[PATCH v2 2/2] io_uring: add support for zone-append

[Kanchan Joshi <joshi.k@xxxxxxxxxxx>]

From: Selvakumar S <selvakuma.s1@xxxxxxxxxxx>

For zone-append, block-layer will return zone-relative offset via ret2
of ki_complete interface. Make changes to collect it, and send to
user-space using ceq->flags.
Detect and report early error if zone-append is requested with
fixed-buffers.

Signed-off-by: Selvakumar S <selvakuma.s1@xxxxxxxxxxx>
Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
Signed-off-by: Javier Gonzalez <javier.gonz@xxxxxxxxxxx>
---
 fs/io_uring.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 155f3d8..31a9da58 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -402,6 +402,8 @@ struct io_rw {
 	struct kiocb			kiocb;
 	u64				addr;
 	u64				len;
+	/* zone-relative offset for append, in sectors */
+	u32			append_offset;
 };
 
 struct io_connect {
@@ -541,6 +543,7 @@ enum {
 	REQ_F_NO_FILE_TABLE_BIT,
 	REQ_F_QUEUE_TIMEOUT_BIT,
 	REQ_F_WORK_INITIALIZED_BIT,
+	REQ_F_ZONE_APPEND_BIT,
 
 	/* not a real bit, just to check we're not overflowing the space */
 	__REQ_F_LAST_BIT,
@@ -598,6 +601,8 @@ enum {
 	REQ_F_QUEUE_TIMEOUT	= BIT(REQ_F_QUEUE_TIMEOUT_BIT),
 	/* io_wq_work is initialized */
 	REQ_F_WORK_INITIALIZED	= BIT(REQ_F_WORK_INITIALIZED_BIT),
+	/* to return zone relative offset for zone append*/
+	REQ_F_ZONE_APPEND	= BIT(REQ_F_ZONE_APPEND_BIT),
 };
 
 struct async_poll {
@@ -1745,6 +1750,8 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
 
 		if (req->flags & REQ_F_BUFFER_SELECTED)
 			cflags = io_put_kbuf(req);
+		if (req->flags & REQ_F_ZONE_APPEND)
+			cflags = req->rw.append_offset;
 
 		__io_cqring_fill_event(req, req->result, cflags);
 		(*nr_events)++;
@@ -1943,7 +1950,7 @@ static inline void req_set_fail_links(struct io_kiocb *req)
 		req->flags |= REQ_F_FAIL_LINK;
 }
 
-static void io_complete_rw_common(struct kiocb *kiocb, long res)
+static void io_complete_rw_common(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
 	int cflags = 0;
@@ -1953,8 +1960,14 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res)
 
 	if (res != req->result)
 		req_set_fail_links(req);
+
 	if (req->flags & REQ_F_BUFFER_SELECTED)
 		cflags = io_put_kbuf(req);
+
+	/* use cflags to return zone append completion result */
+	if (req->flags & REQ_F_ZONE_APPEND)
+		cflags = res2;
+
 	__io_cqring_add_event(req, res, cflags);
 }
 
@@ -1962,7 +1975,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
 
-	io_complete_rw_common(kiocb, res);
+	io_complete_rw_common(kiocb, res, res2);
 	io_put_req(req);
 }
 
@@ -1975,6 +1988,9 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
 
 	if (res != req->result)
 		req_set_fail_links(req);
+	if (req->flags & REQ_F_ZONE_APPEND)
+		req->rw.append_offset = res2;
+
 	req->result = res;
 	if (res != -EAGAIN)
 		WRITE_ONCE(req->iopoll_completed, 1);
@@ -2127,6 +2143,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	if (kiocb->ki_flags & IOCB_NOWAIT)
 		req->flags |= REQ_F_NOWAIT;
 
+	if (kiocb->ki_flags & IOCB_ZONE_APPEND)
+		req->flags |= REQ_F_ZONE_APPEND;
+
 	if (force_nonblock)
 		kiocb->ki_flags |= IOCB_NOWAIT;
 
@@ -2409,6 +2428,14 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
 
 	opcode = req->opcode;
 	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
+		/*
+		 * fixed-buffers not supported for zone-append.
+		 * This check can be removed when block-layer starts
+		 * supporting append with iov_iter of bvec type
+		 */
+		if (req->flags == REQ_F_ZONE_APPEND)
+			return -EINVAL;
+
 		*iovec = NULL;
 		return io_import_fixed(req, rw, iter);
 	}
@@ -2704,6 +2731,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
 		req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
 
 	req->result = 0;
+
 	io_size = ret;
 	if (req->flags & REQ_F_LINK_HEAD)
 		req->result = io_size;
-- 
2.7.4