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/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
  17 #include "gfs2.h"
  18 #include "incore.h"
  19 #include "dir.h"
  20 #include "glock.h"
  21 #include "super.h"
  22 #include "util.h"
  23 #include "inode.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 = NULL;
  44         int error;
  45         int had_lock = 0;
  46
  47         if (inode) {
  48                 if (is_bad_inode(inode))
  49                         goto invalid;
  50                 ip = GFS2_I(inode);
  51         }
  52
  53         if (sdp->sd_args.ar_localcaching)
  54                 goto valid;
  55
  56         had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  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_check(parent->d_inode, &dentry->d_name, ip);
  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 valid_gunlock:
  78         if (!had_lock)
  79                 gfs2_glock_dq_uninit(&d_gh);
  80 valid:
  81         dput(parent);
  82         return 1;
  83
  84 invalid_gunlock:
  85         if (!had_lock)
  86                 gfs2_glock_dq_uninit(&d_gh);
  87 invalid:
  88         if (inode && S_ISDIR(inode->i_mode)) {
  89                 if (have_submounts(dentry))
  90                         goto valid;
  91                 shrink_dcache_parent(dentry);
  92         }
  93         d_drop(dentry);
  94         dput(parent);
  95         return 0;
  96
  97 fail_gunlock:
  98         gfs2_glock_dq_uninit(&d_gh);
  99 fail:
 100         dput(parent);
 101         return 0;
 102 }
 103
 104 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 105 {
 106         str->hash = gfs2_disk_hash(str->name, str->len);
 107         return 0;
 108 }
 109
 110 static int gfs2_dentry_delete(struct dentry *dentry)
 111 {
 112         struct gfs2_inode *ginode;
 113
 114         if (!dentry->d_inode)
 115                 return 0;
 116
 117         ginode = GFS2_I(dentry->d_inode);
 118         if (!ginode->i_iopen_gh.gh_gl)
 119                 return 0;
 120
 121         if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 122                 return 1;
 123
 124         return 0;
 125 }
 126
 127 const struct dentry_operations gfs2_dops = {
 128         .d_revalidate = gfs2_drevalidate,
 129         .d_hash = gfs2_dhash,
 130         .d_delete = gfs2_dentry_delete,
 131 };
 132