From 3ba8df92a86aa1044ab59110c640ba413341b9f3 Mon Sep 17 00:00:00 2001 From: Chong Cai Date: Thu, 19 Aug 2021 17:20:21 -0700 Subject: Cache verity dentries Add an LRU cache to cache verity dentries when ref count drop to 0. This way we don't need to hash and verify the previous opened files or directories each time. PiperOrigin-RevId: 391880157 --- pkg/sentry/fsimpl/verity/filesystem.go | 47 +++++++++++----------------------- 1 file changed, 15 insertions(+), 32 deletions(-) (limited to 'pkg/sentry/fsimpl/verity/filesystem.go') diff --git a/pkg/sentry/fsimpl/verity/filesystem.go b/pkg/sentry/fsimpl/verity/filesystem.go index e147d6b07..52d47994d 100644 --- a/pkg/sentry/fsimpl/verity/filesystem.go +++ b/pkg/sentry/fsimpl/verity/filesystem.go @@ -66,40 +66,23 @@ func putDentrySlice(ds *[]*dentry) { dentrySlicePool.Put(ds) } -// renameMuRUnlockAndCheckDrop calls fs.renameMu.RUnlock(), then calls -// dentry.checkDropLocked on all dentries in *ds with fs.renameMu locked for +// renameMuRUnlockAndCheckCaching calls fs.renameMu.RUnlock(), then calls +// dentry.checkCachingLocked on all dentries in *ds with fs.renameMu locked for // writing. // // ds is a pointer-to-pointer since defer evaluates its arguments immediately, // but dentry slices are allocated lazily, and it's much easier to say "defer -// fs.renameMuRUnlockAndCheckDrop(&ds)" than "defer func() { -// fs.renameMuRUnlockAndCheckDrop(ds) }()" to work around this. +// fs.renameMuRUnlockAndCheckCaching(&ds)" than "defer func() { +// fs.renameMuRUnlockAndCheckCaching(ds) }()" to work around this. // +checklocksrelease:fs.renameMu -func (fs *filesystem) renameMuRUnlockAndCheckDrop(ctx context.Context, ds **[]*dentry) { +func (fs *filesystem) renameMuRUnlockAndCheckCaching(ctx context.Context, ds **[]*dentry) { fs.renameMu.RUnlock() if *ds == nil { return } - if len(**ds) != 0 { - fs.renameMu.Lock() - for _, d := range **ds { - d.checkDropLocked(ctx) - } - fs.renameMu.Unlock() - } - putDentrySlice(*ds) -} - -// +checklocksrelease:fs.renameMu -func (fs *filesystem) renameMuUnlockAndCheckDrop(ctx context.Context, ds **[]*dentry) { - if *ds == nil { - fs.renameMu.Unlock() - return - } for _, d := range **ds { - d.checkDropLocked(ctx) + d.checkCachingLocked(ctx, false /* renameMuWriteLocked */) } - fs.renameMu.Unlock() putDentrySlice(*ds) } @@ -700,7 +683,7 @@ func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds } var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return err @@ -712,7 +695,7 @@ func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return nil, err @@ -733,7 +716,7 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) d, err := fs.walkParentDirLocked(ctx, rp, start, &ds) if err != nil { @@ -770,7 +753,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) if rp.Done() { @@ -952,7 +935,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return "", err @@ -982,7 +965,7 @@ func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return linux.Statx{}, err @@ -1028,7 +1011,7 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) if _, err := fs.resolveLocked(ctx, rp, &ds); err != nil { return nil, err } @@ -1039,7 +1022,7 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath func (fs *filesystem) ListXattrAt(ctx context.Context, rp *vfs.ResolvingPath, size uint64) ([]string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return nil, err @@ -1055,7 +1038,7 @@ func (fs *filesystem) ListXattrAt(ctx context.Context, rp *vfs.ResolvingPath, si func (fs *filesystem) GetXattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetXattrOptions) (string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return "", err -- cgit v1.2.3