/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 * 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  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.
 *
 * lustre/liblustre/rw.c
 *
 * Lustre Light block IO
 */

#define DEBUG_SUBSYSTEM S_LLITE

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/queue.h>
#include <fcntl.h>
#include <sys/uio.h>

#include <sysio.h>
#ifdef HAVE_XTIO_H
#include <xtio.h>
#endif
#include <fs.h>
#include <mount.h>
#include <inode.h>
#ifdef HAVE_FILE_H
#include <file.h>
#endif

#undef LIST_HEAD

#include "llite_lib.h"

typedef ssize_t llu_file_piov_t(const struct iovec *iovec, int iovlen,
                                _SYSIO_OFF_T pos, ssize_t len,
                                void *private);

size_t llap_cookie_size;

static int llu_lock_to_stripe_offset(struct inode *inode, struct ldlm_lock *lock)
{
        struct llu_inode_info *lli = llu_i2info(inode);
        struct lov_stripe_md *lsm = lli->lli_smd;
        struct obd_export *exp = llu_i2obdexp(inode);
        struct {
                char name[16];
                struct ldlm_lock *lock;
        } key = { .name = KEY_LOCK_TO_STRIPE, .lock = lock };
        __u32 stripe, vallen = sizeof(stripe);
        int rc;
        ENTRY;

        if (lsm->lsm_stripe_count == 1)
                RETURN(0);

        /* get our offset in the lov */
        rc = obd_get_info(exp, sizeof(key), &key, &vallen, &stripe, lsm);
        if (rc != 0) {
                CERROR("obd_get_info: rc = %d\n", rc);
                LBUG();
        }
        LASSERT(stripe < lsm->lsm_stripe_count);
        RETURN(stripe);
}

int llu_extent_lock_cancel_cb(struct ldlm_lock *lock,
                              struct ldlm_lock_desc *new, void *data,
                              int flag)
{
        struct lustre_handle lockh = { 0 };
        int rc;
        ENTRY;

        if ((unsigned long)data > 0 && (unsigned long)data < 0x1000) {
                LDLM_ERROR(lock, "cancelling lock with bad data %p", data);
                LBUG();
        }

        switch (flag) {
        case LDLM_CB_BLOCKING:
                ldlm_lock2handle(lock, &lockh);
                rc = ldlm_cli_cancel(&lockh);
                if (rc != ELDLM_OK)
                        CERROR("ldlm_cli_cancel failed: %d\n", rc);
                break;
        case LDLM_CB_CANCELING: {
                struct inode *inode;
                struct llu_inode_info *lli;
                struct lov_stripe_md *lsm;
                __u32 stripe;
                __u64 kms;

                /* This lock wasn't granted, don't try to evict pages */
                if (lock->l_req_mode != lock->l_granted_mode)
                        RETURN(0);

                inode = llu_inode_from_lock(lock);
                if (!inode)
                        RETURN(0);
                lli= llu_i2info(inode);
                if (!lli)
                        goto iput;
                if (!lli->lli_smd)
                        goto iput;
                lsm = lli->lli_smd;

                stripe = llu_lock_to_stripe_offset(inode, lock);
                lock_res_and_lock(lock);
                kms = ldlm_extent_shift_kms(lock,
                                            lsm->lsm_oinfo[stripe]->loi_kms);
                unlock_res_and_lock(lock);
                if (lsm->lsm_oinfo[stripe]->loi_kms != kms)
                        LDLM_DEBUG(lock, "updating kms from "LPU64" to "LPU64,
                                   lsm->lsm_oinfo[stripe]->loi_kms, kms);
                loi_kms_set(lsm->lsm_oinfo[stripe], kms);
iput:
                I_RELE(inode);
                break;
        }
        default:
                LBUG();
        }

