On Mon, 2018-06-04 at 14:03 -0400, Jeff Layton wrote: > From: Jeff Layton <jlayton@xxxxxxxxxx> > > 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@xxxxxxxxxx> > --- > fs/buffer.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/buffer.c b/fs/buffer.c > index 249b83fafe48..dae2a857d5bc 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -1117,6 +1117,8 @@ 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); > (cc'ing linux-block and Jens) I'm wondering whether this patch might turn out to be racy. For instance, could a call to __sync_blockdev race with an unmount in such a way that bd_super goes NULL after we check it but before errseq_set is called? If so, what can we do to ensure that that doesn't happen? Any insight here would be appreciated. Thanks, -- Jeff Layton <jlayton@xxxxxxxxxx>
