fs: stop using bdev->bd_super in mark_buffer_write_io_error

bdev->bd_super is a somewhat awkward backpointer from a block device to
an owning file system with unclear rules.

For the buffer_head code we already have a good backpointer for the
inode that the buffer_head is associated with, even if it lives on the
block device mapping: b_assoc_map. It is used track dirty buffers
associated with an inode but living on the block device mapping like
directory buffers in ext4.

mark_buffer_write_io_error already uses it for the call to
mapping_set_error, and should be doing the same for the per-sb error
sequence.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230807112625.652089-2-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/buffer.c b/fs/buffer.c
index bd09132..f36ef03 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1225,19 +1225,14 @@ EXPORT_SYMBOL(mark_buffer_dirty);
 
 void mark_buffer_write_io_error(struct buffer_head *bh)
 {
-       struct super_block *sb;
-
        set_buffer_write_io_error(bh);
        /* FIXME: do we need to set this in both places? */
        if (bh->b_folio && bh->b_folio->mapping)
                mapping_set_error(bh->b_folio->mapping, -EIO);
-       if (bh->b_assoc_map)
+       if (bh->b_assoc_map) {
                mapping_set_error(bh->b_assoc_map, -EIO);
-       rcu_read_lock();
-       sb = READ_ONCE(bh->b_bdev->bd_super);
-       if (sb)
-               errseq_set(&sb->s_wb_err, -EIO);
-       rcu_read_unlock();
+               errseq_set(&bh->b_assoc_map->host->i_sb->s_wb_err, -EIO);
+       }
 }
 EXPORT_SYMBOL(mark_buffer_write_io_error);