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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 "ocfs2_trace.h"
41
42void ocfs2_dentry_attach_gen(struct dentry *dentry)
43{
44 unsigned long gen =
45 OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
46 BUG_ON(d_inode(dentry));
47 dentry->d_fsdata = (void *)gen;
48}
49
50
51static int ocfs2_dentry_revalidate(struct dentry *dentry, unsigned int flags)
52{
53 struct inode *inode;
54 int ret = 0; /* if all else fails, just return false */
55 struct ocfs2_super *osb;
56
57 if (flags & LOOKUP_RCU)
58 return -ECHILD;
59
60 inode = d_inode(dentry);
61 osb = OCFS2_SB(dentry->d_sb);
62
63 trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len,
64 dentry->d_name.name);
65
66 /* For a negative dentry -
67 * check the generation number of the parent and compare with the
68 * one stored in the inode.
69 */
70 if (inode == NULL) {
71 unsigned long gen = (unsigned long) dentry->d_fsdata;
72 unsigned long pgen;
73 spin_lock(&dentry->d_lock);
74 pgen = OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
75 spin_unlock(&dentry->d_lock);
76 trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len,
77 dentry->d_name.name,
78 pgen, gen);
79 if (gen != pgen)
80 goto bail;
81 goto valid;
82 }
83
84 BUG_ON(!osb);
85
86 if (inode == osb->root_inode || is_bad_inode(inode))
87 goto bail;
88
89 spin_lock(&OCFS2_I(inode)->ip_lock);
90 /* did we or someone else delete this inode? */
91 if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
92 spin_unlock(&OCFS2_I(inode)->ip_lock);
93 trace_ocfs2_dentry_revalidate_delete(
94 (unsigned long long)OCFS2_I(inode)->ip_blkno);
95 goto bail;
96 }
97 spin_unlock(&OCFS2_I(inode)->ip_lock);
98
99 /*
100 * We don't need a cluster lock to test this because once an
101 * inode nlink hits zero, it never goes back.
102 */
103 if (inode->i_nlink == 0) {
104 trace_ocfs2_dentry_revalidate_orphaned(
105 (unsigned long long)OCFS2_I(inode)->ip_blkno,
106 S_ISDIR(inode->i_mode));
107 goto bail;
108 }
109
110 /*
111 * If the last lookup failed to create dentry lock, let us
112 * redo it.
113 */
114 if (!dentry->d_fsdata) {
115 trace_ocfs2_dentry_revalidate_nofsdata(
116 (unsigned long long)OCFS2_I(inode)->ip_blkno);
117 goto bail;
118 }
119
120valid:
121 ret = 1;
122
123bail:
124 trace_ocfs2_dentry_revalidate_ret(ret);
125 return ret;
126}
127
128static int ocfs2_match_dentry(struct dentry *dentry,
129 u64 parent_blkno,
130 int skip_unhashed)
131{
132 struct inode *parent;
133
134 /*
135 * ocfs2_lookup() does a d_splice_alias() _before_ attaching
136 * to the lock data, so we skip those here, otherwise
137 * ocfs2_dentry_attach_lock() will get its original dentry
138 * back.
139 */
140 if (!dentry->d_fsdata)
141 return 0;
142
143 if (!dentry->d_parent)
144 return 0;
145
146 if (skip_unhashed && d_unhashed(dentry))
147 return 0;
148
149 parent = d_inode(dentry->d_parent);
150 /* Negative parent dentry? */
151 if (!parent)
152 return 0;
153
154 /* Name is in a different directory. */
155 if (OCFS2_I(parent)->ip_blkno != parent_blkno)
156 return 0;
157
158 return 1;
159}
160
161/*
162 * Walk the inode alias list, and find a dentry which has a given
163 * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
164 * is looking for a dentry_lock reference. The downconvert thread is
165 * looking to unhash aliases, so we allow it to skip any that already
166 * have that property.
167 */
168struct dentry *ocfs2_find_local_alias(struct inode *inode,
169 u64 parent_blkno,
170 int skip_unhashed)
171{
172 struct dentry *dentry;
173
174 spin_lock(&inode->i_lock);
175 hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
176 spin_lock(&dentry->d_lock);
177 if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
178 trace_ocfs2_find_local_alias(dentry->d_name.len,
179 dentry->d_name.name);
180
181 dget_dlock(dentry);
182 spin_unlock(&dentry->d_lock);
183 spin_unlock(&inode->i_lock);
184 return dentry;
185 }
186 spin_unlock(&dentry->d_lock);
187 }
188 spin_unlock(&inode->i_lock);
189 return NULL;
190}
191
192DEFINE_SPINLOCK(dentry_attach_lock);
193
194/*
195 * Attach this dentry to a cluster lock.
