1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * This file contains vfs inode ops for the 9P2000 protocol.
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/file.h>
15 #include <linux/pagemap.h>
16 #include <linux/stat.h>
17 #include <linux/string.h>
18 #include <linux/namei.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/xattr.h>
22 #include <linux/posix_acl.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 #include "xattr.h"
31 #include "acl.h"
32
33 static const struct inode_operations v9fs_dir_inode_operations;
34 static const struct inode_operations v9fs_dir_inode_operations_dotu;
35 static const struct inode_operations v9fs_file_inode_operations;
36 static const struct inode_operations v9fs_symlink_inode_operations;
37
38 /**
39 * unixmode2p9mode - convert unix mode bits to plan 9
40 * @v9ses: v9fs session information
41 * @mode: mode to convert
42 *
43 */
44
45 static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
46 {
47 int res;
48
49 res = mode & 0777;
50 if (S_ISDIR(mode))
51 res |= P9_DMDIR;
52 if (v9fs_proto_dotu(v9ses)) {
53 if (v9ses->nodev == 0) {
54 if (S_ISSOCK(mode))
55 res |= P9_DMSOCKET;
56 if (S_ISFIFO(mode))
57 res |= P9_DMNAMEDPIPE;
58 if (S_ISBLK(mode))
59 res |= P9_DMDEVICE;
60 if (S_ISCHR(mode))
61 res |= P9_DMDEVICE;
62 }
63
64 if ((mode & S_ISUID) == S_ISUID)
65 res |= P9_DMSETUID;
66 if ((mode & S_ISGID) == S_ISGID)
67 res |= P9_DMSETGID;
68 if ((mode & S_ISVTX) == S_ISVTX)
69 res |= P9_DMSETVTX;
70 }
71 return res;
72 }
73
74 /**
75 * p9mode2perm- convert plan9 mode bits to unix permission bits
76 * @v9ses: v9fs session information
77 * @stat: p9_wstat from which mode need to be derived
78 *
79 */
80 static int p9mode2perm(struct v9fs_session_info *v9ses,
81 struct p9_wstat *stat)
82 {
83 int res;
84 int mode = stat->mode;
85
86 res = mode & 0777; /* S_IRWXUGO */
87 if (v9fs_proto_dotu(v9ses)) {
88 if ((mode & P9_DMSETUID) == P9_DMSETUID)
89 res |= S_ISUID;
90
91 if ((mode & P9_DMSETGID) == P9_DMSETGID)
92 res |= S_ISGID;
93
94 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
95 res |= S_ISVTX;
96 }
97 return res;
98 }
99
100 /**
101 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
102 * @v9ses: v9fs session information
103 * @stat: p9_wstat from which mode need to be derived
104 * @rdev: major number, minor number in case of device files.
105 *
106 */
107 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
108 struct p9_wstat *stat, dev_t *rdev)
109 {
110 int res, r;
111 u32 mode = stat->mode;
112
113 *rdev = 0;
114 res = p9mode2perm(v9ses, stat);
115
116 if ((mode & P9_DMDIR) == P9_DMDIR)
117 res |= S_IFDIR;
118 else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
119 res |= S_IFLNK;
120 else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
121 && (v9ses->nodev == 0))
122 res |= S_IFSOCK;
123 else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
124 && (v9ses->nodev == 0))
125 res |= S_IFIFO;
126 else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
127 && (v9ses->nodev == 0)) {
128 char type = 0;
129 int major = -1, minor = -1;
130
131 r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
132 if (r != 3) {
133 p9_debug(P9_DEBUG_ERROR,
134 "invalid device string, umode will be bogus: %s\n",
135 stat->extension);
136 return res;
137 }
138 switch (type) {
139 case 'c':
140 res |= S_IFCHR;
141 break;
142 case 'b':
143 res |= S_IFBLK;
144 break;
145 default:
146 p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
147 type, stat->extension);
148 }
149 *rdev = MKDEV(major, minor);
150 } else
151 res |= S_IFREG;
152
153 return res;
154 }
155
156 /**
157 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
158 * @uflags: flags to convert
159 * @extended: if .u extensions are active
160 */
161
162 int v9fs_uflags2omode(int uflags, int extended)
163 {
164 int ret;
165
166 switch (uflags&3) {
167 default:
168 case O_RDONLY:
169 ret = P9_OREAD;
170 break;
171
172 case O_WRONLY:
173 ret = P9_OWRITE;
174 break;
175
176 case O_RDWR:
177 ret = P9_ORDWR;
178 break;
179 }
180
181 if (uflags & O_TRUNC)
182 ret |= P9_OTRUNC;
183
184 if (extended) {
185 if (uflags & O_EXCL)
186 ret |= P9_OEXCL;
187
188 if (uflags & O_APPEND)
189 ret |= P9_OAPPEND;
190 }
191
192 return ret;
193 }
194
195 /**
196 * v9fs_blank_wstat - helper function to setup a 9P stat structure
197 * @wstat: structure to initialize
198 *
199 */
200
201 void
202 v9fs_blank_wstat(struct p9_wstat *wstat)
203 {
204 wstat->type = ~0;
205 wstat->dev = ~0;
206 wstat->qid.type = ~0;
207 wstat->qid.version = ~0;
208 *((long long *)&wstat->qid.path) = ~0;
209 wstat->mode = ~0;
210 wstat->atime = ~0;
211 wstat->mtime = ~0;
212 wstat->length = ~0;
213 wstat->name = NULL;
214 wstat->uid = NULL;
215 wstat->gid = NULL;
216 wstat->muid = NULL;
