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1 /*

2 * linux/fs/9p/vfs_dir.c

3 *

4 * This file contains vfs directory ops for the 9P2000 protocol.

5 *

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 */

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>

39 #include "v9fs.h"

40 #include "v9fs_vfs.h"

41 #include "fid.h"

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 */

54 struct p9_rdir {

55 struct mutex mutex;

56 int head;

57 int tail;

58 uint8_t *buf;

59 };

61 /**

62 * dt_type - return file type

63 * @mistat: mistat structure

64 *

65 */

67 static inline int dt_type(struct p9_wstat *mistat)

68 {

69 unsigned long perm = mistat->mode;

70 int rettype = DT_REG;

72 if (perm & P9_DMDIR)

73 rettype = DT_DIR;

74 if (perm & P9_DMSYMLINK)

75 rettype = DT_LNK;

77 return rettype;

78 }

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 }

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 */

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

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_DPRINTK(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(rdir->buf + rdir->head,

169 rdir->tail - rdir->head, &st,

170 fid->clnt->proto_version);

171 if (err) {

172 P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);

173 err = -EIO;

174 p9stat_free(&st);

175 goto unlock_and_exit;

176 }

177 reclen = st.size+2;

178

179 over = filldir(dirent, st.name, strlen(st.name),

180 filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));

181

182 p9stat_free(&st);

183

184 if (over) {

185 err = 0;

186 goto unlock_and_exit;

187 }

188 rdir->head += reclen;

189 filp->f_pos += reclen;

190 }

191 }

192

193 unlock_and_exit:

194 mutex_unlock(&rdir->mutex);

195 exit:

196 return err;

197 }

198

199 /**

200 * v9fs_dir_readdir_dotl - read a directory

201 * @filp: opened file structure

202 * @dirent: buffer to fill dirent structures

203 * @filldir: function to populate dirent structures

204 *

205 */

206 static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,

207 filldir_t filldir)

208 {

209 int over;

210 int err = 0;

211 struct p9_fid *fid;

212 int buflen;

213 struct p9_rdir *rdir;

214 struct p9_dirent curdirent;

215 u64 oldoffset = 0;

216

217 P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);

218 fid = filp->private_data;

219

220 buflen = fid->clnt->msize - P9_READDIRHDRSZ;

221

222 err = v9fs_alloc_rdir_buf(filp, buflen);

223 if (err)

224 goto exit;

225 rdir = (struct p9_rdir *) fid->rdir;

226

227 err = mutex_lock_interruptible(&rdir->mutex);

228 if (err)

229 return err;

230

231 while (err == 0) {

232 if (rdir->tail == rdir->head) {

233 err = p9_client_readdir(fid, rdir->buf, buflen,

234 filp->f_pos);

235 if (err <= 0)

236 goto unlock_and_exit;

237

238 rdir->head = 0;

239 rdir->tail = err;

240 }

241

242 while (rdir->head < rdir->tail) {

243

244 err = p9dirent_read(rdir->buf + rdir->head,

245 buflen - rdir->head, &curdirent,

246 fid->clnt->proto_version);

247 if (err < 0) {

248 P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);

249 err = -EIO;

250 goto unlock_and_exit;

251 }

252

253 /* d_off in dirent structure tracks the offset into

254 * the next dirent in the dir. However, filldir()

255 * expects offset into the current dirent. Hence

256 * while calling filldir send the offset from the

257 * previous dirent structure.

258 */

259 over = filldir(dirent, curdirent.d_name,

260 strlen(curdirent.d_name),

261 oldoffset, v9fs_qid2ino(&curdirent.qid),

262 curdirent.d_type);

263 oldoffset = curdirent.d_off;

264

265 if (over) {

266 err = 0;

267 goto unlock_and_exit;

268 }

269

270 filp->f_pos = curdirent.d_off;

271 rdir->head += err;

272 }

273 }

274

275 unlock_and_exit:

276 mutex_unlock(&rdir->mutex);

277 exit:

278 return err;

279 }

280

281

282 /**

283 * v9fs_dir_release - close a directory

284 * @inode: inode of the directory

285 * @filp: file pointer to a directory

286 *

287 */

288

289 int v9fs_dir_release(struct inode *inode, struct file *filp)

290 {

291 struct p9_fid *fid;

292

293 fid = filp->private_data;

294 P9_DPRINTK(P9_DEBUG_VFS,

295 "v9fs_dir_release: inode: %p filp: %p fid: %d\n",

296 inode, filp, fid ? fid->fid : -1);

297 filemap_write_and_wait(inode->i_mapping);

298 if (fid)

299 p9_client_clunk(fid);

300 return 0;

301 }

302

303 const struct file_operations v9fs_dir_operations = {

304 .read = generic_read_dir,

305 .llseek = generic_file_llseek,

306 .readdir = v9fs_dir_readdir,

307 .open = v9fs_file_open,

308 .release = v9fs_dir_release,

309 };

310

311 const struct file_operations v9fs_dir_operations_dotl = {

312 .read = generic_read_dir,

313 .llseek = generic_file_llseek,

314 .readdir = v9fs_dir_readdir_dotl,

315 .open = v9fs_file_open,

316 .release = v9fs_dir_release,

317 };