/*
  Copyright (c) 2015 Red Hat, Inc. <http://www.redhat.com>
  This file is part of GlusterFS.

  This file is licensed to you under your choice of the GNU Lesser
  General Public License, version 3 or any later version (LGPLv3 or
  later), or the GNU General Public License, version 2 (GPLv2), in all
  cases as published by the Free Software Foundation.
*/

#include "arbiter.h"
#include "arbiter-mem-types.h"
#include <glusterfs/glusterfs.h>
#include <glusterfs/xlator.h>
#include <glusterfs/logging.h>

static arbiter_inode_ctx_t *
__arbiter_inode_ctx_get(inode_t *inode, xlator_t *this)
{
    arbiter_inode_ctx_t *ctx = NULL;
    int ret = 0;
    uint64_t ctx_addr = 0;

    ret = __inode_ctx_get(inode, this, &ctx_addr);
    if (ret == 0) {
        ctx = (arbiter_inode_ctx_t *)(long)ctx_addr;
        goto out;
    }

    ctx = GF_CALLOC(1, sizeof(*ctx), gf_arbiter_mt_inode_ctx_t);
    if (!ctx)
        goto out;

    ret = __inode_ctx_put(inode, this, (uint64_t)(uintptr_t)ctx);
    if (ret) {
        GF_FREE(ctx);
        ctx = NULL;
        gf_log_callingfn(this->name, GF_LOG_ERROR,
                         "failed to "
                         "set the inode ctx (%s)",
                         uuid_utoa(inode->gfid));
    }
out:
    return ctx;
}

static arbiter_inode_ctx_t *
arbiter_inode_ctx_get(inode_t *inode, xlator_t *this)
{
    arbiter_inode_ctx_t *ctx = NULL;

    LOCK(&inode->lock);
    {
        ctx = __arbiter_inode_ctx_get(inode, this);
    }
    UNLOCK(&inode->lock);
    return ctx;
}

int32_t
arbiter_lookup_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                   int32_t op_ret, int32_t op_errno, inode_t *inode,
                   struct iatt *buf, dict_t *xdata, struct iatt *postparent)
{
    arbiter_inode_ctx_t *ctx = NULL;

    if (op_ret != 0)
        goto unwind;
    ctx = arbiter_inode_ctx_get(inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    memcpy(&ctx->iattbuf, buf, sizeof(ctx->iattbuf));

unwind:
    STACK_UNWIND_STRICT(lookup, frame, op_ret, op_errno, inode, buf, xdata,
                        postparent);
    return 0;
}

int32_t
arbiter_lookup(call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xdata)
{
    STACK_WIND(frame, arbiter_lookup_cbk, FIRST_CHILD(this),
               FIRST_CHILD(this)->fops->lookup, loc, xdata);
    return 0;
}

int32_t
arbiter_truncate(call_frame_t *frame, xlator_t *this, loc_t *loc, off_t offset,
                 dict_t *xdata)
{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    int32_t op_ret = 0;
    int32_t op_errno = 0;

    ctx = arbiter_inode_ctx_get(loc->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
unwind:
    STACK_UNWIND_STRICT(truncate, frame, op_ret, op_errno, buf, buf, NULL);
    return 0;
}

int32_t
arbiter_ftruncate(call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
                  dict_t *xdata)

{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    int32_t op_ret = 0;
    int32_t op_errno = 0;

    ctx = arbiter_inode_ctx_get(fd->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
unwind:
    STACK_UNWIND_STRICT(ftruncate, frame, op_ret, op_errno, buf, buf, NULL);
    return 0;
}

dict_t *
arbiter_fill_writev_xdata(fd_t *fd, dict_t *xdata, xlator_t *this)
{
    dict_t *rsp_xdata = NULL;
    int32_t ret = 0;
    int is_append = 1;

    if (!fd || !fd->inode || gf_uuid_is_null(fd->inode->gfid)) {
        goto out;
    }

    if (!xdata)
        goto out;

    rsp_xdata = dict_new();
    if (!rsp_xdata)
        goto out;

    if (dict_get(xdata, GLUSTERFS_OPEN_FD_COUNT)) {
        ret = dict_set_uint32(rsp_xdata, GLUSTERFS_OPEN_FD_COUNT,
                              fd->inode->fd_count);
        if (ret < 0) {
            gf_msg_debug(this->name, 0,
                         "Failed to set dict value"
                         " for GLUSTERFS_OPEN_FD_COUNT");
        }
    }
    if (dict_get(xdata, GLUSTERFS_WRITE_IS_APPEND)) {
        ret = dict_set_uint32(rsp_xdata, GLUSTERFS_WRITE_IS_APPEND, is_append);
        if (ret < 0) {
            gf_msg_debug(this->name, 0,
                         "Failed to set dict value"
                         " for GLUSTERFS_WRITE_IS_APPEND");
        }
    }
out:
    return rsp_xdata;
}

int32_t
arbiter_writev(call_frame_t *frame, xlator_t *this, fd_t *fd,
               struct iovec *vector, int32_t count, off_t off, uint32_t flags,
               struct iobref *iobref, dict_t *xdata)
{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    dict_t *rsp_xdata = NULL;
    int op_ret = 0;
    int op_errno = 0;

