READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.
Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This debug statement was never meant to go into the upstream release,
kill it off before it ends up in a release. It was just part of the
testing for the initial version of the patch.
Fixes: 2ec33a6c3c ("io_uring/rw: ensure kiocb_end_write() is always called")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A previous commit moved the notifications and end-write handling, but
it is now missing a few spots where we also want to call both of those.
Without that, we can potentially be missing file notifications, and
more importantly, have an imbalance in the super_block writers sem
accounting.
Fixes: b000145e99 ("io_uring/rw: defer fsnotify calls to task context")
Reported-by: Dave Chinner <david@fromorbit.com>
Link: https://lore.kernel.org/all/20221010050319.GC2703033@dread.disaster.area/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This fixes the shadowing of the outer variable rw in the function
io_write(). No issue is caused by this, but let's silence the shadowing
warning anyway.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Link: https://lore.kernel.org/r/20221010234330.244244-1-shr@devkernel.io
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->cqe.res is set in io_read() to the amount of bytes left to be done,
which is used to figure out whether to fail a read or not. However,
io_read() may do another without returning, and we stash the previous
value into ->bytes_done but forget to update cqe.res. Then we ask a read
to do strictly less than cqe.res but expect the return to be exactly
cqe.res.
Fix the bug by updating cqe.res for retries.
Cc: stable@vger.kernel.org
Reported-and-Tested-by: Beld Zhang <beldzhang@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3a1088440c7be98e5800267af922a67da0ef9f13.1664235732.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In commit 934447a603 ("io_uring: do not recycle buffer in READV") a
temporary fix was put in io_kbuf_recycle to simply never recycle READV
buffers.
Instead of that, rather treat READV with REQ_F_BUFFER_SELECTED the same as
a READ with REQ_F_BUFFER_SELECTED. Since READV requires iov_len of 1 they
are essentially the same.
In order to do this inside io_prep_rw() add some validation to check that
it is in fact only length 1, and also extract the length of the buffer at
prep time.
This allows removal of the io_iov_buffer_select codepaths as they are only
used from the READV op.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220907165152.994979-1-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need the poll_flags to know how to poll for the IO, and we should
have the batch structure in preparation for supporting batched
completions with iopoll.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After the addition of iopoll support for passthrough, there's a bit of
a mixup here. Clean it up and get rid of the casting for the passthrough
command type.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Put this up in the same way as iopoll is done for regular read/write IO.
Make place for storing a cookie into struct io_uring_cmd on submission.
Perform the completion using the ->uring_cmd_iopoll handler.
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20220823161443.49436-3-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Kernel test robot reports that we test negativity of an unsigned in
io_fixup_rw_res() after a recent change, which masks error codes and
messes up the return value in case I/O is re-retried and failed with
an error.
Fixes: 4d9cb92ca4 ("io_uring/rw: fix short rw error handling")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9754a0970af1861e7865f9014f735c70dc60bf79.1663071587.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
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Merge tag 'io_uring-6.0-2022-08-13' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
- Regression fix for this merge window, fixing a wrong order of
arguments for io_req_set_res() for passthru (Dylan)
- Fix for the audit code leaking context memory (Peilin)
- Ensure that provided buffers are memcg accounted (Pavel)
- Correctly handle short zero-copy sends (Pavel)
- Sparse warning fixes for the recvmsg multishot command (Dylan)
- Error handling fix for passthru (Anuj)
- Remove randomization of struct kiocb fields, to avoid it growing in
size if re-arranged in such a fashion that it grows more holes or
padding (Keith, Linus)
- Small series improving type safety of the sqe fields (Stefan)
* tag 'io_uring-6.0-2022-08-13' of git://git.kernel.dk/linux-block:
io_uring: add missing BUILD_BUG_ON() checks for new io_uring_sqe fields
io_uring: make io_kiocb_to_cmd() typesafe
fs: don't randomize struct kiocb fields
io_uring: consistently make use of io_notif_to_data()
io_uring: fix error handling for io_uring_cmd
io_uring: fix io_recvmsg_prep_multishot sparse warnings
io_uring/net: send retry for zerocopy
io_uring: mem-account pbuf buckets
audit, io_uring, io-wq: Fix memory leak in io_sq_thread() and io_wqe_worker()
io_uring: pass correct parameters to io_req_set_res
One of the goals is to reduce the overhead of using ->read_iter()
and ->write_iter() instead of ->read()/->write(); new_sync_{read,write}()
has a surprising amount of overhead, in particular inside iocb_flags().
That's why the beginning of the series is in this pile; it's not directly
iov_iter-related, but it's a part of the same work...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs iov_iter updates from Al Viro:
"Part 1 - isolated cleanups and optimizations.
One of the goals is to reduce the overhead of using ->read_iter() and
->write_iter() instead of ->read()/->write().
new_sync_{read,write}() has a surprising amount of overhead, in
particular inside iocb_flags(). That's the explanation for the
beginning of the series is in this pile; it's not directly
iov_iter-related, but it's a part of the same work..."
* tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
first_iovec_segment(): just return address
iov_iter: massage calling conventions for first_{iovec,bvec}_segment()
iov_iter: first_{iovec,bvec}_segment() - simplify a bit
iov_iter: lift dealing with maxpages out of first_{iovec,bvec}_segment()
iov_iter_get_pages{,_alloc}(): cap the maxsize with MAX_RW_COUNT
iov_iter_bvec_advance(): don't bother with bvec_iter
copy_page_{to,from}_iter(): switch iovec variants to generic
keep iocb_flags() result cached in struct file
iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC
struct file: use anonymous union member for rcuhead and llist
btrfs: use IOMAP_DIO_NOSYNC
teach iomap_dio_rw() to suppress dsync
No need of likely/unlikely on calls of check_copy_size()
This adds the io_uring_short_write tracepoint to io_uring. A short write
is issued if not all pages that are required for a write are in the page
cache and the async buffered writes have to return EAGAIN.
Signed-off-by: Stefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20220616212221.2024518-13-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is actually an older issue, but we never used to hit the -EAGAIN
path before having done sb_start_write(). Make sure that we always call
kiocb_end_write() if we need to retry the write, so that we keep the
calls to sb_start_write() etc balanced.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This enables the async buffered writes for the filesystems that support
async buffered writes in io-uring. Buffered writes are enabled for
blocks that are already in the page cache or can be acquired with noio.
Signed-off-by: Stefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20220616212221.2024518-12-shr@fb.com
[axboe: adapt to 5.20 branch]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're offloading requests directly to io-wq because IOSQE_ASYNC was
set in the sqe, we can miss hashing writes appropriately because we
haven't set REQ_F_ISREG yet. This can cause a performance regression
with buffered writes, as io-wq then no longer correctly serializes writes
to that file.
Ensure that we set the flags in io_prep_async_work(), which will cause
the io-wq work item to be hashed appropriately.
Fixes: 584b0180f0 ("io_uring: move read/write file prep state into actual opcode handler")
Link: https://lore.kernel.org/io-uring/20220608080054.GB22428@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This optimisation has some built in assumptions that make it easy to
introduce bugs. It also does not have clear wins that make it worth keeping.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-2-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_issue_sqe() from the io_uring core knows how to complete requests
based on the returned error code, we can delegate io_read()/io_write()
completion to it. Make kiocb_done() to return the right completion
code and propagate it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/32ef005b45d23bf6b5e6837740dc0331bb051bd4.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
