LXR linux/fs/9p/vfs

   1/*
   2 *  linux/fs/9p/vfs_dentry.c
   3 *
   4 * This file contians vfs dentry ops for the 9P2000 protocol.
   5 *
   6 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8 *
   9 *  This program is free software; you can redistribute it and/or modify
  10 *  it under the terms of the GNU General Public License version 2
  11 *  as published by the Free Software Foundation.
  12 *
  13 *  This program is distributed in the hope that it will be useful,
  14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 *  GNU General Public License for more details.
  17 *
  18 *  You should have received a copy of the GNU General Public License
  19 *  along with this program; if not, write to:
  20 *  Free Software Foundation
  21 *  51 Franklin Street, Fifth Floor
  22 *  Boston, MA  02111-1301  USA
  23 *
  24 */
  25
  26#include <linux/module.h>
  27#include <linux/errno.h>
  28#include <linux/fs.h>
  29#include <linux/file.h>
  30#include <linux/pagemap.h>
  31#include <linux/stat.h>
  32#include <linux/string.h>
  33#include <linux/inet.h>
  34#include <linux/namei.h>
  35#include <linux/idr.h>
  36#include <linux/sched.h>
  37#include <linux/slab.h>
  38#include <net/9p/9p.h>
  39#include <net/9p/client.h>
  40
  41#include "v9fs.h"
  42#include "v9fs_vfs.h"
  43#include "fid.h"
  44
  45/**
  46 * v9fs_cached_dentry_delete - called when dentry refcount equals 0
  47 * @dentry:  dentry in question
  48 *
  49 */
  50static int v9fs_cached_dentry_delete(const struct dentry *dentry)
  51{
  52        p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  53                 dentry, dentry);
  54
  55        /* Don't cache negative dentries */
  56        if (d_really_is_negative(dentry))
  57                return 1;
  58        return 0;
  59}
  60
  61/**
  62 * v9fs_dentry_release - called when dentry is going to be freed
  63 * @dentry:  dentry that is being release
  64 *
  65 */
  66
  67static void v9fs_dentry_release(struct dentry *dentry)
  68{
  69        struct hlist_node *p, *n;
  70        p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  71                 dentry, dentry);
  72        hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
  73                p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
  74        dentry->d_fsdata = NULL;
  75}
  76
  77static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
  78{
  79        struct p9_fid *fid;
  80        struct inode *inode;
  81        struct v9fs_inode *v9inode;
  82
  83        if (flags & LOOKUP_RCU)
  84                return -ECHILD;
  85
  86        inode = d_inode(dentry);
  87        if (!inode)
  88                goto out_valid;
  89
  90        v9inode = V9FS_I(inode);
  91        if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
  92                int retval;
  93                struct v9fs_session_info *v9ses;
  94                fid = v9fs_fid_lookup(dentry);
  95                if (IS_ERR(fid))
  96                        return PTR_ERR(fid);
  97
  98                v9ses = v9fs_inode2v9ses(inode);
  99                if (v9fs_proto_dotl(v9ses))
 100                        retval = v9fs_refresh_inode_dotl(fid, inode);
 101                else
 102                        retval = v9fs_refresh_inode(fid, inode);
 103                if (retval == -ENOENT)
 104                        return 0;
 105                if (retval < 0)
 106                        return retval;
 107        }
 108out_valid:
 109        return 1;
 110}
 111
 112const struct dentry_operations v9fs_cached_dentry_operations = {
 113        .d_revalidate = v9fs_lookup_revalidate,
 114        .d_weak_revalidate = v9fs_lookup_revalidate,
 115        .d_delete = v9fs_cached_dentry_delete,
 116        .d_release = v9fs_dentry_release,
 117};
 118
 119const struct dentry_operations v9fs_dentry_operations = {
 120        .d_delete = always_delete_dentry,
 121        .d_release = v9fs_dentry_release,
 122};
 123