        RETURN(0);
}

static int llu_glimpse_callback(struct ldlm_lock *lock, void *reqp)
{
        struct ptlrpc_request *req = reqp;
        struct inode *inode = llu_inode_from_lock(lock);
        struct llu_inode_info *lli;
        struct ost_lvb *lvb;
        int rc, stripe = 0;
        ENTRY;

        if (inode == NULL)
                GOTO(out, rc = -ELDLM_NO_LOCK_DATA);
        lli = llu_i2info(inode);
        if (lli == NULL)
                GOTO(iput, rc = -ELDLM_NO_LOCK_DATA);
        if (lli->lli_smd == NULL)
                GOTO(iput, rc = -ELDLM_NO_LOCK_DATA);

        /* First, find out which stripe index this lock corresponds to. */
        if (lli->lli_smd->lsm_stripe_count > 1)
                stripe = llu_lock_to_stripe_offset(inode, lock);

        req_capsule_extend(&req->rq_pill, &RQF_LDLM_GL_CALLBACK);
        req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
                             sizeof(*lvb));
        rc = req_capsule_server_pack(&req->rq_pill);
        if (rc) {
                CERROR("failed pack reply: %d\n", rc);
                GOTO(iput, rc);
        }

        lvb = req_capsule_server_get(&req->rq_pill, &RMF_DLM_LVB);
        lvb->lvb_size = lli->lli_smd->lsm_oinfo[stripe]->loi_kms;

        LDLM_DEBUG(lock, "i_size: %llu -> stripe number %u -> kms "LPU64,
                   (__u64)llu_i2stat(inode)->st_size, stripe,lvb->lvb_size);
 iput:
        I_RELE(inode);
 out:
        /* These errors are normal races, so we don't want to fill the console
         * with messages by calling ptlrpc_error() */
        if (rc == -ELDLM_NO_LOCK_DATA)
                lustre_pack_reply(req, 1, NULL, NULL);

        req->rq_status = rc;
        return rc;
}

int llu_merge_lvb(struct inode *inode)
{
        struct llu_inode_info *lli = llu_i2info(inode);
        struct llu_sb_info *sbi = llu_i2sbi(inode);
        struct intnl_stat *st = llu_i2stat(inode);
        struct ost_lvb lvb;
        int rc;
        ENTRY;

        inode_init_lvb(inode, &lvb);
        rc = obd_merge_lvb(sbi->ll_dt_exp, lli->lli_smd, &lvb, 0);
        st->st_size = lvb.lvb_size;
        st->st_blocks = lvb.lvb_blocks;
        /* handle st_blocks overflow gracefully */
        if (st->st_blocks < lvb.lvb_blocks)
                st->st_blocks = ~0UL;
        st->st_mtime = lvb.lvb_mtime;
        st->st_atime = lvb.lvb_atime;
        st->st_ctime = lvb.lvb_ctime;

        RETURN(rc);
}

int llu_extent_lock(struct ll_file_data *fd, struct inode *inode,
                    struct lov_stripe_md *lsm, int mode,
                    ldlm_policy_data_t *policy, struct lustre_handle *lockh,
                    int ast_flags)
{
        struct llu_sb_info *sbi = llu_i2sbi(inode);
        struct intnl_stat *st = llu_i2stat(inode);
        struct ldlm_enqueue_info einfo = { 0 };
        struct obd_info oinfo = { { { 0 } } };
        struct ost_lvb lvb;
        int rc;
        ENTRY;

        LASSERT(!lustre_handle_is_used(lockh));
        CLASSERT(ELDLM_OK == 0);

        /* XXX phil: can we do this?  won't it screw the file size up? */
        if ((fd && (fd->fd_flags & LL_FILE_IGNORE_LOCK)) ||
            (sbi->ll_flags & LL_SBI_NOLCK) || mode == LCK_NL)
                RETURN(0);

