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

#ifndef BTRFS_EXTENT_IO_H
#define BTRFS_EXTENT_IO_H

#include <linux/rbtree.h>
#include <linux/refcount.h>
#include <linux/fiemap.h>
#include <linux/btrfs_tree.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/rwsem.h>
#include <linux/list.h>
#include <linux/slab.h>
#include "messages.h"
#include "ulist.h"
#include "misc.h"

struct page;
struct file;
struct folio;
struct inode;
struct fiemap_extent_info;
struct readahead_control;
struct address_space;
struct writeback_control;
struct extent_io_tree;
struct extent_map_tree;
struct extent_state;
struct btrfs_block_group;
struct btrfs_fs_info;
struct btrfs_inode;
struct btrfs_root;
struct btrfs_trans_handle;
struct btrfs_tree_parent_check;

enum {
        EXTENT_BUFFER_UPTODATE,
        EXTENT_BUFFER_DIRTY,
        EXTENT_BUFFER_TREE_REF,
        EXTENT_BUFFER_STALE,
        EXTENT_BUFFER_WRITEBACK,
        EXTENT_BUFFER_UNMAPPED,
        /* write IO error */
        EXTENT_BUFFER_WRITE_ERR,
        /* Indicate the extent buffer is written zeroed out (for zoned) */
        EXTENT_BUFFER_ZONED_ZEROOUT,
        /* Indicate that extent buffer pages a being read */
        EXTENT_BUFFER_READING,
};

/* these are flags for __process_pages_contig */
enum {
        ENUM_BIT(PAGE_UNLOCK),
        /* Page starts writeback, clear dirty bit and set writeback bit */
        ENUM_BIT(PAGE_START_WRITEBACK),
        ENUM_BIT(PAGE_END_WRITEBACK),
        ENUM_BIT(PAGE_SET_ORDERED),
};

/*
 * Folio private values.  Every page that is controlled by the extent map has
 * folio private set to this value.
 */
#define EXTENT_FOLIO_PRIVATE                    1

/*
 * The extent buffer bitmap operations are done with byte granularity instead of
 * word granularity for two reasons:
 * 1. The bitmaps must be little-endian on disk.
 * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
 *    single word in a bitmap may straddle two pages in the extent buffer.
 */
#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
#define BYTE_MASK ((1U << BITS_PER_BYTE) - 1)
#define BITMAP_FIRST_BYTE_MASK(start) \
        ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
#define BITMAP_LAST_BYTE_MASK(nbits) \
        (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))


int __init extent_buffer_init_cachep(void);
void __cold extent_buffer_free_cachep(void);

#define INLINE_EXTENT_BUFFER_PAGES     (BTRFS_MAX_METADATA_BLOCKSIZE / PAGE_SIZE)
struct extent_buffer {
        u64 start;
        u32 len;
        u32 folio_size;
        unsigned long bflags;
        struct btrfs_fs_info *fs_info;

        /*
         * The address where the eb can be accessed without any cross-page handling.
         * This can be NULL if not possible.
         */
        void *addr;

        spinlock_t refs_lock;
        refcount_t refs;
        int read_mirror;
        /* >= 0 if eb belongs to a log tree, -1 otherwise */
        s8 log_index;
        u8 folio_shift;
        struct rcu_head rcu_head;

        struct rw_semaphore lock;

        /*
         * Pointers to all the folios of the extent buffer.
         *
         * For now the folio is always order 0 (aka, a single page).
         */
        struct folio *folios[INLINE_EXTENT_BUFFER_PAGES];
#ifdef CONFIG_BTRFS_DEBUG
        struct list_head leak_list;
        pid_t lock_owner;
#endif
};

struct btrfs_eb_write_context {
        struct writeback_control *wbc;
        struct extent_buffer *eb;
        /* Block group @eb resides in. Only used for zoned mode. */
        struct btrfs_block_group *zoned_bg;
};

static inline unsigned long offset_in_eb_folio(const struct extent_buffer *eb,
                                               u64 start)
{
        ASSERT(eb->folio_size);
        return start & (eb->folio_size - 1);
}

