[PATCH 13/28] ext4: ext4_xattr_value_same() should return false for external data

From: Tahsin Erdogan
Date: Wed May 31 2017 - 04:28:00 EST


ext4_xattr_value_same() is used as a quick optimization in case the new
xattr value is identical to the previous value. When xattr value is
stored in a xattr inode the check becomes expensive so it is better to
just assume that they are not equal.

Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
---
fs/ext4/xattr.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 4dd8be16d175..681a9b5eefd8 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1428,6 +1428,9 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
{
void *value;

+ /* When e_value_inum is set the value is stored externally. */
+ if (s->here->e_value_inum)
+ return 0;
if (le32_to_cpu(s->here->e_value_size) != i->value_len)
return 0;
value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
--
2.13.0.219.gdb65acc882-goog