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e69e7fe5 EVH |
1 | /* |
2 | * linux/fs/9p/vfs_dentry.c | |
3 | * | |
4 | * This file contians vfs dentry ops for the 9P2000 protocol. | |
5 | * | |
6 | * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> | |
7 | * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to: | |
21 | * Free Software Foundation | |
22 | * 51 Franklin Street, Fifth Floor | |
23 | * Boston, MA 02111-1301 USA | |
24 | * | |
25 | */ | |
26 | ||
27 | #include <linux/module.h> | |
28 | #include <linux/errno.h> | |
29 | #include <linux/fs.h> | |
30 | #include <linux/file.h> | |
31 | #include <linux/pagemap.h> | |
32 | #include <linux/stat.h> | |
33 | #include <linux/string.h> | |
34 | #include <linux/smp_lock.h> | |
35 | #include <linux/inet.h> | |
36 | #include <linux/namei.h> | |
37 | #include <linux/idr.h> | |
38 | ||
39 | #include "debug.h" | |
40 | #include "v9fs.h" | |
41 | #include "9p.h" | |
42 | #include "v9fs_vfs.h" | |
e69e7fe5 EVH |
43 | #include "fid.h" |
44 | ||
45 | /** | |
46 | * v9fs_dentry_validate - VFS dcache hook to validate cache | |
47 | * @dentry: dentry that is being validated | |
48 | * @nd: path data | |
49 | * | |
50 | * dcache really shouldn't be used for 9P2000 as at all due to | |
51 | * potential attached semantics to directory traversal (walk). | |
52 | * | |
53 | * FUTURE: look into how to use dcache to allow multi-stage | |
54 | * walks in Plan 9 & potential for better dcache operation which | |
55 | * would remain valid for Plan 9 semantics. Older versions | |
56 | * had validation via stat for those interested. However, since | |
57 | * stat has the same approximate overhead as walk there really | |
58 | * is no difference. The only improvement would be from a | |
59 | * time-decay cache like NFS has and that undermines the | |
60 | * synchronous nature of 9P2000. | |
61 | * | |
62 | */ | |
63 | ||
64 | static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd) | |
65 | { | |
66 | struct dentry *dc = current->fs->pwd; | |
67 | ||
68 | dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry); | |
0b8dd177 | 69 | if (v9fs_fid_lookup(dentry)) { |
e69e7fe5 EVH |
70 | dprintk(DEBUG_VFS, "VALID\n"); |
71 | return 1; | |
72 | } | |
73 | ||
74 | while (dc != NULL) { | |
75 | if (dc == dentry) { | |
76 | dprintk(DEBUG_VFS, "VALID\n"); | |
77 | return 1; | |
78 | } | |
79 | if (dc == dc->d_parent) | |
80 | break; | |
81 | ||
82 | dc = dc->d_parent; | |
83 | } | |
84 | ||
85 | dprintk(DEBUG_VFS, "INVALID\n"); | |
86 | return 0; | |
87 | } | |
88 | ||
89 | /** | |
90 | * v9fs_dentry_release - called when dentry is going to be freed | |
91 | * @dentry: dentry that is being release | |
92 | * | |
93 | */ | |
94 | ||
95 | void v9fs_dentry_release(struct dentry *dentry) | |
96 | { | |
3cf6429a LI |
97 | int err; |
98 | ||
e69e7fe5 EVH |
99 | dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry); |
100 | ||
101 | if (dentry->d_fsdata != NULL) { | |
102 | struct list_head *fid_list = dentry->d_fsdata; | |
103 | struct v9fs_fid *temp = NULL; | |
104 | struct v9fs_fid *current_fid = NULL; | |
e69e7fe5 EVH |
105 | |
106 | list_for_each_entry_safe(current_fid, temp, fid_list, list) { | |
3cf6429a | 107 | err = v9fs_t_clunk(current_fid->v9ses, current_fid->fid); |
e69e7fe5 | 108 | |
3cf6429a | 109 | if (err < 0) |
531b1094 LI |
110 | dprintk(DEBUG_ERROR, "clunk failed: %d name %s\n", |
111 | err, dentry->d_iname); | |
e69e7fe5 | 112 | |
e69e7fe5 EVH |
113 | v9fs_fid_destroy(current_fid); |
114 | } | |
115 | ||
116 | kfree(dentry->d_fsdata); /* free the list_head */ | |
117 | } | |
118 | } | |
119 | ||
120 | struct dentry_operations v9fs_dentry_operations = { | |
121 | .d_revalidate = v9fs_dentry_validate, | |
122 | .d_release = v9fs_dentry_release, | |
123 | }; |