On 29/10/2015 14:18, Mike Snitzer wrote: > > 4) dmesg shows that scsi_verify_blk_ioctl() failed for SG_IO (0x2285); > > it returns -ENOIOCTLCMD, later replaced with -ENOTTY in vfs_ioctl(). > > > > $ dmesg > > <...> > > [] device-mapper: multipath: Failing path 65:144. > > [] device-mapper: multipath: Failing path 67:144. > > [] device-mapper: multipath: Failing path 65:224. > > [] device-mapper: multipath: Failing path 68:32. > > [] sgio_inquiry: sending ioctl 2285 to a partition! > > So scsi_verify_blk_ioctl() considers the ioctl invalid. But that's wrong, I think. It's a false positive in scsi_verify_blk_ioctl(). If the ioctl is valid when bdev becomes non-NULL (and it will be if ti->len becomes equal to i_size_read(bdev->bd_inode) >> SECTOR_SHIFT), you should not return -ENOIOCTLCMD aka ENOTTY, because userspace doesn't think the ioctls can go away and come back. So Hannes's patch broke the userspace ABI. :( Paolo -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
