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authorAndrei Vagin <avagin@google.com>2020-01-07 23:52:59 -0800
committergVisor bot <gvisor-bot@google.com>2020-01-07 23:54:14 -0800
commita53ac7307abfeb7172e67f48d0a7aaa4b5c3f31e (patch)
treeca5d790509a18bbdb9d76391478e5ac1d7f81239
parente77ad574233b779519a253c6f58197c339e9100a (diff)
fs/splice: don't report a partialResult error if there is no data loss
PiperOrigin-RevId: 288642552
-rw-r--r--pkg/sentry/fs/file.go7
-rw-r--r--pkg/sentry/fs/splice.go5
-rw-r--r--test/syscalls/linux/inotify.cc28
3 files changed, 40 insertions, 0 deletions
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index c0a6e884b..a2f966cb6 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -555,6 +555,10 @@ type lockedWriter struct {
//
// This applies only to Write, not WriteAt.
Offset int64
+
+ // Err contains the first error encountered while copying. This is
+ // useful to determine whether Writer or Reader failed during io.Copy.
+ Err error
}
// Write implements io.Writer.Write.
@@ -590,5 +594,8 @@ func (w *lockedWriter) WriteAt(buf []byte, offset int64) (int, error) {
break
}
}
+ if w.Err == nil {
+ w.Err = err
+ }
return written, err
}
diff --git a/pkg/sentry/fs/splice.go b/pkg/sentry/fs/splice.go
index 311798811..389c330a0 100644
--- a/pkg/sentry/fs/splice.go
+++ b/pkg/sentry/fs/splice.go
@@ -167,6 +167,11 @@ func Splice(ctx context.Context, dst *File, src *File, opts SpliceOpts) (int64,
if !srcPipe && !opts.SrcOffset {
atomic.StoreInt64(&src.offset, src.offset+n)
}
+
+ // Don't report any errors if we have some progress without data loss.
+ if w.Err == nil {
+ err = nil
+ }
}
// Drop locks.
diff --git a/test/syscalls/linux/inotify.cc b/test/syscalls/linux/inotify.cc
index 7384c27dc..59ec9940a 100644
--- a/test/syscalls/linux/inotify.cc
+++ b/test/syscalls/linux/inotify.cc
@@ -1591,6 +1591,34 @@ TEST(Inotify, EpollNoDeadlock) {
}
}
+TEST(Inotify, SpliceEvent) {
+ int pipes[2];
+ ASSERT_THAT(pipe2(pipes, O_NONBLOCK), SyscallSucceeds());
+
+ const TempPath root = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(InotifyInit1(IN_NONBLOCK));
+ const TempPath file1 = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+ root.path(), "some content", TempPath::kDefaultFileMode));
+
+ const FileDescriptor file1_fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(file1.path(), O_RDONLY));
+ const int watcher = ASSERT_NO_ERRNO_AND_VALUE(
+ InotifyAddWatch(fd.get(), file1.path(), IN_ALL_EVENTS));
+
+ char buf;
+ EXPECT_THAT(read(file1_fd.get(), &buf, 1), SyscallSucceeds());
+
+ EXPECT_THAT(splice(fd.get(), nullptr, pipes[1], nullptr,
+ sizeof(struct inotify_event) + 1, SPLICE_F_NONBLOCK),
+ SyscallSucceedsWithValue(sizeof(struct inotify_event)));
+
+ const FileDescriptor read_fd(pipes[0]);
+ const std::vector<Event> events =
+ ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(read_fd.get()));
+ ASSERT_THAT(events, Are({Event(IN_ACCESS, watcher)}));
+}
+
} // namespace
} // namespace testing
} // namespace gvisor