ext2: fix improper assignment for e_value_offs

In the process of changing value for existing EA,
there is an improper assignment of e_value_offs(setting to 0),
because it will be reset to incorrect value in the following
loop(shifting EA values before target). Delayed assignment
can avoid this issue.

Link: https://lore.kernel.org/r/20200603084429.25344-1-cgxu519@mykernel.net
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 943cc46..c802ea6 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -588,7 +588,6 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
 			/* Remove the old value. */
 			memmove(first_val + size, first_val, val - first_val);
 			memset(first_val, 0, size);
-			here->e_value_offs = 0;
 			min_offs += size;
 
 			/* Adjust all value offsets. */
@@ -600,6 +599,8 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
 						cpu_to_le16(o + size);
 				last = EXT2_XATTR_NEXT(last);
 			}
+
+			here->e_value_offs = 0;
 		}
 		if (value == NULL) {
 			/* Remove the old name. */