@@ -1202,7 +1202,8 @@ __releases(fiq->lock)
* the 'sent' flag.
*/
static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
- struct fuse_copy_state *cs, size_t nbytes)
+ struct fuse_copy_state *cs, size_t nbytes,
+ bool nonblock)
{
ssize_t err;
struct fuse_conn *fc = fud->fc;
@@ -1238,7 +1239,7 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
break;
spin_unlock(&fiq->lock);
- if (file->f_flags & O_NONBLOCK)
+ if (nonblock)
return -EAGAIN;
err = wait_event_interruptible_exclusive(fiq->waitq,
!fiq->connected || request_pending(fiq));
@@ -1364,7 +1365,8 @@ static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
fuse_copy_init(&cs, 1, to);
- return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
+ return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to),
+ file->f_flags & O_NONBLOCK);
}
static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
@@ -1388,7 +1390,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
fuse_copy_init(&cs, 1, NULL);
cs.pipebufs = bufs;
cs.pipe = pipe;
- ret = fuse_dev_do_read(fud, in, &cs, len);
+ ret = fuse_dev_do_read(fud, in, &cs, len, true);
if (ret < 0)
goto out;
Otherwise we risk sleeping with the pipe locked for indeterminate lengths of time ‒ since FUSE is usually installed with the fusermount helper suid, given cat > fusedev.c <<^D #define _GNU_SOURCE #include <fcntl.h> #define FUSE_USE_VERSION 30 #include <fuse.h> static void *fop_init(struct fuse_conn_info *conn, struct fuse_config *cfg) { for (;;) splice(3, 0, 4, 0, 128 * 1024 * 1024, 0); } static const struct fuse_operations fops = { .init = fop_init }; int main(int argc, char **argv) { return fuse_main(argc, argv, &fops, NULL); } ^D cc nullsleep.c $(pkg-config fuse3 --cflags --libs) -o nullsleep mkfifo fifo mkdir dir ./nullsleep dir 4>fifo & read -r _ < fifo & sleep 0.1 echo zupa > fifo nullsleep used to sleep in splice and the shell used to enter an uninterruptible sleep in open("fifo"); now the splice returns -EAGAIN and the whole program completes. Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz> --- fs/fuse/dev.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)