The first write after file create fails to take the direct IO
(Peer-to-Peer) path and falls back to slower software copy. The function
get_more_block() sets 'create' to 0 after comparing 'unsigned long
fs_startblk = 0' with 'long long (i_size_read(dio->inode) - 1) >>
i_blkbits = 0xfffffffffffff'.
v2: Instead of casting to loff_t check explicitly if i_size > 0
Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@xxxxxxx>
---
fs/direct-io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 3aafb33..7a65a74 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -686,7 +686,8 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio,
* buffer head.
*/
create = dio->op == REQ_OP_WRITE;
- if (dio->flags & DIO_SKIP_HOLES) {
+ if (dio->flags & DIO_SKIP_HOLES &&
+ i_size_read(dio->inode) > 0) {
if (fs_startblk <= ((i_size_read(dio->inode) - 1) >>
i_blkbits))
create = 0;
--
2.7.4
