/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/fs.h>
#include <linux/dlm.h>
#include <linux/types.h>
#include <linux/gfs2_ondisk.h>

#include "incore.h"
#include "glock.h"
#include "util.h"


static void gdlm_ast(void *arg)
{
        struct gfs2_glock *gl = arg;
        unsigned ret = gl->gl_state;

        BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);

        if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
                memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);

        switch (gl->gl_lksb.sb_status) {
        case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
                kmem_cache_free(gfs2_glock_cachep, gl);
                return;
        case -DLM_ECANCEL: /* Cancel while getting lock */
                ret |= LM_OUT_CANCELED;
                goto out;
        case -EAGAIN: /* Try lock fails */
                goto out;
        case -EINVAL: /* Invalid */
        case -ENOMEM: /* Out of memory */
                ret |= LM_OUT_ERROR;
                goto out;
        case 0: /* Success */
                break;
        default: /* Something unexpected */
                BUG();
        }

        ret = gl->gl_req;
        if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
                if (gl->gl_req == LM_ST_SHARED)
                        ret = LM_ST_DEFERRED;
                else if (gl->gl_req == LM_ST_DEFERRED)
                        ret = LM_ST_SHARED;
                else
                        BUG();
        }

        set_bit(GLF_INITIAL, &gl->gl_flags);
        gfs2_glock_complete(gl, ret);
        return;
out:
        if (!test_bit(GLF_INITIAL, &gl->gl_flags))
                gl->gl_lksb.sb_lkid = 0;
        gfs2_glock_complete(gl, ret);
}

static void gdlm_bast(void *arg, int mode)
{
        struct gfs2_glock *gl = arg;

        switch (mode) {
        case DLM_LOCK_EX:
                gfs2_glock_cb(gl, LM_ST_UNLOCKED);
                break;
        case DLM_LOCK_CW:
                gfs2_glock_cb(gl, LM_ST_DEFERRED);
                break;
        case DLM_LOCK_PR:
                gfs2_glock_cb(gl, LM_ST_SHARED);
                break;
        default:
                printk(KERN_ERR "unknown bast mode %d", mode);
                BUG();
        }
}

/* convert gfs lock-state to dlm lock-mode */

static int make_mode(const unsigned int lmstate)
{
        switch (lmstate) {
        case LM_ST_UNLOCKED:
                return DLM_LOCK_NL;
        case LM_ST_EXCLUSIVE:
                return DLM_LOCK_EX;
        case LM_ST_DEFERRED:
                return DLM_LOCK_CW;
        case LM_ST_SHARED:
                return DLM_LOCK_PR;
        }
        printk(KERN_ERR "unknown LM state %d", lmstate);
        BUG();
        return -1;
}

static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
                      const int req)
{
        u32 lkf = 0;

        if (gfs_flags & LM_FLAG_TRY)
                lkf |= DLM_LKF_NOQUEUE;

        if (gfs_flags & LM_FLAG_TRY_1CB) {
                lkf |= DLM_LKF_NOQUEUE;
                lkf |= DLM_LKF_NOQUEUEBAST;
        }

        if (gfs_flags & LM_FLAG_PRIORITY) {
                lkf |= DLM_LKF_NOORDER;
                lkf |= DLM_LKF_HEADQUE;
        }

        if (gfs_flags & LM_FLAG_ANY) {
                if (req == DLM_LOCK_PR)
                        lkf |= DLM_LKF_ALTCW;
                else if (req == DLM_LOCK_CW)
                        lkf |= DLM_LKF_ALTPR;
                else
                        BUG();
        }

        if (lkid != 0) 
                lkf |= DLM_LKF_CONVERT;

        lkf |= DLM_LKF_VALBLK;

        return lkf;
}

static unsigned int gdlm_lock(struct gfs2_glock *gl,
                              unsigned int req_state, unsigned int flags)
{
        struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
        int error;
        int req;
        u32 lkf;

        gl->gl_req = req_state;
        req = make_mode(req_state);
        lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);

        /*
         * Submit the actual lock request.
         */

        error = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
                         GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
        if (error == -EAGAIN)
                return 0;
        if (error)
                return LM_OUT_ERROR;
        return LM_OUT_ASYNC;
}

static void gdlm_put_lock(struct kmem_cache *cachep, void *ptr)
{
        struct gfs2_glock *gl = ptr;
        struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
        int error;

        if (gl->gl_lksb.sb_lkid == 0) {
                kmem_cache_free(cachep, gl);
                return;
        }

        error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
                           NULL, gl);
        if (error) {
                printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
                       gl->gl_name.ln_type,
                       (unsigned long long)gl->gl_name.ln_number, error);
                return;
        }
}

static void gdlm_cancel(struct gfs2_glock *gl)
{
        struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
        dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
}

static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
{
        struct lm_lockstruct *ls = &sdp->sd_lockstruct;
        int error;

        if (fsname == NULL) {
                fs_info(sdp, "no fsname found\n");
                return -EINVAL;
        }

        error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
                                  DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
                                  (ls->ls_nodir ? DLM_LSFL_NODIR : 0),
                                  GDLM_LVB_SIZE);
        if (error)
                printk(KERN_ERR "dlm_new_lockspace error %d", error);

        return error;
}

static void gdlm_unmount(struct gfs2_sbd *sdp)
{
        struct lm_lockstruct *ls = &sdp->sd_lockstruct;

        if (ls->ls_dlm) {
                dlm_release_lockspace(ls->ls_dlm, 2);
                ls->ls_dlm = NULL;
        }
}

static const match_table_t dlm_tokens = {
        { Opt_jid, "jid=%d"},
        { Opt_id, "id=%d"},
        { Opt_first, "first=%d"},
        { Opt_nodir, "nodir=%d"},
        { Opt_err, NULL },
};

const struct lm_lockops gfs2_dlm_ops = {
        .lm_proto_name = "lock_dlm",
        .lm_mount = gdlm_mount,
        .lm_unmount = gdlm_unmount,
        .lm_put_lock = gdlm_put_lock,
        .lm_lock = gdlm_lock,
        .lm_cancel = gdlm_cancel,
        .lm_tokens = &dlm_tokens,
};