include/linux/ext4_fs_extents.h - kernel/msm - Gitiles

 /*
  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
  * Written by Alex Tomas <alex@clusterfs.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.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public Licens
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  */

 #ifndef _LINUX_EXT4_EXTENTS
 #define _LINUX_EXT4_EXTENTS

 #include <linux/ext4_fs.h>

 /*
  * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
  * becomes very small, so index split, in-depth growing and
  * other hard changes happen much more often.
  * This is for debug purposes only.
  */
 #define AGGRESSIVE_TEST_

 /*
  * With EXTENTS_STATS defined, the number of blocks and extents
  * are collected in the truncate path. They'll be shown at
  * umount time.
  */
 #define EXTENTS_STATS__

 /*
  * If CHECK_BINSEARCH is defined, then the results of the binary search
  * will also be checked by linear search.
  */
 #define CHECK_BINSEARCH__

 /*
  * If EXT_DEBUG is defined you can use the 'extdebug' mount option
  * to get lots of info about what's going on.
  */
 #define EXT_DEBUG__
 #ifdef EXT_DEBUG
 #define ext_debug(a...)		printk(a)
 #else
 #define ext_debug(a...)
 #endif

 /*
  * If EXT_STATS is defined then stats numbers are collected.
  * These number will be displayed at umount time.
  */
 #define EXT_STATS_


 /*
  * ext4_inode has i_block array (60 bytes total).
  * The first 12 bytes store ext4_extent_header;
  * the remainder stores an array of ext4_extent.
  */

 /*
  * This is the extent on-disk structure.
  * It's used at the bottom of the tree.
  */
 struct ext4_extent {
 	__le32	ee_block;	/* first logical block extent covers */
 	__le16	ee_len;		/* number of blocks covered by extent */
 	__le16	ee_start_hi;	/* high 16 bits of physical block */
 	__le32	ee_start_lo;	/* low 32 bits of physical block */
 };

 /*
  * This is index on-disk structure.
  * It's used at all the levels except the bottom.
  */
 struct ext4_extent_idx {
 	__le32	ei_block;	/* index covers logical blocks from 'block' */
 	__le32	ei_leaf_lo;	/* pointer to the physical block of the next *
 				 * level. leaf or next index could be there */
 	__le16	ei_leaf_hi;	/* high 16 bits of physical block */
 	__u16	ei_unused;
 };

 /*
  * Each block (leaves and indexes), even inode-stored has header.
  */
 struct ext4_extent_header {
 	__le16	eh_magic;	/* probably will support different formats */
 	__le16	eh_entries;	/* number of valid entries */
 	__le16	eh_max;		/* capacity of store in entries */
 	__le16	eh_depth;	/* has tree real underlying blocks? */
 	__le32	eh_generation;	/* generation of the tree */
 };

 #define EXT4_EXT_MAGIC		cpu_to_le16(0xf30a)

 /*
  * Array of ext4_ext_path contains path to some extent.
  * Creation/lookup routines use it for traversal/splitting/etc.
  * Truncate uses it to simulate recursive walking.
  */
 struct ext4_ext_path {
 	ext4_fsblk_t			p_block;
 	__u16				p_depth;
 	struct ext4_extent		*p_ext;
 	struct ext4_extent_idx		*p_idx;
 	struct ext4_extent_header	*p_hdr;
 	struct buffer_head		*p_bh;
 };

 /*
  * structure for external API
  */

 #define EXT4_EXT_CACHE_NO	0
 #define EXT4_EXT_CACHE_GAP	1
 #define EXT4_EXT_CACHE_EXTENT	2

 /*
  * to be called by ext4_ext_walk_space()
  * negative retcode - error
  * positive retcode - signal for ext4_ext_walk_space(), see below
  * callback must return valid extent (passed or newly created)
  */
 typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *,
 					struct ext4_ext_cache *,
 					void *);

 #define EXT_CONTINUE	0
 #define EXT_BREAK	1
 #define EXT_REPEAT	2


 #define EXT_MAX_BLOCK	0xffffffff

 /*
  * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
  * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
  * MSB of ee_len field in the extent datastructure to signify if this
  * particular extent is an initialized extent or an uninitialized (i.e.
  * preallocated).
  * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
  * uninitialized extent.
  * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
  * uninitialized one. In other words, if MSB of ee_len is set, it is an
  * uninitialized extent with only one special scenario when ee_len = 0x8000.
  * In this case we can not have an uninitialized extent of zero length and
  * thus we make it as a special case of initialized extent with 0x8000 length.
  * This way we get better extent-to-group alignment for initialized extents.
  * Hence, the maximum number of blocks we can have in an *initialized*
  * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
  */
 #define EXT_INIT_MAX_LEN	(1UL << 15)
 #define EXT_UNINIT_MAX_LEN	(EXT_INIT_MAX_LEN - 1)


