Re: [PATCH 09/10] block: add FALLOC_FL_WRITE_ZEROES support

Christoph Hellwig
2025-06-11T06:11:04Z

On Wed, Jun 04, 2025 at 10:08:49AM +0800, Zhang Yi wrote:
> @@ -856,6 +856,13 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
> /* Fail if we don't recognize the flags. */
> if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
> return -EOPNOTSUPP;
> + /*
> + * Don't allow writing zeroes if the device does not enable the
> + * unmap write zeroes operation.
> + */
> + if (!bdev_write_zeroes_unmap(bdev) &&
> + (mode & FALLOC_FL_WRITE_ZEROES))

Cosmetic nitpick, but I'd turn the check around to check the mode first
as that's easier to read. The whole check also fits onto a single line:

if ((mode & FALLOC_FL_WRITE_ZEROES) && !bdev_write_zeroes_unmap(bdev))

Otherwise looks good:

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