fs/gfs2/ops_dentry.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 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 v.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 <asm/semaphore.h>
  19
  20 #include "gfs2.h"
  21 #include "lm_interface.h"
  22 #include "incore.h"
  23 #include "dir.h"
  24 #include "glock.h"
  25 #include "ops_dentry.h"
  26 #include "util.h"
  27
  28 /**
  29  * gfs2_drevalidate - Check directory lookup consistency
  30  * @dentry: the mapping to check
  31  * @nd:
  32  *
  33  * Check to make sure the lookup necessary to arrive at this inode from its
  34  * parent is still good.
  35  *
  36  * Returns: 1 if the dentry is ok, 0 if it isn't
  37  */
  38
  39 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
  40 {
  41         struct dentry *parent = dget_parent(dentry);
  42         struct gfs2_sbd *sdp = parent->d_inode->i_sb->s_fs_info;
  43         struct gfs2_inode *dip = parent->d_inode->u.generic_ip;
  44         struct inode *inode = dentry->d_inode;
  45         struct gfs2_holder d_gh;
  46         struct gfs2_inode *ip;
  47         struct gfs2_inum inum;
  48         unsigned int type;
  49         int error;
  50
  51         if (inode && is_bad_inode(inode))
  52                 goto invalid;
  53
  54         if (sdp->sd_args.ar_localcaching)
  55                 goto valid;
  56
  57         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  58         if (error)
  59                 goto fail;
  60
  61         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
  62         switch (error) {
  63         case 0:
  64                 if (!inode)
  65                         goto invalid_gunlock;
  66                 break;
  67         case -ENOENT:
  68                 if (!inode)
  69                         goto valid_gunlock;
  70                 goto invalid_gunlock;
  71         default:
  72                 goto fail_gunlock;
  73         }
  74
  75         ip = inode->u.generic_ip;
  76
  77         if (!gfs2_inum_equal(&ip->i_num, &inum))
  78                 goto invalid_gunlock;
  79
  80         if (IF2DT(ip->i_di.di_mode) != type) {
  81                 gfs2_consist_inode(dip);
  82                 goto fail_gunlock;
  83         }
  84
  85  valid_gunlock:
  86         gfs2_glock_dq_uninit(&d_gh);
  87
  88  valid:
  89         dput(parent);
  90         return 1;
  91
  92  invalid_gunlock:
  93         gfs2_glock_dq_uninit(&d_gh);
  94
  95  invalid:
  96         if (inode && S_ISDIR(inode->i_mode)) {
  97                 if (have_submounts(dentry))
  98                         goto valid;
  99                 shrink_dcache_parent(dentry);
 100         }
 101         d_drop(dentry);
 102
 103         dput(parent);
 104         return 0;
 105
 106  fail_gunlock:
 107         gfs2_glock_dq_uninit(&d_gh);
 108
 109  fail:
 110         dput(parent);
 111         return 0;
 112 }
 113
 114 static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
 115 {
 116         str->hash = gfs2_disk_hash(str->name, str->len);
 117         return 0;
 118 }
 119
 120 struct dentry_operations gfs2_dops = {
 121         .d_revalidate = gfs2_drevalidate,
 122         .d_hash = gfs2_dhash,
 123 };
 124