fuse: simplify local variables holding writeback cache state

There are two instances of "bool is_wb = fc->writeback_cache" where the
actual use mostly involves checking "is_wb && S_ISREG(inode->i_mode)".

Clean up these cases by storing the second condition in the local variable.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dir.c

@@ -1561,10 +1561,10 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 	struct fuse_setattr_in inarg;
 	struct fuse_attr_out outarg;
 	bool is_truncate = false;
-	bool is_wb = fc->writeback_cache;
+	bool is_wb = fc->writeback_cache && S_ISREG(inode->i_mode);
 	loff_t oldsize;
 	int err;
-	bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
+	bool trust_local_cmtime = is_wb;
 	bool fault_blocked = false;
 
 	if (!fc->default_permissions)
@@ -1608,7 +1608,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 	}
 
 	/* Flush dirty data/metadata before non-truncate SETATTR */
-	if (is_wb && S_ISREG(inode->i_mode) &&
+	if (is_wb &&
 	    attr->ia_valid &
 			(ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_MTIME_SET |
 			 ATTR_TIMES_SET)) {
@@ -1679,7 +1679,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 				      attr_timeout(&outarg));
 	oldsize = inode->i_size;
 	/* see the comment in fuse_change_attributes() */
-	if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
+	if (!is_wb || is_truncate)
 		i_size_write(inode, outarg.attr.size);
 
 	if (is_truncate) {

fs/fuse/inode.c

@@ -223,7 +223,7 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	bool is_wb = fc->writeback_cache;
+	bool is_wb = fc->writeback_cache && S_ISREG(inode->i_mode);
 	loff_t oldsize;
 	struct timespec64 old_mtime;
 
@@ -243,7 +243,7 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 	 * extend local i_size without keeping userspace server in sync. So,
 	 * attr->size coming from server can be stale. We cannot trust it.
 	 */
-	if (!is_wb || !S_ISREG(inode->i_mode))
+	if (!is_wb)
 		i_size_write(inode, attr->size);
 	spin_unlock(&fi->lock);