217 wstat->n_uid = INVALID_UID;
218 wstat->n_gid = INVALID_GID;
219 wstat->n_muid = INVALID_UID;
220 wstat->extension = NULL;
221 }
222
223 /**
224 * v9fs_alloc_inode - helper function to allocate an inode
225 * @sb: The superblock to allocate the inode from
226 */
227 struct inode *v9fs_alloc_inode(struct super_block *sb)
228 {
229 struct v9fs_inode *v9inode;
230
231 v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
232 if (!v9inode)
233 return NULL;
234 v9inode->cache_validity = 0;
235 mutex_init(&v9inode->v_mutex);
236 return &v9inode->netfs.inode;
237 }
238
239 /**
240 * v9fs_free_inode - destroy an inode
241 * @inode: The inode to be freed
242 */
243
244 void v9fs_free_inode(struct inode *inode)
245 {
246 kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
247 }
248
249 /*
250 * Set parameters for the netfs library
251 */
252 void v9fs_set_netfs_context(struct inode *inode)
253 {
254 struct v9fs_inode *v9inode = V9FS_I(inode);
255 netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
256 }
257
258 int v9fs_init_inode(struct v9fs_session_info *v9ses,
259 struct inode *inode, struct p9_qid *qid, umode_t mode, dev_t rdev)
260 {
261 int err = 0;
262 struct v9fs_inode *v9inode = V9FS_I(inode);
263
264 memcpy(&v9inode->qid, qid, sizeof(struct p9_qid));
265
266 inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
267 inode->i_blocks = 0;
268 inode->i_rdev = rdev;
269 simple_inode_init_ts(inode);
270 inode->i_mapping->a_ops = &v9fs_addr_operations;
271 inode->i_private = NULL;
272
273 switch (mode & S_IFMT) {
274 case S_IFIFO:
275 case S_IFBLK:
276 case S_IFCHR:
277 case S_IFSOCK:
278 if (v9fs_proto_dotl(v9ses)) {
279 inode->i_op = &v9fs_file_inode_operations_dotl;
280 } else if (v9fs_proto_dotu(v9ses)) {
281 inode->i_op = &v9fs_file_inode_operations;
282 } else {
283 p9_debug(P9_DEBUG_ERROR,
284 "special files without extended mode\n");
285 err = -EINVAL;
286 goto error;
287 }
288 init_special_inode(inode, inode->i_mode, inode->i_rdev);
289 break;
290 case S_IFREG:
291 if (v9fs_proto_dotl(v9ses)) {
292 inode->i_op = &v9fs_file_inode_operations_dotl;
293 inode->i_fop = &v9fs_file_operations_dotl;
294 } else {
295 inode->i_op = &v9fs_file_inode_operations;
296 inode->i_fop = &v9fs_file_operations;
297 }
298
299 break;
300 case S_IFLNK:
301 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
302 p9_debug(P9_DEBUG_ERROR,
303 "extended modes used with legacy protocol\n");
304 err = -EINVAL;
305 goto error;
306 }
307
308 if (v9fs_proto_dotl(v9ses))
309 inode->i_op = &v9fs_symlink_inode_operations_dotl;
310 else
311 inode->i_op = &v9fs_symlink_inode_operations;
312
313 break;
314 case S_IFDIR:
315 inc_nlink(inode);
316 if (v9fs_proto_dotl(v9ses))
317 inode->i_op = &v9fs_dir_inode_operations_dotl;
318 else if (v9fs_proto_dotu(v9ses))
319 inode->i_op = &v9fs_dir_inode_operations_dotu;
320 else
321 inode->i_op = &v9fs_dir_inode_operations;
322
323 if (v9fs_proto_dotl(v9ses))
324 inode->i_fop = &v9fs_dir_operations_dotl;
325 else
326 inode->i_fop = &v9fs_dir_operations;
327
328 break;
329 default:
330 p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
331 mode, mode & S_IFMT);
332 err = -EINVAL;
333 goto error;
334 }
335 error:
336 return err;
337
338 }
339
340 /**
341 * v9fs_evict_inode - Remove an inode from the inode cache
342 * @inode: inode to release
343 *
344 */
345 void v9fs_evict_inode(struct inode *inode)
346 {
347 struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
348 __le32 __maybe_unused version;
349
350 if (!is_bad_inode(inode)) {
351 netfs_wait_for_outstanding_io(inode);
352 truncate_inode_pages_final(&inode->i_data);
353
354 version = cpu_to_le32(v9inode->qid.version);
355 netfs_clear_inode_writeback(inode, &version);
356
357 clear_inode(inode);
358 filemap_fdatawrite(&inode->i_data);
359
360 #ifdef CONFIG_9P_FSCACHE
361 if (v9fs_inode_cookie(v9inode))
362 fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
363 #endif
364 } else
365 clear_inode(inode);
366 }
367
368 struct inode *
369 v9fs_fid_iget(struct super_block *sb, struct p9_fid *fid, bool new)
370 {
371 dev_t rdev;
372 int retval;
373 umode_t umode;
374 struct inode *inode;
375 struct p9_wstat *st;
376 struct v9fs_session_info *v9ses = sb->s_fs_info;
377
378 inode = iget_locked(sb, QID2INO(&fid->qid));
379 if (unlikely(!inode))
380 return ERR_PTR(-ENOMEM);
381 if (!(inode->i_state & I_NEW)) {
382 if (!new) {
383 goto done;
384 } else {
385 p9_debug(P9_DEBUG_VFS, "WARNING: Inode collision %ld\n",
386 inode->i_ino);
387 iput(inode);
388 remove_inode_hash(inode);
389 inode = iget_locked(sb, QID2INO(&fid->qid));
390 WARN_ON(!(inode->i_state & I_NEW));
391 }
392 }
393
394 /*
395 * initialize the inode with the stat info
396 * FIXME!! we may need support for stale inodes
397 * later.
