Hi, this patch-series is huge but brings a lot of basic "fun" net-namespace functionality to DLM. Currently you need a couple of Linux kernel instances running in e.g. Virtual Machines. With this patch-series I want to break out of this virtual machine world dealing with multiple kernels need to boot them all individually, etc. Now you can use DLM in only one Linux kernel instance and each "node" (previously represented by a virtual machine) is separate by a net-namespace. Why net-namespaces? It just fits to the DLM design for now, you need to have them anyway because the internal DLM socket handling on a per node basis. What we do additionally is to separate the DLM lockspaces (the lockspace that is being registered) by net-namespaces as this represents a "network entity" (node). There might be reasons to introduce a complete new kind of namespaces (locking namespace?) but I don't want to do this step now and as I said net-namespaces are required anyway for the DLM sockets. You need some new user space tooling as a new netlink net-namespace aware UAPI is introduced (but can co-exist with configfs that operates on init_net only). See [0] for more steps, there is a copr repo for the new tooling and can be enabled by: $ dnf copr enable aring/nldlm $ dnf install nldlm or compile it yourself. Then there is currently a very simple script [1] to show a 3 nodes cluster using gfs2 on a multiple loop block devices on a shared loop block device image (sounds weird but I do something like that). There are currently some user space synchronization issues that I solve by simple sleeps, but they are only user space problems. To test it I recommend some virtual machine "but only one" and run the [1] script. Afterwards you have in your executed net-namespace the 3 mountpoints /cluster/node1, /cluster/node2/ and /cluster/node3. Any vfs operations on those mountpoints acts as a per node entity operation. We can use it for testing, development and also scale testing to have a large number of nodes joining a lockspace (which seems to be a problem right now). Instead of running 1000 vms, we can run 1000 net-namespaces in a more resource limited environment. For me it seems gfs2 can handle several mounts and still separate the resource according their global variables. Their data structures e.g. glock hash seems to have in their key a separation for that (fsid?). However this is still an experimental feature we might run into issues that requires more separation related to net-namespaces. However basic testing seems to run just fine. Limitations I disable any functionality for the DLM character device that allow plock handling or do DLM locking from user space. Just don't use any plock locking in gfs2 for now. But basic vfs operations should work. You can even sniff DLM traffic on the created "dlmsw" virtual bridge. - Alex [0] https://gitlab.com/netcoder/nldlm [1] https://gitlab.com/netcoder/gfs2ns-examples/-/blob/main/three_nodes changes since v2: - move to ynl and introduce and use netlink yaml spec - put the nldlm.h DLM netlink header under UAPI directory - fix build issues building with CONFIG_NET disabled - fix possible nullpointer deference if lookup of lockspace failed Alexander Aring (12): dlm: introduce dlm_find_lockspace_name() dlm: disallow different configs nodeid storages dlm: add struct net to dlm_new_lockspace() dlm: handle port as __be16 network byte order dlm: use dlm_config as only cluster configuration dlm: dlm_config_info config fields to unsigned int dlm: rename config to configfs kobject: add kset_type_create_and_add() helper kobject: export generic helper ops dlm: separate dlm lockspaces per net-namespace dlm: add nldlm net-namespace aware UAPI gfs2: separate mount context by net-namespaces Documentation/netlink/specs/nldlm.yaml | 438 ++++++++ drivers/md/md-cluster.c | 3 +- fs/dlm/Makefile | 3 + fs/dlm/config.c | 1291 +++++++++-------------- fs/dlm/config.h | 215 +++- fs/dlm/configfs.c | 882 ++++++++++++++++ fs/dlm/configfs.h | 19 + fs/dlm/debug_fs.c | 24 +- fs/dlm/dir.c | 4 +- fs/dlm/dlm_internal.h | 24 +- fs/dlm/lock.c | 64 +- fs/dlm/lock.h | 3 +- fs/dlm/lockspace.c | 220 ++-- fs/dlm/lockspace.h | 12 +- fs/dlm/lowcomms.c | 525 +++++----- fs/dlm/lowcomms.h | 29 +- fs/dlm/main.c | 5 - fs/dlm/member.c | 36 +- fs/dlm/midcomms.c | 287 ++--- fs/dlm/midcomms.h | 31 +- fs/dlm/netlink2.c | 1330 ++++++++++++++++++++++++ fs/dlm/nldlm-kernel.c | 290 ++++++ fs/dlm/nldlm-kernel.h | 50 + fs/dlm/nldlm.c | 847 +++++++++++++++ fs/dlm/plock.c | 2 +- fs/dlm/rcom.c | 16 +- fs/dlm/rcom.h | 3 +- fs/dlm/recover.c | 17 +- fs/dlm/user.c | 63 +- fs/dlm/user.h | 2 +- fs/gfs2/glock.c | 8 + fs/gfs2/incore.h | 2 + fs/gfs2/lock_dlm.c | 6 +- fs/gfs2/ops_fstype.c | 5 + fs/gfs2/sys.c | 35 +- fs/ocfs2/stack_user.c | 2 +- include/linux/dlm.h | 9 +- include/linux/kobject.h | 10 +- include/uapi/linux/nldlm.h | 153 +++ lib/kobject.c | 65 +- 40 files changed, 5566 insertions(+), 1464 deletions(-) create mode 100644 Documentation/netlink/specs/nldlm.yaml create mode 100644 fs/dlm/configfs.c create mode 100644 fs/dlm/configfs.h create mode 100644 fs/dlm/netlink2.c create mode 100644 fs/dlm/nldlm-kernel.c create mode 100644 fs/dlm/nldlm-kernel.h create mode 100644 fs/dlm/nldlm.c create mode 100644 include/uapi/linux/nldlm.h -- 2.43.0
