metropolis: unify utility packages
One last sweeping rename / reshuffle.
We get rid of //metropolis/node/common and //golibs, unifying them into
a single //metropolis/pkg meta-package.
This is to be documented somwhere properly, but here's the new logic
behind selecting where to place a new library package:
- if it's specific to k8s-on-metropolis, put it in
//metropolis/node/kubernetes/*. This is a self-contained tree that
other paths cannot import from.
- if it's a big new subsystem of the metropolis core, put it in
//metropolis/node/core. This can be imported by anything in
//m/n (eg the Kubernetes code at //m/n/kubernetes
- otherwise, treat it as generic library that's part of the metropolis
project, and put it in //metropolis/pkg. This can be imported by
anything within //metropolis.
This will be followed up by a diff that updates visibility rules.
Test Plan: Pure refactor, CI only.
X-Origin-Diff: phab/D683
GitOrigin-RevId: 883e7f09a7d22d64e966d07bbe839454ed081c79
diff --git a/metropolis/pkg/fsquota/fsquota.go b/metropolis/pkg/fsquota/fsquota.go
new file mode 100644
index 0000000..b1305f8
--- /dev/null
+++ b/metropolis/pkg/fsquota/fsquota.go
@@ -0,0 +1,146 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package fsquota provides a simplified interface to interact with Linux's filesystem qouta API.
+// It only supports setting quotas on directories, not groups or users.
+// Quotas need to be already enabled on the filesystem to be able to use them using this package.
+// See the quotactl package if you intend to use this on a filesystem where quotas need to be
+// enabled manually.
+package fsquota
+
+import (
+ "fmt"
+ "math"
+ "os"
+
+ "golang.org/x/sys/unix"
+
+ "git.monogon.dev/source/nexantic.git/metropolis/pkg/fsquota/fsxattrs"
+ "git.monogon.dev/source/nexantic.git/metropolis/pkg/fsquota/quotactl"
+)
+
+// SetQuota sets the quota of bytes and/or inodes in a given path. To not set a limit, set the
+// corresponding argument to zero. Setting both arguments to zero removes the quota entirely.
+// This function can only be called on an empty directory. It can't be used to create a quota
+// below a directory which already has a quota since Linux doesn't offer hierarchical quotas.
+func SetQuota(path string, maxBytes uint64, maxInodes uint64) error {
+ dir, err := os.Open(path)
+ if err != nil {
+ return err
+ }
+ defer dir.Close()
+ source, err := fsinfoGetSource(dir)
+ if err != nil {
+ return err
+ }
+ var valid uint32
+ if maxBytes > 0 {
+ valid |= quotactl.FlagBLimitsValid
+ }
+ if maxInodes > 0 {
+ valid |= quotactl.FlagILimitsValid
+ }
+
+ attrs, err := fsxattrs.Get(dir)
+ if err != nil {
+ return err
+ }
+
+ var lastID uint32 = attrs.ProjectID
+ if lastID == 0 {
+ // No project/quota exists for this directory, assign a new project quota
+ // TODO(lorenz): This is racy, but the kernel does not support atomically assigning
+ // quotas. So this needs to be added to the kernels setquota interface. Due to the short
+ // time window and infrequent calls this should not be an immediate issue.
+ for {
+ quota, err := quotactl.GetNextQuota(source, quotactl.QuotaTypeProject, lastID)
+ if err == unix.ENOENT || err == unix.ESRCH {
+ // We have enumerated all quotas, nothing exists here
+ break
+ } else if err != nil {
+ return fmt.Errorf("failed to call GetNextQuota: %w", err)
+ }
+ if quota.ID > lastID+1 {
+ // Take the first ID in the quota ID gap
+ lastID++
+ break
+ }
+ lastID++
+ }
+ }
+
+ // If both limits are zero, this is a delete operation, process it as such
+ if maxBytes == 0 && maxInodes == 0 {
+ valid = quotactl.FlagBLimitsValid | quotactl.FlagILimitsValid
+ attrs.ProjectID = 0
+ attrs.Flags &= ^fsxattrs.FlagProjectInherit
+ } else {
+ attrs.ProjectID = lastID
+ attrs.Flags |= fsxattrs.FlagProjectInherit
+ }
+
+ if err := fsxattrs.Set(dir, attrs); err != nil {
+ return err
+ }
+
+ // Always round up to the nearest block size
+ bytesLimitBlocks := uint64(math.Ceil(float64(maxBytes) / float64(1024)))
+
+ return quotactl.SetQuota(source, quotactl.QuotaTypeProject, lastID, "actl.Quota{
+ BHardLimit: bytesLimitBlocks,
+ BSoftLimit: bytesLimitBlocks,
+ IHardLimit: maxInodes,
+ ISoftLimit: maxInodes,
+ Valid: valid,
+ })
+}
+
+type Quota struct {
+ Bytes uint64
+ BytesUsed uint64
+ Inodes uint64
+ InodesUsed uint64
+}
+
+// GetQuota returns the current active quota and its utilization at the given path
+func GetQuota(path string) (*Quota, error) {
+ dir, err := os.Open(path)
+ if err != nil {
+ return nil, err
+ }
+ defer dir.Close()
+ source, err := fsinfoGetSource(dir)
+ if err != nil {
+ return nil, err
+ }
+ attrs, err := fsxattrs.Get(dir)
+ if err != nil {
+ return nil, err
+ }
+ if attrs.ProjectID == 0 {
+ return nil, os.ErrNotExist
+ }
+ quota, err := quotactl.GetQuota(source, quotactl.QuotaTypeProject, attrs.ProjectID)
+ if err != nil {
+ return nil, err
+ }
+ return &Quota{
+ Bytes: quota.BHardLimit * 1024,
+ BytesUsed: quota.CurSpace,
+ Inodes: quota.IHardLimit,
+ InodesUsed: quota.CurInodes,
+ }, nil
+}