git.oblomov.eu Git - linux-2.6/blob - 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_host inum;
  47         unsigned int type;
  48         int error;
  49         int had_lock=0;
  50
  51         if (inode && is_bad_inode(inode))
  52                 goto invalid;
  53
  54         if (sdp->sd_args.ar_localcaching)
  55                 goto valid;
  56
  57         had_lock = gfs2_glock_is_locked_by_me(dip->i_gl);
  58         if (!had_lock) {
  59                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  60                 if (error)
  61                         goto fail;
  62         }
  63
  64         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
  65         switch (error) {
  66         case 0:
  67                 if (!inode)
  68                         goto invalid_gunlock;
  69                 break;
  70         case -ENOENT:
  71                 if (!inode)
  72                         goto valid_gunlock;
  73                 goto invalid_gunlock;
  74         default:
  75                 goto fail_gunlock;
  76         }
  77
  78         ip = GFS2_I(inode);
  79
  80         if (!gfs2_inum_equal(&ip->i_num, &inum))
  81                 goto invalid_gunlock;
  82
  83         if (IF2DT(ip->i_inode.i_mode) != type) {
  84                 gfs2_consist_inode(dip);
  85                 goto fail_gunlock;
  86         }
  87
  88 valid_gunlock:
  89         if (!had_lock)
  90                 gfs2_glock_dq_uninit(&d_gh);
  91 valid:
  92         dput(parent);
  93         return 1;
  94
  95 invalid_gunlock:
  96         if (!had_lock)
  97                 gfs2_glock_dq_uninit(&d_gh);
  98 invalid:
  99         if (inode && S_ISDIR(inode->i_mode)) {
 100                 if (have_submounts(dentry))
 101                         goto valid;
 102                 shrink_dcache_parent(dentry);
 103         }
 104         d_drop(dentry);
 105         dput(parent);
 106         return 0;
 107
 108 fail_gunlock:
 109         gfs2_glock_dq_uninit(&d_gh);
 110 fail:
 111         dput(parent);
 112         return 0;
 113 }
 114
 115 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 116 {
 117         str->hash = gfs2_disk_hash(str->name, str->len);
 118         return 0;
 119 }
 120
 121 struct dentry_operations gfs2_dops = {
 122         .d_revalidate = gfs2_drevalidate,
 123         .d_hash = gfs2_dhash,
 124 };
 125