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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/nfs/dir.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/nfs/dir.c')
-rw-r--r--fs/nfs/dir.c1562
1 files changed, 1562 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
new file mode 100644
index 000000000000..73f96acd5d37
--- /dev/null
+++ b/fs/nfs/dir.c
@@ -0,0 +1,1562 @@
1/*
2 * linux/fs/nfs/dir.c
3 *
4 * Copyright (C) 1992 Rick Sladkey
5 *
6 * nfs directory handling functions
7 *
8 * 10 Apr 1996 Added silly rename for unlink --okir
9 * 28 Sep 1996 Improved directory cache --okir
10 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de
11 * Re-implemented silly rename for unlink, newly implemented
12 * silly rename for nfs_rename() following the suggestions
13 * of Olaf Kirch (okir) found in this file.
14 * Following Linus comments on my original hack, this version
15 * depends only on the dcache stuff and doesn't touch the inode
16 * layer (iput() and friends).
17 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM
18 */
19
20#include <linux/time.h>
21#include <linux/errno.h>
22#include <linux/stat.h>
23#include <linux/fcntl.h>
24#include <linux/string.h>
25#include <linux/kernel.h>
26#include <linux/slab.h>
27#include <linux/mm.h>
28#include <linux/sunrpc/clnt.h>
29#include <linux/nfs_fs.h>
30#include <linux/nfs_mount.h>
31#include <linux/pagemap.h>
32#include <linux/smp_lock.h>
33#include <linux/namei.h>
34
35#include "delegation.h"
36
37#define NFS_PARANOIA 1
38/* #define NFS_DEBUG_VERBOSE 1 */
39
40static int nfs_opendir(struct inode *, struct file *);
41static int nfs_readdir(struct file *, void *, filldir_t);
42static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *);
43static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *);
44static int nfs_mkdir(struct inode *, struct dentry *, int);
45static int nfs_rmdir(struct inode *, struct dentry *);
46static int nfs_unlink(struct inode *, struct dentry *);
47static int nfs_symlink(struct inode *, struct dentry *, const char *);
48static int nfs_link(struct dentry *, struct inode *, struct dentry *);
49static int nfs_mknod(struct inode *, struct dentry *, int, dev_t);
50static int nfs_rename(struct inode *, struct dentry *,
51 struct inode *, struct dentry *);
52static int nfs_fsync_dir(struct file *, struct dentry *, int);
53
54struct file_operations nfs_dir_operations = {
55 .read = generic_read_dir,
56 .readdir = nfs_readdir,
57 .open = nfs_opendir,
58 .release = nfs_release,
59 .fsync = nfs_fsync_dir,
60};
61
62struct inode_operations nfs_dir_inode_operations = {
63 .create = nfs_create,
64 .lookup = nfs_lookup,
65 .link = nfs_link,
66 .unlink = nfs_unlink,
67 .symlink = nfs_symlink,
68 .mkdir = nfs_mkdir,
69 .rmdir = nfs_rmdir,
70 .mknod = nfs_mknod,
71 .rename = nfs_rename,
72 .permission = nfs_permission,
73 .getattr = nfs_getattr,
74 .setattr = nfs_setattr,
75};
76
77#ifdef CONFIG_NFS_V4
78
79static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *);
80struct inode_operations nfs4_dir_inode_operations = {
81 .create = nfs_create,
82 .lookup = nfs_atomic_lookup,
83 .link = nfs_link,
84 .unlink = nfs_unlink,
85 .symlink = nfs_symlink,
86 .mkdir = nfs_mkdir,
87 .rmdir = nfs_rmdir,
88 .mknod = nfs_mknod,
89 .rename = nfs_rename,
90 .permission = nfs_permission,
91 .getattr = nfs_getattr,
92 .setattr = nfs_setattr,
93};
94
95#endif /* CONFIG_NFS_V4 */
96
97/*
98 * Open file
99 */
100static int
101nfs_opendir(struct inode *inode, struct file *filp)
102{
103 int res = 0;
104
105 lock_kernel();
106 /* Call generic open code in order to cache credentials */
107 if (!res)
108 res = nfs_open(inode, filp);
109 unlock_kernel();
110 return res;
111}
112
113typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int);
114typedef struct {
115 struct file *file;
116 struct page *page;
117 unsigned long page_index;
118 u32 *ptr;
119 u64 target;
120 struct nfs_entry *entry;
121 decode_dirent_t decode;
122 int plus;
123 int error;
124} nfs_readdir_descriptor_t;
125
126/* Now we cache directories properly, by stuffing the dirent
127 * data directly in the page cache.
128 *
129 * Inode invalidation due to refresh etc. takes care of
130 * _everything_, no sloppy entry flushing logic, no extraneous
131 * copying, network direct to page cache, the way it was meant
132 * to be.
133 *
134 * NOTE: Dirent information verification is done always by the
135 * page-in of the RPC reply, nowhere else, this simplies
136 * things substantially.
137 */
138static
139int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
140{
141 struct file *file = desc->file;
142 struct inode *inode = file->f_dentry->d_inode;
143 struct rpc_cred *cred = nfs_file_cred(file);
144 unsigned long timestamp;
145 int error;
146
147 dfprintk(VFS, "NFS: nfs_readdir_filler() reading cookie %Lu into page %lu.\n", (long long)desc->entry->cookie, page->index);
148
149 again:
150 timestamp = jiffies;
151 error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page,
152 NFS_SERVER(inode)->dtsize, desc->plus);
153 if (error < 0) {
154 /* We requested READDIRPLUS, but the server doesn't grok it */
155 if (error == -ENOTSUPP && desc->plus) {
156 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
157 NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
158 desc->plus = 0;
159 goto again;
160 }
161 goto error;
162 }
163 SetPageUptodate(page);
164 NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
165 /* Ensure consistent page alignment of the data.
166 * Note: assumes we have exclusive access to this mapping either
167 * throught inode->i_sem or some other mechanism.
