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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fa60ce2c | 2 | /* |
ccd979bd MF |
3 | * dcache.c |
4 | * | |
5 | * dentry cache handling code | |
6 | * | |
7 | * Copyright (C) 2002, 2004 Oracle. All rights reserved. | |
ccd979bd MF |
8 | */ |
9 | ||
10 | #include <linux/fs.h> | |
11 | #include <linux/types.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/namei.h> | |
14 | ||
ccd979bd MF |
15 | #include <cluster/masklog.h> |
16 | ||
17 | #include "ocfs2.h" | |
18 | ||
19 | #include "alloc.h" | |
20 | #include "dcache.h" | |
80c05846 | 21 | #include "dlmglue.h" |
ccd979bd MF |
22 | #include "file.h" |
23 | #include "inode.h" | |
a5b8443b | 24 | #include "ocfs2_trace.h" |
ccd979bd | 25 | |
5e98d492 GR |
26 | void ocfs2_dentry_attach_gen(struct dentry *dentry) |
27 | { | |
28 | unsigned long gen = | |
2b0143b5 DH |
29 | OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen; |
30 | BUG_ON(d_inode(dentry)); | |
5e98d492 GR |
31 | dentry->d_fsdata = (void *)gen; |
32 | } | |
33 | ||
80c05846 | 34 | |
0b728e19 | 35 | static int ocfs2_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
ccd979bd | 36 | { |
34286d66 | 37 | struct inode *inode; |
ccd979bd | 38 | int ret = 0; /* if all else fails, just return false */ |
34286d66 NP |
39 | struct ocfs2_super *osb; |
40 | ||
0b728e19 | 41 | if (flags & LOOKUP_RCU) |
34286d66 NP |
42 | return -ECHILD; |
43 | ||
2b0143b5 | 44 | inode = d_inode(dentry); |
34286d66 | 45 | osb = OCFS2_SB(dentry->d_sb); |
ccd979bd | 46 | |
a5b8443b TM |
47 | trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len, |
48 | dentry->d_name.name); | |
ccd979bd | 49 | |
5e98d492 GR |
50 | /* For a negative dentry - |
51 | * check the generation number of the parent and compare with the | |
52 | * one stored in the inode. | |
53 | */ | |
ccd979bd | 54 | if (inode == NULL) { |
5e98d492 | 55 | unsigned long gen = (unsigned long) dentry->d_fsdata; |
7b9a2378 AV |
56 | unsigned long pgen; |
57 | spin_lock(&dentry->d_lock); | |
2b0143b5 | 58 | pgen = OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen; |
7b9a2378 | 59 | spin_unlock(&dentry->d_lock); |
a5b8443b TM |
60 | trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len, |
61 | dentry->d_name.name, | |
62 | pgen, gen); | |
5e98d492 GR |
63 | if (gen != pgen) |
64 | goto bail; | |
65 | goto valid; | |
ccd979bd MF |
66 | } |
67 | ||
ccd979bd MF |
68 | BUG_ON(!osb); |
69 | ||
80c05846 MF |
70 | if (inode == osb->root_inode || is_bad_inode(inode)) |
71 | goto bail; | |
72 | ||
73 | spin_lock(&OCFS2_I(inode)->ip_lock); | |
74 | /* did we or someone else delete this inode? */ | |
75 | if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) { | |
ccd979bd | 76 | spin_unlock(&OCFS2_I(inode)->ip_lock); |
a5b8443b TM |
77 | trace_ocfs2_dentry_revalidate_delete( |
78 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
80c05846 MF |
79 | goto bail; |
80 | } | |
81 | spin_unlock(&OCFS2_I(inode)->ip_lock); | |
ccd979bd | 82 | |
80c05846 MF |
83 | /* |
84 | * We don't need a cluster lock to test this because once an | |
85 | * inode nlink hits zero, it never goes back. | |
86 | */ | |
87 | if (inode->i_nlink == 0) { | |
a5b8443b TM |
88 | trace_ocfs2_dentry_revalidate_orphaned( |
89 | (unsigned long long)OCFS2_I(inode)->ip_blkno, | |
90 | S_ISDIR(inode->i_mode)); | |
80c05846 | 91 | goto bail; |
ccd979bd MF |
92 | } |
93 | ||
a1b08e75 TM |
94 | /* |
95 | * If the last lookup failed to create dentry lock, let us | |
96 | * redo it. | |
97 | */ | |
98 | if (!dentry->d_fsdata) { | |
