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 gfs2_sbd *sdp = dip->i_sbd;
  39         struct inode *inode;
  40         struct gfs2_holder d_gh;
  41         struct gfs2_inode *ip;
  42         struct gfs2_inum inum;
  43         unsigned int type;
  44         int error;
  45
  46         lock_kernel();
  47
  48         atomic_inc(&sdp->sd_ops_dentry);
  49
  50         inode = dentry->d_inode;
  51         if (inode && is_bad_inode(inode))
  52                 goto invalid;
  53
  54         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  55         if (error)
  56                 goto fail;
  57
  58         error = gfs2_dir_search(dip, &dentry->d_name, &inum, &type);
  59         switch (error) {
  60         case 0:
  61                 if (!inode)
  62                         goto invalid_gunlock;
  63                 break;
  64         case -ENOENT:
  65                 if (!inode)
  66                         goto valid_gunlock;
  67                 goto invalid_gunlock;
  68         default:
  69                 goto fail_gunlock;
  70         }
  71
  72         ip = get_v2ip(inode);
  73
  74         if (!gfs2_inum_equal(&ip->i_num, &inum))
  75                 goto invalid_gunlock;
  76
  77         if (IF2DT(ip->i_di.di_mode) != type) {
  78                 gfs2_consist_inode(dip);
  79                 goto fail_gunlock;
  80         }
  81
  82  valid_gunlock:
  83         gfs2_glock_dq_uninit(&d_gh);
  84
  85  valid:
  86         unlock_kernel();
  87         dput(parent);
  88         return 1;
  89
  90  invalid_gunlock:
  91         gfs2_glock_dq_uninit(&d_gh);
  92
  93  invalid:
  94         if (inode && S_ISDIR(inode->i_mode)) {
  95                 if (have_submounts(dentry))
  96                         goto valid;
  97                 shrink_dcache_parent(dentry);
  98         }
  99         d_drop(dentry);
 100
 101         unlock_kernel();
 102         dput(parent);
 103         return 0;
 104
 105  fail_gunlock:
 106         gfs2_glock_dq_uninit(&d_gh);
 107
 108  fail:
 109         unlock_kernel();
 110         dput(parent);
 111         return 0;
 112 }
 113
 114 struct dentry_operations gfs2_dops = {
 115         .d_revalidate = gfs2_drevalidate,
 116 };
 117