1 // SPDX-License-Identifier: GPL-2.0-or-later 1
2 /*
3 * dcache.c
4 *
5 * dentry cache handling code
6 *
7 * Copyright (C) 2002, 2004 Oracle. All right
8 */
9
10 #include <linux/fs.h>
11 #include <linux/types.h>
12 #include <linux/slab.h>
13 #include <linux/namei.h>
14
15 #include <cluster/masklog.h>
16
17 #include "ocfs2.h"
18
19 #include "alloc.h"
20 #include "dcache.h"
21 #include "dlmglue.h"
22 #include "file.h"
23 #include "inode.h"
24 #include "ocfs2_trace.h"
25
26 void ocfs2_dentry_attach_gen(struct dentry *de
27 {
28 unsigned long gen =
29 OCFS2_I(d_inode(dentry->d_pare
30 BUG_ON(d_inode(dentry));
31 dentry->d_fsdata = (void *)gen;
32 }
33
34
35 static int ocfs2_dentry_revalidate(struct dent
36 {
37 struct inode *inode;
38 int ret = 0; /* if all else fails,
39 struct ocfs2_super *osb;
40
41 if (flags & LOOKUP_RCU)
42 return -ECHILD;
43
44 inode = d_inode(dentry);
45 osb = OCFS2_SB(dentry->d_sb);
46
47 trace_ocfs2_dentry_revalidate(dentry,
48 dentry->
49
50 /* For a negative dentry -
51 * check the generation number of the
52 * one stored in the inode.
53 */
54 if (inode == NULL) {
55 unsigned long gen = (unsigned
56 unsigned long pgen;
57 spin_lock(&dentry->d_lock);
58 pgen = OCFS2_I(d_inode(dentry-
59 spin_unlock(&dentry->d_lock);
60 trace_ocfs2_dentry_revalidate_
61
62
63 if (gen != pgen)
64 goto bail;
65 goto valid;
66 }
67
68 BUG_ON(!osb);
69
70 if (inode == osb->root_inode || is_bad
71 goto bail;
72
73 spin_lock(&OCFS2_I(inode)->ip_lock);
74 /* did we or someone else delete this
75 if (OCFS2_I(inode)->ip_flags & OCFS2_I
76 spin_unlock(&OCFS2_I(inode)->i
77 trace_ocfs2_dentry_revalidate_
78 (unsigned long
79 goto bail;
80 }
81 spin_unlock(&OCFS2_I(inode)->ip_lock);
82
83 /*
84 * We don't need a cluster lock to tes
85 * inode nlink hits zero, it never goe
86 */
87 if (inode->i_nlink == 0) {
88 trace_ocfs2_dentry_revalidate_
89 (unsigned long long)OC
90 S_ISDIR(inode->i_mode)
91 goto bail;
92 }
93
94 /*
95 * If the last lookup failed to create
96 * redo it.
97 */
98 if (!dentry->d_fsdata) {
99 trace_ocfs2_dentry_revalidate_
100 (unsigned long
101 goto bail;
102 }
103
104 valid:
105 ret = 1;
106
107 bail:
108 trace_ocfs2_dentry_revalidate_ret(ret)
109 return ret;
110 }
111
112 static int ocfs2_match_dentry(struct dentry *d
113 u64 parent_blkno
114 int skip_unhashe
115 {
116 struct inode *parent;
117
118 /*
119 * ocfs2_lookup() does a d_splice_alia
120 * to the lock data, so we skip those
121 * ocfs2_dentry_attach_lock() will get
122 * back.
123 */
124 if (!dentry->d_fsdata)
125 return 0;
126
127 if (skip_unhashed && d_unhashed(dentry
128 return 0;
129
130 parent = d_inode(dentry->d_parent);
131 /* Name is in a different directory. *
132 if (OCFS2_I(parent)->ip_blkno != paren
133 return 0;
134
135 return 1;
136 }
137
138 /*
139 * Walk the inode alias list, and find a dentr
140 * parent. ocfs2_dentry_attach_lock() wants to
141 * is looking for a dentry_lock reference. The
142 * looking to unhash aliases, so we allow it t
143 * have that property.
144 */
145 struct dentry *ocfs2_find_local_alias(struct i
146 u64 pare
147 int skip
148 {
149 struct dentry *dentry;
150
151 spin_lock(&inode->i_lock);
152 hlist_for_each_entry(dentry, &inode->i
153 spin_lock(&dentry->d_lock);
154 if (ocfs2_match_dentry(dentry,
155 trace_ocfs2_find_local
156
157
158 dget_dlock(dentry);
159 spin_unlock(&dentry->d
160 spin_unlock(&inode->i_
161 return dentry;
162 }
163 spin_unlock(&dentry->d_lock);
164 }
165 spin_unlock(&inode->i_lock);
166 return NULL;
167 }
168
169 DEFINE_SPINLOCK(dentry_attach_lock);
170
171 /*
172 * Attach this dentry to a cluster lock.
