/*
  Copyright (c) 2012-2014 DataLab, s.l. <http://www.datalab.es>
  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 "ec.h"
#include "ec-messages.h"
#include "ec-helpers.h"
#include "ec-common.h"
#include "ec-combine.h"
#include "ec-method.h"
#include "ec-fops.h"

/* FOP: access */

int32_t
ec_access_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
              int32_t op_errno, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_ACCESS, idx, op_ret,
                               op_errno);
    if (cbk) {
        if (xdata)
            cbk->xdata = dict_ref(xdata);
        ec_combine(cbk, NULL);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_access(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_access_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->access,
                      &fop->loc[0], fop->int32, fop->xdata);
}

int32_t
ec_manager_access(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk = NULL;

    switch (state) {
        case EC_STATE_INIT:
        case EC_STATE_LOCK:
            ec_lock_prepare_inode(fop, &fop->loc[0], EC_QUERY_INFO, 0,
                                  EC_RANGE_FULL);
            ec_lock(fop);

            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            ec_dispatch_one(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            if (ec_dispatch_one_retry(fop, NULL)) {
                return EC_STATE_DISPATCH;
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;
            GF_ASSERT(cbk);
            if (fop->cbks.access != NULL) {
                if (cbk) {
                    fop->cbks.access(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                     cbk->op_errno, cbk->xdata);
                }
            }
            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            if (fop->cbks.access != NULL) {
                fop->cbks.access(fop->req_frame, fop, fop->xl, -1, fop->error,
                                 NULL);
            }
            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_access(call_frame_t *frame, xlator_t *this, uintptr_t target,
          uint32_t fop_flags, fop_access_cbk_t func, void *data, loc_t *loc,
          int32_t mask, dict_t *xdata)
{
    ec_cbk_t callback = {.access = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(ACCESS) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_ACCESS, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_access,
                               ec_manager_access, callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->int32 = mask;

    if (loc != NULL) {
        if (loc_copy(&fop->loc[0], loc) != 0) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_LOC_COPY_FAIL,
                   "Failed to copy a location.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL);
    }
}

/* FOP: getxattr */

int32_t
ec_combine_getxattr(ec_fop_data_t *fop, ec_cbk_data_t *dst, ec_cbk_data_t *src)
{
    if (!ec_dict_compare(dst->dict, src->dict)) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_DICT_MISMATCH,
               "Mismatching dictionary in "
               "answers of 'GF_FOP_GETXATTR'");

        return 0;
    }

    return 1;
}

int32_t
ec_getxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                int32_t op_ret, int32_t op_errno, dict_t *dict, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_GETXATTR, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            if (dict != NULL) {
                cbk->dict = dict_ref(dict);
                if (cbk->dict == NULL) {
                    gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                           "Failed to reference a "
                           "dictionary.");

                    goto out;
                }
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        ec_combine(cbk, ec_combine_getxattr);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_getxattr(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_getxattr_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->getxattr,
                      &fop->loc[0], fop->str[0], fop->xdata);
}

void
ec_handle_special_xattrs(ec_fop_data_t *fop)
{
    ec_cbk_data_t *cbk = NULL;
    /* Stime may not be available on all the bricks, so even if some of the
     * subvols succeed the operation, treat it as answer.*/
    if (fop->str[0] && fnmatch(GF_XATTR_STIME_PATTERN, fop->str[0], 0) == 0) {
        if (!fop->answer || (fop->answer->op_ret < 0)) {
            list_for_each_entry(cbk, &fop->cbk_list, list)
            {
                if (cbk->op_ret >= 0) {
                    fop->answer = cbk;
                    break;
                }
            }
        }
    }
}

int32_t
ec_manager_getxattr(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk;

    switch (state) {
        case EC_STATE_INIT:
        case EC_STATE_LOCK:
            /* clear-locks commands must be done without any locks acquired
               to avoid interferences. */
            if ((fop->str[0] == NULL) ||
                (strncmp(fop->str[0], GF_XATTR_CLRLK_CMD,
                         SLEN(GF_XATTR_CLRLK_CMD)) != 0)) {
                if (fop->fd == NULL) {
                    ec_lock_prepare_inode(fop, &fop->loc[0], EC_QUERY_INFO, 0,
                                          EC_RANGE_FULL);
                } else {
                    ec_lock_prepare_fd(fop, fop->fd, EC_QUERY_INFO, 0,
                                       EC_RANGE_FULL);
                }
                ec_lock(fop);
            }

            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            if (fop->minimum == EC_MINIMUM_ALL) {
                ec_dispatch_all(fop);
            } else {
                ec_dispatch_one(fop);
            }