196 *
197 * Dentry locks cover all links in a given directory to a particular
198 * inode. We do this so that ocfs2 can build a lock name which all
199 * nodes in the cluster can agree on at all times. Shoving full names
200 * in the cluster lock won't work due to size restrictions. Covering
201 * links inside of a directory is a good compromise because it still
202 * allows us to use the parent directory lock to synchronize
203 * operations.
204 *
205 * Call this function with the parent dir semaphore and the parent dir
206 * cluster lock held.
207 *
208 * The dir semaphore will protect us from having to worry about
209 * concurrent processes on our node trying to attach a lock at the
210 * same time.
211 *
212 * The dir cluster lock (held at either PR or EX mode) protects us
213 * from unlink and rename on other nodes.
214 *
215 * A dput() can happen asynchronously due to pruning, so we cover
216 * attaching and detaching the dentry lock with a
217 * dentry_attach_lock.
218 *
219 * A node which has done lookup on a name retains a protected read
220 * lock until final dput. If the user requests and unlink or rename,
221 * the protected read is upgraded to an exclusive lock. Other nodes
222 * who have seen the dentry will then be informed that they need to
223 * downgrade their lock, which will involve d_delete on the
224 * dentry. This happens in ocfs2_dentry_convert_worker().
225 */
226int ocfs2_dentry_attach_lock(struct dentry *dentry,
227 struct inode *inode,
228 u64 parent_blkno)
229{
230 int ret;
231 struct dentry *alias;
232 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
233
234 trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name,
235 (unsigned long long)parent_blkno, dl);
236
237 /*
238 * Negative dentry. We ignore these for now.
239 *
240 * XXX: Could we can improve ocfs2_dentry_revalidate() by
241 * tracking these?
242 */
243 if (!inode)
244 return 0;
245
246 if (d_really_is_negative(dentry) && dentry->d_fsdata) {
247 /* Converting a negative dentry to positive
248 Clear dentry->d_fsdata */
249 dentry->d_fsdata = dl = NULL;
250 }
251
252 if (dl) {
253 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
254 " \"%pd\": old parent: %llu, new: %llu\n",
255 dentry,
256 (unsigned long long)parent_blkno,
257 (unsigned long long)dl->dl_parent_blkno);
258 return 0;
259 }
260
261 alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
262 if (alias) {
263 /*
264 * Great, an alias exists, which means we must have a
265 * dentry lock already. We can just grab the lock off
266 * the alias and add it to the list.
267 *
268 * We're depending here on the fact that this dentry
269 * was found and exists in the dcache and so must have
270 * a reference to the dentry_lock because we can't
271 * race creates. Final dput() cannot happen on it
272 * since we have it pinned, so our reference is safe.
273 */
274 dl = alias->d_fsdata;
275 mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
276 (unsigned long long)parent_blkno,
277 (unsigned long long)OCFS2_I(inode)->ip_blkno);
278
279 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
280 " \"%pd\": old parent: %llu, new: %llu\n",
281 dentry,
282 (unsigned long long)parent_blkno,
283 (unsigned long long)dl->dl_parent_blkno);
284
285 trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name,
286 (unsigned long long)parent_blkno,
287 (unsigned long long)OCFS2_I(inode)->ip_blkno);
288
289 goto out_attach;
290 }
291
292 /*
293 * There are no other aliases
294 */
295 dl = kmalloc(sizeof(*dl), GFP_NOFS);
296 if (!dl) {
297 ret = -ENOMEM;
298 mlog_errno(ret);
299 return ret;
300 }
301
302 dl->dl_count = 0;
303 /*
304 * Does this have to happen below, for all attaches, in case
305 * the struct inode gets blown away by the downconvert thread?
306 */
307 dl->dl_inode = igrab(inode);
308 dl->dl_parent_blkno = parent_blkno;
309 ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
310
311out_attach:
312 spin_lock(&dentry_attach_lock);
313 dentry->d_fsdata = dl;
314 dl->dl_count++;
315 spin_unlock(&dentry_attach_lock);
316
317 /*
318 * This actually gets us our PRMODE level lock. From now on,
319 * we'll have a notification if one of these names is
320 * destroyed on another node.
