blob: edaded48e7e9f083ac7c67e72a9f031123f7844a [file] [log] [blame]
Mark Fashehccd979b2005-12-15 14:31:24 -08001/* -*- 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#define MLOG_MASK_PREFIX ML_DCACHE
32#include <cluster/masklog.h>
33
34#include "ocfs2.h"
35
36#include "alloc.h"
37#include "dcache.h"
Mark Fasheh80c05842006-09-08 14:43:18 -070038#include "dlmglue.h"
Mark Fashehccd979b2005-12-15 14:31:24 -080039#include "file.h"
40#include "inode.h"
Jan Karaea455f82009-01-12 23:20:31 +010041#include "super.h"
Mark Fashehccd979b2005-12-15 14:31:24 -080042
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -050043void 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
Mark Fasheh80c05842006-09-08 14:43:18 -070051
Mark Fashehccd979b2005-12-15 14:31:24 -080052static int ocfs2_dentry_revalidate(struct dentry *dentry,
53 struct nameidata *nd)
54{
55 struct inode *inode = dentry->d_inode;
56 int ret = 0; /* if all else fails, just return false */
Mark Fasheh80c05842006-09-08 14:43:18 -070057 struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
Mark Fashehccd979b2005-12-15 14:31:24 -080058
59 mlog_entry("(0x%p, '%.*s')\n", dentry,
60 dentry->d_name.len, dentry->d_name.name);
61
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -050062 /* For a negative dentry -
63 * check the generation number of the parent and compare with the
64 * one stored in the inode.
65 */
Mark Fashehccd979b2005-12-15 14:31:24 -080066 if (inode == NULL) {
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -050067 unsigned long gen = (unsigned long) dentry->d_fsdata;
68 unsigned long pgen =
69 OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen;
70 mlog(0, "negative dentry: %.*s parent gen: %lu "
71 "dentry gen: %lu\n",
72 dentry->d_name.len, dentry->d_name.name, pgen, gen);
73 if (gen != pgen)
74 goto bail;
75 goto valid;
Mark Fashehccd979b2005-12-15 14:31:24 -080076 }
77
Mark Fashehccd979b2005-12-15 14:31:24 -080078 BUG_ON(!osb);
79
Mark Fasheh80c05842006-09-08 14:43:18 -070080 if (inode == osb->root_inode || is_bad_inode(inode))
81 goto bail;
Mark Fashehccd979b2005-12-15 14:31:24 -080082
Mark Fasheh80c05842006-09-08 14:43:18 -070083 spin_lock(&OCFS2_I(inode)->ip_lock);
84 /* did we or someone else delete this inode? */
85 if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
86 spin_unlock(&OCFS2_I(inode)->ip_lock);
87 mlog(0, "inode (%llu) deleted, returning false\n",
88 (unsigned long long)OCFS2_I(inode)->ip_blkno);
89 goto bail;
90 }
91 spin_unlock(&OCFS2_I(inode)->ip_lock);
92
93 /*
94 * We don't need a cluster lock to test this because once an
95 * inode nlink hits zero, it never goes back.
96 */
97 if (inode->i_nlink == 0) {
98 mlog(0, "Inode %llu orphaned, returning false "
99 "dir = %d\n",
100 (unsigned long long)OCFS2_I(inode)->ip_blkno,
101 S_ISDIR(inode->i_mode));
102 goto bail;
Mark Fashehccd979b2005-12-15 14:31:24 -0800103 }
104
Tao Maa1b08e72009-08-27 14:46:56 +0800105 /*
106 * If the last lookup failed to create dentry lock, let us
107 * redo it.
