On Thu, 1 Dec 2016, wangyijing wrote: > > >>> It probably is a duplicate set_capacity, but has anyone tested bringing > >>> on > >>> a writeback volume, and late-attaching the cache volume with this patch > >>> applied? > >>> > >>> Otherwise stated, is it possible to get the backing device attached > >>> without setting the capacity? > >> > >> Hi Eric, I tested this case in following steps, the result is fine, the > >> capability is setted. > >> > >> [root@38 sys]# make-bcache -B /dev/nvme1n1 > >> UUID: 6758bd42-c226-4de9-a6d5-fb003af63f9f > >> Set UUID: 2661eadd-79b4-4c56-a2fb-9f8b505aa9fd > >> version: 1 > >> block_size: 1 > >> data_offset: 16 > >> [root@38 sys]# ls /dev/bcache > >> bcache/ bcache0 > >> [root@38 sys]# fdisk -l > >> Disk /dev/nvme1n1: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors > >> Units: sectors of 1 * 512 = 512 bytes > >> Sector size (logical/physical): 512 bytes / 512 bytes > >> I/O size (minimum/optimal): 512 bytes / 512 bytes > >> .... > >> Disk /dev/bcache0: 1.8 TiB, 2000398925824 bytes, 3907029152 sectors > >> Units: sectors of 1 * 512 = 512 bytes > >> Sector size (logical/physical): 512 bytes / 512 bytes > >> I/O size (minimum/optimal): 512 bytes / 512 bytes > >> .... > >> [root@38 sys]# make-bcache -C /dev/ram0 > >> UUID: b64a4425-b9c1-4650-9cab-3856410c9566 > >> Set UUID: a0a31965-a89d-43b6-a5d6-968897abeb7a > >> version: 0 > >> nbuckets: 1024 > >> block_size: 1 > >> bucket_size: 1024 > >> nr_in_set: 1 > >> nr_this_dev: 0 > >> first_bucket: 1 > >> [root@38 sys]# echo a0a31965-a89d-43b6-a5d6-968897abeb7a > > >> /sys/block/bcache0/bcache/attach > >> [root@38 sys]# echo writeback > /sys/block/bcache0/bcache/cache_mode > >> [root@38 sys]# mount /dev/bcache0 /tmp > >> [root@38 sys]# cd /tmp/ > >> [root@38 tmp]# fio ~/fio_write.sh > >> file1: (g=0): rw=randwrite, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1 > >> fio-2.2.8 > >> Starting 1 thread > >> file1: Laying out IO file(s) (1 file(s) / 128MB) > >> Jobs: 1 (f=1): [w(1)] [0.0% done] [0KB/177.2MB/0KB /s] [0/45.4K/0 iops] > >> [eta 05h:33m:13s] > >> > >> Thanks! > >> Yijing. > > > > I want to make sure that the set_capacity call that happens on cache > > attachment is not necessary when a backing device is attached without > > Hi Eric, set_capacity() which removed in this patch is happened at > cached_dev_init() > which is called when register a backing device, what do you mean > "set_capacity call that happens on cache > > attachment" ?
I'm sorry, you are correct. I though this was the cache-dev attachment, not the cached-dev attachment. Looks good. Reviewed-by: Eric Wheeler <bca...@linux.ewheeler.net> -- Eric Wheeler > > > > its dirty writeback cache since bcache0 is not presented until the cache > > attaches in that case. > > I found bcache0 device present once we do make-bcache -B /dev/nvme1n1. before > attach the cache set. > So I missed something ? > > > > > Can you also unregister the volume, attach the backing device first, and > > then the cache while the cache is dirty to make sure that the size is set > > correctly? > > When I unregister the cache device, I found all the dirty data has been > flushed to > backing device, so how can I do the test the case as you point ? > > Thanks! > Yijing. > > > > > -- > > Eric Wheeler > > > >> > >>> > >>> -Eric > >>> > >>>> dc->disk.disk->queue->backing_dev_info.ra_pages = > >>>> max(dc->disk.disk->queue->backing_dev_info.ra_pages, > >>>> q->backing_dev_info.ra_pages); > >>>> -- > >>>> 2.5.0 > >>>> > >>>> -- > >>>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" > >>>> in > >>>> the body of a message to majord...@vger.kernel.org > >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > >>>> > >>> > >>> . > >>> > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in > >> the body of a message to majord...@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >
