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
26 #include "coda_int.h"
27
28 static ssize_t
29 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
30 {
31 struct coda_file_info *cfi;
32 struct file *host_file;
33
34 cfi = CODA_FTOC(coda_file);
35 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
36 host_file = cfi->cfi_container;
37
38 if (!host_file->f_op || !host_file->f_op->read)
39 return -EINVAL;
40
41 return host_file->f_op->read(host_file, buf, count, ppos);
42 }
43
44 static ssize_t
45 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
46 struct pipe_inode_info *pipe, size_t count,
47 unsigned int flags)
48 {
49 struct coda_file_info *cfi;
50 struct file *host_file;
51
52 cfi = CODA_FTOC(coda_file);
53 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
54 host_file = cfi->cfi_container;
55
56 if (!host_file->f_op || !host_file->f_op->splice_read)
57 return -EINVAL;
58
59 return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
60 }
61
62 static ssize_t
63 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
64 {
65 struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
66 struct coda_file_info *cfi;
67 struct file *host_file;
68 ssize_t ret;
69
70 cfi = CODA_FTOC(coda_file);
71 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
72 host_file = cfi->cfi_container;
73
74 if (!host_file->f_op || !host_file->f_op->write)
75 return -EINVAL;
76
77 host_inode = host_file->f_path.dentry->d_inode;
78 mutex_lock(&coda_inode->i_mutex);
79
80 ret = host_file->f_op->write(host_file, buf, count, ppos);
81
82 coda_inode->i_size = host_inode->i_size;
83 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
84 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
85 mutex_unlock(&coda_inode->i_mutex);
86
87 return ret;
88 }
89
90 static int
91 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
92 {
93 struct coda_file_info *cfi;
94 struct coda_inode_info *cii;
95 struct file *host_file;
96 struct inode *coda_inode, *host_inode;
97
98 cfi = CODA_FTOC(coda_file);
99 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
100 host_file = cfi->cfi_container;
101
102 if (!host_file->f_op || !host_file->f_op->mmap)
103 return -ENODEV;
104
105 coda_inode = coda_file->f_path.dentry->d_inode;
106 host_inode = host_file->f_path.dentry->d_inode;
107 coda_file->f_mapping = host_file->f_mapping;
108 if (coda_inode->i_mapping == &coda_inode->i_data)
109 coda_inode->i_mapping = host_inode->i_mapping;
110
111 /* only allow additional mmaps as long as userspace isn't changing
112 * the container file on us! */
113 else if (coda_inode->i_mapping != host_inode->i_mapping)
114 return -EBUSY;
115
116 /* keep track of how often the coda_inode/host_file has been mmapped */
117 cii = ITOC(coda_inode);
118 cii->c_mapcount++;
119 cfi->cfi_mapcount++;
120
121 return host_file->f_op->mmap(host_file, vma);
122 }
123
124 int coda_open(struct inode *coda_inode, struct file *coda_file)
125 {
126 struct file *host_file = NULL;
127 int error;
128 unsigned short flags = coda_file->f_flags & (~O_EXCL);
129 unsigned short coda_flags = coda_flags_to_cflags(flags);
130 struct coda_file_info *cfi;
131
132 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
133 if (!cfi)
134 return -ENOMEM;
135
136 lock_kernel();
137
138 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
139 &host_file);
140 if (!host_file)
141 error = -EIO;
142
143 if (error) {
144 kfree(cfi);
145 unlock_kernel();
146 return error;
147 }
148
149 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
150
151 cfi->cfi_magic = CODA_MAGIC;
152 cfi->cfi_mapcount = 0;
153 cfi->cfi_container = host_file;
154
155 BUG_ON(coda_file->private_data != NULL);
156 coda_file->private_data = cfi;
157
158 unlock_kernel();
159 return 0;
160 }
161
162 int coda_release(struct inode *coda_inode, struct file *coda_file)
163 {
164 unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
165 unsigned short coda_flags = coda_flags_to_cflags(flags);
166 struct coda_file_info *cfi;
167 struct coda_inode_info *cii;
168 struct inode *host_inode;
169 int err = 0;
170
171 lock_kernel();
172
173 cfi = CODA_FTOC(coda_file);
174 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
175
176 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
177 coda_flags, coda_file->f_uid);
178
179 host_inode = cfi->cfi_container->f_path.dentry->d_inode;
180 cii = ITOC(coda_inode);
181
182 /* did we mmap this file? */
183 if (coda_inode->i_mapping == &host_inode->i_data) {
184 cii->c_mapcount -= cfi->cfi_mapcount;
185 if (!cii->c_mapcount)
186 coda_inode->i_mapping = &coda_inode->i_data;
187 }
188
189 fput(cfi->cfi_container);
190 kfree(coda_file->private_data);
191 coda_file->private_data = NULL;
192
193 unlock_kernel();
194
195 /* VFS fput ignores the return value from file_operations->release, so
196 * there is no use returning an error here */
197 return 0;
198 }
199
200 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
201 {
202 struct file *host_file;
203 struct dentry *host_dentry;
204 struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
205 struct coda_file_info *cfi;
206 int err = 0;
207
208 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
209 S_ISLNK(coda_inode->i_mode)))
210 return -EINVAL;
211
212 cfi = CODA_FTOC(coda_file);
213 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
214 host_file = cfi->cfi_container;
215
216 if (host_file->f_op && host_file->f_op->fsync) {
217 host_dentry = host_file->f_path.dentry;
218 host_inode = host_dentry->d_inode;
219 mutex_lock(&host_inode->i_mutex);
220 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
221 mutex_unlock(&host_inode->i_mutex);
222 }
223
224 if ( !err && !datasync ) {
225 lock_kernel();
226 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
227 unlock_kernel();
228 }
229
230 return err;
231 }
232
233 const struct file_operations coda_file_operations = {
234 .llseek = generic_file_llseek,
235 .read = coda_file_read,
236 .write = coda_file_write,
237 .mmap = coda_file_mmap,
238 .open = coda_open,
239 .release = coda_release,
240 .fsync = coda_fsync,
241 .splice_read = coda_file_splice_read,
242 };
243
244
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