// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2022-2024 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <djwong@kernel.org>
 */
#include "xfs_platform.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_btree.h"
#include "xfs_buf_mem.h"
#include "xfs_btree_mem.h"
#include "xfs_error.h"
#include "scrub/rcbag_btree.h"
#include "scrub/trace.h"

static struct kmem_cache        *rcbagbt_cur_cache;

STATIC void
rcbagbt_init_key_from_rec(
        union xfs_btree_key             *key,
        const union xfs_btree_rec       *rec)
{
        struct rcbag_key        *bag_key = (struct rcbag_key *)key;
        const struct rcbag_rec  *bag_rec = (const struct rcbag_rec *)rec;

        BUILD_BUG_ON(sizeof(struct rcbag_key) > sizeof(union xfs_btree_key));
        BUILD_BUG_ON(sizeof(struct rcbag_rec) > sizeof(union xfs_btree_rec));

        bag_key->rbg_startblock = bag_rec->rbg_startblock;
        bag_key->rbg_blockcount = bag_rec->rbg_blockcount;
}

STATIC void
rcbagbt_init_rec_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_rec     *rec)
{
        struct rcbag_rec        *bag_rec = (struct rcbag_rec *)rec;
        struct rcbag_rec        *bag_irec = (struct rcbag_rec *)&cur->bc_rec;

        bag_rec->rbg_startblock = bag_irec->rbg_startblock;
        bag_rec->rbg_blockcount = bag_irec->rbg_blockcount;
        bag_rec->rbg_refcount = bag_irec->rbg_refcount;
}

STATIC int
rcbagbt_cmp_key_with_cur(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *key)
{
        struct rcbag_rec                *rec = (struct rcbag_rec *)&cur->bc_rec;
        const struct rcbag_key          *kp = (const struct rcbag_key *)key;

        return cmp_int(kp->rbg_startblock, rec->rbg_startblock) ?:
               cmp_int(kp->rbg_blockcount, rec->rbg_blockcount);
}

STATIC int
rcbagbt_cmp_two_keys(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *k1,
        const union xfs_btree_key       *k2,
        const union xfs_btree_key       *mask)
{
        const struct rcbag_key          *kp1 = (const struct rcbag_key *)k1;
        const struct rcbag_key          *kp2 = (const struct rcbag_key *)k2;

        ASSERT(mask == NULL);

        return cmp_int(kp1->rbg_startblock, kp2->rbg_startblock) ?:
               cmp_int(kp1->rbg_blockcount, kp2->rbg_blockcount);
}

STATIC int
rcbagbt_keys_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *k1,
        const union xfs_btree_key       *k2)
{
        const struct rcbag_key          *kp1 = (const struct rcbag_key *)k1;
        const struct rcbag_key          *kp2 = (const struct rcbag_key *)k2;

        if (kp1->rbg_startblock > kp2->rbg_startblock)
                return 0;
        if (kp1->rbg_startblock < kp2->rbg_startblock)
                return 1;

        if (kp1->rbg_blockcount > kp2->rbg_blockcount)
                return 0;
        if (kp1->rbg_blockcount < kp2->rbg_blockcount)
                return 1;

        return 0;
}

STATIC int
rcbagbt_recs_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_rec       *r1,
        const union xfs_btree_rec       *r2)
{
        const struct rcbag_rec          *rp1 = (const struct rcbag_rec *)r1;
        const struct rcbag_rec          *rp2 = (const struct rcbag_rec *)r2;

        if (rp1->rbg_startblock > rp2->rbg_startblock)
                return 0;
        if (rp1->rbg_startblock < rp2->rbg_startblock)
                return 1;

        if (rp1->rbg_blockcount > rp2->rbg_blockcount)
                return 0;
        if (rp1->rbg_blockcount < rp2->rbg_blockcount)
                return 1;

        return 0;
}

static xfs_failaddr_t
rcbagbt_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
        xfs_failaddr_t          fa;
        unsigned int            level;
        unsigned int            maxrecs;

        if (!xfs_verify_magic(bp, block->bb_magic))
                return __this_address;

        fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
        if (fa)
                return fa;

        level = be16_to_cpu(block->bb_level);
        if (level >= rcbagbt_maxlevels_possible())
                return __this_address;

        maxrecs = rcbagbt_maxrecs(mp, XFBNO_BLOCKSIZE, level == 0);
        return xfs_btree_memblock_verify(bp, maxrecs);
}

static void
rcbagbt_rw_verify(
        struct xfs_buf  *bp)
{
        xfs_failaddr_t  fa = rcbagbt_verify(bp);

        if (fa)
                xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}

/* skip crc checks on in-memory btrees to save time */
static const struct xfs_buf_ops rcbagbt_mem_buf_ops = {
        .name                   = "rcbagbt_mem",
        .magic                  = { 0, cpu_to_be32(RCBAG_MAGIC) },
        .verify_read            = rcbagbt_rw_verify,
        .verify_write           = rcbagbt_rw_verify,
        .verify_struct          = rcbagbt_verify,
};

static const struct xfs_btree_ops rcbagbt_mem_ops = {
        .name                   = "rcbag",
        .type                   = XFS_BTREE_TYPE_MEM,

        .rec_len                = sizeof(struct rcbag_rec),
        .key_len                = sizeof(struct rcbag_key),
        .ptr_len                = XFS_BTREE_LONG_PTR_LEN,

        .lru_refs               = 1,
        .statoff                = XFS_STATS_CALC_INDEX(xs_rcbag_2),

