From: Dylan Yudaken <dylany@xxxxxx>
commit d34e1e5b396a0dbaa4a29b7138df662cfb9d8e8e upstream.
Update kiocb->ki_pos at execution time rather than in io_prep_rw().
io_prep_rw() happens before the job is enqueued to a worker and so the
offset might be read multiple times before being executed once.
Ensures that the file position in a set of _linked_ SQEs will be only
obtained after earlier SQEs have completed, and so will include their
incremented file position.
Signed-off-by: Dylan Yudaken <dylany@xxxxxx>
Reviewed-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
io_uring/io_uring.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 14297add8485..d9396cfaa4f3 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2922,14 +2922,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
req->flags |= REQ_F_ISREG;
kiocb->ki_pos = READ_ONCE(sqe->off);
- if (kiocb->ki_pos == -1) {
- if (!(file->f_mode & FMODE_STREAM)) {
- req->flags |= REQ_F_CUR_POS;
- kiocb->ki_pos = file->f_pos;
- } else {
- kiocb->ki_pos = 0;
- }
- }
kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
@@ -3011,6 +3003,20 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
}
}
+static inline void io_kiocb_update_pos(struct io_kiocb *req)
+{
+ struct kiocb *kiocb = &req->rw.kiocb;
+
+ if (kiocb->ki_pos == -1) {
+ if (!(req->file->f_mode & FMODE_STREAM)) {
+ req->flags |= REQ_F_CUR_POS;
+ kiocb->ki_pos = req->file->f_pos;
+ } else {
+ kiocb->ki_pos = 0;
+ }
+ }
+}
+
static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
unsigned int issue_flags)
{
@@ -3566,6 +3572,8 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
return ret ?: -EAGAIN;
}
+ io_kiocb_update_pos(req);
+
ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), req->result);
if (unlikely(ret)) {
kfree(iovec);
@@ -3700,6 +3708,8 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
(req->flags & REQ_F_ISREG))
goto copy_iov;
+ io_kiocb_update_pos(req);
+
ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), req->result);
if (unlikely(ret))
goto out_free;
--
2.39.0
