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Commit | Line | Data |
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1da177e4 LT |
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 | ||
40 | static int nfs_opendir(struct inode *, struct file *); | |
41 | static int nfs_readdir(struct file *, void *, filldir_t); | |
42 | static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); | |
43 | static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *); | |
44 | static int nfs_mkdir(struct inode *, struct dentry *, int); | |
45 | static int nfs_rmdir(struct inode *, struct dentry *); | |
46 | static int nfs_unlink(struct inode *, struct dentry *); | |
47 | static int nfs_symlink(struct inode *, struct dentry *, const char *); | |
48 | static int nfs_link(struct dentry *, struct inode *, struct dentry *); | |
49 | static int nfs_mknod(struct inode *, struct dentry *, int, dev_t); | |
50 | static int nfs_rename(struct inode *, struct dentry *, | |
51 | struct inode *, struct dentry *); | |
52 | static int nfs_fsync_dir(struct file *, struct dentry *, int); | |
53 | ||
54 | struct 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 | ||
62 | struct 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 | ||
79 | static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *); | |
80 | struct 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 | */ | |
100 | static int | |
101 | nfs_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 | ||
113 | typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int); | |
114 | typedef 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 | */ | |
138 | static | |
139 | int 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 | ||
183 | static inline | |
184 | int 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 | ||
194 | static inline | |
195 | void 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 | */ | |
211 | static inline | |
212 | int 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 | */ | |
235 | static inline | |
236 | int 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 | */ | |
273 | static inline | |
274 | int 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 | ||
295 | static inline unsigned int dt_type(struct inode *inode) | |
296 | { | |
297 | return (inode->i_mode >> 12) & 15; | |
298 | } | |
299 | ||
300 | static 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 | */ | |
305 | static | |
306 | int 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 | */ | |
368 | static inline | |
369 | int 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 | */ | |
418 | static 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 | */ | |
497 | int 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 | */ | |
507 | static 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 | ||
517 | static 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 | */ | |
526 | static inline void nfs_renew_times(struct dentry * dentry) | |
527 | { | |
528 | dentry->d_time = jiffies; | |
529 | } | |
530 | ||
1d6757fb TM |
531 | /* |
532 | * Return the intent data that applies to this particular path component | |
533 | * | |
534 | * Note that the current set of intents only apply to the very last | |
535 | * component of the path. | |
536 | * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT. | |
537 | */ | |
538 | static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask) | |
539 | { | |
540 | if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT)) | |
541 | return 0; | |
542 | return nd->flags & mask; | |
543 | } | |
544 | ||
545 | /* | |
546 | * Inode and filehandle revalidation for lookups. | |
547 | * | |
548 | * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, | |
549 | * or if the intent information indicates that we're about to open this | |
550 | * particular file and the "nocto" mount flag is not set. | |
551 | * | |
552 | */ | |
1da177e4 LT |
553 | static inline |
554 | int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) | |
555 | { | |
556 | struct nfs_server *server = NFS_SERVER(inode); | |
557 | ||
558 | if (nd != NULL) { | |
1da177e4 | 559 | /* VFS wants an on-the-wire revalidation */ |
1d6757fb | 560 | if (nd->flags & LOOKUP_REVAL) |
1da177e4 LT |
561 | goto out_force; |
562 | /* This is an open(2) */ | |
1d6757fb | 563 | if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 && |
1da177e4 LT |
564 | !(server->flags & NFS_MOUNT_NOCTO)) |
565 | goto out_force; | |
566 | } | |
567 | return nfs_revalidate_inode(server, inode); | |
568 | out_force: | |
569 | return __nfs_revalidate_inode(server, inode); | |
570 | } | |
571 | ||
572 | /* | |
573 | * We judge how long we want to trust negative | |
574 | * dentries by looking at the parent inode mtime. | |
575 | * | |
576 | * If parent mtime has changed, we revalidate, else we wait for a | |
577 | * period corresponding to the parent's attribute cache timeout value. | |
578 | */ | |
579 | static inline | |
580 | int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, | |
