f2fs: add on-disk layout

/**

 * include/linux/f2fs_fs.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.

 */

#ifndef _LINUX_F2FS_FS_H

#define _LINUX_F2FS_FS_H

#include <linux/pagemap.h>

#include <linux/types.h>

#define F2FS_SUPER_OFFSET		1024	/* byte-size offset */

#define F2FS_LOG_SECTOR_SIZE		9	/* 9 bits for 512 byte */

#define F2FS_LOG_SECTORS_PER_BLOCK	3	/* 4KB: F2FS_BLKSIZE */

#define F2FS_BLKSIZE			4096	/* support only 4KB block */

#define F2FS_MAX_EXTENSION		64	/* # of extension entries */

#define NULL_ADDR		0x0U

#define NEW_ADDR		-1U

#define F2FS_ROOT_INO(sbi)	(sbi->root_ino_num)

#define F2FS_NODE_INO(sbi)	(sbi->node_ino_num)

#define F2FS_META_INO(sbi)	(sbi->meta_ino_num)

/* This flag is used by node and meta inodes, and by recovery */

#define GFP_F2FS_ZERO	(GFP_NOFS | __GFP_ZERO)

/*

 * For further optimization on multi-head logs, on-disk layout supports maximum

 * 16 logs by default. The number, 16, is expected to cover all the cases

 * enoughly. The implementaion currently uses no more than 6 logs.

 * Half the logs are used for nodes, and the other half are used for data.

 */

#define MAX_ACTIVE_LOGS	16

#define MAX_ACTIVE_NODE_LOGS	8

#define MAX_ACTIVE_DATA_LOGS	8

/*

 * For superblock

 */

struct f2fs_super_block {

	__le32 magic;			/* Magic Number */

	__le16 major_ver;		/* Major Version */

	__le16 minor_ver;		/* Minor Version */

	__le32 log_sectorsize;		/* log2 sector size in bytes */

	__le32 log_sectors_per_block;	/* log2 # of sectors per block */

	__le32 log_blocksize;		/* log2 block size in bytes */

	__le32 log_blocks_per_seg;	/* log2 # of blocks per segment */

	__le32 segs_per_sec;		/* # of segments per section */

	__le32 secs_per_zone;		/* # of sections per zone */

	__le32 checksum_offset;		/* checksum offset inside super block */

	__le64 block_count;		/* total # of user blocks */

	__le32 section_count;		/* total # of sections */

	__le32 segment_count;		/* total # of segments */

	__le32 segment_count_ckpt;	/* # of segments for checkpoint */

	__le32 segment_count_sit;	/* # of segments for SIT */

	__le32 segment_count_nat;	/* # of segments for NAT */

	__le32 segment_count_ssa;	/* # of segments for SSA */

	__le32 segment_count_main;	/* # of segments for main area */

	__le32 segment0_blkaddr;	/* start block address of segment 0 */

	__le32 cp_blkaddr;		/* start block address of checkpoint */

	__le32 sit_blkaddr;		/* start block address of SIT */

	__le32 nat_blkaddr;		/* start block address of NAT */

	__le32 ssa_blkaddr;		/* start block address of SSA */

	__le32 main_blkaddr;		/* start block address of main area */

	__le32 root_ino;		/* root inode number */

	__le32 node_ino;		/* node inode number */

	__le32 meta_ino;		/* meta inode number */

	__u8 uuid[16];			/* 128-bit uuid for volume */

	__le16 volume_name[512];	/* volume name */

	__le32 extension_count;		/* # of extensions below */

	__u8 extension_list[F2FS_MAX_EXTENSION][8];	/* extension array */

} __packed;

