Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/dir.c
4 *
5 * Copyright (C) 1992 Rick Sladkey
6 *
7 * nfs directory handling functions
8 *
9 * 10 Apr 1996 Added silly rename for unlink --okir
10 * 28 Sep 1996 Improved directory cache --okir
11 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de
12 * Re-implemented silly rename for unlink, newly implemented
13 * silly rename for nfs_rename() following the suggestions
14 * of Olaf Kirch (okir) found in this file.
15 * Following Linus comments on my original hack, this version
16 * depends only on the dcache stuff and doesn't touch the inode
17 * layer (iput() and friends).
18 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM
19 */
20
21#include <linux/module.h>
22#include <linux/time.h>
23#include <linux/errno.h>
24#include <linux/stat.h>
25#include <linux/fcntl.h>
26#include <linux/string.h>
27#include <linux/kernel.h>
28#include <linux/slab.h>
29#include <linux/mm.h>
30#include <linux/sunrpc/clnt.h>
31#include <linux/nfs_fs.h>
32#include <linux/nfs_mount.h>
33#include <linux/pagemap.h>
34#include <linux/pagevec.h>
35#include <linux/namei.h>
36#include <linux/mount.h>
37#include <linux/swap.h>
38#include <linux/sched.h>
39#include <linux/kmemleak.h>
40#include <linux/xattr.h>
41
42#include "delegation.h"
43#include "iostat.h"
44#include "internal.h"
45#include "fscache.h"
46
47#include "nfstrace.h"
48
49/* #define NFS_DEBUG_VERBOSE 1 */
50
51static int nfs_opendir(struct inode *, struct file *);
52static int nfs_closedir(struct inode *, struct file *);
53static int nfs_readdir(struct file *, struct dir_context *);
54static int nfs_fsync_dir(struct file *, loff_t, loff_t, int);
55static loff_t nfs_llseek_dir(struct file *, loff_t, int);
56static void nfs_readdir_clear_array(struct page*);
57
58const struct file_operations nfs_dir_operations = {
59 .llseek = nfs_llseek_dir,
60 .read = generic_read_dir,
61 .iterate_shared = nfs_readdir,
62 .open = nfs_opendir,
63 .release = nfs_closedir,
64 .fsync = nfs_fsync_dir,
65};
66
67const struct address_space_operations nfs_dir_aops = {
68 .freepage = nfs_readdir_clear_array,
69};
70
71static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir)
72{
73 struct nfs_inode *nfsi = NFS_I(dir);
74 struct nfs_open_dir_context *ctx;
75 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
76 if (ctx != NULL) {
77 ctx->duped = 0;
78 ctx->attr_gencount = nfsi->attr_gencount;
79 ctx->dir_cookie = 0;
80 ctx->dup_cookie = 0;
81 spin_lock(&dir->i_lock);
82 if (list_empty(&nfsi->open_files) &&
83 (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
84 nfs_set_cache_invalid(dir,
85 NFS_INO_INVALID_DATA |
86 NFS_INO_REVAL_FORCED);
87 list_add(&ctx->list, &nfsi->open_files);
88 spin_unlock(&dir->i_lock);
89 return ctx;
90 }
91 return ERR_PTR(-ENOMEM);
92}
93
94static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
95{
96 spin_lock(&dir->i_lock);
97 list_del(&ctx->list);
98 spin_unlock(&dir->i_lock);
99 kfree(ctx);
100}
101
102/*
103 * Open file
104 */
105static int
106nfs_opendir(struct inode *inode, struct file *filp)
107{
108 int res = 0;
109 struct nfs_open_dir_context *ctx;
110
111 dfprintk(FILE, "NFS: open dir(%pD2)\n", filp);
112
113 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
114
115 ctx = alloc_nfs_open_dir_context(inode);
116 if (IS_ERR(ctx)) {
117 res = PTR_ERR(ctx);
118 goto out;
119 }
120 filp->private_data = ctx;
121out:
122 return res;
123}
124
125static int
126nfs_closedir(struct inode *inode, struct file *filp)
127{
128 put_nfs_open_dir_context(file_inode(filp), filp->private_data);
129 return 0;
130}
131
132struct nfs_cache_array_entry {
133 u64 cookie;
134 u64 ino;
135 const char *name;
136 unsigned int name_len;
137 unsigned char d_type;
138};
139
140struct nfs_cache_array {
141 u64 last_cookie;
142 unsigned int size;
143 unsigned char page_full : 1,
144 page_is_eof : 1,
145 cookies_are_ordered : 1;
146 struct nfs_cache_array_entry array[];
147};
148
149struct nfs_readdir_descriptor {
150 struct file *file;
151 struct page *page;
152 struct dir_context *ctx;
153 pgoff_t page_index;
154 u64 dir_cookie;
155 u64 last_cookie;
156 u64 dup_cookie;
157 loff_t current_index;
158 loff_t prev_index;
159
160 __be32 verf[NFS_DIR_VERIFIER_SIZE];
161 unsigned long dir_verifier;
162 unsigned long timestamp;
163 unsigned long gencount;
164 unsigned long attr_gencount;
165 unsigned int cache_entry_index;
166 signed char duped;
167 bool plus;
168 bool eof;
169};
170
171static void nfs_readdir_array_init(struct nfs_cache_array *array)
172{
173 memset(array, 0, sizeof(struct nfs_cache_array));
174}
175
176static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie)
177{
178 struct nfs_cache_array *array;
179
180 array = kmap_atomic(page);
181 nfs_readdir_array_init(array);
182 array->last_cookie = last_cookie;
183 array->cookies_are_ordered = 1;
184 kunmap_atomic(array);
185}
186
187/*
188 * we are freeing strings created by nfs_add_to_readdir_array()
189 */
190static
191void nfs_readdir_clear_array(struct page *page)
192{
193 struct nfs_cache_array *array;
194 int i;
195
196 array = kmap_atomic(page);
197 for (i = 0; i < array->size; i++)
198 kfree(array->array[i].name);
199 nfs_readdir_array_init(array);
200 kunmap_atomic(array);
201}
202
203static struct page *
204nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags)
205{
206 struct page *page = alloc_page(gfp_flags);
207 if (page)
208 nfs_readdir_page_init_array(page, last_cookie);
209 return page;
210}
211
212static void nfs_readdir_page_array_free(struct page *page)
213{
214 if (page) {
215 nfs_readdir_clear_array(page);
216 put_page(page);
217 }
218}
219
220static void nfs_readdir_array_set_eof(struct nfs_cache_array *array)
221{
222 array->page_is_eof = 1;
223 array->page_full = 1;
224}
225
226static bool nfs_readdir_array_is_full(struct nfs_cache_array *array)
227{
228 return array->page_full;
229}
230
231/*
232 * the caller is responsible for freeing qstr.name
233 * when called by nfs_readdir_add_to_array, the strings will be freed in
234 * nfs_clear_readdir_array()
235 */
236static const char *nfs_readdir_copy_name(const char *name, unsigned int len)
237{
238 const char *ret = kmemdup_nul(name, len, GFP_KERNEL);
239
240 /*
241 * Avoid a kmemleak false positive. The pointer to the name is stored
242 * in a page cache page which kmemleak does not scan.
243 */
244 if (ret != NULL)
245 kmemleak_not_leak(ret);
246 return ret;
247}
248
249/*
250 * Check that the next array entry lies entirely within the page bounds
251 */
252static int nfs_readdir_array_can_expand(struct nfs_cache_array *array)
253{
254 struct nfs_cache_array_entry *cache_entry;
255
256 if (array->page_full)
257 return -ENOSPC;
258 cache_entry = &array->array[array->size + 1];
259 if ((char *)cache_entry - (char *)array > PAGE_SIZE) {
260 array->page_full = 1;
261 return -ENOSPC;
262 }
263 return 0;
264}
265
266static
267int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
268{
269 struct nfs_cache_array *array;
270 struct nfs_cache_array_entry *cache_entry;
271 const char *name;
272 int ret;
273
274 name = nfs_readdir_copy_name(entry->name, entry->len);
275 if (!name)
276 return -ENOMEM;
277
278 array = kmap_atomic(page);
279 ret = nfs_readdir_array_can_expand(array);
280 if (ret) {
281 kfree(name);
282 goto out;
283 }
284
285 cache_entry = &array->array[array->size];
286 cache_entry->cookie = entry->prev_cookie;
287 cache_entry->ino = entry->ino;
288 cache_entry->d_type = entry->d_type;
289 cache_entry->name_len = entry->len;
290 cache_entry->name = name;
291 array->last_cookie = entry->cookie;
292 if (array->last_cookie <= cache_entry->cookie)
293 array->cookies_are_ordered = 0;
294 array->size++;
295 if (entry->eof != 0)
296 nfs_readdir_array_set_eof(array);
297out:
298 kunmap_atomic(array);
299 return ret;
300}
301
302static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
303 pgoff_t index, u64 last_cookie)
304{
305 struct page *page;
306
307 page = grab_cache_page(mapping, index);
308 if (page && !PageUptodate(page)) {
309 nfs_readdir_page_init_array(page, last_cookie);
310 if (invalidate_inode_pages2_range(mapping, index + 1, -1) < 0)
311 nfs_zap_mapping(mapping->host, mapping);
312 SetPageUptodate(page);
313 }
314
315 return page;
316}
317
318static u64 nfs_readdir_page_last_cookie(struct page *page)
319{
320 struct nfs_cache_array *array;
321 u64 ret;
322
323 array = kmap_atomic(page);
324 ret = array->last_cookie;
325 kunmap_atomic(array);
326 return ret;
327}
328
329static bool nfs_readdir_page_needs_filling(struct page *page)
330{
331 struct nfs_cache_array *array;
332 bool ret;
333
334 array = kmap_atomic(page);
335 ret = !nfs_readdir_array_is_full(array);
336 kunmap_atomic(array);
337 return ret;
338}
339
340static void nfs_readdir_page_set_eof(struct page *page)
341{
342 struct nfs_cache_array *array;
343
344 array = kmap_atomic(page);
345 nfs_readdir_array_set_eof(array);
346 kunmap_atomic(array);
347}
348
349static void nfs_readdir_page_unlock_and_put(struct page *page)
350{
351 unlock_page(page);
352 put_page(page);
353}
354
355static struct page *nfs_readdir_page_get_next(struct address_space *mapping,
356 pgoff_t index, u64 cookie)
357{
358 struct page *page;
359
360 page = nfs_readdir_page_get_locked(mapping, index, cookie);
361 if (page) {
362 if (nfs_readdir_page_last_cookie(page) == cookie)
363 return page;
364 nfs_readdir_page_unlock_and_put(page);
365 }
366 return NULL;
367}
368
369static inline
370int is_32bit_api(void)
371{
372#ifdef CONFIG_COMPAT
373 return in_compat_syscall();
374#else
375 return (BITS_PER_LONG == 32);
376#endif
377}
378
379static
380bool nfs_readdir_use_cookie(const struct file *filp)
381{
382 if ((filp->f_mode & FMODE_32BITHASH) ||
383 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
384 return false;
385 return true;
386}
387
388static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,
389 struct nfs_readdir_descriptor *desc)
390{
391 loff_t diff = desc->ctx->pos - desc->current_index;
392 unsigned int index;
393
394 if (diff < 0)
395 goto out_eof;
396 if (diff >= array->size) {
397 if (array->page_is_eof)
398 goto out_eof;
399 return -EAGAIN;
400 }
401
402 index = (unsigned int)diff;
403 desc->dir_cookie = array->array[index].cookie;
404 desc->cache_entry_index = index;
405 return 0;
406out_eof:
407 desc->eof = true;
408 return -EBADCOOKIE;
409}
410
411static bool
412nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
413{
414 if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))
415 return false;
416 smp_rmb();
417 return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
418}
419
420static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array,
421 u64 cookie)
422{
423 if (!array->cookies_are_ordered)
424 return true;
425 /* Optimisation for monotonically increasing cookies */
426 if (cookie >= array->last_cookie)
427 return false;
428 if (array->size && cookie < array->array[0].cookie)
429 return false;
430 return true;
431}
432
433static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
434 struct nfs_readdir_descriptor *desc)
435{
436 int i;
437 loff_t new_pos;
438 int status = -EAGAIN;
439
440 if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie))
441 goto check_eof;
442
443 for (i = 0; i < array->size; i++) {
444 if (array->array[i].cookie == desc->dir_cookie) {
445 struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));
446
447 new_pos = desc->current_index + i;
448 if (desc->attr_gencount != nfsi->attr_gencount ||
449 !nfs_readdir_inode_mapping_valid(nfsi)) {
450 desc->duped = 0;
451 desc->attr_gencount = nfsi->attr_gencount;
452 } else if (new_pos < desc->prev_index) {
453 if (desc->duped > 0
454 && desc->dup_cookie == desc->dir_cookie) {
455 if (printk_ratelimit()) {
456 pr_notice("NFS: directory %pD2 contains a readdir loop."
457 "Please contact your server vendor. "
458 "The file: %s has duplicate cookie %llu\n",
459 desc->file, array->array[i].name, desc->dir_cookie);
460 }
461 status = -ELOOP;
462 goto out;
463 }
464 desc->dup_cookie = desc->dir_cookie;
465 desc->duped = -1;
466 }
467 if (nfs_readdir_use_cookie(desc->file))
468 desc->ctx->pos = desc->dir_cookie;
469 else
470 desc->ctx->pos = new_pos;
471 desc->prev_index = new_pos;
472 desc->cache_entry_index = i;
473 return 0;
474 }
475 }
476check_eof:
477 if (array->page_is_eof) {
478 status = -EBADCOOKIE;
479 if (desc->dir_cookie == array->last_cookie)
480 desc->eof = true;
481 }
482out:
483 return status;
484}
485
486static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc)
487{
488 struct nfs_cache_array *array;
489 int status;
490
491 array = kmap_atomic(desc->page);
492
493 if (desc->dir_cookie == 0)
494 status = nfs_readdir_search_for_pos(array, desc);
495 else
496 status = nfs_readdir_search_for_cookie(array, desc);
497
498 if (status == -EAGAIN) {
499 desc->last_cookie = array->last_cookie;
500 desc->current_index += array->size;
501 desc->page_index++;
502 }
503 kunmap_atomic(array);
504 return status;
505}
506
507/* Fill a page with xdr information before transferring to the cache page */
508static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
509 __be32 *verf, u64 cookie,
510 struct page **pages, size_t bufsize,
511 __be32 *verf_res)
512{
513 struct inode *inode = file_inode(desc->file);
514 struct nfs_readdir_arg arg = {
515 .dentry = file_dentry(desc->file),
516 .cred = desc->file->f_cred,
517 .verf = verf,
518 .cookie = cookie,
519 .pages = pages,
520 .page_len = bufsize,
521 .plus = desc->plus,
522 };
523 struct nfs_readdir_res res = {
524 .verf = verf_res,
525 };
526 unsigned long timestamp, gencount;
527 int error;
528
529 again:
530 timestamp = jiffies;
531 gencount = nfs_inc_attr_generation_counter();
532 desc->dir_verifier = nfs_save_change_attribute(inode);
533 error = NFS_PROTO(inode)->readdir(&arg, &res);
534 if (error < 0) {
535 /* We requested READDIRPLUS, but the server doesn't grok it */
536 if (error == -ENOTSUPP && desc->plus) {
537 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
538 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
539 desc->plus = arg.plus = false;
540 goto again;
541 }
542 goto error;
543 }
544 desc->timestamp = timestamp;
545 desc->gencount = gencount;
546error:
547 return error;
548}
549
550static int xdr_decode(struct nfs_readdir_descriptor *desc,
551 struct nfs_entry *entry, struct xdr_stream *xdr)
552{
553 struct inode *inode = file_inode(desc->file);
554 int error;
555
556 error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus);
557 if (error)
558 return error;
559 entry->fattr->time_start = desc->timestamp;
560 entry->fattr->gencount = desc->gencount;
561 return 0;
562}
563
564/* Match file and dirent using either filehandle or fileid
565 * Note: caller is responsible for checking the fsid
566 */
567static
568int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
569{
570 struct inode *inode;
571 struct nfs_inode *nfsi;
572
573 if (d_really_is_negative(dentry))
574 return 0;
575
576 inode = d_inode(dentry);
577 if (is_bad_inode(inode) || NFS_STALE(inode))
578 return 0;
579
580 nfsi = NFS_I(inode);
581 if (entry->fattr->fileid != nfsi->fileid)
582 return 0;
583 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0)
584 return 0;
585 return 1;
586}
587
588static
589bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx)
590{
591 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
592 return false;
593 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags))
594 return true;
595 if (ctx->pos == 0)
596 return true;
597 return false;
598}
599
600/*
601 * This function is called by the lookup and getattr code to request the
602 * use of readdirplus to accelerate any future lookups in the same
603 * directory.
604 */
605void nfs_advise_use_readdirplus(struct inode *dir)
606{
607 struct nfs_inode *nfsi = NFS_I(dir);
608
609 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
610 !list_empty(&nfsi->open_files))
611 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
612}
613
614/*
615 * This function is mainly for use by nfs_getattr().
616 *
617 * If this is an 'ls -l', we want to force use of readdirplus.
618 * Do this by checking if there is an active file descriptor
619 * and calling nfs_advise_use_readdirplus, then forcing a
620 * cache flush.
621 */
622void nfs_force_use_readdirplus(struct inode *dir)
623{
624 struct nfs_inode *nfsi = NFS_I(dir);
625
626 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
627 !list_empty(&nfsi->open_files)) {
628 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
629 invalidate_mapping_pages(dir->i_mapping,
630 nfsi->page_index + 1, -1);
631 }
632}
633
634static
635void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
636 unsigned long dir_verifier)
637{
638 struct qstr filename = QSTR_INIT(entry->name, entry->len);
639 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
640 struct dentry *dentry;
641 struct dentry *alias;
642 struct inode *inode;
643 int status;
644
645 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID))
646 return;
647 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID))
648 return;
649 if (filename.len == 0)
650 return;
651 /* Validate that the name doesn't contain any illegal '\0' */
652 if (strnlen(filename.name, filename.len) != filename.len)
653 return;
654 /* ...or '/' */
655 if (strnchr(filename.name, filename.len, '/'))
656 return;
657 if (filename.name[0] == '.') {
658 if (filename.len == 1)
659 return;
660 if (filename.len == 2 && filename.name[1] == '.')
661 return;
662 }
663 filename.hash = full_name_hash(parent, filename.name, filename.len);
664
665 dentry = d_lookup(parent, &filename);
666again:
667 if (!dentry) {
668 dentry = d_alloc_parallel(parent, &filename, &wq);
669 if (IS_ERR(dentry))
670 return;
671 }
672 if (!d_in_lookup(dentry)) {
673 /* Is there a mountpoint here? If so, just exit */
674 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid,
675 &entry->fattr->fsid))
676 goto out;
677 if (nfs_same_file(dentry, entry)) {
678 if (!entry->fh->size)
679 goto out;
680 nfs_set_verifier(dentry, dir_verifier);
681 status = nfs_refresh_inode(d_inode(dentry), entry->fattr);
682 if (!status)
683 nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label);
684 goto out;
685 } else {
686 d_invalidate(dentry);
687 dput(dentry);
688 dentry = NULL;
689 goto again;
690 }
691 }
692 if (!entry->fh->size) {
693 d_lookup_done(dentry);
694 goto out;
695 }
696
697 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label);
698 alias = d_splice_alias(inode, dentry);
699 d_lookup_done(dentry);
700 if (alias) {
701 if (IS_ERR(alias))
702 goto out;
703 dput(dentry);
704 dentry = alias;
705 }
706 nfs_set_verifier(dentry, dir_verifier);
707out:
708 dput(dentry);
709}
710
711/* Perform conversion from xdr to cache array */
712static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
713 struct nfs_entry *entry,
714 struct page **xdr_pages,
715 unsigned int buflen,
716 struct page **arrays,
717 size_t narrays)
718{
719 struct address_space *mapping = desc->file->f_mapping;
720 struct xdr_stream stream;
721 struct xdr_buf buf;
722 struct page *scratch, *new, *page = *arrays;
723 int status;
724
725 scratch = alloc_page(GFP_KERNEL);
726 if (scratch == NULL)
727 return -ENOMEM;
728
729 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
730 xdr_set_scratch_page(&stream, scratch);
731
732 do {
733 if (entry->label)
734 entry->label->len = NFS4_MAXLABELLEN;
735
736 status = xdr_decode(desc, entry, &stream);
737 if (status != 0)
738 break;
739
740 if (desc->plus)
741 nfs_prime_dcache(file_dentry(desc->file), entry,
742 desc->dir_verifier);
743
744 status = nfs_readdir_add_to_array(entry, page);
745 if (status != -ENOSPC)
746 continue;
747
748 if (page->mapping != mapping) {
749 if (!--narrays)
750 break;
751 new = nfs_readdir_page_array_alloc(entry->prev_cookie,
752 GFP_KERNEL);
753 if (!new)
754 break;
755 arrays++;
756 *arrays = page = new;
757 } else {
758 new = nfs_readdir_page_get_next(mapping,
759 page->index + 1,
760 entry->prev_cookie);
761 if (!new)
762 break;
763 if (page != *arrays)
764 nfs_readdir_page_unlock_and_put(page);
765 page = new;
766 }
767 status = nfs_readdir_add_to_array(entry, page);
768 } while (!status && !entry->eof);
769
770 switch (status) {
771 case -EBADCOOKIE:
772 if (entry->eof) {
773 nfs_readdir_page_set_eof(page);
774 status = 0;
775 }
776 break;
777 case -ENOSPC:
778 case -EAGAIN:
779 status = 0;
780 break;
781 }
782
783 if (page != *arrays)
784 nfs_readdir_page_unlock_and_put(page);
785
786 put_page(scratch);
787 return status;
788}
789
790static void nfs_readdir_free_pages(struct page **pages, size_t npages)
791{
792 while (npages--)
793 put_page(pages[npages]);
794 kfree(pages);
795}
796
797/*
798 * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call
799 * to nfs_readdir_free_pages()
800 */
801static struct page **nfs_readdir_alloc_pages(size_t npages)
802{
803 struct page **pages;
804 size_t i;
805
806 pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
807 if (!pages)
808 return NULL;
809 for (i = 0; i < npages; i++) {
810 struct page *page = alloc_page(GFP_KERNEL);
811 if (page == NULL)
812 goto out_freepages;
813 pages[i] = page;
814 }
815 return pages;
816
817out_freepages:
818 nfs_readdir_free_pages(pages, i);
819 return NULL;
820}
821
822static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
823 __be32 *verf_arg, __be32 *verf_res,
824 struct page **arrays, size_t narrays)
825{
826 struct page **pages;
827 struct page *page = *arrays;
828 struct nfs_entry *entry;
829 size_t array_size;
830 struct inode *inode = file_inode(desc->file);
831 size_t dtsize = NFS_SERVER(inode)->dtsize;
832 int status = -ENOMEM;
833
834 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
835 if (!entry)
836 return -ENOMEM;
837 entry->cookie = nfs_readdir_page_last_cookie(page);
838 entry->fh = nfs_alloc_fhandle();
839 entry->fattr = nfs_alloc_fattr();
840 entry->server = NFS_SERVER(inode);
841 if (entry->fh == NULL || entry->fattr == NULL)
842 goto out;
843
844 entry->label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);
845 if (IS_ERR(entry->label)) {
846 status = PTR_ERR(entry->label);
847 goto out;
848 }
849
850 array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
851 pages = nfs_readdir_alloc_pages(array_size);
852 if (!pages)
853 goto out_release_label;
854
855 do {
856 unsigned int pglen;
857 status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie,
858 pages, dtsize,
859 verf_res);
860 if (status < 0)
861 break;
862
863 pglen = status;
864 if (pglen == 0) {
865 nfs_readdir_page_set_eof(page);
866 break;
867 }
868
869 verf_arg = verf_res;
870
871 status = nfs_readdir_page_filler(desc, entry, pages, pglen,
872 arrays, narrays);
873 } while (!status && nfs_readdir_page_needs_filling(page));
874
875 nfs_readdir_free_pages(pages, array_size);
876out_release_label:
877 nfs4_label_free(entry->label);
878out:
879 nfs_free_fattr(entry->fattr);
880 nfs_free_fhandle(entry->fh);
881 kfree(entry);
882 return status;
883}
884
885static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc)
886{
887 put_page(desc->page);
888 desc->page = NULL;
889}
890
891static void
892nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc)
893{
894 unlock_page(desc->page);
895 nfs_readdir_page_put(desc);
896}
897
898static struct page *
899nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
900{
901 return nfs_readdir_page_get_locked(desc->file->f_mapping,
902 desc->page_index,
903 desc->last_cookie);
904}
905
906/*
907 * Returns 0 if desc->dir_cookie was found on page desc->page_index
908 * and locks the page to prevent removal from the page cache.
