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Diffstat (limited to 'user/scolobb.mdwn')
| -rw-r--r-- | user/scolobb.mdwn | 82 |
1 files changed, 59 insertions, 23 deletions
diff --git a/user/scolobb.mdwn b/user/scolobb.mdwn index b481f235..cddb1c73 100644 --- a/user/scolobb.mdwn +++ b/user/scolobb.mdwn @@ -16,10 +16,10 @@ Mail: <mailto:unlimitedscolobb@gmail.com> # Google Summer of Code: 2009 Project -**Unionmount**: The goal of this project is to make it possible to -mount a translator on a node in such a way that the contents of the -node be merged with the (virtual) filesystem published by the -translator. +**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]]. @@ -29,27 +29,64 @@ For documentation, see [[hurd/translator/unionmount]]. ### DONE -* Make unionfs build. - -* Change the command line parsing in unionfs to comply with the - requirements of unionmount. - -* Start the mountee. +* **Make `unionfs` build.** 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`.** 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.** 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.** `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. ### TODO -* Include the filesystem published by the mountee in the list of - merged filesystems. - -* Use a different (better?) implementation idea. - -* Write documentation. - -* Push the unionmount branch (*master-scolobb-unionmount*) to the - unionfs repository. - -* Derive an independent repository based on the - *master-scolobb-unionmount* branch. +* **Use a different (better?) implementation idea.** It has been + pointed out several times that `unionmount` could be implemented not + by forking off `unionfs`, but by keeping the merging functionality + in a stand-alone module (which could then be used by `unionfs` as + well). Different implementation ideas with their own specific + advantages may also arise in the future. + +* **Write documentation.** The basic unionmount functionality being + finished, it has to be documented properly, lest it should lag + behind and remain unfinished eventually. + +* **Decide as to location of unionmount.** Presently, `unionmount` is + a (local) branch in `unionfs` git repository. The first step of + publishing it is planned to be pushing it to the Savannah `unionfs` + repository. Some agree that there should also be a second step + consisting in splitting `unionmount` in a separate git repository, + since the destinations of `unionfs` and `unionmount` are *similar*, + and not identical. --- @@ -170,4 +207,3 @@ The code is at <http://github.com/scolobb/nsmux/tree/master>. ####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. - |