581 | struct nameidata *nd) | |
582 | { | |
1da177e4 | 583 | /* Don't revalidate a negative dentry if we're creating a new file */ |
1d6757fb | 584 | if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0) |
1da177e4 LT |
585 | return 0; |
586 | return !nfs_check_verifier(dir, dentry); | |
587 | } | |
588 | ||
589 | /* | |
590 | * This is called every time the dcache has a lookup hit, | |
591 | * and we should check whether we can really trust that | |
592 | * lookup. | |
593 | * | |
594 | * NOTE! The hit can be a negative hit too, don't assume | |
595 | * we have an inode! | |
596 | * | |
597 | * If the parent directory is seen to have changed, we throw out the | |
598 | * cached dentry and do a new lookup. | |
599 | */ | |
600 | static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd) | |
601 | { | |
602 | struct inode *dir; | |
603 | struct inode *inode; | |
604 | struct dentry *parent; | |
605 | int error; | |
606 | struct nfs_fh fhandle; | |
607 | struct nfs_fattr fattr; | |
608 | unsigned long verifier; | |
609 | ||
610 | parent = dget_parent(dentry); | |
611 | lock_kernel(); | |
612 | dir = parent->d_inode; | |
613 | inode = dentry->d_inode; | |
614 | ||
615 | if (!inode) { | |
616 | if (nfs_neg_need_reval(dir, dentry, nd)) | |
617 | goto out_bad; | |
618 | goto out_valid; | |
619 | } | |
620 | ||
621 | if (is_bad_inode(inode)) { | |
622 | dfprintk(VFS, "nfs_lookup_validate: %s/%s has dud inode\n", | |
623 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
624 | goto out_bad; | |
625 | } | |
626 | ||
627 | /* Revalidate parent directory attribute cache */ | |
628 | if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) | |
629 | goto out_zap_parent; | |
630 | ||
631 | /* Force a full look up iff the parent directory has changed */ | |
632 | if (nfs_check_verifier(dir, dentry)) { | |
633 | if (nfs_lookup_verify_inode(inode, nd)) | |
634 | goto out_zap_parent; | |
635 | goto out_valid; | |
636 | } | |
637 | ||
638 | if (NFS_STALE(inode)) | |
639 | goto out_bad; | |
640 | ||
641 | verifier = nfs_save_change_attribute(dir); | |
642 | error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); | |
643 | if (error) | |
644 | goto out_bad; | |
645 | if (nfs_compare_fh(NFS_FH(inode), &fhandle)) | |
646 | goto out_bad; | |
647 | if ((error = nfs_refresh_inode(inode, &fattr)) != 0) | |
648 | goto out_bad; | |
649 | ||
650 | nfs_renew_times(dentry); | |
651 | nfs_set_verifier(dentry, verifier); | |
652 | out_valid: | |
653 | unlock_kernel(); | |
654 | dput(parent); | |
655 | return 1; | |
656 | out_zap_parent: | |
657 | nfs_zap_caches(dir); | |
658 | out_bad: | |
659 | NFS_CACHEINV(dir); | |
660 | if (inode && S_ISDIR(inode->i_mode)) { | |
661 | /* Purge readdir caches. */ | |
662 | nfs_zap_caches(inode); | |
663 | /* If we have submounts, don't unhash ! */ | |
664 | if (have_submounts(dentry)) | |
665 | goto out_valid; | |
666 | shrink_dcache_parent(dentry); | |
667 | } | |
668 | d_drop(dentry); | |
669 | unlock_kernel(); | |
670 | dput(parent); | |
671 | return 0; | |
672 | } | |
673 | ||
674 | /* | |
675 | * This is called from dput() when d_count is going to 0. | |
676 | */ | |
677 | static int nfs_dentry_delete(struct dentry *dentry) | |
678 | { | |
679 | dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", | |
680 | dentry->d_parent->d_name.name, dentry->d_name.name, | |
681 | dentry->d_flags); | |
682 | ||
683 | if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { | |
684 | /* Unhash it, so that ->d_iput() would be called */ | |
685 | return 1; | |
686 | } | |
687 | if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { | |
688 | /* Unhash it, so that ancestors of killed async unlink | |
689 | * files will be cleaned up during umount */ | |
690 | return 1; | |
691 | } | |
692 | return 0; | |
693 | ||
694 | } | |
695 | ||
696 | /* | |
697 | * Called when the dentry loses inode. | |
698 | * We use it to clean up silly-renamed files. | |
699 | */ | |
700 | static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) | |
701 | { | |
702 | if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { | |
703 | lock_kernel(); | |
704 | inode->i_nlink--; | |
705 | nfs_complete_unlink(dentry); | |
706 | unlock_kernel(); | |
707 | } | |
708 | /* When creating a negative dentry, we want to renew d_time */ | |
709 | nfs_renew_times(dentry); | |
710 | iput(inode); | |
711 | } | |
712 | ||
713 | struct dentry_operations nfs_dentry_operations = { | |
714 | .d_revalidate = nfs_lookup_revalidate, | |
715 | .d_delete = nfs_dentry_delete, | |
716 | .d_iput = nfs_dentry_iput, | |
717 | }; | |
718 | ||
1d6757fb TM |
719 | /* |
720 | * Use intent information to check whether or not we're going to do | |
721 | * an O_EXCL create using this path component. | |
722 | */ | |
1da177e4 LT |
723 | static inline |
724 | int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) | |
725 | { | |
726 | if (NFS_PROTO(dir)->version == 2) | |
727 | return 0; | |