108 */
109 if (!dentry->d_fsdata) {
110 mlog(0, "Inode %llu doesn't have dentry lock, "
111 "returning false\n",
112 (unsigned long long)OCFS2_I(inode)->ip_blkno);
113 goto bail;
114 }
115
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -0500116valid:
Mark Fashehccd979b2005-12-15 14:31:24 -0800117 ret = 1;
118
119bail:
120 mlog_exit(ret);
121
122 return ret;
123}
124
Mark Fasheh80c05842006-09-08 14:43:18 -0700125static int ocfs2_match_dentry(struct dentry *dentry,
126 u64 parent_blkno,
127 int skip_unhashed)
128{
129 struct inode *parent;
130
131 /*
132 * ocfs2_lookup() does a d_splice_alias() _before_ attaching
133 * to the lock data, so we skip those here, otherwise
134 * ocfs2_dentry_attach_lock() will get its original dentry
135 * back.
136 */
137 if (!dentry->d_fsdata)
138 return 0;
139
140 if (!dentry->d_parent)
141 return 0;
142
143 if (skip_unhashed && d_unhashed(dentry))
144 return 0;
145
146 parent = dentry->d_parent->d_inode;
147 /* Negative parent dentry? */
148 if (!parent)
149 return 0;
150
151 /* Name is in a different directory. */
152 if (OCFS2_I(parent)->ip_blkno != parent_blkno)
153 return 0;
154
155 return 1;
156}
157
158/*
159 * Walk the inode alias list, and find a dentry which has a given
160 * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
Mark Fasheh34d024f2007-09-24 15:56:19 -0700161 * is looking for a dentry_lock reference. The downconvert thread is
162 * looking to unhash aliases, so we allow it to skip any that already
163 * have that property.
Mark Fasheh80c05842006-09-08 14:43:18 -0700164 */
165struct dentry *ocfs2_find_local_alias(struct inode *inode,
166 u64 parent_blkno,
167 int skip_unhashed)
168{
169 struct list_head *p;
170 struct dentry *dentry = NULL;
171
172 spin_lock(&dcache_lock);
173
174 list_for_each(p, &inode->i_dentry) {
175 dentry = list_entry(p, struct dentry, d_alias);
176
177 if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
178 mlog(0, "dentry found: %.*s\n",
179 dentry->d_name.len, dentry->d_name.name);
180
181 dget_locked(dentry);
182 break;
183 }
184
185 dentry = NULL;
186 }
187
188 spin_unlock(&dcache_lock);
189
190 return dentry;
191}
192
Mark Fashehd680efe2006-09-08 14:14:34 -0700193DEFINE_SPINLOCK(dentry_attach_lock);
194
Mark Fasheh80c05842006-09-08 14:43:18 -0700195/*
196 * Attach this dentry to a cluster lock.
197 *
198 * Dentry locks cover all links in a given directory to a particular
199 * inode. We do this so that ocfs2 can build a lock name which all
200 * nodes in the cluster can agree on at all times. Shoving full names
201 * in the cluster lock won't work due to size restrictions. Covering
202 * links inside of a directory is a good compromise because it still
203 * allows us to use the parent directory lock to synchronize
204 * operations.
205 *
206 * Call this function with the parent dir semaphore and the parent dir
207 * cluster lock held.
208 *
209 * The dir semaphore will protect us from having to worry about
210 * concurrent processes on our node trying to attach a lock at the
211 * same time.
212 *
213 * The dir cluster lock (held at either PR or EX mode) protects us
214 * from unlink and rename on other nodes.
215 *
Mark Fasheh80c05842006-09-08 14:43:18 -0700216 * A dput() can happen asynchronously due to pruning, so we cover
217 * attaching and detaching the dentry lock with a
218 * dentry_attach_lock.
219 *
220 * A node which has done lookup on a name retains a protected read
221 * lock until final dput. If the user requests and unlink or rename,
222 * the protected read is upgraded to an exclusive lock. Other nodes
223 * who have seen the dentry will then be informed that they need to
224 * downgrade their lock, which will involve d_delete on the
225 * dentry. This happens in ocfs2_dentry_convert_worker().
