// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) Tino Reichardt, 2012
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/blkdev.h>

#include "jfs_incore.h"
#include "jfs_superblock.h"
#include "jfs_discard.h"
#include "jfs_dmap.h"
#include "jfs_debug.h"


/*
 * NAME:        jfs_issue_discard()
 *
 * FUNCTION:    TRIM the specified block range on device, if supported
 *
 * PARAMETERS:
 *      ip      - pointer to in-core inode
 *      blkno   - starting block number to be trimmed (0..N)
 *      nblocks - number of blocks to be trimmed
 *
 * RETURN VALUES:
 *      none
 *
 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
 */
void jfs_issue_discard(struct inode *ip, u64 blkno, u64 nblocks)
{
        struct super_block *sb = ip->i_sb;
        int r = 0;

        r = sb_issue_discard(sb, blkno, nblocks, GFP_NOFS, 0);
        if (unlikely(r != 0)) {
                jfs_err("JFS: sb_issue_discard(%p, %llu, %llu, GFP_NOFS, 0) = %d => failed!",
                        sb, (unsigned long long)blkno,
                        (unsigned long long)nblocks, r);
        }

        jfs_info("JFS: sb_issue_discard(%p, %llu, %llu, GFP_NOFS, 0) = %d",
                sb, (unsigned long long)blkno,
                (unsigned long long)nblocks, r);

        return;
}

/*
 * NAME:        jfs_ioc_trim()
 *
 * FUNCTION:    attempt to discard (TRIM) all free blocks from the
 *              filesystem.
 *
 * PARAMETERS:
 *      ip      - pointer to in-core inode;
 *      range   - the range, given by user space
 *
 * RETURN VALUES:
 *      0       - success
 *      -EIO    - i/o error
 */
int jfs_ioc_trim(struct inode *ip, struct fstrim_range *range)
{
        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
        struct bmap *bmp;
        struct super_block *sb = ipbmap->i_sb;
        int agno, agno_end;
        u64 start, end, minlen;
        u64 trimmed = 0;

        /**
         * convert byte values to block size of filesystem:
         * start:       First Byte to trim
         * len:         number of Bytes to trim from start
         * minlen:      minimum extent length in Bytes
         */
        start = range->start >> sb->s_blocksize_bits;
        end = start + (range->len >> sb->s_blocksize_bits) - 1;
        minlen = range->minlen >> sb->s_blocksize_bits;
        if (minlen == 0)
                minlen = 1;

        down_read(&sb->s_umount);
        bmp = JFS_SBI(ip->i_sb)->bmap;

        if (bmp == NULL ||
            minlen > bmp->db_agsize ||
            start >= bmp->db_mapsize ||
            range->len < sb->s_blocksize) {
                up_read(&sb->s_umount);
                return -EINVAL;
        }

        if (end >= bmp->db_mapsize)
                end = bmp->db_mapsize - 1;

        /**
         * we trim all ag's within the range
         */
        agno = BLKTOAG(start, JFS_SBI(ip->i_sb));
        agno_end = BLKTOAG(end, JFS_SBI(ip->i_sb));
        while (agno <= agno_end) {
                trimmed += dbDiscardAG(ip, agno, minlen);
                agno++;
        }

        up_read(&sb->s_umount);
        range->len = trimmed << sb->s_blocksize_bits;

        return 0;
}