1d6757fb | 728 | if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0) |
1da177e4 LT |
729 | return 0; |
730 | return (nd->intent.open.flags & O_EXCL) != 0; | |
731 | } | |
732 | ||
733 | static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) | |
734 | { | |
735 | struct dentry *res; | |
736 | struct inode *inode = NULL; | |
737 | int error; | |
738 | struct nfs_fh fhandle; | |
739 | struct nfs_fattr fattr; | |
740 | ||
741 | dfprintk(VFS, "NFS: lookup(%s/%s)\n", | |
742 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
743 | ||
744 | res = ERR_PTR(-ENAMETOOLONG); | |
745 | if (dentry->d_name.len > NFS_SERVER(dir)->namelen) | |
746 | goto out; | |
747 | ||
748 | res = ERR_PTR(-ENOMEM); | |
749 | dentry->d_op = NFS_PROTO(dir)->dentry_ops; | |
750 | ||
751 | lock_kernel(); | |
752 | /* Revalidate parent directory attribute cache */ | |
753 | error = nfs_revalidate_inode(NFS_SERVER(dir), dir); | |
754 | if (error < 0) { | |
755 | res = ERR_PTR(error); | |
756 | goto out_unlock; | |
757 | } | |
758 | ||
759 | /* If we're doing an exclusive create, optimize away the lookup */ | |
760 | if (nfs_is_exclusive_create(dir, nd)) | |
761 | goto no_entry; | |
762 | ||
763 | error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); | |
764 | if (error == -ENOENT) | |
765 | goto no_entry; | |
766 | if (error < 0) { | |
767 | res = ERR_PTR(error); | |
768 | goto out_unlock; | |
769 | } | |
770 | res = ERR_PTR(-EACCES); | |
771 | inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); | |
772 | if (!inode) | |
773 | goto out_unlock; | |
774 | no_entry: | |
775 | res = d_add_unique(dentry, inode); | |
776 | if (res != NULL) | |
777 | dentry = res; | |
778 | nfs_renew_times(dentry); | |
779 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
780 | out_unlock: | |
781 | unlock_kernel(); | |
782 | out: | |
783 | return res; | |
784 | } | |
785 | ||
786 | #ifdef CONFIG_NFS_V4 | |
787 | static int nfs_open_revalidate(struct dentry *, struct nameidata *); | |
788 | ||
789 | struct dentry_operations nfs4_dentry_operations = { | |
790 | .d_revalidate = nfs_open_revalidate, | |
791 | .d_delete = nfs_dentry_delete, | |
792 | .d_iput = nfs_dentry_iput, | |
793 | }; | |
794 | ||
1d6757fb TM |
795 | /* |
796 | * Use intent information to determine whether we need to substitute | |
797 | * the NFSv4-style stateful OPEN for the LOOKUP call | |
798 | */ | |
1da177e4 LT |
799 | static int is_atomic_open(struct inode *dir, struct nameidata *nd) |
800 | { | |
1d6757fb | 801 | if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0) |
1da177e4 LT |
802 | return 0; |
803 | /* NFS does not (yet) have a stateful open for directories */ | |
804 | if (nd->flags & LOOKUP_DIRECTORY) | |
805 | return 0; | |
806 | /* Are we trying to write to a read only partition? */ | |
807 | if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) | |
808 | return 0; | |
809 | return 1; | |
810 | } | |
811 | ||
812 | static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
813 | { | |
814 | struct dentry *res = NULL; | |
815 | struct inode *inode = NULL; | |
816 | int error; | |
817 | ||
818 | /* Check that we are indeed trying to open this file */ | |
819 | if (!is_atomic_open(dir, nd)) | |
820 | goto no_open; | |
821 | ||
822 | if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { | |
823 | res = ERR_PTR(-ENAMETOOLONG); | |
824 | goto out; | |
825 | } | |
826 | dentry->d_op = NFS_PROTO(dir)->dentry_ops; | |
827 | ||
828 | /* Let vfs_create() deal with O_EXCL */ | |
829 | if (nd->intent.open.flags & O_EXCL) | |
830 | goto no_entry; | |
831 | ||
832 | /* Open the file on the server */ | |
833 | lock_kernel(); | |
834 | /* Revalidate parent directory attribute cache */ | |
835 | error = nfs_revalidate_inode(NFS_SERVER(dir), dir); | |
836 | if (error < 0) { | |
837 | res = ERR_PTR(error); | |
838 | goto out; | |
839 | } | |
840 | ||
841 | if (nd->intent.open.flags & O_CREAT) { | |
842 | nfs_begin_data_update(dir); | |
843 | inode = nfs4_atomic_open(dir, dentry, nd); | |
844 | nfs_end_data_update(dir); | |
845 | } else | |
846 | inode = nfs4_atomic_open(dir, dentry, nd); | |
847 | unlock_kernel(); | |
848 | if (IS_ERR(inode)) { | |
849 | error = PTR_ERR(inode); | |
850 | switch (error) { | |
851 | /* Make a negative dentry */ | |
852 | case -ENOENT: | |
853 | inode = NULL; | |
854 | break; | |
855 | /* This turned out not to be a regular file */ | |
856 | case -ELOOP: | |
857 | if (!(nd->intent.open.flags & O_NOFOLLOW)) | |
858 | goto no_open; | |
859 | /* case -EISDIR: */ | |
860 | /* case -EINVAL: */ | |
861 | default: | |
862 | res = ERR_PTR(error); | |
863 | goto out; | |
864 | } | |
865 | } | |
866 | no_entry: | |
867 | res = d_add_unique(dentry, inode); | |
868 | if (res != NULL) | |
869 | dentry = res; | |
870 | nfs_renew_times(dentry); | |
871 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
872 | out: | |
873 | return res; | |
874 | no_open: | |
875 | return nfs_lookup(dir, dentry, nd); | |
876 | } | |
877 | ||
