[PATCH v6 16/20] block: convert to errseq_t based writeback error tracking

[Jeff Layton <jlayton@redhat.com>]

This is a very minimal conversion to errseq_t based error tracking
for raw block device access.

Only real change that is strictly required is that we must ensure that
filemap_report_wb_err is unconditionally called after fsync, which is
now done if FS_WB_ERRSEQ is set in fs_flags. That ensures that the
errseq_t in the file is advanced to the latest value in the mapping.

Note that there are internal callers that call sync_blockdev and the
like that are not affected by this. They'll continue to use the
AS_EIO/AS_ENOSPC flags for error reporting like they always have for
now.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 fs/block_dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 4d62fe771587..4bf865cc99de 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -801,6 +801,7 @@ static struct file_system_type bd_type = {
 	.name		= "bdev",
 	.mount		= bd_mount,
 	.kill_sb	= kill_anon_super,
+	.fs_flags	= FS_WB_ERRSEQ,
 };
 
 struct super_block *blockdev_superblock __read_mostly;
-- 
2.13.0