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 inode_lock(coda_inode);
83 ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
84 coda_inode->i_size = file_inode(host_file)->i_size;
85 coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
86 inode_set_mtime_to_ts(coda_inode, inode_set_ctime_current(coda_inode));
87 inode_unlock(coda_inode);
88
89 finish_write:
90 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
91 &cfi->cfi_access_intent,
92 count, ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH);
93 return ret;
94 }
95
96 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)97 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
98 struct pipe_inode_info *pipe,
99 size_t len, unsigned int flags)
100 {
101 struct inode *coda_inode = file_inode(coda_file);
102 struct coda_file_info *cfi = coda_ftoc(coda_file);
103 struct file *in = cfi->cfi_container;
104 loff_t ki_pos = *ppos;
105 ssize_t ret;
106
107 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
108 &cfi->cfi_access_intent,
109 len, ki_pos, CODA_ACCESS_TYPE_READ);
110 if (ret)
111 goto finish_read;
112
113 ret = vfs_splice_read(in, ppos, pipe, len, flags);
114
115 finish_read:
116 venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
117 &cfi->cfi_access_intent,
118 len, ki_pos, CODA_ACCESS_TYPE_READ_FINISH);
119 return ret;
120 }
121
122 static void
coda_vm_open(struct vm_area_struct * vma)123 coda_vm_open(struct vm_area_struct *vma)
124 {
125 struct coda_vm_ops *cvm_ops =
126 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
127
128 refcount_inc(&cvm_ops->refcnt);
129
130 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open)
131 cvm_ops->host_vm_ops->open(vma);
132 }
133
134 static void
coda_vm_close(struct vm_area_struct * vma)135 coda_vm_close(struct vm_area_struct *vma)
136 {
137 struct coda_vm_ops *cvm_ops =
138 container_of(vma->vm_ops, struct coda_vm_ops, vm_ops);
139
140 if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close)
141 cvm_ops->host_vm_ops->close(vma);
142
143 if (refcount_dec_and_test(&cvm_ops->refcnt)) {
144 vma->vm_ops = cvm_ops->host_vm_ops;
145 fput(cvm_ops->coda_file);
146 kfree(cvm_ops);
147 }
148 }
149
150 static int
coda_file_mmap(struct file * coda_file,struct vm_area_struct * vma)151 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
152 {
153 struct inode *coda_inode = file_inode(coda_file);
154 struct coda_file_info *cfi = coda_ftoc(coda_file);
155 struct file *host_file = cfi->cfi_container;
156 struct inode *host_inode = file_inode(host_file);
157 struct coda_inode_info *cii;
158 struct coda_vm_ops *cvm_ops;
159 loff_t ppos;
160 size_t count;
161 int ret;
162
163 if (!host_file->f_op->mmap)
164 return -ENODEV;
165
166 if (WARN_ON(coda_file != vma->vm_file))
167 return -EIO;
168
169 count = vma->vm_end - vma->vm_start;
170 ppos = vma->vm_pgoff * PAGE_SIZE;
171
172 ret = venus_access_intent(coda_inode->i_sb, coda_i2f(coda_inode),
173 &cfi->cfi_access_intent,
174 count, ppos, CODA_ACCESS_TYPE_MMAP);
175 if (ret)
176 return ret;
177
178 cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL);
179 if (!cvm_ops)
180 return -ENOMEM;
181
182 cii = ITOC(coda_inode);
183 spin_lock(&cii->c_lock);
184 coda_file->f_mapping = host_file->f_mapping;
185 if (coda_inode->i_mapping == &coda_inode->i_data)
186 coda_inode->i_mapping = host_inode->i_mapping;
187
188 /* only allow additional mmaps as long as userspace isn't changing
189 * the container file on us! */
190 else if (coda_inode->i_mapping != host_inode->i_mapping) {
191 spin_unlock(&cii->c_lock);
192 kfree(cvm_ops);
193 return -EBUSY;
194 }
195
196 /* keep track of how often the coda_inode/host_file has been mmapped */
197 cii->c_mapcount++;
198 cfi->cfi_mapcount++;
199 spin_unlock(&cii->c_lock);
200
201 vma->vm_file = get_file(host_file);
202 ret = call_mmap(vma->vm_file, vma);
203
204 if (ret) {
205 /* if call_mmap fails, our caller will put host_file so we
206 * should drop the reference to the coda_file that we got.