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            ec_handle_special_xattrs(fop);
            if (fop->minimum == EC_MINIMUM_ALL) {
                cbk = ec_fop_prepare_answer(fop, _gf_true);
            } else {
                if (ec_dispatch_one_retry(fop, &cbk)) {
                    return EC_STATE_DISPATCH;
                }
            }
            if (cbk != NULL) {
                int32_t err;

                err = ec_dict_combine(cbk, EC_COMBINE_DICT);
                if (!ec_cbk_set_error(cbk, -err, _gf_true)) {
                    if (cbk->xdata != NULL)
                        ec_filter_internal_xattrs(cbk->xdata);

                    if (cbk->dict != NULL)
                        ec_filter_internal_xattrs(cbk->dict);
                }
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;

            GF_ASSERT(cbk != NULL);

            if (fop->cbks.getxattr != NULL) {
                fop->cbks.getxattr(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                   cbk->op_errno, cbk->dict, cbk->xdata);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            GF_ASSERT(fop->error != 0);

            if (fop->cbks.getxattr != NULL) {
                fop->cbks.getxattr(fop->req_frame, fop, fop->xl, -1, fop->error,
                                   NULL, NULL);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

int32_t
ec_getxattr_heal_cbk(call_frame_t *frame, void *cookie, xlator_t *xl,
                     int32_t op_ret, int32_t op_errno, uintptr_t mask,
                     uintptr_t good, uintptr_t bad, dict_t *xdata)
{
    fop_getxattr_cbk_t func = cookie;
    ec_t *ec = xl->private;
    dict_t *dict = NULL;
    char *str;
    char bin1[65], bin2[65];

    if (op_ret >= 0) {
        dict = dict_new();
        if (dict == NULL) {
            op_ret = -1;
            op_errno = ENOMEM;
        } else {
            if (gf_asprintf(&str, "Good: %s, Bad: %s",
                            ec_bin(bin1, sizeof(bin1), good, ec->nodes),
                            ec_bin(bin2, sizeof(bin2), mask & ~(good | bad),
                                   ec->nodes)) < 0) {
                dict_unref(dict);
                dict = NULL;

                op_ret = -1;
                op_errno = ENOMEM;

                goto out;
            }

            if (dict_set_dynstr(dict, EC_XATTR_HEAL, str) != 0) {
                GF_FREE(str);
                dict_unref(dict);
                dict = NULL;

                op_ret = -1;
                op_errno = ENOMEM;

                goto out;
            }
        }
    }

out:
    func(frame, NULL, xl, op_ret, op_errno, dict, NULL);

    if (dict != NULL) {
        dict_unref(dict);
    }

    return 0;
}

void
ec_getxattr(call_frame_t *frame, xlator_t *this, uintptr_t target,
            uint32_t fop_flags, fop_getxattr_cbk_t func, void *data, loc_t *loc,
            const char *name, dict_t *xdata)
{
    ec_cbk_t callback = {.getxattr = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(GETXATTR) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    /* Special handling of an explicit self-heal request */
    if ((name != NULL) && (strcmp(name, EC_XATTR_HEAL) == 0)) {
        ec_heal(frame, this, target, EC_MINIMUM_ONE, ec_getxattr_heal_cbk, func,
                loc, 0, NULL);

        return;
    }

    fop = ec_fop_data_allocate(
        frame, this, GF_FOP_GETXATTR, EC_FLAG_LOCK_SHARED, target, fop_flags,
        ec_wind_getxattr, ec_manager_getxattr, callback, data);
    if (fop == NULL) {
        goto out;
    }

    if (loc != NULL) {
        if (loc_copy(&fop->loc[0], loc) != 0) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_LOC_COPY_FAIL,
                   "Failed to copy a location.");

            goto out;
        }
    }
    if (name != NULL) {
        /* In case of list-node-uuids xattr, set flag to indicate
         * the same and use node-uuid xattr for winding fop */
        if (XATTR_IS_NODE_UUID_LIST(name)) {
            fop->int32 = 1;
            fop->str[0] = gf_strdup(GF_XATTR_NODE_UUID_KEY);
        } else {
            fop->str[0] = gf_strdup(name);
        }
        if (fop->str[0] == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_NO_MEMORY,
                   "Failed to duplicate a string.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL);
    }
}

