/*
  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.
*/
#ifndef __BIT_ROT_STUB_H__
#define __BIT_ROT_STUB_H__

#include <glusterfs/glusterfs.h>
#include <glusterfs/logging.h>
#include <glusterfs/dict.h>
#include <glusterfs/xlator.h>
#include <glusterfs/defaults.h>
#include <glusterfs/call-stub.h>
#include "bit-rot-stub-mem-types.h"
#include <glusterfs/syscall.h>
#include <glusterfs/common-utils.h>
#include "bit-rot-common.h"
#include "bit-rot-stub-messages.h"
#include "glusterfs3-xdr.h"
#include <glusterfs/syncop.h>
#include <glusterfs/syncop-utils.h>

#define BAD_OBJECT_THREAD_STACK_SIZE ((size_t)(1024 * 1024))
#define BR_STUB_DUMP_STR_SIZE 65536

#define BR_PATH_MAX_EXTRA (PATH_MAX + 1024)
#define BR_PATH_MAX_PLUS (PATH_MAX + 2048)

/*
 * Oops. Spelling mistake. Correcting it
 */
#define OLD_BR_STUB_QUARANTINE_DIR GF_HIDDEN_PATH "/quanrantine"
#define BR_STUB_QUARANTINE_DIR GF_HIDDEN_PATH "/quarantine"

/* do not reference frame->local in cbk unless initialized.
 * Assigned 0x1 marks verisoning flag between call path and
 * cbk path.
 */
#define BR_STUB_VER_NOT_ACTIVE_THEN_GOTO(frame, priv, label)                   \
    do {                                                                       \
        if (priv->do_versioning)                                               \
            frame->local = (void *)0x1;                                        \
        else                                                                   \
            goto label;                                                        \
    } while (0)

#define BR_STUB_VER_COND_GOTO(priv, cond, label)                               \
    do {                                                                       \
        if (!priv->do_versioning || cond)                                      \
            goto label;                                                        \
    } while (0)

#define BR_STUB_VER_ENABLED_IN_CALLPATH(frame, flag)                           \
    do {                                                                       \
        if (frame->local)                                                      \
            flag = _gf_true;                                                   \
        if (frame->local == (void *)0x1)                                       \
            frame->local = NULL;                                               \
    } while (0)

#define BR_STUB_RESET_LOCAL_NULL(frame)                                        \
    do {                                                                       \
        if (frame->local == (void *)0x1)                                       \
            frame->local = NULL;                                               \
    } while (0)

typedef int(br_stub_version_cbk)(call_frame_t *, void *, xlator_t *, int32_t,
                                 int32_t, dict_t *);

typedef struct br_stub_inode_ctx {
    int need_writeback;           /* does the inode need
                                        a writeback to disk? */
    unsigned long currentversion; /* ongoing version */

    int info_sign;
    struct list_head fd_list; /* list of open fds or fds participating in
                                 write operations */
    gf_boolean_t bad_object;
} br_stub_inode_ctx_t;

typedef struct br_stub_fd {
    fd_t *fd;
    struct list_head list;
    struct bad_object_dir {
        DIR *dir;
        off_t dir_eof;
    } bad_object;
} br_stub_fd_t;

#define I_DIRTY (1 << 0) /* inode needs writeback */
#define I_MODIFIED (1 << 1)
#define WRITEBACK_DURABLE 1 /* writeback is durable */

/**
 * This could just have been a plain struct without unions and all,
 * but we may need additional things in the future.
 */
typedef struct br_stub_local {
    call_stub_t *fopstub; /* stub for original fop */

    int versioningtype; /* not much used atm */

    union {
        struct br_stub_ctx {
            fd_t *fd;
            uuid_t gfid;
            inode_t *inode;
            unsigned long version;
        } context;
    } u;
} br_stub_local_t;

