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e14748e8 SF |
1 | /* |
2 | * Copyright (C) 2005-2016 Junjiro R. Okajima | |
3 | * | |
4 | * This program, aufs is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | /* | |
19 | * inode operations (del entry) | |
20 | */ | |
21 | ||
22 | #include "aufs.h" | |
23 | ||
24 | /* | |
25 | * decide if a new whiteout for @dentry is necessary or not. | |
26 | * when it is necessary, prepare the parent dir for the upper branch whose | |
27 | * branch index is @bcpup for creation. the actual creation of the whiteout will | |
28 | * be done by caller. | |
29 | * return value: | |
30 | * 0: wh is unnecessary | |
31 | * plus: wh is necessary | |
32 | * minus: error | |
33 | */ | |
34 | int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup) | |
35 | { | |
36 | int need_wh, err; | |
37 | aufs_bindex_t btop; | |
38 | struct super_block *sb; | |
39 | ||
40 | sb = dentry->d_sb; | |
41 | btop = au_dbtop(dentry); | |
42 | if (*bcpup < 0) { | |
43 | *bcpup = btop; | |
44 | if (au_test_ro(sb, btop, d_inode(dentry))) { | |
45 | err = AuWbrCopyup(au_sbi(sb), dentry); | |
46 | *bcpup = err; | |
47 | if (unlikely(err < 0)) | |
48 | goto out; | |
49 | } | |
50 | } else | |
51 | AuDebugOn(btop < *bcpup | |
52 | || au_test_ro(sb, *bcpup, d_inode(dentry))); | |
53 | AuDbg("bcpup %d, btop %d\n", *bcpup, btop); | |
54 | ||
55 | if (*bcpup != btop) { | |
56 | err = au_cpup_dirs(dentry, *bcpup); | |
57 | if (unlikely(err)) | |
58 | goto out; | |
59 | need_wh = 1; | |
60 | } else { | |
61 | struct au_dinfo *dinfo, *tmp; | |
62 | ||
63 | need_wh = -ENOMEM; | |
64 | dinfo = au_di(dentry); | |
65 | tmp = au_di_alloc(sb, AuLsc_DI_TMP); | |
66 | if (tmp) { | |
67 | au_di_cp(tmp, dinfo); | |
68 | au_di_swap(tmp, dinfo); | |
69 | /* returns the number of positive dentries */ | |
70 | need_wh = au_lkup_dentry(dentry, btop + 1, | |
71 | /* AuLkup_IGNORE_PERM */ 0); | |
72 | au_di_swap(tmp, dinfo); | |
73 | au_rw_write_unlock(&tmp->di_rwsem); | |
74 | au_di_free(tmp); | |
75 | } | |
76 | } | |
77 | AuDbg("need_wh %d\n", need_wh); | |
78 | err = need_wh; | |
79 | ||
80 | out: | |
81 | return err; | |
82 | } | |
83 | ||
84 | /* | |
85 | * simple tests for the del-entry operations. | |
86 | * following the checks in vfs, plus the parent-child relationship. | |
87 | */ | |
88 | int au_may_del(struct dentry *dentry, aufs_bindex_t bindex, | |
89 | struct dentry *h_parent, int isdir) | |
90 | { | |
91 | int err; | |
92 | umode_t h_mode; | |
93 | struct dentry *h_dentry, *h_latest; | |
94 | struct inode *h_inode; | |
95 | ||
96 | h_dentry = au_h_dptr(dentry, bindex); | |
97 | if (d_really_is_positive(dentry)) { | |
98 | err = -ENOENT; | |
99 | if (unlikely(d_is_negative(h_dentry))) | |
100 | goto out; | |
101 | h_inode = d_inode(h_dentry); | |
102 | if (unlikely(!h_inode->i_nlink)) | |
103 | goto out; | |
104 | ||
105 | h_mode = h_inode->i_mode; | |
106 | if (!isdir) { | |
107 | err = -EISDIR; | |
108 | if (unlikely(S_ISDIR(h_mode))) | |
109 | goto out; | |
110 | } else if (unlikely(!S_ISDIR(h_mode))) { | |
111 | err = -ENOTDIR; | |
