Daniel Verkamp de198cc9be devices: virtio: block: ignore Discard failures ... Our branch of the 3.18 kernel has FALLOC_FL_PUNCH_HOLE disabled for the ext4 filesystem, which means that systems running that kernel always take the fallback path of writing buffers full of zeroes. This is not necessary for the Discard command, since it is just a hint and is not required to actually zero the blocks. Split the WriteZeroes trait up into a new PunchHole trait, which corresponds to fallocate() with FALLOC_FL_PUNCH_HOLE, and use the new trait to implement the virtio block Discard command. BUG=chromium:896314 TEST=`mkfs.btrfs /dev/vdb` and verify the desired fallocate() is used and no write() calls are issued when inducing a failure Change-Id: I67fd9a132758d8d766531ccca8358c7fe67b0460 Signed-off-by: Daniel Verkamp <dverkamp@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/1286224 Reviewed-by: Dylan Reid <dgreid@chromium.org>		2018-10-19 12:19:41 -07:00
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src	devices: virtio: block: ignore Discard failures	2018-10-19 12:19:41 -07:00
Cargo.toml	qcow: implement WriteZeroes for QcowFile	2018-09-05 01:25:50 -07:00