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 version 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 #include <linux/lm_interface.h>
  19
  20 #include "gfs2.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 valid:
  87         dput(parent);
  88         return 1;
  89
  90 invalid_gunlock:
  91         gfs2_glock_dq_uninit(&d_gh);
  92 invalid:
  93         if (inode && S_ISDIR(inode->i_mode)) {
  94                 if (have_submounts(dentry))
  95                         goto valid;
  96                 shrink_dcache_parent(dentry);
  97         }
  98         d_drop(dentry);
  99         dput(parent);
 100         return 0;
 101
 102 fail_gunlock:
 103         gfs2_glock_dq_uninit(&d_gh);
 104 fail:
 105         dput(parent);
 106         return 0;
 107 }
 108
 109 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 110 {
 111         str->hash = gfs2_disk_hash(str->name, str->len);
 112         return 0;
 113 }
 114
 115 struct dentry_operations gfs2_dops = {
 116         .d_revalidate = gfs2_drevalidate,
 117         .d_hash = gfs2_dhash,
 118 };
 119