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;
  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
  82 valid_gunlock:
  83         if (!had_lock)
  84                 gfs2_glock_dq_uninit(&d_gh);
  85 valid:
  86         dput(parent);
  87         return 1;
  88
  89 invalid_gunlock:
  90         if (!had_lock)
  91                 gfs2_glock_dq_uninit(&d_gh);
  92 invalid:
  93         dput(parent);
  94         return 0;
  95
  96 fail_gunlock:
  97         gfs2_glock_dq_uninit(&d_gh);
  98 fail:
  99         dput(parent);
 100         return 0;
 101 }
 102
 103 static 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
 109 static 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
 126 const struct dentry_operations gfs2_dops = {
 127         .d_revalidate = gfs2_drevalidate,
 128         .d_hash = gfs2_dhash,
 129         .d_delete = gfs2_dentry_delete,
 130 };
 131