From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout02.his.huawei.com (canpmsgout02.his.huawei.com [113.46.200.217]) (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 5C84D253B73; Thu, 28 May 2026 02:40:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.217 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779936046; cv=none; b=f8uEJEGggHXNe/TPZIVcQxEPJ+IAWwN+78Gcrx3fK6eqnxB8cLn+2FeiK0hg2VZgGylUFVeQCUXsXUirOb5npP4SoBOrgETYdDY2AVXr8K2h06WOvwPS8RPqyC+LFAVTHZkb//yhxh5l0RIANsOq5rc9C8lBmgyv+y06sjsHoW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779936046; c=relaxed/simple; bh=4ne/F3GhJd4ug+cucRL+Ux9T+hXykDXFIyYfjRJfAIc=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=RN3cKQoHIFMcZn9Z96//xN6gtR7q4g1Du6Fj5Y7ulxXnUE/NxrQFcdeTO+Rbop30ANCYtgi8T4J28fGCYnij2ca9pplYl2kedXlISno3zKF5bz/VdqU/ViwGdXFUlyGfT6kUx09dextBG5rGmox/w4l9rHXOtGZmcrTQ1/Kt4po= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=h-partners.com; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b=djrm+F5D; arc=none smtp.client-ip=113.46.200.217 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=h-partners.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=h-partners.com header.i=@h-partners.com header.b="djrm+F5D" dkim-signature: v=1; a=rsa-sha256; d=h-partners.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=Jq/ZSA0n/bM3e0hfO/ARy0dkxHT14vAwyRwagdoexeA=; b=djrm+F5DQGCkVTqx31dpvD0YALMrrCaudrkHDbapQLfN+vU471sEjQoH9EqJVyGCVUr5aaZBy e3a99/fq1R38a6F1UYpydL7QKi7XOB0y8TfRsKDT/HssbY+ZGYZLNBv6rDAYVrRlZME1xMwXzpc zJN8+Tbpkrnv0/r4TMwK21o= Received: from mail.maildlp.com (unknown [172.19.162.197]) by canpmsgout02.his.huawei.com (SkyGuard) with ESMTPS id 4gQrB66z8Dzcb19; Thu, 28 May 2026 10:32:46 +0800 (CST) Received: from kwepemj100018.china.huawei.com (unknown [7.202.194.12]) by mail.maildlp.com (Postfix) with ESMTPS id E7A3140569; Thu, 28 May 2026 10:40:34 +0800 (CST) Received: from [10.67.120.108] (10.67.120.108) by kwepemj100018.china.huawei.com (7.202.194.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 28 May 2026 10:40:34 +0800 Message-ID: Date: Thu, 28 May 2026 10:40:33 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.1 Subject: Re: [PATCH v3 2/2] scsi: libsas: Add linkrate and sas_addr change detection in rediscover Content-Language: en-CA To: John Garry , , , CC: , , , , , References: <20260515084531.866259-1-yangxingui@huawei.com> <20260515084531.866259-3-yangxingui@huawei.com> <5600f8fa-489a-9b81-9966-dc5d436c462e@huawei.com> <0a0f7284-8c11-4976-9377-d2fe9e0cf147@oracle.com> From: yangxingui In-Reply-To: <0a0f7284-8c11-4976-9377-d2fe9e0cf147@oracle.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepemh500008.china.huawei.com (7.202.181.139) To kwepemj100018.china.huawei.com (7.202.194.12) On 2026/5/27 17:42, John Garry wrote: > On 25/05/2026 03:25, yangxingui wrote: >>>> >>>> Hi, John >>>> As the commit log. The existing pattern (unregister + >>>> sas_discover_new) handles the "replace" case where the SAS address >>>> changes completely, implying a different device. >>>> For the flutter case where we detect linkrate/sas_addr changes, >>> >>> Can you please clarify this: you say that the existing pattern >>> handles "replace" case where the SAS address changes completely, and >>> then