1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * File operations for Coda.
4 * Original version: (C) 1996 Peter Braam
5 * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
6 *
7 * Carnegie Mellon encourages users of this code to contribute improvements
8 * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
9 */
10
11 #include <linux/refcount.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/time.h>
15 #include <linux/file.h>
16 #include <linux/fs.h>
17 #include <linux/pagemap.h>
18 #include <linux/stat.h>
19 #include <linux/cred.h>
20 #include <linux/errno.h>
21 #include <linux/spinlock.h>
22 #include <linux/string.h>
23 #include <linux/slab.h>
24 #include <linux/uaccess.h>
25 #include <linux/uio.h>
26 #include <linux/splice.h>
27
28 #include <linux/coda.h>
29 #include "coda_psdev.h"
30 #include "coda_linux.h"
31 #include "coda_int.h"
32
33 struct coda_vm_ops {
34 refcount_t refcnt;
35 struct file *coda_file;
36 const struct vm_operations_struct *host_vm_ops;
37 struct vm_operations_struct vm_ops;
38 };
39
40 static ssize_t
coda_file_read_iter(struct kiocb * iocb,struct iov_iter * to)41 coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
42 {
43 struct file *coda_file = iocb->ki_filp;
44 struct inode *coda_inode = file_inode(coda_file);
45 struct coda_file_info *cfi = coda_ftoc(coda_file);
46 loff_t ki_pos = iocb->ki_pos;
47 size_t count = iov_iter_count(to);
48 ssize_t ret;
49
50 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
51 &cfi->cfi_access_intent,
52 count, ki_pos, CODA_ACCESS_TYPE_READ);
53 if (ret)
54 goto finish_read;
55
56 ret = vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
57
58 finish_read:
59 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
60 &cfi->cfi_access_intent,
61 count, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
62 return ret;
63 }
64
65 static ssize_t
coda_file_write_iter(struct kiocb * iocb,struct iov_iter * to)66 coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
67 {
68 struct file *coda_file = iocb->ki_filp;
69 struct inode *coda_inode = file_inode(coda_file);
70 struct coda_file_info *cfi = coda_ftoc(coda_file);
71 struct file *host_file = cfi->cfi_container;
72 loff_t ki_pos = iocb->ki_pos;
73 size_t count = iov_iter_count(to);
74 ssize_t ret;
75
76 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
77 &cfi->cfi_access_intent,
78 count, ki_pos, CODA_ACCESS_TYPE_WRITE);
79 if (ret)
80 goto finish_write;
81
82 file_start_write(host_file);
83 inode_lock(coda_inode);
84 ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
85 coda_inode->i_size = file_inode(host_file)->i_size;
86 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
87 coda_inode->i_mtime = inode_set_ctime_current(coda_inode);
88 inode_unlock(coda_inode);
89 file_end_write(host_file);
90
91 finish_write:
92 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
93 &cfi->cfi_access_intent,
94 count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH);
95 return ret;
96 }
97
98 static ssize_t
coda_file_splice_read(struct file * coda_file,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)99 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
100 struct pipe_inode_info *pipe,
101 size_t len, unsigned int flags)
102 {
103 struct inode *coda_inode = file_inode(coda_file);
104 struct coda_file_info *cfi = coda_ftoc(coda_file);
105 struct file *in = cfi->cfi_container;
106 loff_t ki_pos = *ppos;
107 ssize_t ret;
108
109 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
110 &cfi->cfi_access_intent,
111 len, ki_pos, CODA_ACCESS_TYPE_READ);
112 if (ret)
113 goto finish_read;
114
115 ret = vfs_splice_read(in, ppos, pipe, len, flags);
116
117 finish_read:
118 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
119 &cfi->cfi_access_intent,
120 len, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
121 return ret;
122 }
123
124 static void
coda_vm_open(struct vm_area_struct * vma)125 coda_vm_open(struct vm_area_struct *vma)
126 {
127 struct coda_vm_ops *cvm_ops =
128 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
129
130 refcount_inc(&cvm_ops->refcnt);
131
132 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
133 cvm_ops->host_vm_ops->open(vma);
134 }
135
136 static void
coda_vm_close(struct vm_area_struct * vma)137 coda_vm_close(struct vm_area_struct *vma)
138 {
139 struct coda_vm_ops *cvm_ops =
140 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
141
142 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
143 cvm_ops->host_vm_ops->close(vma);
144
145 if (refcount_dec_and_test(&cvm_ops->refcnt)) {
146 vma->vm_ops = cvm_ops->host_vm_ops;
147 fput(cvm_ops->coda_file);
148 kfree(cvm_ops);
149 }
150 }
151
152 static int
coda_file_mmap(struct file * coda_file,struct vm_area_struct * vma)153 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
154 {
155 struct inode *coda_inode = file_inode(coda_file);
156 struct coda_file_info *cfi = coda_ftoc(coda_file);
157 struct file *host_file = cfi->cfi_container;
158 struct inode *host_inode = file_inode(host_file);
159 struct coda_inode_info *cii;
160 struct coda_vm_ops *cvm_ops;
161 loff_t ppos;
162 size_t count;
163 int ret;
164
165 if (!host_file->f_op->mmap)
166 return -ENODEV;
167
168 if (WARN_ON(coda_file != vma->vm_file))
169 return -EIO;
170
171 count = vma->vm_end - vma->vm_start;
172 ppos = vma->vm_pgoff * PAGE_SIZE;
173
174 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
175 &cfi->cfi_access_intent,
176 count, ppos, CODA_ACCESS_TYPE_MMAP);
177 if (ret)
178 return ret;
179
180 cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
181 if (!cvm_ops)
182 return -ENOMEM;
183
184 cii = ITOC(coda_inode);
185 spin_lock(&cii->c_lock);
186 coda_file->f_mapping = host_file->f_mapping;
187 if (coda_inode->i_mapping == &coda_inode->i_data)
188 coda_inode->i_mapping = host_inode->i_mapping;
189
190 /* only allow additional mmaps as long as userspace isn't changing
191 * the container file on us! */
192 else if (coda_inode->i_mapping != host_inode->i_mapping) {
193 spin_unlock(&cii->c_lock);
194 kfree(cvm_ops);
195 return -EBUSY;
196 }
197
198 /* keep track of how often the coda_inode/host_file has been mmapped */
199 cii->c_mapcount++;
200 cfi->cfi_mapcount++;
201 spin_unlock(&cii->c_lock);
202
203 vma->vm_file = get_file(host_file);
204 ret = call_mmap(vma->vm_file, vma);
205
206 if (ret) {
207 /* if call_mmap fails, our caller will put host_file so we
208 * should drop the reference to the coda_file that we got.
