1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 only,
10 * as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License version 2 for more details (a copy is included
16 * in the LICENSE file that accompanied this code).
18 * You should have received a copy of the GNU General Public License
19 * version 2 along with this program; If not, see
20 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
29 * Copyright 2008 Sun Microsystems, Inc. All rights reserved
30 * Use is subject to license terms.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 #include <linux/sched.h>
39 #include <linux/smp_lock.h>
40 #include <linux/quotaops.h>
42 #define DEBUG_SUBSYSTEM S_LLITE
44 #include <obd_support.h>
45 #include <lustre_lite.h>
46 #include <lustre/lustre_idl.h>
47 #include <lustre_dlm.h>
48 #include <lustre_mdc.h>
49 //#include <lustre_ver.h>
50 //#include <lustre_version.h>
52 #include "llite_internal.h"
54 spinlock_t ll_lookup_lock = SPIN_LOCK_UNLOCKED;
56 /* should NOT be called with the dcache lock, see fs/dcache.c */
57 void ll_release(struct dentry *de)
59 struct ll_dentry_data *lld;
63 if (lld == NULL) { /* NFS copies the de->d_op methods (bug 4655) */
67 #ifndef HAVE_VFS_INTENT_PATCHES
69 ll_intent_release(lld->lld_it);
70 OBD_FREE(lld->lld_it, sizeof(*lld->lld_it));
73 LASSERT(lld->lld_cwd_count == 0);
74 LASSERT(lld->lld_mnt_count == 0);
75 OBD_FREE(de->d_fsdata, sizeof(*lld));
80 #ifdef DCACHE_LUSTRE_INVALID
81 /* Compare if two dentries are the same. Don't match if the existing dentry
82 * is marked DCACHE_LUSTRE_INVALID. Returns 1 if different, 0 if the same.
84 * This avoids a race where ll_lookup_it() instantiates a dentry, but we get
85 * an AST before calling d_revalidate_it(). The dentry still exists (marked
86 * INVALID) so d_lookup() matches it, but we have no lock on it (so
87 * lock_match() fails) and we spin around real_lookup(). */
88 int ll_dcompare(struct dentry *parent, struct qstr *d_name, struct qstr *name)
90 struct dentry *dchild;
93 if (d_name->len != name->len)
96 if (memcmp(d_name->name, name->name, name->len))
99 /* XXX: d_name must be in-dentry structure */
100 dchild = container_of(d_name, struct dentry, d_name); /* ugh */
101 if (dchild->d_flags & DCACHE_LUSTRE_INVALID) {
102 CDEBUG(D_DENTRY,"INVALID dentry %p not matched, was bug 3784\n",
111 /* should NOT be called with the dcache lock, see fs/dcache.c */
112 static int ll_ddelete(struct dentry *de)
116 #ifndef DCACHE_LUSTRE_INVALID
117 #define DCACHE_LUSTRE_INVALID 0
120 CDEBUG(D_DENTRY, "%s dentry %.*s (%p, parent %p, inode %p) %s%s\n",
121 (de->d_flags & DCACHE_LUSTRE_INVALID ? "deleting" : "keeping"),
122 de->d_name.len, de->d_name.name, de, de->d_parent, de->d_inode,
123 d_unhashed(de) ? "" : "hashed,",
124 list_empty(&de->d_subdirs) ? "" : "subdirs");
125 #if DCACHE_LUSTRE_INVALID == 0
126 #undef DCACHE_LUSTRE_INVALID
132 void ll_set_dd(struct dentry *de)
137 CDEBUG(D_DENTRY, "ldd on dentry %.*s (%p) parent %p inode %p refc %d\n",
138 de->d_name.len, de->d_name.name, de, de->d_parent, de->d_inode,
139 atomic_read(&de->d_count));
141 if (de->d_fsdata == NULL) {
142 struct ll_dentry_data *lld;
145 if (likely(lld != NULL)) {
146 cfs_waitq_init(&lld->lld_waitq);
