xref: /linux/fs/9p/vfs_file.c (revision 54a8a2220c936a47840c9a3d74910c5a56fae2ed) 
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/version.h>
36 #include <linux/list.h>
37 #include <asm/uaccess.h>
38 #include <linux/idr.h>
39 
40 #include "debug.h"
41 #include "v9fs.h"
42 #include "9p.h"
43 #include "v9fs_vfs.h"
44 #include "fid.h"
45 
46 /**
47  * v9fs_file_open - open a file (or directory)
48  * @inode: inode to be opened
49  * @file: file being opened
50  *
51  */
52 
53 int v9fs_file_open(struct inode *inode, struct file *file)
54 {
55 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
56 	struct v9fs_fid *v9fid, *fid;
57 	struct v9fs_fcall *fcall = NULL;
58 	int open_mode = 0;
59 	unsigned int iounit = 0;
60 	int newfid = -1;
61 	long result = -1;
62 
63 	dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
64 
65 	v9fid = v9fs_fid_get_created(file->f_dentry);
66 	if (!v9fid)
67 		v9fid = v9fs_fid_lookup(file->f_dentry);
68 
69 	if (!v9fid) {
70 		dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
71 		return -EBADF;
72 	}
73 
74 	if (!v9fid->fidcreate) {
75 		fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
76 		if (fid == NULL) {
77 			dprintk(DEBUG_ERROR, "Out of Memory\n");
78 			return -ENOMEM;
79 		}
80 
81 		fid->fidopen = 0;
82 		fid->fidcreate = 0;
83 		fid->fidclunked = 0;
84 		fid->iounit = 0;
85 		fid->v9ses = v9ses;
86 
87 		newfid = v9fs_get_idpool(&v9ses->fidpool);
88 		if (newfid < 0) {
89 			eprintk(KERN_WARNING, "newfid fails!\n");
90 			return -ENOSPC;
91 		}
92 
93 		result =
94 		    v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);
95 
96 		if (result < 0) {
97 			v9fs_put_idpool(newfid, &v9ses->fidpool);
98 			dprintk(DEBUG_ERROR, "rewalk didn't work\n");
99 			return -EBADF;
100 		}
101 
102 		fid->fid = newfid;
103 		v9fid = fid;
104 		/* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
105 		/* translate open mode appropriately */
106 		open_mode = file->f_flags & 0x3;
107 
108 		if (file->f_flags & O_EXCL)
109 			open_mode |= V9FS_OEXCL;
110 
111 		if (v9ses->extended) {
112 			if (file->f_flags & O_TRUNC)
113 				open_mode |= V9FS_OTRUNC;
114 
115 			if (file->f_flags & O_APPEND)
116 				open_mode |= V9FS_OAPPEND;
117 		}
118 
119 		result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
120 		if (result < 0) {
121 			dprintk(DEBUG_ERROR,
122 				"open failed, open_mode 0x%x: %s\n", open_mode,
123 				FCALL_ERROR(fcall));
124 			kfree(fcall);
125 			return result;
126 		}
127 
128 		iounit = fcall->params.ropen.iounit;
129 		kfree(fcall);
130 	} else {
131 		/* create case */
132 		newfid = v9fid->fid;
133 		iounit = v9fid->iounit;
134 		v9fid->fidcreate = 0;
135 	}
136 
137 	file->private_data = v9fid;
138 
139 	v9fid->rdir_pos = 0;
140 	v9fid->rdir_fcall = NULL;
141 	v9fid->fidopen = 1;
142 	v9fid->filp = file;
143 	v9fid->iounit = iounit;
144 
145 	return 0;
146 }
147 
148 /**
149  * v9fs_file_lock - lock a file (or directory)
150  * @inode: inode to be opened
151  * @file: file being opened
152  *
153  * XXX - this looks like a local only lock, we should extend into 9P
154  *       by using open exclusive
155  */
156 
157 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
158 {
159 	int res = 0;
160 	struct inode *inode = filp->f_dentry->d_inode;
161 
162 	dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
163 
164 	/* No mandatory locks */
165 	if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
166 		return -ENOLCK;
167 
168 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
169 		filemap_fdatawrite(inode->i_mapping);
170 		filemap_fdatawait(inode->i_mapping);
171 		invalidate_inode_pages(&inode->i_data);
172 	}
173 
174 	return res;
175 }
176 
177 /**
178  * v9fs_read - read from a file (internal)
179  * @filep: file pointer to read
180  * @data: data buffer to read data into
181  * @count: size of buffer
182  * @offset: offset at which to read data
183  *
184  */
185 
186 static ssize_t
187 v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
188 {
189 	struct inode *inode = filp->f_dentry->d_inode;
190 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
191 	struct v9fs_fid *v9f = filp->private_data;
192 	struct v9fs_fcall *fcall = NULL;
