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3ed8491c EVH |
1 | /* |
2 | * V9FS FID Management | |
3 | * | |
4 | * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to: | |
18 | * Free Software Foundation | |
19 | * 51 Franklin Street, Fifth Floor | |
20 | * Boston, MA 02111-1301 USA | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <linux/config.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/idr.h> | |
29 | ||
30 | #include "debug.h" | |
31 | #include "v9fs.h" | |
32 | #include "9p.h" | |
33 | #include "v9fs_vfs.h" | |
3ed8491c EVH |
34 | #include "fid.h" |
35 | ||
36 | /** | |
37 | * v9fs_fid_insert - add a fid to a dentry | |
38 | * @fid: fid to add | |
39 | * @dentry: dentry that it is being added to | |
40 | * | |
41 | */ | |
42 | ||
6a3124a3 | 43 | int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry) |
3ed8491c EVH |
44 | { |
45 | struct list_head *fid_list = (struct list_head *)dentry->d_fsdata; | |
46 | dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid, | |
47 | dentry->d_iname, dentry); | |
48 | if (dentry->d_fsdata == NULL) { | |
49 | dentry->d_fsdata = | |
50 | kmalloc(sizeof(struct list_head), GFP_KERNEL); | |
51 | if (dentry->d_fsdata == NULL) { | |
52 | dprintk(DEBUG_ERROR, "Out of memory\n"); | |
53 | return -ENOMEM; | |
54 | } | |
55 | fid_list = (struct list_head *)dentry->d_fsdata; | |
56 | INIT_LIST_HEAD(fid_list); /* Initialize list head */ | |
57 | } | |
58 | ||
59 | fid->uid = current->uid; | |
60 | fid->pid = current->pid; | |
61 | list_add(&fid->list, fid_list); | |
62 | return 0; | |
63 | } | |
64 | ||
65 | /** | |
66 | * v9fs_fid_create - allocate a FID structure | |
67 | * @dentry - dentry to link newly created fid to | |
68 | * | |
69 | */ | |
70 | ||
6a3124a3 | 71 | struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid) |
3ed8491c EVH |
72 | { |
73 | struct v9fs_fid *new; | |
74 | ||
6a3124a3 | 75 | dprintk(DEBUG_9P, "fid create fid %d\n", fid); |
3ed8491c EVH |
76 | new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL); |
77 | if (new == NULL) { | |
78 | dprintk(DEBUG_ERROR, "Out of Memory\n"); | |
79 | return ERR_PTR(-ENOMEM); | |
80 | } | |
81 | ||
0b8dd177 LI |
82 | new->fid = fid; |
83 | new->v9ses = v9ses; | |
3ed8491c | 84 | new->fidopen = 0; |
3ed8491c EVH |
85 | new->fidclunked = 0; |
86 | new->iounit = 0; | |
0b8dd177 LI |
87 | new->rdir_pos = 0; |
88 | new->rdir_fcall = NULL; | |
6a3124a3 | 89 | INIT_LIST_HEAD(&new->list); |
3ed8491c | 90 | |
3ed8491c | 91 | return new; |
3ed8491c EVH |
92 | } |
93 | ||
94 | /** | |
95 | * v9fs_fid_destroy - deallocate a FID structure | |
96 | * @fid: fid to destroy | |
97 | * | |
98 | */ | |
99 | ||
100 | void v9fs_fid_destroy(struct v9fs_fid *fid) | |
101 | { | |
102 | list_del(&fid->list); | |
103 | kfree(fid); | |
104 | } | |
105 | ||
0b8dd177 LI |
106 | /** |
107 | * v9fs_fid_walk_up - walks from the process current directory | |
108 | * up to the specified dentry. | |
109 | */ | |
110 | static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry) | |
111 | { | |
112 | int fidnum, cfidnum, err; | |
6a3124a3 | 113 | struct v9fs_fid *cfid, *fid; |
0b8dd177 LI |
114 | struct dentry *cde; |
115 | struct v9fs_session_info *v9ses; | |
