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 (yizhang...@gmail.com) for root causing the problem.

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

Reported-by: Miklos Szeredi <mik...@szeredi.hu>
Signed-off-by: Tahsin Erdogan <tah...@google.com>
---
 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

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