/*
 * fs/f2fs/node.h
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *             http://www.samsung.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
/* start node id of a node block dedicated to the given node id */
#define START_NID(nid) ((nid / NAT_ENTRY_PER_BLOCK) * NAT_ENTRY_PER_BLOCK)

/* node block offset on the NAT area dedicated to the given start node id */
#define NAT_BLOCK_OFFSET(start_nid) (start_nid / NAT_ENTRY_PER_BLOCK)

/* # of pages to perform synchronous readahead before building free nids */
#define FREE_NID_PAGES  8
#define MAX_FREE_NIDS   (NAT_ENTRY_PER_BLOCK * FREE_NID_PAGES)

#define DEF_RA_NID_PAGES        0       /* # of nid pages to be readaheaded */

/* maximum readahead size for node during getting data blocks */
#define MAX_RA_NODE             128

/* control the memory footprint threshold (10MB per 1GB ram) */
#define DEF_RAM_THRESHOLD       1

/* control dirty nats ratio threshold (default: 10% over max nid count) */
#define DEF_DIRTY_NAT_RATIO_THRESHOLD           10
/* control total # of nats */
#define DEF_NAT_CACHE_THRESHOLD                 100000

/* vector size for gang look-up from nat cache that consists of radix tree */
#define NATVEC_SIZE     64
#define SETVEC_SIZE     32

/* return value for read_node_page */
#define LOCKED_PAGE     1

/* For flag in struct node_info */
enum {
        IS_CHECKPOINTED,        /* is it checkpointed before? */
        HAS_FSYNCED_INODE,      /* is the inode fsynced before? */
        HAS_LAST_FSYNC,         /* has the latest node fsync mark? */
        IS_DIRTY,               /* this nat entry is dirty? */
};

/*
 * For node information
 */
struct node_info {
        nid_t nid;              /* node id */
        nid_t ino;              /* inode number of the node's owner */
        block_t blk_addr;       /* block address of the node */
        unsigned char version;  /* version of the node */
        unsigned char flag;     /* for node information bits */
};

struct nat_entry {
        struct list_head list;  /* for clean or dirty nat list */
        struct node_info ni;    /* in-memory node information */
};

#define nat_get_nid(nat)                (nat->ni.nid)
#define nat_set_nid(nat, n)             (nat->ni.nid = n)
#define nat_get_blkaddr(nat)            (nat->ni.blk_addr)
#define nat_set_blkaddr(nat, b)         (nat->ni.blk_addr = b)
#define nat_get_ino(nat)                (nat->ni.ino)
#define nat_set_ino(nat, i)             (nat->ni.ino = i)
#define nat_get_version(nat)            (nat->ni.version)
#define nat_set_version(nat, v)         (nat->ni.version = v)

#define inc_node_version(version)       (++version)

static inline void copy_node_info(struct node_info *dst,
                                                struct node_info *src)
{
        dst->nid = src->nid;
        dst->ino = src->ino;
        dst->blk_addr = src->blk_addr;
        dst->version = src->version;
        /* should not copy flag here */
}

static inline void set_nat_flag(struct nat_entry *ne,
                                unsigned int type, bool set)
{
        unsigned char mask = 0x01 << type;
        if (set)
                ne->ni.flag |= mask;
        else
                ne->ni.flag &= ~mask;
}

static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
{
        unsigned char mask = 0x01 << type;
        return ne->ni.flag & mask;
}

static inline void nat_reset_flag(struct nat_entry *ne)
{
        /* these states can be set only after checkpoint was done */
        set_nat_flag(ne, IS_CHECKPOINTED, true);
        set_nat_flag(ne, HAS_FSYNCED_INODE, false);
        set_nat_flag(ne, HAS_LAST_FSYNC, true);
}

static inline void node_info_from_raw_nat(struct node_info *ni,
                                                struct f2fs_nat_entry *raw_ne)
{
        ni->ino = le32_to_cpu(raw_ne->ino);
        ni->blk_addr = le32_to_cpu(raw_ne->block_addr);
        ni->version = raw_ne->version;
}

static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne,
                                                struct node_info *ni)
{
        raw_ne->ino = cpu_to_le32(ni->ino);
        raw_ne->block_addr = cpu_to_le32(ni->blk_addr);
        raw_ne->version = ni->version;
}

static inline bool excess_dirty_nats(struct f2fs_sb_info *sbi)
{
        return NM_I(sbi)->dirty_nat_cnt >= NM_I(sbi)->max_nid *
                                        NM_I(sbi)->dirty_nats_ratio / 100;
}

static inline bool excess_cached_nats(struct f2fs_sb_info *sbi)
{
        return NM_I(sbi)->nat_cnt >= DEF_NAT_CACHE_THRESHOLD;
}

enum mem_type {
        FREE_NIDS,      /* indicates the free nid list */
        NAT_ENTRIES,    /* indicates the cached nat entry */
        DIRTY_DENTS,    /* indicates dirty dentry pages */
        INO_ENTRIES,    /* indicates inode entries */
        EXTENT_CACHE,   /* indicates extent cache */
        BASE_CHECK,     /* check kernel status */
};

struct nat_entry_set {
        struct list_head set_list;      /* link with other nat sets */
        struct list_head entry_list;    /* link with dirty nat entries */
        nid_t set;                      /* set number*/
        unsigned int entry_cnt;         /* the # of nat entries in set */
};

