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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ccd979bd MF |
2 | /* -*- mode: c; c-basic-offset: 8; -*- |
3 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
4 | * | |
5 | * dcache.c | |
6 | * | |
7 | * dentry cache handling code | |
8 | * | |
9 | * Copyright (C) 2002, 2004 Oracle. All rights reserved. | |
ccd979bd MF |
10 | */ |
11 | ||
12 | #include <linux/fs.h> | |
13 | #include <linux/types.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/namei.h> | |
16 | ||
ccd979bd MF |
17 | #include <cluster/masklog.h> |
18 | ||
19 | #include "ocfs2.h" | |
20 | ||
21 | #include "alloc.h" | |
22 | #include "dcache.h" | |
80c05846 | 23 | #include "dlmglue.h" |
ccd979bd MF |
24 | #include "file.h" |
25 | #include "inode.h" | |
a5b8443b | 26 | #include "ocfs2_trace.h" |
ccd979bd | 27 | |
5e98d492 GR |
28 | void ocfs2_dentry_attach_gen(struct dentry *dentry) |
29 | { | |
30 | unsigned long gen = | |
2b0143b5 DH |
31 | OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen; |
32 | BUG_ON(d_inode(dentry)); | |
5e98d492 GR |
33 | dentry->d_fsdata = (void *)gen; |
34 | } | |
35 | ||
80c05846 | 36 | |
0b728e19 | 37 | static int ocfs2_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
ccd979bd | 38 | { |
34286d66 | 39 | struct inode *inode; |
ccd979bd | 40 | int ret = 0; /* if all else fails, just return false */ |
34286d66 NP |
41 | struct ocfs2_super *osb; |
42 | ||
0b728e19 | 43 | if (flags & LOOKUP_RCU) |
34286d66 NP |
44 | return -ECHILD; |
45 | ||
2b0143b5 | 46 | inode = d_inode(dentry); |
34286d66 | 47 | osb = OCFS2_SB(dentry->d_sb); |
ccd979bd | 48 | |
a5b8443b TM |
49 | trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len, |
50 | dentry->d_name.name); | |
ccd979bd | 51 | |
5e98d492 GR |
52 | /* For a negative dentry - |
53 | * check the generation number of the parent and compare with the | |
54 | * one stored in the inode. | |
55 | */ | |
ccd979bd | 56 | if (inode == NULL) { |
5e98d492 | 57 | unsigned long gen = (unsigned long) dentry->d_fsdata; |
7b9a2378 AV |
58 | unsigned long pgen; |
59 | spin_lock(&dentry->d_lock); | |
2b0143b5 | 60 | pgen = OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen; |
7b9a2378 | 61 | spin_unlock(&dentry->d_lock); |
a5b8443b TM |
62 | trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len, |
63 | dentry->d_name.name, | |
64 | pgen, gen); | |
5e98d492 GR |
65 | if (gen != pgen) |
66 | goto bail; | |
67 | goto valid; | |
ccd979bd MF |
68 | } |
69 | ||
ccd979bd MF |
70 | BUG_ON(!osb); |
71 | ||
80c05846 MF |
72 | if (inode == osb->root_inode || is_bad_inode(inode)) |
73 | goto bail; | |
74 | ||
75 | spin_lock(&OCFS2_I(inode)->ip_lock); | |
76 | /* did we or someone else delete this inode? */ | |
77 | if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) { | |
ccd979bd | 78 | spin_unlock(&OCFS2_I(inode)->ip_lock); |
a5b8443b TM |
79 | trace_ocfs2_dentry_revalidate_delete( |
80 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
80c05846 MF |
81 | goto bail; |
82 | } | |
83 | spin_unlock(&OCFS2_I(inode)->ip_lock); | |
ccd979bd | 84 | |
80c05846 MF |
85 | /* |
86 | * We don't need a cluster lock to test this because once an | |
87 | * inode nlink hits zero, it never goes back. | |
88 | */ | |
89 | if (inode->i_nlink == 0) { | |
a5b8443b TM |
90 | trace_ocfs2_dentry_revalidate_orphaned( |
91 | (unsigned long long)OCFS2_I(inode)->ip_blkno, | |
92 | S_ISDIR(inode->i_mode)); | |
80c05846 | 93 | goto bail; |
ccd979bd MF |
94 | } |
95 | ||
a1b08e75 TM |
96 | /* |
97 | * If the last lookup failed to create dentry lock, let us | |
