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
31static 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
40int 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 int o_append;
47
48 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
49 v9ses = v9fs_inode2v9ses(inode);
50 if (v9fs_proto_dotl(v9ses)) {
51 omode = v9fs_open_to_dotl_flags(flags: file->f_flags);
52 o_append = P9_DOTL_APPEND;
53 } else {
54 omode = v9fs_uflags2omode(uflags: file->f_flags,
55 extended: v9fs_proto_dotu(v9ses));
56 o_append = P9_OAPPEND;
57 }
58 fid = file->private_data;
59 if (!fid) {
60 fid = v9fs_fid_clone(dentry: file_dentry(file));
61 if (IS_ERR(ptr: fid))
62 return PTR_ERR(ptr: fid);
63
64 if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {
65 int writeback_omode = (omode & ~(P9_OWRITE | o_append)) | P9_ORDWR;
66
67 p9_debug(P9_DEBUG_CACHE, "write-only file with writeback enabled, try opening O_RDWR\n");
68
69 err = p9_client_open(fid, mode: writeback_omode);
70 if (err < 0) {
71 p9_debug(P9_DEBUG_CACHE, "could not open O_RDWR, disabling caches\n");
72 err = p9_client_open(fid, mode: omode);
73 fid->mode |= P9L_DIRECT;
74 }
75 } else {
76 err = p9_client_open(fid, mode: omode);
77 }
78 if (err < 0) {
79 p9_fid_put(fid);
80 return err;
81 }
82 if ((file->f_flags & O_APPEND) &&
83 (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
84 generic_file_llseek(file, offset: 0, SEEK_END);
85
86 file->private_data = fid;
87 }
88
89#ifdef CONFIG_9P_FSCACHE
90 if (v9ses->cache & CACHE_FSCACHE)
91 fscache_use_cookie(cookie: v9fs_inode_cookie(v9inode: V9FS_I(inode)),
92 will_modify: file->f_mode & FMODE_WRITE);
93#endif
94 v9fs_fid_add_modes(fid, s_flags: v9ses->flags, s_cache: v9ses->cache, f_flags: file->f_flags);
95 v9fs_open_fid_add(inode, fid: &fid);
96 return 0;
97}
98
99/**
100 * v9fs_file_lock - lock a file (or directory)
101 * @filp: file to be locked
102 * @cmd: lock command
103 * @fl: file lock structure
104 *
105 * Bugs: this looks like a local only lock, we should extend into 9P
106 * by using open exclusive
107 */
108
109static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
110{
111 struct inode *inode = file_inode(f: filp);
112
113 p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
114
115 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
116 filemap_write_and_wait(mapping: inode->i_mapping);
117 invalidate_mapping_pages(mapping: &inode->i_data, start: 0, end: -1);
118 }
119
120 return 0;
121}
122
123static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
124{
125 struct p9_flock flock;
126 struct p9_fid *fid;
127 uint8_t status = P9_LOCK_ERROR;
128 int res = 0;
129 struct v9fs_session_info *v9ses;
130
131 fid = filp->private_data;
132 BUG_ON(fid == NULL);
133
134 BUG_ON((fl->c.flc_flags & FL_POSIX) != FL_POSIX);
135
136 res = locks_lock_file_wait(filp, fl);
137 if (res < 0)
138 goto out;
139
140 /* convert posix lock to p9 tlock args */
141 memset(&flock, 0, sizeof(flock));
142 /* map the lock type */
143 switch (fl->c.flc_type) {
144 case F_RDLCK:
145 flock.type = P9_LOCK_TYPE_RDLCK;
146 break;
147 case F_WRLCK:
148 flock.type = P9_LOCK_TYPE_WRLCK;
149 break;
150 case F_UNLCK:
151 flock.type = P9_LOCK_TYPE_UNLCK;
152 break;
153 }
154 flock.start = fl->fl_start;
155 if (fl->fl_end == OFFSET_MAX)
156 flock.length = 0;
157 else
158 flock.length = fl->fl_end - fl->fl_start + 1;
159 flock.proc_id = fl->c.flc_pid;