/* FOP: fgetxattr */

int32_t
ec_fgetxattr_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                 int32_t op_ret, int32_t op_errno, dict_t *dict, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_FGETXATTR, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            if (dict != NULL) {
                cbk->dict = dict_ref(dict);
                if (cbk->dict == NULL) {
                    gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                           "Failed to reference a "
                           "dictionary.");

                    goto out;
                }
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        ec_combine(cbk, ec_combine_getxattr);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_fgetxattr(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_fgetxattr_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->fgetxattr,
                      fop->fd, fop->str[0], fop->xdata);
}

void
ec_fgetxattr(call_frame_t *frame, xlator_t *this, uintptr_t target,
             uint32_t fop_flags, fop_fgetxattr_cbk_t func, void *data, fd_t *fd,
             const char *name, dict_t *xdata)
{
    ec_cbk_t callback = {.fgetxattr = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(FGETXATTR) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(
        frame, this, GF_FOP_FGETXATTR, EC_FLAG_LOCK_SHARED, target, fop_flags,
        ec_wind_fgetxattr, ec_manager_getxattr, callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->use_fd = 1;

    if (fd != NULL) {
        fop->fd = fd_ref(fd);
        if (fop->fd == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_FILE_DESC_REF_FAIL,
                   "Failed to reference a "
                   "file descriptor.");

            goto out;
        }
    }
    if (name != NULL) {
        fop->str[0] = gf_strdup(name);
        if (fop->str[0] == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_NO_MEMORY,
                   "Failed to duplicate a string.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL);
    }
}

/* FOP: open */

int32_t
ec_combine_open(ec_fop_data_t *fop, ec_cbk_data_t *dst, ec_cbk_data_t *src)
{
    if (dst->fd != src->fd) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_FD_MISMATCH,
               "Mismatching fd in answers "
               "of 'GF_FOP_OPEN': %p <-> %p",
               dst->fd, src->fd);

        return 0;
    }

    return 1;
}

int32_t
ec_open_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
            int32_t op_errno, fd_t *fd, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_OPEN, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            if (fd != NULL) {
                cbk->fd = fd_ref(fd);
                if (cbk->fd == NULL) {
                    gf_msg(this->name, GF_LOG_ERROR, 0,
                           EC_MSG_FILE_DESC_REF_FAIL,
                           "Failed to reference a "
                           "file descriptor.");

                    goto out;
                }
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        ec_combine(cbk, ec_combine_open);

        ec_update_fd_status(fd, this, idx, op_ret);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_open(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_open_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->open,
                      &fop->loc[0], fop->int32, fop->fd, fop->xdata);
}

int32_t
ec_open_truncate_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                     int32_t op_ret, int32_t op_errno, struct iatt *prebuf,
                     struct iatt *postbuf, dict_t *xdata)
{
    ec_fop_data_t *fop = cookie;
    int32_t error = 0;

    fop = fop->data;
    if (op_ret >= 0) {
        fop->answer->iatt[0] = *postbuf;
    } else {
        error = op_errno;
    }

    ec_resume(fop, error);

    return 0;
}

int32_t
ec_manager_open(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk;
    ec_fd_t *ctx;
    int32_t err;

    switch (state) {
        case EC_STATE_INIT:
            LOCK(&fop->fd->lock);

            ctx = __ec_fd_get(fop->fd, fop->xl);
            if (ctx == NULL) {
                UNLOCK(&fop->fd->lock);

                fop->error = ENOMEM;

                return EC_STATE_REPORT;
            }
            if (!ctx->loc.inode) {
                err = ec_loc_from_loc(fop->xl, &ctx->loc, &fop->loc[0]);
                if (err != 0) {
                    UNLOCK(&fop->fd->lock);

                    fop->error = -err;

                    return EC_STATE_REPORT;
                }
            }

            ctx->flags = fop->int32;

            UNLOCK(&fop->fd->lock);

            /* We need to write to specific offsets on the bricks, so we
               need to remove O_APPEND from flags (if present).
               If O_TRUNC is specified, we remove it from open and an
               ftruncate will be executed later, which will correctly update
               the file size taking appropriate locks. O_TRUNC flag is saved
               into fop->uint32 to use it later.*/
            fop->uint32 = fop->int32 & O_TRUNC;
            fop->int32 &= ~(O_APPEND | O_TRUNC);

            /* Fall through */

        case EC_STATE_DISPATCH:
            ec_dispatch_all(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            cbk = ec_fop_prepare_answer(fop, _gf_true);
            if (cbk != NULL) {
                int32_t err;

                err = ec_loc_update(fop->xl, &fop->loc[0], cbk->fd->inode,
                                    NULL);
                if (!ec_cbk_set_error(cbk, -err, _gf_true)) {
                    LOCK(&fop->fd->lock);

                    ctx = __ec_fd_get(fop->fd, fop->xl);
                    if (ctx != NULL) {
                        ctx->open |= cbk->mask;
                    }

                    UNLOCK(&fop->fd->lock);

