From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org
Subject: Re: [PATCH] block: Allow REQ_FUA|REQ_READ
Date: Tue, 11 Mar 2025 11:02:36 -0400 [thread overview]
Message-ID: <yq1bju7odgv.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20250311133517.3095878-1-kent.overstreet@linux.dev> (Kent Overstreet's message of "Tue, 11 Mar 2025 09:35:16 -0400")
Kent,
> REQ_FUA|REQ_READ means "do a read that bypasses the controller cache",
> the same as writes.
FUA does not bypass anything. On the contrary, A FUA READ causes data in
the volatile cache (if any) to be flushed to non-volatile storage
(either cache or media or both). So I'm afraid it has the exact opposite
effect of what you are looking for.
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2025-03-11 15:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-11 13:35 [PATCH] block: Allow REQ_FUA|REQ_READ Kent Overstreet
2025-03-11 14:53 ` Niklas Cassel
2025-03-11 15:09 ` Kent Overstreet
2025-03-11 15:13 ` Keith Busch
2025-03-11 15:02 ` Martin K. Petersen [this message]
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