909 */
910static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
911{
912 struct inode *inode = file_inode(desc->file);
913 struct nfs_inode *nfsi = NFS_I(inode);
914 __be32 verf[NFS_DIR_VERIFIER_SIZE];
915 int res;
916
917 desc->page = nfs_readdir_page_get_cached(desc);
918 if (!desc->page)
919 return -ENOMEM;
920 if (nfs_readdir_page_needs_filling(desc->page)) {
921 res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf,
922 &desc->page, 1);
923 if (res < 0) {
924 nfs_readdir_page_unlock_and_put_cached(desc);
925 if (res == -EBADCOOKIE || res == -ENOTSYNC) {
926 invalidate_inode_pages2(desc->file->f_mapping);
927 desc->page_index = 0;
928 return -EAGAIN;
929 }
930 return res;
931 }
932 /*
933 * Set the cookie verifier if the page cache was empty
934 */
935 if (desc->page_index == 0)
936 memcpy(nfsi->cookieverf, verf,
937 sizeof(nfsi->cookieverf));
938 }
939 res = nfs_readdir_search_array(desc);
940 if (res == 0) {
941 nfsi->page_index = desc->page_index;
942 return 0;
943 }
944 nfs_readdir_page_unlock_and_put_cached(desc);
945 return res;
946}
947
948static bool nfs_readdir_dont_search_cache(struct nfs_readdir_descriptor *desc)
949{
950 struct address_space *mapping = desc->file->f_mapping;
951 struct inode *dir = file_inode(desc->file);
952 unsigned int dtsize = NFS_SERVER(dir)->dtsize;
953 loff_t size = i_size_read(dir);
954
955 /*
956 * Default to uncached readdir if the page cache is empty, and
957 * we're looking for a non-zero cookie in a large directory.
958 */
959 return desc->dir_cookie != 0 && mapping->nrpages == 0 && size > dtsize;
960}
961
962/* Search for desc->dir_cookie from the beginning of the page cache */
963static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
964{
965 int res;
966
967 if (nfs_readdir_dont_search_cache(desc))
968 return -EBADCOOKIE;
969
970 do {
971 if (desc->page_index == 0) {
972 desc->current_index = 0;
973 desc->prev_index = 0;
974 desc->last_cookie = 0;
975 }
976 res = find_and_lock_cache_page(desc);
977 } while (res == -EAGAIN);
978 return res;
979}
980
981/*
982 * Once we've found the start of the dirent within a page: fill 'er up...
983 */
984static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
985 const __be32 *verf)
986{
987 struct file *file = desc->file;
988 struct nfs_cache_array *array;
989 unsigned int i = 0;
990
991 array = kmap(desc->page);
992 for (i = desc->cache_entry_index; i < array->size; i++) {
993 struct nfs_cache_array_entry *ent;
994
995 ent = &array->array[i];
996 if (!dir_emit(desc->ctx, ent->name, ent->name_len,
997 nfs_compat_user_ino64(ent->ino), ent->d_type)) {
998 desc->eof = true;
999 break;
1000 }
1001 memcpy(desc->verf, verf, sizeof(desc->verf));
1002 if (i < (array->size-1))
1003 desc->dir_cookie = array->array[i+1].cookie;
1004 else
1005 desc->dir_cookie = array->last_cookie;
1006 if (nfs_readdir_use_cookie(file))
1007 desc->ctx->pos = desc->dir_cookie;
1008 else
1009 desc->ctx->pos++;
1010 if (desc->duped != 0)
1011 desc->duped = 1;
1012 }
1013 if (array->page_is_eof)
1014 desc->eof = true;
1015
1016 kunmap(desc->page);
1017 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n",
1018 (unsigned long long)desc->dir_cookie);
1019}
1020
1021/*
1022 * If we cannot find a cookie in our cache, we suspect that this is
1023 * because it points to a deleted file, so we ask the server to return
1024 * whatever it thinks is the next entry. We then feed this to filldir.
1025 * If all goes well, we should then be able to find our way round the
1026 * cache on the next call to readdir_search_pagecache();
1027 *
1028 * NOTE: we cannot add the anonymous page to the pagecache because
1029 * the data it contains might not be page aligned. Besides,
1030 * we should already have a complete representation of the
1031 * directory in the page cache by the time we get here.
1032 */
1033static int uncached_readdir(struct nfs_readdir_descriptor *desc)
1034{
1035 struct page **arrays;
1036 size_t i, sz = 512;
1037 __be32 verf[NFS_DIR_VERIFIER_SIZE];
1038 int status = -ENOMEM;
1039
1040 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %llu\n",
1041 (unsigned long long)desc->dir_cookie);
1042
1043 arrays = kcalloc(sz, sizeof(*arrays), GFP_KERNEL);
1044 if (!arrays)
1045 goto out;
1046 arrays[0] = nfs_readdir_page_array_alloc(desc->dir_cookie, GFP_KERNEL);
1047 if (!arrays[0])
1048 goto out;
1049
1050 desc->page_index = 0;
1051 desc->last_cookie = desc->dir_cookie;
1052 desc->duped = 0;
1053
1054 status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz);
1055
1056 for (i = 0; !desc->eof && i < sz && arrays[i]; i++) {
1057 desc->page = arrays[i];
1058 nfs_do_filldir(desc, verf);
1059 }
1060 desc->page = NULL;
1061
1062
1063 for (i = 0; i < sz && arrays[i]; i++)
1064 nfs_readdir_page_array_free(arrays[i]);
1065out:
1066 kfree(arrays);
1067 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status);
1068 return status;
1069}
1070
1071/* The file offset position represents the dirent entry number. A
1072 last cookie cache takes care of the common case of reading the
1073 whole directory.
1074 */
1075static int nfs_readdir(struct file *file, struct dir_context *ctx)
1076{
1077 struct dentry *dentry = file_dentry(file);
1078 struct inode *inode = d_inode(dentry);
1079 struct nfs_inode *nfsi = NFS_I(inode);
1080 struct nfs_open_dir_context *dir_ctx = file->private_data;
1081 struct nfs_readdir_descriptor *desc;
1082 int res;
1083
1084 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
1085 file, (long long)ctx->pos);
1086 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
1087
1088 /*
1089 * ctx->pos points to the dirent entry number.
1090 * *desc->dir_cookie has the cookie for the next entry. We have
1091 * to either find the entry with the appropriate number or
1092 * revalidate the cookie.
1093 */
1094 if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) {
1095 res = nfs_revalidate_mapping(inode, file->f_mapping);
1096 if (res < 0)
1097 goto out;
1098 }
1099
1100 res = -ENOMEM;
1101 desc = kzalloc(sizeof(*desc), GFP_KERNEL);
1102 if (!desc)
1103 goto out;
1104 desc->file = file;
1105 desc->ctx = ctx;
1106 desc->plus = nfs_use_readdirplus(inode, ctx);
1107
1108 spin_lock(&file->f_lock);
1109 desc->dir_cookie = dir_ctx->dir_cookie;
1110 desc->dup_cookie = dir_ctx->dup_cookie;
1111 desc->duped = dir_ctx->duped;
1112 desc->attr_gencount = dir_ctx->attr_gencount;
1113 memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));
1114 spin_unlock(&file->f_lock);
1115
1116 do {
1117 res = readdir_search_pagecache(desc);
1118
1119 if (res == -EBADCOOKIE) {
1120 res = 0;
1121 /* This means either end of directory */
1122 if (desc->dir_cookie && !desc->eof) {
1123 /* Or that the server has 'lost' a cookie */
1124 res = uncached_readdir(desc);
1125 if (res == 0)
1126 continue;
1127 if (res == -EBADCOOKIE || res == -ENOTSYNC)
1128 res = 0;
1129 }
1130 break;
1131 }
1132 if (res == -ETOOSMALL && desc->plus) {
1133 clear_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
1134 nfs_zap_caches(inode);
1135 desc->page_index = 0;
1136 desc->plus = false;
1137 desc->eof = false;
1138 continue;
1139 }
1140 if (res < 0)
1141 break;
1142
1143 nfs_do_filldir(desc, nfsi->cookieverf);
1144 nfs_readdir_page_unlock_and_put_cached(desc);
1145 } while (!desc->eof);
1146
1147 spin_lock(&file->f_lock);
1148 dir_ctx->dir_cookie = desc->dir_cookie;
1149 dir_ctx->dup_cookie = desc->dup_cookie;
1150 dir_ctx->duped = desc->duped;
1151 dir_ctx->attr_gencount = desc->attr_gencount;
1152 memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf));
1153 spin_unlock(&file->f_lock);
1154
1155 kfree(desc);
1156
1157out:
1158 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res);
1159 return res;
1160}
1161
1162static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
1163{
1164 struct nfs_open_dir_context *dir_ctx = filp->private_data;
1165
1166 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",
1167 filp, offset, whence);
1168
1169 switch (whence) {
1170 default:
1171 return -EINVAL;
1172 case SEEK_SET:
1173 if (offset < 0)
1174 return -EINVAL;
1175 spin_lock(&filp->f_lock);
1176 break;
1177 case SEEK_CUR:
1178 if (offset == 0)
1179 return filp->f_pos;
1180 spin_lock(&filp->f_lock);
1181 offset += filp->f_pos;
1182 if (offset < 0) {
1183 spin_unlock(&filp->f_lock);
1184 return -EINVAL;
1185 }
1186 }
1187 if (offset != filp->f_pos) {
1188 filp->f_pos = offset;
1189 if (nfs_readdir_use_cookie(filp))
1190 dir_ctx->dir_cookie = offset;
1191 else
1192 dir_ctx->dir_cookie = 0;
1193 if (offset == 0)
1194 memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf));
1195 dir_ctx->duped = 0;
1196 }
1197 spin_unlock(&filp->f_lock);
1198 return offset;
1199}
1200
1201/*
1202 * All directory operations under NFS are synchronous, so fsync()
1203 * is a dummy operation.
1204 */
1205static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end,
1206 int datasync)
1207{
1208 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync);
1209
1210 nfs_inc_stats(file_inode(filp), NFSIOS_VFSFSYNC);
1211 return 0;
1212}
1213
1214/**
1215 * nfs_force_lookup_revalidate - Mark the directory as having changed
1216 * @dir: pointer to directory inode
1217 *
1218 * This forces the revalidation code in nfs_lookup_revalidate() to do a
1219 * full lookup on all child dentries of 'dir' whenever a change occurs
1220 * on the server that might have invalidated our dcache.
1221 *
1222 * Note that we reserve bit '0' as a tag to let us know when a dentry
1223 * was revalidated while holding a delegation on its inode.
1224 *
1225 * The caller should be holding dir->i_lock
1226 */
1227void nfs_force_lookup_revalidate(struct inode *dir)
1228{
1229 NFS_I(dir)->cache_change_attribute += 2;
1230}
1231EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
1232
1233/**
1234 * nfs_verify_change_attribute - Detects NFS remote directory changes
1235 * @dir: pointer to parent directory inode
1236 * @verf: previously saved change attribute
1237 *
1238 * Return "false" if the verifiers doesn't match the change attribute.
1239 * This would usually indicate that the directory contents have changed on
1240 * the server, and that any dentries need revalidating.
1241 */
1242static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf)
1243{
1244 return (verf & ~1UL) == nfs_save_change_attribute(dir);
1245}
1246
1247static void nfs_set_verifier_delegated(unsigned long *verf)
1248{
1249 *verf |= 1UL;
1250}
1251
1252#if IS_ENABLED(CONFIG_NFS_V4)
1253static void nfs_unset_verifier_delegated(unsigned long *verf)
1254{
1255 *verf &= ~1UL;
1256}
1257#endif /* IS_ENABLED(CONFIG_NFS_V4) */
1258
1259static bool nfs_test_verifier_delegated(unsigned long verf)
1260{
1261 return verf & 1;
1262}
1263
1264static bool nfs_verifier_is_delegated(struct dentry *dentry)
1265{
1266 return nfs_test_verifier_delegated(dentry->d_time);
1267}
1268
1269static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf)
1270{
1271 struct inode *inode = d_inode(dentry);
1272
1273 if (!nfs_verifier_is_delegated(dentry) &&
1274 !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf))
1275 goto out;
1276 if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
1277 nfs_set_verifier_delegated(&verf);
1278out:
1279 dentry->d_time = verf;
1280}
1281
1282/**
1283 * nfs_set_verifier - save a parent directory verifier in the dentry
1284 * @dentry: pointer to dentry
1285 * @verf: verifier to save
1286 *
1287 * Saves the parent directory verifier in @dentry. If the inode has
1288 * a delegation, we also tag the dentry as having been revalidated
1289 * while holding a delegation so that we know we don't have to
1290 * look it up again after a directory change.
1291 */
1292void nfs_set_verifier(struct dentry *dentry, unsigned long verf)
1293{
1294
1295 spin_lock(&dentry->d_lock);
1296 nfs_set_verifier_locked(dentry, verf);
1297 spin_unlock(&dentry->d_lock);
1298}
1299EXPORT_SYMBOL_GPL(nfs_set_verifier);
1300
1301#if IS_ENABLED(CONFIG_NFS_V4)
1302/**
1303 * nfs_clear_verifier_delegated - clear the dir verifier delegation tag
1304 * @inode: pointer to inode
1305 *
1306 * Iterates through the dentries in the inode alias list and clears
1307 * the tag used to indicate that the dentry has been revalidated
1308 * while holding a delegation.
1309 * This function is intended for use when the delegation is being
1310 * returned or revoked.
1311 */
1312void nfs_clear_verifier_delegated(struct inode *inode)
1313{
1314 struct dentry *alias;
1315
1316 if (!inode)
1317 return;
1318 spin_lock(&inode->i_lock);
1319 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
1320 spin_lock(&alias->d_lock);
1321 nfs_unset_verifier_delegated(&alias->d_time);
1322 spin_unlock(&alias->d_lock);
1323 }
1324 spin_unlock(&inode->i_lock);
1325}
1326EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated);
1327#endif /* IS_ENABLED(CONFIG_NFS_V4) */
1328
1329/*
1330 * A check for whether or not the parent directory has changed.
1331 * In the case it has, we assume that the dentries are untrustworthy
1332 * and may need to be looked up again.
1333 * If rcu_walk prevents us from performing a full check, return 0.
1334 */
1335static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
1336 int rcu_walk)
1337{
1338 if (IS_ROOT(dentry))
1339 return 1;
1340 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
1341 return 0;
1342 if (!nfs_verify_change_attribute(dir, dentry->d_time))
1343 return 0;
1344 /* Revalidate nfsi->cache_change_attribute before we declare a match */
1345 if (nfs_mapping_need_revalidate_inode(dir)) {
1346 if (rcu_walk)
1347 return 0;
1348 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
1349 return 0;
1350 }
1351 if (!nfs_verify_change_attribute(dir, dentry->d_time))
1352 return 0;
1353 return 1;
1354}
1355
1356/*
1357 * Use intent information to check whether or not we're going to do
1358 * an O_EXCL create using this path component.
1359 */
1360static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags)
1361{
1362 if (NFS_PROTO(dir)->version == 2)
1363 return 0;
1364 return flags & LOOKUP_EXCL;
1365}
1366
1367/*
1368 * Inode and filehandle revalidation for lookups.
1369 *
1370 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
1371 * or if the intent information indicates that we're about to open this
1372 * particular file and the "nocto" mount flag is not set.
1373 *
1374 */
1375static
1376int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
1377{
1378 struct nfs_server *server = NFS_SERVER(inode);
1379 int ret;
1380
1381 if (IS_AUTOMOUNT(inode))
1382 return 0;
1383
1384 if (flags & LOOKUP_OPEN) {
1385 switch (inode->i_mode & S_IFMT) {
1386 case S_IFREG:
1387 /* A NFSv4 OPEN will revalidate later */
1388 if (server->caps & NFS_CAP_ATOMIC_OPEN)
1389 goto out;
1390 fallthrough;
1391 case S_IFDIR:
1392 if (server->flags & NFS_MOUNT_NOCTO)
1393 break;
1394 /* NFS close-to-open cache consistency validation */
1395 goto out_force;
1396 }
1397 }
1398
1399 /* VFS wants an on-the-wire revalidation */
1400 if (flags & LOOKUP_REVAL)
1401 goto out_force;
1402out:
1403 return (inode->i_nlink == 0) ? -ESTALE : 0;
1404out_force:
1405 if (flags & LOOKUP_RCU)
1406 return -ECHILD;
1407 ret = __nfs_revalidate_inode(server, inode);
1408 if (ret != 0)
1409 return ret;
1410 goto out;
1411}
1412
1413static void nfs_mark_dir_for_revalidate(struct inode *inode)
1414{
1415 spin_lock(&inode->i_lock);
1416 nfs_set_cache_invalid(inode, NFS_INO_REVAL_PAGECACHE);
1417 spin_unlock(&inode->i_lock);
1418}
1419
1420/*
1421 * We judge how long we want to trust negative
1422 * dentries by looking at the parent inode mtime.
1423 *
1424 * If parent mtime has changed, we revalidate, else we wait for a
1425 * period corresponding to the parent's attribute cache timeout value.
1426 *
1427 * If LOOKUP_RCU prevents us from performing a full check, return 1
1428 * suggesting a reval is needed.
1429 *
1430 * Note that when creating a new file, or looking up a rename target,
1431 * then it shouldn't be necessary to revalidate a negative dentry.
1432 */
1433static inline
1434int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
1435 unsigned int flags)
1436{
1437 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
1438 return 0;
1439 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)
1440 return 1;
1441 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU);
1442}
1443
1444static int
1445nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
1446 struct inode *inode, int error)
1447{
1448 switch (error) {
1449 case 1:
1450 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
1451 __func__, dentry);
1452 return 1;
1453 case 0:
1454 /*
1455 * We can't d_drop the root of a disconnected tree:
1456 * its d_hash is on the s_anon list and d_drop() would hide
1457 * it from shrink_dcache_for_unmount(), leading to busy
1458 * inodes on unmount and further oopses.
