[PATCH v3 04/11] block_dev: Introduce bd_corrupted_range() for block device

Shiyang Ruan
2021-02-08T11:07:31Z

As is show in the call tree:
...
pgmap->ops->memory_failure()
gendisk->fops->corrupted_range()
sb->s_ops->currupted_range()
...
currupted_range() is called from disk(pmem) to superblock(filesystem).
Thus, we need to introduce a helper function to obtain the superblock
from a given disk.

Normally, a filesystem can be created by mkfs directly on a block device
or a parted disk. We can obtain the superblock by calling get_super().

But get_super() is not suitable for mapped device, such as LVM. To
obtain MD's superblock, we can iterate bd_holder_disks of a block device
to find out the MD that contains it. By this way, MD is able to call
corrupted_range() from its target block device.

Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
---
fs/block_dev.c | 47 ++++++++++++++++++++++++++++++++++++++++++-
include/linux/genhd.h | 2 ++
2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3b8963e228a1..755b0d351479 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1079,6 +1079,28 @@ struct bd_holder_disk {
int refcnt;
};

+static int bd_disk_holder_corrupted_range(struct block_device *bdev, loff_t off,
+ size_t len, void *data)
+{
+ struct bd_holder_disk *holder;
+ struct gendisk *disk;
+ int rc = 0;
+
+ if (list_empty(&(bdev->bd_holder_disks)))
+ return -ENODEV;
+
+ list_for_each_entry(holder, &bdev->bd_holder_disks, list) {
+ disk = holder->disk;
+ if (disk->fops->corrupted_range) {
+ rc = disk->fops->corrupted_range(disk, bdev, off,
+ len, data);
+ if (rc != -ENODEV)
+ break;
+ }
+ }
+ return rc;
+}
+
static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
struct gendisk *disk)
{
@@ -1212,7 +1234,30 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
mutex_unlock(&bdev->bd_mutex);
}
EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
-#endif
+#else
+static inline int bd_disk_holder_corrupted_range(struct block_device *bdev,
+ loff_t off, size_t len, void *data)
+{
+ return -EOPNOTSUPP;
+}
+#endif /* CONFIG_SYSFS */
+
+int bd_corrupted_range(struct block_device *bdev, loff_t disk_off,
+ loff_t bdev_off, size_t len, void *data)
+{
+ struct super_block *sb = get_super(bdev);
+ int rc = -EOPNOTSUPP;
+
+ if (!sb) {
+ rc = bd_disk_holder_corrupted_range(bdev, disk_off, len, data);
+ return rc;
+ } else if (sb->s_op->corrupted_range)
+ rc = sb->s_op->corrupted_range(sb, bdev, bdev_off, len, data);
+ drop_super(sb);
+
+ return rc;
+}
+EXPORT_SYMBOL(bd_corrupted_range);

static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 809aaa32d53c..751cbd559bba 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -314,6 +314,8 @@ void unregister_blkdev(unsigned int major, const char *name);
bool bdev_check_media_change(struct block_device *bdev);
int __invalidate_device(struct block_device *bdev, bool kill_dirty);
void set_capacity(struct gendisk *disk, sector_t size);
+int bd_corrupted_range(struct block_device *bdev, loff_t disk_off,
+ loff_t bdev_off, size_t len, void *data);

/* for drivers/char/raw.c: */
int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
--
2.30.0