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/slab.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/completion.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/smp_lock.h>
  15 #include <linux/gfs2_ondisk.h>
  16 #include <linux/crc32.h>
  17 #include <linux/lm_interface.h>
  18
  19 #include "gfs2.h"
  20 #include "incore.h"
  21 #include "dir.h"
  22 #include "glock.h"
  23 #include "ops_dentry.h"
  24 #include "util.h"
  25
  26 /**
  27  * gfs2_drevalidate - Check directory lookup consistency
  28  * @dentry: the mapping to check
  29  * @nd:
  30  *
  31  * Check to make sure the lookup necessary to arrive at this inode from its
  32  * parent is still good.
  33  *
  34  * Returns: 1 if the dentry is ok, 0 if it isn't
  35  */
  36
  37 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  38 {
  39         struct dentry *parent = dget_parent(dentry);
  40         struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
  41         struct gfs2_inode *dip = GFS2_I(parent->d_inode);
  42         struct inode *inode = dentry->d_inode;
  43         struct gfs2_holder d_gh;
  44         struct gfs2_inode *ip;
  45         struct gfs2_inum_host inum;
  46         unsigned int type;
  47         int error;
  48         int had_lock=0;
  49
  50         if (inode && is_bad_inode(inode))
  51                 goto invalid;
  52
  53         if (sdp->sd_args.ar_localcaching)
  54                 goto valid;
  55
  56         had_lock = gfs2_glock_is_locked_by_me(dip->i_gl);
  57         if (!had_lock) {
  58                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  59                 if (error)
  60                         goto fail;
  61         }
  62
  63         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
  64         switch (error) {
  65         case 0:
  66                 if (!inode)
  67                         goto invalid_gunlock;
  68                 break;
  69         case -ENOENT:
  70                 if (!inode)
  71                         goto valid_gunlock;
  72                 goto invalid_gunlock;
  73         default:
  74                 goto fail_gunlock;
  75         }
  76
  77         ip = GFS2_I(inode);
  78
  79         if (!gfs2_inum_equal(&ip->i_num, &inum))
  80                 goto invalid_gunlock;
  81
  82         if (IF2DT(ip->i_inode.i_mode) != type) {
  83                 gfs2_consist_inode(dip);
  84                 goto fail_gunlock;
  85         }
  86
  87 valid_gunlock:
  88         if (!had_lock)
  89                 gfs2_glock_dq_uninit(&d_gh);
  90 valid:
  91         dput(parent);
  92         return 1;
  93
  94 invalid_gunlock:
  95         if (!had_lock)
  96                 gfs2_glock_dq_uninit(&d_gh);
  97 invalid:
  98         if (inode && S_ISDIR(inode->i_mode)) {
  99                 if (have_submounts(dentry))
 100                         goto valid;
 101                 shrink_dcache_parent(dentry);
 102         }
 103         d_drop(dentry);
 104         dput(parent);
 105         return 0;
 106
 107 fail_gunlock:
 108         gfs2_glock_dq_uninit(&d_gh);
 109 fail:
 110         dput(parent);
 111         return 0;
 112 }
 113
 114 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 115 {
 116         str->hash = gfs2_disk_hash(str->name, str->len);
 117         return 0;
 118 }
 119
 120 struct dentry_operations gfs2_dops = {
 121         .d_revalidate = gfs2_drevalidate,
 122         .d_hash = gfs2_dhash,
 123 };
 124