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Zach BrownandMark Fasheh
51e8b614e5
scoutfs_item_next() could livelock given the right key and segment key boundaries. This was easiest to trigger with an fio command that wrote a lot of data: fio --filesize=100m --nrfiles=25 --name=100m --numjobs=1 \ --iodepth=1 --ioengine=sync --fallocate=0 \ --rw=write --openfiles=256 \ --directory=$TEST_DIR There were two problems. First, if it found a cached region that didn't contain a next item it would try to read the *end* of the existing cached region instead of trying to populate more items by reading from the key past the existing cached region. This is fixed by incrementing the key to read from after setting it to the end of the cached region. Second, it got totally confused by non-merged but adjacent cached regions. It would find a cached region that contains the search key and try to read from the key after that region, but that key could also be cached and just not merged with its previous region. This is fixed by (duh) having an allocated pos key that we set as we walk through cached regions. It used to always try and read from the search key which was bonkers. With these fixes fio now completes. Signed-off-by: Zach Brown <zab@versity.com>