diff options
| 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/ext4.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/ext4.h')
| -rw-r--r-- | fs/ext4/ext4.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 5c31d6ac9500..329e7fba47d6 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -579,6 +579,8 @@ enum { #define EXT4_GET_BLOCKS_KEEP_SIZE 0x0080 /* Do not take i_data_sem locking in ext4_map_blocks */ #define EXT4_GET_BLOCKS_NO_LOCK 0x0100 + /* Do not put hole in extent cache */ +#define EXT4_GET_BLOCKS_NO_PUT_HOLE 0x0200 /* * Flags used by ext4_free_blocks |