                    /* If O_TRUNC was specified, call ftruncate to
                       effectively trunc the file with appropriate locks
                       acquired. We don't use ctx->flags because self-heal
                       can use the same fd with different flags. */
                    if (fop->uint32 != 0) {
                        ec_sleep(fop);
                        ec_ftruncate(fop->req_frame, fop->xl, cbk->mask,
                                     fop->minimum, ec_open_truncate_cbk, fop,
                                     cbk->fd, 0, NULL);
                    }
                }
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;

            GF_ASSERT(cbk != NULL);

            if (fop->cbks.open != NULL) {
                fop->cbks.open(fop->req_frame, fop, fop->xl, cbk->op_ret,
                               cbk->op_errno, cbk->fd, cbk->xdata);
            }

            return EC_STATE_END;

        case -EC_STATE_INIT:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            GF_ASSERT(fop->error != 0);

            if (fop->cbks.open != NULL) {
                fop->cbks.open(fop->req_frame, fop, fop->xl, -1, fop->error,
                               NULL, NULL);
            }

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_open(call_frame_t *frame, xlator_t *this, uintptr_t target,
        uint32_t fop_flags, fop_open_cbk_t func, void *data, loc_t *loc,
        int32_t flags, fd_t *fd, dict_t *xdata)
{
    ec_cbk_t callback = {.open = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(OPEN) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_OPEN, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_open, ec_manager_open,
                               callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->int32 = flags;

    if (loc != NULL) {
        if (loc_copy(&fop->loc[0], loc) != 0) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_LOC_COPY_FAIL,
                   "Failed to copy a location.");

            goto out;
        }
    }
    if (fd != NULL) {
        fop->fd = fd_ref(fd);
        if (fop->fd == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_FILE_DESC_REF_FAIL,
                   "Failed to reference a "
                   "file descriptor.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL);
    }
}

/* FOP: readlink */

int32_t
ec_combine_readlink(ec_fop_data_t *fop, ec_cbk_data_t *dst, ec_cbk_data_t *src)
{
    if (!ec_iatt_combine(fop, dst->iatt, src->iatt, 1)) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_IATT_MISMATCH,
               "Mismatching iatt in "
               "answers of 'GF_FOP_READLINK'");

        return 0;
    }

    return 1;
}

int32_t
ec_readlink_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
                int32_t op_ret, int32_t op_errno, const char *path,
                struct iatt *buf, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, fop->id, idx, op_ret,
                               op_errno);
    if (cbk) {
        if (xdata)
            cbk->xdata = dict_ref(xdata);

        if (cbk->op_ret >= 0) {
            cbk->iatt[0] = *buf;
            cbk->str = gf_strdup(path);
            if (!cbk->str) {
                ec_cbk_set_error(cbk, ENOMEM, _gf_true);
            }
        }
        ec_combine(cbk, NULL);
    }

out:
    if (fop != NULL)
        ec_complete(fop);

    return 0;
}

void
ec_wind_readlink(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_readlink_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->readlink,
                      &fop->loc[0], fop->size, fop->xdata);
}

int32_t
ec_manager_readlink(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk = NULL;

    switch (state) {
        case EC_STATE_INIT:
        case EC_STATE_LOCK:
            ec_lock_prepare_inode(fop, &fop->loc[0], EC_QUERY_INFO, 0,
                                  EC_RANGE_FULL);
            ec_lock(fop);
            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            ec_dispatch_one(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            if (ec_dispatch_one_retry(fop, &cbk)) {
                return EC_STATE_DISPATCH;
            }

            if ((cbk != NULL) && (cbk->op_ret >= 0)) {
                ec_iatt_rebuild(fop->xl->private, &cbk->iatt[0], 1, 1);
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;
            GF_ASSERT(cbk);
            if (fop->cbks.readlink != NULL) {
                fop->cbks.readlink(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                   cbk->op_errno, cbk->str, &cbk->iatt[0],
                                   cbk->xdata);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            if (fop->cbks.readlink != NULL) {
                fop->cbks.readlink(fop->req_frame, fop, fop->xl, -1, fop->error,
                                   NULL, NULL, NULL);
            }
            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;
        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_readlink(call_frame_t *frame, xlator_t *this, uintptr_t target,
            uint32_t fop_flags, fop_readlink_cbk_t func, void *data, loc_t *loc,
            size_t size, dict_t *xdata)
{
    ec_cbk_t callback = {.readlink = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(READLINK) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(
        frame, this, GF_FOP_READLINK, EC_FLAG_LOCK_SHARED, target, fop_flags,
        ec_wind_readlink, ec_manager_readlink, callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->size = size;

    if (loc != NULL) {
        if (loc_copy(&fop->loc[0], loc) != 0) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_LOC_COPY_FAIL,
                   "Failed to copy a location.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL, NULL);
    }
}

