LXR linux/fs/gfs2/dentry.c

   1/*
   2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4 *
   5 * This copyrighted material is made available to anyone wishing to use,
   6 * modify, copy, or redistribute it subject to the terms and conditions
   7 * of the GNU General Public License version 2.
   8 */
   9
  10#include <linux/slab.h>
  11#include <linux/spinlock.h>
  12#include <linux/completion.h>
  13#include <linux/buffer_head.h>
  14#include <linux/gfs2_ondisk.h>
  15#include <linux/crc32.h>
  16
  17#include "gfs2.h"
  18#include "incore.h"
  19#include "dir.h"
  20#include "glock.h"
  21#include "super.h"
  22#include "util.h"
  23#include "inode.h"
  24
  25/**
  26 * gfs2_drevalidate - Check directory lookup consistency
  27 * @dentry: the mapping to check
  28 * @nd:
  29 *
  30 * Check to make sure the lookup necessary to arrive at this inode from its
  31 * parent is still good.
  32 *
  33 * Returns: 1 if the dentry is ok, 0 if it isn't
  34 */
  35
  36static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  37{
  38        struct dentry *parent = dget_parent(dentry);
  39        struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
  40        struct gfs2_inode *dip = GFS2_I(parent->d_inode);
  41        struct inode *inode = dentry->d_inode;
  42        struct gfs2_holder d_gh;
  43        struct gfs2_inode *ip = NULL;
  44        int error;
  45        int had_lock = 0;
  46
  47        if (inode) {
  48                if (is_bad_inode(inode))
  49                        goto invalid;
  50                ip = GFS2_I(inode);
  51        }
  52
  53        if (sdp->sd_args.ar_localcaching)
  54                goto valid;
  55
  56        had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  57        if (!had_lock) {
  58                error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  59                if (error)
  60                        goto fail;
  61        } 
  62
  63        error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);
  64        switch (error) {
  65        case 0:
  66                if (!inode)
  67                        goto invalid_gunlock;
  68                break;
  69        case -ENOENT:
  70                if (!inode)
  71                        goto valid_gunlock;
  72                goto invalid_gunlock;
  73        default:
  74                goto fail_gunlock;
  75        }
  76
  77valid_gunlock:
  78        if (!had_lock)
  79                gfs2_glock_dq_uninit(&d_gh);
  80valid:
  81        dput(parent);
  82        return 1;
  83
  84invalid_gunlock:
  85        if (!had_lock)
  86                gfs2_glock_dq_uninit(&d_gh);
  87invalid:
  88        if (inode && S_ISDIR(inode->i_mode)) {
  89                if (have_submounts(dentry))
  90                        goto valid;
  91                shrink_dcache_parent(dentry);
  92        }
  93        d_drop(dentry);
  94        dput(parent);
  95        return 0;
  96
  97fail_gunlock:
  98        gfs2_glock_dq_uninit(&d_gh);
  99fail:
 100        dput(parent);
 101        return 0;
 102}
 103
 104static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 105{
 106        str->hash = gfs2_disk_hash(str->name, str->len);
 107        return 0;
 108}
 109
 110static int gfs2_dentry_delete(struct dentry *dentry)
 111{
 112        struct gfs2_inode *ginode;
 113
 114        if (!dentry->d_inode)
 115                return 0;
 116
 117        ginode = GFS2_I(dentry->d_inode);
 118        if (!ginode->i_iopen_gh.gh_gl)
 119                return 0;
 120
 121        if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 122                return 1;
 123
 124        return 0;
 125}
 126
 127const struct dentry_operations gfs2_dops = {
 128        .d_revalidate = gfs2_drevalidate,
 129        .d_hash = gfs2_dhash,
 130        .d_delete = gfs2_dentry_delete,
 131};
 132
 133