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 */
v9fs_cached_dentry_delete(const struct dentry * dentry)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
v9fs_dentry_release(struct dentry * dentry)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
__v9fs_lookup_revalidate(struct dentry * dentry,unsigned int flags)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
v9fs_lookup_revalidate(struct inode * dir,const struct qstr * name,struct dentry * dentry,unsigned int flags)102 static int v9fs_lookup_revalidate(struct inode *dir, const struct qstr *name,
103 struct dentry *dentry, unsigned int flags)
104 {
105 return __v9fs_lookup_revalidate(dentry, flags);
106 }
107
v9fs_dentry_unalias_trylock(const struct dentry * dentry)108 static bool v9fs_dentry_unalias_trylock(const struct dentry *dentry)
109 {
110 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
111 return down_write_trylock(&v9ses->rename_sem);
112 }
113
v9fs_dentry_unalias_unlock(const struct dentry * dentry)114 static void v9fs_dentry_unalias_unlock(const struct dentry *dentry)
115 {
116 struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
117 up_write(&v9ses->rename_sem);
118 }
119
120 const struct dentry_operations v9fs_cached_dentry_operations = {
121 .d_revalidate = v9fs_lookup_revalidate,
122 .d_weak_revalidate = __v9fs_lookup_revalidate,
123 .d_delete = v9fs_cached_dentry_delete,
124 .d_release = v9fs_dentry_release,
125 .d_unalias_trylock = v9fs_dentry_unalias_trylock,
126 .d_unalias_unlock = v9fs_dentry_unalias_unlock,
127 };
128
129 const struct dentry_operations v9fs_dentry_operations = {
130 .d_delete = always_delete_dentry,
131 .d_release = v9fs_dentry_release,
132 .d_unalias_trylock = v9fs_dentry_unalias_trylock,
133 .d_unalias_unlock = v9fs_dentry_unalias_unlock,
134 };
135