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-rw-r--r--pkg/sentry/fs/gofer/BUILD1
-rw-r--r--pkg/sentry/fs/gofer/cache_policy.go103
-rw-r--r--pkg/sentry/fs/gofer/file.go31
-rw-r--r--pkg/sentry/fs/gofer/fs.go21
-rw-r--r--pkg/sentry/fs/gofer/inode.go28
-rw-r--r--pkg/sentry/fs/gofer/path.go50
-rw-r--r--pkg/sentry/fs/gofer/session.go11
7 files changed, 163 insertions, 82 deletions
diff --git a/pkg/sentry/fs/gofer/BUILD b/pkg/sentry/fs/gofer/BUILD
index ca42b0a54..e6f659c53 100644
--- a/pkg/sentry/fs/gofer/BUILD
+++ b/pkg/sentry/fs/gofer/BUILD
@@ -22,6 +22,7 @@ go_library(
name = "gofer",
srcs = [
"attr.go",
+ "cache_policy.go",
"context_file.go",
"device.go",
"file.go",
diff --git a/pkg/sentry/fs/gofer/cache_policy.go b/pkg/sentry/fs/gofer/cache_policy.go
new file mode 100644
index 000000000..eec8c07cb
--- /dev/null
+++ b/pkg/sentry/fs/gofer/cache_policy.go
@@ -0,0 +1,103 @@
+// Copyright 2018 Google Inc.
+//
+// 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 gofer
+
+import (
+ "fmt"
+
+ "gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+)
+
+// cachePolicy is a 9p cache policy. It has methods that determine what to
+// cache (if anything) for a given inode.
+type cachePolicy int
+
+const (
+ // Cache nothing.
+ cacheNone cachePolicy = iota
+
+ // Use virtual file system cache for everything.
+ cacheAll
+
+ // Use virtual file system cache for everything, but send writes to the
+ // fs agent immediately.
+ cacheAllWritethrough
+)
+
+func parseCachePolicy(policy string) (cachePolicy, error) {
+ switch policy {
+ case "fscache":
+ return cacheAll, nil
+ case "none":
+ return cacheNone, nil
+ case "fscache_writethrough":
+ return cacheAllWritethrough, nil
+ }
+ return cacheNone, fmt.Errorf("unsupported cache mode: %s", policy)
+}
+
+// cacheUAtters determines whether unstable attributes should be cached for the
+// given inode.
+func (cp cachePolicy) cacheUAttrs(inode *fs.Inode) bool {
+ if !fs.IsFile(inode.StableAttr) && !fs.IsDir(inode.StableAttr) {
+ return false
+ }
+ return cp == cacheAll || cp == cacheAllWritethrough
+}
+
+// cacheReaddir determines whether readdir results should be cached.
+func (cp cachePolicy) cacheReaddir() bool {
+ return cp == cacheAll || cp == cacheAllWritethrough
+}
+
+// usePageCache determines whether the page cache should be used for the given
+// inode.
+func (cp cachePolicy) usePageCache(inode *fs.Inode) bool {
+ // Do cached IO for regular files only. Some "character devices" expect
+ // no caching.
+ if !fs.IsFile(inode.StableAttr) {
+ return false
+ }
+ return cp == cacheAll || cp == cacheAllWritethrough
+}
+
+// writeThough indicates whether writes to the file should be synced to the
+// gofer immediately.
+func (cp cachePolicy) writeThrough(inode *fs.Inode) bool {
+ return cp == cacheNone || cp == cacheAllWritethrough
+}
+
+// revalidateDirent indicates that dirents should be revalidated after they are
+// looked up.
+func (cp cachePolicy) revalidateDirent() bool {
+ return cp == cacheNone
+}
+
+// keepDirent indicates that dirents should be kept pinned in the dirent tree
+// even if there are no application references on the file.
+func (cp cachePolicy) keepDirent(inode *fs.Inode) bool {
+ if cp == cacheNone {
+ return false
+ }
+ sattr := inode.StableAttr
+ // NOTE: Only cache files, directories, and symlinks.
+ return fs.IsFile(sattr) || fs.IsDir(sattr) || fs.IsSymlink(sattr)
+}
+
+// cacheNegativeDirents indicates that negative dirents should be held in the
+// dirent tree.
