xref: /linux/fs/coda/file.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 */
31 static int use_coda_close;
32 
33 static ssize_t
34 coda_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 
49 static ssize_t
50 coda_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 
66 static ssize_t
67 coda_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_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_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 
94 static int
95 coda_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_dentry->d_inode;
110 	host_inode = host_file->f_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 
128 int 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 		unlock_kernel();
141 		return -ENOMEM;
142 	}
143 
144 	lock_kernel();
145 
146 	error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
147 			   &host_file);
148 	if (error || !host_file) {
149 		kfree(cfi);
150 		unlock_kernel();
151 		return error;
152 	}
153 
154 	host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
155 
156 	cfi->cfi_magic = CODA_MAGIC;
157 	cfi->cfi_mapcount = 0;
158 	cfi->cfi_container = host_file;
159 
160 	BUG_ON(coda_file->private_data != NULL);
161 	coda_file->private_data = cfi;
162 
163 	unlock_kernel();
164 	return 0;
165 }
166 
167 int coda_flush(struct file *coda_file)
168 {
169 	unsigned short flags = coda_file->f_flags & ~O_EXCL;
170 	unsigned short coda_flags = coda_flags_to_cflags(flags);
171 	struct coda_file_info *cfi;
172 	struct inode *coda_inode;
173 	int err = 0, fcnt;
174 
175 	lock_kernel();
176 
177 	coda_vfs_stat.flush++;
178 
179 	/* last close semantics */
180 	fcnt = file_count(coda_file);
181 	if (fcnt > 1)
182 		goto out;
183 
184 	/* No need to make an upcall when we have not made any modifications
185 	 * to the file */
186 	if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY)
187 		goto out;
188 
189 	if (use_coda_close)
190 		goto out;
191 
192 	cfi = CODA_FTOC(coda_file);
193 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
194 
195 	coda_inode = coda_file->f_dentry->d_inode;
196 
197 	err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
198 			  coda_file->f_uid);
199 
200 	if (err == -EOPNOTSUPP) {
201 		use_coda_close = 1;
202 		err = 0;
203 	}
204 
205 out:
206 	unlock_kernel();
207 	return err;
208 }
209 
210 int coda_release(struct inode *coda_inode, struct file *coda_file)
211 {
212 	unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
213 	unsigned short coda_flags = coda_flags_to_cflags(flags);
214 	struct coda_file_info *cfi;
215 	struct coda_inode_info *cii;
216 	struct inode *host_inode;
217 	int err = 0;
218 
219 	lock_kernel();
220 	coda_vfs_stat.release++;
221 
222 	if (!use_coda_close) {
223 		err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode),
224 				    coda_flags);
225 		if (err == -EOPNOTSUPP) {
226 			use_coda_close = 1;
227 			err = 0;
228 		}
229 	}
230 
231 	cfi = CODA_FTOC(coda_file);
232 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
233 
234 	if (use_coda_close)
235 		err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
236 				  coda_flags, coda_file->f_uid);
237 
238 	host_inode = cfi->cfi_container->f_dentry->d_inode;
239 	cii = ITOC(coda_inode);
240 
241 	/* did we mmap this file? */
242 	if (coda_inode->i_mapping == &host_inode->i_data) {
243 		cii->c_mapcount -= cfi->cfi_mapcount;
244 		if (!cii->c_mapcount)
245 			coda_inode->i_mapping = &coda_inode->i_data;
246 	}
247 
248 	fput(cfi->cfi_container);
249 	kfree(coda_file->private_data);
250 	coda_file->private_data = NULL;
251 
252 	unlock_kernel();
253 	return err;
254 }
255 
256 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
257 {
258 	struct file *host_file;
259 	struct dentry *host_dentry;
260 	struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
261 	struct coda_file_info *cfi;
262 	int err = 0;
263 
264 	if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
265 	      S_ISLNK(coda_inode->i_mode)))
266 		return -EINVAL;
267 
268 	cfi = CODA_FTOC(coda_file);
269 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
270 	host_file = cfi->cfi_container;
271 
272 	coda_vfs_stat.fsync++;
273 
274 	if (host_file->f_op && host_file->f_op->fsync) {
275 		host_dentry = host_file->f_dentry;
276 		host_inode = host_dentry->d_inode;
277 		mutex_lock(&host_inode->i_mutex);
278 		err = host_file->f_op->fsync(host_file, host_dentry, datasync);
279 		mutex_unlock(&host_inode->i_mutex);
280 	}
281 
282 	if ( !err && !datasync ) {
283 		lock_kernel();
284 		err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
285 		unlock_kernel();
286 	}
287 
288 	return err;
289 }
290 
291 const struct file_operations coda_file_operations = {
292 	.llseek		= generic_file_llseek,
293 	.read		= coda_file_read,
294 	.write		= coda_file_write,
295 	.mmap		= coda_file_mmap,
296 	.open		= coda_open,
297 	.flush		= coda_flush,
298 	.release	= coda_release,
299 	.fsync		= coda_fsync,
300 	.sendfile	= coda_file_sendfile,
301 };
302 
303