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

#ifndef BTRFS_BLOCK_GROUP_H
#define BTRFS_BLOCK_GROUP_H

#include "free-space-cache.h"

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

/*
 * 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,
};

/*
 * 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
 */
enum btrfs_chunk_alloc_enum {
        CHUNK_ALLOC_NO_FORCE,
        CHUNK_ALLOC_LIMITED,
        CHUNK_ALLOC_FORCE,
};

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;
        u64 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 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;

        /*
         * 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 int ro;
        unsigned int iref:1;
        unsigned int has_caching_ctl:1;
        unsigned int removed:1;
        unsigned int to_copy:1;
        unsigned int relocating_repair:1;
        unsigned int chunk_item_inserted:1;

        int disk_cache_state;

        /* Cache tracking stuff */
        int cached;
        struct btrfs_caching_control *caching_ctl;
        u64 last_byte_to_unpin;

        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;

        /* For delayed block group creation or deletion of empty block groups */
        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;

        /*
         * Does the block group need to be added to the free space tree?
         * Protected by free_space_lock.
         */
        int needs_free_space;

        /* Flag indicating this block group is placed on a sequential zone */
        bool seq_zone;

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

        /* Record locked full stripes for RAID5/6 block group */
        struct btrfs_full_stripe_locks_tree full_stripe_locks_root;

        /*
         * 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 meta_write_pointer;
};

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

static inline bool btrfs_is_block_group_data_only(
                                        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);
}

#ifdef CONFIG_BTRFS_DEBUG
static inline int btrfs_should_fragment_free_space(
                struct btrfs_block_group *block_group)
{
        struct btrfs_fs_info *fs_info = block_group->fs_info;

        return (btrfs_test_opt(fs_info, FRAGMENT_METADATA) &&
                block_group->flags & BTRFS_BLOCK_GROUP_METADATA) ||
               (btrfs_test_opt(fs_info, FRAGMENT_DATA) &&
                block_group->flags &  BTRFS_BLOCK_GROUP_DATA);
}
#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);
bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr);
void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr);
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_wait_block_group_cache_done(struct btrfs_block_group *cache);
int btrfs_cache_block_group(struct btrfs_block_group *cache,
                            int load_cache_only);
void btrfs_put_caching_control(struct btrfs_caching_control *ctl);
struct btrfs_caching_control *btrfs_get_caching_control(
                struct btrfs_block_group *cache);
u64 add_new_free_space(struct btrfs_block_group *block_group,
                       u64 start, u64 end);
struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
                                struct btrfs_fs_info *fs_info,
                                const u64 chunk_offset);
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
                             u64 group_start, struct extent_map *em);
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,
                                                 u64 bytes_used, 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, int alloc);
int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
                             u64 ram_bytes, u64 num_bytes, int delalloc);
void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
                               u64 num_bytes, int delalloc);
int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, 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);
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);
void btrfs_wait_space_cache_v1_finished(struct btrfs_block_group *cache,
                                struct btrfs_caching_control *caching_ctl);
int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
                       struct block_device *bdev, 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(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);

#endif /* BTRFS_BLOCK_GROUP_H */