[PATCH 1/2] EXT4: Punch Hole Optimizations: Skip un-needed extent lookup
From: Allison Henderson <hidden>
Date: 2011-06-27 22:47:32
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
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 <redacted> --- v2->v3 Rebased to apply onto latest ext4 code :100644 100644 f815cc8... dc5a077... M fs/ext4/extents.c fs/ext4/extents.c | 23 +++++++++++++++++++++-- 1 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index f815cc8..dc5a077 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c@@ -3497,8 +3497,27 @@ 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; }
--
1.7.1