/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
 *
 *   This file is part of Lustre, http://www.lustre.org.
 *
 *   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.
 *
 *   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.
 *
 *   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.
 */

#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/quotaops.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>

/* should NOT be called with the dcache lock, see fs/dcache.c */
void ll_release(struct dentry *de)
{
        ENTRY;
        OBD_FREE(de->d_fsdata, sizeof(struct ll_dentry_data));
        EXIT;
}

void ll_set_dd(struct dentry *de)
{
        ENTRY;
        LASSERT(de != NULL);

        lock_kernel();

        if (de->d_fsdata == NULL) {
                OBD_ALLOC(de->d_fsdata, sizeof(struct ll_dentry_data));
                sema_init(&ll_d2d(de)->lld_it_sem, 1);
        }

        unlock_kernel();

        EXIT;
}

void ll_intent_release(struct dentry *de, struct lookup_intent *it)
{
        struct lustre_handle *handle;
        ENTRY;

        LASSERT(ll_d2d(de) != NULL);

        if (it->it_lock_mode) {
                handle = (struct lustre_handle *)it->it_lock_handle;
                ldlm_lock_decref(handle, it->it_lock_mode);

                /* intent_release may be called multiple times, from
                   this thread and we don't want to double-decref this
                   lock (see bug 494) */
                it->it_lock_mode = 0;
        }

        if (!de->d_it || it->it_op == IT_RELEASED_MAGIC) {
                EXIT;
                return;
        }

        if (de->d_it == it)
                LL_GET_INTENT(de, it);
        else 
                CERROR("STRANGE intent release: %p %p\n", de->d_it, it);

        EXIT;
}

extern struct dentry *ll_find_alias(struct inode *, struct dentry *);

static int revalidate2_finish(int flag, struct ptlrpc_request *request,
                              struct dentry **de, struct lookup_intent *it,
                              int offset, obd_id ino)
{
        struct mds_body *body;
        struct lov_mds_md *lmm = NULL;
        int rc = 0; 
        ENTRY;

        if (!(flag & LL_LOOKUP_NEGATIVE)) {
                body = lustre_msg_buf(request->rq_repmsg, offset);
                if (body->valid & OBD_MD_FLEASIZE)
                        lmm = lustre_msg_buf(request->rq_repmsg, offset + 1);
                ll_update_inode((*de)->d_inode, body, lmm);
                mdc_lock_set_inode((struct lustre_handle *)it->it_lock_handle,
                                   (*de)->d_inode);
        } else 
                rc = -ENOENT;

        ptlrpc_req_finished(request);
        RETURN(rc);
}

int ll_have_md_lock(struct dentry *de)
{
        struct ll_sb_info *sbi = ll_s2sbi(de->d_sb);
        struct lustre_handle lockh;
        struct ldlm_res_id res_id = { .name = {0} };
        struct obd_device *obddev;
        ENTRY;

        if (!de->d_inode)
               RETURN(0);

        obddev = class_conn2obd(&sbi->ll_mdc_conn);
        res_id.name[0] = de->d_inode->i_ino;
        res_id.name[1] = de->d_inode->i_generation;

        CDEBUG(D_INFO, "trying to match res "LPU64"\n", res_id.name[0]);

        if (ldlm_lock_match(obddev->obd_namespace, LDLM_FL_BLOCK_GRANTED,
                            &res_id, LDLM_PLAIN, NULL, 0, LCK_PR, &lockh)) {
                ldlm_lock_decref(&lockh, LCK_PR);
                RETURN(1);
        }

        if (ldlm_lock_match(obddev->obd_namespace, LDLM_FL_BLOCK_GRANTED,
                            &res_id, LDLM_PLAIN, NULL, 0, LCK_PW, &lockh)) {
                ldlm_lock_decref(&lockh, LCK_PW);
                RETURN(1);
        }
        RETURN(0);
}

int ll_revalidate2(struct dentry *de, int flags, struct lookup_intent *it)
{
        int rc;
        ENTRY;

        /* We don't want to cache negative dentries, so return 0 immediately.
         * We believe that this is safe, that negative dentries cannot be
         * pinned by someone else */
        if (de->d_inode == NULL) {
                CDEBUG(D_INODE, "negative dentry: ret 0 to force lookup2\n");
                RETURN(0);
        }

        if (it == NULL || it->it_op == IT_GETATTR) {
                /* We could just return 1 immediately, but since we should only
                 * be called in revalidate2 if we already have a lock, let's
                 * verify that. */
                struct inode *inode = de->d_inode;
                struct ll_sb_info *sbi = ll_i2sbi(inode);
                struct obd_device *obddev = class_conn2obd(&sbi->ll_mdc_conn);
                struct ldlm_res_id res_id =
                        { .name = {inode->i_ino, (__u64)inode->i_generation} };
                struct lustre_handle lockh;
                rc = ldlm_lock_match(obddev->obd_namespace,
                                     LDLM_FL_BLOCK_GRANTED, &res_id,
                                     LDLM_PLAIN, NULL, 0, LCK_PR, &lockh);
                if (rc) {
                        de->d_flags &= ~DCACHE_LUSTRE_INVALID;
                        if (it && it->it_op == IT_GETATTR) {
                                memcpy(it->it_lock_handle, &lockh,
                                       sizeof(lockh));
                                it->it_lock_mode = LCK_PR;
                                LL_SAVE_INTENT(de, it);
                        } else {
                                ldlm_lock_decref(&lockh, LCK_PR);
                        }
                        RETURN(1);
                }
                rc = ldlm_lock_match(obddev->obd_namespace,
                                     LDLM_FL_BLOCK_GRANTED, &res_id,
                                     LDLM_PLAIN, NULL, 0, LCK_PW, &lockh);
                if (rc) {
                        de->d_flags &= ~DCACHE_LUSTRE_INVALID;
                        if (it && it->it_op == IT_GETATTR) {
                                memcpy(it->it_lock_handle, &lockh,
                                       sizeof(lockh));
                                it->it_lock_mode = LCK_PW;
                                LL_SAVE_INTENT(de, it);
                        } else {
                                ldlm_lock_decref(&lockh, LCK_PW);
                        }
                        RETURN(1);
                }
                if (S_ISDIR(de->d_inode->i_mode))
                        ll_invalidate_inode_pages(de->d_inode);
                d_unhash_aliases(de->d_inode);
                RETURN(0);
        }

        rc = ll_intent_lock(de->d_parent->d_inode, &de, it, revalidate2_finish);
        if (rc < 0) {
                CERROR("ll_intent_lock: rc %d : it->it_status %d\n", rc,
                       it->it_status);
                RETURN(0);
        }
        /* unfortunately ll_intent_lock may cause a callback and revoke our
           dentry */
        spin_lock(&dcache_lock);
        list_del_init(&de->d_hash);
        spin_unlock(&dcache_lock);
        d_rehash(de);

        RETURN(1);
}

struct dentry_operations ll_d_ops = {
        .d_revalidate2 = ll_revalidate2,
        .d_intent_release = ll_intent_release,
        .d_release = ll_release,
};