/*
 * Ext4 orphan inode handling
 */
#include <linux/fs.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>

#include "ext4.h"
#include "ext4_jbd2.h"

static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
{
        int i, j, start;
        struct ext4_orphan_info *oi = &EXT4_SB(inode->i_sb)->s_orphan_info;
        int ret = 0;
        bool found = false;
        __le32 *bdata;
        int inodes_per_ob = ext4_inodes_per_orphan_block(inode->i_sb);
        int looped = 0;

        /*
         * Find block with free orphan entry. Use CPU number for a naive hash
         * for a search start in the orphan file
         */
        start = raw_smp_processor_id()*13 % oi->of_blocks;
        i = start;
        do {
                if (atomic_dec_if_positive(&oi->of_binfo[i].ob_free_entries)
                    >= 0) {
                        found = true;
                        break;
                }
                if (++i >= oi->of_blocks)
                        i = 0;
        } while (i != start);

        if (!found) {
                /*
                 * For now we don't grow or shrink orphan file. We just use
                 * whatever was allocated at mke2fs time. The additional
                 * credits we would have to reserve for each orphan inode
                 * operation just don't seem worth it.
                 */
                return -ENOSPC;
        }

        ret = ext4_journal_get_write_access(handle, inode->i_sb,
                                oi->of_binfo[i].ob_bh, EXT4_JTR_ORPHAN_FILE);
        if (ret) {
                atomic_inc(&oi->of_binfo[i].ob_free_entries);
                return ret;
        }

        bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
        /* Find empty slot in a block */
        j = 0;
        do {
                if (looped) {
                        /*
                         * Did we walk through the block several times without
                         * finding free entry? It is theoretically possible
                         * if entries get constantly allocated and freed or
                         * if the block is corrupted. Avoid indefinite looping
                         * and bail. We'll use orphan list instead.
                         */
                        if (looped > 3) {
                                atomic_inc(&oi->of_binfo[i].ob_free_entries);
                                return -ENOSPC;
                        }
                        cond_resched();
                }
                while (bdata[j]) {
                        if (++j >= inodes_per_ob) {
                                j = 0;
                                looped++;
                        }
                }
        } while (cmpxchg(&bdata[j], (__le32)0, cpu_to_le32(inode->i_ino)) !=
                 (__le32)0);

        EXT4_I(inode)->i_orphan_idx = i * inodes_per_ob + j;
        ext4_set_inode_state(inode, EXT4_STATE_ORPHAN_FILE);

        return ext4_handle_dirty_metadata(handle, NULL, oi->of_binfo[i].ob_bh);
}

/*
 * ext4_orphan_add() links an unlinked or truncated inode into a list of
 * such inodes, starting at the superblock, in case we crash before the
 * file is closed/deleted, or in case the inode truncate spans multiple
 * transactions and the last transaction is not recovered after a crash.
 *
 * At filesystem recovery time, we walk this list deleting unlinked
 * inodes and truncating linked inodes in ext4_orphan_cleanup().
 *
 * Orphan list manipulation functions must be called under i_mutex unless
 * we are just creating the inode or deleting it.
 */
int ext4_orphan_add(handle_t *handle, struct inode *inode)
{
        struct super_block *sb = inode->i_sb;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_iloc iloc;
        int err = 0, rc;
        bool dirty = false;

        if (!sbi->s_journal || is_bad_inode(inode))
                return 0;

        WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
                     !inode_is_locked(inode));
        /*
         * Inode orphaned in orphan file or in orphan list?
         */
        if (ext4_test_inode_state(inode, EXT4_STATE_ORPHAN_FILE) ||
            !list_empty(&EXT4_I(inode)->i_orphan))
                return 0;

        /*
         * Orphan handling is only valid for files with data blocks
         * being truncated, or files being unlinked. Note that we either
         * hold i_mutex, or the inode can not be referenced from outside,
         * so i_nlink should not be bumped due to race
         */
        ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
                  S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);

        if (sbi->s_orphan_info.of_blocks) {
                err = ext4_orphan_file_add(handle, inode);
                /*
                 * Fallback to normal orphan list of orphan file is
                 * out of space
                 */
                if (err != -ENOSPC)
                        return err;
        }

