From: "Martin K. Petersen" martin.petersen@oracle.com
hulk inclusion category: bugfix bugzilla: 46833 CVE: NA
-----------------------------------------------
Fix: https://gitee.com/src-openeuler/util-linux/issues/I28N07
Origin patch: https://patchwork.kernel.org/project/linux-scsi/patch/20190227041941. 1568-1-martin.petersen@oracle.com/
If partition table changed online, will record partition read-only flag.
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 jeremy@jcline.org Cc: Oleksii Kurochko olkuroch@cisco.com Cc: stable@vger.kernel.org # v4.16+ Reported-by: Oleksii Kurochko olkuroch@cisco.com 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 martin.petersen@oracle.com Signed-off-by: Ye Bin yebin10@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- block/blk-core.c | 2 +- block/genhd.c | 34 ++++++++++++++++++++++++---------- block/ioctl.c | 4 ++++ block/partition-generic.c | 7 +++++-- include/linux/genhd.h | 11 +++++++---- 5 files changed, 41 insertions(+), 17 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index ffbe326c70b9..41c40a6acdca 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2166,7 +2166,7 @@ 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 d8a9c901eaef..d9ec6bb4f880 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1543,26 +1543,40 @@ 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); }
@@ -1572,7 +1586,7 @@ 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 5a6157b3735a..899ffd50a7c6 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -455,6 +455,10 @@ 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 d86d794d28e1..63b82df5bbb4 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, @@ -352,7 +352,10 @@ 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); p->disk = disk;
if (info) { diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 666b23a88c6f..6a6da28ac0b9 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -116,7 +116,8 @@ 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; @@ -202,6 +203,7 @@ 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; @@ -440,12 +442,13 @@ 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);