160 flock.client_id = fid->clnt->name;
161 if (IS_SETLKW(cmd))
162 flock.flags = P9_LOCK_FLAGS_BLOCK;
163
164 v9ses = v9fs_inode2v9ses(inode: file_inode(f: filp));
165
166 /*
167 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
168 * for lock request, keep on trying
169 */
170 for (;;) {
171 res = p9_client_lock_dotl(fid, flock: &flock, status: &status);
172 if (res < 0)
173 goto out_unlock;
174
175 if (status != P9_LOCK_BLOCKED)
176 break;
177 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
178 break;
179 if (schedule_timeout_interruptible(timeout: v9ses->session_lock_timeout)
180 != 0)
181 break;
182 /*
183 * p9_client_lock_dotl overwrites flock.client_id with the
184 * server message, free and reuse the client name
185 */
186 if (flock.client_id != fid->clnt->name) {
187 kfree(objp: flock.client_id);
188 flock.client_id = fid->clnt->name;
189 }
190 }
191
192 /* map 9p status to VFS status */
193 switch (status) {
194 case P9_LOCK_SUCCESS:
195 res = 0;
196 break;
197 case P9_LOCK_BLOCKED:
198 res = -EAGAIN;
199 break;
200 default:
201 WARN_ONCE(1, "unknown lock status code: %d\n", status);
202 fallthrough;
203 case P9_LOCK_ERROR:
204 case P9_LOCK_GRACE:
205 res = -ENOLCK;
206 break;
207 }
208
209out_unlock:
210 /*
211 * incase server returned error for lock request, revert
212 * it locally
213 */
214 if (res < 0 && fl->c.flc_type != F_UNLCK) {
215 unsigned char type = fl->c.flc_type;
216
217 fl->c.flc_type = F_UNLCK;
218 /* Even if this fails we want to return the remote error */
219 locks_lock_file_wait(filp, fl);
220 fl->c.flc_type = type;
221 }
222 if (flock.client_id != fid->clnt->name)
223 kfree(objp: flock.client_id);
224out:
225 return res;
226}
227
228static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
229{
230 struct p9_getlock glock;
231 struct p9_fid *fid;
232 int res = 0;
233
234 fid = filp->private_data;
235 BUG_ON(fid == NULL);
236
237 posix_test_lock(filp, fl);
238 /*
239 * if we have a conflicting lock locally, no need to validate
240 * with server
241 */
242 if (fl->c.flc_type != F_UNLCK)
243 return res;
244
245 /* convert posix lock to p9 tgetlock args */
246 memset(&glock, 0, sizeof(glock));
247 glock.type = P9_LOCK_TYPE_UNLCK;
248 glock.start = fl->fl_start;
249 if (fl->fl_end == OFFSET_MAX)
250 glock.length = 0;
251 else
252 glock.length = fl->fl_end - fl->fl_start + 1;
253 glock.proc_id = fl->c.flc_pid;
254 glock.client_id = fid->clnt->name;
255
256 res = p9_client_getlock_dotl(fid, fl: &glock);
257 if (res < 0)
258 goto out;
259 /* map 9p lock type to os lock type */
260 switch (glock.type) {
261 case P9_LOCK_TYPE_RDLCK:
262 fl->c.flc_type = F_RDLCK;
263 break;
264 case P9_LOCK_TYPE_WRLCK:
265 fl->c.flc_type = F_WRLCK;
266 break;
267 case P9_LOCK_TYPE_UNLCK:
268 fl->c.flc_type = F_UNLCK;
269 break;
270 }
271 if (glock.type != P9_LOCK_TYPE_UNLCK) {
272 fl->fl_start = glock.start;
273 if (glock.length == 0)
274 fl->fl_end = OFFSET_MAX;
275 else
276 fl->fl_end = glock.start + glock.length - 1;
277 fl->c.flc_pid = -glock.proc_id;
278 }
279out:
280 if (glock.client_id != fid->clnt->name)
281 kfree(objp: glock.client_id);
282 return res;
283}
284
285/**
286 * v9fs_file_lock_dotl - lock a file (or directory)
287 * @filp: file to be locked
288 * @cmd: lock command
289 * @fl: file lock structure
290 *
291 */
292
293static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
294{