+func (cp cachePolicy) cacheNegativeDirents() bool {
+ return cp == cacheAll || cp == cacheAllWritethrough
+}
diff --git a/pkg/sentry/fs/gofer/file.go b/pkg/sentry/fs/gofer/file.go
index 07c9bf01d..69cee7026 100644
--- a/pkg/sentry/fs/gofer/file.go
+++ b/pkg/sentry/fs/gofer/file.go
@@ -93,7 +93,7 @@ func (f *fileOperations) Readdir(ctx context.Context, file *fs.File, serializer
DirCursor: &f.dirCursor,
}
n, err := fs.DirentReaddir(ctx, file.Dirent, f, root, dirCtx, file.Offset())
- if f.inodeOperations.session().cachePolicy != cacheNone {
+ if f.inodeOperations.session().cachePolicy.cacheUAttrs(file.Dirent.Inode) {
f.inodeOperations.cachingInodeOps.TouchAccessTime(ctx, file.Dirent.Inode)
}
return n, err
@@ -105,7 +105,7 @@ func (f *fileOperations) IterateDir(ctx context.Context, dirCtx *fs.DirCtx, offs
defer f.inodeOperations.readdirMu.Unlock()
// Fetch directory entries if needed.
- if f.inodeOperations.readdirCache == nil || f.inodeOperations.session().cachePolicy == cacheNone {
+ if !f.inodeOperations.session().cachePolicy.cacheReaddir() || f.inodeOperations.readdirCache == nil {
entries, err := f.readdirAll(ctx)
if err != nil {
return offset, err
@@ -183,13 +183,20 @@ func (f *fileOperations) Write(ctx context.Context, file *fs.File, src usermem.I
// Not all remote file systems enforce this so this client does.
return 0, syserror.EISDIR
}
+ cp := f.inodeOperations.session().cachePolicy
+ if cp.usePageCache(file.Dirent.Inode) {
+ n, err := f.inodeOperations.cachingInodeOps.Write(ctx, src, offset)
+ if err != nil {
+ return n, err
+ }
+ if cp.writeThrough(file.Dirent.Inode) {
+ // Write out the file.
+ err = f.inodeOperations.cachingInodeOps.WriteOut(ctx, file.Dirent.Inode)
+ }
+ return n, err
- // Do cached IO for regular files only. Some character devices expect no caching.
- isFile := fs.IsFile(file.Dirent.Inode.StableAttr)
- if f.inodeOperations.session().cachePolicy == cacheNone || !isFile {
- return src.CopyInTo(ctx, f.handles.readWriterAt(ctx, offset))
}
- return f.inodeOperations.cachingInodeOps.Write(ctx, src, offset)
+ return src.CopyInTo(ctx, f.handles.readWriterAt(ctx, offset))
}
// Read implements fs.FileOperations.Read.
@@ -199,12 +206,10 @@ func (f *fileOperations) Read(ctx context.Context, file *fs.File, dst usermem.IO
return 0, syserror.EISDIR
}
- // Do cached IO for regular files only. Some character devices expect no caching.
- isFile := fs.IsFile(file.Dirent.Inode.StableAttr)
- if f.inodeOperations.session().cachePolicy == cacheNone || !isFile {
- return dst.CopyOutFrom(ctx, f.handles.readWriterAt(ctx, offset))
+ if f.inodeOperations.session().cachePolicy.usePageCache(file.Dirent.Inode) {
+ return f.inodeOperations.cachingInodeOps.Read(ctx, file, dst, offset)
}
- return f.inodeOperations.cachingInodeOps.Read(ctx, file, dst, offset)
+ return dst.CopyOutFrom(ctx, f.handles.readWriterAt(ctx, offset))
}
// Fsync implements fs.FileOperations.Fsync.
@@ -243,7 +248,7 @@ func (f *fileOperations) Flush(ctx context.Context, file *fs.File) error {
// ConfigureMMap implements fs.FileOperations.ConfigureMMap.
func (f *fileOperations) ConfigureMMap(ctx context.Context, file *fs.File, opts *memmap.MMapOpts) error {
- if !isFileCachable(f.inodeOperations.session(), file.Dirent.Inode) {
+ if !f.inodeOperations.session().cachePolicy.usePageCache(file.Dirent.Inode) {
return syserror.ENODEV
}
return fsutil.GenericConfigureMMap(file, f.inodeOperations.cachingInodeOps, opts)
diff --git a/pkg/sentry/fs/gofer/fs.go b/pkg/sentry/fs/gofer/fs.go
index a8a3ec19d..e041074d2 100644
--- a/pkg/sentry/fs/gofer/fs.go
+++ b/pkg/sentry/fs/gofer/fs.go
@@ -56,27 +56,6 @@ const (
privateUnixSocketKey = "privateunixsocket"
)
-// cachePolicy is a 9p cache policy.
