/* SPDX-License-Identifier: GPL-2.0 */

#ifndef BTRFS_BLOCK_GROUP_H
#define BTRFS_BLOCK_GROUP_H

#include <linux/atomic.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/refcount.h>
#include <linux/wait.h>
#include <linux/sizes.h>
#include <linux/rwsem.h>
#include <linux/rbtree.h>
#include <uapi/linux/btrfs_tree.h>
#include "free-space-cache.h"

struct btrfs_chunk_map;
struct btrfs_fs_info;
struct btrfs_inode;
struct btrfs_trans_handle;

enum btrfs_disk_cache_state {
        BTRFS_DC_WRITTEN,
        BTRFS_DC_ERROR,
        BTRFS_DC_CLEAR,
        BTRFS_DC_SETUP,
};

enum btrfs_block_group_size_class {
        /* Unset */
        BTRFS_BG_SZ_NONE,
        /* 0 < size <= 128K */
        BTRFS_BG_SZ_SMALL,
        /* 128K < size <= 8M */
        BTRFS_BG_SZ_MEDIUM,
        /* 8M < size < BG_LENGTH */
        BTRFS_BG_SZ_LARGE,
};

/*
 * This describes the state of the block_group for async discard.  This is due
 * to the two pass nature of it where extent discarding is prioritized over
 * bitmap discarding.  BTRFS_DISCARD_RESET_CURSOR is set when we are resetting
 * between lists to prevent contention for discard state variables
 * (eg. discard_cursor).
 */
enum btrfs_discard_state {
        BTRFS_DISCARD_EXTENTS,
        BTRFS_DISCARD_BITMAPS,
        BTRFS_DISCARD_RESET_CURSOR,
        BTRFS_DISCARD_FULLY_REMAPPED,
};

/*
 * Control flags for do_chunk_alloc's force field CHUNK_ALLOC_NO_FORCE means to
 * only allocate a chunk if we really need one.
 *
 * CHUNK_ALLOC_LIMITED means to only try and allocate one if we have very few
 * chunks already allocated.  This is used as part of the clustering code to
 * help make sure we have a good pool of storage to cluster in, without filling
 * the FS with empty chunks
 *
 * CHUNK_ALLOC_FORCE means it must try to allocate one
 *
 * CHUNK_ALLOC_FORCE_FOR_EXTENT like CHUNK_ALLOC_FORCE but called from
 * find_free_extent() that also activates the zone
 */
enum btrfs_chunk_alloc_enum {
        CHUNK_ALLOC_NO_FORCE,
        CHUNK_ALLOC_LIMITED,
        CHUNK_ALLOC_FORCE,
        CHUNK_ALLOC_FORCE_FOR_EXTENT,
};

/* Block group flags set at runtime */
enum btrfs_block_group_flags {
        BLOCK_GROUP_FLAG_IREF,
        BLOCK_GROUP_FLAG_REMOVED,
        BLOCK_GROUP_FLAG_TO_COPY,
        BLOCK_GROUP_FLAG_RELOCATING_REPAIR,
        BLOCK_GROUP_FLAG_CHUNK_ITEM_INSERTED,
        BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
        BLOCK_GROUP_FLAG_ZONED_DATA_RELOC,
        /* Does the block group need to be added to the free space tree? */
        BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE,
        /* Set after we add a new block group to the free space tree. */
        BLOCK_GROUP_FLAG_FREE_SPACE_ADDED,
        /* Indicate that the block group is placed on a sequential zone */
        BLOCK_GROUP_FLAG_SEQUENTIAL_ZONE,
        /*
         * Indicate that block group is in the list of new block groups of a
         * transaction.
         */
        BLOCK_GROUP_FLAG_NEW,
        BLOCK_GROUP_FLAG_FULLY_REMAPPED,
        BLOCK_GROUP_FLAG_STRIPE_REMOVAL_PENDING,
};

enum btrfs_caching_type {
        BTRFS_CACHE_NO,
        BTRFS_CACHE_STARTED,
        BTRFS_CACHE_FINISHED,
        BTRFS_CACHE_ERROR,
};

struct btrfs_caching_control {
        struct list_head list;
        struct mutex mutex;
        wait_queue_head_t wait;
        struct btrfs_work work;
        struct btrfs_block_group *block_group;
        /* Track progress of caching during allocation. */
        atomic_t progress;
        refcount_t count;
};

/* Once caching_thread() finds this much free space, it will wake up waiters. */
#define CACHING_CTL_WAKE_UP SZ_2M

struct btrfs_block_group {
        struct btrfs_fs_info *fs_info;
        struct btrfs_inode *inode;
        spinlock_t lock;
        u64 start;
        u64 length;
        u64 pinned;
        u64 reserved;
        u64 used;
        u64 delalloc_bytes;
        u64 bytes_super;
        u64 flags;
        u64 cache_generation;
        u64 global_root_id;
        u64 remap_bytes;
        u32 identity_remap_count;

