don't bother with ->d_inode->i_sb - it's always equal to ->d_sb

... and neither can ever be NULL

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 24d03c7..a82e20e 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4851,7 +4851,7 @@
 			goto out;
 
 	if (!S_ISDIR(inode->i_mode)) {
-		if (!parent || d_really_is_negative(parent) || sb != d_inode(parent)->i_sb)
+		if (!parent || d_really_is_negative(parent) || sb != parent->d_sb)
 			goto out;
 		inode = d_inode(parent);
 	}
@@ -4872,7 +4872,7 @@
 			break;
 		}
 
-		if (!parent || d_really_is_negative(parent) || sb != d_inode(parent)->i_sb)
+		if (!parent || d_really_is_negative(parent) || sb != parent->d_sb)
 			break;
 
 		if (IS_ROOT(parent))
@@ -5285,7 +5285,7 @@
 	}
 
 	while (1) {
-		if (!parent || d_really_is_negative(parent) || sb != d_inode(parent)->i_sb)
+		if (!parent || d_really_is_negative(parent) || sb != parent->d_sb)
 			break;
 
 		inode = d_inode(parent);