mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Ildar SafarovandAyush Ranjan
236bc0f60a
Mirrors fsimpl/gofer's caching model: each dentry holds one ref on its parent; childMap is a weak map. refs == 0 means cache-eligible; refs == -1 means destroyed. Cached children still hold their parent's ref, so a parent only enters the cache after all its children are gone. Per-dentry cachingMu serializes caching state; fs.cacheMu is held only for LRU list mutations. Eviction re-checks under parent.dirMu, severs from childMap, then destroys, cascading checkCaching up the tree. Cache limit is 1000. Co-authored-by: Ayush Ranjan <[email protected]>
62 lines
1.8 KiB
Go
62 lines
1.8 KiB
Go
// Copyright 2023 The gVisor Authors.
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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 erofs
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import (
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"context"
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"fmt"
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"os"
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"gvisor.dev/gvisor/pkg/erofs"
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"gvisor.dev/gvisor/pkg/refs"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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)
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// afterLoad is called by stateify.
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func (fs *filesystem) afterLoad(ctx context.Context) {
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fdmap := vfs.RestoreFilesystemFDMapFromContext(ctx)
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fd, ok := fdmap[fs.iopts.UniqueID]
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if !ok {
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panic(fmt.Sprintf("no image FD available for filesystem with unique ID %q, map: %#v", fs.iopts.UniqueID, fdmap))
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}
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newImage, err := erofs.OpenImage(os.NewFile(uintptr(fd), "EROFS image file"))
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if err != nil {
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panic(fmt.Sprintf("erofs.OpenImage failed: %v", err))
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}
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if got, want := newImage.SuperBlock(), fs.image.SuperBlock(); got != want {
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panic(fmt.Sprintf("superblock mismatch detected on restore, got %+v, expected %+v", got, want))
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}
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// We need to update the image in place, as there are other pointers
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// pointing to this image as well.
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*fs.image = *newImage
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}
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// saveParent is called by stateify.
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func (d *dentry) saveParent() *dentry {
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return d.parent.Load()
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}
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// loadParent is called by stateify.
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func (d *dentry) loadParent(_ context.Context, parent *dentry) {
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d.parent.Store(parent)
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}
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// afterLoad is called by stateify.
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func (d *dentry) afterLoad(context.Context) {
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if d.refs.Load() != -1 {
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refs.Register(d)
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}
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}
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