Zach Brown 7cf8d01c1b scoutfs: fix super read error race ...

The conversion to reading the super with buffer_head IO caused racing
readers to risk spurious errors.  Clearing uptodate to force device
access could race with a current waking reader.  They could wake and
find uptodate cleared and think that an IO error had occurred.

The buffer_head functions generally require higher level serialization
of this kind of use of the uptodate bit.  We use bh_private as a counter
to ensure that we don't clear uptodate while there are active readers.
We then also use a private buffer_head bit to satisfy batches of waiting
readers with each IO.

Signed-off-by: Zach Brown <zab@versity.com>

2020-02-28 11:34:02 -08:00

kmod

scoutfs: fix super read error race

2020-02-28 11:34:02 -08:00

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