linux-ext4 - [PATCH 1/2] EXT4: Punch Hole Optimizations: Skip un-needed extent lookup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 27 Jun 2011 15:49:50 -0700
From:	Allison Henderson <achender@...ux.vnet.ibm.com>
To:	linux-ext4@...r.kernel.org
Cc:	Allison Henderson <achender@...ux.vnet.ibm.com>
Subject: [PATCH 1/2] 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@...ux.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(-)

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

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html