block: don't try to discard from __blkdev_issue_zeroout (bef13315) · Commits · 戴 / test

Discard can return -EIO asynchronously if the alignment for the request isn't suitable for the driver, which makes a proper fallback to other methods in __blkdev_issue_zeroout impossible. Thus only issue a sync discard from blkdev_issue_zeroout an don't try discard at all from __blkdev_issue_zeroout as a non-invasive workaround. One more reason why abusing discard for zeroing must die.. Signed-off-by:

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

Eryu Guan <eguan@redhat.com> Fixes: ("block: add async variant of blkdev_issue_zeroout") Signed-off-by:

Jens Axboe <axboe@fb.com>

block/blk-lib.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -301,13 +301,6 @@ int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		if ((sector \| nr_sects) & bs_mask)
		return -EINVAL;

		if (discard) {
		ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
		BLKDEV_DISCARD_ZERO, biop);
		if (ret == 0 \|\| (ret && ret != -EOPNOTSUPP))
		goto out;
		}

		ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
		biop);
		if (ret == 0 \|\| (ret && ret != -EOPNOTSUPP))
		@@ -370,6 +363,12 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
		struct bio *bio = NULL;
		struct blk_plug plug;

		if (discard) {
		if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
		BLKDEV_DISCARD_ZERO))
		return 0;
		}

		blk_start_plug(&plug);
		ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask,
		&bio, discard);

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