        /*
         * The last committed used bytes of this block group, if the above @used
         * is still the same as @last_used, we don't need to update block
         * group item of this block group.
         */
        u64 last_used;
        /* The last committed remap_bytes value of this block group. */
        u64 last_remap_bytes;
        /* The last commited identity_remap_count value of this block group. */
        u32 last_identity_remap_count;
        /* The last committed flags value for this block group. */
        u64 last_flags;

        /*
         * If the free space extent count exceeds this number, convert the block
         * group to bitmaps.
         */
        u32 bitmap_high_thresh;

        /*
         * If the free space extent count drops below this number, convert the
         * block group back to extents.
         */
        u32 bitmap_low_thresh;

        /*
         * It is just used for the delayed data space allocation because
         * only the data space allocation and the relative metadata update
         * can be done cross the transaction.
         */
        struct rw_semaphore data_rwsem;

        /* For raid56, this is a full stripe, without parity */
        unsigned long full_stripe_len;
        unsigned long runtime_flags;

        unsigned int ro;

        int disk_cache_state;

        /* Cache tracking stuff */
        int cached;
        struct btrfs_caching_control *caching_ctl;

        struct btrfs_space_info *space_info;

        /* Free space cache stuff */
        struct btrfs_free_space_ctl *free_space_ctl;

        /* Block group cache stuff */
        struct rb_node cache_node;

        /* For block groups in the same raid type */
        struct list_head list;

        refcount_t refs;

        /*
         * List of struct btrfs_free_clusters for this block group.
         * Today it will only have one thing on it, but that may change
         */
        struct list_head cluster_list;

        /*
         * Used for several lists:
         *
         * 1) struct btrfs_fs_info::unused_bgs
         * 2) struct btrfs_fs_info::reclaim_bgs
         * 3) struct btrfs_transaction::deleted_bgs
         * 4) struct btrfs_trans_handle::new_bgs
         */
        struct list_head bg_list;

        /* For read-only block groups */
        struct list_head ro_list;

        /*
         * When non-zero it means the block group's logical address and its
         * device extents can not be reused for future block group allocations
         * until the counter goes down to 0. This is to prevent them from being
         * reused while some task is still using the block group after it was
         * deleted - we want to make sure they can only be reused for new block
         * groups after that task is done with the deleted block group.
         */
        atomic_t frozen;

        /* For discard operations */
        struct list_head discard_list;
        int discard_index;
        u64 discard_eligible_time;
        u64 discard_cursor;
        enum btrfs_discard_state discard_state;

        /* For dirty block groups */
        struct list_head dirty_list;
        struct list_head io_list;

        struct btrfs_io_ctl io_ctl;

        /*
         * Incremented when doing extent allocations and holding a read lock
         * on the space_info's groups_sem semaphore.
         * Decremented when an ordered extent that represents an IO against this
         * block group's range is created (after it's added to its inode's
         * root's list of ordered extents) or immediately after the allocation
         * if it's a metadata extent or fallocate extent (for these cases we
         * don't create ordered extents).
         */
        atomic_t reservations;

        /*
         * Incremented while holding the spinlock *lock* by a task checking if
         * it can perform a nocow write (incremented if the value for the *ro*
         * field is 0). Decremented by such tasks once they create an ordered
         * extent or before that if some error happens before reaching that step.
         * This is to prevent races between block group relocation and nocow
         * writes through direct IO.
         */
        atomic_t nocow_writers;

        /* Lock for free space tree operations. */
        struct mutex free_space_lock;

        /* Protected by @free_space_lock. */
        bool using_free_space_bitmaps;
        /* Protected by @free_space_lock. */
        bool using_free_space_bitmaps_cached;

        /*
         * Number of extents in this block group used for swap files.
         * All accesses protected by the spinlock 'lock'.
         */
        int swap_extents;

        /*
         * Allocation offset for the block group to implement sequential
         * allocation. This is used only on a zoned filesystem.
         */
        u64 alloc_offset;
        u64 zone_unusable;
        u64 zone_capacity;
        u64 meta_write_pointer;
        struct btrfs_chunk_map *physical_map;
        struct list_head active_bg_list;
        struct work_struct zone_finish_work;
        struct extent_buffer *last_eb;
        enum btrfs_block_group_size_class size_class;
        u64 reclaim_mark;
};

static inline u64 btrfs_block_group_end(const struct btrfs_block_group *block_group)
{
        return (block_group->start + block_group->length);
}

static inline bool btrfs_is_block_group_used(const struct btrfs_block_group *bg)
{
        lockdep_assert_held(&bg->lock);

        return (bg->used > 0 || bg->reserved > 0 || bg->pinned > 0 ||
                bg->remap_bytes > 0);
}

static inline bool btrfs_is_block_group_data_only(const struct btrfs_block_group *block_group)
{
        /*
         * In mixed mode the fragmentation is expected to be high, lowering the
         * efficiency, so only proper data block groups are considered.
         */
        return (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&
               !(block_group->flags & BTRFS_BLOCK_GROUP_METADATA);
}

static inline u64 btrfs_block_group_available_space(const struct btrfs_block_group *bg)
{
        lockdep_assert_held(&bg->lock);

        return (bg->length - bg->used - bg->pinned - bg->reserved -
                bg->bytes_super - bg->zone_unusable);
}