173 *
174 * Dentry locks cover all links in a given dir
175 * inode. We do this so that ocfs2 can build a
176 * nodes in the cluster can agree on at all ti
177 * in the cluster lock won't work due to size
178 * links inside of a directory is a good compr
179 * allows us to use the parent directory lock
180 * operations.
181 *
182 * Call this function with the parent dir sema
183 * cluster lock held.
184 *
185 * The dir semaphore will protect us from havi
186 * concurrent processes on our node trying to
187 * same time.
188 *
189 * The dir cluster lock (held at either PR or
190 * from unlink and rename on other nodes.
191 *
192 * A dput() can happen asynchronously due to p
193 * attaching and detaching the dentry lock wit
194 * dentry_attach_lock.
195 *
196 * A node which has done lookup on a name reta
197 * lock until final dput. If the user requests
198 * the protected read is upgraded to an exclus
199 * who have seen the dentry will then be infor
200 * downgrade their lock, which will involve d_
201 * dentry. This happens in ocfs2_dentry_conver
202 */
203 int ocfs2_dentry_attach_lock(struct dentry *de
204 struct inode *ino
205 u64 parent_blkno)
206 {
207 int ret;
208 struct dentry *alias;
209 struct ocfs2_dentry_lock *dl = dentry-
210
211 trace_ocfs2_dentry_attach_lock(dentry-
212 (unsign
213
214 /*
215 * Negative dentry. We ignore these fo
216 *
217 * XXX: Could we can improve ocfs2_den
218 * tracking these?
219 */
220 if (!inode)
221 return 0;
222
223 if (d_really_is_negative(dentry) && de
224 /* Converting a negative dentr
225 Clear dentry->d_fsdata */
226 dentry->d_fsdata = dl = NULL;
227 }
228
229 if (dl) {
230 mlog_bug_on_msg(dl->dl_parent_
231 " \"%pd\": old
232 dentry,
233 (unsigned long
234 (unsigned long
235 return 0;
236 }
237
238 alias = ocfs2_find_local_alias(inode,
239 if (alias) {
240 /*
241 * Great, an alias exists, whi
242 * dentry lock already. We can
243 * the alias and add it to the
244 *
245 * We're depending here on the
246 * was found and exists in the
247 * a reference to the dentry_l
248 * race creates. Final dput()
249 * since we have it pinned, so
250 */
251 dl = alias->d_fsdata;
252 mlog_bug_on_msg(!dl, "parent %
253 (unsigned long
254 (unsigned long
255
256 mlog_bug_on_msg(dl->dl_parent_
257 " \"%pd\": old
258 dentry,
259 (unsigned long
260 (unsigned long
261
262 trace_ocfs2_dentry_attach_lock
263 (unsigned long
264 (unsigned long
265
266 goto out_attach;
267 }
268
269 /*
270 * There are no other aliases
271 */
272 dl = kmalloc(sizeof(*dl), GFP_NOFS);
273 if (!dl) {
274 ret = -ENOMEM;
275 mlog_errno(ret);
276 return ret;
277 }
278
279 dl->dl_count = 0;
280 /*
281 * Does this have to happen below, for
282 * the struct inode gets blown away by
283 */
284 dl->dl_inode = igrab(inode);
285 dl->dl_parent_blkno = parent_blkno;
286 ocfs2_dentry_lock_res_init(dl, parent_
287
288 out_attach:
289 spin_lock(&dentry_attach_lock);
290 if (unlikely(dentry->d_fsdata && !alia
291 /* d_fsdata is set by a racing
292 * the same thing as this thre
293 * thread going ahead and we r
294 */
295 spin_unlock(&dentry_attach_loc
296 iput(dl->dl_inode);
297 ocfs2_lock_res_free(&dl->dl_lo
298 kfree(dl);
299 return 0;
300 }
301
302 dentry->d_fsdata = dl;
303 dl->dl_count++;
304 spin_unlock(&dentry_attach_lock);
305
306 /*
307 * This actually gets us our PRMODE le
308 * we'll have a notification if one of
309 * destroyed on another node.
