e13577da913020616706d3a231a8c9ceac1b6bbf
[linux-2.6.git] / fs / 9p / vfs_file.c
1 /*
2  *  linux/fs/9p/vfs_file.c
3  *
4  * This file contians vfs file ops for 9P2000.
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/stat.h>
32 #include <linux/string.h>
33 #include <linux/smp_lock.h>
34 #include <linux/inet.h>
35 #include <linux/list.h>
36 #include <asm/uaccess.h>
37 #include <linux/idr.h>
38
39 #include "debug.h"
40 #include "v9fs.h"
41 #include "9p.h"
42 #include "v9fs_vfs.h"
43 #include "fid.h"
44
45 /**
46  * v9fs_file_open - open a file (or directory)
47  * @inode: inode to be opened
48  * @file: file being opened
49  *
50  */
51
52 int v9fs_file_open(struct inode *inode, struct file *file)
53 {
54         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
55         struct v9fs_fid *v9fid, *fid;
56         struct v9fs_fcall *fcall = NULL;
57         int open_mode = 0;
58         unsigned int iounit = 0;
59         int newfid = -1;
60         long result = -1;
61
62         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
63
64         v9fid = v9fs_fid_get_created(file->f_dentry);
65         if (!v9fid)
66                 v9fid = v9fs_fid_lookup(file->f_dentry);
67
68         if (!v9fid) {
69                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
70                 return -EBADF;
71         }
72
73         if (!v9fid->fidcreate) {
74                 fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
75                 if (fid == NULL) {
76                         dprintk(DEBUG_ERROR, "Out of Memory\n");
77                         return -ENOMEM;
78                 }
79
80                 fid->fidopen = 0;
81                 fid->fidcreate = 0;
82                 fid->fidclunked = 0;
83                 fid->iounit = 0;
84                 fid->v9ses = v9ses;
85
86                 newfid = v9fs_get_idpool(&v9ses->fidpool);
87                 if (newfid < 0) {
88                         eprintk(KERN_WARNING, "newfid fails!\n");
89                         return -ENOSPC;
90                 }
91
92                 result =
93                     v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);
94
95                 if (result < 0) {
96                         v9fs_put_idpool(newfid, &v9ses->fidpool);
97                         dprintk(DEBUG_ERROR, "rewalk didn't work\n");
98                         return -EBADF;
99                 }
100
101                 fid->fid = newfid;
102                 v9fid = fid;
103                 /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
104                 /* translate open mode appropriately */
105                 open_mode = file->f_flags & 0x3;
106
107                 if (file->f_flags & O_EXCL)
108                         open_mode |= V9FS_OEXCL;
109
110                 if (v9ses->extended) {
111                         if (file->f_flags & O_TRUNC)
112                                 open_mode |= V9FS_OTRUNC;
113
114                         if (file->f_flags & O_APPEND)
115                                 open_mode |= V9FS_OAPPEND;
116                 }
117
118                 result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
119                 if (result < 0) {
120                         dprintk(DEBUG_ERROR,
121                                 "open failed, open_mode 0x%x: %s\n", open_mode,
122                                 FCALL_ERROR(fcall));
123                         kfree(fcall);
124                         return result;
125                 }
126
127                 iounit = fcall->params.ropen.iounit;
128                 kfree(fcall);
129         } else {
130                 /* create case */
131                 newfid = v9fid->fid;
132                 iounit = v9fid->iounit;
133                 v9fid->fidcreate = 0;
134         }
135
136         file->private_data = v9fid;
137
138         v9fid->rdir_pos = 0;
139         v9fid->rdir_fcall = NULL;
140         v9fid->fidopen = 1;
141         v9fid->filp = file;
142         v9fid->iounit = iounit;
143
144         return 0;
145 }
146
147 /**
148  * v9fs_file_lock - lock a file (or directory)
149  * @inode: inode to be opened
150  * @file: file being opened
151  *
152  * XXX - this looks like a local only lock, we should extend into 9P
153  *       by using open exclusive
154  */
155
156 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
157 {
158         int res = 0;
159         struct inode *inode = filp->f_dentry->d_inode;
160
161         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
162
163         /* No mandatory locks */
164         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
165                 return -ENOLCK;
166
167         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
168                 filemap_write_and_wait(inode->i_mapping);
169                 invalidate_inode_pages(&inode->i_data);
170         }
171
172         return res;
