• Zheng Liu's avatar
    ext4: lookup block mapping in extent status tree · d100eef2
    Zheng Liu authored
    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: default avatarZheng Liu <wenqing.lz@taobao.com>
    Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    Cc: Jan kara <jack@suse.cz>
    d100eef2
ext4.h 55.2 KB