xref: /openbmc/linux/fs/9p/vfs_file.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 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/sched.h>
30 #include <linux/file.h>
31 #include <linux/stat.h>
32 #include <linux/string.h>
33 #include <linux/inet.h>
34 #include <linux/list.h>
35 #include <asm/uaccess.h>
36 #include <linux/idr.h>
37 
38 #include "debug.h"
39 #include "v9fs.h"
40 #include "9p.h"
41 #include "v9fs_vfs.h"
42 #include "fid.h"
43 
44 static const struct file_operations v9fs_cached_file_operations;
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 *vfid;
57 	struct v9fs_fcall *fcall = NULL;
58 	int omode;
59 	int err;
60 
61 	dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
62 
63 	vfid = v9fs_fid_clone(file->f_path.dentry);
64 	if (IS_ERR(vfid))
65 		return PTR_ERR(vfid);
66 
67 	omode = v9fs_uflags2omode(file->f_flags);
68 	err = v9fs_t_open(v9ses, vfid->fid, omode, &fcall);
69 	if (err < 0) {
70 		PRINT_FCALL_ERROR("open failed", fcall);
71 		goto Clunk_Fid;
72 	}
73 
74 	file->private_data = vfid;
75 	vfid->fidopen = 1;
76 	vfid->fidclunked = 0;
77 	vfid->iounit = fcall->params.ropen.iounit;
78 	vfid->rdir_pos = 0;
79 	vfid->rdir_fcall = NULL;
80 	vfid->filp = file;
81 	kfree(fcall);
82 
83 	if((vfid->qid.version) && (v9ses->cache)) {
84 		dprintk(DEBUG_VFS, "cached");
85 		/* enable cached file options */
86 		if(file->f_op == &v9fs_file_operations)
87 			file->f_op = &v9fs_cached_file_operations;
88 	}
89 
90 	return 0;
91 
92 Clunk_Fid:
93 	v9fs_fid_clunk(v9ses, vfid);
94 	kfree(fcall);
95 
96 	return err;
97 }
98 
99 /**
100  * v9fs_file_lock - lock a file (or directory)
101  * @inode: inode to be opened
102  * @file: file being opened
103  *
104  * XXX - this looks like a local only lock, we should extend into 9P
105  *       by using open exclusive
106  */
107 
108 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
109 {
110 	int res = 0;
111 	struct inode *inode = filp->f_path.dentry->d_inode;
112 
113 	dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
114 
115 	/* No mandatory locks */
116 	if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
117 		return -ENOLCK;
118 
119 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
120 		filemap_write_and_wait(inode->i_mapping);
121 		invalidate_mapping_pages(&inode->i_data, 0, -1);
122 	}
123 
124 	return res;
125 }
126 
127 /**
128  * v9fs_file_read - read from a file
129  * @filep: file pointer to read
130  * @data: data buffer to read data into
131  * @count: size of buffer
132  * @offset: offset at which to read data
133  *
134  */
135 static ssize_t
136 v9fs_file_read(struct file *filp, char __user * data, size_t count,
137 	       loff_t * offset)
138 {
139 	struct inode *inode = filp->f_path.dentry->d_inode;
140 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
141 	struct v9fs_fid *v9f = filp->private_data;
142 	struct v9fs_fcall *fcall = NULL;
143 	int fid = v9f->fid;
144 	int rsize = 0;
145 	int result = 0;
146 	int total = 0;
147 	int n;
148 
149 	dprintk(DEBUG_VFS, "\n");
150 
151 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
152 	if (v9f->iounit != 0 && rsize > v9f->iounit)
153 		rsize = v9f->iounit;
154 
155 	do {
156 		if (count < rsize)
157 			rsize = count;
158 
159 		result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
160 
161 		if (result < 0) {
162 			printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
163 			       result);
164 
165 			kfree(fcall);
166 			return total;
167 		} else
168 			*offset += result;
169 
170 		n = copy_to_user(data, fcall->params.rread.data, result);
171 		if (n) {
172 			dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
173 			kfree(fcall);
174 			return -EFAULT;
175 		}
176 
177 		count -= result;
178 		data += result;
179 		total += result;
180 
181 		kfree(fcall);
182 
183 		if (result < rsize)
184 			break;
185 	} while (count);
186 
187 	return total;
188 }
189 
190 /**
191  * v9fs_file_write - write to a file
192  * @filep: file pointer to write
193  * @data: data buffer to write data from
194  * @count: size of buffer
195  * @offset: offset at which to write data
196  *
197  */
198 
199 static ssize_t
200 v9fs_file_write(struct file *filp, const char __user * data,
201 		size_t count, loff_t * offset)
202 {
203 	struct inode *inode = filp->f_path.dentry->d_inode;
204 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
205 	struct v9fs_fid *v9fid = filp->private_data;
206 	struct v9fs_fcall *fcall;
207 	int fid = v9fid->fid;
208 	int result = -EIO;
209 	int rsize = 0;
210 	int total = 0;
211 
212 	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
213 		(int)*offset);
214 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
215 	if (v9fid->iounit != 0 && rsize > v9fid->iounit)
216 		rsize = v9fid->iounit;
217 
218 	do {
219 		if (count < rsize)
220 			rsize = count;
221 
222 		result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
223 		if (result < 0) {
224 			PRINT_FCALL_ERROR("error while writing", fcall);
225 			kfree(fcall);
226 			return result;
227 		} else
228 			*offset += result;
229 
230 		kfree(fcall);
231 		fcall = NULL;
232 
233 		if (result != rsize) {
234 			eprintk(KERN_ERR,
235 				"short write: v9fs_t_write returned %d\n",
236 				result);
237 			break;
238 		}
239 
240 		count -= result;
241 		data += result;
242 		total += result;
243 	} while (count);
244 
245 	invalidate_inode_pages2(inode->i_mapping);
246 	return total;
247 }
248 
249 static const struct file_operations v9fs_cached_file_operations = {
250 	.llseek = generic_file_llseek,
251 	.read = do_sync_read,
252 	.aio_read = generic_file_aio_read,
253 	.write = v9fs_file_write,
254 	.open = v9fs_file_open,
255 	.release = v9fs_dir_release,
256 	.lock = v9fs_file_lock,
257 	.mmap = generic_file_mmap,
258 };
259 
260 const struct file_operations v9fs_file_operations = {
261 	.llseek = generic_file_llseek,
262 	.read = v9fs_file_read,
263 	.write = v9fs_file_write,
264 	.open = v9fs_file_open,
265 	.release = v9fs_dir_release,
266 	.lock = v9fs_file_lock,
267 	.mmap = generic_file_mmap,
268 };
269