release/src-rt-6.x.4708/linux/linux-2.6.36/fs/gfs2/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/spinlock.h>
  11 #include <linux/completion.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/gfs2_ondisk.h>
  14 #include <linux/crc32.h>
  15
  16 #include "gfs2.h"
  17 #include "incore.h"
  18 #include "dir.h"
  19 #include "glock.h"
  20 #include "super.h"
  21 #include "util.h"
  22 #include "inode.h"
  23
  24 /**
  25  * gfs2_drevalidate - Check directory lookup consistency
  26  * @dentry: the mapping to check
  27  * @nd:
  28  *
  29  * Check to make sure the lookup necessary to arrive at this inode from its
  30  * parent is still good.
  31  *
  32  * Returns: 1 if the dentry is ok, 0 if it isn't
  33  */
  34
  35 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  36 {
  37         struct dentry *parent = dget_parent(dentry);
  38         struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
  39         struct gfs2_inode *dip = GFS2_I(parent->d_inode);
  40         struct inode *inode = dentry->d_inode;
  41         struct gfs2_holder d_gh;
  42         struct gfs2_inode *ip = NULL;
  43         int error;
  44         int had_lock = 0;
  45
  46         if (inode) {
  47                 if (is_bad_inode(inode))
  48                         goto invalid;
  49                 ip = GFS2_I(inode);
  50         }
  51
  52         if (sdp->sd_args.ar_localcaching)
  53                 goto valid;
  54
  55         had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  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_check(parent->d_inode, &dentry->d_name, ip);
  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 valid_gunlock:
  77         if (!had_lock)
  78                 gfs2_glock_dq_uninit(&d_gh);
  79 valid:
  80         dput(parent);
  81         return 1;
  82
  83 invalid_gunlock:
  84         if (!had_lock)
  85                 gfs2_glock_dq_uninit(&d_gh);
  86 invalid:
  87         if (inode && S_ISDIR(inode->i_mode)) {
  88                 if (have_submounts(dentry))
  89                         goto valid;
  90                 shrink_dcache_parent(dentry);
  91         }
  92         d_drop(dentry);
  93         dput(parent);
  94         return 0;
  95
  96 fail_gunlock:
  97         gfs2_glock_dq_uninit(&d_gh);
  98 fail:
  99         dput(parent);
 100         return 0;
 101 }
 102
 103 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 104 {
 105         str->hash = gfs2_disk_hash(str->name, str->len);
 106         return 0;
 107 }
 108
 109 static int gfs2_dentry_delete(struct dentry *dentry)
 110 {
 111         struct gfs2_inode *ginode;
 112
 113         if (!dentry->d_inode)
 114                 return 0;
 115
 116         ginode = GFS2_I(dentry->d_inode);
 117         if (!ginode->i_iopen_gh.gh_gl)
 118                 return 0;
 119
 120         if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 121                 return 1;
 122
 123         return 0;
 124 }
 125
 126 const struct dentry_operations gfs2_dops = {
 127         .d_revalidate = gfs2_drevalidate,
 128         .d_hash = gfs2_dhash,
 129         .d_delete = gfs2_dentry_delete,
 130 };