398 */
399 st = p9_client_stat(fid);
400 if (IS_ERR(st)) {
401 retval = PTR_ERR(st);
402 goto error;
403 }
404
405 umode = p9mode2unixmode(v9ses, st, &rdev);
406 retval = v9fs_init_inode(v9ses, inode, &fid->qid, umode, rdev);
407 v9fs_stat2inode(st, inode, sb, 0);
408 p9stat_free(st);
409 kfree(st);
410 if (retval)
411 goto error;
412
413 v9fs_set_netfs_context(inode);
414 v9fs_cache_inode_get_cookie(inode);
415 unlock_new_inode(inode);
416 done:
417 return inode;
418 error:
419 iget_failed(inode);
420 return ERR_PTR(retval);
421 }
422
423 /**
424 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
425 * plan 9 AT flag.
426 * @flags: flags to convert
427 */
428 static int v9fs_at_to_dotl_flags(int flags)
429 {
430 int rflags = 0;
431
432 if (flags & AT_REMOVEDIR)
433 rflags |= P9_DOTL_AT_REMOVEDIR;
434
435 return rflags;
436 }
437
438 /**
439 * v9fs_dec_count - helper functon to drop i_nlink.
440 *
441 * If a directory had nlink <= 2 (including . and ..), then we should not drop
442 * the link count, which indicates the underlying exported fs doesn't maintain
443 * nlink accurately. e.g.
444 * - overlayfs sets nlink to 1 for merged dir
445 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
446 * than EXT4_LINK_MAX (65000) links.
447 *
448 * @inode: inode whose nlink is being dropped
449 */
450 static void v9fs_dec_count(struct inode *inode)
451 {
452 if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2) {
453 if (inode->i_nlink) {
454 drop_nlink(inode);
455 } else {
456 p9_debug(P9_DEBUG_VFS,
457 "WARNING: unexpected i_nlink zero %d inode %ld\n",
458 inode->i_nlink, inode->i_ino);
459 }
460 }
461 }
462
463 /**
464 * v9fs_remove - helper function to remove files and directories
465 * @dir: directory inode that is being deleted
466 * @dentry: dentry that is being deleted
467 * @flags: removing a directory
468 *
469 */
470
471 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
472 {
473 struct inode *inode;
474 int retval = -EOPNOTSUPP;
475 struct p9_fid *v9fid, *dfid;
476 struct v9fs_session_info *v9ses;
477
478 p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
479 dir, dentry, flags);
480
481 v9ses = v9fs_inode2v9ses(dir);
482 inode = d_inode(dentry);
483 dfid = v9fs_parent_fid(dentry);
484 if (IS_ERR(dfid)) {
485 retval = PTR_ERR(dfid);
486 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
487 return retval;
488 }
489 if (v9fs_proto_dotl(v9ses))
490 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
491 v9fs_at_to_dotl_flags(flags));
492 p9_fid_put(dfid);
493 if (retval == -EOPNOTSUPP) {
494 /* Try the one based on path */
495 v9fid = v9fs_fid_clone(dentry);
496 if (IS_ERR(v9fid))
497 return PTR_ERR(v9fid);
498 retval = p9_client_remove(v9fid);
499 }
500 if (!retval) {
501 /*
502 * directories on unlink should have zero
503 * link count
504 */
505 if (flags & AT_REMOVEDIR) {
506 clear_nlink(inode);
507 v9fs_dec_count(dir);
508 } else
509 v9fs_dec_count(inode);
510
511 if (inode->i_nlink <= 0) /* no more refs unhash it */
512 remove_inode_hash(inode);
513
514 v9fs_invalidate_inode_attr(inode);
515 v9fs_invalidate_inode_attr(dir);
516
517 /* invalidate all fids associated with dentry */
518 /* NOTE: This will not include open fids */
519 dentry->d_op->d_release(dentry);
520 }
521 return retval;
522 }
523
524 /**
525 * v9fs_create - Create a file
526 * @v9ses: session information
527 * @dir: directory that dentry is being created in
528 * @dentry: dentry that is being created
529 * @extension: 9p2000.u extension string to support devices, etc.
