From: Dave Chinner <dchinner@xxxxxxxxxx>
So that O_RDONLY open commands (such as from copy_range) do not
block forever waiting on a non-existent writer.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
io/open.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/io/open.c b/io/open.c
index 6ea3e9a2019f..b1d9a0fa317c 100644
--- a/io/open.c
+++ b/io/open.c
@@ -56,6 +56,7 @@ openfile(
struct fs_path *fs_path)
{
struct fs_path *fsp;
+ struct stat st;
int fd;
int oflags;
@@ -79,6 +80,18 @@ openfile(
if (flags & IO_NOFOLLOW)
oflags |= O_NOFOLLOW;
+ /*
+ * if we've been passed a pipe to open, don't block waiting for a
+ * reader or writer to appear. We want to either succeed or error out
+ * immediately.
+ */
+ if (stat(path, &st) < 0 && errno != ENOENT) {
+ perror("stat");
+ return -1;
+ }
+ if (S_ISFIFO(st.st_mode))
+ oflags |= O_NONBLOCK;
+
fd = open(path, oflags, mode);
if (fd < 0) {
if (errno == EISDIR &&
--
2.19.1
