1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * This file contians vfs file ops for 9P2000.
4 *
5 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
7 */
8
9 #include <linux/module.h>
10 #include <linux/errno.h>
11 #include <linux/fs.h>
12 #include <linux/filelock.h>
13 #include <linux/sched.h>
14 #include <linux/file.h>
15 #include <linux/stat.h>
16 #include <linux/string.h>
17 #include <linux/list.h>
18 #include <linux/pagemap.h>
19 #include <linux/utsname.h>
20 #include <linux/uaccess.h>
21 #include <linux/uio.h>
22 #include <linux/slab.h>
23 #include <net/9p/9p.h>
24 #include <net/9p/client.h>
25
26 #include "v9fs.h"
27 #include "v9fs_vfs.h"
28 #include "fid.h"
29 #include "cache.h"
30
31 static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
32
33 /**
34 * v9fs_file_open - open a file (or directory)
35 * @inode: inode to be opened
36 * @file: file being opened
37 *
38 */
39
40 int v9fs_file_open(struct inode *inode, struct file *file)
41 {
42 int err;
43 struct v9fs_session_info *v9ses;
44 struct p9_fid *fid;
45 int omode;
46
47 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
48 v9ses = v9fs_inode2v9ses(inode);
49 if (v9fs_proto_dotl(v9ses))
50 omode = v9fs_open_to_dotl_flags(file->f_flags);
51 else
52 omode = v9fs_uflags2omode(file->f_flags,
53 v9fs_proto_dotu(v9ses));
54 fid = file->private_data;
55 if (!fid) {
56 fid = v9fs_fid_clone(file_dentry(file));
57 if (IS_ERR(fid))
58 return PTR_ERR(fid);
59
60 if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {
61 int writeback_omode = (omode & ~P9_OWRITE) | P9_ORDWR;
62
63 p9_debug(P9_DEBUG_CACHE, "write-only file with writeback enabled, try opening O_RDWR\n");
64 err = p9_client_open(fid, writeback_omode);
65 if (err < 0) {
66 p9_debug(P9_DEBUG_CACHE, "could not open O_RDWR, disabling caches\n");
67 err = p9_client_open(fid, omode);
68 fid->mode |= P9L_DIRECT;
69 }
70 } else {
71 err = p9_client_open(fid, omode);
72 }
73 if (err < 0) {
74 p9_fid_put(fid);
75 return err;
76 }
77 if ((file->f_flags & O_APPEND) &&
78 (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
79 generic_file_llseek(file, 0, SEEK_END);
80
81 file->private_data = fid;
82 }
83
84 #ifdef CONFIG_9P_FSCACHE
85 if (v9ses->cache & CACHE_FSCACHE)
86 fscache_use_cookie(v9fs_inode_cookie(V9FS_I(inode)),
87 file->f_mode & FMODE_WRITE);
88 #endif
89 v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
90 v9fs_open_fid_add(inode, &fid);
91 return 0;
92 }
93
94 /**
95 * v9fs_file_lock - lock a file (or directory)
96 * @filp: file to be locked
97 * @cmd: lock command
98 * @fl: file lock structure
99 *
100 * Bugs: this looks like a local only lock, we should extend into 9P
101 * by using open exclusive
102 */
103
104 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
105 {
106 struct inode *inode = file_inode(filp);
107
108 p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
109
110 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
111 filemap_write_and_wait(inode->i_mapping);
112 invalidate_mapping_pages(&inode->i_data, 0, -1);
113 }
114
115 return 0;
116 }
117
118 static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
119 {
120 struct p9_flock flock;
121 struct p9_fid *fid;
122 uint8_t status = P9_LOCK_ERROR;
123 int res = 0;
124 struct v9fs_session_info *v9ses;
125
126 fid = filp->private_data;
127 BUG_ON(fid == NULL);
128
129 BUG_ON((fl->c.flc_flags & FL_POSIX) != FL_POSIX);
130
131 res = locks_lock_file_wait(filp, fl);
132 if (res < 0)
133 goto out;
134
135 /* convert posix lock to p9 tlock args */
136 memset(&flock, 0, sizeof(flock));
