On 07/21/2009 06:37 AM, tridge@xxxxxxxxx wrote: > Thanks to everyone who helped with the testing of the previous round > of VFAT patent workaround patches. > > I've posted a new set of patches today which tries to address some of > the technical problems found in the last patch. > > The new patches: > > - work with Win98 > - work with Jan's IOneIt MP3 player > - work with all the other FAT capable devices I have available for > testing > - work with existing copies of mtools > > The remaining issues that I am aware of are: > > - There is a cosmetic issue with the DOS command prompt under > Win98. A directory listing works, but displays garbage in the > column where a 8.3 short filename would normally go > > - Similarly, under WinXP, a "dir/x" will show garbage in the 8.3 > column. For example: http://samba.org/~tridge/dir_test.png > I guess you tried putting a zero at first char and it breaks everybody? > - mtools has a similar cosmetic issue, which is fixed with a small > patch > > - devices which only support 8.3 filenames will not be able to see > or use files created with long names with the patch enabled > > - There is a very small chance of WinXP bluescreening if two files > in the same directory have the same 11 dummy bytes, and are > accessed in quick succession. The chances of this happening is > approximately 80x smaller than with the previous patch. As > previously noted, this is a very difficult problem to reproduce, > and in fact nobody has managed to reproduce it without modifying > the patch to use a much smaller number of random bits. > I guess (35^6)*8*7 is not that bad > - Similarly, there is a small chance that chkdsk on Windows will > rename one file in a directory if they happen to have the same 11 > byte dummy values. The probability of this happening is > approximately 80x lower than with the previous patch. > What if we had a user mode utility that does these short-names renames that a user can optionally run after umount? since it only writes the (random) short-names it's also safe. Kind of the cop that can read and the cop that can write e-literacy problem, No? > Some people have also asked that this patch change the name of the > filesystem to 'lfat' or similar. I have not included that change in > this patch as I think it is counter productive. Instead I have added a > printk_once() to produce a warning like this: > > VFAT: not creating 8.3 short filenames for long names > > when the first long filename is created on a VFAT filesystem with this > patch enabled. > > The reason I think this is a better option than a filesystem name > change is that a name change will break a unknown number of userspace > tools, scripts and config files. For example, desktop tools for > mounting filesystems, scripts that use -t vfat, module configuration > options in /etc could all be broken without any ability to give the > user feedback on why it broke. > > If you have a FAT capable device that you want to test for > compatibility with the new patches, please have a look at the > 'Testing' section of the following README: > > http://kernel.org/pub/linux/kernel/people/tridge/VFAT/README > > It gives details on how you can do testing without having to change > your kernel. > > Cheers, Tridge > -- Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
