fs/9p/vfs_dentry.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This file contians vfs dentry ops for the 9P2000 protocol.
   4  *
   5  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   6  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/file.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/stat.h>
  15 #include <linux/string.h>
  16 #include <linux/namei.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <net/9p/9p.h>
  20 #include <net/9p/client.h>
  21
  22 #include "v9fs.h"
  23 #include "v9fs_vfs.h"
  24 #include "fid.h"
  25
  26 /**
  27  * v9fs_cached_dentry_delete - called when dentry refcount equals 0
  28  * @dentry:  dentry in question
  29  *
  30  */
  31 static int v9fs_cached_dentry_delete(const struct dentry *dentry)
  32 {
  33         p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  34                  dentry, dentry);
  35
  36         /* Don't cache negative dentries */
  37         if (d_really_is_negative(dentry))
  38                 return 1;
  39         return 0;
  40 }
  41
  42 /**
  43  * v9fs_dentry_release - called when dentry is going to be freed
  44  * @dentry:  dentry that is being release
  45  *
  46  */
  47
  48 static void v9fs_dentry_release(struct dentry *dentry)
  49 {
  50         struct hlist_node *p, *n;
  51         struct hlist_head head;
  52
  53         p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
  54                  dentry, dentry);
  55
  56         spin_lock(&dentry->d_lock);
  57         hlist_move_list((struct hlist_head *)&dentry->d_fsdata, &head);
  58         spin_unlock(&dentry->d_lock);
  59
  60         hlist_for_each_safe(p, n, &head)
  61                 p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
  62 }
  63
  64 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
  65 {
  66         struct p9_fid *fid;
  67         struct inode *inode;
  68         struct v9fs_inode *v9inode;
  69
  70         if (flags & LOOKUP_RCU)
  71                 return -ECHILD;
  72
  73         inode = d_inode(dentry);
  74         if (!inode)
  75                 goto out_valid;
  76
  77         v9inode = V9FS_I(inode);
  78         if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
  79                 int retval;
  80                 struct v9fs_session_info *v9ses;
  81
  82                 fid = v9fs_fid_lookup(dentry);
  83                 if (IS_ERR(fid))
  84                         return PTR_ERR(fid);
  85
  86                 v9ses = v9fs_inode2v9ses(inode);
  87                 if (v9fs_proto_dotl(v9ses))
  88                         retval = v9fs_refresh_inode_dotl(fid, inode);
  89                 else
  90                         retval = v9fs_refresh_inode(fid, inode);
  91                 p9_fid_put(fid);
  92
  93                 if (retval == -ENOENT)
  94                         return 0;
  95                 if (retval < 0)
  96                         return retval;
  97         }
  98 out_valid:
  99         return 1;
 100 }
 101
 102 const struct dentry_operations v9fs_cached_dentry_operations = {
 103         .d_revalidate = v9fs_lookup_revalidate,
 104         .d_weak_revalidate = v9fs_lookup_revalidate,
 105         .d_delete = v9fs_cached_dentry_delete,
 106         .d_release = v9fs_dentry_release,
 107 };
 108
 109 const struct dentry_operations v9fs_dentry_operations = {
 110         .d_delete = always_delete_dentry,
 111         .d_release = v9fs_dentry_release,
 112 };