#define BR_STUB_NO_VERSIONING (1 << 0)
#define BR_STUB_INCREMENTAL_VERSIONING (1 << 1)

typedef struct br_stub_private {
    gf_boolean_t do_versioning;

    uint32_t boot[2];
    char export[PATH_MAX];

    pthread_mutex_t lock;
    pthread_cond_t cond;

    struct list_head squeue; /* ordered signing queue */
    pthread_t signth;
    struct bad_objects_container {
        pthread_t thread;
        pthread_mutex_t bad_lock;
        pthread_cond_t bad_cond;
        struct list_head bad_queue;
    } container;
    struct mem_pool *local_pool;

    char stub_basepath[BR_PATH_MAX_EXTRA];

    uuid_t bad_object_dir_gfid;
} br_stub_private_t;

br_stub_fd_t *
br_stub_fd_new(void);

int
__br_stub_fd_ctx_set(xlator_t *this, fd_t *fd, br_stub_fd_t *br_stub_fd);

br_stub_fd_t *
__br_stub_fd_ctx_get(xlator_t *this, fd_t *fd);

br_stub_fd_t *
br_stub_fd_ctx_get(xlator_t *this, fd_t *fd);

int32_t
br_stub_fd_ctx_set(xlator_t *this, fd_t *fd, br_stub_fd_t *br_stub_fd);

static inline gf_boolean_t
__br_stub_is_bad_object(br_stub_inode_ctx_t *ctx)
{
    return ctx->bad_object;
}

static inline void
__br_stub_mark_object_bad(br_stub_inode_ctx_t *ctx)
{
    ctx->bad_object = _gf_true;
}

/* inode writeback helpers */
static inline void
__br_stub_mark_inode_dirty(br_stub_inode_ctx_t *ctx)
{
    ctx->need_writeback |= I_DIRTY;
}

static inline void
__br_stub_mark_inode_synced(br_stub_inode_ctx_t *ctx)
{
    ctx->need_writeback &= ~I_DIRTY;
}

static inline int
__br_stub_is_inode_dirty(br_stub_inode_ctx_t *ctx)
{
    return (ctx->need_writeback & I_DIRTY);
}

/* inode mofification markers */
static inline void
__br_stub_set_inode_modified(br_stub_inode_ctx_t *ctx)
{
    ctx->need_writeback |= I_MODIFIED;
}

static inline void
__br_stub_unset_inode_modified(br_stub_inode_ctx_t *ctx)
{
    ctx->need_writeback &= ~I_MODIFIED;
}

static inline int
__br_stub_is_inode_modified(br_stub_inode_ctx_t *ctx)
{
    return (ctx->need_writeback & I_MODIFIED);
}

static inline int
br_stub_require_release_call(xlator_t *this, fd_t *fd, br_stub_fd_t **fd_ctx)
{
    int32_t ret = 0;
    br_stub_fd_t *br_stub_fd = NULL;

    br_stub_fd = br_stub_fd_new();
    if (!br_stub_fd)
        return -1;

    br_stub_fd->fd = fd;
    INIT_LIST_HEAD(&br_stub_fd->list);

    ret = br_stub_fd_ctx_set(this, fd, br_stub_fd);
    if (ret)
        gf_msg(this->name, GF_LOG_WARNING, 0, BRS_MSG_SET_CONTEXT_FAILED,
               "could not set fd context (for release callback");
    else
        *fd_ctx = br_stub_fd;

    return ret;
}

/* get/set inode context helpers */

static inline int
__br_stub_get_inode_ctx(xlator_t *this, inode_t *inode, uint64_t *ctx)
{
    return __inode_ctx_get(inode, this, ctx);
}

static inline int
br_stub_get_inode_ctx(xlator_t *this, inode_t *inode, uint64_t *ctx)
{
    int ret = -1;

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

    return ret;
}

static inline int
br_stub_set_inode_ctx(xlator_t *this, inode_t *inode, br_stub_inode_ctx_t *ctx)
{
    uint64_t ctx_addr = (uint64_t)(uintptr_t)ctx;
    return inode_ctx_set(inode, this, &ctx_addr);
}

/* version get/set helpers */

static inline unsigned long
__br_stub_writeback_version(br_stub_inode_ctx_t *ctx)
{
    return (ctx->currentversion + 1);
}

static inline void
__br_stub_set_ongoing_version(br_stub_inode_ctx_t *ctx, unsigned long version)
{
    if (ctx->currentversion < version)
        ctx->currentversion = version;
    else
        gf_msg("bit-rot-stub", GF_LOG_WARNING, 0, BRS_MSG_CHANGE_VERSION_FAILED,
               "current version: %lu"
               "new version: %lu",
               ctx->currentversion, version);
}

static inline int
__br_stub_can_trigger_release(inode_t *inode, br_stub_inode_ctx_t *ctx,
                              unsigned long *version)
{
    /**
     * If the inode is modified, then it has to be dirty. An inode is
     * marked dirty once version is increased. Its marked as modified
     * when the modification call (write/truncate) which triggered
     * the versioning is successful.
     */
    if (__br_stub_is_inode_modified(ctx) && list_empty(&ctx->fd_list) &&
        (ctx->info_sign != BR_SIGN_REOPEN_WAIT)) {
        GF_ASSERT(__br_stub_is_inode_dirty(ctx) == 0);

        if (version)
            *version = htonl(ctx->currentversion);
        return 1;
    }

    return 0;
}

static inline int32_t
br_stub_get_ongoing_version(xlator_t *this, inode_t *inode,
                            unsigned long *version)
{
    int32_t ret = 0;
    uint64_t ctx_addr = 0;
    br_stub_inode_ctx_t *ctx = NULL;

    LOCK(&inode->lock);
    {
        ret = __inode_ctx_get(inode, this, &ctx_addr);
        if (ret < 0)
            goto unblock;
        ctx = (br_stub_inode_ctx_t *)(long)ctx_addr;
        *version = ctx->currentversion;
    }
unblock:
    UNLOCK(&inode->lock);

    return ret;
}

/**
 * fetch the current version from inode and return the context.
 * inode->lock should be held before invoking this as context
 * *needs* to be valid in the caller.
 */
static inline br_stub_inode_ctx_t *
__br_stub_get_ongoing_version_ctx(xlator_t *this, inode_t *inode,
                                  unsigned long *version)
{
    int32_t ret = 0;
    uint64_t ctx_addr = 0;
    br_stub_inode_ctx_t *ctx = NULL;

    ret = __inode_ctx_get(inode, this, &ctx_addr);
    if (ret < 0)
        return NULL;
    ctx = (br_stub_inode_ctx_t *)(long)ctx_addr;
    if (version)
        *version = ctx->currentversion;

    return ctx;
}

/* filter for xattr fetch */
static inline int
br_stub_is_internal_xattr(const char *name)
{
    if (name && ((strncmp(name, BITROT_CURRENT_VERSION_KEY,
                          SLEN(BITROT_CURRENT_VERSION_KEY)) == 0) ||
                 (strncmp(name, BITROT_SIGNING_VERSION_KEY,
                          SLEN(BITROT_SIGNING_VERSION_KEY)) == 0)))
        return 1;
    return 0;
}

static inline void
br_stub_remove_vxattrs(dict_t *xattr, gf_boolean_t remove_bad_marker)
{
    if (xattr) {
        /*
         * When a file is corrupted, bad-object should be
         * set in the dict. But, other info such as version,
         * signature etc should not be set. Hence the flag
         * remove_bad_marker. The consumer should know whether
         * to send the bad-object info in the dict or not.
         */
        if (remove_bad_marker)
            dict_del(xattr, BITROT_OBJECT_BAD_KEY);
        dict_del(xattr, BITROT_CURRENT_VERSION_KEY);
        dict_del(xattr, BITROT_SIGNING_VERSION_KEY);
        dict_del(xattr, BITROT_SIGNING_XATTR_SIZE_KEY);
    }
}

