dentry.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  4 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  5 */
  6
  7#include <linux/spinlock.h>
  8#include <linux/completion.h>
  9#include <linux/buffer_head.h>
 10#include <linux/gfs2_ondisk.h>
 11#include <linux/namei.h>
 12#include <linux/crc32.h>
 13
 14#include "gfs2.h"
 15#include "incore.h"
 16#include "dir.h"
 17#include "glock.h"
 18#include "super.h"
 19#include "util.h"
 20#include "inode.h"
 21
 22/**
 23 * gfs2_drevalidate - Check directory lookup consistency
 24 * @dir: expected parent directory inode
 25 * @name: expexted name
 26 * @dentry: dentry to check
 27 * @flags: lookup flags
 28 *
 29 * Check to make sure the lookup necessary to arrive at this inode from its
 30 * parent is still good.
 31 *
 32 * Returns: 1 if the dentry is ok, 0 if it isn't
 33 */
 34
 35static int gfs2_drevalidate(struct inode *dir, const struct qstr *name,
 36			    struct dentry *dentry, unsigned int flags)
 37{
 38	struct gfs2_sbd *sdp = GFS2_SB(dir);
 39	struct gfs2_inode *dip = GFS2_I(dir);
 40	struct inode *inode;
 41	struct gfs2_holder d_gh;
 42	struct gfs2_inode *ip = NULL;
 43	int error, valid;
 44	int had_lock = 0;
 45
 46	if (flags & LOOKUP_RCU)
 47		return -ECHILD;
 48
 49	inode = d_inode(dentry);
 50
 51	if (inode) {
 52		if (is_bad_inode(inode))
 53			return 0;
 54		ip = GFS2_I(inode);
 55	}
 56
 57	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
 58		return 1;
 59
 60	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
 61	if (!had_lock) {
 62		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
 63		if (error)
 64			return 0;
 65	}
 66
 67	error = gfs2_dir_check(dir, name, ip);
 68	valid = inode ? !error : (error == -ENOENT);
 69
 70	if (!had_lock)
 71		gfs2_glock_dq_uninit(&d_gh);
 72	return valid;
 73}
 74
 75static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
 76{
 77	str->hash = gfs2_disk_hash(str->name, str->len);
 78	return 0;
 79}
 80
 81static int gfs2_dentry_delete(const struct dentry *dentry)
 82{
 83	struct gfs2_inode *ginode;
 84
 85	if (d_really_is_negative(dentry))
 86		return 0;
 87
 88	ginode = GFS2_I(d_inode(dentry));
 89	if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
 90		return 0;
 91
 92	if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 93		return 1;
 94
 95	return 0;
 96}
 97
 98const struct dentry_operations gfs2_dops = {
 99	.d_revalidate = gfs2_drevalidate,
100	.d_hash = gfs2_dhash,
101	.d_delete = gfs2_dentry_delete,
102};
103