PM / yenta: Split resume into early and late parts (rev. 4)
[linux/fpc-iii.git] / fs / ocfs2 / dcache.c
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1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
4 * dcache.c
6 * dentry cache handling code
8 * Copyright (C) 2002, 2004 Oracle. All rights reserved.
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.
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.
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.
26 #include <linux/fs.h>
27 #include <linux/types.h>
28 #include <linux/slab.h>
29 #include <linux/namei.h>
31 #define MLOG_MASK_PREFIX ML_DCACHE
32 #include <cluster/masklog.h>
34 #include "ocfs2.h"
36 #include "alloc.h"
37 #include "dcache.h"
38 #include "dlmglue.h"
39 #include "file.h"
40 #include "inode.h"
41 #include "super.h"
44 static int ocfs2_dentry_revalidate(struct dentry *dentry,
45 struct nameidata *nd)
47 struct inode *inode = dentry->d_inode;
48 int ret = 0; /* if all else fails, just return false */
49 struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
51 mlog_entry("(0x%p, '%.*s')\n", dentry,
52 dentry->d_name.len, dentry->d_name.name);
54 /* Never trust a negative dentry - force a new lookup. */
55 if (inode == NULL) {
56 mlog(0, "negative dentry: %.*s\n", dentry->d_name.len,
57 dentry->d_name.name);
58 goto bail;
61 BUG_ON(!osb);
63 if (inode == osb->root_inode || is_bad_inode(inode))
64 goto bail;
66 spin_lock(&OCFS2_I(inode)->ip_lock);
67 /* did we or someone else delete this inode? */
68 if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
69 spin_unlock(&OCFS2_I(inode)->ip_lock);
70 mlog(0, "inode (%llu) deleted, returning false\n",
71 (unsigned long long)OCFS2_I(inode)->ip_blkno);
72 goto bail;
74 spin_unlock(&OCFS2_I(inode)->ip_lock);
77 * We don't need a cluster lock to test this because once an
78 * inode nlink hits zero, it never goes back.
80 if (inode->i_nlink == 0) {
81 mlog(0, "Inode %llu orphaned, returning false "
82 "dir = %d\n",
83 (unsigned long long)OCFS2_I(inode)->ip_blkno,
84 S_ISDIR(inode->i_mode));
85 goto bail;
89 * If the last lookup failed to create dentry lock, let us
90 * redo it.
92 if (!dentry->d_fsdata) {
93 mlog(0, "Inode %llu doesn't have dentry lock, "
94 "returning false\n",
95 (unsigned long long)OCFS2_I(inode)->ip_blkno);
96 goto bail;
99 ret = 1;
101 bail:
102 mlog_exit(ret);
104 return ret;
107 static int ocfs2_match_dentry(struct dentry *dentry,
108 u64 parent_blkno,
109 int skip_unhashed)
111 struct inode *parent;
114 * ocfs2_lookup() does a d_splice_alias() _before_ attaching
115 * to the lock data, so we skip those here, otherwise
116 * ocfs2_dentry_attach_lock() will get its original dentry
117 * back.
119 if (!dentry->d_fsdata)
120 return 0;
122 if (!dentry->d_parent)
123 return 0;
125 if (skip_unhashed && d_unhashed(dentry))
126 return 0;
128 parent = dentry->d_parent->d_inode;
129 /* Negative parent dentry? */
130 if (!parent)
131 return 0;
133 /* Name is in a different directory. */
134 if (OCFS2_I(parent)->ip_blkno != parent_blkno)
135 return 0;
137 return 1;
141 * Walk the inode alias list, and find a dentry which has a given
142 * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
143 * is looking for a dentry_lock reference. The downconvert thread is
144 * looking to unhash aliases, so we allow it to skip any that already
145 * have that property.
147 struct dentry *ocfs2_find_local_alias(struct inode *inode,
148 u64 parent_blkno,
149 int skip_unhashed)
151 struct list_head *p;
152 struct dentry *dentry = NULL;
154 spin_lock(&dcache_lock);
156 list_for_each(p, &inode->i_dentry) {
157 dentry = list_entry(p, struct dentry, d_alias);
159 if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
160 mlog(0, "dentry found: %.*s\n",
161 dentry->d_name.len, dentry->d_name.name);
163 dget_locked(dentry);
164 break;
167 dentry = NULL;
170 spin_unlock(&dcache_lock);
172 return dentry;
175 DEFINE_SPINLOCK(dentry_attach_lock);
178 * Attach this dentry to a cluster lock.
180 * Dentry locks cover all links in a given directory to a particular
181 * inode. We do this so that ocfs2 can build a lock name which all
182 * nodes in the cluster can agree on at all times. Shoving full names
183 * in the cluster lock won't work due to size restrictions. Covering
184 * links inside of a directory is a good compromise because it still
185 * allows us to use the parent directory lock to synchronize
186 * operations.