137 /* map the lock type */
138 switch (fl->c.flc_type) {
139 case F_RDLCK:
140 flock.type = P9_LOCK_TYPE_RDLCK;
141 break;
142 case F_WRLCK:
143 flock.type = P9_LOCK_TYPE_WRLCK;
144 break;
145 case F_UNLCK:
146 flock.type = P9_LOCK_TYPE_UNLCK;
147 break;
148 }
149 flock.start = fl->fl_start;
150 if (fl->fl_end == OFFSET_MAX)
151 flock.length = 0;
152 else
153 flock.length = fl->fl_end - fl->fl_start + 1;
154 flock.proc_id = fl->c.flc_pid;
155 flock.client_id = fid->clnt->name;
156 if (IS_SETLKW(cmd))
157 flock.flags = P9_LOCK_FLAGS_BLOCK;
158
159 v9ses = v9fs_inode2v9ses(file_inode(filp));
160
161 /*
162 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
163 * for lock request, keep on trying
164 */
165 for (;;) {
166 res = p9_client_lock_dotl(fid, &flock, &status);
167 if (res < 0)
168 goto out_unlock;
169
170 if (status != P9_LOCK_BLOCKED)
171 break;
172 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
173 break;
174 if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
175 != 0)
176 break;
177 /*
178 * p9_client_lock_dotl overwrites flock.client_id with the
179 * server message, free and reuse the client name
180 */
181 if (flock.client_id != fid->clnt->name) {
182 kfree(flock.client_id);
183 flock.client_id = fid->clnt->name;
184 }
185 }
186
187 /* map 9p status to VFS status */
188 switch (status) {
189 case P9_LOCK_SUCCESS:
190 res = 0;
191 break;
192 case P9_LOCK_BLOCKED:
193 res = -EAGAIN;
194 break;
195 default:
196 WARN_ONCE(1, "unknown lock status code: %d\n", status);
197 fallthrough;
198 case P9_LOCK_ERROR:
199 case P9_LOCK_GRACE:
200 res = -ENOLCK;
201 break;
202 }
203
204 out_unlock:
205 /*
206 * incase server returned error for lock request, revert
207 * it locally
208 */
209 if (res < 0 && fl->c.flc_type != F_UNLCK) {
210 unsigned char type = fl->c.flc_type;
211
212 fl->c.flc_type = F_UNLCK;
213 /* Even if this fails we want to return the remote error */
214 locks_lock_file_wait(filp, fl);
215 fl->c.flc_type = type;
216 }
217 if (flock.client_id != fid->clnt->name)
218 kfree(flock.client_id);
219 out:
220 return res;
221 }
222
223 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
224 {
225 struct p9_getlock glock;
226 struct p9_fid *fid;
227 int res = 0;
228
229 fid = filp->private_data;
230 BUG_ON(fid == NULL);
231
232 posix_test_lock(filp, fl);
233 /*
234 * if we have a conflicting lock locally, no need to validate
235 * with server
236 */
237 if (fl->c.flc_type != F_UNLCK)
238 return res;
239
240 /* convert posix lock to p9 tgetlock args */
241 memset(&glock, 0, sizeof(glock));
242 glock.type = P9_LOCK_TYPE_UNLCK;
243 glock.start = fl->fl_start;
244 if (fl->fl_end == OFFSET_MAX)
245 glock.length = 0;
246 else
247 glock.length = fl->fl_end - fl->fl_start + 1;
248 glock.proc_id = fl->c.flc_pid;
249 glock.client_id = fid->clnt->name;
250
251 res = p9_client_getlock_dotl(fid, &glock);
252 if (res < 0)
253 goto out;
254 /* map 9p lock type to os lock type */
255 switch (glock.type) {
256 case P9_LOCK_TYPE_RDLCK:
257 fl->c.flc_type = F_RDLCK;
258 break;
259 case P9_LOCK_TYPE_WRLCK:
260 fl->c.flc_type = F_WRLCK;
261 break;
262 case P9_LOCK_TYPE_UNLCK:
263 fl->c.flc_type = F_UNLCK;
264 break;
265 }
266 if (glock.type != P9_LOCK_TYPE_UNLCK) {
267 fl->fl_start = glock.start;
268 if (glock.length == 0)
269 fl->fl_end = OFFSET_MAX;
270 else
271 fl->fl_end = glock.start + glock.length - 1;
272 fl->c.flc_pid = -glock.proc_id;
273 }
274 out:
275 if (glock.client_id != fid->clnt->name)
276 kfree(glock.client_id);
277 return res;
278 }
279
280 /**