/*
 * Get the correct offset inside the page of extent buffer.
 *
 * @eb:         target extent buffer
 * @start:      offset inside the extent buffer
 *
 * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.
 */
static inline size_t get_eb_offset_in_folio(const struct extent_buffer *eb,
                                            unsigned long offset)
{
        /*
         * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
         *    1.1) One large folio covering the whole eb
         *         The eb->start is aligned to folio size, thus adding it
         *         won't cause any difference.
         *    1.2) Several page sized folios
         *         The eb->start is aligned to folio (page) size, thus
         *         adding it won't cause any difference.
         *
         * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
         *    In this case there would only be one page sized folio, and there
         *    may be several different extent buffers in the page/folio.
         *    We need to add eb->start to properly access the offset inside
         *    that eb.
         */
        return offset_in_folio(eb->folios[0], offset + eb->start);
}

static inline unsigned long get_eb_folio_index(const struct extent_buffer *eb,
                                               unsigned long offset)
{
        /*
         * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
         *    1.1) One large folio covering the whole eb.
         *         the folio_shift would be large enough to always make us
         *         return 0 as index.
         *    1.2) Several page sized folios
         *         The folio_shift would be PAGE_SHIFT, giving us the correct
         *         index.
         *
         * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
         *    The folio would only be page sized, and always give us 0 as index.
         */
        return offset >> eb->folio_shift;
}

/*
 * Structure to record how many bytes and which ranges are set/cleared
 */
struct extent_changeset {
        /* How many bytes are set/cleared in this operation */
        u64 bytes_changed;

        /* Changed ranges */
        struct ulist range_changed;
};

static inline void extent_changeset_init(struct extent_changeset *changeset)
{
        changeset->bytes_changed = 0;
        ulist_init(&changeset->range_changed);
}

static inline struct extent_changeset *extent_changeset_alloc(void)
{
        struct extent_changeset *ret;

        ret = kmalloc_obj(*ret);
        if (!ret)
                return NULL;

        extent_changeset_init(ret);
        return ret;
}

static inline void extent_changeset_prealloc(struct extent_changeset *changeset, gfp_t gfp_mask)
{
        ulist_prealloc(&changeset->range_changed, gfp_mask);
}

static inline void extent_changeset_release(struct extent_changeset *changeset)
{
        if (!changeset)
                return;
        changeset->bytes_changed = 0;
        ulist_release(&changeset->range_changed);
}

static inline void extent_changeset_free(struct extent_changeset *changeset)
{
        if (!changeset)
                return;
        extent_changeset_release(changeset);
        kfree(changeset);
}

bool try_release_extent_mapping(struct folio *folio, gfp_t mask);
int try_release_extent_buffer(struct folio *folio);

int btrfs_read_folio(struct file *file, struct folio *folio);
void extent_write_locked_range(struct inode *inode, const struct folio *locked_folio,
                               u64 start, u64 end, struct writeback_control *wbc,
                               bool pages_dirty);
int btrfs_writepages(struct address_space *mapping, struct writeback_control *wbc);
int btree_writepages(struct address_space *mapping, struct writeback_control *wbc);
void btrfs_btree_wait_writeback_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
void btrfs_readahead(struct readahead_control *rac);
int set_folio_extent_mapped(struct folio *folio);
void clear_folio_extent_mapped(struct folio *folio);

struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
                                          u64 start, u64 owner_root, int level);
struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
                                                u64 start);
struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src);
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
                                         u64 start);
void free_extent_buffer(struct extent_buffer *eb);
void free_extent_buffer_stale(struct extent_buffer *eb);
int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
                             const struct btrfs_tree_parent_check *parent_check);
int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
                                    const struct btrfs_tree_parent_check *parent_check);

static inline void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
{
        wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
                       TASK_UNINTERRUPTIBLE);
}

void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
                                u64 bytenr, u64 owner_root, u64 gen, int level);
void btrfs_readahead_node_child(struct extent_buffer *node, int slot);