168 */
169 if (page->index == 0) {
170 invalidate_inode_pages(inode->i_mapping);
171 NFS_I(inode)->readdir_timestamp = timestamp;
172 }
173 unlock_page(page);
174 return 0;
175 error:
176 SetPageError(page);
177 unlock_page(page);
178 nfs_zap_caches(inode);
179 desc->error = error;
180 return -EIO;
181}
182
183static inline
184int dir_decode(nfs_readdir_descriptor_t *desc)
185{
186 u32 *p = desc->ptr;
187 p = desc->decode(p, desc->entry, desc->plus);
188 if (IS_ERR(p))
189 return PTR_ERR(p);
190 desc->ptr = p;
191 return 0;
192}
193
194static inline
195void dir_page_release(nfs_readdir_descriptor_t *desc)
196{
197 kunmap(desc->page);
198 page_cache_release(desc->page);
199 desc->page = NULL;
200 desc->ptr = NULL;
201}
202
203/*
204 * Given a pointer to a buffer that has already been filled by a call
205 * to readdir, find the next entry.
206 *
207 * If the end of the buffer has been reached, return -EAGAIN, if not,
208 * return the offset within the buffer of the next entry to be
209 * read.
210 */
211static inline
212int find_dirent(nfs_readdir_descriptor_t *desc, struct page *page)
213{
214 struct nfs_entry *entry = desc->entry;
215 int loop_count = 0,
216 status;
217
218 while((status = dir_decode(desc)) == 0) {
219 dfprintk(VFS, "NFS: found cookie %Lu\n", (long long)entry->cookie);
220 if (entry->prev_cookie == desc->target)
221 break;
222 if (loop_count++ > 200) {
223 loop_count = 0;
224 schedule();
225 }
226 }
227 dfprintk(VFS, "NFS: find_dirent() returns %d\n", status);
228 return status;
229}
230
231/*
232 * Find the given page, and call find_dirent() in order to try to
233 * return the next entry.
234 */
235static inline
236int find_dirent_page(nfs_readdir_descriptor_t *desc)
237{
238 struct inode *inode = desc->file->f_dentry->d_inode;
239 struct page *page;
240 int status;
241
242 dfprintk(VFS, "NFS: find_dirent_page() searching directory page %ld\n", desc->page_index);
243
244 page = read_cache_page(inode->i_mapping, desc->page_index,
245 (filler_t *)nfs_readdir_filler, desc);
246 if (IS_ERR(page)) {
247 status = PTR_ERR(page);
248 goto out;
249 }
250 if (!PageUptodate(page))
251 goto read_error;
252
253 /* NOTE: Someone else may have changed the READDIRPLUS flag */
254 desc->page = page;
255 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
256 status = find_dirent(desc, page);
257 if (status < 0)
258 dir_page_release(desc);
259 out:
260 dfprintk(VFS, "NFS: find_dirent_page() returns %d\n", status);
261 return status;
262 read_error:
263 page_cache_release(page);
264 return -EIO;
265}
266
267/*
268 * Recurse through the page cache pages, and return a
269 * filled nfs_entry structure of the next directory entry if possible.
270 *
271 * The target for the search is 'desc->target'.
272 */
273static inline
274int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
275{
276 int loop_count = 0;
277 int res;
278
279 dfprintk(VFS, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", (long long)desc->target);
280 for (;;) {
281 res = find_dirent_page(desc);
282 if (res != -EAGAIN)
283 break;
284 /* Align to beginning of next page */
285 desc->page_index ++;
286 if (loop_count++ > 200) {
287 loop_count = 0;
288 schedule();
289 }
290 }
291 dfprintk(VFS, "NFS: readdir_search_pagecache() returned %d\n", res);
292 return res;
293}
294
295static inline unsigned int dt_type(struct inode *inode)
296{
297 return (inode->i_mode >> 12) & 15;
298}
299
300static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc);
301
302/*
303 * Once we've found the start of the dirent within a page: fill 'er up...
304 */
305static
306int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
307 filldir_t filldir)
308{
309 struct file *file = desc->file;
310 struct nfs_entry *entry = desc->entry;
311 struct dentry *dentry = NULL;
312 unsigned long fileid;
313 int loop_count = 0,
314 res;
315
316 dfprintk(VFS, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", (long long)desc->target);
317
318 for(;;) {
319 unsigned d_type = DT_UNKNOWN;
320 /* Note: entry->prev_cookie contains the cookie for
321 * retrieving the current dirent on the server */
322 fileid = nfs_fileid_to_ino_t(entry->ino);
323
324 /* Get a dentry if we have one */
325 if (dentry != NULL)
326 dput(dentry);
327 dentry = nfs_readdir_lookup(desc);
328
329 /* Use readdirplus info */
330 if (dentry != NULL && dentry->d_inode != NULL) {
331 d_type = dt_type(dentry->d_inode);
332 fileid = dentry->d_inode->i_ino;
333 }
334
335 res = filldir(dirent, entry->name, entry->len,
336 entry->prev_cookie, fileid, d_type);
337 if (res < 0)
338 break;
339 file->f_pos = desc->target = entry->cookie;
340 if (dir_decode(desc) != 0) {
341 desc->page_index ++;
342 break;
343 }
344 if (loop_count++ > 200) {
345 loop_count = 0;
346 schedule();
347 }
348 }
349 dir_page_release(desc);
350 if (dentry != NULL)
351 dput(dentry);
352 dfprintk(VFS, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (long long)desc->target, res);
353 return res;
354}
355
356/*
357 * If we cannot find a cookie in our cache, we suspect that this is
358 * because it points to a deleted file, so we ask the server to return
359 * whatever it thinks is the next entry. We then feed this to filldir.
360 * If all goes well, we should then be able to find our way round the
361 * cache on the next call to readdir_search_pagecache();
362 *
363 * NOTE: we cannot add the anonymous page to the pagecache because
364 * the data it contains might not be page aligned. Besides,
365 * we should already have a complete representation of the
366 * directory in the page cache by the time we get here.
