Hey Milan, sorry for the late answer -- I thought nobody replied to the topic because I had the grouping setting messed up in my mail client. Only now that I looked in the messages again because of something totally unrelated I saw your response. On 25.05.2015 14:38, Milan Broz wrote: >> Afterwards I fork/exec the command "dmsetup remove foobar". This yields: >> >> device-mapper: remove ioctl on foobar failed: Device or resource busy >> Command failed > > Usually this is caused by running blkid (automatically running from udev rules) > which react to close-on-write on the device and keep the device open while scanning. > (You can try to run lsof, there is a chance you will see the process blocking > this device.) Ah, yes, indeed I do see a blkid process there. > Recent device mapper tries to retry removal operation, so if you use > recent dmsetup (or cryptsetup close command) you should see that it > tries several times. Yes, I saw that option, but in some cases it wouldn't wait long enough in my case and still return EBUSY. > First option is to disable WATCH rule in udev rules and check if this helps. > (Unfortunately this has some side effects.) > > Better solution is probably explicitly call "udevadm settle" instead > of sleep(). Still not perfect (it waits for all devices/udev processes), > but I am afraid there is nothing better yet to synchronize with these scans. Hm, I don't think I want a change in the udev config, so I'm going to navigate around this issue somhow. In any case my main worry was that I was doing something wrong which would cause this behavior. That udev calls blkid which causes the EBUSY actually is a good thing (because I can reasonably assume that blkid will terminate after a rather short amount of time). So I thank you for your response, clearing this up. Best regards, Johannes -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
