From: Jeff Layton <jlayton@xxxxxxxxxx> Subject: fs/buffer.c: record blockdev write errors in super_block that it backs 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. Since superblocks are RCU freed, hold the rcu_read_lock to ensure that the superblock doesn't go away while we're marking it. Link: http://lkml.kernel.org/r/20200428135155.19223-3-jlayton@xxxxxxxxxx Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andres Freund <andres@xxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/buffer.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/fs/buffer.c~buffer-record-blockdev-write-errors-in-super_block-that-it-backs +++ a/fs/buffer.c @@ -1154,12 +1154,19 @@ 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_page && bh->b_page->mapping) mapping_set_error(bh->b_page->mapping, -EIO); 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(); } EXPORT_SYMBOL(mark_buffer_write_io_error); _
