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| author | Jens Axboe <axboe@kernel.dk> | 2023-01-04 18:52:06 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-12 14:02:47 +0300 |
| commit | 6d47e0f6a535701134d950db65eb8fe1edf0b575 (patch) | |
| tree | 9bf3878b66fc58ca573ca9780073ea43468823a9 /block | |
| parent | 39a20c4354bee56b647c4eef3e7f0e8d235e122c (diff) | |
| download | linux-6d47e0f6a535701134d950db65eb8fe1edf0b575.tar.xz | |
block: don't allow splitting of a REQ_NOWAIT bio
commit 9cea62b2cbabff8ed46f2df17778b624ad9dd25a 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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-merge.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index ff04e9290715..f46c87ef951d 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -300,6 +300,16 @@ static struct bio *bio_split_rw(struct bio *bio, struct queue_limits *lim, *segs = nsegs; return NULL; split: + /* + * We can't sanely support splitting for a REQ_NOWAIT bio. End it + * with EAGAIN if splitting is required and return an error pointer. + */ + if (bio->bi_opf & REQ_NOWAIT) { + bio->bi_status = BLK_STS_AGAIN; + bio_endio(bio); + return ERR_PTR(-EAGAIN); + } + *segs = nsegs; /* |