530 * @perm: create permissions
531 * @mode: open mode
532 *
533 */
534 static struct p9_fid *
535 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
536 struct dentry *dentry, char *extension, u32 perm, u8 mode)
537 {
538 int err;
539 const unsigned char *name;
540 struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
541 struct inode *inode;
542
543 p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
544
545 name = dentry->d_name.name;
546 dfid = v9fs_parent_fid(dentry);
547 if (IS_ERR(dfid)) {
548 err = PTR_ERR(dfid);
549 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
550 return ERR_PTR(err);
551 }
552
553 /* clone a fid to use for creation */
554 ofid = clone_fid(dfid);
555 if (IS_ERR(ofid)) {
556 err = PTR_ERR(ofid);
557 p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
558 goto error;
559 }
560
561 err = p9_client_fcreate(ofid, name, perm, mode, extension);
562 if (err < 0) {
563 p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
564 goto error;
565 }
566
567 if (!(perm & P9_DMLINK)) {
568 /* now walk from the parent so we can get unopened fid */
569 fid = p9_client_walk(dfid, 1, &name, 1);
570 if (IS_ERR(fid)) {
571 err = PTR_ERR(fid);
572 p9_debug(P9_DEBUG_VFS,
573 "p9_client_walk failed %d\n", err);
574 goto error;
575 }
576 /*
577 * instantiate inode and assign the unopened fid to the dentry
578 */
579 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb, true);
580 if (IS_ERR(inode)) {
581 err = PTR_ERR(inode);
582 p9_debug(P9_DEBUG_VFS,
583 "inode creation failed %d\n", err);
584 goto error;
585 }
586 v9fs_fid_add(dentry, &fid);
587 d_instantiate(dentry, inode);
588 }
589 p9_fid_put(dfid);
590 return ofid;
591 error:
592 p9_fid_put(dfid);
593 p9_fid_put(ofid);
594 p9_fid_put(fid);
595 return ERR_PTR(err);
596 }
597
598 /**
599 * v9fs_vfs_create - VFS hook to create a regular file
600 * @idmap: idmap of the mount
601 * @dir: The parent directory
602 * @dentry: The name of file to be created
603 * @mode: The UNIX file mode to set
604 * @excl: True if the file must not yet exist
605 *
606 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open(). This is only called
607 * for mknod(2).
608 *
609 */
610
611 static int
612 v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
613 struct dentry *dentry, umode_t mode, bool excl)
614 {
615 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
616 u32 perm = unixmode2p9mode(v9ses, mode);
617 struct p9_fid *fid;
618
619 /* P9_OEXCL? */
620 fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
621 if (IS_ERR(fid))
622 return PTR_ERR(fid);
623
624 v9fs_invalidate_inode_attr(dir);
625 p9_fid_put(fid);
626
627 return 0;
628 }
629
630 /**
631 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
632 * @idmap: idmap of the mount
633 * @dir: inode that is being unlinked
634 * @dentry: dentry that is being unlinked
635 * @mode: mode for new directory
636 *
637 */
638
639 static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
640 struct dentry *dentry, umode_t mode)
641 {
642 int err;
643 u32 perm;
644 struct p9_fid *fid;
645 struct v9fs_session_info *v9ses;
646
647 p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
648 err = 0;
649 v9ses = v9fs_inode2v9ses(dir);
650 perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
651 fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
652 if (IS_ERR(fid)) {
653 err = PTR_ERR(fid);
654 fid = NULL;
655 } else {
656 inc_nlink(dir);
657 v9fs_invalidate_inode_attr(dir);
658 }
659
660 if (fid)
661 p9_fid_put(fid);
662
663 return err;
664 }
665
666 /**
667 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
668 * @dir: inode that is being walked from
669 * @dentry: dentry that is being walked to?
670 * @flags: lookup flags (unused)
671 *
672 */
673
674 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
675 unsigned int flags)
676 {
677 struct dentry *res;
678 struct v9fs_session_info *v9ses;
679 struct p9_fid *dfid, *fid;
680 struct inode *inode;
681 const unsigned char *name;
682
683 p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
684 dir, dentry, dentry, flags);
685
686 if (dentry->d_name.len > NAME_MAX)
687 return ERR_PTR(-ENAMETOOLONG);
688
689 v9ses = v9fs_inode2v9ses(dir);
690 /* We can walk d_parent because we hold the dir->i_mutex */
691 dfid = v9fs_parent_fid(dentry);
692 if (IS_ERR(dfid))
693 return ERR_CAST(dfid);
694
695 /*
696 * Make sure we don't use a wrong inode due to parallel
697 * unlink. For cached mode create calls request for new
698 * inode. But with cache disabled, lookup should do this.
699 */
700 name = dentry->d_name.name;
701 fid = p9_client_walk(dfid, 1, &name, 1);
702 p9_fid_put(dfid);
703 if (fid == ERR_PTR(-ENOENT))
704 inode = NULL;
705 else if (IS_ERR(fid))
706 inode = ERR_CAST(fid);
707 else
708 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb, false);
709 /*
710 * If we had a rename on the server and a parallel lookup
711 * for the new name, then make sure we instantiate with
712 * the new name. ie look up for a/b, while on server somebody
713 * moved b under k and client parallely did a lookup for
714 * k/b.