112 | goto out; | |
113 | } | |
114 | } else { | |
115 | /* rename(2) case */ | |
116 | err = -EIO; | |
117 | if (unlikely(d_is_positive(h_dentry))) | |
118 | goto out; | |
119 | } | |
120 | ||
121 | err = -ENOENT; | |
122 | /* expected parent dir is locked */ | |
123 | if (unlikely(h_parent != h_dentry->d_parent)) | |
124 | goto out; | |
125 | err = 0; | |
126 | ||
127 | /* | |
128 | * rmdir a dir may break the consistency on some filesystem. | |
129 | * let's try heavy test. | |
130 | */ | |
131 | err = -EACCES; | |
132 | if (unlikely(!au_opt_test(au_mntflags(dentry->d_sb), DIRPERM1) | |
133 | && au_test_h_perm(d_inode(h_parent), | |
134 | MAY_EXEC | MAY_WRITE))) | |
135 | goto out; | |
136 | ||
137 | h_latest = au_sio_lkup_one(&dentry->d_name, h_parent); | |
138 | err = -EIO; | |
139 | if (IS_ERR(h_latest)) | |
140 | goto out; | |
141 | if (h_latest == h_dentry) | |
142 | err = 0; | |
143 | dput(h_latest); | |
144 | ||
145 | out: | |
146 | return err; | |
147 | } | |
148 | ||
149 | /* | |
150 | * decide the branch where we operate for @dentry. the branch index will be set | |
151 | * @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent | |
152 | * dir for reverting. | |
153 | * when a new whiteout is necessary, create it. | |
154 | */ | |
155 | static struct dentry* | |
156 | lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup, | |
157 | struct au_dtime *dt, struct au_pin *pin) | |
158 | { | |
159 | struct dentry *wh_dentry; | |
160 | struct super_block *sb; | |
161 | struct path h_path; | |
162 | int err, need_wh; | |
163 | unsigned int udba; | |
164 | aufs_bindex_t bcpup; | |
165 | ||
166 | need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup); | |
167 | wh_dentry = ERR_PTR(need_wh); | |
168 | if (unlikely(need_wh < 0)) | |
169 | goto out; | |
170 | ||
171 | sb = dentry->d_sb; | |
172 | udba = au_opt_udba(sb); | |
173 | bcpup = *rbcpup; | |
174 | err = au_pin(pin, dentry, bcpup, udba, | |
175 | AuPin_DI_LOCKED | AuPin_MNT_WRITE); | |
176 | wh_dentry = ERR_PTR(err); | |
177 | if (unlikely(err)) | |
178 | goto out; | |
179 | ||
180 | h_path.dentry = au_pinned_h_parent(pin); | |
181 | if (udba != AuOpt_UDBA_NONE | |
182 | && au_dbtop(dentry) == bcpup) { | |
183 | err = au_may_del(dentry, bcpup, h_path.dentry, isdir); | |
184 | wh_dentry = ERR_PTR(err); | |
185 | if (unlikely(err)) | |
186 | goto out_unpin; | |
187 | } | |
188 | ||
189 | h_path.mnt = au_sbr_mnt(sb, bcpup); | |
190 | au_dtime_store(dt, au_pinned_parent(pin), &h_path); | |
191 | wh_dentry = NULL; | |
192 | if (!need_wh) | |
193 | goto out; /* success, no need to create whiteout */ | |
194 | ||
195 | wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry); | |
196 | if (IS_ERR(wh_dentry)) | |
197 | goto out_unpin; | |
198 | ||
199 | /* returns with the parent is locked and wh_dentry is dget-ed */ | |
200 | goto out; /* success */ | |
201 | ||
202 | out_unpin: | |
203 | au_unpin(pin); | |
204 | out: | |
205 | return wh_dentry; | |
206 | } | |
207 | ||
208 | /* | |
209 | * when removing a dir, rename it to a unique temporary whiteout-ed name first | |
