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linux-next/fs/ext4/extents_status.h
Zheng Liu d100eef244 ext4: lookup block mapping in extent status tree
After tracking all extent status, we already have a extent cache in
memory.  Every time we want to lookup a block mapping, we can first
try to lookup it in extent status tree to avoid a potential disk I/O.

A new function called ext4_es_lookup_extent is defined to finish this
work.  When we try to lookup a block mapping, we always call
ext4_map_blocks and/or ext4_da_map_blocks.  So in these functions we
first try to lookup a block mapping in extent status tree.

A new flag EXT4_GET_BLOCKS_NO_PUT_HOLE is used in ext4_da_map_blocks
in order not to put a hole into extent status tree because this hole
will be converted to delayed extent in the tree immediately.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan kara <jack@suse.cz>
2013-02-18 00:29:59 -05:00

110 lines
2.9 KiB
C

/*
* fs/ext4/extents_status.h
*
* Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
* Modified by
* Allison Henderson <achender@linux.vnet.ibm.com>
* Zheng Liu <wenqing.lz@taobao.com>
*
*/
#ifndef _EXT4_EXTENTS_STATUS_H
#define _EXT4_EXTENTS_STATUS_H
/*
* Turn on ES_DEBUG__ to get lots of info about extent status operations.
*/
#ifdef ES_DEBUG__
#define es_debug(fmt, ...) printk(fmt, ##__VA_ARGS__)
#else
#define es_debug(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#endif
#define EXTENT_STATUS_WRITTEN 0x80000000 /* written extent */
#define EXTENT_STATUS_UNWRITTEN 0x40000000 /* unwritten extent */
#define EXTENT_STATUS_DELAYED 0x20000000 /* delayed extent */
#define EXTENT_STATUS_HOLE 0x10000000 /* hole */
#define EXTENT_STATUS_FLAGS (EXTENT_STATUS_WRITTEN | \
EXTENT_STATUS_UNWRITTEN | \
EXTENT_STATUS_DELAYED | \
EXTENT_STATUS_HOLE)
struct extent_status {
struct rb_node rb_node;
ext4_lblk_t es_lblk; /* first logical block extent covers */
ext4_lblk_t es_len; /* length of extent in block */
ext4_fsblk_t es_pblk; /* first physical block */
};
struct ext4_es_tree {
struct rb_root root;
struct extent_status *cache_es; /* recently accessed extent */
};
extern int __init ext4_init_es(void);
extern void ext4_exit_es(void);
extern void ext4_es_init_tree(struct ext4_es_tree *tree);
extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len, ext4_fsblk_t pblk,
unsigned long long status);
extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len);
extern void ext4_es_find_delayed_extent(struct inode *inode, ext4_lblk_t lblk,
struct extent_status *es);
extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
struct extent_status *es);
static inline int ext4_es_is_written(struct extent_status *es)
{
return (es->es_pblk & EXTENT_STATUS_WRITTEN);
}
static inline int ext4_es_is_unwritten(struct extent_status *es)
{
return (es->es_pblk & EXTENT_STATUS_UNWRITTEN);
}
static inline int ext4_es_is_delayed(struct extent_status *es)
{
return (es->es_pblk & EXTENT_STATUS_DELAYED);
}
static inline int ext4_es_is_hole(struct extent_status *es)
{
return (es->es_pblk & EXTENT_STATUS_HOLE);
}
static inline ext4_fsblk_t ext4_es_status(struct extent_status *es)
{
return (es->es_pblk & EXTENT_STATUS_FLAGS);
}
static inline ext4_fsblk_t ext4_es_pblock(struct extent_status *es)
{
return (es->es_pblk & ~EXTENT_STATUS_FLAGS);
}
static inline void ext4_es_store_pblock(struct extent_status *es,
ext4_fsblk_t pb)
{
ext4_fsblk_t block;
block = (pb & ~EXTENT_STATUS_FLAGS) |
(es->es_pblk & EXTENT_STATUS_FLAGS);
es->es_pblk = block;
}
static inline void ext4_es_store_status(struct extent_status *es,
unsigned long long status)
{
ext4_fsblk_t block;
block = (status & EXTENT_STATUS_FLAGS) |
(es->es_pblk & ~EXTENT_STATUS_FLAGS);
es->es_pblk = block;
}
#endif /* _EXT4_EXTENTS_STATUS_H */