878 | static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) | |
879 | { | |
880 | struct dentry *parent = NULL; | |
881 | struct inode *inode = dentry->d_inode; | |
882 | struct inode *dir; | |
883 | unsigned long verifier; | |
884 | int openflags, ret = 0; | |
885 | ||
886 | parent = dget_parent(dentry); | |
887 | dir = parent->d_inode; | |
888 | if (!is_atomic_open(dir, nd)) | |
889 | goto no_open; | |
890 | /* We can't create new files in nfs_open_revalidate(), so we | |
891 | * optimize away revalidation of negative dentries. | |
892 | */ | |
893 | if (inode == NULL) | |
894 | goto out; | |
895 | /* NFS only supports OPEN on regular files */ | |
896 | if (!S_ISREG(inode->i_mode)) | |
897 | goto no_open; | |
898 | openflags = nd->intent.open.flags; | |
899 | /* We cannot do exclusive creation on a positive dentry */ | |
900 | if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) | |
901 | goto no_open; | |
902 | /* We can't create new files, or truncate existing ones here */ | |
903 | openflags &= ~(O_CREAT|O_TRUNC); | |
904 | ||
905 | /* | |
906 | * Note: we're not holding inode->i_sem and so may be racing with | |
907 | * operations that change the directory. We therefore save the | |
908 | * change attribute *before* we do the RPC call. | |
909 | */ | |
910 | lock_kernel(); | |
911 | verifier = nfs_save_change_attribute(dir); | |
912 | ret = nfs4_open_revalidate(dir, dentry, openflags); | |
913 | if (!ret) | |
914 | nfs_set_verifier(dentry, verifier); | |
915 | unlock_kernel(); | |
916 | out: | |
917 | dput(parent); | |
918 | if (!ret) | |
919 | d_drop(dentry); | |
920 | return ret; | |
921 | no_open: | |
922 | dput(parent); | |
923 | if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) | |
924 | return 1; | |
925 | return nfs_lookup_revalidate(dentry, nd); | |
926 | } | |
927 | #endif /* CONFIG_NFSV4 */ | |
928 | ||
929 | static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) | |
930 | { | |
931 | struct dentry *parent = desc->file->f_dentry; | |
932 | struct inode *dir = parent->d_inode; | |
933 | struct nfs_entry *entry = desc->entry; | |
934 | struct dentry *dentry, *alias; | |
935 | struct qstr name = { | |
936 | .name = entry->name, | |
937 | .len = entry->len, | |
938 | }; | |
939 | struct inode *inode; | |
940 | ||
941 | switch (name.len) { | |
942 | case 2: | |
943 | if (name.name[0] == '.' && name.name[1] == '.') | |
944 | return dget_parent(parent); | |
945 | break; | |
946 | case 1: | |
947 | if (name.name[0] == '.') | |
948 | return dget(parent); | |
949 | } | |
950 | name.hash = full_name_hash(name.name, name.len); | |
951 | dentry = d_lookup(parent, &name); | |
952 | if (dentry != NULL) | |
953 | return dentry; | |
954 | if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) | |
955 | return NULL; | |
956 | /* Note: caller is already holding the dir->i_sem! */ | |
957 | dentry = d_alloc(parent, &name); | |
958 | if (dentry == NULL) | |
959 | return NULL; | |
960 | dentry->d_op = NFS_PROTO(dir)->dentry_ops; | |
961 | inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); | |
962 | if (!inode) { | |
963 | dput(dentry); | |
964 | return NULL; | |
965 | } | |
966 | alias = d_add_unique(dentry, inode); | |
967 | if (alias != NULL) { | |
968 | dput(dentry); | |
969 | dentry = alias; | |
970 | } | |
971 | nfs_renew_times(dentry); | |
972 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
973 | return dentry; | |
974 | } | |
975 | ||
976 | /* | |
977 | * Code common to create, mkdir, and mknod. | |
978 | */ | |
979 | int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, | |
980 | struct nfs_fattr *fattr) | |
981 | { | |
982 | struct inode *inode; | |
983 | int error = -EACCES; | |
984 | ||
985 | /* We may have been initialized further down */ | |
986 | if (dentry->d_inode) | |
987 | return 0; | |
988 | if (fhandle->size == 0) { | |
989 | struct inode *dir = dentry->d_parent->d_inode; | |
990 | error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); | |
991 | if (error) | |
992 | goto out_err; | |
993 | } | |
994 | if (!(fattr->valid & NFS_ATTR_FATTR)) { | |
995 | struct nfs_server *server = NFS_SB(dentry->d_sb); | |
996 | error = server->rpc_ops->getattr(server, fhandle, fattr); | |
997 | if (error < 0) | |
998 | goto out_err; | |
999 | } | |
1000 | error = -ENOMEM; | |
1001 | inode = nfs_fhget(dentry->d_sb, fhandle, fattr); | |
1002 | if (inode == NULL) | |
1003 | goto out_err; | |
1004 | d_instantiate(dentry, inode); | |
1005 | return 0; | |
1006 | out_err: | |
1007 | d_drop(dentry); | |
1008 | return error; | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * Following a failed create operation, we drop the dentry rather | |
1013 | * than retain a negative dentry. This avoids a problem in the event | |
1014 | * that the operation succeeded on the server, but an error in the | |
1015 | * reply path made it appear to have failed. | |
1016 | */ | |
1017 | static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
1018 | struct nameidata *nd) | |
1019 | { | |