226 */
227int ocfs2_dentry_attach_lock(struct dentry *dentry,
228 struct inode *inode,
Mark Fasheh0027dd52006-09-21 16:51:28 -0700229 u64 parent_blkno)
Mark Fasheh80c05842006-09-08 14:43:18 -0700230{
231 int ret;
232 struct dentry *alias;
233 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
234
Mark Fasheh0027dd52006-09-21 16:51:28 -0700235 mlog(0, "Attach \"%.*s\", parent %llu, fsdata: %p\n",
Mark Fasheh80c05842006-09-08 14:43:18 -0700236 dentry->d_name.len, dentry->d_name.name,
Mark Fasheh0027dd52006-09-21 16:51:28 -0700237 (unsigned long long)parent_blkno, dl);
Mark Fasheh80c05842006-09-08 14:43:18 -0700238
239 /*
240 * Negative dentry. We ignore these for now.
241 *
242 * XXX: Could we can improve ocfs2_dentry_revalidate() by
243 * tracking these?
244 */
245 if (!inode)
246 return 0;
247
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -0500248 if (!dentry->d_inode && dentry->d_fsdata) {
249 /* Converting a negative dentry to positive
250 Clear dentry->d_fsdata */
251 dentry->d_fsdata = dl = NULL;
252 }
253
Mark Fasheh80c05842006-09-08 14:43:18 -0700254 if (dl) {
255 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
256 " \"%.*s\": old parent: %llu, new: %llu\n",
257 dentry->d_name.len, dentry->d_name.name,
258 (unsigned long long)parent_blkno,
259 (unsigned long long)dl->dl_parent_blkno);
260 return 0;
261 }
262
263 alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
264 if (alias) {
265 /*
266 * Great, an alias exists, which means we must have a
267 * dentry lock already. We can just grab the lock off
268 * the alias and add it to the list.
269 *
270 * We're depending here on the fact that this dentry
271 * was found and exists in the dcache and so must have
272 * a reference to the dentry_lock because we can't
273 * race creates. Final dput() cannot happen on it
274 * since we have it pinned, so our reference is safe.
275 */
276 dl = alias->d_fsdata;
Mark Fasheh0027dd52006-09-21 16:51:28 -0700277 mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
Mark Fasheh80c05842006-09-08 14:43:18 -0700278 (unsigned long long)parent_blkno,
Mark Fasheh0027dd52006-09-21 16:51:28 -0700279 (unsigned long long)OCFS2_I(inode)->ip_blkno);
Mark Fasheh80c05842006-09-08 14:43:18 -0700280
281 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
282 " \"%.*s\": old parent: %llu, new: %llu\n",
283 dentry->d_name.len, dentry->d_name.name,
284 (unsigned long long)parent_blkno,
285 (unsigned long long)dl->dl_parent_blkno);
286
287 mlog(0, "Found: %s\n", dl->dl_lockres.l_name);
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
Mark Fasheh34d024f2007-09-24 15:56:19 -0700305 * the struct inode gets blown away by the downconvert thread?
