Commit | Line | Data |
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3ed8491c EVH |
1 | /* |
2 | * V9FS FID Management | |
3 | * | |
ba17674f | 4 | * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net> |
46f6dac2 | 5 | * Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com> |
3ed8491c EVH |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
42e8c509 EVH |
8 | * it under the terms of the GNU General Public License version 2 |
9 | * as published by the Free Software Foundation. | |
3ed8491c EVH |
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 | ||
3ed8491c EVH |
24 | #include <linux/module.h> |
25 | #include <linux/errno.h> | |
26 | #include <linux/fs.h> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
914e2637 | 28 | #include <linux/sched.h> |
3ed8491c | 29 | #include <linux/idr.h> |
bd238fb4 LI |
30 | #include <net/9p/9p.h> |
31 | #include <net/9p/client.h> | |
3ed8491c | 32 | |
3ed8491c | 33 | #include "v9fs.h" |
3ed8491c | 34 | #include "v9fs_vfs.h" |
3ed8491c EVH |
35 | #include "fid.h" |
36 | ||
37 | /** | |
ba17674f LI |
38 | * v9fs_fid_add - add a fid to a dentry |
39 | * @dentry: dentry that the fid is being added to | |
3ed8491c | 40 | * @fid: fid to add |
3ed8491c EVH |
41 | * |
42 | */ | |
43 | ||
bd238fb4 | 44 | int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid) |
3ed8491c | 45 | { |
bd238fb4 | 46 | struct v9fs_dentry *dent; |
3ed8491c | 47 | |
bd238fb4 | 48 | P9_DPRINTK(P9_DEBUG_VFS, "fid %d dentry %s\n", |
7dd0cdc5 | 49 | fid->fid, dentry->d_name.name); |
3ed8491c | 50 | |
bd238fb4 LI |
51 | dent = dentry->d_fsdata; |
52 | if (!dent) { | |
53 | dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL); | |
54 | if (!dent) | |
55 | return -ENOMEM; | |
3ed8491c | 56 | |
bd238fb4 LI |
57 | spin_lock_init(&dent->lock); |
58 | INIT_LIST_HEAD(&dent->fidlist); | |
59 | dentry->d_fsdata = dent; | |
3ed8491c EVH |
60 | } |
61 | ||
bd238fb4 LI |
62 | spin_lock(&dent->lock); |
63 | list_add(&fid->dlist, &dent->fidlist); | |
64 | spin_unlock(&dent->lock); | |
3ed8491c | 65 | |
bd238fb4 | 66 | return 0; |
3ed8491c EVH |
67 | } |
68 | ||
69 | /** | |
ba17674f | 70 | * v9fs_fid_find - retrieve a fid that belongs to the specified uid |
3ed8491c | 71 | * @dentry: dentry to look for fid in |
ba17674f LI |
72 | * @uid: return fid that belongs to the specified user |
73 | * @any: if non-zero, return any fid associated with the dentry | |
3ed8491c EVH |
74 | * |
75 | */ | |
76 | ||
ba17674f | 77 | static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any) |
3ed8491c | 78 | { |
bd238fb4 | 79 | struct v9fs_dentry *dent; |
ba17674f LI |
80 | struct p9_fid *fid, *ret; |
81 | ||
82 | P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n", | |
7dd0cdc5 | 83 | dentry->d_name.name, dentry, uid, any); |
ba17674f LI |
84 | dent = (struct v9fs_dentry *) dentry->d_fsdata; |
85 | ret = NULL; | |
86 | if (dent) { | |
87 | spin_lock(&dent->lock); | |
88 | list_for_each_entry(fid, &dent->fidlist, dlist) { | |
89 | if (any || fid->uid == uid) { | |
90 | ret = fid; | |
91 | break; | |
92 | } | |
93 | } | |
94 | spin_unlock(&dent->lock); | |
95 | } | |
bd238fb4 | 96 | |
ba17674f | 97 | return ret; |
bd238fb4 | 98 | } |
3ed8491c | 99 | |
da977b2c | 100 | /** |
ba17674f | 101 | * v9fs_fid_lookup - lookup for a fid, try to walk if not found |
da977b2c EVH |
102 | * @dentry: dentry to look for fid in |
103 | * | |
ba17674f LI |
104 | * Look for a fid in the specified dentry for the current user. |