98 | * redo it. | |
99 | */ | |
100 | if (!dentry->d_fsdata) { | |
a5b8443b TM |
101 | trace_ocfs2_dentry_revalidate_nofsdata( |
102 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
a1b08e75 TM |
103 | goto bail; |
104 | } | |
105 | ||
5e98d492 | 106 | valid: |
ccd979bd MF |
107 | ret = 1; |
108 | ||
109 | bail: | |
a5b8443b | 110 | trace_ocfs2_dentry_revalidate_ret(ret); |
ccd979bd MF |
111 | return ret; |
112 | } | |
113 | ||
80c05846 MF |
114 | static int ocfs2_match_dentry(struct dentry *dentry, |
115 | u64 parent_blkno, | |
116 | int skip_unhashed) | |
117 | { | |
118 | struct inode *parent; | |
119 | ||
120 | /* | |
121 | * ocfs2_lookup() does a d_splice_alias() _before_ attaching | |
122 | * to the lock data, so we skip those here, otherwise | |
123 | * ocfs2_dentry_attach_lock() will get its original dentry | |
124 | * back. | |
125 | */ | |
126 | if (!dentry->d_fsdata) | |
127 | return 0; | |
128 | ||
129 | if (!dentry->d_parent) | |
130 | return 0; | |
131 | ||
132 | if (skip_unhashed && d_unhashed(dentry)) | |
133 | return 0; | |
134 | ||
2b0143b5 | 135 | parent = d_inode(dentry->d_parent); |
80c05846 MF |
136 | /* Negative parent dentry? */ |
137 | if (!parent) | |
138 | return 0; | |
139 | ||
140 | /* Name is in a different directory. */ | |
141 | if (OCFS2_I(parent)->ip_blkno != parent_blkno) | |
142 | return 0; | |
143 | ||
144 | return 1; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Walk the inode alias list, and find a dentry which has a given | |
149 | * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it | |
34d024f8 MF |
150 | * is looking for a dentry_lock reference. The downconvert thread is |
151 | * looking to unhash aliases, so we allow it to skip any that already | |
152 | * have that property. | |
80c05846 MF |
153 | */ |
154 | struct dentry *ocfs2_find_local_alias(struct inode *inode, | |
155 | u64 parent_blkno, | |
156 | int skip_unhashed) | |
157 | { | |
a614a092 | 158 | struct dentry *dentry; |
80c05846 | 159 | |
873feea0 | 160 | spin_lock(&inode->i_lock); |
946e51f2 | 161 | hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) { |
da502956 | 162 | spin_lock(&dentry->d_lock); |
80c05846 | 163 | if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) { |
a5b8443b TM |
164 | trace_ocfs2_find_local_alias(dentry->d_name.len, |
165 | dentry->d_name.name); | |
80c05846 | 166 | |
dc0474be | 167 | dget_dlock(dentry); |
da502956 | 168 | spin_unlock(&dentry->d_lock); |
a614a092 AV |
169 | spin_unlock(&inode->i_lock); |
170 | return dentry; | |
80c05846 | 171 | } |
da502956 | 172 | spin_unlock(&dentry->d_lock); |
80c05846 | 173 | } |
873feea0 | 174 | spin_unlock(&inode->i_lock); |
a614a092 | 175 | return NULL; |
80c05846 MF |
176 | } |
177 | ||
d680efe9 MF |
178 | DEFINE_SPINLOCK(dentry_attach_lock); |
179 | ||
80c05846 MF |
180 | /* |
181 | * Attach this dentry to a cluster lock. | |
182 | * | |
183 | * Dentry locks cover all links in a given directory to a particular | |
184 | * inode. We do this so that ocfs2 can build a lock name which all | |
185 | * nodes in the cluster can agree on at all times. Shoving full names | |
186 | * in the cluster lock won't work due to size restrictions. Covering | |
187 | * links inside of a directory is a good compromise because it still | |
188 | * allows us to use the parent directory lock to synchronize | |
189 | * operations. | |
190 | * | |
191 | * Call this function with the parent dir semaphore and the parent dir | |
192 | * cluster lock held. | |
193 | * | |
194 | * The dir semaphore will protect us from having to worry about | |
