Patchwork [1/2] EXT4: Punch Hole Optimizations: Skip un-needed extent lookup

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Submitter Allison Henderson
Date June 27, 2011, 10:49 p.m.
Message ID <1309214991-31141-2-git-send-email-achender@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/102289/
State Accepted
Headers show

Comments

Allison Henderson - June 27, 2011, 10:49 p.m.
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>
---
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(-)
Theodore Ts'o - July 18, 2011, 3:22 a.m.
On Mon, Jun 27, 2011 at 03:49:50PM -0700, Allison Henderson wrote:
> 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>

Thanks, added to the ext4 tree.

					- Ted
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Patch

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;
 		}