Improve block cloning transactions accounting #17431
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Previous dmu_tx_count_clone() was broken, stating that cloning is similar to free. While they might be from some points, cloning is not net-free. It will likely consume space and memory, and unlike free it will do it no matter whether the destination has the blocks or not (usually not, so previous code did nothing). Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc.
behlendorf
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behlendorf
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Jun 13, 2025
Previous dmu_tx_count_clone() was broken, stating that cloning is similar to free. While they might be from some points, cloning is not net-free. It will likely consume space and memory, and unlike free it will do it no matter whether the destination has the blocks or not (usually not, so previous code did nothing). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc. Closes openzfs#17431
behlendorf
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Jun 17, 2025
Previous dmu_tx_count_clone() was broken, stating that cloning is similar to free. While they might be from some points, cloning is not net-free. It will likely consume space and memory, and unlike free it will do it no matter whether the destination has the blocks or not (usually not, so previous code did nothing). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc. Closes #17431
behlendorf
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Jun 17, 2025
Previous dmu_tx_count_clone() was broken, stating that cloning is similar to free. While they might be from some points, cloning is not net-free. It will likely consume space and memory, and unlike free it will do it no matter whether the destination has the blocks or not (usually not, so previous code did nothing). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc. Closes openzfs#17431
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Previous
dmu_tx_count_clone()was broken, stating that cloning is similar to free. While they might be from some points, cloning is not net-free. It will likely consume space and memory, and unlike free it will do it no matter whether the destination has the blocks allocated or not (usually not, so previous code usually did nothing).This still does not account for some resource usage triggered by cloning, in particular BRT updates done by sync thread, but it should be better than nothing, and doing more would be too messy. So lets try this and see how it go.
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