Re: [PATCH v2] file-posix: fix cache.direct=on check for zoned block devices

[Stefan Hajnoczi <stefanha@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 1277 bytes --]

On Wed, Jun 17, 2026 at 03:36:58PM +0200, Niklas Cassel wrote:
> For zoned block devices with SWR zones, the order of the writes must be
> maintained to avoid write not at write pointer errors.
> Thus, cache.direct=on must be used to bypass the page cache, since the
> page cache uses write-back caching, where the physical order of the writes
> is not guaranteed.
> 
> There is already a check for cache.direct=on in raw_open_common(),
> however, this check is done before raw_refresh_zoned_limits() has been
> called (which initializes bs->bl.zoned), so it is currently dead code.
> 
> Fix this by moving the check to raw_refresh_zoned_limits(), such that the
> check is done after bs->bl.zoned has been initialized.
> 
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
> Reviewed-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> Fixes: 774c726ceb2a ("block: add zoned BlockDriver check to block layer")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
> Changes since v1:
> -Picked up tags from Damien and Dmitry
> -Modified existing code comment to use plural instead of singular
> 
>  block/file-posix.c | 22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]