flutter case covers sas_addr changes. >>> >>> What is the difference in the SAS address changes between the two cases? >>> >> Hi, John >> >> The difference is in when the SAS address change is detected: >> Replace case: >> - Detected immediately by the initial SMP DISCOVER response >> - New SAS address differs from stored phy->attached_sas_addr >> >> Flutter case: >> - Initial SMP DISCOVER shows SAS address matching stored phy- >>  >attached_sas_addr >> - Linkrate may change >> - After sas_ex_phy_discover() refreshes phy info, child device address >> and linkrate may mismatched with refreshed phy info >> >> Additional issue with Replace flow: >> The existing replace code path also suffers from the same >> sysfs_warn_dup issue I mentioned earlier. >> sas_unregister_devs_sas_addr() only marks the device as gone and adds >> it to destroy_list. The actual sysfs cleanup happens later in >> sas_destruct_devices(). Calling sas_discover_new() immediately after >> unregister causes sysfs duplicate directory errors. >> > > So can you actually recreate this issue? Or is it just theoretical? Yes, it can recreate, such as quickly replacing a disk or swapping two disk. However, during normal use, we recommend that customers wait for one minute before inserting a new disk when replacing a disk to avoid this issue. The following are example of similar exception logs: log1： [ 7957.283194][T67794] sas: ex 500e004aaaaaaa1f phy19 replace 5001882016000000 [ 7957.290960][T67794] sysfs: cannot create duplicate filename '/devices/pci0000:74/0000:74:02.0/host1/port-1:2/expander-1:2/port-1:2:19' [ 7957.317973][T67794] Hardware name: Huawei Technologies Co., Ltd. EVBCS/EVBCS, BIOS CS B055 2P TA 02/19/2020 [ 7957.328900][T67794] Workqueue: 0000:74:02.0_disco_q sas_revalidate_domain [libsas] [ 7957.337636][T67794] Call trace: [ 7957.341419][T67794] dump_backtrace+0x0/0x200 [ 7957.346317][T67794] show_stack+0x20/0x30 [ 7957.350887][T67794] dump_stack+0xf0/0x138 [ 7957.355511][T67794] sysfs_warn_dup+0x6c/0x90 [ 7957.360410][T67794] sysfs_create_dir_ns+0xf8/0x11c [ 7957.365795][T67794] create_dir+0x30/0x18c [ 7957.370416][T67794] kobject_add_internal+0x5c/0x190 [ 7957.375877][T67794] kobject_add+0x98/0x110 [ 7957.380566][T67794] device_add+0x100/0x4a0 [ 7957.385255][T67794] sas_port_add+0x30/0x74 [scsi_transport_sas] [ 7957.391722][T67794] sas_ex_discover_end_dev+0x328/0x630 [libsas] [ 7957.398328][T67794] sas_ex_discover_dev+0x230/0x320 [libsas] [ 7957.404599][T67794] sas_ex_discover_devices+0x60/0x100 [libsas] [ 7957.411116][T67794] sas_discover_new+0xa4/0x150 [libsas] [ 7957.416986][T67794] sas_rediscover_dev+0x198/0x260 [libsas] [ 7957.423125][T67794] sas_rediscover+0xb8/0x100 [libsas] [ 7957.428854][T67794] sas_ex_revalidate_domain+0x5c/0xe0 [libsas] [ 7957.435320][T67794] sas_revalidate_domain+0x1ac/0x1b4 [libsas] [ 7957.441714][T67794] process_one_work+0x1d8/0x4cc [ 7957.446884][T67794] worker_thread+0x158/0x410 [ 7957.451769][T67794] kthread+0x108/0x13c [ 7957.456089][T67794] ret_from_fork+0x10/0x18 [ 7957.460800][T67794] kobject_add_internal failed for port-1:2:19 with -EEXIST, don't try to register things with the same name in the same directory. [ 7957.474864][T67794] sas: ex 500e004aaaaaaa1f phy19 failed to discover