367 */
368static inline
369int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
370 filldir_t filldir)
371{
372 struct file *file = desc->file;
373 struct inode *inode = file->f_dentry->d_inode;
374 struct rpc_cred *cred = nfs_file_cred(file);
375 struct page *page = NULL;
376 int status;
377
378 dfprintk(VFS, "NFS: uncached_readdir() searching for cookie %Lu\n", (long long)desc->target);
379
380 page = alloc_page(GFP_HIGHUSER);
381 if (!page) {
382 status = -ENOMEM;
383 goto out;
384 }
385 desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->target,
386 page,
387 NFS_SERVER(inode)->dtsize,
388 desc->plus);
389 NFS_FLAGS(inode) |= NFS_INO_INVALID_ATIME;
390 desc->page = page;
391 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
392 if (desc->error >= 0) {
393 if ((status = dir_decode(desc)) == 0)
394 desc->entry->prev_cookie = desc->target;
395 } else
396 status = -EIO;
397 if (status < 0)
398 goto out_release;
399
400 status = nfs_do_filldir(desc, dirent, filldir);
401
402 /* Reset read descriptor so it searches the page cache from
403 * the start upon the next call to readdir_search_pagecache() */
404 desc->page_index = 0;
405 desc->entry->cookie = desc->entry->prev_cookie = 0;
406 desc->entry->eof = 0;
407 out:
408 dfprintk(VFS, "NFS: uncached_readdir() returns %d\n", status);
409 return status;
410 out_release:
411 dir_page_release(desc);
412 goto out;
413}
414
415/* The file offset position is now represented as a true offset into the
416 * page cache as is the case in most of the other filesystems.
417 */
418static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
419{
420 struct dentry *dentry = filp->f_dentry;
421 struct inode *inode = dentry->d_inode;
422 nfs_readdir_descriptor_t my_desc,
423 *desc = &my_desc;
424 struct nfs_entry my_entry;
425 struct nfs_fh fh;
426 struct nfs_fattr fattr;
427 long res;
428
429 lock_kernel();
430
431 res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
432 if (res < 0) {
433 unlock_kernel();
434 return res;
435 }
436
437 /*
438 * filp->f_pos points to the file offset in the page cache.
439 * but if the cache has meanwhile been zapped, we need to
440 * read from the last dirent to revalidate f_pos
441 * itself.
442 */
443 memset(desc, 0, sizeof(*desc));
444
445 desc->file = filp;
446 desc->target = filp->f_pos;
447 desc->decode = NFS_PROTO(inode)->decode_dirent;
448 desc->plus = NFS_USE_READDIRPLUS(inode);
449
450 my_entry.cookie = my_entry.prev_cookie = 0;
451 my_entry.eof = 0;
452 my_entry.fh = &fh;
453 my_entry.fattr = &fattr;
454 desc->entry = &my_entry;
455
456 while(!desc->entry->eof) {
457 res = readdir_search_pagecache(desc);
458 if (res == -EBADCOOKIE) {
459 /* This means either end of directory */
460 if (desc->entry->cookie != desc->target) {
461 /* Or that the server has 'lost' a cookie */
462 res = uncached_readdir(desc, dirent, filldir);
463 if (res >= 0)
464 continue;
465 }
466 res = 0;
467 break;
468 }
469 if (res == -ETOOSMALL && desc->plus) {
470 NFS_FLAGS(inode) &= ~NFS_INO_ADVISE_RDPLUS;
471 nfs_zap_caches(inode);
472 desc->plus = 0;
473 desc->entry->eof = 0;
474 continue;
475 }
476 if (res < 0)
477 break;
478
479 res = nfs_do_filldir(desc, dirent, filldir);
480 if (res < 0) {
481 res = 0;
482 break;
483 }
484 }
485 unlock_kernel();
486 if (desc->error < 0)
487 return desc->error;
488 if (res < 0)
489 return res;
490 return 0;
491}
492
493/*
494 * All directory operations under NFS are synchronous, so fsync()
495 * is a dummy operation.
496 */
497int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync)
498{
499 return 0;
500}
501
502/*
503 * A check for whether or not the parent directory has changed.
504 * In the case it has, we assume that the dentries are untrustworthy
505 * and may need to be looked up again.
506 */
507static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry)
508{
509 if (IS_ROOT(dentry))
510 return 1;
511 if ((NFS_FLAGS(dir) & NFS_INO_INVALID_ATTR) != 0
512 || nfs_attribute_timeout(dir))
513 return 0;
514 return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata);
515}
516
517static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
518{
519 dentry->d_fsdata = (void *)verf;
520}
521
522/*
523 * Whenever an NFS operation succeeds, we know that the dentry
524 * is valid, so we update the revalidation timestamp.
525 */
526static inline void nfs_renew_times(struct dentry * dentry)
527{
528 dentry->d_time = jiffies;
529}
530
531static inline
532int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
533{
534 struct nfs_server *server = NFS_SERVER(inode);
535
536 if (nd != NULL) {
537 int ndflags = nd->flags;
538 /* VFS wants an on-the-wire revalidation */
539 if (ndflags & LOOKUP_REVAL)
540 goto out_force;
541 /* This is an open(2) */
542 if ((ndflags & LOOKUP_OPEN) &&
543 !(ndflags & LOOKUP_CONTINUE) &&
544 !(server->flags & NFS_MOUNT_NOCTO))
545 goto out_force;
546 }
547 return nfs_revalidate_inode(server, inode);
548out_force:
549 return __nfs_revalidate_inode(server, inode);
550}
551
552/*
553 * We judge how long we want to trust negative
554 * dentries by looking at the parent inode mtime.
555 *
556 * If parent mtime has changed, we revalidate, else we wait for a
557 * period corresponding to the parent's attribute cache timeout value.
558 */
559static inline
560int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
561 struct nameidata *nd)
562{
563 int ndflags = 0;
564
565 if (nd)
566 ndflags = nd->flags;
567 /* Don't revalidate a negative dentry if we're creating a new file */
568 if ((ndflags & LOOKUP_CREATE) && !(ndflags & LOOKUP_CONTINUE))
569 return 0;
570 return !nfs_check_verifier(dir, dentry);
571}
572
573/*
574 * This is called every time the dcache has a lookup hit,
575 * and we should check whether we can really trust that
576 * lookup.
