Anybody could help review this bug? thanks,
Junxiao. On 8/5/19 1:01 PM, Junxiao Bi wrote:
When md raid1 was used with imsm metadata, during the boot stage, the raid device will first be set to readonly, then mdmon will set it read-write later. When there were some partitions in this device, the following race would make some partition left ro and fail to mount. CPU 1: CPU 2: add_partition() set_disk_ro() //set disk RW //disk was RO, so partition set to RO p->policy = get_disk_ro(disk); if (disk->part0.policy != flag) { set_disk_ro_uevent(disk, flag); // disk set to RW disk->part0.policy = flag; } // set all exit partition to RW while ((part = disk_part_iter_next(&piter))) part->policy = flag; // this part was not yet added, so it was still RO rcu_assign_pointer(ptbl->part[partno], p); Move RO status setting of partitions after they were added into partition table and introduce a mutex to sync RO status between disk and partitions. Signed-off-by: Junxiao Bi <junxiao...@oracle.com> --- block/genhd.c | 3 +++ block/partition-generic.c | 5 ++++- include/linux/genhd.h | 1 + 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/block/genhd.c b/block/genhd.c index 54f1f0d381f4..f3cce1d354cf 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1479,6 +1479,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id) } ptbl = rcu_dereference_protected(disk->part_tbl, 1); rcu_assign_pointer(ptbl->part[0], &disk->part0); + mutex_init(&disk->part_lock);/** set_capacity() and get_capacity() currently don't use @@ -1570,6 +1571,7 @@ void set_disk_ro(struct gendisk *disk, int flag) struct disk_part_iter piter; struct hd_struct *part;+ mutex_lock(&disk->part_lock);if (disk->part0.policy != flag) { set_disk_ro_uevent(disk, flag); disk->part0.policy = flag; @@ -1579,6 +1581,7 @@ void set_disk_ro(struct gendisk *disk, int flag) while ((part = disk_part_iter_next(&piter))) part->policy = flag; disk_part_iter_exit(&piter); + mutex_unlock(&disk->part_lock); }EXPORT_SYMBOL(set_disk_ro);diff --git a/block/partition-generic.c b/block/partition-generic.c index aee643ce13d1..63cb6fb996ff 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -345,7 +345,6 @@ 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 (info) {struct partition_meta_info *pinfo = alloc_part_info(disk); @@ -401,6 +400,10 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno, /* everything is up and running, commence */ rcu_assign_pointer(ptbl->part[partno], p);+ mutex_lock(&disk->part_lock);+ p->policy = get_disk_ro(disk); + mutex_unlock(&disk->part_lock); + /* suppress uevent if the disk suppresses it */ if (!dev_get_uevent_suppress(ddev)) kobject_uevent(&pdev->kobj, KOBJ_ADD); diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 8b5330dd5ac0..df6ddca8a92c 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -201,6 +201,7 @@ struct gendisk { */ struct disk_part_tbl __rcu *part_tbl; struct hd_struct part0; + struct mutex part_lock;const struct block_device_operations *fops;struct request_queue *queue;