1459 */
1460 if (inode && IS_ROOT(dentry))
1461 return 1;
1462 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
1463 __func__, dentry);
1464 return 0;
1465 }
1466 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
1467 __func__, dentry, error);
1468 return error;
1469}
1470
1471static int
1472nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry,
1473 unsigned int flags)
1474{
1475 int ret = 1;
1476 if (nfs_neg_need_reval(dir, dentry, flags)) {
1477 if (flags & LOOKUP_RCU)
1478 return -ECHILD;
1479 ret = 0;
1480 }
1481 return nfs_lookup_revalidate_done(dir, dentry, NULL, ret);
1482}
1483
1484static int
1485nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
1486 struct inode *inode)
1487{
1488 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1489 return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1490}
1491
1492static int
1493nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
1494 struct inode *inode)
1495{
1496 struct nfs_fh *fhandle;
1497 struct nfs_fattr *fattr;
1498 struct nfs4_label *label;
1499 unsigned long dir_verifier;
1500 int ret;
1501
1502 ret = -ENOMEM;
1503 fhandle = nfs_alloc_fhandle();
1504 fattr = nfs_alloc_fattr();
1505 label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL);
1506 if (fhandle == NULL || fattr == NULL || IS_ERR(label))
1507 goto out;
1508
1509 dir_verifier = nfs_save_change_attribute(dir);
1510 ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
1511 if (ret < 0) {
1512 switch (ret) {
1513 case -ESTALE:
1514 case -ENOENT:
1515 ret = 0;
1516 break;
1517 case -ETIMEDOUT:
1518 if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
1519 ret = 1;
1520 }
1521 goto out;
1522 }
1523 ret = 0;
1524 if (nfs_compare_fh(NFS_FH(inode), fhandle))
1525 goto out;
1526 if (nfs_refresh_inode(inode, fattr) < 0)
1527 goto out;
1528
1529 nfs_setsecurity(inode, fattr, label);
1530 nfs_set_verifier(dentry, dir_verifier);
1531
1532 /* set a readdirplus hint that we had a cache miss */
1533 nfs_force_use_readdirplus(dir);
1534 ret = 1;
1535out:
1536 nfs_free_fattr(fattr);
1537 nfs_free_fhandle(fhandle);
1538 nfs4_label_free(label);
1539
1540 /*
1541 * If the lookup failed despite the dentry change attribute being
1542 * a match, then we should revalidate the directory cache.
1543 */
1544 if (!ret && nfs_verify_change_attribute(dir, dentry->d_time))
1545 nfs_mark_dir_for_revalidate(dir);
1546 return nfs_lookup_revalidate_done(dir, dentry, inode, ret);
1547}
1548
1549/*
1550 * This is called every time the dcache has a lookup hit,
1551 * and we should check whether we can really trust that
1552 * lookup.
1553 *
1554 * NOTE! The hit can be a negative hit too, don't assume
1555 * we have an inode!
1556 *
1557 * If the parent directory is seen to have changed, we throw out the
1558 * cached dentry and do a new lookup.
1559 */
1560static int
1561nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
1562 unsigned int flags)
1563{
1564 struct inode *inode;
1565 int error;
1566
1567 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
1568 inode = d_inode(dentry);
1569
1570 if (!inode)
1571 return nfs_lookup_revalidate_negative(dir, dentry, flags);
1572
1573 if (is_bad_inode(inode)) {
1574 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1575 __func__, dentry);
1576 goto out_bad;
1577 }
1578
1579 if (nfs_verifier_is_delegated(dentry))
1580 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
1581
1582 /* Force a full look up iff the parent directory has changed */
1583 if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
1584 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
1585 error = nfs_lookup_verify_inode(inode, flags);
1586 if (error) {
1587 if (error == -ESTALE)
1588 nfs_mark_dir_for_revalidate(dir);
1589 goto out_bad;
1590 }
1591 nfs_advise_use_readdirplus(dir);
1592 goto out_valid;
1593 }
1594
1595 if (flags & LOOKUP_RCU)
1596 return -ECHILD;
1597
1598 if (NFS_STALE(inode))
1599 goto out_bad;
1600
1601 trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
1602 error = nfs_lookup_revalidate_dentry(dir, dentry, inode);
1603 trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
1604 return error;
1605out_valid:
1606 return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1607out_bad:
1608 if (flags & LOOKUP_RCU)
1609 return -ECHILD;
1610 return nfs_lookup_revalidate_done(dir, dentry, inode, 0);
1611}
1612
1613static int
1614__nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags,
1615 int (*reval)(struct inode *, struct dentry *, unsigned int))
1616{
1617 struct dentry *parent;
1618 struct inode *dir;
1619 int ret;
1620
1621 if (flags & LOOKUP_RCU) {
1622 parent = READ_ONCE(dentry->d_parent);
1623 dir = d_inode_rcu(parent);
1624 if (!dir)
1625 return -ECHILD;
1626 ret = reval(dir, dentry, flags);
1627 if (parent != READ_ONCE(dentry->d_parent))
1628 return -ECHILD;
1629 } else {
1630 parent = dget_parent(dentry);
1631 ret = reval(d_inode(parent), dentry, flags);
1632 dput(parent);
1633 }
1634 return ret;
1635}
1636
1637static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
1638{
1639 return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate);
1640}
1641
1642/*
1643 * A weaker form of d_revalidate for revalidating just the d_inode(dentry)
1644 * when we don't really care about the dentry name. This is called when a
1645 * pathwalk ends on a dentry that was not found via a normal lookup in the
1646 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals).
1647 *
1648 * In this situation, we just want to verify that the inode itself is OK
1649 * since the dentry might have changed on the server.
1650 */
1651static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags)
1652{
1653 struct inode *inode = d_inode(dentry);
1654 int error = 0;
1655
1656 /*
1657 * I believe we can only get a negative dentry here in the case of a
1658 * procfs-style symlink. Just assume it's correct for now, but we may
1659 * eventually need to do something more here.
1660 */
1661 if (!inode) {
1662 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n",
1663 __func__, dentry);
1664 return 1;
1665 }
1666
1667 if (is_bad_inode(inode)) {
1668 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1669 __func__, dentry);
1670 return 0;
1671 }
1672
1673 error = nfs_lookup_verify_inode(inode, flags);
1674 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n",
1675 __func__, inode->i_ino, error ? "invalid" : "valid");
1676 return !error;
1677}
1678
1679/*
1680 * This is called from dput() when d_count is going to 0.
1681 */
1682static int nfs_dentry_delete(const struct dentry *dentry)
1683{
1684 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n",
1685 dentry, dentry->d_flags);
1686
1687 /* Unhash any dentry with a stale inode */
1688 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry)))
1689 return 1;
1690
1691 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1692 /* Unhash it, so that ->d_iput() would be called */
1693 return 1;
1694 }
1695 if (!(dentry->d_sb->s_flags & SB_ACTIVE)) {
1696 /* Unhash it, so that ancestors of killed async unlink
1697 * files will be cleaned up during umount */
1698 return 1;
1699 }
1700 return 0;
1701
1702}
1703
1704/* Ensure that we revalidate inode->i_nlink */
1705static void nfs_drop_nlink(struct inode *inode)
1706{
1707 spin_lock(&inode->i_lock);
1708 /* drop the inode if we're reasonably sure this is the last link */
1709 if (inode->i_nlink > 0)
1710 drop_nlink(inode);
1711 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
1712 nfs_set_cache_invalid(
1713 inode, NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME |
1714 NFS_INO_INVALID_NLINK);
1715 spin_unlock(&inode->i_lock);
1716}
1717
1718/*
1719 * Called when the dentry loses inode.
1720 * We use it to clean up silly-renamed files.
1721 */
1722static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
1723{
1724 if (S_ISDIR(inode->i_mode))
1725 /* drop any readdir cache as it could easily be old */
1726 nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA);
1727
1728 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1729 nfs_complete_unlink(dentry, inode);
1730 nfs_drop_nlink(inode);
1731 }
1732 iput(inode);
1733}
1734
1735static void nfs_d_release(struct dentry *dentry)
1736{
1737 /* free cached devname value, if it survived that far */
1738 if (unlikely(dentry->d_fsdata)) {
1739 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
1740 WARN_ON(1);
1741 else
1742 kfree(dentry->d_fsdata);
1743 }
1744}
1745
1746const struct dentry_operations nfs_dentry_operations = {
1747 .d_revalidate = nfs_lookup_revalidate,
1748 .d_weak_revalidate = nfs_weak_revalidate,
1749 .d_delete = nfs_dentry_delete,
1750 .d_iput = nfs_dentry_iput,
1751 .d_automount = nfs_d_automount,
1752 .d_release = nfs_d_release,
1753};
1754EXPORT_SYMBOL_GPL(nfs_dentry_operations);
1755
1756struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
1757{
1758 struct dentry *res;
1759 struct inode *inode = NULL;
1760 struct nfs_fh *fhandle = NULL;
1761 struct nfs_fattr *fattr = NULL;
1762 struct nfs4_label *label = NULL;
1763 unsigned long dir_verifier;
1764 int error;
1765
1766 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry);
1767 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
1768
1769 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen))
1770 return ERR_PTR(-ENAMETOOLONG);
1771
1772 /*
1773 * If we're doing an exclusive create, optimize away the lookup
1774 * but don't hash the dentry.
1775 */
1776 if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET)
1777 return NULL;
1778
1779 res = ERR_PTR(-ENOMEM);
1780 fhandle = nfs_alloc_fhandle();
1781 fattr = nfs_alloc_fattr();
1782 if (fhandle == NULL || fattr == NULL)
1783 goto out;
1784
1785 label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT);
1786 if (IS_ERR(label))
1787 goto out;
1788
1789 dir_verifier = nfs_save_change_attribute(dir);
1790 trace_nfs_lookup_enter(dir, dentry, flags);
1791 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
1792 if (error == -ENOENT)
1793 goto no_entry;
1794 if (error < 0) {
1795 res = ERR_PTR(error);
1796 goto out_label;
1797 }
1798 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
1799 res = ERR_CAST(inode);
1800 if (IS_ERR(res))
1801 goto out_label;
1802
1803 /* Notify readdir to use READDIRPLUS */
1804 nfs_force_use_readdirplus(dir);
1805
1806no_entry:
1807 res = d_splice_alias(inode, dentry);
1808 if (res != NULL) {
1809 if (IS_ERR(res))
1810 goto out_label;
1811 dentry = res;
1812 }
1813 nfs_set_verifier(dentry, dir_verifier);
1814out_label:
1815 trace_nfs_lookup_exit(dir, dentry, flags, error);
1816 nfs4_label_free(label);
1817out:
1818 nfs_free_fattr(fattr);
1819 nfs_free_fhandle(fhandle);
1820 return res;
1821}
1822EXPORT_SYMBOL_GPL(nfs_lookup);
1823
1824#if IS_ENABLED(CONFIG_NFS_V4)
1825static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
1826
1827const struct dentry_operations nfs4_dentry_operations = {
1828 .d_revalidate = nfs4_lookup_revalidate,
1829 .d_weak_revalidate = nfs_weak_revalidate,
1830 .d_delete = nfs_dentry_delete,
1831 .d_iput = nfs_dentry_iput,
1832 .d_automount = nfs_d_automount,
1833 .d_release = nfs_d_release,
1834};
1835EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
1836
1837static fmode_t flags_to_mode(int flags)
1838{
1839 fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
1840 if ((flags & O_ACCMODE) != O_WRONLY)
1841 res |= FMODE_READ;
1842 if ((flags & O_ACCMODE) != O_RDONLY)
1843 res |= FMODE_WRITE;
1844 return res;
1845}
1846
1847static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
1848{
1849 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
1850}
1851
1852static int do_open(struct inode *inode, struct file *filp)
1853{
1854 nfs_fscache_open_file(inode, filp);
1855 return 0;
1856}
1857
1858static int nfs_finish_open(struct nfs_open_context *ctx,
1859 struct dentry *dentry,
1860 struct file *file, unsigned open_flags)
1861{
1862 int err;
1863
1864 err = finish_open(file, dentry, do_open);
1865 if (err)
1866 goto out;
1867 if (S_ISREG(file->f_path.dentry->d_inode->i_mode))
1868 nfs_file_set_open_context(file, ctx);
1869 else
1870 err = -EOPENSTALE;
1871out:
1872 return err;
1873}
1874
1875int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
1876 struct file *file, unsigned open_flags,
1877 umode_t mode)
1878{
1879 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1880 struct nfs_open_context *ctx;
1881 struct dentry *res;
1882 struct iattr attr = { .ia_valid = ATTR_OPEN };
1883 struct inode *inode;
1884 unsigned int lookup_flags = 0;
1885 bool switched = false;
1886 int created = 0;
1887 int err;
1888
1889 /* Expect a negative dentry */
1890 BUG_ON(d_inode(dentry));
1891
1892 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n",
1893 dir->i_sb->s_id, dir->i_ino, dentry);
1894
1895 err = nfs_check_flags(open_flags);
1896 if (err)
1897 return err;
1898
1899 /* NFS only supports OPEN on regular files */
1900 if ((open_flags & O_DIRECTORY)) {
1901 if (!d_in_lookup(dentry)) {
1902 /*
1903 * Hashed negative dentry with O_DIRECTORY: dentry was
1904 * revalidated and is fine, no need to perform lookup
1905 * again
1906 */
1907 return -ENOENT;
1908 }
1909 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY;
1910 goto no_open;
1911 }
1912
1913 if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
1914 return -ENAMETOOLONG;
1915
1916 if (open_flags & O_CREAT) {
1917 struct nfs_server *server = NFS_SERVER(dir);
1918
1919 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
1920 mode &= ~current_umask();
1921
1922 attr.ia_valid |= ATTR_MODE;
1923 attr.ia_mode = mode;
1924 }
1925 if (open_flags & O_TRUNC) {
1926 attr.ia_valid |= ATTR_SIZE;
1927 attr.ia_size = 0;
1928 }
1929
1930 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) {
1931 d_drop(dentry);
1932 switched = true;
1933 dentry = d_alloc_parallel(dentry->d_parent,
1934 &dentry->d_name, &wq);
1935 if (IS_ERR(dentry))
1936 return PTR_ERR(dentry);
1937 if (unlikely(!d_in_lookup(dentry)))
1938 return finish_no_open(file, dentry);
1939 }
1940
1941 ctx = create_nfs_open_context(dentry, open_flags, file);
1942 err = PTR_ERR(ctx);
1943 if (IS_ERR(ctx))
1944 goto out;
1945
1946 trace_nfs_atomic_open_enter(dir, ctx, open_flags);
1947 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created);
1948 if (created)
1949 file->f_mode |= FMODE_CREATED;
1950 if (IS_ERR(inode)) {
1951 err = PTR_ERR(inode);
1952 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
1953 put_nfs_open_context(ctx);
1954 d_drop(dentry);
1955 switch (err) {
1956 case -ENOENT:
1957 d_splice_alias(NULL, dentry);
1958 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1959 break;
1960 case -EISDIR:
1961 case -ENOTDIR:
1962 goto no_open;
1963 case -ELOOP:
1964 if (!(open_flags & O_NOFOLLOW))
1965 goto no_open;
1966 break;
1967 /* case -EINVAL: */
1968 default:
1969 break;
1970 }
1971 goto out;
1972 }
1973
1974 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags);
1975 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
1976 put_nfs_open_context(ctx);
1977out:
1978 if (unlikely(switched)) {
1979 d_lookup_done(dentry);
1980 dput(dentry);
1981 }
1982 return err;
1983
1984no_open:
1985 res = nfs_lookup(dir, dentry, lookup_flags);
1986 if (switched) {
1987 d_lookup_done(dentry);
1988 if (!res)
1989 res = dentry;
1990 else
1991 dput(dentry);
1992 }
1993 if (IS_ERR(res))
1994 return PTR_ERR(res);
1995 return finish_no_open(file, res);
1996}
1997EXPORT_SYMBOL_GPL(nfs_atomic_open);
1998
1999static int
2000nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
2001 unsigned int flags)
2002{
2003 struct inode *inode;
2004
2005 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
2006 goto full_reval;
2007 if (d_mountpoint(dentry))
2008 goto full_reval;
2009
2010 inode = d_inode(dentry);
2011
2012 /* We can't create new files in nfs_open_revalidate(), so we
2013 * optimize away revalidation of negative dentries.
2014 */
2015 if (inode == NULL)
2016 goto full_reval;
2017
2018 if (nfs_verifier_is_delegated(dentry))
2019 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
2020
2021 /* NFS only supports OPEN on regular files */
2022 if (!S_ISREG(inode->i_mode))
2023 goto full_reval;
2024
2025 /* We cannot do exclusive creation on a positive dentry */
2026 if (flags & (LOOKUP_EXCL | LOOKUP_REVAL))
2027 goto reval_dentry;
2028
2029 /* Check if the directory changed */
2030 if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU))
2031 goto reval_dentry;
2032
2033 /* Let f_op->open() actually open (and revalidate) the file */
2034 return 1;
2035reval_dentry:
2036 if (flags & LOOKUP_RCU)
2037 return -ECHILD;
2038 return nfs_lookup_revalidate_dentry(dir, dentry, inode);
2039
2040full_reval:
2041 return nfs_do_lookup_revalidate(dir, dentry, flags);
2042}
2043
2044static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
2045{
2046 return __nfs_lookup_revalidate(dentry, flags,
2047 nfs4_do_lookup_revalidate);
2048}
2049
2050#endif /* CONFIG_NFSV4 */
2051
2052struct dentry *
2053nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle,
2054 struct nfs_fattr *fattr,
2055 struct nfs4_label *label)
2056{
2057 struct dentry *parent = dget_parent(dentry);
2058 struct inode *dir = d_inode(parent);
2059 struct inode *inode;
2060 struct dentry *d;
2061 int error;
2062
2063 d_drop(dentry);
2064
2065 if (fhandle->size == 0) {
2066 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, NULL);
2067 if (error)
2068 goto out_error;
2069 }
2070 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2071 if (!(fattr->valid & NFS_ATTR_FATTR)) {
2072 struct nfs_server *server = NFS_SB(dentry->d_sb);
2073 error = server->nfs_client->rpc_ops->getattr(server, fhandle,
2074 fattr, NULL, NULL);
2075 if (error < 0)
2076 goto out_error;
2077 }
2078 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
2079 d = d_splice_alias(inode, dentry);
2080out:
2081 dput(parent);
2082 return d;
2083out_error:
2084 d = ERR_PTR(error);
2085 goto out;
2086}
2087EXPORT_SYMBOL_GPL(nfs_add_or_obtain);
2088
2089/*
2090 * Code common to create, mkdir, and mknod.
2091 */
2092int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
2093 struct nfs_fattr *fattr,
2094 struct nfs4_label *label)
2095{
2096 struct dentry *d;
2097
2098 d = nfs_add_or_obtain(dentry, fhandle, fattr, label);
2099 if (IS_ERR(d))
2100 return PTR_ERR(d);
2101
2102 /* Callers don't care */
2103 dput(d);
2104 return 0;
2105}
2106EXPORT_SYMBOL_GPL(nfs_instantiate);
2107
2108/*
2109 * Following a failed create operation, we drop the dentry rather
2110 * than retain a negative dentry. This avoids a problem in the event
2111 * that the operation succeeded on the server, but an error in the
2112 * reply path made it appear to have failed.
2113 */
2114int nfs_create(struct user_namespace *mnt_userns, struct inode *dir,
2115 struct dentry *dentry, umode_t mode, bool excl)
2116{
2117 struct iattr attr;
2118 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT;
2119 int error;
2120
2121 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n",
2122 dir->i_sb->s_id, dir->i_ino, dentry);
2123
2124 attr.ia_mode = mode;
2125 attr.ia_valid = ATTR_MODE;
2126
2127 trace_nfs_create_enter(dir, dentry, open_flags);
2128 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
2129 trace_nfs_create_exit(dir, dentry, open_flags, error);
2130 if (error != 0)
2131 goto out_err;
2132 return 0;
2133out_err:
2134 d_drop(dentry);
2135 return error;
2136}
2137EXPORT_SYMBOL_GPL(nfs_create);
2138
2139/*
2140 * See comments for nfs_proc_create regarding failed operations.
2141 */
2142int
2143nfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
2144 struct dentry *dentry, umode_t mode, dev_t rdev)
2145{
2146 struct iattr attr;
2147 int status;
2148
2149 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n",
2150 dir->i_sb->s_id, dir->i_ino, dentry);
2151
2152 attr.ia_mode = mode;
2153 attr.ia_valid = ATTR_MODE;
2154
2155 trace_nfs_mknod_enter(dir, dentry);
2156 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
2157 trace_nfs_mknod_exit(dir, dentry, status);
2158 if (status != 0)
2159 goto out_err;
2160 return 0;
2161out_err:
2162 d_drop(dentry);
2163 return status;
2164}
2165EXPORT_SYMBOL_GPL(nfs_mknod);
2166
2167/*
2168 * See comments for nfs_proc_create regarding failed operations.
2169 */
2170int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
2171 struct dentry *dentry, umode_t mode)
2172{
2173 struct iattr attr;
2174 int error;
2175
2176 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n",
2177 dir->i_sb->s_id, dir->i_ino, dentry);
2178
2179 attr.ia_valid = ATTR_MODE;
2180 attr.ia_mode = mode | S_IFDIR;
2181
2182 trace_nfs_mkdir_enter(dir, dentry);
2183 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
2184 trace_nfs_mkdir_exit(dir, dentry, error);
2185 if (error != 0)
2186 goto out_err;
2187 return 0;
2188out_err:
2189 d_drop(dentry);
2190 return error;
2191}
2192EXPORT_SYMBOL_GPL(nfs_mkdir);
2193
2194static void nfs_dentry_handle_enoent(struct dentry *dentry)
2195{
2196 if (simple_positive(dentry))
2197 d_delete(dentry);
2198}
2199
2200int nfs_rmdir(struct inode *dir, struct dentry *dentry)
2201{
2202 int error;
2203
2204 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n",
2205 dir->i_sb->s_id, dir->i_ino, dentry);
2206
2207 trace_nfs_rmdir_enter(dir, dentry);
2208 if (d_really_is_positive(dentry)) {
2209 down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
2210 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
2211 /* Ensure the VFS deletes this inode */
2212 switch (error) {
2213 case 0:
2214 clear_nlink(d_inode(dentry));
2215 break;
2216 case -ENOENT:
2217 nfs_dentry_handle_enoent(dentry);
2218 }
2219 up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
2220 } else
2221 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
2222 trace_nfs_rmdir_exit(dir, dentry, error);
2223
2224 return error;
2225}
2226EXPORT_SYMBOL_GPL(nfs_rmdir);
2227
2228/*
2229 * Remove a file after making sure there are no pending writes,
2230 * and after checking that the file has only one user.