        BUFFER_TRACE(sbi->s_sbh, "get_write_access");
        err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
                                            EXT4_JTR_NONE);
        if (err)
                goto out;

        err = ext4_reserve_inode_write(handle, inode, &iloc);
        if (err)
                goto out;

        mutex_lock(&sbi->s_orphan_lock);
        /*
         * Due to previous errors inode may be already a part of on-disk
         * orphan list. If so skip on-disk list modification.
         */
        if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
            (le32_to_cpu(sbi->s_es->s_inodes_count))) {
                /* Insert this inode at the head of the on-disk orphan list */
                NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
                lock_buffer(sbi->s_sbh);
                sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
                ext4_superblock_csum_set(sb);
                unlock_buffer(sbi->s_sbh);
                dirty = true;
        }
        list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
        mutex_unlock(&sbi->s_orphan_lock);

        if (dirty) {
                err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
                rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
                if (!err)
                        err = rc;
                if (err) {
                        /*
                         * We have to remove inode from in-memory list if
                         * addition to on disk orphan list failed. Stray orphan
                         * list entries can cause panics at unmount time.
                         */
                        mutex_lock(&sbi->s_orphan_lock);
                        list_del_init(&EXT4_I(inode)->i_orphan);
                        mutex_unlock(&sbi->s_orphan_lock);
                }
        } else
                brelse(iloc.bh);

        jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
        jbd_debug(4, "orphan inode %lu will point to %d\n",
                        inode->i_ino, NEXT_ORPHAN(inode));
out:
        ext4_std_error(sb, err);
        return err;
}

static int ext4_orphan_file_del(handle_t *handle, struct inode *inode)
{
        struct ext4_orphan_info *oi = &EXT4_SB(inode->i_sb)->s_orphan_info;
        __le32 *bdata;
        int blk, off;
        int inodes_per_ob = ext4_inodes_per_orphan_block(inode->i_sb);
        int ret = 0;

        if (!handle)
                goto out;
        blk = EXT4_I(inode)->i_orphan_idx / inodes_per_ob;
        off = EXT4_I(inode)->i_orphan_idx % inodes_per_ob;
        if (WARN_ON_ONCE(blk >= oi->of_blocks))
                goto out;

        ret = ext4_journal_get_write_access(handle, inode->i_sb,
                                oi->of_binfo[blk].ob_bh, EXT4_JTR_ORPHAN_FILE);
        if (ret)
                goto out;

        bdata = (__le32 *)(oi->of_binfo[blk].ob_bh->b_data);
        bdata[off] = 0;
        atomic_inc(&oi->of_binfo[blk].ob_free_entries);
        ret = ext4_handle_dirty_metadata(handle, NULL, oi->of_binfo[blk].ob_bh);
out:
        ext4_clear_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
        INIT_LIST_HEAD(&EXT4_I(inode)->i_orphan);

        return ret;
}

/*
 * ext4_orphan_del() removes an unlinked or truncated inode from the list
 * of such inodes stored on disk, because it is finally being cleaned up.
 */
int ext4_orphan_del(handle_t *handle, struct inode *inode)
{
        struct list_head *prev;
        struct ext4_inode_info *ei = EXT4_I(inode);
        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
        __u32 ino_next;
        struct ext4_iloc iloc;
        int err = 0;

        if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
                return 0;

        WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
                     !inode_is_locked(inode));
        if (ext4_test_inode_state(inode, EXT4_STATE_ORPHAN_FILE))
                return ext4_orphan_file_del(handle, inode);

        /* Do this quick check before taking global s_orphan_lock. */
        if (list_empty(&ei->i_orphan))
                return 0;

        if (handle) {
                /* Grab inode buffer early before taking global s_orphan_lock */
                err = ext4_reserve_inode_write(handle, inode, &iloc);
        }

        mutex_lock(&sbi->s_orphan_lock);
        jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);

        prev = ei->i_orphan.prev;
        list_del_init(&ei->i_orphan);