715 */
716 res = d_splice_alias(inode, dentry);
717 if (!IS_ERR(fid)) {
718 if (!res)
719 v9fs_fid_add(dentry, &fid);
720 else if (!IS_ERR(res))
721 v9fs_fid_add(res, &fid);
722 else
723 p9_fid_put(fid);
724 }
725 return res;
726 }
727
728 static int
729 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
730 struct file *file, unsigned int flags, umode_t mode)
731 {
732 int err;
733 u32 perm;
734 struct v9fs_inode __maybe_unused *v9inode;
735 struct v9fs_session_info *v9ses;
736 struct p9_fid *fid;
737 struct dentry *res = NULL;
738 struct inode *inode;
739 int p9_omode;
740
741 if (d_in_lookup(dentry)) {
742 res = v9fs_vfs_lookup(dir, dentry, 0);
743 if (IS_ERR(res))
744 return PTR_ERR(res);
745
746 if (res)
747 dentry = res;
748 }
749
750 /* Only creates */
751 if (!(flags & O_CREAT) || d_really_is_positive(dentry))
752 return finish_no_open(file, res);
753
754 v9ses = v9fs_inode2v9ses(dir);
755 perm = unixmode2p9mode(v9ses, mode);
756 p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
757
758 if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
759 p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
760 p9_debug(P9_DEBUG_CACHE,
761 "write-only file with writeback enabled, creating w/ O_RDWR\n");
762 }
763 fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
764 if (IS_ERR(fid)) {
765 err = PTR_ERR(fid);
766 goto error;
767 }
768
769 v9fs_invalidate_inode_attr(dir);
770 inode = d_inode(dentry);
771 v9inode = V9FS_I(inode);
772 err = finish_open(file, dentry, generic_file_open);
773 if (err)
774 goto error;
775
776 file->private_data = fid;
777 #ifdef CONFIG_9P_FSCACHE
778 if (v9ses->cache & CACHE_FSCACHE)
779 fscache_use_cookie(v9fs_inode_cookie(v9inode),
780 file->f_mode & FMODE_WRITE);
781 #endif
782
783 v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
784 v9fs_open_fid_add(inode, &fid);
785
786 file->f_mode |= FMODE_CREATED;
787 out:
788 dput(res);
789 return err;
790
791 error:
792 p9_fid_put(fid);
793 goto out;
794 }
795
796 /**
797 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
798 * @i: inode that is being unlinked
799 * @d: dentry that is being unlinked
800 *
801 */
802
803 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
804 {
805 return v9fs_remove(i, d, 0);
806 }
807
808 /**
809 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
810 * @i: inode that is being unlinked
811 * @d: dentry that is being unlinked
812 *
813 */
814
815 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
816 {
817 return v9fs_remove(i, d, AT_REMOVEDIR);
818 }
819
820 /**
821 * v9fs_vfs_rename - VFS hook to rename an inode
822 * @idmap: The idmap of the mount
823 * @old_dir: old dir inode
824 * @old_dentry: old dentry
825 * @new_dir: new dir inode
826 * @new_dentry: new dentry
827 * @flags: RENAME_* flags
828 *
829 */
830
831 int
832 v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
833 struct dentry *old_dentry, struct inode *new_dir,
834 struct dentry *new_dentry, unsigned int flags)
835 {
836 int retval;
837 struct inode *old_inode;
838 struct inode *new_inode;
839 struct v9fs_session_info *v9ses;
840 struct p9_fid *oldfid = NULL, *dfid = NULL;
841 struct p9_fid *olddirfid = NULL;
842 struct p9_fid *newdirfid = NULL;
843 struct p9_wstat wstat;
844
845 if (flags)
846 return -EINVAL;
847
848 p9_debug(P9_DEBUG_VFS, "\n");
849 old_inode = d_inode(old_dentry);
850 new_inode = d_inode(new_dentry);
851 v9ses = v9fs_inode2v9ses(old_inode);
852 oldfid = v9fs_fid_lookup(old_dentry);
853 if (IS_ERR(oldfid))
854 return PTR_ERR(oldfid);
855
856 dfid = v9fs_parent_fid(old_dentry);
857 olddirfid = clone_fid(dfid);
858 p9_fid_put(dfid);
859 dfid = NULL;
860
861 if (IS_ERR(olddirfid)) {
862 retval = PTR_ERR(olddirfid);
863 goto error;
864 }
865
866 dfid = v9fs_parent_fid(new_dentry);
867 newdirfid = clone_fid(dfid);
868 p9_fid_put(dfid);
869 dfid = NULL;
870
871 if (IS_ERR(newdirfid)) {
872 retval = PTR_ERR(newdirfid);
873 goto error;
874 }
875
876 down_write(&v9ses->rename_sem);
877 if (v9fs_proto_dotl(v9ses)) {
878 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
879 newdirfid, new_dentry->d_name.name);
880 if (retval == -EOPNOTSUPP)
881 retval = p9_client_rename(oldfid, newdirfid,
882 new_dentry->d_name.name);
883 if (retval != -EOPNOTSUPP)
884 goto error_locked;
885 }
886 if (old_dentry->d_parent != new_dentry->d_parent) {
887 /*
888 * 9P .u can only handle file rename in the same directory
889 */
890