2231 *
2232 * We invalidate the attribute cache and free the inode prior to the operation
2233 * to avoid possible races if the server reuses the inode.
2234 */
2235static int nfs_safe_remove(struct dentry *dentry)
2236{
2237 struct inode *dir = d_inode(dentry->d_parent);
2238 struct inode *inode = d_inode(dentry);
2239 int error = -EBUSY;
2240
2241 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry);
2242
2243 /* If the dentry was sillyrenamed, we simply call d_delete() */
2244 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
2245 error = 0;
2246 goto out;
2247 }
2248
2249 trace_nfs_remove_enter(dir, dentry);
2250 if (inode != NULL) {
2251 error = NFS_PROTO(dir)->remove(dir, dentry);
2252 if (error == 0)
2253 nfs_drop_nlink(inode);
2254 } else
2255 error = NFS_PROTO(dir)->remove(dir, dentry);
2256 if (error == -ENOENT)
2257 nfs_dentry_handle_enoent(dentry);
2258 trace_nfs_remove_exit(dir, dentry, error);
2259out:
2260 return error;
2261}
2262
2263/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
2264 * belongs to an active ".nfs..." file and we return -EBUSY.
2265 *
2266 * If sillyrename() returns 0, we do nothing, otherwise we unlink.
2267 */
2268int nfs_unlink(struct inode *dir, struct dentry *dentry)
2269{
2270 int error;
2271 int need_rehash = 0;
2272
2273 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id,
2274 dir->i_ino, dentry);
2275
2276 trace_nfs_unlink_enter(dir, dentry);
2277 spin_lock(&dentry->d_lock);
2278 if (d_count(dentry) > 1) {
2279 spin_unlock(&dentry->d_lock);
2280 /* Start asynchronous writeout of the inode */
2281 write_inode_now(d_inode(dentry), 0);
2282 error = nfs_sillyrename(dir, dentry);
2283 goto out;
2284 }
2285 if (!d_unhashed(dentry)) {
2286 __d_drop(dentry);
2287 need_rehash = 1;
2288 }
2289 spin_unlock(&dentry->d_lock);
2290 error = nfs_safe_remove(dentry);
2291 if (!error || error == -ENOENT) {
2292 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2293 } else if (need_rehash)
2294 d_rehash(dentry);
2295out:
2296 trace_nfs_unlink_exit(dir, dentry, error);
2297 return error;
2298}
2299EXPORT_SYMBOL_GPL(nfs_unlink);
2300
2301/*
2302 * To create a symbolic link, most file systems instantiate a new inode,
2303 * add a page to it containing the path, then write it out to the disk
2304 * using prepare_write/commit_write.
2305 *
2306 * Unfortunately the NFS client can't create the in-core inode first
2307 * because it needs a file handle to create an in-core inode (see
2308 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the
2309 * symlink request has completed on the server.
2310 *
2311 * So instead we allocate a raw page, copy the symname into it, then do
2312 * the SYMLINK request with the page as the buffer. If it succeeds, we
2313 * now have a new file handle and can instantiate an in-core NFS inode
2314 * and move the raw page into its mapping.
2315 */
2316int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
2317 struct dentry *dentry, const char *symname)
2318{
2319 struct page *page;
2320 char *kaddr;
2321 struct iattr attr;
2322 unsigned int pathlen = strlen(symname);
2323 int error;
2324
2325 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id,
2326 dir->i_ino, dentry, symname);
2327
2328 if (pathlen > PAGE_SIZE)
2329 return -ENAMETOOLONG;
2330
2331 attr.ia_mode = S_IFLNK | S_IRWXUGO;
2332 attr.ia_valid = ATTR_MODE;
2333
2334 page = alloc_page(GFP_USER);
2335 if (!page)
2336 return -ENOMEM;
2337
2338 kaddr = page_address(page);
2339 memcpy(kaddr, symname, pathlen);
2340 if (pathlen < PAGE_SIZE)
2341 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
2342
2343 trace_nfs_symlink_enter(dir, dentry);
2344 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
2345 trace_nfs_symlink_exit(dir, dentry, error);
2346 if (error != 0) {
2347 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n",
2348 dir->i_sb->s_id, dir->i_ino,
2349 dentry, symname, error);
2350 d_drop(dentry);
2351 __free_page(page);
2352 return error;
2353 }
2354
2355 /*
2356 * No big deal if we can't add this page to the page cache here.
2357 * READLINK will get the missing page from the server if needed.
2358 */
2359 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0,
2360 GFP_KERNEL)) {
2361 SetPageUptodate(page);
2362 unlock_page(page);
2363 /*
2364 * add_to_page_cache_lru() grabs an extra page refcount.
2365 * Drop it here to avoid leaking this page later.
2366 */
2367 put_page(page);
2368 } else
2369 __free_page(page);
2370
2371 return 0;
2372}
2373EXPORT_SYMBOL_GPL(nfs_symlink);
2374
2375int
2376nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
2377{
2378 struct inode *inode = d_inode(old_dentry);
2379 int error;
2380
2381 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n",
2382 old_dentry, dentry);
2383
2384 trace_nfs_link_enter(inode, dir, dentry);
2385 d_drop(dentry);
2386 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
2387 if (error == 0) {
2388 ihold(inode);
2389 d_add(dentry, inode);
2390 }
2391 trace_nfs_link_exit(inode, dir, dentry, error);
2392 return error;
2393}
2394EXPORT_SYMBOL_GPL(nfs_link);
2395
2396/*
2397 * RENAME
2398 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
2399 * different file handle for the same inode after a rename (e.g. when
2400 * moving to a different directory). A fail-safe method to do so would
2401 * be to look up old_dir/old_name, create a link to new_dir/new_name and
2402 * rename the old file using the sillyrename stuff. This way, the original
2403 * file in old_dir will go away when the last process iput()s the inode.
2404 *
2405 * FIXED.
2406 *
2407 * It actually works quite well. One needs to have the possibility for
2408 * at least one ".nfs..." file in each directory the file ever gets
2409 * moved or linked to which happens automagically with the new
2410 * implementation that only depends on the dcache stuff instead of
2411 * using the inode layer
2412 *
2413 * Unfortunately, things are a little more complicated than indicated
2414 * above. For a cross-directory move, we want to make sure we can get
2415 * rid of the old inode after the operation. This means there must be
2416 * no pending writes (if it's a file), and the use count must be 1.
2417 * If these conditions are met, we can drop the dentries before doing
2418 * the rename.
2419 */
2420int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
2421 struct dentry *old_dentry, struct inode *new_dir,
2422 struct dentry *new_dentry, unsigned int flags)
2423{
2424 struct inode *old_inode = d_inode(old_dentry);
2425 struct inode *new_inode = d_inode(new_dentry);
2426 struct dentry *dentry = NULL, *rehash = NULL;
2427 struct rpc_task *task;
2428 int error = -EBUSY;
2429
2430 if (flags)
2431 return -EINVAL;
2432
2433 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n",
2434 old_dentry, new_dentry,
2435 d_count(new_dentry));
2436
2437 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry);
2438 /*
2439 * For non-directories, check whether the target is busy and if so,
2440 * make a copy of the dentry and then do a silly-rename. If the
2441 * silly-rename succeeds, the copied dentry is hashed and becomes
2442 * the new target.
2443 */
2444 if (new_inode && !S_ISDIR(new_inode->i_mode)) {
2445 /*
2446 * To prevent any new references to the target during the
2447 * rename, we unhash the dentry in advance.
2448 */
2449 if (!d_unhashed(new_dentry)) {
2450 d_drop(new_dentry);
2451 rehash = new_dentry;
2452 }
2453
2454 if (d_count(new_dentry) > 2) {
2455 int err;
2456
2457 /* copy the target dentry's name */
2458 dentry = d_alloc(new_dentry->d_parent,
2459 &new_dentry->d_name);
2460 if (!dentry)
2461 goto out;
2462
2463 /* silly-rename the existing target ... */
2464 err = nfs_sillyrename(new_dir, new_dentry);
2465 if (err)
2466 goto out;
2467
2468 new_dentry = dentry;
2469 rehash = NULL;
2470 new_inode = NULL;
2471 }
2472 }
2473
2474 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL);
2475 if (IS_ERR(task)) {
2476 error = PTR_ERR(task);
2477 goto out;
2478 }
2479
2480 error = rpc_wait_for_completion_task(task);
2481 if (error != 0) {
2482 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1;
2483 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */
2484 smp_wmb();
2485 } else
2486 error = task->tk_status;
2487 rpc_put_task(task);
2488 /* Ensure the inode attributes are revalidated */
2489 if (error == 0) {
2490 spin_lock(&old_inode->i_lock);
2491 NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter();
2492 nfs_set_cache_invalid(old_inode, NFS_INO_INVALID_CHANGE |
2493 NFS_INO_INVALID_CTIME |
2494 NFS_INO_REVAL_FORCED);
2495 spin_unlock(&old_inode->i_lock);
2496 }
2497out:
2498 if (rehash)
2499 d_rehash(rehash);
2500 trace_nfs_rename_exit(old_dir, old_dentry,
2501 new_dir, new_dentry, error);
2502 if (!error) {
2503 if (new_inode != NULL)
2504 nfs_drop_nlink(new_inode);
2505 /*
2506 * The d_move() should be here instead of in an async RPC completion
2507 * handler because we need the proper locks to move the dentry. If
2508 * we're interrupted by a signal, the async RPC completion handler
2509 * should mark the directories for revalidation.
2510 */
2511 d_move(old_dentry, new_dentry);
2512 nfs_set_verifier(old_dentry,
2513 nfs_save_change_attribute(new_dir));
2514 } else if (error == -ENOENT)
2515 nfs_dentry_handle_enoent(old_dentry);
2516
2517 /* new dentry created? */
2518 if (dentry)
2519 dput(dentry);
2520 return error;
2521}
2522EXPORT_SYMBOL_GPL(nfs_rename);
2523
2524static DEFINE_SPINLOCK(nfs_access_lru_lock);
2525static LIST_HEAD(nfs_access_lru_list);
2526static atomic_long_t nfs_access_nr_entries;
2527
2528static unsigned long nfs_access_max_cachesize = 4*1024*1024;
2529module_param(nfs_access_max_cachesize, ulong, 0644);
2530MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length");
2531
2532static void nfs_access_free_entry(struct nfs_access_entry *entry)
2533{
2534 put_cred(entry->cred);
2535 kfree_rcu(entry, rcu_head);
2536 smp_mb__before_atomic();
2537 atomic_long_dec(&nfs_access_nr_entries);
2538 smp_mb__after_atomic();
2539}
2540
2541static void nfs_access_free_list(struct list_head *head)
2542{
2543 struct nfs_access_entry *cache;
2544
2545 while (!list_empty(head)) {
2546 cache = list_entry(head->next, struct nfs_access_entry, lru);
2547 list_del(&cache->lru);
2548 nfs_access_free_entry(cache);
2549 }
2550}
2551
2552static unsigned long
2553nfs_do_access_cache_scan(unsigned int nr_to_scan)
2554{
2555 LIST_HEAD(head);
2556 struct nfs_inode *nfsi, *next;
2557 struct nfs_access_entry *cache;
2558 long freed = 0;
2559
2560 spin_lock(&nfs_access_lru_lock);
2561 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) {
2562 struct inode *inode;
2563
2564 if (nr_to_scan-- == 0)
2565 break;
2566 inode = &nfsi->vfs_inode;
2567 spin_lock(&inode->i_lock);
2568 if (list_empty(&nfsi->access_cache_entry_lru))
2569 goto remove_lru_entry;
2570 cache = list_entry(nfsi->access_cache_entry_lru.next,
2571 struct nfs_access_entry, lru);
2572 list_move(&cache->lru, &head);
2573 rb_erase(&cache->rb_node, &nfsi->access_cache);
2574 freed++;
2575 if (!list_empty(&nfsi->access_cache_entry_lru))
2576 list_move_tail(&nfsi->access_cache_inode_lru,
2577 &nfs_access_lru_list);
2578 else {
2579remove_lru_entry:
2580 list_del_init(&nfsi->access_cache_inode_lru);
2581 smp_mb__before_atomic();
2582 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
2583 smp_mb__after_atomic();
2584 }
2585 spin_unlock(&inode->i_lock);
2586 }
2587 spin_unlock(&nfs_access_lru_lock);
2588 nfs_access_free_list(&head);
2589 return freed;
2590}
2591
2592unsigned long
2593nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
2594{
2595 int nr_to_scan = sc->nr_to_scan;
2596 gfp_t gfp_mask = sc->gfp_mask;
2597
2598 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
2599 return SHRINK_STOP;
2600 return nfs_do_access_cache_scan(nr_to_scan);
2601}
2602
2603
2604unsigned long
2605nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc)
2606{
2607 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries));
2608}
2609
2610static void
2611nfs_access_cache_enforce_limit(void)
2612{
2613 long nr_entries = atomic_long_read(&nfs_access_nr_entries);
2614 unsigned long diff;
2615 unsigned int nr_to_scan;
2616
2617 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize)
2618 return;
2619 nr_to_scan = 100;
2620 diff = nr_entries - nfs_access_max_cachesize;
2621 if (diff < nr_to_scan)
2622 nr_to_scan = diff;
2623 nfs_do_access_cache_scan(nr_to_scan);
2624}
2625
2626static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head)
2627{
2628 struct rb_root *root_node = &nfsi->access_cache;
2629 struct rb_node *n;
2630 struct nfs_access_entry *entry;
2631
2632 /* Unhook entries from the cache */
2633 while ((n = rb_first(root_node)) != NULL) {
2634 entry = rb_entry(n, struct nfs_access_entry, rb_node);
2635 rb_erase(n, root_node);
2636 list_move(&entry->lru, head);
2637 }
2638 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
2639}
2640
2641void nfs_access_zap_cache(struct inode *inode)
2642{
2643 LIST_HEAD(head);
2644
2645 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0)
2646 return;
2647 /* Remove from global LRU init */
2648 spin_lock(&nfs_access_lru_lock);
2649 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
2650 list_del_init(&NFS_I(inode)->access_cache_inode_lru);
2651
2652 spin_lock(&inode->i_lock);
2653 __nfs_access_zap_cache(NFS_I(inode), &head);
2654 spin_unlock(&inode->i_lock);
2655 spin_unlock(&nfs_access_lru_lock);
2656 nfs_access_free_list(&head);
2657}
2658EXPORT_SYMBOL_GPL(nfs_access_zap_cache);
2659
2660static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred)
2661{
2662 struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
2663
2664 while (n != NULL) {
2665 struct nfs_access_entry *entry =
2666 rb_entry(n, struct nfs_access_entry, rb_node);
2667 int cmp = cred_fscmp(cred, entry->cred);
2668
2669 if (cmp < 0)
2670 n = n->rb_left;
2671 else if (cmp > 0)
2672 n = n->rb_right;
2673 else
2674 return entry;
2675 }
2676 return NULL;
2677}
2678
2679static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res, bool may_block)
2680{
2681 struct nfs_inode *nfsi = NFS_I(inode);
2682 struct nfs_access_entry *cache;
2683 bool retry = true;
2684 int err;
2685
2686 spin_lock(&inode->i_lock);
2687 for(;;) {
2688 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2689 goto out_zap;
2690 cache = nfs_access_search_rbtree(inode, cred);
2691 err = -ENOENT;
2692 if (cache == NULL)
2693 goto out;
2694 /* Found an entry, is our attribute cache valid? */
2695 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2696 break;
2697 if (!retry)
2698 break;
2699 err = -ECHILD;
2700 if (!may_block)
2701 goto out;
2702 spin_unlock(&inode->i_lock);
2703 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
2704 if (err)
2705 return err;
2706 spin_lock(&inode->i_lock);
2707 retry = false;
2708 }
2709 res->cred = cache->cred;
2710 res->mask = cache->mask;
2711 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
2712 err = 0;
2713out:
2714 spin_unlock(&inode->i_lock);
2715 return err;
2716out_zap:
2717 spin_unlock(&inode->i_lock);
2718 nfs_access_zap_cache(inode);
2719 return -ENOENT;
2720}
2721
2722static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res)
2723{
2724 /* Only check the most recently returned cache entry,
2725 * but do it without locking.
2726 */
2727 struct nfs_inode *nfsi = NFS_I(inode);
2728 struct nfs_access_entry *cache;
2729 int err = -ECHILD;
2730 struct list_head *lh;
2731
2732 rcu_read_lock();
2733 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2734 goto out;
2735 lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru));
2736 cache = list_entry(lh, struct nfs_access_entry, lru);
2737 if (lh == &nfsi->access_cache_entry_lru ||
2738 cred_fscmp(cred, cache->cred) != 0)
2739 cache = NULL;
2740 if (cache == NULL)
2741 goto out;
2742 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2743 goto out;
2744 res->cred = cache->cred;
2745 res->mask = cache->mask;
2746 err = 0;
2747out:
2748 rcu_read_unlock();
2749 return err;
2750}
2751
2752int nfs_access_get_cached(struct inode *inode, const struct cred *cred, struct
2753nfs_access_entry *res, bool may_block)
2754{
2755 int status;
2756
2757 status = nfs_access_get_cached_rcu(inode, cred, res);
2758 if (status != 0)
2759 status = nfs_access_get_cached_locked(inode, cred, res,
2760 may_block);
2761
2762 return status;
2763}
2764EXPORT_SYMBOL_GPL(nfs_access_get_cached);
2765
2766static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
2767{
2768 struct nfs_inode *nfsi = NFS_I(inode);
2769 struct rb_root *root_node = &nfsi->access_cache;
2770 struct rb_node **p = &root_node->rb_node;
2771 struct rb_node *parent = NULL;
2772 struct nfs_access_entry *entry;
2773 int cmp;
2774
2775 spin_lock(&inode->i_lock);
2776 while (*p != NULL) {
2777 parent = *p;
2778 entry = rb_entry(parent, struct nfs_access_entry, rb_node);
2779 cmp = cred_fscmp(set->cred, entry->cred);
2780
2781 if (cmp < 0)
2782 p = &parent->rb_left;
2783 else if (cmp > 0)
2784 p = &parent->rb_right;
2785 else
2786 goto found;
2787 }
2788 rb_link_node(&set->rb_node, parent, p);
2789 rb_insert_color(&set->rb_node, root_node);
2790 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
2791 spin_unlock(&inode->i_lock);
2792 return;
2793found:
2794 rb_replace_node(parent, &set->rb_node, root_node);
2795 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
2796 list_del(&entry->lru);
2797 spin_unlock(&inode->i_lock);
2798 nfs_access_free_entry(entry);
2799}
2800
2801void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
2802{
2803 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
2804 if (cache == NULL)
2805 return;
2806 RB_CLEAR_NODE(&cache->rb_node);
2807 cache->cred = get_cred(set->cred);
2808 cache->mask = set->mask;
2809
2810 /* The above field assignments must be visible
2811 * before this item appears on the lru. We cannot easily
2812 * use rcu_assign_pointer, so just force the memory barrier.
2813 */
2814 smp_wmb();
2815 nfs_access_add_rbtree(inode, cache);
2816
2817 /* Update accounting */
2818 smp_mb__before_atomic();
2819 atomic_long_inc(&nfs_access_nr_entries);
2820 smp_mb__after_atomic();
2821
2822 /* Add inode to global LRU list */
2823 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) {
2824 spin_lock(&nfs_access_lru_lock);
2825 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
2826 list_add_tail(&NFS_I(inode)->access_cache_inode_lru,
2827 &nfs_access_lru_list);
2828 spin_unlock(&nfs_access_lru_lock);
2829 }
2830 nfs_access_cache_enforce_limit();
2831}
2832EXPORT_SYMBOL_GPL(nfs_access_add_cache);
2833
2834#define NFS_MAY_READ (NFS_ACCESS_READ)
2835#define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \
2836 NFS_ACCESS_EXTEND | \
2837 NFS_ACCESS_DELETE)
2838#define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \
2839 NFS_ACCESS_EXTEND)
2840#define NFS_DIR_MAY_WRITE NFS_MAY_WRITE
2841#define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP)
2842#define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE)
2843static int
2844nfs_access_calc_mask(u32 access_result, umode_t umode)
2845{
2846 int mask = 0;
2847
2848 if (access_result & NFS_MAY_READ)
2849 mask |= MAY_READ;
2850 if (S_ISDIR(umode)) {
2851 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE)
2852 mask |= MAY_WRITE;
2853 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP)
2854 mask |= MAY_EXEC;
2855 } else if (S_ISREG(umode)) {
2856 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE)
2857 mask |= MAY_WRITE;
2858 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE)
2859 mask |= MAY_EXEC;
2860 } else if (access_result & NFS_MAY_WRITE)
2861 mask |= MAY_WRITE;
2862 return mask;
2863}
2864
2865void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result)
2866{
2867 entry->mask = access_result;
2868}
2869EXPORT_SYMBOL_GPL(nfs_access_set_mask);
2870
2871static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask)
2872{
2873 struct nfs_access_entry cache;
2874 bool may_block = (mask & MAY_NOT_BLOCK) == 0;
2875 int cache_mask = -1;
2876 int status;
2877
2878 trace_nfs_access_enter(inode);
2879
2880 status = nfs_access_get_cached(inode, cred, &cache, may_block);
2881 if (status == 0)
2882 goto out_cached;
2883
2884 status = -ECHILD;
2885 if (!may_block)
2886 goto out;
2887
2888 /*
2889 * Determine which access bits we want to ask for...