/*
 * For free nid mangement
 */
enum nid_state {
        NID_NEW,        /* newly added to free nid list */
        NID_ALLOC       /* it is allocated */
};

struct free_nid {
        struct list_head list;  /* for free node id list */
        nid_t nid;              /* node id */
        int state;              /* in use or not: NID_NEW or NID_ALLOC */
};

static inline void next_free_nid(struct f2fs_sb_info *sbi, nid_t *nid)
{
        struct f2fs_nm_info *nm_i = NM_I(sbi);
        struct free_nid *fnid;

        spin_lock(&nm_i->nid_list_lock);
        if (nm_i->nid_cnt[FREE_NID_LIST] <= 0) {
                spin_unlock(&nm_i->nid_list_lock);
                return;
        }
        fnid = list_entry(nm_i->nid_list[FREE_NID_LIST].next,
                                                struct free_nid, list);
        *nid = fnid->nid;
        spin_unlock(&nm_i->nid_list_lock);
}

/*
 * inline functions
 */
static inline void get_nat_bitmap(struct f2fs_sb_info *sbi, void *addr)
{
        struct f2fs_nm_info *nm_i = NM_I(sbi);
        memcpy(addr, nm_i->nat_bitmap, nm_i->bitmap_size);
}

static inline pgoff_t current_nat_addr(struct f2fs_sb_info *sbi, nid_t start)
{
        struct f2fs_nm_info *nm_i = NM_I(sbi);
        pgoff_t block_off;
        pgoff_t block_addr;
        int seg_off;

        block_off = NAT_BLOCK_OFFSET(start);
        seg_off = block_off >> sbi->log_blocks_per_seg;

        block_addr = (pgoff_t)(nm_i->nat_blkaddr +
                (seg_off << sbi->log_blocks_per_seg << 1) +
                (block_off & (sbi->blocks_per_seg - 1)));

        if (f2fs_test_bit(block_off, nm_i->nat_bitmap))
                block_addr += sbi->blocks_per_seg;

        return block_addr;
}

static inline pgoff_t next_nat_addr(struct f2fs_sb_info *sbi,
                                                pgoff_t block_addr)
{
        struct f2fs_nm_info *nm_i = NM_I(sbi);

        block_addr -= nm_i->nat_blkaddr;
        if ((block_addr >> sbi->log_blocks_per_seg) % 2)
                block_addr -= sbi->blocks_per_seg;
        else
                block_addr += sbi->blocks_per_seg;

        return block_addr + nm_i->nat_blkaddr;
}

static inline void set_to_next_nat(struct f2fs_nm_info *nm_i, nid_t start_nid)
{
        unsigned int block_off = NAT_BLOCK_OFFSET(start_nid);

        f2fs_change_bit(block_off, nm_i->nat_bitmap);
}

static inline nid_t ino_of_node(struct page *node_page)
{
        struct f2fs_node *rn = F2FS_NODE(node_page);
        return le32_to_cpu(rn->footer.ino);
}

static inline nid_t nid_of_node(struct page *node_page)
{
        struct f2fs_node *rn = F2FS_NODE(node_page);
        return le32_to_cpu(rn->footer.nid);
}

static inline unsigned int ofs_of_node(struct page *node_page)
{
        struct f2fs_node *rn = F2FS_NODE(node_page);
        unsigned flag = le32_to_cpu(rn->footer.flag);
        return flag >> OFFSET_BIT_SHIFT;
}

static inline __u64 cpver_of_node(struct page *node_page)
{
        struct f2fs_node *rn = F2FS_NODE(node_page);
        return le64_to_cpu(rn->footer.cp_ver);
}

static inline block_t next_blkaddr_of_node(struct page *node_page)
{
        struct f2fs_node *rn = F2FS_NODE(node_page);
        return le32_to_cpu(rn->footer.next_blkaddr);
}

static inline void fill_node_footer(struct page *page, nid_t nid,
                                nid_t ino, unsigned int ofs, bool reset)
{
        struct f2fs_node *rn = F2FS_NODE(page);
        unsigned int old_flag = 0;

        if (reset)
                memset(rn, 0, sizeof(*rn));
        else
                old_flag = le32_to_cpu(rn->footer.flag);

        rn->footer.nid = cpu_to_le32(nid);
        rn->footer.ino = cpu_to_le32(ino);

