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/cred.h>
17 #include <linux/errno.h>
18 #include <linux/spinlock.h>
19 #include <linux/string.h>
20 #include <linux/slab.h>
21 #include <linux/uaccess.h>
22
23 #include <linux/coda.h>
24 #include <linux/coda_psdev.h>
25
26 #include "coda_linux.h"
27 #include "coda_int.h"
28
29 static ssize_t
coda_file_read(struct file * coda_file,char __user * buf,size_t count,loff_t * ppos)30 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
31 {
32 struct coda_file_info *cfi;
33 struct file *host_file;
34
35 cfi = CODA_FTOC(coda_file);
36 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
37 host_file = cfi->cfi_container;
38
39 if (!host_file->f_op->read)
40 return -EINVAL;
41
42 return host_file->f_op->read(host_file, buf, count, ppos);
43 }
44
45 static ssize_t
coda_file_splice_read(struct file * coda_file,loff_t * ppos,struct pipe_inode_info * pipe,size_t count,unsigned int flags)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)
49 {
50 ssize_t (*splice_read)(struct file *, loff_t *,
51 struct pipe_inode_info *, size_t, unsigned int);
52 struct coda_file_info *cfi;
53 struct file *host_file;
54
55 cfi = CODA_FTOC(coda_file);
56 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
57 host_file = cfi->cfi_container;
58
59 splice_read = host_file->f_op->splice_read;
60 if (!splice_read)
61 splice_read = default_file_splice_read;
62
63 return splice_read(host_file, ppos, pipe, count, flags);
64 }
65
66 static ssize_t
coda_file_write(struct file * coda_file,const char __user * buf,size_t count,loff_t * ppos)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 = file_inode(coda_file);
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->write)
79 return -EINVAL;
80
81 host_inode = file_inode(host_file);
82 file_start_write(host_file);
83 mutex_lock(&coda_inode->i_mutex);
84
85 ret = host_file->f_op->write(host_file, buf, count, ppos);
86
87 coda_inode->i_size = host_inode->i_size;
88 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
89 coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
90 mutex_unlock(&coda_inode->i_mutex);
91 file_end_write(host_file);
92
93 return ret;
94 }
95
96 static int
coda_file_mmap(struct file * coda_file,struct vm_area_struct * vma)97 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
98 {
99 struct coda_file_info *cfi;
100 struct coda_inode_info *cii;
101 struct file *host_file;
102 struct inode *coda_inode, *host_inode;
103
104 cfi = CODA_FTOC(coda_file);
105 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
106 host_file = cfi->cfi_container;
107
108 if (!host_file->f_op->mmap)
109 return -ENODEV;
110
111 coda_inode = file_inode(coda_file);
112 host_inode = file_inode(host_file);
113
114 cii = ITOC(coda_inode);
115 spin_lock(&cii->c_lock);
116 coda_file->f_mapping = host_file->f_mapping;
117 if (coda_inode->i_mapping == &coda_inode->i_data)
118 coda_inode->i_mapping = host_inode->i_mapping;
119
120 /* only allow additional mmaps as long as userspace isn't changing
121 * the container file on us! */
122 else if (coda_inode->i_mapping != host_inode->i_mapping) {
123 spin_unlock(&cii->c_lock);
124 return -EBUSY;
125 }
126
127 /* keep track of how often the coda_inode/host_file has been mmapped */
128 cii->c_mapcount++;
129 cfi->cfi_mapcount++;
130 spin_unlock(&cii->c_lock);
131
132 return host_file->f_op->mmap(host_file, vma);
133 }
134
coda_open(struct inode * coda_inode,struct file * coda_file)135 int coda_open(struct inode *coda_inode, struct file *coda_file)
136 {
137 struct file *host_file = NULL;
138 int error;
139 unsigned short flags = coda_file->f_flags & (~O_EXCL);
140 unsigned short coda_flags = coda_flags_to_cflags(flags);
141 struct coda_file_info *cfi;
142
143 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
144 if (!cfi)
145 return -ENOMEM;
146
147 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
148 &host_file);
149 if (!host_file)
150 error = -EIO;
151
152 if (error) {
153 kfree(cfi);
154 return error;
155 }
156
157 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
158
159 cfi->cfi_magic = CODA_MAGIC;
160 cfi->cfi_mapcount = 0;
161 cfi->cfi_container = host_file;
162
163 BUG_ON(coda_file->private_data != NULL);
164 coda_file->private_data = cfi;
165 return 0;
166 }
167
coda_release(struct inode * coda_inode,struct file * coda_file)168 int coda_release(struct inode *coda_inode, struct file *coda_file)
169 {
170 unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
171 unsigned short coda_flags = coda_flags_to_cflags(flags);
172 struct coda_file_info *cfi;
173 struct coda_inode_info *cii;
174 struct inode *host_inode;
175 int err;
176
177 cfi = CODA_FTOC(coda_file);
178 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
179
180 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
181 coda_flags, coda_file->f_cred->fsuid);
182
183 host_inode = file_inode(cfi->cfi_container);
184 cii = ITOC(coda_inode);
185
186 /* did we mmap this file? */
187 spin_lock(&cii->c_lock);
188 if (coda_inode->i_mapping == &host_inode->i_data) {
189 cii->c_mapcount -= cfi->cfi_mapcount;
190 if (!cii->c_mapcount)
191 coda_inode->i_mapping = &coda_inode->i_data;
192 }
193 spin_unlock(&cii->c_lock);
194
195 fput(cfi->cfi_container);
196 kfree(coda_file->private_data);
197 coda_file->private_data = NULL;
198
199 /* VFS fput ignores the return value from file_operations->release, so
200 * there is no use returning an error here */
201 return 0;
202 }
203
coda_fsync(struct file * coda_file,loff_t start,loff_t end,int datasync)204 int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
205 {
206 struct file *host_file;
207 struct inode *coda_inode = file_inode(coda_file);
208 struct coda_file_info *cfi;
209 int err;
210
211 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
212 S_ISLNK(coda_inode->i_mode)))
213 return -EINVAL;
214
215 err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
216 if (err)
217 return err;
218 mutex_lock(&coda_inode->i_mutex);
219
220 cfi = CODA_FTOC(coda_file);
221 BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
222 host_file = cfi->cfi_container;
223
224 err = vfs_fsync(host_file, datasync);
225 if (!err && !datasync)
226 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
227 mutex_unlock(&coda_inode->i_mutex);
228
229 return err;
230 }
231
232 const struct file_operations coda_file_operations = {
233 .llseek = generic_file_llseek,
234 .read = coda_file_read,
235 .write = coda_file_write,
236 .mmap = coda_file_mmap,
237 .open = coda_open,
238 .release = coda_release,
239 .fsync = coda_fsync,
240 .splice_read = coda_file_splice_read,
241 };
242
243