On 12/12/19 11:09 PM, Naohiro Aota wrote:
Tree manipulating operations like merging nodes often release once-allocated tree nodes. Btrfs cleans such nodes so that pages in the node are not uselessly written out. On HMZONED drives, however, such optimization blocks the following IOs as the cancellation of the write out of the freed blocks breaks the sequential write sequence expected by the device. This patch introduces a list of clean and unwritten extent buffers that have been released in a transaction. Btrfs redirty the buffer so that btree_write_cache_pages() can send proper bios to the devices. Besides it clears the entire content of the extent buffer not to confuse raw block scanners e.g. btrfsck. By clearing the content, csum_dirty_buffer() complains about bytenr mismatch, so avoid the checking and checksum using newly introduced buffer flag EXTENT_BUFFER_NO_CHECK. Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Thanks, Josef
