Re: ftruncate returning EPERM on vfat filesystem

From: Daniel Phillips (phillips@innominate.de)
Date: Sun Jan 07 2001 - 11:44:54 EST


Alan Cox wrote:
>
> > +
> > + /* FAT cannot truncate to a longer file */
> > + if (attr->ia_valid & ATTR_SIZE) {
> > + if (attr->ia_size > inode->i_size)
> > + return -EPERM;
> > + }
> >
> > error = inode_change_ok(inode, attr);
> > if (error)
> >
> > Can someone tell me if this is the cause of my samba problems, and if
> > so, why this was added and if this is safe to revert?
>
> To stop a case where the fs gets corrupted otherwise. You can change that to
> return 0 which is more correct but most not remove it.
>
> (ftruncate is specified to make the file at most length bytes long, extending
> the file is not a guaranteed side effect according to the docs I have)

Speaking as an old time dos hacker, this is allowed and commonly done.
I wouldn't read too much into the fact that it's not documented. :-)
As I recall, new clusters are allocated but not cleared.

--
Daniel
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