log2： [ 8608.766031][T66335] sas: ex 500e004aaaaaaa1f phy17 change count has changed [ 8608.774390][T66335] sysfs: cannot create duplicate filename '/devices/pci0000:74/0000:74:02.0/host1/port-1:2/expander-1:3/port-1:3:17' [ 8608.800667][T66335] Hardware name: Huawei Technologies Co., Ltd. EVBCS/EVBCS, BIOS CS B055 2P TA 02/19/2020 [ 8608.811270][T66335] Workqueue: 0000:74:02.0_disco_q sas_revalidate_domain [libsas] [ 8608.819685][T66335] Call trace: [ 8608.823235][T66335] dump_backtrace+0x0/0x200 [ 8608.827990][T66335] show_stack+0x20/0x30 [ 8608.832387][T66335] dump_stack+0xf0/0x138 [ 8608.836858][T66335] sysfs_warn_dup+0x6c/0x90 [ 8608.841580][T66335] sysfs_create_dir_ns+0xf8/0x11c [ 8608.846814][T66335] create_dir+0x30/0x18c [ 8608.851257][T66335] kobject_add_internal+0x5c/0x190 [ 8608.856566][T66335] kobject_add+0x98/0x110 [ 8608.861083][T66335] device_add+0x100/0x4a0 [ 8608.865588][T66335] sas_port_add+0x30/0x74 [scsi_transport_sas] [ 8608.871919][T66335] sas_ex_discover_end_dev+0x328/0x630 [libsas] [ 8608.878345][T66335] sas_ex_discover_dev+0x230/0x320 [libsas] [ 8608.884430][T66335] sas_ex_discover_devices+0x60/0x100 [libsas] [ 8608.890768][T66335] sas_discover_new+0xa4/0x150 [libsas] [ 8608.896506][T66335] sas_rediscover+0xd8/0x100 [libsas] [ 8608.902075][T66335] sas_ex_revalidate_domain+0x5c/0xe0 [libsas] [ 8608.908438][T66335] sas_revalidate_domain+0x1ac/0x1b4 [libsas] [ 8608.914708][T66335] process_one_work+0x1d8/0x4cc [ 8608.919757][T66335] worker_thread+0x158/0x410 [ 8608.924533][T66335] kthread+0x108/0x13c [ 8608.928778][T66335] ret_from_fork+0x10/0x18 [ 8608.933377][T66335] kobject_add_internal failed for port-1:3:17 with -EEXIST, don't try to register things with the same name in the same directory. [ 8608.947364][T66335] sas: ex 500e004aaaaaaa1f phy17 failed to discover > About this following code: > > +        if (need_rediscover) { > +            set_bit(SAS_DEV_GONE, &child_dev->state); > +            phy->phy_change_count = -1; > +            ex->ex_change_count = -1; > +            sas_unregister_devs_sas_addr(dev, phy_id, true); > +            sas_discover_event(dev->port, DISCE_REVALIDATE_DOMAIN); > +        } else { > > > Can we factor it out with other code? AFAICR, this can pattern can be > seen elsewhere. Yes, in the updated v4 version, I refined it into a function. In the v4 test log, the disk is gone and then connected again. test case: phy=phy-10:0:0 echo 1.5 Gbit > /sys/class/sas_phy/$phy/maximum_linkrate The details are as follows: [ 541.880156] sas: broadcast received: 0 [ 541.880712] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.882509] sas: ex 500e004aaaaaaa1f phy00 change count has changed [ 541.883680] sas: ex 500e004aaaaaaa1f phy00 originated BROADCAST(CHANGE) [ 541.883703] sas: ex 500e004aaaaaaa1f rediscovering phy00 [ 541.884838] sas: ex 500e004aaaaaaa1f phy00:U:8 attached: 500e004aaaaaaa00 (stp pending) [ 541.884844] sas: ex 500e004aaaaaaa1f phy00 broadcast flutter, needs recovery [ 541.898893] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.899444] sas: broadcast received: 0 [ 541.899506] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.899659] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.900213] sas: broadcast received: 0 [ 