Switch from generic_block_fiemap to use the iomap version.  The only
interesting part is that ext2_get_blocks gets confused when being
asked for overly long ranges, so copy over the limit to the inode
size from generic_block_fiemap into ext2_fiemap.
Link: https://lore.kernel.org/r/20210720133341.405438-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
 # SPDX-License-Identifier: GPL-2.0-only
 config EXT2_FS
        tristate "Second extended fs support"
+       select FS_IOMAP
        help
          Ext2 is a standard Linux file system for hard disks.
 
 
 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                u64 start, u64 len)
 {
-       return generic_block_fiemap(inode, fieinfo, start, len,
-                                   ext2_get_block);
+       int ret;
+
+       inode_lock(inode);
+       len = min_t(u64, len, i_size_read(inode));
+       ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops);
+       inode_unlock(inode);
+
+       return ret;
 }
 
 static int ext2_writepage(struct page *page, struct writeback_control *wbc)