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authorZheng Liu <wenqing.lz@taobao.com>2013-02-18 00:29:59 -0500
committerTheodore Ts'o <tytso@mit.edu>2013-02-18 00:29:59 -0500
commitd100eef2440fea13e4f09e88b1c8bcbca64beb9f (patch)
tree2451dc4582b43a30b414c89108b75148d48c9b57 /fs/ext4/extents_status.h
parentf7fec032aa782d3fd7e51fbdf08aa3a296c01500 (diff)
downloadlinux-d100eef2440fea13e4f09e88b1c8bcbca64beb9f.tar.bz2
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.h2
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)
{