#ifdef CONFIG_BTRFS_DEBUG
int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group);
#endif

struct btrfs_block_group *btrfs_lookup_first_block_group(
                struct btrfs_fs_info *info, u64 bytenr);
struct btrfs_block_group *btrfs_lookup_block_group(
                struct btrfs_fs_info *info, u64 bytenr);
struct btrfs_block_group *btrfs_next_block_group(
                struct btrfs_block_group *cache);
void btrfs_get_block_group(struct btrfs_block_group *cache);
void btrfs_put_block_group(struct btrfs_block_group *cache);
void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
                                        const u64 start);
void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg);
struct btrfs_block_group *btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info,
                                                  u64 bytenr);
void btrfs_dec_nocow_writers(struct btrfs_block_group *bg);
void btrfs_wait_nocow_writers(struct btrfs_block_group *bg);
void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
                                           u64 num_bytes);
int btrfs_cache_block_group(struct btrfs_block_group *cache, bool wait);
struct btrfs_caching_control *btrfs_get_caching_control(
                struct btrfs_block_group *cache);
int btrfs_add_new_free_space(struct btrfs_block_group *block_group,
                             u64 start, u64 end, u64 *total_added_ret);
struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
                                struct btrfs_fs_info *fs_info,
                                const u64 chunk_offset);
void btrfs_remove_bg_from_sinfo(struct btrfs_block_group *bg);
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
                             struct btrfs_chunk_map *map);
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info);
void btrfs_mark_bg_unused(struct btrfs_block_group *bg);
void btrfs_reclaim_bgs_work(struct work_struct *work);
void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info);
void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg);
int btrfs_read_block_groups(struct btrfs_fs_info *info);
struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans,
                                                 struct btrfs_space_info *space_info,
                                                 u64 type, u64 chunk_offset, u64 size);
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans);
int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
                             bool do_chunk_alloc);
void btrfs_dec_block_group_ro(struct btrfs_block_group *cache);
int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans);
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans);
int btrfs_setup_space_cache(struct btrfs_trans_handle *trans);
int btrfs_update_block_group(struct btrfs_trans_handle *trans,
                             u64 bytenr, u64 num_bytes, bool alloc);
int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
                             u64 ram_bytes, u64 num_bytes, bool delalloc,
                             bool force_wrong_size_class);
void btrfs_free_reserved_bytes(struct btrfs_block_group *cache, u64 num_bytes,
                               bool is_delalloc);
int btrfs_chunk_alloc(struct btrfs_trans_handle *trans,
                      struct btrfs_space_info *space_info, u64 flags,
                      enum btrfs_chunk_alloc_enum force);
int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type);
void check_system_chunk(struct btrfs_trans_handle *trans, const u64 type);
void btrfs_reserve_chunk_metadata(struct btrfs_trans_handle *trans,
                                  bool is_item_insertion);
u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags);
void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
int btrfs_free_block_groups(struct btrfs_fs_info *info);
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
                     u64 physical, u64 **logical, int *naddrs, int *stripe_len);

static inline u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
{
        return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
}

static inline u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
{
        return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
}

static inline u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
{
        return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
}

static inline int btrfs_block_group_done(const struct btrfs_block_group *cache)
{
        smp_mb();
        return cache->cached == BTRFS_CACHE_FINISHED ||
                cache->cached == BTRFS_CACHE_ERROR;
}

void btrfs_freeze_block_group(struct btrfs_block_group *cache);
void btrfs_unfreeze_block_group(struct btrfs_block_group *cache);

bool btrfs_inc_block_group_swap_extents(struct btrfs_block_group *bg);
void btrfs_dec_block_group_swap_extents(struct btrfs_block_group *bg, int amount);

enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size);
int btrfs_use_block_group_size_class(struct btrfs_block_group *bg,
                                     enum btrfs_block_group_size_class size_class,
                                     bool force_wrong_size_class);
bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg);
void btrfs_mark_bg_fully_remapped(struct btrfs_block_group *bg,
                                  struct btrfs_trans_handle *trans);
int btrfs_populate_fully_remapped_bgs_list(struct btrfs_fs_info *fs_info);

#endif /* BTRFS_BLOCK_GROUP_H */