dentry.c

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/namei.h>
#include <linux/crc32.h>

#include "gfs2.h"
#include "incore.h"
#include "dir.h"
#include "glock.h"
#include "super.h"
#include "util.h"
#include "inode.h"

static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
{
    struct dentry *parent;
    struct gfs2_sbd *sdp;
    struct gfs2_inode *dip;
    struct inode *inode;
    struct gfs2_holder d_gh;
    struct gfs2_inode *ip = NULL;
    int error;
    int had_lock = 0;

    if (flags & LOOKUP_RCU)
        return -ECHILD;

    parent = dget_parent(dentry);
    sdp = GFS2_SB(parent->d_inode);
    dip = GFS2_I(parent->d_inode);
    inode = dentry->d_inode;

    if (inode) {
        if (is_bad_inode(inode))
            goto invalid;
        ip = GFS2_I(inode);
    }

    if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
        goto valid;

    had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
    if (!had_lock) {
        error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
        if (error)
            goto fail;
    } 

    error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);
    switch (error) {
    case 0:
        if (!inode)
            goto invalid_gunlock;
        break;
    case -ENOENT:
        if (!inode)
            goto valid_gunlock;
        goto invalid_gunlock;
    default:
        goto fail_gunlock;
    }

valid_gunlock:
    if (!had_lock)
        gfs2_glock_dq_uninit(&d_gh);
valid:
    dput(parent);
    return 1;

invalid_gunlock:
    if (!had_lock)
        gfs2_glock_dq_uninit(&d_gh);
invalid:
    if (inode && S_ISDIR(inode->i_mode)) {
        if (have_submounts(dentry))
            goto valid;
        shrink_dcache_parent(dentry);
    }
    d_drop(dentry);
    dput(parent);
    return 0;

fail_gunlock:
    gfs2_glock_dq_uninit(&d_gh);
fail:
    dput(parent);
    return 0;
}

static int gfs2_dhash(const struct dentry *dentry, const struct inode *inode,
        struct qstr *str)
{
    str->hash = gfs2_disk_hash(str->name, str->len);
    return 0;
}

static int gfs2_dentry_delete(const struct dentry *dentry)
{
    struct gfs2_inode *ginode;

    if (!dentry->d_inode)
        return 0;

    ginode = GFS2_I(dentry->d_inode);
    if (!ginode->i_iopen_gh.gh_gl)
        return 0;

    if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
        return 1;

    return 0;
}

const struct dentry_operations gfs2_dops = {
    .d_revalidate = gfs2_drevalidate,
    .d_hash = gfs2_dhash,
    .d_delete = gfs2_dentry_delete,
};