From e7786c3ae517b2c433edc91714e86be770e9f1ce Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Sat, 28 May 2011 20:58:38 +0000 Subject: [PATCH] btrfs: scrub: add explicit plugging With the removal of the implicit plugging scrub ends up doing more and smaller I/O than necessary. This patch adds explicit plugging per chunk. Signed-off-by: Arne Jansen Signed-off-by: Chris Mason --- fs/btrfs/scrub.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 2d1f8909a8e1..1204eab94028 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -348,9 +348,6 @@ static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, int ret; DECLARE_COMPLETION_ONSTACK(complete); - /* we are going to wait on this IO */ - rw |= REQ_SYNC; - bio = bio_alloc(GFP_NOFS, 1); bio->bi_bdev = bdev; bio->bi_sector = sector; @@ -359,6 +356,7 @@ static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, bio->bi_private = &complete; submit_bio(rw, bio); + /* this will also unplug the queue */ wait_for_completion(&complete); ret = !test_bit(BIO_UPTODATE, &bio->bi_flags); @@ -743,6 +741,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, struct btrfs_root *root = fs_info->extent_root; struct btrfs_root *csum_root = fs_info->csum_root; struct btrfs_extent_item *extent; + struct blk_plug plug; u64 flags; int ret; int slot; @@ -847,6 +846,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, * the scrub. This might currently (crc32) end up to be about 1MB */ start_stripe = 0; + blk_start_plug(&plug); again: logical = base + offset + start_stripe * increment; for (i = start_stripe; i < nstripes; ++i) { @@ -988,6 +988,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, scrub_submit(sdev); out: + blk_finish_plug(&plug); btrfs_free_path(path); return ret < 0 ? ret : 0; }