148 if (likely(de->d_fsdata == NULL))
159 void ll_intent_drop_lock(struct lookup_intent *it)
161 struct lustre_handle *handle;
163 if (it->it_op && it->d.lustre.it_lock_mode) {
164 handle = (struct lustre_handle *)&it->d.lustre.it_lock_handle;
165 CDEBUG(D_DLMTRACE, "releasing lock with cookie "LPX64
166 " from it %p\n", handle->cookie, it);
167 ldlm_lock_decref(handle, it->d.lustre.it_lock_mode);
169 /* bug 494: intent_release may be called multiple times, from
170 * this thread and we don't want to double-decref this lock */
171 it->d.lustre.it_lock_mode = 0;
175 void ll_intent_release(struct lookup_intent *it)
179 CDEBUG(D_INFO, "intent %p released\n", it);
180 ll_intent_drop_lock(it);
181 #ifdef HAVE_VFS_INTENT_PATCHES
183 it->it_op_release = 0;
185 /* We are still holding extra reference on a request, need to free it */
186 if (it_disposition(it, DISP_ENQ_OPEN_REF))
187 ptlrpc_req_finished(it->d.lustre.it_data); /* ll_file_open */
188 if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
189 ptlrpc_req_finished(it->d.lustre.it_data);
190 if (it_disposition(it, DISP_ENQ_COMPLETE)) /* saved req from revalidate
192 ptlrpc_req_finished(it->d.lustre.it_data);
194 it->d.lustre.it_disposition = 0;
195 it->d.lustre.it_data = NULL;
199 /* Drop dentry if it is not used already, unhash otherwise.
200 Should be called with dcache lock held!
201 Returns: 1 if dentry was dropped, 0 if unhashed. */
202 int ll_drop_dentry(struct dentry *dentry)
205 if (atomic_read(&dentry->d_count) == 0) {
206 CDEBUG(D_DENTRY, "deleting dentry %.*s (%p) parent %p "
207 "inode %p\n", dentry->d_name.len,
208 dentry->d_name.name, dentry, dentry->d_parent,
212 unlock_dentry(dentry);
213 spin_unlock(&dcache_lock);
214 spin_unlock(&ll_lookup_lock);
216 spin_lock(&ll_lookup_lock);
217 spin_lock(&dcache_lock);
220 /* disconected dentry can not be find without lookup, because we
221 * not need his to unhash or mark invalid. */
222 if (dentry->d_flags & DCACHE_DISCONNECTED) {
223 unlock_dentry(dentry);
227 #ifdef DCACHE_LUSTRE_INVALID
228 if (!(dentry->d_flags & DCACHE_LUSTRE_INVALID)) {
230 if (!d_unhashed(dentry)) {
232 CDEBUG(D_DENTRY, "unhashing dentry %.*s (%p) parent %p "
233 "inode %p refc %d\n", dentry->d_name.len,
234 dentry->d_name.name, dentry, dentry->d_parent,
235 dentry->d_inode, atomic_read(&dentry->d_count));
236 /* actually we don't unhash the dentry, rather just
237 * mark it inaccessible for to __d_lookup(). otherwise
238 * sys_getcwd() could return -ENOENT -bzzz */
239 #ifdef DCACHE_LUSTRE_INVALID
240 dentry->d_flags |= DCACHE_LUSTRE_INVALID;
242 if (!dentry->d_inode || !S_ISDIR(dentry->d_inode->i_mode))
246 unlock_dentry(dentry);
250 void ll_unhash_aliases(struct inode *inode)
252 struct list_head *tmp, *head;
256 CERROR("unexpected NULL inode, tell phil\n");
260 CDEBUG(D_INODE, "marking dentries for ino %lu/%u(%p) invalid\n",
261 inode->i_ino, inode->i_generation, inode);
263 head = &inode->i_dentry;
264 spin_lock(&ll_lookup_lock);
265 spin_lock(&dcache_lock);
268 while ((tmp = tmp->next) != head) {
269 struct dentry *dentry = list_entry(tmp, struct dentry, d_alias);
271 CDEBUG(D_DENTRY, "dentry in drop %.*s (%p) parent %p "
272 "inode %p flags %d\n", dentry->d_name.len,
