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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * dcache.c
4 *
5 * dentry cache handling code
6 *
7 * Copyright (C) 2002, 2004 Oracle. All rights reserved.
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
26void ocfs2_dentry_attach_gen(struct dentry *dentry)
27{
28 unsigned long gen =
29 OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
30 BUG_ON(d_inode(dentry));
31 dentry->d_fsdata = (void *)gen;
32}
33
34
35static int ocfs2_dentry_revalidate(struct dentry *dentry, unsigned int flags)
36{
37 struct inode *inode;
38 int ret = 0; /* if all else fails, just return false */
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, dentry->d_name.len,
48 dentry->d_name.name);
49
50 /* For a negative dentry -
51 * check the generation number of the parent and compare with the
52 * one stored in the inode.
53 */
54 if (inode == NULL) {
55 unsigned long gen = (unsigned long) dentry->d_fsdata;
56 unsigned long pgen;
57 spin_lock(&dentry->d_lock);
58 pgen = OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
59 spin_unlock(&dentry->d_lock);
60 trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len,
61 dentry->d_name.name,
62 pgen, gen);
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_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) {
76 spin_unlock(&OCFS2_I(inode)->ip_lock);
77 trace_ocfs2_dentry_revalidate_delete(
78 (unsigned long long)OCFS2_I(inode)->ip_blkno);
79 goto bail;
80 }
81 spin_unlock(&OCFS2_I(inode)->ip_lock);
82
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) {
88 trace_ocfs2_dentry_revalidate_orphaned(
89 (unsigned long long)OCFS2_I(inode)->ip_blkno,
90 S_ISDIR(inode->i_mode));
91 goto bail;
92 }
93
94 /*
95 * If the last lookup failed to create dentry lock, let us
96 * redo it.
97 */
98 if (!dentry->d_fsdata) {
99 trace_ocfs2_dentry_revalidate_nofsdata(
100 (unsigned long long)OCFS2_I(inode)->ip_blkno);
101 goto bail;
102 }
103
104valid:
105 ret = 1;
106
107bail:
108 trace_ocfs2_dentry_revalidate_ret(ret);
109 return ret;
110}
111
112static 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 (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 != parent_blkno)
133 return 0;
134
135 return 1;
136}
137
138/*
139 * Walk the inode alias list, and find a dentry which has a given
140 * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
141 * is looking for a dentry_lock reference. The downconvert thread is
142 * looking to unhash aliases, so we allow it to skip any that already
143 * have that property.
144 */
145struct dentry *ocfs2_find_local_alias(struct inode *inode,
146 u64 parent_blkno,
147 int skip_unhashed)
148{
149 struct dentry *dentry;
150
151 spin_lock(&inode->i_lock);
152 hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
153 spin_lock(&dentry->d_lock);
154 if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
155 trace_ocfs2_find_local_alias(dentry->d_name.len,
156 dentry->d_name.name);
157
158 dget_dlock(dentry);
159 spin_unlock(&dentry->d_lock);
160 spin_unlock(&inode->i_lock);
161 return dentry;
162 }
163 spin_unlock(&dentry->d_lock);
164 }
165 spin_unlock(&inode->i_lock);
166 return NULL;
167}
168
169DEFINE_SPINLOCK(dentry_attach_lock);
170
171/*
172 * Attach this dentry to a cluster lock.
173 *
174 * Dentry locks cover all links in a given directory to a particular
175 * inode. We do this so that ocfs2 can build a lock name which all
176 * nodes in the cluster can agree on at all times. Shoving full names
177 * in the cluster lock won't work due to size restrictions. Covering
178 * links inside of a directory is a good compromise because it still
179 * allows us to use the parent directory lock to synchronize
180 * operations.
181 *
182 * Call this function with the parent dir semaphore and the parent dir
183 * cluster lock held.
184 *
185 * The dir semaphore will protect us from having to worry about
186 * concurrent processes on our node trying to attach a lock at the
187 * same time.
188 *
189 * The dir cluster lock (held at either PR or EX mode) protects us
190 * from unlink and rename on other nodes.
191 *
192 * A dput() can happen asynchronously due to pruning, so we cover
193 * attaching and detaching the dentry lock with a
194 * dentry_attach_lock.
195 *
196 * A node which has done lookup on a name retains a protected read
197 * lock until final dput. If the user requests and unlink or rename,
198 * the protected read is upgraded to an exclusive lock. Other nodes
199 * who have seen the dentry will then be informed that they need to
200 * downgrade their lock, which will involve d_delete on the
201 * dentry. This happens in ocfs2_dentry_convert_worker().