577 *
578 * NOTE! The hit can be a negative hit too, don't assume
579 * we have an inode!
580 *
581 * If the parent directory is seen to have changed, we throw out the
582 * cached dentry and do a new lookup.
583 */
584static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd)
585{
586 struct inode *dir;
587 struct inode *inode;
588 struct dentry *parent;
589 int error;
590 struct nfs_fh fhandle;
591 struct nfs_fattr fattr;
592 unsigned long verifier;
593
594 parent = dget_parent(dentry);
595 lock_kernel();
596 dir = parent->d_inode;
597 inode = dentry->d_inode;
598
599 if (!inode) {
600 if (nfs_neg_need_reval(dir, dentry, nd))
601 goto out_bad;
602 goto out_valid;
603 }
604
605 if (is_bad_inode(inode)) {
606 dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n",
607 dentry->d_parent->d_name.name, dentry->d_name.name);
608 goto out_bad;
609 }
610
611 /* Revalidate parent directory attribute cache */
612 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
613 goto out_zap_parent;
614
615 /* Force a full look up iff the parent directory has changed */
616 if (nfs_check_verifier(dir, dentry)) {
617 if (nfs_lookup_verify_inode(inode, nd))
618 goto out_zap_parent;
619 goto out_valid;
620 }
621
622 if (NFS_STALE(inode))
623 goto out_bad;
624
625 verifier = nfs_save_change_attribute(dir);
626 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
627 if (error)
628 goto out_bad;
629 if (nfs_compare_fh(NFS_FH(inode), &fhandle))
630 goto out_bad;
631 if ((error = nfs_refresh_inode(inode, &fattr)) != 0)
632 goto out_bad;
633
634 nfs_renew_times(dentry);
635 nfs_set_verifier(dentry, verifier);
636 out_valid:
637 unlock_kernel();
638 dput(parent);
639 return 1;
640out_zap_parent:
641 nfs_zap_caches(dir);
642 out_bad:
643 NFS_CACHEINV(dir);
644 if (inode && S_ISDIR(inode->i_mode)) {
645 /* Purge readdir caches. */
646 nfs_zap_caches(inode);
647 /* If we have submounts, don't unhash ! */
648 if (have_submounts(dentry))
649 goto out_valid;
650 shrink_dcache_parent(dentry);
651 }
652 d_drop(dentry);
653 unlock_kernel();
654 dput(parent);
655 return 0;
656}
657
658/*
659 * This is called from dput() when d_count is going to 0.
660 */
661static int nfs_dentry_delete(struct dentry *dentry)
662{
663 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n",
664 dentry->d_parent->d_name.name, dentry->d_name.name,
665 dentry->d_flags);
666
667 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
668 /* Unhash it, so that ->d_iput() would be called */
669 return 1;
670 }
671 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) {
672 /* Unhash it, so that ancestors of killed async unlink
673 * files will be cleaned up during umount */
674 return 1;
675 }
676 return 0;
677
678}
679
680/*
681 * Called when the dentry loses inode.
682 * We use it to clean up silly-renamed files.
683 */
684static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
685{
686 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
687 lock_kernel();
688 inode->i_nlink--;
689 nfs_complete_unlink(dentry);
690 unlock_kernel();
691 }
692 /* When creating a negative dentry, we want to renew d_time */
693 nfs_renew_times(dentry);
694 iput(inode);
695}
696
697struct dentry_operations nfs_dentry_operations = {
698 .d_revalidate = nfs_lookup_revalidate,
699 .d_delete = nfs_dentry_delete,
700 .d_iput = nfs_dentry_iput,
701};
702
703static inline
704int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
705{
706 if (NFS_PROTO(dir)->version == 2)
707 return 0;
708 if (!nd || (nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_CREATE))
709 return 0;
710 return (nd->intent.open.flags & O_EXCL) != 0;
711}
712
713static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
714{
715 struct dentry *res;
716 struct inode *inode = NULL;
717 int error;
718 struct nfs_fh fhandle;
719 struct nfs_fattr fattr;
720
721 dfprintk(VFS, "NFS: lookup(%s/%s)\n",
722 dentry->d_parent->d_name.name, dentry->d_name.name);
723
724 res = ERR_PTR(-ENAMETOOLONG);
725 if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
726 goto out;
727
728 res = ERR_PTR(-ENOMEM);
729 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
730
731 lock_kernel();
732 /* Revalidate parent directory attribute cache */
733 error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
734 if (error < 0) {
735 res = ERR_PTR(error);
736 goto out_unlock;
737 }
738
739 /* If we're doing an exclusive create, optimize away the lookup */
740 if (nfs_is_exclusive_create(dir, nd))
741 goto no_entry;
742
743 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
744 if (error == -ENOENT)
745 goto no_entry;
746 if (error < 0) {
747 res = ERR_PTR(error);
748 goto out_unlock;
749 }
750 res = ERR_PTR(-EACCES);
751 inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr);
752 if (!inode)
753 goto out_unlock;
754no_entry:
755 res = d_add_unique(dentry, inode);
756 if (res != NULL)
757 dentry = res;
758 nfs_renew_times(dentry);
759 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
760out_unlock:
761 unlock_kernel();
762out:
763 return res;
764}
765
766#ifdef CONFIG_NFS_V4
767static int nfs_open_revalidate(struct dentry *, struct nameidata *);
768
769struct dentry_operations nfs4_dentry_operations = {
770 .d_revalidate = nfs_open_revalidate,
771 .d_delete = nfs_dentry_delete,
772 .d_iput = nfs_dentry_iput,
773};
774
775static int is_atomic_open(struct inode *dir, struct nameidata *nd)
776{
777 if (!nd)
778 return 0;
779 /* Check that we are indeed trying to open this file */
780 if ((nd->flags & LOOKUP_CONTINUE) || !(nd->flags & LOOKUP_OPEN))
781 return 0;
782 /* NFS does not (yet) have a stateful open for directories */
783 if (nd->flags & LOOKUP_DIRECTORY)
784 return 0;
785 /* Are we trying to write to a read only partition? */
786 if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE)))
787 return 0;
788 return 1;
789}
790
791static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
792{
793 struct dentry *res = NULL;
794 struct inode *inode = NULL;
795 int error;
796
797 /* Check that we are indeed trying to open this file */
798 if (!is_atomic_open(dir, nd))
799 goto no_open;
800
801 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) {
802 res = ERR_PTR(-ENAMETOOLONG);
803 goto out;
804 }
805 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
806
807 /* Let vfs_create() deal with O_EXCL */
808 if (nd->intent.open.flags & O_EXCL)
809 goto no_entry;
810
811 /* Open the file on the server */
812 lock_kernel();
813 /* Revalidate parent directory attribute cache */
814 error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
815 if (error < 0) {
816 res = ERR_PTR(error);
817 goto out;
818 }
819
820 if (nd->intent.open.flags & O_CREAT) {
821 nfs_begin_data_update(dir);
822 inode = nfs4_atomic_open(dir, dentry, nd);
823 nfs_end_data_update(dir);
824 } else
825 inode = nfs4_atomic_open(dir, dentry, nd);
826 unlock_kernel();
827 if (IS_ERR(inode)) {
828 error = PTR_ERR(inode);
829 switch (error) {
830 /* Make a negative dentry */
831 case -ENOENT:
832 inode = NULL;
833 break;
834 /* This turned out not to be a regular file */
835 case -ELOOP:
836 if (!(nd->intent.open.flags & O_NOFOLLOW))
837 goto no_open;
838 /* case -EISDIR: */
839 /* case -EINVAL: */
840 default:
841 res = ERR_PTR(error);
842 goto out;
843 }
844 }
845no_entry:
846 res = d_add_unique(dentry, inode);
847 if (res != NULL)
848 dentry = res;
849 nfs_renew_times(dentry);
850 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
851out:
852 return res;
853no_open:
854 return nfs_lookup(dir, dentry, nd);
855}
856
857static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd)
858{
859 struct dentry *parent = NULL;
860 struct inode *inode = dentry->d_inode;
861 struct inode *dir;
862 unsigned long verifier;
863 int openflags, ret = 0;
864
865 parent = dget_parent(dentry);
866 dir = parent->d_inode;
867 if (!is_atomic_open(dir, nd))
868 goto no_open;
869 /* We can't create new files in nfs_open_revalidate(), so we
870 * optimize away revalidation of negative dentries.
871 */
872 if (inode == NULL)
873 goto out;
874 /* NFS only supports OPEN on regular files */
875 if (!S_ISREG(inode->i_mode))
876 goto no_open;
877 openflags = nd->intent.open.flags;
878 /* We cannot do exclusive creation on a positive dentry */
879 if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
880 goto no_open;
881 /* We can't create new files, or truncate existing ones here */
882 openflags &= ~(O_CREAT|O_TRUNC);
883
884 /*
885 * Note: we're not holding inode->i_sem and so may be racing with
886 * operations that change the directory. We therefore save the
887 * change attribute *before* we do the RPC call.
888 */
889 lock_kernel();
890 verifier = nfs_save_change_attribute(dir);
891 ret = nfs4_open_revalidate(dir, dentry, openflags);
892 if (!ret)
893 nfs_set_verifier(dentry, verifier);
894 unlock_kernel();
895out:
896 dput(parent);
897 if (!ret)
898 d_drop(dentry);
899 return ret;
900no_open:
901 dput(parent);
902 if (inode != NULL && nfs_have_delegation(inode, FMODE_READ))
903 return 1;
904 return nfs_lookup_revalidate(dentry, nd);
905}
906#endif /* CONFIG_NFSV4 */
907
908static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
909{
910 struct dentry *parent = desc->file->f_dentry;
911 struct inode *dir = parent->d_inode;
912 struct nfs_entry *entry = desc->entry;
913 struct dentry *dentry, *alias;
914 struct qstr name = {
915 .name = entry->name,
916 .len = entry->len,
917 };
918 struct inode *inode;
919
920 switch (name.len) {
921 case 2:
922 if (name.name[0] == '.' && name.name[1] == '.')
923 return dget_parent(parent);
924 break;
925 case 1:
926 if (name.name[0] == '.')
927 return dget(parent);
928 }
929 name.hash = full_name_hash(name.name, name.len);
930 dentry = d_lookup(parent, &name);
931 if (dentry != NULL)
932 return dentry;
933 if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
934 return NULL;
935 /* Note: caller is already holding the dir->i_sem! */
936 dentry = d_alloc(parent, &name);
937 if (dentry == NULL)
938 return NULL;
939 dentry->d_op = NFS_PROTO(dir)->dentry_ops;
940 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
941 if (!inode) {
942 dput(dentry);
943 return NULL;
944 }
945 alias = d_add_unique(dentry, inode);
946 if (alias != NULL) {
947 dput(dentry);
948 dentry = alias;
949 }
950 nfs_renew_times(dentry);
951 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
952 return dentry;
953}
954
955/*
956 * Code common to create, mkdir, and mknod.
957 */
958int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
959 struct nfs_fattr *fattr)
960{
961 struct inode *inode;
962 int error = -EACCES;
963
964 /* We may have been initialized further down */
965 if (dentry->d_inode)
966 return 0;
967 if (fhandle->size == 0) {
968 struct inode *dir = dentry->d_parent->d_inode;
969 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr);
970 if (error)
971 goto out_err;
972 }
973 if (!(fattr->valid & NFS_ATTR_FATTR)) {
974 struct nfs_server *server = NFS_SB(dentry->d_sb);
975 error = server->rpc_ops->getattr(server, fhandle, fattr);
976 if (error < 0)
977 goto out_err;
978 }
979 error = -ENOMEM;
980 inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
981 if (inode == NULL)
982 goto out_err;
983 d_instantiate(dentry, inode);
984 return 0;
985out_err:
986 d_drop(dentry);
987 return error;
988}
989
990/*
991 * Following a failed create operation, we drop the dentry rather
992 * than retain a negative dentry. This avoids a problem in the event
993 * that the operation succeeded on the server, but an error in the
994 * reply path made it appear to have failed.