273 dentry->d_name.name, dentry, dentry->d_parent,
274 dentry->d_inode, dentry->d_flags);
276 if (dentry->d_name.len == 1 && dentry->d_name.name[0] == '/') {
277 CERROR("called on root (?) dentry=%p, inode=%p "
278 "ino=%lu\n", dentry, inode, inode->i_ino);
279 lustre_dump_dentry(dentry, 1);
280 libcfs_debug_dumpstack(NULL);
281 } else if (d_mountpoint(dentry)) {
282 /* For mountpoints we skip removal of the dentry
283 which happens solely because we have a lock on it
284 obtained when this dentry was not a mountpoint yet */
285 CDEBUG(D_DENTRY, "Skippind mountpoint dentry removal "
286 "%.*s (%p) parent %p\n",
289 dentry, dentry->d_parent);
294 if (ll_drop_dentry(dentry))
297 spin_unlock(&dcache_lock);
298 spin_unlock(&ll_lookup_lock);
303 int ll_revalidate_it_finish(struct ptlrpc_request *request,
304 struct lookup_intent *it,
313 if (it_disposition(it, DISP_LOOKUP_NEG))
316 rc = ll_prep_inode(&de->d_inode, request, NULL);
321 void ll_lookup_finish_locks(struct lookup_intent *it, struct dentry *dentry)
324 LASSERT(dentry != NULL);
326 if (it->d.lustre.it_lock_mode && dentry->d_inode != NULL) {
327 struct inode *inode = dentry->d_inode;
328 struct ll_sb_info *sbi = ll_i2sbi(dentry->d_inode);
330 CDEBUG(D_DLMTRACE, "setting l_data to inode %p (%lu/%u)\n",
331 inode, inode->i_ino, inode->i_generation);
332 md_set_lock_data(sbi->ll_md_exp, &it->d.lustre.it_lock_handle,
336 /* drop lookup or getattr locks immediately */
337 if (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR) {
338 /* on 2.6 there are situation when several lookups and
339 * revalidations may be requested during single operation.
340 * therefore, we don't release intent here -bzzz */
341 ll_intent_drop_lock(it);
345 void ll_frob_intent(struct lookup_intent **itp, struct lookup_intent *deft)
347 struct lookup_intent *it = *itp;
348 #ifdef HAVE_VFS_INTENT_PATCHES
350 LASSERTF(it->it_magic == INTENT_MAGIC,
351 "%p has bad intent magic: %x\n",
356 if (!it || it->it_op == IT_GETXATTR)
359 #ifdef HAVE_VFS_INTENT_PATCHES
360 it->it_op_release = ll_intent_release;
364 int ll_revalidate_it(struct dentry *de, int lookup_flags,
365 struct lookup_intent *it)
367 struct md_op_data *op_data;
368 struct ptlrpc_request *req = NULL;
369 struct lookup_intent lookup_it = { .it_op = IT_LOOKUP };
370 struct obd_export *exp;
371 struct inode *parent;
375 CDEBUG(D_VFSTRACE, "VFS Op:name=%s,intent=%s\n", de->d_name.name,
378 if (de->d_inode == NULL) {
379 /* We can only use negative dentries if this is stat or lookup,
380 for opens and stuff we do need to query server. */
381 /* If there is IT_CREAT in intent op set, then we must throw
382 away this negative dentry and actually do the request to
383 kernel to create whatever needs to be created (if possible)*/
384 if (it && (it->it_op & IT_CREAT))
387 #ifdef DCACHE_LUSTRE_INVALID
388 if (de->d_flags & DCACHE_LUSTRE_INVALID)
392 rc = ll_have_md_lock(de->d_parent->d_inode,
393 MDS_INODELOCK_UPDATE);
397 exp = ll_i2mdexp(de->d_inode);
399 /* Never execute intents for mount points.
400 * Attributes will be fixed up in ll_inode_revalidate_it */
401 if (d_mountpoint(de))
402 GOTO(out_sa, rc = 1);
404 /* Root of the lustre tree. Always valid.
