block: don't allow splitting of a REQ_NOWAIT bio

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commit 9cea62b2cb upstream.

If we split a bio marked with REQ_NOWAIT, then we can trigger spurious
EAGAIN if constituent parts of that split bio end up failing request
allocations. Parts will complete just fine, but just a single failure
in one of the chained bios will yield an EAGAIN final result for the
parent bio.

Return EAGAIN early if we end up needing to split such a bio, which
allows for saner recovery handling.

Cc: stable@vger.kernel.org # 5.15+
Link: https://github.com/axboe/liburing/issues/766
Reported-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Jens Axboe 2023-01-04 08:52:06 -07:00 • committed by Greg Kroah-Hartman

parent 39a20c4354

commit 6d47e0f6a5

1 changed files with 10 additions and 0 deletions

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block/blk-merge.c

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