295 struct inode *inode = file_inode(f: filp);
296 int ret = -ENOLCK;
297
298 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
299 filp, cmd, fl, filp);
300
301 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
302 filemap_write_and_wait(mapping: inode->i_mapping);
303 invalidate_mapping_pages(mapping: &inode->i_data, start: 0, end: -1);
304 }
305
306 if (IS_SETLK(cmd) || IS_SETLKW(cmd))
307 ret = v9fs_file_do_lock(filp, cmd, fl);
308 else if (IS_GETLK(cmd))
309 ret = v9fs_file_getlock(filp, fl);
310 else
311 ret = -EINVAL;
312 return ret;
313}
314
315/**
316 * v9fs_file_flock_dotl - lock a file
317 * @filp: file to be locked
318 * @cmd: lock command
319 * @fl: file lock structure
320 *
321 */
322
323static int v9fs_file_flock_dotl(struct file *filp, int cmd,
324 struct file_lock *fl)
325{
326 struct inode *inode = file_inode(f: filp);
327 int ret = -ENOLCK;
328
329 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
330 filp, cmd, fl, filp);
331
332 if (!(fl->c.flc_flags & FL_FLOCK))
333 goto out_err;
334
335 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->c.flc_type != F_UNLCK) {
336 filemap_write_and_wait(mapping: inode->i_mapping);
337 invalidate_mapping_pages(mapping: &inode->i_data, start: 0, end: -1);
338 }
339 /* Convert flock to posix lock */
340 fl->c.flc_flags |= FL_POSIX;
341 fl->c.flc_flags ^= FL_FLOCK;
342
343 if (IS_SETLK(cmd) | IS_SETLKW(cmd))
344 ret = v9fs_file_do_lock(filp, cmd, fl);
345 else
346 ret = -EINVAL;
347out_err:
348 return ret;
349}
350
351/**
352 * v9fs_file_read_iter - read from a file
353 * @iocb: The operation parameters
354 * @to: The buffer to read into
355 *
356 */
357static ssize_t
358v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
359{
360 struct p9_fid *fid = iocb->ki_filp->private_data;
361
362 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
363 fid->fid, iov_iter_count(to), iocb->ki_pos);
364
365 if (fid->mode & P9L_DIRECT)
366 return netfs_unbuffered_read_iter(iocb, iter: to);
367
368 p9_debug(P9_DEBUG_VFS, "(cached)\n");
369 return netfs_file_read_iter(iocb, iter: to);
370}
371
372/*
373 * v9fs_file_splice_read - splice-read from a file
374 * @in: The 9p file to read from
375 * @ppos: Where to find/update the file position
376 * @pipe: The pipe to splice into
377 * @len: The maximum amount of data to splice
378 * @flags: SPLICE_F_* flags
379 */
380static ssize_t v9fs_file_splice_read(struct file *in, loff_t *ppos,
381 struct pipe_inode_info *pipe,
382 size_t len, unsigned int flags)
383{
384 struct p9_fid *fid = in->private_data;
385
386 p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
387 fid->fid, len, *ppos);
388
389 if (fid->mode & P9L_DIRECT)
390 return copy_splice_read(in, ppos, pipe, len, flags);
391 return filemap_splice_read(in, ppos, pipe, len, flags);
392}
393
394/**
395 * v9fs_file_write_iter - write to a file
396 * @iocb: The operation parameters
397 * @from: The data to write
398 *
399 */
400static ssize_t
401v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
402{
403 struct file *file = iocb->ki_filp;
404 struct p9_fid *fid = file->private_data;
405
406 p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);
407
408 if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))
409 return netfs_unbuffered_write_iter(iocb, from);
410
411 p9_debug(P9_DEBUG_CACHE, "(cached)\n");
412 return netfs_file_write_iter(iocb, from);
413}
414