891 p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
892 retval = -EXDEV;
893 goto error_locked;
894 }
895 v9fs_blank_wstat(&wstat);
896 wstat.muid = v9ses->uname;
897 wstat.name = new_dentry->d_name.name;
898 retval = p9_client_wstat(oldfid, &wstat);
899
900 error_locked:
901 if (!retval) {
902 if (new_inode) {
903 if (S_ISDIR(new_inode->i_mode))
904 clear_nlink(new_inode);
905 else
906 v9fs_dec_count(new_inode);
907 }
908 if (S_ISDIR(old_inode->i_mode)) {
909 if (!new_inode)
910 inc_nlink(new_dir);
911 v9fs_dec_count(old_dir);
912 }
913 v9fs_invalidate_inode_attr(old_inode);
914 v9fs_invalidate_inode_attr(old_dir);
915 v9fs_invalidate_inode_attr(new_dir);
916
917 /* successful rename */
918 d_move(old_dentry, new_dentry);
919 }
920 up_write(&v9ses->rename_sem);
921
922 error:
923 p9_fid_put(newdirfid);
924 p9_fid_put(olddirfid);
925 p9_fid_put(oldfid);
926 return retval;
927 }
928
929 /**
930 * v9fs_vfs_getattr - retrieve file metadata
931 * @idmap: idmap of the mount
932 * @path: Object to query
933 * @stat: metadata structure to populate
934 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
935 * @flags: AT_STATX_xxx setting
936 *
937 */
938
939 static int
940 v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
941 struct kstat *stat, u32 request_mask, unsigned int flags)
942 {
943 struct dentry *dentry = path->dentry;
944 struct inode *inode = d_inode(dentry);
945 struct v9fs_session_info *v9ses;
946 struct p9_fid *fid;
947 struct p9_wstat *st;
948
949 p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
950 v9ses = v9fs_dentry2v9ses(dentry);
951 if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
952 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
953 return 0;
954 } else if (v9ses->cache & CACHE_WRITEBACK) {
955 if (S_ISREG(inode->i_mode)) {
956 int retval = filemap_fdatawrite(inode->i_mapping);
957
958 if (retval)
959 p9_debug(P9_DEBUG_ERROR,
960 "flushing writeback during getattr returned %d\n", retval);
961 }
962 }
963 fid = v9fs_fid_lookup(dentry);
964 if (IS_ERR(fid))
965 return PTR_ERR(fid);
966
967 st = p9_client_stat(fid);
968 p9_fid_put(fid);
969 if (IS_ERR(st))
970 return PTR_ERR(st);
971
972 v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
973 generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
974
975 p9stat_free(st);
976 kfree(st);
977 return 0;
978 }
979
980 /**
981 * v9fs_vfs_setattr - set file metadata
982 * @idmap: idmap of the mount
983 * @dentry: file whose metadata to set
984 * @iattr: metadata assignment structure
985 *
986 */
987
988 static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
989 struct dentry *dentry, struct iattr *iattr)
990 {
991 int retval, use_dentry = 0;
992 struct inode *inode = d_inode(dentry);
993 struct v9fs_session_info *v9ses;
994 struct p9_fid *fid = NULL;
995 struct p9_wstat wstat;
996
997 p9_debug(P9_DEBUG_VFS, "\n");
998 retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
999 if (retval)
1000 return retval;
1001
1002 v9ses = v9fs_dentry2v9ses(dentry);
1003 if (iattr->ia_valid & ATTR_FILE) {
1004 fid = iattr->ia_file->private_data;
1005 WARN_ON(!fid);
1006 }
1007 if (!fid) {
1008 fid = v9fs_fid_lookup(dentry);
1009 use_dentry = 1;
1010 }
1011 if (IS_ERR(fid))
1012 return PTR_ERR(fid);
1013
1014 v9fs_blank_wstat(&wstat);
1015 if (iattr->ia_valid & ATTR_MODE)
1016 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1017
1018 if (iattr->ia_valid & ATTR_MTIME)
1019 wstat.mtime = iattr->ia_mtime.tv_sec;
1020
1021 if (iattr->ia_valid & ATTR_ATIME)
1022 wstat.atime = iattr->ia_atime.tv_sec;
1023
1024 if (iattr->ia_valid & ATTR_SIZE)
1025 wstat.length = iattr->ia_size;
1026
1027 if (v9fs_proto_dotu(v9ses)) {
1028 if (iattr->ia_valid & ATTR_UID)
1029 wstat.n_uid = iattr->ia_uid;
1030
1031 if (iattr->ia_valid & ATTR_GID)
1032 wstat.n_gid = iattr->ia_gid;
1033 }
1034
1035 /* Write all dirty data */
1036 if (d_is_reg(dentry)) {
1037 retval = filemap_fdatawrite(inode->i_mapping);
1038 if (retval)
1039 p9_debug(P9_DEBUG_ERROR,
1040 "flushing writeback during setattr returned %d\n", retval);
1041 }
1042
1043 retval = p9_client_wstat(fid, &wstat);
1044
1045 if (use_dentry)
1046 p9_fid_put(fid);
1047
1048 if (retval < 0)
1049 return retval;
1050
1051 if ((iattr->ia_valid & ATTR_SIZE) &&
1052 iattr->ia_size != i_size_read(inode)) {
1053 truncate_setsize(inode, iattr->ia_size);
1054 netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1055
1056 #ifdef CONFIG_9P_FSCACHE
