On Tue, Jun 25, 2019 at 08:13:57AM -0700, Darrick J. Wong wrote: > > This doesn't affect any existing user as they all get a zeroed iomap > > passed from the caller in iomap.c. It affects the writeback code > > once it uses struct iomap as it overwrites a previously used iomap. > > Then shouldn't this new writeback code zero the iomap before calling > back into the filesystem, just to maintain consistent behavior?
The core code doesn't decide when to overwrite it, that ->map_blocks method does that based on a few factors (including the data_seq/cow_seq counters that are entirely inside xfs).