202 */
203int ocfs2_dentry_attach_lock(struct dentry *dentry,
204 struct inode *inode,
205 u64 parent_blkno)
206{
207 int ret;
208 struct dentry *alias;
209 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
210
211 trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name,
212 (unsigned long long)parent_blkno, dl);
213
214 /*
215 * Negative dentry. We ignore these for now.
216 *
217 * XXX: Could we can improve ocfs2_dentry_revalidate() by
218 * tracking these?
219 */
220 if (!inode)
221 return 0;
222
223 if (d_really_is_negative(dentry) && dentry->d_fsdata) {
224 /* Converting a negative dentry to positive
225 Clear dentry->d_fsdata */
226 dentry->d_fsdata = dl = NULL;
227 }
228
229 if (dl) {
230 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
231 " \"%pd\": old parent: %llu, new: %llu\n",
232 dentry,
233 (unsigned long long)parent_blkno,
234 (unsigned long long)dl->dl_parent_blkno);
235 return 0;
236 }
237
238 alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
239 if (alias) {
240 /*
241 * Great, an alias exists, which means we must have a
242 * dentry lock already. We can just grab the lock off
243 * the alias and add it to the list.
244 *
245 * We're depending here on the fact that this dentry
246 * was found and exists in the dcache and so must have
247 * a reference to the dentry_lock because we can't
248 * race creates. Final dput() cannot happen on it
249 * since we have it pinned, so our reference is safe.
250 */
251 dl = alias->d_fsdata;
252 mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
253 (unsigned long long)parent_blkno,
254 (unsigned long long)OCFS2_I(inode)->ip_blkno);
255
256 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
257 " \"%pd\": old parent: %llu, new: %llu\n",
258 dentry,
259 (unsigned long long)parent_blkno,
260 (unsigned long long)dl->dl_parent_blkno);
261
262 trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name,
263 (unsigned long long)parent_blkno,
264 (unsigned long long)OCFS2_I(inode)->ip_blkno);
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 all attaches, in case
282 * the struct inode gets blown away by the downconvert thread?
283 */
284 dl->dl_inode = igrab(inode);
285 dl->dl_parent_blkno = parent_blkno;
286 ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
287
288out_attach:
289 spin_lock(&dentry_attach_lock);
290 if (unlikely(dentry->d_fsdata && !alias)) {
291 /* d_fsdata is set by a racing thread which is doing
292 * the same thing as this thread is doing. Leave the racing
293 * thread going ahead and we return here.
294 */
295 spin_unlock(&dentry_attach_lock);
296 iput(dl->dl_inode);
297 ocfs2_lock_res_free(&dl->dl_lockres);
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 level lock. From now on,
308 * we'll have a notification if one of these names is
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 allocation and do the iput().
319 * We need to do this because error here means no d_instantiate(),
320 * which means iput() will not be called during dput(dentry).
321 */
322 if (ret < 0 && !alias) {
323 ocfs2_lock_res_free(&dl->dl_lockres);
324 BUG_ON(dl->dl_count != 1);
325 spin_lock(&dentry_attach_lock);
326 dentry->d_fsdata = NULL;
327 spin_unlock(&dentry_attach_lock);
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 detached from the inodes
341 * alias list, so there's no way that the locking code can find it.
342 *
343 * The interesting stuff happens when we determine that our lock needs
344 * to go away because this is the last subdir alias in the
345 * system. This function needs to handle a couple things:
346 *
347 * 1) Synchronizing lock shutdown with the downconvert threads. This
348 * is already handled for us via the lockres release drop function
349 * called in ocfs2_release_dentry_lock()
350 *
351 * 2) A race may occur when we're doing our lock shutdown and
352 * another process wants to create a new dentry lock. Right now we
353 * let them race, which means that for a very short while, this
354 * node might have two locks on a lock resource. This should be a
355 * problem though because one of them is in the process of being
356 * thrown out.
357 */
358static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
359 struct ocfs2_dentry_lock *dl)
360{
361 iput(dl->dl_inode);
362 ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
363 ocfs2_lock_res_free(&dl->dl_lockres);
364 kfree(dl);
365}
366
367void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
368 struct ocfs2_dentry_lock *dl)
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
383static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
384{
385 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
386
387 if (!dl) {
388 /*
389 * No dentry lock is ok if we're disconnected or
390 * unhashed.
