 19: + +> Modified the ncache so that it now maintains shadow nodes (and directory nodes too, it is a side effect at the moment) alive. + +####7: Sat Aug 30 - Fri Sep 5: + +> Added the code for shutting down dynamic translator stacks. + +####6: Mon Aug 4 - Fri Aug 29: + +> Implemented the proxy nodes. + +####5: Thu Jul 24 - Thu Jul 24: + +> Created a *libnetfs*-based one-node translator, working exactly like the *libtrivfs*-based translator I had written before; the former, however, can be included in a translator stack. + +####4: Tue Jul 22 - Thu Jul 24: + +> Attempted to make a *libtrivfs*-based translator to be able to be stacked upon itself (to be able to receive a translator on top of itself, more exactly); attempted to borrow some code from *libnetfs* but this didn't bring any results. + +####3: Sun Jul 20 - Tue Jul 22: + +> Implemented the possibility to propagate a translator on all files belonging to a directory 'dir' in the request of the type 'dir,,x/'. + +####2: Thu Jul 17 - Fri Jul 18: + +> Extended the lookup code in *nsmux* to allow for looking up nodes like 'file,,x' and added the possibility to escape the double-comma in the following way: ',,,'. + +####1: Mon Jul 12 - Tue Jul 13: + +> Implemented a simple *libtrivfs*-based translator to test the lookup code for *nsmux*. + +####0: Sat Jul 12 - Sat Jul 12: + +> Made small changes to the code of *filterfs* to fit the needs of *nsmux*. + +--- + +## Completed Tasks + +####2: Sat May 3 - Fri Jul 17: + +> Write a translator that should filter the contents of the directory it is set on according to some property. The property can be an arbitrary command. + +> The code is at <http://github.com/scolobb/filterfs/tree/master>. + +####1: Mon Apr 28 - Wed Apr 30: + +> Wrote a Python extension module in C for retreiving the uptime. The module is based on the code of *w*. + +####0: Sun Apr 27: + +> Followed the code of *dmesgd* (<http://www.bddebian.com/junk/dmesgd/>) kindly offered by **bddebian** and rewrote it from scratch as a tutorial. |