210 | * in order to be revertible and save time for removing many child whiteouts | |
211 | * under the dir. | |
212 | * returns 1 when there are too many child whiteout and caller should remove | |
213 | * them asynchronously. returns 0 when the number of children is enough small to | |
214 | * remove now or the branch fs is a remote fs. | |
215 | * otherwise return an error. | |
216 | */ | |
217 | static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex, | |
218 | struct au_nhash *whlist, struct inode *dir) | |
219 | { | |
220 | int rmdir_later, err, dirwh; | |
221 | struct dentry *h_dentry; | |
222 | struct super_block *sb; | |
223 | struct inode *inode; | |
224 | ||
225 | sb = dentry->d_sb; | |
226 | SiMustAnyLock(sb); | |
227 | h_dentry = au_h_dptr(dentry, bindex); | |
228 | err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex)); | |
229 | if (unlikely(err)) | |
230 | goto out; | |
231 | ||
232 | /* stop monitoring */ | |
233 | inode = d_inode(dentry); | |
234 | au_hn_free(au_hi(inode, bindex)); | |
235 | ||
236 | if (!au_test_fs_remote(h_dentry->d_sb)) { | |
237 | dirwh = au_sbi(sb)->si_dirwh; | |
238 | rmdir_later = (dirwh <= 1); | |
239 | if (!rmdir_later) | |
240 | rmdir_later = au_nhash_test_longer_wh(whlist, bindex, | |
241 | dirwh); | |
242 | if (rmdir_later) | |
243 | return rmdir_later; | |
244 | } | |
245 | ||
246 | err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist); | |
247 | if (unlikely(err)) { | |
248 | AuIOErr("rmdir %pd, b%d failed, %d. ignored\n", | |
249 | h_dentry, bindex, err); | |
250 | err = 0; | |
251 | } | |
252 | ||
253 | out: | |
254 | AuTraceErr(err); | |
255 | return err; | |
256 | } | |
257 | ||
258 | /* | |
259 | * final procedure for deleting a entry. | |
260 | * maintain dentry and iattr. | |
261 | */ | |
262 | static void epilog(struct inode *dir, struct dentry *dentry, | |
263 | aufs_bindex_t bindex) | |
264 | { | |
265 | struct inode *inode; | |
266 | ||
267 | inode = d_inode(dentry); | |
268 | d_drop(dentry); | |
269 | inode->i_ctime = dir->i_ctime; | |
270 | ||
271 | au_dir_ts(dir, bindex); | |
272 | dir->i_version++; | |
273 | } | |
274 | ||
275 | /* | |
276 | * when an error happened, remove the created whiteout and revert everything. | |
277 | */ | |
278 | static int do_revert(int err, struct inode *dir, aufs_bindex_t bindex, | |
279 | aufs_bindex_t bwh, struct dentry *wh_dentry, | |
280 | struct dentry *dentry, struct au_dtime *dt) | |
281 | { | |
282 | int rerr; | |
283 | struct path h_path = { | |
284 | .dentry = wh_dentry, | |
285 | .mnt = au_sbr_mnt(dir->i_sb, bindex) | |
286 | }; | |
287 | ||
288 | rerr = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path, dentry); | |
289 | if (!rerr) { | |
290 | au_set_dbwh(dentry, bwh); | |
291 | au_dtime_revert(dt); | |
292 | return 0; | |
293 | } | |
294 | ||
295 | AuIOErr("%pd reverting whiteout failed(%d, %d)\n", dentry, err, rerr); | |
296 | return -EIO; | |
297 | } | |
298 | ||
299 | /* ---------------------------------------------------------------------- */ | |
300 | ||
301 | int aufs_unlink(struct inode *dir, struct dentry *dentry) | |
302 | { | |
