/*
  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 "glusterfs/syncop.h"
#include "glusterfs/syncop-utils.h"
#include "glusterfs/common-utils.h"
#include "glusterfs/libglusterfs-messages.h"

struct syncop_dir_scan_data {
    xlator_t *subvol;
    loc_t *parent;
    void *data;
    gf_dirent_t *q;
    gf_dirent_t *entry;
    pthread_cond_t *cond;
    pthread_mutex_t *mut;
    syncop_dir_scan_fn_t fn;
    uint32_t *jobs_running;
    uint32_t *qlen;
    int32_t *retval;
};

int
syncop_dirfd(xlator_t *subvol, loc_t *loc, fd_t **fd, int pid)
{
    int ret = 0;
    fd_t *dirfd = NULL;

    if (!fd)
        return -EINVAL;

    dirfd = fd_create(loc->inode, pid);
    if (!dirfd) {
        gf_msg(subvol->name, GF_LOG_ERROR, errno, LG_MSG_FD_CREATE_FAILED,
               "fd_create of %s", uuid_utoa(loc->gfid));
        ret = -errno;
        goto out;
    }

    ret = syncop_opendir(subvol, loc, dirfd, NULL, NULL);
    if (ret) {
        /*
         * On Linux, if the brick was not updated, opendir will
         * fail. We therefore use backward compatible code
         * that violate the standards by reusing offsets
         * in seekdir() from different DIR *, but it works on Linux.
         *
         * On other systems it never worked, hence we do not need
         * to provide backward-compatibility.
         */
#ifdef GF_LINUX_HOST_OS
        fd_unref(dirfd);
        dirfd = fd_anonymous(loc->inode);
        if (!dirfd) {
            gf_msg(subvol->name, GF_LOG_ERROR, errno,
                   LG_MSG_FD_ANONYMOUS_FAILED,
                   "fd_anonymous of "
                   "%s",
                   uuid_utoa(loc->gfid));
            ret = -errno;
            goto out;
        }
        ret = 0;
#else  /* GF_LINUX_HOST_OS */
        fd_unref(dirfd);
        gf_msg(subvol->name, GF_LOG_ERROR, errno, LG_MSG_DIR_OP_FAILED,
               "opendir of %s", uuid_utoa(loc->gfid));
        goto out;
#endif /* GF_LINUX_HOST_OS */
    } else {
        fd_bind(dirfd);
    }
out:
    if (ret == 0)
        *fd = dirfd;
    return ret;
}

int
syncop_ftw(xlator_t *subvol, loc_t *loc, int pid, void *data,
           int (*fn)(xlator_t *subvol, gf_dirent_t *entry, loc_t *parent,
                     void *data))
{
    loc_t child_loc = {
        0,
    };
    fd_t *fd = NULL;
    uint64_t offset = 0;
    gf_dirent_t *entry = NULL;
    int ret = 0;
    gf_dirent_t entries;

    ret = syncop_dirfd(subvol, loc, &fd, pid);
    if (ret)
        goto out;

    INIT_LIST_HEAD(&entries.list);

    while ((ret = syncop_readdirp(subvol, fd, 131072, offset, &entries, NULL,
                                  NULL))) {
        if (ret < 0)
            break;

        if (ret > 0) {
            /* If the entries are only '.', and '..' then ret
             * value will be non-zero. so set it to zero here. */
            ret = 0;
        }
        list_for_each_entry(entry, &entries.list, list)
        {
            offset = entry->d_off;

            if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
                continue;

            gf_link_inode_from_dirent(NULL, fd->inode, entry);

            ret = fn(subvol, entry, loc, data);
            if (ret)
                break;

            if (entry->d_stat.ia_type == IA_IFDIR) {
                child_loc.inode = inode_ref(entry->inode);
                gf_uuid_copy(child_loc.gfid, entry->inode->gfid);
                ret = syncop_ftw(subvol, &child_loc, pid, data, fn);
                loc_wipe(&child_loc);
                if (ret)
                    break;
            }
        }

        gf_dirent_free(&entries);
        if (ret)
            break;
    }

out:
    if (fd)
        fd_unref(fd);
    return ret;
}

/**
 * Syncop_ftw_throttle can be used in a configurable way to control
 * the speed at which crawling is done. It takes 2 more arguments
 * compared to syncop_ftw.
 * After @count entries are finished in a directory (to be
 * precise, @count files) sleep for @sleep_time seconds.
 * If either @count or @sleep_time is <=0, then it behaves similar to
 * syncop_ftw.
 */
int
syncop_ftw_throttle(xlator_t *subvol, loc_t *loc, int pid, void *data,
                    int (*fn)(xlator_t *subvol, gf_dirent_t *entry,
                              loc_t *parent, void *data),
                    int count, int sleep_time)
{
    loc_t child_loc = {
        0,
    };
    fd_t *fd = NULL;
    uint64_t offset = 0;
    gf_dirent_t *entry = NULL;
    int ret = 0;
    gf_dirent_t entries;
    int tmp = 0;

    if (sleep_time <= 0) {
        ret = syncop_ftw(subvol, loc, pid, data, fn);
        goto out;
    }

    ret = syncop_dirfd(subvol, loc, &fd, pid);
    if (ret)
        goto out;