391 */
392 if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
393 !d_unhashed(dentry)) {
394 unsigned long long ino = 0ULL;
395 if (inode)
396 ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
397 mlog(ML_ERROR, "Dentry is missing cluster lock. "
398 "inode: %llu, d_flags: 0x%x, d_name: %pd\n",
399 ino, dentry->d_flags, dentry);
400 }
401
402 goto out;
403 }
404
405 mlog_bug_on_msg(dl->dl_count == 0, "dentry: %pd, count: %u\n",
406 dentry, dl->dl_count);
407
408 ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
409
410out:
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 parent dir and name of
418 * "target", which will be thrown away.
419 *
420 * We manually update the lock of "dentry" if need be.
421 *
422 * "target" doesn't have it's dentry lock touched - we allow the later
423 * dput() to handle this for us.
424 *
425 * This is called during ocfs2_rename(), while holding parent
426 * directory locks. The dentries have already been deleted on other
427 * nodes via ocfs2_remote_dentry_delete().
428 *
429 * Normally, the VFS handles the d_move() for the file system, after
430 * the ->rename() callback. OCFS2 wants to handle this internally, so
431 * the new lock can be created atomically with respect to the cluster.
432 */
433void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
434 struct inode *old_dir, struct inode *new_dir)
435{
436 int ret;
437 struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
438 struct inode *inode = d_inode(dentry);
439
440 /*
441 * Move within the same directory, so the actual lock info won't
442 * change.
443 *
444 * XXX: Is there any advantage to dropping the lock here?
445 */
446 if (old_dir == new_dir)
447 goto out_move;
448
449 ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
450
451 dentry->d_fsdata = NULL;
452 ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
453 if (ret)
454 mlog_errno(ret);
455
456out_move:
457 d_move(dentry, target);
458}
459
460const struct dentry_operations ocfs2_dentry_ops = {
461 .d_revalidate = ocfs2_dentry_revalidate,
462 .d_iput = ocfs2_dentry_iput,
463};
1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dcache.c
5 *
6 * dentry cache handling code
7 *
8 * Copyright (C) 2002, 2004 Oracle. All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/types.h>
28#include <linux/slab.h>
29#include <linux/namei.h>
30
31#include <cluster/masklog.h>
32
33#include "ocfs2.h"
34
35#include "alloc.h"
36#include "dcache.h"
37#include "dlmglue.h"
38#include "file.h"
39#include "inode.h"
40#include "super.h"
41#include "ocfs2_trace.h"
42
43void ocfs2_dentry_attach_gen(struct dentry *dentry)
44{
45 unsigned long gen =
46 OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen;
47 BUG_ON(dentry->d_inode);
48 dentry->d_fsdata = (void *)gen;
49}
50
51
52static int ocfs2_dentry_revalidate(struct dentry *dentry,
53 struct nameidata *nd)
54{
55 struct inode *inode;
56 int ret = 0; /* if all else fails, just return false */
57 struct ocfs2_super *osb;
58
59 if (nd && nd->flags & LOOKUP_RCU)
60 return -ECHILD;
61
62 inode = dentry->d_inode;
63 osb = OCFS2_SB(dentry->d_sb);
64
65 trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len,
66 dentry->d_name.name);
67
68 /* For a negative dentry -
69 * check the generation number of the parent and compare with the
70 * one stored in the inode.
71 */
72 if (inode == NULL) {
73 unsigned long gen = (unsigned long) dentry->d_fsdata;
74 unsigned long pgen =
75 OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen;
76
77 trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len,
78 dentry->d_name.name,
79 pgen, gen);
80 if (gen != pgen)
81 goto bail;
82 goto valid;
83 }
84
85 BUG_ON(!osb);
86
87 if (inode == osb->root_inode || is_bad_inode(inode))
88 goto bail;
89
90 spin_lock(&OCFS2_I(inode)->ip_lock);
91 /* did we or someone else delete this inode? */
92 if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
93 spin_unlock(&OCFS2_I(inode)->ip_lock);
94 trace_ocfs2_dentry_revalidate_delete(
95 (unsigned long long)OCFS2_I(inode)->ip_blkno);
96 goto bail;
97 }
98 spin_unlock(&OCFS2_I(inode)->ip_lock);
99
100 /*
101 * We don't need a cluster lock to test this because once an
102 * inode nlink hits zero, it never goes back.
