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 #include "inode.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 = NULL;
  45         int error;
  46         int had_lock=0;
  47
  48         if (inode) {
  49                 if (is_bad_inode(inode))
  50                         goto invalid;
  51                 ip = GFS2_I(inode);
  52         }
  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_check(parent->d_inode, &dentry->d_name, ip);
  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 valid_gunlock:
  79         if (!had_lock)
  80                 gfs2_glock_dq_uninit(&d_gh);
  81 valid:
  82         dput(parent);
  83         return 1;
  84
  85 invalid_gunlock:
  86         if (!had_lock)
  87                 gfs2_glock_dq_uninit(&d_gh);
  88 invalid:
  89         if (inode && S_ISDIR(inode->i_mode)) {
  90                 if (have_submounts(dentry))
  91                         goto valid;
  92                 shrink_dcache_parent(dentry);
  93         }
  94         d_drop(dentry);
  95         dput(parent);
  96         return 0;
  97
  98 fail_gunlock:
  99         gfs2_glock_dq_uninit(&d_gh);
 100 fail:
 101         dput(parent);
 102         return 0;
 103 }
 104
 105 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 106 {
 107         str->hash = gfs2_disk_hash(str->name, str->len);
 108         return 0;
 109 }
 110
 111 struct dentry_operations gfs2_dops = {
 112         .d_revalidate = gfs2_drevalidate,
 113         .d_hash = gfs2_dhash,
 114 };
 115