2890 */
2891 cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND;
2892 if (nfs_server_capable(inode, NFS_CAP_XATTR)) {
2893 cache.mask |= NFS_ACCESS_XAREAD | NFS_ACCESS_XAWRITE |
2894 NFS_ACCESS_XALIST;
2895 }
2896 if (S_ISDIR(inode->i_mode))
2897 cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
2898 else
2899 cache.mask |= NFS_ACCESS_EXECUTE;
2900 cache.cred = cred;
2901 status = NFS_PROTO(inode)->access(inode, &cache);
2902 if (status != 0) {
2903 if (status == -ESTALE) {
2904 if (!S_ISDIR(inode->i_mode))
2905 nfs_set_inode_stale(inode);
2906 else
2907 nfs_zap_caches(inode);
2908 }
2909 goto out;
2910 }
2911 nfs_access_add_cache(inode, &cache);
2912out_cached:
2913 cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode);
2914 if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
2915 status = -EACCES;
2916out:
2917 trace_nfs_access_exit(inode, mask, cache_mask, status);
2918 return status;
2919}
2920
2921static int nfs_open_permission_mask(int openflags)
2922{
2923 int mask = 0;
2924
2925 if (openflags & __FMODE_EXEC) {
2926 /* ONLY check exec rights */
2927 mask = MAY_EXEC;
2928 } else {
2929 if ((openflags & O_ACCMODE) != O_WRONLY)
2930 mask |= MAY_READ;
2931 if ((openflags & O_ACCMODE) != O_RDONLY)
2932 mask |= MAY_WRITE;
2933 }
2934
2935 return mask;
2936}
2937
2938int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags)
2939{
2940 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags));
2941}
2942EXPORT_SYMBOL_GPL(nfs_may_open);
2943
2944static int nfs_execute_ok(struct inode *inode, int mask)
2945{
2946 struct nfs_server *server = NFS_SERVER(inode);
2947 int ret = 0;
2948
2949 if (S_ISDIR(inode->i_mode))
2950 return 0;
2951 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_MODE)) {
2952 if (mask & MAY_NOT_BLOCK)
2953 return -ECHILD;
2954 ret = __nfs_revalidate_inode(server, inode);
2955 }
2956 if (ret == 0 && !execute_ok(inode))
2957 ret = -EACCES;
2958 return ret;
2959}
2960
2961int nfs_permission(struct user_namespace *mnt_userns,
2962 struct inode *inode,
2963 int mask)
2964{
2965 const struct cred *cred = current_cred();
2966 int res = 0;
2967
2968 nfs_inc_stats(inode, NFSIOS_VFSACCESS);
2969
2970 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
2971 goto out;
2972 /* Is this sys_access() ? */
2973 if (mask & (MAY_ACCESS | MAY_CHDIR))
2974 goto force_lookup;
2975
2976 switch (inode->i_mode & S_IFMT) {
2977 case S_IFLNK:
2978 goto out;
2979 case S_IFREG:
2980 if ((mask & MAY_OPEN) &&
2981 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN))
2982 return 0;
2983 break;
2984 case S_IFDIR:
2985 /*
2986 * Optimize away all write operations, since the server
2987 * will check permissions when we perform the op.
2988 */
2989 if ((mask & MAY_WRITE) && !(mask & MAY_READ))
2990 goto out;
2991 }
2992
2993force_lookup:
2994 if (!NFS_PROTO(inode)->access)
2995 goto out_notsup;
2996
2997 res = nfs_do_access(inode, cred, mask);
2998out:
2999 if (!res && (mask & MAY_EXEC))
3000 res = nfs_execute_ok(inode, mask);
3001
3002 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n",
3003 inode->i_sb->s_id, inode->i_ino, mask, res);
3004 return res;
3005out_notsup:
3006 if (mask & MAY_NOT_BLOCK)
3007 return -ECHILD;
3008
3009 res = nfs_revalidate_inode(inode, NFS_INO_INVALID_MODE |
3010 NFS_INO_INVALID_OTHER);
3011 if (res == 0)
3012 res = generic_permission(&init_user_ns, inode, mask);
3013 goto out;
3014}
3015EXPORT_SYMBOL_GPL(nfs_permission);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/dir.c
4 *
5 * Copyright (C) 1992 Rick Sladkey
6 *
7 * nfs directory handling functions
8 *
9 * 10 Apr 1996 Added silly rename for unlink --okir
10 * 28 Sep 1996 Improved directory cache --okir
11 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de
12 * Re-implemented silly rename for unlink, newly implemented
13 * silly rename for nfs_rename() following the suggestions
14 * of Olaf Kirch (okir) found in this file.
15 * Following Linus comments on my original hack, this version
16 * depends only on the dcache stuff and doesn't touch the inode
17 * layer (iput() and friends).
18 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM
19 */
20
21#include <linux/module.h>
22#include <linux/time.h>
23#include <linux/errno.h>
24#include <linux/stat.h>
25#include <linux/fcntl.h>
26#include <linux/string.h>
27#include <linux/kernel.h>
28#include <linux/slab.h>
29#include <linux/mm.h>
30#include <linux/sunrpc/clnt.h>
31#include <linux/nfs_fs.h>
32#include <linux/nfs_mount.h>
33#include <linux/pagemap.h>
34#include <linux/pagevec.h>
35#include <linux/namei.h>
36#include <linux/mount.h>
37#include <linux/swap.h>
38#include <linux/sched.h>
39#include <linux/kmemleak.h>
40#include <linux/xattr.h>
41
42#include "delegation.h"
43#include "iostat.h"
44#include "internal.h"
45#include "fscache.h"
46
47#include "nfstrace.h"
48
49/* #define NFS_DEBUG_VERBOSE 1 */
50
51static int nfs_opendir(struct inode *, struct file *);
52static int nfs_closedir(struct inode *, struct file *);
53static int nfs_readdir(struct file *, struct dir_context *);
54static int nfs_fsync_dir(struct file *, loff_t, loff_t, int);
55static loff_t nfs_llseek_dir(struct file *, loff_t, int);
56static void nfs_readdir_clear_array(struct page*);
57
58const struct file_operations nfs_dir_operations = {
59 .llseek = nfs_llseek_dir,
60 .read = generic_read_dir,
61 .iterate_shared = nfs_readdir,
62 .open = nfs_opendir,
63 .release = nfs_closedir,
64 .fsync = nfs_fsync_dir,
65};
66
67const struct address_space_operations nfs_dir_aops = {
68 .freepage = nfs_readdir_clear_array,
69};
70
71static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, const struct cred *cred)
72{
73 struct nfs_inode *nfsi = NFS_I(dir);
74 struct nfs_open_dir_context *ctx;
75 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
76 if (ctx != NULL) {
77 ctx->duped = 0;
78 ctx->attr_gencount = nfsi->attr_gencount;
79 ctx->dir_cookie = 0;
80 ctx->dup_cookie = 0;
81 ctx->cred = get_cred(cred);
82 spin_lock(&dir->i_lock);
83 if (list_empty(&nfsi->open_files) &&
84 (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
85 nfsi->cache_validity |= NFS_INO_INVALID_DATA |
86 NFS_INO_REVAL_FORCED;
87 list_add(&ctx->list, &nfsi->open_files);
88 spin_unlock(&dir->i_lock);
89 return ctx;
90 }
91 return ERR_PTR(-ENOMEM);
92}
93
94static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
95{
96 spin_lock(&dir->i_lock);
97 list_del(&ctx->list);
98 spin_unlock(&dir->i_lock);
99 put_cred(ctx->cred);
100 kfree(ctx);
101}
102
103/*
104 * Open file
105 */
106static int
107nfs_opendir(struct inode *inode, struct file *filp)
108{
109 int res = 0;
110 struct nfs_open_dir_context *ctx;
111
112 dfprintk(FILE, "NFS: open dir(%pD2)\n", filp);
113
114 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
115
116 ctx = alloc_nfs_open_dir_context(inode, current_cred());
117 if (IS_ERR(ctx)) {
118 res = PTR_ERR(ctx);
119 goto out;
120 }
121 filp->private_data = ctx;
122out:
123 return res;
124}
125
126static int
127nfs_closedir(struct inode *inode, struct file *filp)
128{
129 put_nfs_open_dir_context(file_inode(filp), filp->private_data);
130 return 0;
131}
132
133struct nfs_cache_array_entry {
134 u64 cookie;
135 u64 ino;
136 struct qstr string;
137 unsigned char d_type;
138};
139
140struct nfs_cache_array {
141 int size;
142 int eof_index;
143 u64 last_cookie;
144 struct nfs_cache_array_entry array[];
145};
146
147typedef struct {
148 struct file *file;
149 struct page *page;
150 struct dir_context *ctx;
151 unsigned long page_index;
152 u64 *dir_cookie;
153 u64 last_cookie;
154 loff_t current_index;
155 loff_t prev_index;
156
157 unsigned long dir_verifier;
158 unsigned long timestamp;
159 unsigned long gencount;
160 unsigned int cache_entry_index;
161 bool plus;
162 bool eof;
163} nfs_readdir_descriptor_t;
164
165static
166void nfs_readdir_init_array(struct page *page)
167{
168 struct nfs_cache_array *array;
169
170 array = kmap_atomic(page);
171 memset(array, 0, sizeof(struct nfs_cache_array));
172 array->eof_index = -1;
173 kunmap_atomic(array);
174}
175
176/*
177 * we are freeing strings created by nfs_add_to_readdir_array()
178 */
179static
180void nfs_readdir_clear_array(struct page *page)
181{
182 struct nfs_cache_array *array;
183 int i;
184
185 array = kmap_atomic(page);
186 for (i = 0; i < array->size; i++)
187 kfree(array->array[i].string.name);
188 array->size = 0;
189 kunmap_atomic(array);
190}
191
192/*
193 * the caller is responsible for freeing qstr.name
194 * when called by nfs_readdir_add_to_array, the strings will be freed in
195 * nfs_clear_readdir_array()
196 */
197static
198int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len)
199{
200 string->len = len;
201 string->name = kmemdup_nul(name, len, GFP_KERNEL);
202 if (string->name == NULL)
203 return -ENOMEM;
204 /*
205 * Avoid a kmemleak false positive. The pointer to the name is stored
206 * in a page cache page which kmemleak does not scan.
207 */
208 kmemleak_not_leak(string->name);
209 string->hash = full_name_hash(NULL, name, len);
210 return 0;
211}
212
213static
214int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
215{
216 struct nfs_cache_array *array = kmap(page);
217 struct nfs_cache_array_entry *cache_entry;
218 int ret;
219
220 cache_entry = &array->array[array->size];
221
222 /* Check that this entry lies within the page bounds */
223 ret = -ENOSPC;
224 if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE)
225 goto out;
226
227 cache_entry->cookie = entry->prev_cookie;
228 cache_entry->ino = entry->ino;
229 cache_entry->d_type = entry->d_type;
230 ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len);
231 if (ret)
232 goto out;
233 array->last_cookie = entry->cookie;
234 array->size++;
235 if (entry->eof != 0)
236 array->eof_index = array->size;
237out:
238 kunmap(page);
239 return ret;
240}
241
242static inline
243int is_32bit_api(void)
244{
245#ifdef CONFIG_COMPAT
246 return in_compat_syscall();
247#else
248 return (BITS_PER_LONG == 32);
249#endif
250}
251
252static
253bool nfs_readdir_use_cookie(const struct file *filp)
254{
255 if ((filp->f_mode & FMODE_32BITHASH) ||
256 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
257 return false;
258 return true;
259}
260
261static
262int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
263{
264 loff_t diff = desc->ctx->pos - desc->current_index;
265 unsigned int index;
266
267 if (diff < 0)
268 goto out_eof;
269 if (diff >= array->size) {
270 if (array->eof_index >= 0)
271 goto out_eof;
272 return -EAGAIN;
273 }
274
275 index = (unsigned int)diff;
276 *desc->dir_cookie = array->array[index].cookie;
277 desc->cache_entry_index = index;
278 return 0;
279out_eof:
280 desc->eof = true;
281 return -EBADCOOKIE;
282}
283
284static bool
285nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
286{
287 if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))
288 return false;
289 smp_rmb();
290 return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
291}
292
293static
294int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
295{
296 int i;
297 loff_t new_pos;
298 int status = -EAGAIN;
299
300 for (i = 0; i < array->size; i++) {
301 if (array->array[i].cookie == *desc->dir_cookie) {
302 struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));
303 struct nfs_open_dir_context *ctx = desc->file->private_data;
304
305 new_pos = desc->current_index + i;
306 if (ctx->attr_gencount != nfsi->attr_gencount ||
307 !nfs_readdir_inode_mapping_valid(nfsi)) {
308 ctx->duped = 0;
309 ctx->attr_gencount = nfsi->attr_gencount;
310 } else if (new_pos < desc->prev_index) {
311 if (ctx->duped > 0
312 && ctx->dup_cookie == *desc->dir_cookie) {
313 if (printk_ratelimit()) {
314 pr_notice("NFS: directory %pD2 contains a readdir loop."
315 "Please contact your server vendor. "
316 "The file: %.*s has duplicate cookie %llu\n",
317 desc->file, array->array[i].string.len,
318 array->array[i].string.name, *desc->dir_cookie);
319 }
320 status = -ELOOP;
321 goto out;
322 }
323 ctx->dup_cookie = *desc->dir_cookie;
324 ctx->duped = -1;
325 }
326 if (nfs_readdir_use_cookie(desc->file))
327 desc->ctx->pos = *desc->dir_cookie;
328 else
329 desc->ctx->pos = new_pos;
330 desc->prev_index = new_pos;
331 desc->cache_entry_index = i;
332 return 0;
333 }
334 }
335 if (array->eof_index >= 0) {
336 status = -EBADCOOKIE;
337 if (*desc->dir_cookie == array->last_cookie)
338 desc->eof = true;
339 }
340out:
341 return status;
342}
343
344static
345int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
346{
347 struct nfs_cache_array *array;
348 int status;
349
350 array = kmap(desc->page);
351
352 if (*desc->dir_cookie == 0)
353 status = nfs_readdir_search_for_pos(array, desc);
354 else
355 status = nfs_readdir_search_for_cookie(array, desc);
356
357 if (status == -EAGAIN) {
358 desc->last_cookie = array->last_cookie;
359 desc->current_index += array->size;
360 desc->page_index++;
361 }
362 kunmap(desc->page);
363 return status;
364}
365
366/* Fill a page with xdr information before transferring to the cache page */
367static
368int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc,
369 struct nfs_entry *entry, struct file *file, struct inode *inode)
370{
371 struct nfs_open_dir_context *ctx = file->private_data;
372 const struct cred *cred = ctx->cred;
373 unsigned long timestamp, gencount;
374 int error;
375
376 again:
377 timestamp = jiffies;
378 gencount = nfs_inc_attr_generation_counter();
379 desc->dir_verifier = nfs_save_change_attribute(inode);
380 error = NFS_PROTO(inode)->readdir(file_dentry(file), cred, entry->cookie, pages,
381 NFS_SERVER(inode)->dtsize, desc->plus);
382 if (error < 0) {
383 /* We requested READDIRPLUS, but the server doesn't grok it */
384 if (error == -ENOTSUPP && desc->plus) {
385 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
386 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
387 desc->plus = false;
388 goto again;
389 }
390 goto error;
391 }
392 desc->timestamp = timestamp;
393 desc->gencount = gencount;
394error:
395 return error;
396}
397
398static int xdr_decode(nfs_readdir_descriptor_t *desc,
399 struct nfs_entry *entry, struct xdr_stream *xdr)
400{
401 struct inode *inode = file_inode(desc->file);
402 int error;
403
404 error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus);
405 if (error)
406 return error;
407 entry->fattr->time_start = desc->timestamp;
408 entry->fattr->gencount = desc->gencount;
409 return 0;
410}
411
412/* Match file and dirent using either filehandle or fileid
413 * Note: caller is responsible for checking the fsid
414 */
415static
416int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
417{
418 struct inode *inode;
419 struct nfs_inode *nfsi;
420
421 if (d_really_is_negative(dentry))
422 return 0;
423
424 inode = d_inode(dentry);
425 if (is_bad_inode(inode) || NFS_STALE(inode))
426 return 0;
427
428 nfsi = NFS_I(inode);
429 if (entry->fattr->fileid != nfsi->fileid)
430 return 0;
431 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0)
432 return 0;
433 return 1;
434}
435
436static
437bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx)
438{
439 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
440 return false;
441 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags))
442 return true;
443 if (ctx->pos == 0)
444 return true;
445 return false;
446}
447
448/*
449 * This function is called by the lookup and getattr code to request the
450 * use of readdirplus to accelerate any future lookups in the same
451 * directory.
452 */
453void nfs_advise_use_readdirplus(struct inode *dir)
454{
455 struct nfs_inode *nfsi = NFS_I(dir);
456
457 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
458 !list_empty(&nfsi->open_files))
459 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
460}
461
462/*
463 * This function is mainly for use by nfs_getattr().
464 *
465 * If this is an 'ls -l', we want to force use of readdirplus.
466 * Do this by checking if there is an active file descriptor
467 * and calling nfs_advise_use_readdirplus, then forcing a
468 * cache flush.
469 */
470void nfs_force_use_readdirplus(struct inode *dir)
471{
472 struct nfs_inode *nfsi = NFS_I(dir);
473
474 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
475 !list_empty(&nfsi->open_files)) {
476 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags);
477 invalidate_mapping_pages(dir->i_mapping,
478 nfsi->page_index + 1, -1);
479 }
480}
481
482static
483void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
484 unsigned long dir_verifier)
485{
486 struct qstr filename = QSTR_INIT(entry->name, entry->len);
487 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
488 struct dentry *dentry;
489 struct dentry *alias;
490 struct inode *inode;
491 int status;
492
493 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID))
494 return;
495 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID))
496 return;
497 if (filename.len == 0)
498 return;
499 /* Validate that the name doesn't contain any illegal '\0' */
500 if (strnlen(filename.name, filename.len) != filename.len)
501 return;
502 /* ...or '/' */
503 if (strnchr(filename.name, filename.len, '/'))
504 return;
505 if (filename.name[0] == '.') {
506 if (filename.len == 1)
507 return;
508 if (filename.len == 2 && filename.name[1] == '.')
509 return;
510 }
511 filename.hash = full_name_hash(parent, filename.name, filename.len);
512
513 dentry = d_lookup(parent, &filename);
514again:
515 if (!dentry) {
516 dentry = d_alloc_parallel(parent, &filename, &wq);
517 if (IS_ERR(dentry))
518 return;
519 }
520 if (!d_in_lookup(dentry)) {
521 /* Is there a mountpoint here? If so, just exit */
522 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid,
523 &entry->fattr->fsid))
524 goto out;
525 if (nfs_same_file(dentry, entry)) {
526 if (!entry->fh->size)
527 goto out;
528 nfs_set_verifier(dentry, dir_verifier);
529 status = nfs_refresh_inode(d_inode(dentry), entry->fattr);
530 if (!status)
531 nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label);
532 goto out;
533 } else {
534 d_invalidate(dentry);
535 dput(dentry);
536 dentry = NULL;
537 goto again;
538 }
539 }
540 if (!entry->fh->size) {
541 d_lookup_done(dentry);
542 goto out;
543 }
544
545 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label);
546 alias = d_splice_alias(inode, dentry);
547 d_lookup_done(dentry);
548 if (alias) {
549 if (IS_ERR(alias))
550 goto out;
551 dput(dentry);
552 dentry = alias;
553 }
554 nfs_set_verifier(dentry, dir_verifier);
555out:
556 dput(dentry);
557}
558
559/* Perform conversion from xdr to cache array */
560static
561int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
562 struct page **xdr_pages, struct page *page, unsigned int buflen)
563{
564 struct xdr_stream stream;
565 struct xdr_buf buf;
566 struct page *scratch;
567 struct nfs_cache_array *array;
568 unsigned int count = 0;
569 int status;
570
571 scratch = alloc_page(GFP_KERNEL);
572 if (scratch == NULL)
573 return -ENOMEM;
574
575 if (buflen == 0)
576 goto out_nopages;
577
578 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
579 xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
580
581 do {
582 if (entry->label)
583 entry->label->len = NFS4_MAXLABELLEN;
584
585 status = xdr_decode(desc, entry, &stream);
586 if (status != 0) {
587 if (status == -EAGAIN)
588 status = 0;
589 break;
590 }
591
592 count++;
593
594 if (desc->plus)
595 nfs_prime_dcache(file_dentry(desc->file), entry,
596 desc->dir_verifier);
597
598 status = nfs_readdir_add_to_array(entry, page);
599 if (status != 0)
600 break;
601 } while (!entry->eof);
602
603out_nopages:
604 if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
605 array = kmap(page);
606 array->eof_index = array->size;
607 status = 0;
608 kunmap(page);
609 }
610
611 put_page(scratch);
612 return status;
613}
614
615static
616void nfs_readdir_free_pages(struct page **pages, unsigned int npages)
617{
618 unsigned int i;
619 for (i = 0; i < npages; i++)
620 put_page(pages[i]);
621}
622
623/*
624 * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call
625 * to nfs_readdir_free_pages()
626 */
627static
628int nfs_readdir_alloc_pages(struct page **pages, unsigned int npages)
629{
630 unsigned int i;
631
632 for (i = 0; i < npages; i++) {
633 struct page *page = alloc_page(GFP_KERNEL);
634 if (page == NULL)
635 goto out_freepages;
636 pages[i] = page;
637 }
638 return 0;
639
640out_freepages:
641 nfs_readdir_free_pages(pages, i);
642 return -ENOMEM;
643}
644
645static
646int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
647{
648 struct page *pages[NFS_MAX_READDIR_PAGES];
649 struct nfs_entry entry;
650 struct file *file = desc->file;
651 struct nfs_cache_array *array;
652 int status = -ENOMEM;
653 unsigned int array_size = ARRAY_SIZE(pages);
654
655 nfs_readdir_init_array(page);
656
657 entry.prev_cookie = 0;
658 entry.cookie = desc->last_cookie;
659 entry.eof = 0;
660 entry.fh = nfs_alloc_fhandle();
661 entry.fattr = nfs_alloc_fattr();
662 entry.server = NFS_SERVER(inode);
663 if (entry.fh == NULL || entry.fattr == NULL)
664 goto out;
665
666 entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);
667 if (IS_ERR(entry.label)) {
668 status = PTR_ERR(entry.label);
669 goto out;
670 }
671
672 array = kmap(page);
673
674 status = nfs_readdir_alloc_pages(pages, array_size);
675 if (status < 0)
676 goto out_release_array;
677 do {
678 unsigned int pglen;
679 status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode);
680
681 if (status < 0)
682 break;
683 pglen = status;
684 status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
685 if (status < 0) {
686 if (status == -ENOSPC)
687 status = 0;
688 break;
689 }
690 } while (array->eof_index < 0);
691
692 nfs_readdir_free_pages(pages, array_size);
693out_release_array:
694 kunmap(page);
695 nfs4_label_free(entry.label);
696out:
697 nfs_free_fattr(entry.fattr);
698 nfs_free_fhandle(entry.fh);
699 return status;
700}
701
702/*
703 * Now we cache directories properly, by converting xdr information
704 * to an array that can be used for lookups later. This results in
705 * fewer cache pages, since we can store more information on each page.
