/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * 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.
 *
 * 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
 * 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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#define DEBUG_SUBSYSTEM S_LMV
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <asm/div64.h>
#include <linux/seq_file.h>
#include <linux/namei.h>
#include "../include/lustre_intent.h"
#include "../include/obd_support.h"
#include "../include/lustre/lustre_idl.h"
#include "../include/lustre_lib.h"
#include "../include/lustre_net.h"
#include "../include/lustre_dlm.h"
#include "../include/obd_class.h"
#include "../include/lprocfs_status.h"
#include "lmv_internal.h"

static int lmv_intent_remote(struct obd_export *exp, void *lmm,
                             int lmmsize, struct lookup_intent *it,
                             const struct lu_fid *parent_fid, int flags,
                             struct ptlrpc_request **reqp,
                             ldlm_blocking_callback cb_blocking,
                             __u64 extra_lock_flags)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd          *lmv = &obd->u.lmv;
        struct ptlrpc_request   *req = NULL;
        struct lustre_handle    plock;
        struct md_op_data       *op_data;
        struct lmv_tgt_desc     *tgt;
        struct mdt_body         *body;
        int                     pmode;
        int                     rc = 0;

        body = req_capsule_server_get(&(*reqp)->rq_pill, &RMF_MDT_BODY);
        if (body == NULL)
                return -EPROTO;

        LASSERT((body->valid & OBD_MD_MDS));

        /*
         * Unfortunately, we have to lie to MDC/MDS to retrieve
         * attributes llite needs and provideproper locking.
         */
        if (it->it_op & IT_LOOKUP)
                it->it_op = IT_GETATTR;

        /*
         * We got LOOKUP lock, but we really need attrs.
         */
        pmode = it->d.lustre.it_lock_mode;
        if (pmode) {
                plock.cookie = it->d.lustre.it_lock_handle;
                it->d.lustre.it_lock_mode = 0;
                it->d.lustre.it_data = NULL;
        }

        LASSERT(fid_is_sane(&body->fid1));

        tgt = lmv_find_target(lmv, &body->fid1);
        if (IS_ERR(tgt)) {
                rc = PTR_ERR(tgt);
                goto out;
        }

        OBD_ALLOC_PTR(op_data);
        if (op_data == NULL) {
                rc = -ENOMEM;
                goto out;
        }

        op_data->op_fid1 = body->fid1;
        /* Sent the parent FID to the remote MDT */
        if (parent_fid != NULL) {
                /* The parent fid is only for remote open to
                 * check whether the open is from OBF,
                 * see mdt_cross_open */
                LASSERT(it->it_op & IT_OPEN);
                op_data->op_fid2 = *parent_fid;
                /* Add object FID to op_fid3, in case it needs to check stale
                 * (M_CHECK_STALE), see mdc_finish_intent_lock */
                op_data->op_fid3 = body->fid1;
        }

        op_data->op_bias = MDS_CROSS_REF;
        CDEBUG(D_INODE, "REMOTE_INTENT with fid="DFID" -> mds #%d\n",
               PFID(&body->fid1), tgt->ltd_idx);

        rc = md_intent_lock(tgt->ltd_exp, op_data, lmm, lmmsize, it,
                            flags, &req, cb_blocking, extra_lock_flags);
        if (rc)
                goto out_free_op_data;

        /*
         * LLite needs LOOKUP lock to track dentry revocation in order to
         * maintain dcache consistency. Thus drop UPDATE|PERM lock here
         * and put LOOKUP in request.
         */
        if (it->d.lustre.it_lock_mode != 0) {
                it->d.lustre.it_remote_lock_handle =
                                        it->d.lustre.it_lock_handle;
                it->d.lustre.it_remote_lock_mode = it->d.lustre.it_lock_mode;
        }

        it->d.lustre.it_lock_handle = plock.cookie;
        it->d.lustre.it_lock_mode = pmode;

out_free_op_data:
        OBD_FREE_PTR(op_data);
out:
        if (rc && pmode)
                ldlm_lock_decref(&plock, pmode);

        ptlrpc_req_finished(*reqp);
        *reqp = req;
        return rc;
}

/*
 * IT_OPEN is intended to open (and create, possible) an object. Parent (pid)
 * may be split dir.
 */
int lmv_intent_open(struct obd_export *exp, struct md_op_data *op_data,
                    void *lmm, int lmmsize, struct lookup_intent *it,
                    int flags, struct ptlrpc_request **reqp,
                    ldlm_blocking_callback cb_blocking,
                    __u64 extra_lock_flags)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd          *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        struct mdt_body         *body;
        int                     rc;

        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        /* If it is ready to open the file by FID, do not need
         * allocate FID at all, otherwise it will confuse MDT */
        if ((it->it_op & IT_CREAT) &&
            !(it->it_flags & MDS_OPEN_BY_FID)) {
                /*
                 * For open with IT_CREATE and for IT_CREATE cases allocate new
                 * fid and setup FLD for it.
                 */
                op_data->op_fid3 = op_data->op_fid2;
                rc = lmv_fid_alloc(exp, &op_data->op_fid2, op_data);
                if (rc != 0)
                        return rc;
        }

