btrfs: send: check for inline extents in range_is_hole_in_parent()

Before accessing the disk_bytenr field of a file extent item we need
to check if we are dealing with an inline extent.
This is because for inline extents their data starts at the offset of
the disk_bytenr field. So accessing the disk_bytenr
means we are accessing inline data or in case the inline data is less
than 8 bytes we can actually cause an invalid
memory access if this inline extent item is the first item in the leaf
or access metadata from other items.

Fixes: 82bfb2e ("Btrfs: incremental send, fix unnecessary hole writes for sparse files")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: adam900710

fs/btrfs/send.c

@@ -6382,6 +6382,8 @@ static int range_is_hole_in_parent(struct send_ctx *sctx,
 		extent_end = btrfs_file_extent_end(path);
 		if (extent_end <= start)
 			goto next;
+		if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE)
+			return 0;
 		if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
 			search_start = extent_end;
 			goto next;