 #define EXT_FIRST_EXTENT(__hdr__) \
 	((struct ext4_extent *) (((char *) (__hdr__)) +		\
 				 sizeof(struct ext4_extent_header)))
 #define EXT_FIRST_INDEX(__hdr__) \
 	((struct ext4_extent_idx *) (((char *) (__hdr__)) +	\
 				     sizeof(struct ext4_extent_header)))
 #define EXT_HAS_FREE_INDEX(__path__) \
 	(le16_to_cpu((__path__)->p_hdr->eh_entries) \
 				     < le16_to_cpu((__path__)->p_hdr->eh_max))
 #define EXT_LAST_EXTENT(__hdr__) \
 	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
 #define EXT_LAST_INDEX(__hdr__) \
 	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
 #define EXT_MAX_EXTENT(__hdr__) \
 	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
 #define EXT_MAX_INDEX(__hdr__) \
 	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)

 static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
 {
 	return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
 }

 static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
 {
 	return (struct ext4_extent_header *) bh->b_data;
 }

 static inline unsigned short ext_depth(struct inode *inode)
 {
 	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
 }

 static inline void ext4_ext_tree_changed(struct inode *inode)
 {
 	EXT4_I(inode)->i_ext_generation++;
 }

 static inline void
 ext4_ext_invalidate_cache(struct inode *inode)
 {
 	EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
 }

 static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
 {
 	/* We can not have an uninitialized extent of zero length! */
 	BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
 	ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
 }

 static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
 {
 	/* Extent with ee_len of 0x8000 is treated as an initialized extent */
 	return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
 }

 static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
 {
 	return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
 		le16_to_cpu(ext->ee_len) :
 		(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
 }

 extern int ext4_extent_tree_init(handle_t *, struct inode *);
 extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
 extern int ext4_ext_try_to_merge(struct inode *inode,
 				 struct ext4_ext_path *path,
 				 struct ext4_extent *);
 extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
 extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
 extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *);
 extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *);

 #endif /* _LINUX_EXT4_EXTENTS */
	/*
	* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
	* Written by Alex Tomas <alex@clusterfs.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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public Licens
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
	*/

	#ifndef _LINUX_EXT4_EXTENTS
	#define _LINUX_EXT4_EXTENTS

	#include <linux/ext4_fs.h>

	/*
	* With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
	* becomes very small, so index split, in-depth growing and
	* other hard changes happen much more often.
	* This is for debug purposes only.
	*/
	#define AGGRESSIVE_TEST_

	/*
	* With EXTENTS_STATS defined, the number of blocks and extents
	* are collected in the truncate path. They'll be shown at
	* umount time.
	*/
	#define EXTENTS_STATS__

	/*
	* If CHECK_BINSEARCH is defined, then the results of the binary search
	* will also be checked by linear search.
	*/
	#define CHECK_BINSEARCH__

	/*
	* If EXT_DEBUG is defined you can use the 'extdebug' mount option
	* to get lots of info about what's going on.
	*/
	#define EXT_DEBUG__
	#ifdef EXT_DEBUG
	#define ext_debug(a...) printk(a)
	#else
	#define ext_debug(a...)
	#endif

	/*
	* If EXT_STATS is defined then stats numbers are collected.
	* These number will be displayed at umount time.
	*/
	#define EXT_STATS_


	/*
	* ext4_inode has i_block array (60 bytes total).
	* The first 12 bytes store ext4_extent_header;
	* the remainder stores an array of ext4_extent.
	*/

	/*
	* This is the extent on-disk structure.
	* It's used at the bottom of the tree.
	*/
	struct ext4_extent {
	__le32 ee_block; /* first logical block extent covers */
	__le16 ee_len; /* number of blocks covered by extent */
	__le16 ee_start_hi; /* high 16 bits of physical block */
	__le32 ee_start_lo; /* low 32 bits of physical block */
	};

	/*
	* This is index on-disk structure.
	* It's used at all the levels except the bottom.
	*/
	struct ext4_extent_idx {
	__le32 ei_block; /* index covers logical blocks from 'block' */
	__le32 ei_leaf_lo; /* pointer to the physical block of the next *
	* level. leaf or next index could be there */
	__le16 ei_leaf_hi; /* high 16 bits of physical block */
	__u16 ei_unused;
	};

	/*
	* Each block (leaves and indexes), even inode-stored has header.
	*/
	struct ext4_extent_header {
	__le16 eh_magic; /* probably will support different formats */
	__le16 eh_entries; /* number of valid entries */
	__le16 eh_max; /* capacity of store in entries */
	__le16 eh_depth; /* has tree real underlying blocks? */
	__le32 eh_generation; /* generation of the tree */
	};

	#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)

