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/* Node cache management for NFS client implementation
Copyright (C) 1995, 1996 Free Software Foundation, Inc.
Written by Michael I. Bushnell, p/BSG.
This file is part of the GNU Hurd.
The GNU Hurd 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.
The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include "nfs.h"
#include <string.h>
/* Hash table containing all the nodes currently active. */
#define CACHESIZE 512
static struct node *nodehash [CACHESIZE];
/* Compute and return a hash key for NFS file handle FHANDLE. */
static inline int
hash (void *fhandle)
{
unsigned int h = 0;
int i;
for (i = 0; i < NFS_FHSIZE; i++)
h += ((char *)fhandle)[i];
return h % CACHESIZE;
}
/* Lookup the specified file handle FHANDLE in the hash table. If it
is not present, initialize a new node structure and insert it into
the hash table. Whichever course, a new reference is generated and
the node is returned. */
struct node *
lookup_fhandle (void *fhandle)
{
struct node *np;
struct netnode *nn;
int h = hash (fhandle);
spin_lock (&netfs_node_refcnt_lock);
for (np = nodehash[h]; np; np = np->nn->hnext)
{
if (bcmp (np->nn->handle, fhandle, NFS_FHSIZE) != 0)
continue;
np->references++;
spin_unlock (&netfs_node_refcnt_lock);
mutex_lock (&np->lock);
return np;
}
nn = malloc (sizeof (struct netnode));
bcopy (fhandle, nn->handle, NFS_FHSIZE);
nn->stat_updated = 0;
nn->dtrans = NOT_POSSIBLE;
nn->dead_dir = 0;
nn->dead_name = 0;
np = netfs_make_node (nn);
mutex_lock (&np->lock);
nn->hnext = nodehash[h];
if (nn->hnext)
nn->hnext->nn->hprevp = &nn->hnext;
nn->hprevp = &nodehash[h];
nodehash[h] = np;
spin_unlock (&netfs_node_refcnt_lock);
return np;
}
/* Called by libnetfs when node NP has no more references. (See
<hurd/libnetfs.h> for details. Just clear local state and remove
from the hash table. */
void
netfs_node_norefs (struct node *np)
{
if (np->nn->dead_dir)
{
struct node *dir;
char *name;
np->references++;
spin_unlock (&netfs_node_refcnt_lock);
dir = np->nn->dead_dir;
name = np->nn->dead_name;
np->nn->dead_dir = 0;
np->nn->dead_name = 0;
netfs_nput (np);
mutex_lock (&dir->lock);
netfs_attempt_unlink ((struct netcred *)-1, dir, name);
netfs_nput (dir);
free (name);
/* Caller expects us to leave this locked... */
spin_lock (&netfs_node_refcnt_lock);
}
else
{
*np->nn->hprevp = np->nn->hnext;
if (np->nn->hnext)
np->nn->hnext->nn->hprevp = np->nn->hprevp;
if (np->nn->dtrans == SYMLINK)
free (np->nn->transarg.name);
free (np->nn);
free (np);
}
}
/* Change the file handle used for node NP to be HANDLE. Make sure the
hash table stays up to date. */
void
recache_handle (struct node *np, void *handle)
{
int h;
spin_lock (&netfs_node_refcnt_lock);
*np->nn->hprevp = np->nn->hnext;
if (np->nn->hnext)
np->nn->hnext->nn->hprevp = np->nn->hprevp;
bcopy (handle, np->nn->handle, NFS_FHSIZE);
h = hash (handle);
np->nn->hnext = nodehash[h];
if (np->nn->hnext)
np->nn->hnext->nn->hprevp = &np->nn->hnext;
np->nn->hprevp = &nodehash[h];
spin_unlock (&netfs_node_refcnt_lock);
}
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