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ext4: lookup block mapping in extent status tree

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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>
This commit is contained in:
Zheng Liu
2013-02-18 00:29:59 -05:00
committed by Theodore Ts'o
parent f7fec032aa
commit d100eef244
6 changed files with 192 additions and 3 deletions
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56
include/trace/events/ext4.h
View File

@@ -2199,6 +2199,62 @@ TRACE_EVENT(ext4_es_find_delayed_extent_exit,
__entry->pblk, __entry->status)
);
TRACE_EVENT(ext4_es_lookup_extent_enter,
TP_PROTO(struct inode *inode, ext4_lblk_t lblk),
TP_ARGS(inode, lblk),
TP_STRUCT__entry(
__field( dev_t, dev )
__field( ino_t, ino )
__field( ext4_lblk_t, lblk )
),
TP_fast_assign(
__entry->dev = inode->i_sb->s_dev;
__entry->ino = inode->i_ino;
__entry->lblk = lblk;
),
TP_printk("dev %d,%d ino %lu lblk %u",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino, __entry->lblk)
);
TRACE_EVENT(ext4_es_lookup_extent_exit,
TP_PROTO(struct inode *inode, struct extent_status *es,
int found),
TP_ARGS(inode, es, found),
TP_STRUCT__entry(
__field( dev_t, dev )
__field( ino_t, ino )
__field( ext4_lblk_t, lblk )
__field( ext4_lblk_t, len )
__field( ext4_fsblk_t, pblk )
__field( unsigned long long, status )
__field( int, found )
),
TP_fast_assign(
__entry->dev = inode->i_sb->s_dev;
__entry->ino = inode->i_ino;
__entry->lblk = es->es_lblk;
__entry->len = es->es_len;
__entry->pblk = ext4_es_pblock(es);
__entry->status = ext4_es_status(es);
__entry->found = found;
),
TP_printk("dev %d,%d ino %lu found %d [%u/%u) %llu %llx",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long) __entry->ino, __entry->found,
__entry->lblk, __entry->len,
__entry->found ? __entry->pblk : 0,
__entry->found ? __entry->status : 0)
);
#endif /* _TRACE_EXT4_H */
/* This part must be outside protection */