995 */
996static int nfs_create(struct inode *dir, struct dentry *dentry, int mode,
997 struct nameidata *nd)
998{
999 struct iattr attr;
1000 int error;
1001 int open_flags = 0;
1002
1003 dfprintk(VFS, "NFS: create(%s/%ld, %s\n", dir->i_sb->s_id,
1004 dir->i_ino, dentry->d_name.name);
1005
1006 attr.ia_mode = mode;
1007 attr.ia_valid = ATTR_MODE;
1008
1009 if (nd && (nd->flags & LOOKUP_CREATE))
1010 open_flags = nd->intent.open.flags;
1011
1012 lock_kernel();
1013 nfs_begin_data_update(dir);
1014 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
1015 nfs_end_data_update(dir);
1016 if (error != 0)
1017 goto out_err;
1018 nfs_renew_times(dentry);
1019 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1020 unlock_kernel();
1021 return 0;
1022out_err:
1023 unlock_kernel();
1024 d_drop(dentry);
1025 return error;
1026}
1027
1028/*
1029 * See comments for nfs_proc_create regarding failed operations.
1030 */
1031static int
1032nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1033{
1034 struct iattr attr;
1035 int status;
1036
1037 dfprintk(VFS, "NFS: mknod(%s/%ld, %s\n", dir->i_sb->s_id,
1038 dir->i_ino, dentry->d_name.name);
1039
1040 if (!new_valid_dev(rdev))
1041 return -EINVAL;
1042
1043 attr.ia_mode = mode;
1044 attr.ia_valid = ATTR_MODE;
1045
1046 lock_kernel();
1047 nfs_begin_data_update(dir);
1048 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
1049 nfs_end_data_update(dir);
1050 if (status != 0)
1051 goto out_err;
1052 nfs_renew_times(dentry);
1053 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1054 unlock_kernel();
1055 return 0;
1056out_err:
1057 unlock_kernel();
1058 d_drop(dentry);
1059 return status;
1060}
1061
1062/*
1063 * See comments for nfs_proc_create regarding failed operations.
1064 */
1065static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1066{
1067 struct iattr attr;
1068 int error;
1069
1070 dfprintk(VFS, "NFS: mkdir(%s/%ld, %s\n", dir->i_sb->s_id,
1071 dir->i_ino, dentry->d_name.name);
1072
1073 attr.ia_valid = ATTR_MODE;
1074 attr.ia_mode = mode | S_IFDIR;
1075
1076 lock_kernel();
1077 nfs_begin_data_update(dir);
1078 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
1079 nfs_end_data_update(dir);
1080 if (error != 0)
1081 goto out_err;
1082 nfs_renew_times(dentry);
1083 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1084 unlock_kernel();
1085 return 0;
1086out_err:
1087 d_drop(dentry);
1088 unlock_kernel();
1089 return error;
1090}
1091
1092static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
1093{
1094 int error;
1095
1096 dfprintk(VFS, "NFS: rmdir(%s/%ld, %s\n", dir->i_sb->s_id,
1097 dir->i_ino, dentry->d_name.name);
1098
1099 lock_kernel();
1100 nfs_begin_data_update(dir);
1101 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
1102 /* Ensure the VFS deletes this inode */
1103 if (error == 0 && dentry->d_inode != NULL)
1104 dentry->d_inode->i_nlink = 0;
1105 nfs_end_data_update(dir);
1106 unlock_kernel();
1107
1108 return error;
1109}
1110
1111static int nfs_sillyrename(struct inode *dir, struct dentry *dentry)
1112{
1113 static unsigned int sillycounter;
1114 const int i_inosize = sizeof(dir->i_ino)*2;
1115 const int countersize = sizeof(sillycounter)*2;
1116 const int slen = sizeof(".nfs") + i_inosize + countersize - 1;
1117 char silly[slen+1];
1118 struct qstr qsilly;
1119 struct dentry *sdentry;
1120 int error = -EIO;
1121
1122 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
1123 dentry->d_parent->d_name.name, dentry->d_name.name,
1124 atomic_read(&dentry->d_count));
1125
1126#ifdef NFS_PARANOIA
1127if (!dentry->d_inode)
1128printk("NFS: silly-renaming %s/%s, negative dentry??\n",
1129dentry->d_parent->d_name.name, dentry->d_name.name);
1130#endif
1131 /*
1132 * We don't allow a dentry to be silly-renamed twice.
1133 */
1134 error = -EBUSY;
1135 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
1136 goto out;
1137
1138 sprintf(silly, ".nfs%*.*lx",
1139 i_inosize, i_inosize, dentry->d_inode->i_ino);
1140
1141 sdentry = NULL;
1142 do {
1143 char *suffix = silly + slen - countersize;
1144
1145 dput(sdentry);
1146 sillycounter++;
1147 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
1148
1149 dfprintk(VFS, "trying to rename %s to %s\n",
1150 dentry->d_name.name, silly);
1151
1152 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
1153 /*
1154 * N.B. Better to return EBUSY here ... it could be
1155 * dangerous to delete the file while it's in use.
1156 */
1157 if (IS_ERR(sdentry))
1158 goto out;
1159 } while(sdentry->d_inode != NULL); /* need negative lookup */
1160
1161 qsilly.name = silly;
1162 qsilly.len = strlen(silly);
1163 nfs_begin_data_update(dir);
1164 if (dentry->d_inode) {
1165 nfs_begin_data_update(dentry->d_inode);
1166 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
1167 dir, &qsilly);
1168 nfs_end_data_update(dentry->d_inode);
1169 } else
1170 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name,
1171 dir, &qsilly);
1172 nfs_end_data_update(dir);
1173 if (!error) {
1174 nfs_renew_times(dentry);
1175 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1176 d_move(dentry, sdentry);
1177 error = nfs_async_unlink(dentry);
1178 /* If we return 0 we don't unlink */
1179 }
1180 dput(sdentry);
1181out:
1182 return error;
1183}
1184
1185/*
1186 * Remove a file after making sure there are no pending writes,
1187 * and after checking that the file has only one user.
