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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 <string.h>
/* Actually read or write a file. The file size must already permit
the requested access. NP is the file to read/write. DATA is a buffer
to write from or fill on read. OFFSET is the absolute address (-1
not permitted here); AMT is the size of the read/write to perform;
DIR is set for writing and clear for reading. The inode must
be locked. */
error_t
_diskfs_rdwr_internal (struct node *np,
char *volatile data,
volatile int offset,
volatile int amt,
int dir)
{
char *window;
int winoff;
volatile int cc;
memory_object_t memobj;
int err = 0;
if (dir)
assert (!diskfs_readonly);
if (!diskfs_readonly)
{
if (dir)
np->dn_set_mtime = 1;
else
np->dn_set_atime = 1;
}
memobj = diskfs_get_filemap (np);
while (amt > 0)
{
winoff = trunc_page (offset);
window = 0;
/* We map in 8 pages at a time. Where'd that come from? Well, the
vax has a 1024 pagesize and with 8k blocks that seems like a
reasonable number. */
err = vm_map (mach_task_self (), (u_int *)&window, 8 * __vm_page_size,
0, 1, memobj, winoff, 0, VM_PROT_READ|VM_PROT_WRITE,
VM_PROT_READ|VM_PROT_WRITE, VM_INHERIT_NONE);
assert (!err);
diskfs_register_memory_fault_area (diskfs_get_filemap_pager_struct (np),
winoff, window, 8 * __vm_page_size);
if ((offset - winoff) + amt > 8 * __vm_page_size)
cc = 8 * __vm_page_size - (offset - winoff);
else
cc = amt;
if (!(err = diskfs_catch_exception ()))
{
if (dir)
bcopy (data, window + (offset - winoff), cc);
else
bcopy (window + (offset - winoff), data, cc);
diskfs_end_catch_exception ();
}
vm_deallocate (mach_task_self (), (u_int) window, 8 * __vm_page_size);
diskfs_unregister_memory_fault_area (window, 8 * __vm_page_size);
if (err)
break;
amt -= cc;
offset += cc;
data += cc;
}
assert (amt == 0 || err);
if (!diskfs_readonly)
{
if (dir)
np->dn_set_mtime = 1;
else
np->dn_set_atime = 1;
}
mach_port_deallocate (mach_task_self (), memobj);
return err;
}
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