ext4: punch hole optimizations: skip un-needed extent lookup

This patch optimizes the punch hole operation by skipping the
tree walking code that is used by truncate.  Since punch hole
is done through map blocks, the path to the extent is already
known in this function, so we do not need to look it up again.

Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Allison Henderson 2011-07-17 23:17:02 -04:00 committed by Theodore Ts'o
parent 3eb0865843
commit f7d0d3797f

View file

@ -3461,8 +3461,27 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
ext4_ext_mark_uninitialized(ex);
err = ext4_ext_remove_space(inode, map->m_lblk,
map->m_lblk + punched_out);
ext4_ext_invalidate_cache(inode);
err = ext4_ext_rm_leaf(handle, inode, path,
map->m_lblk, map->m_lblk + punched_out);
if (!err && path->p_hdr->eh_entries == 0) {
/*
* Punch hole freed all of this sub tree,
* so we need to correct eh_depth
*/
err = ext4_ext_get_access(handle, inode, path);
if (err == 0) {
ext_inode_hdr(inode)->eh_depth = 0;
ext_inode_hdr(inode)->eh_max =
cpu_to_le16(ext4_ext_space_root(
inode, 0));
err = ext4_ext_dirty(
handle, inode, path);
}
}
goto out2;
}