/*

 * For checkpoint

 */

#define CP_ERROR_FLAG		0x00000008

#define CP_COMPACT_SUM_FLAG	0x00000004

#define CP_ORPHAN_PRESENT_FLAG	0x00000002

#define CP_UMOUNT_FLAG		0x00000001

struct f2fs_checkpoint {

	__le64 checkpoint_ver;		/* checkpoint block version number */

	__le64 user_block_count;	/* # of user blocks */

	__le64 valid_block_count;	/* # of valid blocks in main area */

	__le32 rsvd_segment_count;	/* # of reserved segments for gc */

	__le32 overprov_segment_count;	/* # of overprovision segments */

	__le32 free_segment_count;	/* # of free segments in main area */

	/* information of current node segments */

	__le32 cur_node_segno[MAX_ACTIVE_NODE_LOGS];

	__le16 cur_node_blkoff[MAX_ACTIVE_NODE_LOGS];

	/* information of current data segments */

	__le32 cur_data_segno[MAX_ACTIVE_DATA_LOGS];

	__le16 cur_data_blkoff[MAX_ACTIVE_DATA_LOGS];

	__le32 ckpt_flags;		/* Flags : umount and journal_present */

	__le32 cp_pack_total_block_count;	/* total # of one cp pack */

	__le32 cp_pack_start_sum;	/* start block number of data summary */

	__le32 valid_node_count;	/* Total number of valid nodes */

	__le32 valid_inode_count;	/* Total number of valid inodes */

	__le32 next_free_nid;		/* Next free node number */

	__le32 sit_ver_bitmap_bytesize;	/* Default value 64 */

	__le32 nat_ver_bitmap_bytesize; /* Default value 256 */

	__le32 checksum_offset;		/* checksum offset inside cp block */

	__le64 elapsed_time;		/* mounted time */

	/* allocation type of current segment */

	unsigned char alloc_type[MAX_ACTIVE_LOGS];

	/* SIT and NAT version bitmap */

	unsigned char sit_nat_version_bitmap[1];

} __packed;

/*

 * For orphan inode management

 */

#define F2FS_ORPHANS_PER_BLOCK	1020

struct f2fs_orphan_block {

	__le32 ino[F2FS_ORPHANS_PER_BLOCK];	/* inode numbers */

	__le32 reserved;	/* reserved */

	__le16 blk_addr;	/* block index in current CP */

	__le16 blk_count;	/* Number of orphan inode blocks in CP */

	__le32 entry_count;	/* Total number of orphan nodes in current CP */

	__le32 check_sum;	/* CRC32 for orphan inode block */

} __packed;

/*

 * For NODE structure

 */

struct f2fs_extent {

	__le32 fofs;		/* start file offset of the extent */

	__le32 blk_addr;	/* start block address of the extent */

	__le32 len;		/* lengh of the extent */

} __packed;

#define F2FS_MAX_NAME_LEN	256

#define ADDRS_PER_INODE         923	/* Address Pointers in an Inode */

#define ADDRS_PER_BLOCK         1018	/* Address Pointers in a Direct Block */

#define NIDS_PER_BLOCK          1018	/* Node IDs in an Indirect Block */

struct f2fs_inode {

	__le16 i_mode;			/* file mode */

	__u8 i_advise;			/* file hints */

	__u8 i_reserved;		/* reserved */

	__le32 i_uid;			/* user ID */

	__le32 i_gid;			/* group ID */

	__le32 i_links;			/* links count */

	__le64 i_size;			/* file size in bytes */

	__le64 i_blocks;		/* file size in blocks */

	__le64 i_atime;			/* access time */

	__le64 i_ctime;			/* change time */

	__le64 i_mtime;			/* modification time */

	__le32 i_atime_nsec;		/* access time in nano scale */

	__le32 i_ctime_nsec;		/* change time in nano scale */

	__le32 i_mtime_nsec;		/* modification time in nano scale */

	__le32 i_generation;		/* file version (for NFS) */

	__le32 i_current_depth;		/* only for directory depth */

	__le32 i_xattr_nid;		/* nid to save xattr */

	__le32 i_flags;			/* file attributes */

	__le32 i_pino;			/* parent inode number */

	__le32 i_namelen;		/* file name length */

	__u8 i_name[F2FS_MAX_NAME_LEN];	/* file name for SPOR */

	struct f2fs_extent i_ext;	/* caching a largest extent */

	__le32 i_addr[ADDRS_PER_INODE];	/* Pointers to data blocks */

	__le32 i_nid[5];		/* direct(2), indirect(2),

						double_indirect(1) node id */

} __packed;