103 */
104 if (inode->i_nlink == 0) {
105 trace_ocfs2_dentry_revalidate_orphaned(
106 (unsigned long long)OCFS2_I(inode)->ip_blkno,
107 S_ISDIR(inode->i_mode));
108 goto bail;
109 }
110
111 /*
112 * If the last lookup failed to create dentry lock, let us
113 * redo it.
114 */
115 if (!dentry->d_fsdata) {
116 trace_ocfs2_dentry_revalidate_nofsdata(
117 (unsigned long long)OCFS2_I(inode)->ip_blkno);
118 goto bail;
119 }
120
121valid:
122 ret = 1;
123
124bail:
125 trace_ocfs2_dentry_revalidate_ret(ret);
126 return ret;
127}
128
129static int ocfs2_match_dentry(struct dentry *dentry,
130 u64 parent_blkno,
131 int skip_unhashed)
132{
133 struct inode *parent;
134
135 /*
136 * ocfs2_lookup() does a d_splice_alias() _before_ attaching
137 * to the lock data, so we skip those here, otherwise
138 * ocfs2_dentry_attach_lock() will get its original dentry
139 * back.
140 */
141 if (!dentry->d_fsdata)
142 return 0;
143
144 if (!dentry->d_parent)
145 return 0;
146
147 if (skip_unhashed && d_unhashed(dentry))
148 return 0;
149
150 parent = dentry->d_parent->d_inode;
151 /* Negative parent dentry? */
152 if (!parent)
153 return 0;
154
155 /* Name is in a different directory. */
156 if (OCFS2_I(parent)->ip_blkno != parent_blkno)
157 return 0;
158
159 return 1;
160}
161
162/*
163 * Walk the inode alias list, and find a dentry which has a given
164 * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
165 * is looking for a dentry_lock reference. The downconvert thread is
166 * looking to unhash aliases, so we allow it to skip any that already
167 * have that property.
168 */
169struct dentry *ocfs2_find_local_alias(struct inode *inode,
170 u64 parent_blkno,
171 int skip_unhashed)
172{
173 struct list_head *p;
174 struct dentry *dentry = NULL;
175
176 spin_lock(&inode->i_lock);
177 list_for_each(p, &inode->i_dentry) {
178 dentry = list_entry(p, struct dentry, d_alias);
179
180 spin_lock(&dentry->d_lock);
181 if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
182 trace_ocfs2_find_local_alias(dentry->d_name.len,
183 dentry->d_name.name);
184
185 dget_dlock(dentry);
186 spin_unlock(&dentry->d_lock);
187 break;
188 }
189 spin_unlock(&dentry->d_lock);
190
191 dentry = NULL;
192 }
193
194 spin_unlock(&inode->i_lock);
195
196 return dentry;
197}
198
199DEFINE_SPINLOCK(dentry_attach_lock);
200
201/*
202 * Attach this dentry to a cluster lock.
203 *
204 * Dentry locks cover all links in a given directory to a particular
205 * inode. We do this so that ocfs2 can build a lock name which all
206 * nodes in the cluster can agree on at all times. Shoving full names
207 * in the cluster lock won't work due to size restrictions. Covering
208 * links inside of a directory is a good compromise because it still
209 * allows us to use the parent directory lock to synchronize
210 * operations.
211 *
212 * Call this function with the parent dir semaphore and the parent dir
213 * cluster lock held.
214 *
215 * The dir semaphore will protect us from having to worry about
216 * concurrent processes on our node trying to attach a lock at the
217 * same time.
218 *
219 * The dir cluster lock (held at either PR or EX mode) protects us
220 * from unlink and rename on other nodes.
221 *
222 * A dput() can happen asynchronously due to pruning, so we cover
223 * attaching and detaching the dentry lock with a
224 * dentry_attach_lock.
225 *
226 * A node which has done lookup on a name retains a protected read
227 * lock until final dput. If the user requests and unlink or rename,
228 * the protected read is upgraded to an exclusive lock. Other nodes
229 * who have seen the dentry will then be informed that they need to
230 * downgrade their lock, which will involve d_delete on the
231 * dentry. This happens in ocfs2_dentry_convert_worker().
232 */
233int ocfs2_dentry_attach_lock(struct dentry *dentry,
234 struct inode *inode,
235 u64 parent_blkno)
236{
237 int ret;
238 struct dentry *alias;
239 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
240
241 trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name,
242 (unsigned long long)parent_blkno, dl);
243
244 /*
245 * Negative dentry. We ignore these for now.
246 *
247 * XXX: Could we can improve ocfs2_dentry_revalidate() by
248 * tracking these?
