[PATCH 01/10] io_uring: add support for fallocate()

[Jens Axboe <axboe@xxxxxxxxx>]

This exposes fallocate(2) through io_uring.

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 fs/io_uring.c                 | 29 +++++++++++++++++++++++++++++
 include/uapi/linux/io_uring.h |  1 +
 2 files changed, 30 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9b1833fedc5c..d780477b9a56 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1974,6 +1974,32 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	return 0;
 }
 
+static int io_fallocate(struct io_kiocb *req, struct io_kiocb **nxt,
+			bool force_nonblock)
+{
+	const struct io_uring_sqe *sqe = req->sqe;
+	loff_t offset, len;
+	int ret, mode;
+
+	if (sqe->ioprio || sqe->buf_index || sqe->rw_flags)
+		return -EINVAL;
+
+	/* fallocate always requiring blocking context */
+	if (force_nonblock)
+		return -EAGAIN;
+
+	offset = READ_ONCE(sqe->off);
+	len = READ_ONCE(sqe->addr);
+	mode = READ_ONCE(sqe->len);
+
+	ret = vfs_fallocate(req->file, mode, offset, len);
+	if (ret < 0)
+		req_set_fail_links(req);
+	io_cqring_add_event(req, ret);
+	io_put_req_find_next(req, nxt);
+	return 0;
+}
+
 static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_ring_ctx *ctx = req->ctx;
@@ -2983,6 +3009,9 @@ static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
 	case IORING_OP_ASYNC_CANCEL:
 		ret = io_async_cancel(req, req->sqe, nxt);
 		break;
+	case IORING_OP_FALLOCATE:
+		ret = io_fallocate(req, nxt, force_nonblock);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index a3300e1b9a01..bdbe2b130179 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -76,6 +76,7 @@ enum {
 	IORING_OP_ASYNC_CANCEL,
 	IORING_OP_LINK_TIMEOUT,
 	IORING_OP_CONNECT,
+	IORING_OP_FALLOCATE,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
-- 
2.24.1