xref: /openbmc/linux/fs/9p/vfs_dentry.c (revision 195c5ad9)
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/inet.h>
17 #include <linux/namei.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <net/9p/9p.h>
21 #include <net/9p/client.h>
22 
23 #include "v9fs.h"
24 #include "v9fs_vfs.h"
25 #include "fid.h"
26 
27 /**
28  * v9fs_cached_dentry_delete - called when dentry refcount equals 0
29  * @dentry:  dentry in question
30  *
31  */
32 static int v9fs_cached_dentry_delete(const struct dentry *dentry)
33 {
34 	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
35 		 dentry, dentry);
36 
37 	/* Don't cache negative dentries */
38 	if (d_really_is_negative(dentry))
39 		return 1;
40 	return 0;
41 }
42 
43 /**
44  * v9fs_dentry_release - called when dentry is going to be freed
45  * @dentry:  dentry that is being release
46  *
47  */
48 
49 static void v9fs_dentry_release(struct dentry *dentry)
50 {
51 	struct hlist_node *p, *n;
52 
53 	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
54 		 dentry, dentry);
55 	hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
56 		p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
57 	dentry->d_fsdata = NULL;
58 }
59 
60 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
61 {
62 	struct p9_fid *fid;
63 	struct inode *inode;
64 	struct v9fs_inode *v9inode;
65 
66 	if (flags & LOOKUP_RCU)
67 		return -ECHILD;
68 
69 	inode = d_inode(dentry);
70 	if (!inode)
71 		goto out_valid;
72 
73 	v9inode = V9FS_I(inode);
74 	if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
75 		int retval;
76 		struct v9fs_session_info *v9ses;
77 
78 		fid = v9fs_fid_lookup(dentry);
79 		if (IS_ERR(fid))
80 			return PTR_ERR(fid);
81 
82 		v9ses = v9fs_inode2v9ses(inode);
83 		if (v9fs_proto_dotl(v9ses))
84 			retval = v9fs_refresh_inode_dotl(fid, inode);
85 		else
86 			retval = v9fs_refresh_inode(fid, inode);
87 		p9_fid_put(fid);
88 
89 		if (retval == -ENOENT)
90 			return 0;
91 		if (retval < 0)
92 			return retval;
93 	}
94 out_valid:
95 	return 1;
96 }
97 
98 const struct dentry_operations v9fs_cached_dentry_operations = {
99 	.d_revalidate = v9fs_lookup_revalidate,
100 	.d_weak_revalidate = v9fs_lookup_revalidate,
101 	.d_delete = v9fs_cached_dentry_delete,
102 	.d_release = v9fs_dentry_release,
103 };
104 
105 const struct dentry_operations v9fs_dentry_operations = {
106 	.d_delete = always_delete_dentry,
107 	.d_release = v9fs_dentry_release,
108 };
109