1020 | struct iattr attr; | |
1021 | int error; | |
1022 | int open_flags = 0; | |
1023 | ||
1024 | dfprintk(VFS, "NFS: create(%s/%ld, %s\n", dir->i_sb->s_id, | |
1025 | dir->i_ino, dentry->d_name.name); | |
1026 | ||
1027 | attr.ia_mode = mode; | |
1028 | attr.ia_valid = ATTR_MODE; | |
1029 | ||
1030 | if (nd && (nd->flags & LOOKUP_CREATE)) | |
1031 | open_flags = nd->intent.open.flags; | |
1032 | ||
1033 | lock_kernel(); | |
1034 | nfs_begin_data_update(dir); | |
1035 | error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); | |
1036 | nfs_end_data_update(dir); | |
1037 | if (error != 0) | |
1038 | goto out_err; | |
1039 | nfs_renew_times(dentry); | |
1040 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
1041 | unlock_kernel(); | |
1042 | return 0; | |
1043 | out_err: | |
1044 | unlock_kernel(); | |
1045 | d_drop(dentry); | |
1046 | return error; | |
1047 | } | |
1048 | ||
1049 | /* | |
1050 | * See comments for nfs_proc_create regarding failed operations. | |
1051 | */ | |
1052 | static int | |
1053 | nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev) | |
1054 | { | |
1055 | struct iattr attr; | |
1056 | int status; | |
1057 | ||
1058 | dfprintk(VFS, "NFS: mknod(%s/%ld, %s\n", dir->i_sb->s_id, | |
1059 | dir->i_ino, dentry->d_name.name); | |
1060 | ||
1061 | if (!new_valid_dev(rdev)) | |
1062 | return -EINVAL; | |
1063 | ||
1064 | attr.ia_mode = mode; | |
1065 | attr.ia_valid = ATTR_MODE; | |
1066 | ||
1067 | lock_kernel(); | |
1068 | nfs_begin_data_update(dir); | |
1069 | status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); | |
1070 | nfs_end_data_update(dir); | |
1071 | if (status != 0) | |
1072 | goto out_err; | |
1073 | nfs_renew_times(dentry); | |
1074 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
1075 | unlock_kernel(); | |
1076 | return 0; | |
1077 | out_err: | |
1078 | unlock_kernel(); | |
1079 | d_drop(dentry); | |
1080 | return status; | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * See comments for nfs_proc_create regarding failed operations. | |
1085 | */ | |
1086 | static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1087 | { | |
1088 | struct iattr attr; | |
1089 | int error; | |
1090 | ||
1091 | dfprintk(VFS, "NFS: mkdir(%s/%ld, %s\n", dir->i_sb->s_id, | |
1092 | dir->i_ino, dentry->d_name.name); | |
1093 | ||
1094 | attr.ia_valid = ATTR_MODE; | |
1095 | attr.ia_mode = mode | S_IFDIR; | |
1096 | ||
1097 | lock_kernel(); | |
1098 | nfs_begin_data_update(dir); | |
1099 | error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); | |
1100 | nfs_end_data_update(dir); | |
1101 | if (error != 0) | |
1102 | goto out_err; | |
1103 | nfs_renew_times(dentry); | |
1104 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
1105 | unlock_kernel(); | |
1106 | return 0; | |
1107 | out_err: | |
1108 | d_drop(dentry); | |
1109 | unlock_kernel(); | |
1110 | return error; | |
1111 | } | |
1112 | ||
1113 | static int nfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1114 | { | |
1115 | int error; | |
1116 | ||
1117 | dfprintk(VFS, "NFS: rmdir(%s/%ld, %s\n", dir->i_sb->s_id, | |
1118 | dir->i_ino, dentry->d_name.name); | |
1119 | ||
1120 | lock_kernel(); | |
1121 | nfs_begin_data_update(dir); | |
1122 | error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); | |
1123 | /* Ensure the VFS deletes this inode */ | |
1124 | if (error == 0 && dentry->d_inode != NULL) | |
1125 | dentry->d_inode->i_nlink = 0; | |
1126 | nfs_end_data_update(dir); | |
1127 | unlock_kernel(); | |
1128 | ||
1129 | return error; | |
1130 | } | |
1131 | ||
1132 | static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) | |
1133 | { | |
1134 | static unsigned int sillycounter; | |
1135 | const int i_inosize = sizeof(dir->i_ino)*2; | |
1136 | const int countersize = sizeof(sillycounter)*2; | |
1137 | const int slen = sizeof(".nfs") + i_inosize + countersize - 1; | |
1138 | char silly[slen+1]; | |
1139 | struct qstr qsilly; | |
1140 | struct dentry *sdentry; | |
1141 | int error = -EIO; | |
1142 | ||
1143 | dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", | |
1144 | dentry->d_parent->d_name.name, dentry->d_name.name, | |
1145 | atomic_read(&dentry->d_count)); | |
1146 | ||
1147 | #ifdef NFS_PARANOIA | |
1148 | if (!dentry->d_inode) | |
1149 | printk("NFS: silly-renaming %s/%s, negative dentry??\n", | |
1150 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
1151 | #endif | |
1152 | /* | |
1153 | * We don't allow a dentry to be silly-renamed twice. | |
1154 | */ | |
1155 | error = -EBUSY; | |
1156 | if (dentry->d_flags & DCACHE_NFSFS_RENAMED) | |
1157 | goto out; | |
1158 | ||
1159 | sprintf(silly, ".nfs%*.*lx", | |
1160 | i_inosize, i_inosize, dentry->d_inode->i_ino); | |
1161 | ||
1162 | sdentry = NULL; | |
1163 | do { | |
1164 | char *suffix = silly + slen - countersize; | |
1165 | ||
1166 | dput(sdentry); | |
1167 | sillycounter++; | |
1168 | sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); | |
1169 | ||
1170 | dfprintk(VFS, "trying to rename %s to %s\n", | |
