diff options
| -rw-r--r-- | pkg/sentry/fs/BUILD | 1 | ||||
| -rw-r--r-- | pkg/sentry/fs/mount.go | 2 | ||||
| -rw-r--r-- | pkg/sentry/fs/mount_state.go | 25 | ||||
| -rw-r--r-- | pkg/sentry/kernel/kernel.go | 78 |
4 files changed, 55 insertions, 51 deletions
diff --git a/pkg/sentry/fs/BUILD b/pkg/sentry/fs/BUILD index dda6a0c9f..1742d3a65 100644 --- a/pkg/sentry/fs/BUILD +++ b/pkg/sentry/fs/BUILD @@ -32,7 +32,6 @@ go_library( "mock.go", "mount.go", "mount_overlay.go", - "mount_state.go", "mounts.go", "offset.go", "overlay.go", diff --git a/pkg/sentry/fs/mount.go b/pkg/sentry/fs/mount.go index dd6e64b4c..5cc777bef 100644 --- a/pkg/sentry/fs/mount.go +++ b/pkg/sentry/fs/mount.go @@ -119,7 +119,7 @@ type MountSource struct { // fscache keeps Dirents pinned beyond application references to them. // It must be flushed before kernel.SaveTo. - fscache *DirentCache `state:"nosave"` + fscache *DirentCache // direntRefs is the sum of references on all Dirents in this MountSource. // diff --git a/pkg/sentry/fs/mount_state.go b/pkg/sentry/fs/mount_state.go deleted file mode 100644 index 6344d5160..000000000 --- a/pkg/sentry/fs/mount_state.go +++ /dev/null @@ -1,25 +0,0 @@ -// Copyright 2018 Google LLC -// -// 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 fs - -// afterLoad is invoked by stateify. -// -// Beyond the cache, this method's existence is required to ensure that this -// object is not marked "complete" until all dependent objects are also marked -// "complete". Implementations (e.g. see gofer_state.go) reach into the -// MountSourceOperations through this object, this is necessary on restore. -func (msrc *MountSource) afterLoad() { - msrc.fscache = NewDirentCache(defaultDirentCacheSize) -} diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go index 1cd2653ff..a9994f23b 100644 --- a/pkg/sentry/kernel/kernel.go +++ b/pkg/sentry/kernel/kernel.go @@ -311,7 +311,9 @@ func (k *Kernel) SaveTo(w io.Writer) error { // Clear the dirent cache before saving because Dirents must be Loaded in a // particular order (parents before children), and Loading dirents from a cache // breaks that order. - k.mounts.FlushMountSourceRefs() + if err := k.flushMountSourceRefs(); err != nil { + return err + } // Ensure that all pending asynchronous work is complete: // - inode and mount release @@ -351,39 +353,67 @@ func (k *Kernel) SaveTo(w io.Writer) error { return nil } -func (ts *TaskSet) flushWritesToFiles(ctx context.Context) error { +// flushMountSourceRefs flushes the MountSources for all mounted filesystems +// and open FDs. +func (k *Kernel) flushMountSourceRefs() error { + // Flush all mount sources for currently mounted filesystems. + k.mounts.FlushMountSourceRefs() + + // There may be some open FDs whose filesystems have been unmounted. We + // must flush those as well. + return k.tasks.forEachFDPaused(func(desc descriptor) error { + desc.file.Dirent.Inode.MountSource.FlushDirentRefs() + return nil + }) +} + +// forEachFDPaused applies the given function to each open file descriptor in each +// task. +// +// Precondition: Must be called with the kernel paused. +func (ts *TaskSet) forEachFDPaused(f func(descriptor) error) error { ts.mu.RLock() defer ts.mu.RUnlock() for t := range ts.Root.tids { // We can skip locking Task.mu here since the kernel is paused. - if fdmap := t.fds; fdmap != nil { - for _, desc := range fdmap.files { - if flags := desc.file.Flags(); !flags.Write { - continue - } - if sattr := desc.file.Dirent.Inode.StableAttr; !fs.IsFile(sattr) && !fs.IsDir(sattr) { - continue - } - // Here we need all metadata synced. - syncErr := desc.file.Fsync(ctx, 0, fs.FileMaxOffset, fs.SyncAll) - if err := fs.SaveFileFsyncError(syncErr); err != nil { - name, _ := desc.file.Dirent.FullName(nil /* root */) - // Wrap this error in ErrSaveRejection - // so that it will trigger a save - // error, rather than a panic. This - // also allows us to distinguish Fsync - // errors from state file errors in - // state.Save. - return fs.ErrSaveRejection{ - Err: fmt.Errorf("%q was not sufficiently synced: %v", name, err), - } - } + if t.fds == nil { + continue + } + for _, desc := range t.fds.files { + if err := f(desc); err != nil { + return err } } } return nil } +func (ts *TaskSet) flushWritesToFiles(ctx context.Context) error { + return ts.forEachFDPaused(func(desc descriptor) error { + if flags := desc.file.Flags(); !flags.Write { + return nil + } + if sattr := desc.file.Dirent.Inode.StableAttr; !fs.IsFile(sattr) && !fs.IsDir(sattr) { + return nil + } + // Here we need all metadata synced. + syncErr := desc.file.Fsync(ctx, 0, fs.FileMaxOffset, fs.SyncAll) + if err := fs.SaveFileFsyncError(syncErr); err != nil { + name, _ := desc.file.Dirent.FullName(nil /* root */) + // Wrap this error in ErrSaveRejection + // so that it will trigger a save + // error, rather than a panic. This + // also allows us to distinguish Fsync + // errors from state file errors in + // state.Save. + return fs.ErrSaveRejection{ + Err: fmt.Errorf("%q was not sufficiently synced: %v", name, err), + } + } + return nil + }) +} + // Preconditions: The kernel must be paused. func (k *Kernel) invalidateUnsavableMappings(ctx context.Context) error { invalidated := make(map[*mm.MemoryManager]struct{}) |