a5b8443b TM |
99 | trace_ocfs2_dentry_revalidate_nofsdata( |
100 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
a1b08e75 TM |
101 | goto bail; |
102 | } | |
103 | ||
5e98d492 | 104 | valid: |
ccd979bd MF |
105 | ret = 1; |
106 | ||
107 | bail: | |
a5b8443b | 108 | trace_ocfs2_dentry_revalidate_ret(ret); |
ccd979bd MF |
109 | return ret; |
110 | } | |
111 | ||
80c05846 MF |
112 | static int ocfs2_match_dentry(struct dentry *dentry, |
113 | u64 parent_blkno, | |
114 | int skip_unhashed) | |
115 | { | |
116 | struct inode *parent; | |
117 | ||
118 | /* | |
119 | * ocfs2_lookup() does a d_splice_alias() _before_ attaching | |
120 | * to the lock data, so we skip those here, otherwise | |
121 | * ocfs2_dentry_attach_lock() will get its original dentry | |
122 | * back. | |
123 | */ | |
124 | if (!dentry->d_fsdata) | |
125 | return 0; | |
126 | ||
127 | if (!dentry->d_parent) | |
128 | return 0; | |
129 | ||
130 | if (skip_unhashed && d_unhashed(dentry)) | |
131 | return 0; | |
132 | ||
2b0143b5 | 133 | parent = d_inode(dentry->d_parent); |
80c05846 MF |
134 | /* Negative parent dentry? */ |
135 | if (!parent) | |
136 | return 0; | |
137 | ||
138 | /* Name is in a different directory. */ | |
139 | if (OCFS2_I(parent)->ip_blkno != parent_blkno) | |
140 | return 0; | |
141 | ||
142 | return 1; | |
143 | } | |
144 | ||
145 | /* | |
146 | * Walk the inode alias list, and find a dentry which has a given | |
147 | * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it | |
34d024f8 MF |
148 | * is looking for a dentry_lock reference. The downconvert thread is |
149 | * looking to unhash aliases, so we allow it to skip any that already | |
150 | * have that property. | |
80c05846 MF |
151 | */ |
152 | struct dentry *ocfs2_find_local_alias(struct inode *inode, | |
153 | u64 parent_blkno, | |
154 | int skip_unhashed) | |
155 | { | |
a614a092 | 156 | struct dentry *dentry; |
80c05846 | 157 | |
873feea0 | 158 | spin_lock(&inode->i_lock); |
946e51f2 | 159 | hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) { |
da502956 | 160 | spin_lock(&dentry->d_lock); |
80c05846 | 161 | if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) { |
a5b8443b TM |
162 | trace_ocfs2_find_local_alias(dentry->d_name.len, |
163 | dentry->d_name.name); | |
80c05846 | 164 | |
dc0474be | 165 | dget_dlock(dentry); |
da502956 | 166 | spin_unlock(&dentry->d_lock); |
a614a092 AV |
167 | spin_unlock(&inode->i_lock); |
168 | return dentry; | |
80c05846 | 169 | } |
da502956 | 170 | spin_unlock(&dentry->d_lock); |
80c05846 | 171 | } |
873feea0 | 172 | spin_unlock(&inode->i_lock); |
a614a092 | 173 | return NULL; |
80c05846 MF |
174 | } |
175 | ||
d680efe9 MF |
176 | DEFINE_SPINLOCK(dentry_attach_lock); |
177 | ||
80c05846 MF |
178 | /* |
179 | * Attach this dentry to a cluster lock. | |
180 | * | |
181 | * Dentry locks cover all links in a given directory to a particular | |
182 | * inode. We do this so that ocfs2 can build a lock name which all | |
183 | * nodes in the cluster can agree on at all times. Shoving full names | |
184 | * in the cluster lock won't work due to size restrictions. Covering | |
185 | * links inside of a directory is a good compromise because it still | |
186 | * allows us to use the parent directory lock to synchronize | |
187 | * operations. | |
188 | * | |
189 | * Call this function with the parent dir semaphore and the parent dir | |
190 | * cluster lock held. | |
191 | * | |
192 | * The dir semaphore will protect us from having to worry about | |
193 | * concurrent processes on our node trying to attach a lock at the | |
