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/* Node cache management for NFS client implementation
Copyright (C) 1995, 1996, 1997 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>
#include <netinet/in.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 DATA of LEN bytes. */
static inline int
hash (int *data, size_t len)
{
unsigned int h = 0;
char *cp = (char *)data;
int i;
for (i = 0; i < len; i++)
h += cp[i];
return h % CACHESIZE;
}
/* Lookup the file handle P (length LEN) 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 in *NPP. */
void
lookup_fhandle (void *p, size_t len, struct node **npp)
{
struct node *np;
struct netnode *nn;
int h;
h = hash (p, len);
spin_lock (&netfs_node_refcnt_lock);
for (np = nodehash[h]; np; np = np->nn->hnext)
{
if (np->nn->handle.size != len
|| bcmp (np->nn->handle.data, p, len) != 0)
continue;
np->references++;
spin_unlock (&netfs_node_refcnt_lock);
mutex_lock (&np->lock);
*npp = np;
return;
}
nn = malloc (sizeof (struct netnode));
nn->handle.size = len;
bcopy (p, nn->handle.data, len);
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);
*npp = np;
}
/* Package holding args to forked_node_delete. */
struct fnd
{
struct node *dir;
char *name;
};
/* Worker function to delete nodes that don't have any more local references
or links. */
any_t
forked_node_delete (any_t arg)
{
struct fnd *args = arg;
mutex_lock (&args->dir->lock);
netfs_attempt_unlink ((struct iouser *)-1, args->dir, args->name);
netfs_nput (args->dir);
free (args->name);
free (args);
return 0;
};
/* 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 fnd *args;
args = malloc (sizeof (struct fnd));
np->references++;
spin_unlock (&netfs_node_refcnt_lock);
args->dir = np->nn->dead_dir;
args->name = np->nn->dead_name;
np->nn->dead_dir = 0;
np->nn->dead_name = 0;
netfs_nput (np);
/* Do this in a separate thread so that we don't wait for it;
it acquires a lock on the dir, which we are not allowed to do. */
cthread_detach (cthread_fork (forked_node_delete, (any_t) args));
/* 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 the handle at P.
Make sure the hash table stays up to date. Return the address
after the hnadle. */
int *
recache_handle (int *p, struct node *np)
{
int h;
size_t len;
if (protocol_version == 2)
len = NFS2_FHSIZE;
else
len = ntohl (*p++);
spin_lock (&netfs_node_refcnt_lock);
*np->nn->hprevp = np->nn->hnext;
if (np->nn->hnext)
np->nn->hnext->nn->hprevp = np->nn->hprevp;
np->nn->handle.size = len;
bcopy (p, np->nn->handle.data, len);
h = hash (p, len);
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);
return p + len / sizeof (int);
}
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