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

[Kanchan Joshi]

From: Selvakumar S <selvakuma...@samsung.com>

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...@samsung.com>
Signed-off-by: Kanchan Joshi <josh...@samsung.com>
Signed-off-by: Nitesh Shetty <nj.she...@samsung.com>
Signed-off-by: Javier Gonzalez <javier.g...@samsung.com>
---
 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