1057 if (v9ses->cache & CACHE_FSCACHE) {
1058 struct v9fs_inode *v9inode = V9FS_I(inode);
1059
1060 fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1061 }
1062 #endif
1063 }
1064
1065 v9fs_invalidate_inode_attr(inode);
1066
1067 setattr_copy(&nop_mnt_idmap, inode, iattr);
1068 mark_inode_dirty(inode);
1069 return 0;
1070 }
1071
1072 /**
1073 * v9fs_stat2inode - populate an inode structure with mistat info
1074 * @stat: Plan 9 metadata (mistat) structure
1075 * @inode: inode to populate
1076 * @sb: superblock of filesystem
1077 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1078 *
1079 */
1080
1081 void
1082 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1083 struct super_block *sb, unsigned int flags)
1084 {
1085 umode_t mode;
1086 struct v9fs_session_info *v9ses = sb->s_fs_info;
1087 struct v9fs_inode *v9inode = V9FS_I(inode);
1088
1089 inode_set_atime(inode, stat->atime, 0);
1090 inode_set_mtime(inode, stat->mtime, 0);
1091 inode_set_ctime(inode, stat->mtime, 0);
1092
1093 inode->i_uid = v9ses->dfltuid;
1094 inode->i_gid = v9ses->dfltgid;
1095
1096 if (v9fs_proto_dotu(v9ses)) {
1097 inode->i_uid = stat->n_uid;
1098 inode->i_gid = stat->n_gid;
1099 }
1100 if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1101 if (v9fs_proto_dotu(v9ses)) {
1102 unsigned int i_nlink;
1103 /*
1104 * Hadlink support got added later to the .u extension.
1105 * So there can be a server out there that doesn't
1106 * support this even with .u extension. That would
1107 * just leave us with stat->extension being an empty
1108 * string, though.
1109 */
1110 /* HARDLINKCOUNT %u */
1111 if (sscanf(stat->extension,
1112 " HARDLINKCOUNT %u", &i_nlink) == 1)
1113 set_nlink(inode, i_nlink);
1114 }
1115 }
1116 mode = p9mode2perm(v9ses, stat);
1117 mode |= inode->i_mode & ~S_IALLUGO;
1118 inode->i_mode = mode;
1119
1120 v9inode->netfs.remote_i_size = stat->length;
1121 if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1122 v9fs_i_size_write(inode, stat->length);
1123 /* not real number of blocks, but 512 byte ones ... */
1124 inode->i_blocks = (stat->length + 512 - 1) >> 9;
1125 v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1126 }
1127
1128 /**
1129 * v9fs_vfs_get_link - follow a symlink path
1130 * @dentry: dentry for symlink
1131 * @inode: inode for symlink
1132 * @done: delayed call for when we are done with the return value
1133 */
1134
1135 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1136 struct inode *inode,
1137 struct delayed_call *done)
1138 {
1139 struct v9fs_session_info *v9ses;
1140 struct p9_fid *fid;
1141 struct p9_wstat *st;
1142 char *res;
1143
1144 if (!dentry)
1145 return ERR_PTR(-ECHILD);
1146
1147 v9ses = v9fs_dentry2v9ses(dentry);
1148 if (!v9fs_proto_dotu(v9ses))
1149 return ERR_PTR(-EBADF);
1150
1151 p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1152 fid = v9fs_fid_lookup(dentry);
1153
1154 if (IS_ERR(fid))
1155 return ERR_CAST(fid);
1156
1157 st = p9_client_stat(fid);
1158 p9_fid_put(fid);
1159 if (IS_ERR(st))
1160 return ERR_CAST(st);
1161
1162 if (!(st->mode & P9_DMSYMLINK)) {
1163 p9stat_free(st);
1164 kfree(st);
1165 return ERR_PTR(-EINVAL);
1166 }
1167 res = st->extension;
1168 st->extension = NULL;
1169 if (strlen(res) >= PATH_MAX)
1170 res[PATH_MAX - 1] = '\0';
1171
1172 p9stat_free(st);
1173 kfree(st);
1174 set_delayed_call(done, kfree_link, res);
1175 return res;
1176 }
1177
1178 /**
1179 * v9fs_vfs_mkspecial - create a special file
1180 * @dir: inode to create special file in
1181 * @dentry: dentry to create
1182 * @perm: mode to create special file
1183 * @extension: 9p2000.u format extension string representing special file
1184 *
1185 */
1186
1187 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1188 u32 perm, const char *extension)
1189 {
1190 struct p9_fid *fid;
1191 struct v9fs_session_info *v9ses;
1192
1193 v9ses = v9fs_inode2v9ses(dir);
1194 if (!v9fs_proto_dotu(v9ses)) {
1195 p9_debug(P9_DEBUG_ERROR, "not extended\n");
1196 return -EPERM;
1197 }
1198
1199 fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1200 P9_OREAD);
1201 if (IS_ERR(fid))
1202 return PTR_ERR(fid);
1203
1204 v9fs_invalidate_inode_attr(dir);
1205 p9_fid_put(fid);
1206 return 0;
1207 }
1208
1209 /**
1210 * v9fs_vfs_symlink - helper function to create symlinks
1211 * @idmap: idmap of the mount
1212 * @dir: directory inode containing symlink
1213 * @dentry: dentry for symlink
1214 * @symname: symlink data
1215 *
