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
  33 static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
  34 {
  35         struct dentry *parent = NULL;
  36         struct gfs2_sbd *sdp;
  37         struct gfs2_inode *dip;
  38         struct inode *dinode, *inode;
  39         struct gfs2_holder d_gh;
  40         struct gfs2_inode *ip = NULL;
  41         int error, valid = 0;
  42         int had_lock = 0;
  43
  44         if (flags & LOOKUP_RCU) {
  45                 dinode = d_inode_rcu(READ_ONCE(dentry->d_parent));
  46                 if (!dinode)
  47                         return -ECHILD;
  48         } else {
  49                 parent = dget_parent(dentry);
  50                 dinode = d_inode(parent);
  51         }
  52         sdp = GFS2_SB(dinode);
  53         dip = GFS2_I(dinode);
  54         inode = d_inode(dentry);
  55
  56         if (inode) {
  57                 if (is_bad_inode(inode))
  58                         goto out;
  59                 ip = GFS2_I(inode);
  60         }
  61
  62         if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL) {
  63                 valid = 1;
  64                 goto out;
  65         }
  66
  67         had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  68         if (!had_lock) {
  69                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED,
  70                                            flags & LOOKUP_RCU ? GL_NOBLOCK : 0, &d_gh);
  71                 if (error)
  72                         goto out;
  73         }
  74
  75         error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
  76         valid = inode ? !error : (error == -ENOENT);
  77
  78         if (!had_lock)
  79                 gfs2_glock_dq_uninit(&d_gh);
  80 out:
  81         dput(parent);
  82         return valid;
  83 }
  84
  85 static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
  86 {
  87         str->hash = gfs2_disk_hash(str->name, str->len);
  88         return 0;
  89 }
  90
  91 static int gfs2_dentry_delete(const struct dentry *dentry)
  92 {
  93         struct gfs2_inode *ginode;
  94
  95         if (d_really_is_negative(dentry))
  96                 return 0;
  97
  98         ginode = GFS2_I(d_inode(dentry));
  99         if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
 100                 return 0;
 101
 102         if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 103                 return 1;
 104
 105         return 0;
 106 }
 107
 108 const struct dentry_operations gfs2_dops = {
 109         .d_revalidate = gfs2_drevalidate,
 110         .d_hash = gfs2_dhash,
 111         .d_delete = gfs2_dentry_delete,
 112 };
 113