1 /*
2 * linux/fs/9p/vfs_dir.c
3 *
4 * This file contains vfs directory 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 version 2
11 * as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to:
20 * Free Software Foundation
21 * 51 Franklin Street, Fifth Floor
22 * Boston, MA 02111-1301 USA
23 *
24 */
25
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/file.h>
30 #include <linux/stat.h>
31 #include <linux/string.h>
32 #include <linux/sched.h>
33 #include <linux/inet.h>
34 #include <linux/idr.h>
35 #include <linux/slab.h>
36 #include <net/9p/9p.h>
37 #include <net/9p/client.h>
38
39 #include "v9fs.h"
40 #include "v9fs_vfs.h"
41 #include "fid.h"
42
43 /**
44 * struct p9_rdir - readdir accounting
45 * @mutex: mutex protecting readdir
46 * @head: start offset of current dirread buffer
47 * @tail: end offset of current dirread buffer
48 * @buf: dirread buffer
49 *
50 * private structure for keeping track of readdir
51 * allocated on demand
52 */
53
54 struct p9_rdir {
55 struct mutex mutex;
56 int head;
57 int tail;
58 uint8_t *buf;
59 };
60
61 /**
62 * dt_type - return file type
63 * @mistat: mistat structure
64 *
65 */
66
dt_type(struct p9_wstat * mistat)67 static inline int dt_type(struct p9_wstat *mistat)
68 {
69 unsigned long perm = mistat->mode;
70 int rettype = DT_REG;
71
72 if (perm & P9_DMDIR)
73 rettype = DT_DIR;
74 if (perm & P9_DMSYMLINK)
75 rettype = DT_LNK;
76
77 return rettype;
78 }
79
p9stat_init(struct p9_wstat * stbuf)80 static void p9stat_init(struct p9_wstat *stbuf)
81 {
82 stbuf->name = NULL;
83 stbuf->uid = NULL;
84 stbuf->gid = NULL;
85 stbuf->muid = NULL;
86 stbuf->extension = NULL;
87 }
88
89 /**
90 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
91 * @filp: opened file structure
92 * @buflen: Length in bytes of buffer to allocate
93 *
94 */
95
v9fs_alloc_rdir_buf(struct file * filp,int buflen)96 static int v9fs_alloc_rdir_buf(struct file *filp, int buflen)
97 {
98 struct p9_rdir *rdir;
99 struct p9_fid *fid;
100 int err = 0;
101
102 fid = filp->private_data;
103 if (!fid->rdir) {
104 rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
105
106 if (rdir == NULL) {
107 err = -ENOMEM;
108 goto exit;
109 }
110 spin_lock(&filp->f_dentry->d_lock);
111 if (!fid->rdir) {
112 rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
113 mutex_init(&rdir->mutex);
114 rdir->head = rdir->tail = 0;
115 fid->rdir = (void *) rdir;
116 rdir = NULL;
117 }
118 spin_unlock(&filp->f_dentry->d_lock);
119 kfree(rdir);
120 }
121 exit:
122 return err;
123 }
124
125 /**
126 * v9fs_dir_readdir - read a directory
127 * @filp: opened file structure
128 * @dirent: directory structure ???
129 * @filldir: function to populate directory structure ???