188 * Call this function with the parent dir semaphore and the parent dir
189 * cluster lock held.
191 * The dir semaphore will protect us from having to worry about
192 * concurrent processes on our node trying to attach a lock at the
193 * same time.
195 * The dir cluster lock (held at either PR or EX mode) protects us
196 * from unlink and rename on other nodes.
198 * A dput() can happen asynchronously due to pruning, so we cover
199 * attaching and detaching the dentry lock with a
200 * dentry_attach_lock.
202 * A node which has done lookup on a name retains a protected read
203 * lock until final dput. If the user requests and unlink or rename,
204 * the protected read is upgraded to an exclusive lock. Other nodes
205 * who have seen the dentry will then be informed that they need to
206 * downgrade their lock, which will involve d_delete on the
207 * dentry. This happens in ocfs2_dentry_convert_worker().
209 int ocfs2_dentry_attach_lock(struct dentry *dentry,
210 struct inode *inode,
211 u64 parent_blkno)
213 int ret;
214 struct dentry *alias;
215 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
217 mlog(0, "Attach \"%.*s\", parent %llu, fsdata: %p\n",
218 dentry->d_name.len, dentry->d_name.name,
219 (unsigned long long)parent_blkno, dl);
222 * Negative dentry. We ignore these for now.
224 * XXX: Could we can improve ocfs2_dentry_revalidate() by
225 * tracking these?
227 if (!inode)
228 return 0;
230 if (dl) {
231 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
232 " \"%.*s\": old parent: %llu, new: %llu\n",
233 dentry->d_name.len, dentry->d_name.name,
234 (unsigned long long)parent_blkno,
235 (unsigned long long)dl->dl_parent_blkno);
236 return 0;
239 alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
240 if (alias) {
242 * Great, an alias exists, which means we must have a
243 * dentry lock already. We can just grab the lock off
244 * the alias and add it to the list.
246 * We're depending here on the fact that this dentry
247 * was found and exists in the dcache and so must have
248 * a reference to the dentry_lock because we can't
249 * race creates. Final dput() cannot happen on it
250 * since we have it pinned, so our reference is safe.
252 dl = alias->d_fsdata;
253 mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
254 (unsigned long long)parent_blkno,
255 (unsigned long long)OCFS2_I(inode)->ip_blkno);
257 mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
258 " \"%.*s\": old parent: %llu, new: %llu\n",
259 dentry->d_name.len, dentry->d_name.name,
260 (unsigned long long)parent_blkno,
261 (unsigned long long)dl->dl_parent_blkno);
263 mlog(0, "Found: %s\n", dl->dl_lockres.l_name);
265 goto out_attach;
269 * There are no other aliases
271 dl = kmalloc(sizeof(*dl), GFP_NOFS);
272 if (!dl) {
273 ret = -ENOMEM;
274 mlog_errno(ret);
275 return ret;
278 dl->dl_count = 0;
280 * Does this have to happen below, for all attaches, in case
281 * the struct inode gets blown away by the downconvert thread?
283 dl->dl_inode = igrab(inode);
284 dl->dl_parent_blkno = parent_blkno;
285 ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
287 out_attach:
288 spin_lock(&dentry_attach_lock);
289 dentry->d_fsdata = dl;
290 dl->dl_count++;
291 spin_unlock(&dentry_attach_lock);
294 * This actually gets us our PRMODE level lock. From now on,
295 * we'll have a notification if one of these names is
296 * destroyed on another node.
298 ret = ocfs2_dentry_lock(dentry, 0);
299 if (!ret)
300 ocfs2_dentry_unlock(dentry, 0);
301 else
302 mlog_errno(ret);
305 * In case of error, manually free the allocation and do the iput().
306 * We need to do this because error here means no d_instantiate(),
307 * which means iput() will not be called during dput(dentry).
