|
|
| (10 intermediate revisions by 2 users not shown) |
| Line 1: |
Line 1: |
| − | When [[Namesys]] was still in place, there was a [http://pub.namesys.com/Reiser4/ToDo TODO list] to work on to get [[Reiser4]] into mainline. This URL is no more, but back in 08/2008, Andrew and Edward put together an [http://marc.info/?l=reiserfs-devel&m=121789281206672&w=2 updated Reiser4 TODO list]: | + | When [https://en.wikipedia.org/wiki/Namesys Namesys] was still in place, there was a [https://web.archive.org/web/20071219121554/http://pub.namesys.com/Reiser4/ToDo TODO list] (archive.org) to work on to get [[Reiser4]] into mainline. This URL is no more and a lot of changes have been made to Reiser4, the most current TODO list we have is from April 2009 and there're still enough tasks left to be done: |
| | | | |
| − | <pre>
| + | * [https://marc.info/?l=reiserfs-devel&m=124069989217533 updated TODO list from 2009-04-25] |
| − | List: reiserfs-devel
| + | * [https://www.spinics.net/lists/reiserfs-devel/msg01028.html updated TODO list from 2008-08-05] |
| − | Subject: Todo for inclusion (updated 05 Aug 2008)
| + | * [[TODO/2007-11-25|original TODO list from 2007-11-25]] |
| − | From: Edward Shishkin <edward.shishkin () gmail ! com>
| + | * Storage [[Containers]] |
| − | Date: 2008-08-04 23:35:32
| + | |
| − | Message-ID: 48979244.3040903 () gmail ! com
| + | |
| − | [Download message RAW] | + | |
| − | | + | |
| − | Todo for inclusion (updated 05 Aug 2008)
| + | |
| − | | + | |
| − | | + | |
| − | The updated todo-list initially composed by Akpm is attached.
| + | |
| − | It makes sense to try to address the following items
| + | |
| − | (complexity is increased):
| + | |
| − | | + | |
| − | #10,11: Cleanups.
| + | |
| − | | + | |
| − | #3 There is a pending patch to review/merge:
| + | |
| − | http://marc.info/?l=reiserfs-devel&m=119316601418489&w=2
| + | |
| − | | + | |
| − | #9: I don't see any leaked jref there. Perhaps we need to rewrite this
| + | |
| − | portion of code to make it more clear.
| + | |
| − | | + | |
| − | #14 needs to be addressed.
| + | |
| − | | + | |
| − | ["todo_for_inclusion_cached" (text/plain)]
| + | |
| − | | + | |
| − | Tasks are needed to done for getting reiser4 code into the kernel as found by AKPM
| + | |
| − | in 2.6.18-rc2-mm1 (# means that an issue is done)
| + | |
| − | | + | |
| − | 1. running igrab() in the writepage() path is really going to hammer inode_lock.
| + | |
| − | Something else will need to be done here.
| + | |
| − | | + | |
| − | 2. The preferred way of solving the above would be to mark the page as
| + | |
| − | PageWriteback() with set_page_writeback() prior to unlocking it. That'll pin
| + | |
| − | the page and the inode. It does require that the page actually get written later on.
| + | |
| − | If we cannot do that then more thought is needed.
| + | |
| − | | + | |
| − | 3. If poss, use wake_up_process() rather than wake_up(). That'll save some locking.
| + | |
| − | | + | |
| − | 4. Running iput() in entd() is a bit surprising. iirc there are various ways in which
| + | |
| − | this can recur into the filesystem, perform I/O, etc. I guess it works.. But again,
| + | |
| − | it will hammer inode_lock.
| + | |
| − | | + | |
| − | 5. the writeout logic in entd_flush() is interesting (as in "holy cow"). It's very
| + | |
| − | central and really needs some good comments describing what's going on in there -
| + | |
| − | what problems are being solved, which decisions were taken and why, etc. The big
| + | |
| − | comment in page_cache.c is useful. Please maintain it well. Boy, it has some old
| + | |
| − | stuff in it.
| + | |
| − | | + | |
| − | 6. reiser4_wait_page_writeback() needs commenting.
| + | |
| − | | + | |
| − | 7. reading the comment in txnmgr.c regarding MAP_SHARED pages: a number of things
| + | |
| − | have changed since then. We have page-becoming-writeable notifications and probably
| + | |
| − | soon we'll always take a pagefault when a MAP_SHARED page transitions from pte-clean
| + | |
| − | to pte-dirty (although I wouldn't recommend that a filesystem rely upon the latter
| + | |
| − | for a while yet).
| + | |
| − | | + | |
| − | 8. page_cache.c: yes, mpage_end_io_write() and mpage_end_io_read() are pretty generic
| + | |
| − | - we might as well export them.
| + | |
| − | | + | |
| − | 9. truncate_jnodes_range() looks wrong to me. When we populate gang[], there can be any
| + | |
| − | number of NULL entries placed in it. But the loop which iterates across the
| + | |
| − | now-populated gang[] will bale out when it its the _first_ NULL entry. Any following
| + | |
| − | entries will have a leaked jref() against them.
| + | |
| − | | + | |
| − | 10. Waaaaaaaaaaaaaaay too many typedefs.
