On Thu, Nov 23, 2023 at 08:51:14PM +0800, Zhang Yi wrote:
> index fd4d43bafd1b..3b9ba390dd1b 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -852,13 +852,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
> * cache. It's up to the file system to write the updated size to disk,
> * preferably after I/O completion so that no stale data is exposed.
> */
> - if (pos + ret > old_size) {
> + if ((iter->flags & IOMAP_WRITE) && pos + ret > old_size) {
> i_size_write(iter->inode, pos + ret);
> iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
> }
> __iomap_put_folio(iter, pos, ret, folio);
>
> - if (old_size < pos)
> + if ((iter->flags & IOMAP_WRITE) && old_size < pos)
> pagecache_isize_extended(iter->inode, old_size, pos);
> if (ret < len)
> iomap_write_failed(iter->inode, pos + ret, len - ret);
I agree with your rationale, but I hate how this code ends up
looking. In many ways iomap_write_end seems like the wrong
place to update the inode size anyway. I've not done a deep
analysis, but I think there shouldn't really be any major blocker
to only setting IOMAP_F_SIZE_CHANGED in iomap_write_end, and then
move updating i_size and calling pagecache_isize_extended to
iomap_write_iter.
