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 */
31static 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
48static 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(lock: &dentry->d_lock);
57 hlist_move_list(old: (struct hlist_head *)&dentry->d_fsdata, new: &head);
58 spin_unlock(lock: &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
64static 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(ptr: fid)) {
84 p9_debug(
85 P9_DEBUG_VFS,
86 "v9fs_fid_lookup: dentry = %pd (%p), got error %pe\n",
87 dentry, dentry, fid);
88 return PTR_ERR(ptr: fid);
89 }
90
91 v9ses = v9fs_inode2v9ses(inode);
92 if (v9fs_proto_dotl(v9ses))
93 retval = v9fs_refresh_inode_dotl(fid, inode);
94 else
95 retval = v9fs_refresh_inode(fid, inode);
96 p9_fid_put(fid);
97
98 if (retval == -ENOENT) {
99 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to ENOENT\n",
100 dentry, dentry);
101 return 0;
102 }
103 if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
104 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to type change\n",
105 dentry, dentry);
106 return 0;
107 }
108 if (retval < 0) {
109 p9_debug(P9_DEBUG_VFS,
110 "refresh inode: dentry = %pd (%p), got error %pe\n",
111 dentry, dentry, ERR_PTR(retval));
112 return retval;
113 }
114 }
115out_valid:
116 p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) is valid\n", dentry, dentry);
117 return 1;
118}
119
120static int v9fs_lookup_revalidate(struct inode *dir, const struct qstr *name,
121 struct dentry *dentry, unsigned int flags)
122{
123 return __v9fs_lookup_revalidate(dentry, flags);
124}
125
126static bool v9fs_dentry_unalias_trylock(const struct dentry *dentry)
127{
128 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
129 return down_write_trylock(sem: &v9ses->rename_sem);
130}
131
132static void v9fs_dentry_unalias_unlock(const struct dentry *dentry)
133{
134 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
135 up_write(sem: &v9ses->rename_sem);
136}
137
138const struct dentry_operations v9fs_cached_dentry_operations = {
139 .d_revalidate = v9fs_lookup_revalidate,
140 .d_weak_revalidate = __v9fs_lookup_revalidate,
141 .d_delete = v9fs_cached_dentry_delete,
142 .d_release = v9fs_dentry_release,
143 .d_unalias_trylock = v9fs_dentry_unalias_trylock,
144 .d_unalias_unlock = v9fs_dentry_unalias_unlock,
145};
146
147const struct dentry_operations v9fs_dentry_operations = {
148 .d_release = v9fs_dentry_release,
149 .d_unalias_trylock = v9fs_dentry_unalias_trylock,
150 .d_unalias_unlock = v9fs_dentry_unalias_unlock,
151};
152

source code of linux/fs/9p/vfs_dentry.c