405 * Attributes will be fixed up in ll_inode_revalidate_it */
406 if (de == de->d_sb->s_root)
407 GOTO(out_sa, rc = 1);
409 OBD_FAIL_TIMEOUT(OBD_FAIL_MDC_REVALIDATE_PAUSE, 5);
410 ll_frob_intent(&it, &lookup_it);
412 parent = de->d_parent->d_inode;
414 op_data = ll_prep_md_op_data(NULL, parent, de->d_inode,
415 de->d_name.name, de->d_name.len,
416 0, LUSTRE_OPC_ANY, NULL);
418 RETURN(PTR_ERR(op_data));
420 if ((it->it_op == IT_OPEN) && de->d_inode) {
421 struct inode *inode = de->d_inode;
422 struct ll_inode_info *lli = ll_i2info(inode);
423 struct obd_client_handle **och_p;
427 * We used to check for MDS_INODELOCK_OPEN here, but in fact
428 * just having LOOKUP lock is enough to justify inode is the
429 * same. And if inode is the same and we have suitable
430 * openhandle, then there is no point in doing another OPEN RPC
431 * just to throw away newly received openhandle. There are no
432 * security implications too, if file owner or access mode is
433 * change, LOOKUP lock is revoked.
437 if (it->it_flags & FMODE_WRITE) {
438 och_p = &lli->lli_mds_write_och;
439 och_usecount = &lli->lli_open_fd_write_count;
440 } else if (it->it_flags & FMODE_EXEC) {
441 och_p = &lli->lli_mds_exec_och;
442 och_usecount = &lli->lli_open_fd_exec_count;
444 och_p = &lli->lli_mds_read_och;
445 och_usecount = &lli->lli_open_fd_read_count;
447 /* Check for the proper lock. */
448 if (!ll_have_md_lock(inode, MDS_INODELOCK_LOOKUP))
450 down(&lli->lli_och_sem);
451 if (*och_p) { /* Everything is open already, do nothing */
452 /*(*och_usecount)++; Do not let them steal our open
453 handle from under us */
454 /* XXX The code above was my original idea, but in case
455 we have the handle, but we cannot use it due to later
456 checks (e.g. O_CREAT|O_EXCL flags set), nobody
457 would decrement counter increased here. So we just
458 hope the lock won't be invalidated in between. But
459 if it would be, we'll reopen the open request to
460 MDS later during file open path */
461 up(&lli->lli_och_sem);
462 ll_finish_md_op_data(op_data);
465 up(&lli->lli_och_sem);
469 if (it->it_op == IT_GETATTR)
470 first = ll_statahead_enter(de->d_parent->d_inode, &de, 0);
473 it->it_create_mode &= ~current->fs->umask;
474 it->it_flags |= O_CHECK_STALE;
475 rc = md_intent_lock(exp, op_data, NULL, 0, it,
477 &req, ll_md_blocking_ast, 0);
478 it->it_flags &= ~O_CHECK_STALE;
479 ll_finish_md_op_data(op_data);
480 if (it->it_op == IT_GETATTR && !first)
481 ll_statahead_exit(de, rc);
483 /* If req is NULL, then md_intent_lock only tried to do a lock match;
484 * if all was well, it will return 1 if it found locks, 0 otherwise. */
485 if (req == NULL && rc >= 0) {
493 CDEBUG(D_INFO, "ll_intent_lock: rc %d : it->it_status "
494 "%d\n", rc, it->d.lustre.it_status);
500 rc = ll_revalidate_it_finish(req, it, de);
502 if (rc != -ESTALE && rc != -ENOENT)
503 ll_intent_release(it);
507 if ((it->it_op & IT_OPEN) && de->d_inode &&
508 !S_ISREG(de->d_inode->i_mode) &&
509 !S_ISDIR(de->d_inode->i_mode)) {
510 ll_release_openhandle(de, it);
514 /* unfortunately ll_intent_lock may cause a callback and revoke our
516 spin_lock(&ll_lookup_lock);
517 spin_lock(&dcache_lock);
521 d_rehash_cond(de, 0);
522 spin_unlock(&dcache_lock);
523 spin_unlock(&ll_lookup_lock);
526 /* We do not free request as it may be reused during following lookup
527 * (see comment in mdc/mdc_locks.c::mdc_intent_lock()), request will
528 * be freed in ll_lookup_it or in ll_intent_release. But if
529 * request was not completed, we need to free it. (bug 5154, 9903) */
530 if (req != NULL && !it_disposition(it, DISP_ENQ_COMPLETE))
531 ptlrpc_req_finished(req);
533 #ifdef DCACHE_LUSTRE_INVALID
