path: root/fs/ext4/ext4.h

/*
 *  ext4.h
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/include/linux/minix_fs.h
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#ifndef _EXT4_H
#define _EXT4_H

#include <linux/types.h>
#include <linux/blkdev.h>
#include <linux/magic.h>
#include <linux/jbd2.h>
#include <linux/quota.h>
#include "ext4_i.h"

/*
 * The fourth extended filesystem constants/structures
 */

/*
 * Define EXT4FS_DEBUG to produce debug messages
 */
#undef EXT4FS_DEBUG

/*
 * Define EXT4_RESERVATION to reserve data blocks for expanding files
 */
#define EXT4_DEFAULT_RESERVE_BLOCKS	8
/*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
#define EXT4_MAX_RESERVE_BLOCKS		1027
#define EXT4_RESERVE_WINDOW_NOT_ALLOCATED 0

/*
 * Debug code
 */
#ifdef EXT4FS_DEBUG
#define ext4_debug(f, a...)						\
	do {								\
		printk(KERN_DEBUG "EXT4-fs DEBUG (%s, %d): %s:",	\
			__FILE__, __LINE__, __func__);			\
		printk(KERN_DEBUG f, ## a);				\
	} while (0)
#else
#define ext4_debug(f, a...)	do {} while (0)
#endif

#define EXT4_MULTIBLOCK_ALLOCATOR	1

/* prefer goal again. length */
#define EXT4_MB_HINT_MERGE		1
/* blocks already reserved */
#define EXT4_MB_HINT_RESERVED		2
/* metadata is being allocated */
#define EXT4_MB_HINT_METADATA		4
/* first blocks in the file */
#define EXT4_MB_HINT_FIRST		8
/* search for the best chunk */
#define EXT4_MB_HINT_BEST		16
/* data is being allocated */
#define EXT4_MB_HINT_DATA		32
/* don't preallocate (for tails) */
#define EXT4_MB_HINT_NOPREALLOC		64
/* allocate for locality group */
#define EXT4_MB_HINT_GROUP_ALLOC	128
/* allocate goal blocks or none */
#define EXT4_MB_HINT_GOAL_ONLY		256
/* goal is meaningful */
#define EXT4_MB_HINT_TRY_GOAL		512
/* blocks already pre-reserved by delayed allocation */
#define EXT4_MB_DELALLOC_RESERVED      1024


struct ext4_allocation_request {
	/* target inode for block we're allocating */
	struct inode *inode;
	/* logical block in target inode */
	ext4_lblk_t logical;
	/* phys. target (a hint) */
	ext4_fsblk_t goal;
	/* the closest logical allocated block to the left */
	ext4_lblk_t lleft;
	/* phys. block for ^^^ */
	ext4_fsblk_t pleft;
	/* the closest logical allocated block to the right */
	ext4_lblk_t lright;
	/* phys. block for ^^^ */
	ext4_fsblk_t pright;
	/* how many blocks we want to allocate */
	unsigned int len;
	/* flags. see above EXT4_MB_HINT_* */
	unsigned int flags;
};

/*
 * Special inodes numbers
 */
#define	EXT4_BAD_INO		 1	/* Bad blocks inode */
#define EXT4_ROOT_INO		 2	/* Root inode */
#define EXT4_BOOT_LOADER_INO	 5	/* Boot loader inode */
#define EXT4_UNDEL_DIR_INO	 6	/* Undelete directory inode */
#define EXT4_RESIZE_INO		 7	/* Reserved group descriptors inode */
#define EXT4_JOURNAL_INO	 8	/* Journal inode */

/* First non-reserved inode for old ext4 filesystems */
#define EXT4_GOOD_OLD_FIRST_INO	11

/*
 * Maximal count of links to a file
 */
#define EXT4_LINK_MAX		65000

/*
 * Macro-instructions used to manage several block sizes
 */
#define EXT4_MIN_BLOCK_SIZE		1024
#define	EXT4_MAX_BLOCK_SIZE		65536
#define EXT4_MIN_BLOCK_LOG_SIZE		10
#ifdef __KERNEL__
# define EXT4_BLOCK_SIZE(s)		((s)->s_blocksize)
#else
# define EXT4_BLOCK_SIZE(s)		(EXT4_MIN_BLOCK_SIZE << (s)->s_log_block_size)
#endif
#define	EXT4_ADDR_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / sizeof(__u32))
#ifdef __KERNEL__
# define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
#else
# define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
#endif
#ifdef __KERNEL__
#define	EXT4_ADDR_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_addr_per_block_bits)
#define EXT4_INODE_SIZE(s)		(EXT4_SB(s)->s_inode_size)
#define EXT4_FIRST_INO(s)		(EXT4_SB(s)->s_first_ino)
#else
#define EXT4_INODE_SIZE(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
				 EXT4_GOOD_OLD_INODE_SIZE : \
				 (s)->s_inode_size)
#define EXT4_FIRST_INO(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
				 EXT4_GOOD_OLD_FIRST_INO : \
				 (s)->s_first_ino)
#endif
#define EXT4_BLOCK_ALIGN(size, blkbits)		ALIGN((size), (1 << (blkbits)))

/*
 * Structure of a block