        .dup_cursor             = xfbtree_dup_cursor,
        .set_root               = xfbtree_set_root,
        .alloc_block            = xfbtree_alloc_block,
        .free_block             = xfbtree_free_block,
        .get_minrecs            = xfbtree_get_minrecs,
        .get_maxrecs            = xfbtree_get_maxrecs,
        .init_key_from_rec      = rcbagbt_init_key_from_rec,
        .init_rec_from_cur      = rcbagbt_init_rec_from_cur,
        .init_ptr_from_cur      = xfbtree_init_ptr_from_cur,
        .cmp_key_with_cur       = rcbagbt_cmp_key_with_cur,
        .buf_ops                = &rcbagbt_mem_buf_ops,
        .cmp_two_keys           = rcbagbt_cmp_two_keys,
        .keys_inorder           = rcbagbt_keys_inorder,
        .recs_inorder           = rcbagbt_recs_inorder,
};

/* Create a cursor for an in-memory btree. */
struct xfs_btree_cur *
rcbagbt_mem_cursor(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        struct xfbtree          *xfbtree)
{
        struct xfs_btree_cur    *cur;

        cur = xfs_btree_alloc_cursor(mp, tp, &rcbagbt_mem_ops,
                        rcbagbt_maxlevels_possible(), rcbagbt_cur_cache);

        cur->bc_mem.xfbtree = xfbtree;
        cur->bc_nlevels = xfbtree->nlevels;
        return cur;
}

/* Create an in-memory refcount bag btree. */
int
rcbagbt_mem_init(
        struct xfs_mount        *mp,
        struct xfbtree          *xfbt,
        struct xfs_buftarg      *btp)
{
        xfbt->owner = 0;
        return xfbtree_init(mp, xfbt, btp, &rcbagbt_mem_ops);
}

/* Calculate number of records in a refcount bag btree block. */
static inline unsigned int
rcbagbt_block_maxrecs(
        unsigned int            blocklen,
        bool                    leaf)
{
        if (leaf)
                return blocklen / sizeof(struct rcbag_rec);
        return blocklen /
                (sizeof(struct rcbag_key) + sizeof(rcbag_ptr_t));
}

/*
 * Calculate number of records in an refcount bag btree block.
 */
unsigned int
rcbagbt_maxrecs(
        struct xfs_mount        *mp,
        unsigned int            blocklen,
        bool                    leaf)
{
        blocklen -= RCBAG_BLOCK_LEN;
        return rcbagbt_block_maxrecs(blocklen, leaf);
}

/* Compute the max possible height for refcount bag btrees. */
unsigned int
rcbagbt_maxlevels_possible(void)
{
        unsigned int            minrecs[2];
        unsigned int            blocklen;

        blocklen = XFBNO_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;

        minrecs[0] = rcbagbt_block_maxrecs(blocklen, true) / 2;
        minrecs[1] = rcbagbt_block_maxrecs(blocklen, false) / 2;

        return xfs_btree_space_to_height(minrecs, ULLONG_MAX);
}

/* Calculate the refcount bag btree size for some records. */
unsigned long long
rcbagbt_calc_size(
        unsigned long long      nr_records)
{
        unsigned int            minrecs[2];
        unsigned int            blocklen;

        blocklen = XFBNO_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;

        minrecs[0] = rcbagbt_block_maxrecs(blocklen, true) / 2;
        minrecs[1] = rcbagbt_block_maxrecs(blocklen, false) / 2;

        return xfs_btree_calc_size(minrecs, nr_records);
}

int __init
rcbagbt_init_cur_cache(void)
{
        rcbagbt_cur_cache = kmem_cache_create("xfs_rcbagbt_cur",
                        xfs_btree_cur_sizeof(rcbagbt_maxlevels_possible()),
                        0, 0, NULL);

        if (!rcbagbt_cur_cache)
                return -ENOMEM;
        return 0;
}

void
rcbagbt_destroy_cur_cache(void)
{
        kmem_cache_destroy(rcbagbt_cur_cache);
        rcbagbt_cur_cache = NULL;
}

/* Look up the refcount bag record corresponding to this reverse mapping. */
int
rcbagbt_lookup_eq(
        struct xfs_btree_cur            *cur,
        const struct xfs_rmap_irec      *rmap,
        int                             *success)
{
        struct rcbag_rec                *rec = (struct rcbag_rec *)&cur->bc_rec;

        rec->rbg_startblock = rmap->rm_startblock;
        rec->rbg_blockcount = rmap->rm_blockcount;

        return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, success);
}

/* Get the data from the pointed-to record. */
int
rcbagbt_get_rec(
        struct xfs_btree_cur    *cur,
        struct rcbag_rec        *rec,
        int                     *has)
{
        union xfs_btree_rec     *btrec;
        int                     error;

        error = xfs_btree_get_rec(cur, &btrec, has);
        if (error || !(*has))
                return error;

        memcpy(rec, btrec, sizeof(struct rcbag_rec));
        return 0;
}

/* Update the record referred to by cur to the value given. */
int
rcbagbt_update(
        struct xfs_btree_cur    *cur,
        const struct rcbag_rec  *rec)
{
        union xfs_btree_rec     btrec;

        memcpy(&btrec, rec, sizeof(struct rcbag_rec));
        return xfs_btree_update(cur, &btrec);
}

/* Update the record referred to by cur to the value given. */
int
rcbagbt_insert(
        struct xfs_btree_cur    *cur,
        const struct rcbag_rec  *rec,
        int                     *success)
{
        struct rcbag_rec        *btrec = (struct rcbag_rec *)&cur->bc_rec;

        memcpy(btrec, rec, sizeof(struct rcbag_rec));
        return xfs_btree_insert(cur, success);
}