/* FOP: readv */

int32_t
ec_readv_rebuild(ec_t *ec, ec_fop_data_t *fop, ec_cbk_data_t *cbk)
{
    struct iovec vector[1];
    ec_cbk_data_t *ans = NULL;
    struct iobref *iobref = NULL;
    void *ptr;
    uint64_t fsize = 0, size = 0, max = 0;
    int32_t pos, err = -ENOMEM;

    if (cbk->op_ret < 0) {
        err = -cbk->op_errno;

        goto out;
    }

    /* This shouldn't fail because we have the inode locked. */
    GF_ASSERT(ec_get_inode_size(fop, fop->fd->inode, &cbk->iatt[0].ia_size));

    if (cbk->op_ret > 0) {
        void *blocks[cbk->count];
        uint32_t values[cbk->count];

        fsize = cbk->op_ret;
        size = fsize * ec->fragments;
        for (ans = cbk; ans != NULL; ans = ans->next) {
            pos = gf_bits_count(cbk->mask & ((1 << ans->idx) - 1));
            values[pos] = ans->idx + 1;
            blocks[pos] = ans->vector[0].iov_base;
            if ((ans->int32 != 1) ||
                !EC_ALIGN_CHECK(blocks[pos], EC_METHOD_WORD_SIZE)) {
                if (iobref == NULL) {
                    err = ec_buffer_alloc(ec->xl, size, &iobref, &ptr);
                    if (err != 0) {
                        goto out;
                    }
                }
                ec_iov_copy_to(ptr, ans->vector, ans->int32, 0, fsize);
                blocks[pos] = ptr;
                ptr += fsize;
            }
        }

        err = ec_buffer_alloc(ec->xl, size, &iobref, &ptr);
        if (err != 0) {
            goto out;
        }

        err = ec_method_decode(&ec->matrix, fsize, cbk->mask, values, blocks,
                               ptr);
        if (err != 0) {
            goto out;
        }

        vector[0].iov_base = ptr + fop->head;
        vector[0].iov_len = size - fop->head;

        max = fop->offset * ec->fragments + size;
        if (max > cbk->iatt[0].ia_size) {
            max = cbk->iatt[0].ia_size;
        }
        max -= fop->offset * ec->fragments + fop->head;
        if (max > fop->user_size) {
            max = fop->user_size;
        }
        size -= fop->head;
        if (size > max) {
            vector[0].iov_len -= size - max;
            size = max;
        }

        cbk->op_ret = size;
        cbk->int32 = 1;

        iobref_unref(cbk->buffers);
        cbk->buffers = iobref;

        GF_FREE(cbk->vector);
        cbk->vector = iov_dup(vector, 1);
        if (cbk->vector == NULL) {
            return -ENOMEM;
        }
    }

    return 0;

out:
    if (iobref != NULL) {
        iobref_unref(iobref);
    }

    return err;
}

int32_t
ec_combine_readv(ec_fop_data_t *fop, ec_cbk_data_t *dst, ec_cbk_data_t *src)
{
    if (!ec_vector_compare(dst->vector, dst->int32, src->vector, src->int32)) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_VECTOR_MISMATCH,
               "Mismatching vector in "
               "answers of 'GF_FOP_READ'");

        return 0;
    }

    if (!ec_iatt_combine(fop, dst->iatt, src->iatt, 1)) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_IATT_MISMATCH,
               "Mismatching iatt in "
               "answers of 'GF_FOP_READ'");

        return 0;
    }

    return 1;
}

int32_t
ec_readv_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
             int32_t op_errno, struct iovec *vector, int32_t count,
             struct iatt *stbuf, struct iobref *iobref, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    ec_t *ec = this->private;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_READ, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            cbk->int32 = count;

            if (count > 0) {
                cbk->vector = iov_dup(vector, count);
                if (cbk->vector == NULL) {
                    gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_NO_MEMORY,
                           "Failed to duplicate a "
                           "vector list.");

                    goto out;
                }
                cbk->int32 = count;
            }
            if (stbuf != NULL) {
                cbk->iatt[0] = *stbuf;
            }
            if (iobref != NULL) {
                cbk->buffers = iobref_ref(iobref);
                if (cbk->buffers == NULL) {
                    gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_BUF_REF_FAIL,
                           "Failed to reference a "
                           "buffer.");

                    goto out;
                }
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        if ((op_ret > 0) && ((op_ret % ec->fragment_size) != 0)) {
            ec_cbk_set_error(cbk, EIO, _gf_true);
        }

        ec_combine(cbk, ec_combine_readv);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_readv(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_readv_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->readv, fop->fd,
                      fop->size, fop->offset, fop->uint32, fop->xdata);
}

int32_t
ec_manager_readv(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk;
    ec_t *ec = fop->xl->private;

    switch (state) {
        case EC_STATE_INIT:
            fop->user_size = fop->size;
            fop->head = ec_adjust_offset_down(fop->xl->private, &fop->offset,
                                              _gf_true);
            fop->size += fop->head;
            ec_adjust_size_up(fop->xl->private, &fop->size, _gf_true);

