V4L/DVB (9657): em28xx: add a functio to write on a single register
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / coda / file.c
blob466303db2df6acbd11e047338b00739408fa428d
1 /*
2 * File operations for Coda.
3 * Original version: (C) 1996 Peter Braam
4 * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
6 * Carnegie Mellon encourages users of this code to contribute improvements
7 * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
8 */
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/cred.h>
17 #include <linux/errno.h>
18 #include <linux/smp_lock.h>
19 #include <linux/string.h>
20 #include <asm/uaccess.h>
22 #include <linux/coda.h>
23 #include <linux/coda_linux.h>
24 #include <linux/coda_fs_i.h>
25 #include <linux/coda_psdev.h>
27 #include "coda_int.h"
29 static ssize_t
30 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
32 struct coda_file_info *cfi;
33 struct file *host_file;
35 cfi = CODA_FTOC(coda_file);
36 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
37 host_file = cfi->cfi_container;
39 if (!host_file->f_op || !host_file->f_op->read)
40 return -EINVAL;
42 return host_file->f_op->read(host_file, buf, count, ppos);
45 static ssize_t
46 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
47 struct pipe_inode_info *pipe, size_t count,
48 unsigned int flags)
50 struct coda_file_info *cfi;
51 struct file *host_file;
53 cfi = CODA_FTOC(coda_file);
54 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
55 host_file = cfi->cfi_container;
57 if (!host_file->f_op || !host_file->f_op->splice_read)
58 return -EINVAL;
60 return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
63 static ssize_t
64 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
66 struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
67 struct coda_file_info *cfi;
68 struct file *host_file;
69 ssize_t ret;
71 cfi = CODA_FTOC(coda_file);
72 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
73 host_file = cfi->cfi_container;
75 if (!host_file->f_op || !host_file->f_op->write)
76 return -EINVAL;
78 host_inode = host_file->f_path.dentry->d_inode;
79 mutex_lock(&coda_inode->i_mutex);
81 ret = host_file->f_op->write(host_file, buf, count, ppos);
83 coda_inode->i_size = host_inode->i_size;
84 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
85 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
86 mutex_unlock(&coda_inode->i_mutex);
88 return ret;
91 static int
92 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
94 struct coda_file_info *cfi;
95 struct coda_inode_info *cii;
96 struct file *host_file;
97 struct inode *coda_inode, *host_inode;
99 cfi = CODA_FTOC(coda_file);
100 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
101 host_file = cfi->cfi_container;
103 if (!host_file->f_op || !host_file->f_op->mmap)
104 return -ENODEV;
106 coda_inode = coda_file->f_path.dentry->d_inode;
107 host_inode = host_file->f_path.dentry->d_inode;
108 coda_file->f_mapping = host_file->f_mapping;
109 if (coda_inode->i_mapping == &coda_inode->i_data)
110 coda_inode->i_mapping = host_inode->i_mapping;
112 /* only allow additional mmaps as long as userspace isn't changing
113 * the container file on us! */
114 else if (coda_inode->i_mapping != host_inode->i_mapping)
115 return -EBUSY;
117 /* keep track of how often the coda_inode/host_file has been mmapped */
118 cii = ITOC(coda_inode);
119 cii->c_mapcount++;
120 cfi->cfi_mapcount++;
122 return host_file->f_op->mmap(host_file, vma);
125 int coda_open(struct inode *coda_inode, struct file *coda_file)
127 struct file *host_file = NULL;
128 int error;
129 unsigned short flags = coda_file->f_flags & (~O_EXCL);
130 unsigned short coda_flags = coda_flags_to_cflags(flags);
131 struct coda_file_info *cfi;
133 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
134 if (!cfi)
135 return -ENOMEM;
137 lock_kernel();
139 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
140 &host_file);
141 if (!host_file)
142 error = -EIO;
144 if (error) {
145 kfree(cfi);
146 unlock_kernel();
147 return error;
150 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
152 cfi->cfi_magic = CODA_MAGIC;
153 cfi->cfi_mapcount = 0;
154 cfi->cfi_container = host_file;
156 BUG_ON(coda_file->private_data != NULL);
157 coda_file->private_data = cfi;
159 unlock_kernel();
160 return 0;
163 int coda_release(struct inode *coda_inode, struct file *coda_file)
165 unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
166 unsigned short coda_flags = coda_flags_to_cflags(flags);
167 struct coda_file_info *cfi;
168 struct coda_inode_info *cii;
169 struct inode *host_inode;
170 int err = 0;
172 lock_kernel();
174 cfi = CODA_FTOC(coda_file);
175 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
177 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
178 coda_flags, coda_file->f_cred->fsuid);
180 host_inode = cfi->cfi_container->f_path.dentry->d_inode;
181 cii = ITOC(coda_inode);
183 /* did we mmap this file? */
184 if (coda_inode->i_mapping == &host_inode->i_data) {
185 cii->c_mapcount -= cfi->cfi_mapcount;
186 if (!cii->c_mapcount)
187 coda_inode->i_mapping = &coda_inode->i_data;
190 fput(cfi->cfi_container);
191 kfree(coda_file->private_data);
192 coda_file->private_data = NULL;
194 unlock_kernel();
196 /* VFS fput ignores the return value from file_operations->release, so
197 * there is no use returning an error here */
198 return 0;
201 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
203 struct file *host_file;
204 struct dentry *host_dentry;
205 struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
206 struct coda_file_info *cfi;
207 int err = 0;
209 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
210 S_ISLNK(coda_inode->i_mode)))
211 return -EINVAL;
213 cfi = CODA_FTOC(coda_file);
214 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
215 host_file = cfi->cfi_container;
217 if (host_file->f_op && host_file->f_op->fsync) {
218 host_dentry = host_file->f_path.dentry;
219 host_inode = host_dentry->d_inode;
220 mutex_lock(&host_inode->i_mutex);
221 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
222 mutex_unlock(&host_inode->i_mutex);
225 if ( !err && !datasync ) {
226 lock_kernel();
227 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
228 unlock_kernel();
231 return err;
234 const struct file_operations coda_file_operations = {
235 .llseek = generic_file_llseek,
236 .read = coda_file_read,
237 .write = coda_file_write,
238 .mmap = coda_file_mmap,
239 .open = coda_open,
240 .release = coda_release,
241 .fsync = coda_fsync,
242 .splice_read = coda_file_splice_read,