1216 * See Also: 9P2000.u RFC for more information
1217 *
1218 */
1219
1220 static int
1221 v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1222 struct dentry *dentry, const char *symname)
1223 {
1224 p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1225 dir->i_ino, dentry, symname);
1226
1227 return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1228 }
1229
1230 #define U32_MAX_DIGITS 10
1231
1232 /**
1233 * v9fs_vfs_link - create a hardlink
1234 * @old_dentry: dentry for file to link to
1235 * @dir: inode destination for new link
1236 * @dentry: dentry for link
1237 *
1238 */
1239
1240 static int
1241 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1242 struct dentry *dentry)
1243 {
1244 int retval;
1245 char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1246 struct p9_fid *oldfid;
1247
1248 p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1249 dir->i_ino, dentry, old_dentry);
1250
1251 oldfid = v9fs_fid_clone(old_dentry);
1252 if (IS_ERR(oldfid))
1253 return PTR_ERR(oldfid);
1254
1255 sprintf(name, "%d\n", oldfid->fid);
1256 retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1257 if (!retval) {
1258 v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1259 v9fs_invalidate_inode_attr(dir);
1260 }
1261 p9_fid_put(oldfid);
1262 return retval;
1263 }
1264
1265 /**
1266 * v9fs_vfs_mknod - create a special file
1267 * @idmap: idmap of the mount
1268 * @dir: inode destination for new link
1269 * @dentry: dentry for file
1270 * @mode: mode for creation
1271 * @rdev: device associated with special file
1272 *
1273 */
1274
1275 static int
1276 v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1277 struct dentry *dentry, umode_t mode, dev_t rdev)
1278 {
1279 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1280 int retval;
1281 char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1282 u32 perm;
1283
1284 p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1285 dir->i_ino, dentry, mode,
1286 MAJOR(rdev), MINOR(rdev));
1287
1288 /* build extension */
1289 if (S_ISBLK(mode))
1290 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1291 else if (S_ISCHR(mode))
1292 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1293 else
1294 *name = 0;
1295
1296 perm = unixmode2p9mode(v9ses, mode);
1297 retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1298
1299 return retval;
1300 }
1301
1302 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1303 {
1304 int umode;
1305 dev_t rdev;
1306 struct p9_wstat *st;
1307 struct v9fs_session_info *v9ses;
1308 unsigned int flags;
1309
1310 v9ses = v9fs_inode2v9ses(inode);
1311 st = p9_client_stat(fid);
1312 if (IS_ERR(st))
1313 return PTR_ERR(st);
1314 /*
1315 * Don't update inode if the file type is different
1316 */
1317 umode = p9mode2unixmode(v9ses, st, &rdev);
1318 if (inode_wrong_type(inode, umode))
1319 goto out;
1320
1321 /*
1322 * We don't want to refresh inode->i_size,
1323 * because we may have cached data
1324 */
1325 flags = (v9ses->cache & CACHE_LOOSE) ?
1326 V9FS_STAT2INODE_KEEP_ISIZE : 0;
1327 v9fs_stat2inode(st, inode, inode->i_sb, flags);
1328 out:
1329 p9stat_free(st);
1330 kfree(st);
1331 return 0;
1332 }
1333
1334 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1335 .create = v9fs_vfs_create,
1336 .lookup = v9fs_vfs_lookup,
1337 .atomic_open = v9fs_vfs_atomic_open,
1338 .symlink = v9fs_vfs_symlink,
1339 .link = v9fs_vfs_link,
1340 .unlink = v9fs_vfs_unlink,
1341 .mkdir = v9fs_vfs_mkdir,
1342 .rmdir = v9fs_vfs_rmdir,
1343 .mknod = v9fs_vfs_mknod,
1344 .rename = v9fs_vfs_rename,
1345 .getattr = v9fs_vfs_getattr,
1346 .setattr = v9fs_vfs_setattr,
1347 };
1348
1349 static const struct inode_operations v9fs_dir_inode_operations = {
1350 .create = v9fs_vfs_create,
1351 .lookup = v9fs_vfs_lookup,
1352 .atomic_open = v9fs_vfs_atomic_open,
1353 .unlink = v9fs_vfs_unlink,
1354 .mkdir = v9fs_vfs_mkdir,
1355 .rmdir = v9fs_vfs_rmdir,
1356 .mknod = v9fs_vfs_mknod,
1357 .rename = v9fs_vfs_rename,
1358 .getattr = v9fs_vfs_getattr,
1359 .setattr = v9fs_vfs_setattr,
1360 };
1361
1362 static const struct inode_operations v9fs_file_inode_operations = {
1363 .getattr = v9fs_vfs_getattr,
1364 .setattr = v9fs_vfs_setattr,
1365 };
1366
1367 static const struct inode_operations v9fs_symlink_inode_operations = {
1368 .get_link = v9fs_vfs_get_link,
1369 .getattr = v9fs_vfs_getattr,
1370 .setattr = v9fs_vfs_setattr,
1371 };
1372
1373
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