[PATCH v7 16/22] block: convert to errseq_t based writeback error tracking

[Jeff Layton]

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
unconditionally call filemap_report_wb_err in blkdev_fsync.
That ensures that the file's errseq_t is always 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 <jlay...@redhat.com>
---
 fs/block_dev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index dc839f8f0ba5..9e8e13b097ef 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -625,11 +625,11 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t 
end, int datasync)
 {
        struct inode *bd_inode = bdev_file_inode(filp);
        struct block_device *bdev = I_BDEV(bd_inode);
-       int error;
+       int error, wberr;
        
        error = filemap_write_and_wait_range(filp->f_mapping, start, end);
        if (error)
-               return error;
+               goto out;
 
        /*
         * There is no need to serialise calls to blkdev_issue_flush with
@@ -640,6 +640,10 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t 
end, int datasync)
        if (error == -EOPNOTSUPP)
                error = 0;
 
+out:
+       wberr = filemap_report_wb_err(filp);
+       if (!error)
+               error = wberr;
        return error;
 }
 EXPORT_SYMBOL(blkdev_fsync);
-- 
2.13.0