            /* Fall through */

        case EC_STATE_LOCK:
            ec_lock_prepare_fd(fop, fop->fd, EC_QUERY_INFO, fop->offset,
                               fop->size);
            ec_lock(fop);

            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            if (ec->read_mask) {
                fop->mask &= ec->read_mask;
            }
            ec_dispatch_min(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            cbk = ec_fop_prepare_answer(fop, _gf_true);
            if (cbk != NULL) {
                int32_t err;

                ec_iatt_rebuild(fop->xl->private, cbk->iatt, 1, cbk->count);

                err = ec_readv_rebuild(fop->xl->private, fop, cbk);
                if (err != 0) {
                    ec_cbk_set_error(cbk, -err, _gf_true);
                }
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;

            GF_ASSERT(cbk != NULL);

            if (fop->cbks.readv != NULL) {
                fop->cbks.readv(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                cbk->op_errno, cbk->vector, cbk->int32,
                                &cbk->iatt[0], cbk->buffers, cbk->xdata);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            GF_ASSERT(fop->error != 0);

            if (fop->cbks.readv != NULL) {
                fop->cbks.readv(fop->req_frame, fop, fop->xl, -1, fop->error,
                                NULL, 0, NULL, NULL, NULL);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_readv(call_frame_t *frame, xlator_t *this, uintptr_t target,
         uint32_t fop_flags, fop_readv_cbk_t func, void *data, fd_t *fd,
         size_t size, off_t offset, uint32_t flags, dict_t *xdata)
{
    ec_cbk_t callback = {.readv = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(READ) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_READ, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_readv,
                               ec_manager_readv, callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->use_fd = 1;

    fop->size = size;
    fop->offset = offset;
    fop->uint32 = flags;

    if (fd != NULL) {
        fop->fd = fd_ref(fd);
        if (fop->fd == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_FILE_DESC_REF_FAIL,
                   "Failed to reference a "
                   "file descriptor.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, 0, NULL, NULL, NULL);
    }
}

/* FOP: seek */

int32_t
ec_seek_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
            int32_t op_errno, off_t offset, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    ec_t *ec = this->private;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_SEEK, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            cbk->offset = offset;
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
        }

        if ((op_ret > 0) && ((cbk->offset % ec->fragment_size) != 0)) {
            cbk->op_ret = -1;
            cbk->op_errno = EIO;
        }

        ec_combine(cbk, NULL);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_seek(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_seek_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->seek, fop->fd,
                      fop->offset, fop->seek, fop->xdata);
}

int32_t
ec_manager_seek(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk;
    uint64_t size;

    switch (state) {
        case EC_STATE_INIT:
            fop->user_size = fop->offset;
            fop->head = ec_adjust_offset_down(fop->xl->private, &fop->offset,
                                              _gf_true);

            /* Fall through */

        case EC_STATE_LOCK:
            ec_lock_prepare_fd(fop, fop->fd, EC_QUERY_INFO, fop->offset,
                               EC_RANGE_FULL);
            ec_lock(fop);

            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            /* This shouldn't fail because we have the inode locked. */
            GF_ASSERT(
                ec_get_inode_size(fop, fop->locks[0].lock->loc.inode, &size));

            if (fop->user_size >= size) {
                ec_fop_set_error(fop, ENXIO);

                return EC_STATE_REPORT;
            }

            ec_dispatch_one(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            if (ec_dispatch_one_retry(fop, &cbk)) {
                return EC_STATE_DISPATCH;
            }
            if ((cbk != NULL) && (cbk->op_ret >= 0)) {
                ec_t *ec = fop->xl->private;

                /* This shouldn't fail because we have the inode locked. */
                GF_ASSERT(ec_get_inode_size(fop, fop->locks[0].lock->loc.inode,
                                            &size));

                cbk->offset *= ec->fragments;
                if (cbk->offset < fop->user_size) {
                    cbk->offset = fop->user_size;
                }
                if (cbk->offset > size) {
                    cbk->offset = size;
                }
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;