534 ll_unhash_aliases(de->d_inode);
535 /* done in ll_unhash_aliases()
536 dentry->d_flags |= DCACHE_LUSTRE_INVALID; */
538 /* We do not want d_invalidate to kill all child dentries too */
542 CDEBUG(D_DENTRY, "revalidated dentry %.*s (%p) parent %p "
543 "inode %p refc %d\n", de->d_name.len,
544 de->d_name.name, de, de->d_parent, de->d_inode,
545 atomic_read(&de->d_count));
546 ll_lookup_finish_locks(it, de);
547 #ifdef DCACHE_LUSTRE_INVALID
549 de->d_flags &= ~DCACHE_LUSTRE_INVALID;
556 * This part is here to combat evil-evil race in real_lookup on 2.6
557 * kernels. The race details are: We enter do_lookup() looking for some
558 * name, there is nothing in dcache for this name yet and d_lookup()
559 * returns NULL. We proceed to real_lookup(), and while we do this,
560 * another process does open on the same file we looking up (most simple
561 * reproducer), open succeeds and the dentry is added. Now back to
562 * us. In real_lookup() we do d_lookup() again and suddenly find the
563 * dentry, so we call d_revalidate on it, but there is no lock, so
564 * without this code we would return 0, but unpatched real_lookup just
565 * returns -ENOENT in such a case instead of retrying the lookup. Once
566 * this is dealt with in real_lookup(), all of this ugly mess can go and
567 * we can just check locks in ->d_revalidate without doing any RPCs
571 if (it != &lookup_it) {
572 /* MDS_INODELOCK_UPDATE needed for IT_GETATTR case. */
573 if (it->it_op == IT_GETATTR)
574 lookup_it.it_op = IT_GETATTR;
575 ll_lookup_finish_locks(it, de);
579 /* Do real lookup here. */
580 op_data = ll_prep_md_op_data(NULL, parent, NULL, de->d_name.name,
581 de->d_name.len, 0, (it->it_op & IT_CREAT ?
583 LUSTRE_OPC_ANY), NULL);
585 RETURN(PTR_ERR(op_data));
587 rc = md_intent_lock(exp, op_data, NULL, 0, it, 0, &req,
588 ll_md_blocking_ast, 0);
590 struct mdt_body *mdt_body;
591 struct lu_fid fid = {.f_seq = 0, .f_oid = 0, .f_ver = 0};
592 mdt_body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
595 fid = *ll_inode2fid(de->d_inode);
597 /* see if we got same inode, if not - return error */
598 if (lu_fid_eq(&fid, &mdt_body->fid1)) {
599 ll_finish_md_op_data(op_data);
601 goto revalidate_finish;
603 ll_intent_release(it);
605 ll_finish_md_op_data(op_data);
610 * For rc == 1 case, should not return directly to prevent losing
611 * statahead windows; for rc == 0 case, the "lookup" will be done later.
613 if (it && it->it_op == IT_GETATTR && rc == 1) {
614 first = ll_statahead_enter(de->d_parent->d_inode, &de, 0);
616 ll_statahead_exit(de, rc);
622 /*static*/ void ll_pin(struct dentry *de, struct vfsmount *mnt, int flag)
624 struct inode *inode= de->d_inode;
625 struct ll_sb_info *sbi = ll_i2sbi(inode);
626 struct ll_dentry_data *ldd = ll_d2d(de);
627 struct obd_client_handle *handle;
634 /* Strictly speaking this introduces an additional race: the
635 * increments should wait until the rpc has returned.
636 * However, given that at present the function is void, this
638 if (flag == 1 && (++ldd->lld_mnt_count) > 1) {
644 if (flag == 0 && (++ldd->lld_cwd_count) > 1) {
651 handle = (flag) ? &ldd->lld_mnt_och : &ldd->lld_cwd_och;
652 oc = ll_mdscapa_get(inode);
653 rc = obd_pin(sbi->ll_md_exp, ll_inode2fid(inode), oc, handle, flag);
657 memset(handle, 0, sizeof(*handle));
659 ldd->lld_cwd_count--;
661 ldd->lld_mnt_count--;
669 /*static*/ void ll_unpin(struct dentry *de, struct vfsmount *mnt, int flag)
671 struct ll_sb_info *sbi = ll_i2sbi(de->d_inode);
672 struct ll_dentry_data *ldd = ll_d2d(de);
673 struct obd_client_handle handle;
679 /* Strictly speaking this introduces an additional race: the
680 * increments should wait until the rpc has returned.
