[PATCH v4 2/2] buffer: record blockdev write errors in super_block that it backs

[Jeff Layton <jlayton@kernel.org>]

From: Jeff Layton <jlayton@redhat.com>

When syncing out a block device (a'la __sync_blockdev), any error
encountered will only be recorded in the bd_inode's mapping. When the
blockdev contains a filesystem however, we'd like to also record the
error in the super_block that's stored there.

Make mark_buffer_write_io_error also record the error in the
corresponding super_block when a writeback error occurs and the block
device contains a mounted superblock.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/buffer.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/buffer.c b/fs/buffer.c
index b8d28370cfd7..451f1be6e1a4 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1166,6 +1166,8 @@ void mark_buffer_write_io_error(struct buffer_head *bh)
 		mapping_set_error(bh->b_page->mapping, -EIO);
 	if (bh->b_assoc_map)
 		mapping_set_error(bh->b_assoc_map, -EIO);
+	if (bh->b_bdev->bd_super)
+		errseq_set(&bh->b_bdev->bd_super->s_wb_err, -EIO);
 }
 EXPORT_SYMBOL(mark_buffer_write_io_error);
 
-- 
2.24.1