linux/fs/9p/vfs_dentry.c
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   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_dentry_delete - called when dentry refcount equals 0
  47 * @dentry:  dentry in question
  48 *
  49 * By returning 1 here we should remove cacheing of unused
  50 * dentry components.
  51 *
  52 */
  53
  54static int v9fs_dentry_delete(const struct dentry *dentry)
  55{
  56        p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  57                 dentry->d_name.name, dentry);
  58
  59        return 1;
  60}
  61
  62/**
  63 * v9fs_cached_dentry_delete - called when dentry refcount equals 0
  64 * @dentry:  dentry in question
  65 *
  66 */
  67static int v9fs_cached_dentry_delete(const struct dentry *dentry)
  68{
  69        p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  70                 dentry->d_name.name, dentry);
  71
  72        /* Don't cache negative dentries */
  73        if (!dentry->d_inode)
  74                return 1;
  75        return 0;
  76}
  77
  78/**
  79 * v9fs_dentry_release - called when dentry is going to be freed
  80 * @dentry:  dentry that is being release
  81 *
  82 */
  83
  84static void v9fs_dentry_release(struct dentry *dentry)
  85{
  86        struct hlist_node *p, *n;
  87        p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  88                 dentry->d_name.name, dentry);
  89        hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
  90                p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
  91        dentry->d_fsdata = NULL;
  92}
  93
  94static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
  95{
  96        struct p9_fid *fid;
  97        struct inode *inode;
  98        struct v9fs_inode *v9inode;
  99
 100        if (flags & LOOKUP_RCU)
 101                return -ECHILD;
 102
 103        inode = dentry->d_inode;
 104        if (!inode)
 105                goto out_valid;
 106
 107        v9inode = V9FS_I(inode);
 108        if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
 109                int retval;
 110                struct v9fs_session_info *v9ses;
 111                fid = v9fs_fid_lookup(dentry);
 112                if (IS_ERR(fid))
 113                        return PTR_ERR(fid);
 114
 115                v9ses = v9fs_inode2v9ses(inode);
 116                if (v9fs_proto_dotl(v9ses))
 117                        retval = v9fs_refresh_inode_dotl(fid, inode);
 118                else
 119                        retval = v9fs_refresh_inode(fid, inode);
 120                if (retval == -ENOENT)
 121                        return 0;
 122                if (retval < 0)
 123                        return retval;
 124        }
 125out_valid:
 126        return 1;
 127}
 128
 129const struct dentry_operations v9fs_cached_dentry_operations = {
 130        .d_revalidate = v9fs_lookup_revalidate,
 131        .d_weak_revalidate = v9fs_lookup_revalidate,
 132        .d_delete = v9fs_cached_dentry_delete,
 133        .d_release = v9fs_dentry_release,
 134};
 135
 136const struct dentry_operations v9fs_dentry_operations = {
 137        .d_delete = v9fs_dentry_delete,
 138        .d_release = v9fs_dentry_release,
 139};
 140
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