From 7a234f736fe0e91824b50631e408bd07b2c0ed31 Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Mon, 30 Sep 2019 18:22:25 -0700 Subject: splice: try another fallback option only if the previous one isn't supported Reported-by: syzbot+bb5ed342be51d39b0cbb@syzkaller.appspotmail.com PiperOrigin-RevId: 272110815 --- pkg/sentry/fs/splice.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'pkg/sentry/fs') diff --git a/pkg/sentry/fs/splice.go b/pkg/sentry/fs/splice.go index b03b7f836..311798811 100644 --- a/pkg/sentry/fs/splice.go +++ b/pkg/sentry/fs/splice.go @@ -139,7 +139,7 @@ func Splice(ctx context.Context, dst *File, src *File, opts SpliceOpts) (int64, // Attempt to do a WriteTo; this is likely the most efficient. n, err := src.FileOperations.WriteTo(ctx, src, w, opts.Length, opts.Dup) - if n == 0 && err != nil && err != syserror.ErrWouldBlock && !opts.Dup { + if n == 0 && err == syserror.ENOSYS && !opts.Dup { // Attempt as a ReadFrom. If a WriteTo, a ReadFrom may also be // more efficient than a copy if buffers are cached or readily // available. (It's unlikely that they can actually be donated). @@ -151,7 +151,7 @@ func Splice(ctx context.Context, dst *File, src *File, opts SpliceOpts) (int64, // if we block at some point, we could lose data. If the source is // not a pipe then reading is not destructive; if the destination // is a regular file, then it is guaranteed not to block writing. - if n == 0 && err != nil && err != syserror.ErrWouldBlock && !opts.Dup && (!dstPipe || !srcPipe) { + if n == 0 && err == syserror.ENOSYS && !opts.Dup && (!dstPipe || !srcPipe) { // Fallback to an in-kernel copy. n, err = io.Copy(w, &io.LimitedReader{ R: r, -- cgit v1.2.3