321 */
322 ret = ocfs2_dentry_lock(dentry, 0);
323 if (!ret)
324 ocfs2_dentry_unlock(dentry, 0);
325 else
326 mlog_errno(ret);
327
328 /*
329 * In case of error, manually free the allocation and do the iput().
330 * We need to do this because error here means no d_instantiate(),
331 * which means iput() will not be called during dput(dentry).
332 */
333 if (ret < 0 && !alias) {
334 ocfs2_lock_res_free(&dl->dl_lockres);
335 BUG_ON(dl->dl_count != 1);
336 spin_lock(&dentry_attach_lock);
337 dentry->d_fsdata = NULL;
338 spin_unlock(&dentry_attach_lock);
339 kfree(dl);
340 iput(inode);
341 }
342
343 dput(alias);
344
345 return ret;
346}
347
348/*
349 * ocfs2_dentry_iput() and friends.
350 *
351 * At this point, our particular dentry is detached from the inodes
352 * alias list, so there's no way that the locking code can find it.
353 *
354 * The interesting stuff happens when we determine that our lock needs
355 * to go away because this is the last subdir alias in the
356 * system. This function needs to handle a couple things:
357 *
358 * 1) Synchronizing lock shutdown with the downconvert threads. This
359 * is already handled for us via the lockres release drop function
360 * called in ocfs2_release_dentry_lock()
361 *
362 * 2) A race may occur when we're doing our lock shutdown and
363 * another process wants to create a new dentry lock. Right now we
364 * let them race, which means that for a very short while, this
365 * node might have two locks on a lock resource. This should be a
366 * problem though because one of them is in the process of being
367 * thrown out.
368 */
369static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
370 struct ocfs2_dentry_lock *dl)
371{
372 iput(dl->dl_inode);
373 ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
374 ocfs2_lock_res_free(&dl->dl_lockres);
375 kfree(dl);
376}
377
378void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
379 struct ocfs2_dentry_lock *dl)
380{
381 int unlock = 0;
382
383 BUG_ON(dl->dl_count == 0);
384
385 spin_lock(&dentry_attach_lock);
386 dl->dl_count--;
387 unlock = !dl->dl_count;
388 spin_unlock(&dentry_attach_lock);
389
390 if (unlock)
391 ocfs2_drop_dentry_lock(osb, dl);
392}
393
394static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
395{
396 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
397
398 if (!dl) {
399 /*
400 * No dentry lock is ok if we're disconnected or
401 * unhashed.
402 */
403 if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
404 !d_unhashed(dentry)) {
405 unsigned long long ino = 0ULL;
406 if (inode)
407 ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
408 mlog(ML_ERROR, "Dentry is missing cluster lock. "
409 "inode: %llu, d_flags: 0x%x, d_name: %pd\n",
410 ino, dentry->d_flags, dentry);
411 }
412
413 goto out;
414 }
415
416 mlog_bug_on_msg(dl->dl_count == 0, "dentry: %pd, count: %u\n",
417 dentry, dl->dl_count);
418
419 ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
420
421out:
422 iput(inode);
423}
424
425/*
426 * d_move(), but keep the locks in sync.
427 *
428 * When we are done, "dentry" will have the parent dir and name of
429 * "target", which will be thrown away.
430 *
431 * We manually update the lock of "dentry" if need be.
432 *
433 * "target" doesn't have it's dentry lock touched - we allow the later
434 * dput() to handle this for us.
435 *
436 * This is called during ocfs2_rename(), while holding parent
437 * directory locks. The dentries have already been deleted on other
438 * nodes via ocfs2_remote_dentry_delete().
439 *
440 * Normally, the VFS handles the d_move() for the file system, after
441 * the ->rename() callback. OCFS2 wants to handle this internally, so
442 * the new lock can be created atomically with respect to the cluster.
443 */
444void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
445 struct inode *old_dir, struct inode *new_dir)
446{
447 int ret;
448 struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
449 struct inode *inode = d_inode(dentry);
450
451 /*
452 * Move within the same directory, so the actual lock info won't
453 * change.
454 *
455 * XXX: Is there any advantage to dropping the lock here?
456 */
457 if (old_dir == new_dir)
458 goto out_move;
459
460 ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
461
462 dentry->d_fsdata = NULL;
463 ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
464 if (ret)
465 mlog_errno(ret);
466
467out_move:
468 d_move(dentry, target);
469}
470
471const struct dentry_operations ocfs2_dentry_ops = {
472 .d_revalidate = ocfs2_dentry_revalidate,
473 .d_iput = ocfs2_dentry_iput,
474};
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};