706 * We only need to convert from xdr once so future lookups are much simpler
707 */
708static
709int nfs_readdir_filler(void *data, struct page* page)
710{
711 nfs_readdir_descriptor_t *desc = data;
712 struct inode *inode = file_inode(desc->file);
713 int ret;
714
715 ret = nfs_readdir_xdr_to_array(desc, page, inode);
716 if (ret < 0)
717 goto error;
718 SetPageUptodate(page);
719
720 if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) {
721 /* Should never happen */
722 nfs_zap_mapping(inode, inode->i_mapping);
723 }
724 unlock_page(page);
725 return 0;
726 error:
727 nfs_readdir_clear_array(page);
728 unlock_page(page);
729 return ret;
730}
731
732static
733void cache_page_release(nfs_readdir_descriptor_t *desc)
734{
735 put_page(desc->page);
736 desc->page = NULL;
737}
738
739static
740struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
741{
742 return read_cache_page(desc->file->f_mapping, desc->page_index,
743 nfs_readdir_filler, desc);
744}
745
746/*
747 * Returns 0 if desc->dir_cookie was found on page desc->page_index
748 * and locks the page to prevent removal from the page cache.
749 */
750static
751int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc)
752{
753 struct inode *inode = file_inode(desc->file);
754 struct nfs_inode *nfsi = NFS_I(inode);
755 int res;
756
757 desc->page = get_cache_page(desc);
758 if (IS_ERR(desc->page))
759 return PTR_ERR(desc->page);
760 res = lock_page_killable(desc->page);
761 if (res != 0)
762 goto error;
763 res = -EAGAIN;
764 if (desc->page->mapping != NULL) {
765 res = nfs_readdir_search_array(desc);
766 if (res == 0) {
767 nfsi->page_index = desc->page_index;
768 return 0;
769 }
770 }
771 unlock_page(desc->page);
772error:
773 cache_page_release(desc);
774 return res;
775}
776
777/* Search for desc->dir_cookie from the beginning of the page cache */
778static inline
779int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
780{
781 int res;
782
783 if (desc->page_index == 0) {
784 desc->current_index = 0;
785 desc->prev_index = 0;
786 desc->last_cookie = 0;
787 }
788 do {
789 res = find_and_lock_cache_page(desc);
790 } while (res == -EAGAIN);
791 return res;
792}
793
794/*
795 * Once we've found the start of the dirent within a page: fill 'er up...
796 */
797static
798int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
799{
800 struct file *file = desc->file;
801 int i = 0;
802 int res = 0;
803 struct nfs_cache_array *array = NULL;
804 struct nfs_open_dir_context *ctx = file->private_data;
805
806 array = kmap(desc->page);
807 for (i = desc->cache_entry_index; i < array->size; i++) {
808 struct nfs_cache_array_entry *ent;
809
810 ent = &array->array[i];
811 if (!dir_emit(desc->ctx, ent->string.name, ent->string.len,
812 nfs_compat_user_ino64(ent->ino), ent->d_type)) {
813 desc->eof = true;
814 break;
815 }
816 if (i < (array->size-1))
817 *desc->dir_cookie = array->array[i+1].cookie;
818 else
819 *desc->dir_cookie = array->last_cookie;
820 if (nfs_readdir_use_cookie(file))
821 desc->ctx->pos = *desc->dir_cookie;
822 else
823 desc->ctx->pos++;
824 if (ctx->duped != 0)
825 ctx->duped = 1;
826 }
827 if (array->eof_index >= 0)
828 desc->eof = true;
829
830 kunmap(desc->page);
831 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
832 (unsigned long long)*desc->dir_cookie, res);
833 return res;
834}
835
836/*
837 * If we cannot find a cookie in our cache, we suspect that this is
838 * because it points to a deleted file, so we ask the server to return
839 * whatever it thinks is the next entry. We then feed this to filldir.
840 * If all goes well, we should then be able to find our way round the
841 * cache on the next call to readdir_search_pagecache();
842 *
843 * NOTE: we cannot add the anonymous page to the pagecache because
844 * the data it contains might not be page aligned. Besides,
845 * we should already have a complete representation of the
846 * directory in the page cache by the time we get here.
847 */
848static inline
849int uncached_readdir(nfs_readdir_descriptor_t *desc)
850{
851 struct page *page = NULL;
852 int status;
853 struct inode *inode = file_inode(desc->file);
854 struct nfs_open_dir_context *ctx = desc->file->private_data;
855
856 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
857 (unsigned long long)*desc->dir_cookie);
858
859 page = alloc_page(GFP_HIGHUSER);
860 if (!page) {
861 status = -ENOMEM;
862 goto out;
863 }
864
865 desc->page_index = 0;
866 desc->last_cookie = *desc->dir_cookie;
867 desc->page = page;
868 ctx->duped = 0;
869
870 status = nfs_readdir_xdr_to_array(desc, page, inode);
871 if (status < 0)
872 goto out_release;
873
874 status = nfs_do_filldir(desc);
875
876 out_release:
877 nfs_readdir_clear_array(desc->page);
878 cache_page_release(desc);
879 out:
880 dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
881 __func__, status);
882 return status;
883}
884
885/* The file offset position represents the dirent entry number. A
886 last cookie cache takes care of the common case of reading the
887 whole directory.
888 */
889static int nfs_readdir(struct file *file, struct dir_context *ctx)
890{
891 struct dentry *dentry = file_dentry(file);
892 struct inode *inode = d_inode(dentry);
893 struct nfs_open_dir_context *dir_ctx = file->private_data;
894 nfs_readdir_descriptor_t my_desc = {
895 .file = file,
896 .ctx = ctx,
897 .dir_cookie = &dir_ctx->dir_cookie,
898 .plus = nfs_use_readdirplus(inode, ctx),
899 },
900 *desc = &my_desc;
901 int res = 0;
902
903 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
904 file, (long long)ctx->pos);
905 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
906
907 /*
908 * ctx->pos points to the dirent entry number.
909 * *desc->dir_cookie has the cookie for the next entry. We have
910 * to either find the entry with the appropriate number or
911 * revalidate the cookie.
912 */
913 if (ctx->pos == 0 || nfs_attribute_cache_expired(inode))
914 res = nfs_revalidate_mapping(inode, file->f_mapping);
915 if (res < 0)
916 goto out;
917
918 do {
919 res = readdir_search_pagecache(desc);
920
921 if (res == -EBADCOOKIE) {
922 res = 0;
923 /* This means either end of directory */
924 if (*desc->dir_cookie && !desc->eof) {
925 /* Or that the server has 'lost' a cookie */
926 res = uncached_readdir(desc);
927 if (res == 0)
928 continue;
929 }
930 break;
931 }
932 if (res == -ETOOSMALL && desc->plus) {
933 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
934 nfs_zap_caches(inode);
935 desc->page_index = 0;
936 desc->plus = false;
937 desc->eof = false;
938 continue;
939 }
940 if (res < 0)
941 break;
942
943 res = nfs_do_filldir(desc);
944 unlock_page(desc->page);
945 cache_page_release(desc);
946 if (res < 0)
947 break;
948 } while (!desc->eof);
949out:
950 if (res > 0)
951 res = 0;
952 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res);
953 return res;
954}
955
956static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
957{
958 struct inode *inode = file_inode(filp);
959 struct nfs_open_dir_context *dir_ctx = filp->private_data;
960
961 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",
962 filp, offset, whence);
963
964 switch (whence) {
965 default:
966 return -EINVAL;
967 case SEEK_SET:
968 if (offset < 0)
969 return -EINVAL;
970 inode_lock(inode);
971 break;
972 case SEEK_CUR:
973 if (offset == 0)
974 return filp->f_pos;
975 inode_lock(inode);
976 offset += filp->f_pos;
977 if (offset < 0) {
978 inode_unlock(inode);
979 return -EINVAL;
980 }
981 }
982 if (offset != filp->f_pos) {
983 filp->f_pos = offset;
984 if (nfs_readdir_use_cookie(filp))
985 dir_ctx->dir_cookie = offset;
986 else
987 dir_ctx->dir_cookie = 0;
988 dir_ctx->duped = 0;
989 }
990 inode_unlock(inode);
991 return offset;
992}
993
994/*
995 * All directory operations under NFS are synchronous, so fsync()
996 * is a dummy operation.
997 */
998static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end,
999 int datasync)
1000{
1001 struct inode *inode = file_inode(filp);
1002
1003 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync);
1004
1005 inode_lock(inode);
1006 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
1007 inode_unlock(inode);
1008 return 0;
1009}
1010
1011/**
1012 * nfs_force_lookup_revalidate - Mark the directory as having changed
1013 * @dir: pointer to directory inode
1014 *
1015 * This forces the revalidation code in nfs_lookup_revalidate() to do a
1016 * full lookup on all child dentries of 'dir' whenever a change occurs
1017 * on the server that might have invalidated our dcache.
1018 *
1019 * Note that we reserve bit '0' as a tag to let us know when a dentry
1020 * was revalidated while holding a delegation on its inode.
1021 *
1022 * The caller should be holding dir->i_lock
1023 */
1024void nfs_force_lookup_revalidate(struct inode *dir)
1025{
1026 NFS_I(dir)->cache_change_attribute += 2;
1027}
1028EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
1029
1030/**
1031 * nfs_verify_change_attribute - Detects NFS remote directory changes
1032 * @dir: pointer to parent directory inode
1033 * @verf: previously saved change attribute
1034 *
1035 * Return "false" if the verifiers doesn't match the change attribute.
1036 * This would usually indicate that the directory contents have changed on
1037 * the server, and that any dentries need revalidating.
1038 */
1039static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf)
1040{
1041 return (verf & ~1UL) == nfs_save_change_attribute(dir);
1042}
1043
1044static void nfs_set_verifier_delegated(unsigned long *verf)
1045{
1046 *verf |= 1UL;
1047}
1048
1049#if IS_ENABLED(CONFIG_NFS_V4)
1050static void nfs_unset_verifier_delegated(unsigned long *verf)
1051{
1052 *verf &= ~1UL;
1053}
1054#endif /* IS_ENABLED(CONFIG_NFS_V4) */
1055
1056static bool nfs_test_verifier_delegated(unsigned long verf)
1057{
1058 return verf & 1;
1059}
1060
1061static bool nfs_verifier_is_delegated(struct dentry *dentry)
1062{
1063 return nfs_test_verifier_delegated(dentry->d_time);
1064}
1065
1066static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf)
1067{
1068 struct inode *inode = d_inode(dentry);
1069
1070 if (!nfs_verifier_is_delegated(dentry) &&
1071 !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf))
1072 goto out;
1073 if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
1074 nfs_set_verifier_delegated(&verf);
1075out:
1076 dentry->d_time = verf;
1077}
1078
1079/**
1080 * nfs_set_verifier - save a parent directory verifier in the dentry
1081 * @dentry: pointer to dentry
1082 * @verf: verifier to save
1083 *
1084 * Saves the parent directory verifier in @dentry. If the inode has
1085 * a delegation, we also tag the dentry as having been revalidated
1086 * while holding a delegation so that we know we don't have to
1087 * look it up again after a directory change.
1088 */
1089void nfs_set_verifier(struct dentry *dentry, unsigned long verf)
1090{
1091
1092 spin_lock(&dentry->d_lock);
1093 nfs_set_verifier_locked(dentry, verf);
1094 spin_unlock(&dentry->d_lock);
1095}
1096EXPORT_SYMBOL_GPL(nfs_set_verifier);
1097
1098#if IS_ENABLED(CONFIG_NFS_V4)
1099/**
1100 * nfs_clear_verifier_delegated - clear the dir verifier delegation tag
1101 * @inode: pointer to inode
1102 *
1103 * Iterates through the dentries in the inode alias list and clears
1104 * the tag used to indicate that the dentry has been revalidated
1105 * while holding a delegation.
1106 * This function is intended for use when the delegation is being
1107 * returned or revoked.
1108 */
1109void nfs_clear_verifier_delegated(struct inode *inode)
1110{
1111 struct dentry *alias;
1112
1113 if (!inode)
1114 return;
1115 spin_lock(&inode->i_lock);
1116 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
1117 spin_lock(&alias->d_lock);
1118 nfs_unset_verifier_delegated(&alias->d_time);
1119 spin_unlock(&alias->d_lock);
1120 }
1121 spin_unlock(&inode->i_lock);
1122}
1123EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated);
1124#endif /* IS_ENABLED(CONFIG_NFS_V4) */
1125
1126/*
1127 * A check for whether or not the parent directory has changed.
1128 * In the case it has, we assume that the dentries are untrustworthy
1129 * and may need to be looked up again.
1130 * If rcu_walk prevents us from performing a full check, return 0.
1131 */
1132static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
1133 int rcu_walk)
1134{
1135 if (IS_ROOT(dentry))
1136 return 1;
1137 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
1138 return 0;
1139 if (!nfs_verify_change_attribute(dir, dentry->d_time))
1140 return 0;
1141 /* Revalidate nfsi->cache_change_attribute before we declare a match */
1142 if (nfs_mapping_need_revalidate_inode(dir)) {
1143 if (rcu_walk)
1144 return 0;
1145 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
1146 return 0;
1147 }
1148 if (!nfs_verify_change_attribute(dir, dentry->d_time))
1149 return 0;
1150 return 1;
1151}
1152
1153/*
1154 * Use intent information to check whether or not we're going to do
1155 * an O_EXCL create using this path component.
1156 */
1157static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags)
1158{
1159 if (NFS_PROTO(dir)->version == 2)
1160 return 0;
1161 return flags & LOOKUP_EXCL;
1162}
1163
1164/*
1165 * Inode and filehandle revalidation for lookups.
1166 *
1167 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
1168 * or if the intent information indicates that we're about to open this
1169 * particular file and the "nocto" mount flag is not set.
1170 *
1171 */
1172static
1173int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
1174{
1175 struct nfs_server *server = NFS_SERVER(inode);
1176 int ret;
1177
1178 if (IS_AUTOMOUNT(inode))
1179 return 0;
1180
1181 if (flags & LOOKUP_OPEN) {
1182 switch (inode->i_mode & S_IFMT) {
1183 case S_IFREG:
1184 /* A NFSv4 OPEN will revalidate later */
1185 if (server->caps & NFS_CAP_ATOMIC_OPEN)
1186 goto out;
1187 fallthrough;
1188 case S_IFDIR:
1189 if (server->flags & NFS_MOUNT_NOCTO)
1190 break;
1191 /* NFS close-to-open cache consistency validation */
1192 goto out_force;
1193 }
1194 }
1195
1196 /* VFS wants an on-the-wire revalidation */
1197 if (flags & LOOKUP_REVAL)
1198 goto out_force;
1199out:
1200 return (inode->i_nlink == 0) ? -ESTALE : 0;
1201out_force:
1202 if (flags & LOOKUP_RCU)
1203 return -ECHILD;
1204 ret = __nfs_revalidate_inode(server, inode);
1205 if (ret != 0)
1206 return ret;
1207 goto out;
1208}
1209
1210/*
1211 * We judge how long we want to trust negative
1212 * dentries by looking at the parent inode mtime.
1213 *
1214 * If parent mtime has changed, we revalidate, else we wait for a
1215 * period corresponding to the parent's attribute cache timeout value.
1216 *
1217 * If LOOKUP_RCU prevents us from performing a full check, return 1
1218 * suggesting a reval is needed.
1219 *
1220 * Note that when creating a new file, or looking up a rename target,
1221 * then it shouldn't be necessary to revalidate a negative dentry.
1222 */
1223static inline
1224int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
1225 unsigned int flags)
1226{
1227 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
1228 return 0;
1229 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)
1230 return 1;
1231 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU);
1232}
1233
1234static int
1235nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
1236 struct inode *inode, int error)
1237{
1238 switch (error) {
1239 case 1:
1240 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
1241 __func__, dentry);
1242 return 1;
1243 case 0:
1244 nfs_mark_for_revalidate(dir);
1245 if (inode && S_ISDIR(inode->i_mode)) {
1246 /* Purge readdir caches. */
1247 nfs_zap_caches(inode);
1248 /*
1249 * We can't d_drop the root of a disconnected tree:
1250 * its d_hash is on the s_anon list and d_drop() would hide
1251 * it from shrink_dcache_for_unmount(), leading to busy
1252 * inodes on unmount and further oopses.
1253 */
1254 if (IS_ROOT(dentry))
1255 return 1;
1256 }
1257 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
1258 __func__, dentry);
1259 return 0;
1260 }
1261 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
1262 __func__, dentry, error);
1263 return error;
1264}
1265
1266static int
1267nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry,
1268 unsigned int flags)
1269{
1270 int ret = 1;
1271 if (nfs_neg_need_reval(dir, dentry, flags)) {
1272 if (flags & LOOKUP_RCU)
1273 return -ECHILD;
1274 ret = 0;
1275 }
1276 return nfs_lookup_revalidate_done(dir, dentry, NULL, ret);
1277}
1278
1279static int
1280nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
1281 struct inode *inode)
1282{
1283 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1284 return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1285}
1286
1287static int
1288nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
1289 struct inode *inode)
1290{
1291 struct nfs_fh *fhandle;
1292 struct nfs_fattr *fattr;
1293 struct nfs4_label *label;
1294 unsigned long dir_verifier;
1295 int ret;
1296
1297 ret = -ENOMEM;
1298 fhandle = nfs_alloc_fhandle();
1299 fattr = nfs_alloc_fattr();
1300 label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL);
1301 if (fhandle == NULL || fattr == NULL || IS_ERR(label))
1302 goto out;
1303
1304 dir_verifier = nfs_save_change_attribute(dir);
1305 ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
1306 if (ret < 0) {
1307 switch (ret) {
1308 case -ESTALE:
1309 case -ENOENT:
1310 ret = 0;
1311 break;
1312 case -ETIMEDOUT:
1313 if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
1314 ret = 1;
1315 }
1316 goto out;
1317 }
1318 ret = 0;
1319 if (nfs_compare_fh(NFS_FH(inode), fhandle))
1320 goto out;
1321 if (nfs_refresh_inode(inode, fattr) < 0)
1322 goto out;
1323
1324 nfs_setsecurity(inode, fattr, label);
1325 nfs_set_verifier(dentry, dir_verifier);
1326
1327 /* set a readdirplus hint that we had a cache miss */
1328 nfs_force_use_readdirplus(dir);
1329 ret = 1;
1330out:
1331 nfs_free_fattr(fattr);
1332 nfs_free_fhandle(fhandle);
1333 nfs4_label_free(label);
1334 return nfs_lookup_revalidate_done(dir, dentry, inode, ret);
1335}
1336
1337/*
1338 * This is called every time the dcache has a lookup hit,
1339 * and we should check whether we can really trust that
1340 * lookup.
1341 *
1342 * NOTE! The hit can be a negative hit too, don't assume
1343 * we have an inode!
1344 *
1345 * If the parent directory is seen to have changed, we throw out the
1346 * cached dentry and do a new lookup.
1347 */
1348static int
1349nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
1350 unsigned int flags)
1351{
1352 struct inode *inode;
1353 int error;
1354
1355 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
1356 inode = d_inode(dentry);
1357
1358 if (!inode)
1359 return nfs_lookup_revalidate_negative(dir, dentry, flags);
1360
1361 if (is_bad_inode(inode)) {
1362 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1363 __func__, dentry);
1364 goto out_bad;
1365 }
1366
1367 if (nfs_verifier_is_delegated(dentry))
1368 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
1369
1370 /* Force a full look up iff the parent directory has changed */
1371 if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
1372 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
1373 error = nfs_lookup_verify_inode(inode, flags);
1374 if (error) {
1375 if (error == -ESTALE)
1376 nfs_zap_caches(dir);
1377 goto out_bad;
1378 }
1379 nfs_advise_use_readdirplus(dir);
1380 goto out_valid;
1381 }
1382
1383 if (flags & LOOKUP_RCU)
1384 return -ECHILD;
1385
1386 if (NFS_STALE(inode))
1387 goto out_bad;
1388
1389 trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
1390 error = nfs_lookup_revalidate_dentry(dir, dentry, inode);
1391 trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
1392 return error;
1393out_valid:
1394 return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1395out_bad:
1396 if (flags & LOOKUP_RCU)
1397 return -ECHILD;
1398 return nfs_lookup_revalidate_done(dir, dentry, inode, 0);
1399}
1400
1401static int
1402__nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags,
1403 int (*reval)(struct inode *, struct dentry *, unsigned int))
1404{
1405 struct dentry *parent;
1406 struct inode *dir;
1407 int ret;
1408
1409 if (flags & LOOKUP_RCU) {
1410 parent = READ_ONCE(dentry->d_parent);
1411 dir = d_inode_rcu(parent);
1412 if (!dir)
1413 return -ECHILD;
1414 ret = reval(dir, dentry, flags);
1415 if (parent != READ_ONCE(dentry->d_parent))
1416 return -ECHILD;
1417 } else {
1418 parent = dget_parent(dentry);
1419 ret = reval(d_inode(parent), dentry, flags);
1420 dput(parent);
1421 }
1422 return ret;
1423}
1424
1425static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
1426{
1427 return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate);
1428}
1429
1430/*
1431 * A weaker form of d_revalidate for revalidating just the d_inode(dentry)
1432 * when we don't really care about the dentry name. This is called when a
1433 * pathwalk ends on a dentry that was not found via a normal lookup in the
1434 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals).
