On 2024/8/15 13:59, Christoph Hellwig wrote: > On Wed, Aug 14, 2024 at 03:49:41PM +0800, Zhang Yi wrote: >> Sorry, this makes me confused. How does this could prevent setting >> redundant dirty bits? >> >> Suppose we have a 3K regular file on a filesystem with 1K block size. >> In iomap_page_mkwrite(), the iter.len is 3K, if the folio size is 4K, >> folio_mark_dirty() will also mark all 4 bits of ifs dirty. And then, >> if we expand this file size to 4K, and this will still lead to a hole >> with dirty bit set but without any block allocated/reserved. Am I >> missing something? > > No, we still need the ifs manipulation in the loop indeed. But > the filemap_dirty_folio (and the not uptodate warning) can still > move outside the iterator. > Yes, right, I misunderstood. Thanks, Yi.
