On 07/08/2016 07:23 AM, Christoph Hellwig wrote:
> So far we tried to rely on the SCSI 'all target ports' bit to register
> all path, but for many setups this didn't work properly as the different
> path aren seen as separate initiators to the target instead of multiple
> ports of the same initiator. Because of that we'll stop setting the
> 'all target ports' bit in SCSI, and let device mapper handle iterating
> over the device for each path and register it manually.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/md/dm.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 70 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 1b2f962..e4e98b7 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -3601,26 +3601,81 @@ void dm_free_md_mempools(struct dm_md_mempools *pools)
> kfree(pools);
> }
>
> -static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
> - u32 flags)
> +struct dm_pr {
> + u64 old_key;
> + u64 new_key;
> + u32 flags;
> + bool fail_early;
> +};
> +
> +static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
> + void *data)
> {
> struct mapped_device *md = bdev->bd_disk->private_data;
> - const struct pr_ops *ops;
> - fmode_t mode;
> - int r;
> + struct dm_table *table;
> + struct dm_target *ti;
> + int ret = 0, srcu_idx;
>
> - r = dm_grab_bdev_for_ioctl(md, &bdev, &mode);
> - if (r < 0)
> - return r;
> + table = dm_get_live_table(md, &srcu_idx);
> + if (!table || !dm_table_get_size(table))
> + return -ENOTTY;
>
> - ops = bdev->bd_disk->fops->pr_ops;
> - if (ops && ops->pr_register)
> - r = ops->pr_register(bdev, old_key, new_key, flags);
> - else
> - r = -EOPNOTSUPP;
> + /* We only support devices that have a single target */
> + ret = -ENOTTY;
> + if (dm_table_get_num_targets(table) != 1)
> + goto out;
> + ti = dm_table_get_target(table, 0);
>
> - bdput(bdev);
> - return r;
> + ret = -EINVAL;
> + if (!ti->type->iterate_devices)
> + goto out;
> +
> + ret = ti->type->iterate_devices(ti, fn, data);
> + if (ret)
> + goto out;
> +
> + ret = 0;
> +out:
> + dm_put_live_table(md, srcu_idx);
> + return ret;
> +}
> +
> +/*
> + * For register / unregister we need to manually call out to every path.
> + */
> +static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
> + sector_t start, sector_t len, void *data)
> +{
> + struct dm_pr *pr = data;
> + const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
> +
> + if (!ops || !ops->pr_register)
> + return -EOPNOTSUPP;
> + return ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
> +}
> +
> +static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
> + u32 flags)
> +{
> + struct dm_pr pr = {
> + .old_key = old_key,
> + .new_key = new_key,
> + .flags = flags,
> + .fail_early = true,
> + };
> + int ret;
> +
> + ret = dm_call_pr(bdev, __dm_pr_register, &pr);
> + if (ret && new_key) {
> + /* unregister all paths if we failed to register any path */
> + pr.old_key = new_key;
> + pr.new_key = 0;
> + pr.flags = 0;
> + pr.fail_early = false;
> + dm_call_pr(bdev, __dm_pr_register, &pr);
> + }
> +
> + return ret;
> }
>
> static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
>
Reviewed-by: Mike Christie <mchristi@xxxxxxxxxx>
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