195 | * concurrent processes on our node trying to attach a lock at the | |
196 | * same time. | |
197 | * | |
198 | * The dir cluster lock (held at either PR or EX mode) protects us | |
199 | * from unlink and rename on other nodes. | |
200 | * | |
80c05846 MF |
201 | * A dput() can happen asynchronously due to pruning, so we cover |
202 | * attaching and detaching the dentry lock with a | |
203 | * dentry_attach_lock. | |
204 | * | |
205 | * A node which has done lookup on a name retains a protected read | |
206 | * lock until final dput. If the user requests and unlink or rename, | |
207 | * the protected read is upgraded to an exclusive lock. Other nodes | |
208 | * who have seen the dentry will then be informed that they need to | |
209 | * downgrade their lock, which will involve d_delete on the | |
210 | * dentry. This happens in ocfs2_dentry_convert_worker(). | |
211 | */ | |
212 | int ocfs2_dentry_attach_lock(struct dentry *dentry, | |
213 | struct inode *inode, | |
0027dd5b | 214 | u64 parent_blkno) |
80c05846 MF |
215 | { |
216 | int ret; | |
217 | struct dentry *alias; | |
218 | struct ocfs2_dentry_lock *dl = dentry->d_fsdata; | |
219 | ||
a5b8443b TM |
220 | trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name, |
221 | (unsigned long long)parent_blkno, dl); | |
80c05846 MF |
222 | |
223 | /* | |
224 | * Negative dentry. We ignore these for now. | |
225 | * | |
226 | * XXX: Could we can improve ocfs2_dentry_revalidate() by | |
227 | * tracking these? | |
228 | */ | |
229 | if (!inode) | |
230 | return 0; | |
231 | ||
2b0143b5 | 232 | if (d_really_is_negative(dentry) && dentry->d_fsdata) { |
5e98d492 GR |
233 | /* Converting a negative dentry to positive |
234 | Clear dentry->d_fsdata */ | |
235 | dentry->d_fsdata = dl = NULL; | |
236 | } | |
237 | ||
80c05846 MF |
238 | if (dl) { |
239 | mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, | |
a455589f AV |
240 | " \"%pd\": old parent: %llu, new: %llu\n", |
241 | dentry, | |
80c05846 MF |
242 | (unsigned long long)parent_blkno, |
243 | (unsigned long long)dl->dl_parent_blkno); | |
244 | return 0; | |
245 | } | |
246 | ||
247 | alias = ocfs2_find_local_alias(inode, parent_blkno, 0); | |
248 | if (alias) { | |
249 | /* | |
250 | * Great, an alias exists, which means we must have a | |
251 | * dentry lock already. We can just grab the lock off | |
252 | * the alias and add it to the list. | |
253 | * | |
254 | * We're depending here on the fact that this dentry | |
255 | * was found and exists in the dcache and so must have | |
256 | * a reference to the dentry_lock because we can't | |
257 | * race creates. Final dput() cannot happen on it | |
258 | * since we have it pinned, so our reference is safe. | |
259 | */ | |
260 | dl = alias->d_fsdata; | |
0027dd5b | 261 | mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n", |
80c05846 | 262 | (unsigned long long)parent_blkno, |
0027dd5b | 263 | (unsigned long long)OCFS2_I(inode)->ip_blkno); |
80c05846 MF |
264 | |
265 | mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, | |
a455589f AV |
266 | " \"%pd\": old parent: %llu, new: %llu\n", |
267 | dentry, | |
80c05846 MF |
268 | (unsigned long long)parent_blkno, |
269 | (unsigned long long)dl->dl_parent_blkno); | |
270 | ||
a5b8443b TM |
271 | trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name, |
272 | (unsigned long long)parent_blkno, | |
273 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
80c05846 MF |
274 | |
275 | goto out_attach; | |
276 | } | |
277 | ||
278 | /* | |
279 | * There are no other aliases | |
280 | */ | |
281 | dl = kmalloc(sizeof(*dl), GFP_NOFS); | |
