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Javier González authored
When a read is directed to the cache, we risk that the lba has been updated during the time we made the L2P table lookup and the time we are actually reading form the cache. We intentionally not hold the L2P lock not to block other threads. While strict ordering is not a guarantee at this level (unless REQ_FLUSH has been previously issued), we have experience that some databases that have recently implemented direct I/O support, issue metadata reads very close to the writes, without issuing a fsync in the middle. An easy way to support them while they is to make an extra effort and check the L2P map right before reading the cache. Signed-off-by:
Javier González <javier@cnexlabs.com> Signed-off-by:
Matias Bjørling <matias@cnexlabs.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
07698466