drivers/staging/pohmelfs/path_entry.c

   1 /*
   2  * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
   3  * All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/ktime.h>
  20 #include <linux/fs_struct.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/writeback.h>
  23 #include <linux/mount.h>
  24 #include <linux/mm.h>
  25
  26 #include "netfs.h"
  27
  28 #define UNHASHED_OBSCURE_STRING_SIZE            sizeof(" (deleted)")
  29
  30 /*
  31  * Create path from root for given inode.
  32  * Path is formed as set of stuctures, containing name of the object
  33  * and its inode data (mode, permissions and so on).
  34  */
  35 int pohmelfs_construct_path_string(struct pohmelfs_inode *pi, void *data, int len)
  36 {
  37         struct path path;
  38         struct dentry *d;
  39         char *ptr;
  40         int err = 0, strlen, reduce = 0;
  41
  42         d = d_find_alias(&pi->vfs_inode);
  43         if (!d) {
  44                 printk("%s: no alias, list_empty: %d.\n", __func__, list_empty(&pi->vfs_inode.i_dentry));
  45                 return -ENOENT;
  46         }
  47
  48         read_lock(&current->fs->lock);
  49         path.mnt = mntget(current->fs->root.mnt);
  50         read_unlock(&current->fs->lock);
  51
  52         path.dentry = d;
  53
  54         if (!IS_ROOT(d) && d_unhashed(d))
  55                 reduce = 1;
  56
  57         ptr = d_path(&path, data, len);
  58         if (IS_ERR(ptr)) {
  59                 err = PTR_ERR(ptr);
  60                 goto out;
  61         }
  62
  63         if (reduce && len >= UNHASHED_OBSCURE_STRING_SIZE) {
  64                 char *end = data + len - UNHASHED_OBSCURE_STRING_SIZE;
  65                 *end = '\0';
  66         }
  67
  68         strlen = len - (ptr - (char *)data);
  69         memmove(data, ptr, strlen);
  70         ptr = data;
  71
  72         err = strlen;
  73
  74         dprintk("%s: dname: '%s', len: %u, maxlen: %u, name: '%s', strlen: %d.\n",
  75                         __func__, d->d_name.name, d->d_name.len, len, ptr, strlen);
  76
  77 out:
  78         dput(d);
  79         mntput(path.mnt);
  80
  81         return err;
  82 }
  83
  84 int pohmelfs_path_length(struct pohmelfs_inode *pi)
  85 {
  86         struct dentry *d, *root, *first;
  87         int len = 1; /* Root slash */
  88
  89         first = d = d_find_alias(&pi->vfs_inode);
  90         if (!d) {
  91                 dprintk("%s: ino: %llu, mode: %o.\n", __func__, pi->ino, pi->vfs_inode.i_mode);
  92                 return -ENOENT;
  93         }
  94
  95         read_lock(&current->fs->lock);
  96         root = dget(current->fs->root.dentry);
  97         read_unlock(&current->fs->lock);
  98
  99         spin_lock(&dcache_lock);
 100
 101         if (!IS_ROOT(d) && d_unhashed(d))
 102                 len += UNHASHED_OBSCURE_STRING_SIZE; /* Obscure " (deleted)" string */
 103
 104         while (d && d != root && !IS_ROOT(d)) {
 105                 len += d->d_name.len + 1; /* Plus slash */
 106                 d = d->d_parent;
 107         }
 108         spin_unlock(&dcache_lock);
 109
 110         dput(root);
 111         dput(first);
 112
 113         return len + 1; /* Including zero-byte */
 114 }