        /* If we're on an error path, we may not have a valid
         * transaction handle with which to update the orphan list on
         * disk, but we still need to remove the inode from the linked
         * list in memory. */
        if (!handle || err) {
                mutex_unlock(&sbi->s_orphan_lock);
                goto out_err;
        }

        ino_next = NEXT_ORPHAN(inode);
        if (prev == &sbi->s_orphan) {
                jbd_debug(4, "superblock will point to %u\n", ino_next);
                BUFFER_TRACE(sbi->s_sbh, "get_write_access");
                err = ext4_journal_get_write_access(handle, inode->i_sb,
                                                    sbi->s_sbh, EXT4_JTR_NONE);
                if (err) {
                        mutex_unlock(&sbi->s_orphan_lock);
                        goto out_brelse;
                }
                lock_buffer(sbi->s_sbh);
                sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
                ext4_superblock_csum_set(inode->i_sb);
                unlock_buffer(sbi->s_sbh);
                mutex_unlock(&sbi->s_orphan_lock);
                err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
        } else {
                struct ext4_iloc iloc2;
                struct inode *i_prev =
                        &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;

                jbd_debug(4, "orphan inode %lu will point to %u\n",
                          i_prev->i_ino, ino_next);
                err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
                if (err) {
                        mutex_unlock(&sbi->s_orphan_lock);
                        goto out_brelse;
                }
                NEXT_ORPHAN(i_prev) = ino_next;
                err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
                mutex_unlock(&sbi->s_orphan_lock);
        }
        if (err)
                goto out_brelse;
        NEXT_ORPHAN(inode) = 0;
        err = ext4_mark_iloc_dirty(handle, inode, &iloc);
out_err:
        ext4_std_error(inode->i_sb, err);
        return err;

out_brelse:
        brelse(iloc.bh);
        goto out_err;
}

#ifdef CONFIG_QUOTA
static int ext4_quota_on_mount(struct super_block *sb, int type)
{
        return dquot_quota_on_mount(sb,
                rcu_dereference_protected(EXT4_SB(sb)->s_qf_names[type],
                                          lockdep_is_held(&sb->s_umount)),
                EXT4_SB(sb)->s_jquota_fmt, type);
}
#endif

static void ext4_process_orphan(struct inode *inode,
                                int *nr_truncates, int *nr_orphans)
{
        struct super_block *sb = inode->i_sb;
        int ret;

        dquot_initialize(inode);
        if (inode->i_nlink) {
                if (test_opt(sb, DEBUG))
                        ext4_msg(sb, KERN_DEBUG,
                                "%s: truncating inode %lu to %lld bytes",
                                __func__, inode->i_ino, inode->i_size);
                jbd_debug(2, "truncating inode %lu to %lld bytes\n",
                          inode->i_ino, inode->i_size);
                inode_lock(inode);
                truncate_inode_pages(inode->i_mapping, inode->i_size);
                ret = ext4_truncate(inode);
                if (ret) {
                        /*
                         * We need to clean up the in-core orphan list
                         * manually if ext4_truncate() failed to get a
                         * transaction handle.
                         */
                        ext4_orphan_del(NULL, inode);
                        ext4_std_error(inode->i_sb, ret);
                }
                inode_unlock(inode);
                (*nr_truncates)++;
        } else {
                if (test_opt(sb, DEBUG))
                        ext4_msg(sb, KERN_DEBUG,
                                "%s: deleting unreferenced inode %lu",
                                __func__, inode->i_ino);
                jbd_debug(2, "deleting unreferenced inode %lu\n",
                          inode->i_ino);
                (*nr_orphans)++;
        }
        iput(inode);  /* The delete magic happens here! */
}

/* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
 * the superblock) which were deleted from all directories, but held open by
 * a process at the time of a crash.  We walk the list and try to delete these
 * inodes at recovery time (only with a read-write filesystem).
 *
 * In order to keep the orphan inode chain consistent during traversal (in
 * case of crash during recovery), we link each inode into the superblock
 * orphan list_head and handle it the same way as an inode deletion during
 * normal operation (which journals the operations for us).
 *
 * We only do an iget() and an iput() on each inode, which is very safe if we
 * accidentally point at an in-use or already deleted inode.  The worst that
 * can happen in this case is that we get a "bit already cleared" message from
 * ext4_free_inode().  The only reason we would point at a wrong inode is if
 * e2fsck was run on this filesystem, and it must have already done the orphan
 * inode cleanup for us, so we can safely abort without any further action.
 */
void ext4_orphan_cleanup(struct super_block *sb, struct ext4_super_block *es)
{
        unsigned int s_flags = sb->s_flags;
        int nr_orphans = 0, nr_truncates = 0;
        struct inode *inode;
        int i, j;
#ifdef CONFIG_QUOTA
        int quota_update = 0;
#endif
        __le32 *bdata;
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
        int inodes_per_ob = ext4_inodes_per_orphan_block(sb);

        if (!es->s_last_orphan && !oi->of_blocks) {
                jbd_debug(4, "no orphan inodes to clean up\n");
                return;
        }

        if (bdev_read_only(sb->s_bdev)) {
                ext4_msg(sb, KERN_ERR, "write access "
                        "unavailable, skipping orphan cleanup");
                return;
        }

