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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 <asm/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 |
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 || !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 |
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 |
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_path.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_path.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_path.dentry->d_inode; |
110 | host_inode = host_file->f_path.dentry->d_inode; |
111 | |
112 | cii = ITOC(coda_inode); |
113 | spin_lock(&cii->c_lock); |
114 | coda_file->f_mapping = host_file->f_mapping; |
115 | if (coda_inode->i_mapping == &coda_inode->i_data) |
116 | coda_inode->i_mapping = host_inode->i_mapping; |
117 | |
118 | /* only allow additional mmaps as long as userspace isn't changing |
119 | * the container file on us! */ |
120 | else if (coda_inode->i_mapping != host_inode->i_mapping) { |
121 | spin_unlock(&cii->c_lock); |
122 | return -EBUSY; |
123 | } |
124 | |
125 | /* keep track of how often the coda_inode/host_file has been mmapped */ |
126 | cii->c_mapcount++; |
127 | cfi->cfi_mapcount++; |
128 | spin_unlock(&cii->c_lock); |
129 | |
130 | return host_file->f_op->mmap(host_file, vma); |
131 | } |
132 | |
133 | int coda_open(struct inode *coda_inode, struct file *coda_file) |
134 | { |
135 | struct file *host_file = NULL; |
136 | int error; |
137 | unsigned short flags = coda_file->f_flags & (~O_EXCL); |
138 | unsigned short coda_flags = coda_flags_to_cflags(flags); |
139 | struct coda_file_info *cfi; |
140 | |
141 | cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); |
142 | if (!cfi) |
143 | return -ENOMEM; |
144 | |
145 | error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, |
146 | &host_file); |
147 | if (!host_file) |
148 | error = -EIO; |
149 | |
150 | if (error) { |
151 | kfree(cfi); |
152 | return error; |
153 | } |
154 | |
155 | host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); |
156 | |
157 | cfi->cfi_magic = CODA_MAGIC; |
158 | cfi->cfi_mapcount = 0; |
159 | cfi->cfi_container = host_file; |
160 | |
161 | BUG_ON(coda_file->private_data != NULL); |
162 | coda_file->private_data = cfi; |
163 | return 0; |
164 | } |
165 | |
166 | int coda_release(struct inode *coda_inode, struct file *coda_file) |
167 | { |
168 | unsigned short flags = (coda_file->f_flags) & (~O_EXCL); |
169 | unsigned short coda_flags = coda_flags_to_cflags(flags); |
170 | struct coda_file_info *cfi; |
171 | struct coda_inode_info *cii; |
172 | struct inode *host_inode; |
173 | int err; |
174 | |
175 | cfi = CODA_FTOC(coda_file); |
176 | BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); |
177 | |
178 | err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), |
179 | coda_flags, coda_file->f_cred->fsuid); |
180 | |
181 | host_inode = cfi->cfi_container->f_path.dentry->d_inode; |
182 | cii = ITOC(coda_inode); |
183 | |
184 | /* did we mmap this file? */ |
185 | spin_lock(&cii->c_lock); |
186 | if (coda_inode->i_mapping == &host_inode->i_data) { |
187 | cii->c_mapcount -= cfi->cfi_mapcount; |
188 | if (!cii->c_mapcount) |
189 | coda_inode->i_mapping = &coda_inode->i_data; |
190 | } |
191 | spin_unlock(&cii->c_lock); |
192 | |
193 | fput(cfi->cfi_container); |
194 | kfree(coda_file->private_data); |
195 | coda_file->private_data = NULL; |
196 | |
197 | /* VFS fput ignores the return value from file_operations->release, so |
198 | * there is no use returning an error here */ |
199 | return 0; |
200 | } |
201 | |
202 | int coda_fsync(struct file *coda_file, int datasync) |
203 | { |
204 | struct file *host_file; |
205 | struct inode *coda_inode = coda_file->f_path.dentry->d_inode; |
206 | struct coda_file_info *cfi; |
207 | int err; |
208 | |
209 | if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || |
210 | S_ISLNK(coda_inode->i_mode))) |
211 | return -EINVAL; |
212 | |
213 | cfi = CODA_FTOC(coda_file); |
214 | BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); |
215 | host_file = cfi->cfi_container; |
216 | |
217 | err = vfs_fsync(host_file, datasync); |
218 | if (!err && !datasync) |
219 | err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); |
220 | |
221 | return err; |
222 | } |
223 | |
224 | const struct file_operations coda_file_operations = { |
225 | .llseek = generic_file_llseek, |
226 | .read = coda_file_read, |
227 | .write = coda_file_write, |
228 | .mmap = coda_file_mmap, |
229 | .open = coda_open, |
230 | .release = coda_release, |
231 | .fsync = coda_fsync, |
232 | .splice_read = coda_file_splice_read, |
233 | }; |
234 | |
235 |
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