struct direct_node {

	__le32 addr[ADDRS_PER_BLOCK];	/* array of data block address */

} __packed;

struct indirect_node {

	__le32 nid[NIDS_PER_BLOCK];	/* array of data block address */

} __packed;

enum {

	COLD_BIT_SHIFT = 0,

	FSYNC_BIT_SHIFT,

	DENT_BIT_SHIFT,

	OFFSET_BIT_SHIFT

};

struct node_footer {

	__le32 nid;		/* node id */

	__le32 ino;		/* inode nunmber */

	__le32 flag;		/* include cold/fsync/dentry marks and offset */

	__le64 cp_ver;		/* checkpoint version */

	__le32 next_blkaddr;	/* next node page block address */

} __packed;

struct f2fs_node {

	/* can be one of three types: inode, direct, and indirect types */

	union {

		struct f2fs_inode i;

		struct direct_node dn;

		struct indirect_node in;

	};

	struct node_footer footer;

} __packed;

/*

 * For NAT entries

 */

#define NAT_ENTRY_PER_BLOCK (PAGE_CACHE_SIZE / sizeof(struct f2fs_nat_entry))

struct f2fs_nat_entry {

	__u8 version;		/* latest version of cached nat entry */

	__le32 ino;		/* inode number */

	__le32 block_addr;	/* block address */

} __packed;

struct f2fs_nat_block {

	struct f2fs_nat_entry entries[NAT_ENTRY_PER_BLOCK];

} __packed;

/*

 * For SIT entries

 *

 * Each segment is 2MB in size by default so that a bitmap for validity of

 * there-in blocks should occupy 64 bytes, 512 bits.

 * Not allow to change this.

 */

#define SIT_VBLOCK_MAP_SIZE 64

#define SIT_ENTRY_PER_BLOCK (PAGE_CACHE_SIZE / sizeof(struct f2fs_sit_entry))

/*

 * Note that f2fs_sit_entry->vblocks has the following bit-field information.

 * [15:10] : allocation type such as CURSEG_XXXX_TYPE

 * [9:0] : valid block count

 */

#define SIT_VBLOCKS_SHIFT	10

#define SIT_VBLOCKS_MASK	((1 << SIT_VBLOCKS_SHIFT) - 1)

#define GET_SIT_VBLOCKS(raw_sit)				\

	(le16_to_cpu((raw_sit)->vblocks) & SIT_VBLOCKS_MASK)

#define GET_SIT_TYPE(raw_sit)					\

	((le16_to_cpu((raw_sit)->vblocks) & ~SIT_VBLOCKS_MASK)	\

	 >> SIT_VBLOCKS_SHIFT)

struct f2fs_sit_entry {

	__le16 vblocks;				/* reference above */

	__u8 valid_map[SIT_VBLOCK_MAP_SIZE];	/* bitmap for valid blocks */

	__le64 mtime;				/* segment age for cleaning */

} __packed;

struct f2fs_sit_block {

	struct f2fs_sit_entry entries[SIT_ENTRY_PER_BLOCK];

} __packed;

/*

 * For segment summary

 *

 * One summary block contains exactly 512 summary entries, which represents

 * exactly 2MB segment by default. Not allow to change the basic units.

 *

 * NOTE: For initializing fields, you must use set_summary

 *

 * - If data page, nid represents dnode's nid

 * - If node page, nid represents the node page's nid.

 *

 * The ofs_in_node is used by only data page. It represents offset

 * from node's page's beginning to get a data block address.

 * ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)

 */

#define ENTRIES_IN_SUM		512

#define	SUMMARY_SIZE		(sizeof(struct f2fs_summary))

#define	SUM_FOOTER_SIZE		(sizeof(struct summary_footer))

#define SUM_ENTRY_SIZE		(SUMMARY_SIZE * ENTRIES_IN_SUM)

/* a summary entry for a 4KB-sized block in a segment */

struct f2fs_summary {

	__le32 nid;		/* parent node id */

	union {

		__u8 reserved[3];

		struct {

			__u8 version;		/* node version number */

			__le16 ofs_in_node;	/* block index in parent node */

		} __packed;

	};

} __packed;

/* summary block type, node or data, is stored to the summary_footer */

#define SUM_TYPE_NODE		(1)

