Messages in this thread | | | Date | Wed, 1 Jul 2009 15:17:27 +0100 | From | Alan Cox <> | Subject | Re: [PATCH] Added CONFIG_VFAT_FS_DUALNAMES option |
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> > shouldn't accidentally be able to specify -o vfat and get non-vfat. Thats > > asking for incompatibility, data loss and unpleasant unwarned of suprises. > > There really was no such thing as "vfat" anyway. VFAT in the Windows
In the eyes of the end user there is such a thing as vfat. This is about expectations not technical issues.
> Arguably what we should have done is kept it as a single filesystem, > with a mount options "lfn" and "nolfn", but that's water under the > bridge now.
Well we didn't so now we need to add "lfat" or similar for our fat style. Doesn't need new code just making sure that USSA_COMPLIANCE_MODE=y causes mount -o lfat to work and without it both lfat and vfat work.
> The other big user I can think of are digital cameras, but (a) > normally most users read from them and then delete the pictures, and > rarely write to media meant for a digital camera, and (b) the DCIM
Except when they hit save instead of "save as" and they get a long file name and invisible loss of space on the camera.
> standard for digital cameras explicitly only supports 8.3 filenames > and so digital camera manufacturers explicitly don't need to deal with > Long File Names at all. (Hmm.... I wonder why....)
Can't think - but HAL should clearly mount those 8.3 to avoid the problem. It seems to use the dcim to find them.
> This suggests that some userspace mechanism for detecting media cards > used for cameras and explicitly mounting them with FAT might be useful
HAL is very good at that already.
> Ultimately, though, requiring that every single possible device be > tested is probably not reasonable, so the best way to do this testing > is the way do most of our testing; we do basic due diligence, but then > we merge it into mainline and let our huge user community try it out. > If there are regressions we can work through those issues if and when > they arise.
From the funnies we've had in the past with FAT my gut impression is there are only a few implementations out there. Psion seems to have their own but most of the rest behave remarkably similarly which makes me suspect they all licensed a tiny number of implementations (DRDOS one perhaps ?). If we can keep most of those devices mounted 8.3 we nicely sidestep the issue anyway.
Alan
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