From d34e1e5b396a0dbaa4a29b7138df662cfb9d8e8e Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Tue, 22 Feb 2022 02:55:02 -0800 Subject: io_uring: update kiocb->ki_pos at execution time 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 Reviewed-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index d9c0fd042f17..d0f3e084da16 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3020,14 +3020,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT; 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_flags = iocb_flags(file); ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); if (unlikely(ret)) @@ -3094,6 +3086,20 @@ 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 io_kiocb *req, ssize_t ret, unsigned int issue_flags) { @@ -3682,6 +3688,8 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) kiocb->ki_flags &= ~IOCB_NOWAIT; } + io_kiocb_update_pos(req); + ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), req->result); if (unlikely(ret)) { kfree(iovec); @@ -3811,6 +3819,8 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) kiocb->ki_flags &= ~IOCB_NOWAIT; } + io_kiocb_update_pos(req); + ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), req->result); if (unlikely(ret)) goto out_free; -- cgit v1.2.3