        /* Check if feature set would not allow a r/w mount */
        if (!ext4_feature_set_ok(sb, 0)) {
                ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
                         "unknown ROCOMPAT features");
                return;
        }

        if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
                /* don't clear list on RO mount w/ errors */
                if (es->s_last_orphan && !(s_flags & SB_RDONLY)) {
                        ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
                                  "clearing orphan list.\n");
                        es->s_last_orphan = 0;
                }
                jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
                return;
        }

        if (s_flags & SB_RDONLY) {
                ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
                sb->s_flags &= ~SB_RDONLY;
        }
#ifdef CONFIG_QUOTA
        /*
         * Turn on quotas which were not enabled for read-only mounts if
         * filesystem has quota feature, so that they are updated correctly.
         */
        if (ext4_has_feature_quota(sb) && (s_flags & SB_RDONLY)) {
                int ret = ext4_enable_quotas(sb);

                if (!ret)
                        quota_update = 1;
                else
                        ext4_msg(sb, KERN_ERR,
                                "Cannot turn on quotas: error %d", ret);
        }

        /* Turn on journaled quotas used for old sytle */
        for (i = 0; i < EXT4_MAXQUOTAS; i++) {
                if (EXT4_SB(sb)->s_qf_names[i]) {
                        int ret = ext4_quota_on_mount(sb, i);

                        if (!ret)
                                quota_update = 1;
                        else
                                ext4_msg(sb, KERN_ERR,
                                        "Cannot turn on journaled "
                                        "quota: type %d: error %d", i, ret);
                }
        }
#endif

        while (es->s_last_orphan) {
                /*
                 * We may have encountered an error during cleanup; if
                 * so, skip the rest.
                 */
                if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
                        jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
                        es->s_last_orphan = 0;
                        break;
                }

                inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
                if (IS_ERR(inode)) {
                        es->s_last_orphan = 0;
                        break;
                }

                list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
                ext4_process_orphan(inode, &nr_truncates, &nr_orphans);
        }

        for (i = 0; i < oi->of_blocks; i++) {
                bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
                for (j = 0; j < inodes_per_ob; j++) {
                        if (!bdata[j])
                                continue;
                        inode = ext4_orphan_get(sb, le32_to_cpu(bdata[j]));
                        if (IS_ERR(inode))
                                continue;
                        ext4_set_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
                        EXT4_I(inode)->i_orphan_idx = i * inodes_per_ob + j;
                        ext4_process_orphan(inode, &nr_truncates, &nr_orphans);
                }
        }

#define PLURAL(x) (x), ((x) == 1) ? "" : "s"

        if (nr_orphans)
                ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
                       PLURAL(nr_orphans));
        if (nr_truncates)
                ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
                       PLURAL(nr_truncates));
#ifdef CONFIG_QUOTA
        /* Turn off quotas if they were enabled for orphan cleanup */
        if (quota_update) {
                for (i = 0; i < EXT4_MAXQUOTAS; i++) {
                        if (sb_dqopt(sb)->files[i])
                                dquot_quota_off(sb, i);
                }
        }
#endif
        sb->s_flags = s_flags; /* Restore SB_RDONLY status */
}

void ext4_release_orphan_info(struct super_block *sb)
{
        int i;
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;

        if (!oi->of_blocks)
                return;
        for (i = 0; i < oi->of_blocks; i++)
                brelse(oi->of_binfo[i].ob_bh);
        kfree(oi->of_binfo);
}

static struct ext4_orphan_block_tail *ext4_orphan_block_tail(
                                                struct super_block *sb,
                                                struct buffer_head *bh)
{
        return (struct ext4_orphan_block_tail *)(bh->b_data + sb->s_blocksize -
                                sizeof(struct ext4_orphan_block_tail));
}

static int ext4_orphan_file_block_csum_verify(struct super_block *sb,
                                              struct buffer_head *bh)
{
        __u32 calculated;
        int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
        struct ext4_orphan_block_tail *ot;
        __le64 dsk_block_nr = cpu_to_le64(bh->b_blocknr);

        if (!ext4_has_metadata_csum(sb))
                return 1;

        ot = ext4_orphan_block_tail(sb, bh);
        calculated = ext4_chksum(EXT4_SB(sb), oi->of_csum_seed,
                                 (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr));
        calculated = ext4_chksum(EXT4_SB(sb), calculated, (__u8 *)bh->b_data,
                                 inodes_per_ob * sizeof(__u32));
        return le32_to_cpu(ot->ob_checksum) == calculated;
}