105 | * If no fid is found, try to create one walking from a fid from the parent | |
106 | * dentry (if it has one), or the root dentry. If the user haven't accessed | |
107 | * the fs yet, attach now and walk from the root. | |
da977b2c EVH |
108 | */ |
109 | ||
ba17674f | 110 | struct p9_fid *v9fs_fid_lookup(struct dentry *dentry) |
da977b2c | 111 | { |
ba17674f LI |
112 | int i, n, l, clone, any, access; |
113 | u32 uid; | |
5b0fa207 | 114 | struct p9_fid *fid, *old_fid = NULL; |
ba17674f LI |
115 | struct dentry *d, *ds; |
116 | struct v9fs_session_info *v9ses; | |
117 | char **wnames, *uname; | |
118 | ||
119 | v9ses = v9fs_inode2v9ses(dentry->d_inode); | |
120 | access = v9ses->flags & V9FS_ACCESS_MASK; | |
121 | switch (access) { | |
122 | case V9FS_ACCESS_SINGLE: | |
123 | case V9FS_ACCESS_USER: | |
f8b9d53a | 124 | uid = current_fsuid(); |
ba17674f LI |
125 | any = 0; |
126 | break; | |
127 | ||
128 | case V9FS_ACCESS_ANY: | |
129 | uid = v9ses->uid; | |
130 | any = 1; | |
131 | break; | |
132 | ||
133 | default: | |
134 | uid = ~0; | |
135 | any = 0; | |
136 | break; | |
137 | } | |
da977b2c | 138 | |
ba17674f LI |
139 | fid = v9fs_fid_find(dentry, uid, any); |
140 | if (fid) | |
141 | return fid; | |
142 | ||
143 | ds = dentry->d_parent; | |
144 | fid = v9fs_fid_find(ds, uid, any); | |
145 | if (!fid) { /* walk from the root */ | |
146 | n = 0; | |
147 | for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent) | |
148 | n++; | |
149 | ||
150 | fid = v9fs_fid_find(ds, uid, any); | |
151 | if (!fid) { /* the user is not attached to the fs yet */ | |
152 | if (access == V9FS_ACCESS_SINGLE) | |
153 | return ERR_PTR(-EPERM); | |
154 | ||
dd6102fb | 155 | if (v9fs_proto_dotu(v9ses)) |
ba17674f LI |
156 | uname = NULL; |
157 | else | |
158 | uname = v9ses->uname; | |
159 | ||
160 | fid = p9_client_attach(v9ses->clnt, NULL, uname, uid, | |
161 | v9ses->aname); | |
162 | ||
163 | if (IS_ERR(fid)) | |
164 | return fid; | |
165 | ||
166 | v9fs_fid_add(ds, fid); | |
167 | } | |
168 | } else /* walk from the parent */ | |
169 | n = 1; | |
170 | ||
171 | if (ds == dentry) | |
172 | return fid; | |
173 | ||
174 | wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL); | |
175 | if (!wnames) | |
176 | return ERR_PTR(-ENOMEM); | |
177 | ||
c55703d8 | 178 | for (d = dentry, i = (n-1); i >= 0; i--, d = d->d_parent) |
ba17674f LI |
179 | wnames[i] = (char *) d->d_name.name; |
180 | ||
181 | clone = 1; | |
182 | i = 0; | |
183 | while (i < n) { | |
184 | l = min(n - i, P9_MAXWELEM); | |
185 | fid = p9_client_walk(fid, l, &wnames[i], clone); | |
c55703d8 | 186 | if (IS_ERR(fid)) { |
5b0fa207 AK |
187 | if (old_fid) { |
188 | /* | |
189 | * If we fail, clunk fid which are mapping | |
190 | * to path component and not the last component | |
191 | * of the path. | |
192 | */ | |
193 | p9_client_clunk(old_fid); | |
194 | } | |
ba17674f LI |
195 | kfree(wnames); |
196 | return fid; | |
197 | } | |
5b0fa207 | 198 | old_fid = fid; |
ba17674f LI |
199 | i += l; |
200 | clone = 0; | |
201 | } | |
da977b2c | 202 | |
ba17674f LI |
203 | kfree(wnames); |
204 | v9fs_fid_add(dentry, fid); | |
bd238fb4 | 205 | return fid; |
da977b2c | 206 | } |
ba17674f LI |
207 | |
208 | struct p9_fid *v9fs_fid_clone(struct dentry *dentry) | |
209 | { | |
210 | struct p9_fid *fid, *ret; | |
211 | ||
212 | fid = v9fs_fid_lookup(dentry); | |
213 | if (IS_ERR(fid)) | |
214 | return fid; | |
215 | ||
216 | ret = p9_client_walk(fid, 0, NULL, 1); | |
217 | return ret; | |
218 | } |