/*
  Copyright (c) 2008-2012 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 "common-utils.h"
#include "xlator.h"
#include "client.h"
#include "lkowner.h"

static void
__insert_and_merge (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock);

static void
__dump_client_lock (client_posix_lock_t *lock)
{
        xlator_t *this = NULL;

        this = THIS;

        gf_log (this->name, GF_LOG_INFO,
                "{fd=%p}"
                "{%s lk-owner:%s %"PRId64" - %"PRId64"}"
                "{start=%"PRId64" end=%"PRId64"}",
                lock->fd,
                lock->fl_type == F_WRLCK ? "Write-Lock" : "Read-Lock",
                lkowner_utoa (&lock->owner),
                lock->user_flock.l_start,
                lock->user_flock.l_len,
                lock->fl_start,
                lock->fl_end);
}

static int
dump_client_locks_fd (clnt_fd_ctx_t *fdctx)
{
        client_posix_lock_t *lock = NULL;
        int count = 0;

        pthread_mutex_lock (&fdctx->mutex);
        {
                list_for_each_entry (lock, &fdctx->lock_list, list) {
                        __dump_client_lock (lock);
                        count++;
                }
        }
        pthread_mutex_unlock (&fdctx->mutex);

        return count;

}

int
dump_client_locks (inode_t *inode)
{
        fd_t             *fd    = NULL;
        clnt_conf_t    *conf  = NULL;
        xlator_t         *this  = NULL;
        clnt_fd_ctx_t  *fdctx = NULL;

        int total_count = 0;
        int locks_fd_count   = 0;

        this = THIS;
        conf = this->private;

        LOCK (&inode->lock);
        {
                list_for_each_entry (fd, &inode->fd_list, inode_list) {
                        locks_fd_count = 0;

                        pthread_mutex_lock (&conf->lock);
                        {
                                fdctx = this_fd_get_ctx (fd, this);
                        }
                        pthread_mutex_unlock (&conf->lock);

                        if (fdctx)
                                locks_fd_count = dump_client_locks_fd (fdctx);

                        total_count += locks_fd_count;
                }

        }
        UNLOCK (&inode->lock);

        return total_count;

}

static off_t
__get_lock_length (off_t start, off_t end)
{
        if (end == LLONG_MAX)
                return 0;
        else
                return (end - start + 1);
}

/* Add two locks */
static client_posix_lock_t *
add_locks (client_posix_lock_t *l1, client_posix_lock_t *l2)
{
	client_posix_lock_t *sum = NULL;

	sum = GF_CALLOC (1, sizeof (*sum), gf_client_mt_clnt_lock_t);
	if (!sum)
		return NULL;

	sum->fl_start = min (l1->fl_start, l2->fl_start);
	sum->fl_end   = max (l1->fl_end, l2->fl_end);

        sum->user_flock.l_start = sum->fl_start;
        sum->user_flock.l_len   = __get_lock_length (sum->fl_start,
                                                     sum->fl_end);

	return sum;
}


/* Return true if the locks overlap, false otherwise */
static int
locks_overlap (client_posix_lock_t *l1, client_posix_lock_t *l2)
{
	/*
	   Note:
	   FUSE always gives us absolute offsets, so no need to worry
	   about SEEK_CUR or SEEK_END
	*/

	return ((l1->fl_end >= l2->fl_start) &&
		(l2->fl_end >= l1->fl_start));
}

static void
__delete_client_lock (client_posix_lock_t *lock)
{
	list_del_init (&lock->list);
}

/* Destroy a posix_lock */
static void
__destroy_client_lock (client_posix_lock_t *lock)
{
	GF_FREE (lock);
}

/* Subtract two locks */
struct _values {
	client_posix_lock_t *locks[3];
};

/* {big} must always be contained inside {small} */
static struct _values
subtract_locks (client_posix_lock_t *big, client_posix_lock_t *small)
{
	struct _values v = { .locks = {0, 0, 0} };

	if ((big->fl_start == small->fl_start) &&
	    (big->fl_end   == small->fl_end)) {
		/* both edges coincide with big */
		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t );
		GF_ASSERT (v.locks[0]);
		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
		v.locks[0]->fl_type = small->fl_type;
	}
	else if ((small->fl_start > big->fl_start) &&
		 (small->fl_end   < big->fl_end)) {
		/* both edges lie inside big */
		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[0]);
		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                     gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[1]);
		v.locks[2] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[2]);

		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
		v.locks[0]->fl_end = small->fl_start - 1;
                v.locks[0]->user_flock.l_len = __get_lock_length (v.locks[0]->fl_start,
                                                                  v.locks[0]->fl_end);

		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
		memcpy (v.locks[2], big, sizeof (client_posix_lock_t));
		v.locks[2]->fl_start = small->fl_end + 1;
                v.locks[2]->user_flock.l_start = small->fl_end + 1;
	}
	/* one edge coincides with big */
	else if (small->fl_start == big->fl_start) {
		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[0]);
		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[1]);

		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
		v.locks[0]->fl_start = small->fl_end + 1;
                v.locks[0]->user_flock.l_start = small->fl_end + 1;