281 * v9fs_file_lock_dotl - lock a file (or directory)
282 * @filp: file to be locked
283 * @cmd: lock command
284 * @fl: file lock structure
285 *
286 */
287
288 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
289 {
290 struct inode *inode = file_inode(filp);
291 int ret = -ENOLCK;
292
293 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
294 filp, cmd, fl, filp);
295
296 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
297 filemap_write_and_wait(inode->i_mapping);
298 invalidate_mapping_pages(&inode->i_data, 0, -1);
299 }
300
301 if (IS_SETLK(cmd) || IS_SETLKW(cmd))
302 ret = v9fs_file_do_lock(filp, cmd, fl);
303 else if (IS_GETLK(cmd))
304 ret = v9fs_file_getlock(filp, fl);
305 else
306 ret = -EINVAL;
307 return ret;
308 }
309
310 /**
311 * v9fs_file_flock_dotl - lock a file
312 * @filp: file to be locked
313 * @cmd: lock command
314 * @fl: file lock structure
315 *
316 */
317
318 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
319 struct file_lock *fl)
320 {
321 struct inode *inode = file_inode(filp);
322 int ret = -ENOLCK;
323
324 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
325 filp, cmd, fl, filp);
326
327 if (!(fl->c.flc_flags & FL_FLOCK))
328 goto out_err;
329
330 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
331 filemap_write_and_wait(inode->i_mapping);
332 invalidate_mapping_pages(&inode->i_data, 0, -1);
333 }
334 /* Convert flock to posix lock */
335 fl->c.flc_flags |= FL_POSIX;
336 fl->c.flc_flags ^= FL_FLOCK;
337
338 if (IS_SETLK(cmd) | IS_SETLKW(cmd))
339 ret = v9fs_file_do_lock(filp, cmd, fl);
340 else
341 ret = -EINVAL;
342 out_err:
343 return ret;
344 }
345
346 /**
347 * v9fs_file_read_iter - read from a file
348 * @iocb: The operation parameters
349 * @to: The buffer to read into
350 *
351 */
352 static ssize_t
353 v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
354 {
355 struct p9_fid *fid = iocb->ki_filp->private_data;
356
357 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
358 fid->fid, iov_iter_count(to), iocb->ki_pos);
359
360 if (fid->mode & P9L_DIRECT)
361 return netfs_unbuffered_read_iter(iocb, to);
362
363 p9_debug(P9_DEBUG_VFS, "(cached)\n");
364 return netfs_file_read_iter(iocb, to);
365 }
366
367 /*
368 * v9fs_file_splice_read - splice-read from a file
369 * @in: The 9p file to read from
370 * @ppos: Where to find/update the file position
371 * @pipe: The pipe to splice into
372 * @len: The maximum amount of data to splice
373 * @flags: SPLICE_F_* flags
374 */
375 static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,
376 struct pipe_inode_info *pipe,
377 size_t len, unsigned int flags)
378 {
379 struct p9_fid *fid = in->private_data;
380
381 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
382 fid->fid, len, *ppos);
383
384 if (fid->mode & P9L_DIRECT)
385 return copy_splice_read(in, ppos, pipe, len, flags);
386 return filemap_splice_read(in, ppos, pipe, len, flags);
387 }
388
389 /**
390 * v9fs_file_write_iter - write to a file
391 * @iocb: The operation parameters
392 * @from: The data to write
393 *
394 */
395 static ssize_t
396 v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
397 {
398 struct file *file = iocb->ki_filp;
399 struct p9_fid *fid = file->private_data;
400
401 p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);
402
403 if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))
404 return netfs_unbuffered_write_iter(iocb, from);
405
406 p9_debug(P9_DEBUG_CACHE, "(cached)\n");
407 return netfs_file_write_iter(iocb, from);
408 }
409
410 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