-type cachePolicy int
-
-const (
- // TODO: fully support cache=none.
- cacheNone cachePolicy = iota
-
- // Use virtual file system cache.
- cacheAll
-)
-
-func parseCachePolicy(policy string) (cachePolicy, error) {
- switch policy {
- case "fscache":
- return cacheAll, nil
- case "none":
- return cacheNone, nil
- }
- return cacheNone, fmt.Errorf("unsupported cache mode: %s", policy)
-}
-
// defaultAname is the default attach name.
const defaultAname = "/"
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index c00da5fec..fa9013b75 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -335,23 +335,15 @@ func (i *inodeOperations) Release(ctx context.Context) {
// Mappable implements fs.InodeOperations.Mappable.
func (i *inodeOperations) Mappable(inode *fs.Inode) memmap.Mappable {
- if i.session().cachePolicy == cacheNone || !fs.IsFile(inode.StableAttr) {
- return nil
+ if i.session().cachePolicy.usePageCache(inode) {
+ return i.cachingInodeOps
}
- return i.cachingInodeOps
-}
-
-func isCachable(session *session, inode *fs.Inode) bool {
- return session.cachePolicy != cacheNone && (fs.IsFile(inode.StableAttr) || fs.IsDir(inode.StableAttr))
-}
-
-func isFileCachable(session *session, inode *fs.Inode) bool {
- return session.cachePolicy != cacheNone && fs.IsFile(inode.StableAttr)
+ return nil
}
// UnstableAttr implements fs.InodeOperations.UnstableAttr.
func (i *inodeOperations) UnstableAttr(ctx context.Context, inode *fs.Inode) (fs.UnstableAttr, error) {
- if isCachable(i.session(), inode) {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
return i.cachingInodeOps.UnstableAttr(ctx, inode)
}
return i.fileState.unstableAttr(ctx)
@@ -433,7 +425,7 @@ func (i *inodeOperations) NonBlockingOpen(ctx context.Context, p fs.PermMask) (*
}
func (i *inodeOperations) getFileDefault(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
- if !isFileCachable(i.session(), d.Inode) {
+ if !i.session().cachePolicy.usePageCache(d.Inode) {
h, err := newHandles(ctx, i.fileState.file, flags)
if err != nil {
return nil, err
@@ -456,7 +448,7 @@ func (i *inodeOperations) getFileDefault(ctx context.Context, d *fs.Dirent, flag
// SetPermissions implements fs.InodeOperations.SetPermissions.
func (i *inodeOperations) SetPermissions(ctx context.Context, inode *fs.Inode, p fs.FilePermissions) bool {
- if isCachable(i.session(), inode) {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
return i.cachingInodeOps.SetPermissions(ctx, inode, p)
}
@@ -473,7 +465,7 @@ func (i *inodeOperations) SetOwner(ctx context.Context, inode *fs.Inode, owner f
return nil
}
- if isCachable(i.session(), inode) {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
return i.cachingInodeOps.SetOwner(ctx, inode, owner)
}
@@ -492,7 +484,7 @@ func (i *inodeOperations) SetOwner(ctx context.Context, inode *fs.Inode, owner f
// SetTimestamps implements fs.InodeOperations.SetTimestamps.
func (i *inodeOperations) SetTimestamps(ctx context.Context, inode *fs.Inode, ts fs.TimeSpec) error {
- if isCachable(i.session(), inode) {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
return i.cachingInodeOps.SetTimestamps(ctx, inode, ts)
}
@@ -502,7 +494,7 @@ func (i *inodeOperations) SetTimestamps(ctx context.Context, inode *fs.Inode, ts
// Truncate implements fs.InodeOperations.Truncate.
func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length int64) error {
// This can only be called for files anyway.