1435 *
1436 * In this situation, we just want to verify that the inode itself is OK
1437 * since the dentry might have changed on the server.
1438 */
1439static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags)
1440{
1441 struct inode *inode = d_inode(dentry);
1442 int error = 0;
1443
1444 /*
1445 * I believe we can only get a negative dentry here in the case of a
1446 * procfs-style symlink. Just assume it's correct for now, but we may
1447 * eventually need to do something more here.
1448 */
1449 if (!inode) {
1450 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n",
1451 __func__, dentry);
1452 return 1;
1453 }
1454
1455 if (is_bad_inode(inode)) {
1456 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1457 __func__, dentry);
1458 return 0;
1459 }
1460
1461 error = nfs_lookup_verify_inode(inode, flags);
1462 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n",
1463 __func__, inode->i_ino, error ? "invalid" : "valid");
1464 return !error;
1465}
1466
1467/*
1468 * This is called from dput() when d_count is going to 0.
1469 */
1470static int nfs_dentry_delete(const struct dentry *dentry)
1471{
1472 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n",
1473 dentry, dentry->d_flags);
1474
1475 /* Unhash any dentry with a stale inode */
1476 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry)))
1477 return 1;
1478
1479 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1480 /* Unhash it, so that ->d_iput() would be called */
1481 return 1;
1482 }
1483 if (!(dentry->d_sb->s_flags & SB_ACTIVE)) {
1484 /* Unhash it, so that ancestors of killed async unlink
1485 * files will be cleaned up during umount */
1486 return 1;
1487 }
1488 return 0;
1489
1490}
1491
1492/* Ensure that we revalidate inode->i_nlink */
1493static void nfs_drop_nlink(struct inode *inode)
1494{
1495 spin_lock(&inode->i_lock);
1496 /* drop the inode if we're reasonably sure this is the last link */
1497 if (inode->i_nlink > 0)
1498 drop_nlink(inode);
1499 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
1500 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_CHANGE
1501 | NFS_INO_INVALID_CTIME
1502 | NFS_INO_INVALID_OTHER
1503 | NFS_INO_REVAL_FORCED;
1504 spin_unlock(&inode->i_lock);
1505}
1506
1507/*
1508 * Called when the dentry loses inode.
1509 * We use it to clean up silly-renamed files.
1510 */
1511static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
1512{
1513 if (S_ISDIR(inode->i_mode))
1514 /* drop any readdir cache as it could easily be old */
1515 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA;
1516
1517 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1518 nfs_complete_unlink(dentry, inode);
1519 nfs_drop_nlink(inode);
1520 }
1521 iput(inode);
1522}
1523
1524static void nfs_d_release(struct dentry *dentry)
1525{
1526 /* free cached devname value, if it survived that far */
1527 if (unlikely(dentry->d_fsdata)) {
1528 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
1529 WARN_ON(1);
1530 else
1531 kfree(dentry->d_fsdata);
1532 }
1533}
1534
1535const struct dentry_operations nfs_dentry_operations = {
1536 .d_revalidate = nfs_lookup_revalidate,
1537 .d_weak_revalidate = nfs_weak_revalidate,
1538 .d_delete = nfs_dentry_delete,
1539 .d_iput = nfs_dentry_iput,
1540 .d_automount = nfs_d_automount,
1541 .d_release = nfs_d_release,
1542};
1543EXPORT_SYMBOL_GPL(nfs_dentry_operations);
1544
1545struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
1546{
1547 struct dentry *res;
1548 struct inode *inode = NULL;
1549 struct nfs_fh *fhandle = NULL;
1550 struct nfs_fattr *fattr = NULL;
1551 struct nfs4_label *label = NULL;
1552 unsigned long dir_verifier;
1553 int error;
1554
1555 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry);
1556 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
1557
1558 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen))
1559 return ERR_PTR(-ENAMETOOLONG);
1560
1561 /*
1562 * If we're doing an exclusive create, optimize away the lookup
1563 * but don't hash the dentry.
1564 */
1565 if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET)
1566 return NULL;
1567
1568 res = ERR_PTR(-ENOMEM);
1569 fhandle = nfs_alloc_fhandle();
1570 fattr = nfs_alloc_fattr();
1571 if (fhandle == NULL || fattr == NULL)
1572 goto out;
1573
1574 label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT);
1575 if (IS_ERR(label))
1576 goto out;
1577
1578 dir_verifier = nfs_save_change_attribute(dir);
1579 trace_nfs_lookup_enter(dir, dentry, flags);
1580 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label);
1581 if (error == -ENOENT)
1582 goto no_entry;
1583 if (error < 0) {
1584 res = ERR_PTR(error);
1585 goto out_label;
1586 }
1587 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
1588 res = ERR_CAST(inode);
1589 if (IS_ERR(res))
1590 goto out_label;
1591
1592 /* Notify readdir to use READDIRPLUS */
1593 nfs_force_use_readdirplus(dir);
1594
1595no_entry:
1596 res = d_splice_alias(inode, dentry);
1597 if (res != NULL) {
1598 if (IS_ERR(res))
1599 goto out_label;
1600 dentry = res;
1601 }
1602 nfs_set_verifier(dentry, dir_verifier);
1603out_label:
1604 trace_nfs_lookup_exit(dir, dentry, flags, error);
1605 nfs4_label_free(label);
1606out:
1607 nfs_free_fattr(fattr);
1608 nfs_free_fhandle(fhandle);
1609 return res;
1610}
1611EXPORT_SYMBOL_GPL(nfs_lookup);
1612
1613#if IS_ENABLED(CONFIG_NFS_V4)
1614static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
1615
1616const struct dentry_operations nfs4_dentry_operations = {
1617 .d_revalidate = nfs4_lookup_revalidate,
1618 .d_weak_revalidate = nfs_weak_revalidate,
1619 .d_delete = nfs_dentry_delete,
1620 .d_iput = nfs_dentry_iput,
1621 .d_automount = nfs_d_automount,
1622 .d_release = nfs_d_release,
1623};
1624EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
1625
1626static fmode_t flags_to_mode(int flags)
1627{
1628 fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
1629 if ((flags & O_ACCMODE) != O_WRONLY)
1630 res |= FMODE_READ;
1631 if ((flags & O_ACCMODE) != O_RDONLY)
1632 res |= FMODE_WRITE;
1633 return res;
1634}
1635
1636static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
1637{
1638 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
1639}
1640
1641static int do_open(struct inode *inode, struct file *filp)
1642{
1643 nfs_fscache_open_file(inode, filp);
1644 return 0;
1645}
1646
1647static int nfs_finish_open(struct nfs_open_context *ctx,
1648 struct dentry *dentry,
1649 struct file *file, unsigned open_flags)
1650{
1651 int err;
1652
1653 err = finish_open(file, dentry, do_open);
1654 if (err)
1655 goto out;
1656 if (S_ISREG(file->f_path.dentry->d_inode->i_mode))
1657 nfs_file_set_open_context(file, ctx);
1658 else
1659 err = -EOPENSTALE;
1660out:
1661 return err;
1662}
1663
1664int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
1665 struct file *file, unsigned open_flags,
1666 umode_t mode)
1667{
1668 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1669 struct nfs_open_context *ctx;
1670 struct dentry *res;
1671 struct iattr attr = { .ia_valid = ATTR_OPEN };
1672 struct inode *inode;
1673 unsigned int lookup_flags = 0;
1674 bool switched = false;
1675 int created = 0;
1676 int err;
1677
1678 /* Expect a negative dentry */
1679 BUG_ON(d_inode(dentry));
1680
1681 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n",
1682 dir->i_sb->s_id, dir->i_ino, dentry);
1683
1684 err = nfs_check_flags(open_flags);
1685 if (err)
1686 return err;
1687
1688 /* NFS only supports OPEN on regular files */
1689 if ((open_flags & O_DIRECTORY)) {
1690 if (!d_in_lookup(dentry)) {
1691 /*
1692 * Hashed negative dentry with O_DIRECTORY: dentry was
1693 * revalidated and is fine, no need to perform lookup
1694 * again
1695 */
1696 return -ENOENT;
1697 }
1698 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY;
1699 goto no_open;
1700 }
1701
1702 if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
1703 return -ENAMETOOLONG;
1704
1705 if (open_flags & O_CREAT) {
1706 struct nfs_server *server = NFS_SERVER(dir);
1707
1708 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
1709 mode &= ~current_umask();
1710
1711 attr.ia_valid |= ATTR_MODE;
1712 attr.ia_mode = mode;
1713 }
1714 if (open_flags & O_TRUNC) {
1715 attr.ia_valid |= ATTR_SIZE;
1716 attr.ia_size = 0;
1717 }
1718
1719 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) {
1720 d_drop(dentry);
1721 switched = true;
1722 dentry = d_alloc_parallel(dentry->d_parent,
1723 &dentry->d_name, &wq);
1724 if (IS_ERR(dentry))
1725 return PTR_ERR(dentry);
1726 if (unlikely(!d_in_lookup(dentry)))
1727 return finish_no_open(file, dentry);
1728 }
1729
1730 ctx = create_nfs_open_context(dentry, open_flags, file);
1731 err = PTR_ERR(ctx);
1732 if (IS_ERR(ctx))
1733 goto out;
1734
1735 trace_nfs_atomic_open_enter(dir, ctx, open_flags);
1736 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created);
1737 if (created)
1738 file->f_mode |= FMODE_CREATED;
1739 if (IS_ERR(inode)) {
1740 err = PTR_ERR(inode);
1741 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
1742 put_nfs_open_context(ctx);
1743 d_drop(dentry);
1744 switch (err) {
1745 case -ENOENT:
1746 d_splice_alias(NULL, dentry);
1747 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1748 break;
1749 case -EISDIR:
1750 case -ENOTDIR:
1751 goto no_open;
1752 case -ELOOP:
1753 if (!(open_flags & O_NOFOLLOW))
1754 goto no_open;
1755 break;
1756 /* case -EINVAL: */
1757 default:
1758 break;
1759 }
1760 goto out;
1761 }
1762
1763 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags);
1764 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
1765 put_nfs_open_context(ctx);
1766out:
1767 if (unlikely(switched)) {
1768 d_lookup_done(dentry);
1769 dput(dentry);
1770 }
1771 return err;
1772
1773no_open:
1774 res = nfs_lookup(dir, dentry, lookup_flags);
1775 if (switched) {
1776 d_lookup_done(dentry);
1777 if (!res)
1778 res = dentry;
1779 else
1780 dput(dentry);
1781 }
1782 if (IS_ERR(res))
1783 return PTR_ERR(res);
1784 return finish_no_open(file, res);
1785}
1786EXPORT_SYMBOL_GPL(nfs_atomic_open);
1787
1788static int
1789nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
1790 unsigned int flags)
1791{
1792 struct inode *inode;
1793
1794 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
1795 goto full_reval;
1796 if (d_mountpoint(dentry))
1797 goto full_reval;
1798
1799 inode = d_inode(dentry);
1800
1801 /* We can't create new files in nfs_open_revalidate(), so we
1802 * optimize away revalidation of negative dentries.
1803 */
1804 if (inode == NULL)
1805 goto full_reval;
1806
1807 if (nfs_verifier_is_delegated(dentry))
1808 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
1809
1810 /* NFS only supports OPEN on regular files */
1811 if (!S_ISREG(inode->i_mode))
1812 goto full_reval;
1813
1814 /* We cannot do exclusive creation on a positive dentry */
1815 if (flags & (LOOKUP_EXCL | LOOKUP_REVAL))
1816 goto reval_dentry;
1817
1818 /* Check if the directory changed */
1819 if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU))
1820 goto reval_dentry;
1821
1822 /* Let f_op->open() actually open (and revalidate) the file */
1823 return 1;
1824reval_dentry:
1825 if (flags & LOOKUP_RCU)
1826 return -ECHILD;
1827 return nfs_lookup_revalidate_dentry(dir, dentry, inode);
1828
1829full_reval:
1830 return nfs_do_lookup_revalidate(dir, dentry, flags);
1831}
1832
1833static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
1834{
1835 return __nfs_lookup_revalidate(dentry, flags,
1836 nfs4_do_lookup_revalidate);
1837}
1838
1839#endif /* CONFIG_NFSV4 */
1840
1841struct dentry *
1842nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle,
1843 struct nfs_fattr *fattr,
1844 struct nfs4_label *label)
1845{
1846 struct dentry *parent = dget_parent(dentry);
1847 struct inode *dir = d_inode(parent);
1848 struct inode *inode;
1849 struct dentry *d;
1850 int error;
1851
1852 d_drop(dentry);
1853
1854 if (fhandle->size == 0) {
1855 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, NULL);
1856 if (error)
1857 goto out_error;
1858 }
1859 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1860 if (!(fattr->valid & NFS_ATTR_FATTR)) {
1861 struct nfs_server *server = NFS_SB(dentry->d_sb);
1862 error = server->nfs_client->rpc_ops->getattr(server, fhandle,
1863 fattr, NULL, NULL);
1864 if (error < 0)
1865 goto out_error;
1866 }
1867 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label);
1868 d = d_splice_alias(inode, dentry);
1869out:
1870 dput(parent);
1871 return d;
1872out_error:
1873 nfs_mark_for_revalidate(dir);
1874 d = ERR_PTR(error);
1875 goto out;
1876}
1877EXPORT_SYMBOL_GPL(nfs_add_or_obtain);
1878
1879/*
1880 * Code common to create, mkdir, and mknod.
1881 */
1882int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
1883 struct nfs_fattr *fattr,
1884 struct nfs4_label *label)
1885{
1886 struct dentry *d;
1887
1888 d = nfs_add_or_obtain(dentry, fhandle, fattr, label);
1889 if (IS_ERR(d))
1890 return PTR_ERR(d);
1891
1892 /* Callers don't care */
1893 dput(d);
1894 return 0;
1895}
1896EXPORT_SYMBOL_GPL(nfs_instantiate);
1897
1898/*
1899 * Following a failed create operation, we drop the dentry rather
1900 * than retain a negative dentry. This avoids a problem in the event
1901 * that the operation succeeded on the server, but an error in the
1902 * reply path made it appear to have failed.
1903 */
1904int nfs_create(struct inode *dir, struct dentry *dentry,
1905 umode_t mode, bool excl)
1906{
1907 struct iattr attr;
1908 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT;
1909 int error;
1910
1911 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n",
1912 dir->i_sb->s_id, dir->i_ino, dentry);
1913
1914 attr.ia_mode = mode;
1915 attr.ia_valid = ATTR_MODE;
1916
1917 trace_nfs_create_enter(dir, dentry, open_flags);
1918 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
1919 trace_nfs_create_exit(dir, dentry, open_flags, error);
1920 if (error != 0)
1921 goto out_err;
1922 return 0;
1923out_err:
1924 d_drop(dentry);
1925 return error;
1926}
1927EXPORT_SYMBOL_GPL(nfs_create);
1928
1929/*
1930 * See comments for nfs_proc_create regarding failed operations.
1931 */
1932int
1933nfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1934{
1935 struct iattr attr;
1936 int status;
1937
1938 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n",
1939 dir->i_sb->s_id, dir->i_ino, dentry);
1940
1941 attr.ia_mode = mode;
1942 attr.ia_valid = ATTR_MODE;
1943
1944 trace_nfs_mknod_enter(dir, dentry);
1945 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
1946 trace_nfs_mknod_exit(dir, dentry, status);
1947 if (status != 0)
1948 goto out_err;
1949 return 0;
1950out_err:
1951 d_drop(dentry);
1952 return status;
1953}
1954EXPORT_SYMBOL_GPL(nfs_mknod);
1955
1956/*
1957 * See comments for nfs_proc_create regarding failed operations.
1958 */
1959int nfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
1960{
1961 struct iattr attr;
1962 int error;
1963
1964 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n",
1965 dir->i_sb->s_id, dir->i_ino, dentry);
1966
1967 attr.ia_valid = ATTR_MODE;
1968 attr.ia_mode = mode | S_IFDIR;
1969
1970 trace_nfs_mkdir_enter(dir, dentry);
1971 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
1972 trace_nfs_mkdir_exit(dir, dentry, error);
1973 if (error != 0)
1974 goto out_err;
1975 return 0;
1976out_err:
1977 d_drop(dentry);
1978 return error;
1979}
1980EXPORT_SYMBOL_GPL(nfs_mkdir);
1981
1982static void nfs_dentry_handle_enoent(struct dentry *dentry)
1983{
1984 if (simple_positive(dentry))
1985 d_delete(dentry);
1986}
1987
1988int nfs_rmdir(struct inode *dir, struct dentry *dentry)
1989{
1990 int error;
1991
1992 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n",
1993 dir->i_sb->s_id, dir->i_ino, dentry);
1994
1995 trace_nfs_rmdir_enter(dir, dentry);
1996 if (d_really_is_positive(dentry)) {
1997 down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
1998 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
1999 /* Ensure the VFS deletes this inode */
2000 switch (error) {
2001 case 0:
2002 clear_nlink(d_inode(dentry));
2003 break;
2004 case -ENOENT:
2005 nfs_dentry_handle_enoent(dentry);
2006 }
2007 up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
2008 } else
2009 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
2010 trace_nfs_rmdir_exit(dir, dentry, error);
2011
2012 return error;
2013}
2014EXPORT_SYMBOL_GPL(nfs_rmdir);
2015
2016/*
2017 * Remove a file after making sure there are no pending writes,
2018 * and after checking that the file has only one user.
2019 *
2020 * We invalidate the attribute cache and free the inode prior to the operation
2021 * to avoid possible races if the server reuses the inode.
2022 */
2023static int nfs_safe_remove(struct dentry *dentry)
2024{
2025 struct inode *dir = d_inode(dentry->d_parent);
2026 struct inode *inode = d_inode(dentry);
2027 int error = -EBUSY;
2028
2029 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry);
2030
2031 /* If the dentry was sillyrenamed, we simply call d_delete() */
2032 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
2033 error = 0;
2034 goto out;
2035 }
2036
2037 trace_nfs_remove_enter(dir, dentry);
2038 if (inode != NULL) {
2039 error = NFS_PROTO(dir)->remove(dir, dentry);
2040 if (error == 0)
2041 nfs_drop_nlink(inode);
2042 } else
2043 error = NFS_PROTO(dir)->remove(dir, dentry);
2044 if (error == -ENOENT)
2045 nfs_dentry_handle_enoent(dentry);
2046 trace_nfs_remove_exit(dir, dentry, error);
2047out:
2048 return error;
2049}
2050
2051/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
2052 * belongs to an active ".nfs..." file and we return -EBUSY.
2053 *
2054 * If sillyrename() returns 0, we do nothing, otherwise we unlink.
2055 */
2056int nfs_unlink(struct inode *dir, struct dentry *dentry)
2057{
2058 int error;
2059 int need_rehash = 0;
2060
2061 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id,
2062 dir->i_ino, dentry);
2063
2064 trace_nfs_unlink_enter(dir, dentry);
2065 spin_lock(&dentry->d_lock);
2066 if (d_count(dentry) > 1) {
2067 spin_unlock(&dentry->d_lock);
2068 /* Start asynchronous writeout of the inode */
2069 write_inode_now(d_inode(dentry), 0);
2070 error = nfs_sillyrename(dir, dentry);
2071 goto out;
2072 }
2073 if (!d_unhashed(dentry)) {
2074 __d_drop(dentry);
2075 need_rehash = 1;
2076 }
2077 spin_unlock(&dentry->d_lock);
2078 error = nfs_safe_remove(dentry);
2079 if (!error || error == -ENOENT) {
2080 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2081 } else if (need_rehash)
2082 d_rehash(dentry);
2083out:
2084 trace_nfs_unlink_exit(dir, dentry, error);
2085 return error;
2086}
2087EXPORT_SYMBOL_GPL(nfs_unlink);
2088
2089/*
2090 * To create a symbolic link, most file systems instantiate a new inode,
2091 * add a page to it containing the path, then write it out to the disk
2092 * using prepare_write/commit_write.
2093 *
2094 * Unfortunately the NFS client can't create the in-core inode first
2095 * because it needs a file handle to create an in-core inode (see
2096 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the
2097 * symlink request has completed on the server.
2098 *
2099 * So instead we allocate a raw page, copy the symname into it, then do
2100 * the SYMLINK request with the page as the buffer. If it succeeds, we
2101 * now have a new file handle and can instantiate an in-core NFS inode
2102 * and move the raw page into its mapping.
