/*
* 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 AGRESSIVE_TEST defined capacity of index/leaf blocks
* become very little, so index split, in-depth growing and
* other hard changes happens much more often
* this is for debug purposes only
*/
#define AGRESSIVE_TEST_
/*
* with EXTENTS_STATS defined number of blocks and extents
* are collected in truncate path. they'll be showed at
* umount time
*/
#define EXTENTS_STATS__
/*
* if CHECK_BINSEARCH defined, then results of binary search
* will be checked by linear search
*/
#define CHECK_BINSEARCH__
/*
* if EXT_DEBUG is defined you can use 'extdebug' mount option
* to get lots of info 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)
* first 12 bytes store ext4_extent_header
* the remain stores array of ext4_extent
*/
/*
* this is 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; /* low 32 bigs of physical block */
};
/*
* this is index on-disk structure
* it's used at all the levels, but the bottom
*/
struct ext4_extent_idx {
__le32 ei_block; /* index covers logical blocks from 'block' */
__le32 ei_leaf; /* pointer to the physical block of the next *
* level. leaf or next index could bet here */
__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 underlaying 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 {
__u32 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
#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;
}
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_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 */
