Re: [PATCH] xfs: report a writeback error on a read() call

[Christoph Hellwig <hch@infradead.org>]

On Sun, Jun 22, 2025 at 08:32:18PM +0800, ying chen wrote:
> Normally, user space returns immediately after writing data to the
> buffer cache. However, if an error occurs during the actual disk
> write operation, data loss may ensue, and there is no way to report
> this error back to user space immediately. Current kernels may report
> writeback errors when fsync() is called, but frequent invocations of
> fsync() can degrade performance. Therefore, a new sysctl
> fs.xfs.report_writeback_error_on_read is introduced, which, when set
> to 1, reports writeback errors when read() is called. This allows user
> space to be notified of writeback errors more promptly.

That's really kernel wide policy and not something magic done by a
single file system.