415static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
416 int datasync)
417{
418 struct p9_fid *fid;
419 struct inode *inode = filp->f_mapping->host;
420 struct p9_wstat wstat;
421 int retval;
422
423 retval = file_write_and_wait_range(file: filp, start, end);
424 if (retval)
425 return retval;
426
427 inode_lock(inode);
428 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
429
430 fid = filp->private_data;
431 v9fs_blank_wstat(wstat: &wstat);
432
433 retval = p9_client_wstat(fid, wst: &wstat);
434 inode_unlock(inode);
435
436 return retval;
437}
438
439int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
440 int datasync)
441{
442 struct p9_fid *fid;
443 struct inode *inode = filp->f_mapping->host;
444 int retval;
445
446 retval = file_write_and_wait_range(file: filp, start, end);
447 if (retval)
448 return retval;
449
450 inode_lock(inode);
451 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
452
453 fid = filp->private_data;
454
455 retval = p9_client_fsync(fid, datasync);
456 inode_unlock(inode);
457
458 return retval;
459}
460
461static int
462v9fs_file_mmap_prepare(struct vm_area_desc *desc)
463{
464 int retval;
465 struct file *filp = desc->file;
466 struct inode *inode = file_inode(f: filp);
467 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
468
469 p9_debug(P9_DEBUG_MMAP, "filp :%p\n", filp);
470
471 if (!(v9ses->cache & CACHE_WRITEBACK)) {
472 p9_debug(P9_DEBUG_CACHE, "(read-only mmap mode)");
473 return generic_file_readonly_mmap_prepare(desc);
474 }
475
476 retval = generic_file_mmap_prepare(desc);
477 if (!retval)
478 desc->vm_ops = &v9fs_mmap_file_vm_ops;
479
480 return retval;
481}
482
483static vm_fault_t
484v9fs_vm_page_mkwrite(struct vm_fault *vmf)
485{
486 return netfs_page_mkwrite(vmf, NULL);
487}
488
489static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
490{
491 if (!(vma->vm_flags & VM_SHARED))
492 return;
493
494 p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
495
496 filemap_fdatawrite_range(mapping: file_inode(f: vma->vm_file)->i_mapping,
497 start: (loff_t)vma->vm_pgoff * PAGE_SIZE,
498 end: (loff_t)vma->vm_pgoff * PAGE_SIZE +
499 (vma->vm_end - vma->vm_start - 1));
500}
501
502static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
503 .close = v9fs_mmap_vm_close,
504 .fault = filemap_fault,
505 .map_pages = filemap_map_pages,
506 .page_mkwrite = v9fs_vm_page_mkwrite,
507};
508
509const struct file_operations v9fs_file_operations = {
510 .llseek = generic_file_llseek,
511 .read_iter = v9fs_file_read_iter,
512 .write_iter = v9fs_file_write_iter,
513 .open = v9fs_file_open,
514 .release = v9fs_dir_release,
515 .lock = v9fs_file_lock,
516 .mmap_prepare = generic_file_readonly_mmap_prepare,
517 .splice_read = v9fs_file_splice_read,
518 .splice_write = iter_file_splice_write,
519 .fsync = v9fs_file_fsync,
520 .setlease = simple_nosetlease,
521};
522
523const struct file_operations v9fs_file_operations_dotl = {
524 .llseek = generic_file_llseek,
525 .read_iter = v9fs_file_read_iter,
526 .write_iter = v9fs_file_write_iter,
527 .open = v9fs_file_open,
528 .release = v9fs_dir_release,
529 .lock = v9fs_file_lock_dotl,
530 .flock = v9fs_file_flock_dotl,
531 .mmap_prepare = v9fs_file_mmap_prepare,
532 .splice_read = v9fs_file_splice_read,
533 .splice_write = iter_file_splice_write,
534 .fsync = v9fs_file_fsync_dotl,
535 .setlease = simple_nosetlease,
536};
537

source code of linux/fs/9p/vfs_file.c