Mark Fasheh80c05842006-09-08 14:43:18 -0700306 */
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 /*
Mark Fasheh80c05842006-09-08 14:43:18 -0700318 * 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);
Mark Fasheh0027dd52006-09-21 16:51:28 -0700323 if (!ret)
324 ocfs2_dentry_unlock(dentry, 0);
325 else
Mark Fasheh80c05842006-09-08 14:43:18 -0700326 mlog_errno(ret);
Mark Fasheh80c05842006-09-08 14:43:18 -0700327
Sunil Mushrana5a0a632009-04-20 21:34:18 -0700328 /*
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
Mark Fasheh80c05842006-09-08 14:43:18 -0700343 dput(alias);
344
345 return ret;
346}
347
Jan Karaf7b1aa62009-07-20 12:12:36 +0200348DEFINE_SPINLOCK(dentry_list_lock);
Jan Karaea455f82009-01-12 23:20:31 +0100349
350/* We limit the number of dentry locks to drop in one go. We have
351 * this limit so that we don't starve other users of ocfs2_wq. */
352#define DL_INODE_DROP_COUNT 64
353
354/* Drop inode references from dentry locks */
Jan Karaf7b1aa62009-07-20 12:12:36 +0200355static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count)
Jan Karaea455f82009-01-12 23:20:31 +0100356{
Jan Karaea455f82009-01-12 23:20:31 +0100357 struct ocfs2_dentry_lock *dl;
Jan Karaea455f82009-01-12 23:20:31 +0100358
359 spin_lock(&dentry_list_lock);
Jan Karaf7b1aa62009-07-20 12:12:36 +0200360 while (osb->dentry_lock_list && (drop_count < 0 || drop_count--)) {
Jan Karaea455f82009-01-12 23:20:31 +0100361 dl = osb->dentry_lock_list;
362 osb->dentry_lock_list = dl->dl_next;
363 spin_unlock(&dentry_list_lock);
364 iput(dl->dl_inode);
365 kfree(dl);
366 spin_lock(&dentry_list_lock);
367 }
Jan Karaf7b1aa62009-07-20 12:12:36 +0200368 spin_unlock(&dentry_list_lock);
369}
370
371void ocfs2_drop_dl_inodes(struct work_struct *work)
372{
373 struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
374 dentry_lock_work);
375
376 __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT);
377 /*
378 * Don't queue dropping if umount is in progress. We flush the
379 * list in ocfs2_dismount_volume
380 */
381 spin_lock(&dentry_list_lock);
382 if (osb->dentry_lock_list &&
383 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
Jan Karaea455f82009-01-12 23:20:31 +0100384 queue_work(ocfs2_wq, &osb->dentry_lock_work);
385 spin_unlock(&dentry_list_lock);
386}
387
Jan Karaf7b1aa62009-07-20 12:12:36 +0200388/* Flush the whole work queue */
389void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
390{
391 __ocfs2_drop_dl_inodes(osb, -1);
392}
393
Mark Fasheh80c05842006-09-08 14:43:18 -0700394/*
395 * ocfs2_dentry_iput() and friends.
396 *
397 * At this point, our particular dentry is detached from the inodes
398 * alias list, so there's no way that the locking code can find it.
399 *
400 * The interesting stuff happens when we determine that our lock needs
401 * to go away because this is the last subdir alias in the
402 * system. This function needs to handle a couple things:
403 *
404 * 1) Synchronizing lock shutdown with the downconvert threads. This
405 * is already handled for us via the lockres release drop function
406 * called in ocfs2_release_dentry_lock()
407 *
408 * 2) A race may occur when we're doing our lock shutdown and
409 * another process wants to create a new dentry lock. Right now we
410 * let them race, which means that for a very short while, this
411 * node might have two locks on a lock resource. This should be a
412 * problem though because one of them is in the process of being
413 * thrown out.
414 */
415static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
416 struct ocfs2_dentry_lock *dl)
417{
418 ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
419 ocfs2_lock_res_free(&dl->dl_lockres);
Jan Karaea455f82009-01-12 23:20:31 +0100420
421 /* We leave dropping of inode reference to ocfs2_wq as that can
422 * possibly lead to inode deletion which gets tricky */
423 spin_lock(&dentry_list_lock);
Jan Karaf7b1aa62009-07-20 12:12:36 +0200424 if (!osb->dentry_lock_list &&
425 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
Jan Karaea455f82009-01-12 23:20:31 +0100426 queue_work(ocfs2_wq, &osb->dentry_lock_work);
427 dl->dl_next = osb->dentry_lock_list;
428 osb->dentry_lock_list = dl;
429 spin_unlock(&dentry_list_lock);
Mark Fasheh80c05842006-09-08 14:43:18 -0700430}
431
432void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
433 struct ocfs2_dentry_lock *dl)
434{
Jan Karaea455f82009-01-12 23:20:31 +0100435 int unlock;
Mark Fasheh80c05842006-09-08 14:43:18 -0700436
437 BUG_ON(dl->dl_count == 0);
438
439 spin_lock(&dentry_attach_lock);
440 dl->dl_count--;
441 unlock = !dl->dl_count;
442 spin_unlock(&dentry_attach_lock);
443
444 if (unlock)
445 ocfs2_drop_dentry_lock(osb, dl);
446}
447
448static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
449{
450 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
451
Mark Fashehbccb9da2007-11-07 16:35:14 -0800452 if (!dl) {
453 /*
454 * No dentry lock is ok if we're disconnected or
455 * unhashed.
