On Tue, May 16, 2017 at 05:39:14PM +0800, Anand Jain wrote:
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
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---
