Re: msdosfs and cd9660: stat(2) returns garbled birthtime

Ulrich Spoerlein wrote:
 > Oliver Fromme wrote:
 > > Please see PR kern/106018.  It fixes the msdosfs case;
 > > it has already been committed a few weeks ago.
 > > 
 > > I haven't looked at the cd9660 code, but if you see
 > > similar problems there, then I guess it needs a similar
 > > fix.  ;-)
 > 
 > Ah, sorry for not testing this on current (I used RELENG_6).

Well, this is the "-current" mailing list, so I assumed
you were using (an older version of) -current a.k.a. HEAD,
not RELENG_6 which is -stable.

I haven't checked whether the patch from kern/106018 has
been MFCed.  Maybe it wasn't deemed safe enough for
inclusion during the 6.2 code freeze (it's a quite trivial
patch, though).

 > Changeing each filesystem code to do this is somewhat ugly.

I don't think it is ugly.  It's up to each file system to
decide which data makes sense to use for the birthtime.

 > Though I
 > don't think that we will grow significantly more statfs fields over
 > time, the syscall should probably first bzero() the struct and let the
 > fs-specific code fill in the/some blanks.

That would mean that zero will be returned for fields that
are not filled in by the FS-specific code.  That's wrong.
In most cases it probably makes more sense to return -1
for unsupported fields, rather than 0.  And in some cases,
a different value should be copied.  (For example, FAT does
not support ctime, but it would be wrong to return 0 or -1
for it.  Instead, the most useful thing to do is copy the
mtime value for the ctime.)

The real fix is to have every FS fill in _all_ fields with
reasonable values.

Best regards
   Oliver

-- 
Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
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