From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 429D31A2C17 for ; Wed, 8 May 2024 01:30:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715131838; cv=none; b=No4YcXHFSp5G+W7mwHrm+IXSAsz+E/VQhUMmSK6AZaSZyqLQLDSFMeKKNm+PlVIhQq0vVfh0g+Bbg9UB8BjjN9+wDWT/2hIlHvf1JJdu2muh+zrf5UtgZFHJKhnOMXh+mMWFzXNnch0S6HZX1oJu7dnkWIjVfsvciAVHtpOke+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715131838; c=relaxed/simple; bh=jdJDZKJdsgvk3YuSXDBTZS+7mincWLYme4q4TIgdzLU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bHb5tJD6/ncBBpOuOD6FMvdLxGUXVYjZeewqbsifaD7UE+OqpULPxQInQMhnL6nfSPObKB1qdipwkz+F5xDxxfsdV4nDpj63uppK55y6Y5bkoocWwfbMltUGzYM/Kv7U07/YZX85hwnARrMsh/glf0SYelk+ghQA059b69/tjp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=V0ArTkxc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="V0ArTkxc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5FD2C2BBFC; Wed, 8 May 2024 01:30:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715131837; bh=jdJDZKJdsgvk3YuSXDBTZS+7mincWLYme4q4TIgdzLU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=V0ArTkxcl1LJd3TATg9qix3xikRZJZ9161sHP70jOZY6zeTpusGYb9O10t/yn/fp8 T6KESDWl6XfuCGuCGof80jhbc2Ab5a+yBlBGDlHStdbs33UibipQ20DwKMyRx1im1F DKJFKP45wP06gxKZCRnfrWXka7F2sEPWFD2K+/43y/9NL6WemyyaE2bYBq/GZP5eXc dBhnMim5zv+zJovVxITp+EZUAcnAxs9HtFycTyTE9hujST7w9eibOr/iXJ2oUUFzN+ lWU2W4kRJ3xsalDmae+sxNSEnKvfdUsf8jcC5yUkF1qRBsBYgx03JKmCXz10a0VqdY Sb8/oCW4DnTDQ== Message-ID: <0b32bd8d-e407-465f-b021-c862419e6160@kernel.org> Date: Wed, 8 May 2024 10:30:34 +0900 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] I/O errors for ALUA state transitions To: Martin Wilck , "Martin K. Petersen" , Christoph Hellwig , Hannes Reinecke , James Bottomley , Ewan Milne , Mike Christie Cc: Bart Van Assche , linux-scsi@vger.kernel.org, Martin Wilck References: <20240507092837.21463-1-mwilck@suse.com> Content-Language: en-US From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <20240507092837.21463-1-mwilck@suse.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/7/24 6:28 PM, Martin Wilck wrote: > From: Rajashekhar M A > > When a host is configured with a few LUNs and IO is running, > injecting FC faults repeatedly leads to path recovery problems. > The LUNs have 4 paths each and 3 of them come back active after > say an FC fault which makes two of the paths go down, instead of > all 4. This happens after several iterations of continuous FC faults. > > Reason here is that we're returning an I/O error whenever we're > encountering sense code 06/04/0a (LOGICAL UNIT NOT ACCESSIBLE, > ASYMMETRIC ACCESS STATE TRANSITION) instead of retrying. > > mwilck: Moved this code to alua_check_sense() as suggested by > Mike Christie [1]. Evan Milne had raised the question whether pg->state > should be set to transitioning in the UA case [2]. I believe that doing > this is correct. SCSI_ACCESS_STATE_TRANSITIONING by itself doesn't cause > I/O errors. Our handler schedules an RTPG, which will only result in > an I/O error condition if the transitioning timeout expires. > > [1] https://lore.kernel.org/all/0bc96e82-fdda-4187-148d-5b34f81d4942@oracle.com/ > [2] https://lore.kernel.org/all/CAGtn9r=kicnTDE2o7Gt5Y=yoidHYD7tG8XdMHEBJTBraVEoOCw@mail.gmail.com/ > > Signed-off-by: Hannes Reinecke > Signed-off-by: Martin Wilck > > --- > Changes v2->v3: > - drop return value of alua_handle_state_transition() (Christoph Hellwig) > - handle UNIT ATTENTION in alua_tur(), too (Mike Christie) > - restore comment in alua_check_sense() (Damien Le Moal) > > --- > drivers/scsi/device_handler/scsi_dh_alua.c | 33 +++++++++++++++------- > 1 file changed, 23 insertions(+), 10 deletions(-) > > diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c > index a226dc1b65d7..c6408678e7c4 100644 > --- a/drivers/scsi/device_handler/scsi_dh_alua.c > +++ b/drivers/scsi/device_handler/scsi_dh_alua.c > @@ -414,28 +414,40 @@ static char print_alua_state(unsigned char state) > } > } > > -static enum scsi_disposition alua_check_sense(struct scsi_device *sdev, > - struct scsi_sense_hdr *sense_hdr) > +static void alua_handle_state_transition(struct scsi_device *sdev) > { > struct alua_dh_data *h = sdev->handler_data; > struct alua_port_group *pg; > > + rcu_read_lock(); > + pg = rcu_dereference(h->pg); > + if (pg) > + pg->state = SCSI_ACCESS_STATE_TRANSITIONING; > + rcu_read_unlock(); > + alua_check(sdev, false); > +} > + > +static enum scsi_disposition alua_check_sense(struct scsi_device *sdev, > + struct scsi_sense_hdr *sense_hdr) > +{ > switch (sense_hdr->sense_key) { > case NOT_READY: > - if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { > + if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a){ You removed the space before the curly bracket... With that fixed, feel free to add: Reviewed-by: Damien Le Moal > /* > * LUN Not Accessible - ALUA state transition > */ > - rcu_read_lock(); > - pg = rcu_dereference(h->pg); > - if (pg) > - pg->state = SCSI_ACCESS_STATE_TRANSITIONING; > - rcu_read_unlock(); > - alua_check(sdev, false); > + alua_handle_state_transition(sdev); > return NEEDS_RETRY; > } > break; > case UNIT_ATTENTION: > + if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { > + /* > + * LUN Not Accessible - ALUA state transition > + */ > + alua_handle_state_transition(sdev); > + return NEEDS_RETRY; > + } > if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) { > /* > * Power On, Reset, or Bus Device Reset. > @@ -502,7 +514,8 @@ static int alua_tur(struct scsi_device *sdev) > > retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ, > ALUA_FAILOVER_RETRIES, &sense_hdr); > - if (sense_hdr.sense_key == NOT_READY && > + if ((sense_hdr.sense_key == NOT_READY || > + sense_hdr.sense_key == UNIT_ATTENTION) && > sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) > return SCSI_DH_RETRY; > else if (retval) -- Damien Le Moal Western Digital Research