On 10:13 05/08, Dave Chinner wrote:
> On Fri, Aug 02, 2019 at 05:00:40PM -0500, Goldwyn Rodrigues wrote:
> > From: Goldwyn Rodrigues <rgold...@suse.com>
> >
> > Set iomap->type to IOMAP_COW and fill up the source map in case
> > the I/O is not page aligned.
> .....
> > static void btrfs_buffered_page_done(struct inode *inode, loff_t pos,
> > unsigned copied, struct page *page,
> > struct iomap *iomap)
> > @@ -188,6 +217,7 @@ static int btrfs_buffered_iomap_begin(struct inode
> > *inode, loff_t pos,
> > int ret;
> > size_t write_bytes = length;
> > struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> > + size_t end;
> > size_t sector_offset = pos & (fs_info->sectorsize - 1);
> > struct btrfs_iomap *bi;
> >
> > @@ -255,6 +285,17 @@ static int btrfs_buffered_iomap_begin(struct inode
> > *inode, loff_t pos,
> > iomap->private = bi;
> > iomap->length = round_up(write_bytes, fs_info->sectorsize);
> > iomap->offset = round_down(pos, fs_info->sectorsize);
> > + end = pos + write_bytes;
> > + /* Set IOMAP_COW if start/end is not page aligned */
> > + if (((pos & (PAGE_SIZE - 1)) || (end & (PAGE_SIZE - 1)))) {
> > + iomap->type = IOMAP_COW;
> > + ret = get_iomap(inode, pos, length, srcmap);
> > + if (ret < 0)
> > + goto release;
>
> I suspect you didn't test this case, because....
>
> > + } else {
> > + iomap->type = IOMAP_DELALLOC;
> > + }
> > +
> > iomap->addr = IOMAP_NULL_ADDR;
> > iomap->type = IOMAP_DELALLOC;
>
> The iomap->type is overwritten here and so IOMAP_COW will never be
> seen by the iomap infrastructure...
Yes, thats correct. I will fix this.
--
Goldwyn