456 */
457 if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
458 !d_unhashed(dentry)) {
459 unsigned long long ino = 0ULL;
460 if (inode)
461 ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
462 mlog(ML_ERROR, "Dentry is missing cluster lock. "
463 "inode: %llu, d_flags: 0x%x, d_name: %.*s\n",
464 ino, dentry->d_flags, dentry->d_name.len,
465 dentry->d_name.name);
466 }
Mark Fasheh80c05842006-09-08 14:43:18 -0700467
Mark Fasheh80c05842006-09-08 14:43:18 -0700468 goto out;
Mark Fashehbccb9da2007-11-07 16:35:14 -0800469 }
Mark Fasheh80c05842006-09-08 14:43:18 -0700470
471 mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n",
472 dentry->d_name.len, dentry->d_name.name,
473 dl->dl_count);
474
475 ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
476
477out:
478 iput(inode);
Goldwyn Rodrigues5e98d492010-06-28 10:04:32 -0500479 ocfs2_dentry_attach_gen(dentry);
Mark Fasheh80c05842006-09-08 14:43:18 -0700480}
481
482/*
483 * d_move(), but keep the locks in sync.
484 *
485 * When we are done, "dentry" will have the parent dir and name of
486 * "target", which will be thrown away.
487 *
488 * We manually update the lock of "dentry" if need be.
489 *
490 * "target" doesn't have it's dentry lock touched - we allow the later
491 * dput() to handle this for us.
492 *
493 * This is called during ocfs2_rename(), while holding parent
494 * directory locks. The dentries have already been deleted on other
495 * nodes via ocfs2_remote_dentry_delete().
496 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200497 * Normally, the VFS handles the d_move() for the file system, after
Mark Fasheh80c05842006-09-08 14:43:18 -0700498 * the ->rename() callback. OCFS2 wants to handle this internally, so
499 * the new lock can be created atomically with respect to the cluster.
500 */
501void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
502 struct inode *old_dir, struct inode *new_dir)
503{
504 int ret;
505 struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
506 struct inode *inode = dentry->d_inode;
507
508 /*
509 * Move within the same directory, so the actual lock info won't
510 * change.
511 *
512 * XXX: Is there any advantage to dropping the lock here?
513 */
514 if (old_dir == new_dir)
Mark Fasheh1ba9da22006-09-08 14:22:54 -0700515 goto out_move;
Mark Fasheh80c05842006-09-08 14:43:18 -0700516
517 ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
518
519 dentry->d_fsdata = NULL;
Mark Fasheh0027dd52006-09-21 16:51:28 -0700520 ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
Mark Fasheh80c05842006-09-08 14:43:18 -0700521 if (ret)
522 mlog_errno(ret);
Mark Fasheh1ba9da22006-09-08 14:22:54 -0700523
524out_move:
525 d_move(dentry, target);
Mark Fasheh80c05842006-09-08 14:43:18 -0700526}
527
Al Virod8fba0f2009-02-20 06:00:26 +0000528const struct dentry_operations ocfs2_dentry_ops = {
Mark Fashehccd979b2005-12-15 14:31:24 -0800529 .d_revalidate = ocfs2_dentry_revalidate,
Mark Fasheh80c05842006-09-08 14:43:18 -0700530 .d_iput = ocfs2_dentry_iput,
Mark Fashehccd979b2005-12-15 14:31:24 -0800531};