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[fs/lustre-release.git] / lustre / llite / dcache.c
index 13867b6..0f7c7e6 100644 (file)
@@ -1,22 +1,37 @@
 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
  * vim:expandtab:shiftwidth=8:tabstop=8:
  *
- *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
+ * GPL HEADER START
  *
- *   This file is part of Lustre, http://www.lustre.org.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
- *   Lustre is free software; you can redistribute it and/or
- *   modify it under the terms of version 2 of the GNU General Public
- *   License as published by the Free Software Foundation.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
  *
- *   Lustre is distributed in the hope that it will be useful,
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *   GNU General Public License for more details.
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
  *
- *   You should have received a copy of the GNU General Public License
- *   along with Lustre; if not, write to the Free Software
- *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright  2008 Sun Microsystems, Inc. All rights reserved
+ * Use is subject to license terms.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
 #include <linux/fs.h>
 
 #define DEBUG_SUBSYSTEM S_LLITE
 
-#include <linux/obd_support.h>
-#include <linux/lustre_lite.h>
-#include <linux/lustre_idl.h>
-#include <linux/lustre_dlm.h>
-#include <linux/lustre_version.h>
+#include <obd_support.h>
+#include <lustre_lite.h>
+#include <lustre/lustre_idl.h>
+#include <lustre_dlm.h>
+#include <lustre_mdc.h>
+//#include <lustre_ver.h>
+//#include <lustre_version.h>
 
 #include "llite_internal.h"
 
+spinlock_t ll_lookup_lock = SPIN_LOCK_UNLOCKED;
+
 /* should NOT be called with the dcache lock, see fs/dcache.c */
 static void ll_release(struct dentry *de)
 {
@@ -41,24 +60,72 @@ static void ll_release(struct dentry *de)
         ENTRY;
         LASSERT(de != NULL);
         lld = ll_d2d(de);
-        LASSERT(lld != NULL);
+        if (lld == NULL) { /* NFS copies the de->d_op methods (bug 4655) */
+                EXIT;
+                return;
+        }
+#ifndef HAVE_VFS_INTENT_PATCHES
+        if (lld->lld_it) {
+                ll_intent_release(lld->lld_it);
+                OBD_FREE(lld->lld_it, sizeof(*lld->lld_it));
+        }
+#endif
         LASSERT(lld->lld_cwd_count == 0);
         LASSERT(lld->lld_mnt_count == 0);
-        OBD_FREE(de->d_fsdata, sizeof(struct ll_dentry_data));
+        OBD_FREE(de->d_fsdata, sizeof(*lld));
 
         EXIT;
 }
 
+#ifdef DCACHE_LUSTRE_INVALID
+/* Compare if two dentries are the same.  Don't match if the existing dentry
+ * is marked DCACHE_LUSTRE_INVALID.  Returns 1 if different, 0 if the same.
+ *
+ * This avoids a race where ll_lookup_it() instantiates a dentry, but we get
+ * an AST before calling d_revalidate_it().  The dentry still exists (marked
+ * INVALID) so d_lookup() matches it, but we have no lock on it (so
+ * lock_match() fails) and we spin around real_lookup(). */
+int ll_dcompare(struct dentry *parent, struct qstr *d_name, struct qstr *name)
+{
+        struct dentry *dchild;
+        ENTRY;
+
+        if (d_name->len != name->len)
+                RETURN(1);
+
+        if (memcmp(d_name->name, name->name, name->len))
+                RETURN(1);
+
+        /* XXX: d_name must be in-dentry structure */
+        dchild = container_of(d_name, struct dentry, d_name); /* ugh */
+        if (dchild->d_flags & DCACHE_LUSTRE_INVALID) {
+                CDEBUG(D_DENTRY,"INVALID dentry %p not matched, was bug 3784\n",
+                       dchild);
+                RETURN(1);
+        }
+
+        RETURN(0);
+}
+#endif
+
 /* should NOT be called with the dcache lock, see fs/dcache.c */
 static int ll_ddelete(struct dentry *de)
 {
         ENTRY;
         LASSERT(de);
-        CDEBUG(D_DENTRY, "%s dentry %*s (%p, parent %p, inode %p) %s%s\n",
-               (de->d_flags & DCACHE_LUSTRE_INVALID ? "keeping" : "deleting"),
+#ifndef DCACHE_LUSTRE_INVALID
+#define DCACHE_LUSTRE_INVALID 0
+#endif
+
+        CDEBUG(D_DENTRY, "%s dentry %.*s (%p, parent %p, inode %p) %s%s\n",
+               (de->d_flags & DCACHE_LUSTRE_INVALID ? "deleting" : "keeping"),
                de->d_name.len, de->d_name.name, de, de->d_parent, de->d_inode,
                d_unhashed(de) ? "" : "hashed,",
                list_empty(&de->d_subdirs) ? "" : "subdirs");
+#if DCACHE_LUSTRE_INVALID == 0
+#undef DCACHE_LUSTRE_INVALID
+#endif
+
         RETURN(0);
 }
 