209 */
210 fput(coda_file);
211 kfree(cvm_ops);
212 } else {
213 /* here we add redirects for the open/close vm_operations */
214 cvm_ops->host_vm_ops = vma->vm_ops;
215 if (vma->vm_ops)
216 cvm_ops->vm_ops = *vma->vm_ops;
217
218 cvm_ops->vm_ops.open = coda_vm_open;
219 cvm_ops->vm_ops.close = coda_vm_close;
220 cvm_ops->coda_file = coda_file;
221 refcount_set(&cvm_ops->refcnt, 1);
222
223 vma->vm_ops = &cvm_ops->vm_ops;
224 }
225 return ret;
226 }
227
coda_open(struct inode * coda_inode,struct file * coda_file)228 int coda_open(struct inode *coda_inode, struct file *coda_file)
229 {
230 struct file *host_file = NULL;
231 int error;
232 unsigned short flags = coda_file->f_flags & (~O_EXCL);
233 unsigned short coda_flags = coda_flags_to_cflags(flags);
234 struct coda_file_info *cfi;
235
236 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
237 if (!cfi)
238 return -ENOMEM;
239
240 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
241 &host_file);
242 if (!host_file)
243 error = -EIO;
244
245 if (error) {
246 kfree(cfi);
247 return error;
248 }
249
250 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
251
252 cfi->cfi_magic = CODA_MAGIC;
253 cfi->cfi_mapcount = 0;
254 cfi->cfi_container = host_file;
255 /* assume access intents are supported unless we hear otherwise */
256 cfi->cfi_access_intent = true;
257
258 BUG_ON(coda_file->private_data != NULL);
259 coda_file->private_data = cfi;
260 return 0;
261 }
262
coda_release(struct inode * coda_inode,struct file * coda_file)263 int coda_release(struct inode *coda_inode, struct file *coda_file)
264 {
265 unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
266 unsigned short coda_flags = coda_flags_to_cflags(flags);
267 struct coda_file_info *cfi;
268 struct coda_inode_info *cii;
269 struct inode *host_inode;
270
271 cfi = coda_ftoc(coda_file);
272
273 venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
274 coda_flags, coda_file->f_cred->fsuid);
275
276 host_inode = file_inode(cfi->cfi_container);
277 cii = ITOC(coda_inode);
278
279 /* did we mmap this file? */
280 spin_lock(&cii->c_lock);
281 if (coda_inode->i_mapping == &host_inode->i_data) {
282 cii->c_mapcount -= cfi->cfi_mapcount;
283 if (!cii->c_mapcount)
284 coda_inode->i_mapping = &coda_inode->i_data;
285 }
286 spin_unlock(&cii->c_lock);
287
288 fput(cfi->cfi_container);
289 kfree(coda_file->private_data);
290 coda_file->private_data = NULL;
291
292 /* VFS fput ignores the return value from file_operations->release, so
293 * there is no use returning an error here */
294 return 0;
295 }
296
coda_fsync(struct file * coda_file,loff_t start,loff_t end,int datasync)297 int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
298 {
299 struct file *host_file;
300 struct inode *coda_inode = file_inode(coda_file);
301 struct coda_file_info *cfi;
302 int err;
303
304 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
305 S_ISLNK(coda_inode->i_mode)))
306 return -EINVAL;
307
308 err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
309 if (err)
310 return err;
311 inode_lock(coda_inode);
312
313 cfi = coda_ftoc(coda_file);
314 host_file = cfi->cfi_container;
315
316 err = vfs_fsync(host_file, datasync);
317 if (!err && !datasync)
318 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
319 inode_unlock(coda_inode);
320
321 return err;
322 }
323
324 const struct file_operations coda_file_operations = {
325 .llseek = generic_file_llseek,
326 .read_iter = coda_file_read_iter,
327 .write_iter = coda_file_write_iter,
328 .mmap = coda_file_mmap,
329 .open = coda_open,
330 .release = coda_release,
331 .fsync = coda_fsync,
332 .splice_read = coda_file_splice_read,
333 };
334