| Message ID | 20221003091923.2096150-1-stevensd@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: fix short read/write with linked ops | expand |
On 10/3/22 10:19, David Stevens wrote: > From: David Stevens <stevensd@chromium.org> > > When continuing a short read/write, account for any completed bytes when > calculating the operation's target length. The operation's actual > accumulated length is fixed up by kiocb_done, and the target and actual > lengths are then compared by __io_complete_rw_common. That function > already propagated the actual length to userspace, but the incorrect > target length was causing it to always cancel linked operations, even > with a successfully completed read/write. The issue looks same as fixed with https://git.kernel.dk/cgit/linux-block/commit/?h=for-6.1/io_uring&id=bf68b5b34311ee57ed40749a1257a30b46127556 Can you check if for-6.1 works for you? git://git.kernel.dk/linux.git for-6.1/io_uring https://git.kernel.dk/cgit/linux-block/log/?h=for-6.1/io_uring > Fixes: 227c0c9673d8 ("io_uring: internally retry short reads") > Signed-off-by: David Stevens <stevensd@chromium.org> > --- > io_uring/rw.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/io_uring/rw.c b/io_uring/rw.c > index 76ebcfebc9a6..aa9967a52dfd 100644 > --- a/io_uring/rw.c > +++ b/io_uring/rw.c > @@ -706,13 +706,14 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > struct kiocb *kiocb = &rw->kiocb; > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > struct io_async_rw *io; > - ssize_t ret, ret2; > + ssize_t ret, ret2, target_len; > loff_t *ppos; > > if (!req_has_async_data(req)) { > ret = io_import_iovec(READ, req, &iovec, s, issue_flags); > if (unlikely(ret < 0)) > return ret; > + target_len = iov_iter_count(&s->iter); > } else { > io = req->async_data; > s = &io->s; > @@ -733,6 +734,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > * need to make this conditional. > */ > iov_iter_restore(&s->iter, &s->iter_state); > + target_len = iov_iter_count(&s->iter) + io->bytes_done; > iovec = NULL; > } > ret = io_rw_init_file(req, FMODE_READ); > @@ -740,7 +742,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > kfree(iovec); > return ret; > } > - req->cqe.res = iov_iter_count(&s->iter); > + req->cqe.res = target_len; > > if (force_nonblock) { > /* If the file doesn't support async, just async punt */ > @@ -850,18 +852,20 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) > struct iovec *iovec; > struct kiocb *kiocb = &rw->kiocb; > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > - ssize_t ret, ret2; > + ssize_t ret, ret2, target_len; > loff_t *ppos; > > if (!req_has_async_data(req)) { > ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); > if (unlikely(ret < 0)) > return ret; > + target_len = iov_iter_count(&s->iter); > } else { > struct io_async_rw *io = req->async_data; > > s = &io->s; > iov_iter_restore(&s->iter, &s->iter_state); > + target_len = iov_iter_count(&s->iter) + io->bytes_done; > iovec = NULL; > } > ret = io_rw_init_file(req, FMODE_WRITE); > @@ -869,7 +873,7 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) > kfree(iovec); > return ret; > } > - req->cqe.res = iov_iter_count(&s->iter); > + req->cqe.res = target_len; > > if (force_nonblock) { > /* If the file doesn't support async, just async punt */
On Mon, Oct 3, 2022 at 7:40 PM Pavel Begunkov <asml.silence@gmail.com> wrote: > > On 10/3/22 10:19, David Stevens wrote: > > From: David Stevens <stevensd@chromium.org> > > > > When continuing a short read/write, account for any completed bytes when > > calculating the operation's target length. The operation's actual > > accumulated length is fixed up by kiocb_done, and the target and actual > > lengths are then compared by __io_complete_rw_common. That function > > already propagated the actual length to userspace, but the incorrect > > target length was causing it to always cancel linked operations, even > > with a successfully completed read/write. > > The issue looks same as fixed with > > https://git.kernel.dk/cgit/linux-block/commit/?h=for-6.1/io_uring&id=bf68b5b34311ee57ed40749a1257a30b46127556 > > Can you check if for-6.1 works for you? > > git://git.kernel.dk/linux.git for-6.1/io_uring > https://git.kernel.dk/cgit/linux-block/log/?h=for-6.1/io_uring Yes, it looks like that fixes the bug I was running into. -David > > Fixes: 227c0c9673d8 ("io_uring: internally retry short reads") > > Signed-off-by: David Stevens <stevensd@chromium.org> > > --- > > io_uring/rw.