Re: ext2/3 subdirectory limit [WAS: Choosing and tuning Linux file systems]

["H. Peter Anvin" <hpa@zytor.com>]

Chris Wedgwood wrote:
> 
>> As Ted said, not all fiel systems follow this. This means that such
>> applications cannot e.g., remove a directory (rm -r) from such a FS?
> 
> i don't know about rm, but some versions of find need -noleaf (see the
> man page for details)
> 
>> I am asking because we have an issue that an older version of mc
>> cannot remove directory recursively, however we have not observed
>> this on any new system. Might the nlink count be the problem?
> 
> i'm not seen the nlink problem occur because pretty much all
> filesystems have nlink set correctly *or* they set it to one like
> autofs does which happens to work because 1-2-n underflows (there are
> also those who claim that nlink==1 implies you don't know how many
> links there are)

Right.  On most applications, it "just works" because of underflow (if 
you treat nlink as unsigned and subtract 2, then you get UINT_MAX which 
is functionally infinity.)  This is a good reason for this particular 
retcon.

The established practice is to set nlink to 1 if either you don't know 
how many links there are or there are too many to fit in the nlink field.

	-hpa