LXR linux/fs/gfs2/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 * @dentry: the mapping to check
  25 * @flags: lookup flags
  26 *
  27 * Check to make sure the lookup necessary to arrive at this inode from its
  28 * parent is still good.
  29 *
  30 * Returns: 1 if the dentry is ok, 0 if it isn't
  31 */
  32
  33static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
  34{
  35        struct dentry *parent;
  36        struct gfs2_sbd *sdp;
  37        struct gfs2_inode *dip;
  38        struct inode *inode;
  39        struct gfs2_holder d_gh;
  40        struct gfs2_inode *ip = NULL;
  41        int error;
  42        int had_lock = 0;
  43
  44        if (flags & LOOKUP_RCU)
  45                return -ECHILD;
  46
  47        parent = dget_parent(dentry);
  48        sdp = GFS2_SB(d_inode(parent));
  49        dip = GFS2_I(d_inode(parent));
  50        inode = d_inode(dentry);
  51
  52        if (inode) {
  53                if (is_bad_inode(inode))
  54                        goto invalid;
  55                ip = GFS2_I(inode);
  56        }
  57
  58        if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
  59                goto valid;
  60
  61        had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  62        if (!had_lock) {
  63                error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  64                if (error)
  65                        goto fail;
  66        } 
  67
  68        error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
  69        switch (error) {
  70        case 0:
  71                if (!inode)
  72                        goto invalid_gunlock;
  73                break;
  74        case -ENOENT:
  75                if (!inode)
  76                        goto valid_gunlock;
  77                goto invalid_gunlock;
  78        default:
  79                goto fail_gunlock;
  80        }
  81
  82valid_gunlock:
  83        if (!had_lock)
  84                gfs2_glock_dq_uninit(&d_gh);
  85valid:
  86        dput(parent);
  87        return 1;
  88
  89invalid_gunlock:
  90        if (!had_lock)
  91                gfs2_glock_dq_uninit(&d_gh);
  92invalid:
  93        dput(parent);
  94        return 0;
  95
  96fail_gunlock:
  97        gfs2_glock_dq_uninit(&d_gh);
  98fail:
  99        dput(parent);
 100        return 0;
 101}
 102
 103static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
 104{
 105        str->hash = gfs2_disk_hash(str->name, str->len);
 106        return 0;
 107}
 108
 109static int gfs2_dentry_delete(const struct dentry *dentry)
 110{
 111        struct gfs2_inode *ginode;
 112
 113        if (d_really_is_negative(dentry))
 114                return 0;
 115
 116        ginode = GFS2_I(d_inode(dentry));
 117        if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
 118                return 0;
 119
 120        if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 121                return 1;
 122
 123        return 0;
 124}
 125
 126const struct dentry_operations gfs2_dops = {
 127        .d_revalidate = gfs2_drevalidate,
 128        .d_hash = gfs2_dhash,
 129        .d_delete = gfs2_dentry_delete,
 130};
 131
 132