309 if (ret < 0 && !alias) {
310 ocfs2_lock_res_free(&dl->dl_lockres);
311 BUG_ON(dl->dl_count != 1);
312 spin_lock(&dentry_attach_lock);
313 dentry->d_fsdata = NULL;
314 spin_unlock(&dentry_attach_lock);
315 kfree(dl);
316 iput(inode);
319 dput(alias);
321 return ret;
324 DEFINE_SPINLOCK(dentry_list_lock);
326 /* We limit the number of dentry locks to drop in one go. We have
327 * this limit so that we don't starve other users of ocfs2_wq. */
328 #define DL_INODE_DROP_COUNT 64
330 /* Drop inode references from dentry locks */
331 static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count)
333 struct ocfs2_dentry_lock *dl;
335 spin_lock(&dentry_list_lock);
336 while (osb->dentry_lock_list && (drop_count < 0 || drop_count--)) {
337 dl = osb->dentry_lock_list;
338 osb->dentry_lock_list = dl->dl_next;
339 spin_unlock(&dentry_list_lock);
340 iput(dl->dl_inode);
341 kfree(dl);
342 spin_lock(&dentry_list_lock);
344 spin_unlock(&dentry_list_lock);
347 void ocfs2_drop_dl_inodes(struct work_struct *work)
349 struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
350 dentry_lock_work);
352 __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT);
354 * Don't queue dropping if umount is in progress. We flush the
355 * list in ocfs2_dismount_volume
357 spin_lock(&dentry_list_lock);
358 if (osb->dentry_lock_list &&
359 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
360 queue_work(ocfs2_wq, &osb->dentry_lock_work);
361 spin_unlock(&dentry_list_lock);
364 /* Flush the whole work queue */
365 void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
367 __ocfs2_drop_dl_inodes(osb, -1);
371 * ocfs2_dentry_iput() and friends.
373 * At this point, our particular dentry is detached from the inodes
374 * alias list, so there's no way that the locking code can find it.
376 * The interesting stuff happens when we determine that our lock needs
377 * to go away because this is the last subdir alias in the
378 * system. This function needs to handle a couple things:
380 * 1) Synchronizing lock shutdown with the downconvert threads. This
381 * is already handled for us via the lockres release drop function
382 * called in ocfs2_release_dentry_lock()
384 * 2) A race may occur when we're doing our lock shutdown and
385 * another process wants to create a new dentry lock. Right now we
386 * let them race, which means that for a very short while, this
387 * node might have two locks on a lock resource. This should be a
388 * problem though because one of them is in the process of being
389 * thrown out.
391 static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
392 struct ocfs2_dentry_lock *dl)
394 ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
395 ocfs2_lock_res_free(&dl->dl_lockres);
397 /* We leave dropping of inode reference to ocfs2_wq as that can
398 * possibly lead to inode deletion which gets tricky */
399 spin_lock(&dentry_list_lock);
400 if (!osb->dentry_lock_list &&
401 !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
402 queue_work(ocfs2_wq, &osb->dentry_lock_work);
403 dl->dl_next = osb->dentry_lock_list;
404 osb->dentry_lock_list = dl;
405 spin_unlock(&dentry_list_lock);
408 void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
409 struct ocfs2_dentry_lock *dl)
411 int unlock;
413 BUG_ON(dl->dl_count == 0);
415 spin_lock(&dentry_attach_lock);
416 dl->dl_count--;
417 unlock = !dl->dl_count;
418 spin_unlock(&dentry_attach_lock);
420 if (unlock)
421 ocfs2_drop_dentry_lock(osb, dl);
424 static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
426 struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
428 if (!dl) {
430 * No dentry lock is ok if we're disconnected or
431 * unhashed.
433 if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
434 !d_unhashed(dentry)) {
435 unsigned long long ino = 0ULL;
436 if (inode)
437 ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
438 mlog(ML_ERROR, "Dentry is missing cluster lock. "
439 "inode: %llu, d_flags: 0x%x, d_name: %.*s\n",
440 ino, dentry->d_flags, dentry->d_name.len,
441 dentry->d_name.name);
444 goto out;
447 mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n",
448 dentry->d_name.len, dentry->d_name.name,
449 dl->dl_count);
451 ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
453 out:
454 iput(inode);
458 * d_move(), but keep the locks in sync.
460 * When we are done, "dentry" will have the parent dir and name of
461 * "target", which will be thrown away.
463 * We manually update the lock of "dentry" if need be.
465 * "target" doesn't have it's dentry lock touched - we allow the later
466 * dput() to handle this for us.
468 * This is called during ocfs2_rename(), while holding parent
469 * directory locks. The dentries have already been deleted on other
470 * nodes via ocfs2_remote_dentry_delete().
472 * Normally, the VFS handles the d_move() for the file system, after
473 * the ->rename() callback. OCFS2 wants to handle this internally, so
474 * the new lock can be created atomically with respect to the cluster.
476 void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
477 struct inode *old_dir, struct inode *new_dir)
479 int ret;
480 struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
481 struct inode *inode = dentry->d_inode;
484 * Move within the same directory, so the actual lock info won't
485 * change.
487 * XXX: Is there any advantage to dropping the lock here?
489 if (old_dir == new_dir)
490 goto out_move;
492 ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
494 dentry->d_fsdata = NULL;
495 ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
496 if (ret)
497 mlog_errno(ret);
499 out_move:
500 d_move(dentry, target);
503 const struct dentry_operations ocfs2_dentry_ops = {
504 .d_revalidate = ocfs2_dentry_revalidate,
505 .d_iput = ocfs2_dentry_iput,