282 | if (!dl) { | |
283 | ret = -ENOMEM; | |
284 | mlog_errno(ret); | |
285 | return ret; | |
286 | } | |
287 | ||
288 | dl->dl_count = 0; | |
289 | /* | |
290 | * Does this have to happen below, for all attaches, in case | |
34d024f8 | 291 | * the struct inode gets blown away by the downconvert thread? |
80c05846 MF |
292 | */ |
293 | dl->dl_inode = igrab(inode); | |
294 | dl->dl_parent_blkno = parent_blkno; | |
295 | ocfs2_dentry_lock_res_init(dl, parent_blkno, inode); | |
296 | ||
297 | out_attach: | |
298 | spin_lock(&dentry_attach_lock); | |
be99ca27 WW |
299 | if (unlikely(dentry->d_fsdata && !alias)) { |
300 | /* d_fsdata is set by a racing thread which is doing | |
301 | * the same thing as this thread is doing. Leave the racing | |
302 | * thread going ahead and we return here. | |
303 | */ | |
304 | spin_unlock(&dentry_attach_lock); | |
305 | iput(dl->dl_inode); | |
306 | ocfs2_lock_res_free(&dl->dl_lockres); | |
307 | kfree(dl); | |
308 | return 0; | |
309 | } | |
310 | ||
80c05846 MF |
311 | dentry->d_fsdata = dl; |
312 | dl->dl_count++; | |
313 | spin_unlock(&dentry_attach_lock); | |
314 | ||
80c05846 MF |
315 | /* |
316 | * This actually gets us our PRMODE level lock. From now on, | |
317 | * we'll have a notification if one of these names is | |
318 | * destroyed on another node. | |
319 | */ | |
320 | ret = ocfs2_dentry_lock(dentry, 0); | |
0027dd5b MF |
321 | if (!ret) |
322 | ocfs2_dentry_unlock(dentry, 0); | |
323 | else | |
80c05846 | 324 | mlog_errno(ret); |
80c05846 | 325 | |
a5a0a630 SM |
326 | /* |
327 | * In case of error, manually free the allocation and do the iput(). | |
328 | * We need to do this because error here means no d_instantiate(), | |
329 | * which means iput() will not be called during dput(dentry). | |
330 | */ | |
331 | if (ret < 0 && !alias) { | |
332 | ocfs2_lock_res_free(&dl->dl_lockres); | |
333 | BUG_ON(dl->dl_count != 1); | |
334 | spin_lock(&dentry_attach_lock); | |
335 | dentry->d_fsdata = NULL; | |
336 | spin_unlock(&dentry_attach_lock); | |
337 | kfree(dl); | |
338 | iput(inode); | |
339 | } | |
340 | ||
80c05846 MF |
341 | dput(alias); |
342 | ||
343 | return ret; | |
344 | } | |
345 | ||
346 | /* | |
347 | * ocfs2_dentry_iput() and friends. | |
348 | * | |
349 | * At this point, our particular dentry is detached from the inodes | |
350 | * alias list, so there's no way that the locking code can find it. | |
351 | * | |
352 | * The interesting stuff happens when we determine that our lock needs | |
353 | * to go away because this is the last subdir alias in the | |
354 | * system. This function needs to handle a couple things: | |
355 | * | |
356 | * 1) Synchronizing lock shutdown with the downconvert threads. This | |
357 | * is already handled for us via the lockres release drop function | |
358 | * called in ocfs2_release_dentry_lock() | |
359 | * | |
360 | * 2) A race may occur when we're doing our lock shutdown and | |
361 | * another process wants to create a new dentry lock. Right now we | |
362 | * let them race, which means that for a very short while, this | |
363 | * node might have two locks on a lock resource. This should be a | |
364 | * problem though because one of them is in the process of being | |
365 | * thrown out. | |
366 | */ | |
367 | static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb, | |
368 | struct ocfs2_dentry_lock *dl) | |
369 | { | |
8ed6b237 | 370 | iput(dl->dl_inode); |
80c05846 MF |
371 | ocfs2_simple_drop_lockres(osb, &dl->dl_lockres); |
372 | ocfs2_lock_res_free(&dl->dl_lockres); | |
8ed6b237 | 373 | kfree(dl); |
80c05846 MF |
