(I originally reported this problem here: https://bugzilla.kernel.org/show_bug.cgi?id=200439) When I updated from 4.14 to 4.16, my LVM snapshotting script broke for no apparent reason. My script has the following line, and it fails like this: + lvcreate --size 5G --snapshot --name snap0 --permission r /dev/mapper/vg0-lvol_rootfs device-mapper: create ioctl on vg0-snap0-cowLVM-sDdIeh9cecWdaNyRfZC31mxgfwTa4sOeHMJXVOykGVRtfP6Aii7IHvwS066AOLOM-cow failed: Device or resource busy Failed to lock logical volume vg0/lvol_rootfs. Aborting. Manual intervention required. At the same time, some errors appear in dmesg as well: [ 26.145279] generic_make_request: Trying to write to read-only block-device dm-3 (partno 0) [ 26.145288] device-mapper: persistent snapshot: write_header failed [ 26.145847] device-mapper: table: 253:4: snapshot: Failed to read snapshot metadata [ 26.145851] device-mapper: ioctl: error adding target to table I bisected the vanilla kernel, and the first bad commit is [721c7fc701c71f693307d274d2b346a1ecd4a534] block: fail op_is_write() requests to read-only partitions
