MiniFODevel < Know

---+mini_fo development page

%TOC%
---+++Bug reports (please add here):
|*ID*|*Description*|*Status*|*Posted by*|
| 000 | mini_fo fs explodes cdrom during mount (just joking) | closed | Markus |
| 001 | hard links in the base fs are treated as individual files | open | Markus |
| 002 | overwriting a running binary fails (ok) but truncates the binary (bad) | open | Markus |
| 003 | exporting mini_fo with nfs causes trouble. | open | Markus |

---+++Bug details:

*002:*

_Problem:_
The problem is a hack in mini_fo_mmap() in file.c, where vma->vm_file is changed to point to the lower file. First deny_write_access() is called on the mini_fo file, which (correctly) decrements its file->f_dentry->d_inode->i_writecount. But after the switch the lower i_writecount is still zero, what leads to get_write_access() succeeding and the binary beeing truncated.

_Solution:_
No easy one. 
Ugly: hack to synchronize the i_writecounts of mini_fo and lower inodes.
Properly: implement mini_fo aops to do fan-out. 

---+++Todo
   * Implementing:
      * Implement full hard link functionality.
      * Implement more testcases for testsuite.
      * Implement advanced mini_fo_check_dentry etc...
      * Implement improved error recovery (in order to possibly allow to change lower files some day)

   * Testing:
      * Test exporting a mini_fo file system with nfs.
      * Test extendend attributes.

---+++Development sources
Will be put here.

---+++mini_fo testsuite
The mini_fo testsuite is a set of bash scripts and programs, that perform various tests on a mini_fo file system. Check the README in the sources to find out how to use it and how to write new tests.

[[%ATTACHURL%/mini_fo-testsuite-0-0-3.tar.bz2][mini_fo-testsuite-0-0-3.tar.bz2]]
   * Implemented "rename file to an existing file" test
   * Soft and hard link tests
   * Bonnie performance test (not so much to test performance, but to put some pressure on the fs)

[[%ATTACHURL%/mini_fo-testsuite-0-0-2.tar.bz2][mini_fo-testsuite-0-0-2.tar.bz2]]
   * first release of testsuite supporting testing of most basic operations.




-- Main.MarkusKlotzbuecher - 09 May 2005