fs/9p/vfs_dentry.c

   1 /*
   2  *  linux/fs/9p/vfs_dentry.c
   3  *
   4  * This file contians vfs dentry ops for the 9P2000 protocol.
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/file.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/namei.h>
  35 #include <linux/idr.h>
  36 #include <linux/sched.h>
  37 #include <linux/slab.h>
  38 #include <net/9p/9p.h>
  39 #include <net/9p/client.h>
  40
  41 #include "v9fs.h"
  42 #include "v9fs_vfs.h"
  43 #include "fid.h"
  44
  45 /**
  46  * v9fs_dentry_delete - called when dentry refcount equals 0
  47  * @dentry:  dentry in question
  48  *
  49  * By returning 1 here we should remove cacheing of unused
  50  * dentry components.
  51  *
  52  */
  53
  54 static int v9fs_dentry_delete(const struct dentry *dentry)
  55 {
  56         p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  57                  dentry->d_name.name, dentry);
  58
  59         return 1;
  60 }
  61
  62 /**
  63  * v9fs_cached_dentry_delete - called when dentry refcount equals 0
  64  * @dentry:  dentry in question
  65  *
  66  */
  67 static int v9fs_cached_dentry_delete(const struct dentry *dentry)
  68 {
  69         p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  70                  dentry->d_name.name, dentry);
  71
  72         /* Don't cache negative dentries */
  73         if (!dentry->d_inode)
  74                 return 1;
  75         return 0;
  76 }
  77
  78 /**
  79  * v9fs_dentry_release - called when dentry is going to be freed
  80  * @dentry:  dentry that is being release
  81  *
  82  */
  83
  84 static void v9fs_dentry_release(struct dentry *dentry)
  85 {
  86         struct hlist_node *p, *n;
  87         p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
  88                  dentry->d_name.name, dentry);
  89         hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
  90                 p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
  91         dentry->d_fsdata = NULL;
  92 }
  93
  94 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
  95 {
  96         struct p9_fid *fid;
  97         struct inode *inode;
  98         struct v9fs_inode *v9inode;
  99
 100         if (flags & LOOKUP_RCU)
 101                 return -ECHILD;
 102
 103         inode = dentry->d_inode;
 104         if (!inode)
 105                 goto out_valid;
 106
 107         v9inode = V9FS_I(inode);
 108         if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
 109                 int retval;
 110                 struct v9fs_session_info *v9ses;
 111                 fid = v9fs_fid_lookup(dentry);
 112                 if (IS_ERR(fid))
 113                         return PTR_ERR(fid);
 114
 115                 v9ses = v9fs_inode2v9ses(inode);
 116                 if (v9fs_proto_dotl(v9ses))
 117                         retval = v9fs_refresh_inode_dotl(fid, inode);
 118                 else
 119                         retval = v9fs_refresh_inode(fid, inode);
 120                 if (retval == -ENOENT)
 121                         return 0;
 122                 if (retval < 0)
 123                         return retval;
 124         }
 125 out_valid:
 126         return 1;
 127 }
 128
 129 const struct dentry_operations v9fs_cached_dentry_operations = {
 130         .d_revalidate = v9fs_lookup_revalidate,
 131         .d_weak_revalidate = v9fs_lookup_revalidate,
 132         .d_delete = v9fs_cached_dentry_delete,
 133         .d_release = v9fs_dentry_release,
 134 };
 135
 136 const struct dentry_operations v9fs_dentry_operations = {
 137         .d_delete = v9fs_dentry_delete,
 138         .d_release = v9fs_dentry_release,
 139 };