From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.9]:51342 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750891AbcFXHBC (ORCPT ); Fri, 24 Jun 2016 03:01:02 -0400 From: Christoph Hellwig To: axboe@fb.com Cc: shli@fb.com, martin.petersen@oracle.com, snitzer@redhat.com, sitsofe@yahoo.com, linux-block@vger.kernel.org Subject: [PATCH 1/2] block: introduce BLKDEV_DISCARD_ZERO to fix zeroout Date: Fri, 24 Jun 2016 09:00:50 +0200 Message-Id: <1466751651-9900-2-git-send-email-hch@lst.de> In-Reply-To: <1466751651-9900-1-git-send-email-hch@lst.de> References: <1466751651-9900-1-git-send-email-hch@lst.de> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org Currently blkdev_issue_zeroout cascades down from discards (if the driver guarantees that discards zero data), to WRITE SAME and then to a loop writing zeroes. Unfortunately we ignore run-time EOPNOTSUPP errors in the block layer blkdev_issue_discard helper to work around DM volumes that may have mixed discard support underneath. This patch intoroduces a new BLKDEV_DISCARD_ZERO flag to blkdev_issue_discard that indicates we are called for zeroing operation. This allows both to ignore the EOPNOTSUPP hack and actually consolidating the discard_zeroes_data check into the function. Signed-off-by: Christoph Hellwig --- block/blk-lib.c | 17 +++++++++++------ include/linux/blkdev.h | 4 +++- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index 78626c2..45b35b1 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -36,12 +36,17 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, return -ENXIO; if (flags & BLKDEV_DISCARD_SECURE) { + if (flags & BLKDEV_DISCARD_ZERO) + return -EOPNOTSUPP; if (!blk_queue_secure_erase(q)) return -EOPNOTSUPP; op = REQ_OP_SECURE_ERASE; } else { if (!blk_queue_discard(q)) return -EOPNOTSUPP; + if ((flags & BLKDEV_DISCARD_ZERO) && + !q->limits.discard_zeroes_data) + return -EOPNOTSUPP; op = REQ_OP_DISCARD; } @@ -116,7 +121,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, &bio); if (!ret && bio) { ret = submit_bio_wait(bio); - if (ret == -EOPNOTSUPP) + if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO)) ret = 0; } blk_finish_plug(&plug); @@ -241,11 +246,11 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, bool discard) { - struct request_queue *q = bdev_get_queue(bdev); - - if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data && - blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0) - return 0; + if (discard) { + if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, + BLKDEV_DISCARD_ZERO)) + return 0; + } if (bdev_write_same(bdev) && blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9d1e0a4..b65ca66 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1136,7 +1136,9 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, return bqt->tag_index[tag]; } -#define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */ + +#define BLKDEV_DISCARD_SECURE (1 << 0) /* issue a secure erase */ +#define BLKDEV_DISCARD_ZERO (1 << 1) /* must reliably zero data */ extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *); extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector, -- 2.1.4