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/*
Copyright (C) 1994 Free Software Foundation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "priv.h"
#include "io_S.h"
/* Implement io_prenotify as described in <hurd/io.defs>.
We set the prenotify size to be the allocated size of the file;
then users are forced to call this routine before writing past
that, and we can do allocation (orreturn ENOSPC if necessary. */
error_t
diskfs_S_io_prenotify (struct protid *cred,
int start,
int end)
{
struct node *np;
int err = 0;
if (!cred)
return EOPNOTSUPP;
np = cred->po->np;
/* Clamp it down */
mutex_lock (&np->lock);
if (!cred->mapped)
{
err = EINVAL;
goto out;
}
err = ioserver_verify_user_conch (&np->conch, cred);
if (err)
goto out;
ioserver_fetch_shared_data (cred);
if (end < np->allocsize)
{
/* The user is either foolin' with us, or has the wrong
prenotify size, hence the diagnostic. */
printf ("io_prenotify: unnecessary call\n");
spin_lock (&cred->mapped->lock);
err = ioserver_put_shared_data (cred);
spin_unlock (&cred->mapped->lock);
goto out;
}
err = diskfs_grow (np, end, cred);
out:
mutex_unlock (&np->i_toplock);
return err;
}
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