/**
 * This function returns the below values for different situations
 * 0  => as per the inode context object is not bad
 * -1 => Failed to get the inode context itself
 * -2 => As per the inode context object is bad
 * Both -ve values means the fop which called this function is failed
 * and error is returned upwards.
 * In future if needed or more errors have to be handled, then those
 * errors can be made into enums.
 */
static inline int
br_stub_is_bad_object(xlator_t *this, inode_t *inode)
{
    int bad_object = 0;
    gf_boolean_t tmp = _gf_false;
    uint64_t ctx_addr = 0;
    br_stub_inode_ctx_t *ctx = NULL;
    int32_t ret = -1;

    ret = br_stub_get_inode_ctx(this, inode, &ctx_addr);
    if (ret) {
        gf_msg(this->name, GF_LOG_ERROR, 0, BRS_MSG_GET_INODE_CONTEXT_FAILED,
               "failed to get the inode context for the inode %s",
               uuid_utoa(inode->gfid));
        bad_object = -1;
        goto out;
    }

    ctx = (br_stub_inode_ctx_t *)(long)ctx_addr;

    LOCK(&inode->lock);
    {
        tmp = __br_stub_is_bad_object(ctx);
        if (tmp)
            bad_object = -2;
    }
    UNLOCK(&inode->lock);

out:
    return bad_object;
}

static inline int32_t
br_stub_mark_object_bad(xlator_t *this, inode_t *inode)
{
    int32_t ret = -1;
    uint64_t ctx_addr = 0;
    br_stub_inode_ctx_t *ctx = NULL;

    ret = br_stub_get_inode_ctx(this, inode, &ctx_addr);
    if (ret) {
        gf_msg(this->name, GF_LOG_ERROR, 0, BRS_MSG_GET_INODE_CONTEXT_FAILED,
               "failed to get the "
               "inode context for the inode %s",
               uuid_utoa(inode->gfid));
        goto out;
    }

    ctx = (br_stub_inode_ctx_t *)(long)ctx_addr;

    LOCK(&inode->lock);
    {
        __br_stub_mark_object_bad(ctx);
    }
    UNLOCK(&inode->lock);

out:
    return ret;
}

/**
 * There is a possibility that dict_set might fail. The o/p of dict_set is
 * given to the caller and the caller has to decide what to do.
 */
static inline int32_t
br_stub_mark_xdata_bad_object(xlator_t *this, inode_t *inode, dict_t *xdata)
{
    int32_t ret = 0;

    if (br_stub_is_bad_object(this, inode) == -2)
        ret = dict_set_int32(xdata, GLUSTERFS_BAD_INODE, 1);

    return ret;
}

int32_t
br_stub_add_fd_to_inode(xlator_t *this, fd_t *fd, br_stub_inode_ctx_t *ctx);

br_sign_state_t
__br_stub_inode_sign_state(br_stub_inode_ctx_t *ctx, glusterfs_fop_t fop,
                           fd_t *fd);

int
br_stub_dir_create(xlator_t *this, br_stub_private_t *priv);

int
br_stub_add(xlator_t *this, uuid_t gfid);

int32_t
br_stub_create_stub_gfid(xlator_t *this, char *stub_gfid_path, uuid_t gfid);

int
br_stub_dir_create(xlator_t *this, br_stub_private_t *priv);

call_stub_t *
__br_stub_dequeue(struct list_head *callstubs);

void
__br_stub_enqueue(struct list_head *callstubs, call_stub_t *stub);

void
br_stub_worker_enqueue(xlator_t *this, call_stub_t *stub);

void *
br_stub_worker(void *data);

int32_t
br_stub_lookup_wrapper(call_frame_t *frame, xlator_t *this, loc_t *loc,
                       dict_t *xattr_req);

int32_t
br_stub_readdir_wrapper(call_frame_t *frame, xlator_t *this, fd_t *fd,
                        size_t size, off_t off, dict_t *xdata);

int
br_stub_del(xlator_t *this, uuid_t gfid);

int
br_stub_bad_objects_path(xlator_t *this, fd_t *fd, gf_dirent_t *entries,
                         dict_t **dict);

void
br_stub_entry_xattr_fill(xlator_t *this, char *hpath, gf_dirent_t *entry,
                         dict_t *dict);

int
br_stub_get_path_of_gfid(xlator_t *this, inode_t *parent, inode_t *inode,
                         uuid_t gfid, char **path);

#endif /* __BIT_ROT_STUB_H__ */