From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Andreas Grünbacher reports that on the two filesystems that support
iomap directio, it's possible for splice() to return -EAGAIN (instead of
a short splice) if the pipe being written to has less space available in
its pipe buffers than the length supplied by the calling process.
This is a regression test to check for correct operation.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
.gitignore | 1
src/Makefile | 2 -
src/splice-test.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++
tests/generic/720 | 41 ++++++++++++
tests/generic/720.out | 7 ++
tests/generic/group | 1
6 files changed, 224 insertions(+), 1 deletion(-)
create mode 100644 src/splice-test.c
create mode 100755 tests/generic/720
create mode 100644 tests/generic/720.out
diff --git a/.gitignore b/.gitignore
index b0f96ca0..7e6b7daf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -113,6 +113,7 @@
/src/runas
/src/seek_copy_test
/src/seek_sanity_test
+/src/splice-test
/src/stale_handle
/src/stat_test
/src/swapon
diff --git a/src/Makefile b/src/Makefile
index ce6d8610..b015e78b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -28,7 +28,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
attr-list-by-handle-cursor-test listxattr dio-interleaved t_dir_type \
dio-invalidate-cache stat_test t_encrypted_d_revalidate \
attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \
- fscrypt-crypt-util bulkstat_null_ocount
+ fscrypt-crypt-util bulkstat_null_ocount splice-test
SUBDIRS = log-writes perf
diff --git a/src/splice-test.c b/src/splice-test.c
new file mode 100644
index 00000000..11fb11fa
--- /dev/null
+++ b/src/splice-test.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 RedHat Inc. All Rights Reserved.
+ * Author: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
+ *
+ * Make sure that reading and writing to a pipe via splice.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <err.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <errno.h>
+
+#define SECTOR_SIZE 512
+#define BUFFER_SIZE (150 * SECTOR_SIZE)
+
+void read_from_pipe(int fd, const char *filename, size_t size)
+{
+ char buffer[SECTOR_SIZE];
+ size_t sz;
+ ssize_t ret;
+
+ while (size) {
+ sz = size;
+ if (sz > sizeof buffer)
+ sz = sizeof buffer;
+ ret = read(fd, buffer, sz);
+ if (ret < 0)
+ err(1, "read: %s", filename);
+ if (ret == 0) {
+ fprintf(stderr, "read: %s: unexpected EOF\n", filename);
+ exit(1);
+ }
+ size -= sz;
+ }
+}
+
+void do_splice1(int fd, const char *filename, size_t size)
+{
+ bool retried = false;
+ int pipefd[2];
+
+ if (pipe(pipefd) == -1)
+ err(1, "pipe");
+ while (size) {
+ ssize_t spliced;
+
+ spliced = splice(fd, NULL, pipefd[1], NULL, size, SPLICE_F_MOVE);
+ if (spliced == -1) {
+ if (errno == EAGAIN && !retried) {
+ retried = true;
+ fprintf(stderr, "retrying splice\n");
+ sleep(1);
+ continue;
+ }
+ err(1, "splice");
+ }
+ read_from_pipe(pipefd[0], filename, spliced);
+ size -= spliced;
+ }
+ close(pipefd[0]);
+ close(pipefd[1]);
+}
+
+void do_splice2(int fd, const char *filename, size_t size)
+{
+ bool retried = false;
+ int pipefd[2];
+ int pid;
+
+ if (pipe(pipefd) == -1)
+ err(1, "pipe");
+
+ pid = fork();
+ if (pid == 0) {
+ close(pipefd[1]);
+ read_from_pipe(pipefd[0], filename, size);
+ exit(0);
