majianpeng <majianpeng@xxxxxxxxx> writes: >>The bigger question is whether we want to change this long-standing >>behaviour of how our write-back cache works. I don't know that it's >>really worth it, honestly. If you want to ensure data is on disk, you >>open the file O_SYNC or you issue an fsync, and those calls will return >>an error for a removed block device. So, I guess I'll ask the same >>question again: why are you looking at this? Is there some application >>you care about that does buffered I/O to the block device and never does >>an fsync? >> > Yes, for my company, we used our filesystem in userspace on block-device. > For the performance, we used buffer-wrtite not sync-write. > For my workload, we allow user to remove disk whether disk working or not. > Now, we check the state of disk from /proc/partitions at the same interval. > > This patchset don't change write-back cache works.It only let vfs know > the state of lower-device. I think it make a sense. I'm still curious to know how you maintain a consistent file system without the use of fsync, but that's an unrelated issue. I looked at the rescan partition code path more closely, and it will only really trigger if the partitions themselves aren't open. So, I don't think there is a problem in your approach. I'll ack patch 1. I still think patch 2 is not neessary. Please correct me if I'm wrong. Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