		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
	}
	else if (small->fl_end   == big->fl_end) {
		v.locks[0] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[0]);
		v.locks[1] = GF_CALLOC (1, sizeof (client_posix_lock_t),
                                        gf_client_mt_clnt_lock_t);
		GF_ASSERT (v.locks[1]);

		memcpy (v.locks[0], big, sizeof (client_posix_lock_t));
		v.locks[0]->fl_end = small->fl_start - 1;
                v.locks[0]->user_flock.l_len = __get_lock_length (v.locks[0]->fl_start,
                                                                  v.locks[0]->fl_end);

		memcpy (v.locks[1], small, sizeof (client_posix_lock_t));
	}
        else {
                /* LOG-TODO : decide what more info is required here*/
                gf_log ("client-protocol", GF_LOG_CRITICAL,
                        "Unexpected case in subtract_locks. Please send "
                        "a bug report to gluster-devel@nongnu.org");
        }

        return v;
}

static void
__delete_unlck_locks (clnt_fd_ctx_t *fdctx)
{
	client_posix_lock_t *l = NULL;
	client_posix_lock_t *tmp = NULL;

	list_for_each_entry_safe (l, tmp, &fdctx->lock_list, list) {
		if (l->fl_type == F_UNLCK) {
			__delete_client_lock (l);
			__destroy_client_lock (l);
		}
	}
}

static void
__insert_lock (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
{
	list_add_tail (&lock->list, &fdctx->lock_list);

	return;
}

static void
__insert_and_merge (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
{
        client_posix_lock_t  *conf = NULL;
        client_posix_lock_t  *t = NULL;
        client_posix_lock_t  *sum = NULL;
        int            i = 0;
        struct _values v = { .locks = {0, 0, 0} };

        list_for_each_entry_safe (conf, t, &fdctx->lock_list, list) {
                if (!locks_overlap (conf, lock))
                        continue;

                if (is_same_lkowner (&conf->owner, &lock->owner)) {
                        if (conf->fl_type == lock->fl_type) {
                                sum = add_locks (lock, conf);

                                sum->fd = lock->fd;

                                __delete_client_lock (conf);
                                __destroy_client_lock (conf);

                                __destroy_client_lock (lock);
                                __insert_and_merge (fdctx, sum);

                                return;
                        } else {
                                sum = add_locks (lock, conf);

                                sum->fd = conf->fd;
                                sum->owner = conf->owner;

                                v = subtract_locks (sum, lock);

                                __delete_client_lock (conf);
                                __destroy_client_lock (conf);

                                __delete_client_lock (lock);
                                __destroy_client_lock (lock);

                                __destroy_client_lock (sum);

                                for (i = 0; i < 3; i++) {
                                        if (!v.locks[i])
                                                continue;

                                        INIT_LIST_HEAD (&v.locks[i]->list);
                                        __insert_and_merge (fdctx,
                                                            v.locks[i]);
                                }

                                __delete_unlck_locks (fdctx);
                                return;
                        }
                }

                if (lock->fl_type == F_UNLCK) {
                        continue;
                }

                if ((conf->fl_type == F_RDLCK) && (lock->fl_type == F_RDLCK)) {
                        __insert_lock (fdctx, lock);
                        return;
                }
        }

        /* no conflicts, so just insert */
        if (lock->fl_type != F_UNLCK) {
                __insert_lock (fdctx, lock);
        } else {
                __destroy_client_lock (lock);
        }
}

static void
client_setlk (clnt_fd_ctx_t *fdctx, client_posix_lock_t *lock)
{
        pthread_mutex_lock (&fdctx->mutex);
        {
                __insert_and_merge (fdctx, lock);
        }
        pthread_mutex_unlock (&fdctx->mutex);

        return;
}

static void
destroy_client_lock (client_posix_lock_t *lock)
{
        GF_FREE (lock);
}

int32_t
delete_granted_locks_owner (fd_t *fd, gf_lkowner_t *owner)
{
        clnt_fd_ctx_t       *fdctx = NULL;
        client_posix_lock_t *lock  = NULL;
        client_posix_lock_t *tmp   = NULL;
        xlator_t            *this  = NULL;

        struct list_head delete_list;
        int ret   = 0;
        int count = 0;

        INIT_LIST_HEAD (&delete_list);
        this = THIS;
        fdctx = this_fd_get_ctx (fd, this);
        if (!fdctx) {
                gf_log (this->name, GF_LOG_WARNING,
                        "fdctx not valid");
                ret = -1;
                goto out;
        }

        pthread_mutex_lock (&fdctx->mutex);
        {
                list_for_each_entry_safe (lock, tmp, &fdctx->lock_list, list) {
                        if (!is_same_lkowner (&lock->owner, owner)) {
                                list_del_init (&lock->list);
                                list_add_tail (&lock->list, &delete_list);
                                count++;
                        }
                }
        }
        pthread_mutex_unlock (&fdctx->mutex);

        list_for_each_entry_safe (lock, tmp, &delete_list, list) {
                list_del_init (&lock->list);
                destroy_client_lock (lock);
        }

