From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Add a test to make sure that splice works on the source directory before
using it, and if not automatically switch over to read/write method.
Suggested-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213659
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Changes since v1: https://lore.kernel.org/linux-trace-devel/20220608130527.26e50cba@xxxxxxxxxxxxxxxxxx
- Found that my email client messed with the formatting.
This is just the same patch but should now actually apply.
lib/trace-cmd/trace-recorder.c | 38 ++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/lib/trace-cmd/trace-recorder.c b/lib/trace-cmd/trace-recorder.c
index c83337899098..c7ef13c851d2 100644
--- a/lib/trace-cmd/trace-recorder.c
+++ b/lib/trace-cmd/trace-recorder.c
@@ -220,6 +220,41 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags,
return NULL;
}
+static void verify_splice(const char *file, unsigned *flags)
+{
+ int brass[2];
+ int ret;
+ int fd;
+
+ fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE, 0644);
+ if (fd < 0)
+ return; /* Will fail by the caller too */
+
+ if (pipe(brass) < 0)
+ goto fail_pipe;
+
+ ret = splice(brass[0], NULL, fd, NULL, 0, SPLICE_F_NONBLOCK);
+ if (ret < 0)
+ goto fail_splice;
+
+ out_pipe:
+ close(brass[0]);
+ close(brass[1]);
+ out:
+ close(fd);
+ return;
+
+ fail_pipe:
+ tracecmd_warning("Failed opening pipe, trying read/write");
+ *flags |= TRACECMD_RECORD_NOSPLICE;
+ goto out;
+
+ fail_splice:
+ tracecmd_warning("Failed splice to file, trying read/write");
+ *flags |= TRACECMD_RECORD_NOSPLICE;
+ goto out_pipe;
+}
+
struct tracecmd_recorder *
tracecmd_create_buffer_recorder_fd(int fd, int cpu, unsigned flags, const char *buffer)
{
@@ -233,6 +268,9 @@ __tracecmd_create_buffer_recorder(const char *file, int cpu, unsigned flags,
struct tracecmd_recorder *recorder;
int fd;
+ if (!(flags & TRACECMD_RECORD_NOSPLICE))
+ verify_splice(file, &flags);
+
fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE, 0644);
if (fd < 0)
return NULL;
--
2.35.1
|