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 <linux/pagemap.h>
36#include <asm/uaccess.h>
37#include <linux/idr.h>
38#include <net/9p/9p.h>
39#include <net/9p/client.h>
40
41#include "v9fs.h"
42#include "v9fs_vfs.h"
43#include "fid.h"
44#include "cache.h"
45
46static const struct file_operations v9fs_cached_file_operations;
47
48/**
49 * v9fs_file_open - open a file (or directory)
50 * @inode: inode to be opened
51 * @file: file being opened
52 *
53 */
54
55int v9fs_file_open(struct inode *inode, struct file *file)
56{
57	int err;
58	struct v9fs_session_info *v9ses;
59	struct p9_fid *fid;
60	int omode;
61
62	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
63	v9ses = v9fs_inode2v9ses(inode);
64	if (v9fs_proto_dotl(v9ses))
65		omode = file->f_flags;
66	else
67		omode = v9fs_uflags2omode(file->f_flags,
68					v9fs_proto_dotu(v9ses));
69	fid = file->private_data;
70	if (!fid) {
71		fid = v9fs_fid_clone(file->f_path.dentry);
72		if (IS_ERR(fid))
73			return PTR_ERR(fid);
74
75		err = p9_client_open(fid, omode);
76		if (err < 0) {
77			p9_client_clunk(fid);
78			return err;
79		}
80		if (file->f_flags & O_TRUNC) {
81			i_size_write(inode, 0);
82			inode->i_blocks = 0;
83		}
84		if ((file->f_flags & O_APPEND) &&
85			(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
86			generic_file_llseek(file, 0, SEEK_END);
87	}
88
89	file->private_data = fid;
90	if ((fid->qid.version) && (v9ses->cache)) {
91		P9_DPRINTK(P9_DEBUG_VFS, "cached");
92		/* enable cached file options */
93		if(file->f_op == &v9fs_file_operations)
94			file->f_op = &v9fs_cached_file_operations;
95
96#ifdef CONFIG_9P_FSCACHE
97		v9fs_cache_inode_set_cookie(inode, file);
98#endif
99	}
100
101	return 0;
102}
103
104/**
105 * v9fs_file_lock - lock a file (or directory)
106 * @filp: file to be locked
107 * @cmd: lock command
108 * @fl: file lock structure
109 *
110 * Bugs: this looks like a local only lock, we should extend into 9P
111 *       by using open exclusive
112 */
113
114static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
115{
116	int res = 0;
117	struct inode *inode = filp->f_path.dentry->d_inode;
118
119	P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
120
121	/* No mandatory locks */
122	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
123		return -ENOLCK;
124
125	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
126		filemap_write_and_wait(inode->i_mapping);
127		invalidate_mapping_pages(&inode->i_data, 0, -1);
128	}
129
130	return res;
131}
132
133/**
134 * v9fs_file_readn - read from a file
135 * @filp: file pointer to read
136 * @data: data buffer to read data into
137 * @udata: user data buffer to read data into
138 * @count: size of buffer
139 * @offset: offset at which to read data
140 *
141 */
142
143ssize_t
144v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
145	       u64 offset)
146{
147	int n, total, size;
148	struct p9_fid *fid = filp->private_data;
149
150	P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
151					(long long unsigned) offset, count);
152
153	n = 0;
154	total = 0;
155	size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
156	do {
157		n = p9_client_read(fid, data, udata, offset, count);
158		if (n <= 0)
159			break;
160
161		if (data)
162			data += n;
163		if (udata)
164			udata += n;
165
166		offset += n;
167		count -= n;
168		total += n;
169	} while (count > 0 && n == size);
170
171	if (n < 0)
172		total = n;
173
174	return total;
175}
176
177/**
178 * v9fs_file_read - read from a file
179 * @filp: file pointer to read
180 * @udata: user data buffer to read data into
181 * @count: size of buffer
182 * @offset: offset at which to read data
183 *
184 */
185
186static ssize_t
187v9fs_file_read(struct file *filp, char __user *udata, size_t count,
188	       loff_t * offset)
189{
190	int ret;
191	struct p9_fid *fid;
192	size_t size;
193
194	P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
195	fid = filp->private_data;
196
197	size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
198	if (count > size)
199		ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
200	else
201		ret = p9_client_read(fid, NULL, udata, *offset, count);
202
203	if (ret > 0)
204		*offset += ret;
205
206	return ret;
207}
208
209/**
210 * v9fs_file_write - write to a file
211 * @filp: file pointer to write
212 * @data: data buffer to write data from
213 * @count: size of buffer
214 * @offset: offset at which to write data
215 *
216 */
217
218static ssize_t
219v9fs_file_write(struct file *filp, const char __user * data,
220		size_t count, loff_t * offset)
221{
222	int n, rsize, total = 0;
223	struct p9_fid *fid;
224	struct p9_client *clnt;
225	struct inode *inode = filp->f_path.dentry->d_inode;
226	loff_t origin = *offset;
227	unsigned long pg_start, pg_end;
228
229	P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
230		(int)count, (int)*offset);
231
232	fid = filp->private_data;
233	clnt = fid->clnt;
234
235	rsize = fid->iounit ? fid->iounit : clnt->msize - P9_IOHDRSZ;
236
237	do {
238		if (count < rsize)
239			rsize = count;
240
241		n = p9_client_write(fid, NULL, data+total, origin+total,
242									rsize);
243		if (n <= 0)
244			break;
245		count -= n;
246		total += n;
247	} while (count > 0);
248
249	if (total > 0) {
250		pg_start = origin >> PAGE_CACHE_SHIFT;
251		pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
252		if (inode->i_mapping && inode->i_mapping->nrpages)
253			invalidate_inode_pages2_range(inode->i_mapping,
254						      pg_start, pg_end);
255		*offset += total;
256		i_size_write(inode, i_size_read(inode) + total);
257		inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
258	}
259
260	if (n < 0)
261		return n;
262
263	return total;
264}
265
266static int v9fs_file_fsync(struct file *filp, int datasync)
267{
268	struct p9_fid *fid;
269	struct p9_wstat wstat;
270	int retval;
271
272	P9_DPRINTK(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
273
274	fid = filp->private_data;
275	v9fs_blank_wstat(&wstat);
276
277	retval = p9_client_wstat(fid, &wstat);
278	return retval;
279}
280
281static const struct file_operations v9fs_cached_file_operations = {
282	.llseek = generic_file_llseek,
283	.read = do_sync_read,
284	.aio_read = generic_file_aio_read,
285	.write = v9fs_file_write,
286	.open = v9fs_file_open,
287	.release = v9fs_dir_release,
288	.lock = v9fs_file_lock,
289	.mmap = generic_file_readonly_mmap,
290	.fsync = v9fs_file_fsync,
291};
292
293const struct file_operations v9fs_file_operations = {
294	.llseek = generic_file_llseek,
295	.read = v9fs_file_read,
296	.write = v9fs_file_write,
297	.open = v9fs_file_open,
298	.release = v9fs_dir_release,
299	.lock = v9fs_file_lock,
300	.mmap = generic_file_readonly_mmap,
301	.fsync = v9fs_file_fsync,
302};
303
304const struct file_operations v9fs_file_operations_dotl = {
305	.llseek = generic_file_llseek,
306	.read = v9fs_file_read,
307	.write = v9fs_file_write,
308	.open = v9fs_file_open,
309	.release = v9fs_dir_release,
310	.lock = v9fs_file_lock,
311	.mmap = generic_file_readonly_mmap,
312	.fsync = v9fs_file_fsync,
313};
314