release/src-rt-6.x/linux/linux-2.6/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/gfs2_ondisk.h>
  15 #include <linux/crc32.h>
  16 #include <linux/lm_interface.h>
  17
  18 #include "gfs2.h"
  19 #include "incore.h"
  20 #include "dir.h"
  21 #include "glock.h"
  22 #include "ops_dentry.h"
  23 #include "util.h"
  24
  25 /**
  26  * gfs2_drevalidate - Check directory lookup consistency
  27  * @dentry: the mapping to check
  28  * @nd:
  29  *
  30  * Check to make sure the lookup necessary to arrive at this inode from its
  31  * parent is still good.
  32  *
  33  * Returns: 1 if the dentry is ok, 0 if it isn't
  34  */
  35
  36 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  37 {
  38         struct dentry *parent = dget_parent(dentry);
  39         struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
  40         struct gfs2_inode *dip = GFS2_I(parent->d_inode);
  41         struct inode *inode = dentry->d_inode;
  42         struct gfs2_holder d_gh;
  43         struct gfs2_inode *ip;
  44         struct gfs2_inum_host inum;
  45         unsigned int type;
  46         int error;
  47         int had_lock=0;
  48
  49         if (inode && is_bad_inode(inode))
  50                 goto invalid;
  51
  52         if (sdp->sd_args.ar_localcaching)
  53                 goto valid;
  54
  55         had_lock = gfs2_glock_is_locked_by_me(dip->i_gl);
  56         if (!had_lock) {
  57                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  58                 if (error)
  59                         goto fail;
  60         }
  61
  62         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
  63         switch (error) {
  64         case 0:
  65                 if (!inode)
  66                         goto invalid_gunlock;
  67                 break;
  68         case -ENOENT:
  69                 if (!inode)
  70                         goto valid_gunlock;
  71                 goto invalid_gunlock;
  72         default:
  73                 goto fail_gunlock;
  74         }
  75
  76         ip = GFS2_I(inode);
  77
  78         if (!gfs2_inum_equal(&ip->i_num, &inum))
  79                 goto invalid_gunlock;
  80
  81         if (IF2DT(ip->i_inode.i_mode) != type) {
  82                 gfs2_consist_inode(dip);
  83                 goto fail_gunlock;
  84         }
  85
  86 valid_gunlock:
  87         if (!had_lock)
  88                 gfs2_glock_dq_uninit(&d_gh);
  89 valid:
  90         dput(parent);
  91         return 1;
  92
  93 invalid_gunlock:
  94         if (!had_lock)
  95                 gfs2_glock_dq_uninit(&d_gh);
  96 invalid:
  97         if (inode && S_ISDIR(inode->i_mode)) {
  98                 if (have_submounts(dentry))
  99                         goto valid;
 100                 shrink_dcache_parent(dentry);
 101         }
 102         d_drop(dentry);
 103         dput(parent);
 104         return 0;
 105
 106 fail_gunlock:
 107         gfs2_glock_dq_uninit(&d_gh);
 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