1171 | dentry->d_name.name, silly); | |
1172 | ||
1173 | sdentry = lookup_one_len(silly, dentry->d_parent, slen); | |
1174 | /* | |
1175 | * N.B. Better to return EBUSY here ... it could be | |
1176 | * dangerous to delete the file while it's in use. | |
1177 | */ | |
1178 | if (IS_ERR(sdentry)) | |
1179 | goto out; | |
1180 | } while(sdentry->d_inode != NULL); /* need negative lookup */ | |
1181 | ||
1182 | qsilly.name = silly; | |
1183 | qsilly.len = strlen(silly); | |
1184 | nfs_begin_data_update(dir); | |
1185 | if (dentry->d_inode) { | |
1186 | nfs_begin_data_update(dentry->d_inode); | |
1187 | error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, | |
1188 | dir, &qsilly); | |
1189 | nfs_end_data_update(dentry->d_inode); | |
1190 | } else | |
1191 | error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, | |
1192 | dir, &qsilly); | |
1193 | nfs_end_data_update(dir); | |
1194 | if (!error) { | |
1195 | nfs_renew_times(dentry); | |
1196 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
1197 | d_move(dentry, sdentry); | |
1198 | error = nfs_async_unlink(dentry); | |
1199 | /* If we return 0 we don't unlink */ | |
1200 | } | |
1201 | dput(sdentry); | |
1202 | out: | |
1203 | return error; | |
1204 | } | |
1205 | ||
1206 | /* | |
1207 | * Remove a file after making sure there are no pending writes, | |
1208 | * and after checking that the file has only one user. | |
1209 | * | |
1210 | * We invalidate the attribute cache and free the inode prior to the operation | |
1211 | * to avoid possible races if the server reuses the inode. | |
1212 | */ | |
1213 | static int nfs_safe_remove(struct dentry *dentry) | |
1214 | { | |
1215 | struct inode *dir = dentry->d_parent->d_inode; | |
1216 | struct inode *inode = dentry->d_inode; | |
1217 | int error = -EBUSY; | |
1218 | ||
1219 | dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", | |
1220 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
1221 | ||
1222 | /* If the dentry was sillyrenamed, we simply call d_delete() */ | |
1223 | if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { | |
1224 | error = 0; | |
1225 | goto out; | |
1226 | } | |
1227 | ||
1228 | nfs_begin_data_update(dir); | |
1229 | if (inode != NULL) { | |
1230 | nfs_begin_data_update(inode); | |
1231 | error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); | |
1232 | /* The VFS may want to delete this inode */ | |
1233 | if (error == 0) | |
1234 | inode->i_nlink--; | |
1235 | nfs_end_data_update(inode); | |
1236 | } else | |
1237 | error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); | |
1238 | nfs_end_data_update(dir); | |
1239 | out: | |
1240 | return error; | |
1241 | } | |
1242 | ||
1243 | /* We do silly rename. In case sillyrename() returns -EBUSY, the inode | |
1244 | * belongs to an active ".nfs..." file and we return -EBUSY. | |
1245 | * | |
1246 | * If sillyrename() returns 0, we do nothing, otherwise we unlink. | |
1247 | */ | |
1248 | static int nfs_unlink(struct inode *dir, struct dentry *dentry) | |
1249 | { | |
1250 | int error; | |
1251 | int need_rehash = 0; | |
1252 | ||
1253 | dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, | |
1254 | dir->i_ino, dentry->d_name.name); | |
1255 | ||
1256 | lock_kernel(); | |
1257 | spin_lock(&dcache_lock); | |
1258 | spin_lock(&dentry->d_lock); | |
1259 | if (atomic_read(&dentry->d_count) > 1) { | |
1260 | spin_unlock(&dentry->d_lock); | |
1261 | spin_unlock(&dcache_lock); | |
1262 | error = nfs_sillyrename(dir, dentry); | |
1263 | unlock_kernel(); | |
1264 | return error; | |
1265 | } | |
1266 | if (!d_unhashed(dentry)) { | |
1267 | __d_drop(dentry); | |
1268 | need_rehash = 1; | |
1269 | } | |
1270 | spin_unlock(&dentry->d_lock); | |
1271 | spin_unlock(&dcache_lock); | |
1272 | error = nfs_safe_remove(dentry); | |
1273 | if (!error) { | |
1274 | nfs_renew_times(dentry); | |
1275 | nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); | |
1276 | } else if (need_rehash) | |
1277 | d_rehash(dentry); | |
1278 | unlock_kernel(); | |
1279 | return error; | |
1280 | } | |
1281 | ||
1282 | static int | |
1283 | nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1284 | { | |
1285 | struct iattr attr; | |
1286 | struct nfs_fattr sym_attr; | |
1287 | struct nfs_fh sym_fh; | |
1288 | struct qstr qsymname; | |
1289 | int error; | |
1290 | ||
1291 | dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, | |
1292 | dir->i_ino, dentry->d_name.name, symname); | |
1293 | ||
1294 | #ifdef NFS_PARANOIA | |
1295 | if (dentry->d_inode) | |
1296 | printk("nfs_proc_symlink: %s/%s not negative!\n", | |
1297 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
1298 | #endif | |
1299 | /* | |
1300 | * Fill in the sattr for the call. | |
1301 | * Note: SunOS 4.1.2 crashes if the mode isn't initialized! | |
1302 | */ | |
1303 | attr.ia_valid = ATTR_MODE; | |
1304 | attr.ia_mode = S_IFLNK | S_IRWXUGO; | |
1305 | ||
1306 | qsymname.name = symname; | |
1307 | qsymname.len = strlen(symname); | |
1308 | ||
