Re: Msdos name alias patch for 2.1.48

Ingo Molnar (
Thu, 7 Aug 1997 20:00:22 +0200 (MET DST)

On Thu, 7 Aug 1997, Ingo Molnar wrote:

> Another thing apart speed issues is that this might confuse applications
> which assume that say sys_readdir() gives canonical names? Or, maybe more
> important, assumes that they never change. With this solution the name
> passed back might be different from case to case.

tar made on a DOS filesystem might get confused? It stores filenames as
they come, and if someone wants to extract a certain file, based on the
name just being seen, it wont work. (well, if this is a problem)

even if nothing breaks by some miracle :), it's a quality of
implementation issue i think.

What about the following solution to the 'alias names' problem:

- an optional per-filesystem 'import_string_from_user()' operation. This
would copy&translate name strings to a canonical form. On most CPUs this
would be nicely pipelined and thus the translation cost would be almost
zero. [we always copy from user-space first anyway]

So we always have an 'internal representation' that fits everything. The
dentry code knows nothing about this alias problem. No complexity in the
lookup itself. [Also, we could use an 'export' function too, for symbolic
links? unsure.]

-- mingo