        /* FIXME: Need to actually print the locks instead of count */
        gf_log (this->name, GF_LOG_TRACE,
                "Number of locks cleared=%d", count);

out:
        return ret;
}

int32_t
delete_granted_locks_fd (clnt_fd_ctx_t *fdctx)
{
        client_posix_lock_t *lock = NULL;
        client_posix_lock_t *tmp = NULL;
        xlator_t            *this = NULL;

        struct list_head delete_list;
        int ret   = 0;
        int count = 0;

        INIT_LIST_HEAD (&delete_list);
        this = THIS;

        pthread_mutex_lock (&fdctx->mutex);
        {
                list_splice_init (&fdctx->lock_list, &delete_list);
        }
        pthread_mutex_unlock (&fdctx->mutex);

        list_for_each_entry_safe (lock, tmp, &delete_list, list) {
                list_del_init (&lock->list);
                count++;
                destroy_client_lock (lock);
        }

        /* FIXME: Need to actually print the locks instead of count */
        gf_log (this->name, GF_LOG_TRACE,
                "Number of locks cleared=%d", count);

        return  ret;
}

int32_t
client_cmd_to_gf_cmd (int32_t cmd, int32_t *gf_cmd)
{
        int ret = 0;

        if (cmd == F_GETLK || cmd == F_GETLK64)
                *gf_cmd = GF_LK_GETLK;
        else if (cmd == F_SETLK || cmd == F_SETLK64)
                *gf_cmd = GF_LK_SETLK;
        else if (cmd == F_SETLKW || cmd == F_SETLKW64)
                *gf_cmd = GF_LK_SETLKW;
        else if (cmd == F_RESLK_LCK)
                *gf_cmd = GF_LK_RESLK_LCK;
        else if (cmd == F_RESLK_LCKW)
                *gf_cmd = GF_LK_RESLK_LCKW;
        else if (cmd == F_RESLK_UNLCK)
                *gf_cmd = GF_LK_RESLK_UNLCK;
        else if (cmd == F_GETLK_FD)
                *gf_cmd = GF_LK_GETLK_FD;
        else
                ret = -1;

        return ret;

}

static client_posix_lock_t *
new_client_lock (struct gf_flock *flock, gf_lkowner_t *owner,
                 int32_t cmd, fd_t *fd)
{
        client_posix_lock_t *new_lock = NULL;

        new_lock = GF_CALLOC (1, sizeof (*new_lock),
                              gf_client_mt_clnt_lock_t);
        if (!new_lock) {
                goto out;
        }

        INIT_LIST_HEAD (&new_lock->list);
        new_lock->fd = fd;
        memcpy (&new_lock->user_flock, flock, sizeof (struct gf_flock));

        new_lock->fl_type  = flock->l_type;
        new_lock->fl_start = flock->l_start;

	if (flock->l_len == 0)
		new_lock->fl_end = LLONG_MAX;
	else
		new_lock->fl_end = flock->l_start + flock->l_len - 1;

        new_lock->owner = *owner;

        new_lock->cmd = cmd; /* Not really useful */

out:
        return new_lock;
}

void
client_save_number_fds (clnt_conf_t *conf, int count)
{
        LOCK (&conf->rec_lock);
        {
                conf->reopen_fd_count = count;
        }
        UNLOCK (&conf->rec_lock);
}

int
client_add_lock_for_recovery (fd_t *fd, struct gf_flock *flock,
                              gf_lkowner_t *owner, int32_t cmd)
{
        clnt_fd_ctx_t       *fdctx = NULL;
        xlator_t            *this  = NULL;
        client_posix_lock_t *lock  = NULL;
        clnt_conf_t         *conf  = NULL;

        int ret = 0;

        this = THIS;
        conf = this->private;

        pthread_mutex_lock (&conf->lock);
        {
                fdctx = this_fd_get_ctx (fd, this);
        }
        pthread_mutex_unlock (&conf->lock);

        if (!fdctx) {
                gf_log (this->name, GF_LOG_WARNING,
                        "failed to get fd context. sending EBADFD");
                ret = -EBADFD;
                goto out;
        }

        lock = new_client_lock (flock, owner, cmd, fd);
        if (!lock) {
                ret = -ENOMEM;
                goto out;
        }

        client_setlk (fdctx, lock);

out:
        return ret;

}

int32_t
client_dump_locks (char *name, inode_t *inode,
                   dict_t *dict)
{
        int     ret = 0;
        dict_t *new_dict = NULL;
        char    dict_string[256];

        GF_ASSERT (dict);
        new_dict = dict;

        ret = dump_client_locks (inode);
        snprintf (dict_string, 256, "%d locks dumped in log file", ret);

        ret = dict_set_dynstr(new_dict, CLIENT_DUMP_LOCKS, dict_string);
        if (ret) {
                gf_log (THIS->name, GF_LOG_WARNING,
                        "could not set dict with %s", CLIENT_DUMP_LOCKS);
                goto out;
        }

out:

        return ret;
}

int32_t
is_client_dump_locks_cmd (char *name)
{
        int ret = 0;

        if (strcmp (name, CLIENT_DUMP_LOCKS) == 0)
                ret = 1;

        return ret;
}