194 | * same time. | |
195 | * | |
196 | * The dir cluster lock (held at either PR or EX mode) protects us | |
197 | * from unlink and rename on other nodes. | |
198 | * | |
80c05846 MF |
199 | * A dput() can happen asynchronously due to pruning, so we cover |
200 | * attaching and detaching the dentry lock with a | |
201 | * dentry_attach_lock. | |
202 | * | |
203 | * A node which has done lookup on a name retains a protected read | |
204 | * lock until final dput. If the user requests and unlink or rename, | |
205 | * the protected read is upgraded to an exclusive lock. Other nodes | |
206 | * who have seen the dentry will then be informed that they need to | |
207 | * downgrade their lock, which will involve d_delete on the | |
208 | * dentry. This happens in ocfs2_dentry_convert_worker(). | |
209 | */ | |
210 | int ocfs2_dentry_attach_lock(struct dentry *dentry, | |
211 | struct inode *inode, | |
0027dd5b | 212 | u64 parent_blkno) |
80c05846 MF |
213 | { |
214 | int ret; | |
215 | struct dentry *alias; | |
216 | struct ocfs2_dentry_lock *dl = dentry->d_fsdata; | |
217 | ||
a5b8443b TM |
218 | trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name, |
219 | (unsigned long long)parent_blkno, dl); | |
80c05846 MF |
220 | |
221 | /* | |
222 | * Negative dentry. We ignore these for now. | |
223 | * | |
224 | * XXX: Could we can improve ocfs2_dentry_revalidate() by | |
225 | * tracking these? | |
226 | */ | |
227 | if (!inode) | |
228 | return 0; | |
229 | ||
2b0143b5 | 230 | if (d_really_is_negative(dentry) && dentry->d_fsdata) { |
5e98d492 GR |
231 | /* Converting a negative dentry to positive |
232 | Clear dentry->d_fsdata */ | |
233 | dentry->d_fsdata = dl = NULL; | |
234 | } | |
235 | ||
80c05846 MF |
236 | if (dl) { |
237 | mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, | |
a455589f AV |
238 | " \"%pd\": old parent: %llu, new: %llu\n", |
239 | dentry, | |
80c05846 MF |
240 | (unsigned long long)parent_blkno, |
241 | (unsigned long long)dl->dl_parent_blkno); | |
242 | return 0; | |
243 | } | |
244 | ||
245 | alias = ocfs2_find_local_alias(inode, parent_blkno, 0); | |
246 | if (alias) { | |
247 | /* | |
248 | * Great, an alias exists, which means we must have a | |
249 | * dentry lock already. We can just grab the lock off | |
250 | * the alias and add it to the list. | |
251 | * | |
252 | * We're depending here on the fact that this dentry | |
253 | * was found and exists in the dcache and so must have | |
254 | * a reference to the dentry_lock because we can't | |
255 | * race creates. Final dput() cannot happen on it | |
256 | * since we have it pinned, so our reference is safe. | |
257 | */ | |
258 | dl = alias->d_fsdata; | |
0027dd5b | 259 | mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n", |
80c05846 | 260 | (unsigned long long)parent_blkno, |
0027dd5b | 261 | (unsigned long long)OCFS2_I(inode)->ip_blkno); |
80c05846 MF |
262 | |
263 | mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, | |
a455589f AV |
264 | " \"%pd\": old parent: %llu, new: %llu\n", |
265 | dentry, | |
80c05846 MF |
266 | (unsigned long long)parent_blkno, |
267 | (unsigned long long)dl->dl_parent_blkno); | |
268 | ||
a5b8443b TM |
269 | trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name, |
270 | (unsigned long long)parent_blkno, | |
271 | (unsigned long long)OCFS2_I(inode)->ip_blkno); | |
80c05846 MF |
272 | |
273 | goto out_attach; | |
274 | } | |
275 | ||
276 | /* | |
277 | * There are no other aliases | |
278 | */ | |
279 | dl = kmalloc(sizeof(*dl), GFP_NOFS); | |
280 | if (!dl) { | |
