On 24.06.2017 15:56, Johannes Bauer wrote: > So I seem to have a very basic misunderstanding of what the cleaner > policy/dirty pages mean. Is there a way to force the cache to flush > entirely? Apparently, "dmsetup wait" and/or "sync" don't do the job. I'd like to expand on this, since I discovered something that worries me a bit just now: I do have a dm-cache setup for my main drive as well (3 TB HDD cached by 128 GB SSD). On top of dm-cache runs dm-crypt (LUKS). When playing around with my root fs, I tried to discard the whole cache. Therefore, I did -- with the LUKS container NOT open: dmsetup suspend cache-device dmsetup reload cache-device --table '0 5858433935 cache 253:1 253:0 8:19 512 0 cleaner 0' dmsetup resume cache-device dmsetup wait cache-device Again, "dmsetup wait" hung, with no obvious I/O being done (i.e., all disks were idle). I Ctrl-Ced out of it. The status showed no dirty pages. Since I was suspicious, I left the device with the "cleaner" policy and opened the LUKS container, then did an e2fsck -fn on the opened device. No errors found. Then I closed the LUKS container and performed "dmsetup remove" on the cache device (as well as the two other linear mappings). Then I re-opened LUKS on the origin device and ran e2fsck -fn there. File system errors! I am fully prepared to restore everything from backup. However, is this normal behavior or an issue? How am I supposed to discard an attached cache? How do I get the origin device back in sync with the cached device? Best regards, Johannes -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