1188 *
1189 * We invalidate the attribute cache and free the inode prior to the operation
1190 * to avoid possible races if the server reuses the inode.
1191 */
1192static int nfs_safe_remove(struct dentry *dentry)
1193{
1194 struct inode *dir = dentry->d_parent->d_inode;
1195 struct inode *inode = dentry->d_inode;
1196 int error = -EBUSY;
1197
1198 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n",
1199 dentry->d_parent->d_name.name, dentry->d_name.name);
1200
1201 /* If the dentry was sillyrenamed, we simply call d_delete() */
1202 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1203 error = 0;
1204 goto out;
1205 }
1206
1207 nfs_begin_data_update(dir);
1208 if (inode != NULL) {
1209 nfs_begin_data_update(inode);
1210 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
1211 /* The VFS may want to delete this inode */
1212 if (error == 0)
1213 inode->i_nlink--;
1214 nfs_end_data_update(inode);
1215 } else
1216 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name);
1217 nfs_end_data_update(dir);
1218out:
1219 return error;
1220}
1221
1222/* We do silly rename. In case sillyrename() returns -EBUSY, the inode
1223 * belongs to an active ".nfs..." file and we return -EBUSY.
1224 *
1225 * If sillyrename() returns 0, we do nothing, otherwise we unlink.
1226 */
1227static int nfs_unlink(struct inode *dir, struct dentry *dentry)
1228{
1229 int error;
1230 int need_rehash = 0;
1231
1232 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id,
1233 dir->i_ino, dentry->d_name.name);
1234
1235 lock_kernel();
1236 spin_lock(&dcache_lock);
1237 spin_lock(&dentry->d_lock);
1238 if (atomic_read(&dentry->d_count) > 1) {
1239 spin_unlock(&dentry->d_lock);
1240 spin_unlock(&dcache_lock);
1241 error = nfs_sillyrename(dir, dentry);
1242 unlock_kernel();
1243 return error;
1244 }
1245 if (!d_unhashed(dentry)) {
1246 __d_drop(dentry);
1247 need_rehash = 1;
1248 }
1249 spin_unlock(&dentry->d_lock);
1250 spin_unlock(&dcache_lock);
1251 error = nfs_safe_remove(dentry);
1252 if (!error) {
1253 nfs_renew_times(dentry);
1254 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1255 } else if (need_rehash)
1256 d_rehash(dentry);
1257 unlock_kernel();
1258 return error;
1259}
1260
1261static int
1262nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1263{
1264 struct iattr attr;
1265 struct nfs_fattr sym_attr;
1266 struct nfs_fh sym_fh;
1267 struct qstr qsymname;
1268 int error;
1269
1270 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
1271 dir->i_ino, dentry->d_name.name, symname);
1272
1273#ifdef NFS_PARANOIA
1274if (dentry->d_inode)
1275printk("nfs_proc_symlink: %s/%s not negative!\n",
1276dentry->d_parent->d_name.name, dentry->d_name.name);
1277#endif
1278 /*
1279 * Fill in the sattr for the call.
1280 * Note: SunOS 4.1.2 crashes if the mode isn't initialized!
1281 */
1282 attr.ia_valid = ATTR_MODE;
1283 attr.ia_mode = S_IFLNK | S_IRWXUGO;
1284
1285 qsymname.name = symname;
1286 qsymname.len = strlen(symname);
1287
1288 lock_kernel();
1289 nfs_begin_data_update(dir);
1290 error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname,
1291 &attr, &sym_fh, &sym_attr);
1292 nfs_end_data_update(dir);
1293 if (!error) {
1294 error = nfs_instantiate(dentry, &sym_fh, &sym_attr);
1295 } else {
1296 if (error == -EEXIST)
1297 printk("nfs_proc_symlink: %s/%s already exists??\n",
1298 dentry->d_parent->d_name.name, dentry->d_name.name);
1299 d_drop(dentry);
1300 }
1301 unlock_kernel();
1302 return error;
1303}
1304
1305static int
1306nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1307{
1308 struct inode *inode = old_dentry->d_inode;
1309 int error;
1310
1311 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n",
1312 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
1313 dentry->d_parent->d_name.name, dentry->d_name.name);
1314
1315 /*
1316 * Drop the dentry in advance to force a new lookup.
1317 * Since nfs_proc_link doesn't return a file handle,
1318 * we can't use the existing dentry.
1319 */
1320 lock_kernel();
1321 d_drop(dentry);
1322
1323 nfs_begin_data_update(dir);
1324 nfs_begin_data_update(inode);
1325 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
1326 nfs_end_data_update(inode);
1327 nfs_end_data_update(dir);
1328 unlock_kernel();
1329 return error;
1330}
1331
1332/*
1333 * RENAME
1334 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
1335 * different file handle for the same inode after a rename (e.g. when
1336 * moving to a different directory). A fail-safe method to do so would
1337 * be to look up old_dir/old_name, create a link to new_dir/new_name and
1338 * rename the old file using the sillyrename stuff. This way, the original
1339 * file in old_dir will go away when the last process iput()s the inode.
1340 *
1341 * FIXED.
1342 *
1343 * It actually works quite well. One needs to have the possibility for
1344 * at least one ".nfs..." file in each directory the file ever gets
1345 * moved or linked to which happens automagically with the new
1346 * implementation that only depends on the dcache stuff instead of
1347 * using the inode layer
1348 *
1349 * Unfortunately, things are a little more complicated than indicated
1350 * above. For a cross-directory move, we want to make sure we can get
1351 * rid of the old inode after the operation. This means there must be
1352 * no pending writes (if it's a file), and the use count must be 1.
1353 * If these conditions are met, we can drop the dentries before doing
1354 * the rename.
1355 */
1356static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
1357 struct inode *new_dir, struct dentry *new_dentry)
1358{
1359 struct inode *old_inode = old_dentry->d_inode;
1360 struct inode *new_inode = new_dentry->d_inode;
1361 struct dentry *dentry = NULL, *rehash = NULL;
1362 int error = -EBUSY;
1363
1364 /*
1365 * To prevent any new references to the target during the rename,
1366 * we unhash the dentry and free the inode in advance.
