1/*
2 * File operations for Coda.
3 * Original version: (C) 1996 Peter Braam
4 * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
5 *
6 * Carnegie Mellon encourages users of this code to contribute improvements
7 * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
8 */
9
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/time.h>
13#include <linux/file.h>
14#include <linux/fs.h>
15#include <linux/stat.h>
16#include <linux/errno.h>
17#include <linux/smp_lock.h>
18#include <linux/string.h>
19#include <asm/uaccess.h>
20
21#include <linux/coda.h>
22#include <linux/coda_linux.h>
23#include <linux/coda_fs_i.h>
24#include <linux/coda_psdev.h>
25#include <linux/coda_proc.h>
26
27#include "coda_int.h"
28
29/* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support
30 * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */
31static int use_coda_close;
32
33static ssize_t
34coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
35{
36	struct coda_file_info *cfi;
37	struct file *host_file;
38
39	cfi = CODA_FTOC(coda_file);
40	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
41	host_file = cfi->cfi_container;
42
43	if (!host_file->f_op || !host_file->f_op->read)
44		return -EINVAL;
45
46	return host_file->f_op->read(host_file, buf, count, ppos);
47}
48
49static ssize_t
50coda_file_sendfile(struct file *coda_file, loff_t *ppos, size_t count,
51		   read_actor_t actor, void *target)
52{
53	struct coda_file_info *cfi;
54	struct file *host_file;
55
56	cfi = CODA_FTOC(coda_file);
57	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
58	host_file = cfi->cfi_container;
59
60	if (!host_file->f_op || !host_file->f_op->sendfile)
61		return -EINVAL;
62
63	return host_file->f_op->sendfile(host_file, ppos, count, actor, target);
64}
65
66static ssize_t
67coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
68{
69	struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
70	struct coda_file_info *cfi;
71	struct file *host_file;
72	ssize_t ret;
73
74	cfi = CODA_FTOC(coda_file);
75	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
76	host_file = cfi->cfi_container;
77
78	if (!host_file->f_op || !host_file->f_op->write)
79		return -EINVAL;
80
81	host_inode = host_file->f_path.dentry->d_inode;
82	mutex_lock(&coda_inode->i_mutex);
83
84	ret = host_file->f_op->write(host_file, buf, count, ppos);
85
86	coda_inode->i_size = host_inode->i_size;
87	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
88	coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
89	mutex_unlock(&coda_inode->i_mutex);
90
91	return ret;
92}
93
94static int
95coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
96{
97	struct coda_file_info *cfi;
98	struct coda_inode_info *cii;
99	struct file *host_file;
100	struct inode *coda_inode, *host_inode;
101
102	cfi = CODA_FTOC(coda_file);
103	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
104	host_file = cfi->cfi_container;
105
106	if (!host_file->f_op || !host_file->f_op->mmap)
107		return -ENODEV;
108
109	coda_inode = coda_file->f_path.dentry->d_inode;
110	host_inode = host_file->f_path.dentry->d_inode;
111	coda_file->f_mapping = host_file->f_mapping;
112	if (coda_inode->i_mapping == &coda_inode->i_data)
113		coda_inode->i_mapping = host_inode->i_mapping;
114
115	/* only allow additional mmaps as long as userspace isn't changing
116	 * the container file on us! */
117	else if (coda_inode->i_mapping != host_inode->i_mapping)
118		return -EBUSY;
119
120	/* keep track of how often the coda_inode/host_file has been mmapped */
121	cii = ITOC(coda_inode);
122	cii->c_mapcount++;
123	cfi->cfi_mapcount++;
124
125	return host_file->f_op->mmap(host_file, vma);
126}
127
128int coda_open(struct inode *coda_inode, struct file *coda_file)
129{
130	struct file *host_file = NULL;
131	int error;
132	unsigned short flags = coda_file->f_flags & (~O_EXCL);
133	unsigned short coda_flags = coda_flags_to_cflags(flags);
134	struct coda_file_info *cfi;
135
136	coda_vfs_stat.open++;
137
138	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
139	if (!cfi)
140		return -ENOMEM;
141
142	lock_kernel();
143