        CDEBUG(D_DLMTRACE, "Locking inode %llu, start "LPU64" end "LPU64"\n",
               (__u64)st->st_ino, policy->l_extent.start,
               policy->l_extent.end);

        einfo.ei_type = LDLM_EXTENT;
        einfo.ei_mode = mode;
        einfo.ei_cb_bl = llu_extent_lock_cancel_cb;
        einfo.ei_cb_cp = ldlm_completion_ast;
        einfo.ei_cb_gl = llu_glimpse_callback;
        einfo.ei_cbdata = inode;

        oinfo.oi_policy = *policy;
        oinfo.oi_lockh = lockh;
        oinfo.oi_md = lsm;
        oinfo.oi_flags = ast_flags;

        rc = obd_enqueue(sbi->ll_dt_exp, &oinfo, &einfo, NULL);
        *policy = oinfo.oi_policy;
        if (rc > 0)
                rc = -EIO;

        inode_init_lvb(inode, &lvb);
        obd_merge_lvb(sbi->ll_dt_exp, lsm, &lvb, 1);
        if (policy->l_extent.start == 0 &&
            policy->l_extent.end == OBD_OBJECT_EOF)
                st->st_size = lvb.lvb_size;

        if (rc == 0) {
                st->st_mtime = lvb.lvb_mtime;
                st->st_atime = lvb.lvb_atime;
                st->st_ctime = lvb.lvb_ctime;
        }

        RETURN(rc);
}

int llu_extent_unlock(struct ll_file_data *fd, struct inode *inode,
                struct lov_stripe_md *lsm, int mode,
                struct lustre_handle *lockh)
{
        struct llu_sb_info *sbi = llu_i2sbi(inode);
        int rc;
        ENTRY;

        CLASSERT(ELDLM_OK == 0);

        /* XXX phil: can we do this?  won't it screw the file size up? */
        if ((fd && (fd->fd_flags & LL_FILE_IGNORE_LOCK)) ||
            (sbi->ll_flags & LL_SBI_NOLCK) || mode == LCK_NL)
                RETURN(0);

        rc = obd_cancel(sbi->ll_dt_exp, lsm, mode, lockh);

        RETURN(rc);
}

static
ssize_t llu_file_prwv(const struct iovec *iovec, int iovlen,
                        _SYSIO_OFF_T pos, ssize_t len,
                        void *private)
{
        struct llu_io_session *session = (struct llu_io_session *) private;
        struct inode *inode = session->lis_inode;
        struct llu_inode_info *lli = llu_i2info(inode);
        int err;
        struct lu_env *env;
        struct cl_io  *io;
        struct slp_io *sio;
        int refcheck;
        ENTRY;

        /* in a large iov read/write we'll be repeatedly called.
         * so give a chance to answer cancel ast here
         */
        liblustre_wait_event(0);

        if (len == 0 || iovlen == 0)
                RETURN(0);

        if (pos + len > lli->lli_maxbytes)
                RETURN(-ERANGE);

        env = cl_env_get(&refcheck);
        if (IS_ERR(env))
                RETURN(PTR_ERR(env));

        io = &ccc_env_info(env)->cti_io;

        if (cl_io_rw_init(env, io, session->lis_cmd == OBD_BRW_WRITE?CIT_WRITE:
                                                                      CIT_READ,
                          pos, len) == 0) {
                struct ccc_io *cio;
                sio = slp_env_io(env);
                cio = ccc_env_io(env);
                /* XXX this is not right: cio->cui_iov can be modified. */
                cio->cui_iov = (struct iovec *)iovec;
                cio->cui_nrsegs = iovlen;
                sio->sio_session = session;
                err = cl_io_loop(env, io);
        } else {
                /* XXX WTF? */
                LBUG();
        }
        cl_io_fini(env, io);
        cl_env_put(env, &refcheck);

        if (err < 0)
                RETURN(err);

        RETURN(len);
}

static
struct llu_io_session *get_io_session(struct inode *ino, int ngroups, int cmd)
{
        struct llu_io_session *session;

        OBD_ALLOC_PTR(session);
        if (!session)
                return NULL;

        I_REF(ino);
        session->lis_inode = ino;
        session->lis_max_groups = ngroups;
        session->lis_cmd = cmd;
        return session;
}

static void put_io_session(struct llu_io_session *session)
{
        I_RELE(session->lis_inode);
        OBD_FREE_PTR(session);
}

static int llu_file_rwx(struct inode *ino,
                        struct ioctx *ioctx,
                        int read)
{
        struct llu_io_session *session;
        ssize_t cc;
        int cmd = read ? OBD_BRW_READ : OBD_BRW_WRITE;
        ENTRY;