| + | |
| − | | + | |
| − | 11. There are many coding-style nits. One I will mention is very large number of unneeded braces:
| + | |
| − | * if (foo) {
| + | |
| − | o bar();
| + | |
| − | }
| + | |
| − | it'd be nice to fix these up sometime. Note: Easy to find and repair with checkpatch.pl
| + | |
| − | script found at http://www.kernel.org/pub/linux/kernel/people/apw/checkpatch/
| + | |
| − | | + | |
| − | 12. General comment: the lack of support for extended attributes, access control lists and
| + | |
| − | direct-io is a big problem and it's getting bigger. I don't see how a vendor could
| + | |
| − | support reiser4 without these features and permanent lack of vendor support will hurt.
| + | |
| − | What's the plan here?
| + | |
| − | | + | |
| − | 13. (from CH) Another issue is the lack of support for blocksize < pagesize. This prevents it
| + | |
| − | from being used across architectures. Even worse when I tried the last time it didn't allow
| + | |
| − | me to create a 64k blocksize filesystem that I could actually test on ppc64. \
| + | |
| − | | + | |
| − | 14. set_page_dirty_internal() pokes around in VFS internals. Use set_page_dirty_no_buffers()
| + | |
| − | or create a new library function in mm/page-writeback.c. In particular, it gets the
| + | |
| − | radix-tree dirty tagging out of sync.
| + | |
| − | | + | |
| − | 15. #wbq.sem should be using a completion for the "wait until entd finishes", not a semaphore.
| + | |
| − | Because there's a teeny theoretical race when using semaphores this way which completions
| + | |
| − | were designed to avoid. (The waker can still be playing with the semaphore when it has
| + | |
| − | gone out of scope on the wakee's stack).
| + | |
| − | | + | |
| − | 16. #write_page_by_ent(): the "spin until entd thread" thing is gross. This function is really
| + | |
| − | lock-intensive.
| + | |
| − | | + | |
| − | 17. #entd_flush(): bug:
| + | |
| − | rq->wbc->range_start = rq->page->index << PAGE_CACHE_SHIFT;
| + | |
| − | this can overflow on 32-bit. Need to cast rq->page->index to loff_t.
| + | |
| − | | + | |
| − | 18. #writeout() is a poor name for a global function. Even things like "txn_restart" are a bit
| + | |
| − | generic-sounding. Low-risk, but the kernel's getting bigger... If it were mine, I'd prefix
| + | |
| − | all these symbols with "r4_". prepare_to_sleep(), page_io(), drop_page(), statfs_type(),
| + | |
| − | pre_commit_hook(), etc, etc, etc, etc. Much namespace pollution.
| + | |
| − | | + | |
| − | 19. #invalidate_list() is a poorly-chosen global identifier. We already have an invalidate_list()
| + | |
| − | in fs/inode.c, too. Please audit all of reiser4's global identifiers (use nm *.o) for
| + | |
| − | suitable naming choices.
| + | |
| − | | + | |
| − | 20. #semaphores are deprecated. Please switch to mutexes and/or completions where appropriate
| + | |
| − | and possible.
| + | |
| − | | + | |
| − | 21. #drop_page() is a worry. Why _does_ reiser4 need to remove pages from pagecache? That
| + | |
| − | isn't a filesystem function. drop_page() appears to leave the no-longer-present page tagged
| + | |
| − | as dirty in the radix-tree.
| + | |
| − | | + | |
| − | 22. #reiser4_invalidate_pages() is a mix of reiser4 things and of things-which-the-vfs-is-supposed-to-do.
| + | |
| − | It is uncommented and I am unable to work out why it was necessary to do this, and hence what we
| + | |
| − | can do about it.
| + | |
| − | | + | |
| − | 23. #reiser4_readpages() shouldn't need to clean up the remaining pages on *pages. read_cache_pages()
| + | |
| − | does that now.
| + | |
| − | | + | |
| − | 24. #<wonders what formatted and unformatted nodes are> A brief glossary might help.
| + | |
| − | | + | |
| − | 25. #REISER4_ERROR_CODE_BASE actually overlaps real errnos (see include/linux/errno.h). Suggest that
| + | |
| − | it be changed to 1000000 or something.
| + | |
| − | | + | |
| − | 26. #blocknr_set_add() modifies a list_head without any apparent locking. Certainly without any
| + | |
| − | _documented_ locking... Ditto blocknr_set_destroy(). I'm sure there's locking, but it's harder than
| + | |
| − | it should be to work out what it is. Given that proper locking is in place, the filesystem seems to
| + | |
| − | use list_*_careful() a lot more than is necessary?
| + | |
| − | | + | |
| − | 27. #It would be clearer to remove `struct blocknr_set' and just use list_head.
| + | |
| − | | + | |
| − | Last update: 02/06/2007
| + | |
| − | Reiser4/ToDo (last edited 2007-11-25 21:57:14 by M9132)
| + | |
| − | </pre>
| + | |
| − | | + | |
| − | ----
| + | |
| − | [http://www.nabble.com/reiser4-inclusion--p23116865.html Reiser4 inclusion] seems to be in sight, rumor has it that another attempt will be made later this year. | + | |
| | | | |
| | + | That being said, <s>reiser4 inclusion seems to be in sight</s>, rumor has it that another attempt will be made [https://marc.info/?l=reiserfs-devel&m=124904274311847 in late 2010] or [https://www.spinics.net/lists/reiserfs-devel/msg02496.html early 2011]. |
| | | | |
| | [[category:Reiser4]] | | [[category:Reiser4]] |
