78 lines
2.5 KiB
Go
78 lines
2.5 KiB
Go
// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fs
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import (
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"fmt"
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"syscall"
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"gvisor.googlesource.com/gvisor/pkg/log"
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)
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// SaveInodeMappings saves a mapping of path -> inode ID for every
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// user-reachable Dirent.
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//
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// The entire kernel must be frozen to call this, and filesystem state must not
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// change between SaveInodeMappings and state.Save, otherwise the saved state
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// of any MountSource may be incoherent.
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func SaveInodeMappings() {
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mountsSeen := make(map[*MountSource]struct{})
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for dirent := range allDirents.dirents {
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if _, ok := mountsSeen[dirent.Inode.MountSource]; !ok {
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dirent.Inode.MountSource.ResetInodeMappings()
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mountsSeen[dirent.Inode.MountSource] = struct{}{}
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}
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}
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for dirent := range allDirents.dirents {
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if dirent.Inode != nil {
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// We cannot trust the root provided in the mount due
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// to the overlay. We can trust the overlay to delegate
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// SaveInodeMappings to the right underlying
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// filesystems, though.
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root := dirent
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for !root.mounted && root.parent != nil {
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root = root.parent
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}
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// Add the mapping.
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n, reachable := dirent.FullName(root)
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if !reachable {
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// Something has gone seriously wrong if we can't reach our root.
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panic(fmt.Sprintf("Unreachable root on dirent file %s", n))
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}
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dirent.Inode.MountSource.SaveInodeMapping(dirent.Inode, n)
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}
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}
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}
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// SaveFileFsyncError converts an fs.File.Fsync error to an error that
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// indicates that the fs.File was not synced sufficiently to be saved.
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func SaveFileFsyncError(err error) error {
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switch err {
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case nil:
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// We succeeded, everything is great.
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return nil
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case syscall.EBADF, syscall.EINVAL, syscall.EROFS, syscall.ENOSYS, syscall.EPERM:
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// These errors mean that the underlying node might not be syncable,
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// which we expect to be reported as such even from the gofer.
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log.Infof("failed to sync during save: %v", err)
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return nil
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default:
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// We failed in some way that indicates potential data loss.
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return fmt.Errorf("failed to sync: %v, data loss may occur", err)
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}
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}
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