        LASSERT(ioctx->ioctx_xtvlen >= 0);
        LASSERT(ioctx->ioctx_iovlen >= 0);

        liblustre_wait_event(0);

        if (!ioctx->ioctx_xtvlen)
                RETURN(0);

        /* XXX consider other types later */
        if (S_ISDIR(llu_i2stat(ino)->st_mode))
                RETURN(-EISDIR);
        if (!S_ISREG(llu_i2stat(ino)->st_mode))
                RETURN(-EOPNOTSUPP);

        session = get_io_session(ino, ioctx->ioctx_xtvlen * 2, cmd);
        if (!session)
                RETURN(-ENOMEM);

        cc = _sysio_enumerate_extents(ioctx->ioctx_xtv, ioctx->ioctx_xtvlen,
                                      ioctx->ioctx_iov, ioctx->ioctx_iovlen,
                                      llu_file_prwv, session);

        if (cc >= 0) {
                LASSERT(!ioctx->ioctx_cc);
                ioctx->ioctx_private = session;
                cc = 0;
        } else {
                put_io_session(session);
        }

        liblustre_wait_event(0);
        RETURN(cc);
}

void llu_io_init(struct cl_io *io, struct inode *inode, int write)
{
        struct llu_inode_info *lli = llu_i2info(inode);

        memset(io, 0, sizeof *io);

        io->u.ci_rw.crw_nonblock = lli->lli_open_flags & O_NONBLOCK;
        if (write)
                io->u.ci_wr.wr_append = lli->lli_open_flags & O_APPEND;
        io->ci_obj  = llu_i2info(inode)->lli_clob;

        if ((lli->lli_open_flags & O_APPEND) && write)
                io->ci_lockreq = CILR_MANDATORY;
        else
                io->ci_lockreq = CILR_NEVER;
}

int llu_iop_read(struct inode *ino,
                 struct ioctx *ioctx)
{
        struct intnl_stat *st = llu_i2stat(ino);
        struct lu_env *env;
        struct cl_io  *io;
        int refcheck;
        int ret;

        /* BUG: 5972 */
        st->st_atime = CURRENT_TIME;

        env = cl_env_get(&refcheck);
        if (IS_ERR(env))
                RETURN(PTR_ERR(env));

        io = &ccc_env_info(env)->cti_io;
        llu_io_init(io, ino, 0);

        ret = llu_file_rwx(ino, ioctx, 1);

        cl_env_put(env, &refcheck);
        return ret;
}

int llu_iop_write(struct inode *ino,
                  struct ioctx *ioctx)
{
        struct intnl_stat *st = llu_i2stat(ino);
        struct lu_env *env;
        struct cl_io  *io;
        int refcheck;
        int ret;

        st->st_mtime = st->st_ctime = CURRENT_TIME;

        env = cl_env_get(&refcheck);
        if (IS_ERR(env))
                RETURN(PTR_ERR(env));

        io = &ccc_env_info(env)->cti_io;
        llu_io_init(io, ino, 1);

        ret = llu_file_rwx(ino, ioctx, 0);
        cl_env_put(env, &refcheck);
        return ret;
}

int llu_iop_iodone(struct ioctx *ioctx)
{
        struct llu_io_session *session;
        struct lu_env *env;
        struct cl_io  *io;
        int refcheck;
        ENTRY;

        liblustre_wait_event(0);

        env = cl_env_get(&refcheck);
        if (IS_ERR(env))
                RETURN(PTR_ERR(env));

        io = &ccc_env_info(env)->cti_io;
        cl_io_fini(env, io);
        cl_env_put(env, &refcheck);
        session = (struct llu_io_session *) ioctx->ioctx_private;
        LASSERT(session);
        LASSERT(!IS_ERR(session));

        if (session->lis_rc == 0) {
                ioctx->ioctx_cc = session->lis_rwcount;
        } else {
                LASSERT(session->lis_rc < 0);
                ioctx->ioctx_cc = -1;
                ioctx->ioctx_errno = -session->lis_rc;
        }

        put_io_session(session);
        ioctx->ioctx_private = NULL;
        liblustre_wait_event(0);

        RETURN(1);
}