193 	int fid = v9f->fid;
194 	int rsize = 0;
195 	int result = 0;
196 	int total = 0;
197 
198 	dprintk(DEBUG_VFS, "\n");
199 
200 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
201 	if (v9f->iounit != 0 && rsize > v9f->iounit)
202 		rsize = v9f->iounit;
203 
204 	do {
205 		if (count < rsize)
206 			rsize = count;
207 
208 		result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
209 
210 		if (result < 0) {
211 			printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
212 			       result);
213 
214 			kfree(fcall);
215 			return total;
216 		} else
217 			*offset += result;
218 
219 		/* XXX - extra copy */
220 		memcpy(buffer, fcall->params.rread.data, result);
221 		count -= result;
222 		buffer += result;
223 		total += result;
224 
225 		kfree(fcall);
226 
227 		if (result < rsize)
228 			break;
229 	} while (count);
230 
231 	return total;
232 }
233 
234 /**
235  * v9fs_file_read - read from a file
236  * @filep: file pointer to read
237  * @data: data buffer to read data into
238  * @count: size of buffer
239  * @offset: offset at which to read data
240  *
241  */
242 
243 static ssize_t
244 v9fs_file_read(struct file *filp, char __user * data, size_t count,
245 	       loff_t * offset)
246 {
247 	int retval = -1;
248 	int ret = 0;
249 	char *buffer;
250 
251 	buffer = kmalloc(count, GFP_KERNEL);
252 	if (!buffer)
253 		return -ENOMEM;
254 
255 	retval = v9fs_read(filp, buffer, count, offset);
256 	if (retval > 0) {
257 		if ((ret = copy_to_user(data, buffer, retval)) != 0) {
258 			dprintk(DEBUG_ERROR, "Problem copying to user %d\n",
259 				ret);
260 			retval = ret;
261 		}
262 	}
263 
264 	kfree(buffer);
265 
266 	return retval;
267 }
268 
269 /**
270  * v9fs_write - write to a file
271  * @filep: file pointer to write
272  * @data: data buffer to write data from
273  * @count: size of buffer
274  * @offset: offset at which to write data
275  *
276  */
277 
278 static ssize_t
279 v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset)
280 {
281 	struct inode *inode = filp->f_dentry->d_inode;
282 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
283 	struct v9fs_fid *v9fid = filp->private_data;
284 	struct v9fs_fcall *fcall;
285 	int fid = v9fid->fid;
286 	int result = -EIO;
287 	int rsize = 0;
288 	int total = 0;
289 
290 	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count,
291 		(int)*offset);
292 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
293 	if (v9fid->iounit != 0 && rsize > v9fid->iounit)
294 		rsize = v9fid->iounit;
295 
296 	dump_data(buffer, count);
297 
298 	do {
299 		if (count < rsize)
300 			rsize = count;
301 
302 		result =
303 		    v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall);
304 		if (result < 0) {
305 			eprintk(KERN_ERR, "error while writing: %s(%d)\n",
306 				FCALL_ERROR(fcall), result);
307 			kfree(fcall);
308 			return result;
309 		} else
310 			*offset += result;
311 
312 		kfree(fcall);
313 
314 		if (result != rsize) {
315 			eprintk(KERN_ERR,
316 				"short write: v9fs_t_write returned %d\n",
317 				result);
318 			break;
319 		}
320 
321 		count -= result;
322 		buffer += result;
323 		total += result;
324 	} while (count);
325 
326 	return total;
327 }
328 
329 /**
330  * v9fs_file_write - write to a file
331  * @filep: file pointer to write
332  * @data: data buffer to write data from
333  * @count: size of buffer
334  * @offset: offset at which to write data
335  *
336  */
337 
338 static ssize_t
339 v9fs_file_write(struct file *filp, const char __user * data,
340 		size_t count, loff_t * offset)
341 {
342 	int ret = -1;
343 	char *buffer;
344 
345 	buffer = kmalloc(count, GFP_KERNEL);
346 	if (buffer == NULL)
347 		return -ENOMEM;
348 
349 	ret = copy_from_user(buffer, data, count);
350 	if (ret) {
351 		dprintk(DEBUG_ERROR, "Problem copying from user\n");
352 		ret = -EFAULT;
353 	} else {
354 		ret = v9fs_write(filp, buffer, count, offset);
355 	}
356 
357 	kfree(buffer);
358 
359 	return ret;
360 }
361 
362 struct file_operations v9fs_file_operations = {
363 	.llseek = generic_file_llseek,
364 	.read = v9fs_file_read,
365 	.write = v9fs_file_write,
366 	.open = v9fs_file_open,
367 	.release = v9fs_dir_release,
368 	.lock = v9fs_file_lock,
369 };
370