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Is there FUSE overlay filesystem, that: * resolve on it's own "too long filenames" for underlying filesystem * otherwise (for filenames fitting into limits of underlying filesystem) just proxy 1:1 ?

Example how this could work: for each file fabc...yxz having file name too long for given underlying filesystem, translate this into shorter name and use second file as metadata with full filename details.

Use case: Limitation of encrypted filesystems like EncFS or ecryptfs. They provide ability of storing filenames shorter than in underlaying filesystem, when encrypting filenames, resulting that you can not rsync into them contents that require longer filenames. (e.g. Ext4 has 255B, ecryptfs on ext4 allow 143B of filenames).

Example problems rsync reporting:

rsync: mkstemp "/mnt/naswaw2016/ext4/asusm2n1934/enc/home/gwpl/dane/cs/reed-solomon/.CS-05-569 - reed-solomon [vg][vgvg] - Optimizing Cauchy Reed-Solomon Codes for Faul
t-Tolerant Storage Applications - by James S. Plank.pdf.CwyPQH" failed: File name too long (36)

Some references:

(P.S. And yes - I am aware of encrypting on block layer with LUKS, but encrypting above fs layer is so much better to my usecase, that I'd rather prefer stick to it)

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    If the ext4 limits are fine for you, you could use LUKS encryption, or the native encryption that ext4 implements since recently. As for ecryptfs, maybe you could improve it rather than introducing yet another new layer... I wish filesystems supported Unicode characters like NTFS rather than limiting to bytes in this day and age... you get the same problems when rsync from Japanese windows to ext4 because filenames can be longer in Windows when using non-ascii chars... – frostschutz May 14 '16 at 15:06
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    ext4 is not only one, I also use btrfs. ecryptfs provides clean mechanism to apply same encryption configuration for both. And as in question: I prefer overlay fs than LUKS. As you've mentioned, overlay FS for handling "too long filenames" could also address unicode issues as extra functionality. – Grzegorz Wierzowiecki May 14 '16 at 16:27
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    There are some fuse things that do it indirectly, for example, fuse-zip seems to handle files with long names and zips them (and I guess the zip would in turn be encrypted by ecryptfs). But it's probably not what you're looking for (and I don't know one that would do what Joliet/RockRidge is for CDs...) – frostschutz May 14 '16 at 16:51
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    fuse-zip is not what I am looking for, but might work as "temporary workaround" for some directories/applications where I need more than 143 characters :). Thanks for this suggestion! And question remains open :). – Grzegorz Wierzowiecki May 15 '16 at 8:18

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