fs/9p/vfs_dentry.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/9p/vfs_dentry.c
   4  *
   5  * This file contians vfs dentry ops for the 9P2000 protocol.
   6  *
   7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/file.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/stat.h>
  17 #include <linux/string.h>
  18 #include <linux/inet.h>
  19 #include <linux/namei.h>
  20 #include <linux/idr.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <net/9p/9p.h>
  24 #include <net/9p/client.h>
  25
  26 #include "v9fs.h"
  27 #include "v9fs_vfs.h"
  28 #include "fid.h"
  29
  30 /**
  31  * v9fs_cached_dentry_delete - called when dentry refcount equals 0
  32  * @dentry:  dentry in question
  33  *
  34  */
  35 static int v9fs_cached_dentry_delete(const struct dentry *dentry)
  36 {
  37         p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  38                  dentry, dentry);
  39
  40         /* Don't cache negative dentries */
  41         if (d_really_is_negative(dentry))
  42                 return 1;
  43         return 0;
  44 }
  45
  46 /**
  47  * v9fs_dentry_release - called when dentry is going to be freed
  48  * @dentry:  dentry that is being release
  49  *
  50  */
  51
  52 static void v9fs_dentry_release(struct dentry *dentry)
  53 {
  54         struct hlist_node *p, *n;
  55         p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  56                  dentry, dentry);
  57         hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
  58                 p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
  59         dentry->d_fsdata = NULL;
  60 }
  61
  62 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
  63 {
  64         struct p9_fid *fid;
  65         struct inode *inode;
  66         struct v9fs_inode *v9inode;
  67
  68         if (flags & LOOKUP_RCU)
  69                 return -ECHILD;
  70
  71         inode = d_inode(dentry);
  72         if (!inode)
  73                 goto out_valid;
  74
  75         v9inode = V9FS_I(inode);
  76         if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
  77                 int retval;
  78                 struct v9fs_session_info *v9ses;
  79                 fid = v9fs_fid_lookup(dentry);
  80                 if (IS_ERR(fid))
  81                         return PTR_ERR(fid);
  82
  83                 v9ses = v9fs_inode2v9ses(inode);
  84                 if (v9fs_proto_dotl(v9ses))
  85                         retval = v9fs_refresh_inode_dotl(fid, inode);
  86                 else
  87                         retval = v9fs_refresh_inode(fid, inode);
  88                 p9_client_clunk(fid);
  89
  90                 if (retval == -ENOENT)
  91                         return 0;
  92                 if (retval < 0)
  93                         return retval;
  94         }
  95 out_valid:
  96         return 1;
  97 }
  98
  99 const struct dentry_operations v9fs_cached_dentry_operations = {
 100         .d_revalidate = v9fs_lookup_revalidate,
 101         .d_weak_revalidate = v9fs_lookup_revalidate,
 102         .d_delete = v9fs_cached_dentry_delete,
 103         .d_release = v9fs_dentry_release,
 104 };
 105
 106 const struct dentry_operations v9fs_dentry_operations = {
 107         .d_delete = always_delete_dentry,
 108         .d_release = v9fs_dentry_release,
 109 };