- if isFileCachable(i.session(), inode) {
+ if i.session().cachePolicy.usePageCache(inode) {
return i.cachingInodeOps.Truncate(ctx, inode, length)
}
@@ -511,7 +503,7 @@ func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length
// WriteOut implements fs.InodeOperations.WriteOut.
func (i *inodeOperations) WriteOut(ctx context.Context, inode *fs.Inode) error {
- if !isCachable(i.session(), inode) {
+ if !i.session().cachePolicy.cacheUAttrs(inode) {
return nil
}
diff --git a/pkg/sentry/fs/gofer/path.go b/pkg/sentry/fs/gofer/path.go
index 6c4c2eed9..e78172bda 100644
--- a/pkg/sentry/fs/gofer/path.go
+++ b/pkg/sentry/fs/gofer/path.go
@@ -29,7 +29,7 @@ import (
// Lookup loads an Inode at name into a Dirent based on the session's cache
// policy.
func (i *inodeOperations) Lookup(ctx context.Context, dir *fs.Inode, name string) (*fs.Dirent, error) {
- if i.session().cachePolicy != cacheNone {
+ if i.session().cachePolicy.cacheReaddir() {
// Check to see if we have readdirCache that indicates the
// child does not exist. Avoid holding readdirMu longer than
// we need to.
@@ -46,7 +46,7 @@ func (i *inodeOperations) Lookup(ctx context.Context, dir *fs.Inode, name string
qids, newFile, mask, p9attr, err := i.fileState.file.walkGetAttr(ctx, []string{name})
if err != nil {
if err == syscall.ENOENT {
- if i.session().cachePolicy != cacheNone {
+ if i.session().cachePolicy.cacheNegativeDirents() {
// Return a negative Dirent. It will stay cached until something
// is created over it.
return fs.NewNegativeDirent(name), nil
@@ -95,7 +95,7 @@ func (i *inodeOperations) Create(ctx context.Context, dir *fs.Inode, name string
return nil, err
}
- i.touchModificationTime(ctx)
+ i.touchModificationTime(ctx, dir)
// Get the attributes of the file.
qid, mask, p9attr, err := getattr(ctx, newFile)
@@ -124,7 +124,7 @@ func (i *inodeOperations) Create(ctx context.Context, dir *fs.Inode, name string
File: newFile,
Host: hostFile,
}
- if isFileCachable(iops.session(), d.Inode) {
+ if iops.session().cachePolicy.usePageCache(d.Inode) {
iops.fileState.setHandlesForCachedIO(flags, h)
}
return NewFile(ctx, d, flags, iops, h), nil
@@ -136,12 +136,12 @@ func (i *inodeOperations) CreateLink(ctx context.Context, dir *fs.Inode, oldname
if _, err := i.fileState.file.symlink(ctx, oldname, newname, p9.UID(owner.UID), p9.GID(owner.GID)); err != nil {
return err
}
- i.touchModificationTime(ctx)
+ i.touchModificationTime(ctx, dir)
return nil
}
// CreateHardLink implements InodeOperations.CreateHardLink.
-func (i *inodeOperations) CreateHardLink(ctx context.Context, _ *fs.Inode, target *fs.Inode, newName string) error {
+func (i *inodeOperations) CreateHardLink(ctx context.Context, inode *fs.Inode, target *fs.Inode, newName string) error {
targetOpts, ok := target.InodeOperations.(*inodeOperations)
if !ok {
return syscall.EXDEV
@@ -150,11 +150,11 @@ func (i *inodeOperations) CreateHardLink(ctx context.Context, _ *fs.Inode, targe
if err := i.fileState.file.link(ctx, &targetOpts.fileState.file, newName); err != nil {
return err
}
- if i.session().cachePolicy == cacheAll {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
// Increase link count.
targetOpts.cachingInodeOps.IncLinks(ctx)
}
- i.touchModificationTime(ctx)
+ i.touchModificationTime(ctx, inode)
return nil
}
@@ -164,10 +164,11 @@ func (i *inodeOperations) CreateDirectory(ctx context.Context, dir *fs.Inode, s
if _, err := i.fileState.file.mkdir(ctx, s, p9.FileMode(perm.LinuxMode()), p9.UID(owner.UID), p9.GID(owner.GID)); err != nil {
return err
}
- if i.session().cachePolicy == cacheAll {
+ if i.session().cachePolicy.cacheUAttrs(dir) {
// Increase link count.