144	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
145			   &host_file);
146	if (error || !host_file) {
147		kfree(cfi);
148		unlock_kernel();
149		return error;
150	}
151
152	host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
153
154	cfi->cfi_magic = CODA_MAGIC;
155	cfi->cfi_mapcount = 0;
156	cfi->cfi_container = host_file;
157
158	BUG_ON(coda_file->private_data != NULL);
159	coda_file->private_data = cfi;
160
161	unlock_kernel();
162	return 0;
163}
164
165int coda_flush(struct file *coda_file, fl_owner_t id)
166{
167	unsigned short flags = coda_file->f_flags & ~O_EXCL;
168	unsigned short coda_flags = coda_flags_to_cflags(flags);
169	struct coda_file_info *cfi;
170	struct inode *coda_inode;
171	int err = 0, fcnt;
172
173	lock_kernel();
174
175	coda_vfs_stat.flush++;
176
177	/* last close semantics */
178	fcnt = file_count(coda_file);
179	if (fcnt > 1)
180		goto out;
181
182	/* No need to make an upcall when we have not made any modifications
183	 * to the file */
184	if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY)
185		goto out;
186
187	if (use_coda_close)
188		goto out;
189
190	cfi = CODA_FTOC(coda_file);
191	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
192
193	coda_inode = coda_file->f_path.dentry->d_inode;
194
195	err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
196			  coda_file->f_uid);
197
198	if (err == -EOPNOTSUPP) {
199		use_coda_close = 1;
200		err = 0;
201	}
202
203out:
204	unlock_kernel();
205	return err;
206}
207
208int coda_release(struct inode *coda_inode, struct file *coda_file)
209{
210	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
211	unsigned short coda_flags = coda_flags_to_cflags(flags);
212	struct coda_file_info *cfi;
213	struct coda_inode_info *cii;
214	struct inode *host_inode;
215	int err = 0;
216
217	lock_kernel();
218	coda_vfs_stat.release++;
219
220	if (!use_coda_close) {
221		err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode),
222				    coda_flags);
223		if (err == -EOPNOTSUPP) {
224			use_coda_close = 1;
225			err = 0;
226		}
227	}
228
229	cfi = CODA_FTOC(coda_file);
230	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
231
232	if (use_coda_close)
233		err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
234				  coda_flags, coda_file->f_uid);
235
236	host_inode = cfi->cfi_container->f_path.dentry->d_inode;
237	cii = ITOC(coda_inode);
238
239	/* did we mmap this file? */
240	if (coda_inode->i_mapping == &host_inode->i_data) {
241		cii->c_mapcount -= cfi->cfi_mapcount;
242		if (!cii->c_mapcount)
243			coda_inode->i_mapping = &coda_inode->i_data;
244	}
245
246	fput(cfi->cfi_container);
247	kfree(coda_file->private_data);
248	coda_file->private_data = NULL;
249
250	unlock_kernel();
251	return err;
252}
253
254int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
255{
256	struct file *host_file;
257	struct dentry *host_dentry;
258	struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
259	struct coda_file_info *cfi;
260	int err = 0;
261
262	if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
263	      S_ISLNK(coda_inode->i_mode)))
264		return -EINVAL;
265
266	cfi = CODA_FTOC(coda_file);
267	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
268	host_file = cfi->cfi_container;
269
270	coda_vfs_stat.fsync++;
271
272	if (host_file->f_op && host_file->f_op->fsync) {
273		host_dentry = host_file->f_path.dentry;
274		host_inode = host_dentry->d_inode;
275		mutex_lock(&host_inode->i_mutex);
276		err = host_file->f_op->fsync(host_file, host_dentry, datasync);
277		mutex_unlock(&host_inode->i_mutex);
278	}
279
280	if ( !err && !datasync ) {
281		lock_kernel();
282		err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
283		unlock_kernel();
284	}
285
286	return err;
287}
288
289const struct file_operations coda_file_operations = {
290	.llseek		= generic_file_llseek,
291	.read		= coda_file_read,
292	.write		= coda_file_write,
293	.mmap		= coda_file_mmap,
294	.open		= coda_open,
295	.flush		= coda_flush,
296	.release	= coda_release,
297	.fsync		= coda_fsync,
298	.sendfile	= coda_file_sendfile,
299};
300