Re: [PATCH] md: remove REQ_NOWAIT support
"yu kuai" <[email protected]>
| Newsgroups | gmane.linux.raid,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
在 2026/6/28 22:27, Abd-Alrhman Masalkhi 写道:
> REQ_NOWAIT support in md is fundamentally incomplete. While reads can
> avoid some blocking paths, write requests can still encounter cases
> where one mirror succeeds while another returns -EAGAIN. At that point
> md cannot distinguish queue pressure from a real device failure, so it
> can neither record a bad block nor safely retry the write without
> REQ_NOWAIT, leaving mirrors with divergent data.
>
> Rather than continue advertising REQ_NOWAIT support that cannot be
> implemented correctly, remove it from md and its raid personalities.
> This simplifies the waiting paths and avoids exposing incorrect
> non-blocking semantics.
>
> Fixes: bf2c411bb1cf ("md: raid456 add nowait support")
> Fixes: c9aa889b035f ("md: raid10 add nowait support")
> Fixes: 5aa705039c4f ("md: raid1 add nowait support")
> Fixes: f51d46d0e7cb ("md: add support for REQ_NOWAIT")
> Suggested-by: Yu Kuai<[email protected]>
> Signed-off-by: Abd-Alrhman Masalkhi<[email protected]>
> ---
> drivers/md/md-bitmap.c | 9 +---
> drivers/md/md-bitmap.h | 2 +-
> drivers/md/md-llbitmap.c | 10 +----
> drivers/md/md.c | 15 ++-----
> drivers/md/raid1-10.c | 8 ++--
> drivers/md/raid1.c | 91 +++++++++-------------------------------
> drivers/md/raid10.c | 80 +++++++++--------------------------
> drivers/md/raid5.c | 13 ------
> 8 files changed, 51 insertions(+), 177 deletions(-)
Reviewed-by: Yu Kuai <[email protected]>
--
Thanks,
Kuai