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| author | Zheng Liu <wenqing.lz@taobao.com> | 2013-02-18 00:29:59 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-02-18 00:29:59 -0500 |
| commit | d100eef2440fea13e4f09e88b1c8bcbca64beb9f (patch) | |
| tree | 2451dc4582b43a30b414c89108b75148d48c9b57 /fs/ext4/extents_status.h | |
| parent | f7fec032aa782d3fd7e51fbdf08aa3a296c01500 (diff) | |
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>
Diffstat (limited to 'fs/ext4/extents_status.h')
| -rw-r--r-- | fs/ext4/extents_status.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h index 3f69d097c6e7..8ffc90c784fa 100644 --- a/fs/ext4/extents_status.h +++ b/fs/ext4/extents_status.h @@ -53,6 +53,8 @@ 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) { |