    INIT_LIST_HEAD(&entries.list);

    while ((ret = syncop_readdirp(subvol, fd, 131072, offset, &entries, NULL,
                                  NULL))) {
        if (ret < 0)
            break;

        if (ret > 0) {
            /* If the entries are only '.', and '..' then ret
             * value will be non-zero. so set it to zero here. */
            ret = 0;
        }

        tmp = 0;

        list_for_each_entry(entry, &entries.list, list)
        {
            offset = entry->d_off;

            if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
                continue;

            if (++tmp >= count) {
                tmp = 0;
                sleep(sleep_time);
            }

            gf_link_inode_from_dirent(NULL, fd->inode, entry);

            ret = fn(subvol, entry, loc, data);
            if (ret)
                continue;

            if (entry->d_stat.ia_type == IA_IFDIR) {
                child_loc.inode = inode_ref(entry->inode);
                gf_uuid_copy(child_loc.gfid, entry->inode->gfid);
                ret = syncop_ftw_throttle(subvol, &child_loc, pid, data, fn,
                                          count, sleep_time);
                loc_wipe(&child_loc);
                if (ret)
                    continue;
            }
        }

        gf_dirent_free(&entries);
        if (ret)
            break;
    }

out:
    if (fd)
        fd_unref(fd);
    return ret;
}

static void
_scan_data_destroy(struct syncop_dir_scan_data *data)
{
    GF_FREE(data);
}

static int
_dir_scan_job_fn_cbk(int ret, call_frame_t *frame, void *opaque)
{
    struct syncop_dir_scan_data *scan_data = opaque;

    _scan_data_destroy(scan_data);
    return 0;
}

static int
_dir_scan_job_fn(void *data)
{
    struct syncop_dir_scan_data *scan_data = data;
    gf_dirent_t *entry = NULL;
    int ret = 0;

    entry = scan_data->entry;
    scan_data->entry = NULL;
    do {
        ret = scan_data->fn(scan_data->subvol, entry, scan_data->parent,
                            scan_data->data);
        gf_dirent_entry_free(entry);
        entry = NULL;
        pthread_mutex_lock(scan_data->mut);
        {
            if (ret)
                *scan_data->retval |= ret;
            if (list_empty(&scan_data->q->list)) {
                (*scan_data->jobs_running)--;
                pthread_cond_broadcast(scan_data->cond);
            } else {
                entry = list_first_entry(&scan_data->q->list,
                                         typeof(*scan_data->q), list);
                list_del_init(&entry->list);
                (*scan_data->qlen)--;
            }
        }
        pthread_mutex_unlock(scan_data->mut);
    } while (entry);

    return ret;
}

static int
_run_dir_scan_task(call_frame_t *frame, xlator_t *subvol, loc_t *parent,
                   gf_dirent_t *q, gf_dirent_t *entry, int *retval,
                   pthread_mutex_t *mut, pthread_cond_t *cond,
                   uint32_t *jobs_running, uint32_t *qlen,
                   syncop_dir_scan_fn_t fn, void *data)
{
    int ret = 0;
    struct syncop_dir_scan_data *scan_data = NULL;

    scan_data = GF_CALLOC(1, sizeof(struct syncop_dir_scan_data),
                          gf_common_mt_scan_data);
    if (!scan_data) {
        ret = -ENOMEM;
        goto out;
    }

    scan_data->subvol = subvol;
    scan_data->parent = parent;
    scan_data->data = data;
    scan_data->mut = mut;
    scan_data->cond = cond;
    scan_data->fn = fn;
    scan_data->jobs_running = jobs_running;
    scan_data->entry = entry;
    scan_data->q = q;
    scan_data->qlen = qlen;
    scan_data->retval = retval;

    ret = synctask_new(subvol->ctx->env, _dir_scan_job_fn, _dir_scan_job_fn_cbk,
                       frame, scan_data);
out:
    if (ret < 0) {
        gf_dirent_entry_free(entry);
        _scan_data_destroy(scan_data);
        pthread_mutex_lock(mut);
        {
            *jobs_running = *jobs_running - 1;
        }
        pthread_mutex_unlock(mut);
        /*No need to cond-broadcast*/
    }
    return ret;
}

