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/*
Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc.
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"
/* Reading and writing of files. this is called by other filesystem
routines and handles extension of files automatically. NP is the
node to be read or written, and must be locked. DATA will be
written or filled. OFF identifies where in thi fel the I/O is to
take place (-1 is not allowed). AMT is the size of DATA and tells
how much to copy. DIR is 1 for writing and 0 for reading. CRED is
the user doing the access (only used to validate attempted file
extension). For reads, *AMTREAD is filled with the amount actually
read. */
error_t
diskfs_node_rdwr (struct node *np,
char *data,
off_t off,
size_t amt,
int dir,
struct protid *cred,
size_t *amtread)
{
error_t err;
iohelp_get_conch (&np->conch);
if (dir)
while (off + amt > np->allocsize)
{
err = diskfs_grow (np, off + amt, cred);
if (err)
return err;
if (np->filemod_reqs)
diskfs_notice_filechange (np, FILE_CHANGED_EXTEND, 0, off + amt);
}
if (off + amt > np->dn_stat.st_size)
{
if (dir)
{
np->dn_stat.st_size = off + amt;
np->dn_set_ctime = 1;
}
else
amt = np->dn_stat.st_size - off;
}
if (amtread)
*amtread = amt;
else
amtread = &amt;
err = _diskfs_rdwr_internal (np, data, off, amtread, dir, 0);
if (*amtread && diskfs_synchronous)
{
if (dir)
diskfs_file_update (np, 1);
else
diskfs_node_update (np, 1);
}
return err;
}
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