fs/gfs2/ops_dentry.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/gfs2_ondisk.h>
  17 #include <linux/crc32.h>
  18
  19 #include "gfs2.h"
  20 #include "lm_interface.h"
  21 #include "incore.h"
  22 #include "dir.h"
  23 #include "glock.h"
  24 #include "ops_dentry.h"
  25 #include "util.h"
  26
  27 /**
  28  * gfs2_drevalidate - Check directory lookup consistency
  29  * @dentry: the mapping to check
  30  * @nd:
  31  *
  32  * Check to make sure the lookup necessary to arrive at this inode from its
  33  * parent is still good.
  34  *
  35  * Returns: 1 if the dentry is ok, 0 if it isn't
  36  */
  37
  38 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  39 {
  40         struct dentry *parent = dget_parent(dentry);
  41         struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
  42         struct gfs2_inode *dip = GFS2_I(parent->d_inode);
  43         struct inode *inode = dentry->d_inode;
  44         struct gfs2_holder d_gh;
  45         struct gfs2_inode *ip;
  46         struct gfs2_inum inum;
  47         unsigned int type;
  48         int error;
  49
  50         if (inode && is_bad_inode(inode))
  51                 goto invalid;
  52
  53         if (sdp->sd_args.ar_localcaching)
  54                 goto valid;
  55
  56         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  57         if (error)
  58                 goto fail;
  59
  60         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
  61         switch (error) {
  62         case 0:
  63                 if (!inode)
  64                         goto invalid_gunlock;
  65                 break;
  66         case -ENOENT:
  67                 if (!inode)
  68                         goto valid_gunlock;
  69                 goto invalid_gunlock;
  70         default:
  71                 goto fail_gunlock;
  72         }
  73
  74         ip = GFS2_I(inode);
  75
  76         if (!gfs2_inum_equal(&ip->i_num, &inum))
  77                 goto invalid_gunlock;
  78
  79         if (IF2DT(ip->i_di.di_mode) != type) {
  80                 gfs2_consist_inode(dip);
  81                 goto fail_gunlock;
  82         }
  83
  84  valid_gunlock:
  85         gfs2_glock_dq_uninit(&d_gh);
  86
  87  valid:
  88         dput(parent);
  89         return 1;
  90
  91  invalid_gunlock:
  92         gfs2_glock_dq_uninit(&d_gh);
  93
  94  invalid:
  95         if (inode && S_ISDIR(inode->i_mode)) {
  96                 if (have_submounts(dentry))
  97                         goto valid;
  98                 shrink_dcache_parent(dentry);
  99         }
 100         d_drop(dentry);
 101
 102         dput(parent);
 103         return 0;
 104
 105  fail_gunlock:
 106         gfs2_glock_dq_uninit(&d_gh);
 107
 108  fail:
 109         dput(parent);
 110         return 0;
 111 }
 112
 113 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 114 {
 115         str->hash = gfs2_disk_hash(str->name, str->len);
 116         return 0;
 117 }
 118
 119 struct dentry_operations gfs2_dops = {
 120         .d_revalidate = gfs2_drevalidate,
 121         .d_hash = gfs2_dhash,
 122 };
 123