@@ -67,14 +134,23 @@ void ll_set_dd(struct dentry *de)
         ENTRY;
         LASSERT(de != NULL);
 
-        CDEBUG(D_DENTRY, "ldd on dentry %*s (%p) parent %p inode %p refc %d\n",
+        CDEBUG(D_DENTRY, "ldd on dentry %.*s (%p) parent %p inode %p refc %d\n",
                de->d_name.len, de->d_name.name, de, de->d_parent, de->d_inode,
                atomic_read(&de->d_count));
-        lock_kernel();
+
         if (de->d_fsdata == NULL) {
-                OBD_ALLOC(de->d_fsdata, sizeof(struct ll_dentry_data));
+                struct ll_dentry_data *lld;
+
+                OBD_ALLOC_PTR(lld);
+                if (likely(lld != NULL)) {
+                        lock_dentry(de);
+                        if (likely(de->d_fsdata == NULL))
+                                de->d_fsdata = lld;
+                        else
+                                OBD_FREE_PTR(lld);
+                        unlock_dentry(de);
+                }
         }
-        unlock_kernel();
 
         EXIT;
 }
@@ -99,18 +175,80 @@ void ll_intent_release(struct lookup_intent *it)
 {
         ENTRY;
 
+        CDEBUG(D_INFO, "intent %p released\n", it);
         ll_intent_drop_lock(it);
+#ifdef HAVE_VFS_INTENT_PATCHES
         it->it_magic = 0;
         it->it_op_release = 0;
+#endif
+        /* We are still holding extra reference on a request, need to free it */
+        if (it_disposition(it, DISP_ENQ_OPEN_REF))
+                 ptlrpc_req_finished(it->d.lustre.it_data); /* ll_file_open */
+        if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
+                ptlrpc_req_finished(it->d.lustre.it_data);
+        if (it_disposition(it, DISP_ENQ_COMPLETE)) /* saved req from revalidate
+                                                    * to lookup */
+                ptlrpc_req_finished(it->d.lustre.it_data);
+
         it->d.lustre.it_disposition = 0;
         it->d.lustre.it_data = NULL;
         EXIT;
 }
 
+/* Drop dentry if it is not used already, unhash otherwise.
+   Should be called with dcache lock held!
+   Returns: 1 if dentry was dropped, 0 if unhashed. */
+int ll_drop_dentry(struct dentry *dentry)
+{
+        lock_dentry(dentry);
+        if (atomic_read(&dentry->d_count) == 0) {
+                CDEBUG(D_DENTRY, "deleting dentry %.*s (%p) parent %p "
+                       "inode %p\n", dentry->d_name.len,
+                       dentry->d_name.name, dentry, dentry->d_parent,
+                       dentry->d_inode);
+                dget_locked(dentry);
+                __d_drop(dentry);
+                unlock_dentry(dentry);
+                spin_unlock(&dcache_lock);
+                spin_unlock(&ll_lookup_lock);
+                dput(dentry);
+                spin_lock(&ll_lookup_lock);
+                spin_lock(&dcache_lock);
+                return 1;
+        }
+        /* disconected dentry can not be find without lookup, because we
+         * not need his to unhash or mark invalid. */
+        if (dentry->d_flags & DCACHE_DISCONNECTED) {
+                unlock_dentry(dentry);
+                RETURN (0);
+        }
+
+#ifdef DCACHE_LUSTRE_INVALID
+        if (!(dentry->d_flags & DCACHE_LUSTRE_INVALID)) {
+#else
+        if (!d_unhashed(dentry)) {
+#endif
+                CDEBUG(D_DENTRY, "unhashing dentry %.*s (%p) parent %p "
+                       "inode %p refc %d\n", dentry->d_name.len,
+                       dentry->d_name.name, dentry, dentry->d_parent,
+                       dentry->d_inode, atomic_read(&dentry->d_count));
+                /* actually we don't unhash the dentry, rather just
+                 * mark it inaccessible for to __d_lookup(). otherwise
+                 * sys_getcwd() could return -ENOENT -bzzz */
+#ifdef DCACHE_LUSTRE_INVALID
+                dentry->d_flags |= DCACHE_LUSTRE_INVALID;
+#endif
+                if (!dentry->d_inode || !S_ISDIR(dentry->d_inode->i_mode))
+                        __d_drop(dentry);
+
+        }
+        unlock_dentry(dentry);
+        return 0;
+}
+
 void ll_unhash_aliases(struct inode *inode)
 {
         struct list_head *tmp, *head;
-        struct ll_sb_info *sbi;
         ENTRY;
 
         if (inode == NULL) {
@@ -121,45 +259,50 @@ void ll_unhash_aliases(struct inode *inode)
         CDEBUG(D_INODE, "marking dentries for ino %lu/%u(%p) invalid\n",
                inode->i_ino, inode->i_generation, inode);
 
