From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77697C43381 for ; Thu, 7 Mar 2019 00:39:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30E0A206DD for ; Thu, 7 Mar 2019 00:39:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WkTbl8gj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726120AbfCGAjL (ORCPT ); Wed, 6 Mar 2019 19:39:11 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:38032 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726094AbfCGAjL (ORCPT ); Wed, 6 Mar 2019 19:39:11 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x270cvQr147657; Thu, 7 Mar 2019 00:39:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : subject : from : references : date : in-reply-to : message-id : mime-version : content-type; s=corp-2018-07-02; bh=csLS+Eg2Py2ppCPlF+MCBjz9E0zV0s16dVIRi22hKcY=; b=WkTbl8gjFgWZjWUH2Q31eGoTqHQRtUbcrMGE7ef/Eccx8afPfZ3ntW28rHD/UgGnShOu kbfFhtMMemV+cX6pcYEXDLwAsry+XP6Ro4fClMa0O22SH+KTjT6J1a29Prk3y8PaRjxq RmvOUcC732L25TOuXWo156ql0ei3KAMsfBjnX8vP97WbyqjC3sIHuEChGSWGjbwni8VQ OyALwAFcb0ef5GR4+paJoeNMX5+ZXyF6g3e/EIpVhuXpiy7NMYBM91PIc36AqD6maR+I ZM16lQ5MT6X0JixnA0mt4Y9p2BugLlMmhqbsMKSK5oU1jK6sdmvYLiYEKnjG+3Qwoqmm Xw== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2qyjfrq168-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 07 Mar 2019 00:39:09 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x270d3rw026693 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 7 Mar 2019 00:39:03 GMT Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x270d2fW026920; Thu, 7 Mar 2019 00:39:03 GMT Received: from ca-mkp.ca.oracle.com (/10.159.214.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 06 Mar 2019 16:39:02 -0800 To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: [PATCH v3] scsi: sd: block: Fix regressions in read-only block device handling From: "Martin K. Petersen" Organization: Oracle Corporation References: <20190222142957.GA17324@infradead.org> <20190227041941.1568-1-martin.petersen@oracle.com> Date: Wed, 06 Mar 2019 19:39:00 -0500 In-Reply-To: <20190227041941.1568-1-martin.petersen@oracle.com> (Martin K. Petersen's message of "Tue, 26 Feb 2019 23:19:41 -0500") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9187 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903070002 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Somebody please review, need this regression fixed in stable! > Some devices come online in write protected state and switch to > read-write once they are ready to process I/O requests. These devices > broke with commit 20bd1d026aac ("scsi: sd: Keep disk read-only when > re-reading partition") because we had no way to distinguish between a > user decision to set a block_device read-only and the actual hardware > device being write-protected. > > Because partitions are dropped and recreated on revalidate we are > unable to persist any user-provided policy in hd_struct. Introduce a > bitmap in struct gendisk to track the user configuration. This bitmap > is updated when BLKROSET is called on a given disk or partition. > > A helper function, get_user_ro(), is provided to determine whether the > ioctl has forced read-only state for a given block device. This helper > is used by set_disk_ro() and add_partition() to ensure that both > existing and newly created partitions will get the correct state. > > - If BLKROSET sets a whole disk device read-only, all partitions will > now end up in a read-only state. > > - If BLKROSET sets a given partition read-only, that partition will > remain read-only post revalidate. > > - Otherwise both the whole disk device and any partitions will > reflect the write protect state of the underlying device. > > Since nobody knows what "policy" means, rename the field to > "read_only" for clarity. > > Cc: Jeremy Cline > Cc: Oleksii Kurochko > Cc: stable@vger.kernel.org # v4.16+ > Reported-by: Oleksii Kurochko > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201221 > Fixes: 20bd1d026aac ("scsi: sd: Keep disk read-only when re-reading partition") > Signed-off-by: Martin K. Petersen > > --- > > v3: > - Drop ?: since gcc complains about mixing int and bool (zeroday) > - Drop EXPORT_SYMBOL (hch) > - s/policy/read_only/ and make it a boolean > > v2: > - Track user read-only state in a bitmap > > - Work around the regression that caused us to drop user > preferences on revalidate > --- > block/blk-core.c | 2 +- > block/genhd.c | 34 ++++++++++++++++++++++++---------- > block/ioctl.c | 4 ++++ > block/partition-generic.c | 7 +++++-- > drivers/scsi/sd.c | 4 +--- > include/linux/genhd.h | 11 +++++++---- > 6 files changed, 42 insertions(+), 20 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index c78042975737..c28d7ee3a05e 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -790,7 +790,7 @@ static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) > { > const int op = bio_op(bio); > > - if (part->policy && op_is_write(op)) { > + if (part->read_only && op_is_write(op)) { > char b[BDEVNAME_SIZE]; > > if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) > diff --git a/block/genhd.c b/block/genhd.c > index 1dd8fd6613b8..c07037c0b03f 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -1537,26 +1537,40 @@ static void set_disk_ro_uevent(struct gendisk *gd, int ro) > kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); > } > > -void