[PATCH 2/3] block: update the stable_writes flag in bdev_add

[Christoph Hellwig <hch@lst.de>]

Propagate the per-queue stable_write flags into each bdev inode in bdev_add.
This makes sure devices that require stable writes have it set for I/O
on the block device node as well.

Note that this doesn't cover the case of a flag changing on a live device
yet.  We should handle that as well, but I plan to cover it as part of a
more general rework of how changing runtime paramters on block devices
works.

Fixes: 1cb039f3dc16 ("bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag")
Reported-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bdev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/bdev.c b/block/bdev.c
index f3b13aa1b7d428..04dba25b0019eb 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -425,6 +425,8 @@ void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
 
 void bdev_add(struct block_device *bdev, dev_t dev)
 {
+	if (bdev_stable_writes(bdev))
+		mapping_set_stable_writes(bdev->bd_inode->i_mapping);
 	bdev->bd_dev = dev;
 	bdev->bd_inode->i_rdev = dev;
 	bdev->bd_inode->i_ino = dev;
-- 
2.39.2