Hello, Currently, there are three IDs which are being used to identify a cgroup. 1. cgroup->id 2. cgroupfs 32bit ino 3. cgroupfs 32bit ino + 32bit gen All three IDs are visible to userland through different interfaces. This is very confusing and #1 can't even be resolved to cgroups from userland. A 64bit number is sufficient to identify a cgroup instance uniquely and ino_t is 64bit on all archs except for alpha. There's no reason for three different IDs at all. This patchset updates kernfs so that it supports 64bit ino and associated exportfs operations and unifies the cgroup IDs. * On 64bit ino archs, ino is kernfs node ID which is also the cgroup ID. The ino can be passed directly into open_by_handle_at(2) w/ the new key type FILEID_KERNFS. Backward compatibility is maintained for FILEID_INO32_GEN keys. * On 32bit ino archs, kernfs node ID is still 64bit and the cgroup ID. ino is the low 32bits and gen is the high 32bits. If the high 32bits is zero, open_by_handle_at(2) only matches the ino part of the ID allowing userland to resolve inos to cgroups as long as distinguishing recycled inos isn't necessary. This patchset contains the following 10 patches. 0001-kernfs-fix-ino-wrap-around-detection.patch 0002-writeback-use-ino_t-for-inodes-in-tracepoints.patch 0003-netprio-use-css-ID-instead-of-cgroup-ID.patch 0004-kernfs-use-dumber-locking-for-kernfs_find_and_get_no.patch 0005-kernfs-kernfs_find_and_get_node_by_ino-should-only-l.patch 0006-kernfs-convert-kernfs_node-id-from-union-kernfs_node.patch 0007-kernfs-combine-ino-id-lookup-functions-into-kernfs_f.patch 0008-kernfs-implement-custom-exportfs-ops-and-fid-type.patch 0009-kernfs-use-64bit-inos-if-ino_t-is-64bit.patch 0010-cgroup-use-cgrp-kn-id-as-the-cgroup-ID.patch 0001 is a fix which should be backported through -stable. 0002 and 0003 are prep patches. 0004-0009 make kernfs_node->id a u64 and use it as ino on 64bit ino archs. 0010 replaces cgroup->id with the kernfs node ID. Greg, how do you want to route the patches? We can route 0001-0009 through your tree and the last one through cgroup after pulling in. I'd be happy to route them all too. This patchset is also available in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-unified-cgid diffstat follows. Thanks. fs/kernfs/dir.c | 101 +++++++++++++++++++------------------- fs/kernfs/file.c | 4 - fs/kernfs/inode.c | 4 - fs/kernfs/kernfs-internal.h | 2 fs/kernfs/mount.c | 102 ++++++++++++++++++++++----------------- include/linux/cgroup-defs.h | 17 ------ include/linux/cgroup.h | 26 ++++----- include/linux/exportfs.h | 5 + include/linux/kernfs.h | 57 ++++++++++++++------- include/net/netprio_cgroup.h | 2 include/trace/events/cgroup.h | 6 +- include/trace/events/writeback.h | 92 +++++++++++++++++------------------ kernel/bpf/helpers.c | 2 kernel/bpf/local_storage.c | 2 kernel/cgroup/cgroup.c | 81 ++++++++++-------------------- kernel/trace/blktrace.c | 84 +++++++++++++++++--------------- net/core/filter.c | 4 - net/core/netprio_cgroup.c | 8 +-- 18 files changed, 301 insertions(+), 298 deletions(-) -- tejun