249 */
250 if (!inode)
251 return 0;
252
253 if (!dentry->d_inode && dentry->d_fsdata) {
254 /* Converting a negative dentry to positive
255 Clear dentry->d_fsdata */
256 dentry->d_fsdata = dl = NULL;
257 }
258
259 if (dl) {
260 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
261 " \"%.*s\": old parent: %llu, new: %llu\n",
262 dentry->d_name.len, dentry->d_name.name,
263 (unsigned long long)parent_blkno,
264 (unsigned long long)dl->dl_parent_blkno);
265 return 0;
266 }
267
268 alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
269 if (alias) {
270 /*
271 * Great, an alias exists, which means we must have a
272 * dentry lock already. We can just grab the lock off
273 * the alias and add it to the list.
274 *
275 * We're depending here on the fact that this dentry
276 * was found and exists in the dcache and so must have
277 * a reference to the dentry_lock because we can't
278 * race creates. Final dput() cannot happen on it
279 * since we have it pinned, so our reference is safe.
280 */
281 dl = alias->d_fsdata;
282 mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
283 (unsigned long long)parent_blkno,
284 (unsigned long long)OCFS2_I(inode)->ip_blkno);
285
286 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
287 " \"%.*s\": old parent: %llu, new: %llu\n",
288 dentry->d_name.len, dentry->d_name.name,
289 (unsigned long long)parent_blkno,
290 (unsigned long long)dl->dl_parent_blkno);
291
292 trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name,
293 (unsigned long long)parent_blkno,
294 (unsigned long long)OCFS2_I(inode)->ip_blkno);
295
296 goto out_attach;
297 }
298
299 /*
300 * There are no other aliases
301 */
302 dl = kmalloc(sizeof(*dl), GFP_NOFS);
303 if (!dl) {
304 ret = -ENOMEM;
305 mlog_errno(ret);
306 return ret;
307 }
308
309 dl->dl_count = 0;
310 /*
311 * Does this have to happen below, for all attaches, in case
312 * the struct inode gets blown away by the downconvert thread?
313 */
314 dl->dl_inode = igrab(inode);
315 dl->dl_parent_blkno = parent_blkno;
316 ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
317
318out_attach:
319 spin_lock(&dentry_attach_lock);
320 dentry->d_fsdata = dl;
321 dl->dl_count++;
322 spin_unlock(&dentry_attach_lock);
323
324 /*
325 * This actually gets us our PRMODE level lock. From now on,
326 * we'll have a notification if one of these names is
327 * destroyed on another node.
328 */
329 ret = ocfs2_dentry_lock(dentry, 0);
330 if (!ret)
331 ocfs2_dentry_unlock(dentry, 0);
332 else
333 mlog_errno(ret);
334
335 /*
336 * In case of error, manually free the allocation and do the iput().
337 * We need to do this because error here means no d_instantiate(),
338 * which means iput() will not be called during dput(dentry).
339 */
340 if (ret < 0 && !alias) {
341 ocfs2_lock_res_free(&dl->dl_lockres);
342 BUG_ON(dl->dl_count != 1);
343 spin_lock(&dentry_attach_lock);
344 dentry->d_fsdata = NULL;
345 spin_unlock(&dentry_attach_lock);
346 kfree(dl);
347 iput(inode);
348 }
349
350 dput(alias);
351
352 return ret;
353}
354
355DEFINE_SPINLOCK(dentry_list_lock);
356
357/* We limit the number of dentry locks to drop in one go. We have
358 * this limit so that we don't starve other users of ocfs2_wq. */
359#define DL_INODE_DROP_COUNT 64
360
361/* Drop inode references from dentry locks */
362static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count)
363{
364 struct ocfs2_dentry_lock *dl;
365
366 spin_lock(&dentry_list_lock);
367 while (osb->dentry_lock_list && (drop_count < 0 || drop_count--)) {
368 dl = osb->dentry_lock_list;
369 osb->dentry_lock_list = dl->dl_next;
370 spin_unlock(&dentry_list_lock);
371 iput(dl->dl_inode);
372 kfree(dl);
373 spin_lock(&dentry_list_lock);
374 }
375 spin_unlock(&dentry_list_lock);
376}
377
378void ocfs2_drop_dl_inodes(struct work_struct *work)
379{
380 struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
381 dentry_lock_work);
382
383 __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT);
384 /*
385 * Don't queue dropping if umount is in progress. We flush the
386 * list in ocfs2_dismount_volume
387 */
388 spin_lock(&dentry_list_lock);
389 if (osb->dentry_lock_list &&
390 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
391 queue_work(ocfs2_wq, &osb->dentry_lock_work);
392 spin_unlock(&dentry_list_lock);
393}
394
395/* Flush the whole work queue */
396void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
397{
398 __ocfs2_drop_dl_inodes(osb, -1);
399}
400
401/*
402 * ocfs2_dentry_iput() and friends.
