[PATCH] fcntl: allow to set O_DIRECT flag on pipe

From: Stanislav Kinsburskiy
Date: Tue Dec 15 2015 - 10:59:43 EST


With packetized mode for pipes, it's not possible to set O_DIRECT on pipe file
via sys_fcntl, because of unsupported (by pipes) sanity checks.
Ability to set this flag will be used by CRIU to migrate packetized pipes.

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@xxxxxxxxxxxxx>
---
fs/fcntl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index ee85cd4..4463a87 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -51,7 +51,8 @@ static int setfl(int fd, struct file * filp, unsigned long arg)
if (arg & O_NDELAY)
arg |= O_NONBLOCK;

- if (arg & O_DIRECT) {
+ /* Pipe packetized mode is controlled by O_DIRECT flag */
+ if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
if (!filp->f_mapping || !filp->f_mapping->a_ops ||
!filp->f_mapping->a_ops->direct_IO)
return -EINVAL;

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