-        sbi = ll_i2sbi(inode);
         head = &inode->i_dentry;
-restart:
+        spin_lock(&ll_lookup_lock);
         spin_lock(&dcache_lock);
+restart:
         tmp = head;
         while ((tmp = tmp->next) != head) {
                 struct dentry *dentry = list_entry(tmp, struct dentry, d_alias);
-                if (atomic_read(&dentry->d_count) == 0) {
-                        CDEBUG(D_DENTRY, "deleting dentry %*s (%p) parent %p "
-                               "inode %p\n", dentry->d_name.len,
-                               dentry->d_name.name, dentry, dentry->d_parent,
-                               dentry->d_inode);
-                        dget_locked(dentry);
-                        __d_drop(dentry);
-                        spin_unlock(&dcache_lock);
-                        dput(dentry);
-                        goto restart;
-                } else if (!(dentry->d_flags & DCACHE_LUSTRE_INVALID)) {
-                        CDEBUG(D_DENTRY, "unhashing dentry %*s (%p) parent %p "
-                               "inode %p refc %d\n", dentry->d_name.len,
-                               dentry->d_name.name, dentry, dentry->d_parent,
-                               dentry->d_inode, atomic_read(&dentry->d_count));
-                        hlist_del_init(&dentry->d_hash);
-                        dentry->d_flags |= DCACHE_LUSTRE_INVALID;
-                        hlist_add_head(&dentry->d_hash,
-                                       &sbi->ll_orphan_dentry_list);
+
+                CDEBUG(D_DENTRY, "dentry in drop %.*s (%p) parent %p "
+                       "inode %p flags %d\n", dentry->d_name.len,
+                       dentry->d_name.name, dentry, dentry->d_parent,
+                       dentry->d_inode, dentry->d_flags);
+
+                if (dentry->d_name.len == 1 && dentry->d_name.name[0] == '/') {
+                        CERROR("called on root (?) dentry=%p, inode=%p "
+                               "ino=%lu\n", dentry, inode, inode->i_ino);
+                        lustre_dump_dentry(dentry, 1);
+                        libcfs_debug_dumpstack(NULL);
+                } else if (d_mountpoint(dentry)) {
+                        /* For mountpoints we skip removal of the dentry
+                           which happens solely because we have a lock on it
+                           obtained when this dentry was not a mountpoint yet */
+                        CDEBUG(D_DENTRY, "Skippind mountpoint dentry removal "
+                                         "%.*s (%p) parent %p\n",
+                                          dentry->d_name.len,
+                                          dentry->d_name.name,
+                                          dentry, dentry->d_parent);
+
+                        continue;
                 }
+
+                if (ll_drop_dentry(dentry))
+                          goto restart;
         }
         spin_unlock(&dcache_lock);
+        spin_unlock(&ll_lookup_lock);
+
         EXIT;
 }
 
-extern struct dentry *ll_find_alias(struct inode *, struct dentry *);
-
-static int revalidate_it_finish(struct ptlrpc_request *request, 
-                                int offset, struct lookup_intent *it,
-                                struct dentry *de)
+int ll_revalidate_it_finish(struct ptlrpc_request *request,
+                            struct lookup_intent *it,
+                            struct dentry *de)
 {
-        struct ll_sb_info *sbi;
         int rc = 0;
         ENTRY;
 
@@ -169,9 +312,7 @@ static int revalidate_it_finish(struct ptlrpc_request *request,
         if (it_disposition(it, DISP_LOOKUP_NEG))
                 RETURN(-ENOENT);
 
-        sbi = ll_i2sbi(de->d_inode);
-        rc = ll_prep_inode(sbi->ll_osc_exp, sbi->ll_mdc_exp,
-                           &de->d_inode, request, offset, NULL);
+        rc = ll_prep_inode(&de->d_inode, request, NULL);
 
