On Mon, Jun 24, 2019 at 07:57:07AM -0700, Darrick J. Wong wrote: > On Mon, Jun 24, 2019 at 07:52:45AM +0200, Christoph Hellwig wrote: > > Currently we don't overwrite the flags field in the iomap in > > xfs_bmbt_to_iomap. This works fine with 0-initialized iomaps on stack, > > but is harmful once we want to be able to reuse an iomap in the > > writeback code. > > Is that going to affect all the other iomap users, or is xfs the only > one that assumes zero-initialized iomaps being passed into > ->iomap_begin? 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.