set_device_ro(struct block_device *bdev, int flag) > +void set_device_ro(struct block_device *bdev, bool state) > { > - bdev->bd_part->policy = flag; > + bdev->bd_part->read_only = state; > } > > EXPORT_SYMBOL(set_device_ro); > > -void set_disk_ro(struct gendisk *disk, int flag) > +bool get_user_ro(struct gendisk *disk, unsigned int partno) > +{ > + /* Is the user read-only bit set for the whole disk device? */ > + if (test_bit(0, disk->user_ro_bitmap)) > + return true; > + > + /* Is the user read-only bit set for this particular partition? */ > + if (test_bit(partno, disk->user_ro_bitmap)) > + return true; > + > + return false; > +} > + > +void set_disk_ro(struct gendisk *disk, bool state) > { > struct disk_part_iter piter; > struct hd_struct *part; > > - if (disk->part0.policy != flag) { > - set_disk_ro_uevent(disk, flag); > - disk->part0.policy = flag; > - } > + if (disk->part0.read_only != state) > + set_disk_ro_uevent(disk, state); > > - disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); > + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY_PART0); > while ((part = disk_part_iter_next(&piter))) > - part->policy = flag; > + if (get_user_ro(disk, part->partno)) > + part->read_only = true; > + else > + part->read_only = state; > disk_part_iter_exit(&piter); > } > > @@ -1566,7 +1580,7 @@ int bdev_read_only(struct block_device *bdev) > { > if (!bdev) > return 0; > - return bdev->bd_part->policy; > + return bdev->bd_part->read_only; > } > > EXPORT_SYMBOL(bdev_read_only); > diff --git a/block/ioctl.c b/block/ioctl.c > index 4825c78a6baa..41206df89485 100644 > --- a/block/ioctl.c > +++ b/block/ioctl.c > @@ -451,6 +451,10 @@ static int blkdev_roset(struct block_device *bdev, fmode_t mode, > return ret; > if (get_user(n, (int __user *)arg)) > return -EFAULT; > + if (n) > + set_bit(bdev->bd_partno, bdev->bd_disk->user_ro_bitmap); > + else > + clear_bit(bdev->bd_partno, bdev->bd_disk->user_ro_bitmap); > set_device_ro(bdev, n); > return 0; > } > diff --git a/block/partition-generic.c b/block/partition-generic.c > index 8e596a8dff32..2bade849cc5c 100644 > --- a/block/partition-generic.c > +++ b/block/partition-generic.c > @@ -98,7 +98,7 @@ static ssize_t part_ro_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > struct hd_struct *p = dev_to_part(dev); > - return sprintf(buf, "%d\n", p->policy ? 1 : 0); > + return sprintf(buf, "%u\n", p->read_only ? 1 : 0); > } > > static ssize_t part_alignment_offset_show(struct device *dev, > @@ -338,7 +338,10 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno, > queue_limit_discard_alignment(&disk->queue->limits, start); > p->nr_sects = len; > p->partno = partno; > - p->policy = get_disk_ro(disk); > + if (get_user_ro(disk, partno)) > + p->read_only = true; > + else > + p->read_only = get_disk_ro(disk); > > if (info) { > struct partition_meta_info *pinfo = alloc_part_info(disk); > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 67cc439b86e4..5dfe37b08d3b 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -2591,10 +2591,8 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer) > int res; > struct scsi_device *sdp = sdkp->device; > struct scsi_mode_data data; > - int disk_ro = get_disk_ro(sdkp->disk); > int old_wp = sdkp->write_prot; > > - set_disk_ro(sdkp->disk, 0); > if (sdp->skip_ms_page_3f) { > sd_first_printk(KERN_NOTICE, sdkp, "Assuming Write Enabled\n"); > return; > @@ -2632,7 +2630,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer) > "Test WP failed, assume Write Enabled\n"); > } else { > sdkp->write_prot = ((data.device_specific & 0x80) != 0); > - set_disk_ro(sdkp->disk, sdkp->write_prot || disk_ro); > + set_disk_ro(sdkp->disk, sdkp->write_prot); > if (sdkp->first_scan || old_wp != sdkp->write_prot) { > sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n", > sdkp->write_prot ? "on" : "off"); > diff --git a/include/linux/genhd.h b/include/linux/genhd.h > index 06c0fd594097..1abde0e88ccb 100644 > --- a/include/linux/genhd.h > +++ b/include/linux/genhd.h > @@ -118,7 +118,8 @@ struct hd_struct { > unsigned int discard_alignment; > struct device __dev; > struct kobject *holder_dir; > - int policy, partno; > + bool read_only; > + int partno; > struct partition_meta_info *info; > #ifdef CONFIG_FAIL_MAKE_REQUEST > int make_it_fail; > @@ -194,6 +195,7 @@ struct gendisk { > */ > struct disk_part_tbl __rcu *part_tbl; > struct hd_struct part0; > + DECLARE_BITMAP(user_ro_bitmap, DISK_MAX_PARTS); > > const struct block_device_operations *fops; > struct request_queue *queue; > @@ -431,12 +433,13 @@ extern void del_gendisk(struct gendisk *gp); > extern struct gendisk *get_gendisk(dev_t dev, int *partno); > extern struct block_device *bdget_disk(struct gendisk *disk, int partno); > > -extern void set_device_ro(struct block_device *bdev, int flag); > -extern void set_disk_ro(struct gendisk *disk, int flag); > +extern void set_device_ro(struct block_device *bdev, bool state); > +extern void set_disk_ro(struct gendisk *disk, bool state); > +extern bool get_user_ro(struct gendisk *disk, unsigned int partno); > > static inline int get_disk_ro(struct gendisk *disk) > { > - return disk->part0.policy; > + return disk->part0.read_only; > } > > extern void disk_block_events(struct gendisk *disk); -- Martin K. Petersen Oracle Linux Engineering