// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2016 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */
#ifndef __XFS_REFCOUNT_H__
#define __XFS_REFCOUNT_H__

struct xfs_trans;
struct xfs_mount;
struct xfs_perag;
struct xfs_btree_cur;
struct xfs_bmbt_irec;
struct xfs_refcount_irec;
struct xfs_rtgroup;

extern int xfs_refcount_lookup_le(struct xfs_btree_cur *cur,
                enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
extern int xfs_refcount_lookup_ge(struct xfs_btree_cur *cur,
                enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
extern int xfs_refcount_lookup_eq(struct xfs_btree_cur *cur,
                enum xfs_refc_domain domain, xfs_agblock_t bno, int *stat);
extern int xfs_refcount_get_rec(struct xfs_btree_cur *cur,
                struct xfs_refcount_irec *irec, int *stat);

static inline uint32_t
xfs_refcount_encode_startblock(
        xfs_agblock_t           startblock,
        enum xfs_refc_domain    domain)
{
        uint32_t                start;

        /*
         * low level btree operations need to handle the generic btree range
         * query functions (which set rc_domain == -1U), so we check that the
         * domain is /not/ shared.
         */
        start = startblock & ~XFS_REFC_COWFLAG;
        if (domain != XFS_REFC_DOMAIN_SHARED)
                start |= XFS_REFC_COWFLAG;

        return start;
}

enum xfs_refcount_intent_type {
        XFS_REFCOUNT_INCREASE = 1,
        XFS_REFCOUNT_DECREASE,
        XFS_REFCOUNT_ALLOC_COW,
        XFS_REFCOUNT_FREE_COW,
};

#define XFS_REFCOUNT_INTENT_STRINGS \
        { XFS_REFCOUNT_INCREASE,        "incr" }, \
        { XFS_REFCOUNT_DECREASE,        "decr" }, \
        { XFS_REFCOUNT_ALLOC_COW,       "alloc_cow" }, \
        { XFS_REFCOUNT_FREE_COW,        "free_cow" }

struct xfs_refcount_intent {
        struct list_head                        ri_list;
        struct xfs_group                        *ri_group;
        enum xfs_refcount_intent_type           ri_type;
        xfs_extlen_t                            ri_blockcount;
        xfs_fsblock_t                           ri_startblock;
        bool                                    ri_realtime;
};

/* Check that the refcount is appropriate for the record domain. */
static inline bool
xfs_refcount_check_domain(
        const struct xfs_refcount_irec  *irec)
{
        if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
                return false;
        if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
                return false;
        return true;
}

void xfs_refcount_increase_extent(struct xfs_trans *tp, bool isrt,
                struct xfs_bmbt_irec *irec);
void xfs_refcount_decrease_extent(struct xfs_trans *tp, bool isrt,
                struct xfs_bmbt_irec *irec);

int xfs_refcount_finish_one(struct xfs_trans *tp,
                struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);
int xfs_rtrefcount_finish_one(struct xfs_trans *tp,
                struct xfs_refcount_intent *ri, struct xfs_btree_cur **pcur);

extern int xfs_refcount_find_shared(struct xfs_btree_cur *cur,
                xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
                xfs_extlen_t *flen, bool find_end_of_shared);

void xfs_refcount_alloc_cow_extent(struct xfs_trans *tp, bool isrt,
                xfs_fsblock_t fsb, xfs_extlen_t len);
void xfs_refcount_free_cow_extent(struct xfs_trans *tp, bool isrt,
                xfs_fsblock_t fsb, xfs_extlen_t len);
int xfs_refcount_recover_cow_leftovers(struct xfs_group *xg);

/*
 * While we're adjusting the refcounts records of an extent, we have
 * to keep an eye on the number of extents we're dirtying -- run too
 * many in a single transaction and we'll exceed the transaction's
 * reservation and crash the fs.  Each record adds 12 bytes to the
 * log (plus any key updates) so we'll conservatively assume 32 bytes
 * per record.  We must also leave space for btree splits on both ends
 * of the range and space for the CUD and a new CUI.
 *
 * Each EFI that we attach to the transaction is assumed to consume ~32 bytes.
 * This is a low estimate for an EFI tracking a single extent (16 bytes for the
 * EFI header, 16 for the extent, and 12 for the xlog op header), but the
 * estimate is acceptable if there's more than one extent being freed.
 * In the worst case of freeing every other block during a refcount decrease
 * operation, we amortize the space used for one EFI log item across 16
 * extents.
 */
#define XFS_REFCOUNT_ITEM_OVERHEAD      32

extern int xfs_refcount_has_records(struct xfs_btree_cur *cur,
                enum xfs_refc_domain domain, xfs_agblock_t bno,
                xfs_extlen_t len, enum xbtree_recpacking *outcome);
union xfs_btree_rec;
extern void xfs_refcount_btrec_to_irec(const union xfs_btree_rec *rec,
                struct xfs_refcount_irec *irec);
xfs_failaddr_t xfs_refcount_check_irec(struct xfs_perag *pag,
                const struct xfs_refcount_irec *irec);
xfs_failaddr_t xfs_rtrefcount_check_irec(struct xfs_rtgroup *rtg,
                const struct xfs_refcount_irec *irec);
extern int xfs_refcount_insert(struct xfs_btree_cur *cur,
                struct xfs_refcount_irec *irec, int *stat);

extern struct kmem_cache        *xfs_refcount_intent_cache;

int __init xfs_refcount_intent_init_cache(void);
void xfs_refcount_intent_destroy_cache(void);

typedef int (*xfs_refcount_query_range_fn)(
        struct xfs_btree_cur            *cur,
        const struct xfs_refcount_irec  *rec,
        void                            *priv);

int xfs_refcount_query_range(struct xfs_btree_cur *cur,
                const struct xfs_refcount_irec *low_rec,
                const struct xfs_refcount_irec *high_rec,
                xfs_refcount_query_range_fn fn, void *priv);

#endif  /* __XFS_REFCOUNT_H__ */