From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Guido Trentalancia <guido@trentalancia.com>, linux-scsi@vger.kernel.org
Subject: Re: [PATCH RESEND v2] scsi: ignore Synchronize Cache command failures to keep using drives not supporting it
Date: Sun, 28 Feb 2021 08:37:03 -0800 [thread overview]
Message-ID: <443d92dd844e329bcd40a1e59b7cc3784ed3db94.camel@HansenPartnership.com> (raw)
In-Reply-To: <1614502908.6594.6.camel@trentalancia.com>
On Sun, 2021-02-28 at 10:01 +0100, Guido Trentalancia wrote:
> Many obsolete hard drives do not support the Synchronize Cache SCSI
> command. Such command is generally issued during fsync() calls which
> at the moment therefore fail with the ILLEGAL_REQUEST sense key.
It should be that all drives that don't support sync cache also don't
have write back caches, which means we don't try to do a cache sync on
them. The only time you we ever try to sync the cache is if the device
advertises a write back cache, in which case the sync cache command is
mandatory.
I'm sure some SATA manufacturers somewhere cut enough corners to
produce an illegally spec'd drive like this, but your proposed remedy
is unviable: you can't ignore a cache failure on flush barriers which
will cause data corruption. You have to disable barriers on the
filesystem to get correct operation and be very careful about power
down.
James
next prev parent reply other threads:[~2021-02-28 16:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-28 9:01 [PATCH RESEND v2] scsi: ignore Synchronize Cache command failures to keep using drives not supporting it Guido Trentalancia
2021-02-28 16:37 ` James Bottomley [this message]
2021-03-01 7:06 ` Guido Trentalancia
2021-03-01 7:38 ` Damien Le Moal
2021-03-01 11:33 ` Guido Trentalancia
2021-03-01 12:27 ` Damien Le Moal
2021-03-01 12:39 ` Guido Trentalancia
2021-03-01 12:51 ` Damien Le Moal
2021-03-01 12:57 ` Guido Trentalancia
2021-03-01 13:04 ` Damien Le Moal
2021-03-01 13:12 ` Guido Trentalancia
2021-03-01 12:42 ` Damien Le Moal
2021-03-01 12:52 ` Guido Trentalancia
2021-03-01 12:57 ` Damien Le Moal
2021-03-01 13:05 ` Guido Trentalancia
2021-03-01 12:07 ` Guido Trentalancia
-- strict thread matches above, loose matches on Subject: below --
2020-01-02 22:05 Guido Trentalancia
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