303 | int err; | |
304 | aufs_bindex_t bwh, bindex, btop; | |
305 | struct inode *inode, *h_dir, *delegated; | |
306 | struct dentry *parent, *wh_dentry; | |
307 | /* to reuduce stack size */ | |
308 | struct { | |
309 | struct au_dtime dt; | |
310 | struct au_pin pin; | |
311 | struct path h_path; | |
312 | } *a; | |
313 | ||
314 | IMustLock(dir); | |
315 | ||
316 | err = -ENOMEM; | |
317 | a = kmalloc(sizeof(*a), GFP_NOFS); | |
318 | if (unlikely(!a)) | |
319 | goto out; | |
320 | ||
321 | err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN); | |
322 | if (unlikely(err)) | |
323 | goto out_free; | |
324 | err = au_d_hashed_positive(dentry); | |
325 | if (unlikely(err)) | |
326 | goto out_unlock; | |
327 | inode = d_inode(dentry); | |
328 | IMustLock(inode); | |
329 | err = -EISDIR; | |
330 | if (unlikely(d_is_dir(dentry))) | |
331 | goto out_unlock; /* possible? */ | |
332 | ||
333 | btop = au_dbtop(dentry); | |
334 | bwh = au_dbwh(dentry); | |
335 | bindex = -1; | |
336 | parent = dentry->d_parent; /* dir inode is locked */ | |
337 | di_write_lock_parent(parent); | |
338 | wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &a->dt, | |
339 | &a->pin); | |
340 | err = PTR_ERR(wh_dentry); | |
341 | if (IS_ERR(wh_dentry)) | |
342 | goto out_parent; | |
343 | ||
344 | a->h_path.mnt = au_sbr_mnt(dentry->d_sb, btop); | |
345 | a->h_path.dentry = au_h_dptr(dentry, btop); | |
346 | dget(a->h_path.dentry); | |
347 | if (bindex == btop) { | |
348 | h_dir = au_pinned_h_dir(&a->pin); | |
349 | delegated = NULL; | |
350 | err = vfsub_unlink(h_dir, &a->h_path, &delegated, /*force*/0); | |
351 | if (unlikely(err == -EWOULDBLOCK)) { | |
352 | pr_warn("cannot retry for NFSv4 delegation" | |
353 | " for an internal unlink\n"); | |
354 | iput(delegated); | |
355 | } | |
356 | } else { | |
357 | /* dir inode is locked */ | |
358 | h_dir = d_inode(wh_dentry->d_parent); | |
359 | IMustLock(h_dir); | |
360 | err = 0; | |
361 | } | |
362 | ||
363 | if (!err) { | |
364 | vfsub_drop_nlink(inode); | |
365 | epilog(dir, dentry, bindex); | |
366 | ||
367 | /* update target timestamps */ | |
368 | if (bindex == btop) { | |
369 | vfsub_update_h_iattr(&a->h_path, /*did*/NULL); | |
370 | /*ignore*/ | |
371 | inode->i_ctime = d_inode(a->h_path.dentry)->i_ctime; | |
372 | } else | |
373 | /* todo: this timestamp may be reverted later */ | |
374 | inode->i_ctime = h_dir->i_ctime; | |
375 | goto out_unpin; /* success */ | |
376 | } | |
377 | ||
378 | /* revert */ | |
379 | if (wh_dentry) { | |
380 | int rerr; | |
381 | ||
382 | rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry, | |
383 | &a->dt); | |
384 | if (rerr) | |
385 | err = rerr; | |
386 | } | |
387 | ||
388 | out_unpin: | |
389 | au_unpin(&a->pin); | |
390 | dput(wh_dentry); | |
391 | dput(a->h_path.dentry); | |
392 | out_parent: | |
393 | di_write_unlock(parent); | |
394 | out_unlock: | |
395 | aufs_read_unlock(dentry, AuLock_DW); | |
396 | out_free: | |
397 | au_delayed_kfree(a); | |
398 | out: | |
399 | return err; | |
400 | } | |
401 | ||
402 | int aufs_rmdir(struct inode *dir, struct dentry *dentry) | |