         RETURN(rc);
 }
@@ -183,156 +324,311 @@ void ll_lookup_finish_locks(struct lookup_intent *it, struct dentry *dentry)
 
         if (it->d.lustre.it_lock_mode && dentry->d_inode != NULL) {
                 struct inode *inode = dentry->d_inode;
+                struct ll_sb_info *sbi = ll_i2sbi(dentry->d_inode);
+
                 CDEBUG(D_DLMTRACE, "setting l_data to inode %p (%lu/%u)\n",
                        inode, inode->i_ino, inode->i_generation);
-                mdc_set_lock_data(NULL, &it->d.lustre.it_lock_handle, inode);
+                md_set_lock_data(sbi->ll_md_exp, &it->d.lustre.it_lock_handle,
+                                 inode);
         }
 
         /* drop lookup or getattr locks immediately */
         if (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR) {
-#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
                 /* on 2.6 there are situation when several lookups and
                  * revalidations may be requested during single operation.
                  * therefore, we don't release intent here -bzzz */
                 ll_intent_drop_lock(it);
-#else
-                ll_intent_release(it);
-#endif
         }
 }
 
 void ll_frob_intent(struct lookup_intent **itp, struct lookup_intent *deft)
 {
         struct lookup_intent *it = *itp;
-#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
-        if (it && it->it_magic != INTENT_MAGIC) {
-                CERROR("WARNING: uninitialized intent\n");
-                LBUG();
+#ifdef HAVE_VFS_INTENT_PATCHES
+        if (it) {
+                LASSERTF(it->it_magic == INTENT_MAGIC,
+                         "%p has bad intent magic: %x\n",
+                         it, it->it_magic);
         }
-        if (it && (it->it_op == IT_GETATTR || it->it_op == 0))
-                it->it_op = IT_LOOKUP;
 #endif
 
         if (!it || it->it_op == IT_GETXATTR)
                 it = *itp = deft;
 
+#ifdef HAVE_VFS_INTENT_PATCHES
         it->it_op_release = ll_intent_release;
+#endif
 }
 
-int ll_revalidate_it(struct dentry *de, int flags, struct nameidata *nd,
+int ll_revalidate_it(struct dentry *de, int lookup_flags,
                      struct lookup_intent *it)
 {
-        int rc;
-        struct ll_fid pfid, cfid;
-        struct it_cb_data icbd;
+        struct md_op_data *op_data;
         struct ptlrpc_request *req = NULL;
         struct lookup_intent lookup_it = { .it_op = IT_LOOKUP };
         struct obd_export *exp;
+        struct inode *parent;
+        int rc, first = 0;
 
         ENTRY;
         CDEBUG(D_VFSTRACE, "VFS Op:name=%s,intent=%s\n", de->d_name.name,
                LL_IT2STR(it));
 
-        /* Cached negative dentries are unsafe for now - look them up again */
-        if (de->d_inode == NULL)
-                RETURN(0);
+        if (de->d_inode == NULL) {
+                /* We can only use negative dentries if this is stat or lookup,
+                   for opens and stuff we do need to query server. */
+                /* If there is IT_CREAT in intent op set, then we must throw
+                   away this negative dentry and actually do the request to
+                   kernel to create whatever needs to be created (if possible)*/
+                if (it && (it->it_op & IT_CREAT))
+                        RETURN(0);
+
+#ifdef DCACHE_LUSTRE_INVALID
+                if (de->d_flags & DCACHE_LUSTRE_INVALID)
+                        RETURN(0);
+#endif
 
-        CDEBUG(D_INODE, "revalidate 0x%p: %*s -> %lu/%lu\n",
-                        de, de->d_name.len, de->d_name.name,
-                        (unsigned long) de->d_inode->i_ino,
-                        (unsigned long) de->d_inode->i_generation);
+                rc = ll_have_md_lock(de->d_parent->d_inode,
+                                     MDS_INODELOCK_UPDATE);
+                GOTO(out_sa, rc);
+        }
 
-        exp = ll_i2mdcexp(de->d_inode);
-        ll_inode2fid(&pfid, de->d_parent->d_inode);
-        ll_inode2fid(&cfid, de->d_inode);
-        icbd.icbd_parent = de->d_parent->d_inode;
-        icbd.icbd_childp = &de;
+        exp = ll_i2mdexp(de->d_inode);
 
         /* Never execute intents for mount points.
          * Attributes will be fixed up in ll_inode_revalidate_it */
         if (d_mountpoint(de))
-                RETURN(1);
+                GOTO(out_sa, rc = 1);
 
