xref: /openbmc/linux/fs/coda/file.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 /* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support
28  * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */
29 static int use_coda_close;
30 
31 static ssize_t
32 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
33 {
34 	struct coda_file_info *cfi;
35 	struct file *host_file;
36 
37 	cfi = CODA_FTOC(coda_file);
38 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
39 	host_file = cfi->cfi_container;
40 
41 	if (!host_file->f_op || !host_file->f_op->read)
42 		return -EINVAL;
43 
44 	return host_file->f_op->read(host_file, buf, count, ppos);
45 }
46 
47 static ssize_t
48 coda_file_sendfile(struct file *coda_file, loff_t *ppos, size_t count,
49 		   read_actor_t actor, void *target)
50 {
51 	struct coda_file_info *cfi;
52 	struct file *host_file;
53 
54 	cfi = CODA_FTOC(coda_file);
55 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
56 	host_file = cfi->cfi_container;
57 
58 	if (!host_file->f_op || !host_file->f_op->sendfile)
59 		return -EINVAL;
60 
61 	return host_file->f_op->sendfile(host_file, ppos, count, actor, target);
62 }
63 
64 static ssize_t
65 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
66 {
67 	struct inode *host_inode, *coda_inode = coda_file->f_dentry->d_inode;
68 	struct coda_file_info *cfi;
69 	struct file *host_file;
70 	ssize_t ret;
71 
72 	cfi = CODA_FTOC(coda_file);
73 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
74 	host_file = cfi->cfi_container;
75 
76 	if (!host_file->f_op || !host_file->f_op->write)
77 		return -EINVAL;
78 
79 	host_inode = host_file->f_dentry->d_inode;
80 	down(&coda_inode->i_sem);
81 
82 	ret = host_file->f_op->write(host_file, buf, count, ppos);
83 
84 	coda_inode->i_size = host_inode->i_size;
85 	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
86 	coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
87 	up(&coda_inode->i_sem);
88 
89 	return ret;
90 }
91 
92 static int
93 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
94 {
95 	struct coda_file_info *cfi;
96 	struct coda_inode_info *cii;
97 	struct file *host_file;
98 	struct inode *coda_inode, *host_inode;
99 
100 	cfi = CODA_FTOC(coda_file);
101 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
102 	host_file = cfi->cfi_container;
103 
104 	if (!host_file->f_op || !host_file->f_op->mmap)
105 		return -ENODEV;
106 
107 	coda_inode = coda_file->f_dentry->d_inode;
108 	host_inode = host_file->f_dentry->d_inode;
109 	coda_file->f_mapping = host_file->f_mapping;
110 	if (coda_inode->i_mapping == &coda_inode->i_data)
111 		coda_inode->i_mapping = host_inode->i_mapping;
112 
113 	/* only allow additional mmaps as long as userspace isn't changing
114 	 * the container file on us! */
115 	else if (coda_inode->i_mapping != host_inode->i_mapping)
116 		return -EBUSY;
117 
118 	/* keep track of how often the coda_inode/host_file has been mmapped */
119 	cii = ITOC(coda_inode);
120 	cii->c_mapcount++;
121 	cfi->cfi_mapcount++;
122 
123 	return host_file->f_op->mmap(host_file, vma);
124 }
125 
126 int coda_open(struct inode *coda_inode, struct file *coda_file)
127 {
128 	struct file *host_file = NULL;
129 	int error;
130 	unsigned short flags = coda_file->f_flags & (~O_EXCL);
131 	unsigned short coda_flags = coda_flags_to_cflags(flags);
132 	struct coda_file_info *cfi;
133 
134 	coda_vfs_stat.open++;
135 
136 	cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
137 	if (!cfi) {
138 		unlock_kernel();
139 		return -ENOMEM;
140 	}
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 
165 int coda_flush(struct file *coda_file)
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_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 
203 out:
204 	unlock_kernel();
205 	return err;
206 }
207 
208 int 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_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 
254 int 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_dentry;
274 		host_inode = host_dentry->d_inode;
275 		down(&host_inode->i_sem);
276 		err = host_file->f_op->fsync(host_file, host_dentry, datasync);
277 		up(&host_inode->i_sem);
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 
289 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 
301