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/io_uring/rw.c b/io_uring/rw.c > > index 76ebcfebc9a6..aa9967a52dfd 100644 > > --- a/io_uring/rw.c > > +++ b/io_uring/rw.c > > @@ -706,13 +706,14 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > > struct kiocb *kiocb = &rw->kiocb; > > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > > struct io_async_rw *io; > > - ssize_t ret, ret2; > > + ssize_t ret, ret2, target_len; > > loff_t *ppos; > > > > if (!req_has_async_data(req)) { > > ret = io_import_iovec(READ, req, &iovec, s, issue_flags); > > if (unlikely(ret < 0)) > > return ret; > > + target_len = iov_iter_count(&s->iter); > > } else { > > io = req->async_data; > > s = &io->s; > > @@ -733,6 +734,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > > * need to make this conditional. > > */ > > iov_iter_restore(&s->iter, &s->iter_state); > > + target_len = iov_iter_count(&s->iter) + io->bytes_done; > > iovec = NULL; > > } > > ret = io_rw_init_file(req, FMODE_READ); > > @@ -740,7 +742,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) > > kfree(iovec); > > return ret; > > } > > - req->cqe.res = iov_iter_count(&s->iter); > > + req->cqe.res = target_len; > > > > if (force_nonblock) { > > /* If the file doesn't support async, just async punt */ > > @@ -850,18 +852,20 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) > > struct iovec *iovec; > > struct kiocb *kiocb = &rw->kiocb; > > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > > - ssize_t ret, ret2; > > + ssize_t ret, ret2, target_len; > > loff_t *ppos; > > > > if (!req_has_async_data(req)) { > > ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); > > if (unlikely(ret < 0)) > > return ret; > > + target_len = iov_iter_count(&s->iter); > > } else { > > struct io_async_rw *io = req->async_data; > > > > s = &io->s; > > iov_iter_restore(&s->iter, &s->iter_state); > > + target_len = iov_iter_count(&s->iter) + io->bytes_done; > > iovec = NULL; > > } > > ret = io_rw_init_file(req, FMODE_WRITE); > > @@ -869,7 +873,7 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) > > kfree(iovec); > > return ret; > > } > > - req->cqe.res = iov_iter_count(&s->iter); > > + req->cqe.res = target_len; > > > > if (force_nonblock) { > > /* If the file doesn't support async, just async punt */ > > -- > Pavel Begunkov
diff --git a/io_uring/rw.c b/io_uring/rw.c index 76ebcfebc9a6..aa9967a52dfd 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -706,13 +706,14 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) struct kiocb *kiocb = &rw->kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; struct io_async_rw *io; - ssize_t ret, ret2; + ssize_t ret, ret2, target_len; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(READ, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; + target_len = iov_iter_count(&s->iter); } else { io = req->async_data; s = &io->s; @@ -733,6 +734,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) * need to make this conditional. */ iov_iter_restore(&s->iter, &s->iter_state); + target_len = iov_iter_count(&s->iter) + io->bytes_done; iovec = NULL; } ret = io_rw_init_file(req, FMODE_READ); @@ -740,7 +742,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) kfree(iovec); return ret; } - req->cqe.res = iov_iter_count(&s->iter); + req->cqe.res = target_len; if (force_nonblock) { /* If the file doesn't support async, just async punt */ @@ -850,18 +852,20 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) struct iovec *iovec; struct kiocb *kiocb = &rw->kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; - ssize_t ret, ret2; + ssize_t ret, ret2, target_len; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; + target_len = iov_iter_count(&s->iter); } else { struct io_async_rw *io = req->async_data; s = &io->s; iov_iter_restore(&s->iter, &s->iter_state); + target_len = iov_iter_count(&s->iter) + io->bytes_done; iovec = NULL; } ret = io_rw_init_file(req, FMODE_WRITE); @@ -869,7 +873,7 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) kfree(iovec); return ret; } - req->cqe.res = iov_iter_count(&s->iter); + req->cqe.res = target_len; if (force_nonblock) { /* If the file doesn't support async, just async punt */