-        if (nd != NULL)
-                nd->mnt->mnt_last_used = jiffies;
+        /* Root of the lustre tree. Always valid.
+         * Attributes will be fixed up in ll_inode_revalidate_it */
+        if (de == de->d_sb->s_root)
+                GOTO(out_sa, rc = 1);
 
+        OBD_FAIL_TIMEOUT(OBD_FAIL_MDC_REVALIDATE_PAUSE, 5);
         ll_frob_intent(&it, &lookup_it);
         LASSERT(it);
-
-        if (it->it_op == IT_GETATTR) { /* We need to check for LOOKUP lock
-                                          as well */
-                rc = md_intent_lock(exp, &pfid, de->d_name.name,
-                                    de->d_name.len, NULL, 0, &cfid, &lookup_it,
-                                    flags, &req, ll_mdc_blocking_ast);
-                /* If there was no lookup lock, no point in even checking for
-                   UPDATE lock */
-                if (!rc) {
-                        it = &lookup_it;
-                        GOTO(out, rc);
+        parent = de->d_parent->d_inode;
+
+        op_data = ll_prep_md_op_data(NULL, parent, de->d_inode,
+                                     de->d_name.name, de->d_name.len,
+                                     0, LUSTRE_OPC_ANY, NULL);
+        if (IS_ERR(op_data))
+                RETURN(PTR_ERR(op_data));
+
+        if ((it->it_op == IT_OPEN) && de->d_inode) {
+                struct inode *inode = de->d_inode;
+                struct ll_inode_info *lli = ll_i2info(inode);
+                struct obd_client_handle **och_p;
+                __u64 *och_usecount;
+
+                /*
+                 * We used to check for MDS_INODELOCK_OPEN here, but in fact
+                 * just having LOOKUP lock is enough to justify inode is the
+                 * same. And if inode is the same and we have suitable
+                 * openhandle, then there is no point in doing another OPEN RPC
+                 * just to throw away newly received openhandle.  There are no
+                 * security implications too, if file owner or access mode is
+                 * change, LOOKUP lock is revoked.
+                 */
+
+
+                if (it->it_flags & FMODE_WRITE) {
+                        och_p = &lli->lli_mds_write_och;
+                        och_usecount = &lli->lli_open_fd_write_count;
+                } else if (it->it_flags & FMODE_EXEC) {
+                        och_p = &lli->lli_mds_exec_och;
+                        och_usecount = &lli->lli_open_fd_exec_count;
+                } else {
+                        och_p = &lli->lli_mds_read_och;
+                        och_usecount = &lli->lli_open_fd_read_count;
                 }
-                if (it_disposition(&lookup_it, DISP_LOOKUP_NEG)) {
-                        ll_intent_release(&lookup_it);
-                        it = &lookup_it;
-                        GOTO(out, rc = 0);
+                /* Check for the proper lock. */
+                if (!ll_have_md_lock(inode, MDS_INODELOCK_LOOKUP))
+                        goto do_lock;
+                down(&lli->lli_och_sem);
+                if (*och_p) { /* Everything is open already, do nothing */
+                        /*(*och_usecount)++;  Do not let them steal our open
+                          handle from under us */
+                        /* XXX The code above was my original idea, but in case
+                           we have the handle, but we cannot use it due to later
+                           checks (e.g. O_CREAT|O_EXCL flags set), nobody
+                           would decrement counter increased here. So we just
+                           hope the lock won't be invalidated in between. But
+                           if it would be, we'll reopen the open request to
+                           MDS later during file open path */
+                        up(&lli->lli_och_sem);
+                        ll_finish_md_op_data(op_data);
+                        RETURN(1);
+                } else {
+                        up(&lli->lli_och_sem);
                 }
-
-                if (req)
-                        ptlrpc_req_finished(req);
-                req = NULL;
-                ll_lookup_finish_locks(&lookup_it, de);
         }
 
-        rc = md_intent_lock(exp, &pfid, de->d_name.name, de->d_name.len,
-                            NULL, 0, &cfid, it, flags, &req,
-                            ll_mdc_blocking_ast);
-        /* If req is NULL, then mdc_intent_lock only tried to do a lock match;
+        if (it->it_op == IT_GETATTR)
+                first = ll_statahead_enter(de->d_parent->d_inode, &de, 0);
+
+do_lock:
+        it->it_create_mode &= ~current->fs->umask;
+        it->it_flags |= O_CHECK_STALE;
+        rc = md_intent_lock(exp, op_data, NULL, 0, it,
+                            lookup_flags,
+                            &req, ll_md_blocking_ast, 0);
+        it->it_flags &= ~O_CHECK_STALE;
+        ll_finish_md_op_data(op_data);
+        if (it->it_op == IT_GETATTR && !first)
+                /* If there are too many locks on client-side, then some
+                 * locks taken by statahead maybe dropped automatically
+                 * before the real "revalidate" using them. */
+                ll_statahead_exit(de, req == NULL ? rc : 0);
+        else if (first == -EEXIST)
+                ll_statahead_mark(de);
+
+        /* If req is NULL, then md_intent_lock only tried to do a lock match;
          * if all was well, it will return 1 if it found locks, 0 otherwise. */
-        if (req == NULL && rc >= 0)
+        if (req == NULL && rc >= 0) {
+                if (!rc)
+                        goto do_lookup;
                 GOTO(out, rc);
+        }
 
