[PATCH 3.2 039/106] ext4: keep existing extra fields when inode expands

From: Ben Hutchings
Date: Sat Sep 09 2017 - 18:43:22 EST


3.2.93-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>

commit 887a9730614727c4fff7cb756711b190593fc1df upstream.

ext4_expand_extra_isize() should clear only space between old and new
size.

Fixes: 6dd4ee7cab7e # v2.6.23
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/ext4/inode.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4637,8 +4637,9 @@ static int ext4_expand_extra_isize(struc
/* No extended attributes present */
if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
- memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
- new_extra_isize);
+ memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
+ EXT4_I(inode)->i_extra_isize, 0,
+ new_extra_isize - EXT4_I(inode)->i_extra_isize);
EXT4_I(inode)->i_extra_isize = new_extra_isize;
return 0;
}