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| author |   Pavel Begunkov <asml.silence@gmail.com> | 2022-09-09 12:11:49 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-09-09 08:57:57 -0600 |
| commit | 4d9cb92ca41dd8e905a4569ceba4716c2f39c75a (patch) | |
| tree | 3dca38b9e851554c5d33366e191570c4b1c2de17 /io_uring | |
| parent | io_uring/net: copy addr for zc on POLL_FIRST (diff) | |
| download | linux-dev-4d9cb92ca41dd8e905a4569ceba4716c2f39c75a.tar.xz linux-dev-4d9cb92ca41dd8e905a4569ceba4716c2f39c75a.zip | |
io_uring/rw: fix short rw error handling
We have a couple of problems, first reports of unexpected link breakage
for reads when cqe->res indicates that the IO was done in full. The
reason here is partial IO with retries.
TL;DR; we compare the result in __io_complete_rw_common() against
req->cqe.res, but req->cqe.res doesn't store the full length but rather
the length left to be done. So, when we pass the full corrected result
via kiocb_done() -> __io_complete_rw_common(), it fails.
The second problem is that we don't try to correct res in
io_complete_rw(), which, for instance, might be a problem for O_DIRECT
but when a prefix of data was cached in the page cache. We also
definitely don't want to pass a corrected result into io_rw_done().
The fix here is to leave __io_complete_rw_common() alone, always pass
not corrected result into it and fix it up as the last step just before
actually finishing the I/O.
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://github.com/axboe/liburing/issues/643
Reported-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/rw.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/io_uring/rw.c b/io_uring/rw.c index 1babd77da79c..1e18a44adcf5 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -206,6 +206,20 @@ static bool __io_complete_rw_common(struct io_kiocb *req, long res) return false; } +static inline unsigned io_fixup_rw_res(struct io_kiocb *req, unsigned res) +{ + struct io_async_rw *io = req->async_data; + + /* add previously done IO, if any */ + if (req_has_async_data(req) && io->bytes_done > 0) { + if (res < 0) + res = io->bytes_done; + else + res += io->bytes_done; + } + return res; +} + static void io_complete_rw(struct kiocb *kiocb, long res) { struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); @@ -213,7 +227,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res) if (__io_complete_rw_common(req, res)) return; - io_req_set_res(req, res, 0); + io_req_set_res(req, io_fixup_rw_res(req, res), 0); req->io_task_work.func = io_req_task_complete; io_req_task_work_add(req); } @@ -240,22 +254,14 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) static int kiocb_done(struct io_kiocb *req, ssize_t ret, unsigned int issue_flags) { - struct io_async_rw *io = req->async_data; struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); - - /* add previously done IO, if any */ - if (req_has_async_data(req) && io->bytes_done > 0) { - if (ret < 0) - ret = io->bytes_done; - else - ret += io->bytes_done; - } + unsigned final_ret = io_fixup_rw_res(req, ret); if (req->flags & REQ_F_CUR_POS) req->file->f_pos = rw->kiocb.ki_pos; if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { if (!__io_complete_rw_common(req, ret)) { - io_req_set_res(req, req->cqe.res, + io_req_set_res(req, final_ret, io_put_kbuf(req, issue_flags)); return IOU_OK; } @@ -268,7 +274,7 @@ static int kiocb_done(struct io_kiocb *req, ssize_t ret, if (io_resubmit_prep(req)) io_req_task_queue_reissue(req); else - io_req_task_queue_fail(req, ret); + io_req_task_queue_fail(req, final_ret); } return IOU_ISSUE_SKIP_COMPLETE; } |