         if (rc < 0) {
                 if (rc != -ESTALE) {
                         CDEBUG(D_INFO, "ll_intent_lock: rc %d : it->it_status "
                                "%d\n", rc, it->d.lustre.it_status);
+                } else {
+#ifndef HAVE_VFS_INTENT_PATCHES
+                        if (it_disposition(it, DISP_OPEN_OPEN) &&
+                            !it_open_error(DISP_OPEN_OPEN, it))
+                                /* server have valid open - close file first*/
+                                ll_release_openhandle(de, it);
+#endif
                 }
                 GOTO(out, rc = 0);
         }
 
-        rc = revalidate_it_finish(req, 1, it, de);
+revalidate_finish:
+        rc = ll_revalidate_it_finish(req, it, de);
         if (rc != 0) {
-                ll_intent_release(it);
+                if (rc != -ESTALE && rc != -ENOENT)
+                        ll_intent_release(it);
                 GOTO(out, rc = 0);
         }
+
+        if ((it->it_op & IT_OPEN) && de->d_inode &&
+            !S_ISREG(de->d_inode->i_mode) &&
+            !S_ISDIR(de->d_inode->i_mode)) {
+                ll_release_openhandle(de, it);
+        }
         rc = 1;
 
         /* unfortunately ll_intent_lock may cause a callback and revoke our
-           dentry */
+         * dentry */
+        spin_lock(&ll_lookup_lock);
         spin_lock(&dcache_lock);
-        hlist_del_init(&de->d_hash);
-        __d_rehash(de, 0);
+        lock_dentry(de);
+        __d_drop(de);
+        unlock_dentry(de);
+        d_rehash_cond(de, 0);
         spin_unlock(&dcache_lock);
-
-        GOTO(out, rc);
- out:
-        if (req != NULL && rc == 1)
+        spin_unlock(&ll_lookup_lock);
+
+out:
+        /* We do not free request as it may be reused during following lookup
+         * (see comment in mdc/mdc_locks.c::mdc_intent_lock()), request will
+         * be freed in ll_lookup_it or in ll_intent_release. But if
+         * request was not completed, we need to free it. (bug 5154, 9903) */
+        if (req != NULL && !it_disposition(it, DISP_ENQ_COMPLETE))
                 ptlrpc_req_finished(req);
         if (rc == 0) {
+#ifdef DCACHE_LUSTRE_INVALID
                 ll_unhash_aliases(de->d_inode);
-                return rc;
+                /* done in ll_unhash_aliases()
+                   dentry->d_flags |= DCACHE_LUSTRE_INVALID; */
+#else
+                /* We do not want d_invalidate to kill all child dentries too */
+                d_drop(de);
+#endif
+        } else {
+                CDEBUG(D_DENTRY, "revalidated dentry %.*s (%p) parent %p "
+                       "inode %p refc %d\n", de->d_name.len,
+                       de->d_name.name, de, de->d_parent, de->d_inode,
+                       atomic_read(&de->d_count));
+                ll_lookup_finish_locks(it, de);
+#ifdef DCACHE_LUSTRE_INVALID
+                lock_dentry(de);
+                de->d_flags &= ~DCACHE_LUSTRE_INVALID;
+                unlock_dentry(de);
+#endif
+        }
+        RETURN(rc);
+
+        /*
+         * This part is here to combat evil-evil race in real_lookup on 2.6
+         * kernels.  The race details are: We enter do_lookup() looking for some
+         * name, there is nothing in dcache for this name yet and d_lookup()
+         * returns NULL.  We proceed to real_lookup(), and while we do this,
+         * another process does open on the same file we looking up (most simple
+         * reproducer), open succeeds and the dentry is added. Now back to
+         * us. In real_lookup() we do d_lookup() again and suddenly find the
+         * dentry, so we call d_revalidate on it, but there is no lock, so
+         * without this code we would return 0, but unpatched real_lookup just
+         * returns -ENOENT in such a case instead of retrying the lookup. Once
+         * this is dealt with in real_lookup(), all of this ugly mess can go and
+         * we can just check locks in ->d_revalidate without doing any RPCs
+         * ever.
+         */
+do_lookup:
+        if (it != &lookup_it) {
+                /* MDS_INODELOCK_UPDATE needed for IT_GETATTR case. */
+                if (it->it_op == IT_GETATTR)
+                        lookup_it.it_op = IT_GETATTR;
+                ll_lookup_finish_locks(it, de);
+                it = &lookup_it;
+        }
+
+        /* Do real lookup here. */
+        op_data = ll_prep_md_op_data(NULL, parent, NULL, de->d_name.name,
+                                     de->d_name.len, 0, (it->it_op & IT_CREAT ?
+                                                         LUSTRE_OPC_CREATE :
+                                                         LUSTRE_OPC_ANY), NULL);
+        if (IS_ERR(op_data))
+                RETURN(PTR_ERR(op_data));
+
+        rc = md_intent_lock(exp, op_data, NULL, 0,  it, 0, &req,
+                            ll_md_blocking_ast, 0);
+        if (rc >= 0) {
+                struct mdt_body *mdt_body;
+                struct lu_fid fid = {.f_seq = 0, .f_oid = 0, .f_ver = 0};
+                mdt_body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
+
+                if (de->d_inode)
+                        fid = *ll_inode2fid(de->d_inode);
+
+                /* see if we got same inode, if not - return error */
+                if (lu_fid_eq(&fid, &mdt_body->fid1)) {
+                        ll_finish_md_op_data(op_data);
+                        op_data = NULL;
+                        goto revalidate_finish;
+                }
+                ll_intent_release(it);
+        }
+        ll_finish_md_op_data(op_data);
+        GOTO(out, rc = 0);
+
+out_sa:
+        /*
+         * For rc == 1 case, should not return directly to prevent losing
+         * statahead windows; for rc == 0 case, the "lookup" will be done later.
+         */
+        if (it && it->it_op == IT_GETATTR && rc == 1) {
+                first = ll_statahead_enter(de->d_parent->d_inode, &de, 0);
+                if (!first)
+                        ll_statahead_exit(de, 1);
+                else if (first == -EEXIST)
+                        ll_statahead_mark(de);
         }
 