681 * However, given that at present the function is void, this
683 handle = (flag) ? ldd->lld_mnt_och : ldd->lld_cwd_och;
684 if (handle.och_magic != OBD_CLIENT_HANDLE_MAGIC) {
685 /* the "pin" failed */
692 count = --ldd->lld_mnt_count;
694 count = --ldd->lld_cwd_count;
702 rc = obd_unpin(sbi->ll_md_exp, &handle, flag);
707 #ifdef HAVE_VFS_INTENT_PATCHES
708 static int ll_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
713 if (nd && nd->flags & LOOKUP_LAST && !(nd->flags & LOOKUP_LINK_NOTLAST))
714 rc = ll_revalidate_it(dentry, nd->flags, &nd->intent);
716 rc = ll_revalidate_it(dentry, 0, NULL);
721 int ll_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
726 if (nd && !(nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))) {
727 struct lookup_intent *it;
728 it = ll_convert_intent(&nd->intent.open, nd->flags);
731 if (it->it_op == (IT_OPEN|IT_CREAT))
732 if (nd->intent.open.flags & O_EXCL) {
733 CDEBUG(D_VFSTRACE, "create O_EXCL, returning 0\n");
738 rc = ll_revalidate_it(dentry, nd->flags, it);
740 if (rc && (nd->flags & LOOKUP_OPEN) &&
741 it_disposition(it, DISP_OPEN_OPEN)) {/*Open*/
742 #ifdef HAVE_FILE_IN_STRUCT_INTENT
743 // XXX Code duplication with ll_lookup_nd
744 if (S_ISFIFO(dentry->d_inode->i_mode)) {
745 // We cannot call open here as it would
748 (struct ptlrpc_request *)
749 it->d.lustre.it_data);
753 nd->intent.open.file->private_data = it;
754 filp = lookup_instantiate_filp(nd, dentry,NULL);
755 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17))
756 /* 2.6.1[456] have a bug in open_namei() that forgets to check
757 * nd->intent.open.file for error, so we need to return it as lookup's result
764 ll_release_openhandle(dentry, it);
765 #endif /* HAVE_FILE_IN_STRUCT_INTENT */
767 if (!rc && (nd->flags & LOOKUP_CREATE) &&
768 it_disposition(it, DISP_OPEN_CREATE)) {
769 /* We created something but we may only return
770 * negative dentry here, so save request in dentry,
771 * if lookup will be called later on, it will
772 * pick the request, otherwise it would be freed
774 ll_d2d(dentry)->lld_it = it;
775 it = NULL; /* avoid freeing */
780 ll_intent_release(it);
781 OBD_FREE(it, sizeof(*it));
784 rc = ll_revalidate_it(dentry, 0, NULL);
791 struct dentry_operations ll_d_ops = {
792 .d_revalidate = ll_revalidate_nd,
793 .d_release = ll_release,
794 .d_delete = ll_ddelete,
795 #ifdef DCACHE_LUSTRE_INVALID
796 .d_compare = ll_dcompare,
804 static int ll_fini_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
811 struct dentry_operations ll_fini_d_ops = {
812 .d_revalidate = ll_fini_revalidate_nd,
813 .d_release = ll_release,
817 * It is for the following race condition:
818 * When someone (maybe statahead thread) adds the dentry to the dentry hash
819 * table, the dentry's "d_op" maybe NULL, at the same time, another (maybe
820 * "ls -l") process finds such dentry by "do_lookup()" without "do_revalidate()"
821 * called. It causes statahead window lost, and maybe other issues. --Fan Yong
823 static int ll_init_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
825 struct l_wait_info lwi = { 0 };
826 struct ll_dentry_data *lld;
830 lld = ll_d2d(dentry);
831 if (unlikely(lld == NULL))
834 l_wait_event(lld->lld_waitq, dentry->d_op != &ll_init_d_ops, &lwi);
835 if (likely(dentry->d_op == &ll_d_ops))
836 RETURN(ll_revalidate_nd(dentry, nd));
838 RETURN(dentry->d_op == &ll_fini_d_ops ? 0 : -EINVAL);
841 struct dentry_operations ll_init_d_ops = {
842 .d_revalidate = ll_init_revalidate_nd,
843 .d_release = ll_release,