            GF_ASSERT(cbk != NULL);

            if (fop->cbks.seek != NULL) {
                fop->cbks.seek(fop->req_frame, fop, fop->xl, cbk->op_ret,
                               cbk->op_errno, cbk->offset, cbk->xdata);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            GF_ASSERT(fop->error != 0);

            if (fop->cbks.seek != NULL) {
                fop->cbks.seek(fop->req_frame, fop, fop->xl, -1, fop->error, 0,
                               NULL);
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, 0, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_seek(call_frame_t *frame, xlator_t *this, uintptr_t target,
        uint32_t fop_flags, fop_seek_cbk_t func, void *data, fd_t *fd,
        off_t offset, gf_seek_what_t what, dict_t *xdata)
{
    ec_cbk_t callback = {.seek = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = EIO;

    gf_msg_trace("ec", 0, "EC(SEEK) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_SEEK, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_seek, ec_manager_seek,
                               callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->use_fd = 1;

    fop->offset = offset;
    fop->seek = what;

    if (fd != NULL) {
        fop->fd = fd_ref(fd);
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, EIO, 0, NULL);
    }
}

/* FOP: stat */

int32_t
ec_combine_stat(ec_fop_data_t *fop, ec_cbk_data_t *dst, ec_cbk_data_t *src)
{
    if (!ec_iatt_combine(fop, dst->iatt, src->iatt, 1)) {
        gf_msg(fop->xl->name, GF_LOG_NOTICE, 0, EC_MSG_IATT_MISMATCH,
               "Mismatching iatt in "
               "answers of 'GF_FOP_STAT'");

        return 0;
    }

    return 1;
}

int32_t
ec_stat_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
            int32_t op_errno, struct iatt *buf, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_STAT, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            if (buf != NULL) {
                cbk->iatt[0] = *buf;
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        ec_combine(cbk, ec_combine_stat);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_stat(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_stat_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->stat,
                      &fop->loc[0], fop->xdata);
}

int32_t
ec_manager_stat(ec_fop_data_t *fop, int32_t state)
{
    ec_cbk_data_t *cbk;

    switch (state) {
        case EC_STATE_INIT:
        case EC_STATE_LOCK:
            if (fop->fd == NULL) {
                ec_lock_prepare_inode(fop, &fop->loc[0], EC_QUERY_INFO, 0,
                                      EC_RANGE_FULL);
            } else {
                ec_lock_prepare_fd(fop, fop->fd, EC_QUERY_INFO, 0,
                                   EC_RANGE_FULL);
            }
            ec_lock(fop);

            return EC_STATE_DISPATCH;

        case EC_STATE_DISPATCH:
            ec_dispatch_all(fop);

            return EC_STATE_PREPARE_ANSWER;

        case EC_STATE_PREPARE_ANSWER:
            cbk = ec_fop_prepare_answer(fop, _gf_true);

            if (cbk != NULL) {
                if (cbk->iatt[0].ia_type == IA_IFREG) {
                    ec_iatt_rebuild(fop->xl->private, cbk->iatt, 1, cbk->count);

                    /* This shouldn't fail because we have the inode locked. */
                    GF_ASSERT(ec_get_inode_size(fop,
                                                fop->locks[0].lock->loc.inode,
                                                &cbk->iatt[0].ia_size));
                }
            }

            return EC_STATE_REPORT;

        case EC_STATE_REPORT:
            cbk = fop->answer;

            GF_ASSERT(cbk != NULL);

            if (fop->id == GF_FOP_STAT) {
                if (fop->cbks.stat != NULL) {
                    fop->cbks.stat(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                   cbk->op_errno, &cbk->iatt[0], cbk->xdata);
                }
            } else {
                if (fop->cbks.fstat != NULL) {
                    fop->cbks.fstat(fop->req_frame, fop, fop->xl, cbk->op_ret,
                                    cbk->op_errno, &cbk->iatt[0], cbk->xdata);
                }
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_INIT:
        case -EC_STATE_LOCK:
        case -EC_STATE_DISPATCH:
        case -EC_STATE_PREPARE_ANSWER:
        case -EC_STATE_REPORT:
            GF_ASSERT(fop->error != 0);

            if (fop->id == GF_FOP_STAT) {
                if (fop->cbks.stat != NULL) {
                    fop->cbks.stat(fop->req_frame, fop, fop->xl, -1, fop->error,
                                   NULL, NULL);
                }
            } else {
                if (fop->cbks.fstat != NULL) {
                    fop->cbks.fstat(fop->req_frame, fop, fop->xl, -1,
                                    fop->error, NULL, NULL);
                }
            }