2103 */
2104int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
2105{
2106 struct page *page;
2107 char *kaddr;
2108 struct iattr attr;
2109 unsigned int pathlen = strlen(symname);
2110 int error;
2111
2112 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id,
2113 dir->i_ino, dentry, symname);
2114
2115 if (pathlen > PAGE_SIZE)
2116 return -ENAMETOOLONG;
2117
2118 attr.ia_mode = S_IFLNK | S_IRWXUGO;
2119 attr.ia_valid = ATTR_MODE;
2120
2121 page = alloc_page(GFP_USER);
2122 if (!page)
2123 return -ENOMEM;
2124
2125 kaddr = page_address(page);
2126 memcpy(kaddr, symname, pathlen);
2127 if (pathlen < PAGE_SIZE)
2128 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
2129
2130 trace_nfs_symlink_enter(dir, dentry);
2131 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
2132 trace_nfs_symlink_exit(dir, dentry, error);
2133 if (error != 0) {
2134 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n",
2135 dir->i_sb->s_id, dir->i_ino,
2136 dentry, symname, error);
2137 d_drop(dentry);
2138 __free_page(page);
2139 return error;
2140 }
2141
2142 /*
2143 * No big deal if we can't add this page to the page cache here.
2144 * READLINK will get the missing page from the server if needed.
2145 */
2146 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0,
2147 GFP_KERNEL)) {
2148 SetPageUptodate(page);
2149 unlock_page(page);
2150 /*
2151 * add_to_page_cache_lru() grabs an extra page refcount.
2152 * Drop it here to avoid leaking this page later.
2153 */
2154 put_page(page);
2155 } else
2156 __free_page(page);
2157
2158 return 0;
2159}
2160EXPORT_SYMBOL_GPL(nfs_symlink);
2161
2162int
2163nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
2164{
2165 struct inode *inode = d_inode(old_dentry);
2166 int error;
2167
2168 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n",
2169 old_dentry, dentry);
2170
2171 trace_nfs_link_enter(inode, dir, dentry);
2172 d_drop(dentry);
2173 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
2174 if (error == 0) {
2175 ihold(inode);
2176 d_add(dentry, inode);
2177 }
2178 trace_nfs_link_exit(inode, dir, dentry, error);
2179 return error;
2180}
2181EXPORT_SYMBOL_GPL(nfs_link);
2182
2183/*
2184 * RENAME
2185 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
2186 * different file handle for the same inode after a rename (e.g. when
2187 * moving to a different directory). A fail-safe method to do so would
2188 * be to look up old_dir/old_name, create a link to new_dir/new_name and
2189 * rename the old file using the sillyrename stuff. This way, the original
2190 * file in old_dir will go away when the last process iput()s the inode.
2191 *
2192 * FIXED.
2193 *
2194 * It actually works quite well. One needs to have the possibility for
2195 * at least one ".nfs..." file in each directory the file ever gets
2196 * moved or linked to which happens automagically with the new
2197 * implementation that only depends on the dcache stuff instead of
2198 * using the inode layer
2199 *
2200 * Unfortunately, things are a little more complicated than indicated
2201 * above. For a cross-directory move, we want to make sure we can get
2202 * rid of the old inode after the operation. This means there must be
2203 * no pending writes (if it's a file), and the use count must be 1.
2204 * If these conditions are met, we can drop the dentries before doing
2205 * the rename.
2206 */
2207int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
2208 struct inode *new_dir, struct dentry *new_dentry,
2209 unsigned int flags)
2210{
2211 struct inode *old_inode = d_inode(old_dentry);
2212 struct inode *new_inode = d_inode(new_dentry);
2213 struct dentry *dentry = NULL, *rehash = NULL;
2214 struct rpc_task *task;
2215 int error = -EBUSY;
2216
2217 if (flags)
2218 return -EINVAL;
2219
2220 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n",
2221 old_dentry, new_dentry,
2222 d_count(new_dentry));
2223
2224 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry);
2225 /*
2226 * For non-directories, check whether the target is busy and if so,
2227 * make a copy of the dentry and then do a silly-rename. If the
2228 * silly-rename succeeds, the copied dentry is hashed and becomes
2229 * the new target.
2230 */
2231 if (new_inode && !S_ISDIR(new_inode->i_mode)) {
2232 /*
2233 * To prevent any new references to the target during the
2234 * rename, we unhash the dentry in advance.
2235 */
2236 if (!d_unhashed(new_dentry)) {
2237 d_drop(new_dentry);
2238 rehash = new_dentry;
2239 }
2240
2241 if (d_count(new_dentry) > 2) {
2242 int err;
2243
2244 /* copy the target dentry's name */
2245 dentry = d_alloc(new_dentry->d_parent,
2246 &new_dentry->d_name);
2247 if (!dentry)
2248 goto out;
2249
2250 /* silly-rename the existing target ... */
2251 err = nfs_sillyrename(new_dir, new_dentry);
2252 if (err)
2253 goto out;
2254
2255 new_dentry = dentry;
2256 rehash = NULL;
2257 new_inode = NULL;
2258 }
2259 }
2260
2261 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL);
2262 if (IS_ERR(task)) {
2263 error = PTR_ERR(task);
2264 goto out;
2265 }
2266
2267 error = rpc_wait_for_completion_task(task);
2268 if (error != 0) {
2269 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1;
2270 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */
2271 smp_wmb();
2272 } else
2273 error = task->tk_status;
2274 rpc_put_task(task);
2275 /* Ensure the inode attributes are revalidated */
2276 if (error == 0) {
2277 spin_lock(&old_inode->i_lock);
2278 NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter();
2279 NFS_I(old_inode)->cache_validity |= NFS_INO_INVALID_CHANGE
2280 | NFS_INO_INVALID_CTIME
2281 | NFS_INO_REVAL_FORCED;
2282 spin_unlock(&old_inode->i_lock);
2283 }
2284out:
2285 if (rehash)
2286 d_rehash(rehash);
2287 trace_nfs_rename_exit(old_dir, old_dentry,
2288 new_dir, new_dentry, error);
2289 if (!error) {
2290 if (new_inode != NULL)
2291 nfs_drop_nlink(new_inode);
2292 /*
2293 * The d_move() should be here instead of in an async RPC completion
2294 * handler because we need the proper locks to move the dentry. If
2295 * we're interrupted by a signal, the async RPC completion handler
2296 * should mark the directories for revalidation.
2297 */
2298 d_move(old_dentry, new_dentry);
2299 nfs_set_verifier(old_dentry,
2300 nfs_save_change_attribute(new_dir));
2301 } else if (error == -ENOENT)
2302 nfs_dentry_handle_enoent(old_dentry);
2303
2304 /* new dentry created? */
2305 if (dentry)
2306 dput(dentry);
2307 return error;
2308}
2309EXPORT_SYMBOL_GPL(nfs_rename);
2310
2311static DEFINE_SPINLOCK(nfs_access_lru_lock);
2312static LIST_HEAD(nfs_access_lru_list);
2313static atomic_long_t nfs_access_nr_entries;
2314
2315static unsigned long nfs_access_max_cachesize = 4*1024*1024;
2316module_param(nfs_access_max_cachesize, ulong, 0644);
2317MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length");
2318
2319static void nfs_access_free_entry(struct nfs_access_entry *entry)
2320{
2321 put_cred(entry->cred);
2322 kfree_rcu(entry, rcu_head);
2323 smp_mb__before_atomic();
2324 atomic_long_dec(&nfs_access_nr_entries);
2325 smp_mb__after_atomic();
2326}
2327
2328static void nfs_access_free_list(struct list_head *head)
2329{
2330 struct nfs_access_entry *cache;
2331
2332 while (!list_empty(head)) {
2333 cache = list_entry(head->next, struct nfs_access_entry, lru);
2334 list_del(&cache->lru);
2335 nfs_access_free_entry(cache);
2336 }
2337}
2338
2339static unsigned long
2340nfs_do_access_cache_scan(unsigned int nr_to_scan)
2341{
2342 LIST_HEAD(head);
2343 struct nfs_inode *nfsi, *next;
2344 struct nfs_access_entry *cache;
2345 long freed = 0;
2346
2347 spin_lock(&nfs_access_lru_lock);
2348 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) {
2349 struct inode *inode;
2350
2351 if (nr_to_scan-- == 0)
2352 break;
2353 inode = &nfsi->vfs_inode;
2354 spin_lock(&inode->i_lock);
2355 if (list_empty(&nfsi->access_cache_entry_lru))
2356 goto remove_lru_entry;
2357 cache = list_entry(nfsi->access_cache_entry_lru.next,
2358 struct nfs_access_entry, lru);
2359 list_move(&cache->lru, &head);
2360 rb_erase(&cache->rb_node, &nfsi->access_cache);
2361 freed++;
2362 if (!list_empty(&nfsi->access_cache_entry_lru))
2363 list_move_tail(&nfsi->access_cache_inode_lru,
2364 &nfs_access_lru_list);
2365 else {
2366remove_lru_entry:
2367 list_del_init(&nfsi->access_cache_inode_lru);
2368 smp_mb__before_atomic();
2369 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
2370 smp_mb__after_atomic();
2371 }
2372 spin_unlock(&inode->i_lock);
2373 }
2374 spin_unlock(&nfs_access_lru_lock);
2375 nfs_access_free_list(&head);
2376 return freed;
2377}
2378
2379unsigned long
2380nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
2381{
2382 int nr_to_scan = sc->nr_to_scan;
2383 gfp_t gfp_mask = sc->gfp_mask;
2384
2385 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
2386 return SHRINK_STOP;
2387 return nfs_do_access_cache_scan(nr_to_scan);
2388}
2389
2390
2391unsigned long
2392nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc)
2393{
2394 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries));
2395}
2396
2397static void
2398nfs_access_cache_enforce_limit(void)
2399{
2400 long nr_entries = atomic_long_read(&nfs_access_nr_entries);
2401 unsigned long diff;
2402 unsigned int nr_to_scan;
2403
2404 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize)
2405 return;
2406 nr_to_scan = 100;
2407 diff = nr_entries - nfs_access_max_cachesize;
2408 if (diff < nr_to_scan)
2409 nr_to_scan = diff;
2410 nfs_do_access_cache_scan(nr_to_scan);
2411}
2412
2413static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head)
2414{
2415 struct rb_root *root_node = &nfsi->access_cache;
2416 struct rb_node *n;
2417 struct nfs_access_entry *entry;
2418
2419 /* Unhook entries from the cache */
2420 while ((n = rb_first(root_node)) != NULL) {
2421 entry = rb_entry(n, struct nfs_access_entry, rb_node);
2422 rb_erase(n, root_node);
2423 list_move(&entry->lru, head);
2424 }
2425 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
2426}
2427
2428void nfs_access_zap_cache(struct inode *inode)
2429{
2430 LIST_HEAD(head);
2431
2432 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0)
2433 return;
2434 /* Remove from global LRU init */
2435 spin_lock(&nfs_access_lru_lock);
2436 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
2437 list_del_init(&NFS_I(inode)->access_cache_inode_lru);
2438
2439 spin_lock(&inode->i_lock);
2440 __nfs_access_zap_cache(NFS_I(inode), &head);
2441 spin_unlock(&inode->i_lock);
2442 spin_unlock(&nfs_access_lru_lock);
2443 nfs_access_free_list(&head);
2444}
2445EXPORT_SYMBOL_GPL(nfs_access_zap_cache);
2446
2447static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred)
2448{
2449 struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
2450
2451 while (n != NULL) {
2452 struct nfs_access_entry *entry =
2453 rb_entry(n, struct nfs_access_entry, rb_node);
2454 int cmp = cred_fscmp(cred, entry->cred);
2455
2456 if (cmp < 0)
2457 n = n->rb_left;
2458 else if (cmp > 0)
2459 n = n->rb_right;
2460 else
2461 return entry;
2462 }
2463 return NULL;
2464}
2465
2466static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res, bool may_block)
2467{
2468 struct nfs_inode *nfsi = NFS_I(inode);
2469 struct nfs_access_entry *cache;
2470 bool retry = true;
2471 int err;
2472
2473 spin_lock(&inode->i_lock);
2474 for(;;) {
2475 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2476 goto out_zap;
2477 cache = nfs_access_search_rbtree(inode, cred);
2478 err = -ENOENT;
2479 if (cache == NULL)
2480 goto out;
2481 /* Found an entry, is our attribute cache valid? */
2482 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2483 break;
2484 if (!retry)
2485 break;
2486 err = -ECHILD;
2487 if (!may_block)
2488 goto out;
2489 spin_unlock(&inode->i_lock);
2490 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
2491 if (err)
2492 return err;
2493 spin_lock(&inode->i_lock);
2494 retry = false;
2495 }
2496 res->cred = cache->cred;
2497 res->mask = cache->mask;
2498 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
2499 err = 0;
2500out:
2501 spin_unlock(&inode->i_lock);
2502 return err;
2503out_zap:
2504 spin_unlock(&inode->i_lock);
2505 nfs_access_zap_cache(inode);
2506 return -ENOENT;
2507}
2508
2509static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res)
2510{
2511 /* Only check the most recently returned cache entry,
2512 * but do it without locking.
2513 */
2514 struct nfs_inode *nfsi = NFS_I(inode);
2515 struct nfs_access_entry *cache;
2516 int err = -ECHILD;
2517 struct list_head *lh;
2518
2519 rcu_read_lock();
2520 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2521 goto out;
2522 lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru));
2523 cache = list_entry(lh, struct nfs_access_entry, lru);
2524 if (lh == &nfsi->access_cache_entry_lru ||
2525 cred_fscmp(cred, cache->cred) != 0)
2526 cache = NULL;
2527 if (cache == NULL)
2528 goto out;
2529 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2530 goto out;
2531 res->cred = cache->cred;
2532 res->mask = cache->mask;
2533 err = 0;
2534out:
2535 rcu_read_unlock();
2536 return err;
2537}
2538
2539int nfs_access_get_cached(struct inode *inode, const struct cred *cred, struct
2540nfs_access_entry *res, bool may_block)
2541{
2542 int status;
2543
2544 status = nfs_access_get_cached_rcu(inode, cred, res);
2545 if (status != 0)
2546 status = nfs_access_get_cached_locked(inode, cred, res,
2547 may_block);
2548
2549 return status;
2550}
2551EXPORT_SYMBOL_GPL(nfs_access_get_cached);
2552
2553static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set)
2554{
2555 struct nfs_inode *nfsi = NFS_I(inode);
2556 struct rb_root *root_node = &nfsi->access_cache;
2557 struct rb_node **p = &root_node->rb_node;
2558 struct rb_node *parent = NULL;
2559 struct nfs_access_entry *entry;
2560 int cmp;
2561
2562 spin_lock(&inode->i_lock);
2563 while (*p != NULL) {
2564 parent = *p;
2565 entry = rb_entry(parent, struct nfs_access_entry, rb_node);
2566 cmp = cred_fscmp(set->cred, entry->cred);
2567
2568 if (cmp < 0)
2569 p = &parent->rb_left;
2570 else if (cmp > 0)
2571 p = &parent->rb_right;
2572 else
2573 goto found;
2574 }
2575 rb_link_node(&set->rb_node, parent, p);
2576 rb_insert_color(&set->rb_node, root_node);
2577 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
2578 spin_unlock(&inode->i_lock);
2579 return;
2580found:
2581 rb_replace_node(parent, &set->rb_node, root_node);
2582 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
2583 list_del(&entry->lru);
2584 spin_unlock(&inode->i_lock);
2585 nfs_access_free_entry(entry);
2586}
2587
2588void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
2589{
2590 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
2591 if (cache == NULL)
2592 return;
2593 RB_CLEAR_NODE(&cache->rb_node);
2594 cache->cred = get_cred(set->cred);
2595 cache->mask = set->mask;
2596
2597 /* The above field assignments must be visible
2598 * before this item appears on the lru. We cannot easily
2599 * use rcu_assign_pointer, so just force the memory barrier.
2600 */
2601 smp_wmb();
2602 nfs_access_add_rbtree(inode, cache);
2603
2604 /* Update accounting */
2605 smp_mb__before_atomic();
2606 atomic_long_inc(&nfs_access_nr_entries);
2607 smp_mb__after_atomic();
2608
2609 /* Add inode to global LRU list */
2610 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) {
2611 spin_lock(&nfs_access_lru_lock);
2612 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
2613 list_add_tail(&NFS_I(inode)->access_cache_inode_lru,
2614 &nfs_access_lru_list);
2615 spin_unlock(&nfs_access_lru_lock);
2616 }
2617 nfs_access_cache_enforce_limit();
2618}
2619EXPORT_SYMBOL_GPL(nfs_access_add_cache);
2620
2621#define NFS_MAY_READ (NFS_ACCESS_READ)
2622#define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \
2623 NFS_ACCESS_EXTEND | \
2624 NFS_ACCESS_DELETE)
2625#define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \
2626 NFS_ACCESS_EXTEND)
2627#define NFS_DIR_MAY_WRITE NFS_MAY_WRITE
2628#define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP)
2629#define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE)
2630static int
2631nfs_access_calc_mask(u32 access_result, umode_t umode)
2632{
2633 int mask = 0;
2634
2635 if (access_result & NFS_MAY_READ)
2636 mask |= MAY_READ;
2637 if (S_ISDIR(umode)) {
2638 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE)
2639 mask |= MAY_WRITE;
2640 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP)
2641 mask |= MAY_EXEC;
2642 } else if (S_ISREG(umode)) {
2643 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE)
2644 mask |= MAY_WRITE;
2645 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE)
2646 mask |= MAY_EXEC;
2647 } else if (access_result & NFS_MAY_WRITE)
2648 mask |= MAY_WRITE;
2649 return mask;
2650}
2651
2652void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result)
2653{
2654 entry->mask = access_result;
2655}
2656EXPORT_SYMBOL_GPL(nfs_access_set_mask);
2657
2658static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask)
2659{
2660 struct nfs_access_entry cache;
2661 bool may_block = (mask & MAY_NOT_BLOCK) == 0;
2662 int cache_mask = -1;
2663 int status;
2664
2665 trace_nfs_access_enter(inode);
2666
2667 status = nfs_access_get_cached(inode, cred, &cache, may_block);
2668 if (status == 0)
2669 goto out_cached;
2670
2671 status = -ECHILD;
2672 if (!may_block)
2673 goto out;
2674
2675 /*
2676 * Determine which access bits we want to ask for...
2677 */
2678 cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND;
2679 if (nfs_server_capable(inode, NFS_CAP_XATTR)) {
2680 cache.mask |= NFS_ACCESS_XAREAD | NFS_ACCESS_XAWRITE |
2681 NFS_ACCESS_XALIST;
2682 }
2683 if (S_ISDIR(inode->i_mode))
2684 cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
2685 else
2686 cache.mask |= NFS_ACCESS_EXECUTE;
2687 cache.cred = cred;
2688 status = NFS_PROTO(inode)->access(inode, &cache);
2689 if (status != 0) {
2690 if (status == -ESTALE) {
2691 if (!S_ISDIR(inode->i_mode))
2692 nfs_set_inode_stale(inode);
2693 else
2694 nfs_zap_caches(inode);
2695 }
2696 goto out;
2697 }
2698 nfs_access_add_cache(inode, &cache);
2699out_cached:
2700 cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode);
2701 if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
2702 status = -EACCES;
2703out:
2704 trace_nfs_access_exit(inode, mask, cache_mask, status);
2705 return status;
2706}
2707
2708static int nfs_open_permission_mask(int openflags)
2709{
2710 int mask = 0;
2711
2712 if (openflags & __FMODE_EXEC) {
2713 /* ONLY check exec rights */
2714 mask = MAY_EXEC;
2715 } else {
2716 if ((openflags & O_ACCMODE) != O_WRONLY)
2717 mask |= MAY_READ;
2718 if ((openflags & O_ACCMODE) != O_RDONLY)
2719 mask |= MAY_WRITE;
2720 }
2721
2722 return mask;
2723}
2724
2725int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags)
2726{
2727 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags));
2728}
2729EXPORT_SYMBOL_GPL(nfs_may_open);
2730
2731static int nfs_execute_ok(struct inode *inode, int mask)
2732{
2733 struct nfs_server *server = NFS_SERVER(inode);
2734 int ret = 0;
2735
2736 if (S_ISDIR(inode->i_mode))
2737 return 0;
2738 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_OTHER)) {
2739 if (mask & MAY_NOT_BLOCK)
2740 return -ECHILD;
2741 ret = __nfs_revalidate_inode(server, inode);
2742 }
2743 if (ret == 0 && !execute_ok(inode))
2744 ret = -EACCES;
2745 return ret;
2746}
2747
2748int nfs_permission(struct inode *inode, int mask)
2749{
2750 const struct cred *cred = current_cred();
2751 int res = 0;
2752
2753 nfs_inc_stats(inode, NFSIOS_VFSACCESS);
2754
2755 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
2756 goto out;
2757 /* Is this sys_access() ? */
2758 if (mask & (MAY_ACCESS | MAY_CHDIR))
2759 goto force_lookup;
2760
2761 switch (inode->i_mode & S_IFMT) {
2762 case S_IFLNK:
2763 goto out;
2764 case S_IFREG:
2765 if ((mask & MAY_OPEN) &&
2766 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN))
2767 return 0;
2768 break;
2769 case S_IFDIR:
2770 /*
2771 * Optimize away all write operations, since the server
2772 * will check permissions when we perform the op.
2773 */
2774 if ((mask & MAY_WRITE) && !(mask & MAY_READ))
2775 goto out;
2776 }
2777
2778force_lookup:
2779 if (!NFS_PROTO(inode)->access)
2780 goto out_notsup;
2781
2782 res = nfs_do_access(inode, cred, mask);
2783out:
2784 if (!res && (mask & MAY_EXEC))
2785 res = nfs_execute_ok(inode, mask);
2786
2787 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n",
2788 inode->i_sb->s_id, inode->i_ino, mask, res);
2789 return res;
2790out_notsup:
2791 if (mask & MAY_NOT_BLOCK)
2792 return -ECHILD;
2793
2794 res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
2795 if (res == 0)
2796 res = generic_permission(inode, mask);
2797 goto out;
2798}
2799EXPORT_SYMBOL_GPL(nfs_permission);
2800
2801/*
2802 * Local variables:
2803 * version-control: t
2804 * kept-new-versions: 5
2805 * End:
2806 */