On Tue, 08 Oct 2019 14:05:28 +0200 Christian Schoenebeck <qemu_...@crudebyte.com> wrote:
> > I wonder though whether virtio-fs suffers from the same file ID collisions > problem when sharing multiple file systems. > I gave a try and it seems that virtio-fs might expose the inode numbers from different devices in the host, unvirtualized AND with the same device in the guest: # mkdir -p /var/tmp/virtio-fs/proc # mount --bind /proc /var/tmp/virtio-fs/proc # virtiofsd -o vhost_user_socket=/tmp/vhostqemu -o source=/var/tmp/virtio-fs -o cache=always and then started QEMU with: -chardev socket,id=char0,path=/tmp/vhostqemu \ -device vhost-user-fs-pci,queue-size=1024,chardev=char0,tag=myfs \ -m 4G -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \ -numa node,memdev=mem In the host: $ stat /var/tmp/virtio-fs File: /var/tmp/virtio-fs Size: 4096 Blocks: 8 IO Block: 4096 directory Device: fd00h/64768d Inode: 787796 Links: 4 Access: (0775/drwxrwxr-x) Uid: ( 1000/ greg) Gid: ( 1000/ greg) Context: unconfined_u:object_r:user_tmp_t:s0 Access: 2019-10-15 11:08:52.070080922 +0200 Modify: 2019-10-15 11:02:09.887404446 +0200 Change: 2019-10-15 11:02:09.887404446 +0200 Birth: 2019-10-13 19:13:04.009699354 +0200 [greg@bahia ~]$ stat /var/tmp/virtio-fs/FOO File: /var/tmp/virtio-fs/FOO Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: fd00h/64768d Inode: 790740 Links: 1 Access: (0664/-rw-rw-r--) Uid: ( 1000/ greg) Gid: ( 1000/ greg) Context: unconfined_u:object_r:user_tmp_t:s0 Access: 2019-10-15 11:02:09.888404448 +0200 Modify: 2019-10-15 11:02:09.888404448 +0200 Change: 2019-10-15 11:02:09.888404448 +0200 Birth: 2019-10-15 11:02:09.887404446 +0200 [greg@bahia ~]$ stat /var/tmp/virtio-fs/proc/fs File: /var/tmp/virtio-fs/proc/fs Size: 0 Blocks: 0 IO Block: 1024 directory Device: 4h/4d Inode: 4026531845 Links: 5 Access: (0555/dr-xr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Context: system_u:object_r:proc_t:s0 Access: 2019-10-01 14:50:09.223233901 +0200 Modify: 2019-10-01 14:50:09.223233901 +0200 Change: 2019-10-01 14:50:09.223233901 +0200 Birth: - In the guest: [greg@localhost ~]$ stat /mnt File: /mnt Size: 4096 Blocks: 8 IO Block: 4096 directory Device: 2dh/45d Inode: 787796 Links: 4 Access: (0775/drwxrwxr-x) Uid: ( 1000/ greg) Gid: ( 1000/ greg) Context: system_u:object_r:unlabeled_t:s0 Access: 2019-10-15 11:08:52.070080922 +0200 Modify: 2019-10-15 11:02:09.887404446 +0200 Change: 2019-10-15 11:02:09.887404446 +0200 Birth: - [greg@localhost ~]$ stat /mnt/FOO File: /mnt/FOO Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 2dh/45d Inode: 790740 Links: 1 Access: (0664/-rw-rw-r--) Uid: ( 1000/ greg) Gid: ( 1000/ greg) Context: system_u:object_r:unlabeled_t:s0 Access: 2019-10-15 11:02:09.888404448 +0200 Modify: 2019-10-15 11:02:09.888404448 +0200 Change: 2019-10-15 11:02:09.888404448 +0200 Birth: - [greg@localhost ~]$ stat /mnt/proc/fs File: /mnt/proc/fs Size: 0 Blocks: 0 IO Block: 1024 directory Device: 2dh/45d Inode: 4026531845 Links: 5 Access: (0555/dr-xr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Context: system_u:object_r:unlabeled_t:s0 Access: 2019-10-01 14:50:09.223233901 +0200 Modify: 2019-10-01 14:50:09.223233901 +0200 Change: 2019-10-01 14:50:09.223233901 +0200 Birth: - Unless I'm missing something, it seems that "virtio-fs" has the same issue we had on 9pfs before Christian's patches... :-\ -- Greg
