Commit dd5e2762 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: compression: add an ASSERT() to ensure the read-in length is sane 



There are already two bugs (one in zlib, one in zstd) that involved
compression path is not handling sector size < page size cases well.

So it makes more sense to make sure that btrfs_compress_folios() returns

Since we already have two bugs (one in zlib, one in zstd) in the
compression path resulting the @total_in be to larger than the
to-be-compressed range length, there is enough reason to add an ASSERT()
to make sure the total read-in length doesn't exceed the input length.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 90275a77

fs/btrfs/compression.c

+3 −0
Original line number Diff line number Diff line
@@ -1030,6 +1030,7 @@ int btrfs_compress_folios(unsigned int type_level, struct address_space *mapping 
{

	int type = btrfs_compress_type(type_level);

	int level = btrfs_compress_level(type_level);

	const unsigned long orig_len = *total_out;

	struct list_head *workspace;

	int ret;
@@ -1037,6 +1038,8 @@ int btrfs_compress_folios(unsigned int type_level, struct address_space *mapping 
	workspace = get_workspace(type, level);

	ret = compression_compress_pages(type, workspace, mapping, start, folios,

					 out_folios, total_in, total_out);

	/* The total read-in bytes should be no larger than the input. */

	ASSERT(*total_in <= orig_len);

	put_workspace(type, workspace);

	return ret;

}