411 int datasync)
412 {
413 struct p9_fid *fid;
414 struct inode *inode = filp->f_mapping->host;
415 struct p9_wstat wstat;
416 int retval;
417
418 retval = file_write_and_wait_range(filp, start, end);
419 if (retval)
420 return retval;
421
422 inode_lock(inode);
423 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
424
425 fid = filp->private_data;
426 v9fs_blank_wstat(&wstat);
427
428 retval = p9_client_wstat(fid, &wstat);
429 inode_unlock(inode);
430
431 return retval;
432 }
433
434 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
435 int datasync)
436 {
437 struct p9_fid *fid;
438 struct inode *inode = filp->f_mapping->host;
439 int retval;
440
441 retval = file_write_and_wait_range(filp, start, end);
442 if (retval)
443 return retval;
444
445 inode_lock(inode);
446 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
447
448 fid = filp->private_data;
449
450 retval = p9_client_fsync(fid, datasync);
451 inode_unlock(inode);
452
453 return retval;
454 }
455
456 static int
457 v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
458 {
459 int retval;
460 struct inode *inode = file_inode(filp);
461 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
462
463 p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);
464
465 if (!(v9ses->cache & CACHE_WRITEBACK)) {
466 p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
467 return generic_file_readonly_mmap(filp, vma);
468 }
469
470 retval = generic_file_mmap(filp, vma);
471 if (!retval)
472 vma->vm_ops = &v9fs_mmap_file_vm_ops;
473
474 return retval;
475 }
476
477 static vm_fault_t
478 v9fs_vm_page_mkwrite(struct vm_fault *vmf)
479 {
480 return netfs_page_mkwrite(vmf, NULL);
481 }
482
483 static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
484 {
485 struct inode *inode;
486
487 struct writeback_control wbc = {
488 .nr_to_write = LONG_MAX,
489 .sync_mode = WB_SYNC_ALL,
490 .range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
491 /* absolute end, byte at end included */
492 .range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
493 (vma->vm_end - vma->vm_start - 1),
494 };
495
496 if (!(vma->vm_flags & VM_SHARED))
497 return;
498
499 p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
500
501 inode = file_inode(vma->vm_file);
502 filemap_fdatawrite_wbc(inode->i_mapping, &wbc);
503 }
504
505 static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
506 .close = v9fs_mmap_vm_close,
507 .fault = filemap_fault,
508 .map_pages = filemap_map_pages,
509 .page_mkwrite = v9fs_vm_page_mkwrite,
510 };
511
512 const struct file_operations v9fs_file_operations = {
513 .llseek = generic_file_llseek,
514 .read_iter = v9fs_file_read_iter,
515 .write_iter = v9fs_file_write_iter,
516 .open = v9fs_file_open,
517 .release = v9fs_dir_release,
518 .lock = v9fs_file_lock,
519 .mmap = generic_file_readonly_mmap,
520 .splice_read = v9fs_file_splice_read,
521 .splice_write = iter_file_splice_write,
522 .fsync = v9fs_file_fsync,
523 .setlease = simple_nosetlease,
524 };
525
526 const struct file_operations v9fs_file_operations_dotl = {
527 .llseek = generic_file_llseek,
528 .read_iter = v9fs_file_read_iter,
529 .write_iter = v9fs_file_write_iter,
530 .open = v9fs_file_open,
531 .release = v9fs_dir_release,
532 .lock = v9fs_file_lock_dotl,
533 .flock = v9fs_file_flock_dotl,
534 .mmap = v9fs_file_mmap,
535 .splice_read = v9fs_file_splice_read,
536 .splice_write = iter_file_splice_write,
537 .fsync = v9fs_file_fsync_dotl,
538 .setlease = simple_nosetlease,
539 };
540
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