On Fri, Oct 13, 2017 at 02:45:51PM +0200, Matias Bjørling wrote: > From: Rakesh Pandit <rak...@tuxera.com> > > When a virtual block device is formatted and mounted after creating > with "nvme lnvm create... -t pblk", a removal from "nvm lnvm remove" > would result in this: > > 446416.309757] bdi-block not registered > [446416.309773] ------------[ cut here ]------------ > [446416.309780] WARNING: CPU: 3 PID: 4319 at fs/fs-writeback.c:2159 > __mark_inode_dirty+0x268/0x340 > > Ideally removal should return -EBUSY as block device is mounted after > formatting. This patch tries to address this checking if whole device > or any partition of it already mounted or not before removal.
How is this different from any other block device that can be removed even if a file system is mounted? > > Whole device is checked using "bd_super" member of block device. This > member is always set once block device has been mounted using a > filesystem. Another member "bd_part_count" takes care of checking any > if any partitions are under use. "bd_part_count" is only updated > under locks when partitions are opened or closed (first open and last > release). This at least does take care sending -EBUSY if removal is > being attempted while whole block device or any partition is mounted. > That's a massive layering violation, and a driver has no business looking at these fields.