130 *
131 */
132
v9fs_dir_readdir(struct file * filp,void * dirent,filldir_t filldir)133 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
134 {
135 int over;
136 struct p9_wstat st;
137 int err = 0;
138 struct p9_fid *fid;
139 int buflen;
140 int reclen = 0;
141 struct p9_rdir *rdir;
142
143 p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
144 fid = filp->private_data;
145
146 buflen = fid->clnt->msize - P9_IOHDRSZ;
147
148 err = v9fs_alloc_rdir_buf(filp, buflen);
149 if (err)
150 goto exit;
151 rdir = (struct p9_rdir *) fid->rdir;
152
153 err = mutex_lock_interruptible(&rdir->mutex);
154 if (err)
155 return err;
156 while (err == 0) {
157 if (rdir->tail == rdir->head) {
158 err = v9fs_file_readn(filp, rdir->buf, NULL,
159 buflen, filp->f_pos);
160 if (err <= 0)
161 goto unlock_and_exit;
162
163 rdir->head = 0;
164 rdir->tail = err;
165 }
166 while (rdir->head < rdir->tail) {
167 p9stat_init(&st);
168 err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
169 rdir->tail - rdir->head, &st);
170 if (err) {
171 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
172 err = -EIO;
173 p9stat_free(&st);
174 goto unlock_and_exit;
175 }
176 reclen = st.size+2;
177
178 over = filldir(dirent, st.name, strlen(st.name),
179 filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
180
181 p9stat_free(&st);
182
183 if (over) {
184 err = 0;
185 goto unlock_and_exit;
186 }
187 rdir->head += reclen;
188 filp->f_pos += reclen;
189 }
190 }
191
192 unlock_and_exit:
193 mutex_unlock(&rdir->mutex);
194 exit:
195 return err;
196 }
197
198 /**
199 * v9fs_dir_readdir_dotl - read a directory
200 * @filp: opened file structure
201 * @dirent: buffer to fill dirent structures
202 * @filldir: function to populate dirent structures
203 *
204 */
v9fs_dir_readdir_dotl(struct file * filp,void * dirent,filldir_t filldir)205 static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,
206 filldir_t filldir)
207 {
208 int over;
209 int err = 0;
210 struct p9_fid *fid;
211 int buflen;
212 struct p9_rdir *rdir;
213 struct p9_dirent curdirent;
214 u64 oldoffset = 0;
215
216 p9_debug(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
217 fid = filp->private_data;
218
219 buflen = fid->clnt->msize - P9_READDIRHDRSZ;
220
221 err = v9fs_alloc_rdir_buf(filp, buflen);
222 if (err)
223 goto exit;
224 rdir = (struct p9_rdir *) fid->rdir;
225
226 err = mutex_lock_interruptible(&rdir->mutex);
227 if (err)
228 return err;
229
230 while (err == 0) {
231 if (rdir->tail == rdir->head) {
232 err = p9_client_readdir(fid, rdir->buf, buflen,
233 filp->f_pos);
234 if (err <= 0)
235 goto unlock_and_exit;
236
237 rdir->head = 0;
238 rdir->tail = err;
239 }
240
241 while (rdir->head < rdir->tail) {
242
243 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
244 rdir->tail - rdir->head,
245 &curdirent);
246 if (err < 0) {
247 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
248 err = -EIO;
249 goto unlock_and_exit;
250 }
251
252 /* d_off in dirent structure tracks the offset into
253 * the next dirent in the dir. However, filldir()
254 * expects offset into the current dirent. Hence
255 * while calling filldir send the offset from the
256 * previous dirent structure.
257 */
258 over = filldir(dirent, curdirent.d_name,
259 strlen(curdirent.d_name),
260 oldoffset, v9fs_qid2ino(&curdirent.qid),
261 curdirent.d_type);
262 oldoffset = curdirent.d_off;
263
264 if (over) {
265 err = 0;
266 goto unlock_and_exit;
267 }
268
269 filp->f_pos = curdirent.d_off;
270 rdir->head += err;
271 }
272 }
273
274 unlock_and_exit:
275 mutex_unlock(&rdir->mutex);
276 exit:
277 return err;
278 }
279
280
281 /**
282 * v9fs_dir_release - close a directory
283 * @inode: inode of the directory
284 * @filp: file pointer to a directory
285 *
286 */
287
v9fs_dir_release(struct inode * inode,struct file * filp)288 int v9fs_dir_release(struct inode *inode, struct file *filp)
289 {
290 struct p9_fid *fid;
291
292 fid = filp->private_data;
293 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
294 inode, filp, fid ? fid->fid : -1);
295 if (fid)
296 p9_client_clunk(fid);
297 return 0;
298 }
299
300 const struct file_operations v9fs_dir_operations = {
301 .read = generic_read_dir,
302 .llseek = generic_file_llseek,
303 .readdir = v9fs_dir_readdir,
304 .open = v9fs_file_open,
305 .release = v9fs_dir_release,
306 };
307
308 const struct file_operations v9fs_dir_operations_dotl = {
309 .read = generic_read_dir,
310 .llseek = generic_file_llseek,
311 .readdir = v9fs_dir_readdir_dotl,
312 .open = v9fs_file_open,
313 .release = v9fs_dir_release,
314 .fsync = v9fs_file_fsync_dotl,
315 };
316