fs/gfs2/ops_dentry.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 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 <asm/semaphore.h>
  17
  18 #include "gfs2.h"
  19 #include "dir.h"
  20 #include "glock.h"
  21 #include "ops_dentry.h"
  22
  23 /**
  24  * gfs2_drevalidate - Check directory lookup consistency
  25  * @dentry: the mapping to check
  26  * @nd:
  27  *
  28  * Check to make sure the lookup necessary to arrive at this inode from its
  29  * parent is still good.
  30  *
  31  * Returns: 1 if the dentry is ok, 0 if it isn't
  32  */
  33
  34 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  35 {
  36         struct dentry *parent = dget_parent(dentry);
  37         struct gfs2_inode *dip = get_v2ip(parent->d_inode);
  38         struct inode *inode;
  39         struct gfs2_holder d_gh;
  40         struct gfs2_inode *ip;
  41         struct gfs2_inum inum;
  42         unsigned int type;
  43         int error;
  44
  45         lock_kernel();
  46
  47         inode = dentry->d_inode;
  48         if (inode && is_bad_inode(inode))
  49                 goto invalid;
  50
  51         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  52         if (error)
  53                 goto fail;
  54
  55         error = gfs2_dir_search(dip, &dentry->d_name, &inum, &type);
  56         switch (error) {
  57         case 0:
  58                 if (!inode)
  59                         goto invalid_gunlock;
  60                 break;
  61         case -ENOENT:
  62                 if (!inode)
  63                         goto valid_gunlock;
  64                 goto invalid_gunlock;
  65         default:
  66                 goto fail_gunlock;
  67         }
  68
  69         ip = get_v2ip(inode);
  70
  71         if (!gfs2_inum_equal(&ip->i_num, &inum))
  72                 goto invalid_gunlock;
  73
  74         if (IF2DT(ip->i_di.di_mode) != type) {
  75                 gfs2_consist_inode(dip);
  76                 goto fail_gunlock;
  77         }
  78
  79  valid_gunlock:
  80         gfs2_glock_dq_uninit(&d_gh);
  81
  82  valid:
  83         unlock_kernel();
  84         dput(parent);
  85         return 1;
  86
  87  invalid_gunlock:
  88         gfs2_glock_dq_uninit(&d_gh);
  89
  90  invalid:
  91         if (inode && S_ISDIR(inode->i_mode)) {
  92                 if (have_submounts(dentry))
  93                         goto valid;
  94                 shrink_dcache_parent(dentry);
  95         }
  96         d_drop(dentry);
  97
  98         unlock_kernel();
  99         dput(parent);
 100         return 0;
 101
 102  fail_gunlock:
 103         gfs2_glock_dq_uninit(&d_gh);
 104
 105  fail:
 106         unlock_kernel();
 107         dput(parent);
 108         return 0;
 109 }
 110
 111 struct dentry_operations gfs2_dops = {
 112         .d_revalidate = gfs2_drevalidate,
 113 };
 114