block: re-add discard_granularity and alignment checks
In commit b49a087("block: remove split code in
blkdev_issue_{discard,write_same}"), discard_granularity and alignment
checks were removed. Ideally, with bio late splitting, the upper layers
shouldn't need to depend on device's limits.
Christoph reported a discard regression on the HGST Ultrastar SN100 NVMe
device when mkfs.xfs. We have not found the root cause yet.
This patch re-adds discard_granularity and alignment checks by reverting
the related changes in commit b49a087
. The good thing is now we can
remove the 2G discard size cap and just use UINT_MAX to avoid bi_size
overflow.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
parent
23d88271b4
commit
a22c4d7e34
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@ -26,13 +26,6 @@ static void bio_batch_end_io(struct bio *bio)
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bio_put(bio);
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}
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/*
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* Ensure that max discard sectors doesn't overflow bi_size and hopefully
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* it is of the proper granularity as long as the granularity is a power
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* of two.
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*/
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#define MAX_BIO_SECTORS ((1U << 31) >> 9)
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/**
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* blkdev_issue_discard - queue a discard
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* @bdev: blockdev to issue discard for
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@ -50,6 +43,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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DECLARE_COMPLETION_ONSTACK(wait);
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struct request_queue *q = bdev_get_queue(bdev);
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int type = REQ_WRITE | REQ_DISCARD;
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unsigned int granularity;
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int alignment;
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struct bio_batch bb;
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struct bio *bio;
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int ret = 0;
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@ -61,6 +56,10 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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if (!blk_queue_discard(q))
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return -EOPNOTSUPP;
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/* Zero-sector (unknown) and one-sector granularities are the same. */
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granularity = max(q->limits.discard_granularity >> 9, 1U);
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alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
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if (flags & BLKDEV_DISCARD_SECURE) {
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if (!blk_queue_secdiscard(q))
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return -EOPNOTSUPP;
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@ -74,7 +73,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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blk_start_plug(&plug);
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while (nr_sects) {
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unsigned int req_sects;
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sector_t end_sect;
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sector_t end_sect, tmp;
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bio = bio_alloc(gfp_mask, 1);
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if (!bio) {
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@ -82,8 +81,22 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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break;
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}
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req_sects = min_t(sector_t, nr_sects, MAX_BIO_SECTORS);
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/* Make sure bi_size doesn't overflow */
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req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
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/*
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* If splitting a request, and the next starting sector would be
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* misaligned, stop the discard at the previous aligned sector.
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*/
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end_sect = sector + req_sects;
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tmp = end_sect;
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if (req_sects < nr_sects &&
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sector_div(tmp, granularity) != alignment) {
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end_sect = end_sect - alignment;
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sector_div(end_sect, granularity);
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end_sect = end_sect * granularity + alignment;
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req_sects = end_sect - sector;
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}
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bio->bi_iter.bi_sector = sector;
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bio->bi_end_io = bio_batch_end_io;
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