541.900282] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.900367] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.900992] sas: broadcast received: 0 [ 541.901041] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.901132] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.901160] sas: broadcast received: 0 [ 541.901195] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.901278] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.901887] sas: broadcast received: 0 [ 541.901948] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.902035] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.902673] sas: broadcast received: 0 [ 541.902741] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.902836] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.903467] sas: broadcast received: 0 [ 541.903536] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.903625] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 541.919967] sas: broadcast received: 0 [ 541.920036] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 541.920385] sas: ex 500e004aaaaaaa1f phy00 change count has changed [ 541.920494] sas: ex 500e004aaaaaaa1f phy00 originated BROADCAST(CHANGE) [ 541.920504] sas: ex 500e004aaaaaaa1f rediscovering phy00 [ 541.920687] sas: ex 500e004aaaaaaa1f phy00:U:8 attached: 500e004aaaaaaa00 (stp) [ 541.920697] sas: ex 500e004aaaaaaa1f phy00 linkrate changed from 9 to 8 [ 541.920710] sas: ex 500e004aaaaaaa1f phy00 replace 500e004aaaaaaa00 [ 541.922648] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 542.007031] sd 10:0:0:0: [sdd] Stopping disk [ 542.007122] sd 10:0:0:0: [sdd] Start/Stop Unit failed: Result: hostbyte=0x04 driverbyte=DRIVER_OK [ 542.027347] hisi_sas_v3_hw 0000:70:04.0: dev[2:5] is gone [ 542.039000] sas: REVALIDATING DOMAIN on port 0, pid:8995 [ 542.039358] sas: ex 500e004aaaaaaa1f phy00 change count has changed [ 542.039436] sas: broadcast received: 0 [ 542.039470] sas: ex 500e004aaaaaaa1f phy00 originated BROADCAST(CHANGE) [ 542.039482] sas: ex 500e004aaaaaaa1f phy00 new device attached [ 542.039569] sas: ex 500e004aaaaaaa1f phy00:U:8 attached: 500e004aaaaaaa00 (stp) [ 542.040152] hisi_sas_v3_hw 0000:70:04.0: dev[15:5] found [ 542.042112] sas: done REVALIDATING DOMAIN on port 0, pid:8995, res 0x0 [ 542.153137] sas: Enter sas_scsi_recover_host busy: 0 failed: 0 [ 542.153900] sas: ata10: end_device-10:0:1: dev error handler [ 542.153972] sas: ata11: end_device-10:0:2: dev error handler [ 542.153994] sas: ata12: end_device-10:0:5: dev error handler [ 542.154010] sas: ata13: end_device-10:0:6: dev error handler [ 542.154021] sas: ata14: end_device-10:0:9: dev error handler [ 542.154032] sas: ata15: end_device-10:0:10: dev error handler [ 542.154044] sas: ata9: end_device-10:0:0: dev error handler [ 542.519243] ata9.00: ATA-10: ST4000NM0035-1V4107, TN03, max UDMA/133 [ 542.522538] ata9.00: 7814037168 sectors, multi 0: LBA48 NCQ (depth 32) [ 542.522561] ata9.00: Features: DIPM NCQ-sndrcv [ 542.527315] ata9.00: configured for UDMA/133 [ 542.527976] sas: --- Exit sas_scsi_recover_host: busy: 0 failed: 0 tries: 1 [ 542.570193] scsi 10:0:13:0: Direct-Access ATA ST4000NM0035-1V4 TN03 PQ: 0 ANSI: 5 [ 542.571771] scsi 10:0:13:0: Attached scsi generic sg3 type 0 Thanks, Xingui