int
syncop_mt_dir_scan(call_frame_t *frame, xlator_t *subvol, loc_t *loc, int pid,
                   void *data, syncop_dir_scan_fn_t fn, dict_t *xdata,
                   uint32_t max_jobs, uint32_t max_qlen)
{
    fd_t *fd = NULL;
    uint64_t offset = 0;
    gf_dirent_t *last = NULL;
    int ret = 0;
    int retval = 0;
    gf_dirent_t q;
    gf_dirent_t *entry = NULL;
    gf_dirent_t *tmp = NULL;
    uint32_t jobs_running = 0;
    uint32_t qlen = 0;
    pthread_cond_t cond;
    pthread_mutex_t mut;
    gf_boolean_t cond_init = _gf_false;
    gf_boolean_t mut_init = _gf_false;
    gf_dirent_t entries;

    /*For this functionality to be implemented in general, we need
     * synccond_t infra which doesn't block the executing thread. Until then
     * return failures inside synctask if they use this.*/
    if (synctask_get())
        return -ENOTSUP;

    if (max_jobs == 0)
        return -EINVAL;

    /*Code becomes simpler this way. cond_wait just on qlength.
     * Little bit of cheating*/
    if (max_qlen == 0)
        max_qlen = 1;

    ret = syncop_dirfd(subvol, loc, &fd, pid);
    if (ret)
        goto out;

    INIT_LIST_HEAD(&entries.list);
    INIT_LIST_HEAD(&q.list);
    ret = pthread_mutex_init(&mut, NULL);
    if (ret)
        goto out;
    mut_init = _gf_true;

    ret = pthread_cond_init(&cond, NULL);
    if (ret)
        goto out;
    cond_init = _gf_true;

    while ((ret = syncop_readdir(subvol, fd, 131072, offset, &entries, xdata,
                                 NULL))) {
        if (ret < 0)
            break;

        if (ret > 0) {
            /* If the entries are only '.', and '..' then ret
             * value will be non-zero. so set it to zero here. */
            ret = 0;
        }

        last = list_last_entry(&entries.list, typeof(*last), list);
        offset = last->d_off;

        list_for_each_entry_safe(entry, tmp, &entries.list, list)
        {
            list_del_init(&entry->list);
            if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..")) {
                gf_dirent_entry_free(entry);
                continue;
            }

            if (entry->d_stat.ia_type == IA_IFDIR) {
                ret = fn(subvol, entry, loc, data);
                gf_dirent_entry_free(entry);
                if (ret)
                    goto out;
                continue;
            }

            if (retval) /*Any jobs failed?*/
                goto out;

            pthread_mutex_lock(&mut);
            {
                while (qlen == max_qlen)
                    pthread_cond_wait(&cond, &mut);
                if (max_jobs == jobs_running) {
                    list_add_tail(&entry->list, &q.list);
                    qlen++;
                    entry = NULL;
                } else {
                    jobs_running++;
                }
            }
            pthread_mutex_unlock(&mut);

            if (!entry)
                continue;

            ret = _run_dir_scan_task(frame, subvol, loc, &q, entry, &retval,
                                     &mut, &cond, &jobs_running, &qlen, fn,
                                     data);
            if (ret)
                goto out;
        }
    }

out:
    if (fd)
        fd_unref(fd);
    if (mut_init && cond_init) {
        pthread_mutex_lock(&mut);
        {
            while (jobs_running)
                pthread_cond_wait(&cond, &mut);
        }
        pthread_mutex_unlock(&mut);
        gf_dirent_free(&q);
        gf_dirent_free(&entries);
    }

    if (mut_init)
        pthread_mutex_destroy(&mut);
    if (cond_init)
        pthread_cond_destroy(&cond);
    return ret | retval;
}

int
syncop_dir_scan(xlator_t *subvol, loc_t *loc, int pid, void *data,
                int (*fn)(xlator_t *subvol, gf_dirent_t *entry, loc_t *parent,
                          void *data))
{
    fd_t *fd = NULL;
    uint64_t offset = 0;
    gf_dirent_t *entry = NULL;
    int ret = 0;
    gf_dirent_t entries;

    ret = syncop_dirfd(subvol, loc, &fd, pid);
    if (ret)
        goto out;

    INIT_LIST_HEAD(&entries.list);

    while ((ret = syncop_readdir(subvol, fd, 131072, offset, &entries, NULL,
                                 NULL))) {
        if (ret < 0)
            break;

        if (ret > 0) {
            /* If the entries are only '.', and '..' then ret
             * value will be non-zero. so set it to zero here. */
            ret = 0;
        }

        list_for_each_entry(entry, &entries.list, list)
        {
            offset = entry->d_off;

            if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
                continue;

            ret = fn(subvol, entry, loc, data);
            if (ret)
                break;
        }
        gf_dirent_free(&entries);
        if (ret)
            break;
    }

out:
    if (fd)
        fd_unref(fd);
    return ret;
}

int
syncop_is_subvol_local(xlator_t *this, loc_t *loc, gf_boolean_t *is_local)
{
    char *pathinfo = NULL;
    dict_t *xattr = NULL;
    int ret = 0;

    if (!this || !this->type || !is_local)
        return -EINVAL;

    if (strcmp(this->type, "protocol/client") != 0)
        return -EINVAL;