-        CDEBUG(D_DENTRY, "revalidated dentry %*s (%p) parent %p "
-               "inode %p refc %d\n", de->d_name.len,
-               de->d_name.name, de, de->d_parent, de->d_inode,
-               atomic_read(&de->d_count));
-        ll_lookup_finish_locks(it, de);
-        de->d_flags &= ~DCACHE_LUSTRE_INVALID;
-        if (!((de->d_inode->i_mode & S_ISUID) &&S_ISDIR(de->d_inode->i_mode)) ||
-            !(flags & LOOKUP_CONTINUE || (it->it_op & (IT_CHDIR | IT_OPEN))))
-                return rc;
-
-        if (nd)
-                (void)ll_dir_process_mount_object(de, nd->mnt);
         return rc;
 }
 
@@ -342,6 +638,7 @@ int ll_revalidate_it(struct dentry *de, int flags, struct nameidata *nd,
         struct ll_sb_info *sbi = ll_i2sbi(inode);
         struct ll_dentry_data *ldd = ll_d2d(de);
         struct obd_client_handle *handle;
+        struct obd_capa *oc;
         int rc = 0;
         ENTRY;
         LASSERT(ldd);
@@ -365,9 +662,9 @@ int ll_revalidate_it(struct dentry *de, int flags, struct nameidata *nd,
         unlock_kernel();
 
         handle = (flag) ? &ldd->lld_mnt_och : &ldd->lld_cwd_och;
-        rc = obd_pin(sbi->ll_mdc_exp, inode->i_ino, inode->i_generation,
-                     inode->i_mode & S_IFMT, handle, flag);
-
+        oc = ll_mdscapa_get(inode);
+        rc = obd_pin(sbi->ll_md_exp, ll_inode2fid(inode), oc, handle, flag);
+        capa_put(oc);
         if (rc) {
                 lock_kernel();
                 memset(handle, 0, sizeof(*handle));
@@ -415,54 +712,106 @@ int ll_revalidate_it(struct dentry *de, int flags, struct nameidata *nd,
                 return;
         }
 
-        rc = obd_unpin(sbi->ll_mdc_exp, &handle, flag);
+        rc = obd_unpin(sbi->ll_md_exp, &handle, flag);
         EXIT;
         return;
 }
 