173 }
174
175 /**
176  * v9fs_file_read - read from a file
177  * @filep: file pointer to read
178  * @data: data buffer to read data into
179  * @count: size of buffer
180  * @offset: offset at which to read data
181  *
182  */
183 static ssize_t
184 v9fs_file_read(struct file *filp, char __user * data, size_t count,
185                loff_t * offset)
186 {
187         struct inode *inode = filp->f_dentry->d_inode;
188         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
189         struct v9fs_fid *v9f = filp->private_data;
190         struct v9fs_fcall *fcall = NULL;
191         int fid = v9f->fid;
192         int rsize = 0;
193         int result = 0;
194         int total = 0;
195         int n;
196
197         dprintk(DEBUG_VFS, "\n");
198
199         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
200         if (v9f->iounit != 0 && rsize > v9f->iounit)
201                 rsize = v9f->iounit;
202
203         do {
204                 if (count < rsize)
205                         rsize = count;
206
207                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
208
209                 if (result < 0) {
210                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
211                                result);
212
213                         kfree(fcall);
214                         return total;
215                 } else
216                         *offset += result;
217
218                 n = copy_to_user(data, fcall->params.rread.data, result);
219                 if (n) {
220                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
221                         kfree(fcall);
222                         return -EFAULT;
223                 }
224
225                 count -= result;
226                 data += result;
227                 total += result;
228
229                 kfree(fcall);
230
231                 if (result < rsize)
232                         break;
233         } while (count);
234
235         return total;
236 }
237
238 /**
239  * v9fs_file_write - write to a file
240  * @filep: file pointer to write
241  * @data: data buffer to write data from
242  * @count: size of buffer
243  * @offset: offset at which to write data
244  *
245  */
246
247 static ssize_t
248 v9fs_file_write(struct file *filp, const char __user * data,
249                 size_t count, loff_t * offset)
250 {
251         struct inode *inode = filp->f_dentry->d_inode;
252         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
253         struct v9fs_fid *v9fid = filp->private_data;
254         struct v9fs_fcall *fcall;
255         int fid = v9fid->fid;
256         int result = -EIO;
257         int rsize = 0;
258         int total = 0;
259         char *buf;
260
261         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
262                 (int)*offset);
263         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
264         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
265                 rsize = v9fid->iounit;
266
267         buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL);
268         if (!buf)
269                 return -ENOMEM;
270
271         do {
272                 if (count < rsize)
273                         rsize = count;
274
275                 result = copy_from_user(buf, data, rsize);
276                 if (result) {
277                         dprintk(DEBUG_ERROR, "Problem copying from user\n");
278                         kfree(buf);
279                         return -EFAULT;
280                 }
281
282                 dump_data(buf, rsize);
283                 result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall);
284                 if (result < 0) {
285                         eprintk(KERN_ERR, "error while writing: %s(%d)\n",
286                                 FCALL_ERROR(fcall), result);
287                         kfree(fcall);
288                         kfree(buf);
289                         return result;
290                 } else
291                         *offset += result;
292
293                 kfree(fcall);
294                 fcall = NULL;
295
296                 if (result != rsize) {
297                         eprintk(KERN_ERR,
298                                 "short write: v9fs_t_write returned %d\n",
299                                 result);
300                         break;
301                 }
302
303                 count -= result;
304                 data += result;
305                 total += result;
306         } while (count);
307
308         kfree(buf);
309         return total;
310 }
311
312 struct file_operations v9fs_file_operations = {
313         .llseek = generic_file_llseek,
314         .read = v9fs_file_read,
315         .write = v9fs_file_write,
316         .open = v9fs_file_open,
317         .release = v9fs_dir_release,
318         .lock = v9fs_file_lock,
319 };