	/*
	* Array of ext4_ext_path contains path to some extent.
	* Creation/lookup routines use it for traversal/splitting/etc.
	* Truncate uses it to simulate recursive walking.
	*/
	struct ext4_ext_path {
	ext4_fsblk_t p_block;
	__u16 p_depth;
	struct ext4_extent *p_ext;
	struct ext4_extent_idx *p_idx;
	struct ext4_extent_header *p_hdr;
	struct buffer_head *p_bh;
	};

	/*
	* structure for external API
	*/

	#define EXT4_EXT_CACHE_NO 0
	#define EXT4_EXT_CACHE_GAP 1
	#define EXT4_EXT_CACHE_EXTENT 2

	/*
	* to be called by ext4_ext_walk_space()
	* negative retcode - error
	* positive retcode - signal for ext4_ext_walk_space(), see below
	* callback must return valid extent (passed or newly created)
	*/
	typedef int (ext_prepare_callback)(struct inode , struct ext4_ext_path *,
	struct ext4_ext_cache *,
	void *);

	#define EXT_CONTINUE 0
	#define EXT_BREAK 1
	#define EXT_REPEAT 2


	#define EXT_MAX_BLOCK 0xffffffff

	/*
	* EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
	* initialized extent. This is 2^15 and not (2^16 - 1), since we use the
	* MSB of ee_len field in the extent datastructure to signify if this
	* particular extent is an initialized extent or an uninitialized (i.e.
	* preallocated).
	* EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
	* uninitialized extent.
	* If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
	* uninitialized one. In other words, if MSB of ee_len is set, it is an
	* uninitialized extent with only one special scenario when ee_len = 0x8000.
	* In this case we can not have an uninitialized extent of zero length and
	* thus we make it as a special case of initialized extent with 0x8000 length.
	* This way we get better extent-to-group alignment for initialized extents.
	* Hence, the maximum number of blocks we can have in an initialized
	* extent is 2^15 (32768) and in an uninitialized extent is 2^15-1 (32767).
	*/
	#define EXT_INIT_MAX_LEN (1UL << 15)
	#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)


	#define EXT_FIRST_EXTENT(__hdr__) \
	((struct ext4_extent ) (((char ) (__hdr__)) + \
	sizeof(struct ext4_extent_header)))
	#define EXT_FIRST_INDEX(__hdr__) \
	((struct ext4_extent_idx ) (((char ) (__hdr__)) + \
	sizeof(struct ext4_extent_header)))
	#define EXT_HAS_FREE_INDEX(__path__) \
	(le16_to_cpu((__path__)->p_hdr->eh_entries) \
	< le16_to_cpu((__path__)->p_hdr->eh_max))
	#define EXT_LAST_EXTENT(__hdr__) \
	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
	#define EXT_LAST_INDEX(__hdr__) \
	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
	#define EXT_MAX_EXTENT(__hdr__) \
	(EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
	#define EXT_MAX_INDEX(__hdr__) \
	(EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)

	static inline struct ext4_extent_header ext_inode_hdr(struct inode inode)
	{
	return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
	}

	static inline struct ext4_extent_header ext_block_hdr(struct buffer_head bh)
	{
	return (struct ext4_extent_header *) bh->b_data;
	}

	static inline unsigned short ext_depth(struct inode *inode)
	{
	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
	}

	static inline void ext4_ext_tree_changed(struct inode *inode)
	{
	EXT4_I(inode)->i_ext_generation++;
	}

	static inline void
	ext4_ext_invalidate_cache(struct inode *inode)
	{
	EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
	}

	static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
	{
	/* We can not have an uninitialized extent of zero length! */
	BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
	ext->ee_len \|= cpu_to_le16(EXT_INIT_MAX_LEN);
	}

	static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
	{
	/* Extent with ee_len of 0x8000 is treated as an initialized extent */
	return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
	}

	static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
	{
	return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
	le16_to_cpu(ext->ee_len) :
	(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
	}

	extern int ext4_extent_tree_init(handle_t , struct inode );
	extern int ext4_ext_calc_credits_for_insert(struct inode , struct ext4_ext_path );
	extern int ext4_ext_try_to_merge(struct inode *inode,
	struct ext4_ext_path *path,
	struct ext4_extent *);
	extern unsigned int ext4_ext_check_overlap(struct inode , struct ext4_extent , struct ext4_ext_path *);
	extern int ext4_ext_insert_extent(handle_t , struct inode , struct ext4_ext_path , struct ext4_extent );
	extern int ext4_ext_walk_space(struct inode , unsigned long, unsigned long, ext_prepare_callback, void );
	extern struct ext4_ext_path * ext4_ext_find_extent(struct inode , int, struct ext4_ext_path );

	#endif /* _LINUX_EXT4_EXTENTS */