* [PATCH] io_uring: fix short read/write with linked ops
@ 2022-10-03 9:19 David Stevens
2022-10-03 10:35 ` Pavel Begunkov
0 siblings, 1 reply; 3+ messages in thread
From: David Stevens @ 2022-10-03 9:19 UTC (permalink / raw)
To: io-uring; +Cc: Jens Axboe, Pavel Begunkov, David Stevens
From: David Stevens <[email protected]>
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.
Fixes: 227c0c9673d8 ("io_uring: internally retry short reads")
Signed-off-by: David Stevens <[email protected]>
---
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 */
--
2.38.0.rc1.362.ged0d419d3c-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] io_uring: fix short read/write with linked ops
2022-10-03 9:19 [PATCH] io_uring: fix short read/write with linked ops David Stevens
@ 2022-10-03 10:35 ` Pavel Begunkov
2022-10-04 2:17 ` David Stevens
0 siblings, 1 reply; 3+ messages in thread
From: Pavel Begunkov @ 2022-10-03 10:35 UTC (permalink / raw)
To: David Stevens, io-uring; +Cc: Jens Axboe
On 10/3/22 10:19, David Stevens wrote:
> From: David Stevens <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] io_uring: fix short read/write with linked ops
2022-10-03 10:35 ` Pavel Begunkov
@ 2022-10-04 2:17 ` David Stevens
0 siblings, 0 replies; 3+ messages in thread
From: David Stevens @ 2022-10-04 2:17 UTC (permalink / raw)
To: Pavel Begunkov; +Cc: io-uring, Jens Axboe
On Mon, Oct 3, 2022 at 7:40 PM Pavel Begunkov <[email protected]> wrote:
>
> On 10/3/22 10:19, David Stevens wrote:
> > From: David Stevens <[email protected]>
> >
> > 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 <[email protected]>
> > ---
> > 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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-10-03 10:35 ` Pavel Begunkov
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