1309 | lock_kernel(); | |
1310 | nfs_begin_data_update(dir); | |
1311 | error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname, | |
1312 | &attr, &sym_fh, &sym_attr); | |
1313 | nfs_end_data_update(dir); | |
1314 | if (!error) { | |
1315 | error = nfs_instantiate(dentry, &sym_fh, &sym_attr); | |
1316 | } else { | |
1317 | if (error == -EEXIST) | |
1318 | printk("nfs_proc_symlink: %s/%s already exists??\n", | |
1319 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
1320 | d_drop(dentry); | |
1321 | } | |
1322 | unlock_kernel(); | |
1323 | return error; | |
1324 | } | |
1325 | ||
1326 | static int | |
1327 | nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1328 | { | |
1329 | struct inode *inode = old_dentry->d_inode; | |
1330 | int error; | |
1331 | ||
1332 | dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", | |
1333 | old_dentry->d_parent->d_name.name, old_dentry->d_name.name, | |
1334 | dentry->d_parent->d_name.name, dentry->d_name.name); | |
1335 | ||
1336 | /* | |
1337 | * Drop the dentry in advance to force a new lookup. | |
1338 | * Since nfs_proc_link doesn't return a file handle, | |
1339 | * we can't use the existing dentry. | |
1340 | */ | |
1341 | lock_kernel(); | |
1342 | d_drop(dentry); | |
1343 | ||
1344 | nfs_begin_data_update(dir); | |
1345 | nfs_begin_data_update(inode); | |
1346 | error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); | |
1347 | nfs_end_data_update(inode); | |
1348 | nfs_end_data_update(dir); | |
1349 | unlock_kernel(); | |
1350 | return error; | |
1351 | } | |
1352 | ||
1353 | /* | |
1354 | * RENAME | |
1355 | * FIXME: Some nfsds, like the Linux user space nfsd, may generate a | |
1356 | * different file handle for the same inode after a rename (e.g. when | |
1357 | * moving to a different directory). A fail-safe method to do so would | |
1358 | * be to look up old_dir/old_name, create a link to new_dir/new_name and | |
1359 | * rename the old file using the sillyrename stuff. This way, the original | |
1360 | * file in old_dir will go away when the last process iput()s the inode. | |
1361 | * | |
1362 | * FIXED. | |
1363 | * | |
1364 | * It actually works quite well. One needs to have the possibility for | |
1365 | * at least one ".nfs..." file in each directory the file ever gets | |
1366 | * moved or linked to which happens automagically with the new | |
1367 | * implementation that only depends on the dcache stuff instead of | |
1368 | * using the inode layer | |
1369 | * | |
1370 | * Unfortunately, things are a little more complicated than indicated | |
1371 | * above. For a cross-directory move, we want to make sure we can get | |
1372 | * rid of the old inode after the operation. This means there must be | |
1373 | * no pending writes (if it's a file), and the use count must be 1. | |
1374 | * If these conditions are met, we can drop the dentries before doing | |
1375 | * the rename. | |
1376 | */ | |
1377 | static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, | |
1378 | struct inode *new_dir, struct dentry *new_dentry) | |
1379 | { | |
1380 | struct inode *old_inode = old_dentry->d_inode; | |
1381 | struct inode *new_inode = new_dentry->d_inode; | |
1382 | struct dentry *dentry = NULL, *rehash = NULL; | |
1383 | int error = -EBUSY; | |
1384 | ||
1385 | /* | |
1386 | * To prevent any new references to the target during the rename, | |
1387 | * we unhash the dentry and free the inode in advance. | |
1388 | */ | |
1389 | lock_kernel(); | |
1390 | if (!d_unhashed(new_dentry)) { | |
1391 | d_drop(new_dentry); | |
1392 | rehash = new_dentry; | |
1393 | } | |
1394 | ||
1395 | dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", | |
1396 | old_dentry->d_parent->d_name.name, old_dentry->d_name.name, | |
1397 | new_dentry->d_parent->d_name.name, new_dentry->d_name.name, | |
1398 | atomic_read(&new_dentry->d_count)); | |
1399 | ||
1400 | /* | |
1401 | * First check whether the target is busy ... we can't | |
1402 | * safely do _any_ rename if the target is in use. | |
1403 | * | |
1404 | * For files, make a copy of the dentry and then do a | |
1405 | * silly-rename. If the silly-rename succeeds, the | |
1406 | * copied dentry is hashed and becomes the new target. | |
1407 | */ | |
1408 | if (!new_inode) | |
1409 | goto go_ahead; | |
1410 | if (S_ISDIR(new_inode->i_mode)) | |
1411 | goto out; | |
1412 | else if (atomic_read(&new_dentry->d_count) > 2) { | |
1413 | int err; | |
1414 | /* copy the target dentry's name */ | |
1415 | dentry = d_alloc(new_dentry->d_parent, | |
1416 | &new_dentry->d_name); | |
1417 | if (!dentry) | |
1418 | goto out; | |
1419 | ||
1420 | /* silly-rename the existing target ... */ | |
1421 | err = nfs_sillyrename(new_dir, new_dentry); | |
1422 | if (!err) { | |
1423 | new_dentry = rehash = dentry; | |
1424 | new_inode = NULL; | |
1425 | /* instantiate the replacement target */ | |
1426 | d_instantiate(new_dentry, NULL); | |
1427 | } else if (atomic_read(&new_dentry->d_count) > 1) { | |
1428 | /* dentry still busy? */ | |