        /* should remain old flag bits such as COLD_BIT_SHIFT */
        rn->footer.flag = cpu_to_le32((ofs << OFFSET_BIT_SHIFT) |
                                        (old_flag & OFFSET_BIT_MASK));
}

static inline void copy_node_footer(struct page *dst, struct page *src)
{
        struct f2fs_node *src_rn = F2FS_NODE(src);
        struct f2fs_node *dst_rn = F2FS_NODE(dst);
        memcpy(&dst_rn->footer, &src_rn->footer, sizeof(struct node_footer));
}

static inline void fill_node_footer_blkaddr(struct page *page, block_t blkaddr)
{
        struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
        struct f2fs_node *rn = F2FS_NODE(page);
        size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
        __u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);

        if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
                __u64 crc = le32_to_cpu(*((__le32 *)
                                ((unsigned char *)ckpt + crc_offset)));
                cp_ver |= (crc << 32);
        }
        rn->footer.cp_ver = cpu_to_le64(cp_ver);
        rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
}

static inline bool is_recoverable_dnode(struct page *page)
{
        struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
        size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
        __u64 cp_ver = cur_cp_version(ckpt);

        if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
                __u64 crc = le32_to_cpu(*((__le32 *)
                                ((unsigned char *)ckpt + crc_offset)));
                cp_ver |= (crc << 32);
        }
        return cp_ver == cpver_of_node(page);
}

/*
 * f2fs assigns the following node offsets described as (num).
 * N = NIDS_PER_BLOCK
 *
 *  Inode block (0)
 *    |- direct node (1)
 *    |- direct node (2)
 *    |- indirect node (3)
 *    |            `- direct node (4 => 4 + N - 1)
 *    |- indirect node (4 + N)
 *    |            `- direct node (5 + N => 5 + 2N - 1)
 *    `- double indirect node (5 + 2N)
 *                 `- indirect node (6 + 2N)
 *                       `- direct node
 *                 ......
 *                 `- indirect node ((6 + 2N) + x(N + 1))
 *                       `- direct node
 *                 ......
 *                 `- indirect node ((6 + 2N) + (N - 1)(N + 1))
 *                       `- direct node
 */
static inline bool IS_DNODE(struct page *node_page)
{
        unsigned int ofs = ofs_of_node(node_page);

        if (f2fs_has_xattr_block(ofs))
                return false;

        if (ofs == 3 || ofs == 4 + NIDS_PER_BLOCK ||
                        ofs == 5 + 2 * NIDS_PER_BLOCK)
                return false;
        if (ofs >= 6 + 2 * NIDS_PER_BLOCK) {
                ofs -= 6 + 2 * NIDS_PER_BLOCK;
                if (!((long int)ofs % (NIDS_PER_BLOCK + 1)))
                        return false;
        }
        return true;
}

static inline int set_nid(struct page *p, int off, nid_t nid, bool i)
{
        struct f2fs_node *rn = F2FS_NODE(p);

        f2fs_wait_on_page_writeback(p, NODE, true);

        if (i)
                rn->i.i_nid[off - NODE_DIR1_BLOCK] = cpu_to_le32(nid);
        else
                rn->in.nid[off] = cpu_to_le32(nid);
        return set_page_dirty(p);
}

static inline nid_t get_nid(struct page *p, int off, bool i)
{
        struct f2fs_node *rn = F2FS_NODE(p);

        if (i)
                return le32_to_cpu(rn->i.i_nid[off - NODE_DIR1_BLOCK]);
        return le32_to_cpu(rn->in.nid[off]);
}

/*
 * Coldness identification:
 *  - Mark cold files in f2fs_inode_info
 *  - Mark cold node blocks in their node footer
 *  - Mark cold data pages in page cache
 */
static inline int is_cold_data(struct page *page)
{
        return PageChecked(page);
}

static inline void set_cold_data(struct page *page)
{
        SetPageChecked(page);
}

static inline void clear_cold_data(struct page *page)
{
        ClearPageChecked(page);
}

static inline int is_node(struct page *page, int type)
{
        struct f2fs_node *rn = F2FS_NODE(page);
        return le32_to_cpu(rn->footer.flag) & (1 << type);
}

#define is_cold_node(page)      is_node(page, COLD_BIT_SHIFT)
#define is_fsync_dnode(page)    is_node(page, FSYNC_BIT_SHIFT)
#define is_dent_dnode(page)     is_node(page, DENT_BIT_SHIFT)

static inline int is_inline_node(struct page *page)
{
        return PageChecked(page);
}

static inline void set_inline_node(struct page *page)
{
        SetPageChecked(page);
}

static inline void clear_inline_node(struct page *page)
{
        ClearPageChecked(page);
}

static inline void set_cold_node(struct inode *inode, struct page *page)
{
        struct f2fs_node *rn = F2FS_NODE(page);
        unsigned int flag = le32_to_cpu(rn->footer.flag);

        if (S_ISDIR(inode->i_mode))
                flag &= ~(0x1 << COLD_BIT_SHIFT);
        else
                flag |= (0x1 << COLD_BIT_SHIFT);
        rn->footer.flag = cpu_to_le32(flag);
}

static inline void set_mark(struct page *page, int mark, int type)
{
        struct f2fs_node *rn = F2FS_NODE(page);
        unsigned int flag = le32_to_cpu(rn->footer.flag);
        if (mark)
                flag |= (0x1 << type);
        else
                flag &= ~(0x1 << type);
        rn->footer.flag = cpu_to_le32(flag);
}
#define set_dentry_mark(page, mark)     set_mark(page, mark, DENT_BIT_SHIFT)
#define set_fsync_mark(page, mark)      set_mark(page, mark, FSYNC_BIT_SHIFT)