vfs_dentry.c
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/*
* linux/fs/9p/vfs_dentry.c
*
* This file contians vfs dentry ops for the 9P2000 protocol.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* 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 of the License, 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:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/inet.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "v9fs_vfs.h"
#include "conv.h"
#include "fid.h"
/**
* v9fs_dentry_validate - VFS dcache hook to validate cache
* @dentry: dentry that is being validated
* @nd: path data
*
* dcache really shouldn't be used for 9P2000 as at all due to
* potential attached semantics to directory traversal (walk).
*
* FUTURE: look into how to use dcache to allow multi-stage
* walks in Plan 9 & potential for better dcache operation which
* would remain valid for Plan 9 semantics. Older versions
* had validation via stat for those interested. However, since
* stat has the same approximate overhead as walk there really
* is no difference. The only improvement would be from a
* time-decay cache like NFS has and that undermines the
* synchronous nature of 9P2000.
*
*/
static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
{
struct dentry *dc = current->fs->pwd;
dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
if (v9fs_fid_lookup(dentry)) {
dprintk(DEBUG_VFS, "VALID\n");
return 1;
}
while (dc != NULL) {
if (dc == dentry) {
dprintk(DEBUG_VFS, "VALID\n");
return 1;
}
if (dc == dc->d_parent)
break;
dc = dc->d_parent;
}
dprintk(DEBUG_VFS, "INVALID\n");
return 0;
}
/**
* v9fs_dentry_release - called when dentry is going to be freed
* @dentry: dentry that is being release
*
*/
void v9fs_dentry_release(struct dentry *dentry)
{
dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
if (dentry->d_fsdata != NULL) {
struct list_head *fid_list = dentry->d_fsdata;
struct v9fs_fid *temp = NULL;
struct v9fs_fid *current_fid = NULL;
struct v9fs_fcall *fcall = NULL;
list_for_each_entry_safe(current_fid, temp, fid_list, list) {
if (v9fs_t_clunk
(current_fid->v9ses, current_fid->fid, &fcall))
dprintk(DEBUG_ERROR, "clunk failed: %s\n",
FCALL_ERROR(fcall));
v9fs_put_idpool(current_fid->fid,
¤t_fid->v9ses->fidpool);
kfree(fcall);
v9fs_fid_destroy(current_fid);
}
kfree(dentry->d_fsdata); /* free the list_head */
}
}
struct dentry_operations v9fs_dentry_operations = {
.d_revalidate = v9fs_dentry_validate,
.d_release = v9fs_dentry_release,
};