xref: /linux/fs/9p/vfs_file.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15) 
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/file.h>
30 #include <linux/stat.h>
31 #include <linux/string.h>
32 #include <linux/smp_lock.h>
33 #include <linux/inet.h>
34 #include <linux/version.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 *vfid;
56 	struct v9fs_fcall *fcall = NULL;
57 	int omode;
58 	int fid = V9FS_NOFID;
59 	int err;
60 
61 	dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
62 
63 	vfid = v9fs_fid_lookup(file->f_dentry);
64 	if (!vfid) {
65 		dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
66 		return -EBADF;
67 	}
68 
69 	fid = v9fs_get_idpool(&v9ses->fidpool);
70 	if (fid < 0) {
71 		eprintk(KERN_WARNING, "newfid fails!\n");
72 		return -ENOSPC;
73 	}
74 
75 	err = v9fs_t_walk(v9ses, vfid->fid, fid, NULL, &fcall);
76 	if (err < 0) {
77 		dprintk(DEBUG_ERROR, "rewalk didn't work\n");
78 		if (fcall && fcall->id == RWALK)
79 			goto clunk_fid;
80 		else {
81 			v9fs_put_idpool(fid, &v9ses->fidpool);
82 			goto free_fcall;
83 		}
84 	}
85 	kfree(fcall);
86 
87 	/* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
88 	/* translate open mode appropriately */
89 	omode = v9fs_uflags2omode(file->f_flags);
90 	err = v9fs_t_open(v9ses, fid, omode, &fcall);
91 	if (err < 0) {
92 		PRINT_FCALL_ERROR("open failed", fcall);
93 		goto clunk_fid;
94 	}
95 
96 	vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
97 	if (vfid == NULL) {
98 		dprintk(DEBUG_ERROR, "out of memory\n");
99 		err = -ENOMEM;
100 		goto clunk_fid;
101 	}
102 
103 	file->private_data = vfid;
104 	vfid->fid = fid;
105 	vfid->fidopen = 1;
106 	vfid->fidclunked = 0;
107 	vfid->iounit = fcall->params.ropen.iounit;
108 	vfid->rdir_pos = 0;
109 	vfid->rdir_fcall = NULL;
110 	vfid->filp = file;
111 	kfree(fcall);
112 
113 	return 0;
114 
115 clunk_fid:
116 	v9fs_t_clunk(v9ses, fid);
117 
118 free_fcall:
119 	kfree(fcall);
120 
121 	return err;
122 }
123 
124 /**
125  * v9fs_file_lock - lock a file (or directory)
126  * @inode: inode to be opened
127  * @file: file being opened
128  *
129  * XXX - this looks like a local only lock, we should extend into 9P
130  *       by using open exclusive
131  */
132 
133 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
134 {
135 	int res = 0;
136 	struct inode *inode = filp->f_dentry->d_inode;
137 
138 	dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
139 
140 	/* No mandatory locks */
141 	if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
142 		return -ENOLCK;
143 
144 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
145 		filemap_write_and_wait(inode->i_mapping);
146 		invalidate_inode_pages(&inode->i_data);
147 	}
148 
149 	return res;
150 }
151 
152 /**
153  * v9fs_file_read - read from a file
154  * @filep: file pointer to read
155  * @data: data buffer to read data into
156  * @count: size of buffer
157  * @offset: offset at which to read data
158  *
159  */
160 static ssize_t
161 v9fs_file_read(struct file *filp, char __user * data, size_t count,
162 	       loff_t * offset)
163 {
164 	struct inode *inode = filp->f_dentry->d_inode;
165 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
166 	struct v9fs_fid *v9f = filp->private_data;
167 	struct v9fs_fcall *fcall = NULL;
168 	int fid = v9f->fid;
169 	int rsize = 0;
170 	int result = 0;
171 	int total = 0;
172 	int n;
173 
174 	dprintk(DEBUG_VFS, "\n");
175 
176 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
177 	if (v9f->iounit != 0 && rsize > v9f->iounit)
178 		rsize = v9f->iounit;
179 
180 	do {
181 		if (count < rsize)
182 			rsize = count;
183 
184 		result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
185 
186 		if (result < 0) {
187 			printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
188 			       result);
189 
190 			kfree(fcall);
191 			return total;
192 		} else
193 			*offset += result;
194 
195 		n = copy_to_user(data, fcall->params.rread.data, result);
196 		if (n) {
197 			dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
198 			kfree(fcall);
199 			return -EFAULT;
200 		}
201 
202 		count -= result;
203 		data += result;
204 		total += result;
205 
206 		kfree(fcall);
207 
208 		if (result < rsize)
209 			break;
210 	} while (count);
211 
212 	return total;
213 }
214 
215 /**
216  * v9fs_file_write - write to a file
217  * @filep: file pointer to write
218  * @data: data buffer to write data from
219  * @count: size of buffer
220  * @offset: offset at which to write data
221  *
222  */
223 
224 static ssize_t
225 v9fs_file_write(struct file *filp, const char __user * data,
226 		size_t count, loff_t * offset)
227 {
228 	struct inode *inode = filp->f_dentry->d_inode;
229 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
230 	struct v9fs_fid *v9fid = filp->private_data;
231 	struct v9fs_fcall *fcall;
232 	int fid = v9fid->fid;
233 	int result = -EIO;
234 	int rsize = 0;
235 	int total = 0;
236 
237 	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
238 		(int)*offset);
239 	rsize = v9ses->maxdata - V9FS_IOHDRSZ;
240 	if (v9fid->iounit != 0 && rsize > v9fid->iounit)
241 		rsize = v9fid->iounit;
242 
243 	do {
244 		if (count < rsize)
245 			rsize = count;
246 
247 		result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
248 		if (result < 0) {
249 			PRINT_FCALL_ERROR("error while writing", fcall);
250 			kfree(fcall);
251 			return result;
252 		} else
253 			*offset += result;
254 
255 		kfree(fcall);
256 		fcall = NULL;
257 
258 		if (result != rsize) {
259 			eprintk(KERN_ERR,
260 				"short write: v9fs_t_write returned %d\n",
261 				result);
262 			break;
263 		}
264 
265 		count -= result;
266 		data += result;
267 		total += result;
268 	} while (count);
269 
270 		invalidate_inode_pages2(inode->i_mapping);
271 	return total;
272 }
273 
274 const struct file_operations v9fs_file_operations = {
275 	.llseek = generic_file_llseek,
276 	.read = v9fs_file_read,
277 	.write = v9fs_file_write,
278 	.open = v9fs_file_open,
279 	.release = v9fs_dir_release,
280 	.lock = v9fs_file_lock,
281 	.mmap = generic_file_mmap,
282 };
283