    *is_local = _gf_false;

    ret = syncop_getxattr(this, loc, &xattr, GF_XATTR_PATHINFO_KEY, NULL, NULL);
    if (ret < 0) {
        ret = -1;
        goto out;
    }

    if (!xattr) {
        ret = -EINVAL;
        goto out;
    }

    ret = dict_get_str(xattr, GF_XATTR_PATHINFO_KEY, &pathinfo);
    if (ret)
        goto out;

    ret = glusterfs_is_local_pathinfo(pathinfo, is_local);

    gf_msg_debug(this->name, 0, "subvol %s is %slocal", this->name,
                 *is_local ? "" : "not ");

out:
    if (xattr)
        dict_unref(xattr);

    return ret;
}

/**
 * For hard resove, it it telling posix to make use of the
 * gfid2path extended attribute stored on disk. Otherwise
 * posix xlator (with GFID_TO_PATH_KEY as the key) will just
 * do a in memory inode_path to get the path. Depending upon
 * the consumer of this function, they can choose how they want
 * to proceed. If doing a xattr operation sounds costly, then
 * use GFID_TO_PATH_KEY as the key for getxattr.
 **/

int
syncop_gfid_to_path_hard(inode_table_t *itable, xlator_t *subvol, uuid_t gfid,
                         inode_t *inode, char **path_p,
                         gf_boolean_t hard_resolve)
{
    int ret = 0;
    char *path = NULL;
    loc_t loc = {
        0,
    };
    dict_t *xattr = NULL;

    gf_uuid_copy(loc.gfid, gfid);

    if (!inode)
        loc.inode = inode_new(itable);
    else
        loc.inode = inode_ref(inode);

    if (!hard_resolve)
        ret = syncop_getxattr(subvol, &loc, &xattr, GFID_TO_PATH_KEY, NULL,
                              NULL);
    else
        ret = syncop_getxattr(subvol, &loc, &xattr, GFID2PATH_VIRT_XATTR_KEY,
                              NULL, NULL);

    if (ret < 0)
        goto out;

    /*
     * posix will do dict_set_dynstr for GFID_TO_PATH_KEY i.e.
     * for in memory search for the path. And for on disk xattr
     * fetching of the path for the key GFID2PATH_VIRT_XATTR_KEY
     * it uses dict_set_dynptr. So, for GFID2PATH_VIRT_XATTR_KEY
     * use dict_get_ptr to avoid dict complaining about type
     * mismatch (i.e. str vs ptr)
     */
    if (!hard_resolve)
        ret = dict_get_str(xattr, GFID_TO_PATH_KEY, &path);
    else
        ret = dict_get_ptr(xattr, GFID2PATH_VIRT_XATTR_KEY, (void **)&path);

    if (ret || !path) {
        ret = -EINVAL;
        goto out;
    }

    if (path_p) {
        *path_p = gf_strdup(path);
        if (!*path_p) {
            ret = -ENOMEM;
            goto out;
        }
    }

    ret = 0;

out:
    if (xattr)
        dict_unref(xattr);
    loc_wipe(&loc);

    return ret;
}

int
syncop_gfid_to_path(inode_table_t *itable, xlator_t *subvol, uuid_t gfid,
                    char **path_p)
{
    return syncop_gfid_to_path_hard(itable, subvol, gfid, NULL, path_p,
                                    _gf_false);
}

int
syncop_inode_find(xlator_t *this, xlator_t *subvol, uuid_t gfid,
                  inode_t **inode, dict_t *xdata, dict_t **rsp_dict)
{
    int ret = 0;
    loc_t loc = {
        0,
    };
    struct iatt iatt = {
        0,
    };
    *inode = NULL;

    *inode = inode_find(this->itable, gfid);
    if (*inode)
        goto out;

    loc.inode = inode_new(this->itable);
    if (!loc.inode) {
        ret = -ENOMEM;
        goto out;
    }
    gf_uuid_copy(loc.gfid, gfid);

    ret = syncop_lookup(subvol, &loc, &iatt, NULL, xdata, rsp_dict);
    if (ret < 0)
        goto out;

    *inode = inode_link(loc.inode, NULL, NULL, &iatt);
    if (!*inode) {
        ret = -ENOMEM;
        goto out;
    }
out:
    loc_wipe(&loc);
    return ret;
}