+ } else {
+ close(pipefd[0]);
+ while (size) {
+ ssize_t spliced;
+
+ spliced = splice(fd, NULL, pipefd[1], NULL, size, SPLICE_F_MOVE);
+ if (spliced == -1) {
+ if (errno == EAGAIN && !retried) {
+ retried = true;
+ fprintf(stderr, "retrying splice\n");
+ sleep(1);
+ continue;
+ }
+ err(1, "splice");
+ }
+ size -= spliced;
+ }
+ close(pipefd[1]);
+ waitpid(pid, NULL, 0);
+ }
+}
+
+void usage(const char *argv0)
+{
+ fprintf(stderr, "USAGE: %s [-rd] {filename}\n", basename(argv0));
+ exit(2);
+}
+
+int main(int argc, char *argv[])
+{
+ void (*do_splice)(int fd, const char *filename, size_t size);
+ const char *filename;
+ char *buffer;
+ int opt, open_flags, fd;
+ ssize_t ret;
+
+ do_splice = do_splice1;
+ open_flags = O_CREAT | O_TRUNC | O_RDWR | O_DIRECT;
+
+ while ((opt = getopt(argc, argv, "rd")) != -1) {
+ switch(opt) {
+ case 'r':
+ do_splice = do_splice2;
+ break;
+ case 'd':
+ open_flags &= ~O_DIRECT;
+ break;
+ default: /* '?' */
+ usage(argv[0]);
+ }
+ }
+
+ if (optind >= argc)
+ usage(argv[0]);
+ filename = argv[optind];
+
+ printf("%s reader %s O_DIRECT\n",
+ do_splice == do_splice1 ? "sequential" : "concurrent",
+ (open_flags & O_DIRECT) ? "with" : "without");
+
+ buffer = aligned_alloc(SECTOR_SIZE, BUFFER_SIZE);
+ if (buffer == NULL)
+ err(1, "aligned_alloc");
+
+ fd = open(filename, open_flags, 0666);
+ if (fd == -1)
+ err(1, "open: %s", filename);
+
+ memset(buffer, 'x', BUFFER_SIZE);
+ ret = write(fd, buffer, BUFFER_SIZE);
+ if (ret < 0)
+ err(1, "write: %s", filename);
+ if (ret != BUFFER_SIZE) {
+ fprintf(stderr, "%s: short write\n", filename);
+ exit(1);
+ }
+
+ ret = lseek(fd, 0, SEEK_SET);
+ if (ret != 0)
+ err(1, "lseek: %s", filename);
+
+ do_splice(fd, filename, BUFFER_SIZE);
+
+ if (unlink(filename) == -1)
+ err(1, "unlink: %s", filename);
+
+ return 0;
+}
diff --git a/tests/generic/720 b/tests/generic/720
new file mode 100755
index 00000000..b7f09c40
--- /dev/null
+++ b/tests/generic/720
@@ -0,0 +1,41 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2019, Oracle and/or its affiliates. All Rights Reserved.
+#
+# FS QA Test No. 720
+#
+# Test using splice() to read from pipes.
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1 # failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+ cd /
+ rm -f $TEST_DIR/a
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+
+# real QA test starts here
+_supported_os Linux
+_supported_fs generic
+_require_test
+
+rm -f $seqres.full
+
+src/splice-test -r $TEST_DIR/a
+src/splice-test -rd $TEST_DIR/a
+src/splice-test $TEST_DIR/a
+src/splice-test -d $TEST_DIR/a
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/720.out b/tests/generic/720.out
new file mode 100644
index 00000000..b0fc9935
--- /dev/null
+++ b/tests/generic/720.out
@@ -0,0 +1,7 @@
+QA output created by 720
+concurrent reader with O_DIRECT
+concurrent reader with O_DIRECT
+concurrent reader without O_DIRECT
+concurrent reader without O_DIRECT
+sequential reader with O_DIRECT
+sequential reader without O_DIRECT
diff --git a/tests/generic/group b/tests/generic/group
index fdb7281f..9b5ec377 100644
--- a/tests/generic/group
+++ b/tests/generic/group
@@ -591,4 +591,5 @@
586 auto quick rw prealloc
587 auto quick rw prealloc
588 auto quick log clone
+720 auto quick rw pipe splice
721 auto quick atime
