ext2: add setlease file operation

Add the setlease file_operation to ext2_file_operations and
ext2_dir_operations, pointing to generic_setlease.  A future patch will
change the default behavior to reject lease attempts with -EINVAL when
there is no setlease file operation defined. Add generic_setlease to
retain the ability to set leases on this filesystem.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260108-setlease-6-20-v1-5-ea4dec9b67fa@kernel.org
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/ext2/dir.c

@@ -24,6 +24,7 @@
 
 #include "ext2.h"
 #include <linux/buffer_head.h>
+#include <linux/filelock.h>
 #include <linux/pagemap.h>
 #include <linux/swap.h>
 #include <linux/iversion.h>
@@ -734,4 +735,5 @@ const struct file_operations ext2_dir_operations = {
 	.compat_ioctl	= ext2_compat_ioctl,
 #endif
 	.fsync		= ext2_fsync,
+	.setlease	= generic_setlease,
 };

fs/ext2/file.c

@@ -22,6 +22,7 @@
 #include <linux/time.h>
 #include <linux/pagemap.h>
 #include <linux/dax.h>
+#include <linux/filelock.h>
 #include <linux/quotaops.h>
 #include <linux/iomap.h>
 #include <linux/uio.h>
@@ -325,6 +326,7 @@ const struct file_operations ext2_file_operations = {
 	.get_unmapped_area = thp_get_unmapped_area,
 	.splice_read	= filemap_splice_read,
 	.splice_write	= iter_file_splice_write,
+	.setlease	= generic_setlease,
 };
 
 const struct inode_operations ext2_file_inode_operations = {