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 |
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(f: coda_file); |
45 | struct coda_file_info *cfi = coda_ftoc(file: coda_file); |
46 | loff_t ki_pos = iocb->ki_pos; |
47 | size_t count = iov_iter_count(i: to); |
48 | ssize_t ret; |
49 | |
50 | ret = venus_access_intent(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
51 | access_intent_supported: &cfi->cfi_access_intent, |
52 | count, ppos: ki_pos, CODA_ACCESS_TYPE_READ); |
53 | if (ret) |
54 | goto finish_read; |
55 | |
56 | ret = vfs_iter_read(file: cfi->cfi_container, iter: to, ppos: &iocb->ki_pos, flags: 0); |
57 | |
58 | finish_read: |
59 | venus_access_intent(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
60 | access_intent_supported: &cfi->cfi_access_intent, |
61 | count, ppos: ki_pos, CODA_ACCESS_TYPE_READ_FINISH); |
62 | return ret; |
63 | } |
64 | |
65 | static ssize_t |
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(f: coda_file); |
70 | struct coda_file_info *cfi = coda_ftoc(file: 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(i: to); |
74 | ssize_t ret; |
75 | |
76 | ret = venus_access_intent(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
77 | access_intent_supported: &cfi->cfi_access_intent, |
78 | count, ppos: ki_pos, CODA_ACCESS_TYPE_WRITE); |
79 | if (ret) |
80 | goto finish_write; |
81 | |
82 | inode_lock(inode: coda_inode); |
83 | ret = vfs_iter_write(file: cfi->cfi_container, iter: to, ppos: &iocb->ki_pos, flags: 0); |
84 | coda_inode->i_size = file_inode(f: host_file)->i_size; |
85 | coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; |
86 | inode_set_mtime_to_ts(inode: coda_inode, ts: inode_set_ctime_current(inode: coda_inode)); |
87 | inode_unlock(inode: coda_inode); |
88 | |
89 | finish_write: |
90 | venus_access_intent(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
91 | access_intent_supported: &cfi->cfi_access_intent, |
92 | count, ppos: ki_pos, CODA_ACCESS_TYPE_WRITE_FINISH); |
93 | return ret; |
94 | } |
95 | |
96 | static ssize_t |
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(f: coda_file); |
102 | struct coda_file_info *cfi = coda_ftoc(file: 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(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
108 | access_intent_supported: &cfi->cfi_access_intent, |
109 | count: len, ppos: 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(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
117 | access_intent_supported: &cfi->cfi_access_intent, |
118 | count: len, ppos: ki_pos, CODA_ACCESS_TYPE_READ_FINISH); |
119 | return ret; |
120 | } |
121 | |
122 | static void |
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(r: &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 |
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(r: &cvm_ops->refcnt)) { |
144 | vma->vm_ops = cvm_ops->host_vm_ops; |
145 | fput(cvm_ops->coda_file); |
146 | kfree(objp: cvm_ops); |
147 | } |
148 | } |
149 | |
150 | static int |
151 | coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) |
152 | { |
153 | struct inode *coda_inode = file_inode(f: coda_file); |
154 | struct coda_file_info *cfi = coda_ftoc(file: coda_file); |
155 | struct file *host_file = cfi->cfi_container; |
156 | struct inode *host_inode = file_inode(f: 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(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
173 | access_intent_supported: &cfi->cfi_access_intent, |
174 | count, ppos, CODA_ACCESS_TYPE_MMAP); |
175 | if (ret) |
176 | return ret; |
177 | |
178 | cvm_ops = kmalloc(size: sizeof(struct coda_vm_ops), GFP_KERNEL); |
179 | if (!cvm_ops) |
180 | return -ENOMEM; |
181 | |
182 | cii = ITOC(inode: coda_inode); |
183 | spin_lock(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(lock: &cii->c_lock); |
192 | kfree(objp: 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(lock: &cii->c_lock); |
200 | |
201 | vma->vm_file = get_file(f: host_file); |
202 | ret = call_mmap(file: 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(objp: 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(r: &cvm_ops->refcnt, n: 1); |
220 | |
221 | vma->vm_ops = &cvm_ops->vm_ops; |
222 | } |
223 | return ret; |
224 | } |
225 | |
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(size: sizeof(struct coda_file_info), GFP_KERNEL); |
235 | if (!cfi) |
236 | return -ENOMEM; |
237 | |
238 | error = venus_open(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), flags: coda_flags, |
239 | f: &host_file); |
240 | if (!host_file) |
241 | error = -EIO; |
242 | |
243 | if (error) { |
244 | kfree(objp: 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 | |
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(file: coda_file); |
270 | |
271 | venus_close(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode), |
272 | flags: coda_flags, uid: coda_file->f_cred->fsuid); |
273 | |
274 | host_inode = file_inode(f: cfi->cfi_container); |
275 | cii = ITOC(inode: coda_inode); |
276 | |
277 | /* did we mmap this file? */ |
278 | spin_lock(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(lock: &cii->c_lock); |
285 | |
286 | fput(cfi->cfi_container); |
287 | kfree(objp: 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 | |
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(f: 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(mapping: coda_inode->i_mapping, lstart: start, lend: end); |
307 | if (err) |
308 | return err; |
309 | inode_lock(inode: coda_inode); |
310 | |
311 | cfi = coda_ftoc(file: coda_file); |
312 | host_file = cfi->cfi_container; |
313 | |
314 | err = vfs_fsync(file: host_file, datasync); |
315 | if (!err && !datasync) |
316 | err = venus_fsync(sb: coda_inode->i_sb, fid: coda_i2f(inode: coda_inode)); |
317 | inode_unlock(inode: 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 | |