403 *
404 * At this point, our particular dentry is detached from the inodes
405 * alias list, so there's no way that the locking code can find it.
406 *
407 * The interesting stuff happens when we determine that our lock needs
408 * to go away because this is the last subdir alias in the
409 * system. This function needs to handle a couple things:
410 *
411 * 1) Synchronizing lock shutdown with the downconvert threads. This
412 * is already handled for us via the lockres release drop function
413 * called in ocfs2_release_dentry_lock()
414 *
415 * 2) A race may occur when we're doing our lock shutdown and
416 * another process wants to create a new dentry lock. Right now we
417 * let them race, which means that for a very short while, this
418 * node might have two locks on a lock resource. This should be a
419 * problem though because one of them is in the process of being
420 * thrown out.
421 */
422static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
423 struct ocfs2_dentry_lock *dl)
424{
425 ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
426 ocfs2_lock_res_free(&dl->dl_lockres);
427
428 /* We leave dropping of inode reference to ocfs2_wq as that can
429 * possibly lead to inode deletion which gets tricky */
430 spin_lock(&dentry_list_lock);
431 if (!osb->dentry_lock_list &&
432 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
433 queue_work(ocfs2_wq, &osb->dentry_lock_work);
434 dl->dl_next = osb->dentry_lock_list;
435 osb->dentry_lock_list = dl;
436 spin_unlock(&dentry_list_lock);
437}
438
439void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
440 struct ocfs2_dentry_lock *dl)
441{
442 int unlock;
443
444 BUG_ON(dl->dl_count == 0);
445
446 spin_lock(&dentry_attach_lock);
447 dl->dl_count--;
448 unlock = !dl->dl_count;
449 spin_unlock(&dentry_attach_lock);
450
451 if (unlock)
452 ocfs2_drop_dentry_lock(osb, dl);
453}
454
455static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
456{
457 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
458
459 if (!dl) {
460 /*
461 * No dentry lock is ok if we're disconnected or
462 * unhashed.
463 */
464 if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
465 !d_unhashed(dentry)) {
466 unsigned long long ino = 0ULL;
467 if (inode)
468 ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
469 mlog(ML_ERROR, "Dentry is missing cluster lock. "
470 "inode: %llu, d_flags: 0x%x, d_name: %.*s\n",
471 ino, dentry->d_flags, dentry->d_name.len,
472 dentry->d_name.name);
473 }
474
475 goto out;
476 }
477
478 mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n",
479 dentry->d_name.len, dentry->d_name.name,
480 dl->dl_count);
481
482 ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
483
484out:
485 iput(inode);
486}
487
488/*
489 * d_move(), but keep the locks in sync.
490 *
491 * When we are done, "dentry" will have the parent dir and name of
492 * "target", which will be thrown away.
493 *
494 * We manually update the lock of "dentry" if need be.
495 *
496 * "target" doesn't have it's dentry lock touched - we allow the later
497 * dput() to handle this for us.
498 *
499 * This is called during ocfs2_rename(), while holding parent
500 * directory locks. The dentries have already been deleted on other
501 * nodes via ocfs2_remote_dentry_delete().
502 *
503 * Normally, the VFS handles the d_move() for the file system, after
504 * the ->rename() callback. OCFS2 wants to handle this internally, so
505 * the new lock can be created atomically with respect to the cluster.
506 */
507void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
508 struct inode *old_dir, struct inode *new_dir)
509{
510 int ret;
511 struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
512 struct inode *inode = dentry->d_inode;
513
514 /*
515 * Move within the same directory, so the actual lock info won't
516 * change.
517 *
518 * XXX: Is there any advantage to dropping the lock here?
519 */
520 if (old_dir == new_dir)
521 goto out_move;
522
523 ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
524
525 dentry->d_fsdata = NULL;
526 ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
527 if (ret)
528 mlog_errno(ret);
529
530out_move:
531 d_move(dentry, target);
532}
533
534const struct dentry_operations ocfs2_dentry_ops = {
535 .d_revalidate = ocfs2_dentry_revalidate,
536 .d_iput = ocfs2_dentry_iput,
537};