[PATCH 1/3] fs,block: Introduce IOCB_ZONE_APPEND and direct-io handling

[Kanchan Joshi <joshi.k@xxxxxxxxxxx>]

From: Selvakumar S <selvakuma.s1@xxxxxxxxxxx>

Introduce IOCB_ZONE_APPEND flag, which is set in kiocb->ki_flags for
zone-append. Direct I/O submission path uses this flag to send bio with
append op. And completion path uses the same to return zone-relative
offset to upper layer.

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/block_dev.c     | 19 ++++++++++++++++++-
 include/linux/fs.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 47860e5..4c84b4d0 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -185,6 +185,10 @@ static unsigned int dio_bio_write_op(struct kiocb *iocb)
 	/* avoid the need for a I/O completion work item */
 	if (iocb->ki_flags & IOCB_DSYNC)
 		op |= REQ_FUA;
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (iocb->ki_flags & IOCB_ZONE_APPEND)
+		op |= REQ_OP_ZONE_APPEND | REQ_NOMERGE;
+#endif
 	return op;
 }
 
@@ -295,6 +299,14 @@ static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
 	return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait);
 }
 
+#ifdef CONFIG_BLK_DEV_ZONED
+static inline long blkdev_bio_end_io_append(struct bio *bio)
+{
+	return (bio->bi_iter.bi_sector %
+		blk_queue_zone_sectors(bio->bi_disk->queue)) << SECTOR_SHIFT;
+}
+#endif
+
 static void blkdev_bio_end_io(struct bio *bio)
 {
 	struct blkdev_dio *dio = bio->bi_private;
@@ -307,15 +319,20 @@ static void blkdev_bio_end_io(struct bio *bio)
 		if (!dio->is_sync) {
 			struct kiocb *iocb = dio->iocb;
 			ssize_t ret;
+			long res = 0;
 
 			if (likely(!dio->bio.bi_status)) {
 				ret = dio->size;
 				iocb->ki_pos += ret;
+#ifdef CONFIG_BLK_DEV_ZONED
+				if (iocb->ki_flags & IOCB_ZONE_APPEND)
+					res = blkdev_bio_end_io_append(bio);
+#endif
 			} else {
 				ret = blk_status_to_errno(dio->bio.bi_status);
 			}
 
-			dio->iocb->ki_complete(iocb, ret, 0);
+			dio->iocb->ki_complete(iocb, ret, res);
 			if (dio->multi_bio)
 				bio_put(&dio->bio);
 		} else {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6c4ab4d..dc547b9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -315,6 +315,7 @@ enum rw_hint {
 #define IOCB_SYNC		(1 << 5)
 #define IOCB_WRITE		(1 << 6)
 #define IOCB_NOWAIT		(1 << 7)
+#define IOCB_ZONE_APPEND	(1 << 8)
 
 struct kiocb {
 	struct file		*ki_filp;
-- 
2.7.4