        CDEBUG(D_INODE, "OPEN_INTENT with fid1=" DFID ", fid2=" DFID ", name='%s' -> mds #%d\n",
               PFID(&op_data->op_fid1),
               PFID(&op_data->op_fid2), op_data->op_name, tgt->ltd_idx);

        rc = md_intent_lock(tgt->ltd_exp, op_data, lmm, lmmsize, it, flags,
                            reqp, cb_blocking, extra_lock_flags);
        if (rc != 0)
                return rc;
        /*
         * Nothing is found, do not access body->fid1 as it is zero and thus
         * pointless.
         */
        if ((it->d.lustre.it_disposition & DISP_LOOKUP_NEG) &&
            !(it->d.lustre.it_disposition & DISP_OPEN_CREATE) &&
            !(it->d.lustre.it_disposition & DISP_OPEN_OPEN))
                return rc;

        body = req_capsule_server_get(&(*reqp)->rq_pill, &RMF_MDT_BODY);
        if (body == NULL)
                return -EPROTO;
        /*
         * Not cross-ref case, just get out of here.
         */
        if (likely(!(body->valid & OBD_MD_MDS)))
                return 0;

        /*
         * Okay, MDS has returned success. Probably name has been resolved in
         * remote inode.
         */
        rc = lmv_intent_remote(exp, lmm, lmmsize, it, &op_data->op_fid1, flags,
                               reqp, cb_blocking, extra_lock_flags);
        if (rc != 0) {
                LASSERT(rc < 0);
                /*
                 * This is possible, that some userspace application will try to
                 * open file as directory and we will have -ENOTDIR here. As
                 * this is normal situation, we should not print error here,
                 * only debug info.
                 */
                CDEBUG(D_INODE, "Can't handle remote %s: dir " DFID "(" DFID "):%*s: %d\n",
                       LL_IT2STR(it), PFID(&op_data->op_fid2),
                       PFID(&op_data->op_fid1), op_data->op_namelen,
                       op_data->op_name, rc);
                return rc;
        }

        return rc;
}

/*
 * Handler for: getattr, lookup and revalidate cases.
 */
int lmv_intent_lookup(struct obd_export *exp, struct md_op_data *op_data,
                      void *lmm, int lmmsize, struct lookup_intent *it,
                      int flags, struct ptlrpc_request **reqp,
                      ldlm_blocking_callback cb_blocking,
                      __u64 extra_lock_flags)
{
        struct obd_device      *obd = exp->exp_obd;
        struct lmv_obd   *lmv = &obd->u.lmv;
        struct lmv_tgt_desc    *tgt = NULL;
        struct mdt_body *body;
        int                  rc = 0;

        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        if (!fid_is_sane(&op_data->op_fid2))
                fid_zero(&op_data->op_fid2);

        CDEBUG(D_INODE, "LOOKUP_INTENT with fid1="DFID", fid2="DFID
               ", name='%s' -> mds #%d\n", PFID(&op_data->op_fid1),
               PFID(&op_data->op_fid2),
               op_data->op_name ? op_data->op_name : "<NULL>",
               tgt->ltd_idx);

        op_data->op_bias &= ~MDS_CROSS_REF;

        rc = md_intent_lock(tgt->ltd_exp, op_data, lmm, lmmsize, it,
                             flags, reqp, cb_blocking, extra_lock_flags);

        if (rc < 0 || *reqp == NULL)
                return rc;

        /*
         * MDS has returned success. Probably name has been resolved in
         * remote inode. Let's check this.
         */
        body = req_capsule_server_get(&(*reqp)->rq_pill, &RMF_MDT_BODY);
        if (body == NULL)
                return -EPROTO;
        /* Not cross-ref case, just get out of here. */
        if (likely(!(body->valid & OBD_MD_MDS)))
                return 0;

        rc = lmv_intent_remote(exp, lmm, lmmsize, it, NULL, flags, reqp,
                               cb_blocking, extra_lock_flags);

        return rc;
}

int lmv_intent_lock(struct obd_export *exp, struct md_op_data *op_data,
                    void *lmm, int lmmsize, struct lookup_intent *it,
                    int flags, struct ptlrpc_request **reqp,
                    ldlm_blocking_callback cb_blocking,
                    __u64 extra_lock_flags)
{
        struct obd_device *obd = exp->exp_obd;
        int             rc;

        LASSERT(it != NULL);
        LASSERT(fid_is_sane(&op_data->op_fid1));

        CDEBUG(D_INODE, "INTENT LOCK '%s' for '%*s' on "DFID"\n",
               LL_IT2STR(it), op_data->op_namelen, op_data->op_name,
               PFID(&op_data->op_fid1));

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        if (it->it_op & (IT_LOOKUP | IT_GETATTR | IT_LAYOUT))
                rc = lmv_intent_lookup(exp, op_data, lmm, lmmsize, it,
                                       flags, reqp, cb_blocking,
                                       extra_lock_flags);
        else if (it->it_op & IT_OPEN)
                rc = lmv_intent_open(exp, op_data, lmm, lmmsize, it,
                                     flags, reqp, cb_blocking,
                                     extra_lock_flags);
        else
                LBUG();
        return rc;
}