-#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
+#ifdef HAVE_VFS_INTENT_PATCHES
 static int ll_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
 {
         int rc;
         ENTRY;
 
         if (nd && nd->flags & LOOKUP_LAST && !(nd->flags & LOOKUP_LINK_NOTLAST))
-                rc = ll_revalidate_it(dentry, nd->flags, nd, &nd->intent);
+                rc = ll_revalidate_it(dentry, nd->flags, &nd->intent);
         else
-                rc = ll_revalidate_it(dentry, 0, nd, NULL);
+                rc = ll_revalidate_it(dentry, 0, NULL);
 
         RETURN(rc);
 }
+#else
+int ll_revalidate_nd(struct dentry *dentry, struct nameidata *nd)
+{
+        int rc;
+        ENTRY;
+
+        if (nd && !(nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT))) {
+                struct lookup_intent *it;
+                it = ll_convert_intent(&nd->intent.open, nd->flags);
+                if (IS_ERR(it))
+                        RETURN(0);
+                if (it->it_op == (IT_OPEN|IT_CREAT))
+                        if (nd->intent.open.flags & O_EXCL) {
+                                CDEBUG(D_VFSTRACE, "create O_EXCL, returning 0\n");
+                                rc = 0;
+                                goto out_it;
+                        }
+
+                rc = ll_revalidate_it(dentry, nd->flags, it);
+
+                if (rc && (nd->flags & LOOKUP_OPEN) &&
+                    it_disposition(it, DISP_OPEN_OPEN)) {/*Open*/
+#ifdef HAVE_FILE_IN_STRUCT_INTENT
+// XXX Code duplication with ll_lookup_nd
+                        if (S_ISFIFO(dentry->d_inode->i_mode)) {
+                                // We cannot call open here as it would
+                                // deadlock.
+                                ptlrpc_req_finished(
+                                               (struct ptlrpc_request *)
+                                                  it->d.lustre.it_data);
+                        } else {
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17))
+/* 2.6.1[456] have a bug in open_namei() that forgets to check
+ * nd->intent.open.file for error, so we need to return it as lookup's result
+ * instead */
+                                struct file *filp;
+
+                                nd->intent.open.file->private_data = it;
+                                filp = lookup_instantiate_filp(nd, dentry,NULL);
+                                if (IS_ERR(filp)) {
+                                        rc = PTR_ERR(filp);
+                                }
+#else
+                                nd->intent.open.file->private_data = it;
+                                (void)lookup_instantiate_filp(nd, dentry,NULL);
 #endif
+                        }
+#else
+                        ll_release_openhandle(dentry, it);
+#endif /* HAVE_FILE_IN_STRUCT_INTENT */
+                }
+                if (!rc && (nd->flags & LOOKUP_CREATE) &&
+                    it_disposition(it, DISP_OPEN_CREATE)) {
+                        /* We created something but we may only return
+                         * negative dentry here, so save request in dentry,
+                         * if lookup will be called later on, it will
+                         * pick the request, otherwise it would be freed
+                         * with dentry */
+                        ll_d2d(dentry)->lld_it = it;
+                        it = NULL; /* avoid freeing */
+                }
 
-#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
-static void ll_dentry_iput(struct dentry *dentry, struct inode *inode)
-{
-        struct ll_sb_info *sbi = ll_i2sbi(inode);
-        struct ll_fid parent, child;
-
-        LASSERT(dentry->d_parent && dentry->d_parent->d_inode);
-        ll_inode2fid(&parent, dentry->d_parent->d_inode);
-        ll_inode2fid(&child, inode);
-        md_change_cbdata_name(sbi->ll_mdc_exp, &parent,
-                              (char *)dentry->d_name.name, 
-                              dentry->d_name.len, &child, 
-                              null_if_equal, inode);
-        iput(inode);
+out_it:
+                if (it) {
+                        ll_intent_release(it);
+                        OBD_FREE(it, sizeof(*it));
+                }
+        } else {
+                rc = ll_revalidate_it(dentry, 0, NULL);
+        }
+
+        RETURN(rc);
 }
-#else
-#error "implement ->d_iput() for 2.6"
 #endif
 
 struct dentry_operations ll_d_ops = {
-#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
         .d_revalidate = ll_revalidate_nd,
-#else
-        .d_revalidate_it = ll_revalidate_it,
-#endif
         .d_release = ll_release,
-        .d_iput = ll_dentry_iput,
         .d_delete = ll_ddelete,
+#ifdef DCACHE_LUSTRE_INVALID
+        .d_compare = ll_dcompare,
+#endif
 #if 0
         .d_pin = ll_pin,
         .d_unpin = ll_unpin,