Re: [PATCH 1/5] fallocate() implementation in i86, x86_64 and powerpc

David Chinner
2007-05-04T06:08:13Z

On Thu, May 03, 2007 at 09:29:55PM -0700, Andrew Morton wrote:
> On Thu, 26 Apr 2007 23:33:32 +0530 "Amit K. Arora" <aarora@linux.vnet.ibm.com> wrote:
>
> > This patch implements the fallocate() system call and adds support for
> > i386, x86_64 and powerpc.
> >
> > ...
> > +{
> > + struct file *file;
> > + struct inode *inode;
> > + long ret = -EINVAL;
> > +
> > + if (len == 0 || offset < 0)
> > + goto out;
>
> The posix spec implies that negative `len' is permitted - presumably "allocate
> ahead of `offset'". How peculiar.

I just checked the man page for posix_fallocate() and it says:

EINVAL offset or len was less than zero.

We should probably follow this lead.

> > +
> > + ret = -ENODEV;
> > + if (!S_ISREG(inode->i_mode))
> > + goto out_fput;
>
> So we return ENODEV against an S_ISBLK fd, as per the posix spec. That
> seems a bit silly of them.

Hmmmm - I thought that the intention of sys_fallocate() was to
be generic enough to eventually allow preallocation on directories.
If that is the case, then this check will prevent that....

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group