Re: [PATCH 15/16] fscrypt: Merge bio.c and inline_crypt.c into block.c

[Christoph Hellwig <hch@lst.de>]

On Tue, Jun 23, 2026 at 10:03:33PM -0700, Eric Biggers wrote:
> Now that fscrypt always uses blk-crypto on block-based filesystems,
> there's no meaningful difference between bio.c and inline_crypt.c.
> Therefore merge the two files into one named block.c.
> 
> Note: I didn't carry over bio.c's "Copyright (C) 2015, Motorola
> Mobility", as none of the code that applied to remained.

Yeah the current from of the code is almost entirely mine,
with some slight traces of your earlier version.

> +struct fscrypt_zero_done {
> +	atomic_t		pending;
> +	blk_status_t		status;
> +	struct completion	done;
> +};
> +
> +static void fscrypt_zeroout_range_done(struct fscrypt_zero_done *done)
> +{
> +	if (atomic_dec_and_test(&done->pending))
> +		complete(&done->done);
> +}
> +
> +static void fscrypt_zeroout_range_end_io(struct bio *bio)
> +{
> +	struct fscrypt_zero_done *done = bio->bi_private;
> +
> +	if (bio->bi_status)
> +		cmpxchg(&done->status, 0, bio->bi_status);
> +	fscrypt_zeroout_range_done(done);
> +	bio_put(bio);
> +}
> +
> +/**
> + * fscrypt_zeroout_range() - zero out a range of blocks in an encrypted file
> + * @inode: the file's inode
> + * @pos: the first file position (in bytes) to zero out
> + * @sector: the first sector to zero out
> + * @len: bytes to zero out
> + *
> + * Zero out filesystem blocks in an encrypted regular file on-disk, i.e. write
> + * ciphertext blocks which decrypt to the all-zeroes block.  The blocks must be
> + * both logically and physically contiguous.  It's also assumed that the
> + * filesystem only uses a single block device, ->s_bdev.  @len must be a
> + * multiple of the file system logical block size.
> + *
> + * Note that since each block uses a different IV, this involves writing a
> + * different ciphertext to each block; we can't simply reuse the same one.
> + *
> + * Return: 0 on success; -errno on failure.
> + */
> +int fscrypt_zeroout_range(const struct inode *inode, loff_t pos,
> +			  sector_t sector, u64 len)

.. but I wonder if we should rename this and move it to libfs, as it
works just fine without encyption and file systems could call it
for the non-fscrypt case and consolidate on a single implementation.

But maybe some other time, no need to complicate this series.

Reviewed-by: Christoph Hellwig <hch@lst.de>