    ctx = arbiter_inode_ctx_get(fd->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
    op_ret = iov_length(vector, count);
    rsp_xdata = arbiter_fill_writev_xdata(fd, xdata, this);
unwind:
    STACK_UNWIND_STRICT(writev, frame, op_ret, op_errno, buf, buf, rsp_xdata);
    if (rsp_xdata)
        dict_unref(rsp_xdata);
    return 0;
}

int32_t
arbiter_fallocate(call_frame_t *frame, xlator_t *this, fd_t *fd,
                  int32_t keep_size, off_t offset, size_t len, dict_t *xdata)
{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    int op_ret = 0;
    int op_errno = 0;

    ctx = arbiter_inode_ctx_get(fd->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
unwind:
    STACK_UNWIND_STRICT(fallocate, frame, op_ret, op_errno, buf, buf, NULL);
    return 0;
}

int32_t
arbiter_discard(call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
                size_t len, dict_t *xdata)
{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    int op_ret = 0;
    int op_errno = 0;

    ctx = arbiter_inode_ctx_get(fd->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
unwind:
    STACK_UNWIND_STRICT(discard, frame, op_ret, op_errno, buf, buf, NULL);
    return 0;
}

int32_t
arbiter_zerofill(call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
                 off_t len, dict_t *xdata)
{
    arbiter_inode_ctx_t *ctx = NULL;
    struct iatt *buf = NULL;
    int op_ret = 0;
    int op_errno = 0;

    ctx = arbiter_inode_ctx_get(fd->inode, this);
    if (!ctx) {
        op_ret = -1;
        op_errno = ENOMEM;
        goto unwind;
    }
    buf = &ctx->iattbuf;
unwind:
    STACK_UNWIND_STRICT(zerofill, frame, op_ret, op_errno, buf, buf, NULL);
    return 0;
}

static int32_t
arbiter_readv(call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
              off_t offset, uint32_t flags, dict_t *xdata)
{
    STACK_UNWIND_STRICT(readv, frame, -1, ENOSYS, NULL, 0, NULL, NULL, NULL);
    return 0;
}

static int32_t
arbiter_seek(call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
             gf_seek_what_t what, dict_t *xdata)
{
    STACK_UNWIND_STRICT(seek, frame, -1, ENOSYS, 0, xdata);
    return 0;
}

int32_t
mem_acct_init(xlator_t *this)
{
    int ret = -1;

    ret = xlator_mem_acct_init(this, gf_arbiter_mt_end + 1);
    if (ret)
        gf_log(this->name, GF_LOG_ERROR,
               "Memory accounting "
               "initialization failed.");
    return ret;
}

int
reconfigure(xlator_t *this, dict_t *options)
{
    return 0;
}

int
arbiter_forget(xlator_t *this, inode_t *inode)
{
    arbiter_inode_ctx_t *ctx = NULL;
    uint64_t ctx_addr = 0;

    inode_ctx_del(inode, this, &ctx_addr);
    if (!ctx_addr)
        return 0;
    ctx = (arbiter_inode_ctx_t *)(long)ctx_addr;
    GF_FREE(ctx);
    return 0;
}

int32_t
init(xlator_t *this)
{
    if (!this->children || this->children->next) {
        gf_log(this->name, GF_LOG_ERROR,
               "'arbiter' not configured with exactly one child");
        return -1;
    }

    if (!this->parents)
        gf_log(this->name, GF_LOG_ERROR, "dangling volume. check volfile ");

    return 0;
}

void
fini(xlator_t *this)
{
    return;
}

struct xlator_fops fops = {
    .lookup = arbiter_lookup,

    /* Return success for these inode write FOPS without winding it down to
     * posix; this is needed for AFR write transaction logic to work.*/
    .truncate = arbiter_truncate,
    .writev = arbiter_writev,
    .ftruncate = arbiter_ftruncate,
    .fallocate = arbiter_fallocate,
    .discard = arbiter_discard,
    .zerofill = arbiter_zerofill,

    /* AFR is not expected to wind these inode read FOPS initiated by the
     * application to the arbiter brick. But in case a bug causes them
     * to be called, we return ENOSYS. */
    .readv = arbiter_readv,
    .seek = arbiter_seek,

    /* The following inode read FOPS initiated by the application are not
     * wound by AFR either but internal logic like  shd, glfsheal and
     * client side healing in AFR will send them for selfheal/ inode refresh
     * operations etc.,so we need to wind them down to posix:
     *
     * (f)stat, readdir(p), readlink, (f)getxattr.*/

    /* All other FOPs not listed here are safe to be wound down to posix.*/
};

struct xlator_cbks cbks = {
    .forget = arbiter_forget,
};

struct volume_options options[] = {
    {.key = {NULL}},
};

xlator_api_t xlator_api = {
    .init = init,
    .fini = fini,
    .reconfigure = reconfigure,
    .mem_acct_init = mem_acct_init,
    .op_version = {1}, /* Present from the initial version */
    .fops = &fops,
    .cbks = &cbks,
    .options = options,
    .identifier = "arbiter",
    .category = GF_MAINTAINED,
};