Return an error when encountering corrupted lfn entry

[aurelj]

Without this, on a corrupted fs, I get hundreds of "corrupted lfn entry!" messages printed thru defmt for a single read_dir_entry() call.

[MabezDev]

Hmm, I'm not so sure about this change.

CorruptedFileSystem should only be returned when something critical to the operation of the FS has gone wrong, either the boot sector is corrupted or fsinfo is. Imo corruption of a single file or in this case file name entry is not a reason to return this error.

Do defmt logs really matter that much? IIRC I think there is a way to disable defmt logs for a certain crate module: https://defmt.ferrous-systems.com/filtering.html.

[aurelj]

Indeed, I agree CorruptedFileSystem is probably not an appropriate error for this.

But filtering defmt logs sounds a bit hacky and adds the risk of missing some other unrelated and important messages.

process() is only called by DirIter.next() which already return errors in various situations, so it really seems logical that in case of corrupted lfn entry, DirIter.next() returns some kind of error.
So I propose adding a new Error enum value for this situation, such as CorruptedFileEntry.
Does it sound better to you ?