On Mon, Aug 28, 2023 at 02:32:59PM +0200, Christoph Hellwig wrote: > On Sun, Aug 27, 2023 at 10:45:18PM +0100, Al Viro wrote: > > IOW, I suspect that the right thing to do would be something along the lines > > of > > The idea looks sensible to me, but we'll also need to do it for the > filemap_write_and_wait_range failure case.
Huh? That's precisely where this patch is doing that... That function in mainline is if (unlikely(buffered_written < 0)) { if (direct_written) return direct_written; return buffered_written; } /* * We need to ensure that the page cache pages are written to disk and * invalidated to preserve the expected O_DIRECT semantics. */ err = filemap_write_and_wait_range(mapping, pos, end); if (err < 0) { /* * We don't know how much we wrote, so just return the number of * bytes which were direct-written */ if (direct_written) return direct_written; return err; } invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); return direct_written + buffered_written; The first failure exit does not need any work - the caller had not bumped ->ki_pos; the second one (after that 'if (err < 0) {' line) does and that's where the patch upthread adds iocb->ki_pos -= buffered_written. Or am I completely misparsing what you've written?