From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:33818 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbdEPMAQ (ORCPT ); Tue, 16 May 2017 08:00:16 -0400 Date: Tue, 16 May 2017 05:00:15 -0700 From: Christoph Hellwig To: Anand Jain Cc: linux-btrfs@vger.kernel.org, linux-block@vger.kernel.org, dsterba@suse.cz Subject: Re: [PATCH 2/2] btrfs: Use blkdev_issue_flush_no_wait() Message-ID: <20170516120015.GB18649@infradead.org> References: <20170516093914.16035-1-anand.jain@oracle.com> <20170516093914.16035-3-anand.jain@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170516093914.16035-3-anand.jain@oracle.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Tue, May 16, 2017 at 05:39:14PM +0800, Anand Jain wrote: > Signed-off-by: Anand Jain An explanation on why things are changed is entirely missing here.. > --- > fs/btrfs/disk-io.c | 108 ++++++++++++++++------------------------------------- > fs/btrfs/volumes.h | 2 +- > 2 files changed, 33 insertions(+), 77 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 8685d67185d0..f059f9bdbbd7 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -3478,121 +3478,77 @@ static int write_dev_supers(struct btrfs_device *device, > } > > /* > - * endio for the write_dev_flush, this will wake anyone waiting > + * endio for blkdev_issues_flush_no_wait, this will wake anyone waiting > * for the barrier when it is done > */ > static void btrfs_end_empty_barrier(struct bio *bio) > { > - if (bio->bi_private) > - complete(bio->bi_private); > + struct btrfs_device *device; > + > + device = container_of(bio->bi_private, struct btrfs_device, > + flush_wait); > + > + device->last_flush_error = bio->bi_error; > + complete(&device->flush_wait); > + > bio_put(bio); > } > > -/* > - * trigger flushes for one the devices. If you pass wait == 0, the flushes are > - * sent down. With wait == 1, it waits for the previous flush. > - * > - * any device where the flush fails with eopnotsupp are flagged as not-barrier > - * capable > - */ > -static int write_dev_flush(struct btrfs_device *device, int wait) > +static void write_dev_flush(struct btrfs_device *device) > { > + int ret; > struct request_queue *q = bdev_get_queue(device->bdev); > - struct bio *bio; > - int ret = 0; > > if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) > - return 0; > - > - if (wait) { > - bio = device->flush_bio; > - if (!bio) > - return 0; > - > - wait_for_completion(&device->flush_wait); > - > - if (bio->bi_error) { > - ret = bio->bi_error; > - btrfs_dev_stat_inc_and_print(device, > - BTRFS_DEV_STAT_FLUSH_ERRS); > - } > - > - /* drop the reference from the wait == 0 run */ > - bio_put(bio); > - device->flush_bio = NULL; > - > - return ret; > - } > - > - /* > - * one reference for us, and we leave it for the > - * caller > - */ > - device->flush_bio = NULL; > - bio = btrfs_io_bio_alloc(GFP_NOFS, 0); > - if (!bio) > - return -ENOMEM; > - > - bio->bi_end_io = btrfs_end_empty_barrier; > - bio->bi_bdev = device->bdev; > - bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH; > - init_completion(&device->flush_wait); > - bio->bi_private = &device->flush_wait; > - device->flush_bio = bio; > - > - bio_get(bio); > - btrfsic_submit_bio(bio); > + return; > > - return 0; > + ret = blkdev_issue_flush_no_wait(device->bdev, GFP_NOFS, > + btrfs_end_empty_barrier, &device->flush_wait); > + if (ret) > + device->last_flush_error = ret; > + else > + device->last_flush_error = -1; > } > > /* > - * send an empty flush down to each device in parallel, > - * then wait for them > + * send flush down to each device in parallel, then wait for them. > */ > static int barrier_all_devices(struct btrfs_fs_info *info) > { > struct list_head *head; > struct btrfs_device *dev; > - int errors_send = 0; > int errors_wait = 0; > - int ret; > > /* send down all the barriers */ > head = &info->fs_devices->devices; > list_for_each_entry_rcu(dev, head, dev_list) { > + dev->last_flush_error = 0; > if (dev->missing) > continue; > + > + if (!dev->in_fs_metadata || !dev->writeable) > + continue; > + > if (!dev->bdev) { > - errors_send++; > + dev->last_flush_error = -ENXIO; > continue; > } > - if (!dev->in_fs_metadata || !dev->writeable) > - continue; > > - ret = write_dev_flush(dev, 0); > - if (ret) > - errors_send++; > + write_dev_flush(dev); > } > > /* wait for all the barriers */ > list_for_each_entry_rcu(dev, head, dev_list) { > - if (dev->missing) > - continue; > - if (!dev->bdev) { > - errors_wait++; > - continue; > - } > - if (!dev->in_fs_metadata || !dev->writeable) > - continue; > + if (dev->last_flush_error == -1) > + wait_for_completion(&dev->flush_wait); > > - ret = write_dev_flush(dev, 1); > - if (ret) > + if (dev->last_flush_error) > errors_wait++; > } > - if (errors_send > info->num_tolerated_disk_barrier_failures || > - errors_wait > info->num_tolerated_disk_barrier_failures) > + > + if (errors_wait > info->num_tolerated_disk_barrier_failures) > return -EIO; > + > return 0; > } > > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index c7d0fbc915ca..27af3a227bfb 100644 > --- a/fs/btrfs/volumes.h > +++ b/fs/btrfs/volumes.h > @@ -123,8 +123,8 @@ struct btrfs_device { > struct list_head resized_list; > > /* for sending down flush barriers */ > - struct bio *flush_bio; > struct completion flush_wait; > + int last_flush_error; > > /* per-device scrub information */ > struct scrub_ctx *scrub_device; > -- > 2.10.0 > ---end quoted text---