1429 | #ifdef NFS_PARANOIA | |
1430 | printk("nfs_rename: target %s/%s busy, d_count=%d\n", | |
1431 | new_dentry->d_parent->d_name.name, | |
1432 | new_dentry->d_name.name, | |
1433 | atomic_read(&new_dentry->d_count)); | |
1434 | #endif | |
1435 | goto out; | |
1436 | } | |
1437 | } | |
1438 | ||
1439 | go_ahead: | |
1440 | /* | |
1441 | * ... prune child dentries and writebacks if needed. | |
1442 | */ | |
1443 | if (atomic_read(&old_dentry->d_count) > 1) { | |
1444 | nfs_wb_all(old_inode); | |
1445 | shrink_dcache_parent(old_dentry); | |
1446 | } | |
1447 | ||
1448 | if (new_inode) | |
1449 | d_delete(new_dentry); | |
1450 | ||
1451 | nfs_begin_data_update(old_dir); | |
1452 | nfs_begin_data_update(new_dir); | |
1453 | nfs_begin_data_update(old_inode); | |
1454 | error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, | |
1455 | new_dir, &new_dentry->d_name); | |
1456 | nfs_end_data_update(old_inode); | |
1457 | nfs_end_data_update(new_dir); | |
1458 | nfs_end_data_update(old_dir); | |
1459 | out: | |
1460 | if (rehash) | |
1461 | d_rehash(rehash); | |
1462 | if (!error) { | |
1463 | if (!S_ISDIR(old_inode->i_mode)) | |
1464 | d_move(old_dentry, new_dentry); | |
1465 | nfs_renew_times(new_dentry); | |
1466 | nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir)); | |
1467 | } | |
1468 | ||
1469 | /* new dentry created? */ | |
1470 | if (dentry) | |
1471 | dput(dentry); | |
1472 | unlock_kernel(); | |
1473 | return error; | |
1474 | } | |
1475 | ||
1476 | int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) | |
1477 | { | |
1478 | struct nfs_access_entry *cache = &NFS_I(inode)->cache_access; | |
1479 | ||
1480 | if (cache->cred != cred | |
1481 | || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)) | |
1482 | || (NFS_FLAGS(inode) & NFS_INO_INVALID_ACCESS)) | |
1483 | return -ENOENT; | |
1484 | memcpy(res, cache, sizeof(*res)); | |
1485 | return 0; | |
1486 | } | |
1487 | ||
1488 | void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) | |
1489 | { | |
1490 | struct nfs_access_entry *cache = &NFS_I(inode)->cache_access; | |
1491 | ||
1492 | if (cache->cred != set->cred) { | |
1493 | if (cache->cred) | |
1494 | put_rpccred(cache->cred); | |
1495 | cache->cred = get_rpccred(set->cred); | |
1496 | } | |
1497 | NFS_FLAGS(inode) &= ~NFS_INO_INVALID_ACCESS; | |
1498 | cache->jiffies = set->jiffies; | |
1499 | cache->mask = set->mask; | |
1500 | } | |
1501 | ||
1502 | static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) | |
1503 | { | |
1504 | struct nfs_access_entry cache; | |
1505 | int status; | |
1506 | ||
1507 | status = nfs_access_get_cached(inode, cred, &cache); | |
1508 | if (status == 0) | |
1509 | goto out; | |
1510 | ||
1511 | /* Be clever: ask server to check for all possible rights */ | |
1512 | cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; | |
1513 | cache.cred = cred; | |
1514 | cache.jiffies = jiffies; | |
1515 | status = NFS_PROTO(inode)->access(inode, &cache); | |
1516 | if (status != 0) | |
1517 | return status; | |
1518 | nfs_access_add_cache(inode, &cache); | |
1519 | out: | |
1520 | if ((cache.mask & mask) == mask) | |
1521 | return 0; | |
1522 | return -EACCES; | |
1523 | } | |
1524 | ||
1525 | int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) | |
1526 | { | |
1527 | struct rpc_cred *cred; | |
1528 | int res = 0; | |
1529 | ||
1530 | if (mask == 0) | |
1531 | goto out; | |
1532 | /* Is this sys_access() ? */ | |
1533 | if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) | |
1534 | goto force_lookup; | |
1535 | ||
1536 | switch (inode->i_mode & S_IFMT) { | |
1537 | case S_IFLNK: | |
1538 | goto out; | |
1539 | case S_IFREG: | |
1540 | /* NFSv4 has atomic_open... */ | |
1541 | if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) | |
1542 | && nd != NULL | |
1543 | && (nd->flags & LOOKUP_OPEN)) | |
1544 | goto out; | |
1545 | break; | |
1546 | case S_IFDIR: | |
1547 | /* | |
1548 | * Optimize away all write operations, since the server | |
1549 | * will check permissions when we perform the op. | |
1550 | */ | |
1551 | if ((mask & MAY_WRITE) && !(mask & MAY_READ)) | |
1552 | goto out; | |
1553 | } | |
1554 | ||
1555 | force_lookup: | |
1556 | lock_kernel(); | |
1557 | ||
1558 | if (!NFS_PROTO(inode)->access) | |
1559 | goto out_notsup; | |
1560 | ||
1561 | cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); | |
1562 | if (!IS_ERR(cred)) { | |
1563 | res = nfs_do_access(inode, cred, mask); | |
1564 | put_rpccred(cred); | |
1565 | } else | |
1566 | res = PTR_ERR(cred); | |
1567 | unlock_kernel(); | |
1568 | out: | |
1569 | return res; | |
1570 | out_notsup: | |
1571 | res = nfs_revalidate_inode(NFS_SERVER(inode), inode); | |
1572 | if (res == 0) | |
1573 | res = generic_permission(inode, mask, NULL); | |
1574 | unlock_kernel(); | |
1575 | return res; | |
1576 | } | |
1577 | ||
1578 | /* | |
1579 | * Local variables: | |
1580 | * version-control: t | |
1581 | * kept-new-versions: 5 | |
1582 | * End: | |
1583 | */ |