116 | ||
117 | v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode); | |
118 | cfid = v9fs_fid_lookup(current->fs->pwd); | |
119 | if (cfid == NULL) { | |
120 | dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n"); | |
121 | return ERR_PTR(-ENOENT); | |
122 | } | |
123 | ||
124 | cfidnum = cfid->fid; | |
125 | cde = current->fs->pwd; | |
126 | /* TODO: take advantage of multiwalk */ | |
127 | ||
128 | fidnum = v9fs_get_idpool(&v9ses->fidpool); | |
129 | if (fidnum < 0) { | |
130 | dprintk(DEBUG_ERROR, "could not get a new fid num\n"); | |
131 | err = -ENOENT; | |
132 | goto clunk_fid; | |
133 | } | |
134 | ||
135 | while (cde != dentry) { | |
136 | if (cde == cde->d_parent) { | |
137 | dprintk(DEBUG_ERROR, "can't find dentry\n"); | |
138 | err = -ENOENT; | |
139 | goto clunk_fid; | |
140 | } | |
141 | ||
142 | err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL); | |
143 | if (err < 0) { | |
144 | dprintk(DEBUG_ERROR, "problem walking to parent\n"); | |
145 | goto clunk_fid; | |
146 | } | |
147 | ||
148 | cfidnum = fidnum; | |
149 | cde = cde->d_parent; | |
150 | } | |
151 | ||
6a3124a3 LI |
152 | fid = v9fs_fid_create(v9ses, fidnum); |
153 | if (fid) { | |
154 | err = v9fs_fid_insert(fid, dentry); | |
155 | if (err < 0) { | |
156 | kfree(fid); | |
157 | goto clunk_fid; | |
158 | } | |
159 | } | |
160 | ||
161 | return fid; | |
0b8dd177 LI |
162 | |
163 | clunk_fid: | |
3cf6429a | 164 | v9fs_t_clunk(v9ses, fidnum); |
0b8dd177 LI |
165 | return ERR_PTR(err); |
166 | } | |
167 | ||
3ed8491c EVH |
168 | /** |
169 | * v9fs_fid_lookup - retrieve the right fid from a particular dentry | |
170 | * @dentry: dentry to look for fid in | |
171 | * @type: intent of lookup (operation or traversal) | |
172 | * | |
173 | * search list of fids associated with a dentry for a fid with a matching | |
174 | * thread id or uid. If that fails, look up the dentry's parents to see if you | |
175 | * can find a matching fid. | |
176 | * | |
177 | */ | |
178 | ||
0b8dd177 | 179 | struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry) |
3ed8491c EVH |
180 | { |
181 | struct list_head *fid_list = (struct list_head *)dentry->d_fsdata; | |
3ed8491c | 182 | struct v9fs_fid *return_fid = NULL; |
3ed8491c | 183 | |
0b8dd177 | 184 | dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry); |
3ed8491c | 185 | |
6a3124a3 LI |
186 | if (fid_list) |
187 | return_fid = list_entry(fid_list->next, struct v9fs_fid, list); | |
3ed8491c EVH |
188 | |
189 | if (!return_fid) { | |
190 | struct dentry *par = current->fs->pwd->d_parent; | |
191 | int count = 1; | |
192 | while (par != NULL) { | |
193 | if (par == dentry) | |
194 | break; | |
195 | count++; | |
196 | if (par == par->d_parent) { | |
197 | dprintk(DEBUG_ERROR, | |
198 | "got to root without finding dentry\n"); | |
199 | break; | |
200 | } | |
201 | par = par->d_parent; | |
202 | } | |
203 | ||
204 | /* XXX - there may be some duplication we can get rid of */ | |
205 | if (par == dentry) { | |
0b8dd177 LI |
206 | return_fid = v9fs_fid_walk_up(dentry); |
207 | if (IS_ERR(return_fid)) | |
208 | return_fid = NULL; | |
209 | } | |
210 | } | |
3ed8491c | 211 | |
0b8dd177 LI |
212 | return return_fid; |
213 | } |