#define SUM_TYPE_DATA		(0)

struct summary_footer {

	unsigned char entry_type;	/* SUM_TYPE_XXX */

	__u32 check_sum;		/* summary checksum */

} __packed;

#define SUM_JOURNAL_SIZE	(PAGE_CACHE_SIZE - SUM_FOOTER_SIZE -\

				SUM_ENTRY_SIZE)

#define NAT_JOURNAL_ENTRIES	((SUM_JOURNAL_SIZE - 2) /\

				sizeof(struct nat_journal_entry))

#define NAT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\

				sizeof(struct nat_journal_entry))

#define SIT_JOURNAL_ENTRIES	((SUM_JOURNAL_SIZE - 2) /\

				sizeof(struct sit_journal_entry))

#define SIT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\

				sizeof(struct sit_journal_entry))

/*

 * frequently updated NAT/SIT entries can be stored in the spare area in

 * summary blocks

 */

enum {

	NAT_JOURNAL = 0,

	SIT_JOURNAL

};

struct nat_journal_entry {

	__le32 nid;

	struct f2fs_nat_entry ne;

} __packed;

struct nat_journal {

	struct nat_journal_entry entries[NAT_JOURNAL_ENTRIES];

	__u8 reserved[NAT_JOURNAL_RESERVED];

} __packed;

struct sit_journal_entry {

	__le32 segno;

	struct f2fs_sit_entry se;

} __packed;

struct sit_journal {

	struct sit_journal_entry entries[SIT_JOURNAL_ENTRIES];

	__u8 reserved[SIT_JOURNAL_RESERVED];

} __packed;

/* 4KB-sized summary block structure */

struct f2fs_summary_block {

	struct f2fs_summary entries[ENTRIES_IN_SUM];

	union {

		__le16 n_nats;

		__le16 n_sits;

	};

	/* spare area is used by NAT or SIT journals */

	union {

		struct nat_journal nat_j;

		struct sit_journal sit_j;

	};

	struct summary_footer footer;

} __packed;

/*

 * For directory operations

 */

#define F2FS_DOT_HASH		0

#define F2FS_DDOT_HASH		F2FS_DOT_HASH

#define F2FS_MAX_HASH		(~((0x3ULL) << 62))

#define F2FS_HASH_COL_BIT	((0x1ULL) << 63)

typedef __le32	f2fs_hash_t;

/* One directory entry slot covers 8bytes-long file name */

#define F2FS_NAME_LEN		8

/* the number of dentry in a block */

#define NR_DENTRY_IN_BLOCK	214

/* MAX level for dir lookup */

#define MAX_DIR_HASH_DEPTH	63

#define SIZE_OF_DIR_ENTRY	11	/* by byte */

#define SIZE_OF_DENTRY_BITMAP	((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \

					BITS_PER_BYTE)

#define SIZE_OF_RESERVED	(PAGE_SIZE - ((SIZE_OF_DIR_ENTRY + \

				F2FS_NAME_LEN) * \

				NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))

/* One directory entry slot representing F2FS_NAME_LEN-sized file name */

struct f2fs_dir_entry {

	__le32 hash_code;	/* hash code of file name */

	__le32 ino;		/* inode number */

	__le16 name_len;	/* lengh of file name */

	__u8 file_type;		/* file type */

} __packed;

/* 4KB-sized directory entry block */

struct f2fs_dentry_block {

	/* validity bitmap for directory entries in each block */

	__u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];

	__u8 reserved[SIZE_OF_RESERVED];

	struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];

	__u8 filename[NR_DENTRY_IN_BLOCK][F2FS_NAME_LEN];

} __packed;

/* file types used in inode_info->flags */

enum {

	F2FS_FT_UNKNOWN,

	F2FS_FT_REG_FILE,

	F2FS_FT_DIR,

	F2FS_FT_CHRDEV,

	F2FS_FT_BLKDEV,

	F2FS_FT_FIFO,

	F2FS_FT_SOCK,

	F2FS_FT_SYMLINK,

	F2FS_FT_MAX

};

#endif  /* _LINUX_F2FS_FS_H */