i.cachingInodeOps.IncLinks(ctx)
-
+ }
+ if i.session().cachePolicy.cacheReaddir() {
// Invalidate readdir cache.
i.markDirectoryDirty()
}
@@ -202,7 +203,7 @@ func (i *inodeOperations) Bind(ctx context.Context, dir *fs.Inode, name string,
// We're not going to use this file.
hostFile.Close()
- i.touchModificationTime(ctx)
+ i.touchModificationTime(ctx, dir)
// Get the attributes of the file to create inode key.
qid, _, attr, err := getattr(ctx, newFile)
@@ -254,7 +255,7 @@ func (i *inodeOperations) Remove(ctx context.Context, dir *fs.Inode, name string
if removeSocket {
i.session().endpoints.remove(key)
}
- i.touchModificationTime(ctx)
+ i.touchModificationTime(ctx, dir)
return nil
}
@@ -265,10 +266,11 @@ func (i *inodeOperations) RemoveDirectory(ctx context.Context, dir *fs.Inode, na
if err := i.fileState.file.unlinkAt(ctx, name, 0x200); err != nil {
return err
}
- if i.session().cachePolicy == cacheAll {
+ if i.session().cachePolicy.cacheUAttrs(dir) {
// Decrease link count and updates atime.
i.cachingInodeOps.DecLinks(ctx)
-
+ }
+ if i.session().cachePolicy.cacheReaddir() {
// Invalidate readdir cache.
i.markDirectoryDirty()
}
@@ -294,14 +296,17 @@ func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldNa
return err
}
- // Update cached state.
- if i.session().cachePolicy == cacheAll {
- // Is the renamed entity a directory? Fix link counts.
- if fs.IsDir(i.fileState.sattr) {
+ // Is the renamed entity a directory? Fix link counts.
+ if fs.IsDir(i.fileState.sattr) {
+ // Update cached state.
+ if i.session().cachePolicy.cacheUAttrs(oldParent) {
oldParentInodeOperations.cachingInodeOps.DecLinks(ctx)
+ }
+ if i.session().cachePolicy.cacheUAttrs(newParent) {
newParentInodeOperations.cachingInodeOps.IncLinks(ctx)
}
-
+ }
+ if i.session().cachePolicy.cacheReaddir() {
// Mark old directory dirty.
oldParentInodeOperations.markDirectoryDirty()
if oldParent != newParent {
@@ -312,10 +317,11 @@ func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldNa
return nil
}
-func (i *inodeOperations) touchModificationTime(ctx context.Context) {
- if i.session().cachePolicy == cacheAll {
+func (i *inodeOperations) touchModificationTime(ctx context.Context, inode *fs.Inode) {
+ if i.session().cachePolicy.cacheUAttrs(inode) {
i.cachingInodeOps.TouchModificationTime(ctx)
-
+ }
+ if i.session().cachePolicy.cacheReaddir() {
// Invalidate readdir cache.
i.markDirectoryDirty()
}
diff --git a/pkg/sentry/fs/gofer/session.go b/pkg/sentry/fs/gofer/session.go
index baf00d8e7..21dc5e08d 100644
--- a/pkg/sentry/fs/gofer/session.go
+++ b/pkg/sentry/fs/gofer/session.go
@@ -122,17 +122,12 @@ func (s *session) Destroy() {
// Revalidate returns true if the cache policy is does not allow for VFS caching.
func (s *session) Revalidate(*fs.Dirent) bool {
- return s.cachePolicy == cacheNone
+ return s.cachePolicy.revalidateDirent()
}
// TakeRefs takes an extra reference on dirent if possible.
-func (s *session) Keep(dirent *fs.Dirent) bool {
- sattr := dirent.Inode.StableAttr
- if s.cachePolicy == cacheNone {
- return false
- }
- // NOTE: Only cache files, directories, and symlinks.
- return fs.IsFile(sattr) || fs.IsDir(sattr) || fs.IsSymlink(sattr)
+func (s *session) Keep(d *fs.Dirent) bool {
+ return s.cachePolicy.keepDirent(d.Inode)
}
// ResetInodeMappings implements fs.MountSourceOperations.ResetInodeMappings.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 10:17:52 +0000