310 */
311 ret = ocfs2_dentry_lock(dentry, 0);
312 if (!ret)
313 ocfs2_dentry_unlock(dentry, 0)
314 else
315 mlog_errno(ret);
316
317 /*
318 * In case of error, manually free the
319 * We need to do this because error he
320 * which means iput() will not be call
321 */
322 if (ret < 0 && !alias) {
323 ocfs2_lock_res_free(&dl->dl_lo
324 BUG_ON(dl->dl_count != 1);
325 spin_lock(&dentry_attach_lock)
326 dentry->d_fsdata = NULL;
327 spin_unlock(&dentry_attach_loc
328 kfree(dl);
329 iput(inode);
330 }
331
332 dput(alias);
333
334 return ret;
335 }
336
337 /*
338 * ocfs2_dentry_iput() and friends.
339 *
340 * At this point, our particular dentry is det
341 * alias list, so there's no way that the lock
342 *
343 * The interesting stuff happens when we deter
344 * to go away because this is the last subdir
345 * system. This function needs to handle a cou
346 *
347 * 1) Synchronizing lock shutdown with the dow
348 * is already handled for us via the lockre
349 * called in ocfs2_release_dentry_lock()
350 *
351 * 2) A race may occur when we're doing our lo
352 * another process wants to create a new de
353 * let them race, which means that for a ve
354 * node might have two locks on a lock reso
355 * problem though because one of them is in
356 * thrown out.
357 */
358 static void ocfs2_drop_dentry_lock(struct ocfs
359 struct ocfs
360 {
361 iput(dl->dl_inode);
362 ocfs2_simple_drop_lockres(osb, &dl->dl
363 ocfs2_lock_res_free(&dl->dl_lockres);
364 kfree(dl);
365 }
366
367 void ocfs2_dentry_lock_put(struct ocfs2_super
368 struct ocfs2_dentry
369 {
370 int unlock = 0;
371
372 BUG_ON(dl->dl_count == 0);
373
374 spin_lock(&dentry_attach_lock);
375 dl->dl_count--;
376 unlock = !dl->dl_count;
377 spin_unlock(&dentry_attach_lock);
378
379 if (unlock)
380 ocfs2_drop_dentry_lock(osb, dl
381 }
382
383 static void ocfs2_dentry_iput(struct dentry *d
384 {
385 struct ocfs2_dentry_lock *dl = dentry-
386
387 if (!dl) {
388 /*
389 * No dentry lock is ok if we'
390 * unhashed.
391 */
392 if (!(dentry->d_flags & DCACHE
393 !d_unhashed(dentry)) {
394 unsigned long long ino
395 if (inode)
396 ino = (unsigne
397 mlog(ML_ERROR, "Dentry
398 "inode: %llu, d_f
399 ino, dentry->d_fl
400 }
401
402 goto out;
403 }
404
405 mlog_bug_on_msg(dl->dl_count == 0, "de
406 dentry, dl->dl_count);
407
408 ocfs2_dentry_lock_put(OCFS2_SB(dentry-
409
410 out:
411 iput(inode);
412 }
413
414 /*
415 * d_move(), but keep the locks in sync.
416 *
417 * When we are done, "dentry" will have the pa
418 * "target", which will be thrown away.
419 *
420 * We manually update the lock of "dentry" if
421 *
422 * "target" doesn't have it's dentry lock touc
423 * dput() to handle this for us.
424 *
425 * This is called during ocfs2_rename(), while
426 * directory locks. The dentries have already
427 * nodes via ocfs2_remote_dentry_delete().
428 *
429 * Normally, the VFS handles the d_move() for
430 * the ->rename() callback. OCFS2 wants to han
431 * the new lock can be created atomically with
432 */
433 void ocfs2_dentry_move(struct dentry *dentry,
434 struct inode *old_dir,
435 {
436 int ret;
437 struct ocfs2_super *osb = OCFS2_SB(old
438 struct inode *inode = d_inode(dentry);
439
440 /*
441 * Move within the same directory, so
442 * change.
443 *
444 * XXX: Is there any advantage to drop
445 */
446 if (old_dir == new_dir)
447 goto out_move;
448
449 ocfs2_dentry_lock_put(osb, dentry->d_f
450
451 dentry->d_fsdata = NULL;
452 ret = ocfs2_dentry_attach_lock(dentry,
453 if (ret)
454 mlog_errno(ret);
455
456 out_move:
457 d_move(dentry, target);
458 }
459
460 const struct dentry_operations ocfs2_dentry_op
461 .d_revalidate = ocfs2_dentry
462 .d_iput = ocfs2_dentry
463 };
464
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