Re: [PATCH 2/2] xfs: remove bp->b_error check in xfs_attr3_root_inactive

[Christoph Hellwig <hch@infradead.org>]

On Sat, Dec 21, 2024 at 02:30:43PM +0800, Long Li wrote:
> The xfs_da3_node_read earlier in the function will catch most cases of
> incoming on-disk corruption, which makes this check mostly redundant,
> unless someone corrupts the buffer and the AIL pushes it out to disk
> while the buffer's unlocked.
> 
> In the first case we'll never reach this check, and in the second case
> the AIL will shut down the log, at which point checking b_error becomes
> meaningless. Remove the check to make the code consistent with most other
> xfs_trans_get_buf() callers in XFS.

Hmm. I don't really understand the commit log.  The b_error check
is right after a call to xfs_trans_get_buf_map.  xfs_trans_get_buf_map
either reads the buffer from disk using xfs_buf_get_map which propagates
b_error, or finds it in the transaction, where whoever read it from
disk should have done the same.  So I think the change looks fine,
but I don't think the commit log really explains it very well.