1367 */
1368 lock_kernel();
1369 if (!d_unhashed(new_dentry)) {
1370 d_drop(new_dentry);
1371 rehash = new_dentry;
1372 }
1373
1374 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n",
1375 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
1376 new_dentry->d_parent->d_name.name, new_dentry->d_name.name,
1377 atomic_read(&new_dentry->d_count));
1378
1379 /*
1380 * First check whether the target is busy ... we can't
1381 * safely do _any_ rename if the target is in use.
1382 *
1383 * For files, make a copy of the dentry and then do a
1384 * silly-rename. If the silly-rename succeeds, the
1385 * copied dentry is hashed and becomes the new target.
1386 */
1387 if (!new_inode)
1388 goto go_ahead;
1389 if (S_ISDIR(new_inode->i_mode))
1390 goto out;
1391 else if (atomic_read(&new_dentry->d_count) > 2) {
1392 int err;
1393 /* copy the target dentry's name */
1394 dentry = d_alloc(new_dentry->d_parent,
1395 &new_dentry->d_name);
1396 if (!dentry)
1397 goto out;
1398
1399 /* silly-rename the existing target ... */
1400 err = nfs_sillyrename(new_dir, new_dentry);
1401 if (!err) {
1402 new_dentry = rehash = dentry;
1403 new_inode = NULL;
1404 /* instantiate the replacement target */
1405 d_instantiate(new_dentry, NULL);
1406 } else if (atomic_read(&new_dentry->d_count) > 1) {
1407 /* dentry still busy? */
1408#ifdef NFS_PARANOIA
1409 printk("nfs_rename: target %s/%s busy, d_count=%d\n",
1410 new_dentry->d_parent->d_name.name,
1411 new_dentry->d_name.name,
1412 atomic_read(&new_dentry->d_count));
1413#endif
1414 goto out;
1415 }
1416 }
1417
1418go_ahead:
1419 /*
1420 * ... prune child dentries and writebacks if needed.
1421 */
1422 if (atomic_read(&old_dentry->d_count) > 1) {
1423 nfs_wb_all(old_inode);
1424 shrink_dcache_parent(old_dentry);
1425 }
1426
1427 if (new_inode)
1428 d_delete(new_dentry);
1429
1430 nfs_begin_data_update(old_dir);
1431 nfs_begin_data_update(new_dir);
1432 nfs_begin_data_update(old_inode);
1433 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name,
1434 new_dir, &new_dentry->d_name);
1435 nfs_end_data_update(old_inode);
1436 nfs_end_data_update(new_dir);
1437 nfs_end_data_update(old_dir);
1438out:
1439 if (rehash)
1440 d_rehash(rehash);
1441 if (!error) {
1442 if (!S_ISDIR(old_inode->i_mode))
1443 d_move(old_dentry, new_dentry);
1444 nfs_renew_times(new_dentry);
1445 nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
1446 }
1447
1448 /* new dentry created? */
1449 if (dentry)
1450 dput(dentry);
1451 unlock_kernel();
1452 return error;
1453}
1454
1455int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
1456{
1457 struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
1458
1459 if (cache->cred != cred
1460 || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
1461 || (NFS_FLAGS(inode) & NFS_INO_INVALID_ACCESS))
1462 return -ENOENT;
1463 memcpy(res, cache, sizeof(*res));
1464 return 0;
1465}
1466
1467void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
1468{
1469 struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
1470
1471 if (cache->cred != set->cred) {
1472 if (cache->cred)
1473 put_rpccred(cache->cred);
1474 cache->cred = get_rpccred(set->cred);
1475 }
1476 NFS_FLAGS(inode) &= ~NFS_INO_INVALID_ACCESS;
1477 cache->jiffies = set->jiffies;
1478 cache->mask = set->mask;
1479}
1480
1481static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
1482{
1483 struct nfs_access_entry cache;
1484 int status;
1485
1486 status = nfs_access_get_cached(inode, cred, &cache);
1487 if (status == 0)
1488 goto out;
1489
1490 /* Be clever: ask server to check for all possible rights */
1491 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
1492 cache.cred = cred;
1493 cache.jiffies = jiffies;
1494 status = NFS_PROTO(inode)->access(inode, &cache);
1495 if (status != 0)
1496 return status;
1497 nfs_access_add_cache(inode, &cache);
1498out:
1499 if ((cache.mask & mask) == mask)
1500 return 0;
1501 return -EACCES;
1502}
1503
1504int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
1505{
1506 struct rpc_cred *cred;
1507 int res = 0;
1508
1509 if (mask == 0)
1510 goto out;
1511 /* Is this sys_access() ? */
1512 if (nd != NULL && (nd->flags & LOOKUP_ACCESS))
1513 goto force_lookup;
1514
1515 switch (inode->i_mode & S_IFMT) {
1516 case S_IFLNK:
1517 goto out;
1518 case S_IFREG:
1519 /* NFSv4 has atomic_open... */
1520 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)
1521 && nd != NULL
1522 && (nd->flags & LOOKUP_OPEN))
1523 goto out;
1524 break;
1525 case S_IFDIR:
1526 /*
1527 * Optimize away all write operations, since the server
1528 * will check permissions when we perform the op.
1529 */
1530 if ((mask & MAY_WRITE) && !(mask & MAY_READ))
1531 goto out;
1532 }
1533
1534force_lookup:
1535 lock_kernel();
1536
1537 if (!NFS_PROTO(inode)->access)
1538 goto out_notsup;
1539
1540 cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
1541 if (!IS_ERR(cred)) {
1542 res = nfs_do_access(inode, cred, mask);
1543 put_rpccred(cred);
1544 } else
1545 res = PTR_ERR(cred);
1546 unlock_kernel();
1547out:
1548 return res;
1549out_notsup:
1550 res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
1551 if (res == 0)
1552 res = generic_permission(inode, mask, NULL);
1553 unlock_kernel();
1554 return res;
1555}
1556
1557/*
1558 * Local variables:
1559 * version-control: t
1560 * kept-new-versions: 5
1561 * End:
1562 */
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-08 03:57:29 -0500