On 12/21/20 10:49 PM, Naohiro Aota wrote:
If more than one IO is issued for one file extent, these IO can be written
to separate regions on a device. Since we cannot map one file extent to
such a separate area, we need to follow the "one IO == one ordered extent"
rule.
The Normal buffered, uncompressed, not pre-allocated write path (used by
cow_file_range()) sometimes does not follow this rule. It can write a part
of an ordered extent when specified a region to write e.g., when its
called from fdatasync().
Introduces a dedicated (uncompressed buffered) data write path for ZONED
mode. This write path will CoW the region and write it at once.
Signed-off-by: Naohiro Aota <naohiro.a...@wdc.com>
This means we'll write one page at a time, no coalescing of data pages. I'm not
the one with zoned devices in production, but it might be worth fixing this in
the future so you're not generating a billion bio's for large sequential data areas.
Reviewed-by: Josef Bacik <jo...@toxicpanda.com>
Thanks,
Josef
