xref: /openbmc/linux/fs/9p/vfs_file.c (revision 87c2ce3b) 
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 			PRINT_FCALL_ERROR("open failed", fcall);
122 			kfree(fcall);
123 			return result;
124 		}
125 
126 		iounit = fcall->params.ropen.iounit;
127 		kfree(fcall);
128 	} else {
129 		/* create case */
130 		newfid = v9fid->fid;
131 		iounit = v9fid->iounit;
132 		v9fid->fidcreate = 0;
133 	}
134 
135 	file->private_data = v9fid;
136 
137 	v9fid->rdir_pos = 0;
138 	v9fid->rdir_fcall = NULL;
139 	v9fid->fidopen = 1;
140 	v9fid->filp = file;
141 	v9fid->iounit = iounit;
142 
143 	return 0;
144 }
145 
146 /**
147  * v9fs_file_lock - lock a file (or directory)
148  * @inode: inode to be opened
149  * @file: file being opened
150  *
151  * XXX - this looks like a local only lock, we should extend into 9P
152  *       by using open exclusive
153  */
154 
155 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
156 {
157 	int res = 0;
158 	struct inode *inode = filp->f_dentry->d_inode;
159 
160 	dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
161 
162 	/* No mandatory locks */
163 	if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
164 		return -ENOLCK;
165 
166 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
167 		filemap_write_and_wait(inode->i_mapping);
168 		invalidate_inode_pages(&inode->i_data);
169 	}
170 
171 	return res;
172 }
173 
174 /**
175  * v9fs_file_read - read from a file
176  * @filep: file pointer to read
177  * @data: data buffer to read data into
178  * @count: size of buffer
179  * @offset: offset at which to read data
180  *
181  */
182 static ssize_t
183 v9fs_file_read(struct file *filp, char __user * data, size_t count,
184 	       loff_t * offset)
185 {
186 	struct inode *inode = filp->f_dentry->d_inode;
187 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
188 	struct v9fs_fid *v9f = filp->private_data;
189 	struct v9fs_fcall *fcall = NULL;
190 	int fid = v9f->fid;
191 	int rsize = 0;
192 	int result = 0;
193 	int total = 0;
194 	int n;
195 
196 	dprintk(DEBUG_VFS, "\n");
197 
198 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
199 	if (v9f->iounit != 0 && rsize > v9f->iounit)
200 		rsize = v9f->iounit;
201 
202 	do {
203 		if (count < rsize)
204 			rsize = count;
205 
206 		result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
207 
208 		if (result < 0) {
209 			printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
210 			       result);
211 
212 			kfree(fcall);
213 			return total;
214 		} else
215 			*offset += result;
216 
217 		n = copy_to_user(data, fcall->params.rread.data, result);
218 		if (n) {
219 			dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
220 			kfree(fcall);
221 			return -EFAULT;
222 		}
223 
224 		count -= result;
225 		data += result;
226 		total += result;
227 
228 		kfree(fcall);
229 
230 		if (result < rsize)
231 			break;
232 	} while (count);
233 
234 	return total;
235 }
236 
237 /**
238  * v9fs_file_write - write to a file
239  * @filep: file pointer to write
240  * @data: data buffer to write data from
241  * @count: size of buffer
242  * @offset: offset at which to write data
243  *
244  */
245 
246 static ssize_t
247 v9fs_file_write(struct file *filp, const char __user * data,
248 		size_t count, loff_t * offset)
249 {
250 	struct inode *inode = filp->f_dentry->d_inode;
251 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
252 	struct v9fs_fid *v9fid = filp->private_data;
253 	struct v9fs_fcall *fcall;
254 	int fid = v9fid->fid;
255 	int result = -EIO;
256 	int rsize = 0;
257 	int total = 0;
258 
259 	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
260 		(int)*offset);
261 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
262 	if (v9fid->iounit != 0 && rsize > v9fid->iounit)
263 		rsize = v9fid->iounit;
264 
265 	do {
266 		if (count < rsize)
267 			rsize = count;
268 
269 		result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
270 		if (result < 0) {
271 			PRINT_FCALL_ERROR("error while writing", fcall);
272 			kfree(fcall);
273 			return result;
274 		} else
275 			*offset += result;
276 
277 		kfree(fcall);
278 		fcall = NULL;
279 
280 		if (result != rsize) {
281 			eprintk(KERN_ERR,
282 				"short write: v9fs_t_write returned %d\n",
283 				result);
284 			break;
285 		}
286 
287 		count -= result;
288 		data += result;
289 		total += result;
290 	} while (count);
291 
292 	return total;
293 }
294 
295 struct file_operations v9fs_file_operations = {
296 	.llseek = generic_file_llseek,
297 	.read = v9fs_file_read,
298 	.write = v9fs_file_write,
299 	.open = v9fs_file_open,
300 	.release = v9fs_dir_release,
301 	.lock = v9fs_file_lock,
302 };
303