/* This gets called only when checksumming is enabled */
void ext4_orphan_file_block_trigger(struct jbd2_buffer_trigger_type *triggers,
                                    struct buffer_head *bh,
                                    void *data, size_t size)
{
        struct super_block *sb = EXT4_TRIGGER(triggers)->sb;
        __u32 csum;
        int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
        struct ext4_orphan_block_tail *ot;
        __le64 dsk_block_nr = cpu_to_le64(bh->b_blocknr);

        csum = ext4_chksum(EXT4_SB(sb), oi->of_csum_seed,
                           (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr));
        csum = ext4_chksum(EXT4_SB(sb), csum, (__u8 *)data,
                           inodes_per_ob * sizeof(__u32));
        ot = ext4_orphan_block_tail(sb, bh);
        ot->ob_checksum = cpu_to_le32(csum);
}

int ext4_init_orphan_info(struct super_block *sb)
{
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
        struct inode *inode;
        int i, j;
        int ret;
        int free;
        __le32 *bdata;
        int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
        struct ext4_orphan_block_tail *ot;
        ino_t orphan_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_orphan_file_inum);

        if (!ext4_has_feature_orphan_file(sb))
                return 0;

        inode = ext4_iget(sb, orphan_ino, EXT4_IGET_SPECIAL);
        if (IS_ERR(inode)) {
                ext4_msg(sb, KERN_ERR, "get orphan inode failed");
                return PTR_ERR(inode);
        }
        oi->of_blocks = inode->i_size >> sb->s_blocksize_bits;
        oi->of_csum_seed = EXT4_I(inode)->i_csum_seed;
        oi->of_binfo = kmalloc(oi->of_blocks*sizeof(struct ext4_orphan_block),
                               GFP_KERNEL);
        if (!oi->of_binfo) {
                ret = -ENOMEM;
                goto out_put;
        }
        for (i = 0; i < oi->of_blocks; i++) {
                oi->of_binfo[i].ob_bh = ext4_bread(NULL, inode, i, 0);
                if (IS_ERR(oi->of_binfo[i].ob_bh)) {
                        ret = PTR_ERR(oi->of_binfo[i].ob_bh);
                        goto out_free;
                }
                if (!oi->of_binfo[i].ob_bh) {
                        ret = -EIO;
                        goto out_free;
                }
                ot = ext4_orphan_block_tail(sb, oi->of_binfo[i].ob_bh);
                if (le32_to_cpu(ot->ob_magic) != EXT4_ORPHAN_BLOCK_MAGIC) {
                        ext4_error(sb, "orphan file block %d: bad magic", i);
                        ret = -EIO;
                        goto out_free;
                }
                if (!ext4_orphan_file_block_csum_verify(sb,
                                                oi->of_binfo[i].ob_bh)) {
                        ext4_error(sb, "orphan file block %d: bad checksum", i);
                        ret = -EIO;
                        goto out_free;
                }
                bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
                free = 0;
                for (j = 0; j < inodes_per_ob; j++)
                        if (bdata[j] == 0)
                                free++;
                atomic_set(&oi->of_binfo[i].ob_free_entries, free);
        }
        iput(inode);
        return 0;
out_free:
        for (i--; i >= 0; i--)
                brelse(oi->of_binfo[i].ob_bh);
        kfree(oi->of_binfo);
out_put:
        iput(inode);
        return ret;
}

int ext4_orphan_file_empty(struct super_block *sb)
{
        struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
        int i;
        int inodes_per_ob = ext4_inodes_per_orphan_block(sb);

        if (!ext4_has_feature_orphan_file(sb))
                return 1;
        for (i = 0; i < oi->of_blocks; i++)
                if (atomic_read(&oi->of_binfo[i].ob_free_entries) !=
                    inodes_per_ob)
                        return 0;
        return 1;
}