403 | { | |
404 | int err, rmdir_later; | |
405 | aufs_bindex_t bwh, bindex, btop; | |
406 | struct inode *inode; | |
407 | struct dentry *parent, *wh_dentry, *h_dentry; | |
408 | struct au_whtmp_rmdir *args; | |
409 | /* to reuduce stack size */ | |
410 | struct { | |
411 | struct au_dtime dt; | |
412 | struct au_pin pin; | |
413 | } *a; | |
414 | ||
415 | IMustLock(dir); | |
416 | ||
417 | err = -ENOMEM; | |
418 | a = kmalloc(sizeof(*a), GFP_NOFS); | |
419 | if (unlikely(!a)) | |
420 | goto out; | |
421 | ||
422 | err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN); | |
423 | if (unlikely(err)) | |
424 | goto out_free; | |
425 | err = au_alive_dir(dentry); | |
426 | if (unlikely(err)) | |
427 | goto out_unlock; | |
428 | inode = d_inode(dentry); | |
429 | IMustLock(inode); | |
430 | err = -ENOTDIR; | |
431 | if (unlikely(!d_is_dir(dentry))) | |
432 | goto out_unlock; /* possible? */ | |
433 | ||
434 | err = -ENOMEM; | |
435 | args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS); | |
436 | if (unlikely(!args)) | |
437 | goto out_unlock; | |
438 | ||
439 | parent = dentry->d_parent; /* dir inode is locked */ | |
440 | di_write_lock_parent(parent); | |
441 | err = au_test_empty(dentry, &args->whlist); | |
442 | if (unlikely(err)) | |
443 | goto out_parent; | |
444 | ||
445 | btop = au_dbtop(dentry); | |
446 | bwh = au_dbwh(dentry); | |
447 | bindex = -1; | |
448 | wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &a->dt, | |
449 | &a->pin); | |
450 | err = PTR_ERR(wh_dentry); | |
451 | if (IS_ERR(wh_dentry)) | |
452 | goto out_parent; | |
453 | ||
454 | h_dentry = au_h_dptr(dentry, btop); | |
455 | dget(h_dentry); | |
456 | rmdir_later = 0; | |
457 | if (bindex == btop) { | |
458 | err = renwh_and_rmdir(dentry, btop, &args->whlist, dir); | |
459 | if (err > 0) { | |
460 | rmdir_later = err; | |
461 | err = 0; | |
462 | } | |
463 | } else { | |
464 | /* stop monitoring */ | |
465 | au_hn_free(au_hi(inode, btop)); | |
466 | ||
467 | /* dir inode is locked */ | |
468 | IMustLock(d_inode(wh_dentry->d_parent)); | |
469 | err = 0; | |
470 | } | |
471 | ||
472 | if (!err) { | |
473 | vfsub_dead_dir(inode); | |
474 | au_set_dbdiropq(dentry, -1); | |
475 | epilog(dir, dentry, bindex); | |
476 | ||
477 | if (rmdir_later) { | |
478 | au_whtmp_kick_rmdir(dir, btop, h_dentry, args); | |
479 | args = NULL; | |
480 | } | |
481 | ||
482 | goto out_unpin; /* success */ | |
483 | } | |
484 | ||
485 | /* revert */ | |
486 | AuLabel(revert); | |
487 | if (wh_dentry) { | |
488 | int rerr; | |
489 | ||
490 | rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry, | |
491 | &a->dt); | |
492 | if (rerr) | |
493 | err = rerr; | |
494 | } | |
495 | ||
496 | out_unpin: | |
497 | au_unpin(&a->pin); | |
498 | dput(wh_dentry); | |
499 | dput(h_dentry); | |
500 | out_parent: | |
501 | di_write_unlock(parent); | |
502 | if (args) | |
503 | au_whtmp_rmdir_free(args); | |
504 | out_unlock: | |
505 | aufs_read_unlock(dentry, AuLock_DW); | |
506 | out_free: | |
507 | au_delayed_kfree(a); | |
508 | out: | |
509 | AuTraceErr(err); | |
510 | return err; | |
511 | } |