281 | ret = -ENOMEM; | |
282 | mlog_errno(ret); | |
283 | return ret; | |
284 | } | |
285 | ||
286 | dl->dl_count = 0; | |
287 | /* | |
288 | * Does this have to happen below, for all attaches, in case | |
34d024f8 | 289 | * the struct inode gets blown away by the downconvert thread? |
80c05846 MF |
290 | */ |
291 | dl->dl_inode = igrab(inode); | |
292 | dl->dl_parent_blkno = parent_blkno; | |
293 | ocfs2_dentry_lock_res_init(dl, parent_blkno, inode); | |
294 | ||
295 | out_attach: | |
296 | spin_lock(&dentry_attach_lock); | |
be99ca27 WW |
297 | if (unlikely(dentry->d_fsdata && !alias)) { |
298 | /* d_fsdata is set by a racing thread which is doing | |
299 | * the same thing as this thread is doing. Leave the racing | |
300 | * thread going ahead and we return here. | |
301 | */ | |
302 | spin_unlock(&dentry_attach_lock); | |
303 | iput(dl->dl_inode); | |
304 | ocfs2_lock_res_free(&dl->dl_lockres); | |
305 | kfree(dl); | |
306 | return 0; | |
307 | } | |
308 | ||
80c05846 MF |
309 | dentry->d_fsdata = dl; |
310 | dl->dl_count++; | |
311 | spin_unlock(&dentry_attach_lock); | |
312 | ||
80c05846 MF |
313 | /* |
314 | * This actually gets us our PRMODE level lock. From now on, | |
315 | * we'll have a notification if one of these names is | |
316 | * destroyed on another node. | |
317 | */ | |
318 | ret = ocfs2_dentry_lock(dentry, 0); | |
0027dd5b MF |
319 | if (!ret) |
320 | ocfs2_dentry_unlock(dentry, 0); | |
321 | else | |
80c05846 | 322 | mlog_errno(ret); |
80c05846 | 323 | |
a5a0a630 SM |
324 | /* |
325 | * In case of error, manually free the allocation and do the iput(). | |
326 | * We need to do this because error here means no d_instantiate(), | |
327 | * which means iput() will not be called during dput(dentry). | |
328 | */ | |
329 | if (ret < 0 && !alias) { | |
330 | ocfs2_lock_res_free(&dl->dl_lockres); | |
331 | BUG_ON(dl->dl_count != 1); | |
332 | spin_lock(&dentry_attach_lock); | |
333 | dentry->d_fsdata = NULL; | |
334 | spin_unlock(&dentry_attach_lock); | |
335 | kfree(dl); | |
336 | iput(inode); | |
337 | } | |
338 | ||
80c05846 MF |
339 | dput(alias); |
340 | ||
341 | return ret; | |
342 | } | |
343 | ||
344 | /* | |
345 | * ocfs2_dentry_iput() and friends. | |
346 | * | |
347 | * At this point, our particular dentry is detached from the inodes | |
348 | * alias list, so there's no way that the locking code can find it. | |
349 | * | |
350 | * The interesting stuff happens when we determine that our lock needs | |
351 | * to go away because this is the last subdir alias in the | |
352 | * system. This function needs to handle a couple things: | |
353 | * | |
354 | * 1) Synchronizing lock shutdown with the downconvert threads. This | |
355 | * is already handled for us via the lockres release drop function | |
356 | * called in ocfs2_release_dentry_lock() | |
357 | * | |
358 | * 2) A race may occur when we're doing our lock shutdown and | |
359 | * another process wants to create a new dentry lock. Right now we | |
360 | * let them race, which means that for a very short while, this | |
361 | * node might have two locks on a lock resource. This should be a | |
362 | * problem though because one of them is in the process of being | |
363 | * thrown out. | |
364 | */ | |
365 | static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb, | |
366 | struct ocfs2_dentry_lock *dl) | |
367 | { | |
8ed6b237 | 368 | iput(dl->dl_inode); |
80c05846 MF |
369 | ocfs2_simple_drop_lockres(osb, &dl->dl_lockres); |
370 | ocfs2_lock_res_free(&dl->dl_lockres); | |
8ed6b237 | 371 | kfree(dl); |
80c05846 MF |
372 | } |