374 | } |
375 | ||
376 | void ocfs2_dentry_lock_put(struct ocfs2_super *osb, | |
377 | struct ocfs2_dentry_lock *dl) | |
378 | { | |
8ed6b237 | 379 | int unlock = 0; |
80c05846 MF |
380 | |
381 | BUG_ON(dl->dl_count == 0); | |
382 | ||
383 | spin_lock(&dentry_attach_lock); | |
384 | dl->dl_count--; | |
385 | unlock = !dl->dl_count; | |
386 | spin_unlock(&dentry_attach_lock); | |
387 | ||
388 | if (unlock) | |
389 | ocfs2_drop_dentry_lock(osb, dl); | |
390 | } | |
391 | ||
392 | static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode) | |
393 | { | |
394 | struct ocfs2_dentry_lock *dl = dentry->d_fsdata; | |
395 | ||
bccb9dad MF |
396 | if (!dl) { |
397 | /* | |
398 | * No dentry lock is ok if we're disconnected or | |
399 | * unhashed. | |
400 | */ | |
401 | if (!(dentry->d_flags & DCACHE_DISCONNECTED) && | |
402 | !d_unhashed(dentry)) { | |
403 | unsigned long long ino = 0ULL; | |
404 | if (inode) | |
405 | ino = (unsigned long long)OCFS2_I(inode)->ip_blkno; | |
406 | mlog(ML_ERROR, "Dentry is missing cluster lock. " | |
a455589f AV |
407 | "inode: %llu, d_flags: 0x%x, d_name: %pd\n", |
408 | ino, dentry->d_flags, dentry); | |
bccb9dad | 409 | } |
80c05846 | 410 | |
80c05846 | 411 | goto out; |
bccb9dad | 412 | } |
80c05846 | 413 | |
a455589f AV |
414 | mlog_bug_on_msg(dl->dl_count == 0, "dentry: %pd, count: %u\n", |
415 | dentry, dl->dl_count); | |
80c05846 MF |
416 | |
417 | ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl); | |
418 | ||
419 | out: | |
420 | iput(inode); | |
421 | } | |
422 | ||
423 | /* | |
424 | * d_move(), but keep the locks in sync. | |
425 | * | |
426 | * When we are done, "dentry" will have the parent dir and name of | |
427 | * "target", which will be thrown away. | |
428 | * | |
429 | * We manually update the lock of "dentry" if need be. | |
430 | * | |
431 | * "target" doesn't have it's dentry lock touched - we allow the later | |
432 | * dput() to handle this for us. | |
433 | * | |
434 | * This is called during ocfs2_rename(), while holding parent | |
435 | * directory locks. The dentries have already been deleted on other | |
436 | * nodes via ocfs2_remote_dentry_delete(). | |
437 | * | |
3a4fa0a2 | 438 | * Normally, the VFS handles the d_move() for the file system, after |
80c05846 MF |
439 | * the ->rename() callback. OCFS2 wants to handle this internally, so |
440 | * the new lock can be created atomically with respect to the cluster. | |
441 | */ | |
442 | void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target, | |
443 | struct inode *old_dir, struct inode *new_dir) | |
444 | { | |
445 | int ret; | |
446 | struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb); | |
2b0143b5 | 447 | struct inode *inode = d_inode(dentry); |
80c05846 MF |
448 | |
449 | /* | |
450 | * Move within the same directory, so the actual lock info won't | |
451 | * change. | |
452 | * | |
453 | * XXX: Is there any advantage to dropping the lock here? | |
454 | */ | |
455 | if (old_dir == new_dir) | |
1ba9da2f | 456 | goto out_move; |
80c05846 MF |
457 | |
458 | ocfs2_dentry_lock_put(osb, dentry->d_fsdata); | |
459 | ||
460 | dentry->d_fsdata = NULL; | |
0027dd5b | 461 | ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno); |
80c05846 MF |
462 | if (ret) |
463 | mlog_errno(ret); | |
1ba9da2f MF |
464 | |
465 | out_move: | |
466 | d_move(dentry, target); | |
80c05846 MF |
467 | } |
468 | ||
d8fba0ff | 469 | const struct dentry_operations ocfs2_dentry_ops = { |
ccd979bd | 470 | .d_revalidate = ocfs2_dentry_revalidate, |
80c05846 | 471 | .d_iput = ocfs2_dentry_iput, |
ccd979bd | 472 | }; |