linux/fs/gfs2/dentry.c
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   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/spinlock.h>
  11#include <linux/completion.h>
  12#include <linux/buffer_head.h>
  13#include <linux/gfs2_ondisk.h>
  14#include <linux/namei.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 * @flags: lookup flags
  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, unsigned int flags)
  37{
  38        struct dentry *parent;
  39        struct gfs2_sbd *sdp;
  40        struct gfs2_inode *dip;
  41        struct inode *inode;
  42        struct gfs2_holder d_gh;
  43        struct gfs2_inode *ip = NULL;
  44        int error;
  45        int had_lock = 0;
  46
  47        if (flags & LOOKUP_RCU)
  48                return -ECHILD;
  49
  50        parent = dget_parent(dentry);
  51        sdp = GFS2_SB(parent->d_inode);
  52        dip = GFS2_I(parent->d_inode);
  53        inode = dentry->d_inode;
  54
  55        if (inode) {
  56                if (is_bad_inode(inode))
  57                        goto invalid;
  58                ip = GFS2_I(inode);
  59        }
  60
  61        if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
  62                goto valid;
  63
  64        had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  65        if (!had_lock) {
  66                error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  67                if (error)
  68                        goto fail;
  69        } 
  70
  71        error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);
  72        switch (error) {
  73        case 0:
  74                if (!inode)
  75                        goto invalid_gunlock;
  76                break;
  77        case -ENOENT:
  78                if (!inode)
  79                        goto valid_gunlock;
  80                goto invalid_gunlock;
  81        default:
  82                goto fail_gunlock;
  83        }
  84
  85valid_gunlock:
  86        if (!had_lock)
  87                gfs2_glock_dq_uninit(&d_gh);
  88valid:
  89        dput(parent);
  90        return 1;
  91
  92invalid_gunlock:
  93        if (!had_lock)
  94                gfs2_glock_dq_uninit(&d_gh);
  95invalid:
  96        if (inode && S_ISDIR(inode->i_mode)) {
  97                if (have_submounts(dentry))
  98                        goto valid;
  99                shrink_dcache_parent(dentry);
 100        }
 101        d_drop(dentry);
 102        dput(parent);
 103        return 0;
 104
 105fail_gunlock:
 106        gfs2_glock_dq_uninit(&d_gh);
 107fail:
 108        dput(parent);
 109        return 0;
 110}
 111
 112static int gfs2_dhash(const struct dentry *dentry, const struct inode *inode,
 113                struct qstr *str)
 114{
 115        str->hash = gfs2_disk_hash(str->name, str->len);
 116        return 0;
 117}
 118
 119static int gfs2_dentry_delete(const struct dentry *dentry)
 120{
 121        struct gfs2_inode *ginode;
 122
 123        if (!dentry->d_inode)
 124                return 0;
 125
 126        ginode = GFS2_I(dentry->d_inode);
 127        if (!ginode->i_iopen_gh.gh_gl)
 128                return 0;
 129
 130        if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 131                return 1;
 132
 133        return 0;
 134}
 135
 136const struct dentry_operations gfs2_dops = {
 137        .d_revalidate = gfs2_drevalidate,
 138        .d_hash = gfs2_dhash,
 139        .d_delete = gfs2_dentry_delete,
 140};
 141
 142
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