On Mon, Nov 04, 2019 at 03:59:34PM -0800, Tejun Heo wrote: > 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. Sorry for the delay. Feel free to take all of these through your tree, that probably is easiest: Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