            return EC_STATE_LOCK_REUSE;

        case -EC_STATE_LOCK_REUSE:
        case EC_STATE_LOCK_REUSE:
            ec_lock_reuse(fop);

            return EC_STATE_UNLOCK;

        case -EC_STATE_UNLOCK:
        case EC_STATE_UNLOCK:
            ec_unlock(fop);

            return EC_STATE_END;

        default:
            gf_msg(fop->xl->name, GF_LOG_ERROR, EINVAL, EC_MSG_UNHANDLED_STATE,
                   "Unhandled state %d for %s", state, ec_fop_name(fop->id));

            return EC_STATE_END;
    }
}

void
ec_stat(call_frame_t *frame, xlator_t *this, uintptr_t target,
        uint32_t fop_flags, fop_stat_cbk_t func, void *data, loc_t *loc,
        dict_t *xdata)
{
    ec_cbk_t callback = {.stat = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(STAT) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_STAT, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_stat, ec_manager_stat,
                               callback, data);
    if (fop == NULL) {
        goto out;
    }

    if (loc != NULL) {
        if (loc_copy(&fop->loc[0], loc) != 0) {
            gf_msg(this->name, GF_LOG_ERROR, ENOMEM, EC_MSG_LOC_COPY_FAIL,
                   "Failed to copy a location.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL);
    }
}

/* FOP: fstat */

int32_t
ec_fstat_cbk(call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
             int32_t op_errno, struct iatt *buf, dict_t *xdata)
{
    ec_fop_data_t *fop = NULL;
    ec_cbk_data_t *cbk = NULL;
    int32_t idx = (int32_t)(uintptr_t)cookie;

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, frame->local, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = frame->local;

    ec_trace("CBK", fop, "idx=%d, frame=%p, op_ret=%d, op_errno=%d", idx, frame,
             op_ret, op_errno);

    cbk = ec_cbk_data_allocate(frame, this, fop, GF_FOP_FSTAT, idx, op_ret,
                               op_errno);
    if (cbk != NULL) {
        if (op_ret >= 0) {
            if (buf != NULL) {
                cbk->iatt[0] = *buf;
            }
        }
        if (xdata != NULL) {
            cbk->xdata = dict_ref(xdata);
            if (cbk->xdata == NULL) {
                gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                       "Failed to reference a "
                       "dictionary.");

                goto out;
            }
        }

        ec_combine(cbk, ec_combine_stat);
    }

out:
    if (fop != NULL) {
        ec_complete(fop);
    }

    return 0;
}

void
ec_wind_fstat(ec_t *ec, ec_fop_data_t *fop, int32_t idx)
{
    ec_trace("WIND", fop, "idx=%d", idx);

    STACK_WIND_COOKIE(fop->frame, ec_fstat_cbk, (void *)(uintptr_t)idx,
                      ec->xl_list[idx], ec->xl_list[idx]->fops->fstat, fop->fd,
                      fop->xdata);
}

void
ec_fstat(call_frame_t *frame, xlator_t *this, uintptr_t target,
         uint32_t fop_flags, fop_fstat_cbk_t func, void *data, fd_t *fd,
         dict_t *xdata)
{
    ec_cbk_t callback = {.fstat = func};
    ec_fop_data_t *fop = NULL;
    int32_t error = ENOMEM;

    gf_msg_trace("ec", 0, "EC(FSTAT) %p", frame);

    VALIDATE_OR_GOTO(this, out);
    GF_VALIDATE_OR_GOTO(this->name, frame, out);
    GF_VALIDATE_OR_GOTO(this->name, this->private, out);

    fop = ec_fop_data_allocate(frame, this, GF_FOP_FSTAT, EC_FLAG_LOCK_SHARED,
                               target, fop_flags, ec_wind_fstat,
                               ec_manager_stat, callback, data);
    if (fop == NULL) {
        goto out;
    }

    fop->use_fd = 1;

    if (fd != NULL) {
        fop->fd = fd_ref(fd);
        if (fop->fd == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_FILE_DESC_REF_FAIL,
                   "Failed to reference a "
                   "file descriptor.");

            goto out;
        }
    }
    if (xdata != NULL) {
        fop->xdata = dict_ref(xdata);
        if (fop->xdata == NULL) {
            gf_msg(this->name, GF_LOG_ERROR, 0, EC_MSG_DICT_REF_FAIL,
                   "Failed to reference a "
                   "dictionary.");

            goto out;
        }
    }

    error = 0;

out:
    if (fop != NULL) {
        ec_manager(fop, error);
    } else {
        func(frame, NULL, this, -1, error, NULL, NULL);
    }
}