207 */
208 fput(coda_file);
209 kfree(cvm_ops);
210 } else {
211 /* here we add redirects for the open/close vm_operations */
212 cvm_ops->host_vm_ops = vma->vm_ops;
213 if (vma->vm_ops)
214 cvm_ops->vm_ops = *vma->vm_ops;
215
216 cvm_ops->vm_ops.open = coda_vm_open;
217 cvm_ops->vm_ops.close = coda_vm_close;
218 cvm_ops->coda_file = coda_file;
219 refcount_set(&cvm_ops->refcnt, 1);
220
221 vma->vm_ops = &cvm_ops->vm_ops;
222 }
223 return ret;
224 }
225
coda_open(struct inode * coda_inode,struct file * coda_file)226 int coda_open(struct inode *coda_inode, struct file *coda_file)
227 {
228 struct file *host_file = NULL;
229 int error;
230 unsigned short flags = coda_file->f_flags & (~O_EXCL);
231 unsigned short coda_flags = coda_flags_to_cflags(flags);
232 struct coda_file_info *cfi;
233
234 cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
235 if (!cfi)
236 return -ENOMEM;
237
238 error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
239 &host_file);
240 if (!host_file)
241 error = -EIO;
242
243 if (error) {
244 kfree(cfi);
245 return error;
246 }
247
248 host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
249
250 cfi->cfi_magic = CODA_MAGIC;
251 cfi->cfi_mapcount = 0;
252 cfi->cfi_container = host_file;
253 /* assume access intents are supported unless we hear otherwise */
254 cfi->cfi_access_intent = true;
255
256 BUG_ON(coda_file->private_data != NULL);
257 coda_file->private_data = cfi;
258 return 0;
259 }
260
coda_release(struct inode * coda_inode,struct file * coda_file)261 int coda_release(struct inode *coda_inode, struct file *coda_file)
262 {
263 unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
264 unsigned short coda_flags = coda_flags_to_cflags(flags);
265 struct coda_file_info *cfi;
266 struct coda_inode_info *cii;
267 struct inode *host_inode;
268
269 cfi = coda_ftoc(coda_file);
270
271 venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
272 coda_flags, coda_file->f_cred->fsuid);
273
274 host_inode = file_inode(cfi->cfi_container);
275 cii = ITOC(coda_inode);
276
277 /* did we mmap this file? */
278 spin_lock(&cii->c_lock);
279 if (coda_inode->i_mapping == &host_inode->i_data) {
280 cii->c_mapcount -= cfi->cfi_mapcount;
281 if (!cii->c_mapcount)
282 coda_inode->i_mapping = &coda_inode->i_data;
283 }
284 spin_unlock(&cii->c_lock);
285
286 fput(cfi->cfi_container);
287 kfree(coda_file->private_data);
288 coda_file->private_data = NULL;
289
290 /* VFS fput ignores the return value from file_operations->release, so
291 * there is no use returning an error here */
292 return 0;
293 }
294
coda_fsync(struct file * coda_file,loff_t start,loff_t end,int datasync)295 int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
296 {
297 struct file *host_file;
298 struct inode *coda_inode = file_inode(coda_file);
299 struct coda_file_info *cfi;
300 int err;
301
302 if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
303 S_ISLNK(coda_inode->i_mode)))
304 return -EINVAL;
305
306 err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
307 if (err)
308 return err;
309 inode_lock(coda_inode);
310
311 cfi = coda_ftoc(coda_file);
312 host_file = cfi->cfi_container;
313
314 err = vfs_fsync(host_file, datasync);
315 if (!err && !datasync)
316 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
317 inode_unlock(coda_inode);
318
319 return err;
320 }
321
322 const struct file_operations coda_file_operations = {
323 .llseek = generic_file_llseek,
324 .read_iter = coda_file_read_iter,
325 .write_iter = coda_file_write_iter,
326 .mmap = coda_file_mmap,
327 .open = coda_open,
328 .release = coda_release,
329 .fsync = coda_fsync,
330 .splice_read = coda_file_splice_read,
331 };
332