373 | ||
374 | void ocfs2_dentry_lock_put(struct ocfs2_super *osb, | |
375 | struct ocfs2_dentry_lock *dl) | |
376 | { | |
8ed6b237 | 377 | int unlock = 0; |
80c05846 MF |
378 | |
379 | BUG_ON(dl->dl_count == 0); | |
380 | ||
381 | spin_lock(&dentry_attach_lock); | |
382 | dl->dl_count--; | |
383 | unlock = !dl->dl_count; | |
384 | spin_unlock(&dentry_attach_lock); | |
385 | ||
386 | if (unlock) | |
387 | ocfs2_drop_dentry_lock(osb, dl); | |
388 | } | |
389 | ||
390 | static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode) | |
391 | { | |
392 | struct ocfs2_dentry_lock *dl = dentry->d_fsdata; | |
393 | ||
bccb9dad MF |
394 | if (!dl) { |
395 | /* | |
396 | * No dentry lock is ok if we're disconnected or | |
397 | * unhashed. | |
398 | */ | |
399 | if (!(dentry->d_flags & DCACHE_DISCONNECTED) && | |
400 | !d_unhashed(dentry)) { | |
401 | unsigned long long ino = 0ULL; | |
402 | if (inode) | |
403 | ino = (unsigned long long)OCFS2_I(inode)->ip_blkno; | |
404 | mlog(ML_ERROR, "Dentry is missing cluster lock. " | |
a455589f AV |
405 | "inode: %llu, d_flags: 0x%x, d_name: %pd\n", |
406 | ino, dentry->d_flags, dentry); | |
bccb9dad | 407 | } |
80c05846 | 408 | |
80c05846 | 409 | goto out; |
bccb9dad | 410 | } |
80c05846 | 411 | |
a455589f AV |
412 | mlog_bug_on_msg(dl->dl_count == 0, "dentry: %pd, count: %u\n", |
413 | dentry, dl->dl_count); | |
80c05846 MF |
414 | |
415 | ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl); | |
416 | ||
417 | out: | |
418 | iput(inode); | |
419 | } | |
420 | ||
421 | /* | |
422 | * d_move(), but keep the locks in sync. | |
423 | * | |
424 | * When we are done, "dentry" will have the parent dir and name of | |
425 | * "target", which will be thrown away. | |
426 | * | |
427 | * We manually update the lock of "dentry" if need be. | |
428 | * | |
429 | * "target" doesn't have it's dentry lock touched - we allow the later | |
430 | * dput() to handle this for us. | |
431 | * | |
432 | * This is called during ocfs2_rename(), while holding parent | |
433 | * directory locks. The dentries have already been deleted on other | |
434 | * nodes via ocfs2_remote_dentry_delete(). | |
435 | * | |
3a4fa0a2 | 436 | * Normally, the VFS handles the d_move() for the file system, after |
80c05846 MF |
437 | * the ->rename() callback. OCFS2 wants to handle this internally, so |
438 | * the new lock can be created atomically with respect to the cluster. | |
439 | */ | |
440 | void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target, | |
441 | struct inode *old_dir, struct inode *new_dir) | |
442 | { | |
443 | int ret; | |
444 | struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb); | |
2b0143b5 | 445 | struct inode *inode = d_inode(dentry); |
80c05846 MF |
446 | |
447 | /* | |
448 | * Move within the same directory, so the actual lock info won't | |
449 | * change. | |
450 | * | |
451 | * XXX: Is there any advantage to dropping the lock here? | |
452 | */ | |
453 | if (old_dir == new_dir) | |
1ba9da2f | 454 | goto out_move; |
80c05846 MF |
455 | |
456 | ocfs2_dentry_lock_put(osb, dentry->d_fsdata); | |
457 | ||
458 | dentry->d_fsdata = NULL; | |
0027dd5b | 459 | ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno); |
80c05846 MF |
460 | if (ret) |
461 | mlog_errno(ret); | |
1ba9da2f MF |
462 | |
463 | out_move: | |
464 | d_move(dentry, target); | |
80c05846 MF |
465 | } |
466 | ||
d8fba0ff | 467 | const struct dentry_operations ocfs2_dentry_ops = { |
ccd979bd | 468 | .d_revalidate = ocfs2_dentry_revalidate, |
80c05846 | 469 | .d_iput = ocfs2_dentry_iput, |
ccd979bd | 470 | }; |