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/namei.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  * @flags: lookup flags
  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, unsigned int flags)
  37 {
  38         struct dentry *parent;
  39         struct gfs2_sbd *sdp;
  40         struct gfs2_inode *dip;
  41         struct inode *inode;
  42         struct gfs2_holder d_gh;
  43         struct gfs2_inode *ip = NULL;
  44         int error;
  45         int had_lock = 0;
  46
  47         if (flags & LOOKUP_RCU)
  48                 return -ECHILD;
  49
  50         parent = dget_parent(dentry);
  51         sdp = GFS2_SB(d_inode(parent));
  52         dip = GFS2_I(d_inode(parent));
  53         inode = d_inode(dentry);
  54
  55         if (inode) {
  56                 if (is_bad_inode(inode))
  57                         goto invalid;
  58                 ip = GFS2_I(inode);
  59         }
  60
  61         if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
  62                 goto valid;
  63
  64         had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
  65         if (!had_lock) {
  66                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
  67                 if (error)
  68                         goto fail;
  69         }
  70
  71         error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
  72         switch (error) {
  73         case 0:
  74                 if (!inode)
  75                         goto invalid_gunlock;
  76                 break;
  77         case -ENOENT:
  78                 if (!inode)
  79                         goto valid_gunlock;
  80                 goto invalid_gunlock;
  81         default:
  82                 goto fail_gunlock;
  83         }
  84
  85 valid_gunlock:
  86         if (!had_lock)
  87                 gfs2_glock_dq_uninit(&d_gh);
  88 valid:
  89         dput(parent);
  90         return 1;
  91
  92 invalid_gunlock:
  93         if (!had_lock)
  94                 gfs2_glock_dq_uninit(&d_gh);
  95 invalid:
  96         dput(parent);
  97         return 0;
  98
  99 fail_gunlock:
 100         gfs2_glock_dq_uninit(&d_gh);
 101 fail:
 102         dput(parent);
 103         return 0;
 104 }
 105
 106 static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
 107 {
 108         str->hash = gfs2_disk_hash(str->name, str->len);
 109         return 0;
 110 }
 111
 112 static int gfs2_dentry_delete(const struct dentry *dentry)
 113 {
 114         struct gfs2_inode *ginode;
 115
 116         if (d_really_is_negative(dentry))
 117                 return 0;
 118
 119         ginode = GFS2_I(d_inode(dentry));
 120         if (!ginode->i_iopen_gh.gh_gl)
 121                 return 0;
 122
 123         if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
 124                 return 1;
 125
 126         return 0;
 127 }
 128
 129 const struct dentry_operations gfs2_dops = {
 130         .d_revalidate = gfs2_drevalidate,
 131         .d_hash = gfs2_dhash,
 132         .d_delete = gfs2_dentry_delete,
 133 };
 134