Re: [PATCH] Doc fix: ext2 can only have 32,000 subdirs, not 32,768.

[Andrew Morton <akpm@linux-foundation.org>]

On Sat, 30 May 2009 13:37:24 +0200 Pavel Machek <pavel@ucw.cz> wrote:

> On Wed 2009-05-27 17:20:45, Andrew Morton wrote:
> > On Mon, 18 May 2009 12:13:51 -0700
> > Michael Shields <mshields@google.com> wrote:
> > 
> > > ext2.txt says that dirs can have 32,768 subdirs, but the actual value
> > > of EXT2_LINK_MAX is 32000.
> > > ext3 is the same, but the doc does not mention it. __One of ext4's
> > > features is to "fix 32000 subdirectory limit".
> > > 
> > > --- linux-2.6.29.3/Documentation/filesystems/ext2.txt.orig 2009-05-08
> > > 15:47:21.000000000 -0700
> > > +++ linux-2.6.29.3/Documentation/filesystems/ext2.txt 2009-05-18
> > > 12:03:58.000000000 -0700
> > > @@ -322,7 +322,7 @@ an upper limit on the block size imposed
> > > __so 8kB blocks are only allowed on Alpha systems (and other architectures
> > > __which support larger pages).
> > > 
> > > -There is an upper limit of 32768 subdirectories in a single directory.
> > > +There is an upper limit of 32000 subdirectories in a single directory.
> > > 
> > > __There is a "soft" upper limit of about 10-15k files in a single directory
> > > __with the current linear linked-list directory implementation. __This limit
> > > --
> 
> Maybe it would be better to increase EXT2_LINK_MAX to fit the docs?
> 

Could be.  afacit filesystems which are created under such a driver
will still mount and work OK with older drivers.

I have this vague memory that there was a reason for the 32000 thing.