/* Note: this can be used in for loops without caching the value in a variable. */
static inline int __pure num_extent_pages(const struct extent_buffer *eb)
{
        /*
         * For sectorsize == PAGE_SIZE case, since nodesize is always aligned to
         * sectorsize, it's just eb->len >> PAGE_SHIFT.
         *
         * For sectorsize < PAGE_SIZE case, we could have nodesize < PAGE_SIZE,
         * thus have to ensure we get at least one page.
         */
        return (eb->len >> PAGE_SHIFT) ?: 1;
}

/*
 * This can only be determined at runtime by checking eb::folios[0].
 *
 * As we can have either one large folio covering the whole eb
 * (either nodesize <= PAGE_SIZE, or high order folio), or multiple
 * single-paged folios.
 *
 * Note: this can be used in for loops without caching the value in a variable.
 */
static inline int __pure num_extent_folios(const struct extent_buffer *eb)
{
        if (!eb->folios[0])
                return 0;
        if (folio_order(eb->folios[0]))
                return 1;
        return num_extent_pages(eb);
}

static inline int extent_buffer_uptodate(const struct extent_buffer *eb)
{
        return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
}

int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
                         unsigned long start, unsigned long len);
void read_extent_buffer(const struct extent_buffer *eb, void *dst,
                        unsigned long start,
                        unsigned long len);
int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
                                       void __user *dst, unsigned long start,
                                       unsigned long len);
void write_extent_buffer(const struct extent_buffer *eb, const void *src,
                         unsigned long start, unsigned long len);

static inline void write_extent_buffer_chunk_tree_uuid(
                const struct extent_buffer *eb, const void *chunk_tree_uuid)
{
        write_extent_buffer(eb, chunk_tree_uuid,
                            offsetof(struct btrfs_header, chunk_tree_uuid),
                            BTRFS_FSID_SIZE);
}

static inline void write_extent_buffer_fsid(const struct extent_buffer *eb,
                                            const void *fsid)
{
        write_extent_buffer(eb, fsid, offsetof(struct btrfs_header, fsid),
                            BTRFS_FSID_SIZE);
}

void copy_extent_buffer_full(const struct extent_buffer *dst,
                             const struct extent_buffer *src);
void copy_extent_buffer(const struct extent_buffer *dst,
                        const struct extent_buffer *src,
                        unsigned long dst_offset, unsigned long src_offset,
                        unsigned long len);
void memcpy_extent_buffer(const struct extent_buffer *dst,
                          unsigned long dst_offset, unsigned long src_offset,
                          unsigned long len);
void memmove_extent_buffer(const struct extent_buffer *dst,
                           unsigned long dst_offset, unsigned long src_offset,
                           unsigned long len);
void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
                           unsigned long len);
bool extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
                            unsigned long pos);
void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
                              unsigned long pos, unsigned long len);
void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
                                unsigned long start, unsigned long pos,
                                unsigned long len);
void set_extent_buffer_dirty(struct extent_buffer *eb);
void set_extent_buffer_uptodate(struct extent_buffer *eb);
void clear_extent_buffer_uptodate(struct extent_buffer *eb);
void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
                                  const struct folio *locked_folio,
                                  struct extent_state **cached,
                                  u32 bits_to_clear, unsigned long page_ops);
int extent_invalidate_folio(struct extent_io_tree *tree,
                            struct folio *folio, size_t offset);
void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
                              struct extent_buffer *buf);

int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array,
                           bool nofail);
int btrfs_alloc_folio_array(unsigned int nr_folios, unsigned int order,
                            struct folio **folio_array);

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
bool find_lock_delalloc_range(struct inode *inode,
                              struct folio *locked_folio, u64 *start,
                             u64 *end);
#endif
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
                                               u64 start);

#ifdef CONFIG_BTRFS_DEBUG
void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info);
#else
#define btrfs_extent_buffer_leak_debug_check(fs_info)   do {} while (0)
#endif

#endif