[PATCH] ext4: add missing xattr hash update

From: Tahsin Erdogan
Date: Sun Aug 06 2017 - 16:03:43 EST


When updating an extended attribute, if the padded value sizes are the
same, a shortcut is taken to avoid the bulk of the work. This was fine
until the xattr hash update was moved inside ext4_xattr_set_entry().
With that change, the hash update got missed in the shortcut case.

Thanks to ZhangYi (yizhang089@xxxxxxxxx) for root causing the problem.

Fixes: daf8328172df ("ext4: eliminate xattr entry e_hash recalculation for removes")

Reported-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
---
fs/ext4/xattr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 82a5af9f6668..3dd970168448 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1543,7 +1543,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
/* Clear padding bytes. */
memset(val + i->value_len, 0, new_size - i->value_len);
}
- return 0;
+ goto update_hash;
}

/* Compute min_offs and last. */
@@ -1707,6 +1707,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
here->e_value_size = cpu_to_le32(i->value_len);
}

+update_hash:
if (i->value) {
__le32 hash = 0;

@@ -1725,7 +1726,8 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
here->e_name_len,
&crc32c_hash, 1);
} else if (is_block) {
- __le32 *value = s->base + min_offs - new_size;
+ __le32 *value = s->base + le16_to_cpu(
+ here->e_value_offs);

hash = ext4_xattr_hash_entry(here->e_name,
here->e_name_len, value,
--
2.14.0.rc1.383.gd1ce394fe2-goog